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Sample records for intra-hepatic porto-systemic shunt

  1. Bilhemia after trans-jugular intra-hepatic porto-systemic shunt and its management with biliary decompression

    PubMed Central

    Singal, Ashwani K; Kathuria, Manoj K; Malhotra, Advitya; Goodgame, Richard W; Soloway, Roger D

    2009-01-01

    Bilhemia or bile mixing with blood is a rare clinical problem. The clinical presentation is usually transient self-resolving hyperbilirubinemia, progressive and rapidly rising conjugated hyperbilirubinemia, or recurrent cholangitis. Endoscopic retrograde cholangiopancreatography (ERCP) plays an important role in diagnosis and management. Biliary decompression with endoscopic sphincterotomy is useful in treating these patients. If not recognized and treated in time, the condition can be fatal in a significant proportion of patients. This usually occurs after blunt or penetrating hepatic trauma due to a fistulous connection between the biliary radicle and portal or hepatic venous radical. Cases have been described due to iatrogenic trauma such as liver biopsy and percutaneous biliary drainage. However, the occurrence after trans-jugular intra-hepatic porto-systemic shunt (TIPS) is very rare. We report a case of bilhemia presenting as rapidly rising bilirubin after TIPS. The patient was managed successfully with ERCP and removal of a blood clot from the common bile duct. PMID:19653349

  2. Transjugular Intrahepatic Porto-Systemic Shunt Placement in a Patient with Left-Lateral Split-Liver Transplant and Mesenterico-Left Portal Vein by Pass Placement

    SciTech Connect

    Miraglia, Roberto Maruzzelli, Luigi; Luca, Angelo

    2011-12-15

    This is a report of a successful placement of a transjugular intrahepatic porto-systemic shunt in a young patient with previous left-lateral, split-liver transplant and mesenterico-left portal vein by pass placement after posttransplant extrahepatic portal vein thrombosis.

  3. Technical concepts for vascular electromagnetic navigated interventions: aortic in situ fenestration and transjugular intrahepatic porto-systemic shunts.

    PubMed

    Penzkofer, Tobias; Isfort, Peter; Na, Hong-Sik; Wilkmann, Christoph; Osterhues, Sabine; Besting, Andreas; Hänisch, Christoph; Bisplinghoff, Stefan; Jansing, Johannes; von Werder, Sylvie; Gooding, Jorge; de la Fuente, Mathias; Mahnken, Andreas H; Disselhorst-Klug, Catherine; Schmitz-Rode, Thomas; Kuhl, Christiane K; Bruners, Philipp

    2014-04-01

    This work presents concepts for complex endovascular procedures using electromagnetic navigation technology (EMT). Navigation software interfacing a standard commercially available navigation system was developed, featuring registration, electromagnetic field distortion correction, breathing motion detection and gating, and state-of-the-art 3D imaging post processing. Protocols for endovascularly placed, in-situ fenestrated abdominal aortic stent grafts and an EMT guided transjugular intrahepatic portosystemic shunt (TIPSS) creation have been designed. A dedicated set of interventional devices was developed for each of the procedures: For aortic in-situ fenestration a combination of high-porosity stentgrafts, steerable catheters and electromagnetically navigated guidewires was used, for TIPSS a dual-navigated (sheath and stylet) TIPSS-device was designed and manufactured. The developed devices underwent phantom testing, in preparation for animal experiments to prove the feasibility of the approach. Once established, these systems could aid in performing these challenging interventional radiology procedures, exploiting the unique characteristics of electromagnetic navigation and solving multiple of the problems associated with these interventions being performed under X-ray fluoroscopy, such as lacking real-time 3D information or extensive exposure to ionizing radiation.

  4. Iron Deficiency Impairs Intra-Hepatic Lymphocyte Mediated Immune Response

    PubMed Central

    Lozano, Juan José; Martinez-Picola, Marta; Kodela, Elisavet; Mas-Malavila, Roser; Bruguera, Miquel; Collins, Helen L.; Hider, Robert C.; Martinez-Llordella, Marc; Sanchez-Fueyo, Alberto

    2015-01-01

    Hepatic expression of iron homeostasis genes and serum iron parameters predict the success of immunosuppression withdrawal following clinical liver transplantation, a phenomenon known as spontaneous operational tolerance. In experimental animal models, spontaneous liver allograft tolerance is established through a process that requires intra-hepatic lymphocyte activation and deletion. Our aim was to determine if changes in systemic iron status regulate intra-hepatic lymphocyte responses. We used a murine model of lymphocyte-mediated acute liver inflammation induced by Concanavalin A (ConA) injection employing mice fed with an iron-deficient (IrDef) or an iron-balanced diet (IrRepl). While the mild iron deficiency induced by the IrDef diet did not significantly modify the steady state immune cell repertoire and systemic cytokine levels, it significantly dampened inflammatory liver damage after ConA challenge. These findings were associated with a marked decrease in T cell and NKT cell activation following ConA injection in IrDef mice. The decreased liver injury observed in IrDef mice was independent from changes in the gut microflora, and was replicated employing an iron specific chelator that did not modify intra-hepatic hepcidin secretion. Furthermore, low-dose iron chelation markedly impaired the activation of isolated T cells in vitro. All together, these results suggest that small changes in iron homeostasis can have a major effect in the regulation of intra-hepatic lymphocyte mediated responses. PMID:26287688

  5. Spontaneous intra-hepatic haemorrhage in a patient with fever of unknown origin.

    PubMed

    Leung, Vincent K S; Lam, Clement Y W; Chan, C C; Ng, W L; Loke, Tony K L; Luk, I Sc; Chau, T N; Wu, Arthur H W; Fong, W N; Lam, S H

    2007-08-01

    Polyarteritis nodosa is a systemic necrotising vasculitis that affects the small- and medium-sized arteries. Multifocal aneurysmal formation in the renal, hepatic, and mesenteric vasculature is a hallmark of this condition, and spontaneous aneurysmal rupture may occur, resulting in life-threatening haemorrhage. We describe a 42-year-old man who initially presented with fever of unknown origin. A diagnosis could not be reached at that time despite extensive investigations. The fever subsided spontaneously after 8 weeks, and the patient remained well for 6 years until he was admitted again for evaluation of fever. During his hospital stay, he developed a spontaneous massive intra-hepatic haemorrhage resulting in hepatic rupture and a haemoperitoneum. The bleeding was controlled at emergency laparotomy. An abdominal angiography demonstrated multiple microaneurysms in the hepatic and mesenteric arterial vasculature. The clinical findings suggested polyarteritis nodosa, and the source of bleeding was probably a ruptured intra-hepatic artery aneurysm.

  6. Ventriculoperitoneal shunting

    MedlinePlus

    The person may need to lie flat for 24 hours the first time a shunt is placed. How long the hospital stay is depends on the reason the shunt is needed. The health care team will ... Follow the provider's instructions about how to take care of ...

  7. Transjugular Intrahepatic Portosystemic Shunt Dysfunction: Concordance of Clinical Findings, Doppler Ultrasound Examination, and Shunt Venography

    PubMed Central

    Owen, Joshua M; Gaba, Ron Charles

    2016-01-01

    Objectives: The objective of this study was to evaluate the concordance between clinical symptoms, Doppler ultrasound (US), and shunt venography for the detection of stent-graft transjugular intrahepatic portosystemic shunt (TIPS) dysfunction. Materials and Methods: Forty-one patients (M:F 30:11, median age 55 years) who underwent contemporaneous clinical exam, Doppler US, and TIPS venography between 2003 and 2014 were retrospectively studied. Clinical symptoms (recurrent ascites or variceal bleeding) were dichotomously classified as present/absent, and US and TIPS venograms were categorized in a binary fashion as normal/abnormal. US abnormalities included high/low (>190 or <90 cm/s) TIPS velocity, significant velocity rise/fall (>50 cm/s), absent flow, and return of antegrade intra-hepatic portal flow. Venographic abnormalities included shunt stenosis/occlusion and/or pressure gradient elevation. Clinical and imaging concordance rates were calculated. Results: Fifty-two corresponding US examinations and venograms were assessed. The median time between studies was 3 days. Forty of 52 (77%) patients were symptomatic, 33/52 (64%) US examinations were abnormal, and 20/52 (38%) TIPS venograms were abnormal. Concordance between clinical symptoms and TIPS venography was 48% (25/52), while the agreement between US and shunt venography was 65% (34/52). Clinical symptoms and the US concurred in 60% (31/52) of the patients. The sensitivity of clinical symptoms and US for the detection of venographically abnormal shunts was 80% (16/20) and 85% (17/20), respectively. Both clinical symptoms and the US had low specificity (25%, 8/32 and 50%, 16/32) for venographically abnormal shunts. Conclusion: Clinical findings and the US had low concordance rates with TIPS venography, with acceptable sensitivity but poor specificity. These findings suggest the need for improved noninvasive imaging methods for stent-graft TIPS surveillance. PMID:27563495

  8. Ventriculoperitoneal shunt - discharge

    MedlinePlus

    ... ventriculoperitoneal - discharge; VP shunt - discharge; Shunt revision - discharge; Hydrocephalus shunt placement - discharge ... Your child has hydrocephalus and needed a shunt placed to drain excess fluid and relieve pressure in the brain. This buildup of brain ...

  9. Distal splenorenal shunt

    MedlinePlus

    ... shunt procedure; Renal - splenic venous shunt; Warren shunt; Cirrhosis - distal splenorenal; Liver failure - distal splenorenal ... hepatitis Blood clots Certain congenital disorders Primary biliary cirrhosis When blood cannot flow normally through the portal ...

  10. Direct measurement of porto-systemic gradient in a failing Fontan circulation.

    PubMed

    Velpula, Madhavi; Sheron, Nick; Guha, Neill; Salmon, Tony; Hacking, Nigel; Veldtman, Gruschen R

    2011-01-01

    We describe the case history of a 42-year-old man with cardiac cirrhosis, portal hypertension, and life-threatening variceal bleeding after Fontan revision surgery. Direct pressure measurements in the portal vein, though high, demonstrated only a modest portosystemic gradient (PSG), 9 mm Hg. A transjugular intrahepatic portosystemic shunt procedure was performed. This reduced the PSG (3 mm Hg). His bleeding was controlled. The patient's histopathological findings were identical to that previously documented in Fontan patients, raising the question of whether these subdiaphragmatic hemodynamics are representative of the broader failing Fontan population. PMID:21356034

  11. Ventriculomammary shunt: an unusual ventriculoperitoneal shunt complication.

    PubMed

    Chaudhry, Nauman S; Johnson, Jeremiah N; Morcos, Jacques J

    2015-02-01

    Ventriculoperitoneal (VP) shunt malfunctions are common and can result in significant consequences for patients. Despite the prevalence of breast augmentation surgery and breast surgery for other pathologies, few breast related VP shunt complications have been reported. A 54-year-old woman with hydrocephalus post-subarachnoid hemorrhage returned 1 month after VP shunt placement complaining of painful unilateral breast enlargement. After investigation, it was determined that the distal VP shunt catheter had migrated from the peritoneal cavity into the breast and wrapped around her breast implant. The breast enlargement was the result of cerebrospinal fluid retention. We detail this unusual case and review all breast related VP shunt complications reported in the literature. To avoid breast related complications related to VP shunt procedures, it is important to illicit pre-procedural history regarding breast implants, evade indwelling implants during catheter tunneling and carefully securing the abdominal catheter to prevent retrograde catheter migration to the breast.

  12. Polytetrafluoroethylene sponge syringosubarachnoid shunt.

    PubMed

    Chagla, Aadil S; Kansal, Ritesh; Srikant, Balasubramaniam

    2011-01-01

    Syringomyelia is condition in which a cyst or cavity forms inside the spinal cavity. Its management always remains a difficult. A variety of surgical techniques have been used in management of syringomyelia. Syringosubarachnoid shunt remains an effective method in management of syringomyelia. Shunt tube obstruction remains an important complication of shunt procedure. We describe a novel technique of use of polytetrafluoroethylene sponge shunt for syringosubarachnoid shunt in patient with large syrinx and Chiari 1 malformation. Polytetrafluoroethylene sponge is a non irritant material with multiple porosities that is less susceptible to blockages or kinking. It could provide a good alternative technique in syringosubarachnoid shunting.

  13. Hydrocephalus and Shunts

    MedlinePlus

    ... or anesthesia. When ventricles start to get too big, it is a strong sign that the shunt is not working right. It is important to know that some people (between 5 and 15 percent) with Spina Bilda may have ...

  14. Shunt tube calcification as a late complication of ventriculoperitoneal shunting

    PubMed Central

    Salim, Abubakr Darrag; Elzain, Mohammed Awad; Mohamed, Haddab Ahmed; Ibrahim Zayan, Baha Eldin Mohamed

    2015-01-01

    Shunt calcification is a rare complication of ventriculoperitoneal shunting that occurs years later after the initial operation this condition is rarely reported in literature. Two patients with shunt calcifications were described. The first patient was 17-year-old lady who had congenital hydrocephalus and shunted in the early infancy, she was presented recently complaining of itching of the skin along the shunt track and limitation of neck movement. The patient was then operated with removal of the old peritoneal catheter and replacing it with a new one. The second patient was 17-year-old boy originally was a case of posterior fossa pilocytic astrocytoma associated with obstructive hydrocephalus, he was operated with both shunting for the hydrocephalus and tumor removal, 6 years later he presented with shunt exposure. Calcification of the shunt tube was discovered intraoperatively upon shunt removal. Shunt calcification has been observed mainly in barium-impregnated catheters. Introducing plain silicone-coated shunt tubing may reduce the rate of this condition. The usual complaints of the patients suffering from this condition are pain in the neck and chest wall along the shunt pathway and limitation of the neck movement due to shunt tube tethering, but features of shunt dysfunction and skin irritation above the shunt may be present. In this review, plain X-ray and operative findings showed that the most extensive calcification is present in the neck, where the catheters were subject to heavy mechanical stress. Disturbed calcium and phosphate metabolisms may be involved in this condition. Shunt calcification is a rare condition that occurs due to material aging presenting with features of shunt tethering, dysfunction or overlying skin irritation. Plain X-ray is needed to detect calcification while shunt removal, replacement or endoscopic third ventriculostomy may carry solution for this condition. PMID:26396620

  15. TRANSJUGULAR INTRAHEPATIC PORTOSYSTEMIC SHUNT

    PubMed Central

    Patidar, Kavish R.; Sydnor, Malcolm; Sanyal, Arun J.

    2014-01-01

    Transjugular intrahepatic portosystemic shunt (TIPS) is an established procedure for the complications of portal hypertension. The largest body of evidence for its use has been supported for recurrent or refractory variceal bleeding and refractory ascites. Its use has also been advocated for acute variceal bleed, hepatic hydrothorax, and hepatorenal syndrome. With the replacement of bare metal stents with polytetrafluoroethylen (PTFE) covered stents, shunt patency has improved dramatically thus improving outcomes. Therefore, reassessment of its utility, management of its complications, and understanding of various TIPS techniques is important. PMID:25438287

  16. Activated Kupffer cells play an important role in intra-hepatic Th1-associated necro-inflammation in Concanavalin A-induced hepatic injury in mice.

    PubMed

    Morita, Atsuhiro; Itoh, Yoshito; Toyama, Tetsuya; Fujii, Hideki; Nishioji, Kenichi; Kirishima, Toshihiko; Makiyama, Akiko; Yamauchi, Norihito; Okanoue, Takeshi

    2003-10-01

    BACKGROUND/AIMS: To examine whether or not activated Kupffer cells play an important role in intra-hepatic Th1-associated necro-inflammation in Concanavalin A (Con A)-induced hepatic injury in mice. METHODS: Con A was administered to Balb/c mice pretreated with or without gadolinium chloride (GdCl(3)). Kupffer cell activation was evaluated by their ability to produce superoxide anions in situ under liver perfusion with nitro blue tetrazolium (NBT). Hepatic concentration of cytokines was measured by ELISA and the mRNA expression of CXC chemokine receptor 3 (CXCR3) was evaluated by RT-PCR. Immunohistochemical detection of CD4 positive lymphocytes in the liver was also performed. RESULTS: GdCl(3)-pretreatment significantly (P<0.01) reduced the serum levels of alanine aminotransferase (ALT) in Con A-treated mice. Formazan deposition in Kupffer cells, the hepatic concentration of tumor necrosis factor-alpha and interferon-gamma, the mRNA expression of CXCR3 and the CD4 positive lymphocytes in the liver were decreased in GdCl(3)-pretreated mice as compared with those without GdCl(3)-pretreatment (P<0.05, respectively). CONCLUSIONS: Activated Kupffer cells, which produce superoxide anions, are involved in Con A-induced hepatic necro-inflammation in mice possibly through the activation of Th1-associated immune response mediated by CD4 and/or CXCR3 positive cells recruited into the liver.

  17. [Extraneural metastasis of pineal germinoma through a ventriculoperitoneal shunt, following histological change].

    PubMed

    Uchino, M; Nemoto, M; Ohtsuka, T; Seiki, Y; Shibata, I

    1999-03-01

    Primary germinoma of the central nervous system carries a good prognosis because of their radiosensitivity. Recurrence is rare and extraneural metastases are even more unusual. We report a unique case of a primary intracranial germinoma exhibiting complete response to radiotherapy, but recurring as an intra-abdominal yolk sac tumor. The presence of a VP shunt is thought to have facilitated metastatic spread of the intracranial neoplasm. An 21-year-old (corrected) male was admitted with headache and consciousness disturbance. Computed tomography (CT) revealed an enhanced tumor of the pineal region and hydrocephalus. A ventriculo-peritoneal shunt was emplaced immediately. No serum tumor markers such as alpha-fetoprotein or human chorionic gonadotropin were detectable. A test dose of radiotherapy (whole brain 20Gy) was given. The tumor size was remarkably decreased. Clinical diagnosis was germinoma. Additional whole brain radiation (total 45Gy) and whole spine radiation (20Gy) were given. The tumor and the hydrocephalus regressed completely and the patient returned to school. Three years later, he experienced a feeling of abdominal fullness. CT and echotomography of the abdomen showed a large peritoneal and intra-hepatic tumor. But MRI revealed no recurrent tumor of the pineal lesion or of the other areas in the central nervous system. Radiological and clinical findings showed no tumors in the testis, the retroperitoneal cavity, or the thymus. Laboratory investigation demonstrated elevated serum AFP (26,550 ng/ml). AFP level regressed after combined chemotherapy. However, the patient died due to pneumonia and multiple organ failure. Only needle necropsy was performed. The microscopic appearance of the peritoneal tumor was confirmed to be an endodermal sinus tumor. It was suspected to be a metastasis of the pineal tumor through the V-P shunt system.

  18. Subgaleal migration of a ventriculoperitoneal shunt.

    PubMed

    Al Hinai, Qasim S; Pawar, Sanjay J; Sharma, Rewati Raman; Devadas, R V

    2006-07-01

    Blockage of a ventriculoperitoneal (VP) shunt is very common. Here, we describe an unusual case of shunt blockage in an infant. He was shunted for hydrocephalus associated with a Dandy-Walker malformation diagnosed at birth. At surgery, the entire VP shunt was found to have migrated into the subgaleal space, which clinically presented as shunt obstruction. We suggest techniques to avoid this rare, but preventable, complication of shunt surgery.

  19. 30 CFR 56.6401 - Shunting.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shunting. 56.6401 Section 56.6401 Mineral....6401 Shunting. Except during testing— (a) Electric detonators shall be kept shunted until connected to the blasting line or wired into a blasting round; (b) Wired rounds shall be kept shunted...

  20. To shunt or not to shunt: hydrocephalus and dysraphism.

    PubMed

    Rekate, H L

    1985-01-01

    Objective criteria are available for decision making in children with ventriculomegaly and spina bifida cystica. Figure 29.7 is the evaluation algorithm used in the Hydrocephalus/Myelodysplasia Clinic at Rainbow Babies and Children's Hospital. In children without serious neurosurgical complications such as the Chiari crisis or problems with wound healing, we rely on three reasonably objective measurements for decision making. Head circumference: Measured daily while in hospital and at each visit. If the pattern of head growth crosses multiple percentile lines indicating that the child will be severely megalencephalic, a shunt will be performed. Ultrasonography: Ultrasound determinations are made in the first few days of life, prior to discharge, at 6 weeks of age, and each 6 weeks of age until 6 months. Some measurements of ventricular size (usually CT scan because of a small anterior fontanelle) should be made at age 1 year. Denver Developmental Testing (DDST): These are performed at age 6 weeks and each 6 weeks thereafter. If the child shows significant ventriculomegaly, a shunt is performed. When the results are questionable the decision is delayed and the test repeated in 6 weeks. Whether a shunt is or is not placed in an infant with ventriculomegaly and myelodysplasia, follow-up must remain compulsive. Following shunting, not only should the head circumference stabilize, but the cortical mantle should increase. Often children shunted in this situation fail to show signs of increased intracranial pressure with shunt malfunction and must be followed with serial head circumference measurements as well as ultrasounds and CT scans. If the decision is made not to shunt the child the work of Hall et al. (10) would suggest the possibility that later in life shunts may be needed to prevent scoliosis secondary to hydromyelia. More information is needed as the aggressively treated population become adults. PMID:2415285

  1. [Clinical analysis of pediatric shunt catheter fracture].

    PubMed

    Morishita, Akitsugu; Nagashima, Tatsuya; Kurata, Hiromitsu; Eguchi, Takahiro; Tamaki, Norihiko

    2002-08-01

    Between 1985 and 1998, 415 shunt dysfunctions occurred at Kobe Children's Hospital. The main reasons for shunt revision were obstruction of the catheter, shunt infection, and shunt disconnection. This report presents an analysis of 35 patients (36 cases) who underwent a ventriculoperitoneal (VP) shunt revision because of shunt catheter fracture. All patients were less than 18 years old. We researched their age at the time of revision, site of disruption, postoperative period, shunt system, clinical symptoms, and other factors. The mechanical aspects of shunt catheter fracture are also discussed in this report. The peak time of shunt catheter fracture was the time when children were growing up and were entering elementary school. In other words, when their height was increasing rapidly. At that time, the distal catheter is subjected to traction between the valve and the abdomen at the site of insertion in either the upper or lower direction. However, physical examination of the shunt catheter showed normal range. Additional contributory factors were chronic stimulation at the occipital bone, clavium bone, and costal arch, while movement of the neck and body rotation also caused shunt catheter fracture. These factors all originated from shearing strain at the shunt catheter. We look forward to the introduction of a stronger shunt catheter, because surgical repair time must be minimized to protect the child's mental development. In addition, shearing strain at the shunt catheter needs special attention.

  2. 49 CFR 236.838 - Wire, shunt.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Wire, shunt. 236.838 Section 236.838 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Wire, shunt. A wire forming part of a shunt circuit....

  3. 30 CFR 57.6401 - Shunting.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shunting. 57.6401 Section 57.6401 Mineral...-Surface and Underground § 57.6401 Shunting. Except during testing— (a) Electric detonators shall be kept shunted until connected to the blasting line or wired into a blasting round; (b) Wired rounds shall...

  4. Disconnection as a cause of ventriculoperitoneal shunt malfunction in multicomponent shunt systems.

    PubMed

    Aldrich, E F; Harmann, P

    The cause of malfunction in 275 consecutive ventriculoperitoneal (VP) shunt revisions over an 8-year period were retrospectively analyzed. In all cases the shunt revised was a multicomponent (Holter) VP shunt. Disconnections in the system accounted for 41 (15%) of the malfunctions. The more distal the connection was from the ventricle, the higher the likelihood of disconnection. Furthermore, occipitally placed shunts had a significantly higher tendency to dislocate than frontally placed shunts.

  5. Students with Shunts: Program Considerations.

    ERIC Educational Resources Information Center

    French, Ron; And Others

    1997-01-01

    Examines how the medical condition of hydrocephalus can affect physical education students and physical education programs, and stresses the need to provide physical educators with information on students' medical conditions. Describes hydrocephalus and its treatment with ventricular peritoneal shunts, and offers suggestions on modifying…

  6. Ventriculoperitoneal shunt perforations of the gastrointestinal tract.

    PubMed

    Thiong'o, Grace Muthoni; Luzzio, Christopher; Albright, A Leland

    2015-07-01

    OBJECT The purposes of this study were to evaluate the frequency with which children presented with ventriculoperitoneal (VP) shunt perforations of the gastrointestinal (GI) tract, to determine the type of shunts that caused the perforations, and to compare the stiffness of perforating catheters with the stiffness of catheters from other manufacturers. METHODS Medical records were reviewed of 197 children who were admitted with VP shunt malfunction. Catheter stiffness was evaluated by measuring relative resistance to cross-sectional compression, resistance to column buckling, and elasticity in longitudinal bending. Catheter frictional force was measured per unit length. RESULTS Six children were identified whose VP shunts had perforated the GI tract; 2 shunts subsequently protruded through the anal orifice, 1 protruded through the oral cavity, and 3 presented with subcutaneous abscesses that tracked upward from the intestine to the chest. All perforating shunts were Chhabra shunts. Catheter stiffness and resistance to bending were greatest with a Medtronic shunt catheter, intermediate with a Codman catheter, and least with a Chhabra catheter. Frictional force was greatest with a Chhabra catheter and least with a Medtronic catheter. CONCLUSIONS The frequency of perforations by Chhabra shunts appears to be higher than the frequency associated with other shunts. The increased frequency does not correlate with their stiffness but may reflect their greater frictional forces.

  7. Shunt regulation electric power system

    NASA Technical Reports Server (NTRS)

    Wright, W. H.; Bless, J. J. (Inventor)

    1971-01-01

    A regulated electric power system having load and return bus lines is described. A plurality of solar cells interconnected in a power supplying relationship and having a power shunt tap point electrically spaced from the bus lines is provided. A power dissipator is connected to the shunt tap point and provides for a controllable dissipation of excess energy supplied by the solar cells. A dissipation driver is coupled to the power dissipator and controls its conductance and dissipation and is also connected to the solar cells in a power taping relationship to derive operating power therefrom. An error signal generator is coupled to the load bus and to a reference signal generator to provide an error output signal which is representative of the difference between the electric parameters existing at the load bus and the reference signal generator. An error amplifier is coupled to the error signal generator and the dissipation driver to provide the driver with controlling signals.

  8. A wireless monitoring system for Hydrocephalus shunts.

    PubMed

    Narayanaswamy, A; Nourani, M; Tamil, L; Bianco, S

    2015-08-01

    Patients with Hydrocephalus are usually treated by diverting the excess Cerebrospinal Fluid (CSF) to other parts of the body using shunts. More than 40 percentage of shunts implanted fail within the first two years. Obstruction in the shunts is one of the major causes of failure (45 percent) and the detection of obstruction reduces the complexity of the revision surgery. This paper describes a proposed wireless monitoring system for clog detection and flow measurement in shunts. A prototype was built using multiple pressure sensors along the shunt catheters for sensing the location of clog and flow rate. Regular monitoring of flow rates can be used to adjust the valve in the shunt to prevent over drainage or under drainage of CSF. The accuracy of the flow measurement is more than 90 percent.

  9. Cell shunt resistance and photovoltaic module performance

    SciTech Connect

    McMahon, T.J.; Basso, T.S.; Rummel, S.R.

    1996-09-01

    Shunt resistance of cells in photovoltaic modules can affect module power output and could indicate flawed manufacturing processes and reliability problems. The authors describe a two-terminal diagnostic method to directly measure the shunt resistance of individual cells in a series-connected module non-intrusively, without deencapsulation. Peak power efficiency vs. light intensity was measured on a 12-cell, series-connected, single crystalline module having relatively high cell shunt resistances. The module was remeasured with 0.5-, 1-, and 2-ohm resistors attached across each cell to simulate shunt resistances of several emerging technologies. Peak power efficiencies decreased dramatically at lower light levels. Using the PSpice circuit simulator, they verified that cell shunt and series resistances can indeed be responsible for the observed peak power efficiency vs. intensity behavior. They discuss the effect of basic cell diode parameters, i.e., shunt resistance, series resistance, and recombination losses, on PV module performance as a function of light intensity.

  10. [Infection of cerebrospinal fluid shunt systems].

    PubMed

    Jiménez-Mejías, Manuel E; García-Cabrera, Emilio

    2008-04-01

    Cerebrospinal fluid (CSF) shunt infection is a cause of considerable morbidity and mortality. Shunt infection is produced mainly during surgery and by surgical wound infection. Staphylococcus spp. (> 50% methicillin-resistant) are the most common causative bacteria, although gram-negative bacilli (10%-25%) and Propionibacterium acnes are becoming increasingly implicated. Shunt malfunction syndrome and fever are the most frequent clinical manifestations, whereas signs of meningeal irritation are uncommon. Other clinical manifestations depend on the location of the distal catheter. CSF should be obtained by puncture of the shunt reservoir or the distal catheter and processed for biochemical analyses, cell count, Gram stain, and aerobic and anaerobic cultures (lengthy incubation). Because of biofilm formation and to avoid recurrences, the recommended treatment is intravenous antibiotics plus removal of all components of the infected shunt, followed by placement of an external drainage catheter and a new shunt. Prophylaxis is important and can include antimicrobial prophylaxis and/or antibiotic-impregnated catheters.

  11. Arterioportal shunts on dynamic computed tomography

    SciTech Connect

    Nakayama, T.; Hiyama, Y.; Ohnishi, K.; Tsuchiya, S.; Kohno, K.; Nakajima, Y.; Okuda, K.

    1983-05-01

    Thirty-two patients, 20 with hepatocelluar carcinoma and 12 with liver cirrhosis, were examined by dynamic computed tomography (CT) using intravenous bolus injection of contrast medium and by celiac angiography. Dynamic CT disclosed arterioportal shunting in four cases of hepatocellular carcinoma and in one of cirrhosis. In three of the former, the arterioportal shunt was adjacent to a mass lesion on CT, suggesting tumor invasion into the portal branch. In one with hepatocellular carcinoma, the shunt was remote from the mass. In the case with cirrhosis, there was no mass. In these last two cases, the shunt might have been caused by prior percutaneous needle puncture. In another case of hepatocellular carcinoma, celiac angiography but not CT demonstrated an arterioportal shunt. Thus, dynamic CT was diagnostic in five of six cases of arteriographically demonstrated arterioportal shunts.

  12. 21 CFR 886.3920 - Aqueous shunt.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Aqueous shunt. 886.3920 Section 886.3920 Food and... OPHTHALMIC DEVICES Prosthetic Devices § 886.3920 Aqueous shunt. (a) Identification. An aqueous shunt is an... Review Guidance of 2/12/90 (K90-1),” and (3) “Aqueous Shunts—510(k) Submissions.”...

  13. Radiological Insertion and Management of Peritoneovenous Shunt

    SciTech Connect

    Bratby, M. J.; Hussain, F. F. Lopez, A. J.

    2007-06-15

    The purpose of the study was to report our experience of the management of complications following the insertion of a peritoneovenous shunt for intractable malignant ascites. From June 1999 to January 2006, 26 patients underwent insertion of a peritoneovenous shunt for ascites by interventional radiologists. We have used ultrasound and shuntography to assist in the diagnosis of the cause of shunt blockage. Successful techniques for the restoration of the shunt function include port- pumping, stripping of any fibrin sheath, and revision of either the venous or peritoneal catheter. The procedure was initially successful in all patients with continued patency until death in 17. A further four patients are still alive with a functioning shunt. There was one rapid postprocedure death resulting from pulmonary edema. Two patients developed pneumothorax, managed successfully with either a chest drain or aspiration. Shunt dysfunction occurred eight times in seven patients. There were five successful revisions in four patients. Overall, shunt patency has been maintained in 80.1% of patients. Shunt dysfunction is seen in a significant number of patients, but successful revision of the shunt can be achieved in the majority.

  14. [Unusual abdominal complication of ventriculoperitoneal shunt].

    PubMed

    Guillén, A; Costa, J M; Castelló, I; Claramunt, E; Cardona, E

    2002-10-01

    The most common complications after CSF shunting to treat hydrocephalus are shunt infection and obstruction. Although ventriculoperitoneal (VP) diversion of the CSF using artificial shunt devices is an accepted method for the management of hydrocephalus, high rates of various complications have been reported, ranging from 24% to 47%. Among these, abdominal complications account for approximately 25%. The incidence of bowel perforation by shunt-catheter is known to be as low as 0.1-0.7%. We describe a case of migration af a peritoneal catheter through a congenital hernia of Morgagni.

  15. [Glypressin and emergency sclerotherapy, deferred emergency shunt (Warren, portacaval, mesocaval): new tactics in the treatment of severe hemorrhage by esophagogastric varices in cirrhotic patients].

    PubMed

    Huscher, C; Biraghi, M; Chiodini, S; Recher, A; Torri, F; Zamboni, F

    1990-01-01

    Transplenic decompression of esophageal varices by distal splenorenal shunt according to Warren (DSRS) aims to a selective detention of the esophago-gastric varices, also assuring an adequate portal perfusion and hypertensive state of the porto-mesenteric district. The DSRS though, should and must not be performed in emergency as a high mortality rate is registered in all cases of emergency porto-systemic derivations. A mortality risk is reported even during endoscopic sclerosis if performed in emergency compared to the elective procedure. The scope of our study was to test the validity of a new approach of the hemorrhagic cirrhotic patient: the end point was to stop the bleeding with Glypressin and deferred sclerotherapy, associating a selective shunt at 40-60 days. Out of 32 patients with esophago-gastric variceal bleeding, 8 were selected also for derivative surgery. Results show Glypressin as the first and best therapeutic approach. The drug in many cases stops bleeding or at least reduces the blood loss allowing an easier endoscopic sclerosis. Further sclerosis and/or surgical therapy may assure variceal eradication.

  16. Headaches in patients with shunts.

    PubMed

    Rekate, Harold L; Kranz, Dory

    2009-03-01

    Headache is one of the most common afflictions suffered by humans. Headache in patients with a shunt triggers a series of events that includes utilization of expensive technologies and often potentially dangerous surgical intervention. The purpose of this study was to determine the incidence of headaches in patients with shunts and, hopefully, the relationship of those headache disorders to the treatment of hydrocephalus. The Hydrocephalus Association maintains a self-reporting database recorded from individuals treated for hydrocephalus and their families. This database was mined to determine the incidence of severe headaches requiring treatment and interfering with normal life in patients who have been treated for hydrocephalus. There were 1,242 responders between the ages of 19 months and 45 years of age. Of these, 1,233 answered the question, "Do you or your family member suffer from (does your child complain of) frequent or chronic headaches?" This subset forms the basis of this study. Three groups were defined by age: children (19 months-12 years), adolescents (13 years-19 years), and young adults (20 years-45 years). Most respondents were initially treated during infancy (before 18 months of age); 84% of children and 69% of both adolescents and young adults were treated very early in life. Severe headaches became a more frequent problem as the age of the population treated for hydrocephalus increased. In terms of frequency and severity of headaches, direct comparisons with epidemiologic studies of normal populations are difficult because of the limitations of data available in the database. However, it is likely that this population has a higher incidence of severe headaches than normal populations. The cost of management of headaches in this population is very high, and the patients are at risk throughout life. Early treatment decisions have a significant effect on later quality of life. Strategies that lead to normalization of cerebrospinal fluid dynamics

  17. 21 CFR 882.4545 - Shunt system implantation instrument.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... the implantation of cerebrospinal fluid shunts, and includes tunneling instruments for passing shunt components under the skin. (b) Classification. Class I (general controls). When made only of surgical...

  18. 21 CFR 882.4545 - Shunt system implantation instrument.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... the implantation of cerebrospinal fluid shunts, and includes tunneling instruments for passing shunt components under the skin. (b) Classification. Class I (general controls). When made only of surgical...

  19. 49 CFR 236.802 - Shunt.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Shunt. 236.802 Section 236.802 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.802 Shunt. A...

  20. 21 CFR 874.3820 - Endolymphatic shunt.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Endolymphatic shunt. 874.3820 Section 874.3820 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3820 Endolymphatic shunt....

  1. 21 CFR 874.3820 - Endolymphatic shunt.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Endolymphatic shunt. 874.3820 Section 874.3820 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3820 Endolymphatic shunt....

  2. 21 CFR 874.3820 - Endolymphatic shunt.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Endolymphatic shunt. 874.3820 Section 874.3820 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3820 Endolymphatic shunt....

  3. 21 CFR 874.3820 - Endolymphatic shunt.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3820 Endolymphatic shunt. (a) Identification. An endolymphatic shunt is a device that consists of a tube or sheet intended to be implanted to relieve the symptons of vertigo. The device permits the unrestricted flow of excess endolymph from...

  4. 21 CFR 874.3820 - Endolymphatic shunt.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3820 Endolymphatic shunt. (a) Identification. An endolymphatic shunt is a device that consists of a tube or sheet intended to be implanted to relieve the symptons of vertigo. The device permits the unrestricted flow of excess endolymph from...

  5. 49 CFR 234.229 - Shunting sensitivity.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Shunting sensitivity. 234.229 Section 234.229 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION..., Inspection, and Testing Maintenance Standards § 234.229 Shunting sensitivity. Each highway-rail...

  6. 49 CFR 236.56 - Shunting sensitivity.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Shunting sensitivity. 236.56 Section 236.56 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Track Circuits § 236.56 Shunting sensitivity. Each track circuit controlling home...

  7. 49 CFR 236.56 - Shunting sensitivity.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Shunting sensitivity. 236.56 Section 236.56 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Track Circuits § 236.56 Shunting sensitivity. Each track circuit controlling home...

  8. 49 CFR 234.229 - Shunting sensitivity.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Shunting sensitivity. 234.229 Section 234.229 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION..., Inspection, and Testing Maintenance Standards § 234.229 Shunting sensitivity. Each highway-rail...

  9. 49 CFR 236.56 - Shunting sensitivity.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Shunting sensitivity. 236.56 Section 236.56 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Track Circuits § 236.56 Shunting sensitivity. Each track circuit controlling home...

  10. 49 CFR 236.56 - Shunting sensitivity.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Shunting sensitivity. 236.56 Section 236.56 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Track Circuits § 236.56 Shunting sensitivity. Each track circuit controlling home...

  11. 49 CFR 236.56 - Shunting sensitivity.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Shunting sensitivity. 236.56 Section 236.56 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Track Circuits § 236.56 Shunting sensitivity. Each track circuit controlling home...

  12. Shunt failure caused by valve collapse.

    PubMed

    Lundar, T; Langmoen, I A; Hovind, K H

    1991-06-01

    Shunt failure due to collapse of the Mini-Holter valve was observed 13 times in 11 out of 179 children with an implanted Mini-Holter ventriculo-peritoneal (VP) or ventriculo-atrial (VA) shunt during a 10 year period. Intussusception of the proximal or distal end of the valve thus caused a shunt failure rate of 6% of the children in this series. Two children experienced this complication twice. All collapsed valves were part of a VP shunt system. Because of this experience use of the mini valve was abandoned and an adult Holter valve was implanted in children over the age of one month. Breakdown of this particular valve has not occurred in 102 children and two hundred adults with the adult Holter shunt system.

  13. Congenital Portosystemic Shunt: Our Experience

    PubMed Central

    Timpanaro, Tiziana; Passanisi, Stefano; Sauna, Alessandra; Trombatore, Claudia; Pennisi, Monica; Petrillo, Giuseppe; Smilari, Pierluigi; Greco, Filippo

    2015-01-01

    Introduction. Congenital portosystemic venous malformations are rare abnormalities in which the portal blood drains into a systemic vein and which are characterized by extreme clinical variability. Case Presentations. The authors present two case reports of a congenital extrahepatic portosystemic shunt (Type II). In the first patient, apparently nonspecific symptoms, such as headache and fatigue, proved to be secondary to hypoglycemic episodes related to the presence of a portosystemic shunt, later confirmed on imaging. During portal vein angiography, endovascular embolization of the portocaval fistula achieved occlusion of the anomalous venous tract. In the second patient, affected by Down's syndrome, the diagnosis of a portosystemic malformation was made by routine ultrasonography, performed to rule out concurrent congenital anomalies. Because of the absence of symptoms, we chose to observe this patient. Conclusions. These two case reports demonstrate the clinical heterogeneity of this malformation and the need for a multidisciplinary approach. As part of a proper workup, clinical evaluation must always be followed by radiographic diagnosis. PMID:25709849

  14. Distal ventriculoperitoneal shunt failure caused by silicone allergy. Case report.

    PubMed

    Hussain, Namath S; Wang, Paul P; James, Carol; Carson, Benjamin S; Avellino, Anthony M

    2005-03-01

    The placement of a ventriculoperitoneal (VP) shunt is the most common form of treatment for hydrocephalus. Although allergic reactions to the silicone in shunt hardware are very rare, the authors describe a case of silicone allergy causing multiple ventricular shunt revisions. A 24-year-old man, who had undergone multiple VP shunt revisions, presented with shunt malfunction caused by allergic reaction of the tissues surrounding the shunt tubing. The patient's existing silicone-based shunt was replaced with a new polyurethane system, including the proximal and distal catheters as well as the valve mechanism. Contrary to recommendations in previous studies of silicone shunt allergies, long-term immunosuppression was not initiated. The patient was followed up for more than 8 years without recurrence of an allergic reaction to the shunt. This outcome indicates that replacing the original silicone-based shunt system with a polyurethane-based system alone is sufficient in the treatment of a silicone shunt allergy.

  15. Transanal protrusion of a ventriculoperitoneal shunt catheter.

    PubMed

    Ozturk, Hulya; Is, Merih; Ozturk, Hayrettin; Kucuk, Adem; Dosoglu, Murat

    2012-11-01

    A two years old boy presented with a transanal protrusion of the ventriculoperitoneal (VP) shunt catheter. A VP shunt was inserted when the boy was six-month-old for congenital hydrocephalus. He was active and neurologically normal, with no signs of meningitis and peritoneal irritation. During laparotomy, the tube was seen entering the sigmoid colon, so the tube was cut at the point where it entered the sigmoid colon. The distal end of the protruding tube was pulled out from the anus. The sigmoid colon was repaired, and a delayed shunt revision was completed. The patient was discharged without abdominal and neurological deterioration.

  16. Transanal protrusion of a ventriculoperitoneal shunt catheter.

    PubMed

    Ozturk, Hulya; Is, Merih; Ozturk, Hayrettin; Kucuk, Adem; Dosoglu, Murat

    2012-11-01

    A two years old boy presented with a transanal protrusion of the ventriculoperitoneal (VP) shunt catheter. A VP shunt was inserted when the boy was six-month-old for congenital hydrocephalus. He was active and neurologically normal, with no signs of meningitis and peritoneal irritation. During laparotomy, the tube was seen entering the sigmoid colon, so the tube was cut at the point where it entered the sigmoid colon. The distal end of the protruding tube was pulled out from the anus. The sigmoid colon was repaired, and a delayed shunt revision was completed. The patient was discharged without abdominal and neurological deterioration. PMID:23146859

  17. Ventriculoperitoneal Shunt Peritoneal Catheter Knot Formation

    PubMed Central

    Ul-Haq, Anwar; Al-Otaibi, Faisal; Alshanafey, Saud; Sabbagh, Mohamed Diya; Al Shail, Essam

    2013-01-01

    The ventriculoperitoneal (VP) shunt is a common procedure in pediatric neurosurgery that carries a risk of complications at cranial and abdominal sites. We report on the case of a child with shunt infection and malfunction. The peritoneal catheter was tethered within the abdominal cavity, precluding its removal. Subsequently, laparoscopic exploration identified a knot at the distal end of the peritoneal catheter around the omentum. A new VP shunt was inserted after the infection was healed. This type of complication occurs rarely, so there are a limited number of case reports in the literature. This report is complemented by a literature review. PMID:24109528

  18. Ventriculo-peritoneal shunt performance under hyperbaric conditions.

    PubMed

    Huang, E T; Hardy, K R; Stubbs, J M; Lowe, R A; Thom, S R

    2000-01-01

    A novice scuba diver with an implanted ventriculo-peritoneal (VP) shunt inquired about the performance characteristics of his shunt while diving. A literature search revealed no information regarding shunt performance under hyperbaric conditions. The manufacturer could not certify that the shunt would function under pressure. Therefore, four VP shunts were tested according to the manufacturer's testing protocol at 1 and 4 atm abs in a multiplace hyperbaric chamber. The pressure (in mm of H2O) required to establish flow through the shunts was recorded. Trials at 1 atm abs (n = 12) and 4 atm abs (n = 12) show that all shunts performed within the pressure range specified by the manufacturer.

  19. Acute Shunt Malfunction Caused by Percutaneous Endoscopic Gastrostomy without Shunt Infection

    PubMed Central

    Choi, Jingyu; Ki, Seung Seog

    2014-01-01

    Percutaneous endoscopic gastrostomy tube placement is often performed in patients with a ventriculoperitoneal shunt and it has been accepted as a safe procedure. The authors report a case of a 50-year-old male who developed acute exacerbation of the hydrocephalus immediately after the percutaneous endoscopic gastrostomy tube placement without any signs of shunt infection, which has not been reported until now. After revision of the intraperitoneal shunt catheter, the sizes of the intracranial ventricles were normalized. PMID:25371790

  20. Syringosubarachnoid shunting using a myringotomy tube

    PubMed Central

    Leschke, Jack M.; Mumert, Michael L.; Kurpad, Shekar N.

    2016-01-01

    Background: Syringomyelia results from obstruction of cerebrospinal fluid (CSF) flow due to a multitude of causes. Often symptoms of pain, weakness, and sensory disturbance are progressive and require surgical treatment. We present here a rare technique for syringosubarachnoid shunting. Case Description: We present the case of a 38-year-old male who suffered a traumatic cervical spinal cord injury due to a motor vehicle accident. With progressive pain and motor decline, a magnetic resonance imaging was obtained and showed a new syrinx extending cervical multiple segments. A unique surgical procedure using a myringotomy tube to shunt CSF into the subarachnoid space was employed in this case. The patient's examination stabilized postoperatively, and at 2 months and 6 months follow-up visits, his strength and sensation continued to improve. Conclusion: We used a myringotomy tube for syringosubarachnoid shunting for the surgical management of a posttraumatic syrinx with good results. This technique minimizes suturing and may minimize shunt-related complications. PMID:26862456

  1. Optimal shunt compensators at nonsinusoidal busbars

    SciTech Connect

    El-Amin, I.M.; Duffuaa, S.O.; Bawah, A.U.

    1995-05-01

    A model for determining an optimal shunt capacitor value at nonsinusoidal busbars combining three basic criteria--maximizing the power factor, minimizing the line losses, and maximizing the transmission efficiency is developed. The choice of the capacitor value is constrained by the values that may cause resonance. This model was solved employing the penalty function approach and the golden Section Search algorithm for solving the linear load case. Furthermore nonlinear loads operating under nonsinusoidal conditions were investigated. The model for the nonlinear load is a two variable problem in L (inductor) and C (capacitor). The Direct Search Polytope algorithm is used. The solution of this model yields an optimal shunt LC compensator for the nonlinear load. However, since there are limitations on the practical values of shunt capacitor, a discretizing approach making use of standard shunt capacitor values is employed to guarantee a solution that can be implemented.

  2. Aneurysmal portosystemic venous shunt: a case report.

    PubMed

    Bodner, G; Glück, A; Springer, P; König, P; Perkmann, R

    1999-10-01

    A case of an aneurysmal portosystemic venous shunt detected by colour Doppler ultrasound (CDUS) is presented. A young female patient complained of postprandial fatigue and had paroxysmal tachycardia. A direct vascular communication between right portal vein and right hepatic vein was found at CDUS and confirmed by direct portal angiogram. Using detachable coils a complete occlusion of the intrahepatic shunt was obtained. Reports from the literature regarding portovenous aneurysms are reviewed.

  3. Cell shunt resistance and photovoltaic module performance

    SciTech Connect

    McMahon, T.J.; Basso, T.S.; Rummel, S.R.

    1996-05-01

    Shunt resistance of cells in photovoltaic modules can affect module power output and could indicate flawed manufacturing processes and reliability problems. The authors describe a two-terminal diagnostic method to directly measure the shunt resistance of individual cells in a series-connected module non-intrusively, without deencapsulation. Peak power efficiency vs. light intensity was measured on a 12-cell, series-connected, single crystalline module having relatively high cell shunt resistances. The module was remeasured with 0.5-, 1-, and 2-ohm resistors attached across each cell to simulate shunt resistances of several emerging technologies. Peak power efficiencies decreased dramatically at lower light levels. Using the PSpice circuit simulator, the authors verified that cell shunt and series resistances can indeed be responsible for the observed peak power efficiency vs. intensity behavior. The authors discuss the effect of basic cell diode parameters, i.e., shunt resistance, series resistance, and recombination losses, on PV module performance as a function of light intensity.

  4. Ventriculoperitoneal shunt in cryptococcal meningitis with hydrocephalus.

    PubMed

    Tang, L M

    1990-05-01

    Fourteen patients with cryptococcal meningitis were reviewed. All patients had a ventriculoperitoneal shunt for hydrocephalus. Early recognitions and prompt relief of hydrocephalus were useful for eight patients who showed rapid deterioration of consciousness or signs of cerebral herniation. There was no surgical response in four patients who had had weeks of confusion or mental change. It seems, therefore, that the duration of disturbance of consciousness or change of mentality before shunting is critical in determination of the outcome of the treatment. Ventricular shunting was effective in relieving papilledema in five patients. However, the surgery did not prevent the development of papilledema to optic atrophy and subsequent blindness in two patients. Hence, in addition to hydrocephalus with increased intracranial pressure, conditions such as direct invasion of the optic pathways by Cryptococcus neoformans or optochiasmatic arachnoiditis may be responsible for the visual failure. Ventricular shunting was also helpful in restoring paraparesis in one patient. Of the cerebrospinal fluid determinations, low protein concentration was a favorable indicator for surgery. Of the seven patients who received the surgical procedure before the start of antifungal therapy, four showed a significant improvement despite active infection of the central nervous system. None of the seven patients deteriorated because of the surgical operation. Thus, active stage of cryptococcal meningitis does not contraindicate the necessity of shunting, and premedication with antifungal drugs is unnecessary. Also, no shunt-related morbidity and mortality was seen in this study.

  5. Simulation model for port shunting yards

    NASA Astrophysics Data System (ADS)

    Rusca, A.; Popa, M.; Rosca, E.; Rosca, M.; Dragu, V.; Rusca, F.

    2016-08-01

    Sea ports are important nodes in the supply chain, joining two high capacity transport modes: rail and maritime transport. The huge cargo flows transiting port requires high capacity construction and installation such as berths, large capacity cranes, respectively shunting yards. However, the port shunting yards specificity raises several problems such as: limited access since these are terminus stations for rail network, the in-output of large transit flows of cargo relatively to the scarcity of the departure/arrival of a ship, as well as limited land availability for implementing solutions to serve these flows. It is necessary to identify technological solutions that lead to an answer to these problems. The paper proposed a simulation model developed with ARENA computer simulation software suitable for shunting yards which serve sea ports with access to the rail network. Are investigates the principal aspects of shunting yards and adequate measures to increase their transit capacity. The operation capacity for shunting yards sub-system is assessed taking in consideration the required operating standards and the measure of performance (e.g. waiting time for freight wagons, number of railway line in station, storage area, etc.) of the railway station are computed. The conclusion and results, drawn from simulation, help transports and logistics specialists to test the proposals for improving the port management.

  6. Ventricular gallbladder shunts: an alternative procedure in hydrocephalus.

    PubMed

    West, K W; Turner, M K; Vane, D W; Boaz, J; Kalsbeck, J; Grosfeld, J L

    1987-07-01

    Hydrocephalus is a frequently encountered problem in infancy and is most commonly treated by placement of ventriculoperionteal (VP) or ventriculoatrial (VA) shunts. Other sites for insertion of the distal shunt have included the stomach, ureter, and fallopian tube. This report describes an experience with ventricular gallbladder shunts (VGB) in 25 children performed from 1970 to 1985. There were 13 girls and 12 boys ranging in age from 6 months to 16 years. Diagnosis included meningomyelocoele (7), congenital hydrocephalus (7), postmeningitic complications (5), intracranial tumor (4), and intraventricular hemorrhage (2). Indications for operation included VP shunt infection (15), massive ascites following VP shunt (3), VA shunt infection (4), and distal shunt malfunction due to fibrinous adhesions or cysts (secondary to infection; (3). Three patients had early shunt failure due to proximal obstruction (2) and gallbladder atony (1). Shunt revision was required in two and the atony was successfully treated with cholecystokinin in one. Fourteen shunts remain in place, two patients have been lost to follow-up, and three children died from unrelated causes. Seventy percent of the 20 patients available for long-term follow-up have functional shunts in place. The VGB shunt procedure remains an attractive alternative for patients with hydrocephalus in whom intraperitoneal and intravascular shunts are no longer feasible.

  7. Delayed Intracerebral Hemorrhage Secondary to Ventriculoperitoneal Shunt

    PubMed Central

    Ma, Li; Chen, Yi-Li; Yang, Shu-Xu; Wang, Yi-Rong

    2015-01-01

    Abstract The ventriculoperitoneal (VP) shunt is a routine procedure for cerebrospinal fluid (CSF) diversion, and is associated with many complications. A delayed hemorrhage after the VP shunt surgery, however, is quite rare. In this study, we report a case involving late-onset hemorrhage. The 67-year-old male patient with a history of head trauma and brain surgery underwent a VP shunt placement for hydrocephalus. The surgery course was uneventful and no bleeding was revealed in the first computed tomographic (CT) scan after the procedure. However, a massive intraparenchymal and intraventricular hemorrhage occurred 8 h following adjustment of the valve system on the 8th day after surgery. Erosion of the vasculature by catheter cannulation and a sudden reduction of CSF pressure after downregulation of the valve could be one of the possible causes of the intracerebral hemorrhage (ICH). PMID:26632700

  8. Radionuclide demonstration of intrapulmonary shunting in cirrhosis

    SciTech Connect

    Bank, E.R.; Thrall, J.H.; Dantzker, D.R.

    1983-05-01

    The association of hepatic cirrhosis and severe arterial hypoxemia has been well described. Although alterations in ventilatory function may partially account for the hypoxemia, the principal mechanism is thought to be a microangiopathic change in the pulmonary vasculature resulting in intrapulmonary arteriovenous shunting with resultant systemic desaturation. Whole-body radionuclide scans with technetium-99m macroaggregated albumin labeling have been diagnostic of right-to-left shunting by their demonstration of tracer accumulation within the extrapulmonary circulation. A case of severe pulmonary arteriovenous shunting in an alcoholic patient in whom hepatic disease had not been of apparent clinical significance before radionuclide scanning is reported. He did not have cuntaeous angiomata as have all other patients with alcoholic cirrhosis and hypoxemia.

  9. Radionuclide demonstration of intrapulmonary shunting in cirrhosis

    SciTech Connect

    Bank, E.R.; Thrall, J.H.; Dantzker, D.R.

    1983-05-01

    The association of hepatic cirrhosis and severe arterial hypoxemia has been well described. Although alterations in ventilatory function may partially account for the hypoxemia, the principal mechanism is thought to be a microangiopathic change in the pulmonary arteriovenous shunting with resultant systemic desaturation. Whole-body radionuclide scans with technetium-99m macroaggrregated albumin (/sup 99m/Tc MAA) labeling have been diagnostic of right-to-left shunting by their demonstration of tracer accumulation within the extrapulmonary circulation. A case of severe pulmonary arteriovenous shunting in an alcoholic patient in whom hepatic disease had not been of apparent clinical significance before radionuclide scanning is reported. He did not have cutaneous angiomata as have all other patients with alcoholic cirrhosis and hypoxemia.

  10. Seizures in relation to shunt dysfunction in children with meningomyelocele.

    PubMed

    Hack, C H; Enrile, B G; Donat, J F; Kosnik, E

    1990-01-01

    To determine whether seizures are a reliable sign of increased intraventricular pressure in children with shunt-dependent hydrocephalus and meningomyelocele, we performed a retrospective chart review of 346 patients with meningomyelocele and shunt-dependent hydrocephalus. Fifty-one patients had seizures. Seizure episodes were investigated to determine whether they were temporally associated with shunt dysfunction. Episodes of actual or presumed shunt dysfunction were analyzed as to presenting symptoms, ventriculogram, computed tomography scan, and shunt film results. These 51 patients had 129 admissions for possible shunt dysfunction. One hundred one admissions were due to increased intraventricular pressure; nine (9%) of these, had a seizure as one of the presenting symptoms. All of the nine episodes had other common presenting symptoms of shunt dysfunction, such as headache, vomiting, lethargy, or respiratory compromise. We conclude that seizures alone are an inadequate predictor of shunt dysfunction in children with meningomyelocele, but can be seen as one of the presenting symptoms.

  11. [Temporary vascular shunt technique for resource scarce environments].

    PubMed

    Ouattara, N; Mlynski, A; Pierret, C

    2011-10-01

    The purpose of this report is to describe a simple and reproducible technique for temporary vascular shunting. This technique is appropriate only for exceptional situations involving scant resource availability. It is not intended to replace conventional vascular shunting techniques.

  12. Ventricular shunt infections: immunopathogenesis and clinical management.

    PubMed

    Gutierrez-Murgas, Yenis; Snowden, Jessica N

    2014-11-15

    Ventricular shunts are the most common neurosurgical procedure performed in the United States. This hydrocephalus treatment is often complicated by infection of the device with biofilm-forming bacteria. In this review, we discuss the pathogenesis of shunt infection, as well as the implications of the biofilm formation on treatment and prevention of these infections. Many questions remain, including the contribution of glia and the impact of inflammation on developmental outcomes following infection. Immune responses within the CNS must be carefully regulated to contain infection while minimizing bystander damage; further study is needed to design optimal treatment strategies for these patients.

  13. Recovery from confabulation after normotensive hydrocephalus shunting.

    PubMed

    Dalla Barba, Gianfranco; Barbera, Claudia; Brazzarola, Marta; Marangoni, Sara

    2016-02-01

    Confabulation, the production of statements and actions that are unintentionally incongruous to the subject's history, background, present and future situation, is observed in several conditions affecting the nervous system, but it has never been described in normotensive hydrocephalus. In this article we report on a patient with normotensive hydrocephalus who suffered from an amnesic-confabulatory syndrome. After hydrocephalus shunting, both amnesia and confabulation cleared up abruptly. We discuss this finding in terms of a possible disconnection of the hippocampus, due to transitory white matter damage, which may have recovered after hydrocephalus shunting.

  14. Recurrent Breast Cancer in a Patient with a Ventriculoperitoneal Shunt

    PubMed Central

    Copeland-Halperin, Libby R.; Cohen, Robert A.

    2015-01-01

    We report a case of a patient with recurrent infiltrating ductal carcinoma of the breast encasing a ventriculoperitoneal shunt. We also review the current literature regarding reports of breast malignancy around a ventriculoperitoneal shunt, as well as the potential relevance of such shunts to the preoperative evaluation and management of patients with breast cancer. PMID:25648450

  15. Emergency department management of ventriculoperitoneal cerebrospinal fluid shunts.

    PubMed

    Madsen, M A

    1986-11-01

    Emergency physicians must be familiar with VP shunts in order to recognize critical complications associated with these devices. Knowledge of the major types of shunt devices commonly used and the mechanics of those devices allows emergency physicians to evaluate patients with shunts in an orderly manner.

  16. 49 CFR 236.57 - Shunt and fouling wires.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Shunt and fouling wires. 236.57 Section 236.57...: All Systems Track Circuits § 236.57 Shunt and fouling wires. (a) Except as provided in paragraph (b) of this section, shunt wires and fouling wires hereafter installed or replaced shall consist of...

  17. 49 CFR 236.104 - Shunt fouling circuit.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Shunt fouling circuit. 236.104 Section 236.104 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Inspections and Tests; All Systems § 236.104 Shunt fouling circuit. Shunt fouling...

  18. 49 CFR 236.725 - Circuit, switch shunting.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Circuit, switch shunting. 236.725 Section 236.725 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Circuit, switch shunting. A shunting circuit which is closed through contacts of a switch...

  19. 49 CFR 236.104 - Shunt fouling circuit.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Shunt fouling circuit. 236.104 Section 236.104 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Inspections and Tests; All Systems § 236.104 Shunt fouling circuit. Shunt fouling...

  20. 49 CFR 236.60 - Switch shunting circuit; use restricted.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Switch shunting circuit; use restricted. 236.60... Instructions: All Systems Track Circuits § 236.60 Switch shunting circuit; use restricted. Switch shunting circuit shall not be hereafter installed, except where tract or control circuit is opened by the...

  1. 49 CFR 236.725 - Circuit, switch shunting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Circuit, switch shunting. 236.725 Section 236.725 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Circuit, switch shunting. A shunting circuit which is closed through contacts of a switch...

  2. 49 CFR 236.104 - Shunt fouling circuit.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Shunt fouling circuit. 236.104 Section 236.104 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Inspections and Tests; All Systems § 236.104 Shunt fouling circuit. Shunt fouling...

  3. 49 CFR 236.60 - Switch shunting circuit; use restricted.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Switch shunting circuit; use restricted. 236.60... Instructions: All Systems Track Circuits § 236.60 Switch shunting circuit; use restricted. Switch shunting circuit shall not be hereafter installed, except where tract or control circuit is opened by the...

  4. 49 CFR 236.60 - Switch shunting circuit; use restricted.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Switch shunting circuit; use restricted. 236.60... Instructions: All Systems Track Circuits § 236.60 Switch shunting circuit; use restricted. Switch shunting circuit shall not be hereafter installed, except where tract or control circuit is opened by the...

  5. 49 CFR 236.725 - Circuit, switch shunting.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Circuit, switch shunting. 236.725 Section 236.725 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Circuit, switch shunting. A shunting circuit which is closed through contacts of a switch...

  6. [Intraabdominal metastasis of cerebellar medulloblastoma through ventriculoperitoneal shunt].

    PubMed

    Carrasco Torrents, R; Sancho, M A; Juliá, V; Montaner, A; Costa, J M; Morales, L

    2001-01-01

    We present a 6-year-old girl with cerebellar medulloblastoma causing obstructive hydrocephalus that was treated by ventriculoperitoneal shunting. The patient subsequently underwent surgical excision of the tumor followed by adjuvant craniospinal radiotherapy. Nine months after shunting, multiple intraabdominal metastatic lesions were found. Although the risk is low, ventriculoperitoneal shunting may facilitate the spread of malignant cells.

  7. 49 CFR 236.60 - Switch shunting circuit; use restricted.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Switch shunting circuit; use restricted. 236.60... Instructions: All Systems Track Circuits § 236.60 Switch shunting circuit; use restricted. Switch shunting circuit shall not be hereafter installed, except where tract or control circuit is opened by the...

  8. 49 CFR 236.104 - Shunt fouling circuit.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Shunt fouling circuit. 236.104 Section 236.104 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION...: All Systems Inspections and Tests; All Systems § 236.104 Shunt fouling circuit. Shunt fouling...

  9. 49 CFR 236.725 - Circuit, switch shunting.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Circuit, switch shunting. 236.725 Section 236.725 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Circuit, switch shunting. A shunting circuit which is closed through contacts of a switch...

  10. Direct intrahepatic portacaval shunt: An experimental study

    PubMed Central

    Luo, Jian-Jun; Yan, Zhi-Ping; Zhou, Kang-Rong; Qian, Sheng

    2003-01-01

    AIM: To determine the feasibility of creating direct intrahepatic portacaval shunt (DIPS) in swine with puncture under sonographic guidance. METHODS: DIPS was created in 10 domestic swine under sonographic guidance. Liver function, blood ammonia level and portosystemic gradient (PSG) were compared before and after the procedure. Patency of shunt was followed by portography every 7 d after DIPS. RESULTS: DIPS was successfully established in all 10 swine without any complications. One day after procedure the alanine aminotransferase (ALT), aspartate aminotransferase (AST), and blood ammonia level (BAL) of swine rose from 5.40 ± 0.69, 16.00 ± 0.79 and 35.66 ± 4.10 to 34.20 ± 3.46, 59.70 ± 2.22 and 66.94 ± 3.44 respectively (P < 0.05). The PSG decreased from 0.59 ± 0.20 kPa to 0.24 ± 0.11 kPa after DIPS (P < 0.05). The shunt of 10 swine was kept patent from 7-28 d (median patency time was 14 d). CONCLUSION: This initial experience demonstrated that creating intrahepatic portacaval shunt from retrohepatic segment of IVC to portal vein with puncture under sonographic guidance in swine is safe and feasible. Further studies are necessary to perform DIPS in cirrhosis patients. PMID:12532459

  11. Treatment of syringomyelia with a syringosubarachnoid shunt.

    PubMed

    Tator, C H; Briceno, C

    1988-02-01

    The surgical results in 40 patients with syringomyelia, treated with a syringosubarachnoid shunt or other procedures are reviewed. The principal indication for surgery was that of significant neurological deterioration. There were 12 patients with idiopathic syringomyelia without tonsillar ectopia, 12 with an associated Chiari malformation, 11 with post-traumatic syringomyelia and five patients with spinal arachnoiditis. There were 38 syringosubarachnoid shunts performed in 35 patients, and an excellent or good result was achieved in 26 patients (74.3%). In terms of the type of syringomyelia, the best results were obtained in the idiopathic group without tonsillar ectopia and in the post-traumatic group. A short duration of pre-operative symptoms favoured a better outcome, and in our opinion, early surgical treatment is indicated for all patients with neurological deterioration. All eight patients in whom a posterior fossa decompression was performed as the initial surgical procedure required a second operation, either a syringosubarachnoid or syringoperitoneal shunt to achieve neurological improvement or stabilization. Thus, the syringosubarachnoid shunt is an effective therapeutic modality for patients with syringomyelia, particularly for the idiopathic and post-traumatic groups. More than one surgical procedure may be required to achieve cessation of deterioration. Overall, excellent or good results were achieved in 29 (72.5%) of the 40 patients.

  12. 49 CFR 234.229 - Shunting sensitivity.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Shunting sensitivity. 234.229 Section 234.229 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... sensitivity. Each highway-rail grade crossing train detection circuit shall detect the application of a...

  13. 49 CFR 234.229 - Shunting sensitivity.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Shunting sensitivity. 234.229 Section 234.229 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... sensitivity. Each highway-rail grade crossing train detection circuit shall detect the application of a...

  14. 49 CFR 234.229 - Shunting sensitivity.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Shunting sensitivity. 234.229 Section 234.229 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... sensitivity. Each highway-rail grade crossing train detection circuit shall detect the application of a...

  15. Episodic ventriculomegaly due to hypernatremia mimicking shunt malfunction: case report.

    PubMed

    Jernigan, Sarah C; Stone, Scellig S D; Aronson, Joshua P; Putman, Melissa; Proctor, Mark R

    2015-10-01

    Patients with shunted hydrocephalus presenting with altered mental status and ventriculomegaly are generally considered to be in shunt failure requiring surgical treatment. The authors describe a case of shunted hydrocephalus secondary to a disseminated neuroectodermal tumor in a pediatric patient in whom rapid fluctuations in sodium levels due to diabetes insipidus repeatedly led to significant changes in ventricle size, with invasively confirmed normal shunt function and low intracranial pressure. This clinical picture exactly mimics shunt malfunction, requires urgent nonsurgical therapy, and underscores the importance of considering serum osmolar abnormalities in the differential diagnosis for ventriculomegaly.

  16. [Cerebrospinal fluid shunts for hydrocephalus and related disorders].

    PubMed

    Ito, Masaki; Houkin, Kiyohiro; Saito, Hisayasu; Shimbo, Daisuke; Motegi, Hiroaki; Kawabori, Masahito; Miyamoto, Michiyuki; Yamauchi, Tomohiro

    2012-10-01

    Cerebrospinal fluid (CSF) shunts are commonly employed to treat patients with hydrocephalus. A large number of papers have been published focusing on complications and failures of CSF shunts. However, there appears to be a paucity of knowledge comprehensively covering both common complications and rare ones. In this systematic review, we surveyed articles about surgical complications of CSF shunts as comprehensively as possible. Quantitative analysis was performed to determine the frequency of well-known complications, mortality and revision rates of CSF shunts. Furthermore, rare complications of CSF shunts have also been reviewed.

  17. Platypnea-Orthodeoxia Syndrome: To Shunt or Not to Shunt, That is the Question.

    PubMed

    Klein, Michael R; Kiefer, Todd L; Velazquez, Eric J

    2016-06-01

    Platypnea-orthodeoxia syndrome is a rare disease defined by dyspnea and deoxygenation, induced by an upright position, and relieved by recumbency. Causes include shunting through a patent foramen ovale and pulmonary arteriovenous malformations. A 79-year-old woman experienced 2 syncopal episodes at rest and presented at another hospital. In the emergency department, she was hypoxic, needing 6 L/min of oxygen. Her chest radiograph showed nothing unusual. Transthoracic echocardiograms with saline microcavitation evaluation were mildly positive early after agitated-saline administration, suggesting intracardiac shunting. She was then transferred to our center. Right-sided heart catheterization revealed no oximetric evidence of intracardiac shunting while the patient was supine and had a low right atrial pressure. However, her oxygen saturation dropped to 78% when she sat up. Repeat transthoracic echocardiography while sitting revealed a dramatically positive early saline microcavitation-uptake into the left side of the heart. Transesophageal echocardiograms showed a patent foramen ovale, with right-to-left shunting highly dependent upon body position. The patient underwent successful percutaneous patent foramen ovale closure, and her oxygen supplementation was suspended. In patients with unexplained or transient hypoxemia in which a cardiac cause is suspected, it is important to evaluate shunting in both the recumbent and upright positions. In this syndrome, elevated right atrial pressure is not necessary for significant right-to-left shunting. Percutaneous closure, if feasible, is first-line therapy in these patients.

  18. Platypnea-Orthodeoxia Syndrome: To Shunt or Not to Shunt, That is the Question

    PubMed Central

    Kiefer, Todd L.; Velazquez, Eric J.

    2016-01-01

    Platypnea-orthodeoxia syndrome is a rare disease defined by dyspnea and deoxygenation, induced by an upright position, and relieved by recumbency. Causes include shunting through a patent foramen ovale and pulmonary arteriovenous malformations. A 79-year-old woman experienced 2 syncopal episodes at rest and presented at another hospital. In the emergency department, she was hypoxic, needing 6 L/min of oxygen. Her chest radiograph showed nothing unusual. Transthoracic echocardiograms with saline microcavitation evaluation were mildly positive early after agitated-saline administration, suggesting intracardiac shunting. She was then transferred to our center. Right-sided heart catheterization revealed no oximetric evidence of intracardiac shunting while the patient was supine and had a low right atrial pressure. However, her oxygen saturation dropped to 78% when she sat up. Repeat transthoracic echocardiography while sitting revealed a dramatically positive early saline microcavitation-uptake into the left side of the heart. Transesophageal echocardiograms showed a patent foramen ovale, with right-to-left shunting highly dependent upon body position. The patient underwent successful percutaneous patent foramen ovale closure, and her oxygen supplementation was suspended. In patients with unexplained or transient hypoxemia in which a cardiac cause is suspected, it is important to evaluate shunting in both the recumbent and upright positions. In this syndrome, elevated right atrial pressure is not necessary for significant right-to-left shunting. Percutaneous closure, if feasible, is first-line therapy in these patients. PMID:27303248

  19. Platypnea-Orthodeoxia Syndrome: To Shunt or Not to Shunt, That is the Question.

    PubMed

    Klein, Michael R; Kiefer, Todd L; Velazquez, Eric J

    2016-06-01

    Platypnea-orthodeoxia syndrome is a rare disease defined by dyspnea and deoxygenation, induced by an upright position, and relieved by recumbency. Causes include shunting through a patent foramen ovale and pulmonary arteriovenous malformations. A 79-year-old woman experienced 2 syncopal episodes at rest and presented at another hospital. In the emergency department, she was hypoxic, needing 6 L/min of oxygen. Her chest radiograph showed nothing unusual. Transthoracic echocardiograms with saline microcavitation evaluation were mildly positive early after agitated-saline administration, suggesting intracardiac shunting. She was then transferred to our center. Right-sided heart catheterization revealed no oximetric evidence of intracardiac shunting while the patient was supine and had a low right atrial pressure. However, her oxygen saturation dropped to 78% when she sat up. Repeat transthoracic echocardiography while sitting revealed a dramatically positive early saline microcavitation-uptake into the left side of the heart. Transesophageal echocardiograms showed a patent foramen ovale, with right-to-left shunting highly dependent upon body position. The patient underwent successful percutaneous patent foramen ovale closure, and her oxygen supplementation was suspended. In patients with unexplained or transient hypoxemia in which a cardiac cause is suspected, it is important to evaluate shunting in both the recumbent and upright positions. In this syndrome, elevated right atrial pressure is not necessary for significant right-to-left shunting. Percutaneous closure, if feasible, is first-line therapy in these patients. PMID:27303248

  20. Premature fractures of platinum-cured Silastic shunts.

    PubMed

    Ramsey, D B; Chadduck, W M

    1992-10-01

    Experience with one unitized ventriculoperitoneal (VP) shunt system has disclosed an unacceptably high rate of premature distal shunt tube fracturing. From March, 1986, to February, 1989, 114 new or replacement unitized VP shunts were placed; the patients were followed through November, 1991. Twenty-two (19.3%) returned with peritoneal limb fractures, with a mean time from shunt implantation to fracture of 31.5 +/- 11.3 months (range 15-62 months). All shunts broke in the neck 1.1-11.2 cm below the valve. Of the 22 cases, there were no instances of infection, previous peritoneal limb revisions, or recognizable iatrogenic shunt injury at placement. These fractures also occurred earlier than the usual time expected for biodegradation of shunt tubing. The Silastic tubing in all of these shunts had been manufactured using a more recent platinum-curing process. This tubing has decreased elastance and is more brittle than tubing cured with the previously used dichlorobenzoyl peroxide (DCBP) catalyst. Our studies suggest that the premature shunt tube fractures were related to changes in physical characteristics of the platinum-cured Silastic tubing. Therefore, the DCBP-cured Silastic is to be considered preferable for shunting products. Neurosurgeons are asked to report recurring patterns of shunt system failure.

  1. Intraparenchymal pericatheter cyst following disconnection of ventriculoperitoneal shunt system.

    PubMed

    Balasubramaniam, S; Tyagi, D K; Sawant, H V

    2013-01-01

    Ventriculoperitoneal (VP) shunt is one of the most commonly performed procedures in neurosurgery, but it is also the procedure, which is most prone to complications. Spread of cerebrospinal fluid (CSF) into the brain parenchyma is a rare complication of VP shunt and can take the form of CSF edema or a porencephalic cyst. We describe a case of a 1½-year-old child who presented to us with seizures. Computed tomography scan revealed pericatheter porencephalic cyst. Surgical exploration revealed a disconnected VP shunt system. Patient was neurologically observed after shunt extraction. He was seizure free and radiological follow-up showed resolution of cyst. Ours is the first case to document the presence of pericatheter cyst following complete disconnection of shunt system. Though shunt revision is the accepted treatment modality, careful neurological observation can be done after shunt removal especially in asymptomatic cases with compensated hydrocephalus.

  2. Passively Shunted Piezoelectric Damping of Centrifugally-Loaded Plates

    NASA Technical Reports Server (NTRS)

    Duffy, Kirsten P.; Provenza, Andrew J.; Trudell, Jeffrey J.; Min, James B.

    2009-01-01

    Researchers at NASA Glenn Research Center have been investigating shunted piezoelectric circuits as potential damping treatments for turbomachinery rotor blades. This effort seeks to determine the effects of centrifugal loading on passively-shunted piezoelectric - damped plates. Passive shunt circuit parameters are optimized for the plate's third bending mode. Tests are performed both non-spinning and in the Dynamic Spin Facility to verify the analysis, and to determine the effectiveness of the damping under centrifugal loading. Results show that a resistive shunt circuit will reduce resonant vibration for this configuration. However, a tuned shunt circuit will be required to achieve the desired damping level. The analysis and testing address several issues with passive shunt circuit implementation in a rotating system, including piezoelectric material integrity under centrifugal loading, shunt circuit implementation, and tip mode damping.

  3. Shunt tube problems due to placement of valves on the chest wall--three case reports.

    PubMed

    Tsurushima, H; Harakuni, T; Saito, A; Hyodo, A; Yoshii, Y

    2000-06-01

    Programmable valves are often used for ventriculoperitoneal (VP) shunts with the shunt valve positioned on the chest wall. Three cases of shunt problems occurred due to placement of the valve on the chest wall. A 43-year-old male was treated with a VP shunt, and suffered shunt malfunction due to dislocation of the ventricular tube. A 21-year-old male was treated with a VP shunt, and suffered shunt malfunction due to disconnection of the shunt tube. A 4-day-old female neonate was treated with a VP shunt, and suffered migration of the shunt valve. The shunt system has two anchor sites on the head and chest wall, with the neck between the two anchor sites. High tension is sometimes caused in the shunt tube between the two points due to movement of the neck or growth, and may induce such dislocation and disconnection of the shunt tube. We recommend a longer shunt tube in such cases.

  4. Free floating ventricular shunt catheter between lateral ventricles: a case report of an unusual ventriculoperitoneal shunt complication.

    PubMed

    Erol, Fatih Serhat; Cakin, Hakan; Ozturk, Sait; Donmez, Osman; Kaplan, Metin

    2013-01-01

    Ventriculoperitoneal (VP) shunt proximal tip disconnection is rarely seen as a shunt complication. Shunt dysfunction and hydrocephaly can develop due to this disconnection. Presented here is a case of a disconnection of the ventricular catheter from the shunt valve, which passed between both lateral ventricles by free floating in the brain CT. The patient was operated on for hydrocephaly. The dysfunctional shunt valve and peritoneal catheter were removed and a new VP shunt system was implemented. Although some publications report that the ventricular catheter can be disconnected from the shunt valve, can adhere to the intraventricular structures, and can be a source of infection, no studies similar to the current case were found in the literature reporting a free floating ventricular catheter between the lateral ventricles.

  5. Fatal cardiopulmonary complications in children treated with ventriculoatrial shunts.

    PubMed

    Lundar, T; Langmoen, I A; Hovind, K H

    1991-08-01

    During the years from 1965 to 1986, 716 children underwent a total of 2065 shunt procedures in our department. Of these, 1298 were ventriculoatrial (VA). Until 1979, Pudenz VA shunts were almost exclusively used as the primary procedure as well as in revisions. Since 1980, mini-Holter VA shunts have been implanted as a second choice, usually in cases with repeated distal failure in ventriculoperitoneal (VP) shunts. Observation time for children with VA shunts is therefore from 10 to 23 years for the great majority. The cumulative death rate for all patients is 24% (175/716), 9% (64/716) being tumor patients who eventually died as a result of their neoplasm. Most of the other deaths were caused by shunt infection or occurred in a group of children where shunts had been implanted for palliative reasons and where follow-up was only sporadic. Among the 450 children with VA shunts, 15 fatal complications occurred that were directly related to the atrial catheter, resulting in an accumulated incidence of 3% of such serious side effects from VA shunting. Three of these 15 fatal cases presented with nonspecific signs of cardiopulmonary failure following 10-21 years' shunting, and they died from irreversible pulmonary hypertension within a few months. A fourth case of late cor pulmonale has done unexpectedly well and has improved considerably while receiving anticoagulant therapy for over a period of 3 years.

  6. Who Needs a Revision? 20 Years of Cambridge Shunt Lab.

    PubMed

    Czosnyka, Zofia; Czosnyka, Marek; Pickard, John D; Chari, Aswin

    2016-01-01

    Shunt testing independent of manufacturers provides knowledge that can significantly improve the management of patients with hydrocephalus. The Cambridge Shunt Evaluation Laboratory was created 20 years ago. Thanks to financial support from the Department of Health (1993-1998), all shunts in use in the UK were systematically evaluated, with "blue reports" being published. Later new devices were tested as they appeared in public domain.Twenty-six models have been evaluated. The majority of the valves had a non-physiologically low hydrodynamic resistance that may result in over-drainage, both related to posture and during nocturnal cerebral vasogenic waves. A long distal catheter increases the resistance of these valves by 100-200 %. Drainage through valves without a siphon-preventing mechanism is very sensitive to body posture. Shunts with siphon-preventing accessories offer a reasonable resistance to negative outlet pressure. Bench parameters were used to test shunt performance in vivo using infusion tests. A criterion for correctly performing a shunt procedure was established. Pressure measured in the shunt prechamber during the plateau phase of infusion should not remain more than 5 mmHg above the le shunt's operating pressure plus hydrodynamic resistance of the valve multiplied by the infusion rate. "Critical levels" for every shunt and every performance level have been used in the shunt testing wizard of ICM+ software.

  7. Laparoscopically assisted ventriculoperitoneal shunt placement: a prospective randomized controlled trial.

    PubMed

    Schucht, Philippe; Banz, Vanessa; Trochsler, Markus; Iff, Samuel; Krähenbühl, Anna Katharina; Reinert, Michael; Beck, Jürgen; Raabe, Andreas; Candinas, Daniel; Kuhlen, Dominique; Mariani, Luigi

    2015-05-01

    OBJECT In ventriculoperitoneal (VP) shunt surgery, laparoscopic assistance can be used for placement of the peritoneal catheter. Until now, the efficacy of laparoscopic shunt placement has been investigated only in retrospective and nonrandomized prospective studies, which have reported decreased distal shunt dysfunction rates in patients undergoing laparascopic placement compared with mini-laparotomy cohorts. In this randomized controlled trial the authors compared rates of shunt failure in patients who underwent laparoscopic surgery for peritoneal catheter placement with rates in patients who underwent traditional mini-laparotomy. METHODS One hundred twenty patients scheduled for VP shunt surgery were randomized to laparoscopic surgery or mini-laparotomy for insertion of the peritoneal catheter. The primary endpoint was the rate of overall shunt complication or failure within the first 12 months after surgery. Secondary endpoints were distal shunt failure, overall complication/ failure, duration of surgery and hospitalization, and morbidity. RESULTS The overall shunt complication/failure rate was 15% (9 of 60 cases) in the laparoscopic group and 18.3% (11 of 60 cases) in the mini-laparotomy group (p = 0.404). Patients in the laparoscopic group had no distal shunt failures; in contrast, 5 (8%) of 60 patients in the mini-laparotomy group experienced distal shunt failure (p = 0.029). Intraoperative complications occurred in 2 patients (both in the laparoscopic group), and abdominal pain led to catheter removal in 1 patient per group. Infections occurred in 1 patient in the laparoscopic group and 3 in the mini-laparotomy group. The mean durations of surgery and hospitalization were similar in the 2 groups. CONCLUSIONS While overall shunt failure rates were similar in the 2 groups, the use of laparoscopic shunt placement significantly reduced the rate of distal shunt failure compared with mini-laparotomy.

  8. Incisional Hernia Following Ventriculoperitoneal Shunt Positioning

    PubMed Central

    Bonatti, Matteo; Vezzali, Norberto; Frena, Antonio; Bonatti, Giampietro

    2016-01-01

    Incisional hernia represents a rare complication after ventriculoperitoneal shunt positioning due to failure of the fascial suture in the site of abdominal entrance of ventriculoperitoneal catheter. Clinical presentation can be extremely variable, according to patient’s performance status, herniated material constitution (i.e. mesenteric fat, bowel loops or both) and complication occurrence (e.g. strangulation or intestinal obstruction). Early diagnosis is fundamental in order to surgically repair the defect and prevent further complications. We present the case of a paucisymptomatic incisional hernia following ventriculoperitoneal shunt positioning. Diagnosis was made by means of ultrasound and confirmed by means of computed tomography. The patient was successfully managed by means of surgical repositioning of herniated loop and re-suture. PMID:27761180

  9. Quantitative evaluation fo cerebrospinal fluid shunt flow

    SciTech Connect

    Chervu, S.; Chervu, L.R.; Vallabhajosyula, B.; Milstein, D.M.; Shapiro, K.M.; Shulman, K.; Blaufox, M.D.

    1984-01-01

    The authors describe a rigorous method for measuring the flow of cerebrospinal fluid (CSF) in shunt circuits implanted for the relief of obstructive hydrocephalus. Clearance of radioactivity for several calibrated flow rates was determined with a Harvard infusion pump by injecting the Rickham reservoir of a Rickham-Holter valve system with 100 ..mu..Ci of Tc-99m as pertechnetate. The elliptical and the cylindrical Holter valves used as adjunct valves with the Rickham reservoir yielded two different regression lines when the clearances were plotted against flow rats. The experimental regression lines were used to determine the in vivo flow rates from clearances calculated after injecting the Rickham reservoirs of the patients. The unique clearance characteristics of the individual shunt systems available requires that calibration curves be derived for an entire system identical to one implanted in the patient being evaluated, rather than just the injected chamber. Excellent correlation between flow rates and the clinical findings supports the reliability of this method of quantification of CSF shunt flow, and the results are fully accepted by neurosurgeons.

  10. Active shunt capacitance cancelling oscillator circuit

    DOEpatents

    Wessendorf, Kurt O.

    2003-09-23

    An oscillator circuit is disclosed which can be used to produce oscillation using a piezoelectric crystal, with a frequency of oscillation being largely independent of any shunt capacitance associated with the crystal (i.e. due to electrodes on the surfaces of the crystal and due to packaging and wiring for the crystal). The oscillator circuit is based on a tuned gain stage which operates the crystal at a frequency, f, near a series resonance frequency, f.sub.S. The oscillator circuit further includes a compensation circuit that supplies all the ac current flow through the shunt resistance associated with the crystal so that this ac current need not be supplied by the tuned gain stage. The compensation circuit uses a current mirror to provide the ac current flow based on the current flow through a reference capacitor that is equivalent to the shunt capacitance associated with the crystal. The oscillator circuit has applications for driving piezoelectric crystals for sensing of viscous, fluid or solid media by detecting a change in the frequency of oscillation of the crystal and a resonator loss which occur from contact of an exposed surface of the crystal by the viscous, fluid or solid media.

  11. Ventriculoperitoneal shunt dysfunction and constipation: a chart review.

    PubMed

    Bragg, C L; Edwards-Beckett, J; Eckle, N; Principe, K; Terry, D

    1994-10-01

    Children treated for hydrocephalus frequently experience chronic constipation. A retrospective chart review was conducted to determine if there is a population of children with ventriculoperitoneal (VP) shunt dysfunction in whom constipation might be a factor in the shunt dysfunction. Of 51 cases reviewed, 19 had documented constipation, such as no bowel movement for 2 or more days, small hard ball-like stools or fullness of the colon noted on physical examination or abdominal radiographs. In 6 cases, a bowel cleansing was performed and signs and symptoms of shunt dysfunction resolved without shunt revision. This review suggests that constipation may affect the fluid or pressure dynamics of the VP shunt and contribute to shunt dysfunction.

  12. CSF shunt complications: what the abdominal imager needs to know.

    PubMed

    Rinker, Eric K; Williams, Todd R; Myers, Daniel T

    2015-08-01

    Cerebrospinal fluid (CSF) shunting has been a mainstay in the treatment of hydrocephalus for many decades. With a reported 33,000 shunt placement procedures performed in the US annually, and a lifetime revision rate approaching 50%, abdominal radiologists must be familiar with the typical imaging appearance of an array of shunt complications. Complications related to the peritoneal portion of the shunt have been reported in up to 25% of patients. We present a comprehensive pictorial essay including computed tomography, conventional radiography, ultrasound, and nuclear medicine examples illustrating abdominal complications related to CSF shunting and a review of the current literature. The purpose of this pictorial essay is to provide multimodality imaging examples of CSF shunt complications and familiarize the abdominal imager with the spectrum of findings.

  13. Shunt current loss of the vanadium redox flow battery

    NASA Astrophysics Data System (ADS)

    Xing, Feng; Zhang, Huamin; Ma, Xiangkun

    The shunt current loss is one of main factors to affect the performance of the vanadium redox flow battery, which will shorten the cycle life and decrease the energy transfer efficiency. In this paper, a stack-level model based on the circuit analog method is proposed to research the shunt current loss of the vanadium redox flow battery, in which the SOC (state of charge) of electrolyte is introduced. The distribution of shunt current is described in detail. The sensitive analysis of shunt current is reported. The shunt current loss in charge/discharge cycle is predicted with the given experimental data. The effect of charge/discharge pattern on the shunt current loss is studied. The result shows that the reduction of the number of single cells in series, the decrease of the resistances of manifold and channel and the increase of the power of single cell will be the further development for the VRFB stack.

  14. Factors affecting ventriculoperitoneal shunt survival in adult patients

    PubMed Central

    Khan, Farid; Rehman, Abdul; Shamim, Muhammad S.; Bari, Muhammad E.

    2015-01-01

    Background: Ventriculoperitoneal (VP) shunt insertion remains the mainstay of treatment for hydrocephalus despite a high rate of complications. The predictors of shunt malfunction have been studied mostly in pediatric patients. In this study, we report our 11-year experience with VP shunts in adult patients with hydrocephalus. We also assess the various factors affecting shunt survival in a developing country setting. Methods: A retrospective chart analysis was conducted for all adult patients who had undergone shunt placement between the years 2001 and 2011. Kaplan–Meier curves were used to determine the duration from shunt placement to first malfunction and log-rank (Cox–Mantel) tests were used to determine the factors affecting shunt survival. Results: A total of 227 patients aged 18–85 years (mean: 45.8 years) were included in the study. The top four etiologies of hydrocephalus included post-cranial surgery (23.3%), brain tumor or cyst (22.9%), normal pressure hydrocephalus (15%), and intracranial hemorrhage (13.7%). The overall incidence of shunt malfunction was 15.4% with the median time to first shunt failure being 120 days. Etiology of hydrocephalus (P = 0.030) had a significant association with the development of shunt malfunction. Early shunt failure was associated with age (P < 0.001), duration of hospital stay (P < 0.001), Glasgow Coma Scale (GCS) score less than 13 (P = 0.010), excision of brain tumors (P = 0.008), and placement of extra-ventricular drains (P = 0.033). Conclusions: Patients with increased age, prolonged hospital stay, GCS score of less than 13, extra-ventricular drains in situ, or excision of brain tumors were more likely to experience early shunt malfunction. PMID:25722930

  15. Diagnostic imaging of ventriculoperitoneal shunt malfunctions and complications.

    PubMed

    Goeser, C D; McLeary, M S; Young, L W

    1998-01-01

    Most pediatric patients with hydrocephalus are treated with ventriculoperitoneal (VP) shunt placement. However, shunt malfunction is common and is usually caused by mechanical failure. Shunt obstructions may be confirmed with radioisotope examination or with fluoroscopically guided injection of iodinated contrast material into the shunt reservoir. Disconnections or breaks are more readily detected at radiography in cases in which barium-impregnated shunt tubing was used. Migration and leakage may also occur. Cerebrospinal pseudocysts may be demonstrated with plain radiography and further evaluated with computed tomography (CT) and sonography. In increasing hydrocephalus, plain radiography may reveal sutural diastasis and increased cranial cavity size, and CT can be used to evaluate ventricle size. In cases of enlarging intracranial cysts, injection of iodinated contrast material followed by CT can help document a connection between the cyst and the ventricles. Ventriculitis and meningitis can be visualized at CT and magnetic resonance imaging as enhancement of the ventricular ependymal lining or cerebral cortical sulci. Other complications associated with VP shunts include surgery-related complications, shunt overdrainage and slit-ventricle syndrome, neoplastic metastasis, pleural effusion, and complications related to shunt variants. Imaging analysis is an essential adjunct to the clinical evaluation of patients with suspected VP shunt malfunctions or complications. Radiologists should be familiar with these potential problems and the diagnostic utility of various imaging modalities.

  16. Referred shoulder pain from ventriculoperitoneal shunts. Report of three cases.

    PubMed

    Tubbs, R Shane; Wellons, John C; Blount, Jeffrey P; Grabb, Paul A; Oakes, W Jerry

    2005-03-01

    The authors report on three pediatric patients with ventriculoperitoneal (VP) shunts who presented with chronic right shoulder pain. Imaging revealed that the distal peritoneal catheter was positioned between the right hemidiaphragm and liver. Following surgical repositioning of the distal tubing, all patients experienced resolution of their shoulder pain, which has not recurred. Although seemingly rare, referred shoulder pain from a VP shunt should be added to the list of complications seen with this method of cerebrospinal fluid diversion. The clinician who cares for patients with VP shunts may wish to evaluate cases of shoulder pain without obvious neural or musculoskeletal cause by performing imaging of the distal shunt tubing.

  17. Ventriculoperitoneal shunt malfunction caused by proximal catheter fat obstruction.

    PubMed

    Mizrahi, Cezar José; Spektor, Sergey; Margolin, Emil; Shoshan, Yigal; Ben-David, Eliel; Cohen, José E; Moscovici, Samuel

    2016-08-01

    Ventriculoperitoneal (VP) shunt placement is the mainstay of treatment for hydrocephalus, yet shunts remain vulnerable to a variety of complications. Although fat droplet migration into the subarachnoid space and cerebrospinal fluid pathways following craniotomy has been observed, a VP shunt obstruction with fat droplets has never been reported to our knowledge. We present the first reported case of VP shunt catheter obstruction by migratory fat droplets in a 55-year-old woman who underwent suboccipital craniotomy for removal of a metastatic tumor of the left medullocerebellar region, without fat harvesting. A VP shunt was inserted 1month later due to communicating hydrocephalus. The patient presented with gait disturbance, intermittent confusion, and pseudomeningocele 21days after shunt insertion. MRI revealed retrograde fat deposition in the ventricular system and VP shunt catheter, apparently following migration of fat droplets from the fatty soft tissue of the craniotomy site. Spinal tap revealed signs of aseptic meningitis. Steroid treatment for aseptic "lipoid" meningitis provided symptom relief. MRI 2months later revealed partial fat resorption and resolution of the pseudomeningocele. VP shunt malfunction caused by fat obstruction of the ventricular catheter should be acknowledged as a possible complication in VP shunts after craniotomy, even in the absence of fat harvesting.

  18. Superconducting fault current-limiter with variable shunt impedance

    SciTech Connect

    Llambes, Juan Carlos H; Xiong, Xuming

    2013-11-19

    A superconducting fault current-limiter is provided, including a superconducting element configured to resistively or inductively limit a fault current, and one or more variable-impedance shunts electrically coupled in parallel with the superconducting element. The variable-impedance shunt(s) is configured to present a first impedance during a superconducting state of the superconducting element and a second impedance during a normal resistive state of the superconducting element. The superconducting element transitions from the superconducting state to the normal resistive state responsive to the fault current, and responsive thereto, the variable-impedance shunt(s) transitions from the first to the second impedance. The second impedance of the variable-impedance shunt(s) is a lower impedance than the first impedance, which facilitates current flow through the variable-impedance shunt(s) during a recovery transition of the superconducting element from the normal resistive state to the superconducting state, and thus, facilitates recovery of the superconducting element under load.

  19. Semi-shunt field emission in electronic devices

    SciTech Connect

    Karpov, V. G.; Shvydka, Diana

    2014-08-04

    We introduce a concept of semi-shunts representing needle shaped metallic protrusions shorter than the distance between a device electrodes. Due to the lightening rod type of field enhancement, they induce strong electron emission. We consider the corresponding signature effects in photovoltaic applications; they are: low open circuit voltages and exponentially strong random device leakiness. Comparing the proposed theory with our data for CdTe based solar cells, we conclude that stress can stimulate semi-shunts' growth making them shunting failure precursors. In the meantime, controllable semi-shunts can play a positive role mitigating the back field effects in photovoltaics.

  20. A laparoscopic technique for retrieval and prevention of migration of ventriculoperitoneal shunt tubing.

    PubMed

    Klee, Vanessa M; Craft, Randall O; Zimmerman, Richard S; Harold, Kristi L

    2009-01-01

    A 31-year-old female with a history of pseudotumor cerebri presented with headache and abdominal discomfort after placement of a ventriculoperitoneal (VP) shunt. The VP shunt was placed after prior failure and revision of a lumbar peritoneal shunt. Computed tomography demonstrated shunt migration into the subcutaneous tissue. Laparoscopy was used to reposition the VP shunt, directing the shunt toward the pelvis. The patient presented for further evaluation one month later, at which point the shunt was shown to have migrated into the subcutaneous tissue once again. Laparoscopy was again used to reposition the shunt and affix it to the abdominal wall by using polytetrafluoroethylene (PTFE) mesh.

  1. Paediatric ventriculoperitoneal shunt infection caused by Actinomyces neuii.

    PubMed

    Anderson, Ian A; Jarral, Fazain; Sethi, Kavita; Chumas, Paul D

    2014-05-23

    We present the first reported case of ventriculoperitoneal shunt infection secondary to Actinomyces neuii in a paediatric patient. Our patient was managed with temporary shunt removal, intrathecal antibiotics and a prolonged course of intravenous and then oral antibiotics. She went on to make a complete recovery. Subsequent cerebrospinal fluid analysis at 5 months post-treatment demonstrated no evidence of residual infection.

  2. Spontaneous knot; a rare cause of ventriculoperitoneal shunt blockage.

    PubMed

    Mohammed, Wail; Wiig, Ulrikke; Caird, John

    2011-02-01

    A 14-year old X linked congenital hydrocephalus presented with unexplained headaches and vomiting. He had external ventricular drain and intracranial pressure monitoring (ICP). Subsequently, he underwent exploration and removal of previously inserted ventriculoperitoneal (VP) shunts. On retrieval of peritoneal catheters a double knot was noted between his two distal catheters. This case illustrates a rare cause of ventriculoperitoneal shunt malfunction.

  3. [Temporary vascular shunt technique for resource scarce environments].

    PubMed

    Ouattara, N; Mlynski, A; Pierret, C

    2011-10-01

    The purpose of this report is to describe a simple and reproducible technique for temporary vascular shunting. This technique is appropriate only for exceptional situations involving scant resource availability. It is not intended to replace conventional vascular shunting techniques. PMID:22235609

  4. Internal carotid artery rupture caused by carotid shunt insertion

    PubMed Central

    Illuminati, Giulio; Caliò, Francesco G.; Pizzardi, Giulia; Vietri, Francesco

    2015-01-01

    Introduction Shunting is a well-accepted method of maintaining cerebral perfusion during carotid endarterectomy (CEA). Nonetheless, shunt insertion may lead to complications including arterial dissection, embolization, and thrombosis. We present a complication of shunt insertion consisting of arterial wall rupture, not reported previously. Presentation of case A 78-year-old woman underwent CEA combined with coronary artery bypass grafting (CABG). At the time of shunt insertion an arterial rupture at the distal tip of the shunt was detected and was repaired via a small saphenous vein patch. Eversion CEA and subsequent CABG completed the procedure whose postoperative course was uneventful. Discussion Shunting during combined CEA-CABG may be advisable to assure cerebral protection from possible hypoperfusion due to potential hemodynamic instability of patients with severe coronary artery disease. Awareness and prompt management of possible shunt-related complications, including the newly reported one, may contribute to limiting their harmful effect. Conclusion Arterial wall rupture is a possible, previously not reported, shunt-related complication to be aware of when performing CEA. PMID:26255001

  5. 21 CFR 882.4545 - Shunt system implantation instrument.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Shunt system implantation instrument. 882.4545 Section 882.4545 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4545 Shunt system implantation instrument. (a) Identification....

  6. 49 CFR 236.724 - Circuit, shunt fouling.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Circuit, shunt fouling. 236.724 Section 236.724... Circuit, shunt fouling. The track circuit in the fouling section of a turnout, connected in multiple with the track circuit in the main track....

  7. 49 CFR 236.724 - Circuit, shunt fouling.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Circuit, shunt fouling. 236.724 Section 236.724... Circuit, shunt fouling. The track circuit in the fouling section of a turnout, connected in multiple with the track circuit in the main track....

  8. 49 CFR 236.724 - Circuit, shunt fouling.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Circuit, shunt fouling. 236.724 Section 236.724... Circuit, shunt fouling. The track circuit in the fouling section of a turnout, connected in multiple with the track circuit in the main track....

  9. 21 CFR 874.3850 - Endolymphatic shunt tube with valve.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3850 Endolymphatic shunt tube with valve. (a) Identification. An endolymphatic shunt tube with valve is a device that consists... device is the FDA guidance document “Class II Special Controls Guidance Document: Endolymphatic...

  10. 21 CFR 874.3850 - Endolymphatic shunt tube with valve.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3850 Endolymphatic shunt tube with valve. (a) Identification. An endolymphatic shunt tube with valve is a device that consists... device is the FDA guidance document “Class II Special Controls Guidance Document: Endolymphatic...

  11. 21 CFR 876.5955 - Peritoneo-venous shunt.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Peritoneo-venous shunt. 876.5955 Section 876.5955 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5955 Peritoneo-venous shunt....

  12. 21 CFR 876.5955 - Peritoneo-venous shunt.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Peritoneo-venous shunt. 876.5955 Section 876.5955 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5955 Peritoneo-venous shunt....

  13. 21 CFR 876.5955 - Peritoneo-venous shunt.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Peritoneo-venous shunt. 876.5955 Section 876.5955 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5955 Peritoneo-venous shunt....

  14. 21 CFR 876.5955 - Peritoneo-venous shunt.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Peritoneo-venous shunt. 876.5955 Section 876.5955 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5955 Peritoneo-venous shunt....

  15. 49 CFR 236.724 - Circuit, shunt fouling.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Circuit, shunt fouling. 236.724 Section 236.724... Circuit, shunt fouling. The track circuit in the fouling section of a turnout, connected in multiple with the track circuit in the main track....

  16. 21 CFR 874.3850 - Endolymphatic shunt tube with valve.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Endolymphatic shunt tube with valve. 874.3850... tube with valve. (a) Identification. An endolymphatic shunt tube with valve is a device that consists of a pressure-limiting valve associated with a tube intended to be implanted in the inner ear...

  17. 21 CFR 874.3850 - Endolymphatic shunt tube with valve.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Endolymphatic shunt tube with valve. 874.3850... tube with valve. (a) Identification. An endolymphatic shunt tube with valve is a device that consists of a pressure-limiting valve associated with a tube intended to be implanted in the inner ear...

  18. 21 CFR 874.3850 - Endolymphatic shunt tube with valve.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Endolymphatic shunt tube with valve. 874.3850... tube with valve. (a) Identification. An endolymphatic shunt tube with valve is a device that consists of a pressure-limiting valve associated with a tube intended to be implanted in the inner ear...

  19. Shunt attachment and method for interfacing current collection systems

    DOEpatents

    Denney, Paul E.; Iyer, Natraj C.; Hannan, III, William F.

    1992-01-01

    A composite brush to shunt attachment wherein a volatile component of a composite but mostly metallic brush, used for current collection purposes, does not upon welding or brazing, adversely affect the formation of the interfacial bond with a conductive shunt which carries the current from the zone of the brush. The brush to shunt attachment for a brush material of copper-graphite composite and a shunt of copper, or substituting silver for copper as an alternative, is made through a hot isostatic pressing (HIP). The HIP process includes applying high pressure and temperature simultaneously at the brush to shunt interface, after it has been isolated or canned in a metal casing in which the air adjacent to the interface has been evacuated and the interfacial area has been sealed before the application of pressure and temperature.

  20. Shunt attachment and method for interfacing current collection systems

    DOEpatents

    Denney, P.E.; Iyer, N.C.; Hannan, W.F. III.

    1992-12-08

    A composite brush to shunt attachment wherein a volatile component of a composite but mostly metallic brush, used for current collection purposes, does not upon welding or brazing, adversely affect the formation of the interfacial bond with a conductive shunt which carries the current from the zone of the brush. The brush to shunt attachment for a brush material of copper-graphite composite and a shunt of copper, or substituting silver for copper as an alternative, is made through a hot isostatic pressing (HIP). The HIP process includes applying high pressure and temperature simultaneously at the brush to shunt interface, after it has been isolated or canned in a metal casing in which the air adjacent to the interface has been evacuated and the interfacial area has been sealed before the application of pressure and temperature. 6 figs.

  1. The role of lumboperitoneal shunts in the treatment of syringomyelia.

    PubMed

    Oluigbo, Chima O; Thacker, Karen; Flint, Graham

    2010-07-01

    OBJECT The role of thecoperitoneal shunts in the management of syringomyelia is not well defined. In this study, the authors analyze the outcome of lumboperitoneal shunt procedures carried out to treat syringomyelia in their institution. METHODS The authors retrospectively reviewed the medical records of 19 patients who underwent lumboperitoneal shunt procedures for syringomyelia. RESULTS The mean follow-up duration was 25 months (range 3-51 months). Of 16 cases followed up, only 5 patients reported clinical improvement in their preoperative symptoms, but of these, 2 had clear radiological evidence of improvement. Three of 6 patients with syringomyelia due to spinal arachnoiditis improved. CONCLUSIONS Lumboperitoneal shunts may lead to useful improvement in the symptoms of a patient with syringomyelia while avoiding the risk of neurological deterioration inherent in myelotomies required for syrinx shunting procedures.

  2. Biosynthetic route towards saxitoxin and shunt pathway.

    PubMed

    Tsuchiya, Shigeki; Cho, Yuko; Konoki, Keiichi; Nagasawa, Kazuo; Oshima, Yasukatsu; Yotsu-Yamashita, Mari

    2016-02-04

    Saxitoxin, the most potent voltage-gated sodium channel blocker, is one of the paralytic shellfish toxins (PSTs) produced by cyanobacteria and dinoflagellates. Recently, putative biosynthetic genes of PSTs were reported in these microorganisms. We previously synthesized genetically predicted biosynthetic intermediates, Int-A' and Int-C'2, and also Cyclic-C' which was not predicted based on gene, and identified them all in the toxin-producing cyanobacterium Anabaena circinalis (TA04) and the dinoflagellate Alexandrium tamarense (Axat-2). This study examined the incorporation of (15)N-labeled intermediates into PSTs (C1 and C2) in A. circinalis (TA04). Conversions from Int-A' to Int-C'2, from Int-C'2 to Cyclic-C', and from Int-A' and Int-C'2 to C1 and C2 were indicated using high resolution-LC/MS. However, Cyclic-C' was not converted to C1 and C2 and was detected primarily in the extracellular medium. These results suggest that Int-A' and Int-C'2 are genuine precursors of PSTs, but Int-C'2 converts partially to Cyclic-C' which is a shunt product excreted to outside the cells. This paper provides the first direct demonstration of the biosynthetic route towards saxitoxin and a shunt pathway.

  3. Ventriculoperitoneal shunt infection with Listeria innocua.

    PubMed

    Karli, Arzu; Sensoy, Gulnar; Unal, Nevzat; Yanik, Keramettin; Cigdem, Halit; Belet, Nursen; Sofuoglu, Ayse

    2014-08-01

    Listeria species may cause life-threatening events including meningitis and invasive infection in newborns, pregnant women, older and immunodeficient people. The most common Listeria species that causes infection is L. monocytogenes. It is known that Listeria innocua has no pathogenicity. A 9-month-old baby had ventriculoperitoneal shunt and was treated with adrenocorticotropic hormone because of infantile spasms. He was brought to hospital with fever and vomiting. Upon physical examination, the patient seemed uncomfortable and had a temperature of 38.6°C. Laboratory results were as follows: hemoglobin, 6.7 g/dL; leukocyte count, 5420/mm(3) ; platelet count, 169,000/mm(3) ; and C-reactive protein, 100 mg/L (normal <5 mg/L). On analysis of cerebrospinal fluid (CSF), leukocyte count was 480/mm(3) , protein was 46 mg/dL and CSF glucose was 35 mg/dL. L. innocua was isolated in CSF culture. We describe this unusual case of ventriculoperitoneal shunt infection with L. innocua.

  4. Flexural waves focusing through shunted piezoelectric patches

    NASA Astrophysics Data System (ADS)

    Yi, K.; Collet, M.; Ichchou, M.; Li, L.

    2016-07-01

    In this paper, we designed and analyzed a piezo-lens to focus flexural waves in thin plates. The piezo-lens is comprised of a host plate and piezoelectric arrays bonded on the surfaces of the plate. The piezoelectric patches are shunted with negative capacitance circuits. The effective refractive indexes inside the piezo-lens are designed to fit a hyperbolic secant distribution by tuning the negative capacitance values. A homogenized model of a piezo-mechanical system is adopted in the designing process of the piezo-lens. The wave focusing effect is studied by the finite element method. Numerical results show that the piezo-lens can focus flexural waves by bending their trajectories, and is effective in a large frequency band. The piezo-lens has the ability to focus flexural waves at different locations by tuning the shunting negative capacitance values. The piezo-lens is shown to be effective for flexural waves generated by different types of sources.

  5. Parylene MEMS patency sensor for assessment of hydrocephalus shunt obstruction.

    PubMed

    Kim, Brian J; Jin, Willa; Baldwin, Alexander; Yu, Lawrence; Christian, Eisha; Krieger, Mark D; McComb, J Gordon; Meng, Ellis

    2016-10-01

    Neurosurgical ventricular shunts inserted to treat hydrocephalus experience a cumulative failure rate of 80 % over 12 years; obstruction is responsible for most failures with a majority occurring at the proximal catheter. Current diagnosis of shunt malfunction is imprecise and involves neuroimaging studies and shunt tapping, an invasive measurement of intracranial pressure and shunt patency. These patients often present emergently and a delay in care has dire consequences. A microelectromechanical systems (MEMS) patency sensor was developed to enable direct and quantitative tracking of shunt patency in order to detect proximal shunt occlusion prior to the development of clinical symptoms thereby avoiding delays in treatment. The sensor was fabricated on a flexible polymer substrate to eventually allow integration into a shunt. In this study, the sensor was packaged for use with external ventricular drainage systems for clinical validation. Insights into the transduction mechanism of the sensor were obtained. The impact of electrode size, clinically relevant temperatures and flows, and hydrogen peroxide (H2O2) plasma sterilization on sensor function were evaluated. Sensor performance in the presence of static and dynamic obstruction was demonstrated using 3 different models of obstruction. Electrode size was found to have a minimal effect on sensor performance and increased temperature and flow resulted in a slight decrease in the baseline impedance due to an increase in ionic mobility. However, sensor response did not vary within clinically relevant temperature and flow ranges. H2O2 plasma sterilization also had no effect on sensor performance. This low power and simple format sensor was developed with the intention of future integration into shunts for wireless monitoring of shunt state and more importantly, a more accurate and timely diagnosis of shunt failure.

  6. Parylene MEMS patency sensor for assessment of hydrocephalus shunt obstruction.

    PubMed

    Kim, Brian J; Jin, Willa; Baldwin, Alexander; Yu, Lawrence; Christian, Eisha; Krieger, Mark D; McComb, J Gordon; Meng, Ellis

    2016-10-01

    Neurosurgical ventricular shunts inserted to treat hydrocephalus experience a cumulative failure rate of 80 % over 12 years; obstruction is responsible for most failures with a majority occurring at the proximal catheter. Current diagnosis of shunt malfunction is imprecise and involves neuroimaging studies and shunt tapping, an invasive measurement of intracranial pressure and shunt patency. These patients often present emergently and a delay in care has dire consequences. A microelectromechanical systems (MEMS) patency sensor was developed to enable direct and quantitative tracking of shunt patency in order to detect proximal shunt occlusion prior to the development of clinical symptoms thereby avoiding delays in treatment. The sensor was fabricated on a flexible polymer substrate to eventually allow integration into a shunt. In this study, the sensor was packaged for use with external ventricular drainage systems for clinical validation. Insights into the transduction mechanism of the sensor were obtained. The impact of electrode size, clinically relevant temperatures and flows, and hydrogen peroxide (H2O2) plasma sterilization on sensor function were evaluated. Sensor performance in the presence of static and dynamic obstruction was demonstrated using 3 different models of obstruction. Electrode size was found to have a minimal effect on sensor performance and increased temperature and flow resulted in a slight decrease in the baseline impedance due to an increase in ionic mobility. However, sensor response did not vary within clinically relevant temperature and flow ranges. H2O2 plasma sterilization also had no effect on sensor performance. This low power and simple format sensor was developed with the intention of future integration into shunts for wireless monitoring of shunt state and more importantly, a more accurate and timely diagnosis of shunt failure. PMID:27589973

  7. Vascular collateralization along ventriculoperitoneal shunt catheters in moyamoya disease.

    PubMed

    Singla, Amit; Lin, Ning; Ho, Allen L; Scott, R Michael; Smith, Edward R

    2013-06-01

    Surgically created openings such as bur holes can serve as avenues for the development of collateral blood supply to the brain in patients with moyamoya disease. When such collateralization occurs through preexisting shunt catheter sites, the potential exists for perioperative stroke if these vessels are damaged during revision of a ventricular catheter for shunt malfunction. In this paper the authors report on a series of patients with a history of ventriculoperitoneal (VP) shunts who later developed moyamoya disease and were found to have spontaneous transdural collateral vessels at ventricular catheter sites readily visualized on diagnostic angiography. A consecutive surgical series of 412 patients with moyamoya disease treated at Boston Children's Hospital from 1990 to 2010 were reviewed to identify patients with concomitant moyamoya and a VP shunt. The clinical records and angiograms of these patients were reviewed to determine the extent of bur hole collaterals through the shunt site. Three patients were identified who had VP shunts placed for hydrocephalus and subsequently developed moyamoya disease. All 3 patients demonstrated spontaneous transdural collaterals at the ventricular catheter bur hole, as confirmed by angiography during the workup for moyamoya disease. No patients required subsequent revision of their ventricular catheters following the diagnosis of moyamoya. All patients have remained stroke free and clinically stable following pial synangiosis. Although the association of moyamoya and shunted hydrocephalus is rare, it may present a significant potential problem for the neurosurgeon treating a shunt malfunction in this patient population, because shunt bur holes may become entry sites for the ingrowth of significant cortical transdural collateral blood supply to the underlying brain. Shunt revision might therefore be associated with an increased risk of postoperative stroke or operative-site hemorrhage in this population if this

  8. Portosystemic Shunt Surgery in Patients with Idiopathic Noncirrhotic Portal Hypertension.

    PubMed

    Karagul, Servet; Yagci, Mehmet Ali; Tardu, Ali; Ertugrul, Ismail; Kirmizi, Serdar; Sumer, Fatih; Isik, Burak; Kayaalp, Cuneyt; Yilmaz, Sezai

    2016-01-01

    BACKGROUND Idiopathic noncirrhotic portal hypertension (INCPH) is a rare disease characterized by increased portal venous pressure in the absence of cirrhosis and other causes of liver diseases. The aim of the present study was to present our results in using portosystemic shunt surgery in patients with INCPH. MATERIAL AND METHODS Patients who had been referred to our Liver Transplantation Institute for liver transplantation and who had undergone surgery from January 2010 to December 2015 were retrospectively analyzed. Patients with INCPH who had undergone portosystemic shunt procedure were included in the study. Age, sex, symptoms and findings, type of portosystemic shunt, and postoperative complications were assessed. RESULTS A total of 1307 patients underwent liver transplantation from January 2010 to December 2015. Eleven patients with INCPH who did not require liver transplantation were successfully operated on with a portosystemic shunt procedure. The mean follow-up was 30.1±19 months (range 7-69 months). There was no mortality in the perioperative period or during the follow-up. Two patients underwent surgery again due to intra-abdominal hemorrhage; one had bleeding from the surgical site except the portacaval anastomosis and the other had bleeding from the h-graft anastomosis. No patient developed encephalopathy and no patient presented with esophageal variceal bleeding after portosystemic shunt surgery. Shunt thrombosis occurred in 1 patient (9.9%). Only 1 patient developed ascites, which was controlled medically. CONCLUSIONS Portosystemic shunt surgery is a safe and effective procedure for the treatment of patients with INCPH. PMID:27194018

  9. The hydrokinetic parameters of shunts for hydrocephalus might be inadequate.

    PubMed

    Sotelo, Julio

    2012-01-01

    Long-term treatment of hydrocephalus continues to be dismal. Shunting is the neurosurgical procedure more frequently associated with complications, which are mostly related with dysfunctions of the shunting device, rather than to mishaps of the rather simple surgical procedure. Overdrainage and underdrainage are the most common dysfunctions; of them, overdrainage is a conspicuous companion of most devices. Even when literally hundreds of different models have been proposed, developed, and tested, overdrainage has plagued all shunts for the last 60 years. Several investigations have demonstrated that changes in the posture of the subject induce unavoidable and drastic differences of intraventricular hydrokinetic pressure and cerebrospinal fluid (CSF) drainage through the shunt. Of all the parameters that participate in the pathophysiology of hydrocephalus, the only invariable one is cerebrospinal fluid production at a constant rate of approximately 0.35 ml/min. However, this feature has not been considered in the design of currently available shunts. Our experimental and clinical studies have shown that a simple shunt, whose drainage capacity complies with this unique parameter, would prevent most complications of shunting for hydrocephalus.

  10. Exploration of nonlinearly shunted piezoelectrics as vibration absorbers

    NASA Astrophysics Data System (ADS)

    Zhou, B.; Zang, C.; Wang, X.

    2016-09-01

    Practical realization of a nonlinearly shunted piezoelectric vibration absorber is numerically explored in this research. It is widely known that the linear resonant piezoelectric shunting strategy, acting as a tuned mass damper, is limited by the massive inductance required in low-frequency cases and sensitivity to drifts in structural frequencies. In order to overcome this limitation, a nonlinear piezoelectric shunting strategy is proposed based on the nonlinear energy sink theory. The essential idea is to passively absorb vibrational energy from the host structure through the intentional use of nonlinearity in piezoelectric shunting. The nonlinearly shunted piezoelectrics are supposed to work over a broad frequency band with a smaller inductance requirement compared with the linear resonant shunting. The nonlinearly shunted piezoelectric vibration absorber is built and applied in a cantilevered beam. Major challenges coming from the nonlinear tuning design for an effective vibration absorber exempted from high isolated response curves will be covered in this research. This numerical study is supposed to pave the way for experimental investigations that are currently in process.

  11. Shunt malfunction presenting with symptomatic syringomyelia: Demonstrated on contrast ventriculogram

    PubMed Central

    Aniruddha, T. J; Pruthi, Nupur

    2014-01-01

    Ventriculoperitoneal (VP) shunt malfunction commonly presents as raised intracranial pressure. Rarely, when the central canal of the spinal cord communicates with the 4th ventricle, shunt malfunction can present as an expanding syrinx. The diagnosis is often delayed, resulting in severe morbidity. Some of these patients undergo repeated syrinx surgeries without much benefits. We report a case of chronic tuberculous meningitis with shunt malfunction presenting as an expanding spinal canal syrinx and quadriparesis. Fourth ventricular communication with syrinx was demonstrated with the help of a contrast ventriculogram. After shunt revision, syrinx resolved completely and the patient made significant improvement in his neurological deficits. The present case illustrates that a historical and rarely used investigation like contrast ventriculogram aids in the diagnosis and management even in the current neurosurgical practice. All patients with late onset syrinx and a previous VP shunt need to be investigated for shunt malfunction before considering syrinx surgery. A simple shunt revision resolves the syrinx in such conditions and avoids more complex procedures like Foramen magnum decompression. Relevant literature has been reviewed; pathophysiology and management options have been discussed. PMID:25250067

  12. The hydrokinetic parameters of shunts for hydrocephalus might be inadequate.

    PubMed

    Sotelo, Julio

    2012-01-01

    Long-term treatment of hydrocephalus continues to be dismal. Shunting is the neurosurgical procedure more frequently associated with complications, which are mostly related with dysfunctions of the shunting device, rather than to mishaps of the rather simple surgical procedure. Overdrainage and underdrainage are the most common dysfunctions; of them, overdrainage is a conspicuous companion of most devices. Even when literally hundreds of different models have been proposed, developed, and tested, overdrainage has plagued all shunts for the last 60 years. Several investigations have demonstrated that changes in the posture of the subject induce unavoidable and drastic differences of intraventricular hydrokinetic pressure and cerebrospinal fluid (CSF) drainage through the shunt. Of all the parameters that participate in the pathophysiology of hydrocephalus, the only invariable one is cerebrospinal fluid production at a constant rate of approximately 0.35 ml/min. However, this feature has not been considered in the design of currently available shunts. Our experimental and clinical studies have shown that a simple shunt, whose drainage capacity complies with this unique parameter, would prevent most complications of shunting for hydrocephalus. PMID:22530174

  13. The hydrokinetic parameters of shunts for hydrocephalus might be inadequate

    PubMed Central

    Sotelo, Julio

    2012-01-01

    Long-term treatment of hydrocephalus continues to be dismal. Shunting is the neurosurgical procedure more frequently associated with complications, which are mostly related with dysfunctions of the shunting device, rather than to mishaps of the rather simple surgical procedure. Overdrainage and underdrainage are the most common dysfunctions; of them, overdrainage is a conspicuous companion of most devices. Even when literally hundreds of different models have been proposed, developed, and tested, overdrainage has plagued all shunts for the last 60 years. Several investigations have demonstrated that changes in the posture of the subject induce unavoidable and drastic differences of intraventricular hydrokinetic pressure and cerebrospinal fluid (CSF) drainage through the shunt. Of all the parameters that participate in the pathophysiology of hydrocephalus, the only invariable one is cerebrospinal fluid production at a constant rate of approximately 0.35 ml/min. However, this feature has not been considered in the design of currently available shunts. Our experimental and clinical studies have shown that a simple shunt, whose drainage capacity complies with this unique parameter, would prevent most complications of shunting for hydrocephalus. PMID:22530174

  14. Atrial-caval shunting (ACS) after trauma.

    PubMed

    Kudsk, K A; Sheldon, G F; Lim, R C

    1982-02-01

    Since 1968 the atrial-caval shunt (ACS), along with inflow occlusion at the porta hepatis, has been used at San Francisco General Hospital in 18 trauma patients to control massive hemorrhage from the inferior vena cava, hepatic veins, or liver. Thirteen patients died from irreversible shock. Five patients survived their initial injuries; one of them died 45 days later from the complications of shock and sepsis. No patients survived who sustained blunt trauma and were admitted in cardiac arrest. Only one of ten patients with BP less than 70 mm Hg after resuscitation survived, whereas four of eight with BP greater than 70 mm Hg survived. ACS was used to control caval injuries in seven patients (one survivor), severe hepatic parenchymal fractures in four patients (two survivors), and combined hepatic and caval injuries in seven patients (two survivors). Survivors had an average of 5.75 associated injuries; nonsurvivors had 3.8. No complications of ACS occurred in the surviving patients.

  15. 49 CFR 236.309 - Loss of shunt protection; where required.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Loss of shunt protection; where required. 236.309... Standards § 236.309 Loss of shunt protection; where required. (a) A loss of shunt of 5 seconds or less shall not permit an established route to be changed at an automatic interlocking. (b) A loss of shunt of...

  16. Return to the emergency department after ventricular shunt evaluation.

    PubMed

    Sarda, Samir; Simon, Harold K; Hirsh, Daniel A; Wang, Andrew; Shane Tubbs, R; Chern, Joshua J

    2016-04-01

    OBJECT Patients with CSF shunts are medically complex and frequently present to the emergency department (ED) with suspected shunt malfunction. After adequate evaluation in the ED and proper disposition, some patients return to the ED within a short period of time. In this study, the authors examined the reasons for ED revisits within 7 days of the index ED visit to discern possible preventable returns. METHODS There were 3080 index ED visits made by patients with shunted hydrocephalus between 2010 and 2013. Index ED visits preceded by another ED visit or neurosurgical procedure within 60 days were excluded. Index ED visits for reasons unrelated to shunt function and those that led directly to admissions and shunt revision surgeries were also excluded. The remaining 1509 ED visits were eligible for analysis in this study. Final dispositions from the index ED visit included home (1176 cases), admission to the neurosurgery service for observation (134 cases), and admission to other services (199 cases). Subsequent events within 7 days, including ED revisits, hospital admissions, and shunt-related surgery were recorded, and reasons for the ED revisits were categorized based on whether the visit was related to shunt function concerns. Clinical and socioeconomic factors were analyzed for their association with ED revisits by using statistical methods. RESULTS Of the 1176 patients discharged home from the ED after shunt function evaluation, 101 (8.6%) returned to the ED within 7 days. Of the 134 patients admitted to the neurosurgery service for observation only, 8 (6.0%) returned to the ED within 7 days of discharge. Of the 199 patients admitted to hospital services other than neurosurgery, 13 (6.5%) returned to the ED within 7 days of discharge. The reasons for ED revisits vary (total of 122 visits combining the 3 groups), but at least 60% of the revisits were clearly unrelated to shunt function. A younger age, daytime arrival to the ED, and living within the

  17. Delayed intracerebellar hemorrhage secondary to lumboperitoneal shunt insertion

    PubMed Central

    Er, Uygur; Akyol, Çetin; Bavbek, Murad

    2016-01-01

    Aim of this paper is to present and discuss a case of a delayed cerebellar parenchymal hemorrhage developing after L/P shunt placement with a NPH patient. A hypertensive patient admitted to our clinic with a diagnosis of NPH. The patient was placed a pressure adjustable L/P shunt without any surgical complication. He was discharged with an uneventful period. The patient was admitted to the emergency clinic of our hospital with a 1.5 × 1.5 cm diameter hematoma at the left cerebellar hemisphere on 2 days after his discharge. CSF drainage by an L/P shunt can generate intracerebellar hemorrhages especially in hypertensive patients.

  18. [Abdominal pseudocyst as a complication of ventriculoperitoneal shunt].

    PubMed

    Shakir, Shawnim; Hegelund, Sture

    2013-09-16

    The abdominal pseudocyst is an unfrequent complication in patients with ventriculoperitoneal shunts. Although many cases have been reported in children, it is rare in adult patients. However, a 47-year-old man with congenital hydrocephalus who had been treated with ventriculoperitoneal shunt since the age of three months, was admitted to hospital due to abdominal pain. He was eventually diagnosed radiologically as having an abdominal pseudocyst. Despite this complication being rare, especially in adults, it should be highly suspected whenever an abdominal cyst co-occurs with a ventriculoperitoneal shunt.

  19. Ion beam sputter-etched ventricular catheter for hydrocephalus shunt

    NASA Technical Reports Server (NTRS)

    Banks, B. A. (Inventor)

    1983-01-01

    A cerebrospinal fluid shunt in the form of a ventricular catheter for controlling the condition of hydrocephalus by relieving the excessive cerebrospinal fluid pressure is described. A method for fabrication of the catheter and shunting the cerebral fluid from the cerebral ventricles to other areas of the body is also considered. Shunt flow failure occurs if the ventricle collapse due to improper valve function causing overdrainage. The ventricular catheter comprises a multiplicity of inlet microtubules. Each microtubule has both a large openings at its inlet end and a multiplicity of microscopic openings along its lateral surfaces.

  20. Pollutants removal in subsurface infiltration systems by shunt distributing wastewater with/without intermittent aeration under different shunt ratios.

    PubMed

    Pan, Jing; Yuan, Fang; Zhang, Yang; Huang, Linli; Yu, Long; Zheng, Fanping; Cheng, Fan; Zhang, Jiadi

    2016-10-01

    Matrix dissolved oxygen (DO), removal of COD, TP and nitrogen in subsurface infiltration systems (SISs), named SIS A (without intermittent aeration and shunt distributing wastewater), SIS B (with shunt distributing wastewater) and SIS C (with intermittent aeration and shunt distributing wastewater) were investigated. Aerobic conditions were developed in 50cm depth and anoxic or anaerobic conditions were not changed in 80 and 110cm depth by intermittent aeration. Under appropriate shunt ratios, shunt distributing wastewater improved denitrification and had little influence on COD, TP and NH3-N removal. Under the optimal shunt ratio of 1:2 for SIS C, high average removal rates of COD (90.06%), TP (93.17%), NH3-N (88.20%) and TN (85.79%) were obtained, which were higher than those in SIS A (COD: 82.56%, TP: 92.76%, NH3-N: 71.08%, TN: 49.24%) and SIS B (COD: 81.12%, TP: 92.58%, NH3-N: 69.14%, TN: 58.73%) under the optimal shunt ratio of 1:3.

  1. A neonate with a meningomyelocele complicated by Aeromonas caviae ventriculoperitoneal shunt infection.

    PubMed

    den Butter, C P; Mahieu, L M

    2013-01-01

    We report on a newborn girl with a Aeromonas caviae shunt infection and meningitis after insertion of a ventriculoperitoneal shunt and surgical repair of a meningomyelocele in one procedure. This pathogen has never been reported, related to ventriculoperitoneal shunt infections. Beside the need for surgical revision of the shunt because of shunt obstruction and septa formation in the ventricles, the clinical outcome was good with intravenous cefotaxime therapy.

  2. Malignant cause of ventriculoperitoneal shunt 'pseudocyst': a case report.

    PubMed

    Awori, Jonathan; Wu, Chris Y; Maher, Cormac O

    2015-01-01

    Abdominal pseudocysts are an uncommon complication of ventriculoperitoneal (VP) shunts. We present the case of a 4-year-old boy with a history of complicated hydrocephalus managed with a VP shunt due to sequelae of prematurity. The patient presented with abdominal distention, and a pseudocyst was diagnosed. Despite shunt externalization and aspiration, the pseudocyst continued to produce up to 1 liter of serosanguineous fluid per day. After MRI revealed malignant features within the pseudocyst, laparotomy was performed and the pseudocyst was partially excised. Pathology reports suggested sarcoma. The cystic mass grew back aggressively, accompanied by distant metastasis. The patient's condition deteriorated and he died from his disease. To our knowledge, this represents the first report of an abdominal malignancy mimicking a pseudocyst and causing VP shunt failure.

  3. Zero tolerance to shunt infections: can it be achieved?

    PubMed Central

    Choksey, M; Malik, I

    2004-01-01

    Objective: To evaluate the rigid application of a technique of shunt placement aimed at the eradication of postoperative shunt infection in neurosurgical practice. Method: All shunt procedures were performed or closely supervised by the senior author (MSC). The essentials were the use of intravenous peri- and postoperative antimicrobials, rigid adherence to classical aseptic technique, liberal use of topical antiseptic (Betadine®), and avoidance of haematomas. Results: Of 176 operations, 93 were primary procedures; 33 patients underwent revisions, some multiple. Only one infection occurred, seven months postoperatively, secondary to appendicitis with peritonitis. The infecting Streptococcus faecalis appeared to ascend from the abdominal cavity. Conclusion: A rigidly applied protocol and strict adherence to sterile technique can reduce shunt infections to a very low level. PMID:14707314

  4. Should transjugular intrahepatic portosystemic shunt stent grafts be underdilated?

    PubMed

    Gaba, Ron C; Parvinian, Ahmad; Minocha, Jeet; Casadaban, Leigh C; Knuttinen, M Grace; Ray, Charles E; Bui, James T

    2015-03-01

    Although underdilation of transjugular intrahepatic portosystemic shunt (TIPS) stent grafts is commonly performed to limit complications arising from excessive portosystemic shunting, it is uncertain whether underdilated stents retain their smaller diameter indefinitely or eventually expand to nominal caliber. In this investigation, postprocedure computed tomography (CT) was used to compare diameters of underdilated TIPSs and TIPSs expanded to a nominal diameter of 10 mm in 61 cases. The groups had comparable shunt diameters on post-TIPS imaging (9.8 mm vs 9.9 mm; P = .079), with similar incidences of hepatic encephalopathy (34% vs 20%; P = .372), indicating stent self-expansion over time, and bringing into question the advantages of underdilation for customization of shunt caliber.

  5. Percutaneous ultrasound-guided insertion of ventriculo-atrial shunts.

    PubMed

    McCracken, James Albert; Bahl, Anuj; McMullan, John

    2016-08-01

    Ventriculo-atrial (VA) shunts have been in use for >60 years but less frequently so of late. This is due to a combination of the risk of cardiac complications, lack of expertise and a lengthy operation. We present our consecutive prospective series of 10 VA shunts inserted using a percutaneous method employing the Sonowand Invite™ neuronavigation system for both the distal and proximal catheters, over a 13-month period. We had two complications of cases needing revision, but our series highlights a safe and reproducible method of inserting a VA shunt. About 30% of the procedures were carried out by a trainee as the primary surgeon. This technique does not necessarily require the expertise of a complex hydrocephalus surgeon and is thus able to be in the armoury of any neurosurgeon needing to do a VA shunt procedure. The indications, operative data and outcomes of our patients are discussed.

  6. Shunting inhibitory cellular neural networks with chaotic external inputs

    NASA Astrophysics Data System (ADS)

    Akhmet, M. U.; Fen, M. O.

    2013-06-01

    Taking advantage of external inputs, it is shown that shunting inhibitory cellular neural networks behave chaotically. The analysis is based on the Li-Yorke definition of chaos. Appropriate illustrations which support the theoretical results are depicted.

  7. Shunting inhibitory cellular neural networks with chaotic external inputs.

    PubMed

    Akhmet, M U; Fen, M O

    2013-06-01

    Taking advantage of external inputs, it is shown that shunting inhibitory cellular neural networks behave chaotically. The analysis is based on the Li-Yorke definition of chaos. Appropriate illustrations which support the theoretical results are depicted.

  8. Routine cerebrospinal fluid analysis during 'de novo' ventriculoperitoneal shunt insertion: Single Institution Experience.

    PubMed

    Khalil, Ayman; Mandiwanza, Tafadzwa; Zakaria, Zaitun; Crimmins, Darach

    2016-08-01

    Background Cerebrospinal fluid (CSF) sampling is performed during ventriculoperitoneal (VP) shunting procedure surgery for early detection of infection. We have performed a retrospective study to determine whether routine intraoperative CSF sampling at new VP shunt insertion has predicted shunt infection or changed subsequent surveillance or management. Method From January 2011 to December 2013, 99 patients underwent first time VP shunt insertion at our hospital. The data collected from Beaumont Hospital Information System and operating theatre logbook. The reviewed data were patient demographics, the clinical condition requiring VP shunt procedure, shunt type, date of VP shunt insertion, date of VP shunt infection or malfunction and laboratory data. Results A first time VP shunt insertion procedure was performed in 99 patients. During the VP shunt insertion procedure, 64 patients had CSF sampling for microbiological analysis. The CSF culture was negative in all samples. All patients were followed up for 12 months. During the follow-up period, a total of 15 patients underwent VP shunt revision. Three of the shunt revisions were secondary to infection. The three infected shunt cases had sterile CSF cultures at the time of insertion. Conclusion There appears to be no correlation between CSF sampling during first time VP shunt insertion and the later development VP shunt infection. This questions the need for routine CSF sampling at the time of insertion. This would be confirmed as a part of future randomised trials.

  9. In vitro flow measurements in ion sputtered hydrocephalus shunts

    NASA Technical Reports Server (NTRS)

    Cho, Y. I.; Back, L. H.

    1989-01-01

    This paper describes an experimental procedure for accurate measurements of the pressure-drop/flow rate relationship in hydrocephalus shunts. Using a fish-hook arrangement, small flow rates in a perforated ion-sputtered Teflon microtubule were measured in vitro in a pressured system and were correlated with pressure in the system. Results indicate that appropriate drainage rates could be obtained in the physiological range for hydrocephalus shunts.

  10. Ventriculo-peritoneal shunt infection in a patient on hemodialysis.

    PubMed

    Thet, Yupar; Myint, Win; Myint, Wynne; Hughes, David; Crowe, Alex V; Banerjee, Anindya

    2008-07-01

    Sepsis is an important and serious complication in hemodialysis (HD) patients. Here we report on a case of spina bifida with ventriculo-peritoneal (VP) shunt infection who was on HD and underwent at least 5 months of investigations before a source of the infection was found and eventually treated successfully. We believe this to be the first reported case of VP shunt-associated sepsis in a patient on HD.

  11. Hearing Loss in Patients with Shunt-Treated Hydrocephalus.

    PubMed

    Panova, Margarita V; Geneva, Ina E; Madjarova, Kalina I; Bosheva, Miroslava N

    2015-01-01

    Hearing loss is a common manifestation of the long-term complications in patients with shunt treated hydrocephalus along with motor development disturbance, cognitive and visual impairment, epilepsy and endocrine disorders. The aim of the present study was to investigate the alterations of hearing in patients with shunt treated hydrocephalus of non-tumor etiology and at least one year after implantation of ventriculo-peritoneal shunt, as well as their impact on the quality of life of patients. The study included 70 patients (age range 1.25 years - 21.25 years) with shunted non-tumor hydrocephalus and at least one year after placement of the shunt system. Hearing alterations were proved by measuring the brainstem auditory evoked potentials (BAEP) for children up to 5 years of age and children with mental retardation; audiograms was used for children older than 5 years with normal neuro-psychological development (NPD). Of the 70 studied patients 17 (24%) had hearing loss (10 bilateral and 7-unilateral) and all of them had sensorineural hearing loss, which is associated with low weight at birth, posthemorrhagic hydrocephalus and brainstem symptoms at the time of diagnosis of hydrocephalus. Hearing pathology was found more often in shunt-treated patients with NPD retardation, poor functional status and low quality of life. Children with shunt-treated hydrocephalus have hearing loss of sensorineural type. Children with brain stem symptomatology at diagnosing hydrocephalus and children with post-hemorrhagic hydrocephalus show higher risk of hearing loss. Children with shunted hydrocephalus and hearing loss show lower NPD, lower quality of life and lower functional status.

  12. Hearing Loss in Patients with Shunt-Treated Hydrocephalus.

    PubMed

    Panova, Margarita V; Geneva, Ina E; Madjarova, Kalina I; Bosheva, Miroslava N

    2015-01-01

    Hearing loss is a common manifestation of the long-term complications in patients with shunt treated hydrocephalus along with motor development disturbance, cognitive and visual impairment, epilepsy and endocrine disorders. The aim of the present study was to investigate the alterations of hearing in patients with shunt treated hydrocephalus of non-tumor etiology and at least one year after implantation of ventriculo-peritoneal shunt, as well as their impact on the quality of life of patients. The study included 70 patients (age range 1.25 years - 21.25 years) with shunted non-tumor hydrocephalus and at least one year after placement of the shunt system. Hearing alterations were proved by measuring the brainstem auditory evoked potentials (BAEP) for children up to 5 years of age and children with mental retardation; audiograms was used for children older than 5 years with normal neuro-psychological development (NPD). Of the 70 studied patients 17 (24%) had hearing loss (10 bilateral and 7-unilateral) and all of them had sensorineural hearing loss, which is associated with low weight at birth, posthemorrhagic hydrocephalus and brainstem symptoms at the time of diagnosis of hydrocephalus. Hearing pathology was found more often in shunt-treated patients with NPD retardation, poor functional status and low quality of life. Children with shunt-treated hydrocephalus have hearing loss of sensorineural type. Children with brain stem symptomatology at diagnosing hydrocephalus and children with post-hemorrhagic hydrocephalus show higher risk of hearing loss. Children with shunted hydrocephalus and hearing loss show lower NPD, lower quality of life and lower functional status. PMID:27180348

  13. Small bowel perforation: a rare complication of ventriculoperitoneal shunt placement

    PubMed Central

    Bourm, Kelsey; Pfeifer, Cory; Zarchan, Adam

    2016-01-01

    Small bowel perforation is a rare complication of ventriculoperitoneal (VP) shunt placement. When seen, it most commonly affects the stomach or colon. We describe a case and image findings of an 8-year-old female who presented with sepsis and erosion of the VP shunt into the small bowel. The imaging findings were confirmed surgically. We also provide an overview of the current literature discussing previously reported cases, clinical features, and treatment.

  14. Design of an intelligent and personalised shunting system for hydrocephalus.

    PubMed

    Momani, Lina; Alkharabsheh, Abdel Rahman; Al-Nuaimy, Waleed

    2008-01-01

    Hydrocephalus is a neurological disease that manifests itself in an elevated fluid pressure within the brain, and if left untreated, may be fatal. It is currently treated using shunt implants, which consist of a mechanical valve and tubes that regulate the pressure of cerebrospinal fluid (CSF) by draining excess fluid into the abdomen. Hydrocephalus shunting systems are no longer expected simply to regulate the intracranial pressure (ICP), but also to offer the option of regaining independence of the shunt. Additionally, they could offer personalised valve management which is one of the main limitations of current shunts. This paper describes the design of a multi-agent system for an intelligent and personalised CSF management system. Patient feedback and intracranial pressure readings will play important roles in the process of CSF regulation and weaning, introduces an element of personalisation to the treatment. The new shunting system would deliver both reactive and goal-driven solutions for the treatment, at the same time the intelligent part of the system will be monitoring how well the shunt is performing. These tasks can be achieved by implementing an agent approach in designing this system. Such system would help us to understand more about the dynamics of hydrocephalus.

  15. First Report of Ventriculoperitoneal Shunt Infection due to Cyberlindnera fabianii

    PubMed Central

    Baghdadi, Jonathan; Hemarajata, Peera; Humphries, Romney; Kelesidis, Theodoros

    2015-01-01

    Fungal infections in the central nervous system (CNS) are associated with significant morbidity and death. Transient fungemia in immunocompetent patients without any other risk factors for fungemia has been suggested as a possible mechanism that may lead to serious fungal ventriculoperitoneal (VP) shunt infections, but evidence is lacking. The clinical spectrum, diagnosis, and optimal therapy of Cyberlindnera fabianii infections remain to be determined. We describe the first case of CNS infection due to C. fabianii that occurred in an immunocompetent adult with a VP shunt. Spontaneous translocation with yeast that is not part of the normal gastrointestinal flora in the setting of ingestion of multiple servings of a fermentation product was the likely source from which Cyberlindnera fabianii gained entrance into the VP shunt system, causing meningitis in this patient. The authors conclude that, in view of the high morbidity associated with yeast infection of the CNS, long-term antifungal therapy should be strongly considered in cases where the VP shunt cannot be completely removed. Transient fungemia may lead to invasive disease in an immunocompetent host with VP shunt, even in the absence of any other risk factors for fungemia and even after remote placement of the VP shunt. PMID:26618013

  16. Shunt switched resistor regulator with diode snubber

    SciTech Connect

    Ekstrand, J.

    1989-03-21

    This patent describes a shunt switched resistor regulator power supply for supplying a variable amount of power to a load comprising: a rectifier means for accepting AC input voltage and converting it to DC output voltage at a positive and a negative terminal; first, second, third, and fourth nodes wherein the first and the fourth nodes are coupled to the positive and negative terminals, respectively; a current limiting resistor coupled between the first and second nodes; a capacitor coupled between the second and fourth nodes; a resistor having parasitic inductance coupled between the second and third nodes; a switch coupled between the third and fourth nodes; and a diode having its anode coupled to the third node and having its cathode coupled to the second node; means coupled to the load terminals for sensing the power being delivered to the load and for controlling the switch to have a duty cycle which results in the desired load current flowing through and a desired voltage appearing across the load in accordance with control input signals received at a control input.

  17. [A case of repeated shunt malfunctions with eosinophilic meningitis caused by silicone allergy].

    PubMed

    Kambara, Mizuki; Miyazaki, Takeshi; Yoshikane, Tsutomu; Sugimoto, Keiji; Akiyama, Yasuhiko

    2014-12-01

    The ventricular-peritoneal shunt for hydrocephalus is a well-known and established method but is sometimes complicated by shunt malfunction due to several causes. Eosinophilic meningitis is a rare disease, but has occasionally been reported as a cause of shunt malfunction. Here, we report the case of a 74-year-old woman with repeated shunt malfunction and eosinophilic meningitis due to a silicone allergy. Originally, the patient received a ventricular-peritoneal shunt for normal pressure hydrocephalus secondary to subarachnoid hemorrhage. However, shunt malfunction was identified 6 weeks later, and the first shunt revision was performed using a new shunt system from a different company. Further evaluation to identify the cause of the shunt malfunction revealed no abnormal findings, except for eosinophilia in the serum and cerebrospinal fluid. A second shunt malfunction was identified 16 weeks after the first shunt revision. We therefore concluded that eosinophilic meningitis caused by a silicone allergy might be the real culprit and a second shunt revision was performed using a silicone "extracted" tube. Since then, the patient's course has been free from shunt malfunction. In this case, the serum and cerebrospinal fluid eosinophilia were useful markers for identifying the cause of repeated shunt malfunctions. The silicone "extracted" tube may be helpful for diagnosis and therapy.

  18. Temporary arterial shunts to maintain limb perfusion after arterial injury: an animal study

    NASA Technical Reports Server (NTRS)

    Dawson, D. L.; Putnam, A. T.; Light, J. T.; Ihnat, D. M.; Kissinger, D. P.; Rasmussen, T. E.; Bradley, D. V. Jr

    1999-01-01

    BACKGROUND: Temporary shunt placement can quickly restore perfusion after extremity arterial injury. This study examined the adequacy of limb blood flow with shunt use, non-heparin-bonded shunt patency over prolonged periods, and the safety of this technique. METHODS: Common iliac arteries were divided and 4.0-mm Silastic Sundt shunts placed in 16 anesthetized pigs. Eight (group I) had shunts placed immediately; eight others (group II) were shunted after an hour of limb ischemia and hemorrhagic shock. Physiologic parameters and femoral artery blood flow in both hindlimbs were continuously monitored. Limb lactic acid generation, oxygen utilization, and hematologic and metabolic effects were serially evaluated for 24 hours. RESULTS: Shunts remained patent in 13 of 16 pigs. Shunts thrombosed in two group I animals because of technical errors, but functioned well after thrombectomy and repositioning. Patency could not be maintained in one animal that died from shock. Flow in group I shunted limbs was 57 (+/-11 SD) % of control. For group II animals in shock, shunted limb flow initially averaged 46 +/- 15% of control, but 4 hours after shunt placement, the mean limb blood flow was the same as in group I. Increased oxygen extraction compensated for the lower flow. Lactic acid production was not increased in comparison to control limbs. CONCLUSION: Shunts provided adequate flow in this model of extremity trauma. Correctly placed shunts stayed patent for 24 hours, without anticoagulation, if shunt placement followed resuscitation.

  19. The right-to-left shunt of crocodilians serves digestion.

    PubMed

    Farmer, C G; Uriona, T J; Olsen, D B; Steenblik, M; Sanders, K

    2008-01-01

    Abstract All amniotes except birds and mammals have the ability to shunt blood past the lungs, but the physiological function of this ability is poorly understood. We studied the role of the shunt in digestion in juvenile American alligators in the following ways. First, we characterized the shunt in fasting and postprandial animals and found that blood was shunted past the lungs during digestion. Second, we disabled the shunt by surgically sealing the left aortic orifice in one group of animals, and we performed a sham surgery in another. We then compared postprandial rates of gastric acid secretion at body temperatures of 19 degrees and 27 degrees C and rates of digestion of bone at 27 degrees C. Twelve hours after eating, maximal rates of gastric acid secretion when measured at 19 degrees and 27 degrees C were significantly less in the disabled group than in sham-operated animals. Twenty-four hours postprandial, a significant decrease was found at 27 degrees C but not at 19 degrees C. For the first half of digestion, dissolution of cortical bone was significantly slower in the disabled animals. These data suggest the right-to-left shunt serves to retain carbon dioxide in the body so that it can be used by the gastrointestinal system. We hypothesize that the foramen of Panizza functions to enrich with oxygen blood that is destined for the gastrointestinal system to power proton pumps and other energy-demanding processes of digestion and that the right-to-left shunt serves to provide carbon dioxide to gastrointestinal organs besides the stomach, such as the pancreas, spleen, upper small intestine, and liver.

  20. Shunt insufficiency due to knot formation in the peritoneal catheter.

    PubMed

    Fekete, Gábor; Nagy, Andrea; Pataki, István; Bognar, László; Novák, László

    2013-07-30

    The authors report a rare case of the peripheral obstruction of a ventriculoperitoneal shunt. Premature baby was operated on hydrocephalus due to germinal matrix bleeding. After two months of implantation of venticuloperitoneal shunt peripheral insufficiency of the system was emerged. During the shunt revision extensive knot formation became visible. We simply cut the catheter above the knot and the working shunt was replaced into the abdominal cavity. The postoperative course was uneventful and the baby was free of complaints for more than one year. The pathomechanism of knot formation is not clear thus the discovery of the problem during the operation is an unexpected event. In our opinion tight knot cannot be spontaneously formed intraabdominally. Loose knots can be developed and can reduce the capacity of liquor flow. We think that the knot tightens during pulling out. Longer peritoneal catheters can precipitate multiple looping and/or axial torquations and increase the peripheral resistance of the shunt. In such cases when the pulling out is challenged conversion to laparotomy is suggested.

  1. Favorable results with syringosubarachnoid shunts for treatment of syringomyelia.

    PubMed

    Tator, C H; Meguro, K; Rowed, D W

    1982-04-01

    From 1969 to 1979, 20 patients with syringomyelia were treated with a syringosubarachnoid shunt. The principal indications for this procedure were: significant progressive neurological deterioration and absent or minimal tonsillar ectopia. There were 15 patients with idiopathic syringomyelia, four with posttraumatic syringomyelia, and one with syringomyelia secondary to spinal arachnoiditis. The operations were performed with an operating microscope, and attention was directed to preserving thearachnoid membrane to ensure proper placement of the distal end of the shunt in an intact subarachnoid space. In all cases, a silicone rubber ventricular catheter was inserted into the syrinx through a posterior midline myelotomy. The average follow-up period was 5 years. A favorable result was obtained in 15 of the 20 patients (75%), including an excellent result with improvement of neurological deficit in 11 patients and a good result with cessation of progression in four patients. In the remaining five patients the result was poor with further progression of neurological deficit. A short duration of preoperative symptoms was usually a favorable prognostic feature. Four patients with a history of less than 6 months all had excellent results. Thirteen patients had a syringosubarachnoid shunt only, and all had good or excellent results. Seven patients had other surgical procedures, before, accompanying, or after shunt placement, and two had favorable results. Thus, the syringosubarachnoid shunt is an effective therapeutic modality for many patients with syringomyelia, particularly if there is little or no tonsillar herniation.

  2. A simplified technique of performing splenorenal shunt (Omar's technique).

    PubMed

    Shah, Omar Javed; Robbani, Irfan

    2005-01-01

    The splenorenal shunt procedure introduced by Robert Linton in 1947 is still used today in those regions of the world where portal hypertension is a common problem. However, because most surgeons find Linton's shunt procedure technically difficult, we felt that a simpler technique was needed. We present the surgical details and results of 20 splenorenal anastomosis procedures performed within a period of 30 months. Half of the patients (Group I) underwent Linton's conventional technique of splenorenal shunt; the other half (Group II) underwent a newly devised, simplified shunt technique. This new technique involves dissection of the fusion fascia of Toldt. The outcome of the 2 techniques was identical with respect to the reduction of preshunt portal pressure. However, our simplified technique was advantageous in that it significantly reduced the duration of surgery (P <0.001) and the amount of intraoperative blood loss (P <0.003). No patient died after either operation. Although Linton's splenorenal shunt is difficult and technically demanding, it is still routinely performed. The new technique described here, in addition to being simpler, helps achieve good vascular control, permits easier dissection of the splenic vein, enables an ideal anastomosis, decreases intraoperative blood loss, and reduces the duration of surgery. Therefore, we recommend the routine use of this simplified technique (Omar's technique) for the surgical treatment of portal hypertension. PMID:16429901

  3. A Subglandular Breast Cerebrospinal Fluid Pseudocyst Following Postsurgical Shunt Migration

    PubMed Central

    Mlynek, Karolina; Frautschi, Russell; Halasa, Brianna; Kwiecien, Grzegorz

    2015-01-01

    Summary: Cerebrospinal fluid (CSF) drainage catheters have been associated with numerous complications in various anatomic locations, because of migration, infection, and obstruction. However, breast-related CSF shunt complications tend to occur infrequently or have seldom been reported in the empirical literature. Therefore, a case is presented detailing a breast pseudocyst caused by migration and subsequent coiling of a ventriculoperitoneal shunt in the right breast pocket. To the best of the authors’ knowledge, this is the first case that has been reported in the peer-reviewed literature of a pseudocyst resulting from a CSF drainage catheter coiling around the breast implant post pancreaticoduodenectomy. Moreover, this case highlights the importance of cross-disciplinary procedural awareness, particularly in regards to breast, ventriculoperitoneal shunt, and pancreatic procedures. PMID:26894004

  4. Temporal and spatial distributions of carbon shunting arc plasma

    NASA Astrophysics Data System (ADS)

    Takaki, Koichi; Konishi, Takumi; Mikawa, Ryota; Takahashi, Kazunori; Yukimura, Ken

    2015-01-01

    The temporal and spatial distributions of a magnetically driven shunting arc plasma were obtained using time-resolved probe measurement. A shunting arc was produced using a carbon rod and accelerated along a pair of rail electrodes by a Lorenz force. The pulse current for driving and maintaining the plasma was supplied from a 20 µF capacitor charged by a dc power supply. Double and single probes were employed to obtain the ion density of the shunting arc plasma. An ion density of 1 × 1019 m-3 was obtained at a distance of 50 mm from the carbon rod 15 µs after applying voltage. The ion density decreased to 2.0 × 1018 m-3 with increasing distance from 50 to 150 mm. The ion density changed with the energy inputted into the plasma.

  5. Executive function improvement in normal pressure hydrocephalus following shunt surgery.

    PubMed

    Gleichgerrcht, Ezequiel; Cervio, Andrés; Salvat, Jorge; Loffredo, Anselmo Rodríguez; Vita, Luciana; Roca, María; Torralva, Teresa; Manes, Facundo

    2009-01-01

    The aim of this investigation was to evaluate improvement of executive functions after shunt surgery in patients with early normal pressure hydrocephalus (NPH). Patients with NPH were assessed before and after shunt surgery with tests shown to be sensitive to damage to the prefrontal cortex (PFC). Significant differences were found between basal and follow-up performances on the Boston Naming Test, the backwards digits span, Part B of the Trail Making Test, and the number of words produced on the phonological fluency task. In conclusion, our study reveals that patients with NPH who respond positively to continuous slow lumbar cerebral spinal fluid drainage and receive a ventriculoperitoneal shunt implant, improve their performance on tasks of executive function. Due to the high demand for this form of mental processing in real-life complex scenarios, and based on the severe executive deficits present in both demented and non-demented NPH patients, we encourage the assessment of executive functions in this clinical group.

  6. Intraperitoneal cerebrospinal fluid pseudocyst. A rare complication of ventriculoperitoneal shunt.

    PubMed

    Birbilis, Th; Kontogianidis, K; Matis, G; Theodoropoulou, E; Efremidou, E; Argyropoulou, P

    2008-01-01

    The abdominal intraperitoneal cerebrospinal fluid pseudocyst is a rare but important complication in patients with ventriculoperitoneal shunts. We report a case of a 31-year-old female, in which a large abdominal pseudocyst was developed 1 year after insertion of a ventriculoperitoneal shunt for hydrocephalus. The abdominal CT scan and the ultrasonographical evaluation of the abdomen showed a well defined, cystic mass lesion with a volume of 50 cm3, in the recessus hepato-renal. The peritoneal tip of the shunt was located within the mass lesion. A distal externalization of the peritoneal catheter without excision of the pseudocyst was performed. Cerebrospinal fluid culture demonstrated a Staphylococcus epidermis infection and adequate antibiotic treatment was administrated. The previous symptoms improved 4 weeks later and a new catheter was placed intraperitoneally in a different quadrant. The postoperative course was uneventful. We suggest that chronic inflammation or subclinical peritonitis is a predisposing factor for this complication. PMID:18717287

  7. Delayed intracerebellar hemorrhage secondary to lumboperitoneal shunt insertion

    PubMed Central

    Er, Uygur; Akyol, Çetin; Bavbek, Murad

    2016-01-01

    Aim of this paper is to present and discuss a case of a delayed cerebellar parenchymal hemorrhage developing after L/P shunt placement with a NPH patient. A hypertensive patient admitted to our clinic with a diagnosis of NPH. The patient was placed a pressure adjustable L/P shunt without any surgical complication. He was discharged with an uneventful period. The patient was admitted to the emergency clinic of our hospital with a 1.5 × 1.5 cm diameter hematoma at the left cerebellar hemisphere on 2 days after his discharge. CSF drainage by an L/P shunt can generate intracerebellar hemorrhages especially in hypertensive patients. PMID:27695558

  8. Rare sequelae following ventriculoatrial shunt: Case report and review of literature

    PubMed Central

    Gopal, Vinu Venu; Peethambaran, Anil Kumar

    2016-01-01

    Ventriculoatrial shunt (VA) is one of the oldest solutions for hydrocephalus. However over subsequent years various complication of VA shunt such as obstructions, malposition, shunt infections, cardiac complications such as endocarditis, traumatic perforation, heart failure, tricuspid regurgitation, intraatrial thrombus, and pulmonary hypertension are reported. Hence, VA shunt procedure has fallen into disrepute. Still VA shunt may be a good option in selected patients with hostile peritoneum. Newer placement strategies and monitoring methods have been put forward to reduce complication following VA shunt. In this case report, we share a rare case of endocarditis with tricuspid regurgitation following a migrated retained calcified shunt tube in the right ventricle of heart 30 years after of VA shunt that was successfully managed. PMID:27057231

  9. Breast-related CSF shunt complications: literature review with illustrative case.

    PubMed

    Schrot, Rudolph J; Ramos-Boudreau, Christine; Boggan, James E

    2012-09-01

    In this article, we discuss and classify breast-related ventriculoperitoneal (VP) cerebrospinal fluid (CSF) shunt complications, and provide a literature review. Shunt complications related to pre-existing breast implants comprise nearly half of the breast-related shunt complications reported thus far. We present a complication of shunt failure in a 61-year-old woman who had previously undergone mastectomies for breast cancer with implant reconstruction. Following shunting, she developed headaches, fever, and right-sided breast swelling and erythma consequent to breast implant rupture, distal shunt migration, and CSF pseudocyst. This case is unique in that it involved rupture of a breast implant from VP shunt insertion. For complication avoidance, neurosurgeons should be aware of the potential pitfalls in shunting patients with breast implants.

  10. Time-related patterns of ventricular shunt failure.

    PubMed

    Kast, J; Duong, D; Nowzari, F; Chadduck, W M; Schiff, S J

    1994-11-01

    Proximal obstruction is reported to be the most common cause of ventriculoperitoneal (VP) shunt failure, suggesting that imperfect ventricular catheter placement and inadequate valve mechanisms are major causes. This study retrospectively examined patterns of shunt failure in 128 consecutive patients with symptoms of shunt malfunction over a 2-year period. Factors analyzed included site of failure, time from shunt placement or last revision to failure, age of patient at time of failure, infections, and primary etiology of the hydrocephalus. One hundred of these patients required revisions; 14 revisions were due to infections. In this series there was a higher incidence of distal (43%) than of proximal (35%) failure. The difference was not statistically significant when the overall series was considered; however, when factoring time to failure as a variable, marked differences were noted regardless of the underlying cause of hydrocephalus or the age of the patient. Of the 49 patients needing a shunt revision or replacement within 2 years of the previous operation, 50% had proximal malfunction, 14% distal, and 10% had malfunctions attributable directly to the valve itself. Also, 12 of the 14 infections occurred during this time interval. In sharp contrast, of the 51 patients having shunt failure from 2 to more than 12 years after the previous procedure, 72% had distal malfunction, 21% proximal, and only 6% had a faulty valve or infection. This difference between time to failure for proximal versus distal failures was statistically significant (P < 0.00001 for both Student's t-test and non-parametric Mann-Whitney U-test).(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Utility of Operative Glaucoma Tube Shunt Viscoelastic Bolus Flush

    PubMed Central

    Groth, Sylvia L; Greider, Kelsi L

    2015-01-01

    ABSTRACT Objective: To assess the utility of viscoelastic injection to induce bleb expansion and decrease intraocular pressure (IOP) in eyes with encapsulated glaucoma tube shunt blebs. Design: Case series. Subjects and participants: Forty-three glaucomatous eyes, including 13 eyes with congenital, 13 uveitic, 5 neovascular, 5 open angle, 4 narrow angle and 3 traumatic glaucomas. Methods, interventions or testing: All patients underwent viscoelastic flush procedure. A pre-bent 27 or 30-gauge cannula was passed through a 25-gauge paracentesis, advanced over the iris across the anterior chamber, and insinuated into the tube shunt lumen. Once the cannula was firmly lodged in position, 0.45 to 0.85 ml of viscoelastic was injected to hyperinflate the bleb. Main outcome measures: Paired t-tests were performed comparing preoperative IOP and number of medications used preoperatively vs levels measured at 1, 6, 12, 18 and 24 months. Results: Intraocular pressure was reduced from a mean preoperative level of 26.0 ± 1.2 (sem) mm Hg to 15.8 ± 1.0 at 1 month, remaining stable thereafter at each 6-month interval with 15.1 ± 1.1 mm Hg at 24 months (p < 0.0001). Medication use did not vary significantly from baseline. Pressure remained < 21 mm Hg after 2 years in 85% of eyes cannulated within 1 year of primary tube shunt implantation (n = 23), and in 62% of eyes cannulated more than 1 year after tube shunt placement (n = 20). Conclusion: Tube shunt expansion with bolus viscoelastic flush successfully restored encapsulated bleb function, providing a substantial (~10 mm Hg) IOP decrease into the mid-normal pressure range. This persisted in the majority of treated eyes for the entire study period. How to cite this article: Groth SL, Greider KL, Sponsel WE. Utility of Operative Glaucoma Tube Shunt Viscoelastic Bolus Flush. J Curr Glaucoma Pract 2015;9(3):73-76. PMID:26997840

  12. In Vitro and In Vivo Comparison of Two Suprachoroidal Shunts

    PubMed Central

    Oatts, Julius T.; Zhang, Ze; Tseng, Harry; Shields, M. Bruce; Sinard, John H.; Loewen, Nils A.

    2013-01-01

    Purpose. To compare fibrosis, aqueous humor dynamics, and intraocular pressure (IOP) of two suprachoroidal shunts as part of a new class of glaucoma drainage devices. Methods. Following proliferation analysis in vitro, 20 rabbits were implanted with either a gold shunt (GS, GMSplus+, SOLX) or a polypropylene shunt (PS, Aquashunt, OPKO). Ten eyes received mitomycin C (MMC) and triamcinolone. Peak and trough IOP were monitored with a pneumatonometer and tono-pen for 15 weeks. Aqueous humor dynamics were evaluated fluorophotometrically and tonographically. Fibrosis was quantified. Results. In vitro proliferation was similar. In vivo, both shunts were devoid of foreign body reaction but exhibited fibrosis, and GS showed vascularization. There was no significant difference in aqueous or uveoscleral flow. Preoperative morning IOP was 23.7 ± 2 mm Hg, and evening IOP was 26.5 ± 2 mm Hg (P = 0.000). Morning IOP was decreased through 15 weeks and evening IOP through 8 weeks in all groups. The morning IOP decrease was most profound at 15 weeks in PS (41%) compared to GS (18%). Antifibrotics initially enhanced but eventually diminished shunt performance. At 15 weeks, thickness of scleral fibrosis was greater in GS (246 ± 47 μm) and PS (188 ± 47 μm, P = 0.285) compared with GS+MMC (109 ± 26 μm, P = 0.023 to GS) and PS+MMC (48 ± 30 μm, P = 0.028 to PS). Conclusions. In a rabbit model, suprachoroidal polypropylene and gold shunts allow access to a new drainage pathway with different IOP profiles that can be modified with antifibrotics. PMID:23847318

  13. Shunted Piezoelectric Vibration Damping Analysis Including Centrifugal Loading Effects

    NASA Technical Reports Server (NTRS)

    Min, James B.; Duffy, Kirsten P.; Provenza, Andrew J.

    2011-01-01

    Excessive vibration of turbomachinery blades causes high cycle fatigue problems which require damping treatments to mitigate vibration levels. One method is the use of piezoelectric materials as passive or active dampers. Based on the technical challenges and requirements learned from previous turbomachinery rotor blades research, an effort has been made to investigate the effectiveness of a shunted piezoelectric for the turbomachinery rotor blades vibration control, specifically for a condition with centrifugal rotation. While ample research has been performed on the use of a piezoelectric material with electric circuits to attempt to control the structural vibration damping, very little study has been done regarding rotational effects. The present study attempts to fill this void. Specifically, the objectives of this study are: (a) to create and analyze finite element models for harmonic forced response vibration analysis coupled with shunted piezoelectric circuits for engine blade operational conditions, (b) to validate the experimental test approaches with numerical results and vice versa, and (c) to establish a numerical modeling capability for vibration control using shunted piezoelectric circuits under rotation. Study has focused on a resonant damping control using shunted piezoelectric patches on plate specimens. Tests and analyses were performed for both non-spinning and spinning conditions. The finite element (FE) shunted piezoelectric circuit damping simulations were performed using the ANSYS Multiphysics code for the resistive and inductive circuit piezoelectric simulations of both conditions. The FE results showed a good correlation with experimental test results. Tests and analyses of shunted piezoelectric damping control, demonstrating with plate specimens, show a great potential to reduce blade vibrations under centrifugal loading.

  14. Fetal ovarian cyst mimicking a CSF pseudocyst in the setting of shunt failure.

    PubMed

    Calayag, Mark; Malone, Christian Cantillano; Drake, Brian; Chavhan, Govind; Rutka, James T

    2015-01-01

    Fetal ovarian cysts are common congenital lesions encountered in the neonatal population. These cysts are typically benign and rarely require any invasive intervention. Abdominal pseudocyst formation as a result of a ventriculoperitoneal shunt is a relatively infrequent occurrence and is similarly an uncommon cause of shunt failure. The authors present the case of a 4-month-old girl with shunted hydrocephalus who presented with shunt failure from a suspected abdominal pseudocyst that was found to be a fetal ovarian cyst.

  15. Ventriculoperitoneal shunt complications in hydrocephalus patients with intracranial tumors: an analysis of relevant risk factors.

    PubMed

    Reddy, G Kesava; Bollam, Papireddy; Caldito, Gloria; Willis, Brian; Guthikonda, Bharat; Nanda, Anil

    2011-06-01

    Patients with intracranial tumors are predisposed to persistent hydrocephalus, often requiring a permanent CSF diversion procedure with shunts. This study reviews the long-term experience with ventriculoperitoneal shunts for the management of hydrocephalus in patients with intracranial tumors. Patients with intracranial tumors who underwent ventriculoperitoneal shunt placement for hydrocephalus from October 1990 to October 2009 were included in this study. During the 19-year period, medical charts, operative reports, imaging studies, and clinical follow- up evaluations were reviewed and analyzed retrospectively for all patients. A total of 187 intracranial tumor patients with hydrocephalus were included. The median follow up was 391 days. Malignant tumors were present in 40% of the patients. Overall shunt failure was 27.8%. Single shunt revision occurred in 13% of the patients and 14% had multiple shunt revision. Tumor histology, age and a procedure prior to shunt placement (ventriculostomy/Ommaya reservoirs) were significantly associated with the shunt revisions. Shunt system replacement and proximal shunt complication were significantly attributed to multiple shunt revisions. The overall shunt revision within 3 months, 6 months, 1 year and 5 years was 17.7%, 18.7%, 19.8% and 24.1%, respectively. The results of the study demonstrate that VP shunting is an effective for the management of hydrocephalus in patients with intracranial tumors. The overall incidence of shunt revision was 27.8%. Age, tumor histology, and a procedure prior to shunt placement (ventriculostomy/Ommaya reservoirs) were significantly associated with the shunt revisions. Additional studies using minimally invasive techniques are being explored for the management of hydrocephalus in patients with intracranial tumors.

  16. Treatment of Portosystemic Shunt Myelopathy with a Stent Graft Deployed through a Transjugular Intrahepatic Route

    SciTech Connect

    Jain, Deepak Arora, Ankur; Deka, Pranjal; Mukund, Amar Bhatnagar, Shorav; Jindal, Deepti Kumar, Niteen Pamecha, Viniyendra

    2013-08-01

    A case of surgically created splenorenal shunt complicated with shunt myelopathy was successfully managed by placement of a stent graft within the splenic vein to close the portosystemic shunt and alleviate myelopathy. To our knowledge, this is the first report of a case of shunt myelopathy in a patient with noncirrhotic portal fibrosis without cirrhosis treated by a novel technique wherein a transjugular intrahepatic route was adopted to deploy the stent graft.

  17. Endophthalmitis associated with Glaucoma Shunt Intraluminal Stent Exposure.

    PubMed

    Kwon, Hye Jin; Kerr, Nathan M; Ruddle, Jonathan B; Ang, Ghee Soon

    2016-01-01

    Endophthalmitis post glaucoma drainage implant (GDI) surgery is rare, often associated with tube or plate exposure. We report a case of endophthalmitis following glaucoma shunt intraluminal stent exposure in a patient who underwent Baerveldt glaucoma implant surgery. Endophthalmitis following manipulation of intraluminal stents is a rare complication of GDIs but potentially vision threatening condition that needs to be carefully screened for and treated immediately. How to cite this article: Kwon HJ, Kerr NM, Ruddle JB, Ang GS. Endophthalmitis associated with Glaucoma Shunt Intraluminal Stent Exposure. J Curr Glaucoma Pract 2016;10(1):36-37.

  18. CSF shunts 50 years on--past, present and future.

    PubMed

    Drake, J M; Kestle, J R; Tuli, S

    2000-11-01

    Cerebrospinal fluid (CSF) shunts were invented almost 50 years ago. While their introduction revolutionized the treatment of hydrocephalus, their complications have become legendary, and the focus of much investigation and development of new devices. New devices have been based upon improved understanding of the pathophysiology of hydrocephalus or shunt complications. Despite the rational, or frequently "more physiological," functioning of these devices, all too often unexpected complications have ensued, and the initial enthusiasm for the devices has waned. Assessing the efficacy of the devices has been difficult, owing to the lack of properly conducted studies. Nevertheless, the overall impact of shunt design improvements has seemed very limited. A recent randomized trial of CSF shunt design, examining the failure rates of two new and widely used valves (the Cordis Orbis Sigma and the Medtronic PS Medical Delta valves) failed to find any advantage of these over standard valve designs, many of which have been used almost since the inception of CSF shunts. A search for risk factors for failure, in a post hoc analysis of the data, indicated only that the etiology of the hydrocephalus and the position and local environment of the ventricular catheter tip were probably important. Remarkably, the rate of change in the size of the ventricles and the final ventricular size were not different despite the substantial differences in flow characteristics of the two new valves. Shunt failure rates of less than 5% at 1 year, with infection rates of less than 1%, seem like reasonable goals for the next decade in the new millenium. This can be achieved through basic research into the pathophysiology of shunt failure with improved mathematical models, and perhaps animal models of shunt failure. Efficacy of new devices or treatments must be scrutinized scientifically so as not to waste valuable resources and time on unproven treatments. Uncontrolled series and testimonial

  19. A Retrospective Analysis of Ventriculoperitoneal Shunt Revision Cases of a Single Institute

    PubMed Central

    Park, Man-Kyu; Kim, Myungsoo; Park, Ki-Su; Park, Seong-Hyun; Hwang, Jeong-Hyun

    2015-01-01

    Objective Ventriculoperitoneal (VP) shunt complication is a major obstacle in the management of hydrocephalus. To study the differences of VP shunt complications between children and adults, we analyzed shunt revision surgery performed at our hospital during the past 10 years. Methods Patients who had undergone shunt revision surgery from January 2001 to December 2010 were evaluated retrospectively by chart review about age distribution, etiology of hydrocephalus, and causes of revision. Patients were grouped into below and above 20 years old. Results Among 528 cases of VP shunt surgery performed in our hospital over 10 years, 146 (27.7%) were revision surgery. Infection and obstruction were the most common causes of revision. Fifty-one patients were operated on within 1 month after original VP shunt surgery. Thirty-six of 46 infection cases were operated before 6 months after the initial VP shunt. Incidence of shunt catheter fracture was higher in younger patients compared to older. Two of 8 fractured catheters in the younger group were due to calcification and degradation of shunt catheters with fibrous adhesion to surrounding tissue. Conclusion The complications of VP shunts were different between children and adults. The incidence of shunt catheter fracture was higher in younger patients. Degradation of shunt catheter associated with surrounding tissue calcification could be one of the reasons of the difference in facture rates. PMID:26113963

  20. Management for traumatic chronic subdural hematoma patients with well-controlled shunt system for hydrocephalus.

    PubMed

    Yamada, Shoko Mitrrt; Tomia, Yusuke; Murakami, Hideki; Nakane, Makoto

    2015-07-01

    Traumatic CSDH enlarged in two cases with VP or LP shunt system although the shunt valve pressure was increased to 200 mmH2O. In surgery, the hematoma cavity pressure was found to be 130 and 140 mmH2O, suggesting that to raise the shunt valve pressure is not effective for decreasing CSDH volume.

  1. Successful Embolization of a Spontaneous Mesocaval Shunt Using the Amplatzer Vascular Plug II

    SciTech Connect

    Boixadera, Helena; Tomasello, Alejandro; Quiroga, Sergi; Cordoba, Joan; Perez, Mercedes; Segarra, Antoni

    2010-10-15

    A 48-year-old man with alcoholic liver cirrhosis and hepatic encephalopathy was found to have a large, spontaneous mesocaval shunt. The shunt was successfully occluded with the use of an Amplatzer Vascular Plug. To our knowledge, this is the first report of the use of this device to embolize a mesocaval shunt involving the superior mesenteric vein.

  2. High-Flow Arterio-Hepatic Venous Shunt in Hepatocellular Carcinoma: Use of Multi-Electrode Radiofrequency for Shunt Obliteration

    SciTech Connect

    Pua, Uei

    2015-10-15

    Intra-tumoral arterio-hepatic venous shunting (AHVS) poses an impediment to transarterial chemoembolization of liver tumors. Not only does it present a potential hazard for systemic shunting and embolization, but also the altered flow dynamics may also result in poor delivery of drug/embolics to the target tumor bed. Current available techniques to overcome AVHS include arterial embolization (particles, coils, glue, etc.) or temporary venous occlusion using balloons. We hereby illustrate the use of radiofrequency ablation to obliterate a complex AHVS consisting of a varix-like venous aneurysm.

  3. Risk factors for shunt malfunction in pediatric hydrocephalus: a multicenter prospective cohort study.

    PubMed

    Riva-Cambrin, Jay; Kestle, John R W; Holubkov, Richard; Butler, Jerry; Kulkarni, Abhaya V; Drake, James; Whitehead, William E; Wellons, John C; Shannon, Chevis N; Tamber, Mandeep S; Limbrick, David D; Rozzelle, Curtis; Browd, Samuel R; Simon, Tamara D

    2016-04-01

    OBJECT The rate of CSF shunt failure remains unacceptably high. The Hydrocephalus Clinical Research Network (HCRN) conducted a comprehensive prospective observational study of hydrocephalus management, the aim of which was to isolate specific risk factors for shunt failure. METHODS The study followed all first-time shunt insertions in children younger than 19 years at 6 HCRN centers. The HCRN Investigator Committee selected, a priori, 21 variables to be examined, including clinical, radiographic, and shunt design variables. Shunt failure was defined as shunt revision, subsequent endoscopic third ventriculostomy, or shunt infection. Important a priori-defined risk factors as well as those significant in univariate analyses were then tested for independence using multivariate Cox proportional hazard modeling. RESULTS A total of 1036 children underwent initial CSF shunt placement between April 2008 and December 2011. Of these, 344 patients experienced shunt failure, including 265 malfunctions and 79 infections. The mean and median length of follow-up for the entire cohort was 400 days and 264 days, respectively. The Cox model found that age younger than 6 months at first shunt placement (HR 1.6 [95% CI 1.1-2.1]), a cardiac comorbidity (HR 1.4 [95% CI 1.0-2.1]), and endoscopic placement (HR 1.9 [95% CI 1.2-2.9]) were independently associated with reduced shunt survival. The following had no independent associations with shunt survival: etiology, payer, center, valve design, valve programmability, the use of ultrasound or stereotactic guidance, and surgeon experience and volume. CONCLUSIONS This is the largest prospective study reported on children with CSF shunts for hydrocephalus. It confirms that a young age and the use of the endoscope are risk factors for first shunt failure and that valve type has no impact. A new risk factor-an existing cardiac comorbidity-was also associated with shunt failure.

  4. Complications and subsequent removal of retained shunt hardware after endoscopic third ventriculostomy: case series.

    PubMed

    Pindrik, Jonathan; Jallo, George I; Ahn, Edward S

    2013-06-01

    This case series highlights multiple complications and subsequent removal of retained shunt hardware in pediatric patients after successful endoscopic third ventriculostomy (ETV). Removal or retention of existing shunt hardware following ETV represents an important dilemma. Prior studies have reported infections and organ perforation related to nonfunctioning shunts but none in the context of successful ETV. Data obtained in 3 children with hydrocephalus treated at the authors' institution were retrospectively reviewed after the patients experienced complications due to retained shunt hardware following ETV. Etiologies of hydrocephalus included tectal glioma and intraventricular hemorrhage. All 3 patients had a history of multiple shunt revisions and underwent urgent ETV in the setting of a shunt malfunction. In each case, the entire shunt system was left in situ, but it became the source of subsequent complications. Two of the 3 patients presented with the shunt infected by gram-negative bacilli 10 days and 4.5 months postoperatively, respectively. The remaining patient experienced wound dehiscence over the shunt valve 4.5 months after ETV. In all patients, the complications were managed successfully by removing the shunt hardware. None of the patients required repeat shunt insertion from the time of removal throughout the follow-up period (mean 24 months, range 9-36 months). During the study period, a total of 6 patients with indwelling shunt hardware underwent ETV with the expectation of being shunt independent. Among these 6 patients, 3 experienced no complications from the retained hardware whereas 3 patients (50%) ultimately experienced adverse consequences related to retained hardware. This case series illustrates complications involving retained shunt hardware after successful ETV. These examples support consideration of shunt removal at the time of ETV in the appropriate context.

  5. Comparison of passive inductor designs for piezoelectric shunt damping

    NASA Astrophysics Data System (ADS)

    Lossouarn, Boris; Thierry, Olivier; Aucejo, Mathieu; Deü, Jean-François

    2016-04-01

    Considering piezoelectric damping, a resonant shunt can lead to a significant vibration reduction when tuned to the mechanical mode to control. However, limits appear when looking at practical applications in a low frequency range: the required inductance is often too high to be satisfied with standard passive components. Moreover, even if the inductor is eventually available, the internal resistance of the component generally exceeds the value which is required for a shunt optimization. Suitable inductors can be designed for applications requiring high inductance and low resistance values. Indeed, the permeance of a magnetic circuit can be significantly increased by the use of closed cores made of high permeability materials. In this paper, three designs are described and compared: an inductor from standard series and two handmade inductors involving a ferrite core and a nanocrystalline toroid. The components are successively integrated into a piezoelectric shunt dedicated to the vibration control of a cantilever beam. Depending on the frequency of the target mechanical mode to control, the benefits and the limits of the different inductors are observed. It is shown that custom designs can definitely extend to lower frequency the application of the passive resonant shunt strategy.

  6. CONTEXT VIEW ALONG EXISTING PERIMETER TRACKS LOOKING TOWARDS SHUNTS IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CONTEXT VIEW ALONG EXISTING PERIMETER TRACKS LOOKING TOWARDS SHUNTS IN THEIR PRESENT-DAY POSITIONS, STORAGE SHED, AND MACHINE SHOP. LOOKING NORTHEAST. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  7. The Evolution of Transjugular Intrahepatic Portosystemic Shunt: Tips

    PubMed Central

    Fanelli, Fabrizio

    2014-01-01

    Since Richter's description in the literature in 1989 of the first procedure on human patients, transjugular intrahepatic portosystemic shunt (TIPS) has been worldwide considered as a noninvasive technique to manage portal hypertension complications. TIPS succeeds in lowering the hepatic sinusoidal pressure and in increasing the circulatory flow, thus reducing sodium retention, ascites recurrence, and variceal bleeding. Required several revisions of the shunt TIPS can be performed in case of different conditions such as hepatorenal syndrome, hepatichydrothorax, portal vein thrombosis, and Budd-Chiari syndrome. Most of the previous studies on TIPS procedure were based on the use of bare stents and most patients chose TIPS 2-3 years after traditional treatment, thus making TIPS appear to be not superior to endoscopy in survival rates. Bare stents were associated with higher incidence of shunt failure and consequently patients required several revisions during the follow-up. With the introduction of a dedicated e-PTFE covered stent-graft, these problems were completely solved, No more reinterventions are required with a tremendous improvement of patient's quality of life. One of the main drawbacks of the use of e-PTFE covered stent-graft is higher incidence of hepatic encephalopathy. In those cases refractory to the conventional medical therapy, a shunt reduction must be performed. PMID:27335841

  8. Shunt impedance measurement of the APS BBC injector.

    SciTech Connect

    Sun, Y.-E.; Lewellen, J. W.

    2006-01-01

    The injector test stand (ITS) at Advanced Photon Source (APS) presently incorporates a ballistic bunch compression (BBC) gun, and it is used as a beam source for a number of experiments, including THz generation, beam position monitor testing for the Linac Coherent Light Source (LCLS), novel cathode testing, and radiation therapy source development. The BBC gun uses three independently powered and phased rf cavities, one cathode cell, and two full cells to provide beam energies from 2 to 10 MeV with variable energy spread, energy chirp, and, to an extent, bunch duration. The shunt impedance of an rf accelerator determines how effectively the accelerator can convert supplied rf power to accelerating gradient. The calculation of the shunt impedance can be complicated if the beam energy changes substantially during its transit through a cavity, such as in a cathode cell. We present the results of direct measurements of the shunt impedance of the APS BBC gun on an individual cavity basis, including the cathode cell, and report on achieved gradients. We also present a comparison of the measured shunt impedance with theoretical values calculated from the rf models of the cavities.

  9. Ascites-induced LeVeen shunt coagulopathy.

    PubMed Central

    Ragni, M V; Lewis, J H; Spero, J A

    1983-01-01

    Ten of 11 patients undergoing peritoneovenous (LeVeen) shunt placement for intractable ascites had disseminated intravascular coagulation (DIC) following the shunt procedure. Intraoperative ascitic fluid specimens revealed fibrin split products (FSP) in high titer (1:100-1:1600) in all patients. Endotoxin was found in 6 of 11 ascitic fluid samples but in no plasma samples. Activated clotting factors, clot inhibitors, excess protein, and fibrinolytic activity were not found in ascitic fluid. Clotting factor levels were much lower than in plasma. Bleeding occurred after operation in two patients; this appeared to be related to the severity of liver dysfunction as demonstrated by elevations of bilirubin, serum glutamic oxalocetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), and preoperative DIC. It is concluded that the LeVeen shunt coagulopathy is DIC, and may be related to exposure of the systemic circulation to FSP-rich ascitic fluid that may activate the coagulation mechanism. Bleeding complications do not appear to be related to the severity of the post shunt coagulopathy, but rather to the severity of liver dysfunction and presence of preoperative DIC (probably caused by the liver disease). PMID:6859998

  10. Intra-hepatic vascular response to sodium nitrite

    PubMed Central

    Geumei, Aida; Issa, I.; Mahfouz, M.

    1969-01-01

    1. In the perfused liver of the dog, sodium nitrite produced vasoconstriction in the hepatic arterial bed and, particularly, in the portal venous vascular bed. 2. These effects on the hepatic vasculature may account in part for the reduction of venous return and diminution in cardiac output recorded by other workers, and may therefore be a factor in the clinical efficacy of the nitrites in angina pectoris. PMID:5809737

  11. Constipation as a reversible cause of ventriculoperitoneal shunt failure. Report of two cases.

    PubMed

    Powers, Ciaran J; George, Timothy; Fuchs, Herbert E

    2006-09-01

    Ventriculoperitoneal (VP) shunt failure is a common problem encountered by pediatric neurosurgeons. The majority of such failures are due to obstruction of the device. Conditions in which intraabdominal pressure is chronically elevated, such as pregnancy, have been associated with shunt failure. Chronic constipation may also result in abnormally elevated intraabdominal pressure and may be an underrecognized cause of distal VP shunt failure. The authors describe the cases of two children who presented with clinical and imaging evidence of VP shunt failure and who were also severely constipated. Treatment of their constipation resulted in both clinical and imaging-documented resolution of their shunt failure.

  12. Inferior vena cava stent grafting closure of a high-flow portacaval shunt.

    PubMed

    Alhaizaey, Abdullah; Ghanekar, Anand; Oreopoulos, George

    2016-01-01

    Portacaval (PC) shunts can be of congenital or acquired types. Acquired PC shunts are usually created in patients with end-stage liver disease to manage complications associated with portal hypertension or may be part of selected adult-adult living donor liver transplantation procedures to decrease the chance of the small-for-size syndrome. The main potential complication of these acquired high-flow PC shunts is early hepatic encephalopathy. We present a case of a high-flow acquired PC shunt after liver transplantation that was complicated by uncontrolled encephalopathy. This was treated by endovascular inferior vena cava stent grafting for shunt closure. PMID:26946901

  13. Pulmonary Arterial Hypertension Associated with Congenital Portosystemic Shunts Treated with Transcatheter Embolization and Pulmonary Vasodilators.

    PubMed

    Sato, Haruka; Miura, Masanobu; Yaoita, Nobuhiro; Yamamoto, Saori; Tatebe, Shunsuke; Aoki, Tatsuo; Satoh, Kimio; Ota, Hideki; Takase, Kei; Sugimura, Koichiro; Shimokawa, Hiroaki

    2016-01-01

    Cardiopulmonary abnormalities are often present in patients with liver diseases. We herein report a case of congenital portosystemic shunts complicated by hepatopulmonary syndrome (HPS) and portopulmonary hypertension (PoPH). A 57-year-old woman complained of dyspnea and was subsequently diagnosed with HPS and PoPH caused by congenital portosystemic shunts. Although shunt closure by transcatheter embolization was successfully performed, her dyspnea worsened and pulmonary artery pressure and pulmonary vascular resistance elevated. Conventional vasodilator therapy was started, resulting in an improvement of pulmonary hypertension (PH). In some patients with congenital portosystemic shunts, shunt closure could exacerbate PH, and vasodilator therapy may be effective. PMID:27580545

  14. Control of an electromechanical hydrocephalus shunt--a new approach.

    PubMed

    Elixmann, Inga M; Kwiecien, Monika; Goffin, Christine; Walter, Marian; Misgeld, Berno; Kiefer, Michael; Steudel, Wolf-Ingo; Radermacher, Klaus; Leonhardt, Steffen

    2014-09-01

    Hydrocephalus is characterized by an excessive accumulation of cerebrospinal fluid (CSF). Therapeutically, an artificial pressure relief valve (so-called shunt) is implanted which opens in case of increased intracranial pressure (ICP) and drains CSF into another body compartment. Today, available shunts are of a mechanical nature and drainage depends on the pressure drop across the shunt. According to the latest data, craniospinal compliance is considered to be even more important than mean ICP alone. In addition, ICP is not constant but varies due to several influences. In fact, heartbeat-related ICP waveform patterns depend on volume changes in the cranial vessels during a heartbeat and changes its shape as a function of craniospinal compliance. In this paper, we present an electromechanical shunt approach, which changes the CSF drainage as a function of the current ICP waveform. A series of 12 infusion tests in patients were analyzed and revealed a trend between the compliance and specific features of the ICP waveform. For waveform analysis of patient data, an existing signal processing algorithm was improved (using a Moore machine) and was implemented on a low-power microcontroller within the electromechanical shunt. In a test rig, the ICP waveforms were replicated and the decisions of the ICP analysis algorithm were verified. The proposed control algorithm consists of a cascaded integral controller which determines the target ICP from the measured waveform, and a faster inner-loop integral controller that keeps ICP close to the target pressure. Feedforward control using measurement data of the patient's position was implemented to compensate for changes in hydrostatic pressure during change in position. A model-based design procedure was used to lay out controller parameters in a simple model of the cerebrospinal system. Successful simulation results have been obtained with this new approach by keeping ICP within the target range for a healthy waveform.

  15. Experimental comparison of piezoelectric and magnetostrictive shunt dampers

    NASA Astrophysics Data System (ADS)

    Asnani, Vivake M.; Deng, Zhangxian; Scheidler, Justin J.; Dapino, Marcelo J.

    2016-04-01

    A novel mechanism called the vibration ring is being developed to enable energy conversion elements to be incorporated into the driveline of a helicopter or other rotating machines. Unwanted vibration is transduced into electrical energy, which provides a damping effect on the driveline. The generated electrical energy may also be used to power other devices (e.g., health monitoring sensors). PZT (`piezoceramic') and PMN-30%PT (`single crystal') stacks, as well as a Tb0.3Dy0.7Fe1.92 (`Terfenol-D') rod with a bias magnet array and a pickup coil, were tested as alternative energy conversion elements to use within the vibration ring. They were tuned for broadband damping using shunt resistors, and dynamic compression testing was conducted in a high-speed load frame. Energy conversion was experimentally optimized at 750Hz by tuning the applied bias stress and resistance values. Dynamic testing was conducted up to 1000Hz to determine the effective compressive modulus, shunt loss factor, internal loss factor, and total loss factor. Some of the trends of modulus and internal loss factor versus frequency were unexplained. The single crystal device exhibited the greatest shunt loss factor whereas the Terfenol-D device had the highest internal and total loss factors. Simulations revealed that internal losses in the Terfenol-D device were elevated by eddy current effects, and an improved magnetic circuit could enhance its shunt damping capabilities. Alternatively, the Terfenol-D device may be simplified to utilize only the eddy current dissipation mechanism (no pickup coil or shunt) to create broadband damping.

  16. Cerebrospinal fluid shunt infections. A review of 35 infections in 32 patients.

    PubMed

    Forward, K R; Fewer, H D; Stiver, H G

    1983-09-01

    The authors have reviewed the clinical manifestations and therapy of hydrocephalus shunt infections in 32 patients with a total of 35 shunt infections. These 35 infections accounted for 43 hospital admissions. First infections usually developed within 2 months following surgery. At the time of diagnosis, 89% of patients were febrile. Fever and cough as a symptom complex characterized the initial clinical presentation in six of 19 episodes of infection complicating ventriculoatrial (VA) shunts, as compared with none of 21 episodes in which infection complicated ventriculoperitoneal (VP) shunts. Seven of 21 infectious episodes occurring in patients with VP shunts in situ were associated with significant abdominal pain and tenderness. These patients usually had no other clinical features to suggest shunt infection. Both of these symptom complexes often led to delays in diagnosis and treatment. Causative organisms included Staphylococcus epidermidis in 21, Staphylococcus aureus in seven, Gram-negative aerobic bacilli in seven, diphtheroids in five, Streptococcus species in four, and anaerobes in three. Five infections were polymicrobial in nature. Positive blood cultures were seen in 13 of 17 infectious episodes complicating VA shunts, as compared with only three of 13 other infections. When the shunt was completely removed, with or without replacement, all 13 patients were cured. When intravenous antibiotics were administered in conjunction with incomplete shunt removal, only eight of 15 courses resulted in cure. Intraventricular antibiotics were administered in four patients and all were cured. Therapy of shunt infections with parenteral antibiotics and incomplete shunt removal is associated with an unacceptably high failure rate.

  17. Risk factors associated with distal catheter migration following ventriculoperitoneal shunt placement.

    PubMed

    Abode-Iyamah, Kingsley O; Khanna, Ryan; Rasmussen, Zachary D; Flouty, Oliver; Dahdaleh, Nader S; Greenlee, Jeremy; Howard, Matthew A

    2016-03-01

    Ventriculoperitoneal (VP) shunt placement is used to treat hydrocephalus. Shunt migration following VP shunt placement has been reported. The risk factors related to this complication have not been previously evaluated to our knowledge. In this retrospective cohort study, we aimed to determine risk factors leading to distal catheter migration and review the literature on the current methods of management and prevention. Adult patients undergoing VP shunt placement from June 2011 to December 2013 at a single institution were identified using electronic health records. The records were reviewed for demographic and procedural information, and subsequent treatment characteristics. The parameters of patients with distal shunt migration were compared to those undergoing new VP shunt placement for the same time period. We identified 137 patients undergoing 157 new VP shunt procedures with an average age of 57.7 ± standard deviation of 18.4 years old. There were 16 distal shunt migrations. Body mass index >30 kg/m(2) and number of previous shunt procedures were found to be independent risk factors for distal catheter migration. Obesity and number of previous shunt procedures were factors for distal catheter migration. Providers and patients should be aware of these possible risk factors prior to VP shunt placement.

  18. New and improved ways to treat hydrocephalus: Pursuit of a smart shunt

    PubMed Central

    Lutz, Barry R.; Venkataraman, Pranav; Browd, Samuel R.

    2013-01-01

    The most common treatment for hydrocephalus is placement of a cerebrospinal fluid shunt to supplement or replace lost drainage capacity. Shunts are life-saving devices but are notorious for high failure rates, difficulty of diagnosing failure, and limited control options. Shunt designs have changed little since their introduction in 1950s, and the few changes introduced have had little to no impact on these long-standing problems. For decades, the community has envisioned a “smart shunt” that could provide advanced control, diagnostics, and communication based on implanted sensors, feedback control, and telemetry. The most emphasized contribution of smart shunts is the potential for advanced control algorithms, such as weaning from shunt dependency and personalized control. With sensor-based control comes the opportunity to provide data to the physician on patient condition and shunt function, perhaps even by a smart phone. An often ignored but highly valuable contribution would be designs that correct the high failure rates of existing shunts. Despite the long history and increasing development activity in the past decade, patients are yet to see a commercialized smart shunt. Most smart shunt development focuses on concepts or on isolated technical features, but successful smart shunt designs will be a balance between technical feasibility, economic viability, and acceptable regulatory risk. Here, we present the status of this effort and a framework for understanding the challenges and opportunities that will guide introduction of smart shunts into patient care. PMID:23653889

  19. Role of SEP in identifying patients requiring temporary shunt during carotid endarterectomy.

    PubMed

    Fava, E; Bortolani, E; Ducati, A; Schieppati, M

    1992-01-01

    EEGs and short-latency somatosensory evoked potentials (SEPs) to median nerve stimulation were recorded during 151 carotid endarterectomies, performed under general anaesthesia. Carotid occlusion did not affect either EEG or SEP in 120 cases (group A). In 31 cases the EEG showed "ischaemic" abnormalities (group B). A temporary shunt was inserted only in 16 B patients showing also severely depressed cortical SEPs within 2 min after carotid occlusion (group B shunt). In 15 B patients in whom SEPs were less affected, the operation was completed without shunt (group B no shunt). One intraoperative stroke occurred in group A and two in group B shunt. No neurological complications occurred in group B no shunt. Overall stroke rate was 2%. On retrospective analysis, latency and amplitude of N20 and P25 waves proved to be uninfluenced by carotid occlusion in group A, but were significantly affected in group B shunt. P25 amplitude alone was reduced in B no shunt. An arbitrary index (need-for-shunt index, NSI) was made in order to rate changes of P25 latency and amplitude. Its mean values were significantly different in the 3 groups. A threshold value is suggested above which shunt is required, as a useful adjunct to EEG, in order to balance prevention of brain ischaemia against the risks of shunt.

  20. Fuzzy Inference System Approach for Locating Series, Shunt, and Simultaneous Series-Shunt Faults in Double Circuit Transmission Lines.

    PubMed

    Swetapadma, Aleena; Yadav, Anamika

    2015-01-01

    Many schemes are reported for shunt fault location estimation, but fault location estimation of series or open conductor faults has not been dealt with so far. The existing numerical relays only detect the open conductor (series) fault and give the indication of the faulty phase(s), but they are unable to locate the series fault. The repair crew needs to patrol the complete line to find the location of series fault. In this paper fuzzy based fault detection/classification and location schemes in time domain are proposed for both series faults, shunt faults, and simultaneous series and shunt faults. The fault simulation studies and fault location algorithm have been developed using Matlab/Simulink. Synchronized phasors of voltage and current signals of both the ends of the line have been used as input to the proposed fuzzy based fault location scheme. Percentage of error in location of series fault is within 1% and shunt fault is 5% for all the tested fault cases. Validation of percentage of error in location estimation is done using Chi square test with both 1% and 5% level of significance.

  1. Fuzzy Inference System Approach for Locating Series, Shunt, and Simultaneous Series-Shunt Faults in Double Circuit Transmission Lines

    PubMed Central

    Swetapadma, Aleena; Yadav, Anamika

    2015-01-01

    Many schemes are reported for shunt fault location estimation, but fault location estimation of series or open conductor faults has not been dealt with so far. The existing numerical relays only detect the open conductor (series) fault and give the indication of the faulty phase(s), but they are unable to locate the series fault. The repair crew needs to patrol the complete line to find the location of series fault. In this paper fuzzy based fault detection/classification and location schemes in time domain are proposed for both series faults, shunt faults, and simultaneous series and shunt faults. The fault simulation studies and fault location algorithm have been developed using Matlab/Simulink. Synchronized phasors of voltage and current signals of both the ends of the line have been used as input to the proposed fuzzy based fault location scheme. Percentage of error in location of series fault is within 1% and shunt fault is 5% for all the tested fault cases. Validation of percentage of error in location estimation is done using Chi square test with both 1% and 5% level of significance. PMID:26413088

  2. Peritoneovenous Shunt Insertion for Intractable Ascites-A District General Hospital Experience

    SciTech Connect

    Hussain, Fuad F. Meer, Ziad F.; Lopez, Anthony J.

    2004-08-15

    Ascites often contributes to patient morbidity and discomfort. When refractory to medical management, it has been managed with repeated paracentesis, implantable ports for drainage, or diversion to the urinary bladder. Peritoneovenous shunt insertion has been a technique that was traditionally performed only by surgeons but is now within the realm of interventional radiologists. Its advantage is that protein-rich ascitic fluid is returned to the intravascular compartment. This retrospective study elaborates on the successes and problems encountered during shunt insertion in our first 13 patients. Two patients are well with a functioning shunt at 14 and 32 weeks. In 6 the shunt functioned until the patients' death from the underlying malignancy. Two required revision with variable success and in 2, shunt function could not be salvaged. There was one procedure-related mortality. Radiological insertion of these shunts is feasible and should be considered for selected patients. Options are available for assessment and salvaging of dysfunctional shunts.

  3. Ventriculoperitoneal Shunt Complications In Children: An Evidence-Based Approach To Emergency Department Management.

    PubMed

    Bober, Jacqueline; Rochlin, Jonathan; Marneni, Shashidhar

    2016-02-01

    Although much is known about ventriculoperitoneal shunts, there are still large gaps in the literature and no evidence-based guidelines on management. To date, there is no general consensus on workup and treatment, and there are many differing diagnostic and therapeutic strategies for management of complications. Ventriculoperitoneal shunt complications can be separated into 3 categories: mechanical failure, infection, and functional failure. Knowing the basic anatomy of ventriculoperitoneal shunts, the time of shunt placement, and the clinical manifestations suggestive of potential complications can help with the management of patients with ventriculoperitoneal shunts. This review summarizes the literature on complications of ventriculoperitoneal shunts, examines the literature regarding the workup and management of patients with ventriculoperitoneal shunts, and makes recommendations for the management of these patients in the emergency department.

  4. Lumboatrial shunt in a patient with Crouzon syndrome complicated by pseudotumor cerebri.

    PubMed

    Sankey, Eric W; Khattab, Mohamed H; Elder, Benjamin D; Goodwin, C Rory; Rekate, Harold L; Rigamonti, Daniele

    2015-09-01

    A 25-year-old man with Crouzon syndrome complicated by pseudotumor cerebri and multiple shunt failures presented with progressive back and neck pain, intermittent headaches, and associated vomiting secondary to shunt infection. Due to his previous history of repeated failure of both ventriculoperitoneal and lumboperitoneal (LP) shunting procedures, the decision was made to place a lumboatrial (LA) shunt via an approach through the internal jugular vein. The procedure was uncomplicated and the man's symptoms were relieved. Despite significant improvement, the LA shunt limited his exercise tolerance, and as an avid runner and weight lifter, he requested reconversion back to an LP shunt. At a follow-up of 20months, he continued to do well both clinically and radiographically. This case report summarizes the successful placement and use of an LA shunt for the treatment of intracranial hypertension in the setting of Crouzon syndrome. PMID:26021731

  5. Systemic-pulmonary artery shunts in infants: modified Blalock-Taussig and central shunt procedures.

    PubMed

    Brooks, Andre

    2014-01-01

    Access is gained through a midline sternotomy, the thymus partially excised and the superior part of the pericardium is opened. The innominate vein is retracted and the innominate artery is mobilized up to the bifurcation. The aorta is retracted to the left, the superior vena cavae to the right and the right atrial appendage inferiorly. The adventitia around the right pulmonary artery (PA) is dissected, taking care to incise the bulky pericardial reflection between the superior vena cavae and the trachea. Heparin is administrated. An occlusive clamp is applied to the right PA to test for haemodynamic tolerance prior to proceeding with the interposition of a suitable size artificial vascular prosthesis, based on the weight of the patient, between the innominate artery, or proximal subclavian artery and the right PA. Alternatively, if a sufficient main PA is present and adequate flow from a patent ductus arteriosus an end-to-side interposition shunt may be constructed between the ascending aorta and the main PA, provided the patient is stable with the test occlusion of the main PA. The management of the patent arterial ductus depends on whether or not there is forward flow through the PA.

  6. Assessment of surgical portosystemic shunts and associated complications: The diagnostic and therapeutic role of radiologists.

    PubMed

    Taslakian, Bedros; Faraj, Walid; Khalife, Mohammad; Al-Kutoubi, Aghiad; El-Merhi, Fadi; Saade, Charbel; Hallal, Ali; Haydar, Ali

    2015-08-01

    Surgical portosystemic shunting, the formation of a vascular connection between the portal and systemic venous circulation, has been used as a treatment to reduce portal venous pressure. Although the use of portosystemic shunt surgery in the management of portal hypertension has declined during the past decade in favour of alternative therapies, and subsequently surgeons and radiologists became less familiar with the procedure, it remains a well-established treatment. Knowledge of different types of surgical portosystemic shunts, their pathophysiology and complications will help radiologists improve communication with surgeons and enhance their understanding of the diagnostic and therapeutic role of radiology in the assessment and management of these shunts. Optimal assessment of the shunt is essential to determine its patency and allow timely intervention. Both non-invasive and invasive imaging modalities complement each other in the evaluation of surgical portosystemic shunts. Interventional radiology plays an important role in the management of complications, such as shunt thrombosis and stenosis. This article describes the various types of surgical portosystemic shunts, explains the anatomy and pathophysiology of these shunts, illustrates the pearls and pitfalls of different imaging modalities in the assessment of these shunts and demonstrates the role of radiologists in the interventional management of complications.

  7. Listeria monocytogenes: a rare complication of ventriculoperitoneal shunt in children.

    PubMed

    Le Monnier, Alban; Blanot, Stéphane; Abachin, Eric; Beretti, Jean-Luc; Berche, Patrick; Kayal, Samer

    2011-11-01

    We report a case of ventriculoperitoneal (VP) shunt infection in a 3-year-old boy caused by the food-borne pathogen Listeria monocytogenes, subsequent to acute peritonitis. This unusual presentation of central nervous system (CNS) listeriosis underlines the ability of the bacteria to form and survive within biofilms on indwelling medical devices. Bacterial persistence may lead to treatment failure and spreading. We highlight the helpfulness of specific quantitative real-time PCR for the hly gene (PCR-hly) for the diagnosis and follow-up of such infections in detecting bacterial persistence within medical devices despite effective antibiotic treatment. Only the surgical replacement of the VP shunt will resolve the infection.

  8. Growth of basilar artery aneurysm after ventriculo-peritoneal shunt.

    PubMed

    Kim, Myoung Soo; Oh, Chang-Wan; Han, Dae Hee

    2002-11-01

    We report upon two cases of obstructive hydrocephalus produced by giant basilar artery aneurysms. They initially presented with symptoms of increased intracranial pressure, and were managed by a ventriculo-peritoneal (VP) shunt with good symptomatic improvement. With time, however, both showed a gradual deterioration of clinical symptoms due to increased aneurysm size. One, with a basilar tip aneurysm was treated by direct neck-clipping of the aneurysm, and was able to return to work. In the other patient, with a basilar trunk aneurysm, endovascular occlusion of one vertebral artery was attempted in an effort to decrease the aneurysm size, but the aneurysm enlarged precipitating brain stem failure. In conclusion, these cases reveal the risk of the VP shunt, which may induce aneurysmal growth, leading to clinical devastation, and emphasize the importance of definitive treatment for giant cerebral aneurysms whenever possible.

  9. Protein adsorption to hydrocephalus shunt catheters: CSF protein adsorption

    PubMed Central

    Brydon, H.; Keir, G.; Thompson, E.; Bayston, R.; Hayward, R.; Harkness, W.

    1998-01-01

    OBJECTIVE—To assess the quantity and nature of the proteins that adsorb to hydrocephalus shunt catheters after implantation, and to determine whether sufficient could accumulate to obstruct the catheter.
DESIGN—Elution of proteins from 102 explanted shunt catheters, with protein assay and electrophoresis of the eluate, and scanning electron microscopy (SEM) of the catheters.
RESULTS—The amount of protein elutable was extremely low, and significant protein, apart from a thin film, was not found on SEM. Qualitative analysis disclosed that most of the adsorbed protein was albumin.
CONCLUSIONS—Protein deposition on hydrocephalus catheters does not occur in sufficient quantities to cause catheter obstruction.

 PMID:9598681

  10. Anal extrusion of a ventriculo peritoneal shunt tube: Endoscopic removal.

    PubMed

    Vuyyuru, Sreedhar; Ravuri, Sreenivas R; Tandra, Vamsidhar R; Panigrahi, Manas K

    2009-07-01

    We describe the extrusion of a ventriculo peritoneal shunt tube from the anus into a 6-year-old boy following the placement of a ventriculo peritoneal shunt for postoperative periventricular tumor-induced hydrocephalus. He was admitted with a complaint of extrusion of a tube through anus on and off during bowel evacuation. He was evaluated with an X-ray of the abdomen which was showing a coiled tube in descending and sigmoid colon, confirmed by sigmoidoscopy. The proximal end was exposed for external ventricular drainage and distal end was removed endoscopically. The patient was watched for peritonitis and managed conservatively. The proximal end of the tube was removed after 5 days of external ventricular drainage and after ruling out ventriculitis and meningitis. Bowel perforation by a ventriculo peritoneal tube is a rare complication. Diagnosis is often difficult and delayed. Most of the bowel perforation is seen in young patients. PMID:21887196

  11. Emergency Portacaval Shunt Versus Rescue Portacaval Shunt in a Randomized Controlled Trial of Emergency Treatment of Acutely Bleeding Esophageal Varices in Cirrhosis—Part 3

    PubMed Central

    Isenberg, Jon I.; Wheeler, Henry O.; Haynes, Kevin S.; Jinich-Brook, Horacio; Rapier, Roderick; Vaida, Florin; Hye, Robert J.

    2010-01-01

    Background Emergency treatment of bleeding esophageal varices in cirrhosis is of singular importance because of the high mortality rate. Emergency portacaval shunt is rarely used today because of the belief, unsubstantiated by long-term randomized trials, that it causes frequent portal-systemic encephalopathy and liver failure. Consequently, portacaval shunt has been relegated solely to salvage therapy when endoscopic and pharmacologic therapies have failed. Question: Is the regimen of endoscopic sclerotherapy with rescue portacaval shunt for failure to control bleeding varices superior to emergency portacaval shunt? A unique opportunity to answer this question was provided by a randomized controlled trial of endoscopic sclerotherapy versus emergency portacaval shunt conducted from 1988 to 2005. Methods Unselected consecutive cirrhotic patients with acute bleeding esophageal varices were randomized to endoscopic sclerotherapy (n = 106) or emergency portacaval shunt (n = 105). Diagnostic workup was completed and treatment was initiated within 8 h. Failure of endoscopic sclerotherapy was defined by strict criteria and treated by rescue portacaval shunt (n = 50) whenever possible. Ninety-six percent of patients had more than 10 years of follow-up or until death. Results Comparison of emergency portacaval shunt and endoscopic sclerotherapy followed by rescue portacaval shunt showed the following differences in measurements of outcomes: (1) survival after 5 years (72% versus 22%), 10 years (46% versus 16%), and 15 years (46% versus 0%); (2) median post-shunt survival (6.18 versus 1.99 years); (3) mean requirements of packed red blood cell units (17.85 versus 27.80); (4) incidence of recurrent portal-systemic encephalopathy (15% versus 43%); (5) 5-year change in Child’s class showing improvement (59% versus 19%) or worsening (8% versus 44%); (6) mean quality of life points in which lower is better (13.89 versus 27.89); and (7) mean cost of care per

  12. Could there be light at the end of the tunnel? Mesocaval shunting for refractory esophageal varices in patients with contraindications to transjugular intrahepatic portosystemic shunt

    PubMed Central

    Davis, Jessica; Chun, Albert K; Borum, Marie L

    2016-01-01

    Cirrhotic patients with recurrent variceal bleeds who have failed prior medical and endoscopic therapies and are not transjugular intrahepatic portosystemic shunt candidates face a grim prognosis with limited options. We propose that mesocaval shunting be offered to this group of patients as it has the potential to decrease portal pressures and thus decrease the risk of recurrent variceal bleeding. Mesocaval shunts are stent grafts placed by interventional radiologists between the mesenteric system, most often the superior mesenteric vein, and the inferior vena cava. This allows flow to bypass the congested hepatic system, reducing portal pressures. This technique avoids the general anesthesia and morbidity associated with surgical shunt placement and has been successful in several case reports. In this paper we review the technique, candidate selection, potential pitfalls and benefits of mesocaval shunt placement. PMID:27429715

  13. Could there be light at the end of the tunnel? Mesocaval shunting for refractory esophageal varices in patients with contraindications to transjugular intrahepatic portosystemic shunt.

    PubMed

    Davis, Jessica; Chun, Albert K; Borum, Marie L

    2016-07-01

    Cirrhotic patients with recurrent variceal bleeds who have failed prior medical and endoscopic therapies and are not transjugular intrahepatic portosystemic shunt candidates face a grim prognosis with limited options. We propose that mesocaval shunting be offered to this group of patients as it has the potential to decrease portal pressures and thus decrease the risk of recurrent variceal bleeding. Mesocaval shunts are stent grafts placed by interventional radiologists between the mesenteric system, most often the superior mesenteric vein, and the inferior vena cava. This allows flow to bypass the congested hepatic system, reducing portal pressures. This technique avoids the general anesthesia and morbidity associated with surgical shunt placement and has been successful in several case reports. In this paper we review the technique, candidate selection, potential pitfalls and benefits of mesocaval shunt placement. PMID:27429715

  14. Results of Trabectome Surgery Following Failed Glaucoma Tube Shunt Implantation

    PubMed Central

    Mosaed, Sameh; Chak, Garrick; Haider, Asghar; Lin, Ken Y.; Minckler, Don S.

    2015-01-01

    Abstract To evaluate the safety and efficacy of Trabectome after failed tube shunt surgery. Twenty patients with prior failed tube shunt surgery who underwent Trabectome alone were included. All patients had at least 3 months of follow-up. Outcomes measured included intraocular pressure (IOP), glaucoma medications, and secondary glaucoma surgeries. The success for Kaplan–Meier survival analysis is defined as IOP ≤21 mm Hg, IOP reduced by at least 20% from preoperative IOP, and no secondary glaucoma surgery. Mean preoperative IOP was 23.7 ± 6.4 mm Hg and mean number of glaucoma medications was 3.2 ± 1.5. At 12 months, IOP was reduced to 15.5 ± 3.2 mm Hg (P = 0.05) and number of medications was reduced to 2.4 ± 1.5 (P = 0.44). Survival rate at 12 months was 84% and 3 patients required additional glaucoma surgery with 15 patients reaching 12 months follow-up. Other than failure of IOP control and transient hypotony (IOP < 3 mm Hg) day 1 in 2 cases, there were no adverse events. Trabecular bypass procedures have traditionally been considered an approach appropriate for early-to-moderate glaucoma; however, our study indicates benefit in refractory glaucoma as well. Eyes that are prone to conjunctival scarring and hypertrophic wound healing, such as those who have failed tube shunt surgery, may benefit from procedures that avoid conjunctival incision such as Trabectome. This study indicates potential benefits in this patient population. Trabectome was safe and effective in reducing IOP at 1-year follow-up in patients with prior failed tube shunt surgery, but not effective in reducing medication reliance in these patients. PMID:26222842

  15. Congenital intrahepatic portosystemic shunts: Imaging findings and endovascular management

    PubMed Central

    Chandrasekharan, Rajsekar; Pullara, Sreekumar K; Thomas, Tixon; Kader, Nazar Puthukudiyil; Moorthy, Srikanth

    2016-01-01

    We present two cases of congenital intrahepatic portosystemic shunts in which the right portal vein directly communicated with the inferior venacava (IVC) in one patient and with the hepatic vein in the other. Multiple hepatic nodules consistent with focal nodular hyperplasia (FNH) were seen in the first patient. The second patient presented with recurrent history of hepatic encephalopathy. Percutaneous transhepatic embolization was performed using coils and Amplatz device following which she completely recovered. PMID:27081230

  16. Resonance features of coupled Josephson junctions: radiation and shunting

    NASA Astrophysics Data System (ADS)

    Shukrinov, Yu M.; Seidel, P.; Il'ichev, E.; Nawrocki, W.; Grajcar, M.; Plecenik, P. A.; Rahmonov, I. R.; Kulikov, K.

    2012-11-01

    We study the phase dynamics and the resonance features of coupled Josephson junctions in layered superconductors and their manifestations in the current- voltage characteristics and temporal dependence of the electric charge in the superconducting layers. Results on the effect of the external radiation and shunting of the stack of Josephson junctions by LC-elements are presented. We discuss the ideas concerning the experimental observation of these resonances.

  17. Modified Blalock-Taussig Shunt with an Umbilical Vein Graft

    PubMed Central

    Leão, Luiz Eduardo V.; Andrade, José Carlos S.; Succi, José Ernesto; Cueva, Clotario C.; Ribeiro, Expedito E.; Carvalho, Antonio Carlos C.; Buffolo, Enio

    1985-01-01

    We describe a modification of the Blalock Taussig anastomosis, with the interposition of a glutaraldehyde-tanned umbilical vein graft between the subclavian and pulmonary arteries. This operation was performed in 64 children: 11 were less than 1 month of age (17.2%), and 23 were between 1 and 6 months of age (34.9%). Hospital deaths occurred in six patients—all less than 6 months of age (9.4%). There was no instance of shunt occlusion noted. The clinical course was uneventful among survivors, except for one patient who died of endocarditis in the late postoperative follow-up. The shunt procedure may be performed very rapidly, with minimal dissection, allowing the use of a graft larger than the diameter of the subclavian artery. This modification of the Blalock Taussig operation compares favorably with our previous experience with other shunt procedures and may be considered a valuable alternative in the palliative surgical treatment of several malformations with severe pulmonary oligemia. Images PMID:15227043

  18. Hysteresis Control for Current Harmonics Suppression Using Shunt Active Filter

    NASA Astrophysics Data System (ADS)

    Ahuja, Rajesh Kr; Chauhan, Aasha; Sharma, Sachin

    2012-11-01

    Recently wide spread of power electronic equipment has caused an increase of the harmonic disturbances in the power systems. The nonlinear loads draw harmonic and reactive power components of current from ac mains. Current harmonics generated by nonlinear loads such as adjustable speed drives,static powersupplies and UPS. Thus a perfect compensator is required to avoid the consequences due to harmonics. To overcome problems due to harmonics, Shunt Active Power Filter (SAPF) has been considered extensively. SAPF has better harmonic compensation than the other approaches used for solving the harmonic related problems. The performance of the SAPF depends upon different control strategies. This paper presents the performance analysis of SAPF under most important control strategy namely instantaneous real active and reactive power method (p-q) for extracting reference currents of shunt active filters under unbalanced load condition. Detailed simulations have been carried out considering this control strategy and adequate results were presented. In this paper, harmonic control strategy is applied to compensate the current harmonics in the system. A detailed study about the harmonic control method has been used using shunt active filter technique.

  19. Depiction of ventriculoperitoneal shunt obstruction with single-photon emission computed tomography/computed tomography

    PubMed Central

    Aksoy, Sabire Yılmaz; Vatankulu, Betül; Uslu, Lebriz; Halac, Metin

    2016-01-01

    An 83-year-old male patient with ventriculoperitoneal shunt underwent radionuclide shunt study using single-photon emission computed tomography/computed tomography (SPECT/CT) to evaluate the shunt patency. The planar images showed activity at the cranial region and spinal canal but no significant activity at the peritoneal cavity. However, SPECT/CT images clearly demonstrated accumulation of activity at the superior part of bifurcation level with no activity at the distal end of shunt as well as no spilling of radiotracer into the peritoneal cavity indicating shunt obstruction. SPECT/CT makes the interpretation of radionuclide shunt study more accurate and easier as compared with traditional planar images. PMID:27385906

  20. Infection as a cause of peritoneal catheter dysfunction in ventriculo-peritoneal shunting in children.

    PubMed

    Frykberg, T; Olden, L

    1983-12-01

    Peritoneal catheter dysfunction is a significant complication of VP shunting in children. Improvement in technique and material should reduce complications such as detachment and breakage. Shunt infection, even if subclinical, should be suspected as the cause of early peritoneal catheter obstruction, especially if recurrent, as well as in cases of organ perforation. Cultures, prolonged if necessary, should be taken and infection should be treated prior to shunt revision. We have had no recurrence of infection or peritoneal catheter dysfunction after treatment with exteriorization of the infected shunt, antibiotic therapy and insertion of a new shunt on the contralateral side. In infected cases antibiotic therapy, both pre- and intra-operatively, should be a matter of course. With these precautions a better result with the ventriculo-peritoneal shunt should be achieved.

  1. Chemoembolic Hepatopulmonary Shunt Reduction to Allow Safe Yttrium-90 Radioembolization Lobectomy of Hepatocellular Carcinoma

    SciTech Connect

    Gaba, Ron C.; VanMiddlesworth, Kyle A.

    2012-12-15

    Yttrium-90 ({sup 90}Y) radioembolization represents an emerging transcatheter treatment option for the management of hepatocellular carcinoma (HCC). Elevation of the hepatopulmonary shunt fraction risks nontarget radiation to the lungs and may limit the use of {sup 90}Y therapy in patients with locally advanced disease with vascular invasion, who often demonstrate increased shunting. We present two cases in which patients with HCC and portal vein invasion resulting in elevated hepatopulmonary shunt fractions underwent chemoembolic shunt closure to allow safe {sup 90}Y radioembolization. Both patients demonstrated excellent tumor response and patient survival. On this basis, we propose a role for chemoembolic reduction of the lung shunt fraction before {sup 90}Y radioembolization in patients with extensive tumor-related hepatopulmonary shunting.

  2. Development of chronic hepatocerebral degeneration eight years after a distal splenorenal (Warren) shunt.

    PubMed Central

    Bleasel, A F; Waugh, R C; McCaughan, G W

    1989-01-01

    It is well known that chronic encephalopathy may be a major complication after the establishment of a surgical portal caval shunt for an episode of variceal haemorrhage. In an effort to minimise this problem Warren and colleagues developed the distal splenorenal shunt where the portal and mesenteric blood flow to the liver was left intact. It is now recognised, however, that the longterm incidence of encephalopathy may be no different with this type of shunt compared with conventional surgical portal systemic shunts. Acquired chronic hepatocerebral degeneration has not been reported after such a selective shunt. A patient with primary biliary cirrhosis is reported who developed the clinical features of this syndrome eight years after a successful distal splenorenal shunt. Images Fig. 1 Fig. 2 PMID:2583570

  3. A multi-stack simulation of shunt currents in vanadium redox flow batteries

    NASA Astrophysics Data System (ADS)

    Wandschneider, F. T.; Röhm, S.; Fischer, P.; Pinkwart, K.; Tübke, J.; Nirschl, H.

    2014-09-01

    A model for the shunt currents in an all-vanadium redox flow battery consisting of 3 stacks which are electrically connected in series. It is based on an equivalent circuit which treats the shunt current pathways as Ohmic resistors. The conductivity of the vanadium electrolyte has been measured for different state-of-charges in order to implement a dependency of the resistances on the state-of-charge of the system. Published results are used to validate the simulation data of a single stack. Three setups of pipe networks are evaluated using the model. The pipe connections between the stacks give rise to external shunt currents, which also increase the amount of shunt currents within the stacks. These connections also lead to a nonuniform distribution of the shunt currents. The effects of the shunt currents on the Coulombic efficiency and the energy efficiency of the system are studied by the means of the model.

  4. Transjugular intrahepatic portosystemic shunt combined with esophagogastric variceal embolization in the treatment of a large gastrorenal shunt

    PubMed Central

    Jiang, Qin; Wang, Ming-Quan; Zhang, Guo-Bing; Wu, Qiong; Xu, Jian-Ming; Kong, De-Run

    2016-01-01

    AIM: To evaluate the efficacy and safety of transjugular intrahepatic portosystemic shunt (TIPS) combined with stomach and esophageal variceal embolization (SEVE) in cirrhotic patients with a large gastrorenal vessel shunt (GRVS). METHODS: Eighty-one cirrhotic patients with gastric variceal bleeding (GVB) associated with a GRVS were enrolled in the study and accepted TIPS combined with SEVE (TIPS + SEVE), by which portosystemic pressure gradient (PPG), biochemical, TIPS-related complications, shunt dysfunction, rebleeding, and death were evaluated. RESULTS: The PPGs before TIPS were greater than 12 mmHg in 81 patients. TIPS + SEVE treatment caused a significant decrease in PPG (from 37.97 ± 6.36 mmHg to 28.15 ± 6.52 mmHg, t = 19.22, P < 0.001). The percentage of reduction in PPG was greater than 20% from baseline. There were no significant differences in albumin, alanine aminotransferase, aspartate aminotransferase, bilirubin, prothrombin time, or Child-Pugh score before and after operation. In all patients, rebleeding rates were 3%, 6%, 12%, 18%, and 18% at 1, 3, 6, 12, and 18 mo, respectively. Five patients (6.2%) were diagnosed as having hepatic encephalopathy. The rates of shunt dysfunction were 0%, 4%, 9%, 26%, and 26%, at 1, 3, 6, 12, and 18 mo, respectively. The cumulative survival rates in 1, 3, 6, 12, and 18 mo were 100%, 100%, 95%, 90%, and 90%, respectively. CONCLUSION: Our preliminary results indicated that the efficacy and safety of TIPS + SEVE were satisfactory in cirrhotic patients with GVB associated with a GRVS (GVB + GRVS). PMID:27458505

  5. CSF hydrothorax without intrathoracic catheter migration in children with ventriculoperitoneal shunt

    PubMed Central

    Kim, Joon-Hyung; Roberts, David W.; Bauer, David F.

    2015-01-01

    Background: Thoracic complications of ventriculoperitoneal (VP) shunts have been extensively reported in the literature. Cerebrospinal fluid (CSF) hydrothorax without catheter migration, however, has been rarely described and poorly understood. Case Description: We describe development of pleural effusion and respiratory distress in a 3-year-old boy with no evidence of VP shunt catheter displacement on plain radiograph and stable ventricle size on rapid sequence magnetic resonance imaging (MRI) brain. Chest X-ray revealed complete opacity of right hemithorax. Pleural effusion was consistent with transudate. Beta-2 transferrin returned positive. The patient underwent externalization of VP shunt, and upon resolution of effusion, re-internalization with new distal shunt catheter. A literature review of CSF hydrothorax in children without intrathoracic shunt migration was performed. Eleven cases were identified in the English literature. Age at VP shunt placement ranged from birth to 8 years of age. Interval from VP shunt placement to CSF hydrothorax ranged from 1.5 months to 5 years. History of shunt revision was reported in two cases. Presenting symptoms also included ascites and inguinal hernia or hydrocele. Reported diagnostic studies consist of CSF culture, radionuclide shuntogram, beta-2 transferrin, and beta-trace protein. Laterality of the VP shunt and development of pleural effusion were predominantly right sided. Definitive surgical treatment included VA shunt, repositioning of the peritoneal catheter, and endoscopic choroid plexus coagulation. Conclusion: CSF hydrothorax is a rare thoracic complication of VP shunt placement with no radiographic evidence of shunt migration or malfunction. Postulated mechanisms include limited peritoneal capacity to resorb CSF in children and microscopic communications present in congenital diaphragmatic hiatuses. PMID:26236552

  6. The complementary role of plain radiographs and radionuclide shuntography in evaluating CSF-VP shunts.

    PubMed

    Blair, K; AuCoin, R; Kloiber, R; Molnar, C P

    1989-02-01

    Cerebrospinal fluid-ventriculoperitoneal shunts are often used in the treatment of hydrocephalus in children. Many complications can arise that may lead to shunt malfunction, including detachment of the distal limb of the shunt. A case is presented where such a complication occurred with distal migration of the detached tubing into the abdomen, which resulted in a patent subcutaneous tract through which cerebrospinal fluid could drain. The need for radiographic correlation at the time of radionuclide shuntography is stressed.

  7. Treatment and microbiology of repeated cerebrospinal fluid shunt infections in children

    PubMed Central

    Tuan, Teresa J; Thorell, Emily A; Hamblett, Nicole Mayer; Kestle, John R. W.; Rosenfeld, Margaret; Simon, Tamara D

    2011-01-01

    Background A small group of children have second and even more cerebrospinal fluid (CSF) shunt infections (SI). We sought to describe the treatment approaches used for, and the microbiology of, repeated shunt infections. Methods The study population included 31 children with second shunt infection (SI-2) among those undergoing initial CSF shunt placement and treatment for initial infection at Primary Children’s Medical Center. CSF shunt infection was defined as: 1) presence of bacteria in Gram stain and/or culture of CSF, wound, and/or pseudocyst; 2) visible hardware; or 3) abdominal pseudocyst; or (4) presence of bacteria in a blood culture in children with a ventriculoatrial shunt. Infection rates were generated using per-patient denominators, and the concordance of organisms across infections was summarized. Results Of the 31 children with SI-2, most were less than 6 months of age at initial shunt placement (81%), male (77%), and with ventriculoperitoneal shunts (71%). Eighteen developed SI-3 and 8 developed SI-4. Infection rates were 60% (95% confidence interval (CI): 42–75%, n=18/30) for SI-3 and 47% (95% CI: 26–69%, n=8/17) for SI-4. The median time to SI-3 was 477 days (range 5–828) and to SI-4 was 2137 days (range 9–2137). Gram-positive organisms predominated (93% of SI-2, 94% of SI-3). The majority of second shunt infections demonstrated Gram-stain concordance with both the initial (first) shunt infection (58%, 95% CI: 41–74%) and with the following (third) shunt infection (78%, 95% CI: 55–91%). Conclusions Children with second shunt infection experience high subsequent re-infection rates with a long time to re-infection. PMID:21852762

  8. Reversibility of intrapulmonary arteriovenous shunts in liver cirrhosis documented by serial radionuclide perfusion lung scans

    SciTech Connect

    Chen, N.S.; Barnett, C.A.; Farrer, P.A.

    1984-05-01

    Using serial perfusion lung scans, the opening up and closure of right-to-left intrapulmonary arteriovenous shunts has been documented over a period of several weeks in a patient with chronic alcoholic liver disease. The presence of the shunts correlates well with the severity of hypoxemia and the presence of nodular mottling on chest radiographs. The time course of these changes with clinical status suggests lability and the functional nature of these shunts.

  9. Gold shunt for refractory advanced low-tension glaucoma with spared central acuity

    PubMed Central

    Le, Ryan; Gupta, Neeru

    2016-01-01

    The aim of this study is to report a case of gold shunt surgery for uncontrolled, low-tension glaucoma with good central vision, after having a previously failed trabeculectomy and tube shunt surgeries. The patient was receiving maximum medical glaucoma therapy of four different types with intraocular pressure of 17 mm Hg prior to gold shunt surgery. Five years later, intraocular pressure is well controlled in the low teens without the need for ocular medications, and glaucoma is stable following gold shunt surgery. PMID:27051320

  10. Hydrocele of the canal of Nuck as a result of a rare ventriculoperitoneal shunt complication.

    PubMed

    Yuksel, K Z; Senoglu, M; Yuksel, M; Ozkan, K U

    2006-01-01

    Patients with ventriculoperitoneal (VP) shunts may have multiple complications. Migration of the peritoneal catheter into some anatomical or congenitally open cavities can cause inguinal or genitourinary manifestations such as hernia, hydrocele or acute scrotum, and these are common in male infants. We report a very rare complication of VP shunt encountered in a female infant, manifesting as hydrocele of the canal of Nuck, the female counterpart of hydrocele of the spermatic cord. It is emphasized that VP shunts may also cause clinical inguinal manifestations in female infants, and groin or external genital organ swelling in these patients may be an important sign of shunt malfunction.

  11. Evidence for a patent fibrous tract in fractured, outgrown, or disconnected ventriculoperitoneal shunts.

    PubMed

    Clyde, B L; Albright, A L

    1995-01-01

    As cerebrospinal fluid (CSF) shunts function for several years, outgrowth and disconnection of the distal catheter are seen more frequently. Though a shunt revision is clearly indicated if patients are symptomatic, asymptomatic patients with a disconnection or who have outgrown the distal catheter may no longer require CSF diversion. This follows an assumption that the shunt is no longer functioning and, in an asymptomatic patient, no longer required. However, patent fibrous tracts have been postulated which may allow passage of CSF through disconnected or outgrown distal catheters. We have recently treated 2 patients with ventriculoperitoneal (VP) shunts with evidence of a persistent fibrous tract. A 13-year-old boy was asymptomatic for 2 years after radiographs revealed an outgrown distal VP shunt catheter, after which the acutely deteriorated and died from massive hydrocephalus, although the entire shunt was patent. Another 14-year-old boy who was profoundly retarded presented with subtle changes in his daily activity. Shunt radiographs revealed two disconnections and a broken valve, but a shunt tap revealed a normal opening pressure (OP). A radionuclide shuntogram revealed rapid passage of isotope through fibrous sheaths at the disconnections, and into the peritoneum. A shunt revision was performed and the patient returned to his previous level of health. Patients with outgrown or disconnected distal catheters may be asymptomatic and/or have normal OP, and must not be assumed to have arrested hydrocephalus. A ventricular pressure measurement and radionuclide shuntogram should be performed to rule out a patent persistent fibrous tract.

  12. Persistent portosystemic shunts after deceased donor liver transplant causing episodic hepatic encephalopathy despite good graft function

    PubMed Central

    Barritt, A. Sidney; Fried, Michael W.; Hayashi, Paul H.

    2011-01-01

    We describe two cases of post liver transplant encephalopathy caused by persistent portosystemic shunts despite good graft function. Such recurrence of encephalopathy due to persistent shunting has not been reported in the deceased donor liver transplant literature. Our patients had episodic hepatic encephalopathy concordant with elevated serum ammonia levels due to well documented persistent portosystemic shunts. In one of our cases, the shunt was obliterated via coil embolization. This patient's encephalopathy resolved completely and has not recurred over seven months of follow up. The second patient has declined an intervention, but has remained symptom free on maintenance lactulose and rifaximin. PMID:19655248

  13. PORTACAVAL SHUNT IN PATIENTS WITH CIRRHOSIS—After-Effects of the Operation

    PubMed Central

    Benson, John A.

    1961-01-01

    The subject of the indications for operation for portacaval shunt bristles with problems to which a satisfactory answer cannot yet be given. I have discussed those events which supervene after a portacaval shunt which, in the present state of knowledge, has been directed as proper and well-intentioned therapy. It is against the knowledge of such post-shunt events and the complexity of their management, as well as the success of the operation and the risk of mortality, that one must balance the indications for surgery. This is particularly pertinent to the application of prophylactic shunt surgery now under consideration. PMID:18732366

  14. Robert H. Pudenz (1911-1998) and Ventriculoatrial Shunt: Historical Perspective.

    PubMed

    Konar, Subhas K; Maiti, Tanmoy K; Bir, Shyamal C; Kalakoti, Piyush; Nanda, Anil

    2015-11-01

    Robert H. Pudenz was a renowned neurosurgeon in North America in the 20th century, famous for his contributions in the evolution of the shunt valve and ventriculoatrial shunt surgery. With his innovative idea and help from Heyer, in 1955, he demonstrated that a venous catheter worked best when in the right atrium and that the slit valve should be located at the most distal portion of the shunt system to prevent retrograde filling and thrombosis. He also contributed to various experimental studies on the brain, especially the electrical response of different neural structures. This historical vignette focuses on the work of Robert Pudenz and the evolution of the ventriculoatrial shunt.

  15. Spontaneous knot formation in the peritoneal catheter: a rare cause of ventriculoperitoneal shunt malfunction.

    PubMed

    Charalambides, Constantinos; Sgouros, Spyros

    2012-01-01

    Ventriculoperitoneal shunt malfunction is a relatively common problem encountered in shunted hydrocephalic patients and is attributed most frequently to mechanical obstruction of the ventricular catheter. We present the case of a rare cause of mechanical obstruction of the peritoneal catheter due to the spontaneous formation of a knot just underneath the abdominal wound. This occurred 1 year after shunt implantation and is thought to have been caused by a combination of plastic material memory and bowel peristaltic movements. This case brings for discussion the role of radiographic investigation of the shunt system in children who present with suspected shunt obstruction. Radiographic investigation is warranted in children who have unusual shunt arrangements (e.g., Y-connectors and multiple catheters) in order to exclude disconnections or those who develop shunt problems years after implantation, to exclude material fracture in the neck or migration of any kind. In shunt systems which have been implanted for shorter time periods, the need for radiographs is less apparent. Some surgeons proclaim that when clinical circumstances fall outside the realms of obvious possible proximal obstruction, radiographic evaluation of the shunt system should be considered. PMID:23816925

  16. The role of persistent foramen ovale and other shunts in decompression illness.

    PubMed

    Wilmshurst, Peter T

    2015-06-01

    A persistent foramen ovale (PFO) and other types of right-to-left shunts are associated with neurological, cutaneous and cardiovascular decompression illness (DCI). A right-to-left shunt is particularly likely to be implicated in causation when these types of DCI occur after dives that are not provocative. It is believed that venous nitrogen bubbles that form after decompression pass through the shunt to circumvent the lung filter and invade systemic tissues supersaturated with nitrogen (or other inert gas) and as a result there is peripheral amplification of bubble emboli in those tissues. Approximately a quarter of the population have a PFO, but only a small proportion of the population with the largest right-to-left shunts are at high risk of shunt-mediated DCI. The increased risk of DCI in people with migraine with aura is because migraine with aura is also associated with right-to-left shunts and this increased risk of DCI appears to be confi ned to those with a large PFO or other large shunt. Various ultrasound techniques can be used to detect and assess the size of right-to-left shunts by imaging the appearance of bubble contrast in the systemic circulation after intravenous injection. In divers with a history of shunt-mediated DCI, methods to reduce the risk of recurrence include cessation of diving, modification of future dives to prevent venous bubble liberation and transcatheter closure of a PFO.

  17. The role of persistent foramen ovale and other shunts in decompression illness.

    PubMed

    Wilmshurst, Peter T

    2015-06-01

    A persistent foramen ovale (PFO) and other types of right-to-left shunts are associated with neurological, cutaneous and cardiovascular decompression illness (DCI). A right-to-left shunt is particularly likely to be implicated in causation when these types of DCI occur after dives that are not provocative. It is believed that venous nitrogen bubbles that form after decompression pass through the shunt to circumvent the lung filter and invade systemic tissues supersaturated with nitrogen (or other inert gas) and as a result there is peripheral amplification of bubble emboli in those tissues. Approximately a quarter of the population have a PFO, but only a small proportion of the population with the largest right-to-left shunts are at high risk of shunt-mediated DCI. The increased risk of DCI in people with migraine with aura is because migraine with aura is also associated with right-to-left shunts and this increased risk of DCI appears to be confi ned to those with a large PFO or other large shunt. Various ultrasound techniques can be used to detect and assess the size of right-to-left shunts by imaging the appearance of bubble contrast in the systemic circulation after intravenous injection. In divers with a history of shunt-mediated DCI, methods to reduce the risk of recurrence include cessation of diving, modification of future dives to prevent venous bubble liberation and transcatheter closure of a PFO. PMID:26165532

  18. Optimization of shunt placement for the Norwood surgery using multi-domain modeling.

    PubMed

    Moghadam, Mahdi Esmaily; Migliavacca, Francesco; Vignon-Clementel, Irene E; Hsia, Tain-Yen; Marsden, Alison L

    2012-05-01

    An idealized systemic-to-pulmonary shunt anatomy is parameterized and coupled to a closed loop, lumped parameter network (LPN) in a multidomain model of the Norwood surgical anatomy. The LPN approach is essential for obtaining information on global changes in cardiac output and oxygen delivery resulting from changes in local geometry and physiology. The LPN is fully coupled to a custom 3D finite element solver using a semi-implicit approach to model the heart and downstream circulation. This closed loop multidomain model is then integrated with a fully automated derivative-free optimization algorithm to obtain optimal shunt geometries with variable parameters of shunt diameter, anastomosis location, and angles. Three objective functions: (1) systemic; (2) coronary; and (3) combined systemic and coronary oxygen deliveries are maximized. Results show that a smaller shunt diameter with a distal shunt-brachiocephalic anastomosis is optimal for systemic oxygen delivery, whereas a more proximal anastomosis is optimal for coronary oxygen delivery and a shunt between these two anatomies is optimal for both systemic and coronary oxygen deliveries. Results are used to quantify the origin of blood flow going through the shunt and its relationship with shunt geometry. Results show that coronary artery flow is directly related to shunt position. PMID:22757490

  19. Embolization of portal-systemic shunts in cirrhotic patients with chronic recurrent hepatic encephalopathy

    SciTech Connect

    Sakurabayashi, Shin; Sezai, Shuichi; Yamamoto, Yoshihiro; Hirano, Masanori; Oka, Hiroshi

    1997-03-15

    Purpose. To evaluate the efficacy of embolization of portal-systemic shunts in cirrhotic patients with chronic recurrent hepatic encephalopathy (CRHE). Methods. Seven cirrhotic patients with CRHE refractory to medical treatment (3 men and 4 women, mean age 66 years) were studied. Five patients had splenorenal shunts, 1 had a gastrorenal shunt, and 1 had an intrahepatic portal vein-hepatic vein shunt. Shunt embolization was performed using stainless steel coils, with a percutaneous transhepatic portal vein approach in 4 patients and a transrenal vein approach in 3 patients. Results. After embolization, the shunt disappeared in 4 patients on either ultrasound pulsed Doppler monitoring or portography. Complications observed in the 7 patients were fever, transient pleural effusion, ascites, and mild esophageal varices. For 3-6 months after embolization, the 4 patients whose shunts disappeared showed minimal or no reappearance of a shunt, and had no recurrence of encephalopathy. The serum ammonia levels decreased and electroencephalograms also improved. One of the 4 patients, who developed mild esophageal varices, required no treatment. Treatment was effective in 3 of the 4 patients (75%) who underwent embolization via a transhepatic portal vein. Conclusion. Transvascular embolization of shunts improved the outcome in 4 of 7 patients. The most effective embolization was achieved via the percutaneous transhepatic portal vein approach.

  20. Ventriculo-peritoneal shunt malfunction due to complete migration and subgaleal coiling of the proximal and distal catheters.

    PubMed

    Pikis, Stylianos; Cohen, José E; Shoshan, Yigal; Benifla, Mony

    2015-01-01

    Ventriculo-peritoneal (VP) shunt malfunction due to proximal and distal catheter migration has been rarely reported in the literature. Shunt migration has been proposed to occur as a result of a combination of various mechanisms, including the windlass effect, retained memory of the shunt tubing, inadequate shunt fixation, and increased intra-abdominal pressures. We describe a rare case of a 6-week-old child who presented in our department with VP shunt malfunction due to complete proximal migration and coiling of the peritoneal and ventricular VP shunt catheters within a subgaleal pocket at the left occipital area.

  1. Interatrial shunt flow profiles in newborn infants: a colour flow and pulsed Doppler echocardiographic study.

    PubMed Central

    Hiraishi, S; Agata, Y; Saito, K; Oguchi, K; Misawa, H; Fujino, N; Horiguchi, Y; Yashiro, K

    1991-01-01

    Interatrial shunt flow profiles in 36 normal term infants were examined serially by colour flow and pulsed Doppler echocardiographic techniques from within an hour of birth to four or five days after birth. Shunt flow across the foramen ovale was detected in 33 normal infants (92%) within an hour of birth (mean 40 minutes). The occurrence of interatrial shunting decreased with age, but a shunt signal was still detected in 17 infants (47%) on the fourth or fifth day of life, by then the ductus arteriosus had already closed in all the normal infants. The direction of interatrial shunt flow was predominantly left-to-right, but in 64% there was a coexistent small right-to-left shunt in diastole within an hour of birth; by four to five days it was found in 19%. In the six patients with persistent fetal circulation the direction of the interatrial shunt flow was predominantly right-to-left with biphasic peaks in diastole and systole at the early stage of the disease, and the period of right-to-left shunt flow during each cardiac cycle was significantly longer than that in normal infants examined within 1 hour of birth. In all patients the ductus closed before the foramen ovale. At the time of ductal closure in all patients with persistent fetal circulation right-to-left shunt flow was seen during diastole and its period was still prolonged. These findings suggest that interatrial shunting, predominantly left-to-right, is common in normal newborn infants. Evaluation of the characteristics of the interatrial shunt by Doppler echocardiography may be useful for predicting the progress of or improvement in neonates with persistent fetal circulation. Images PMID:1993129

  2. Shunting arc plasma source for pure carbon ion beam.

    PubMed

    Koguchi, H; Sakakita, H; Kiyama, S; Shimada, T; Sato, Y; Hirano, Y

    2012-02-01

    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA∕mm(2) at the peak of the pulse.

  3. Shunting arc plasma source for pure carbon ion beama)

    NASA Astrophysics Data System (ADS)

    Koguchi, H.; Sakakita, H.; Kiyama, S.; Shimada, T.; Sato, Y.; Hirano, Y.

    2012-02-01

    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA/mm2 at the peak of the pulse.

  4. Laparoscopic removal of dislocated ventriculoperitoneal shunts. Report of two cases.

    PubMed

    Schrenk, P; Woisetschläger, R; Wayand, W U; Polanski, P

    1994-09-01

    In two patients the dislocated abdominal catheter of a ventriculoperitoneal (VP) shunt was successfully removed from the abdominal cavity by laparoscopy. Avoiding laparotomy, only two small abdominal incisions were necessary to insert the laparoscope and the grasping forceps. Postoperative course was uncomplicated except for protrusion of a part of the greater omentum through the umbilical incision in one patient. Both patients were mobilized on the operative day. Surgery required only 10 min, provided an excellent view of the entire abdomen, and led to prompt identification and removal of the lost catheter.

  5. Piezoelectric vibration damping using resonant shunt circuits: an exact solution

    NASA Astrophysics Data System (ADS)

    Soltani, P.; Kerschen, G.; Tondreau, G.; Deraemaeker, A.

    2014-12-01

    The objective of this paper is to propose an exact closed-form solution to the {{H}∞ } optimization of piezoelectric materials shunted with inductive-resistive passive electrical circuits. Realizing that Den Hartog's method which imposes fixed points of equal height in the receptance transfer function is approximate, the parameters of the piezoelectric tuned vibration absorber are calculated through the direct minimization of the maxima of the receptance. The method is applied to a one-degree-of-freedom primary oscillator considering various values of the electromechanical coupling coefficients.

  6. A theoretical and experimental study of coplanar waveguide shunt stubs

    NASA Technical Reports Server (NTRS)

    Dib, Nihad I.; Ponchak, George E.; Katehi, Linda P. B.

    1993-01-01

    A comprehensive theoretical and experimental study of straight and bent coplanar waveguide (CPW) shunt stubs is presented. In the theoretical analysis, the CPW is assumed to be inside a cavity while, the experiments are performed on open structures. For the analysis of CPW discontinuities with air-bridges, a hybrid technique was developed which was validated through extensive theoretical and experimental comparisons. The effect of the cavity resonances on the behavior of the stubs with and without air-bridges is investigated. In addition, the encountered radiation loss due to the discontinuities is evaluated experimentally.

  7. 69 kV shunt capacitor bank specification considerations

    SciTech Connect

    Fenner, G.E. )

    1992-01-01

    PSI has standardized on the 69 kv ungrounded star, 7.2 mvar or multiple of the 7.2 mvar shunt capacitor bank for var control. This document defines the considerations to be addressed when specifying a 69 kv ungrounded capacitor bank and for providing suitable protection. The design goal is to provide a bank that is reliable and meets operational requirements at minimum cost with standard components. The bank components will be discussed separately. This paper defines the considerations for specifying capacitor banks to minimize cost, improve reliability and help standardize design. The components making up the bank will be individually discussed with special emphasis on the protection and control.

  8. RHIC INSERTION REGION, SHUNT POWER SUPPLY CURRENT ERRORS.

    SciTech Connect

    BRUNO,D.; GANETIS,G.; LAMBIASE,R.F.; SANDBERG,J.

    2001-06-18

    The Relativistic Heavy Ion Collider (RHIC) was commissioned in 1999 and 2000. RHIC requires power supplies to supply currents to highly inductive superconducting magnets. The RHIC Insertion Region contain's many shunt power supplies to trim the current of different magnet elements in a large superconducting magnet circuit. Power Supply current error measurements were performed during the commissioning of RHIC. Models of these power supply systems were produced to predict and improve these power supply current errors using the circuit analysis program MicroCap V by Spectrum Software (TM). Results of the power supply current errors are presented from the models and from the measurements performed during the commissioning of RHIC.

  9. Time to First Shunt Failure in Pediatric Patients over 1 Year Old: A 10-Year Retrospective Study.

    PubMed

    Shannon, Chevis N; Carr, Kevin R; Tomycz, Luke; Wellons, John C; Tulipan, Noel

    2013-01-01

    Studies comparing alternatives to ventriculoperitoneal (VP) shunting for treatment of hydrocephalus have often relied upon data from an earlier era that may not be representative of contemporary shunt survival outcomes. We sought to determine the shunt survival rate of our cohort and compare our results to previously published shunt survival and endoscopic third ventriculostomy (ETV) success rates. We identified 95 patients between 1 and 18 years of age, who underwent initial VP shunt placement between January 2001 and December 2010. Our study shows a shunt survival rate of 85% at 6 months and 79% at 2 years, for initial shunts in pediatric patients over 1 year of age in this cohort. The overall infection rate was 3%. This compares favorably with published success rates of ETV at similar time points as well as with the rate of infection. This suggests that ventricular shunting remains a viable alternative to ETV in the older child.

  10. Transcatheter closure of modified Blalock-Taussig shunt with Gianturco-Grifka Vascular Occlusion Device.

    PubMed

    Hoyer, M H; Leon, R A; Fricker, F J

    1999-12-01

    A 15-year-old girl with previous repair of a complex cyanotic congenital heart defect had persistence of a modified left Blalock-Taussig shunt that could not be ligated at surgery. Six years later, antegrade delivery of a Gianturco-Grifka Vascular Occlusion Device resulted in complete closure of the shunt. Cathet. Cardiovasc. Intervent. 48:365-367, 1999. PMID:10559814

  11. Shunt Devices for the Treatment of Adult Hydrocephalus: Recent Progress and Characteristics

    PubMed Central

    MIYAKE, Hiroji

    2016-01-01

    Various types of shunt valves have been developed during the past 50 years, most of which can be classified into the following categories: (1) fixed differential pressure valves; (2) fixed differential pressure (DP) valves with an antisiphon mechanism; (3) programmable DP valves; (4) programmable DP valves with an antisiphon mechanism; and (5) programmable antisiphon valves. When considering the myriad of possible postoperative condition changes, such as the onset of accidental non-related diseases or trauma in adults, and changes in normal physiological development or anticipation of future shunt removal in children, it has become standard to use the programmable valve as a first choice for cerebrospinal fluid shunting. However, it is still unclear what type of shunt valve is suitable for each individual case. Based on the results of SINPHONI and more recently SINPHONI 2 trials, the programmable DP valve is recommended as the first line shunt valve. The programmable DP valve with an antisiphon mechanism is thought to be beneficial for tall, slender patients, who have a tendency for easily developing complications of overdrainage, however, this type of valve must be used cautiously in obese patients because of the increased risk of underdrainage. Although the current evidence is still insufficient, the programmable antisiphon valve, which costs the same as the programmable DP valve, is also thought to be the first line shunt valve. The quick reference table is applicable for most shunt valves, and for patients with either the ventriculoperitoneal or the lumboperitoneal shunt. PMID:27041631

  12. Immune reactions associated with silicone-based ventriculo-peritoneal shunt malfunctions in children.

    PubMed

    VandeVord, Pamela J; Gupta, Nalini; Wilson, Russell B; Vinuya, Ricardo Z; Schaefer, Caralee J; Canady, Alexa I; Wooley, Paul H

    2004-08-01

    The implantation of ventriculo-peritoneal (VP) shunting systems is the most commonly performed neurological procedure in children with hydrocephalus. Although the overall complication risk is low, the cumulative risk of shunt failure is high and unfortunately results in a high prevalence of revision surgeries. In this study, we explored the concept that some pediatric patients may develop an immune response to either the proteins attached to the silicone implant surface or to the biomaterial itself, and that this reaction may contribute to VP shunt failure in some individuals. The data displays that the sterile shunt malfunction group had a higher rate of protein deposition and increased levels of autoantibodies to the extracted surface proteins as compared to individuals with functioning shunting systems. The precise nature of the shunt-bound proteins that serve as antigens in this experiment have not yet been determined. The data also indicated that some individuals develop antibodies to polymeric substances that cross-react with partially polymerized acrylamide. The detection of significant amounts of shunt-bound protein, antibody responses to these proteins and to polymeric substances suggest that an immunological response to these proteins may play a role in the mechanism behind sterile shunt malfunctions.

  13. Two episodes of ventriculoperitoneal shunt migration in a patient with idiopathic intracranial hypertension.

    PubMed

    Balakrishnan, V; Jeanmonod, R

    2014-01-01

    Introduction. Ventriculoperitoneal shunts are often placed as treatment for refractory idiopathic intracranial hypertension. Dislodgement and migration of the distal portion of the shunt are more common in obese patients and can be difficult to detect. We report the case of a woman with two separate episodes of shunt migration into her abdominal wall. Case Presentation. We report a case of a 37-year-old female with history of obesity eventually diagnosed with idiopathic intracranial hypertension (IIH) as the cause. She failed outpatient therapy and, through neurosurgery, had a VP shunt placed for symptom control. She had subsequent development of worsened symptoms that were found to be due to shunt migration. This happened not once but twice to the same patient. Conclusion. Shunt dislodgement, migration, and subsequent failure are common in obese patients who have shunts placed for IIH. The medical provider should maintain a high index of suspicion for shunt malfunction in these patients, particularly because clinical evaluation may be challenging due to habitus.

  14. [Migration of a ventriculoperitoneal shunt in the liver: A rare complication].

    PubMed

    Eap, C; Blauwblomme, T; Dupuy, L; Bennis, S; Faber, B; Mireau, E; Aldea, S; Frileux, P; Gaillard, S

    2012-12-01

    We report on a case of migration inside the liver of the distal end of a ventriculoperitoneal shunt catheter in an adult patient. A simple laparotomy permitted the surgical removal with no haemorrhagic complication. We discuss the other cases reported in the literature and we outline the need to perform an abdominal CT scan in patients carrying a VP shunt with digestive symptoms.

  15. Visual disturbance following shunt malfunction in a patient with congenital hydrocephalus.

    PubMed

    Oyama, Hirofumi; Hattori, Kenichi; Kito, Akira; Maki, Hideki; Noda, Tomoyuki; Wada, Kentaro

    2012-01-01

    A 25-year-old woman presented with complaints of nausea and headache. She had been treated with a ventriculoperitoneal shunt for hydrocephalus when she was 7 months old. Her bilateral optic discs showed moderate atrophy. Right visual acuity allowed only perception of hand movement and left visual acuity was 0.02 (1.2). Computed tomography (CT) showed mild ventricular dilation but no periventricular lucency. Intracranial pressure (ICP) was not high when the shunt valve was punctured. Her visual acuity deteriorated 5 days after the consultation. She was referred again 8 days after the first consultation. The bilateral optic discs were completely pale. Both pupils were dilated on admission, and the bilateral direct light reflexes were absent. The patient could slightly detect only green light stimulus. CT showed moderate enlargement of the ventricle. ICP was 47 cmH(2)O when the shunt valve was punctured. Shuntgraphy showed obstruction of the shunt at the distal end of peritoneal catheter. Emergent total shunt revision was performed. She could detect dark stimulus and the still-dilated left pupil had recovered direct light reflex on the next day. The visual acuity was 0.01 (0.7) on the left 6 months after the operation, although she was blind in the right eye and the bilateral optic discs were completely pale. Visual loss associated with shunt failure remains a major morbidity in shunted congenital hydrocephalus. Early diagnosis and shunt revision may allow visual recovery.

  16. Shunt Devices for the Treatment of Adult Hydrocephalus: Recent Progress and Characteristics.

    PubMed

    Miyake, Hiroji

    2016-05-15

    Various types of shunt valves have been developed during the past 50 years, most of which can be classified into the following categories: (1) fixed differential pressure valves; (2) fixed differential pressure (DP) valves with an antisiphon mechanism; (3) programmable DP valves; (4) programmable DP valves with an antisiphon mechanism; and (5) programmable antisiphon valves. When considering the myriad of possible postoperative condition changes, such as the onset of accidental non-related diseases or trauma in adults, and changes in normal physiological development or anticipation of future shunt removal in children, it has become standard to use the programmable valve as a first choice for cerebrospinal fluid shunting. However, it is still unclear what type of shunt valve is suitable for each individual case. Based on the results of SINPHONI and more recently SINPHONI 2 trials, the programmable DP valve is recommended as the first line shunt valve. The programmable DP valve with an antisiphon mechanism is thought to be beneficial for tall, slender patients, who have a tendency for easily developing complications of overdrainage, however, this type of valve must be used cautiously in obese patients because of the increased risk of underdrainage. Although the current evidence is still insufficient, the programmable antisiphon valve, which costs the same as the programmable DP valve, is also thought to be the first line shunt valve. The quick reference table is applicable for most shunt valves, and for patients with either the ventriculoperitoneal or the lumboperitoneal shunt.

  17. Transient right-to-left shunting through a patent foramen ovale secondary to unilateral diaphragmatic paralysis.

    PubMed Central

    Cordero, P. J.; Morales, P.; Mora, V.; Cebrian, J.; Vallterra, J.; Gudin, J.; Benlloch, E.; Marco, V.

    1994-01-01

    A 57 year old patient presented with unilateral diaphragmatic paralysis and severe hypoxaemia secondary to transient right-to-left interatrial shunting through a patent foramen ovale. The final diagnosis was made because of the initial detection of a shunt while the patient was breathing 100% oxygen. Images PMID:7940438

  18. Ventriculoperitoneal shunt for treatment of hydrocephalus in a French bulldog puppy

    PubMed Central

    Giacinti, Jolene A.

    2016-01-01

    A 6.5-week-old bulldog was presented with lethargy, anorexia, and stunted growth. A domed skull, ventrolateral strabismus, hypermetria, and delayed hopping were observed. Congenital hydrocephalus was diagnosed and a ventriculoperitoneal shunt was placed. After surgery, a shunt obstruction occurred but resolved with treatment. The puppy responded well and neurological deficits continued to improve after surgery. PMID:26933271

  19. Normal-pressure hydrocephalus: current understanding of diagnostic tests and shunting

    SciTech Connect

    Black, P.M.

    1982-02-01

    Normal-pressure hydrocephalus is no longer difficult to diagnose or treat-cranial computed tomographic scanning has made the diagnosis of ventricular enlargement straightforward, and shunt placement often helps the patient whose condition can be traced to a specific cause. Predicting accurately whether a patient will benefit from a shunt, however, is still problematic.

  20. 21 CFR 882.5550 - Central nervous system fluid shunt and components.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Central nervous system fluid shunt and components. 882.5550 Section 882.5550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... shunt is a device or combination of devices used to divert fluid from the brain or other part of...

  1. 21 CFR 882.5550 - Central nervous system fluid shunt and components.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Central nervous system fluid shunt and components. 882.5550 Section 882.5550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... shunt is a device or combination of devices used to divert fluid from the brain or other part of...

  2. 21 CFR 882.5550 - Central nervous system fluid shunt and components.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Central nervous system fluid shunt and components. 882.5550 Section 882.5550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... shunt is a device or combination of devices used to divert fluid from the brain or other part of...

  3. Electroacoustic absorbers: bridging the gap between shunt loudspeakers and active sound absorption.

    PubMed

    Lissek, Hervé; Boulandet, Romain; Fleury, Romain

    2011-05-01

    The acoustic impedance at the diaphragm of an electroacoustic transducer can be varied using a range of basic electrical control strategies, amongst which are electrical shunt circuits. These passive shunt techniques are compared to active acoustic feedback techniques for controlling the acoustic impedance of an electroacoustic transducer. The formulation of feedback-based acoustic impedance control reveals formal analogies with shunt strategies, and highlights an original method for synthesizing electric networks ("shunts") with positive or negative components, bridging the gap between passive and active acoustic impedance control. This paper describes the theory unifying all these passive and active acoustic impedance control strategies, introducing the concept of electroacoustic absorbers. The equivalence between shunts and active control is first formalized through the introduction of a one-degree-of-freedom acoustic resonator accounting for both electric shunts and acoustic feedbacks. Conversely, electric networks mimicking the performances of active feedback techniques are introduced, identifying shunts with active impedance control. Simulated acoustic performances are presented, with an emphasis on formal analogies between the different control techniques. Examples of electric shunts are proposed for active sound absorption. Experimental assessments are then presented, and the paper concludes with a general discussion on the concept and potential improvements.

  4. Soluble membrane attack complex is diagnostic for intraventricular shunt infection in children

    PubMed Central

    Ramos, Theresa N.; Arynchyna, Anastasia A.; Blackburn, Tessa E.; Johnston, James M.

    2016-01-01

    BACKGROUND. Children treated with cerebrospinal fluid (CSF) shunts to manage hydrocephalus frequently develop shunt failure and/or infections, conditions that present with overlapping symptoms. The potential life-threatening nature of shunt infections requires rapid diagnosis; however, traditional microbiology is time consuming, expensive, and potentially unreliable. We set out to identify a biomarker that would identify shunt infection. METHODS. CSF was assayed for the soluble membrane attack complex (sMAC) by ELISA in patients with suspected shunt failure or infection. CSF was obtained at the time of initial surgical intervention. Statistical analysis was performed to assess the diagnostic potential of sMAC in pyogenic-infected versus noninfected patients. RESULTS. Children with pyogenic shunt infection had significantly increased sMAC levels compared with noninfected patients (3,211 ± 1,111 ng/ml vs. 26 ± 3.8 ng/ml, P = 0.0001). In infected patients undergoing serial CSF draws, sMAC levels were prognostic for both positive and negative clinical outcomes. Children with delayed, broth-only growth of commensal organisms (P. acnes, S. epidermidis, etc.) had the lowest sMAC levels (7.96 ± 1.7 ng/ml), suggesting contamination rather than shunt infection. CONCLUSION. Elevated CSF sMAC levels are both sensitive and specific for diagnosing pyogenic shunt infection and may serve as a useful prognostic biomarker during recovery from infection. FUNDING. This work was supported in part by the Impact Fund of Children’s of Alabama.

  5. Shunt Devices for the Treatment of Adult Hydrocephalus: Recent Progress and Characteristics.

    PubMed

    Miyake, Hiroji

    2016-05-15

    Various types of shunt valves have been developed during the past 50 years, most of which can be classified into the following categories: (1) fixed differential pressure valves; (2) fixed differential pressure (DP) valves with an antisiphon mechanism; (3) programmable DP valves; (4) programmable DP valves with an antisiphon mechanism; and (5) programmable antisiphon valves. When considering the myriad of possible postoperative condition changes, such as the onset of accidental non-related diseases or trauma in adults, and changes in normal physiological development or anticipation of future shunt removal in children, it has become standard to use the programmable valve as a first choice for cerebrospinal fluid shunting. However, it is still unclear what type of shunt valve is suitable for each individual case. Based on the results of SINPHONI and more recently SINPHONI 2 trials, the programmable DP valve is recommended as the first line shunt valve. The programmable DP valve with an antisiphon mechanism is thought to be beneficial for tall, slender patients, who have a tendency for easily developing complications of overdrainage, however, this type of valve must be used cautiously in obese patients because of the increased risk of underdrainage. Although the current evidence is still insufficient, the programmable antisiphon valve, which costs the same as the programmable DP valve, is also thought to be the first line shunt valve. The quick reference table is applicable for most shunt valves, and for patients with either the ventriculoperitoneal or the lumboperitoneal shunt. PMID:27041631

  6. Shunt currents in vanadium flow batteries: Measurement, modelling and implications for efficiency

    NASA Astrophysics Data System (ADS)

    Fink, H.; Remy, M.

    2015-06-01

    Shunt currents are an important factor which must be considered when designing a stack for flow batteries. They lead to a reduction of the coulombic efficiency and can cause furthermore a critical warming of the electrolyte. Shunt currents inevitably appear at bypass connections of the hydraulic system between the single cells of a stack. In this work the shunt currents of a five-celled mini stack of a vanadium flow battery with external hydraulic system and their effects are investigated directly. The external hydraulic system allows the implementation of current sensors for direct measurement of the shunt currents; moreover, the single bypass channels can be interrupted by clamping the tube couplings and with it the shunt currents between the cells when the pumps are off. Thus the shares of losses by cross contamination and by shunt currents are quantified separately by charge conservation measurements. The experimentally gained data are compared to a shunt current model based on a equivalent circuit diagram and the linear equation system derived from it. Experiments and model data are in good agreement. The effects of shunt currents for different flow frame geometries and number of cells in a stack are simulated and presented in this work.

  7. Electroacoustic absorbers: bridging the gap between shunt loudspeakers and active sound absorption.

    PubMed

    Lissek, Hervé; Boulandet, Romain; Fleury, Romain

    2011-05-01

    The acoustic impedance at the diaphragm of an electroacoustic transducer can be varied using a range of basic electrical control strategies, amongst which are electrical shunt circuits. These passive shunt techniques are compared to active acoustic feedback techniques for controlling the acoustic impedance of an electroacoustic transducer. The formulation of feedback-based acoustic impedance control reveals formal analogies with shunt strategies, and highlights an original method for synthesizing electric networks ("shunts") with positive or negative components, bridging the gap between passive and active acoustic impedance control. This paper describes the theory unifying all these passive and active acoustic impedance control strategies, introducing the concept of electroacoustic absorbers. The equivalence between shunts and active control is first formalized through the introduction of a one-degree-of-freedom acoustic resonator accounting for both electric shunts and acoustic feedbacks. Conversely, electric networks mimicking the performances of active feedback techniques are introduced, identifying shunts with active impedance control. Simulated acoustic performances are presented, with an emphasis on formal analogies between the different control techniques. Examples of electric shunts are proposed for active sound absorption. Experimental assessments are then presented, and the paper concludes with a general discussion on the concept and potential improvements. PMID:21568400

  8. Characteristic lesion pattern and echocardiographic findings in extra-cardiac shunt-related stroke.

    PubMed

    Mun, Jun Kyu; Park, Sung Ji; Kim, Suk Jae; Bang, Oh Young; Chung, Chin-Sang; Lee, Kwang Ho; Kim, Gyeong-Moon

    2016-10-15

    Among embolic strokes of undetermined source, under-recognized etiology such as extra-cardiac shunt could be a potential risk factor. We sought to characterize infarction patterns on diffusion-weighted imaging (DWI) and transesophageal echocardiography (TEE) findings in extra-cardiac shunt-related stroke. We enrolled 96 consecutive patients with cryptogenic stroke who had an extra- or intra-cardiac shunt. Diagnosis of the shunt was performed using TEE with agitated saline contrast and pulmonary vein isolation. Infarction patterns on DWI and total lesion volume were analyzed. Bubble amounts through the shunt were classified via the International Consensus Criteria (ICC). Short-term prognosis, patterns and size of DWI lesions, and involved vascular territories were not significantly different between two groups. Multivariate analysis revealed that extra-cardiac shunt group has a smaller total infarct volume (odds ratio [OR]=0.427, 95% confidence interval [95% CI] 0.228-0.799, p=0.008), and significantly higher bubble grade during resting state and lower grade during the Valsalva maneuver (OR= 0.539, 95% CI 0.438-0.663, p<0.001). Stroke related to an extra-cardiac shunt presented smaller infarct volume, favorable clinical outcomes and characteristic finding on TEE with agitated saline contrast. Further study is needed to confirm whether the extra-cardiac shunt is an independent risk factor. PMID:27653885

  9. 21 CFR 882.5550 - Central nervous system fluid shunt and components.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Central nervous system fluid shunt and components. 882.5550 Section 882.5550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... shunt is a device or combination of devices used to divert fluid from the brain or other part of...

  10. 21 CFR 882.5550 - Central nervous system fluid shunt and components.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Central nervous system fluid shunt and components. 882.5550 Section 882.5550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... shunt is a device or combination of devices used to divert fluid from the brain or other part of...

  11. Sound absorption of a finite micro-perforated panel backed by a shunted loudspeaker.

    PubMed

    Tao, Jiancheng; Jing, Ruixiang; Qiu, Xiaojun

    2014-01-01

    Deep back cavities are usually required for micro-perforated panel (MPP) constructions to achieve good low frequency absorption. To overcome the problem, a close-box loudspeaker with a shunted circuit is proposed to substitute the back wall of the cavity of the MPP constructions to constitute a composite absorber. Based on the equivalent circuit model, the acoustic impedance of the shunted loudspeaker is formulated first, then a prediction model of the sound absorption of the MPP backed by shunted loudspeaker is developed by employing the mode solution of a finite size MPP coupled by an air cavity with an impendence back wall. The MPP absorbs mid to high frequency sound, and with properly adjusted electrical parameters of its shunted circuit, the shunted loudspeaker absorbs low frequency sound, so the composite absorber provides a compact solution to broadband sound control. Numerical simulations and experiments are carried out to validate the model.

  12. An Unusual Complication of Ventriculoperitoneal Shunt: Urinary Bladder Stone Case Report and Literature Review

    PubMed Central

    Xu, Songtao; Sheng, Weixin; Qiu, Yufa; Wang, Jianguo

    2016-01-01

    Introduction: Ventriculoperitoneal (V-P) shunt surgery is the most common technique used for the treatment of hydrocephalus. The migration of ventriculoperitoneal shunt to the bladder is rare. Only two cases have been previously reported in the literature. Case Presentation: We report on a 38-year-old male who had hydrocephalus and V-P shunt for 12 years. Two years ago, he found himself with recurrent urinary tract infections, haematuria and urges incontinence, and then he was diagnosed with bladder perforation and merge stones. The patient had an abdominal operation to cut off and take out the shunt catheter, as well as a transurethral holmium laser lithotripsy. Conclusions: Bladder perforation and stones are rare examples of complications in V-P surgical procedures. Controlling the effective length of the terminal V-P shunt and modifying it appropriately can effectively reduce these complications. PMID:26889393

  13. Multiple Liver Abscesses Associated with Ventriculoperitoneal Shunt Infection: Case Report and Review of the Literature

    PubMed Central

    Yang, Tae Ki

    2013-01-01

    Liver abscess following ventriculoperitoneal (VP) shunting occurs very rarely. We report an unusual case of multiple liver abscesses caused by Staphylococcus capitis in a 50-year-old compromised woman due to a complicating VP shunt infection. We reviewed the nine cases of VP shunt complications reported in the English literature, and speculated that the most likely pathogenetic mechanism in our case is an infected peritoneal tip that migrated to and penetrated the liver, which subsequently caused the formation of multiple liver abscesses. The patient was successfully treated with percutaneous aspiration, drainage of the abscesses, intravenous antibiotics, and shunt revision. Awareness and vigilance of the possibility of liver abscess formation caused by VP shunt infection will help establish an early accurate diagnosis and therapeutic strategy. PMID:24379956

  14. Instantiating a mechatronic valve schedule for a hydrocephalus shunt.

    PubMed

    Momani, Lina; Alkharabsheh, Abdel Rahman; Al-Zuibi, Nayel; Al-Nuaimy, Waleed

    2009-01-01

    Hydrocephalus is caused by blockage or reabsorption difficulty that upsets the natural balance of production and absorption of cerebrospinal fluid in the brain, resulting in a build-up of the fluid in the ventricles of the brain. One of the recent advances in the treatment of hydrocephalus is the invention of a mechatronic valve. The desirability of such valve lies in the potential of having shunt that not only control hydrocephalus but also seeks to treat it. In contrast to current valves, such a valve is regulated based on a time based schedule not on the differential pressure across the valve. Thus the effectiveness of such valve is highly dependant on selecting an appropriate valve schedule that delivers personal dynamic treatment for every individual patient. Providing such a schedule is likely to be one of the obstacles facing the implementation of the mechatronic valve. In this paper, an algorithm is proposed to help in developing such a schedule that dynamically change based on the patients' own intracranial pressure data and a novel figure of merit, thus providing the physician with an easy tool that facilitate the use of the mechatronic valve. The algorithm was implemented in M ATLAB and Simulink. Real ICP data for three hydrocephalus patients (before shunting) were used to test this algorithm and the resulted schedules along with the resulted intracranial pressure data have illustrated the effectiveness of the algorithm in providing schedule that maintain ICP within the normal limits. PMID:19963474

  15. Fabrication and characterization of shunted μ-SQUID

    SciTech Connect

    Kumar, Nikhil; Fournier, T.; Courtois, H.; Gupta, Anjan K.

    2014-04-24

    In order to eliminate hysteresis, we have fabricated and characterized niobium based shunted micron size superconducting quantum interference devices (μ-SQUIDs). We find a wide temperature range where these μ-SQUIDs are non-hysteretic in nature and show a very good I{sub c} vs. B oscillations in hysteretic regime and V vs. B oscillations in non-hysteretic regime. Here we report the characteristics of a shunted- μ-SQUID (Wf38LS72D5). In this device we have achieved a large voltage modulation, in non-hysteretic regime, at various temperatures including such as 1.1 mV at 6.62 K with a transfer function V{sub Φ} = 7.2mV/Φ{sub 0}. The figures within the original article PDF file, as supplied to AIP Publishing, were affected by a PDF-processing error. Consequently, the article re-flowed and pagination increased from 3 to 4 pages. This article was updated on 14 May 2014 to correct the PDF-processing error, with the scientific content remaining unchanged. Readers are advised that the replacement article PDF file contains an additional blank page to preserve the original pagination.

  16. Fabrication and characterization of shunted μ-SQUID

    NASA Astrophysics Data System (ADS)

    Kumar, Nikhil; Fournier, T.; Courtois, H.; Gupta, Anjan K.

    2014-04-01

    In order to eliminate hysteresis, we have fabricated and characterized niobium based shunted micron size superconducting quantum interference devices (μ-SQUIDs). We find a wide temperature range where these μ-SQUIDs are non-hysteretic in nature and show a very good Ic vs. B oscillations in hysteretic regime and V vs. B oscillations in non-hysteretic regime. Here we report the characteristics of a shunted- μ-SQUID (Wf38LS72D5). In this device we have achieved a large voltage modulation, in non-hysteretic regime, at various temperatures including such as 1.1 mV at 6.62 K with a transfer function VΦ = 7.2mV/Φ0. The figures within the original article PDF file, as supplied to AIP Publishing, were affected by a PDF-processing error. Consequently, the article re-flowed and pagination increased from 3 to 4 pages. This article was updated on 14 May 2014 to correct the PDF-processing error, with the scientific content remaining unchanged. Readers are advised that the replacement article PDF file contains an additional blank page to preserve the original pagination.

  17. Transjugular Intrahepatic Portosystemic Shunt (TIPS): Current Status and Future Possibilities

    SciTech Connect

    Bilbao, Jose Ignacio; Quiroga, Jorge; Herrero, Jose Ignacio; Benito, Alberto

    2002-08-15

    Since the insertion of the first TIPS in 1989 much has been learned about this therapeutic procedure. It has an established role for the treatment of some complications of portal hypertension: prevention of recurrent variceal bleeding and rescue of patients with acute uncontrollable variceal bleeding. In addition TIPS is useful for Budd-Chiari syndrome, refractory ascites and hepatorenal syndrome, although its specific role in these indications remains to be definitively established. However, the decrease in sinusoidal blood flow induced by TIPS can lead to the patient developing hepatic encephalopathy and liver failure in some cases. Therefore, TIPS should be used with caution in patients with very poor liver function. From a technical point of view, successful placement of TIPS is achieved in more than 98% of cases by experienced groups. At present, evaluation of TIPS dysfunction based on morphology probably leads to an overdiagnosis of this complication since most of these cases are not associated with clinical manifestations (recurrent bleeding or refractory ascites). The major disadvantage of TIPS remains its poor long-term patency requiring a mandatory surveillance program. The indicator for shunt function/malfunction should be the portosystemic pressure gradient, which is best assessed by intravascular measurements. Shunt obstructions may be prevented or reduced by the use of stent-grafts in the future.

  18. Transjugular Intrahepatic Portosystemic Shunts in Children with Biliary Atresia

    SciTech Connect

    Huppert, Peter E.; Goffette, Pierre; Sokal, Emil M.; Schweizer, Paul; Claussen, Claus D.

    2002-12-15

    Purpose: We retrospectively evaluated the technical and long-term clinical results of transjugularintrahepatic portosystemic shunts (TIPS) in children with portal hypertension and biliary atresia (BA). Methods: Nine children with BA and recurrent bleeding from esophagogastric and/or intestinal varices were treated by TIPS at the age of 34-156 months and followed-up in two centers. Different types of stents were used. Results: Shunt insertion succeeded in all patients, but in two a second procedure was necessary. Seven procedures lasted more than 3 hr, mainly due to difficult portal vein puncture.Variceal bleeding ceased in all patients; however, 16 reinterventions were performed in eight patients for clinical reasons (n =11) and sonographically suspected restenosis (n =5). Four patients underwent successful liver transplantation 4-51 months after TIPS and five are in good clinical conditions 64-75 months after TIPS. Conclusions: TIPS in children with BA is technically difficult, mainly due to periportal fibrosis and small portal veins. Frequency of reinterventions seems to be higher compared with adults.

  19. Isolation and characterization of Salmonella typhimurium glyoxylate shunt mutants.

    PubMed Central

    Wilson, R B; Maloy, S R

    1987-01-01

    Growth of Salmonella typhimurium on acetate as a sole carbon source requires expression of the glyoxylate shunt; however, the genes for the glyoxylate shunt enzymes have not been previously identified in S. typhimurium. In this study, we isolated transposon insertions in the genes for the two unique enzymes of this pathway, aceA (isocitrate lyase) and aceB (malate synthase). The aceA and aceB genes were located at 89.5 min on the S. typhimurium genetic map. Genetic linkage to nearby loci indicated that the relative gene order is purDJ metA aceB aceA. Transposon insertions in aceB were polar on aceA, suggesting that the genes form an operon transcribed from aceB to aceA. Transcriptional regulation of the aceBA operon was studied by constructing mini-Mu d(lac Kan) operon fusions. Analysis of these fusions indicated that expression of the aceBA operon is regulated at the level of transcription; the aceBA genes were induced when acetate was present and repressing carbon sources were absent. Although glucose represses expression of the aceBA operon, repression does not seem to be mediated solely by cyclic AMP-cyclic AMP receptor protein complex. Mutants with altered regulation of the aceBA operon were isolated. PMID:3298210

  20. Nonvascular needle and shunt placements for fetal therapy.

    PubMed Central

    Holzgreve, W; Evans, M I

    1993-01-01

    The nonvascular placement of needles and shunts for the in utero treatment of fetuses with fluid-filled, space-occupying anomalies has been done for about 10 years. The rationale for this approach is to attempt to prevent progressive impairment of organ function or lethal damage by early decompression. Experience has taught us that the key to success in these cases is the exclusion of associated anomalies and the use of appropriate tests to assess the residual organ function at the time of first diagnosis. In fetuses with hydrothorax, shunts can prevent pulmonary hypoplasia, and in those with obstructive uropathy, they can prevent the development of progressive lung hypoplasia and renal damage before a fetus is fully viable. In fetuses with ovarian cysts, prenatal puncture is occasionally indicated, but in those with hydrocephalus, the beneficial effect of prenatal drainage is more controversial. The catheters used for in utero placement have been improved and carry a smaller risk than open fetal surgical procedures. Images PMID:8236975

  1. Laparoscopic Cholecystectomy for Acute Calcular Cholecystitis in a Patient with Ventriculoperitoneal Shunt: A Case Report and Literature Review

    PubMed Central

    Albarrak, Abdullah A.; Khairy, Sami; Ahmed, Alzahrani Mohammed

    2015-01-01

    Management of patients who have ventriculoperitoneal shunt presenting with acute calcular cholecystitis has remained a clinical challenge. In this paper, the hospital course and the follow-up of a patient presenting with acute calcular cholecystitis and ventriculoperitoneal shunt managed with laparoscopic cholecystectomy are presented followed by literature review on the management of acute calcular cholecystitis in patients who have ventriculoperitoneal shunts. PMID:26798543

  2. Hepatic Arterial Infusion Chemotherapy Combined with Venous Embolization in a Patient with Hepatic Metastases with an Arteriovenous Shunt

    SciTech Connect

    Nishiofuku, Hideyuki; Tanaka, Toshihiro; Sakaguchi, Hiroshi; Yamamoto, Kiyosei; Inoue, Masayoshi; Sueyoshi, Satoru; Shinnkai, Takayuki; Hasegawa, Masatoshi; Kichikawa, Kimihiko

    2009-07-15

    We describe herein a patient who had hepatic metastases with an arteriovenous shunt and was treated by hepatic arterial infusion chemotherapy. The arteriovenous shunt was diagnosed by {sup 99m}Tc-macroaggregated albumin scintigraphy and hepatic venous embolization was performed to reduce shunt flow.

  3. Relationship of the location of the ventricular catheter tip and function of the ventriculoperitoneal shunt.

    PubMed

    Yamada, Shoko Merrit; Kitagawa, Ryo; Teramoto, Akira

    2013-01-01

    The long-term maintenance of ventriculoperitoneal (VP) shunt function depends on the correct placement of the catheter tip in the lateral ventricle. The relationship between the location of the ventricular catheter tip and VP shunt function was analyzed in 52 patients. The location of the ventricular catheter tip was classified into one of the following five groups: (i) Group A--superior to the foramen of Monro; (ii) Group B--in the center of the lateral ventricle body; (iii) Group C--in the third ventricle; (iv) Group D--contacting the ventricle wall; and (v) Group E--in the septum pellucidum. VP shunt function was defined as well controlled hydrocephalus when the Evan's ratio of the ventricular size was < 0.3. The VP shunt functioned well in 14 of 52 patients (26.9%), the shunt valve pressure was incorrectly set in 21 (40.4%), and irreversible shunt malfunction was identified in 17 (32.7%). Among the 14 patients with a well-functioning shunt, 13 were in Groups A or B with an odds ratio (OR) of 17.875 (p<0.05). In the 17 irreversible shunt malfunctions, 13 were identified in Groups C, D, or E with an OR of 0.123 (p<0.05). Long term VP shunt function or failure due to irreversible malfunction is directly influenced by the position of the ventricular catheter tip. Ideal points for positioning the ventricular catheter tip are superior to the foramen of Monro and in the center of the lateral ventricle body. Early shunt revision may be required for patients in whom the catheter tip contacts the ventricle wall or is located in the septum pellucidum.

  4. Choice of valve type and poor ventricular catheter placement: Modifiable factors associated with ventriculoperitoneal shunt failure.

    PubMed

    Jeremiah, Kealeboga Josephine; Cherry, Catherine Louise; Wan, Kai Rui; Toy, Jennifer Ah; Wolfe, Rory; Danks, Robert Andrew

    2016-05-01

    Ventriculoperitoneal (VP) shunt insertion is a common neurosurgical procedure, essentially unchanged in recent years, with high revision rates. We aimed to identify potentially modifiable associations with shunt failure. One hundred and forty patients who underwent insertion of a VP shunt from 2005-2009 were followed for 5-9years. Age at shunt insertion ranged from 0 to 91years (median 44, 26% <18years). The main causes of hydrocephalus were congenital (26%), tumour-related (25%), post-haemorrhagic (24%) or normal pressure hydrocephalus (19%). Fifty-eight (42%) patients required ⩾1 shunt revision. Of these, 50 (88%) were for proximal catheter blockage. The median time to first revision was 108days. Early post-operative CT scans were available in 105 patients. Using a formal grading system, catheter placement was considered excellent in 49 (47%) but poor (extraventricular) in 13 (12%). On univariate analysis, younger age, poor ventricular catheter placement and use of a non-programmable valve were associated with shunt failure. On logistic regression modelling, the independent associations with VP shunt failure were poor catheter placement (odds ratio [OR] 4.9, 95% confidence interval [CI] 1.3-18.9, p=0.02) and use of a non-programmable valve (OR 0.4, 95% CI 0.2-1.0, p=0.04). In conclusion, poor catheter placement (revision rate 77%) was found to be the strongest predictor of shunt failure, with no difference in revisions between excellent (43%) and moderate (43%) catheter placement. Avoiding poor placement in those with mild or moderate ventriculomegaly may best reduce VP shunt failures. There may also be an influence of valve choice on VP shunt survival.

  5. Trans-anal protrusion of ventriculo-peritoneal shunt catheter with silent bowel perforation: report of ten cases in children.

    PubMed

    Ghritlaharey, Rajendra Kumar; Budhwani, K S; Shrivastava, Dhirendra K; Gupta, Gaurav; Kushwaha, Anand Singh; Chanchlani, Roshan; Nanda, Monika

    2007-06-01

    Ventriculo-peritoneal (VP) shunting used in the treatment for hydrocephalus is associated with several complications. Mechanical failure of shunt is the commonest complication of all. Visceral/bowel perforation is an unusual but serious complication of VP shunting. This article reports our experience in the management of ten children who had VP Shunt catheter protrusion from anus. This is a retrospective study of ten patients who had VP shunt catheter protrusion from anus, admitted in the department of paediatric surgery between Jan 1996 and Dec 2005. The records of above ten cases were reviewed for their clinical presentation and management, etc. We had performed 398 VP shunt operations in the last 10 years. Two hundred and seventy one (68.09%) VP Shunts were done for congenital hydrocephalus of which 164 were done in infancy/neonatal period and 107 VP shunts were done in the age group of >1-12 years. One hundred and twenty-seven (31.90%) VP shunt operations were done for patients who had hydrocephalus as a complication following tubercular meningitis (TBM). Out of 398 VP shunts, ten patients (2.51%) had protrusion of the distal end of peritoneal catheter from anus without causing/leading to peritonitis. We observed a 08.29% mortality of all VP shunt operations. Protrusion of VP shunt catheter per rectum can occur without producing peritonitis. Formal exploration and localization of entry of VP shunt catheter in bowel is not mandatory. Mini laparotomy and revision of peritoneal part of shunt can be done if there is no shunt infection.

  6. Universality of non-Ohmic shunt leakage in thin-film solar cells

    NASA Astrophysics Data System (ADS)

    Dongaonkar, S.; Servaites, J. D.; Ford, G. M.; Loser, S.; Moore, J.; Gelfand, R. M.; Mohseni, H.; Hillhouse, H. W.; Agrawal, R.; Ratner, M. A.; Marks, T. J.; Lundstrom, M. S.; Alam, M. A.

    2010-12-01

    We compare the dark current-voltage (IV) characteristics of three different thin-film solar cell types: hydrogenated amorphous silicon (a-Si:H) p-i-n cells, organic bulk heterojunction (BHJ) cells, and Cu(In,Ga)Se2 (CIGS) cells. All three device types exhibit a significant shunt leakage current at low forward bias (V <˜0.4) and reverse bias, which cannot be explained by the classical solar cell diode model. This parasitic shunt current exhibits non-Ohmic behavior, as opposed to the traditional constant shunt resistance model for photovoltaics. We show here that this shunt leakage (Ish), across all three solar cell types considered, is characterized by the following common phenomenological features: (a) voltage symmetry about V =0, (b) nonlinear (power law) voltage dependence, and (c) extremely weak temperature dependence. Based on this analysis, we provide a simple method of subtracting this shunt current component from the measured data and discuss its implications on dark IV parameter extraction. We propose a space charge limited (SCL) current model for capturing all these features of the shunt leakage in a consistent framework and discuss possible physical origin of the parasitic paths responsible for this shunt current mechanism.

  7. Portasystemic shunting versus liver transplantation for the Budd-Chiari syndrome.

    PubMed Central

    Bismuth, H; Sherlock, D J

    1991-01-01

    Over 12 years, 22 patients with the Budd-Chiari syndrome were treated surgically. Eighteen underwent a mesenterico-caval shunt (MCS); two, a side-to-side portacaval shunt; one, a mesenterico-atrial shunt (MAS); and one, a liver transplantation (OLT). One patient died after operation from the precipitating condition, and two MCS grafts that thrombosed were restored. All 21 surviving patients remain well, free from ascites, and all shunts are patent after a mean follow-up of 5.6 +/- 1 years, five patients with more than 10 years' follow-up. This long-term survival achieved by portasystemic shunts suggests that they have a major role in the treatment of the Budd-Chiari syndrome. The authors prefer the mesenterico-caval shunt using a jugular graft. This ensures a total portasystemic shunt, avoids subhepatic surgery, and reduces the long-term risk of prosthetic graft thrombosis. The MAS was reserved for cases with complete caval thrombosis. Patients with significant degrees of caval compression were satisfactorily decompressed by MCS. In patients not promptly treated, the disease progresses to cirrhosis, and such patients must be evaluated for transplantation similarly to those with other hepatopathies. Images Fig. 1. Fig. 3. Fig. 4. Fig. 5A and B. PMID:1953111

  8. Ventriculosternal Shunting for the Management of Hydrocephalus: Case Report of A Novel Technique

    PubMed Central

    Hung Pang, Peter Ka; Chan, Kwong Yau; Ching Kwok, John Kwong

    2015-01-01

    BACKGROUND: Conventional cerebrospinal fluid diversion such as ventriculoperitoneal or ventriculoatrial shunting for the management of hydrocephalus is one of the commonest neurosurgical procedures. However, in selected patients, surgical options are limited when relative contraindications for these operations exist. A patient who underwent ventriculosternal shunting, a novel procedure, is presented with durable and successful outcomes. OBJECTIVE: To demonstrate the feasibility, durability, and safety of ventriculosternal shunting for the management of hydrocephalus. METHODS: A patient with end-stage renal failure and heart failure with recurrent pleural effusion suffered from post–subarachnoid hemorrhage communicating hydrocephalus. Because of the need for continuous ambulatory peritoneal dialysis and the risk of introducing excessive cardiac preloading, conventional shunting was relatively contraindicated. Ventriculosternal shunting was performed by adopting the cancellous matrix of the sternum as the anatomic receptacle for intraosseous cerebrospinal fluid absorption. After placement of the ventricular catheter in the usual manner, the distal end was inserted into the sternum. RESULTS: There was demonstrable clinical and radiological improvement in hydrocephalus by ventriculosternal shunting. Cerebrospinal fluid intraosseous absorption by this novel procedure translated into both physical and cognitive recovery. The procedure was tolerable, effective, and durable, with the patient suffering no complications 3 years after the procedure. CONCLUSION: Ventriculosternal shunting for the management of hydrocephalus is a feasible, safe, and durable surgical treatment option for selected patients when conventional procedures are contraindicated. ABBREVIATION: VS, ventriculosternal PMID:26114598

  9. Universality of Non-Ohmic Shunt Leakage in Thin-Film Solar Cells

    SciTech Connect

    Dongaonkar, S.; Servaites, J.D.; Ford, G.M.; Loser, Stephen; Moore, J.; Gelfand, R.M.; Mohseni, H.W.; Agrawal, R.; Ratner, Mark A.; Marks, Tobin J.; Lundstrom, M.S.; Alam, M.A.

    2010-01-01

    We compare the dark current-voltage (IV) characteristics of three different thin-film solar cell types: hydrogenated amorphous silicon (a-Si:H) p-i-n cells, organic bulk heterojunction (BHJ) cells, and Cu(In,Ga)Se2 (CIGS) cells. All three device types exhibit a significant shunt leakage current at low forward bias (V<~0.4) and reverse bias, which cannot be explained by the classical solar cell diode model. This parasitic shunt current exhibits non-Ohmic behavior, as opposed to the traditional constant shunt resistance model for photovoltaics. We show here that this shunt leakage (Ish) , across all three solar cell types considered, is characterized by the following common phenomenological features: (a) voltage symmetry about V=0 , (b) nonlinear (power law) voltage dependence, and (c) extremely weak temperature dependence. Based on this analysis, we provide a simple method of subtracting this shunt current component from the measured data and discuss its implications on dark IV parameter extraction. We propose a space charge limited (SCL) current model for capturing all these features of the shunt leakage in a consistent framework and discuss possible physical origin of the parasitic paths responsible for this shunt current mechanism.

  10. Flexural wave band-gaps in phononic metamaterial beam with hybrid shunting circuits

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Wen, Ji-Hong; Chen, Sheng-Bing; Wang, Gang; Wen, Xi-Sen

    2015-03-01

    Periodic arrays of hybrid-shunted piezoelectric patches are used to control the band-gaps of phononic metamaterial beams. Passive resistive-inductive (RL) shunting circuits can produce a narrow resonant band-gap (RG), and active negative capacitive (NC) shunting circuits can broaden the Bragg band-gaps (BGs). In this article, active NC shunting circuits and passive resonant RL shunting circuits are connected to the same piezoelectric patches in parallel, which are usually called hybrid shunting circuits, to control the location and the extent of the band-gaps. A super-wide coupled band-gap is generated when the coupling between RG and the BG occurs. The attenuation constant of the infinite periodic structure is predicted by the transfer matrix method, which is compared with the vibration transmittance of a finite periodic structure calculated by the finite element method. Numerical results show that the hybrid-shunting circuits can make the band-gaps wider by appropriately selecting the inductances, negative capacitances, and resistances. Project supported by the National Natural Science Foundation of China (Grant Nos. 51275519 and 51175501).

  11. Controversies: Optic nerve sheath fenestration versus shunt placement for the treatment of idiopathic intracranial hypertension

    PubMed Central

    Spitze, Arielle; Lam, Peter; Al-Zubidi, Nagham; Yalamanchili, Sushma; Lee, Andrew G

    2014-01-01

    Background: Idiopathic intracranial hypertension (IIH) has been increasing in prevalence in the past decade, following the obesity epidemic. When medical treatment fails, surgical treatment options must be considered. However, controversy remains as to which surgical procedure is the preferred surgical option – optic nerve sheath fenestration (ONSF) or cerebrospinal fluid (CSF) shunting – for the long-term treatment of this syndrome. Purpose: To provide a clinical update of the pros and cons of ONSF versus shunt placement for the treatment of IIH. Design: This was a retrospective review of the current literature in the English language indexed in PubMed. Methods: The authors conducted a PubMed search using the following terms: Idiopathic IIH, pseudotumor cerebri, ONSF, CSF shunts, vetriculo-peritoneal shunting, and lumbo-peritoneal shunting. The authors included pertinent and significant original articles, review articles, and case reports, which revealed the new aspects and updates in these topics. Results: The treatment of IIH remains controversial and lacks randomized controlled clinical trial data. Treatment of IIH rests with the determination of the severity of IIH-related visual loss and headache. Conclusion: The decision for ONSF versus shunting is somewhat institution and surgeon dependent. ONSF is preferred for patients with visual symptoms whereas shunting is reserved for patients with headache. There are positive and negative aspects of both procedures, and a prospective, randomized, controlled trial is needed (currently underway). This article will hopefully be helpful in allowing the reader to make a more informed decision until that time. PMID:25449938

  12. Shunt Diode Designs in Li/cf Shuttle Batteries

    NASA Technical Reports Server (NTRS)

    Miller, D.; Higgins, R.

    1984-01-01

    Although Li/CF cells and batteries have an excellent safety record, they are included with other battery systems that require additional safety precautions. One precaution suggested is the inclusion of shunt diodes into these batteries. The benefits of this addition are examined. All cells tested at elevated temperatures vent regardless of length of time between being fully discharged and reversed or inclusion of the diode in the system. Cells discharged at ambient temperatures all show a relatively quick reversal, but stabilize at voltages that are high enough that the diodes are not functioning. Cells tested at depressed temperatures reverse the deepest of all cells tested, with the deepest reversal occurring very early in the test and voltages recovering to above -0.60 volts near the end of the tests. Anode limited cells will eliminate the venting during hot reversal.

  13. Electro-clinical follow-up of shunted hydrocephalic children.

    PubMed

    Varfis, G; Berney, J; Beaumanoir, A

    1977-01-01

    In a survey of 29 hydrocephalic children treated by ventriculoatrial shunt (Holter valve) with a follow-up of 4 years, EEG records before the operation and at least once a year thereafter, the authors can support the view that an epileptogenic focus has developed around the place of insertion of the ventricular catheter in 19 cases, leading to epileptic seizures in 17 up to now. Thus the incidence of convulsions in this particular group of patients is 0.59 (17/29), the limits of confidence 95% being 0.39-0.76. The irritative abnormalities occur usually during the second year after the operation and the delay for the onset of clinical seizures is variable. The age at operation seems to influence the occurrence of the epileptogenic scar. The type of hydrocephalus and especially the presence of an associated cerebral focal lesion can be of importance in the development of clinical seizures. PMID:405183

  14. Transient Hemolytic Anemia after Transjugular Intrahepatic Portosystemic Stent Shunt

    PubMed Central

    Garcia-Rebollo, Sagrario; Santolaria-Fernández, Francisco; Diaz-Romero, Francisco; Rodriguez-Moreno, Fermin; Martinez-Riera, Antonio

    1996-01-01

    Management of variceal bleeding secondary to portal hypertension constitutes a challenging issue, particularly in child's C cirrhotic patients. Recently, transjugular placement of self-expanding metallic stents in the liver (TIPS), creating a shunt between the portal and hepatic branches has provided a safe and promising therapeutic approach in this clinical situation. We report here the case of a 66-year-old male cirrhotic patient who developed a moderately severe clinical picture of a Coombsnegative hemolytic anemia (serum hemoglobin, 93 g/l, serum bilirubin 160.74 umol/L (9.4 mg/dl), indirect 6.3 mg/dl (107.73 umol/L); serum LDH 1220 u/l, reticulocytes, 5.1%. serum ferritin, 1221 ug/1, schistocytes in peripheral blood smear) the week after undergoing a TIPS, suggesting the development ofa microangiopathic hemolytic anaemia secondary to red blood cell disruption by passing through the metallic network of the stent. PMID:8809588

  15. A thiosulfate shunt in the sulfur cycle of marine sediments.

    PubMed

    Jørgensen, B B

    1990-07-13

    The oxidation of sulfide, generated by bacterial sulfate reduction, is a key process in the biogeochemistry of marine sediments, yet the pathways and oxidants are poorly known. By the use of (35)S-tracer studies of the S cycle in marine and freshwater sediments, a novel shunt function of thiosulfate (S(2)O(3)(2-)) was identified. The S(2)O(3)(2-) constituted 68 to 78 percent of the immediate HS(-)-oxidation products and was concurrently (i) reduced back to HS(-), (ii) oxidized to SO(4)(2-), and (iii) disproportionated to HS(-) + SO(4)(2-). The small thiosulfate pool is thus involved in a dynamic HS(-) - S(2)O(3)(2-) cycle in anoxic sediments. The disproportionation of thiosulfate may help account for the large difference in isotopic composition ((34)S/(32)S) of sulfate and sulfides in sediments and sedimentary rocks.

  16. Staged Transcatheter Treatment of Portal Hypoplasia and Congenital Portosystemic Shunts in Children

    SciTech Connect

    Bruckheimer, Elchanan Dagan, Tamir; Atar, Eli; Schwartz, Michael; Kachko, Ludmila; Superina, Riccardo; Amir, Gabriel; Shapiro, Rivka; Birk, Einat

    2013-12-15

    Purpose: Congenital portosystemic shunts (CPSS) with portal venous hypoplasia cause hyperammonemia. Acute shunt closure results in portal hypertension. A transcatheter method of staged shunt reduction to afford growth of portal vessels followed by shunt closure is reported. Methods: Pressure measurements and angiography in the CPSS or superior mesenteric artery (SMA) during temporary occlusion of the shunt were performed. If vessels were diminutive and the pressure was above 18 mmHg, a staged approach was performed, which included implantation of a tailored reducing stent to reduce shunt diameter by {approx}50 %. Recatheterization was performed approximately 3 months later. If the portal pressure was below 18 mmHg and vessels had developed, the shunt was closed with a device. Results: Six patients (5 boys, 1 girl) with a median age of 3.3 (range 0.5-13) years had CPSS portal venous hypoplasia and hyperammonemia. Five patients underwent staged closure. One patient tolerated acute closure. One patient required surgical shunt banding because a reducing stent could not be positioned. At median follow-up of 3.8 (range 2.2-8.4) years, a total of 21 procedures (20 transcatheter, 1 surgical) were performed. In all patients, the shunt was closed with a significant reduction in portal pressure (27.7 {+-} 11.3 to 10.8 {+-} 1.8 mmHg; p = 0.016), significant growth of the portal vessels (0.8 {+-} 0.5 to 4.0 {+-} 2.4 mm; p = 0.037), and normalization of ammonia levels (202.1 {+-} 53.6 to 65.7 {+-} 9.6 {mu}mol/L; p = 0.002) with no complications. Conclusion: Staged CPSS closure is effective in causing portal vessel growth and treating hyperammonemia.

  17. The effects of dobutamine and dopamine on intrapulmonary shunt and gas exchange in healthy humans

    PubMed Central

    Bryan, Tracey L.; van Diepen, Sean; Bhutani, Mohit; Shanks, Miriam; Welsh, Robert C.

    2012-01-01

    The development of intrapulmonary shunts with increased cardiac output during exercise in healthy humans has been reported in several recent studies, but mechanisms governing their recruitment remain unclear. Dobutamine and dopamine are inotropes commonly used to augment cardiac output; however, both can increase venous admixture/shunt fraction (Qs/Qt). It is possible that, as with exercise, intrapulmonary shunts are recruited with increased cardiac output during dobutamine and/or dopamine infusion that may contribute to the observed increase in Qs/Qt. The purpose of this study was to examine how dobutamine and dopamine affect intrapulmonary shunt and gas exchange. Nine resting healthy subjects received serial infusions of dobutamine and dopamine at incremental doses under normoxic and hyperoxic (inspired O2 fraction = 1.0) conditions. At each step, alveolar-to-arterial Po2 difference (A-aDo2) and Qs/Qt were calculated from arterial blood gas samples, intrapulmonary shunt was evaluated using contrast echocardiography, and cardiac output was calculated by Doppler echocardiography. Both dobutamine and dopamine increased cardiac output and Qs/Qt. Intrapulmonary shunt developed in most subjects with both drugs and paralleled the increase in Qs/Qt. A-aDo2 was unchanged due to a concurrent rise in mixed venous oxygen content. Hyperoxia consistently eliminated intrapulmonary shunt. These findings contribute to our present understanding of the mechanisms governing recruitment of these intrapulmonary shunts as well as their impact on gas exchange. In addition, given the deleterious effect on Qs/Qt and the risk of neurological complications with intrapulmonary shunts, these findings could have important implications for use of dobutamine and dopamine in the clinical setting. PMID:22700799

  18. A single-incision laparoscopic technique for retrieval and replacement of disconnected ventriculoperitoneal shunt tubing found in the peritoneum.

    PubMed

    Jackson, C C; Chwals, W J; Frim, D M

    2002-04-01

    A 7-year-old girl presented with signs and symptoms of increased intracranial pressure 2 years after insertion of a ventriculoperitoneal (VP) shunt. Evaluation revealed disconnection of the distal shunt catheter and migration into the peritoneal cavity. A single-incision laparoscopic procedure was performed to locate and remove the disconnected shunt tubing, and the new shunt catheter was inserted through the laparoscopic port site. Laparoscopy is being used more frequently for evaluation and repair of distal VP shunt malfunctions, but generally still requires multiple incisions for port placement and insertion of the new shunt catheter. The single-incision technique used here is technically feasible, allows excellent visualization of the peritoneal cavity and does not require any incisions beyond the previous one used for initial shunt insertion.

  19. Role of Glyoxylate Shunt in Oxidative Stress Response.

    PubMed

    Ahn, Sungeun; Jung, Jaejoon; Jang, In-Ae; Madsen, Eugene L; Park, Woojun

    2016-05-27

    The glyoxylate shunt (GS) is a two-step metabolic pathway (isocitrate lyase, aceA; and malate synthase, glcB) that serves as an alternative to the tricarboxylic acid cycle. The GS bypasses the carbon dioxide-producing steps of the tricarboxylic acid cycle and is essential for acetate and fatty acid metabolism in bacteria. GS can be up-regulated under conditions of oxidative stress, antibiotic stress, and host infection, which implies that it plays important but poorly explored roles in stress defense and pathogenesis. In many bacterial species, including Pseudomonas aeruginosa, aceA and glcB are not in an operon, unlike in Escherichia coli In P. aeruginosa, we explored relationships between GS genes and growth, transcription profiles, and biofilm formation. Contrary to our expectations, deletion of aceA in P. aeruginosa improved cell growth under conditions of oxidative and antibiotic stress. Transcriptome data suggested that aceA mutants underwent a metabolic shift toward aerobic denitrification; this was supported by additional evidence, including up-regulation of denitrification-related genes, decreased oxygen consumption without lowering ATP yield, increased production of denitrification intermediates (NO and N2O), and increased cyanide resistance. The aceA mutants also produced a thicker exopolysaccharide layer; that is, a phenotype consistent with aerobic denitrification. A bioinformatic survey across known bacterial genomes showed that only microorganisms capable of aerobic metabolism possess the glyoxylate shunt. This trend is consistent with the hypothesis that the GS plays a previously unrecognized role in allowing bacteria to tolerate oxidative stress.

  20. Severity of the ductal shunt: a comparison of different markers

    PubMed Central

    El Hajjar, M; Vaksmann, G; Rakza, T; Kongolo, G; Storme, L

    2005-01-01

    Background: When the ductus arteriosus (DA) is patent, the ductal shunt is proportional to the ratio of left ventricular output (LVO) to systemic blood flow. Systemic blood flow can be estimated by measuring flow in the superior vena cava (SVC). Objective: To re-evaluate the accuracy of standard echocardiographic markers of patent ductus arteriosus (PDA) using LVO/SVC flow ratio. Methods: Prospective study. Preterm infants of 24–30 weeks gestational age and postnatal age less than 48 hours. The following echocardiographic criteria were measured: left atrial to aortic root ratio (LA/Ao); DA diameter by B mode and colour Doppler; mean and end diastolic flow velocity of the left pulmonary artery (LPA); LVO; SVC flow. Results: Twenty three preterm infants were enrolled (median gestational age 28 weeks (range 24–30), median birth weight 840 g (500–1440)). The DA was closed in eight (mean (SD) LVO/SVC 2.4 (0.3)) and open in 15 (mean (SD) LVO/SVC 4.5 (0.6)). An LA/Ao ratio ⩾1.4, a DA diameter ⩾1.4 mm/kg, and a mean and end diastolic flow velocity of LPA respectively ⩾0.42 and ⩾0.20 m/s identified an LVO/SVC ⩾4 with a sensitivity and a specificity above 90%. Conclusion: This study indicates that LA/Ao ratio, DA diameter, and mean and end diastolic flow velocity of the LPA are accurate markers of PDA. These standard echocardiographic variables are easy to measure and need less skill and resources than direct measurements of ductal shunt. PMID:16113155

  1. Role of Glyoxylate Shunt in Oxidative Stress Response.

    PubMed

    Ahn, Sungeun; Jung, Jaejoon; Jang, In-Ae; Madsen, Eugene L; Park, Woojun

    2016-05-27

    The glyoxylate shunt (GS) is a two-step metabolic pathway (isocitrate lyase, aceA; and malate synthase, glcB) that serves as an alternative to the tricarboxylic acid cycle. The GS bypasses the carbon dioxide-producing steps of the tricarboxylic acid cycle and is essential for acetate and fatty acid metabolism in bacteria. GS can be up-regulated under conditions of oxidative stress, antibiotic stress, and host infection, which implies that it plays important but poorly explored roles in stress defense and pathogenesis. In many bacterial species, including Pseudomonas aeruginosa, aceA and glcB are not in an operon, unlike in Escherichia coli In P. aeruginosa, we explored relationships between GS genes and growth, transcription profiles, and biofilm formation. Contrary to our expectations, deletion of aceA in P. aeruginosa improved cell growth under conditions of oxidative and antibiotic stress. Transcriptome data suggested that aceA mutants underwent a metabolic shift toward aerobic denitrification; this was supported by additional evidence, including up-regulation of denitrification-related genes, decreased oxygen consumption without lowering ATP yield, increased production of denitrification intermediates (NO and N2O), and increased cyanide resistance. The aceA mutants also produced a thicker exopolysaccharide layer; that is, a phenotype consistent with aerobic denitrification. A bioinformatic survey across known bacterial genomes showed that only microorganisms capable of aerobic metabolism possess the glyoxylate shunt. This trend is consistent with the hypothesis that the GS plays a previously unrecognized role in allowing bacteria to tolerate oxidative stress. PMID:27036942

  2. Intractable seizures associated with proximal migration of a ventriculoperitoneal shunt. Case report.

    PubMed

    Yamazaki, Tomoya; Shimizu, Satoru; Sagiuchi, Takao; Iwasaki, Toshiyuki; Utsuki, Satoshi; Suzuki, Sachio; Fujii, Kiyotaka

    2005-11-01

    A 6-year-old girl, who had received a ventriculoperitoneal (VP) shunt using the Codman-Hakim programmable valve system at age 3 months, presented with intractable seizures. Neuroimaging studies showed migration of the proximal part of the system, including the prechamber, into the cranium through the right frontal burr hole. Electroencephalography showed spike-and-wave complexes in the right hemisphere including the site of the migration. The ictus was resolved following revision surgery. The clinical findings suggested the seizures were due to irritation of the brain parenchyma by the migrated system. Proximal migration of a VP shunt may cause both shunt failure and additional focal symptoms.

  3. An interesting case of screen-detected breast cancer encasing a ventriculoperitoneal shunt.

    PubMed

    Jain, Yogesh Kumar; Kokan, Jalal S

    2013-01-01

    A 67-year-old woman was diagnosed with a breast cancer via screening encasing the ventriculoperitoneal shunt. Triple assessment including MRI scan of the breast confirmed the presence of a breast mass and the tubing of the ventriculoperitoneal shunt was running directly through the mass. She underwent wide local excision of the breast cancer as well as rerouting of VP shunt as a joint procedure with the neurosurgery team and recovered uneventfully. This is a very rare and an interesting case and required management involving a different specialty.

  4. Ascites and abdominal pseudocyst: two uncommon ventriculoperitoneal shunt complications in two cases.

    PubMed

    Comba, Atakan; Gülenç, Nazlı; Çaltepe, Gönül; Dağçınar, Adnan; Yüce, Özlem; Kalaycı, Ayhan Gazi; Ulus, Aykan

    2013-01-01

    Ascites and abdominal pseudocysts (APC) are two rare complications that can occur following placement of a ventriculoperitoneal (VP) shunt. Both complications are characterized by abnormal intraperitoneal cerebrospinal fluid (CSF) collections. Although various factors have been implicated, the exact pathogenesis of the two conditions remains elusive. This paper presents two cases of VP shunt placement resulting from hydrocephaly. The first patient presented with generalized ascites and the other with APC, both of whom were six years old. APC and ascites after VP shunt placement are rare and distinct conditions; therefore, they may require different management strategies.

  5. Failure of peritoneal and gallbladder shunts in a child with craniopharyngioma.

    PubMed

    Woodfield, Julie; Magdum, Shailendra

    2013-09-01

    A 1-year-old girl with craniopharyngioma required external drainage of 40-50 mL/h of cerebrospinal fluid (CSF) after biopsy and cyst fenestration. She developed CSF ascites following insertion of a ventriculoperitoneal (VP) shunt and a distended painful gallbladder following ventriculogallbladder shunt insertion. Revision to a ventriculoatrial shunt was required. This is the first time a craniopharyngioma has been reported to cause increased CSF production. The potential mechanisms of CSF overproduction and the difficulties managing the large volume of CSF in a young child are discussed.

  6. Severe Juxtahepatic Venous Injury: Survival after Prolonged Hepatic Vascular Isolation Without Shunting

    PubMed Central

    Worthley, C. S.; Terblanche, J.

    1990-01-01

    Survival following major juxtahepatic venous injury is rare in blunt liver trauma despite the use of intracaval shunting. Prolonged liver arterial inflow control, total hepatic venous isolation and lobectomy without shunting was used in a patient to repair a combined vena caval and hepatic venous injury after blunt liver injury. An extended period of normothermic hepatic ischemia was tolerated. Early recognition of retrohepatic venous injury and temporary liver packing to control bleeding and correct hypovolemia are essential before caval occlusion. Hepatic vascular isolation without shunting is an effective simple alternative technique allowing major venous repair in complex liver trauma. PMID:2090188

  7. Testing of cerebrospinal compensatory reserve in shunted and non-shunted patients: a guide to interpretation based on an observational study.

    PubMed Central

    Czosnyka, M; Whitehouse, H; Smielewski, P; Simac, S; Pickard, J D

    1996-01-01

    OBJECTIVE--To design a computerised infusion test to compensate for the disadvantages of Katzman's lumbar infusion method: inadequate accuracy of estimation of the resistance to cerebrospinal fluid outflow and poor predictive value in normal pressure hydrocephalus. METHODS--Accuracy was improved by intracranial pressure signal processing and model analysis for measurement of cerebrospinal compensatory variable. These include the CSF outflow resistance, brain compliance, pressure-volume index, estimated sagittal sinus pressure, CSF formation rate, and other variables. Infusion may be made into the lumbar space, ventricles, or, when assessing shunt function in vivo, the shunt chamber. RESULTS AND CONCLUSIONS--The computerised test has been used for five years in a multicentre study in 350 hydrocephalic patients of various ages, aetiologies, and states of cerebrospinal compensation. The principles of using the test to characterise different types of CSF circulatory disorders in patients presenting with ventricular dilatation, including brain atrophy and normal and high pressure hydrocephalus, are presented and illustrated. Previous studies showed a positive correlation between cerebrospinal compensatory variables and the results of shunting, but such a prediction remains difficult in idiopathic normal pressure hydrocephalus, particularly in elderly patients. The technique is helpful in the assessment of shunt malfunction, including posture-related overdrainage, over-drainage related to the nocturnal B wave activity, and proximal or distal shunt obstruction. The appendix presents an introduction of the mathematical modelling of CSF pressure volume-compensation included in computerised infusion test software. Images PMID:8778261

  8. Ventriculoperitoneal shunt disconnection associated with spontaneous knot formation in the peritoneal catheter.

    PubMed

    Lo, William B; Ramirez, Roberto; Rodrigues, Desiderio; Solanki, Guirish A

    2013-01-01

    A 10-year-old girl underwent distal ventriculoperitoneal (VP) shunt revision 3 weeks earlier and developed further shunt malfunction. During the current shunt revision, a disconnection at the straight connector site in the cervical subcutaneous tissue was confirmed and a knot was identified in the peritoneal catheter. Postoperatively, the patient made a rapid neurological recovery and was discharged 48 h later. This is the first case of VP shunt disconnection associated with a spontaneous distal knot formation. The likely mechanism was that the spontaneously formed knot acted as an anchor at the peritoneal wall, preventing free relative movement of the distal catheter. The resultant tension led to failure at the weakest point of the system, resulting in a disconnection at the proximal straight connector site.

  9. Optimizing the Shunting Schedule of Electric Multiple Units Depot Using an Enhanced Particle Swarm Optimization Algorithm.

    PubMed

    Wang, Jiaxi; Lin, Boliang; Jin, Junchen

    2016-01-01

    The shunting schedule of electric multiple units depot (SSED) is one of the essential plans for high-speed train maintenance activities. This paper presents a 0-1 programming model to address the problem of determining an optimal SSED through automatic computing. The objective of the model is to minimize the number of shunting movements and the constraints include track occupation conflicts, shunting routes conflicts, time durations of maintenance processes, and shunting running time. An enhanced particle swarm optimization (EPSO) algorithm is proposed to solve the optimization problem. Finally, an empirical study from Shanghai South EMU Depot is carried out to illustrate the model and EPSO algorithm. The optimization results indicate that the proposed method is valid for the SSED problem and that the EPSO algorithm outperforms the traditional PSO algorithm on the aspect of optimality. PMID:27436998

  10. Design and test of a novel isolator with negative resistance electromagnetic shunt damping

    NASA Astrophysics Data System (ADS)

    Yan, Bo; Zhang, Xinong; Niu, Hongpan

    2012-03-01

    This paper proposes a negative resistance electromagnetic shunt damping vibration isolator and investigates the effectiveness of the isolator. The isolator consists of a shunt circuit and a pair of electromagnet and permanent magnets that are pasted onto a box-shaped spring. A kind of negative resistance shunt impedance is proposed to cancel the inherent resistance of the electromagnet. The electromechanical coupling coefficient and the electromagnetic damping force calculation formula are obtained by Biot-Savart’s law and Ampère’s law, respectively. A single degree of freedom system is employed to verify the performance of the proposed isolator. The governing equation is established. The performance of the proposed isolator under a half-cycle sine pulse is investigated and discussed. Experiments were carried out and the results agreed well with the numerical predictions. Both the results demonstrate that the negative resistance electromagnetic shunt damping vibration isolator could suppress vibration transmitted to the structure effectively.

  11. Laparoscopic Cholecystectomy for a Patient with a Lumboperitoneal Shunt: A Rare Case.

    PubMed

    Rumba, Roberts; Vanags, Andrejs; Strumfa, Ilze; Pupkevics, Andrejs; Pavars, Maris

    2016-01-01

    A rare factor that can complicate the perioperative course of laparoscopic cholecystectomy is previous placement of a lumboperitoneal (LP) shunt. Thus far, only two articles describing this situation have been published. Here, we report on a 41-year-old female patient with gallstone disease and a LP shunt placement in the preceding year due to idiopathic intracranial hypertension. It is a syndrome of increased intracranial pressure without any known cause that mainly affects young obese women. The patient was operated upon using standard port placement and peritoneal insufflation. The postoperative period was uneventful and the patient was discharged shortly after the procedure. Due to the increasing incidence and prevalence of obesity, the number of general surgical patients with a LP shunt will likely increase. Based on our experience and evidence in the literature, we conclude that performing a laparoscopy for a patient with a LP shunt is safe. PMID:27452939

  12. Optimizing the Shunting Schedule of Electric Multiple Units Depot Using an Enhanced Particle Swarm Optimization Algorithm

    PubMed Central

    Jin, Junchen

    2016-01-01

    The shunting schedule of electric multiple units depot (SSED) is one of the essential plans for high-speed train maintenance activities. This paper presents a 0-1 programming model to address the problem of determining an optimal SSED through automatic computing. The objective of the model is to minimize the number of shunting movements and the constraints include track occupation conflicts, shunting routes conflicts, time durations of maintenance processes, and shunting running time. An enhanced particle swarm optimization (EPSO) algorithm is proposed to solve the optimization problem. Finally, an empirical study from Shanghai South EMU Depot is carried out to illustrate the model and EPSO algorithm. The optimization results indicate that the proposed method is valid for the SSED problem and that the EPSO algorithm outperforms the traditional PSO algorithm on the aspect of optimality. PMID:27436998

  13. Laparoscopic Cholecystectomy for a Patient with a Lumboperitoneal Shunt: A Rare Case.

    PubMed

    Rumba, Roberts; Vanags, Andrejs; Strumfa, Ilze; Pupkevics, Andrejs; Pavars, Maris

    2016-01-01

    A rare factor that can complicate the perioperative course of laparoscopic cholecystectomy is previous placement of a lumboperitoneal (LP) shunt. Thus far, only two articles describing this situation have been published. Here, we report on a 41-year-old female patient with gallstone disease and a LP shunt placement in the preceding year due to idiopathic intracranial hypertension. It is a syndrome of increased intracranial pressure without any known cause that mainly affects young obese women. The patient was operated upon using standard port placement and peritoneal insufflation. The postoperative period was uneventful and the patient was discharged shortly after the procedure. Due to the increasing incidence and prevalence of obesity, the number of general surgical patients with a LP shunt will likely increase. Based on our experience and evidence in the literature, we conclude that performing a laparoscopy for a patient with a LP shunt is safe.

  14. Congenital extrahepatic portosystemic shunt complicated by the development of hepatocellular carcinoma.

    PubMed

    Sharma, Ruchi; Suddle, Abid; Quaglia, Alberto; Peddu, Praveen; Karani, John; Satyadas, Thomas; Heaton, Nigel

    2015-10-01

    Congenital extrahepatic portosystemic shunt, also known as Abernethy malformation, is a rare congenital malformation. It causes shunting of blood through a communication between the portal and systemic veins such as a patent ductus venous. We report 3 cases of Abernethy malformation complicated by the development of hepatocellular carcinoma. Additionally, we comprehensively reviewed all previously reported cases and highlighted common features that may help in early diagnosis and appropriate management. Patients with Abernethy malformation may have an increased propensity to develop hepatocellular carcinoma. All 5 previously reported cases, plus the three of our patients, have a type 1 (complete) shunt suggesting a role for absent portal blood flow in the pathogenesis of hepatocellular carcinoma. Congenital extrahepatic portosystemic shunt should be sought for in cases with raised serum ammonia, hepatic encephalopathy or hepatocellular carcinoma in the absence of cirrhosis. PMID:26459734

  15. Ventriculoatrial shunt infection due to Cryptococcus neoformans: an ultrastructural and quantitative microbiological study.

    PubMed

    Walsh, T J; Schlegel, R; Moody, M M; Costerton, J W; Salcman, M

    1986-03-01

    A 28-year-old man presented with hydrocephalus due to an infection by Cryptococcus neoformans involving his ventriculoatrial shunt. Ultrastructural studies of the ventriculoatrial shunt demonstrated yeastlike organisms consistent with C. neoformans within a biofilm on the appliance. Quantitative microbiological studies of segments of the shunt demonstrated C. neoformans in a concentration gradient from 9 X 10(6) colony-forming units (CFU)/0.5-cm section involving the ventricular portion of the catheter to 1 X 10(2) CFU/0.5-cm section at the vascular tip. The clinical, microbiological, and ultrastructural data suggest that this cryptococcal infection started as a ventriculitis or encephalitis with extension to the meningeal surface. Future application of these methods may further elucidate the pathogenesis of ventriculoatrial shunt infections.

  16. Anal extrusion of migrated ventriculo-peritoneal shunt catheter: An unusual complication and review of literature

    PubMed Central

    Sarkari, Avijit; Borkar, Sachin A.; Mahapatra, A. K.

    2016-01-01

    Authors present an unusual case of anal extrusion of peritoneal end of ventriculo-peritoneal shunt in a 2-year-old male child. Pertinent literature is reviewed regarding this rare complication of a very commonly performed neurosurgical procedure.

  17. Unusual Gross Pneumocephalus and Pneumoperitoneum after VP Shunt Surgery: A Case Report.

    PubMed

    A, Khanolkar; Yk, Sarin

    2015-01-01

    We report an unusual case where a two-month infant developed a simultaneous and spontaneous pneumocephalus and gross pneumoperitoneum along with progressive surgical emphysema after VP shunt procedure.

  18. Ischemic stroke patients with active malignancy or extracardiac shunts are more likely to have a right-to-left shunt found by TCD than echocardiogram.

    PubMed

    de Havenon, Adam; Moore, Anne; Sultan-Qurraie, Ali; Majersik, Jennifer J; Stoddard, Greg; Tirschwell, David

    2015-10-01

    Although the association between patent foramen ovale and ischemic stroke is controversial, the evaluation for a right-to-left shunt remains part of the standard workup for cryptogenic stroke. Transthoracic and transesophageal echocardiogram (TTE and TEE) are the screening test and gold standard to evaluate for right-to-left shunt, respectively. Studies comparing TTE or TEE to transcranial Doppler (TCD) have shown that 15-25 % of patients test positive for right-to-left shunt on TCD but are negative on TTE or TEE. We sought to further explore this phenomenon in patients with recent ischemic stroke. Between 2011 and 2013, 109 ischemic stroke patients had both a TCD and TTE or TEE bubble study. We abstracted 12 comorbid medical conditions and stroke subtype according to the TOAST classification. The majority of TCD and TTE or TEE showed agreement on right-to-left shunt status (80/109, 73 %). Two percent (2/109) of patients were negative on TCD and positive on TTE or TEE, while 25 % (27/109) had a positive TCD and negative TTE or TEE (TCD+Echo-). The TCD+Echo- patients were more likely to have active malignancy and the delayed arrival of contrast bubbles than the remainder of the cohort (15 vs. 2 %, p = 0.032; 51 vs. 18 %, p = 0.001). Our results confirm previous reports that TCD is superior to echocardiography in the detection of right-to-left shunt. The TCD+Echo- patients were more likely to have active malignancy and findings suggestive of an extracardiac shunt. These results could lead to more comprehensive evaluation for occult malignancy or a pulmonary arteriovenous malformation, both potentially treatable etiologies of ischemic stroke.

  19. Impact of shunt capacitor banks on substation surge environment and surge arrester applications

    SciTech Connect

    1996-10-01

    The introduction of high voltage shunt capacitor banks on a power system can result in a number of overvoltage problems that tend to be associated with capacitor switching. Proper application of surge arresters near a shunt capacitor bank requires careful analysis of the power system, the switching devices and their arrangements, the insulation level of nearby equipment, the type of grounding, and the arrester energy dissipation duty.

  20. Bilateral Papilledema as the First Sign of Ventriculoperitoneal Shunt Dysfunction§

    PubMed Central

    Serna-Ojeda, Juan Carlos; Aguirre-Mireles, Montserrat; Camargo-Suarez, Mayra Fabiola

    2015-01-01

    A 12 year-old girl patient with a history of ventriculoperitoneal shunt placement at the age of 6 months presented with progressive bilateral decrease in visual acuity. Ophthalmologic examination was consistent with bilateral papilledema. No other systemic manifestations of increased intracranial pressure were evident and laboratory work-up excluded other inflammatory or infectious processes. We present here an interesting case of a patient with ophthalmologic manifestations as the initial finding of ventriculoperitoneal shunt dysfunction. PMID:25834657

  1. Experimental Percutaneous Extrahepatic Portacaval Shunt Creation by Transjugular Approach in Swine

    SciTech Connect

    Seong, Chang Kyu; Pavcnik, Dusan Uchida, Barry T.; Anai, Hiroshi; Timmermans, Hans; Niyyati, Mahtab; Corless, Christopher L.; Correa, Luiz O.; Keller, Frederick S.; Roesch, Josef

    2005-06-15

    The purpose of the study was to evaluate the feasibility of the creation of a percutaneous extrahepatic portacaval shunt (PEPS) in swine by a transjugular approach and to find a suitable stent-graft to use in PEPS. In 12 swine, the extrahepatic portal vein (PV) was entered from the inferior vena cava (IVC) by a needle system introduced from the transjugular approach. A catheter introduced through the transhepatic approach served as a target. Five types of stent-graft consisting of homemade Z stents and a polytetrafluoethylene cover were explored for PEPS creation. Eight animals had follow-up venograms up to 6 weeks or until the shunt became severely stenotic. Gross and histologic examinations were performed after the final follow-up venography. The PV punctures and stent-graft placement were difficult, but the PEPS was established in all animals. In four animals, the stent-graft failed to adequately cover the tract, causing severe hemorrhage. Only two shunts remained patent up to 6 weeks. The other shunts exhibited severe stenosis or occlusion. At gross examination, all shunts traversed the liver parenchyma of the caudate lobe surrounding the IVC. The extravascular PEPS portion was 4 mm to 2 cm long. All shunts entered the PV close to the splenomesenteric junction and exhibited neointimal formation. Shunt stenoses were caused by neointimal hyperplasia and occlusions by a superimposed thrombus. PEPS can be created by the transjugular approach in swine, but only the PV shunt entrance is extrahepatic. None of the tested rigid stent-grafts were suitable for PEPS creation. A short flexible stent-graft with flanged ends is suggested for further exploration.

  2. Superconducting FCL using a combined inducted magnetic field trigger and shunt coil

    DOEpatents

    Tekletsadik, Kasegn D.

    2007-10-16

    A single trigger/shunt coil is utilized for combined induced magnetic field triggering and shunt impedance. The single coil connected in parallel with the high temperature superconducting element, is designed to generate a circulating current in the parallel circuit during normal operation to aid triggering the high temperature superconducting element to quench in the event of a fault. The circulating current is generated by an induced voltage in the coil, when the system current flows through the high temperature superconducting element.

  3. Robotic-assisted hysterectomy in a patient with a ventriculoperitoneal shunt.

    PubMed

    Bush, Stephen H; Greg Heywood, S; Calhoun, Byron C

    2011-12-01

    There are several articles in the literature reporting laparoscopic surgery in patients with ventriculoperitoneal shunts (VPSs). Although the majority of these conclude that a pneumoperitoneum in these patients is safe, there are other reports indicating possible complications of the insufflation. This is the first known report of a robotic-assisted hysterectomy performed on a patient with a VPS and the management of the shunt during the procedure. PMID:27628120

  4. Optimal Surgical Management Using a Classic Blalock-Taussig Shunt for an Infected Pseudoaneurysm After a Modified Blalock-Taussig Shunt Procedure.

    PubMed

    Okada, Noritaka; Murayama, Hiroomi; Hasegawa, Hiroki

    2016-05-01

    We present 2 cases of a 3-month-old girl and boy who were diagnosed with an infected pseudoaneurysm 2 months after undergoing left-sided modified Blalock-Taussig shunt (mBTS) operations for pulmonary atresia. Because the shunts in both cases were nearly obstructed, they underwent a 2-stage surgical approach: classic BTS operations through a right thoracotomy to establish sufficient pulmonary flow and infected graft removal through a median sternotomy after close observation of the state of the aneurysms. By utilizing autologous tissue from a different thoracic entry, both patients were successfully managed and recovered without any recurrence of infection. PMID:27106441

  5. CSF shunt infections: a fifteen-year experience with emphasis on management and outcome.

    PubMed

    Morissette, I; Gourdeau, M; Francoeur, J

    1993-05-01

    A retrospective study of patients with cerebrospinal fluid shunt infections was undertaken from 1975 to 1989 in a university hospital. The data were analyzed with emphasis on the choice of treatment and outcome. There were 44 infectious episodes in 38 patients for an overall rate of 2.6%, including 30 ventriculoperitoneal, 11 ventriculoatrial and 3 lumboperitoneal shunts. The most frequently isolated pathogens were staphylococci in 61% of the cases followed by gram-negative bacilli in 25%. Different modalities of treatment were used: support (2), intravenous antibiotics alone (6), intravenous antibiotics and shunt revision (3), intravenous antibiotics and shunt removal with or without prior externalization of the distal end (33: 13 + 20). The cure rate was 94% (31/33) with this last modality of treatment. Only 3 patients received intraventricular antibiotics. All deaths occurred in patients treated with support only (2) or with antibiotics alone (1). Four of the six recurrent episodes occurred in patients treated with antibiotics alone (2) or with a shunt revision (2). We conclude that carefully chosen intravenous antibiotics combined with shunt removal preceded or not by externalization of the distal end as an alternative therapy to repeated ventricular taps or insertion of an external ventricular drainage device is an appropriate therapy.

  6. Spontaneous bacterial peritonitis causing Serratia marcescens and Proteus mirabilis ventriculoperitoneal shunt infection. Case report.

    PubMed

    Tumialán, Luis M; Lin, Franklin; Gupta, Sanjay K

    2006-08-01

    The authors report their experience treating a polymicrobial ventriculoperitoneal (VP) shunt infection in a developmentally delayed 21-year-old woman. Cerebrospinal fluid (CSF) cultures grew Serratia marcescens and Proteus mirabilis. On admission and throughout her hospitalization, results of physical examination of her abdomen were normal, and radiographic studies showed no evidence of bowel perforation or pseudocyst formation. Contrast-enhanced computed tomography of the abdomen revealed a small fluid collection. After a course of intravenous gentamicin and imipenem with cilastatin in conjunction with intrathecal gentamicin, the infection was resolved and the VP shunt was reimplanted. Although VP shunt infections are not uncommon, S. marcescens as a causative agent is exceedingly rare and potentially devastating. Only two previous cases of S. marcescens shunt infection have been reported in the literature. Authors reporting on S. marcescens infections in the central nervous system (CNS) have observed significant morbidity and death. Although more common, the presence of P. mirabilis in the CSF is still rare and highly suggestive of bowel perforation, which was absent in this patient. Spontaneous bacterial peritonitis was the likely source from which these bacteria gained entrance into the VP shunt system, eventually causing ventriculitis in this patient. The authors conclude that in light of the high morbidity associated with S. marcescens infection of the CNS, intrathecal administration of gentamicin should be strongly considered as part of first-line therapy for S. marcescens infections in VP shunts.

  7. Mechanism for measurement of flow rate of cerebrospinal fluid in hydrocephalus shunts.

    PubMed

    Rajasekaran, Sathish; Kovar, Spencer; Qu, Peng; Inwald, David; Williams, Evan; Qu, Hongwei; Zakalik, Karol

    2014-01-01

    The measurement of the flow rate of cerebrospinal fluid (CSF) or existence of CSF flow inside the shunt tube after shunt implant have been reported as tedious process for both patients and doctors; this paper outlines a potential in vitro flow rate measurement method for CSF in the hydrocephalus shunt. The use of implantable titanium elements in the shunt has been proposed to allow for an accurate temperature measurement along the shunt for prediction of CSF flow rate. The CSF flow velocity can be deduced by decoupling the thermal transfer in the measured differential time at a pair of measurement spots of the titanium elements. Finite element analyses on the fluidic and thermal behaviors of the shunt system have been conducted. Preliminary bench-top measurements on a simulated system have been carried out. The measured flow rates, ranging from 0.5 mm/sec to 1.0 mm/sec, which is clinically practical, demonstrate good agreements with the simulation results.

  8. Hydrocephalus and Ventriculoperitoneal Shunts: Modes of Failure and Opportunities for Improvement.

    PubMed

    Jorgensen, Julianne; Williams, Corin; Sarang-Sieminski, Alisha

    2016-01-01

    Between 0.5 and 4 of every 1000 children are born with hydrocephalus. Hydrocephalus is an over-accumulation of cerebrospinal fluid (CSF) in the ventricles of the brain, which can affect cognitive function, vision, appetite, and cranial nerve function. Left untreated, hydrocephalus can result in death. The current treatment for hydrocephalus uses ventriculoperitoneal (VP) shunts with valves to redirect CSF from the ventricles into the peritoneum. Shunt technology is limited by a number of complications, which include infection after implantation, shunt obstruction due to clot formation or catheter obstruction by scar tissue or choroid plexus, disconnection and tubing migration, and overdrainage or underdrainage of CSF due to valve malfunction. While modifications to surgical procedures and shunt design have been introduced, only modest improvements in outcomes have been observed. Here we provide an overview of hydrocephalus, VP shunts, and their modes of failure, and we identify numerous areas of opportunity for biomedical engineers and physicians to collaborate to improve the performance of VP shunts.

  9. Percutaneous Retroperitoneal Splenorenal Shunt for Symptomatic Portal Vein Thrombosis After Liver Transplantation.

    PubMed

    Pulitano, C; Rogan, C; Sandroussi, C; Verran, D; McCaughan, G W; Waugh, R; Crawford, M

    2015-08-01

    Acute or recurrent bleeding from ectopic varices is a potentially life-threatening condition in rare patients with extrahepatic complete portal vein thrombosis (PVT) after liver transplantation (LT). In this setting, the role of interventional radiology is very limited and surgical shunts, in particular splenorenal shunts are usually used, despite the high associated mortality. We present the first reports of the clinical use of a new minimally invasive technique, percutaneous retroperitoneal splenorenal shunt (PRESS), in two LT recipients with life-threatening variceal hemorrhage secondary to PVT. Both patients had a successful PRESS using a transplenic approach with resolution of bleeding, avoiding the need for a potentially complicated laparotomy. The PRESS procedure is a useful addition to the interventional armamentarium that can be used in cases unsuitable for surgical shunt, and refractory to endoscopic management. In the future, this technique may be an alternative to surgical shunts as the standard procedure in patients with extra-hepatic PVT, just as the transjugular intrahepatic portosystemic shunt (TIPS) procedure has become for the management of portal hypertension in the absence of PVT. Longer-term follow-up will be needed to establish the long-term success of this procedure. PMID:25980940

  10. Standard Trabeculectomy and Ex-PRESS Miniature Glaucoma Shunt: A Comparative Study and Literature Review

    PubMed Central

    Zunz, Eran; Tzur, Rotem; Kurtz, Shimon; Shemesh, Gabi

    2015-01-01

    Purpose: The aim of this study was to compare the efficacy and safety between standard trabeculectomy and the Ex-PRESS shunt implantation. Methods: A retrospective review of the records of 100 eyes of 100 patients who underwent trabeculectomy or Ex-PRESS shunt implantation between July 2010 and June 2012 was conducted. Of these, 61 (61%) eyes underwent trabeculectomy and 39 (39%) eyes underwent Ex-PRESS shunt implantation. Demographic information, glaucoma type, surgical details, preoperative, and postoperative data including intraocular pressure (IOP), number of medications, reoperation, and occurrence of any complications were recorded. Results: No differences in IOP reduction or number of postoperative IOP-lowering medications were demonstrated between the 2 procedures. Success rates were 86.9% for trabeculectomy and 84.6% for Ex-PRESS shunt. Rates of failure and hypotony were not significantly different between the groups. No parameter was correlated with success or failure of any procedure. Conclusions: Standard trabeculectomy and Ex-PRESS shunt have similar efficacy and safety profiles. As the Ex-PRESS shunt is considerably more expensive, its use may be unjustified, especially as a primary procedure. PMID:24633088

  11. Mechanism for measurement of flow rate of cerebrospinal fluid in hydrocephalus shunts.

    PubMed

    Rajasekaran, Sathish; Kovar, Spencer; Qu, Peng; Inwald, David; Williams, Evan; Qu, Hongwei; Zakalik, Karol

    2014-01-01

    The measurement of the flow rate of cerebrospinal fluid (CSF) or existence of CSF flow inside the shunt tube after shunt implant have been reported as tedious process for both patients and doctors; this paper outlines a potential in vitro flow rate measurement method for CSF in the hydrocephalus shunt. The use of implantable titanium elements in the shunt has been proposed to allow for an accurate temperature measurement along the shunt for prediction of CSF flow rate. The CSF flow velocity can be deduced by decoupling the thermal transfer in the measured differential time at a pair of measurement spots of the titanium elements. Finite element analyses on the fluidic and thermal behaviors of the shunt system have been conducted. Preliminary bench-top measurements on a simulated system have been carried out. The measured flow rates, ranging from 0.5 mm/sec to 1.0 mm/sec, which is clinically practical, demonstrate good agreements with the simulation results. PMID:25570411

  12. Effect of rapamycin on hepatic osteodystrophy in rats with portasystemic shunting

    PubMed Central

    van der Merwe, Schalk W; Conradie, Maria M; Bond, Robert; Olivier, Brenda J; Fritz, Elongo; Nieuwoudt, Martin; Delport, Rhena; Slavik, Tomas; Engelbrecht, Gert; Kahn, Del; Shephard, Enid G; Kotze, Maritha J; de Villiers, Nico P; Hough, Stephen

    2006-01-01

    AIM: To study if T-cell activation related to portasystemic shunting causes osteoclast-mediated bone loss through RANKL-dependent pathways. We also investigated if T-cell inhibition using rapamycin would protect against bone loss in rats. METHODS: Portasystemic shunting was performed in male Sprague-Dawley rats and rapamycin 0.1 mg/kg was administered for 15 wk by gavage. Rats received powderized chow and supplemental feeds to prevent the effects of malnutrition on bone composition. Weight gain and growth was restored after surgery in shunted animals. At termination, biochemical parameters of bone turnover and quantitative bone histology were assessed. Markers of T-cell activation, inflammatory cytokine production, and RANKL-dependent pathways were measured. In addition, the roles of IGF-1 and hypogonadism were investigated. RESULTS: Portasystemic shunting caused low turnover osteoporosis that was RANKL independent. Bone resorbing cytokine levels, including IL-1, IL-6 and TNFα, were not increased in serum and TNFα and RANKL expression were not upregulated in PBMC. Portasystemic shunting increased the circulating CD8+ T-cell population. Rapamycin decreased the circulating CD8+ T-cell population, increased CD8+ CD25+ T-regulatory cell population and improved all parameters of bone turnover. CONCLUSION: Osteoporosis caused by portasystemic shunting may be partially ameliorated by rapamycin in the rat model of hepatic osteodystrophy. PMID:16874862

  13. Unusual shunt for symptomatic portal vein thrombosis after liver transplantation - Clatworthy revisited.

    PubMed

    Mali, V P; Robless, P A; Aw, M; Loh, D L; Quak, S H; Prabhakaran, K

    2012-06-01

    PV thrombosis is not an uncommon occurrence following pediatric LT. Symptomatic PHT following PV thrombosis is treated medically, surgical portosystemic shunting (mesorex, splenorenal, and mesocaval) being reserved for refractory cases. A 10-yr-old boy suffered recurrent malena and hemorrhagic shock because of chronic PV thrombosis following LT nine yr ago (1999). Extensive work-up failed to localize the bleeding source. The liver function remained normal. Initial attempts at surgical shunts failed owing to thrombosis (mesocaval 2001, splenorenal, inferior mesenteric-left renal vein, splenic-left external iliac vein 2008). In this situation, we performed a Clatworthy shunt by anastomosing the divided lower end of the LCIV to the side of SMV. There was a single, large caliber anastomosis. Post-operatively, the malena stopped completely, and clinically, there was no lower limb edema or encephalopathy. Doppler USG revealed persistence of hepatopetal flow within the portal collaterals. Follow-up at two yr reveals stable hepatic function with a patent shunt. To the best of our knowledge, we are not aware of a Clatworthy shunt being performed in a transplant setting. We reviewed the literature pertaining to this shunt in non-transplant patients with PHT.

  14. Hydrocephalus and Ventriculoperitoneal Shunts: Modes of Failure and Opportunities for Improvement.

    PubMed

    Jorgensen, Julianne; Williams, Corin; Sarang-Sieminski, Alisha

    2016-01-01

    Between 0.5 and 4 of every 1000 children are born with hydrocephalus. Hydrocephalus is an over-accumulation of cerebrospinal fluid (CSF) in the ventricles of the brain, which can affect cognitive function, vision, appetite, and cranial nerve function. Left untreated, hydrocephalus can result in death. The current treatment for hydrocephalus uses ventriculoperitoneal (VP) shunts with valves to redirect CSF from the ventricles into the peritoneum. Shunt technology is limited by a number of complications, which include infection after implantation, shunt obstruction due to clot formation or catheter obstruction by scar tissue or choroid plexus, disconnection and tubing migration, and overdrainage or underdrainage of CSF due to valve malfunction. While modifications to surgical procedures and shunt design have been introduced, only modest improvements in outcomes have been observed. Here we provide an overview of hydrocephalus, VP shunts, and their modes of failure, and we identify numerous areas of opportunity for biomedical engineers and physicians to collaborate to improve the performance of VP shunts. PMID:27652453

  15. Oculo-peritoneal shunt: draining aqueous humor to the peritoneum.

    PubMed

    Maldonado-Junyent, Ana; Maldonado-Bas, Arturo; Gonzalez, Andrea; Pueyrredón, Francisco; Maldonado-Junyent, María; Maldonado-Junyent, Arturo; Rodriguez, Diego; Bulacio, Mariano

    2015-01-01

    In 2010, there were estimated to be approximately 60.5 million people with glaucoma. This number is expected to increase to 79.6 million by 2020. In 2010, there were 8.4 million people with bilateral blindness caused by glaucoma, and this number is expected in increase to 11.2 million by 2020. Filtering implants are special devices that have been developed to reduce intraocular pressure in patients with refractory glaucoma. The success rate of these implants is relatively low, and they continue to fail over time. To avoid failure caused by the formation of scar tissue around the implants, attempts have been made to drain the aqueous humor to various sites, including the venous system, lacrimal sac, sinuses, and conjunctival fornix. Recently, a system to shunt aqueous humor from the anterior chamber to the peritoneum has been developed. The surgical technique involved in this system is a modification of the technique currently used by neurosurgeons for the treatment of hydrocephalus. We present the first case operated using this technique.

  16. Integrated fuel cell stack shunt current prevention arrangement

    DOEpatents

    Roche, Robert P.; Nowak, Michael P.

    1992-01-01

    A fuel cell stack includes a plurality of fuel cells juxtaposed with one another in the stack and each including a pair of plate-shaped anode and cathode electrodes that face one another, and a quantity of liquid electrolyte present at least between the electrodes. A separator plate is interposed between each two successive electrodes of adjacent ones of the fuel cells and is unified therewith into an integral separator plate. Each integral separator plate is provided with a circumferentially complete barrier that prevents flow of shunt currents onto and on an outer peripheral surface of the separator plate. This barrier consists of electrolyte-nonwettable barrier members that are accommodated, prior to the formation of the integral separator plate, in corresponding edge recesses situated at the interfaces between the electrodes and the separator plate proper. Each barrier member extends over the entire length of the associated marginal portion and is flush with the outer periphery of the integral separator plate. This barrier also prevents cell-to-cell migration of any electrolyte that may be present at the outer periphery of the integral separator plate while the latter is incorporated in the fuel cell stack.

  17. Chylous ascites and lymphocyst management by peritoneovenous shunt.

    PubMed

    Silk, Y N; Goumas, W M; Douglass, H O; Huben, R P

    1991-09-01

    Although lymphocyst (retroperitoneal lymphocele) is not an uncommon complication after retroperitoneal surgery, with a reported incidence ranging from 0.6% to 48%, the occurrence of chylous ascites is a rare phenomenon. Most reports are anecdotal, and hospital records list the incidence of diagnosis as 0.001% of admissions. Diagnosis of chylous ascites is usually not difficult, inasmuch as aspiration and chemical analysis of the fluid yield the answer. Visualization of retroperitoneal fluid collection by computerized tomography or ultrasonography, however, does always raise the possibility of recurrence of tumor in cases where the primary operation was for cancer. Treatment of smaller lesions can be expectant. Respiratory exercises causing an increase in negative intrathoracic pressure may aid in the movement of fluid through the lymphatics. For larger collections, elemental diets and total parenteral nutrition are also often enough, but surgery is sometimes required. Simple insertion of a peritoneovenous shunt, as in this patient, can be as effective as major operations such as identification and ligation of the offending lymphatic or marsupialization of the cyst.

  18. Hyperglucagonemia and hyperkinetic circulation after portocaval shunt in the rat

    SciTech Connect

    Kravetz, D.; Arderiu, M.; Bosch, J.; Fuster, J.; Visa, J.; Casamitjana, R.; Rodes, J.

    1987-02-01

    The study was aimed at investigating whether increased portal venous inflow (PVI) after portocaval shunt (PCS) in the rat is the result of selective splanchnic vasodilatation or whether it is part of a generalized circulatory disturbance. Rats with PCS and sham-operated controls were studied 2 wk after surgery by measuring cardiac output (CO), PVI, and hepatic artery flow (HAF) with radioactive microspheres (V Cr and UC). Plasma glucagon (GL) was measured by radioimmunoassay. PCS rats had increased CO and reduced arterial pressure and total peripheral resistance. PVI was markedly increased, but this appeared to be part of a generalized circulatory disturbance, since when PVI is expressed as percent of CO no difference is observed between PCS and sham-operated rats, indicating the absence of a preferential splanchnic vasodilatation. GL increased after PCS, and significant correlations were observed between GL and CO and between GL and PVI. HAF increased after PCS but did not compensate the loss of portal flow, evidence by a lower total hepatic flow in PCS rats. These results suggest that PCS induces a hyperkinetic circulatory state in which increased PVI represents its splanchnic manifestation and that increased GL release may be in part responsible for these hemodynamic changes.

  19. Effects of isradipine and other calcium antagonists on arteriovenous-shunt flow in anesthetized rabbits and cats

    SciTech Connect

    Hof, R.P.

    1989-04-17

    The effects of vasodilators on arteriovenous (AV)-shunt flow was investigated in anesthetized cats and rabbits, using the tracer microsphere method. In cats, the calcium antagonist isradipine reduced AV-shunt flow; verapamil showed a similar tendency and nicardipine was without effect. Dihydralazine strongly increased, but nitroglycerin and dipyridamole decreased AV-shunt flow. In rabbits, the effects of isradipine and verapamil were similar to those seen in cats. Sodium nitroprusside had no effect, whereas prazosin, minoxidil, and the potassium-channel activator cromakalim increased AV-shunt flow. The contrasting effects of drugs sharing the same mechanism of action suggest that target-tissue selectivity is more important than the mechanism of action. An increase of AV-shunt flow is unlikely to be beneficial but could be associated with a number of undesirable side effects. It might negatively affect migraine sufferers and, if AV-shunt dilatation shows no tolerance development, it represents an unnecessary hemodynamic burden for the heart.

  20. Isolated left homonymous hemianopia secondary to a pericatheter cyst-a rare presentation of a ventriculoperitoneal shunt failure.

    PubMed

    Watkins, Jordan D; Lee, Janet; Van Engen, Meagan J; Tibbs, McKenzie L; Ellegala, Dilantha B; Nicholas, Joyce S

    2015-03-01

    A 26-year-old woman developed a left homonymous hemianopia 1 week after placement of a ventriculoperitoneal shunt through a right parieto-occipital approach. Computed tomography demonstrated a parenchymal cyst in the right occipital lobe. After shunt revision, there was concomitant resolution of the cyst and visual field defect over 1 month. The literature is reviewed regarding this unusual complication of ventriculoperitoneal shunt failure. PMID:25426733

  1. Ventriculo-bipleural shunt as last resort in a 4-year-old child in whom a VP and VA shunt failed.

    PubMed

    Ratliff, Miriam; Unterberg, Andreas; Bächli, Heidi

    2016-03-01

    The authors present the unusual case of a 4-year-old boy who had a complex history of posthemorrhagic hydrocephalus and who underwent more than 40 surgeries related to this condition. In the course of trying to treat his condition, ventriculoperitoneal, ventriculoatrial, and ventriculopleural shunts were inserted and failed. The child presented with a dysfunction of his shunt system. A ventriculopleural shunt was inserted, but within days the patient developed dyspnea as a clinical symptom of pleural effusion that required repeated thoracentesis. A bipleural drainage system was inserted, and no relevant pleural effusions developed during the follow-up period. Although the authors' experience is based on a single case, they do suggest bipleural drainage in patients with clinically relevant pleural effusions when the more common alternatives are not a good choice. Bipleural drainage might particularly be an option in children, who are prone to pleural effusion because of the smaller absorbing pleural surface. The authors reviewed the English-language literature on PubMed dating back to 1952. To their knowledge, this is the only published case in which a patient was treated with a ventriculo-bipleural shunt.

  2. Implementation of an artificial neuronal network to predict shunt necessity in carotid surgery.

    PubMed

    Aleksic, Marko; Luebke, Thomas; Heckenkamp, Joerg; Gawenda, Michael; Reichert, Viktor; Brunkwall, Jan

    2008-09-01

    In carotid surgery, it could be useful to know which patient will tolerate carotid cross-clamping in order to minimize the risks of perioperative strokes. In this clinical study, an artificial neuronal network (ANN) was applied and compared with conventional statistical methods to assess the value of various parameters to predict shunt necessity. Eight hundred and fifty patients undergoing carotid endarterectomy for a high-grade internal carotid artery stenosis under local anesthesia were analyzed regarding shunt necessity using a standard feed-forward, backpropagation ANN (NeuroSolutions); NeuroDimensions, Gainesville, FL) with three layers (one input layer, one hidden layer, one output layer). Among the input neurons, preoperative clinical (n = 9) and intraoperative hemodynamic (n = 3) parameters were examined separately. The accuracy of prediction was compared to the results of a regression analysis using the same variables. In 173 patients (20%) a shunt was used because hemispheric deficits or unconsciousness occurred during cross-clamping. With the ANN, not needing a shunt was predicted by preoperative and intraoperative parameters with an accuracy of 96% and 91%, respectively, where the regression analysis showed an accuracy of 98% and 96%, respectively. Those patients who needed a shunt were identified by preoperative parameters in 9% and by intraoperative parameters in 56% when the ANN was used. Regression analysis predicted shunt use correctly in 10% using preoperative parameters and 41% using intraoperative parameters. Intraoperative hemodynamic parameters are more suitable than preoperative parameters to indicate shunt necessity where the application of an ANN provides slightly better results compared to regression analysis. However, the overall accuracy is too low to renounce perioperative neuromonitoring methods like local anesthesia.

  3. The Budd-Chiari syndrome. Treatment by mesenteric-systemic venous shunts.

    PubMed Central

    Cameron, J L; Herlong, H F; Sanfey, H; Boitnott, J; Kaufman, S L; Gott, V L; Maddrey, W C

    1983-01-01

    Twelve patients with the Budd-Chiari syndrome have been managed surgically. Ten of the patients were female, two were male, with a mean age of 40 years. Three of the patients had polycythemia vera, two had pre-existing cirrhosis, one had ingested estrogens, one had an occult tumor, and in four there were no associated factors. Ten patients presented with ascites and two with bleeding esophageal varices. The diagnosis was confirmed in all 12 patients by liver biopsy and hepatic vein catheterization. Inferior vena cavography revealed the abdominal vena cava to be thrombosed in six patients. The superior mesenteric vein was used to decompress the congested liver in all 12 patients. In five patients, a mesocaval shunt (MCS) was performed and in seven patients, a mesoatrial shunt (MAS) was carried out. There were four hospital deaths (two MCS, two MAS). One late death (MAS) occurred from liver failure following shunt thrombosis. Two additional patients (one MCS, one MAS) re-developed ascites immediately following surgery and angiography revealed a thrombosed shunt. Ascites has been controlled with a LeVeen shunt in these two patients, but liver biopsies showed progression to cirrhosis. The remaining five patients (three MAS, two MCS) did well, and angiography revealed patent shunts. Two of these patients, however, re-developed ascites at 4 and 10 months following MAS and required a second MAS. Follow-up ranges from 6 to 68 months. In three of the patients (two MCS, one MAS) with patent shunts, liver biopsy shows a remarkable return toward normal liver architecture and histology. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. PMID:6615056

  4. T1-201 per rectum: A noninvasive method for evaluating portosystemic shunt

    SciTech Connect

    Verdickt, X.; Reding, P.; Tshiamala, P.; Ham, H.R.

    1984-01-01

    Portosystemic shunt is one of the most important complications of liver cirrhosis. Unfortunately, current methods for detecting and quantifying this shunt are either non-specific or associated with significant morbidity. The aim of this work was to evaluate the clinical value of a new non-traumatic method which consisted of administrating T1-201 per rectum and monitoring the absorbed activity using a camera and a computer system. The method assumes that in the absence of portosystemic shunt, most of the absorbed activity will be fixed in the liver while in the presence of this shunt, some of the activity will be fixed in the myocardium. The ratio of heart to liver activity can therefore be used to evaluate the importance of the portosystemic shunt. 34 subjects have been studied. The ratio of heart to liver activity at the 25th minute after the tracer administration is higher in patients with liver cirrhosis (n=22, m=.9, s.d.=.37) than in patients with steatosis (n=10, m=.28, s.d.=.03). In two healthy subjects investigated the H/L ratio was .27 and .30. The reproducibility of the test was evaluated in 8 subjects and showed a good reproducibility (mean of difference =.03, range=.01 to .07). Patients with esophageal varices had always a high H/L ratio while some patients with liver cirrhosis without esophageal varices had also high H/L ratio, probably due to the presence of intrahepatic shunt. The authors' results showed the value of this new non-traumatic test for detecting and quantifying extra- as well as intrahepatic portosystematic shunt.

  5. Diminished plantar grasp response as an additional indicator of a shunt malfunction in a case of congenital hydrocephalus.

    PubMed

    Futagi, Y; Morimoto, K

    2001-06-01

    A male infant with congenital hydrocephalus who had undergone ventriculoperitoneal (VP) shunting at 3 days of life exhibited a diminished plantar grasp response (PGR) from 2 months of age, which had clearly recovered 3 months after a shunt revision at 6 months of age. The diminished PGR was the only overt neurological sign in this patient. The precipitous decrease in PGR that occurs during early infancy in a hydrocephalic infant with VP shunting is a possible indicator of a prespastic condition caused by a shunt malfunction.

  6. Post-TIPS Hepatic Encephalopathy Treated by Occlusion Balloon-Assisted Retrograde Embolization of a Coexisting Spontaneous Splenorenal Shunt

    SciTech Connect

    Shioyama, Yasukazu; Matsueda, Kiyoshi; Horihata, Koushi; Kimura, Masashi; Nishida, Norifumi; Kishi, Kazushi; Terada, Masaki; Sato, Morio; Yamada, Ryusaku

    1996-11-15

    A 51-year-old man with posthepatitis cirrhosis underwent a transjugular intrahepatic portosystemic shunt (TIPS) for bleeding of recurrent esophageal varices. The patient had a coexisting, spontaneous, splenorenal shunt. He subsequently developed hepatic encephalopathy, presumably due to excessive portosystemic shunting. Since medical management resulted in no significant improvement, the splenorenal shunt was embolized from the jugular vein approach via renal vein access during temporary balloon occlusion. Within a few days, the patient's hepatic encephalopathy resolved. Twelve months later the patient showed no recurrence of encephalopathy and had maintained a patent TIPS.

  7. Ventriculoperitoneal shunt for hydrocephalus caused by central nervous system metastasis.

    PubMed

    Lee, Seung Hoon; Kong, Doo Sik; Seol, Ho Joon; Nam, Do-Hyun; Lee, Jung-Il

    2011-09-01

    The development of better diagnostic tools and therapeutic modalities has increased the incidence of central nervous system (CNS) metastasis in malignant tumor patients. Hydrocephalus can result from CNS metastasis and frustrate cancer treatment. The authors sought to investigate the outcomes and the roles of ventriculoperitoneal shunts (VPS) in patients with CNS metastasis. The medical records of 50 consecutive patients who underwent VPS for hydrocephalus related to CNS metastasis were analyzed retrospectively. Data included features of primary malignancies, CNS involvement, clinical course and surgical outcome. Median patient age was 55.0 years (range 25-77), and 30 female and 20 male patients were included in the study. At the time of VPS, 10 patients had parenchymal metastases only and 40 patients had leptomeningeal seeding (LMS). Symptom improvement was observed postoperatively in 40 patients (80%), mean Karnofsky performance status (KPS) scale change was from 37.8 to 46.0, and median survival from VPS was 3.0 months (2 days to 54 months). A ventricular opening pressure of >30 cmH(2)O (HR 6.44, 95% CI 1.26-32.9, P = 0.02) and further cancer treatment after VPS (HR 0.17, 95% CI 0.07-0.42, P < 0.0001) were found to be independent risk factors of poorer and better survival, respectively. Hydrocephalus in CNS metastasis requiring VPS is commonly associated with LMS. VPS is an effective palliative measure and an adequate cancer treatment after VPS may provide the best means of improving survival.

  8. Complete Intestinal Obstruction and Necrosis as a Complication of a Ventriculoperitoneal Shunt in Children

    PubMed Central

    Zhao, Rui; Shi, Wei; Yu, Jianzhong; Gao, Xiaofeng; Li, Hao

    2015-01-01

    Abstract Ventriculoperitoneal (VP) shunt complications are common, but abdominal complications are rare. The objective of this report is to present 2 cases of intestinal obstruction due to a VP shunt and review the literature for data on this rare occurrence. A 4-month-old boy received surgical resection of a medulloblastoma and a VP shunt was inserted to manage progressive hydrocephalus. Two months later, he was admitted with intermittent vomiting, and plain abdominal radiography showed complete intestinal obstruction. Emergency laparotomy revealed an adhesive intestinal obstruction around the catheter, and approximately 5 cm of necrotic ileum was resected. His recovery was uneventful. In the second case, a 6-year-old boy was diagnosed with a primary nongerminomatous malignant germ cell tumor and a VP shunt was place to treat hydrocephalus. Two weeks after the first course of chemotherapy, he went into a coma; computed tomography demonstrated enlargement of the tumor and gross total resection was performed. Two weeks later, he developed abdominal distention; plain radiography showed intestinal obstruction and laparotomy revealed adhesive intestinal obstruction around the catheter with 15 cm of necrotic ileum. The necrotic bowel was resected. Unfortunately, the patient developed sepsis and despite treatment remained in a vegetative state. Medline, Central, Embase, and Google Scholar databases were searched up to May 9, 2014, using the terms VP shunt, shunting, and/or intestinal obstruction. Only cases involving children or adolescents were included. Eleven reports involving patients with abdominal complications resulting from a VP shunt for hydrocephalus were identified. The dates of the reports spanned from 1971 to 2014. Volvulus was the most common cause of VP shunt-related obstruction, and mechanical obstruction due to twisting of the catheter the second most common. Only 1 case in the literature review was related to intestinal adhesions. Treatment in most

  9. Cerebral oxygenation and processed EEG response to clamping and shunting during carotid endarterectomy under general anesthesia.

    PubMed

    Perez, William; Dukatz, Christopher; El-Dalati, Sami; Duncan, James; Abdel-Rasoul, Mahmoud; Springer, Andrew; Go, Michael R; Dzwonczyk, Roger

    2015-12-01

    Clamping and shunting during carotid endarterectomy (CEA) surgery causes changes in cerebral blood flow. The purpose of this study was to assess and compare, side by side, the cerebral oxygenation (rSO2) and processed electroencephalogram (EEG) response bilaterally to carotid artery clamping and shunting in patients undergoing CEA under general anesthesia. With institutional approval and written informed consent, patients undergoing CEA under general anesthesia and routine carotid artery shunting were recorded bilaterally, simultaneously and continuously with an rSO2 and processed EEG monitor. The response of the monitors during carotid artery clamping and shunting were assessed and compared between monitors and bilaterally within each monitor. Sixty-nine patients were included in the study. At clamping the surgical-side and contralateral-side rSO2 dropped significantly below the baseline incision value (-17.6 and -9.4% respectively). After shunting, the contralateral-side rSO2 returned to baseline while the surgical-side rSO2 remained significantly below baseline (-9.0%) until the shunt was removed following surgery. At clamping the surgical-side and contralateral-side processed EEG also dropped below baseline (-19.9 and -20.6% respectively). However, following shunt activation, the processed EEG returned bilaterally to baseline. During the course of this research, we found the rSO2 monitor to be clinically more robust (4.4% failure rate) than the processed EEG monitor (20.0% failure rate). There was no correlation between the rSO2 or processed EEG changes that occurred immediately after clamping and the degree of surgical side stenosis measured pre-operatively. Both rSO2 and processed EEG respond to clamping and shunting during CEA. Cerebral oximetry discriminates between the surgical and contralateral side during surgery. The rSO2 monitor is more reliable in the real-world clinical setting. Future studies should focus on developing algorithms based on these

  10. Micro-fabricated shunt to mimic arachnoid granulations for the treatment of communicating hydrocephalus.

    PubMed

    Kralick, Francis; Oh, Jonghyun; Medina, Tim; Noh, Hongseok Moses

    2012-01-01

    Hydrocephalus is the abnormal accumulation of cerebrospinal fluid (CSF) within the confines of the skull that if left untreated results in significant morbidity and mortality. The treatment for hydrocephalus has remained essentially unchanged for over 50 years. It was a technological advance in materials that allowed John Holter, in conjunction with neurosurgeons Spitzer and Nulsen, to devise a valve and shunt system that diverted excess CSF from the ventricular space to the peritoneum. This ventriculo-peritoneal (VP) shunt is far from ideal, with problems associated with under/over shunting, mechanical mismatch, infection, high failure rates, disconnection and erosion. With the advances in the field of micro-fabrication and micro-machines we propose an innovative shunt system that would mimic the function of arachnoid granulations. This micro-fabricated shunting device, or micro-mechanical arachnoid granulation (MAG), consists of a multiplicity of micro-valves each 210 μm in diameter that each adhere to individual micro-needles. This work demonstrates the design and initial test results of the micro-valve with parameters for low cracking pressure, optimal flow rate, and reflux that would mimic the function of the native arachnoid granulations.

  11. Vesical calculi formation on the slit valves of a migrated distal end of ventriculoperitoneal shunt

    PubMed Central

    Gupta, Rahul; Dagla, Rajan; Agrawal, Lila Dhar; Sharma, Pramila

    2015-01-01

    Various complications of distal end of the ventriculoperitoneal (VP) shunt have been described in the literature. We present, here, an extremely rare and potentially severe complication of vesical calculi formation on the slit valves of distal end of VP shunt which erosively migrated into the urinary bladder. Suprapubic cystolithotomy performed, peritoneal end of the tube found to be eroding and entering into the bladder with two calculi firmly stuck to slit valves in the distal end of the tubing were removed. Shunt was functional, therefore, it was pulled out and repositioned on the superior aspect of the liver; the urinary bladder was repaired. Patient did well postoperatively. This complication was revealed 1.5 years after the shunt was implanted. Although there were symptoms of dysuria and dribbling of urine of short duration, the patient did not show obvious peritoneal signs; suggesting that, penetration of a VP shunt into the urinary bladder can remain asymptomatic for a long period of time, disclosed late and can lead to considerable morbidity. Careful follow-up is important and management should be individualized. PMID:26962346

  12. Hypoxia and GABA shunt activation in the pathogenesis of Alzheimer's disease.

    PubMed

    Salminen, Antero; Jouhten, Paula; Sarajärvi, Timo; Haapasalo, Annakaisa; Hiltunen, Mikko

    2016-01-01

    We have previously observed that the conversion of mild cognitive impairment to definitive Alzheimer's disease (AD) is associated with a significant increase in the serum level of 2,4-dihydroxybutyrate (2,4-DHBA). The metabolic generation of 2,4-DHBA is linked to the activation of the γ-aminobutyric acid (GABA) shunt, an alternative energy production pathway activated during cellular stress, when the function of Krebs cycle is compromised. The GABA shunt can be triggered by local hypoperfusion and subsequent hypoxia in AD brains caused by cerebral amyloid angiopathy. Succinic semialdehyde dehydrogenase (SSADH) is a key enzyme in the GABA shunt, converting succinic semialdehyde (SSA) into succinate, a Krebs cycle intermediate. A deficiency of SSADH activity stimulates the conversion of SSA into γ-hydroxybutyrate (GHB), an alternative route from the GABA shunt. GHB can exert not only acute neuroprotective activities but unfortunately also chronic detrimental effects which may lead to cognitive impairment. Subsequently, GHB can be metabolized to 2,4-DHBA and secreted from the brain. Thus, the activation of the GABA shunt and the generation of GHB and 2,4-DHBA can have an important role in the early phase of AD pathogenesis. PMID:26617286

  13. Radionuclide quantitation of right-to-left intracardiac shunts in children

    SciTech Connect

    Peter, C.A.; Armstrong, B.E.; Jones, R.H.

    1981-09-01

    A simple, noninvasive method for measurement of right-to-left intracardiac shunts would enhance the management of patients with congenital heart disease. This study describes application of data processing techniques used previously in dye-indicator curves to data recorded during the initial transit of radioactive bolus through the central circulation. Radionuclide angiocardiograms were performed in 20 children, mean age 30 months, immediately after cardiac catheterization for congenital heart disease. The radionuclide data recorded over the carotid artery were used to replace arterial sampling required for dye indicators, and forward triangles were fitted to calculate the right-to-left shunt in an approach similar to that of Wood for indicator-dilution curves. Ten of the children had right-to-left shunts by Fick and radionuclide measurement, and 10 of the children with septal defects had no right-to-left shunt by either technique. Both the radionuclide and Fick measurements correlated well (r . 0.95). Therefore, radionuclide angiocardiographic data may be used for accurate calculation of right-to-left shunts in small children, eliminating the need for arterial sampling.

  14. Few Patient, Treatment, and Diagnostic or Microbiological Factors, Except Complications and Intermittent Negative Cerebrospinal Fluid (CSF) Cultures During First CSF Shunt Infection, Are Associated With Reinfection

    PubMed Central

    Simon, Tamara D.; Mayer-Hamblett, Nicole; Whitlock, Kathryn B.; Langley, Marcie; Kestle, John R. W.; Riva-Cambrin, Jay; Rosenfeld, Margaret; Thorell, Emily A.

    2014-01-01

    Background The relationship between first and subsequent cerebrospinal fluid (CSF) shunt infections is poorly understood. By understanding the factors associated with increased risk of reinfection, researchers may provide optimal treatment strategies at the time of first infection. The objective of this study was to describe and compare children with and without CSF shunt reinfection. Methods A retrospective cohort study was performed among 118 children who underwent initial CSF shunt placement and developed first CSF shunt infection. The primary outcome variable was CSF shunt reinfection. Patient risk factors and medical and surgical management of initial CSF shunt placement and first CSF shunt infection were compared between children with and without reinfection. Results Of 118 children with first infection, 31 (26%) developed a reinfection during the study period (overall median follow-up, 2096 days). Factors associated with reinfection in this cohort included ventriculoatrial or complex shunt at initial CSF shunt placement, complications after first CSF shunt infection, and intermittent negative CSF cultures. Conclusions Few patient or treatment factors were associated with reinfection. Factors associated with difficult-to-treat first CSF shunt infection, including complications after first CSF shunt infection and intermittent negative CSF cultures, were associated with reinfection. Clinicians who treat patients with unusual CSF shunts or more difficult first infections should have a high index of suspicion for reinfection after treatment is completed. PMID:24567841

  15. Ventriculoperitoneal shunt failure causing myelopathy in a patient with bilateral jugular vein occlusion. Case report.

    PubMed

    Humphries, William E; Grossi, Peter M; Liethe, Linda G; George, Timothy M

    2007-01-01

    The authors describe the case of a 36-year-old woman with bilateral internal jugular vein occlusion, hydrocephalus, and Dandy-Walker variant who presented with myelopathy that was ultimately attributed to ventriculoperitoneal (VP) shunt failure. Computed tomography (CT) angiography of the head and neck revealed epidural venous engorgement within the cervical spine, greater that 50% narrowing of the C2-5 spinal canal, and compression of the cervical spinal cord. After successful shunt revision, postoperative CT angiography revealed decreased venous engorgement as well as decompression of the cervical spinal cord, and the patient's myelopathy improved. This case represents a fascinating clinical presentation of VP shunt failure, highlighting the physiological importance of the external jugular pathways involved in cerebral venous drainage.

  16. A knot in the catheter--an unusual cause of ventriculo-peritoneal shunt blockage.

    PubMed

    Chopra, I; Gnanalingham, K; Pal, D; Peterson, D

    2004-09-01

    A 25-year-old woman, who was 25 weeks pregnant, underwent insertion of a VP shunt for hydrocephalus, secondary to a bithalamic glioma. Two months later, she represented with symptoms of raised intracranial pressure and MR scan revealed increased ventricular size. On exploration of the shunt, manometry with saline confirmed blockage of the catheter distal to the valve. On re-opening the abdominal wound, the peritoneal catheter was found to be knotted, 2 cm from the end. This segment of the catheter was replaced, with resolution of symptoms, post-operatively. The present case illustrates that a knot in the peritoneal catheter is an extremely rare cause of shunt malfunction. Possible mechanisms underlying it are discussed.

  17. Delayed Intracerebral Hemorrhage Secondary to Ventriculoperitoneal Shunt: A Case Report and Literature Review.

    PubMed

    Ma, Li; Chen, Yi-Li; Yang, Shu-Xu; Wang, Yi-Rong

    2015-11-01

    The ventriculoperitoneal (VP) shunt is a routine procedure for cerebrospinal fluid (CSF) diversion, and is associated with many complications. A delayed hemorrhage after the VP shunt surgery, however, is quite rare. In this study, we report a case involving late-onset hemorrhage. The 67-year-old male patient with a history of head trauma and brain surgery underwent a VP shunt placement for hydrocephalus. The surgery course was uneventful and no bleeding was revealed in the first computed tomographic (CT) scan after the procedure. However, a massive intraparenchymal and intraventricular hemorrhage occurred 8 h following adjustment of the valve system on the 8th day after surgery.Erosion of the vasculature by catheter cannulation and a sudden reduction of CSF pressure after downregulation of the valve could be one of the possible causes of the intracerebral hemorrhage (ICH).

  18. Delayed-onset endophthalmitis associated with Ex-PRESS mini glaucoma shunt®.

    PubMed

    Ahmed, Yasir; Pathengay, Avinash; Flynn, Harry W; Isom, Ryan

    2012-01-01

    The authors describe a 92-year-old man who developed delayed-onset endophthalmitis secondary to Bacillus sp. in his left eye 3 years after placement of an Ex-PRESS mini glaucoma shunt (Optonol Ltd., Neve Ilan, Israel). Seidel testing was positive over the Ex-PRESS mini glaucoma shunt. The patient underwent vitreous tap followed by intravitreal injections of vancomycin (1 mg/0.1 mL), ceftazadime (2.25 mg/0.1 mL), and dexamethasone (0.4 mg/0.1 mL), along with subconjunctival injection of vancomycin and tobramycin. The last recorded visual acuity was 3/200 in the left eye. With a 1-month follow-up, this case illustrates successful treatment with a vitreous tap and injection of intravitreal antibiotics. Vitrectomy and removal of the Ex-PRESS mini glaucoma shunt were not performed. PMID:22785601

  19. A 100 GHz Josephson mixer using resistively-shunted Nb tunnel junctions

    NASA Technical Reports Server (NTRS)

    Schoelkopf, R. J.; Phillips, T. G.; Zmuidzinas, J.

    1993-01-01

    The authors describe preliminary mixer results using resistively shunted Nb/AlO(x)/Nb tunnel junctions in a 100-GHz waveguide mixer mount. The mixer utilizes robust, lithographically defined devices which have nonhysteretic I-V curves. A receiver temperature of 390 K (DSB) has been obtained with a conversion loss of -6.5 dB. The receiver's behavior agrees qualitatively with the behavior predicted by the resistively shunted junction model. Substantial improvements in performance are expected with the use of better-optimized shunted junctions, and numerical simulations suggest that, if devices with higher ICRN (critical current-normal state resistance) products can be obtained, Josephson effect mixers could be competitive with SIS mixers at high frequencies.

  20. PI and fuzzy logic controllers for shunt Active Power Filter--a report.

    PubMed

    P, Karuppanan; Mahapatra, Kamala Kanta

    2012-01-01

    This paper presents a shunt Active Power Filter (APF) for power quality improvements in terms of harmonics and reactive power compensation in the distribution network. The compensation process is based only on source current extraction that reduces the number of sensors as well as its complexity. A Proportional Integral (PI) or Fuzzy Logic Controller (FLC) is used to extract the required reference current from the distorted line-current, and this controls the DC-side capacitor voltage of the inverter. The shunt APF is implemented with PWM-current controlled Voltage Source Inverter (VSI) and the switching patterns are generated through a novel Adaptive-Fuzzy Hysteresis Current Controller (A-F-HCC). The proposed adaptive-fuzzy-HCC is compared with fixed-HCC and adaptive-HCC techniques and the superior features of this novel approach are established. The FLC based shunt APF system is validated through extensive simulation for diode-rectifier/R-L loads.

  1. A Shunt Model of the Inner Medullary Nephron with Pre-Bend Transitions

    NASA Astrophysics Data System (ADS)

    Gonzalez, M. T.; Hegarty, A. F.; Thomas, S. R.

    2009-09-01

    Mathematical models of the renal medulla face the problem of representing water and solute transfer among tens of thousands of nephrons and blood vessels of various lengths, arranged in countercurrent fashion. Published models fall into two broad categories with respect to this issue: multi-nephron models, which explicitly represent a large number of individual nephrons, or lumped models with virtual shunts that represent the turning back of nephrons and vessels at varying depths. Shunt models have the advantage of a compact description and relatively rapid execution time but are ill-suited to faithfully represent features such as prebend transitions of epithelial permeabilities in nephrons of different lengths. A new shunt model approach that can accommodate pre-bend transitions of nephrons at all medullary depths is presented in this work together with the results of simulation of predicted flows and concentrations.

  2. Wave propagation in beams with anti-symmetric piezoelectric shunting arrays

    NASA Astrophysics Data System (ADS)

    Sheng-Bing, Chen; Gang, Wang

    2016-03-01

    Piezoelectric shunting arrays are employed to control the wave propagation in flexible beams. Contrary to conventional symmetric configuration, a substrate beam with anti-symmetric shunting arrays is investigated by adapted transfer matrix method. Compared with symmetric scheme, the anti-symmetric one demonstrates some distinctive characteristics. Primarily, the longitudinal and flexural waves are coupled, so they are correlated and must be considered simultaneously. Moreover, the attenuation of flexural wave is much stronger in anti-symmetric scenario, while the longitudinal wave demonstrates the converse side. As a result, the anti-symmetric scheme can be utilized to improve the vibration isolation capability of shunting arrays. Finally, the theoretical analyses are validated by finite element simulations. Project supported by the National Natural Science Foundation of China (Grant No. 51322502).

  3. Comparative study of two structures of shunt active filter suppressing particular harmonics

    NASA Astrophysics Data System (ADS)

    Benchaita, L.; Salem Nia, A.; Saadate, S.

    1998-07-01

    This paper deals with the study of shunt active filters used for suppressing particular harmonics generated by nonlinear loads in utility distribution power systems. Both structures of shunt active filter, voltage source active filter (VSAF) and current source active filter (CSAF), are considered. The analytical study of specific harmonics identification in a given spectrum is first presented. For simulation as well as experimentation the nonlinear load is a conventional three phase thyristor rectifier and harmonics 5 and 7 are selected to be eliminated by active filter. The whole system consisting of the ac power supply network, the SCR rectifier and the shunt active filter (VSAF/CSAF) is then simulated. The simulation results are discussed and the efficiency of the two kinds of active filter are compared. Finally, for the first structure, VSAF, the simulation results are confirmed by experimental test realized by means of a fully digital control active power filter developed in our laboratory.

  4. Application considerations and compensation characteristics of shunt active and series active filters in power systems

    SciTech Connect

    Peng, Fang Zheng; Lai, Jih-Sheng

    1996-10-01

    This paper characterizes typical nonlinear loads into two types of harmonic sources -harmonic current source and harmonic voltage source, which produce highly distorted currents and voltages, respectively. The conventional approach of active harmonic compensation has been the parallel type or `shunt active filter.` It is shown in this paper that the shunt active filter is effective only to harmonic current sources but not to harmonic voltage sources. On the other hand, the active filter connected in series with the system or `series active filter` is very effective in suppression of the harmonic voltage sources. General compensation characteristics of shunt active filters and series active filters are given analytically. The features, required operation conditions, and application considerations of both filters are described analytically and demonstrated experimentally.

  5. Shunt-capacitor-assisted synchronization of oscillations in intrinsic Josephson junctions stack.

    SciTech Connect

    Martin, I.; Halasz, G. B.; Bulaevskii, L. N.; Koshelev, A. E.; Materials Science Division; LANL

    2010-08-06

    We show that a shunt capacitor, by coupling each Josephson junction to all the other junctions, stabilizes synchronized oscillations in an intrinsic Josephson junction stack biased by a dc current. This synchronization mechanism is similar to the previously discussed radiative coupling between junctions, however, it is not defined by the geometry of the stack. It is particularly important in crystals with smaller numbers of junctions (where the radiation coupling is weak), and is comparable with the effect of strong super-radiation in crystals with many junctions. The shunt also helps to enter the phase-locked regime in the beginning of the oscillations, after switching on the bias current. Furthermore, it may be used to tune radiation power, which drops as the shunt capacitance increases.

  6. Electrospun polyurethane as an alternative ventricular catheter and in vitro model of shunt obstruction.

    PubMed

    Suresh, Supraja; Black, Richard A

    2015-02-01

    Intracranial pressure and volume vary considerably between hydrocephalic patients, and with age, health and haemodynamic status; if left untreated, intracranial pressure rises and the ventricular system expands to accommodate the excess cerebrospinal fluid, with significant morbidity and mortality. Cerebrospinal fluid shunts in use today have a high incidence of failure with shunt obstruction being the most serious. Conventional proximal shunt catheters are made from poly(dimethyl)siloxane, the walls of which are perforated with holes for the cerebrospinal fluid to pass through. The limited range of catheters, in terms of material selection and flow distribution, is responsible in large part for their poor performance. In this study, we present an alternative design of proximal catheter made of electrospun polyether urethane, and evaluate its performance in the presence of glial cells, which are responsible for shunt blockage. The viability and growth of cells on catheter materials such as poly(dimethyl)siloxane and polyurethane in the form of cast films, microfibrous mats and porous sponges were studied in the presence of proteins present in cerebrospinal fluid after 48 h and 96 h in culture. The numbers of viable cells on each substrate were comparable to untreated poly(dimethyl)siloxane, both in the presence and absence of serum proteins found in cerebrospinal fluid. A cell culture model of shunt obstruction was developed in which cells on electrospun polyether urethane catheters were subjected to flow during culture in vitro, and the degree of obstruction quantified in terms of hydraulic permeability after static and perfusion culture. The results indicate that a catheter made of electrospun polyether urethane would be able to maintain cerebrospinal fluid flow even with the presence of cells for the time period chosen for this study. These findings have implications for the design and deployment of microporous shunt catheter systems for the treatment of

  7. Electrospun polyurethane as an alternative ventricular catheter and in vitro model of shunt obstruction

    PubMed Central

    Suresh, Supraja

    2015-01-01

    Intracranial pressure and volume vary considerably between hydrocephalic patients, and with age, health and haemodynamic status; if left untreated, intracranial pressure rises and the ventricular system expands to accommodate the excess cerebrospinal fluid, with significant morbidity and mortality. Cerebrospinal fluid shunts in use today have a high incidence of failure with shunt obstruction being the most serious. Conventional proximal shunt catheters are made from poly(dimethyl)siloxane, the walls of which are perforated with holes for the cerebrospinal fluid to pass through. The limited range of catheters, in terms of material selection and flow distribution, is responsible in large part for their poor performance. In this study, we present an alternative design of proximal catheter made of electrospun polyether urethane, and evaluate its performance in the presence of glial cells, which are responsible for shunt blockage. The viability and growth of cells on catheter materials such as poly(dimethyl)siloxane and polyurethane in the form of cast films, microfibrous mats and porous sponges were studied in the presence of proteins present in cerebrospinal fluid after 48 h and 96 h in culture. The numbers of viable cells on each substrate were comparable to untreated poly(dimethyl)siloxane, both in the presence and absence of serum proteins found in cerebrospinal fluid. A cell culture model of shunt obstruction was developed in which cells on electrospun polyether urethane catheters were subjected to flow during culture in vitro, and the degree of obstruction quantified in terms of hydraulic permeability after static and perfusion culture. The results indicate that a catheter made of electrospun polyether urethane would be able to maintain cerebrospinal fluid flow even with the presence of cells for the time period chosen for this study. These findings have implications for the design and deployment of microporous shunt catheter systems for the treatment of

  8. Link between the CSF shunt and achievement in adults with spina bifida

    PubMed Central

    Hunt, G.; Oakeshott, P.; Kerry, S.

    1999-01-01

    OBJECTIVES—A few enterprising adults with shunt treated spina bifida live independently in the community, have a job in competitive employment, and drive to work in their own car. By contrast others with similar disability but lacking their motivation remain dependent on care and supervision. The aim of this study was to identify events in the history of their shunt which may have influenced their subsequent achievement.
METHODS—Between June 1963 and January 1971 117 babies born in East Anglia with open spina bifida had their backs closed regardless of the severity of their condition. When reviewed in 1997 every case was ascertained. Sixty had died and the 57 survivors had a mean age of 30. These were assigned to two groups: achievers and non-achievers, according to their attainments in independence, employment, and use of a car.
RESULTS—Of the 57 survivors nine had no shunt and eight of these were achievers. All were of normal intelligence (IQ⩾80) and only one was severely disabled. Of the 48 with shunts only 20 were achievers (OR 11.2, 95% confidence interval (95% CI) 1.3-96.8). Lack of achievement in these 48 was associated with revisions of the shunt, particularly when revisions were performed after the age of 2. Sixteen patients had never required a revision and 11 (69%) were achievers; 10 had had revisions only during infancy and five (50%) were achievers; 22 had had revisions after their second birthday and only four (18%) were achievers (p<0.001). Elective revisions were not performed in this cohort and in 75% of patients revisions had been preceded by clear symptoms of raised intracranial pressure.
CONCLUSION—Revisions of the shunt, particularly after the age of 2, are associated with poor long term achievement in adults with spina bifida.

 PMID:10519863

  9. Clinical Experience of Infantile Posthemorrhagic Hydrocephalus Treated with Ventriculo-Peritoneal Shunt

    PubMed Central

    Kim, Hae Min

    2015-01-01

    Objective Infantile posthemorrhagic hydrocephalus (IPHH) is the most common cause of infantile acquired hydrocephalus. We present and discuss our experience of treatment of six IPHH patients treated by a ventriculo-peritoneal (VP) shunt. Methods Six preterm infants treated by a VP shunt due to germinal matrix hemorrhage and hydrocephalus were included in our study. External ventricular drainage (EVD) was performed in patients with symptomatic ventricular dilatation, and a VP shunt was placed in the case of no improvement of the ventricular index despite several rounds of EVD. Radiographic findings and surgical outcomes were analyzed retrospectively. Results Four patients were male and two were female. Mean gestational age was 25 weeks and mean weight at birth was 868.3 g. One patient had a Papile grade II (16.7%) hemorrhage, three had a grade III (50%) hemorrhage, and two had a grade IV (33.3%) hemorrhage. EVD complications (one case of ventriculitis and one case of a ventricular abscess) occurred in two patients. VP shunt complications occurred in two patients (33.3%). Three cases had an isolated 4th ventricle; two of these cases had a VP shunt placed whereas the other case had a VP shunt placed in addition to aqueductoplasty using a neuroendoscope. At the last follow-up, three of the six patients had severe neurodevelopmental delay, two had mild neurodevelopmental delay, and one had normal development status. Conclusion In our study, although it is difficult to present the significant result for management of IPHH, we think that varied efforts are required to treat IPHH patients. PMID:27169074

  10. Evaluation of blood access dysfunction based on a wavelet transform analysis of shunt murmurs.

    PubMed

    Sato, Toshio; Tsuji, Kiichi; Kawashima, Norimichi; Agishi, Tetsuzo; Toma, Hiroshi

    2006-01-01

    We investigated shunt murmurs based on wavelet transform analysis as a new method for assessing vascular access function. In the present study, in patients with venous stenosis near an arteriovenous fistula (A-V fistula), a sensor was placed at different positions around the stenosis and shunt murmur signals obtained using a measurement system were subjected to time-frequency analysis based on wavelet transforms. The shunt murmurs obtained from the stenotic region closely represented some features of murmurs that are often referred to as "high-pitch" murmurs in the clinical setting. In contrast, shunt murmurs obtained about 5 cm downstream of the stenotic region closely represented some features of murmurs that are often referred to as "low-pitch" murmurs in the clinical setting. Furthermore, with the aim of extending the lifespan of arteriovenous grafts (A-V grafts) by detecting and treating stenotic lesions before the A-V graft becomes occluded, we evaluated the possibility of utilizing the present shunt murmur analysis for monitoring stenosis in such A-V grafts. When shunt murmurs from patients with A-V grafts were analyzed, the results suggested that the blood flow through the venous anastomosis of the graft was the most turbulent. This present method whereby blood flow in an A-V fistula is assessed based on the frequency distribution on a time-frequency plane by wavelet transform analysis is advantageous because findings are not markedly affected by sensor attachment. Furthermore, because the sensor is attached using an adhesive collar, measurements can be taken over a short period of time before each dialysis session. PMID:16807812

  11. Semi-active control of piezoelectric coating's underwater sound absorption by combining design of the shunt impedances

    NASA Astrophysics Data System (ADS)

    Sun, Yang; Li, Zhaohui; Huang, Aigen; Li, Qihu

    2015-10-01

    Piezoelectric shunt damping technology has been applied in the field of underwater sound absorption in recent years. In order to achieve broadband echo reduction, semi-active control of sound absorption of multi-layered piezoelectric coating by shunt damping is significant. In this paper, a practical method is proposed to control the underwater sound absorption coefficients of piezoelectric coating layers by combining design of the shunt impedance that allows certain sound absorption coefficients at setting frequencies. A one-dimensional electro-acoustic model of the piezoelectric coating and the backing is established based on the Mason equivalent circuit theory. First, the shunt impedance of the coating is derived under the constraint of sound absorption coefficient at one frequency. Then, taking the 1-3 piezoelectric composite coating as an example, the sound absorption properties of the coating shunted to the designed shunt impedance are investigated. Next, on the basis of that, an iterative method for two constrained frequencies and an optimizing algorithm for multiple constrained frequencies are provided for combining design of the shunt impedances. At last, an experimental sample with four piezoelectric material layers is manufactured, of which the sound absorption coefficients are measured in an impedance tube. The experimental results show good agreement with the finite element simulation results. It is proved that a serial R-L circuit can control the peak frequency, maximum and bandwidth of the sound absorption coefficient and the combining R-L circuits shunted to multiple layers can control the sound absorption coefficients at multiple frequencies.

  12. Method of removing the effects of electrical shorts and shunts created during the fabrication process of a solar cell

    DOEpatents

    Nostrand, Gerald E.; Hanak, Joseph J.

    1979-01-01

    A method of removing the effects of electrical shorts and shunts created during the fabrication process and improving the performance of a solar cell with a thick film cermet electrode opposite to the incident surface by applying a reverse bias voltage of sufficient magnitude to burn out the electrical shorts and shunts but less than the break down voltage of the solar cell.

  13. Implementation of FFT Algorithm using DSP TMS320F28335 for Shunt Active Power Filter

    NASA Astrophysics Data System (ADS)

    Patel, Pinkal Jashvantbhai; Patel, Rajesh M.; Patel, Vinod

    2016-07-01

    This work presents simulation, analysis and experimental verification of Fast Fourier Transform (FFT) algorithm for shunt active power filter based on three-level inverter. Different types of filters can be used for elimination of harmonics in the power system. In this work, FFT algorithm for reference current generation is discussed. FFT control algorithm is verified using PSIM simulation results with DLL block and C-code. Simulation results are compared with experimental results for FFT algorithm using DSP TMS320F28335 for shunt active power filter application.

  14. Unusual cause for ventriculoperitoneal shunt failure: carcinoma breast compressing distal catheter.

    PubMed

    Roka, Yam B; Gupta, R; Bajracharya, A

    2010-01-01

    Insertion of a ventriculoperitoneal (VP) shunt is one of the most common surgical procedures in any neurosurgery unit worldwide. Distal catheter obstruction outside the peritoneum is a rare cause of shunt failure. We report the first case of distal obstruction in a 70-year old female by carcinoma breast engulfing the catheter and causing kinking. Intraoperatively, the catheter was intratumoral with no flow of cerebrospinal fluid distally. She underwent relocation of a new catheter to the opposite side of the abdomen and modified mastectomy with resolution of the hydrocephalus. The postoperative course has been uneventful.

  15. Current diagnosis and management of post-transjugular intrahepatic portosystemic shunt refractory hepatic encephalopathy.

    PubMed

    Pereira, Keith; Carrion, Andres F; Martin, Paul; Vaheesan, Kirubahara; Salsamendi, Jason; Doshi, Mehul; Yrizarry, Jose M

    2015-12-01

    Transjugular intrahepatic portosystemic shunt has evolved into an important option for management of complications of portal hypertension. The use of polytetrafluoroethylene covered stents enhances shunt patency. Hepatic encephalopathy (HE) remains a significant problem after TIPS placement. The approach to management of patients with refractory hepatic encephalopathy typically requires collaboration between different specialties. Patient selection for TIPS requires careful evaluation of risk factors for HE. TIPS procedure-related technical factors like stent size, attention to portosystemic pressure gradient reduction and use of adjunctive variceal embolization maybe important. Conservative medical therapy in combination with endovascular therapies often results in resolution or substantial reduction of symptoms. Liver transplantation is, however, the ultimate treatment. PMID:26332169

  16. Percutaneous Mesocaval Shunt Creation in a Patient with Chronic Portal and Superior Mesenteric Vein Thrombosis.

    PubMed

    Bercu, Zachary L; Sheth, Sachin B; Noor, Amir; Lookstein, Robert A; Fischman, Aaron M; Nowakowski, F Scott; Kim, Edward; Patel, Rahul S

    2015-10-01

    The creation of a transjugular intrahepatic portosystemic shunt (TIPS) is a critical procedure for the treatment of recurrent variceal bleeding and refractory ascites in the setting of portal hypertension. Chronic portal vein thrombosis remains a relative contraindication to conventional TIPS and options are limited in this scenario. Presented is a novel technique for management of refractory ascites in a patient with hepatitis C cirrhosis and chronic portal and superior mesenteric vein thrombosis secondary to schistosomiasis and lupus anticoagulant utilizing fluoroscopically guided percutaneous mesocaval shunt creation.

  17. Stent graft exclusion of a pseudoaneurysm in a Blalock-Taussig shunt.

    PubMed

    Sanchez-Recalde, Angel; Garzón, Gonzalo; Oliver, José M

    2010-08-01

    This case is the first report of slow-growing pseudoaneurysm after vessel dissection secondary to two stents implantation into classic Blalock Taussig shunt in a patient with pulmonary atresia and ventricular septal defect. Pseudoaneurysm was successfully excluded by a percutaneous approach with self-expandable stent graft deployment from the aorta to the middle of the Blalock Taussig shunt. Nearly 3 years after the procedure, the classic BT is patent, and there were no restenosis or thrombosis in spite of the very long length of the stented segment.

  18. Pancreaticoportal Fistula and Disseminated Fat Necrosis After Revision of a Transjugular Intrahepatic Portosystemic Shunt

    SciTech Connect

    Klein, Seth J. Saad, Nael; Korenblat, Kevin; Darcy, Michael D.

    2013-04-15

    A 59-year old man with alcohol related cirrhosis and portal hypertension was referred for transjugular intrahepatic portosystemic shunt (TIPS) to treat his refractory ascites. Ten years later, two sequential TIPS revisions were performed for shunt stenosis and recurrent ascites. After these revisions, he returned with increased serum pancreatic enzyme levels and disseminated superficial fat necrosis; an iatrogenic pancreaticoportal vein fistula caused by disruption of the pancreatic duct was suspected. The bare area of the TIPS was subsequently lined with a covered stent-graft, and serum enzyme levels returned to baseline. In the interval follow-up period, the patient has clinically improved.

  19. Levoatriocardinal Vein: An Unusual Cause of Right-to-Left Shunting

    PubMed Central

    Shet, Nilima; Maldjian, Pierre

    2014-01-01

    We present a case demonstrating an anomalous vessel connecting the left brachiocephalic vein and the left superior pulmonary vein, found incidentally on computed tomography (CT) imaging. This pulmonary–systemic venous connection, known as a levoatriocardinal vein, is a rare anomaly. In previous descriptions, this vessel has typically been associated with left-to-right shunt. Here, we describe the magnetic resonance imaging (MRI) and CT findings in a case with right-to-left shunting through the anomalous vessel likely secondary to elevated right cardiac pressure. PMID:25558435

  20. [The radiographic appearances following correction of left-to-right shunts (author's transl)].

    PubMed

    Grünberg, G

    1978-12-01

    Amongst 22 patients with corrected left-to-right shunts, a diminution in heart size and reduction in central pulmonary arteries and pulmonary plethora was found in about half the patients. A good operative result can be expected, particularly in younger patients with less severe lesions, where the vessels had not been subjected to a high pressure for a long period. The failure of vessels to return to normal is assurmed to be due to changes in the vessel walls. Possible causes for persistent cardiomegaly are, in addition to persistent shunts, coronary artery disease, obesity, inadequate digitalisation and aortic and mitral insufficiency. PMID:153276

  1. Percutaneous Mesocaval Shunt Creation in a Patient with Chronic Portal and Superior Mesenteric Vein Thrombosis

    SciTech Connect

    Bercu, Zachary L. Sheth, Sachin B.; Noor, Amir; Lookstein, Robert A. Fischman, Aaron M. Nowakowski, F. Scott Kim, Edward Patel, Rahul S.

    2015-10-15

    The creation of a transjugular intrahepatic portosystemic shunt (TIPS) is a critical procedure for the treatment of recurrent variceal bleeding and refractory ascites in the setting of portal hypertension. Chronic portal vein thrombosis remains a relative contraindication to conventional TIPS and options are limited in this scenario. Presented is a novel technique for management of refractory ascites in a patient with hepatitis C cirrhosis and chronic portal and superior mesenteric vein thrombosis secondary to schistosomiasis and lupus anticoagulant utilizing fluoroscopically guided percutaneous mesocaval shunt creation.

  2. Neuroendoscopic surgery for ventriculitis and hydrocephalus after shunt infection and malfunction: Preliminary report of a new strategy

    PubMed Central

    Tabuchi, Sadaharu; Kadowaki, Mitsutoshi

    2015-01-01

    If not controlled in the early stage, ventriculitis is difficult to treat neurosurgically and can lead to serious sequelae, a long course of treatment, and hospitalization. We report two cases of ventriculitis and progressive hydrocephalus after shunt infection. Both were successfully treated by neuroendoscopic septostomy in combination with thorough intraventricular irrigation through a single burr hole followed by single shunt revision. Although surgical intervention has not been established as a first-choice treatment for ventriculitis, including early-stage ventriculitis, prompt neuroendoscopic surgery appears effective for the management of ventriculitis and hydrocephalus after shunt infection. The strategy described in this report might be useful to avoid recurrent shunt infections and malfunctions, simplify a shunt, and reduce the overall duration of hospitalization. PMID:25913583

  3. Unusual Ventriculoperitoneal (VP) Shunt Tube Extrusion through Anus in a Child with Dandy Walker Malformation: A Rare Case Report

    PubMed Central

    Gupta, Gulzar; Gupta, Mayank; Kaushal, Rakesh

    2015-01-01

    Aim of this paper is to report a case of extrusion of Ventriculo peritoneal shunt tube through anus in a one year female child ( k/c/o dandy walker malformation ) treated with placement of ventriculo peritoneal shunt for post operative hydrocephalus after excision of Subtorcular occipital meningocoel. The exact cause of such extrusion is not known. Unusual migration of distal catheter tip of VP shunt is a rare and bowel perforation is reported to occur between 0.1% and 0.7%. The possible factors responsible for this complication are thin bowel wall in children, sharp and stiff end of the VP shunt, use of trocar by some surgeons, chronic irritation by the shunt, previous surgery, infection and silicone allergy. In view of the potential for meningitis prompt and aggressive management is essential to avoid morbidity and mortality. PMID:25738035

  4. Severance of a ventriculoperitoneal shunt catheter implanted between the cerebral ventricle and peritoneal cavity, resulting in protrusion from the anus.

    PubMed

    Hayama, Tamuro; Ishihara, Soichiro; Yamazaki, Norihito; Akahane, Takuya; Shimada, Ryu; Horiuchi, Atsushi; Shibuya, Hajime; Yamada, Hideki; Nozawa, Keijiro; Matsuda, Keiji; Watanabe, Toshiaki

    2011-01-01

    One rare complication of a ventriculoperitoneal (VP) shunt is perforation of the gastrointestinal tract by the catheter. We report a case in which the catheter severed spontaneously inside the peritoneal cavity, creating a communication between the intestinal tract and the peritoneal cavity. The patient was a 41-year-old man who presented with a VP shunt catheter protruding from the anus. Computed tomography showed that the VP shunt catheter, which had been put in place 25 years earlier, had severed spontaneously. The distal end had then perforated and entered the intestinal tract. The patient was hospitalized and emergency surgery was performed to repair the intestinal tract perforation caused by the end of the VP shunt catheter. Laparotomy revealed that the catheter had perforated the sigmoid colon. The VP shunt catheter was removed, and the perforation in the intestinal tract was closed by suturing. The patient was discharged on postoperative day 20.

  5. Neuroendoscopic surgery for ventriculitis and hydrocephalus after shunt infection and malfunction: Preliminary report of a new strategy.

    PubMed

    Tabuchi, Sadaharu; Kadowaki, Mitsutoshi

    2015-05-01

    If not controlled in the early stage, ventriculitis is difficult to treat neurosurgically and can lead to serious sequelae, a long course of treatment, and hospitalization. We report two cases of ventriculitis and progressive hydrocephalus after shunt infection. Both were successfully treated by neuroendoscopic septostomy in combination with thorough intraventricular irrigation through a single burr hole followed by single shunt revision. Although surgical intervention has not been established as a first-choice treatment for ventriculitis, including early-stage ventriculitis, prompt neuroendoscopic surgery appears effective for the management of ventriculitis and hydrocephalus after shunt infection. The strategy described in this report might be useful to avoid recurrent shunt infections and malfunctions, simplify a shunt, and reduce the overall duration of hospitalization. PMID:25913583

  6. Performance of organics and nitrogen removal in subsurface wastewater infiltration systems by intermittent aeration and shunt distributing wastewater.

    PubMed

    Pan, Jing; Yuan, Fang; Yu, Long; Huang, Linli; Fei, Hexin; Cheng, Fan; Zhang, Qi

    2016-07-01

    Organics and nitrogen removal in four subsurface wastewater infiltration systems (SWISs), named SWIS A (without intermittent aeration and shunt distributing wastewater), SWIS B (with intermittent aeration), SWIS C (with shunt distributing wastewater) and SWIS D (with intermittent aeration and shunt distributing wastewater) was investigated. High average removal rates of 92.3% for COD, 90.2% for NH4-N and 88.1% for TN were achieved simultaneously in SWIS D compared with SWIS A, B and C. The excellent TN removal of SWIS D was due to intermittent aeration provided sufficient oxygen for nitrification in upper matrix and the favorable anoxic or anaerobic environment for denitrification in subsequent matrix, and moreover, shunt distributing wastewater provided sufficient carbon source for denitrification process. The results indicated that intermittent artificial aeration combined with shunt distributing wastewater could achieve high organics and nitrogen removal in SWISs.

  7. Increased risk of distal ventriculoperitoneal shunt obstruction associated with slit valves or distal slits in the peritoneal catheter.

    PubMed

    Cozzens, J W; Chandler, J P

    1997-11-01

    The authors describe a relationship between the presence of distal shunt catheter side-wall slits and distal catheter obstruction in a single-surgeon series of ventriculoperitoneal (VP) shunt revisions. Between 1985 and 1996, 168 operations for VP shunt revision were performed by the senior author (J.W.C.) in 71 patients. Indications for shunt revision included obstruction in 140 operations; overdrainage or underdrainage requiring a change of valve in 17 operations; inadequate length of distal shunt tubing resulting in the distal end no longer reaching the peritoneum in five operations; the ventricular catheter in the wrong ventricle or space, requiring repositioning in five operations; and a disconnected or broken shunt in one operation. Of the 140 instances of shunt obstruction, the blockage occurred at the ventricular end in 108 instances (77.1%), the peritoneal end in 17 (12.1%), the ventricular and the peritoneal end in 14 (10%), and in the valve mechanism (not including distal slit valves) in one (0.8%). Thus, the peritoneal end was obstructed in 31 (22.1%) of 140 cases of shunt malfunction. In every case in which the peritoneal end was obstructed, some form of distal slit was found: either a distal slit valve in an otherwise closed catheter or slits in the side of an open catheter. No instances were found of distal peritoneal catheter obstruction when the peritoneal catheter was a simple open-ended tube with no accompanying side slits (0 of 55). It is concluded that side slits in the distal peritoneal catheters of VP shunts are associated with a greater incidence of distal shunt obstruction.

  8. Co-Localization of GABA Shunt Enzymes for the Efficient Production of Gamma-Aminobutyric Acid via GABA Shunt Pathway in Escherichia coli.

    PubMed

    Pham, Van Dung; Somasundaram, Sivachandiran; Park, Si Jae; Lee, Seung Hwan; Hong, Soon Ho

    2016-04-28

    Gamma-aminobutyric acid (GABA) is a non-protein amino acid, which is an important inhibitor of neurotransmission in the human brain. GABA is also used as the precursor of biopolymer Nylon-4 production. In this study, the carbon flux from the tricarboxylic acid cycle was directed to the GABA shunt pathway for the production of GABA from glucose. The GABA shunt enzymes succinate-semialdehyde dehydrogenase (GabD) and GABA aminotransferase (GabT) were co-localized along with the GABA transporter (GadC) by using a synthetic scaffold complex. The co-localized enzyme scaffold complex produced 0.71 g/l of GABA from 10 g/l of glucose. Inactivation of competing metabolic pathways in mutant E. coli strains XBM1 and XBM6 increased GABA production 13% to reach 0.80 g/l GABA by the enzymes co-localized and expressed in the mutant strains. The recombinant E. coli system developed in this study demonstrated the possibility of the pathway of the GABA shunt as a novel GABA production pathway.

  9. [Functional respiratory disorders in children with left-to-right shunt].

    PubMed

    Girardet, J P; Gaultier, C; Boulé, M; Magnier, S; Duclos, M; Fontaine, J L

    1981-12-01

    The respiratory function of 19 children aged from 2 months to 9 years old with a cardiac lesion giving a left-to-right shunt was studied and analysed with respect to the hemodynamic disturbance. Respiratory function tests (RFTs) included measurement of functional residual capacity (FRC), the partial pressure in oxygen (Pa 02) on arterialised blood taken from the ear lobe, dynamic pulmonary compliance (CI dyn.) and total pulmonary resistance (RI). FRC and RI were not significantly modified. On the other hand, CI. dyn. was low (-31.2 +/- 22.9%, p less than 0,001) as were the CI. dyn. CFR ratio (-25.5 +/- 20.9%, p less than 0.001) and the Pa 02 (-7.6 +/- 12.7% p less than 0.02). There was a significant correlation between the reduction of CI. dyn. and mean pulmonary arterial pressure (PAP) and the increase in the pulmonary blood flow. In addition, a significant correlation was also found between the reduction in Pa 02 and the PAP and increase in pulmonary blood flow. These results show that cardiac lesions with left-to-right shunts give rise to diffuse changes in respiratory function and are discussed in the light of the abnormalities in pulmonary development previously described in pulmonary biopsy of patients with left-to-right shunts. The value of RFTs in the surveillance of patients with left-to-right shunts is underlined.

  10. Laser restoration of flow in occluded ventricular shunts for pediatric neurosurgery

    NASA Astrophysics Data System (ADS)

    Christens-Barry, William A.; Guarnieri, Michael; Carson, Benjamin S.

    1998-01-01

    We have investigated the use of short pulses of infrared ((lambda) equals 2.09 micrometers ) light from a Ho:YAG laser to photofragment occlusions and restore flow in ventricular shunts, which provide the sole means of maintaining proper intracranial pressure in hydrocephalus patients. These experiments employed model tissues, a polymeric model compound, and patient explants in order to determine appropriate pulse energies and delivery rates for removal of occlusions material. Laser energy doses and rates of occlusion removal were established for these materials. Laser energy doses that do not damage the shunt device or surrounding tissue were identified. Optical fibers (25 ga. or smaller) can be introduced through the dome of current shunt devices and threaded to the occlusion site. Clinical application will require the continued development of an introducer tool for the transcutaneous insertion of the optical fiber into the shunt device and irrigation techniques for removing the occlusion detritus generated by photofragmentation treatment. Using this approach, a minimally invasive and benign procedure for in situ restoration of flow in occluded neurological implant devices becomes possible.

  11. Bladder calculus formation on the tip of a migrated disused ventriculoperitoneal shunt.

    PubMed

    Butler, Laura; Keys, Charles; Lam, Jimmy P H

    2013-05-01

    Bladder stones in children are rare. They generally occur in children with one or more predisposing risk factors to stone formation. In this unique case report we discuss the formation and successful endoscopic treatment of a large stone in a neuropathic bladder on the tip of a migrated VP shunt.

  12. Racial and socioeconomic disparities in outcomes following pediatric cerebrospinal fluid shunt procedures.

    PubMed

    Attenello, Frank J; Ng, Alvin; Wen, Timothy; Cen, Steven Y; Sanossian, Nerses; Amar, Arun P; Zada, Gabriel; Krieger, Mark D; McComb, J Gordon; Mack, William J

    2015-06-01

    OBJECT Racial and socioeconomic disparities within the US health care system are a growing concern. Despite extensive research and efforts to narrow such disparities, minorities and economically disadvantaged patients continue to exhibit inferior health care outcomes. Disparities in the delivery of pediatric neurosurgical care are understudied. Authors of this study examine the impact of race and socioeconomic status on outcomes following pediatric CSF shunting procedures. METHODS Discharge information from the 2000, 2003, 2006, and 2009 Kids' Inpatient Database for individuals (age < 21 years) with a diagnosis of hydrocephalus who had undergone CSF shunting procedures was abstracted for analysis. Multivariate logistic regression analyses, adjusting for patient and hospital factors and annual CSF shunt procedure volume, were performed to evaluate the effects of race and payer status on the likelihood of inpatient mortality and nonroutine hospital discharge (that is, not to home). RESULTS African American patients (p < 0.05) had an increased likelihood of inpatient death and nonroutine discharge compared with white patients. Furthermore, Medicaid patients had a significantly higher likelihood of nonroutine discharge (p < 0.05) as compared with privately insured patients. CONCLUSIONS Findings in this study, which utilized US population-level data, suggest the presence of racial and socioeconomic status outcome disparities following pediatric CSF shunting procedures. Further studies on health disparities in this population are warranted.

  13. Transjugular Intrahepatic Portosystemic Shunt for the Treatment of Portal Hypertension in Noncirrhotic Patients with Portal Cavernoma

    PubMed Central

    Luo, Xuefeng; Zhou, Biao; Yao, Denghua; Ma, Huaiyuan; Jiang, Mingshan; Zhang, Hailong; Li, Xiao

    2014-01-01

    Background. The purpose of this study was to evaluate the safety and efficacy of transjugular intrahepatic portosystemic shunt (TIPS) placement in the management of portal hypertension in noncirrhotic patients with portal cavernoma. Methods. We conducted a single institution retrospective analysis of 15 noncirrhotic patients with portal cavernoma treated with TIPS placement. 15 patients (4 women and 11 men) were evaluated via the technical success of TIPS placement, procedural complications, and follow-up shunt patency. Results. TIPS placement was technically successful in 11 out of 15 patients (73.3%). Procedure-related complications were limited to a single instance of hepatic encephalopathy in one patient. In patients with successful shunt placement, the portal pressure gradient decreased from 25.8 ± 5.7 to 9.5 ± 4.2 mmHg (P < 0.001). TIPS dysfunction occurred in two patients during a median follow-up time of 45.2 months. Revision was not performed in one patient due to inadequate inflow. The other patient died of massive gastrointestinal bleeding in a local hospital. The remaining nine patients maintained functioning shunts through their last evaluation. Conclusions. TIPS is a safe and effective therapeutic treatment for noncirrhotic patients with symptomatic portal hypertension secondary to portal cavernoma. PMID:24868203

  14. Role of kinetic inductance in transport properties of shunted superconducting nanowires.

    PubMed

    Lin, Shi-Zeng; Roy, Dibyendu

    2013-08-14

    Recently, transport measurements have been carried out in resistively shunted long superconducting nanowires (Brenner et al 2012 Phys. Rev. B 85 224507). The measured voltage-current (V-I) characteristics were explained by the appearance of the phase slip centers in the shunted wire, and the whole wire was modeled as a single Josephson junction. The kinetic inductance of the long nanowires used in experiments is generally large. Here we argue that the shunted superconducting nanowire acts as a Josephson junction in series with an inductor. The inductance depends on the length and the cross section of the wire. The inclusion of inductance in our analysis modifies the V-I curves, and increases the rate of switching from the superconducting state to the resistive state. The quantitative differences can be quite large in some practical parameter sets, and might be important to properly understand the experimental results. Our proposed model can be verified experimentally by studying the shunted superconducting nanowires of different lengths and cross sections.

  15. Negative capacitance shunt damping system with optimized characteristics for use with piezoelectric transducers

    NASA Astrophysics Data System (ADS)

    Pohl, Martin

    2014-03-01

    For ecologic sustainability and decreasing reserves of fossile energy sources, fuel efficiency is a major concern especially for passenger aircraft. Therefore, lightweight structures made from carbon fiber plastics offer great potential. But when used for panel-like structures, they have the disadvantage of lower damping and coincidence frequencies compared to conventional differential metal constructions. Both aspects lead to an increased vibration level and by this a higher noise radiation. Because of this, special noise and vibration treatment is needed to ensure passenger cabin comfort. Besides passive damping and active structural acoustic control (ASAC), piezoelectric shunt damping is investigated. Due to its broadband performance, the negative capacitance shunt can be used for multimode systems with varying eigenfrequencies. These shunts are usually built with operational amplifiers and passive components as resistors and capacitors. This setup is sufficient for laboratory tests at low excitation levels. In fact, it is not capable of accessing the full voltage amplitude of common piezoelectric transducers, because most operational amplifiers only deliver +/-15V maximum output voltage. Therefore an improved setup is presented in this paper, which addresses the specific voltage requirements of a common piezoelectric transducer to achieve best performance. It comprises a tailored power source and an appropriate concept for the negative capacitance shunt hardware. This new hardware only uses standard operational amplifiers together with a high voltage power amplifier to cover the whole operating range of a piezoelectric transducer. A demonstrator board is developed and experimentally investigated at a test structure. Finally, the results are compared to a conventional setup.

  16. Manipulating waves by distilling frequencies: a tunable shunt-enabled rainbow trap

    NASA Astrophysics Data System (ADS)

    Cardella, Davide; Celli, Paolo; Gonella, Stefano

    2016-08-01

    In this work, we propose and test a strategy for tunable, broadband wave attenuation in electromechanical waveguides with shunted piezoelectric inclusions. Our strategy is built upon the vast pre-existing literature on vibration attenuation and bandgap generation in structures featuring periodic arrays of piezo patches, but distinguishes itself for several key features. First, we demystify the idea that periodicity is a requirement for wave attenuation and bandgap formation. We further embrace the idea of ‘organized disorder’ by tuning the circuits as to resonate at distinct neighboring frequencies. In doing so, we create a tunable ‘rainbow trap’ (Tsakmakidis et al 2007 Nature 450 397–401) capable of attenuating waves with broadband characteristics, by distilling (sequentially) seven frequencies from a traveling wavepacket. Finally, we devote considerable attention to the implications in terms of packet distortion of the spectral manipulation introduced by shunting. This work is also meant to serve as a didactic tool for those approaching the field of shunted piezoelectrics, and attempts to provide a different perspective, with abundant details, on how to successfully design an experimental setup involving resistive-inductive shunts.

  17. Model for Calculating Electrolytic Shunt Path Losses in Large Electrochemical Energy Conversion Systems

    NASA Technical Reports Server (NTRS)

    Prokopius, P. R.

    1976-01-01

    Generalized analysis and solution techniques were developed to evaluate the shunt power losses in electrochemical systems designed with a common or circulating electrolyte supply. Sample data are presented for a hypothetical bulk energy storage redox system, and the general applicability of the analysis technique is discussed.

  18. Manipulating waves by distilling frequencies: a tunable shunt-enabled rainbow trap

    NASA Astrophysics Data System (ADS)

    Cardella, Davide; Celli, Paolo; Gonella, Stefano

    2016-08-01

    In this work, we propose and test a strategy for tunable, broadband wave attenuation in electromechanical waveguides with shunted piezoelectric inclusions. Our strategy is built upon the vast pre-existing literature on vibration attenuation and bandgap generation in structures featuring periodic arrays of piezo patches, but distinguishes itself for several key features. First, we demystify the idea that periodicity is a requirement for wave attenuation and bandgap formation. We further embrace the idea of ‘organized disorder’ by tuning the circuits as to resonate at distinct neighboring frequencies. In doing so, we create a tunable ‘rainbow trap’ (Tsakmakidis et al 2007 Nature 450 397-401) capable of attenuating waves with broadband characteristics, by distilling (sequentially) seven frequencies from a traveling wavepacket. Finally, we devote considerable attention to the implications in terms of packet distortion of the spectral manipulation introduced by shunting. This work is also meant to serve as a didactic tool for those approaching the field of shunted piezoelectrics, and attempts to provide a different perspective, with abundant details, on how to successfully design an experimental setup involving resistive-inductive shunts.

  19. Tube shunt coverage with gamma-irradiated cornea allograft (VisionGraft)

    PubMed Central

    Ekici, Feyzahan; Moster, Marlene R; Cvintal, Victor; Hu, Wanda D; Waisbourd, Michael

    2015-01-01

    Purpose To investigate the clinical outcomes of tube shunt coverage using sterile gamma-irradiated cornea allograft. Patients and methods The Wills Eye Hospital Glaucoma Research Center retrospectively reviewed the medical records of 165 patients who underwent glaucoma tube shunt procedures using sterile gamma-irradiated cornea allograft (VisionGraft) between December 2012 and November 2013. Demographic characteristics, type of tube shunt, and position were noted. Complications were recorded at 1 day; 1 week; 1, 3, 6, and 12 months; and on the final postoperative visit. Results One hundred and sixty-nine eyes of 165 patients were included. The mean follow-up time was 4.8±3.5 (ranging from 1 to 16) months. There was no evidence of immunological reaction, infection, or exposure in 166 eyes (98.2%). Three eyes (1.8%) experienced graft or tube exposure within the first 3 postoperative months. Two of the cases had underlying diseases: bullous pemphigoid and chronic allergic conjunctivitis. Conclusion Coverage of tube shunts using gamma-irradiated cornea allograft had a low exposure rate and was well tolerated. The graft can be stored long term at room temperature and has an excellent postoperative cosmetic appearance. PMID:25995612

  20. Shunt-Enhanced, Lead-Driven Bifurcation of Epilayer GaAs based EEC Sensor Responsivity

    NASA Astrophysics Data System (ADS)

    Solin, Stuart; Werner, Fletcher

    2015-03-01

    The results reported here explore the geometric optimization of room-temperature EEC sensor responsivity to applied bias by exploring contact geometry and location. The EEC sensor structure resembles that of a MESFET, but the measurement technique and operation distinguish the EEC sensor significantly; the EEC sensor employs a four-point resistance measurement as opposed to a two-point source-drain measurement and is operated under both forward and reverse bias. Under direct forward bias, the sensor distinguishes itself from a traditional FET by allowing current to be injected from the gate, referred to as a shunt, into the active layer. We show that the observed bifurcation in EEC sensor response to direct reverse bias depends critically on measurement lead location. A dramatic enhancement in responsivity is achieved via a modification of the shunt geometry. A maximum percent change of 130,856% of the four-point resistance was achieved under a direct reverse bias of -1V using an enhanced shunt design, a 325 fold increase over the conventional EEC square shunt design. This result was accompanied by an observed bifurcation in sensor response, driven by a rotation of the four-point measurement leads. S. A. S is a co-founder of and has a financial interest in PixelEXX, a start-up company whose mission is to market imaging arrays.

  1. Sternotomy approach for modified Blalock-Taussig shunt: is it a safe option?

    PubMed

    Kandakure, Pramod Reddy; Dharmapuram, Anil Kumar; Ramadoss, Nagarajan; Babu, Vivek; Rao, Ivatury Mrityunjaya; Murthy, Kona Samba

    2010-08-01

    Central aorta-pulmonary artery shunts have fallen into disfavor because of shunt thrombosis and congestive heart failure, and a modified Blalock-Taussig shunt via thoracotomy can lead to pulmonary artery hypoplasia and distortion. We reviewed the outcomes of a modified Blalock-Taussig shunt by a sternotomy approach in 20 infants from July 2007 to October 2009. Their mean age was 5.79 months, and median weight was 5.4 kg. A 4-mm graft was placed in 11 patients, a 5-mm graft in 8, and a 3.5-mm graft in 1. There was no incidence of sepsis, seroma, or phrenic nerve palsy. There was one hospital death. The mean hospital stay was 10.4 +/- 4.3 days (range, 8-15 days). The mean oxygen saturation at discharge was 89% (range, 81%-93%). The sternotomy approach is technically easier to perform, cosmetically preferable, and probably hemodynamically superior. Correction of branch pulmonary stenosis is easily incorporated into this procedure. The theoretical disadvantage of this method is a potential technical difficulty with sternal reentry for subsequent procedures. PMID:20719789

  2. Effects of Ground Equalization on the Electrical Performance of Asymmetric CPW Shunt Stubs

    NASA Technical Reports Server (NTRS)

    Dib, Nihad; Gupta, Minoo; Ponchak, George; Katehi, Linda

    1993-01-01

    A hybrid technique is used to study the effects of ground equalization on the electrical performance of CPW shunt stubs. Extensive experiments have been performed and the results are in good agreement with theoretical data. The advantages of using air-bridges in CPW circuits as opposed to bond-wires are also discussed.

  3. Photoacoustic microscopy of arteriovenous shunts and blood diffusion in early-stage tumors

    NASA Astrophysics Data System (ADS)

    Yeh, Chenghung; Liang, Jinyang; Zhou, Yong; Hu, Song; Sohn, Rebecca E.; Arbeit, Jeffrey M.; Wang, Lihong V.

    2016-02-01

    Angiogenesis in a tumor region creates arteriovenous (AV) shunts that cause an abnormal venous blood oxygen saturation (sO2) distribution. Here, we applied optical-resolution photoacoustic microscopy to study the AV shunting in vivo. First, we built a phantom to image sO2 distribution in a vessel containing converged flows from two upstream blood vessels with different sO2 values. The phantom experiment showed that the blood from the two upstream vessels maintained a clear sO2 boundary for hundreds of seconds, which is consistent with our theoretical analysis using a diffusion model. Next, we xenotransplanted O-786 tumor cells in mouse ears and observed abnormal sO2 distribution in the downstream vein from the AV shunts in vivo. Finally, we identified the tumor location by tracing the sO2 distribution. Our study suggests that abnormal sO2 distribution induced by the AV shunts in the vessel network may be used as a new functional benchmark for early tumor detection.

  4. An adaptive metamaterial beam with hybrid shunting circuits for extremely broadband control of flexural waves

    NASA Astrophysics Data System (ADS)

    Chen, Y. Y.; Hu, G. K.; Huang, G. L.

    2016-10-01

    A great deal of research has been devoted to controlling the dynamic behaviors of phononic crystals and metamaterials by directly tuning the frequency regions and/or widths of their inherent band gaps. Here, we report a new class of adaptive metamaterial beams with hybrid shunting circuits to realize super broadband Lamb-wave band gaps at an extreme subwavelength scale. The proposed metamaterial is made of a homogeneous host beam on which tunable local resonators consisting of hybrid shunted piezoelectric stacks with proof masses are attached. The hybrid shunting circuits are composed of negative-capacitance and negative-inductance elements connected in series or in parallel in order to tune the desired frequency-dependent stiffness. It is shown theoretically and numerically that by properly modifying the shunting impedance, the adaptive mechanical mechanism within the tunable resonator can produce high-pass and low-pass wave filtering capabilities for the zeroth-order anti-symmetric Lamb-wave modes. These unique behaviors are due to the hybrid effects from the negative-capacitance and negative-inductance circuit elements. Such a system opens up important perspectives for the development of adaptive vibration or wave-attenuation devices for broadband frequency applications.

  5. Low-dose acetylsalicylic acid and bleeding risks with ventriculoperitoneal shunt placement.

    PubMed

    Kamenova, Maria; Croci, Davide; Guzman, Raphael; Mariani, Luigi; Soleman, Jehuda

    2016-09-01

    OBJECTIVE Ventriculoperitoneal (VP) shunt placement is a common procedure for the treatment of hydrocephalus following diverse neurosurgical conditions. Most of the patients present with other comorbidities and receive antiplatelet therapy, usually acetylsalicylic acid (ASA). Despite its clinical relevance, the perioperative management of these patients has not been sufficiently investigated. The aim of this study was to compare the peri- and postoperative bleeding complication rates associated with ASA intake in patients undergoing VP shunt placement. METHODS Of 172 consecutive patients undergoing VP shunt placement between June 2009 and December 2015, 40 (23.3%) patients were receiving low-dose ASA treatment. The primary outcome measure was bleeding events in ASA users versus nonusers, whereas secondary outcome measures were postoperative cardiovascular events, hematological findings, morbidity, and mortality. A subgroup analysis was conducted in patients who discontinued ASA treatment for < 7 days (n = 4, ASA Group 1) and for ≥ 7 days (n = 36, ASA Group 2). RESULTS No statistically significant difference for bleeding events was observed between ASA users and nonusers (p = 0.30). Cardiovascular complications, surgical morbidity, and mortality did not differ significantly between the groups either. Moreover, there was no association between ASA discontinuation regimens (< 7 days and ≥ 7 days) and hemorrhagic events. CONCLUSIONS Given the lack of guidelines regarding perioperative management of neurosurgical patients with antiplatelet therapy, these findings elucidate one issue, showing comparable bleeding rates in ASA users and nonusers undergoing VP shunt placement. PMID:27581316

  6. An improved reservoir for the flushing test to diagnose shunt insufficiency.

    PubMed

    Schlosser, Hans-Georg; Crawack, Hans-Joachim; Miethke, Christoph; Knitter, Thoralf; Zeiner, Andreas; Sprung, Christian

    2016-09-01

    OBJECTIVE Reservoirs integrated into hydrocephalus shunts are commonly used for the removal of CSF and for intra-ventricular pressure measurement. Pumping with the reservoir to diagnose shunt sufficiency is still a matter of controversy. The authors describe an improved flushing device and its characteristic features in vitro and in vivo. METHODS The flushing reservoir is constructed with a sapphire ball in a cage as a nonresistance valve to also enable the detection of distal occlusions. The most important reservoir parameters were investigated in vitro, simulating total and partial proximal and distal shunt occlusions. Then the expected advantages were assessed in vivo by evaluating the pump test data of 360 implanted reservoirs. The results were compared with those found in the literature. RESULTS The optimization of the technical parameters of the device, such as the high stroke volume in combination with moderate suction force, are obvious advantages compared with other flushing devices. Total occlusion of the ventricular catheter and the valve could be assessed with high certainty. The detection of a total obstruction of the peritoneal catheter or any partial obstruction is also possible, depending on its exact grade and location. CONCLUSIONS Shunt obstructions can be assessed using the pumping test. The reservoir construction presented here provides a clear enhancement of that diagnostic test. PMID:27581310

  7. Computer simulation of magnetization-controlled shunt reactors for calculating electromagnetic transients in power systems

    SciTech Connect

    Karpov, A. S.

    2013-01-15

    A computer procedure for simulating magnetization-controlled dc shunt reactors is described, which enables the electromagnetic transients in electric power systems to be calculated. It is shown that, by taking technically simple measures in the control system, one can obtain high-speed reactors sufficient for many purposes, and dispense with the use of high-power devices for compensating higher harmonic components.

  8. A baboon flow-regulated shunt for the study of small caliber vascular grafts

    SciTech Connect

    Mackey, W.C.; Keough, E.M.; Connolly, R.J.; McCullough, J.L.; Ramberg-Laskaris, K.; O'Donnell, T.F. Jr.; Foxall, T.; Callow, A.D.

    1984-08-01

    Synthetic vascular grafts often occlude when used in low-flow high-resistance reconstructions. In order to study the pathophysiology of graft failure a flow-regulated ex vivo shunt was designed for insertion into the baboon femoral artery and vein. Synthetic graft materials (4 mm i.d.) can be placed into the shunt circuit and studied at known rates of flow for uptake of 111In-labeled platelets. Segments of the grafts can be removed from the shunt circuit at specified time intervals for morphologic study with scanning electron microscopy (SEM). In this paper the shunt model is described in detail and early experiments with it are reported. Labeled platelet uptake and SEM studies suggest that flow rate and graft composition influence the deposition of platelets and other blood components on graft surfaces. At high-flow knitted Dacron attracts large numbers of platelets, and becomes covered with a nearly confluent platelet-protein carpet within 1 hr. At low flow platelet uptake and development of the platelet-protein carpet is slower. Polytetrafluoroethylene (PTFE) attracts few platelets at high-flow rates, but at lower-flow rates begins to develop a platelet-protein carpet similar to that seen on knitted Dacron. Flow-related factors influencing platelet deposition are discussed and further experiments to be carried out with this model are described.

  9. Yellow nails, lymphedema and pleural effusion. Treatment of chronic pleural effusion with pleuroperitoneal shunting.

    PubMed

    Brofman, J D; Hall, J B; Scott, W; Little, A G

    1990-03-01

    Pleural effusion secondary to lymphedema may be chronic, symptomatic and refractory to treatment, occasionally requiring invasive and painful procedures such as chemical pleurodesis, open pleural abrasion or pleurectomy to achieve control of the effusion and gain symptomatic relief. We report a patient with yellow nail syndrome and chronic pleural effusion successfully treated with pleuroperitoneal shunting.

  10. Improved negative capacitance shunt damping with the use of acoustic black holes

    NASA Astrophysics Data System (ADS)

    Beck, Benjamin S.; Cunefare, Kenneth A.

    2014-03-01

    Negative capacitance shunt damping is an effective broadband method for attenuating flexural vibration. However, proper selection of the location of the piezoelectric patches on a structure to maximize reduction has been an ongoing question in the field. Acoustic black holes are a recently developed concept to reduce vibrations on thin vibrating structures. By engineering the geometric or material properties of these thin structures, it is possible to minimize the reflected wave by gradually reducing the wave speed. However, the flexural wave speed cannot be reduced to zero on a realized structure. Therefore, when acoustic black holes are implemented, some of the incident wave energy is reflected because the wave speed must be truncated. Similarly due to the reduction in wave speed, the transverse velocity significantly increases within the acoustic black hole. It is therefore possible to add piezoelectric transducers to acoustic black hole regions on a structure to utilize negative capacitance shunt damping to address both of these issues. Consequently, the transducers are placed in the locations where the greatest control can be made and the reflected waves can be attenuated. The combination of negative capacitance shunt damping with acoustic black holes shows increased suppression of vibration over shunt damping alone.

  11. A Multi-Mode Blade Damping Control using Shunted Piezoelectric Transducers with Active Feedback Structure

    NASA Technical Reports Server (NTRS)

    Choi, Benjamin; Morrison, Carlos; Min, James

    2009-01-01

    The Structural Dynamics and. Mechanics branch (RXS) is developing smart adaptive structures to improve fan blade damping at resonances using piezoelectric (PE) transducers. In this presentation, only one shunted PE transducer was used to demonstrate active control of multi-mode blade resonance damping on a titanium alloy (Ti-6A1-4V) flat plate model, regardless of bending, torsion, and 2-stripe modes. This work would have a significant impact on the conventional passive shunt damping world because the standard feedback control design tools can now be used to design and implement electric shunt for vibration control. In other words, the passive shunt circuit components using massive inductors and. resistors for multi-mode resonance control can be replaced with digital codes. Furthermore, this active approach with multi patches can simultaneously control several modes in the engine operating range. Dr. Benjamin Choi presented the analytical and experimental results from this work at the Propulsion-Safety and. Affordable Readiness (P-SAR) Conference in March, 2009.

  12. Anal extrusion of migrated ventriculo-peritoneal shunt catheter: An unusual complication and review of literature

    PubMed Central

    Sarkari, Avijit; Borkar, Sachin A.; Mahapatra, A. K.

    2016-01-01

    Authors present an unusual case of anal extrusion of peritoneal end of ventriculo-peritoneal shunt in a 2-year-old male child. Pertinent literature is reviewed regarding this rare complication of a very commonly performed neurosurgical procedure. PMID:27695576

  13. Transjugular Intrahepatic Portosystemic Shunt Placement in Patients with Cirrhosis and Concomitant Portal Vein Thrombosis

    SciTech Connect

    Ha, Thuong G. Van Hodge, Justin; Funaki, Brian; Lorenz, Jonathan; Rosenblum, Jordan; Straus, Christopher; Leef, Jeff

    2006-10-15

    Purpose. To determine the safety and efficacy of transjugular intrahepatic portosystemic shunt (TIPS) creation in patients with liver cirrhosis complicated by thrombosed portal vein. Methods. This study reviewed 15 cases of TIPS creation in 15 cirrhotic patients with portal vein thrombosis at our institution over an 8-year period. There were 2 women and 13 men with a mean age of 53 years. Indications were refractory ascites, variceal hemorrhage, and refractory pleural effusion. Clinical follow-up was performed in all patients. Results. The technical success rate was 75% (3/4) in patients with chronic portal vein thrombosis associated with cavernomatous transformation and 91% (10/11) in patients with acute thrombosis or partial thrombosis, giving an overall success rate of 87%. Complications included postprocedural encephalopathy and localized hematoma at the access site. In patients with successful shunt placement, the total follow-up time was 223 months. The 30-day mortality rate was 13%. Two patients underwent liver transplantation at 35 days and 7 months, respectively, after TIPS insertion. One patient had an occluded shunt at 4 months with an unsuccessful revision. The remaining patients had functioning shunts at follow-up. Conclusion. TIPS creation in thrombosed portal vein is possible and might be a treatment option in certain patients.

  14. An improved reservoir for the flushing test to diagnose shunt insufficiency.

    PubMed

    Schlosser, Hans-Georg; Crawack, Hans-Joachim; Miethke, Christoph; Knitter, Thoralf; Zeiner, Andreas; Sprung, Christian

    2016-09-01

    OBJECTIVE Reservoirs integrated into hydrocephalus shunts are commonly used for the removal of CSF and for intra-ventricular pressure measurement. Pumping with the reservoir to diagnose shunt sufficiency is still a matter of controversy. The authors describe an improved flushing device and its characteristic features in vitro and in vivo. METHODS The flushing reservoir is constructed with a sapphire ball in a cage as a nonresistance valve to also enable the detection of distal occlusions. The most important reservoir parameters were investigated in vitro, simulating total and partial proximal and distal shunt occlusions. Then the expected advantages were assessed in vivo by evaluating the pump test data of 360 implanted reservoirs. The results were compared with those found in the literature. RESULTS The optimization of the technical parameters of the device, such as the high stroke volume in combination with moderate suction force, are obvious advantages compared with other flushing devices. Total occlusion of the ventricular catheter and the valve could be assessed with high certainty. The detection of a total obstruction of the peritoneal catheter or any partial obstruction is also possible, depending on its exact grade and location. CONCLUSIONS Shunt obstructions can be assessed using the pumping test. The reservoir construction presented here provides a clear enhancement of that diagnostic test.

  15. [Pulmonary arterial hypertension in congenital heart defects with shunt: a heterogeneous and complex constellation].

    PubMed

    Zimmermann, R; Schranz, D; Ewert, P; Kaemmerer, H

    2013-06-01

    It will be explained how pulmonary vascular disease can develop in congenital heart defects with primary left-to-right shunt across the different ages and stages of development, with and without surgical, interventional or medical treatment. Furthermore it will be discussed, in which specific stages of pulmonary vascular disease "advanced therapy" can be used.

  16. Evaluation of hepatic steatosis in dogs with congenital portosystemic shunts using Oil Red O staining.

    PubMed

    Hunt, G B; Luff, J A; Daniel, L; Van den Bergh, R

    2013-11-01

    The aims of this prospective study were to quantify steatosis in dogs with congenital portosystemic shunts (CPS) using a fat-specific stain, to compare the amount of steatosis in different lobes of the liver, and to evaluate intra- and interobserver variability in lipid point counting. Computer-assisted point counting of lipid droplets was undertaken following Oil Red O staining in 21 dogs with congenital portosystemic shunts and 9 control dogs. Dogs with congenital portosystemic shunts had significantly more small lipid droplets (<6 μ) than control dogs (P = .0013 and .0002, respectively). There was no significant difference in steatosis between liver lobes for either control dogs and CPS dogs. Significant differences were seen between observers for the number of large lipid droplets (>9 μ) and lipogranulomas per tissue point (P = .023 and .01, respectively). In conclusion, computer-assisted counting of lipid droplets following Oil Red O staining of liver biopsy samples allows objective measurement and detection of significant differences between dogs with CPS and normal dogs. This method will allow future evaluation of the relationship between different presentations of CPS (anatomy, age, breed) and lipidosis, as well as the impact of hepatic lipidosis on outcomes following surgical shunt attenuation.

  17. [INTERVENTIONAL AND SURGICAL TREATMENT OF THE ANGINA PECTORIS RECURRENCE AFTER CORONARY SHUNTING OPERATION].

    PubMed

    Fanta, S M

    2015-12-01

    There were examined 134 patients, in whom in the clinic in 2005-2014 yrs a coronary shunting operation was performed. In patients with the angina pectoris recurrence a reoperation is indicated. The data of repeated coronaroventriculography and shuntography were analyzed. Efficacy of the surgical and interventional methods application in the patients was proved.

  18. Percutaneous In Utero Thoracoamniotic Shunt Creation for Fetal Thoracic Abnormalities Leading to Non-Immune Hydrops

    PubMed Central

    White, Sarah B.; Tutton, Sean M.; Rilling, William S.; Kuhlmann, Randall S.; Peterson, Erika L.; Wigton, Thomas R.; Ames, Mary B.

    2015-01-01

    Purpose In a fetus, rare, fetal thoracic abnormalities can cause mediastinal shift and vena cava obstruction resulting in fetal hydrops and intra-uterine fetal demise. This series describes a trans-abdominal, trans-uterine Seldinger based percutaneous approach to create a shunt for treatment of these fetal abnormalities. Material and Methods Five fetuses presented with non-immune fetal hydrops due to fetal thoracic abnormalities causing severe mass effect. Under direct ultrasound guidance, an 18 G needle was used to access the malformation. Through a peel away sheath, a customized pediatric transplant 4.5 French double J ureteral stent was advanced; the leading loop was placed in the fetal thorax and the trailing end left outside the fetal thorax within the amniotic cavity. Results Seven thoracoamniotic shunts were successfully placed in 5 fetuses, with one shunt immediately replaced due to displacement during the procedure and the second not functioning at follow-up requiring insertion of a second shunt. All fetuses had successful decompression of the thoracic malformation, allowing lung re-expansion and resolution of hydrops. Three of 5 mothers had meaningful (> 7 days) prolongation of their pregnancies. All pregnancies were maintained to > 30 weeks, with a range of 30 weeks 1 day to 37 weeks 2 days. There were no maternal complications. Conclusions Seldinger based percutaneous approach to draining fetal thoracic abnormalities is feasible and can allow for prolongation of pregnancy, antenatal lung development and ultimately result in fetal survival. PMID:24702750

  19. Piezoelectric Shunt Vibration Damping of F-15 Panel under High Acoustic Excitation

    NASA Technical Reports Server (NTRS)

    Wu, Shu-Yau; Turner, Travis L.; Rizzi, Stephen A.

    2000-01-01

    At last year's SPIE symposium, we reported results of an experiment on structural vibration damping of an F-15 underbelly panel using piezoelectric shunting with five bonded PZT transducers. The panel vibration was induced with an acoustic speaker at an overall sound pressure level (OASPL) of about 90 dB. Amplitude reductions of 13.45 and 10.72 dB were achieved for the first and second modes, respectively, using single- and multiple-mode shunting. It is the purpose of this investigation to extend the passive piezoelectric shunt-damping technique to control structural vibration induced at higher acoustic excitation levels, and to examine the controllability and survivability of the bonded PZT transducers at these high levels. The shunting experiment was performed with the Thermal Acoustic Fatigue Apparatus (TAFA) at the NASA Langley Research Center using the same F-15 underbelly panel. The TAFA is a progressive wave tube facility. The panel was mounted in one wall of the TAFA test section using a specially designed mounting fixture such that the panel was subjected to grazing-incidence acoustic excitation. Five PZT transducers were used with two shunt circuits designed to control the first and second modes of the structure between 200 and 400 Hz. We first determined the values of the shunt inductance and resistance at an OASPL of 130 dB. These values were maintained while we gradually increased the OASPL from 130 to 154 dB in 6-dB steps. During each increment, the frequency response function between accelerometers on the panel and the acoustic excitation measured by microphones, before and after shunting, were recorded. Good response reduction was observed up to the 148dB level. The experiment was stopped at 154 dB due to wire breakage from vibration at a transducer wire joint. The PZT transducers, however, were still bonded well on the panel and survived at this high dB level. We also observed shifting of the frequency peaks toward lower frequency when the OASPL

  20. A physical framework for implementing virtual models of intracranial pressure and cerebrospinal fluid dynamics in hydrocephalus shunt testing.

    PubMed

    Venkataraman, Pranav; Browd, Samuel R; Lutz, Barry R

    2016-09-01

    OBJECTIVE The surgical placement of a shunt designed to resolve the brain's impaired ability to drain excess CSF is one of the most common treatments for hydrocephalus. The use of a dynamic testing platform is an important part of shunt testing that can faithfully reproduce the physiological environment of the implanted shunts. METHODS A simulation-based framework that serves as a proof of concept for enabling the application of virtual intracranial pressure (ICP) and CSF models to a physical shunt-testing system was engineered. This was achieved by designing hardware and software that enabled the application of dynamic model-driven inlet and outlet pressures to a shunt and the subsequent measurement of the resulting drainage rate. RESULTS A set of common physiological scenarios was simulated, including oscillations in ICP due to respiratory and cardiac cycles, changes in baseline ICP due to changes in patient posture, and transient ICP spikes caused by activities such as exercise, coughing, sneezing, and the Valsalva maneuver. The behavior of the Strata valve under a few of these physiological conditions is also demonstrated. CONCLUSIONS Testing shunts with dynamic ICP and CSF simulations can facilitate the optimization of shunts to be more failure resistant and better suited to patient physiology.

  1. A physical framework for implementing virtual models of intracranial pressure and cerebrospinal fluid dynamics in hydrocephalus shunt testing.

    PubMed

    Venkataraman, Pranav; Browd, Samuel R; Lutz, Barry R

    2016-09-01

    OBJECTIVE The surgical placement of a shunt designed to resolve the brain's impaired ability to drain excess CSF is one of the most common treatments for hydrocephalus. The use of a dynamic testing platform is an important part of shunt testing that can faithfully reproduce the physiological environment of the implanted shunts. METHODS A simulation-based framework that serves as a proof of concept for enabling the application of virtual intracranial pressure (ICP) and CSF models to a physical shunt-testing system was engineered. This was achieved by designing hardware and software that enabled the application of dynamic model-driven inlet and outlet pressures to a shunt and the subsequent measurement of the resulting drainage rate. RESULTS A set of common physiological scenarios was simulated, including oscillations in ICP due to respiratory and cardiac cycles, changes in baseline ICP due to changes in patient posture, and transient ICP spikes caused by activities such as exercise, coughing, sneezing, and the Valsalva maneuver. The behavior of the Strata valve under a few of these physiological conditions is also demonstrated. CONCLUSIONS Testing shunts with dynamic ICP and CSF simulations can facilitate the optimization of shunts to be more failure resistant and better suited to patient physiology. PMID:27203135

  2. Risk Factors for Tube Shunt Exposure: A Matched Case-Control Study

    PubMed Central

    Koval, Michael S.; El Sayyad, Fouad F.; Bell, Nicholas P.; Chuang, Alice Z.; Lee, David A.; Hypes, Stephen M.; Grover, Davinder S.; Baker, Laura A.; Huddleston, Stephen M.; Budenz, Donald L.; Feldman, Robert M.

    2013-01-01

    Purpose. To evaluate potential risk factors for developing tube shunt exposure in glaucoma patients. Patients and Methods. Forty-one cases from 41 patients that had tube shunt exposure from 1996 to 2005 were identified from the Robert Cizik Eye Clinic and Bascom Palmer Eye Institute. Each case was matched with 2 controls of the same gender and with tube shunts implanted within 6 months of the index case. Conditional logistic regression was used to determine risk factors. Results. The study cohort includes a total of 121 eyes from 121 patients. The mean age was 63.6 ± 19.7 years, ranging from 1 to 96 years. The average time to exposure was 19.29 ± 23.75 months (range 0.36–85.74 months). Risk factors associated with tube exposure were Hispanic ethnicity (P = 0.0115; OR = 3.6; 95% CI, 1.3–9.7), neovascular glaucoma (P = 0.0064; OR = 28.5; 95% CI, 2.6–316.9), previous trabeculectomy (P = 0.0070; OR = 5.3; 95% CI, 1.6–17.7), and combined surgery (P = 0.0381; OR = 3.7; 95% CI, 1.1–12.7). Conclusions. Hispanic ethnicity, neovascular glaucoma, previous trabeculectomy, and combined surgery were identified as potential risk factors for tube shunt exposure. These potential risk factors should be considered when determining the indication for performing tube shunt implantation and the frequency of long-term followup. PMID:23970955

  3. Metallurgical Effects of Shunting Current on Resistance Spot-Welded Joints of AA2219 Sheets

    NASA Astrophysics Data System (ADS)

    Jafari Vardanjani, M.; Araee, A.; Senkara, J.; Jakubowski, J.; Godek, J.

    2016-08-01

    Shunting effect is the loss of electrical current via the secondary circuit provided due to the existence of previous nugget in a series of welding spots. This phenomenon influences on metallurgical aspects of resistance spot-welded (RSW) joints in terms of quality and performance. In this paper RSW joints of AA2219 sheets with 1 mm thickness are investigated metallurgically for shunted and single spots. An electro-thermal finite element analysis is performed on the RSW process of shunted spot and temperature distribution and variation are obtained. These predictions are then compared with experimental micrographs. Three values of 5 mm, 20 mm, and infinite (i.e., single spot) are assumed for welding distance. Numerical and experimental results are matching each other in terms of nugget and HAZ geometry as increasing distance raised nugget size and symmetry of HAZ. In addition, important effect of shunting current on nugget thickness, microstructure, and Copper segregation on HAZ grain boundaries were discovered. A quantitative analysis is also performed about the influence of welding distance on important properties including ratio of nugget thickness and diameter ( r t), ratio of HAZ area on shunted and free side of nugget ( r HA), and ratio of equivalent segregated and total amount of Copper, measured in sample ( r Cu) on HAZ. Increasing distance from 5 mm to infinite, indicated a gain of 111.04, -45.55, and -75.15% in r t, r HA, and r Cu, respectively, while obtained ratios for 20 mm welding distance was suitable compared to single spot.

  4. Metallurgical Effects of Shunting Current on Resistance Spot-Welded Joints of AA2219 Sheets

    NASA Astrophysics Data System (ADS)

    Jafari Vardanjani, M.; Araee, A.; Senkara, J.; Jakubowski, J.; Godek, J.

    2016-06-01

    Shunting effect is the loss of electrical current via the secondary circuit provided due to the existence of previous nugget in a series of welding spots. This phenomenon influences on metallurgical aspects of resistance spot-welded (RSW) joints in terms of quality and performance. In this paper RSW joints of AA2219 sheets with 1 mm thickness are investigated metallurgically for shunted and single spots. An electro-thermal finite element analysis is performed on the RSW process of shunted spot and temperature distribution and variation are obtained. These predictions are then compared with experimental micrographs. Three values of 5 mm, 20 mm, and infinite (i.e., single spot) are assumed for welding distance. Numerical and experimental results are matching each other in terms of nugget and HAZ geometry as increasing distance raised nugget size and symmetry of HAZ. In addition, important effect of shunting current on nugget thickness, microstructure, and Copper segregation on HAZ grain boundaries were discovered. A quantitative analysis is also performed about the influence of welding distance on important properties including ratio of nugget thickness and diameter (r t), ratio of HAZ area on shunted and free side of nugget (r HA), and ratio of equivalent segregated and total amount of Copper, measured in sample (r Cu) on HAZ. Increasing distance from 5 mm to infinite, indicated a gain of 111.04, -45.55, and -75.15% in r t, r HA, and r Cu, respectively, while obtained ratios for 20 mm welding distance was suitable compared to single spot.

  5. Is color-Doppler US a reliable method in the follow-up of transjugular intrahepatic portosystemic shunt (TIPS)?

    PubMed Central

    Ricci, P.; Cantisani, V.; Lombardi, V.; Alfano, G.; D'Ambrosio, U.; Menichini, G.; Marotta, E.; Drudi, F.M.

    2007-01-01

    Transjugular intrahepatic portosystemic shunt (TIPS) has become a widely accepted treatment for complications of portal hypertension. Shunt or hepatic vein stenoses or occlusions are common short- and mid-term complications of the procedure, with a one-year primary patency ranging from 25% to 66%. When promptly identified, shunt stenosis or occlusion may be treated before the recurrence of gastrointestinal bleeding or ascites. The revision is usually successful and the primary-assisted patency of TIPS is approximately 85% at one year. Doppler sonography is a widely accepted screening modality for TIPS patients, both as a routine follow-up in asymptomatic patients and in those cases with clinically suspected TIPS malfunction. In a routine US follow-up, a TIPS patient is scheduled for a control 24 h after the procedure, and then after one week, 1 month, 3 months, and at 3-month intervals thereafter. Venography is at present performed solely on the basis of a suspected shunt dysfunction during the sonographic examination. Color-Doppler sonography is the most reliable method for monitoring the shunt function after TIPS implantation. Several studies have shown that Doppler sonography is a sensitive and relatively specific way to detect shunt malfunction, particularly when multiple parameters are examined. Achieving high sensitivity is optimal so that malfunctioning shunts can be identified and shunt revision can be performed before symptomatic deterioration. Venous angiography is at present indicated only on the basis of US suspicion of shunt compromise. Power-Doppler US and US contrast media can be useful in particular conditions, but are not really fundamental. PMID:23396711

  6. Thoratec HeartMate II(®) left ventricular assist device implantation in patient with patent ventriculoperitoneal shunt.

    PubMed

    Yamane, Kentaro; Bogar, Linda J; Tabata, Shigeki; Hirose, Hitoshi

    2012-01-01

    We report a case of HeartMate II(®) left ventricular assist device (LVAD) implantation as a destination therapy in a patient with a patent ventriculoperitoneal (VP) shunt after being suffered from subarachnoid hemorrhage. Because the patient's VP shunt was running through her right anterior chest and abdominal wall, a driveline exit site was selected in her left upper quadrant to avoid unnecessary perioperative complication in relation to the patent VP shunt tube. Tailored driveline placement was a key element of this LVAD implantation in this already sick patient with multiple comorbidities.

  7. Vascular plug-assisted retrograde transvenous obliteration of portosystemic shunts for refractory hepatic encephalopathy: a case report.

    PubMed

    Park, Jonathan K; Cho, Sung-Ki; Kee, Stephen; Lee, Edward W

    2014-01-01

    While balloon-assisted retrograde transvenous obliteration (BRTO) has been used for two decades in Asia for the management of gastric variceal bleeding, it is still an emerging therapy elsewhere. Given the shunt closure brought about by the procedure, BRTO has also been used for the management of portosystemic encephalopathy with promising results. Modified versions of BRTO have been developed, including plug-assisted retrograde transvenous obliteration (PARTO), where a vascular plug is deployed within a portosystemic shunt. To our knowledge, we present the first North American case of PARTO in the setting of a large splenorenal shunt for the management of portosystemic encephalopathy.

  8. Differential effects on portal and effective hepatic blood flow. A comparison between transjugular intrahepatic portasystemic shunt and small-diameter H-graft portacaval shunt.

    PubMed Central

    Rosemurgy, A S; Zervos, E E; Goode, S E; Black, T J; Zwiebel, B R

    1997-01-01

    OBJECTIVE: This study was undertaken to determine the effects of transjugular intrahepatic portasystemic shunt (TIPS) and small-diameter prosthetic H-graft portacaval shunt (HGPCS) on portal and effective hepatic blood flow. SUMMARY BACKGROUND DATA: Mortality after TIPS is higher than after HGPCS for bleeding varices. This higher mortality is because of hepatic failure, possibly a result of excessive diminution of hepatic blood flow. METHODS: Forty patients randomized prospectively to undergo TIPS or HGPCS had effective hepatic blood flow determined 1 day preshunt and 5 days postshunt using low-dose galactose clearance. Portal blood flow was determined using color-flow Doppler ultrasound. RESULTS: Treatment groups were similar in age, gender, and Child's class. Each procedure significantly reduced portal pressures and portasystemic pressure gradients. Portal flow after TIPS increased (21 mL/second +/- 11.9 to 31 mL/second +/- 16.9, p < 0.05), whereas it remained unchanged after HGPCS (26 mL/second +/- 27.7 to 14 mL/second +/- 41.1, p = n.s.). Effective hepatic blood flow was diminished significantly after TIPS (1684 mL/minute +/- 2161 to 676 mL/minute +/- 451, p < 0.05) and was unaffected by HGPCS (1901 mL/ minute +/- 1818 to 1662 mL/minute +/- 1035, p = n.s.). CONCLUSIONS: Both TIPS and HGPCS achieved significant reductions in portal vein pressure gradients. Portal flow increased after TIPS, although most portal flow was diverted through the shunt. Effective hepatic flow is reduced significantly after TIPS but well preserved after HGPCS. Hepatic decompensation and mortality after TIPS may be because, at least in part, of reductions in nutrient hepatic flow. PMID:9193187

  9. Ventriculoperitoneal shunt and the need to remove a gallbladder: Time to definitely overcome the feeling that laparoscopic surgery is contraindicated

    PubMed Central

    Cobianchi, Lorenzo; Dominioni, Tommaso; Filisetti, Claudia; Zonta, Sandro; Maestri, Marcello; Dionigi, Paolo; Alessiani, Mario

    2014-01-01

    Since Baskin et al. reported the first documented case of failure of a laparoscopically-induced ventriculoperitoneal shunt (VP) in 1998, the cerebrospinal fluid shunt has been generally considered a relative contraindication to laparoscopy. Although the literature is limited there is a small body of evidence indicating that it is safe to perform laparoscopic surgery on these patients with routine anaesthetic monitoring. In this study we report the case of a laparoscopic cholecystectomy in the presence of a ventriculoperitoneal shunt. A review of the literature suggests that laparoscopic cholecystectomy can be safely performed in patients with a ventriculoperitoneal shunt. The only related contraindication should be if a catheter has recently been placed. PMID:25568789

  10. Ventriculoperitoneal shunt and the need to remove a gallbladder: Time to definitely overcome the feeling that laparoscopic surgery is contraindicated.

    PubMed

    Cobianchi, Lorenzo; Dominioni, Tommaso; Filisetti, Claudia; Zonta, Sandro; Maestri, Marcello; Dionigi, Paolo; Alessiani, Mario

    2014-09-01

    Since Baskin et al. reported the first documented case of failure of a laparoscopically-induced ventriculoperitoneal shunt (VP) in 1998, the cerebrospinal fluid shunt has been generally considered a relative contraindication to laparoscopy. Although the literature is limited there is a small body of evidence indicating that it is safe to perform laparoscopic surgery on these patients with routine anaesthetic monitoring. In this study we report the case of a laparoscopic cholecystectomy in the presence of a ventriculoperitoneal shunt. A review of the literature suggests that laparoscopic cholecystectomy can be safely performed in patients with a ventriculoperitoneal shunt. The only related contraindication should be if a catheter has recently been placed.

  11. Stability of Programmable Shunt Valve Settings with Simultaneous Use of the Optune Transducer Array: A Case Report.

    PubMed

    Chan, Andrew K; Birk, Harjus S; Winkler, Ethan A; Viner, Jennifer A; Taylor, Jennie W; McDermott, Michael W

    2016-07-07

    The Optune® transducer array (Novocure Ltd., Haifa, Israel) is an FDA-approved noninvasive regional therapy that aims to inhibit the growth of glioblastoma multiforme (GBM) cells via utilization of alternating electric fields. Some patients with GBM may develop hydrocephalus and benefit from subsequent shunt placement, but special attention must be paid to patients in whom programmable valves are utilized, given the potential effect of the magnetic fields on valve settings. We present the first case report illustrating the stability of programmable shunt valve settings in a neurosurgical patient undergoing therapy with the Optune device. In this study, shunt valve settings were stable over a period of five days despite Optune therapy. This is reassuring for patients with GBM who require simultaneous treatment with both the Optune device and a programmable shunt system.

  12. Hepatic encephalopathy due to intrahepatic portosystemic venous shunt successfully treated by balloon occluded retrograde transvenous embolization with GDCs.

    PubMed

    Yamagami, Takuji; Yoshimatsu, Rika; Miura, Hiroshi; Hasebe, Terumitsu; Koide, Kazuma

    2012-01-01

    We report a 65-year-old man with hepatic encephalopathy due to an intrahepatic portosystemic venous shunt that was successfully occluded by balloon occluded retrograde transvenous embolization with Guglielmi and interlocking detachable coils as performed percutaneously.

  13. Hepatic encephalopathy due to intrahepatic portosystemic venous shunt successfully treated by balloon occluded retrograde transvenous embolization with GDCs

    PubMed Central

    Yamagami, Takuji; Yoshimatsu, Rika; Miura, Hiroshi; Hasebe, Terumitsu; Koide, Kazuma

    2012-01-01

    We report a 65-year-old man with hepatic encephalopathy due to an intrahepatic portosystemic venous shunt that was successfully occluded by balloon occluded retrograde transvenous embolization with Guglielmi and interlocking detachable coils as performed percutaneously. PMID:23986827

  14. Exit ventriculoperitoneal shunt; enter endoscopic third ventriculostomy (ETV): contemporary views on hydrocephalus and their implications on management.

    PubMed

    Kamalo, P

    2013-09-01

    Hydrocephalus has been known to affect humans since the birth of human medicine as it is described by Hippocrates. The management of this condition is however still dodged by challenges due to a poor understanding of its pathophysiology. The ventriculoperitoneal shunt presents considerable problems especially with respect to infection and shunt malfunction. Low income countries, that currently face the greater burden of paediatric hydrocephalus. experience an increased challenge with ventriculoperitoneal shunts due to a shortage of qualified personnel to handle shunt complications. Recent advances in neuro-endoscopic surgery have presented opportunities for alternative treatment options for hydrocephalus such as endoscopic third ventriculostomy (ETV). This paper explores the alternative views in the pathophysiology of hydrocephalus and how they explain the effectiveness of ETV in treating hydrocephalus arising from a variety of causes. PMID:24358424

  15. Stability of Programmable Shunt Valve Settings with Simultaneous Use of the Optune Transducer Array: A Case Report.

    PubMed

    Chan, Andrew K; Birk, Harjus S; Winkler, Ethan A; Viner, Jennifer A; Taylor, Jennie W; McDermott, Michael W

    2016-01-01

    The Optune® transducer array (Novocure Ltd., Haifa, Israel) is an FDA-approved noninvasive regional therapy that aims to inhibit the growth of glioblastoma multiforme (GBM) cells via utilization of alternating electric fields. Some patients with GBM may develop hydrocephalus and benefit from subsequent shunt placement, but special attention must be paid to patients in whom programmable valves are utilized, given the potential effect of the magnetic fields on valve settings. We present the first case report illustrating the stability of programmable shunt valve settings in a neurosurgical patient undergoing therapy with the Optune device. In this study, shunt valve settings were stable over a period of five days despite Optune therapy. This is reassuring for patients with GBM who require simultaneous treatment with both the Optune device and a programmable shunt system. PMID:27551653

  16. Stability of Programmable Shunt Valve Settings with Simultaneous Use of the Optune Transducer Array: A Case Report

    PubMed Central

    Chan, Andrew K; Winkler, Ethan A; Viner, Jennifer A; Taylor, Jennie W; McDermott, Michael W.

    2016-01-01

    The Optune® transducer array (Novocure Ltd., Haifa, Israel) is an FDA-approved noninvasive regional therapy that aims to inhibit the growth of glioblastoma multiforme (GBM) cells via utilization of alternating electric fields. Some patients with GBM may develop hydrocephalus and benefit from subsequent shunt placement, but special attention must be paid to patients in whom programmable valves are utilized, given the potential effect of the magnetic fields on valve settings. We present the first case report illustrating the stability of programmable shunt valve settings in a neurosurgical patient undergoing therapy with the Optune device. In this study, shunt valve settings were stable over a period of five days despite Optune therapy. This is reassuring for patients with GBM who require simultaneous treatment with both the Optune device and a programmable shunt system. PMID:27551653

  17. MRI-Monitored Intra-Shunt Local Agent Delivery of Motexafin Gadolinium: Towards Improving Long-Term Patency of TIPS

    PubMed Central

    Meng, Yanfeng; Zhang, Tong; Willis, Patrick; Le, Thomas; Soriano, Stephanie; Ray, Erik; Valji, Karim; Zhang, Guixiang; Yang, Xiaoming

    2013-01-01

    Background Transjugular intrahepatic portosystemic shunt (TIPS) has become an important and effective interventional procedure in treatment of the complications related to portal hypertension. Although the primary patency of TIPS has been greatly improved due to the clinical application of cover stent-grafts, the long-term patency is still suboptimal. This study was to investigate the feasibility of using magnetic resonance imaging (MRI)-monitored intra-shunt local agent delivery of motexafin gadolinium (MGd) into shunt-vein walls of TIPS. This new technique aimed to ultimately inhibit shuntstenosis of TIPS. Methodology Human umbilical vein smooth muscle cells (SMCs) were incubated with various concentrations of MGd, and then examed by confocal microscopy and T1-map MRI. In addition, the proliferation of MGd-treated cells was evaluated. For in vivo validation, seventeen pigs underwent TIPS. Before placement of the stent, an MGd/trypan-blue mixture was locally delivered, via a microporous balloon, into eleven shunt-hepatic vein walls under dynamic MRI monitoring, while trypan-blue only was locally delivered into six shunt-hepatic vein walls as serve as controls. T1-weighted MRI of the shunt-vein walls was achieved before- and at different time points after agent injections. Contrast-to-noise ratio (CNR) of the shunt-vein wall at each time-point was measured. Shunts were harvested for subsequent histology confirmation. Principal Findings In vitro studies confirmed the capability of SMCs in uptaking MGds in a concentration-dependent fashion, and demonstrated the suppression of cell proliferation by MGds as well. Dynamic MRI displayed MGd/blue penetration into the shunt-vein walls, showing significantly higher CNR of shunt-vein walls on post-delivery images than on pre-delivery images (49.5±9.4 vs 11.2±1.6, P<0.01), which was confirmed by histology. Conclusion Results of this study indicate that MRI-monitored intra-shunt local MGd delivery is feasible and MGd

  18. [Unilateral Posterior Reversible Encephalopathy Syndrome after Ventriculo-Peritoneal Shunt for Normal Pressure Hydrocephalus Following Subarachnoid Hemorrhage: A Case Report].

    PubMed

    Sato, Hiroyuki; Koizumi, Takayuki; Sato, Daisuke; Endo, Shin; Kato, Syunichi

    2016-06-01

    The patient, a 79-year-old man, experienced a Hunt & Kosnik grade IV subarachnoid hemorrhage, presenting with sudden-onset coma and severe left hemiplegia. We performed cranial clipping surgery for a ruptured aneurysm on the right middle cerebral artery the same day. Post-operative recovery proceeded smoothly, with gradual improvements in disturbed consciousness and left hemiplegia. Three weeks post-operation, CT revealed low-density areas in the right frontal and temporal lobe, believed to be due to subarachnoid hemorrhage, as well as hydrocephaly. We then performed a lumbo-peritoneal (L-P) shunt for the hydrocephaly. Two months later, the patient experienced shunt occlusion, and we performed a ventriculo-peritoneal (V-P) shunt revision (pressure: 6 cm H(2)O). Headaches, severe decline in cognitive function, and worsened left hemiplegia were observed seven weeks post-shunt revision. Cranial CT revealed widespread low-density areas in right posterior cerebral white matter. We suspected unilateral posterior reversible encephalopathy syndrome (PRES) after performing cranial MRI and cerebral angiography. Increasing the set pressure of the shunt improved the symptoms and radiographic findings. PRES is typically bilateral, and unilateral incidents are rare. This is the first report of unilateral PRES secondary to shunt operation. Its unilaterality appears to have been caused by unilateral brain damage or adhesions to the brain surface from the subarachnoid cerebral hemorrhage. Overdrainage post-shunt can also induce PRES. Diagnosis of PRES is more difficult in unilateral cases;practitioners must keep PRES in mind as a rare complication post-shunt operation. PMID:27270150

  19. Quantitative, non-invasive assessment of ventricular septal defect shunt flow by measuring proximal isovelocity surface area on colour Doppler mapping.

    PubMed Central

    Kurotobi, S.; Sano, T.; Matsushita, T.; Takeuchi, M.; Kogaki, S.; Miwatani, T.; Okada, S.

    1997-01-01

    OBJECTIVE: To determine whether the proximal isovelocity surface area (PISA) method could be applied to estimate the magnitude of ventricular septal defect (VSD) shunt flow. DESIGN: Prospective analysis of clinical, echocardiographic, and angiographic data. SETTING: University hospital. PATIENTS: 14 children with VSD. METHODS: Colour Doppler images of VSD shunt flow were obtained in parasternal long axis view, four chamber view or both, adjusted to provide the best imaging of flow. The VSD shunt flow rate and shunt volume were calculated as follows: shunt flow rate (SFR) = 2 pi r2 V/BSA in ml/s/m2; shunt volume = SFR x shunt duration time. The shunt volume, shunt fraction, and pulmonary to systemic flow ratio (Qp:Qs) were confirmed by cardiac catheterisation. RESULTS: There was a correlation between shunt variables determined by PISA and those by catheterisation, including shunt volume (r = 0.78, P = 0.001) and shunt fraction (r = 0.74, P = 0.003). Qp:Qs was also significantly correlated with SFR (r = 0.79, P = 0.0007). The SFR was significantly different between the four patients with Qp:Qs < 2.0 (mean (SD) 54 (33) ml/s/m2) and the 10 patients with Qp:Qs > 2.0 (186 (69) ml/s/m2) (P = 0.004). CONCLUSIONS: These data suggest that the PISA method is a reliable non-invasive investigation for the quantitative assessment of VSD shunt flow and provides important information for decisions regarding surgical repair. Images PMID:9391295

  20. Options Studied for Managing Space Station Solar Array Electrical Hazards for Sequential Shunt Unit Replacement

    NASA Technical Reports Server (NTRS)

    Delleur, Ann M.; Kerslake, Thomas W.; Levy, Robert K.

    2004-01-01

    The U.S. solar array strings on the International Space Station are connected to a sequential shunt unit (SSU). The job of the SSU is to shunt, or short, the excess current from the solar array, such that just enough current is provided downstream to maintain the 160-V bus voltage while meeting the power load demand and recharging the batteries. Should an SSU fail on-orbit, it would be removed and replaced with the on-orbit spare during an astronaut space walk or extravehicular activity (EVA) (see the photograph). However, removing an SSU during an orbit Sun period with input solar array power connectors fully energized could result in substantial hardware damage and/or safety risk to the EVA astronaut. The open-circuit voltage of cold solar-array strings can exceed 320 V, and warm solar-array strings could feed a short circuit with a total current level exceeding 240 A.

  1. Arterial and venous embolization: Declotting of dialysis shunts by direct injection of streptokinase

    SciTech Connect

    Zeit, R.M.

    1986-06-01

    During the past 33 months, thrombolysis of 79 clotted hemodialysis shunts was attempted by injecting small quantities of dilute streptokinase solution directly into the clotted shunt, followed by massage of the clot. Embolization of clot fragments in six of 79 cases (7.6%) was demonstrated angiographically. In four of the six cases embolization involved the brachial artery or its branches. In one case embolization involved an arm vein, and in one case embolization involved both the bracial artery and axillary vein. All patients remained asymptomatic, and repeat angiographic study, usually performed the following day, showed resolution of the emboli in four of five cases. The incidence of embolization in direct-injection thrombolysis reported in this study appears to be comparable to that reported in studies using the streptokinase infusion technique.

  2. Armored brain in patients with hydrocephalus after shunt surgery: review of the literatures.

    PubMed

    Taha, Mahmoud M

    2012-01-01

    Armored brain or chronic calcified subdural hematoma is a rare complication of cerebrospinal fluid diversion with few cases reported in the literature. Seventeen patients with this pathology have been published. A complete review of the literatures regarding this topic has been collected and discussed. The author also presents a 12- year old boy with triventricular hydrocephalus who had undergone ventriculoperitoneal medium pressure shunt system since birth. The patient presented to our clinic with a 2-year history of seizures. The patient was conscious and without neurological deficits on examination. Computed tomography of the brain showed bilateral high density mass with surface calcification. X ray skull and MRI confirmed the calcified subdural hematoma bilaterally. We preferred conservative treatment and the patient continued his antiepileptic treatment. At one year follow up, the patient had the same neurological state. The case highlights the importance of frequent follow up CT brain after shunt surgery.

  3. The early serological detection of colonisation by Staphylococcus epidermidis of ventriculo-atrial shunts.

    PubMed

    Holt, R

    1980-01-01

    Simple quantitative serological tests demonstrating Staphylococcus epidermidis agglutinins and C-reactive protein were used for the early detection of ventriculo-atrial shunt colonization by this organism. Tests in normal children and adults in various age groups throughout life confirmed Bayston's ovservations that those tested attained a titre up to 1:160 TO S. epidermidis agglutinogen. In contrast, the titre in children with colonised shunts and in adults with S. epidermidis endocarditis, both conditions which are usually accompanied by bacteraemia, rose to much higher levels, sometimes up to 1:5120. The routine combination of both tests has proven to be of considerable diagnostic value, particularly in early or recent colonisation. PMID:7372358

  4. Atlantoaxial Rotatory Subluxation after Removal of a Ventriculoperitoneal Shunt in the Supine-Lateral Position.

    PubMed

    Hashide, Shusei; Aihara, Yasuo; Nagahara, Ayumi; Mitsuyama, Tetsuryu; Okada, Yoshikazu

    2015-01-01

    Atlantoaxial rotatory subluxation (AARS) is an uncommon disease with a greater prevalence in children than adults. So far there has only been one report of AARS after surgery related to ventriculoperitoneal (VP) shunting. We present a new case of AARS closed reduction treatment after VP shunt removal in an 8-year-old girl with wound pain on the back of her head and torticollis after surgery. Her head was rotated in the spine-lateral position during surgery. The diagnosis of AARS was established by 3D-computed tomography. The rotatory subluxation was cured after cervical traction therapy. The successful closed reduction was the consequence of early detection and conservative treatment, which are important constituents in the management of AARS. PMID:26202450

  5. Reduction of Switching Surge by Controlled Shunt Reactor Switching of Gas Circuit Breaker

    NASA Astrophysics Data System (ADS)

    Kohyama, Haruhiko; Ito, Hiroki; Asai, Jun; Hidaka, Mikio; Yonezawa, Takashi

    Controlled switching system (CSS) with a 204kV gas circuit breaker (GCB) demonstrates to reduce an inrush current and to eliminate re-ignitions in shunt reactor switching. Target closing and opening instants for controlled switching are determined by the electrical and mechanical characteristics of GCB. Idle time dependence of the operating time, which gives a sufficient impact on controlling accuracy, is evaluated and successfully compensated by synchronous switching controller (SSC). Field operation of CSS for a year shows an effective suppression of inrush current on closing and prevention of re-ignitions on opening of shunt reactor. The operations also proved that the CSS has a satisfactory performance for electro-magnetic disturbance imposed in practical field.

  6. Comparison of 2D transmon coherence for different capacitive shunt fabrication methods

    NASA Astrophysics Data System (ADS)

    Yoder, Jonilyn; Kamal, Archana; Yan, Fei; Gudmundsen, Theodore; Welander, Paul; Gustavsson, Simon; Hover, David; Kerman, Andrew; Sears, Adam; Oliver, William

    2015-03-01

    Improvements in superconducting qubit coherence times and reproducibility have been demonstrated using capacitive shunting. In this study, we present a side-by-side comparison of two distinct methods for preparing the aluminum shunt capacitor material for 2D transmon superconducting qubit devices. The first method involved in situ wafer outgassing prior to molecular beam epitaxy aluminum evaporation. The second method involved ex situ wafer annealing prior to electron gun aluminum evaporation. Materials analysis for each process will be detailed. Experimental results, including qubit coherence times and superconducting coplanar waveguide resonator internal quality factors, will be presented for representative devices prepared using both methods. This work is sponsored by the Assistant Secretary of Defense for Research and Engineering under Air Force Contract FA8721-05-0002. Opinions, interpretations, conclusions, and recommendations are those of the authors and are not necessarily endorsed by the United States Government.

  7. Gate assisted turn-off thyristor with cathode shunts and dynamic gate

    NASA Technical Reports Server (NTRS)

    Schlegel, E. S.; Page, D. J.

    1976-01-01

    A 1,000-V, 200-A gate-assisted turn-off thyristor (GATT) is described, whose design features include an interdigitated shunted cathode, a dynamic gate, a means for optimizing the carrier lifetime level, and a bypass diode. The device physics of gate-assisted turn-off are reviewed. Based on this, improvements in the design are described. It is shown that a prime failure mode can be eliminated and that the gate-assist signal voltage can be substantially decreased by employing a shunted cathode emitter. The test data show excellent turn-on characteristics due to the dynamic gate and the long perimeter of the edge of the main cathode. Turn-off times as short as 3 microsec are obtained. The combination of controlling the carrier lifetime with a precisely controlled and easily variable irradiation dose of high energy electrons with gate assist current provides for simple, precision tailoring of the device characteristics to the intended application.

  8. Vesico-amniotic shunting for lower urinary tract obstruction in a fetus with VACTERL association.

    PubMed

    Kanasugi, Tomonobu; Kikuchi, Akihiko; Haba, Gen; Sasaki, Yuri; Isurugi, Chizuko; Oyama, Rie; Sugiyama, Toru

    2016-09-01

    Newborn cases of VACTERL association with lower urinary tract obstruction (LUTO) are rare and there have been no reports on those patients undergoing fetal therapy in English literature. We successfully performed vesico-amniotic shunting in a fetus having LUTO caused by abnormality of the external genitalia at 16 weeks' gestation. Although fetal karyotype was normal 46XY, follow-up fetal ultrasound examinations revealed ventriculomegaly in the brain, a small stomach and a right multicystic dysplastic kidney. MRI at 31 weeks' gestation suggested lobar type holoprosencephaly. Diagnosis of VACTERL association was confirmed postnatally. We consider that vesico-amniotic shunting is indicated for a fetus of VACTERL association with LUTO if the parents wish the procedure after genetic counseling and explanations about the fetal conditions.

  9. A novel low-profile ventriculoamniotic shunt for foetal aqueductal stenosis.

    PubMed

    Chen, Yanfei; Emery, Stephen P; Maxey, Antonina P; Gu, Xinzhu; Wagner, William R; Chun, Youngjae

    2016-01-01

    This study proposed a novel ventriculoamniotic shunt device for foetal aqueductal stenosis treatment fabricated with 3Fr or 4Fr size catheters that have a longitudinal bending stiffness with kink resistance, sufficient luminal area for cerebrospinal fluid drainage and capacity for valve integration. Computational flow dynamics studies were carried out to optimise the device design, including size of the lumen and length of the device. An in vitro pressure and flow rate measurement test circuit was constructed to assess the high pressure relieving functionality of draining cerebrospinal fluid from foetal brain. Additionally, a resistance force measurement test platform was built to quantitatively evaluate the anchor performance of various geometric designs. The valve functionality was qualitatively evaluated through the visualisation of the flow patterns in the amniotic sac with injected red coloured fluid under stereomicroscopy. These in vitro results demonstrate the feasibility of the ventriculoamniotic shunt device designed for placement in the foetal brain. PMID:27004923

  10. Integration of Thermal Energy Harvesting in Semi-Active Piezoelectric Shunt-Damping Systems

    NASA Astrophysics Data System (ADS)

    Lubieniecki, Michał; Uhl, Tadeusz

    2015-01-01

    The opportunities to energize a broad range of devices by use of energy available almost anywhere and in many forms are almost unlimited. A major advantage of energy harvesting is the manufacture of small autonomous electronic devices with no need for power supply and maintenance. Shunt damping circuits, although unfavorably affected by the size and mass of bulky coil inductors, started to base on synthetic inductors losing their passivity. In this paper we report a study of the feasibility of powering shunt damping circuits by use of thermal energy otherwise irrevocably lost from a bearing. The heat generated in the bearing is converted thermoelectrically into electric energy which is then used to power synthetic inductance circuitry. We show that the power demand of such circuit can be satisfied by use of a thermoelectric generator paired with a moderately loaded bearing.

  11. On-line process analysis innovation: DiComp (tm) shunting dielectric sensor technology

    NASA Technical Reports Server (NTRS)

    Davis, Craig R.; Waldman, Frank A.

    1993-01-01

    The DiComp Shunting Dielectric Sensor (SDS) is a new patent-pending technology developed under the Small Business Innovation Research Program (SBIR) for NASA's Kennedy Space Center. The incorporation of a shunt electrode into a conventional fringing field dielectric sensor makes the SDS uniquely sensitive to changes in material dielectric properties in the KHz to MHz range which were previously detectable only at GHz measurement frequencies. The initial NASA application of the SDS for Nutrient Delivery Control has demonstrated SDS capabilities for thickness and concentration measurement of Hoagland nutrient solutions. The commercial introduction of DiComp SDS technology for concentration and percent solids measurements in dispersions, emulsions and solutions represents a new technology for process measurements for liquids in a variety of industries.

  12. Vesico-amniotic shunting for lower urinary tract obstruction in a fetus with VACTERL association.

    PubMed

    Kanasugi, Tomonobu; Kikuchi, Akihiko; Haba, Gen; Sasaki, Yuri; Isurugi, Chizuko; Oyama, Rie; Sugiyama, Toru

    2016-09-01

    Newborn cases of VACTERL association with lower urinary tract obstruction (LUTO) are rare and there have been no reports on those patients undergoing fetal therapy in English literature. We successfully performed vesico-amniotic shunting in a fetus having LUTO caused by abnormality of the external genitalia at 16 weeks' gestation. Although fetal karyotype was normal 46XY, follow-up fetal ultrasound examinations revealed ventriculomegaly in the brain, a small stomach and a right multicystic dysplastic kidney. MRI at 31 weeks' gestation suggested lobar type holoprosencephaly. Diagnosis of VACTERL association was confirmed postnatally. We consider that vesico-amniotic shunting is indicated for a fetus of VACTERL association with LUTO if the parents wish the procedure after genetic counseling and explanations about the fetal conditions. PMID:27061706

  13. Role of lipid-induced changes in plasma membrane in the biophysical shunt theory of psychopathology.

    PubMed

    Naisberg, Y; Weizman, A

    1997-04-01

    The existence of a lipid factor that either causes faulty lipid metabolism or directly contributes to the emergence of a biophysical shunt in neuronal membrane ionic flow propagation is proposed. The neuronal membrane contains a remarkable amount of phospholipids, glycolipids and cholesterol. It is assumed that, under certain unfavorable intrinsic states, the plasma membrane's lipid order and composition and, consequently, its cholesterol-to-phospholipid ratio, may change. This, in turn, may significantly modify membrane fluidity, altering the essential physical properties in the affected portions of the membrane and causing a disarray in the adjacent ion channels, leading to the establishment of a biophysical shunt in a loop-like operation, forming the basis for a variety of mental disorders. The present model offers a diet-induced lipid correction for the relief of psychopathological problems.

  14. Impact of aortocaval shunt flow on cardiac and renal function in unilateral nephrectomized rats

    PubMed Central

    Wu, Jie; Cheng, Zhong; Zhang, Mingjing; Zhu, Pengfei; Gu, Ye

    2016-01-01

    We previously reported significantly enhanced cardiac remodeling post aortocaval fistula (AV) in unilateral nephrectomized (UNX) rats. However, the relationship between the size of the AV and the cardiorenal effects in UNX rats remains unknown. In the present study, AV was induced by 20, 18 and 16 gauge needles in UNX rats to see if larger shunt would definitely induce heavier cardiac and renal damage in UNX rats. Our results demonstrated that bigger shunt size is linked with proportional more significant cardiorenal remodeling and dysfunction in UNX rats. Expression of inflammatory biomarkers including CRP, TNF-α, IL-6, IL-1β, TGF-β and MCP-1 in left kidney and heart was significantly increased in all UNX + AV groups compared to Sham rats. Inflammation might thus participate in the worsening cardiorenal functions and remodeling processes in this model. PMID:27279232

  15. Design and Implementation of Takagi-Sugeno Fuzzy Logic Controller for Shunt Compensator

    NASA Astrophysics Data System (ADS)

    Singh, Alka; Badoni, Manoj

    2016-12-01

    This paper describes the application of Takagi-Sugeno (TS) type fuzzy logic controller to a three-phase shunt compensator in power distribution system. The shunt compensator is used for power quality improvement and has the ability to provide reactive power compensation, reduce the level of harmonics in supply currents, power factor correction and load balancing. Additionally, it can also be used to regulate voltage at the point of common coupling (PCC). The paper discusses the design of TS fuzzy logic controller and its implementation based on only four rules. The smaller number of rules makes it suitable for experimental verification as compared to Mamdani fuzzy controller. A small laboratory prototype of the system is developed and the control algorithm is verified experimentally. The TS fuzzy controller is compared with the proportional integral based industrial controller and their performance is compared under a wide variation of dynamic load changes.

  16. Application of VSC-HVDC with Shunt Connected SMES for Compensation of Power Fluctuation

    NASA Astrophysics Data System (ADS)

    Linn, Zarchi; Kakigano, Hiroaki; Miura, Yushi; Ise, Toshifumi

    This paper describes the application of VSC-HVDC (High Voltage DC Transmission using Voltage Source Converter) with shunt connected SMES (Superconducting Magnetic Energy Storage) for compensation of power fluctuation caused by fluctuating power source such as photovoltaics and wind turbines. The objectives of this proposed system is to smooth out fluctuating power in one terminal side of HVDC in order to avoid causing power system instability and frequency deviation by absorbing or providing power according to the system requirement while another terminal side power is fluctuated. The shunt connected SMES charges and discharges the energy to and from the dc side and it compensates required power of fluctuation to obtain constant power flow in one terminal side of VSC-HVDC system. This system configuration has ability for power system stabilization in the case of power fluctuation from natural energy source. PSCAD/EMTDC simulation is used to evaluate the performance of applied system configuration and control method.

  17. Programmable shunt valves: in vitro assessment of safety of the magnetic field generated by a portable game machine.

    PubMed

    Nakashima, Koji; Nakajo, Takato; Kawamo, Michiari; Kato, Akihito; Ishigaki, Seiichiro; Murakami, Hidetomo; Imaizumi, Yohichi; Izumiyama, Hitoshi

    2011-01-01

    Cerebrospinal fluid (CSF) shunts are frequently used to treat hydrocephalus. The use of a programmable shunt valve allows physicians to easily change the opening pressure. Since patients with adjustable CSF shunt valves may use portable game machines, the permanent magnets in these machines may alter the shunt valve programmed settings or permanently damage the device. This study investigated the risk of unintentional valve adjustment associated with the use of game machines in patients with programmable CSF shunt valves. Four adjustable valves from 4 different manufacturers, Sophysa Polaris model SPV (Polaris valve), Miethke proGAV (proGAV), Codman Hakim programmable valve (CHPV), and Strata II small valve (Strata valve), were evaluated. Magnetic field interactions were determined using the portable game machine, Nintendo DS Lite (DS). The maximum distance between the valve and the DS that affected the valve pressure setting was measured by x-ray cinematography. The Polaris valve and proGAV were immune to unintentional reprogramming by the DS. However, the settings of the CHPV and Strata valves were randomly altered by the DS. Patients with an implanted shunt valve should be made aware of the risks posed by the magnetic fields associated with portable game machines and commonly used home electronics. PMID:21946726

  18. Doppler ultrasound evaluation of transjugular intrahepatic portosystemic shunt function: pitfalls and artifacts.

    PubMed

    Wachsberg, Ronald H

    2003-09-01

    The current literature reflects controversy regarding the accuracy of Doppler ultrasound for the detection of transjugular intrahepatic portosystemic shunt (TIPS) malfunction. Experience has revealed many pitfalls and artifacts that can potentially interfere with the proper performance and interpretation of Doppler studies in patients with TIPS. In this article the author discusses and illustrates the spectrum of pitfalls that may be encountered during Doppler evaluation of TIPS function. PMID:14571161

  19. Asymptomatic Intrahepatic Portosystemic Venous Shunt: To Treat or Not To Treat?

    PubMed

    Palvanov, Arkadiy; Marder, Ruth Leah; Siegel, David

    2016-09-01

    Intrahepatic portosystemic venous shunts (IPSVSs) are rare vascular malformations. They can be asymptomatic or present with various symptoms including encephalopathy. We present two cases of IPSVS, one involving a patient presenting with altered mental status and the other discovered incidentally. While there is no question that patients presenting with symptomatic IPSVS should undergo definitive treatment, there is no consensus regarding elective therapy for asymptomatic lesions. PMID:27574389

  20. Embolization of Hepatic Arteriovenous Shunt with Absolute Ethanol in a Patient with Hepatocellular Carcinoma

    SciTech Connect

    Senokuchi, Terutoshi Baba, Yasutaka Hayashi, Sadao Nakajo, Masayuki

    2011-02-15

    We report a 76-year-old man who had hepatocellular carcinoma (HCC) with arteriovenous shunting (AVS). Transcatheter chemoembolization (TACE) was selected as treatment because of poor pulmonary function. To prevent pulmonary embolism caused by the flow of embolic materials through the AVS, we performed embolization of the AVS with absolute ethanol under flow control by balloon catheters. Subsequently, we could perform TACE for HCC safely.

  1. Revisiting the surgical creation of volume load by aorto-caval shunt in rats.

    PubMed

    Ocampo, Catherina; Ingram, Paul; Ilbawi, Michel; Arcilla, Rene; Gupta, Madhu

    2003-09-01

    Cardiac hypertrophy is an early landmark during the clinical course of heart failure, and is an important risk factor for subsequent morbidity and mortality. The hypertrophy response to different types of cardiac overload is distinguished both at the molecular and cellular levels. These changes have been extensively characterized for pressure load hypertrophy; however, similar information for volume load hypertrophy is still needed. This study was undertaken to improve the existing method of producing experimental cardiac volume load. Previous investigators have employed surgical aorto-caval shunt (ACS) as a model for volume load hypertrophy (VO) in rats. The procedure is relatively simple and involves glue to seal the aortic hole after ACS. However, it has several limitations mostly related to the use of glue e.g. poor visualization due to hardening of tissues, imperfect sealing of the puncture site and glue seeping through the aortic hole resulting in shunt occlusion. We have modified the procedure using aortic adventitial suture instead of glue and 18G angiocatheter instead of 16G needle, which eliminated the technical difficulties from the former method. The ACS was visually confirmed at sacrifice, and the VO demonstrated by time-related changes in the heart weight/body weight ratio which increased from 78% at 4 weeks to 87% at 10 weeks and increased liver/body weight ratio by 22% at 10 weeks of post aorto-caval shunt. Cardiac expression of atrial natriuretic peptide (ANF) also demonstrated time-related increase in ANF mRNA (+275% increase at 4 weeks, p < 0.05, and +370% increase at 10 weeks, p < 0.001). This modified technique of aorto-caval shunt offers simpler, reproducible and consistent model for VO hypertrophy in rats.

  2. Asymptomatic Intrahepatic Portosystemic Venous Shunt: To Treat or Not To Treat?

    PubMed

    Palvanov, Arkadiy; Marder, Ruth Leah; Siegel, David

    2016-09-01

    Intrahepatic portosystemic venous shunts (IPSVSs) are rare vascular malformations. They can be asymptomatic or present with various symptoms including encephalopathy. We present two cases of IPSVS, one involving a patient presenting with altered mental status and the other discovered incidentally. While there is no question that patients presenting with symptomatic IPSVS should undergo definitive treatment, there is no consensus regarding elective therapy for asymptomatic lesions.

  3. Usefulness of Transjugular Intrahepatic Portosystemic Shunt in the Management of Bleeding Ectopic Varices in Cirrhotic Patients

    SciTech Connect

    Vidal, V.; Joly, L.; Perreault, P.; Bouchard, L.; Lafortune, M.; Pomier-Layrargues, G.

    2006-04-15

    Purpose. To evaluate the safety and efficacy of transjugular intrahepatic portosystemic shunt (TIPS) in the control of bleeding from ectopic varices. Methods. From 1995 to 2004, 24 cirrhotic patients, bleeding from ectopic varices, mean age 54.5 years (range 15-76 years), were treated by TIPS. The etiology of cirrhosis was alcoholic in 13 patients and nonalcoholic in 11 patients. The location of the varices was duodenal (n = 5), stomal (n = 8), ileocolic (n = 6), anorectal (n = 3), umbilical (n = 1), and peritoneal (n 1). Results. TIPS controlled the bleeding in all patients and induced a decrease in the portacaval gradient from 19.7 {+-} 5.4 to 6.4 {+-} 3.1 mmHg. Postoperative complications included self-limited intra-abdominal bleeding (n = 2), self-limited hemobilia (n = 1), acute thrombosis of the shunt (n = 1), and bile leak treated by a covered stent (n = 1). Median follow-up was 592 days (range 28-2482 days). Rebleeding occurred in 6 patients. In 2 cases rebleeding was observed despite a post-TIPS portacaval gradient lower than 12 mmHg and was controlled by variceal embolization; 1 patient underwent surgical portacaval shunt and never rebled; in 3 patients rebleeding was related to TIPS stenosis and treated with shunt dilatation with addition of a new stent. The cumulative rate of rebleeding was 23% and 31% at 1 and 2 years, respectively. One- and 2-year survival rates were 80% and 76%, respectively. Conclusion. The present series demonstrates that bleeding from ectopic varices, a challenging clinical problem, can be managed safely by TIPS placement with low rebleeding and good survival rates.

  4. Resting pulmonary haemodynamics and shunting: a comparison of sea-level inhabitants to high altitude Sherpas.

    PubMed

    Foster, Glen E; Ainslie, Philip N; Stembridge, Mike; Day, Trevor A; Bakker, Akke; Lucas, Samuel J E; Lewis, Nia C S; MacLeod, David B; Lovering, Andrew T

    2014-03-15

    The incidence of blood flow through intracardiac shunt and intrapulmonary arteriovenous anastomoses (IPAVA) may differ between Sherpas permanently residing at high altitude (HA) and sea-level (SL) inhabitants as a result of evolutionary pressure to improve gas exchange and/or resting pulmonary haemodynamics. To test this hypothesis we compared sea-level inhabitants at SL (SL-SL; n = 17), during acute isocapnic hypoxia (SL-HX; n = 7) and following 3 weeks at 5050 m (SL-HA; n = 8 non-PFO subjects) to Sherpas at 5050 m (n = 14). SpO2, heart rate, pulmonary artery systolic pressure (PASP) and cardiac index (Qi) were measured during 5 min of room air breathing at SL and HA, during 20 min of isocapnic hypoxia (SL-HX; PETO2 = 47 mmHg) and during 5 min of hyperoxia (FIO2 = 1.0; Sherpas only). Intracardiac shunt and IPAVA blood flow was evaluated by agitated saline contrast echocardiography. Although PASP was similar between groups at HA (Sherpas: 30.0 ± 6.0 mmHg; SL-HA: 32.7 ± 4.2 mmHg; P = 0.27), it was greater than SL-SL (19.4 ± 2.1 mmHg; P < 0.001). The proportion of subjects with intracardiac shunt was similar between groups (SL-SL: 41%; Sherpas: 50%). In the remaining subjects, IPAVA blood flow was found in 100% of subjects during acute isocapnic hypoxia at SL, but in only 4 of 7 Sherpas and 1 of 8 SL-HA subjects at rest. In conclusion, differences in resting pulmonary vascular regulation, intracardiac shunt and IPAVA blood flow do not appear to account for any adaptation to HA in Sherpas. Despite elevated pulmonary pressures and profound hypoxaemia, IPAVA blood flow in all subjects at HA was lower than expected compared to acute normobaric hypoxia.

  5. From shunting inhibition to dynamic normalization: Attentional selection and decision-making in brief visual displays.

    PubMed

    Smith, Philip L; Sewell, David K; Lilburn, Simon D

    2015-11-01

    Normalization models of visual sensitivity assume that the response of a visual mechanism is scaled divisively by the sum of the activity in the excitatory and inhibitory mechanisms in its neighborhood. Normalization models of attention assume that the weighting of excitatory and inhibitory mechanisms is modulated by attention. Such models have provided explanations of the effects of attention in both behavioral and single-cell recording studies. We show how normalization models can be obtained as the asymptotic solutions of shunting differential equations, in which stimulus inputs and the activity in the mechanism control growth rates multiplicatively rather than additively. The value of the shunting equation approach is that it characterizes the entire time course of the response, not just its asymptotic strength. We describe two models of attention based on shunting dynamics, the integrated system model of Smith and Ratcliff (2009) and the competitive interaction theory of Smith and Sewell (2013). These models assume that attention, stimulus salience, and the observer's strategy for the task jointly determine the selection of stimuli into visual short-term memory (VSTM) and the way in which stimulus representations are weighted. The quality of the VSTM representation determines the speed and accuracy of the decision. The models provide a unified account of a variety of attentional phenomena found in psychophysical tasks using single-element and multi-element displays. Our results show the generality and utility of the normalization approach to modeling attention.

  6. Facial diplegia revealing ventriculoperitoneal shunt failure in a patient with Crouzon syndrome. Case report.

    PubMed

    Thines, Laurent; Vinchon, Matthieu; Lahlou, Amine; Pellerin, Philippe; Dhellemmes, Patrick

    2007-07-01

    The authors report on the case of a 15-year-old boy with Crouzon syndrome (CS) who presented with headache and facial diplegia. He had undergone several craniofacial interventions and a posterior fossa decompression for tonsillar herniation caused by the CS. A ventriculoperitoneal (VP) shunt had been inserted for hydrocephalus. Emergency computed tomography (CT) disclosed slight dilation of the ventricular cavities compared with their appearance on a baseline CT scan. Magnetic resonance imaging showed a deformed brainstem but no compression at the occipital foramen; there was no apparent explanation for the facial diplegia. The neuroophthalmological examination revealed neither papilledema nor oculomotor palsy. Electromyography confirmed incomplete peripheral facial diplegia. The patient underwent emergency shunt revision, during which complete obstruction of the ventricular catheter and severe cerebrospinal fluid hypertension were found. After surgery, cranial hypertension symptoms completely resolved and the facial diplegia improved slowly with a persistent and incomplete right superior facial palsy. Cranial 3D CT scanning reconstructions and brain magnetic resonance imaging demonstrated severe petrous bone distortion that could have been responsible for direct stretching injuries on the facial nerves at the level of the internal acoustic meatus. The present case represents the first reported occurrence of VP shunt failure as revealed by a facial palsy; the authors discuss the pathophysiology of facial palsy in intracranial hypertension.

  7. Gender and diurnal effects on specific open-field behavioral patterns in the portacaval shunted rat.

    PubMed

    Theander, B; Apelqvist, G; Bugge, M; Andersson, G; Hindfelt, B; Bengtsson, F

    1997-03-01

    Hepatic encephalopathy (HE) is a frequently observed neuropsychiatric syndrome with unknown pathogenesis in patients suffering from chronic liver failure. The portacaval shunted (PCS) rat has been extensively used as an experimental model for HE and for studying the effects of portal-systemic shunting. Previous behavioral studies on PCS rats have shown a number of abnormalities but there is no consensus about which abnormalities are characteristic. We therefore made a thorough descriptive study of 100 male and female PCS rats and sham-operated controls four to six weeks after the shunting procedure in an open field. The frequency, duration and average time sequence of various kinds of defined spontaneous behavioral patterns were investigated during both night and day in order to assess behavioral differences between PCS rats and sham-operated controls. The results indicate differences especially regarding motor exploratory behaviors such as forward locomotion and rearing. There were also differences in eating and sniffing behaviors. Our results show that the overall behavioral alteration seen in PCS rats compared to sham-operated controls is that of hypoactivity.

  8. Comparative Flow Dynamics in Two In Vitro Models of an Adjustable Systemic-Pulmonary Artery Shunt

    NASA Astrophysics Data System (ADS)

    Brown, Tim; Bates, Nathan; Douglas, William; Knapp, Charles; Jacob, Jamey

    2002-11-01

    Systemic-pulmonary artery (SPA) shunts are connections that exist to augment pulmonary blood flow in neonates born with single ventricle physiology. An appropriate balance between the systemic and pulmonary circulations is crucial to their survival. To achieve this, an adjustable SPA shunt is being developed at our institution that consists of a 4 mm PTFE tube with a screw plunger mechanism to achieve the desired change in flow rate by increasing pulmonary resistance. To determine the effect this mechanism has on flow patterns, two in vitro models were created; an idealized model with an axisymmetric constriction and a model developed from flow phantoms of the actual shunt under various actuations. These models were used to measure the instantaneous velocity and vorticity fields using PIV. Recirculation regions downstream of the constriction were observed for both models. For the idealized model, a separation region persisted for approximately 2-5 diameters downstream with a flow range between 600-850 cc/min, corresponding to in vivo conditions and a Re of approximately 1000-1500. In the realistic test sections, shedding vortices were visible 2.5 diameters downstream on the opposing side of the imposed constriction. The flow field structure and wall skin friction of the two cases under various conditions will be discussed.

  9. Accurate expressions for solar cell fill factors including series and shunt resistances

    NASA Astrophysics Data System (ADS)

    Green, Martin A.

    2016-02-01

    Together with open-circuit voltage and short-circuit current, fill factor is a key solar cell parameter. In their classic paper on limiting efficiency, Shockley and Queisser first investigated this factor's analytical properties showing, for ideal cells, it could be expressed implicitly in terms of the maximum power point voltage. Subsequently, fill factors usually have been calculated iteratively from such implicit expressions or from analytical approximations. In the absence of detrimental series and shunt resistances, analytical fill factor expressions have recently been published in terms of the Lambert W function available in most mathematical computing software. Using a recently identified perturbative relationship, exact expressions in terms of this function are derived in technically interesting cases when both series and shunt resistances are present but have limited impact, allowing a better understanding of their effect individually and in combination. Approximate expressions for arbitrary shunt and series resistances are then deduced, which are significantly more accurate than any previously published. A method based on the insights developed is also reported for deducing one-diode fits to experimental data.

  10. The adjustable systemic-pulmonary artery shunt provides precise control of flow in vivo.

    PubMed

    Douglas, William I; Moore, Karabeth B; Resig, Phillip P; Mohiuddin, M Waqar

    2010-01-01

    The ratio of pulmonary:systemic blood flow (Qp:Qs) remains problematic after single ventricle reconstruction. The adjustable systemic-pulmonary artery shunt (AS) was created as a solution for this problem. Prototype ASs were created using a screw-plunger mechanism as a variable resistor. A stepper motor controls plunger displacement. Six adult dogs underwent placement of a 4-mm AS in the femoral position to test its ability to control flow. Shunts were placed as arteriovenous fistulae to simulate the continuous flow of systemic-pulmonary AS. The 3.5-mm control shunts (CS) were placed on the contralateral side. The stepper motor was rotated from fully open to 3.4 mm of plunger depression for six complete cycles. Flow in the fully open AS was 687.9 +/- 28.7 cc/min* vs. 578.7 +/- 26.8 cc/min in the CS (flow +/- standard error, *p < 0.005 vs. CS). Standard deviation of flow was similar between the AS and CS, implying hysteresis in resistor function did not contribute to flow variability. Peak torque requirement to turn the resistor was 2.4 mNm. The AS offers excellent control of flow in vivo. Control of Qp:Qs may lead to improved outcomes for single ventricle reconstructions. PMID:20051834

  11. Simultaneous Cranioplasty and Subdural-Peritoneal Shunting for Contralateral Symptomatic Subdural Hygroma following Decompressive Craniectomy

    PubMed Central

    Lin, Muh-Shi; Chen, Tzu-Hsuan; Kung, Woon-Man; Chen, Shuo-Tsung

    2015-01-01

    Background. Contralateral subdural hygroma caused by decompressive craniectomy tends to combine with external cerebral herniation, causing neurological deficits. Material and Methods. Nine patients who underwent one-stage, simultaneous cranioplasty and contralateral subdural-peritoneal shunting were included in this study. Clinical outcome was assessed by Glasgow Outcome Scale as well as Glasgow Coma Scale, muscle power scoring system, and complications. Results. Postoperative computed tomography scans demonstrated completely resolved subdural hygroma and reversed midline shifts, indicating excellent outcome. Among these 9 patients, 4 patients (44%) had improved GOS following the proposed surgery. Four out of 4 patients with lethargy became alert and orientated following surgical intervention. Muscle strength improved significantly 5 months after surgery in 7 out of 7 patients with weakness. Two out of 9 patients presented with drowsiness due to hydrocephalus at an average time of 65 days after surgery. Double gradient shunting is useful to eliminate the respective hydrocephalus and contralateral subdural hygroma. Conclusion. The described surgical technique is effective in treating symptomatic contralateral subdural hygroma following decompressive craniectomy and is associated with an excellent structural and functional outcome. However, subdural-peritoneal shunting plus cranioplasty thoroughly resolves the subdural hygroma collection, which might deteriorate the cerebrospinal fluid circulation, leading to hydrocephalus. PMID:25879062

  12. Homeostasis and the glycogen shunt explains aerobic ethanol production in yeast.

    PubMed

    Shulman, Robert G; Rothman, Douglas L

    2015-09-01

    Aerobic glycolysis in yeast and cancer cells produces pyruvate beyond oxidative needs, a paradox noted by Warburg almost a century ago. To address this question, we reanalyzed extensive measurements from (13)C magnetic resonance spectroscopy of yeast glycolysis and the coupled pathways of futile cycling and glycogen and trehalose synthesis (which we refer to as the glycogen shunt). When yeast are given a large glucose load under aerobic conditions, the fluxes of these pathways adapt to maintain homeostasis of glycolytic intermediates and ATP. The glycogen shunt uses glycolytic ATP to store glycolytic intermediates as glycogen and trehalose, generating pyruvate and ethanol as byproducts. This conclusion is supported by studies of yeast with a partial block in the glycogen shunt due to the cif mutation, which found that when challenged with glucose, the yeast cells accumulate glycolytic intermediates and ATP, which ultimately leads to cell death. The control of the relative fluxes, which is critical to maintain homeostasis, is most likely exerted by the enzymes pyruvate kinase and fructose bisphosphatase. The kinetic properties of yeast PK and mammalian PKM2, the isoform found in cancer, are similar, suggesting that the same mechanism may exist in cancer cells, which, under these conditions, could explain their excess lactate generation. The general principle that homeostasis of metabolite and ATP concentrations is a critical requirement for metabolic function suggests that enzymes and pathways that perform this critical role could be effective drug targets in cancer and other diseases.

  13. What is the ideal initial valve pressure setting in neonates with ventriculoperitoneal shunts?

    PubMed

    Korinth, Marcus C; Gilsbach, J M

    2002-04-01

    In order to determine the optimal valve pressure setting during the first weeks in neonates after implantation of programmable Hakim valves and to analyze the benefits and possible side effects of a new treatment protocol in this age group, we performed this prospective study. In 20 consecutive newborns less than 5 weeks of age with hydrocephalus due to various etiologies, a ventriculoperitoneal shunt with a programmable Hakim valve at an extremely low initial valve pressure setting of 30-40 mm H(2)O was implanted. This "overdrainage" was maintained, monitored by regular clinical examination and transcranial ultrasonographic imaging, until the wound healing was uneventfully completed and the permanent valve pressure setting of 100-120 mm H(2)O was chosen. In this age group, which is prone to specific noninfectious shunt complications like wound breakdown, cerebrospinal fluid (CSF) fistula and subcutaneous CSF collections, none of these complications were seen, nor were there any persisting overdrainage phenomena on transcranial ultrasonography. Initial, temporary "overdrainage" represents a simple, useful and risk-free therapy in neonates with programmable shunts which might lower the incidence of typical noninfectious complications in this age group. PMID:12006750

  14. Dual-Functional Energy-Harvesting and Vibration Control: Electromagnetic Resonant Shunt Series Tuned Mass Dampers.

    PubMed

    Zuo, Lei; Cui, Wen

    2013-10-01

    This paper proposes a novel retrofittable approach for dual-functional energy-harvesting and robust vibration control by integrating the tuned mass damper (TMD) and electromagnetic shunted resonant damping. The viscous dissipative element between the TMD and primary system is replaced by an electromagnetic transducer shunted with a resonant RLC circuit. An efficient gradient based numeric method is presented for the parameter optimization in the control framework for vibration suppression and energy harvesting. A case study is performed based on the Taipei 101 TMD. It is found that by tuning the TMD resonance and circuit resonance close to that of the primary structure, the electromagnetic resonant-shunt TMD achieves the enhanced effectiveness and robustness of double-mass series TMDs, without suffering from the significantly amplified motion stroke. It is also observed that the parameters and performances optimized for vibration suppression are close to those optimized for energy harvesting, and the performance is not sensitive to the resistance of the charging circuit or electrical load.

  15. Dual-Functional Energy-Harvesting and Vibration Control: Electromagnetic Resonant Shunt Series Tuned Mass Dampers.

    PubMed

    Zuo, Lei; Cui, Wen

    2013-10-01

    This paper proposes a novel retrofittable approach for dual-functional energy-harvesting and robust vibration control by integrating the tuned mass damper (TMD) and electromagnetic shunted resonant damping. The viscous dissipative element between the TMD and primary system is replaced by an electromagnetic transducer shunted with a resonant RLC circuit. An efficient gradient based numeric method is presented for the parameter optimization in the control framework for vibration suppression and energy harvesting. A case study is performed based on the Taipei 101 TMD. It is found that by tuning the TMD resonance and circuit resonance close to that of the primary structure, the electromagnetic resonant-shunt TMD achieves the enhanced effectiveness and robustness of double-mass series TMDs, without suffering from the significantly amplified motion stroke. It is also observed that the parameters and performances optimized for vibration suppression are close to those optimized for energy harvesting, and the performance is not sensitive to the resistance of the charging circuit or electrical load. PMID:23918165

  16. Portosystemic shunting in portal hypertension: evaluation with portal scintigraphy with transrectally administered I-123 IMP

    SciTech Connect

    Kashiwagi, T.; Azuma, M.; Ikawa, T.; Takehara, T.; Matsuda, H.; Yoshioka, H.; Mitsutani, N.; Koizumi, T.; Kimura, K.

    1988-10-01

    Portosystemic shunting was evaluated with rectal administration of iodine-123 iodoamphetamine (IMP) in seven patients without liver disease and 53 patients with liver cirrhosis. IMP (2-3 mCi (74-111 MBq)) was administered to the rectum through a catheter. Images of the chest and abdomen were obtained for up to 60 minutes with a scintillation camera interfaced with a computer. In all patients, images of the liver and/or lungs were observed within 5-10 minutes and became clear with time. In patients without liver disease, only liver images could be obtained, whereas the lung was visualized with or without the liver in all patients with liver cirrhosis. The portosystemic shunt index was calculated by dividing counts of lungs by counts of liver and lung. These values were significantly higher in liver cirrhosis, especially in the decompensated stage. Transrectal portal scintigraphy with IMP appears to be a useful method for noninvasive and quantitative evaluation of portosystemic shunting in portal hypertension.

  17. Evaluation of peritoneovenous shunt patency with Tc-99m labeled microspheres.

    PubMed

    Madeddu, G; D'Ovidio, N G; Casu, A R; Mura, R; Costanza, C; Lai, N; LeVeen, H H

    1983-04-01

    The LeVeen peritoneovenous shunt (PVS) was investigated in 40 cirrhotic patients with refractory ascites. Five millicuries of Tc-99m-tagged human albumin microspheres (15-36 microns) were injected into the peritoneal cavity between the umbilicus and the left anterior superior iliac spine. The radiotracer was always detectable by scintigram in the lungs when the shunt was patent. In case of malfunction, by contrast, the radioactivity was either restricted to the venous tube or confined below the diaphragm for at least 4 hr. In the presence of complete obstruction, whereas the tube was not visualized after peritoneal injection, it was outlined by direct injection of 2 mCi of Tc-99m albumin microspheres into its subcutaneous tract, where it crossed the 12th rib, immediately above the valve. This technique sufficed to establish whether the site of obstruction was at the valve or in the tubing itself. In one patient, poor visualization of the tube and a delayed image of the lungs was caused by partial occlusion of the valve with fibrinoid debris. This radiotracer method proved simple, quick, and led to an immediate selective replacement when the shunt was not patent. Therefore, the use of this test is recommended for a definitive diagnosis, since there were neither false negatives nor false positives. No complications such as embolism or bacterial infection were encountered with Tc-99m human albumin microspheres, which are excellent tracers. PMID:6220137

  18. Homeostasis and the glycogen shunt explains aerobic ethanol production in yeast

    PubMed Central

    Shulman, Robert G.; Rothman, Douglas L.

    2015-01-01

    Aerobic glycolysis in yeast and cancer cells produces pyruvate beyond oxidative needs, a paradox noted by Warburg almost a century ago. To address this question, we reanalyzed extensive measurements from 13C magnetic resonance spectroscopy of yeast glycolysis and the coupled pathways of futile cycling and glycogen and trehalose synthesis (which we refer to as the glycogen shunt). When yeast are given a large glucose load under aerobic conditions, the fluxes of these pathways adapt to maintain homeostasis of glycolytic intermediates and ATP. The glycogen shunt uses glycolytic ATP to store glycolytic intermediates as glycogen and trehalose, generating pyruvate and ethanol as byproducts. This conclusion is supported by studies of yeast with a partial block in the glycogen shunt due to the cif mutation, which found that when challenged with glucose, the yeast cells accumulate glycolytic intermediates and ATP, which ultimately leads to cell death. The control of the relative fluxes, which is critical to maintain homeostasis, is most likely exerted by the enzymes pyruvate kinase and fructose bisphosphatase. The kinetic properties of yeast PK and mammalian PKM2, the isoform found in cancer, are similar, suggesting that the same mechanism may exist in cancer cells, which, under these conditions, could explain their excess lactate generation. The general principle that homeostasis of metabolite and ATP concentrations is a critical requirement for metabolic function suggests that enzymes and pathways that perform this critical role could be effective drug targets in cancer and other diseases. PMID:26283370

  19. Development of a nonintermediate-incision ventriculoperitoneal shunt procedure using a nasogastric feeding tube for infant patients with hydrocephalus: technical note.

    PubMed

    Hamauchi, Shuji; Seki, Toshitaka; Sasamori, Toru; Houkin, Kiyohiro

    2016-05-01

    Intermediate incisions are considered necessary to pass a catheter tube from the head to the abdomen in ventriculo-peritoneal (VP) shunting via a frontal bur hole. However, an intermediate incision can sometimes become dehiscent, resulting in CSF leakage or infection of the shunt system in the early period after shunt implantation, particularly in infant patients. In this article, the authors describe a novel method of VP shunt insertion that does not require an intermediate incision. This nonintermediate-incision VP shunt procedure was performed in 3 infant patients with hydrocephalus and was not associated with any complications. This method can eliminate the intermediate incision, which is a disadvantage of VP shunt insertion via a frontal bur hole.

  20. Comparison of shunt fraction estimation using transcolonic iodine-123-iodoamphetamine and technetium-99m-pertechnetate in a group of dogs with experimentally-induced chronic biliary cirrhosis

    SciTech Connect

    Koblik, P.D.; Hornof, W.J.; Yen, C.K.; Komtebedde, J.; Breznock, E.; Fisher, P. )

    1991-01-01

    Portosystemic shunt fraction estimation using transcolonic iodine-123-iodoamphetamine (IMP) has been previously validated relative to portal vein macroaggregated albumin injections using an experimental model of cirrhosis. Transcolonic technetium-99m-pertechnetate (TcO4-) has been proposed as an alternative tracer to IMP to study portal circulation in cirrhotic patients. We compared shunt fraction estimates from paired transcolonic IMP and TcO4- studies performed on a group of dogs before and after common bile duct ligation surgery. Pertechnetate over-estimated shunt fraction in 6/7 postoperative studies relative to IMP. A good correlation between the two methods was demonstrated, however, the slope of the regression line was substantially less than 1.0 with TcO4- values reaching 100% at IMP shunt values of approximately 60%. This apparent inability to accurately assess high shunt flows may limit the quantitative aspects of TcO4- studies on patients with severe portosystemic shunting.