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Sample records for lumbar apophyseal ring

  1. A posterior ring apophyseal fracture and disc herniation in a 21-year-old competitive basketball player: a case report

    PubMed Central

    Deleo, Trevor; Merotto, Samuel; Smith, Colyn; D’Angelo, Kevin

    2015-01-01

    Objective: To describe the diagnosis and management of a competitive male basketball player with discogenic low back pain and presence of an old posterior ring apophyseal fracture (PRAF). This case will highlight the importance of early recognition and considerations regarding patient management for this differential of radiating low back pain. Clinical Features: A 21-year-old provincial basketball player presented with recurrent radiating low back pain into the left groin and lower limb. After several weeks of persistent symptoms including pain, muscle weakness, and changes in the Achilles deep tendon reflex, imaging was obtained that revealed a large disc extrusion with an old posterior ring apophyseal fracture. In collaboration with a spine surgeon and family physician, the patient was treated using a conservative, multimodal approach. Treatment consisted of graded mobilizations, spinal manipulative therapy, interferential current, and soft tissue therapy to the lumbar spine. Rehabilitation exercises focused on centralizing symptoms and improving strength, proprioception and function of the lower limb. After a period of 8 weeks, the patient was able to complete all activities of daily living without pain in addition to returning to basketball practice. Summary: PRAF is a unique condition in the immature spine and recent evidence suggests that those involved in sports requiring repetitive motion of the lumbar spine may be at increased risk. The astute clinician must consider this differential in young populations presenting with discogenic low back pain, as a timely diagnosis and necessary referral may allow for effective conservative management to reduce symptoms. Equally as important, one must be aware of the complications from PRAF as a contributing source of low back pain and dysfunction into adulthood. Knowing when to refer for advanced imaging and/or a surgical consult given the variable clinical presentation and prognosis is an essential component to care

  2. Calcaneal apophysitis due to brucellosis.

    PubMed

    Ozgocmen, Salih; Kocakoc, Ercan; Kiris, Adem; Sen, Yasar; Ardicoğlu, Ozge

    2003-02-01

    Brucellosis is still a major health problem in many geographical areas. Osteoarticular complications are important owing to their high prevalence. We report an unusual case of childhood brucellosis presenting with septic apophysitis of the calcaneus and abscess formation in a 12-year-old boy. The patient was successfully treated with a combination of antibiotics. The importance of early recognition of the disease and differential diagnosis is emphasized. Early recognition of infection, prolonged treatment, and long-term follow-up may improve the outcome.

  3. Greater trochanter apophysitis in the adolescent athlete.

    PubMed

    Young, Simon W; Safran, Marc R

    2015-05-01

    Lower limb traction apophysitis is common in young athletes, occurring at sites such as the tibial tubercle (Osgood-Schlatter disease) and distal patella (Sinding-Larsen-Johansson disease). Around the hip, iliac apophysitis is well recognized, but no cases of greater trochanter apophysitis have previously been reported. We describe the case of a 15-year-old male basketball player with a 2-month history of the right hip pain and significant functional limitation. X-rays revealed widening of the greater trochanter apophysis with subchondral sclerosis, consistent with a diagnosis of traction apophysitis. The patient was treated with a period of relative rest and anti-inflammatory medication. He gradually returned to full athletic activity, including basketball, without recurrence of pain or limitation. We describe the first reported case of traction apophysitis of the greater trochanter. The unique muscular anatomy of this apophysis with balanced forces explains the rarity of this condition. If encountered, rest and activity modification is the recommended treatment.

  4. [Bilateral hyperplasia of the coronoid apophyses. A clinical case].

    PubMed

    Parascandolo, S; Rusciano, A; Tamai, M; Morlino, M

    1993-03-01

    The authors report on the case of a young patient affected with bilateral hyperplasia of the coronoid apophyses, who presented a serious reduction of the mandibular excursion. Normal mouth opening was re-established by a bilateral osteotomy with endoral removal of the coronoid apophyses.

  5. Ischial apophyseal fracture in an abused infant.

    PubMed

    Bixby, Sarah D; Wilson, Celeste R; Barber, Ignasi; Kleinman, Paul K

    2014-09-01

    We report a previously healthy 4-month-old who presented to the hospital with leg pain and swelling and no history of trauma. Radiographs demonstrated a comminuted left femur fracture. Given the concern for child abuse, skeletal survey was performed and revealed four vertebral compression deformities. Although abuse was suspected, the possibility of a lytic lesion associated with the femur fracture and multiple spinal abnormalities raised the possibility of an underlying process such as Langerhans cell histiocytosis. Subsequently 18F-NaF positron emission tomographic (PET) scintigraphy revealed increased tracer activity in the ischium, and MRI confirmed an ischial apophyseal fracture. Pelvic fractures, particularly ischial fractures, are extremely rare in the setting of child abuse. This case report describes the multimodality imaging findings of an ischial fracture in an abused infant.

  6. [Macroscopic and functional anatomy of the apophyseal plate].

    PubMed

    Putz, R; Milz, S

    2016-03-01

    Apophyses are growth zones attached to the shaft (corpus) of larger bones. They vary in size and develop their own ossification centres or form as part of an usually fibrocartilaginous tendon or ligament insertion. The structure of the cartilaginous apophyseal plate is very similar to that of an epiphyseal growth plate and like these they are adapted to withstand perpendicular compressive forces without becoming harmed. This is best highlighted by the fact that their mineralized borders always orient themselves perpendicular to the overall resulting force vector. The edges of the apophyseal plates are characteristically bent which allows them to resist moderate shear forces. Like the epiphyseal plates the apophyseal plates exhibit a zonal organization which is not very well adapted to permanently withstand shear forces, especially if they occur under dynamic conditions. In these situations the tendinous insertions with their collagen fibre anchoring system have to provide compensation when balancing the load transmitted across the system.

  7. [Apophyseal avulsions of the pelvis and proximal femur].

    PubMed

    Jacobsen, S

    1993-07-05

    Avulsion fractures of the pelvic and proximal femoral apophyseal centres are not uncommonly seen in adolescent athletes engaged in vigorous sports. They are the result of strong or uncoordinated muscular traction, and are the equivalents of muscle or tendon pulls in mature athletes. They are particularly seen in athletics, soccer, rugby, ice hockey and break dance. They involve the anterior third of the iliac crest, the anterior iliac spines, the tuber ischiadicum, the symphysis pubis and the trochanter minor. The radiographic and clinical diagnosis, symptoms and signs, treatment and prognosis are well described in the orthopaedic literature and this literature is evaluated here. The fractures are easily and almost exclusively treated conservatively, and will only in a few cases result in a lasting functional disability.

  8. Three-Dimensional Analysis of a Ballet Dancer with Ischial Tuberosity Apophysitis. A Case Study

    PubMed Central

    Pohjola, Hanna; Sayers, Mark; Mellifont, Rebecca; Mellifont, Daniel; Venojärvi, Mika

    2014-01-01

    The purpose of this case study was to describe the three-dimensional biomechanics of common ballet exercises in a ballet dancer with ischial tuberosity apophysitis. This was achieved by comparing kinematics between the symptomatic (i.e. ischial apophyseal symptoms) and contralateral lower limbs, as well as via reported pain. Results suggest consistent differences in movement patterns in this dancer. These differences included: 1) decreased external rotation of contralateral hip, hence a decreased hip contribution to ‘turn out’; 2) increased contralateral knee adduction and internal rotation; 3) an apparent synchronicity in the contralateral lower limb of the decreased hip external rotation and increased knee adduction; and 4) minimal use of ankle plantar/dorsiflexion movement for symptomatic side. Pain related to the left ischial apophysitis was associated with reduced amplitudes especially in fast ballet movements that required large range of motion in flexion and adduction in the left hip joint. These findings suggest that ischial apophysitis may limit dancer’s ballet technique and performance. Key Points The pain related to the left ischial apophysitis was associated with reduced amplitudes especially in fast ballet movements that require large range of motion. This may affect to the lower limbs kinematics, and limit dancer’s technique and performance. Compensatory strategies in the kinetic chain, differences in the joint angles between the lower limbs, traction forces, velocity and amplitude demands should be taken in consideration while training and rehabilitation of the ischial apophyseal injury within classical ballet. PMID:25435780

  9. Three-dimensional analysis of a ballet dancer with ischial tuberosity apophysitis. A case study.

    PubMed

    Pohjola, Hanna; Sayers, Mark; Mellifont, Rebecca; Mellifont, Daniel; Venojärvi, Mika

    2014-12-01

    The purpose of this case study was to describe the three-dimensional biomechanics of common ballet exercises in a ballet dancer with ischial tuberosity apophysitis. This was achieved by comparing kinematics between the symptomatic (i.e. ischial apophyseal symptoms) and contralateral lower limbs, as well as via reported pain. Results suggest consistent differences in movement patterns in this dancer. These differences included: 1) decreased external rotation of contralateral hip, hence a decreased hip contribution to 'turn out'; 2) increased contralateral knee adduction and internal rotation; 3) an apparent synchronicity in the contralateral lower limb of the decreased hip external rotation and increased knee adduction; and 4) minimal use of ankle plantar/dorsiflexion movement for symptomatic side. Pain related to the left ischial apophysitis was associated with reduced amplitudes especially in fast ballet movements that required large range of motion in flexion and adduction in the left hip joint. These findings suggest that ischial apophysitis may limit dancer's ballet technique and performance. Key PointsThe pain related to the left ischial apophysitis was associated with reduced amplitudes especially in fast ballet movements that require large range of motion. This may affect to the lower limbs kinematics, and limit dancer's technique and performance.Compensatory strategies in the kinetic chain, differences in the joint angles between the lower limbs, traction forces, velocity and amplitude demands should be taken in consideration while training and rehabilitation of the ischial apophyseal injury within classical ballet.

  10. McKenzie treatment versus mulligan sustained natural apophyseal glides for chronic mechanical low back pain

    PubMed Central

    Waqqar, Saira; Shakil-ur-Rehman, Syed; Ahmad, Shakeel

    2016-01-01

    Background and Objective: Chronic mechanical low back pain is common among different age groups and genders. Different manual therapy techniques combined with exercise therapy and electrotherapy modalities play an important role in its management. Our objective was to compare the effects of McKenzie extension exercisesprogram (EEP) versus Mulligan Sustained Natural Apophyseal Glides (SNAGs) for chronic mechanical low back pain (CMLBP). Methods: This randomized control trial (RCT) was conducted at Riphah Physical Rehabilitation Centre, Pakistan Railways General Hospital Rawalpindi, from 1st July to 31st December 2014. The inclusion criteria was patients of both gender and age range 30-70 years with minimum 4 weeks history of CMLBP. A total of 37 patients were screened out as per inclusion criteria and randomly placed into two groups. Twenty patients in group A were treated with Mulligan SNAGs and 17 patients in group B with McKenzie EEP for four weeks at two session per week and single session per day. Visual Analogue Scale (VAS), Oswestry Disability Scale (ODI) and lumber Range of Motion (ROM) were used as an assessment tools and were measured at baseline and at the completion 4 weeks intervention. The data was analyzed with SPSS to draw the statistical and clinical significance of both interventions. Results: At the completion of 4 weeks intervention the pre and post statistical analysis revealed that clinically the McKenzie EEP improved pain (mean 9.12 to 1.46) and disability (73.82 to 6.24) slightly more than Mulligan SNAGs (pain: from 8.85 to 2.55, disability 73.75 to 7.05), while the Mulligan SNAGs improved lumbar ROM more effectively than McKenzie EEP in all directions including flexion, extension, side bending and rotation. Statistically there was no significant difference between the effects of two interventions in managing pain and disability, and improving Lumber ROM. Conclusion: McKenzie EEP is clinically slightly more effective in the management of pain

  11. Pubic apophysitis: a previously undescribed clinical entity of groin pain in athletes

    PubMed Central

    Sailly, Matthieu; Whiteley, Rod; Read, John W; Giuffre, Bruno; Johnson, Amanda; Hölmich, Per

    2015-01-01

    Background Sport-related pubalgia is often a diagnostic challenge in elite athletes. While scientific attention has focused on adults, there is little data on adolescents. Cadaveric and imaging studies identify a secondary ossification centre located along the anteromedial corner of pubis beneath the insertions of symphysial joint capsule and adductor longus tendon. Little is known about this apophysis and its response to chronic stress. Aim We report pubic apophysitis as a clinically relevant entity in adolescent athletes. Methods The clinical and imaging findings in 26 highly trained adolescent football players (15.6 years±1.3) who complained of adductor-related groin pain were reviewed. The imaging features (X-ray 26/26, US 9/26, MRI 11/26, CT 7/26) of the pubic apophyses in this symptomatic group were compared against those of a comparison group of 31 male patients (age range 9–30 years) with no known history of groin pain or pelvic trauma, who underwent pelvic CT scans for unrelated medical reasons. Results All symptomatic subjects presented with similar history and physical findings. The CT scans of these patients demonstrated open pubic apophyses with stress-related physeal changes (widening, asymmetry and small rounded cyst-like expansions) that were not observed in the comparison group. No comparison subject demonstrated apophyseal maturity before 21 years of age, and immaturity was seen up to the age of 26 years. Conclusions This retrospective case series identifies pubic apophyseal stress (or ‘apophysitis’) as an important differential consideration in the adolescent athlete who presents with groin pain. PMID:26031648

  12. Spinous process apophysitis: a cause of low back pain following repetitive hyperextension in an adolescent female dancer.

    PubMed

    Quinlan, Erin; Reinke, Tari; Bogar, William C

    2013-12-01

    We report a case of a 13-year-old female dancer with spinous process apophysitis following repetitive microtrauma during end-range hyperextension movements. Following appropriate rest and limitation of hyperextension, she was able to return to her previous level of training. It is important to recognize that numerous diagnostic possibilities arise when presented with a young dancer with back pain. The intention of this case report is to compare and contrast the pertinent clinical and radiologic findings of spinous process apophysitis and its more common and debilitating mimic, spondylolysis. The correct diagnosis is paramount in cases of this sort due to the variable treatment requirements of each disorder.

  13. Lumbar spine CT scan

    MedlinePlus

    CAT scan - lumbar spine; Computed axial tomography scan - lumbar spine; Computed tomography scan - lumbar spine; CT - lower back ... stopping.) A computer creates separate images of the spine area, called slices. These images can be stored, ...

  14. The relationship of calcaneal apophyseal ossification and Sanders hand scores to the timing of peak height velocity in adolescents.

    PubMed

    Nicholson, A D; Sanders, J O; Liu, R W; Cooperman, D R

    2015-12-01

    The accurate assessment of skeletal maturity is essential in the management of orthopaedic conditions in the growing child. In order to identify the time of peak height velocity (PHV) in adolescents, two systems for assessing skeletal maturity have been described recently; the calcaneal apophyseal ossification method and the Sanders hand scores. The purpose of this study was to compare these methods in assessing skeletal maturity relative to PHV. We studied the radiographs of a historical group of 94 healthy children (49 females and 45 males), who had been followed longitudinally between the ages of three and 18 years with serial radiographs and physical examination. Radiographs of the foot and hand were undertaken in these children at least annually between the ages of ten and 15 years. We reviewed 738 radiographs of the foot and 694 radiographs of the hand. PHV was calculated from measurements of height taken at the time of the radiographs. Prior to PHV we observed four of six stages of calcaneal apophyseal ossification and two of eight Sanders stages. Calcaneal stage 3 and Sanders stage 2 was seen to occur about 0.9 years before PHV, while calcaneal stage 4 and Sanders stage 3 occurred approximately 0.5 years after PHV. The stages of the calcaneal and Sanders systems can be used in combination, offering better assessment of skeletal maturity with respect to PHV than either system alone.

  15. “Effectiveness of interventions in reducing pain and maintaining physical activity in children and adolescents with calcaneal apophysitis (Sever’s disease): a systematic review”

    PubMed Central

    2013-01-01

    Background Calcaneal apophysitis, also commonly known as sever’s disease, is a condition seen in children usually aged between 8–15 years. Conservative therapies, such as taping, heel lifts and orthotic intervention are accepted management practices for calcaneal apophysitis, though there is very little high quality research examining the efficacy of such treatment modalities. Previous narrative literature reviews and opinion pieces provide some evidence for the use of heel raises or orthoses. The aim of this manuscript was to complete a systemic review on the treatment options for calcaneal apophysitis as measured by pain reduction and maintenance of physical activity. Methods A search strategy completed by two reviewers examined nine databases from inception to May 2012. Search terms included heel pain, children, adolescent, calcaneal apophysitis, sever’s disease, treatment, and management (full text publications, human studies). Systematic reviews, randomised control trials, case series, and case studies were included. The reference lists of the selected articles were also examined. The methodology, quality and risk of bias was examined and assessed using the PEDro scale. Results Nine articles were retrieved including three clinical trials involving randomisation, two case series, two retrospective case reviews, and two case reports. Effect size calculations and a meta analysis were unable to be completed due to the limited data reported within the literature. Numerous treatment options were reported throughout the literature, though few were examined against a control or alternate treatment option in well-designed trials. The limited evidence indicated that orthoses provided greater short-term pain relief than heel raises. Health practitioners should view these results with caution, as there were apparent methodological problems with the employed study design and limited follow-up of participants. Conclusion There is limited evidence to support the use

  16. Apophyseal Ossification of the Iliac Crest in Forensic Age Estimation: Computed Tomography Standards for Modern Australian Subadults.

    PubMed

    Lottering, Nicolene; Alston-Knox, Clair L; MacGregor, Donna M; Izatt, Maree T; Grant, Caroline A; Adam, Clayton J; Gregory, Laura S

    2017-03-01

    This study contrasts the ontogeny of the iliac crest apophysis using conventional radiography and multislice computed tomography (MSCT), providing probabilistic information for age estimation of modern Australian subadults. Retrospective abdominopelvic MSCT data acquired from 524 Australian individuals aged 7-25 and surveillance radiographs of adolescent idiopathic scoliosis patients included in the Paediatric Spine Research Group Progression Study (n = 531) were assessed. Ossification scoring of pseudo-radiographs and three-dimensional (3D) volume-rendered reconstructions using Risser (1958) quantitative descriptors indicate discrepancies in age estimates, stage allocation, and conflicting morphological progression. To mitigate visualization limitations associated with two-dimensional radiographs, we provide and validate a modified 3D-MSCT scoring tier of ossification, demonstrating complete fusion between 17.3-19.2 and 17.1-20.1 years in males and females. Legal demarcation for doli incapax presumption and age of majority (18 years) can be achieved using probability estimates from a fitted cumulative probit model for apophyseal fusion using the recalibrated standards.

  17. Failure of the human lumbar motion-segments resulting from anterior shear fatigue loading

    PubMed Central

    SKRZYPIEC, Daniel M.; NAGEL, Katrin; SELLENSCHLOH, Kay; KLEIN, Anke; PÜSCHEL, Klaus; MORLOCK, Michael M.; HUBER, Gerd

    2016-01-01

    An in-vitro experiment was designed to investigate the mode of failure following shear fatigue loading of lumbar motion-segments. Human male lumbar motion-segments (age 32–42 years, n=6) were immersed in Ringer solution at 37°C and repeatedly loaded, using a modified materials testing machine. Fatigue loading consisted of a sinusoidal shear load from 0 N to 1,500 N (750 N±750 N) applied to the upper vertebra of the motion-segment, at a frequency of 5 Hz. During fatigue experiments, several failure events were observed in the dynamic creep curves. Post-test x-ray, CT and dissection revealed that all specimens had delamination of the intervertebral disc. Anterior shear fatigue predominantly resulted in fracture of the apophyseal processes of the upper vertebrae (n=4). Exposure to the anterior shear fatigue loading caused motion-segment instability and resulted in vertebral slip corresponding to grade I and ‘mild’ grade II spondylolisthesis, as observed clinically. PMID:26829975

  18. Diagnostic Lumbar Puncture

    PubMed Central

    Doherty, Carolynne M; Forbes, Raeburn B

    2014-01-01

    Diagnostic Lumbar Puncture is one of the most commonly performed invasive tests in clinical medicine. Evaluation of an acute headache and investigation of inflammatory or infectious disease of the nervous system are the most common indications. Serious complications are rare, and correct technique will minimise diagnostic error and maximise patient comfort. We review the technique of diagnostic Lumbar Puncture including anatomy, needle selection, needle insertion, measurement of opening pressure, Cerebrospinal Fluid (CSF) specimen handling and after care. We also make some quality improvement suggestions for those designing services incorporating diagnostic Lumbar Puncture. PMID:25075138

  19. Quantification of lumbar endurance on a backup lumbar extension dynamometer.

    PubMed

    Hager, Staci M; Udermann, Brian E; Reineke, David M; Gibson, Mark H; Mayer, John M; Murray, Steven R

    2006-01-01

    We evaluated the reliability of static and dynamic lumbar muscle endurance measurements on a BackUP lumbar extension dynamometer. Sixteen healthy participants (8 male; 8 female) volunteered for this investigation. Fifty percent of each participant's body weight was calculated to determine the weight load utilized for the static (holding time) and dynamic (repetitions) lumbar extension endurance tests. Four separate tests (2 static, 2 dynamic) were conducted with at least a 24-hour rest period between tests. Test-retest intraclass correlations were shown to be high (static lumbar endurance, ICC = 0.92 (p < 0.0005); dynamic lumbar endurance, ICC = 0.93 (p < 0.0005) for both of the performed tests. Our results demonstrated that static and dynamic lumbar endurance can be assessed reliably on a BackUP lumbar extension dynamometer. Key PointsReliability studies that test lumbar endurance on machines that effectively stabilize the pelvis and isolate the lumbar extensors are limited.This is the first study to report reliability measures of static and dynamic lumbar endurance on a BackUP lumbar extension dynamometer.Static and dynamic lumbar endurance on a BackUP lumbar extension dynamometer, which uses a variety of pelvic stabilization mechanisms, can be reliably assessed in apparently healthy individuals.Future research is necessary to examine the reliability of lumbar extension endurance on the BackUP dynamometer in patient populations and validity in various settings.

  20. Lumbar MRI scan

    MedlinePlus

    ... may need a lumbar MRI if you have: Low back pain that does not get better after treatment Leg ... spine Injury or trauma to the lower spine Low back pain and a history or signs of cancer Multiple ...

  1. Minimally invasive lumbar foraminotomy.

    PubMed

    Deutsch, Harel

    2013-07-01

    Lumbar radiculopathy is a common problem. Nerve root compression can occur at different places along a nerve root's course including in the foramina. Minimal invasive approaches allow easier exposure of the lateral foramina and decompression of the nerve root in the foramina. This video demonstrates a minimally invasive approach to decompress the lumbar nerve root in the foramina with a lateral to medial decompression. The video can be found here: http://youtu.be/jqa61HSpzIA.

  2. The effect of sustained natural apophyseal glide (SNAG) combined with neurodynamics in the management of a patient with cervical radiculopathy: a case report.

    PubMed

    Anandkumar, Sudarshan

    2015-02-01

    This case report describes a 47-year-old female who presented with complaints of pain in the right elbow radiating down to the thumb. Physical examination revealed symptom reproduction with Spurling A test, upper limb neurodynamic testing-1 and right cervical rotation along with reduced symptoms with neck distraction. Clinical diagnosis of cervical radiculopathy (CR) was made based on a clinical prediction rule. This case report speculates a potentially first-time description of successful conservative management of CR in a patient utilizing simultaneous combination of sustained natural apophyseal glide and neurodynamic mobilization. Immediate improvements were seen in pain, cervical range of motion and functional abilities. The patient was discharged from physical therapy by the second week after four treatment sessions with complete pain resolution maintained at a four-month follow-up period.

  3. Limbus lumbar and sacral vertebral fractures.

    PubMed

    Mendez, Jorge S; Huete, Isidro L; Tagle, Patricio M

    2002-03-01

    We evaluated the fractures of the lumbar and sacral vertebral limbus by disc impingement at the peripheral ring apophysis in 23 adults associated with trauma in 16 of them. Lumbalgia, radicular pain and narrow canal symptoms are the presenting forms of this underdiagnosed pathology. CT is the best method of examination, while plain roentgenograms and MR are usually negative. Accurate diagnosis and surgical technique with larger exposure are needed to resect the fractured fragments and protruded disc material for decompressing the roots and the dural sac. Our results were very good on the majority of cases.

  4. LUMBAR DISC HERNIATION

    PubMed Central

    Vialle, Luis Roberto; Vialle, Emiliano Neves; Suárez Henao, Juan Esteban; Giraldo, Gustavo

    2015-01-01

    Lumbar disc herniation is the most common diagnosis among the degenerative abnormalities of the lumbar spine (affecting 2 to 3% of the population), and is the principal cause of spinal surgery among the adult population. The typical clinical picture includes initial lumbalgia, followed by progressive sciatica. The natural history of disc herniation is one of rapid resolution of the symptoms (four to six weeks). The initial treatment should be conservative, managed through medication and physiotherapy, sometimes associated with percutaneous nerve root block. Surgical treatment is indicated if pain control is unsuccessful, if there is a motor deficit greater than grade 3, if there is radicular pain associated with foraminal stenosis, or if cauda equina syndrome is present. The latter represents a medical emergency. A refined surgical technique, with removal of the extruded fragment and preservation of the ligamentum flavum, resolves the sciatic symptoms and reduces the risk of recurrence over the long term. PMID:27019834

  5. Lumbar spinal stenosis.

    PubMed Central

    Ciricillo, S F; Weinstein, P R

    1993-01-01

    Lumbar spinal stenosis, the results of congenital and degenerative constriction of the neural canal and foramina leading to lumbosacral nerve root or cauda equina compression, is a common cause of disability in middle-aged and elderly patients. Advanced neuroradiologic imaging techniques have improved our ability to localize the site of nerve root entrapment in patients presenting with neurogenic claudication or painful radiculopathy. Although conservative medical management may be successful initially, surgical decompression by wide laminectomy or an intralaminar approach should be done in patients with serious or progressive pain or neurologic dysfunction. Because the early diagnosis and treatment of lumbar spinal stenosis may prevent intractable pain and the permanent neurologic sequelae of chronic nerve root entrapment, all physicians should be aware of the different neurologic presentations and the treatment options for patients with spinal stenosis. Images PMID:8434469

  6. Saturn's Rings

    NASA Astrophysics Data System (ADS)

    Cuzzi, J. N.

    2014-12-01

    The rings are changing before our eyes; structure varies on all timescales and unexpected things have been discovered. Many questions have been answered, but some answers remain elusive (see Cuzzi et al 2010 for a review). Here we highlight the major ring science progress over the mission to date, and describe new observations planned for Cassini's final three years. Ring Composition and particle sizes: The rings are nearly all water ice with no other ices - so why are they reddish? The C Ring and Cassini Division are "dirtier" than the more massive B and A Rings, as shown by near-IR and, recently, microwave observations. Particle sizes, from stellar and radio occultations, vary from place to place. Ring structure, micro and macro: numerous spiral density waves and ubiquitous "self-gravity wakes" reveal processes which fostered planet formation in the solar system and elsewhere. However, big puzzles remain regarding the main ring divisions, the C Ring plateau structures, and the B Ring irregular structure. Moonlets, inside and out, seen and unseen: Two gaps contain sizeable moonlets, but more gaps seem to contain none; even smaller embedded "propeller" objects wander, systematically or randomly, through the A ring. Rubble pile ringmoons just outside the rings may escaped from the rings, and the recently discovered "Peggy" may be trying this as we watch. Impact bombardment of the rings: Comet fragments set the rings to rippling on century-timescales, and boulders crash through hourly; meanwhile, the constant hail of infalling Kuiper belt material has a lower mass flux than previously thought. Origin and Age of the Rings: The ring mass and bombardment play key roles. The ring mass is well known everywhere but in the B Ring (where most of it is). New models suggest how tidal breakup of evolving moons may have formed massive ancient rings, of which the current ring is just a shadow. During its last three years, the Cassini tour profile will allow entirely new

  7. Vascular ring

    MedlinePlus

    ... with aberrant subclavian and left ligamentum ateriosus; Congenital heart defect - vascular ring; Birth defect heart - vascular ring ... accounts for less than 1% of all congenital heart problems. The condition occurs as often in males ...

  8. Neptune's rings

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This 591-second exposure of the rings of Neptune were taken with the clear filter by the Voyager 2 wide-angle camera. The two main rings are clearly visible and appear complete over the region imaged. Also visible in this image is the inner faint ring and the faint band which extends smoothly from the ring roughly halfway between the two bright rings. Both of these newly discovered rings are broad and much fainter than the two narrow rings. The bright glare is due to over-exposure of the crescent on Neptune. Numerous bright stars are evident in the background. Both bright rings have material throughout their entire orbit, and are therefore continuous. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.

  9. Upper lumbar disk herniations.

    PubMed

    Cedoz, M E; Larbre, J P; Lequin, C; Fischer, G; Llorca, G

    1996-06-01

    Specific features of upper lumbar disk herniations are reviewed based on data from the literature and from a retrospective study of 24 cases treated surgically between 1982 and 1994 (seven at L1-L2 and 17 at L2-L3). Clinical manifestations are polymorphic, misleading (abdominogenital pain suggestive of a visceral or psychogenic condition, meralgia paresthetica, isolated sciatica; femoral neuralgia is uncommon) and sometimes severe (five cases of cauda equina syndrome in our study group). The diagnostic usefulness of imaging studies (radiography, myelography, computed tomography, magnetic resonance imaging) and results of surgery are discussed. The risk of misdiagnosis and the encouraging results of surgery are emphasized.

  10. Postlaminectomy Bilateral Lumbar Intraspinal Synovial Cysts

    PubMed Central

    Cho, Sung Ik; Lee, Jung Hwan

    2016-01-01

    Lumbar intraspinal synovial cysts are included in the difference diagnosis of lumbar radiculopathy. Developing imaging modalities has result in increased reporting about these lesions. However, the case of bilateral new lumbar intraspinal synovial cysts after laminectomy has been rarely reported. We report of a rare case with bilateral lumbar intraspinal synovial cysts after laminectomy, requiring surgical excision. PMID:27799997

  11. Vortex rings

    NASA Technical Reports Server (NTRS)

    Shariff, Karim; Leonard, Anthony

    1992-01-01

    The vortex-ring problem in fluid mechanics is examined generally in terms of formation, the steady state, the duration of the rings, and vortex interactions. The formation is studied by examining the generation of laminar and turbulent vortex rings and their resulting structures with attention given to the three stages of laminar ring development. Inviscid dynamics is addressed to show how core dynamics affects overall ring motion, and laminar vortex structures are described in two dimensions. Viscous and inviscid structures are related in terms of 'leapfrogging', head-on collisions, and collisions with a no-slip wall. Linear instability theory is shown to successfully describe observational data, although late stages in the breakdown are not completely understood. This study of vortex rings has important implications for key aerodynamic issues including sound generation, transport and mixing, and vortex interactions.

  12. Occult lumbar spinal stenosis.

    PubMed Central

    Choudhury, A R; Taylor, J C

    1977-01-01

    Twenty-eight patients presenting with low back pain, associated with sciatic or femoral neuropathy, were found to have lateral recess stenosis occurring as a result of hypertrophy of the facet joints, with preservation within normal limits of the sagittal AP diameter of the lumbar canal. Pathology was believed to be traumatic in origin, and the variable nature of the adhesions suggested recurrent inflammation; the hypertrophy of the facet joints may have been the result of traumatic inflammatory hyperaemia. Radiological investigations were unhelpful. The diagnosis of the condition was made at the time of surgical exploration by the findings of alteration of the facet joints, adhesions and fixity of the nerve roots, normal sagittal AP diameter of the canal, and absence of other significant lesions. Gratifying results were obtained with decompression by wide laminectomy with excision of overhanging facet joints and release of adhesions. PMID:894321

  13. [Intradural lumbar disk hernia].

    PubMed

    Alonso-Bartolomé, P; Canga, A; Vázquez-Barquero, A; García-Valtuille, R; Abascal, F; Cerezal, L

    2001-04-01

    Intradural disc herniation is a rare complication of degenerative disc disease. A correct diagnosis of this process is frequently difficult. If this entity is not preoperatively diagnosed and is omitted at surgery, severe neurologic sequels may be provoked. We report a case of a pathologically proven intradural disc herniation preoperatively diagnosed by MR imaging. Clinically, it was manifested by sudden onset of right leg ciatalgia and progressive right lower extremity weakness. The patient also referred a one-month history of sexual dysfunction. MR imaging revealed interruption of the low signal of the anulus fibrosus and of the posterior longitudinal ligament at L2-L3 level and a voluminous disc fragment migrated in the dural sac that showed rim enhancement with gadolinium.The clinical, neuroradiological, and surgical management of lumbar intradural disc herniation are reviewed.

  14. Planetary Rings

    NASA Technical Reports Server (NTRS)

    Cuzzi, Jeffrey N.

    1994-01-01

    Just over two decades ago, Jim Pollack made a critical contribution to our understanding of planetary ring particle properties, and resolved a major apparent paradox between radar reflection and radio emission observations. At the time, particle properties were about all there were to study about planetary rings, and the fundamental questions were, why is Saturn the only planet with rings, how big are the particles, and what are they made of? Since then, we have received an avalanche of observations of planetary ring systems, both from spacecraft and from Earth. Meanwhile, we have seen steady progress in our understanding of the myriad ways in which gravity, fluid and statistical mechanics, and electromagnetism can combine to shape the distribution of the submicron-to-several-meter size particles which comprise ring systems into the complex webs of structure that we now know them to display. Insights gained from studies of these giant dynamical analogs have carried over into improved understanding of the formation of the planets themselves from particle disks, a subject very close to Jim's heart. The now-complete reconnaissance of the gas giant planets by spacecraft has revealed that ring systems are invariably found in association with families of regular satellites, and there is ark emerging perspective that they are not only physically but causally linked. There is also mounting evidence that many features or aspects of all planetary ring systems, if not the ring systems themselves, are considerably younger than the solar system

  15. [Lumbar stabilization exercises].

    PubMed

    Vásquez-Ríos, Jorge Rodrigo; Nava-Bringas, Tania Inés

    2014-01-01

    Antecedentes: el ejercicio es la intervención con mayor grado de evidencia de eficacia para el tratamiento del dolor crónico de la espalda baja, con beneficio superior en términos de dolor y funcionalidad, en comparación con cualquiera otra intervención. Existe una amplia variedad de ejercicios diseñados; sin embargo, actualmente los llamados ejercicios de estabilización lumbar adquiririeron una popularidad creciente entre los clínicos que están en contacto con enfermedades de la columna. Sin embargo, existe controversia en cuanto a la prescripción adecuada de los mismos y los múltiples protocolos publicados. Objetivo: analizar la bibliografía científica acerca del uso y prescripción de estos ejercicios para favorecer la mejor toma de decisiones enlos clínicos y diseñar, con base a la evidencia, el programa más adecuado para cada paciente. Conclusión: se encontró que este programa es una herramienta esencial en el tratamiento del dolor de espalda baja, en la etapa terapéutica y en la preventiva.

  16. Lumbar intrathecal ligaments.

    PubMed

    Kershner, David E; Binhammer, Robert T

    2002-03-01

    A meticulous examination was performed on 56 vertebral columns from cadavers between 64 and 89 years of age. Identification of all contents within the dural sac was completed; however, the main focus was the cauda equina and lumbar region. In addition to scope dissection, radiographs and histological preparations were used to identify structures, tissue types, and any possible pathology. Discrete intrathecal ligamentous bands were observed in all cadavers examined. They were found randomly binding the dorsal nerve roots of the cauda equina to the dura. Occasional binding of the ventral nerve roots to the dorsal roots was observed. Histological examination demonstrated a dense collagen ligament varying between 0.13 and 0.35 microm in thickness and from 3 mm to 3.5 cm in length. The average number of ligaments found per cadaver was 18. These ligaments displayed a broad base attachment to the nerve root or dura of approximately 3 mm. Looping of the nerve roots associated with these ligaments was seen in one cadaver with a burst fracture. Electron microscopic studies of these ligaments demonstrated similarities to denticulate ligaments. It is suggested that the intrathecal ligaments represent remnants from fetal development of the denticulate ligaments.

  17. Nerve Wrapping of the Sciatic Nerve With Acellular Dermal Matrix in Chronic Complete Proximal Hamstring Ruptures and Ischial Apophyseal Avulsion Fractures

    PubMed Central

    Haus, Brian M.; Arora, Danny; Upton, Joseph; Micheli, Lyle J.

    2016-01-01

    Background: Patients with chronic injuries of the proximal hamstring can develop significant impairment because of weakness of the hamstring muscles, sciatic nerve compression from scar formation, or myositis ossificans. Purpose: To describe the surgical outcomes of patients with chronic injury of the proximal hamstrings who were treated with hamstring repair and sciatic neurolysis supplemented with nerve wrapping with acellular dermal matrix. Study Design: Retrospective case series; Level of evidence, 4. Methods: Fifteen consecutive patients with a diagnosis of chronic complete proximal hamstring rupture or chronic ischial tuberosity apophyseal avulsion fracture (mean age, 39.67 years; range, 14-69 years) were treated with proximal hamstring repair and sciatic neurolysis supplemented with nerve wrapping with acellular dermal matrix. Nine patients had preoperative sciatica, and 6 did not. Retrospective chart review recorded clinical outcomes measured by the degree of pain relief, the rate of return to activities, and associated postoperative complications. Results: All 15 patients were followed in the postoperative period for an average of 16.6 months. Postoperatively, there were 4 cases of transient sciatic nerve neurapraxia. Four patients (26%) required postoperative betamethasone sodium phosphate (Celestone Soluspan) injectable suspension USP 6 mg/mL. Among the 9 patients with preoperative sciatica, 6 (66%) had a good or excellent outcome and were able to return to their respective activities/sports; 3 (33%) had persistent chronic pain. One of these had persistent sciatic neuropathy that required 2 surgical reexplorations and scar excision after development of recurrent extraneural scar formation. Among the 6 without preoperative sciatica, 100% had a good or excellent outcomes and 83% returned to their respective activities/sports. Better outcomes were observed in younger patients, as the 3 cases of persistent chronic sciatic pain were in patients older than 45

  18. Ghostly Ring

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Click on image for poster version

    This image shows a ghostly ring extending seven light-years across around the corpse of a massive star. The collapsed star, called a magnetar, is located at the exact center of this image. NASA's Spitzer Space Telescope imaged the mysterious ring around magnetar SGR 1900+14 in infrared light. The magnetar itself is not visible in this image, as it has not been detected at infrared wavelengths (it has been seen in X-ray light).

    Magnetars are formed when a massive giant star ends its life in a supernova explosion, leaving behind a super dense neutron star with an incredibly strong magnetic field. The ring seen by Spitzer could not have formed during the original explosion, as any material as close to the star as the ring would have been disrupted by the supernova shock wave. Scientists suspect that the ring my actually be the edges of a bubble that was hollowed out by an explosive burst from the magnetar in 1998. The very bright region near the center of the image is a cluster of young stars, which may be illuminating the inner edge of the bubble, making it look like a ring in projection.

    This composite image was taken using all three of Spitzer's science instruments. The blue color represents 8-micron infrared light taken by the infrared array camera, green is 16-micron light from the infrared spectograph, and red is 24-micron radiation from the multiband imaging photometer.

  19. Luminescent Rings

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This view shows the unlit face of Saturn's rings, visible via scattered and transmitted light. In these views, dark regions represent gaps and areas of higher particle densities, while brighter regions are filled with less dense concentrations of ring particles.

    The dim right side of the image contains nearly the entire C ring. The brighter region in the middle is the inner B ring, while the darkest part represents the dense outer B Ring. The Cassini Division and the innermost part of the A ring are at the upper-left.

    Saturn's shadow carves a dark triangle out of the lower right corner of this image.

    The image was taken in visible light with the Cassini spacecraft wide-angle camera on June 8, 2005, at a distance of approximately 433,000 kilometers (269,000 miles) from Saturn. The image scale is 22 kilometers (14 miles) per pixel.

    The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

    For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org .

  20. Cave Rings

    DTIC Science & Technology

    2010-10-13

    hypothesis, that cave rings are formed in the same manner as coffee rings[3], that is, due to the enhanced deposition at the edges of sessile drops ...Literature The ‘splash ring’ conjecture is described in [5]. It is claimed that 45◦ is the most probable angle for secondary drops to be ejected at, and that...ring’ is the deposit formed when a sessile drop of a solution containing dissolved particles, such as coffee or salt, dries. This was investigated by

  1. Degenerative lumbar spinal stenosis and lumbar spine configuration

    PubMed Central

    Hamoud, K.; May, H.; Hay, O.; Medlej, B.; Masharawi, Y.; Peled, N.; Hershkovitz, I.

    2010-01-01

    As life expectancy increases, degenerative lumbar spinal stenosis (DLSS) becomes a common health problem among the elderly. DLSS is usually caused by degenerative changes in bony and/or soft tissue elements. The poor correlation between radiological manifestations and the clinical picture emphasizes the fact that more studies are required to determine the natural course of this syndrome. Our aim was to reveal the association between lower lumbar spine configuration and DLSS. Two groups were studied: the first included 67 individuals with DLSS (mean age 66 ± 10) and the second 100 individuals (mean age 63.4 ± 13) without DLSS-related symptoms. Both groups underwent CT images (Philips Brilliance 64) and the following measurements were performed: a cross-section area of the dural sac, vertebral body dimensions (height, length and width), AP diameter of the bony spinal canal, lumbar lordosis and sacral slope angles. All measurements were taken at L3 to S1. Vertebral body lengths were significantly greater in the DLSS group at all levels compared to the control, whereas anterior vertebral body heights (L3, L4, L5) and middle vertebral heights (L3, L5) were significantly smaller in the LSS group. Lumbar lordosis, sacral slope and bony spinal canal were significantly smaller in the DLSS compared to the control. We conclude that the size and shape of vertebral bodies and canals significantly differed between the study groups. A tentative model is suggested to explain the association between these characteristics and the development of degenerative spinal stenosis. PMID:20652366

  2. The human lumbar dorsal rami.

    PubMed Central

    Bogduk, N; Wilson, A S; Tynan, W

    1982-01-01

    The L 1-4 dorsal rami tend to form three branches, medial, lateral, and intermediate, which are distributed, respectively, to multifidus, iliocostalis, and longissimus. The intertransversarii mediales are innervated by a branch of the dorsal ramus near the origin of the medial branch. The L 4 dorsal ramus regularly forms three branches while the L 1-3 levels the lateral and intermediate branches may, alternatively, arise from a short common stem. The L 5 dorsal ramus is much longer than the others and forms only a medial and an intermediate branch. Each lumbar medial branch innervates two adjacent zygapophysial joints and ramifies in multifidus, supplying only those fascicles which arise from the spinous process with the same segmental number as the nerve. The comparative anatomy of the lumbar dorsal rami is discussed and the applied anatomy with respect to 'rhizolysis', 'facet denervation' and diagnostic paraspinal electromyography is described. PMID:7076562

  3. Assessment of Lumbar Lordosis and Lumbar Core Strength in Information Technology Professionals

    PubMed Central

    Mehta, Roma Satish; Dabadghav, Rachana; Rairikar, Savita; Shayam, Ashok; Sancheti, Parag

    2016-01-01

    Study Design Observational study. Purpose To correlate lumbar lordosis and lumbar core strength in information technology (IT) professionals. Overview of Literature IT professionals have to work for long hours in a sitting position, which can affect lumbar lordosis and lumbar core strength. Methods Flexicurve was used to assess the lumbar lordosis, and pressure biofeedback was used to assess the lumbar core strength in the IT professionals. All subjects, both male and female, with and without complaint of low back pain and working for two or more years were included, and subjects with a history of spinal surgery or spinal deformity were excluded from the study. Analysis was done using Pearson's correlation. Results For the IT workers, no correlation was seen between lumbar lordosis and lumbar core strength (r=–0.04); however, a weak negative correlation was seen in IT people who complained of pain (r=–0.12), while there was no correlation of lumbar lordosis and lumbar core in IT people who had no complains of pain (r=0.007). Conclusions The study shows that there is no correlation of lumbar lordosis and lumbar core strength in IT professionals, but a weak negative correlation was seen in IT people who complained of pain. PMID:27340529

  4. Lumbar lordosis of extinct hominins.

    PubMed

    Been, Ella; Gómez-Olivencia, Asier; Kramer, Patricia A

    2012-01-01

    The lordotic curvature of the lumbar spine (lumbar lordosis) in humans is a critical component in the ability to achieve upright posture and bipedal gait. Only general estimates of the lordotic angle (LA) of extinct hominins are currently available, most of which are based on the wedging of the vertebral bodies. Recently, a new method for calculating the LA in skeletal material has become available. This method is based on the relationship between the lordotic curvature and the orientation of the inferior articular processes relative to vertebral bodies in the lumbar spines of living primates. Using this relationship, we developed new regression models in order to calculate the LAs in hominins. The new models are based on primate group-means and were used to calculate the LAs in the spines of eight extinct hominins. The results were also compared with the LAs of modern humans and modern nonhuman apes. The lordotic angles of australopithecines (41° ± 4), H. erectus (45°) and fossil H. sapiens (54° ± 14) are similar to those of modern humans (51° ± 11). This analysis confirms the assumption that human-like lordotic curvature was a morphological change that took place during the acquisition of erect posture and bipedalism as the habitual form of locomotion. Neandertals have smaller lordotic angles (LA = 29° ± 4) than modern humans, but higher angles than nonhuman apes (22° ± 3). This suggests possible subtle differences in Neandertal posture and locomotion from that of modern humans.

  5. Kayser-Fleischer Rings

    MedlinePlus

    ... to know about Wilson Disease Kayser-Fleischer Rings Definition Kayser-Fleischer Ring: Clinical sign. Brownish-yellow ring ... Diet & Nutrition Kayser-Fleischer Rings Wilson Disease FAQs Definitions Transplantation For Patients & Families Resources Membership Events Centers ...

  6. Ringing wormholes

    SciTech Connect

    Konoplya, R.A.; Molina, C.

    2005-06-15

    We investigate the response of traversable wormholes to external perturbations through finding their characteristic frequencies and time-domain profiles. The considered solution describes traversable wormholes between the branes in the two brane Randall-Sundrum model and was previously found within Einstein gravity with a conformally coupled scalar field. The evolution of perturbations of a wormhole is similar to that of a black hole and represents damped oscillations (ringing) at intermediately late times, which are suppressed by power-law tails (proportional to t{sup -2} for monopole perturbations) at asymptotically late times.

  7. Primary lumbar hernia: A rarely encountered hernia

    PubMed Central

    Sundaramurthy, Sharada; Suresh, H.B.; Anirudh, A.V.; Prakash Rozario, Anthony

    2015-01-01

    Introduction Lumbar hernia is an uncommon abdominal wall hernia, making its diagnosis and management a challenge to the treating surgeon. Presentation may be misleading and diagnosis often missed. An imaging study forms an indispensable aid in the diagnosis and surgery is the only treatment option. Presentation of case A 42 year old male presented with history of pain in lower back of 4 years duration and was being treated symptomatically over 4 years with analgesics and physiotherapy. He had noticed a swelling over the left side of his mid-back and consequently on examination was found to have a primary acquired lumbar hernia arising from the deep superior lumbar triangle of Grynfelt. Diagnosis was confirmed by Computed Tomographic imaging. Discussion A lumbar hernia may be primary or secondary with only about 300 cases of primary lumbar hernia reported in literature. Lumbar hernias manifest through two possible defects in the posterior abdominal wall, the superior being more common. Management remains surgical with various techniques emerging over the years. The patient at our center underwent an open sublay mesh repair with excellent outcome. Conclusion A surgeon may encounter a primary lumbar hernia perhaps once in his lifetime making it an interesting surgical challenge. Sound anatomical knowledge and adequate imaging are indispensable. Inspite of advances in minimally invasive surgery, it cannot be universally applied to patients with lumbar hernia and management requires a more tailored approach. PMID:26812667

  8. Lumbar adhesive arachnoiditis. Etiologic and pathologic aspects.

    PubMed

    Quiles, M; Marchisello, P J; Tsairis, P

    1978-03-01

    The etiologic factors and pathologic findings in 38 patients with lumbar arachnoiditis are presented. Lumbar spine surgery and the injection of contrast materials prior to the diagnosis of this condition are considered the most important factors in its genesis. In this series, there was microscopic evidence of arachnoiditis ossificans in 3 patients and arachnoiditis calcificans in 1 patient.

  9. Spontaneous hemorrhage into a lumbar synovial cyst

    PubMed Central

    Alen, Jose F.; Ramos, Ana; Lobato, Ramiro D.; Lagares, Alfonso

    2010-01-01

    Lumbar synovial cysts frequently present with back pain, chronic radiculopathy and/or progressive symptoms of spinal canal compromise. These cysts generally appear in the context of degenerative lumbar spinal disease. Few cases of spontaneous hemorrhage into synovial cysts have been reported in the literature. PMID:20174835

  10. [Lumbar pain in old age].

    PubMed

    Baumgartner, H

    1996-10-22

    In advanced age, lumbar pain is less frequently caused by occupational stress and psychosomatic factors. Unstable segments and spondylo-arthrotic degeneration can lead to muscular strain whenever insufficient secondary stability and missing muscular equilibrium are involved. In the differential diagnosis one must distinguish between osteoporosis and spinal stenosis, which increases in frequency with age. Pain due to internal or gynecological problems must be excluded. From the therapeutic point of view, patients should be instructed in ergonomics and the simple application of physiotherapeutic procedures, e.g. heat and cold. Analgetics become increasingly important with age, consequently resulting in reduced use of antirheumatics. There exists enough evidence to show that muscular training of the lumbar muscles play an important role in the secondary prevention of lumbar pain in elderly people as well. Essentially, it can be stated that physical age is not directly related to possible ailment. The change of occupational obligations, with possibilities to adapt to personal stress levels, as well as the positive attitude towards everyday life in retirement have a major influence in accepting and handling ability of problems, concerning pain. In the department of Physical Medicine, Rehabilitation and Rheumatology of the Clinic Wilhelm Schulthess it was found that among 7806 patients with lower back pain (1990-1995) 43.3% involved the ages of 40 to 60 and 31.3% the ages of 60 to 80. More distinctly than in younger patients, older aged patients tend to show a marked discrepancy between radiological findings and effective pain. Lower back pains of elderly patients are of a different nature from those found in younger or middle-aged people. Ischialgia due to the protrusion of an intervertebral disk or an acute lumbovertebral syndrome caused by muscular instability are found much less frequently.

  11. Lumbar Epidural Varix Mimicking Disc Herniation

    PubMed Central

    Bursalı, Adem; Guvenal, Ahmet Burak; Yaman, Onur

    2016-01-01

    Lumbar radiculopathy is generally caused by such well-recognized entity as lumbar disc herniation in neurosurgical practice; however rare pathologies such as thrombosed epidural varix may mimic them by causing radicular symptoms. In this case report, we present a 26-year-old man with the complaint of back and right leg pain who was operated for right L4–5 disc herniation. The lesion interpreted as an extruded disc herniation preoperatively was found to be a thrombosed epidural varix compressing the nerve root preoperatively. The nerve root was decompressed by shrinking the lesion with bipolar thermocoagulation and excision. The patient's complaints disappeared in the postoperative period. Thrombosed lumbar epidural varices may mimic lumbar disc herniations both radiologically and clinically. Therefore, must be kept in mind in the differential diagnosis of lumbar disc herniations. Microsurgical techniques are mandatory for the treatment of these pathologies and decompression with thermocoagulation and excision is an efficient method. PMID:27446525

  12. Lumbar intraspinal extradural ganglion cysts.

    PubMed

    Cho, Sung Min; Rhee, Woo Tack; Choi, Soo Jung; Eom, Dae Woon

    2009-07-01

    The lumbar intraspinal epidural ganglion cyst has been a rare cause of the low back pain or leg pain. Ganglion cysts and synovial cysts compose the juxtafacet cysts. Extensive studies have been performed about the synovial cysts, however, very little has been known about the ganglion cyst. Current report is about two ganglion cysts associated with implicative findings in young male patients. We discuss about the underlying pathology of the ganglion cyst based on intraoperative evidences, associated disc herniation at the same location or severe degeneration of the ligament flavum that the cyst originated from in young patients.

  13. Kinetics of ring formation

    NASA Astrophysics Data System (ADS)

    Ben-Naim, E.; Krapivsky, P. L.

    2011-06-01

    We study reversible polymerization of rings. In this stochastic process, two monomers bond and, as a consequence, two disjoint rings may merge into a compound ring or a single ring may split into two fragment rings. This aggregation-fragmentation process exhibits a percolation transition with a finite-ring phase in which all rings have microscopic length and a giant-ring phase where macroscopic rings account for a finite fraction of the entire mass. Interestingly, while the total mass of the giant rings is a deterministic quantity, their total number and their sizes are stochastic quantities. The size distribution of the macroscopic rings is universal, although the span of this distribution increases with time. Moreover, the average number of giant rings scales logarithmically with system size. We introduce a card-shuffling algorithm for efficient simulation of the ring formation process and we present numerical verification of the theoretical predictions.

  14. Ringing phenomenon of the fiber ring resonator.

    PubMed

    Ying, Diqing; Ma, Huilian; Jin, Zhonghe

    2007-08-01

    A resonator fiber-optic gyro (R-FOG) is a high-accuracy inertial rotation sensor based on the Sagnac effect. A fiber ring resonator is the core sensing element in the R-FOG. When the frequency of the fiber ring resonator input laser is swept linearly with time, ringing of the output resonance curve is observed. The output field of the fiber ring resonator is derived from the superposition of the light transmitted through the directional coupler directly and the multiple light components circulated in the fiber ring resonator when the frequency of the laser is swept. The amplitude and phase of the output field are analyzed, and it is found that the difference in time for different light components in the fiber ring resonator to reach a point of destructive interference causes the ringing phenomenon. Finally the ringing phenomenon is observed in experiments, and the experimental results agree with the theoretical analysis well.

  15. Lumbar stenosis: clinical case☆☆☆

    PubMed Central

    Sá, Pedro; Marques, Pedro; Alpoim, Bruno; Rodrigues, Elisa; Félix, António; Silva, Luís; Leal, Miguel

    2014-01-01

    Lumbar stenosis is an increasingly common pathological condition that is becoming more frequent with increasing mean life expectancy, with high costs for society. It has many causes, among which degenerative, neoplastic and traumatic causes stand out. Most of the patients respond well to conservative therapy. Surgical treatment is reserved for patients who present symptoms after implementation of conservative measures. Here, a case of severe stenosis of the lumbar spine at several levels, in a female patient with pathological and surgical antecedents in the lumbar spine, is presented. The patient underwent two different decompression techniques within the same operation. PMID:26229836

  16. ISASS Policy Statement – Lumbar Artificial Disc

    PubMed Central

    Garcia, Rolando

    2015-01-01

    Purpose The primary goal of this Policy Statement is to educate patients, physicians, medical providers, reviewers, adjustors, case managers, insurers, and all others involved or affected by insurance coverage decisions regarding lumbar disc replacement surgery. Procedures This Policy Statement was developed by a panel of physicians selected by the Board of Directors of ISASS for their expertise and experience with lumbar TDR. The panel's recommendation was entirely based on the best evidence-based scientific research available regarding the safety and effectiveness of lumbar TDR. PMID:25785243

  17. Asymmetric dipolar ring

    DOEpatents

    Prosandeev, Sergey A.; Ponomareva, Inna V.; Kornev, Igor A.; Bellaiche, Laurent M.

    2010-11-16

    A device having a dipolar ring surrounding an interior region that is disposed asymmetrically on the ring. The dipolar ring generates a toroidal moment switchable between at least two stable states by a homogeneous field applied to the dipolar ring in the plane of the ring. The ring may be made of ferroelectric or magnetic material. In the former case, the homogeneous field is an electric field and in the latter case, the homogeneous field is a magnetic field.

  18. Adhesive arachnoiditis following lumbar myelography.

    PubMed

    Skalpe, I O

    1978-03-01

    Late sequelae (adhesive arachnoiditis) have been reported following myelography with the oily contrast medium (Pantopaque) and with the ionic water-soluble contrast media methiodal sodium (Abrodil, Conturex, Kontrast U) meglumine iothalamate (Conray Meglumine) and meglumine iocarmate (Bis-Conray, Dimer-X). Adhesive arachnoiditis has not yet been reported after the use of the nonionic water-soluble contrast medium metrizamide (Amipaque). Thus, this is considered the contrast medium of choice for lumbar myelography. Using the recommended dose of 10 ml with an iodine concentration of 170 mg/ml for this examination, adhesive arachnoiditis is unlikely to occur. Increased osmolality of spinal fluid after injection of contrast medium is related to increased frequency of arachnoiditis.

  19. Lumbar herniated disc: spontaneous regression

    PubMed Central

    Yüksel, Kasım Zafer

    2017-01-01

    Background Low back pain is a frequent condition that results in substantial disability and causes admission of patients to neurosurgery clinics. To evaluate and present the therapeutic outcomes in lumbar disc hernia (LDH) patients treated by means of a conservative approach, consisting of bed rest and medical therapy. Methods This retrospective cohort was carried out in the neurosurgery departments of hospitals in Kahramanmaraş city and 23 patients diagnosed with LDH at the levels of L3−L4, L4−L5 or L5−S1 were enrolled. Results The average age was 38.4 ± 8.0 and the chief complaint was low back pain and sciatica radiating to one or both lower extremities. Conservative treatment was administered. Neurological examination findings, durations of treatment and intervals until symptomatic recovery were recorded. Laségue tests and neurosensory examination revealed that mild neurological deficits existed in 16 of our patients. Previously, 5 patients had received physiotherapy and 7 patients had been on medical treatment. The number of patients with LDH at the level of L3−L4, L4−L5, and L5−S1 were 1, 13, and 9, respectively. All patients reported that they had benefit from medical treatment and bed rest, and radiologic improvement was observed simultaneously on MRI scans. The average duration until symptomatic recovery and/or regression of LDH symptoms was 13.6 ± 5.4 months (range: 5−22). Conclusions It should be kept in mind that lumbar disc hernias could regress with medical treatment and rest without surgery, and there should be an awareness that these patients could recover radiologically. This condition must be taken into account during decision making for surgical intervention in LDH patients devoid of indications for emergent surgery. PMID:28119770

  20. Saturn's Spectacular Ring System

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.; DeVincenzi, Donald (Technical Monitor)

    2001-01-01

    Saturn's beautiful rings have fascinated astronomers since they were first observed by Galileo in 1610. The main rings consist of solid particles mostly in the 1 cm - 10 m range, composed primarily of water ice. The ring disk is exceptionally thin - the typical local thickness of the bright rings is tens of meters, whereas the diameter of the main rings is 250,000 km! The main rings exhibit substantial radial variations "ringlets", many of which are actively maintained via gravitational perturbations from Saturn's moons. Exterior to the main rings lie tenuous dust rings, which have little mass but occupy a very large volume of space. This seminar will emphasize the physics of ring-moon interactions, recent advances in our understanding of various aspects of the rings obtained from observations taken during 1995 when the rings appeared edge-on to the Earth and then to the Sun, and observations in subsequent years from HST.

  1. Lumbar Puncture (Spinal Tap) (For Parents)

    MedlinePlus

    ... treatment while waiting for the results of the culture. Risks A lumbar puncture is considered a safe procedure with minimal risks. Most of the time, there are no complications. In some instances, a ...

  2. Fractures of the Thoracic and Lumbar Spine

    MedlinePlus

    .org Fractures of the Thoracic and Lumbar Spine Page ( 1 ) Spinal fractures can vary widely in severity. While some fractures are very serious injuries that require emergency treatment, other fractures can ...

  3. Scoliosis secondary to lumbar osteoid osteoma

    PubMed Central

    Zhang, Haiping; Niu, Xingbang; Wang, Biao; He, Simin; Hao, Dingjun

    2016-01-01

    Abstract Rationale: Lumbar osteoid osteoma has a low incidence, which could easily lead to scoliosis. Patient concerns: Scoliosis secondary to lumbar osteoid osteoma could be easily misdiagnosed when patients do not complain of obvious symptoms. Diagnoses: We reported a case of a 9-year-old boy with back deformity that was firstly diagnosed with scoliosis at the local hospital. After prescribed with orthosis, the patient experienced aggravating pain that could not be relieved with painkillers. After he admitted to our hospital for further medical advice, he was prescribed to complete radiological examinations. Considering his radiological examination results and his medical history, correct diagnosis of lumbar osteoid osteoma was made. Interventions: Surgical intervention of posterior lesion resection was conducted after diagnosis. Intra-operative frozen pathology indicated features of osteoid osteoma. As the lesion involved inferior articular process of L5, which could cause lumbar instability after lesion resection, internal fixation was conducted at L4-S1 segment, and posterolateral bone fusion was also conducted at L5-S1 segment. Outcomes: Three months after operation, the patient showed marked improvement of scoliosis deformity and great relief of lumbar pain. Lessons subsections: Although spine osteoid osteoma is clinically rare, it shall not be overlooked when young patients present with scoliosis first. Radiological results including computed tomography and magnetic resonance imaging shall be taken carefully as reference when making diagnosis. Surgical intervention of lesion resection could well improve scoliosis and relieve lumbar pain. PMID:27893671

  4. Automatic Lumbar Spondylolisthesis Measurement in CT Images.

    PubMed

    Liao, Shu; Zhan, Yiqiang; Dong, Zhongxing; Yan, Ruyi; Gong, Liyan; Zhou, Xiang Sean; Salganicoff, Marcos; Fei, Jun

    2016-07-01

    Lumbar spondylolisthesis is one of the most common spinal diseases. It is caused by the anterior shift of a lumbar vertebrae relative to subjacent vertebrae. In current clinical practices, staging of spondylolisthesis is often conducted in a qualitative way. Although meyerding grading opens the door to stage spondylolisthesis in a more quantitative way, it relies on the manual measurement, which is time consuming and irreproducible. Thus, an automatic measurement algorithm becomes desirable for spondylolisthesis diagnosis and staging. However, there are two challenges. 1) Accurate detection of the most anterior and posterior points on the superior and inferior surfaces of each lumbar vertebrae. Due to the small size of the vertebrae, slight errors of detection may lead to significant measurement errors, hence, wrong disease stages. 2) Automatic localize and label each lumbar vertebrae is required to provide the semantic meaning of the measurement. It is difficult since different lumbar vertebraes have high similarity of both shape and image appearance. To resolve these challenges, a new auto measurement framework is proposed with two major contributions: First, a learning based spine labeling method that integrates both the image appearance and spine geometry information is designed to detect lumbar vertebrae. Second, a hierarchical method using both the population information from atlases and domain-specific information in the target image is proposed for most anterior and posterior points positioning. Validated on 258 CT spondylolisthesis patients, our method shows very similar results to manual measurements by radiologists and significantly increases the measurement efficiency.

  5. Stirling engine piston ring

    DOEpatents

    Howarth, Roy B.

    1983-01-01

    A piston ring design for a Stirling engine wherein the contact pressure between the piston and the cylinder is maintained at a uniform level, independent of engine conditions through a balancing of the pressure exerted upon the ring's surface and thereby allowing the contact pressure on the ring to be predetermined through the use of a preloaded expander ring.

  6. Birth Control Ring

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Birth Control Ring KidsHealth > For Teens > Birth Control Ring Print A A A What's in this ... español Anillo vaginal anticonceptivo What Is It? The birth control ring is a soft, flexible, doughnut-shaped ring ...

  7. New Dust Belts of Uranus: One Ring, Two Ring, Red Ring, Blue Ring

    SciTech Connect

    de Pater, I; Hammel, H B; Gibbard, S G; Showalter, M R

    2006-02-02

    We compare near-infrared observations of the recently discovered outer rings of Uranus with HST results. We find that the inner ring, R/2003 U 2, is red, whereas the outer ring, R/2003 U 1, is very blue. Blue is an unusual color for rings; Saturn's enigmatic E ring is the only other known example. By analogy to the E ring, R/2003 U 1 is probably produced via impacts into the embedded moon Mab, which apparently orbits at a location where non-gravitational perturbations favor the survival and spreading of sub-micron sized dust. R/2003 U 2 more closely resembles Saturn's G ring.

  8. Magnetic Resonance Imaging (MRI): Lumbar Spine (For Parents)

    MedlinePlus

    ... If You Have Questions en español Resonancia magnética: columna lumbar What It Is Magnetic resonance imaging (MRI) ... MORE ON THIS TOPIC Magnetic Resonance Imaging (MRI): Cervical Spine Lumbar Puncture (Spinal Tap) Magnetic Resonance Imaging ( ...

  9. Strength gains through lumbar lordosis restoration

    PubMed Central

    Morningstar, Mark W

    2003-01-01

    Abstract Objective To test the hypothesis that restoring the lumbar lordosis will increase a patient's voluntary muscular strength and decrease back pain symptoms. Clinical Features A patient was diagnosed with mechanical low back pain. The initial radiographic study revealed a loss of the lumbar lordosis. The patient determined his maximum bench press prior to the treatment program. The treatment outcome was based upon post-intervention radiographs, a Borg pain scale, and the patient's post-intervention maximum bench press. Intervention and Outcome The treatment program consisted of warm-up exercises, spinal manipulation, rehabilitative exercises, neuromuscular re-education, and prescribed home care. The treatment period consisted of 12 visits in the first 4 weeks, followed by once weekly for another 12 weeks, for a total of 24 visits in 4 months. In the first month, the Borg scale decreased from 5/10 to 0/10, and after 4 months the lumbar lordosis was increased from 2° to 31°. The sacral base angle (Ferguson's angle) increased from 18° to 31°. The patient's maximum bench press also increased from 245 pounds to 305 pounds. Conclusion Restoration of the lumbar lordosis appears to have a positive effect on muscular strength. This study supports the previous premise that a lumbar lordosis provides an inherent mechanical advantage for strength and stability. PMID:19674610

  10. Economic impact of minimally invasive lumbar surgery

    PubMed Central

    Hofstetter, Christoph P; Hofer, Anna S; Wang, Michael Y

    2015-01-01

    Cost effectiveness has been demonstrated for traditional lumbar discectomy, lumbar laminectomy as well as for instrumented and noninstrumented arthrodesis. While emerging evidence suggests that minimally invasive spine surgery reduces morbidity, duration of hospitalization, and accelerates return to activites of daily living, data regarding cost effectiveness of these novel techniques is limited. The current study analyzes all available data on minimally invasive techniques for lumbar discectomy, decompression, short-segment fusion and deformity surgery. In general, minimally invasive spine procedures appear to hold promise in quicker patient recovery times and earlier return to work. Thus, minimally invasive lumbar spine surgery appears to have the potential to be a cost-effective intervention. Moreover, novel less invasive procedures are less destabilizing and may therefore be utilized in certain indications that traditionally required arthrodesis procedures. However, there is a lack of studies analyzing the economic impact of minimally invasive spine surgery. Future studies are necessary to confirm the durability and further define indications for minimally invasive lumbar spine procedures. PMID:25793159

  11. Jupiter's Main Ring/Ring Halo

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A mosaic of four images taken through the clear filter (610 nanometers) of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft on November 8, 1996, at a resolution of approximately 46 kilometers (28.5 miles) per picture element (pixel) along Jupiter's rings. Because the spacecraft was only about 0.5 degrees above the ring plane, the image is highly foreshortened in the vertical direction. The images were obtained when Galileo was in Jupiter's shadow, peering back toward the Sun; the ring was approximately 2.3 million kilometers (1.4 million miles) away. The arc on the far right of the image is produced when sunlight is scattered by small particles comprising Jupiter's upper atmospheric haze. The ring also efficiently scatters light, indicating that much of its brightness is due to particles that are microns or less in diameter. Such small particles are believed to have human-scale lifetimes, i.e., very brief compared to the solar system's age.

    Jupiter's ring system is composed of three parts - - a flat main ring, a lenticular halo interior to the main ring, and the gossamer ring, outside the main ring. The near and far arms of Jupiter's main ring extend horizontally across the mosaic, joining together at the ring's ansa, on the figure's far left side. The near arm of the ring appears to be abruptly truncated close to the planet, at the point where it passes into Jupiter's shadow. Some radial structure is barely visible across the ring's ansa (top image). A faint mist of particles can be seen above and below the main rings. This vertically extended 'halo' is unusual in planetary rings, and is probably caused by electromagnetic forces pushing the smallest grains out of the ring plane. Because of shadowing, the halo is not visible close to Jupiter in the lower right part of the mosaic. To accentuate faint features in the bottom image of the ring halo, different brightnesses are shown through color. Brightest features are white or yellow and the

  12. Use of autologous growth factors in lumbar spinal fusion.

    PubMed

    Lowery, G L; Kulkarni, S; Pennisi, A E

    1999-08-01

    The results of spinal fusion, especially posteriorly above the lumbosacral junction, have been mixed. Autologous growth factor concentrate (AGF) prepared by ultraconcentration of platelets contains multiple growth factors having a chemotactic and mitogenic effect on mesenchymal stem cells and osteoblasts and may play a role in initiating bone healing. The purpose of this retrospective study is to review our results with AGF in lumbar spinal fusions. To date, AGF has been used in 39 patients having lumbar spinal fusion. The study group consisted of the first 19 consecutive cases to allow at least 6 months follow-up. The average follow-up was 13 months (range 6 to 18 months). Follow-up compliance was 91%. There were 7 men and 12 women. Average age was 52 years (range 30-72 years). Nine patients had prior back surgery. There were 8 smokers. AGF was used in posterior (n = 15) or anterior intradiscal (n = 4) fusions. AGF was used with autograft and coraline hydroxyapatite in all posterior fusions, and autograft, coral, and intradiscal spacer (carbon fiber spinal fusion cages or Synthes femoral ring) in intradiscal fusions. Posterior stabilization was used in all cases. Eight cases were single-level fusions, 6 were two-level, and 1 was a three-level fusion. Autologous iliac crest bone graft was taken in 14 cases and local autograft used in 5 cases. Posteriorly, a total of 23 levels were fused; of these, nine were at L5-S1, eight at L4-L5, five at L3-L4, and one at L2-L3. No impending pseudoarthroses were noted on plain radiographic examination at last follow-up visit. Solid fusion was confirmed in 3 patients having routine hardware removal, and in 2 patients who had surgery at an adjacent level. There was one posterior wound infection, which was managed without sequelae. When used as an adjunct to autograft, AGF offers theoretical advantages that need to be examined in controlled studies. Further study is necessary to determine whether coralline hydroxyapatite used as a

  13. A Foundation for Systems Anthropometry: Lumbar/Pelvic Kinematics

    DTIC Science & Technology

    1983-02-01

    Roentgenographic Measurement of Lumbar Intervertebral Disc Height ." Spine , 6(2):154:158. Andriacchi, T., Schultz, A... measured , enabling coupled motion (Wite and Panjabi, 1978), for example, in lateral bending of the lumbar spine , to be investigated. Two different...to seated position. They describe measured positions of the lumbar spine , sacrum, and inncminate with anatomical landmarks important to

  14. [Lumbar disc protrusion in childhood. Description of a case].

    PubMed

    Lins, E; Basedow, H

    1976-02-01

    This is a case of lumbar disc protrusion in a 14 year old girl, with typical symptomatology. Special attention should be called to the rarity of this case. The clinical and myelographic diagnosis showed a lumbar herniation L 4/L5. Treatment was performed by lumbar hemilaminectomie. The post operative controll showed remission of the clinical findings.

  15. Cervical Meningomyelitis After Lumbar Epidural Steroid Injection

    PubMed Central

    Kim, Joon-Sung; Kim, Ji Yeon

    2015-01-01

    Epidural steroid injections (ESI) are a common treatment for back pain management. ESI-related complications have increased with the growing number of procedures. We report a case of cervical meningomyelitis followed by multiple lumbar ESI. A 60-year-old male with diabetes mellitus presented to our hospital with severe neck pain. He had a history of multiple lumbar injections from a local pain clinic. After admission, high fever and elevated inflammatory values were detected. L-spine magnetic resonance imaging (MRI) revealed hematoma in the S1 epidural space. Antibiotic treatment began under the diagnosis of a lumbar epidural abscess. Despite the treatment, he started to complain of weakness in both lower extremities. Three days later, the weakness progressed to both upper extremities. C-spine MRI revealed cervical leptomeningeal enhancement in the medulla oblongata and cervical spinal cord. Removal of the epidural abscess was performed, but there was no neurological improvement. PMID:26161360

  16. New dust belts of Uranus: one ring, two ring, red ring, blue ring.

    PubMed

    de Pater, Imke; Hammel, Heidi B; Gibbard, Seran G; Showalter, Mark R

    2006-04-07

    We compared near-infrared observations of the recently discovered outer rings of Uranus with Hubble Space Telescope results. We find that the inner ring, R/2003 U 2, is red, whereas the outer ring, R/2003 U 1, is very blue. Blue is an unusual color for rings; Saturn's enigmatic E ring is the only other known example. By analogy to the E ring, R/2003 U 1 is probably produced by impacts into the embedded moon Mab, which apparently orbits at a location where nongravitational perturbations favor the survival and spreading of submicron-sized dust. R/2003 U 2 more closely resembles Saturn's G ring, which is red, a typical color for dusty rings.

  17. Saturn's F-Ring

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This narrow-angle camera image of Saturn's F Ring was taken through the Clear filter while at a distance of 6.9 million km from Saturn on 8 November 1980. The brightness variations of this tightly-constrained ring shown here indicate that the ring is less uniform in makeup than the larger rings. JPL managed the Voyager Project for NASA's Office of Space Science

  18. Computed tomography of the postoperative lumbar spine

    SciTech Connect

    Teplick, J.G.; Haskin, M.E.

    1983-11-01

    In the postoperative patient ordinary radiographs of the spine generally add very little information, revealing the usual postoperative bone changes and often postoperative narrowing of the intervertebral space. Myelography may sometimes be informative, showing evidence of focal arachnoiditis or a focal defect at the surgical site. However, the latter finding is difficult to interpret. As experience with high-resolution CT scanning of the lumbar spine has been increasing, it is becoming apparent that this noninvasive and easily performed study can give considerably more information about the postoperative spine than any of the other current imaging methods. About 750 patients with previous lumbar laminectomies had CT scanning within a 28 month period.

  19. DEGENERATIVE STENOSIS OF THE LUMBAR SPINE

    PubMed Central

    Zylbersztejn, Sérgio; Spinelli, Leandro de Freitas; Rodrigues, Nilson Rodinei; Werlang, Pablo Mariotti; Kisaki, Yorito; Rios, Aldemar Roberto Mieres; Bello, Cesar Dall

    2015-01-01

    This paper presents an update on degenerative stenosis of the lumbar spine, which is a common pathological condition among patients over the age of 65 years. The anamnesis and physical examination need to be precise, since radiography often only provides indirect signs. Magnetic resonance imaging is necessary if the symptoms persist. The treatment for lumbar stenosis is a matter of controversy. However, there seems to be some benefit from surgical treatment rather than conservative treatment, such that surgery brings improvements in symptoms and functions for a period of up to two years. PMID:27042635

  20. Mini-open anterior lumbar interbody fusion.

    PubMed

    Gandhoke, Gurpreet S; Ricks, Christian; Tempel, Zachary; Zuckerbraun, Brian; Hamilton, D Kojo; Okonkwo, David O; Kanter, Adam S

    2016-07-01

    In deformity surgery, anterior lumbar interbody fusion provides excellent biomechanical support, creates a broad surface area for arthrodesis, and induces lordosis in the lower lumbar spine. Preoperative MRI, plain radiographs, and, when available, CT scan should be carefully assessed for sacral slope as it relates to pubic symphysis, position of the great vessels (especially at L4/5), disc space height, or contraindication to an anterior approach. This video demonstrates the steps in an anterior surgical procedure with minimal open exposure. The video can be found here: https://youtu.be/r3bC4_vu1hQ .

  1. Comparison of electromyographic activities of lumbar iliocostalis and lumbar multifidus muscles during stabilization exercises in prone, quadruped, and sitting positions

    PubMed Central

    Kelly, Marie; Jacobs, Dee; Wooten, Mary E.; Edeer, Ayse Ozcan

    2016-01-01

    [Purpose] The purposes of this study were: 1) describe a hierarchy of electromyographic activity production, using percentage maximum voluntary contraction of lumbar iliocostalis and lumbar multifidus muscles during prone, quadruped and sitting exercises; and 2) identify optimal recruitment exercises for both lumbar iliocostalis as a global multi-segmental stabilizer and lumbar multifidus as a segmental stabilizer. [Subjects] Twelve healthy volunteers (six male and six female) aged 24 to 45 participated. [Methods] Surface electromyographic activity data were collected bilaterally from lumbar iliocostalis and lumbar multifidus muscles during exercises. [Results] Two-way ANOVA showed that prone extension, and prone alternate arm and leg lifting exercises produce a statistically significant difference in percent maximum voluntary contraction of lumbar iliocostalis and lumbar multifidus bilaterally compared to other exercises. Quadruped alternate arm and leg lifting exercises produce greater activity in lumbar multifidus muscle than sitting exercises [Conclusion] Prone exercises generate the greatest electromyographic activity and may be the most effective exercises for strengthening both lumbar iliocostalis and lumbar multifidus muscles. Quadruped alternate arm and leg lifting produces electromyographic activity at the recommended percent maximum voluntary contraction for training the lumbar multifidus in its role as a segmental stabilizer and is an effective training exercise for this goal. PMID:27821968

  2. On certain Hecke rings

    PubMed Central

    Evens, Sam; Bressler, Paul

    1987-01-01

    We examine rings that embed into the smash product of the group algebra of the Weyl group with the field of meromorphic functions on the Cartan subalgebra and are generated by elements that satisfy braid relations. We prove that every such ring is isomorphic to either the Hecke algebra, the nil Hecke ring, or the group algebra of the Weyl group. PMID:16593804

  3. The Jumping Ring Experiment

    ERIC Educational Resources Information Center

    Baylie, M.; Ford, P. J.; Mathlin, G. P.; Palmer, C.

    2009-01-01

    The jumping ring experiment has become central to liquid nitrogen shows given as part of the outreach and open day activities carried out within the University of Bath. The basic principles of the experiment are described as well as the effect of changing the geometry of the rings and their metallurgical state. In general, aluminium rings are…

  4. Rings Around Uranus

    ERIC Educational Resources Information Center

    Maran, Stephen P.

    1977-01-01

    Events leading up to the discovery of the rings of Uranus are described. The methods used and the logic behind the methods are explained. Data collected to prove the existence of the rings are outlined and theories concerning the presence of planetary rings are presented. (AJ)

  5. Soft normed rings.

    PubMed

    Uluçay, Vakkas; Şahin, Mehmet; Olgun, Necati

    2016-01-01

    Molodtsov introduced the concept of soft sets, which can be seen as a new mathematical tool for dealing with uncertainty. In this paper, we initiate the study of soft normed rings by soft set theory. The notions of soft normed rings, soft normed ideals, soft complete normed rings are introduced and also several related properties and examples are given.

  6. Midsagittal anatomy of lumbar lordosis in adult egyptians: MRI study.

    PubMed

    Hegazy, Abdelmonem A; Hegazy, Raafat A

    2014-01-01

    Despite the increasing recognition of the functional and clinical importance of lumbar lordosis, little is known about its description, particularly in Egypt. At the same time, magnetic resonance imaging (MRI) has been introduced as a noninvasive diagnostic technique. The aim of this study was to investigate the anatomy of the lumbar lordosis using midsagittal MRIs. Normal lumbar spine MRIs obtained from 93 individuals (46 males, 47 females; 25-57 years old) were evaluated retrospectively. The lumbar spine curvature and its segments "vertebrae and discs" were described and measured. The lumbar lordosis angle (LLA) was larger in females than in males. Its mean values increased by age. The lumbar height (LH) was longer in males than in females. At the same time, the lumbar breadth (LB) was higher in females than in males. Lumbar index (LI = LB/LH × 100) showed significant gender differences (P < 0.0001). Lordosis was formed by wedging of intervertebral discs and bodies of lower lumbar vertebrae. In conclusion, MRI might clearly reveal the anatomy of the lumbar lordosis. Use of LI in association with LLA could be useful in evaluation of lumbar lordosis.

  7. Saturn's largest ring.

    PubMed

    Verbiscer, Anne J; Skrutskie, Michael F; Hamilton, Douglas P

    2009-10-22

    Most planetary rings in the Solar System lie within a few radii of their host body, because at these distances gravitational accelerations inhibit satellite formation. The best known exceptions are Jupiter's gossamer rings and Saturn's E ring, broad sheets of dust that extend outward until they fade from view at five to ten planetary radii. Source satellites continuously supply the dust, which is subsequently lost in collisions or by radial transport. Here we report that Saturn has an enormous ring associated with its outer moon Phoebe, extending from at least 128R(S) to 207R(S) (Saturn's radius R(S) is 60,330 km). The ring's vertical thickness of 40R(S) matches the range of vertical motion of Phoebe along its orbit. Dynamical considerations argue that these ring particles span the Saturnian system from the main rings to the edges of interplanetary space. The ring's normal optical depth of approximately 2 x 10(-8) is comparable to that of Jupiter's faintest gossamer ring, although its particle number density is several hundred times smaller. Repeated impacts on Phoebe, from both interplanetary and circumplanetary particle populations, probably keep the ring populated with material. Ring particles smaller than centimetres in size slowly migrate inward and many of them ultimately strike the dark leading face of Iapetus.

  8. Current Status of Lumbar Interbody Fusion for Degenerative Spondylolisthesis

    PubMed Central

    TAKAHASHI, Toshiyuki; HANAKITA, Junya; OHTAKE, Yasufumi; FUNAKOSHI, Yusuke; OICHI, Yuki; KAWAOKA, Taigo; WATANABE, Mizuki

    2016-01-01

    Instrumented lumbar fusion can provide immediate stability and assist in satisfactory arthrodesis in patients who have pain or instability of the lumbar spine. Lumbar adjunctive fusion with decompression is often a good procedure for surgical management of degenerative spondylolisthesis (DS). Among various lumbar fusion techniques, lumbar interbody fusion (LIF) has an advantage in that it maintains favorable lumbar alignment and provides successful fusion with the added effect of indirect decompression. This technique has been widely used and represents an advancement in spinal instrumentation, although the rationale and optimal type of LIF for DS remains controversial. We evaluated the current status and role of LIF in DS treatment, mainly as a means to augment instrumentation. We addressed the basic concept of LIF, its indications, and various types including minimally invasive techniques. It also has acceptable biomechanical features, and offers reconstruction with ideal lumbar alignment. Postsurgical adverse events related to each LIF technique are also addressed. PMID:27169496

  9. On the solar dust ring(s)

    NASA Astrophysics Data System (ADS)

    Mukai, T.

    Based on a mechanism to form the solar dust ring, it is proved that the observed peak in infrared F-corona cannot be explained by silicate type grains alone. Preliminary analysis on the recent infrared data of the F-corona by Maihara et al. (1984) has suggested that the ring particles have different physical properties compared with the dust grains, which produce the background F-corona.

  10. Lumbar spine anomalies in a pycnodysostosis case.

    PubMed

    Beguiristain, J L; Arriola, F J; Leyes, M

    1995-01-01

    We report a case of pycnodysostosis in which several clefts in the laminas, interarticular parts, and pedicles of the whole lumbar spine were revealed for the first time on CT. We review similar findings in the literature, and discuss their pathogenesis.

  11. Multiple lumbar arachnoid cysts. Case report.

    PubMed

    Pappalardo, S; Cassarino, A; Braidotti, P

    1986-09-01

    Arachnoid cysts are a rare cause of compression of the contents of the lumbar spinal canal; in the literature only about 100 cases are reported. The various methods of diagnosis are discussed in the light of a recent case observed by the authors.

  12. [Lumbar pain and bilateral adrenal masses].

    PubMed

    García, Elena; Sánchez, Raquel; Martínez, Guillermo; Bernal, Carmen; Calatayud, M; Partida, M; Hawkins, Federico

    2009-05-01

    Many problems may arise when defining whether adrenal lesions are primary to the adrenal glands or represent other tissue, whether they are benign or malignant and whether they are functioning or nonfunctioning. Adrenal imaging complements the clinical and hormonal evaluation of these patients. We present a patient with lumbar pain and bilateral adrenal masses.

  13. Dust and Planetary Rings

    NASA Astrophysics Data System (ADS)

    Siddiqui, Muddassir

    ABSTRACT Space is not empty it has comic radiations (CMBR), dust etc. Cosmic dust is that type of dust which is composed of particles in space which vary from few molecules to 0.1micro metres in size. This type of dust is made up of heavier atoms born in the heart of stars and supernova. Mainly it contains dust grains and when these dust grains starts compacting then it turns to dense clouds, planetary ring dust and circumstellar dust. Dust grains are mainly silicate particles. Dust plays a major role in our solar system, for example in zodiacal light, Saturn's B ring spokes, planetary rings at Jovian planets and comets. Observations and measurements of cosmic dust in different regions of universe provide an important insight into the Universe's recycling processes. Astronomers consider dust in its most recycled state. Cosmic dust have radiative properties by which they can be detected. Cosmic dusts are classified as intergalactic dusts, interstellar dusts and planetary rings. A planetary ring is a ring of cosmic dust and other small particles orbiting around a planet in flat disc shape. All of the Jovian planets in our solar system have rings. But the most notable one is the Saturn's ring which is the brightest one. In March 2008 a report suggested that the Saturn's moon Rhea may have its own tenuous ring system. The ring swirling around Saturn consists of chunks of ice and dust. Most rings were thought to be unstable and to dissipate over course of tens or hundreds of millions of years but it now appears that Saturn's rings might be older than that. The dust particles in the ring collide with each other and are subjected to forces other than gravity of its own planet. Such collisions and extra forces tend to spread out the rings. Pluto is not known to have any ring system but some Astronomers believe that New Horizons probe might find a ring system when it visits in 2015.It is also predicted that Phobos, a moon of Mars will break up and form into a planetary ring

  14. Slowing of Vortex Rings

    NASA Astrophysics Data System (ADS)

    Donnelly, Russell; Bolster, Diogo; Hershberger, Robert

    2008-11-01

    We have investigated the slowing of vortex rings in water which are created with very thin cores. We find that these rings propagate with no measurable change in diameter or core size. The drag appears to be the result of viscous forces on the core. A simple model for this drag describes experimental data in terms of a drag coefficient, which depends only on Reynolds number. Barenghi's group at Newcastle found that the translational velocity of a ring in an inviscid fluid perturbed by Kelvin waves decreases with increasing amplitude of Kelvin waves. This suggests that the velocity of vortex rings in a viscous fluid may well depend on the amplitude of Kelvin waves at the time of formation. Rings with substantial amplitude of Kelvin waves will be expected to move more slowly than rings with little or no Kelvin wave amplitude. We present experimental data confirming this suggestion.

  15. Radioactive gold ring dermatitis

    SciTech Connect

    Miller, R.A.; Aldrich, J.E. )

    1990-08-01

    A superficial squamous cell carcinoma developed in a woman who wore a radioactive gold ring for more than 30 years. Only part of the ring was radioactive. Radiation dose measurements indicated that the dose to basal skin layer was 2.4 Gy (240 rad) per week. If it is assumed that the woman continually wore her wedding ring for 37 years since purchase, she would have received a maximum dose of approximately 4600 Gy.

  16. Saturn's E ring revisited

    NASA Astrophysics Data System (ADS)

    Feibelman, W. A.; Klinglesmith, D. A.

    1980-07-01

    Images of the E ring of Saturn obtained by the image processing of photographs of the 1966 edge-on presentation of the planet's ring plane are presented. Two methods of image enhancement were used: scanning with an image quantizer operated in the derivative mode to enhance contrast and computerized subtraction of a circularly symmetric image of the overexposed Saturn disk. Further photographic and CCD observation confirming the existence of the ring extending to twice the diameter of the A ring, which was not detected by the Pioneer 11 imaging photopolarimeter, is indicated.

  17. Jupiter's Ring Halo

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A mosaic of four images taken through the clear filter (610 nanometers) of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft on November 8, 1996, at a resolution of approximately 46 kilometers (km) per picture element (pixel) along the rings; however, because the spacecraft was only about 0.5 degrees above the ring plane, the image is highly foreshortened in the vertical direction. The images were obtained when Galileo was in Jupiter's shadow peering back toward the Sun; the ring was approximately 2,300,000 kilometers (km) away. The arc on the far right of the image is produced by sunlight scattered by small particles comprising Jupiter's upper atmospheric haze. The ring also efficiently scatters light, indicating that much of its brightness is due to particles that are microns or less in diameter. Such small particles are believed to have human-scale lifetimes, i.e., very brief compared to the solar system's age.

    Jupiter's ring system is composed of three parts -- a flat main ring, a lenticular halo interior to the main ring, and the gossamer ring, which lies exterior to the main ring. The near and far arms of Jupiter's main ring extend horizontally across the mosaic, joining together at the ring's ansa, on the far left side of the figure. The near arm of the ring appears to be abruptly truncated close to the planet, at the point where it passes into Jupiter's shadow.

    A faint mist of particles can be seen above and below the main rings; this vertically extended, toroidal 'halo' is unusual in planetary rings, and is probably caused by electromagnetic forces which can push small grains out of the ring plane. Halo material is present across this entire image, implying that it reaches more than 27,000 km above the ring plane. Because of shadowing, the halo is not visible close to Jupiter in the lower right part of the mosaic. In order to accentuate faint features in the image, different brightnesses are shown through color, with the brightest

  18. Effects of lumbar stabilization exercise on functional disability and lumbar lordosis angle in patients with chronic low back pain

    PubMed Central

    Cho, Igsoo; Jeon, Chunbae; Lee, Sangyong; Lee, Daehee; Hwangbo, Gak

    2015-01-01

    [Purpose] This study examined the effects of lumbar stabilization exercises on the functional disability and lumbar lordosis angles in patients with chronic low back pain. [Subjects] The subjects were 30 patients with chronic low back pain divided into a lumbar stabilization exercise group (n = 15) and a conservative treatment group (n = 15). [Methods] The lumbar stabilization exercise and conservative treatment groups performed an exercise program and conservative physical treatment, respectively. Both programs were performed 3 times a week for 6 weeks. The degree of functional disability was assessed by the Oswestry disability index, and lumbar lordosis angles were measured by plain radiography. [Results] The Oswestry disability index decreased significantly in the both groups; however, it was significantly lower in the lumbar stabilization exercise group. The lumbar lordosis angle increased significantly in the lumbar stabilization exercise group after treatment and was also significantly greater than that in the conservative treatment group. [Conclusion] Lumbar stabilization exercise is more effective than conservative treatment for improving functional disability and lumbar lordosis angles. PMID:26180363

  19. Modified spiral wound retaining ring

    NASA Technical Reports Server (NTRS)

    Lawson, A. G. (Inventor)

    1980-01-01

    A spiral wound retaining ring with angled ends is described. The ring is crimped at the same angle as the ring ends to maintain a constant thickness dimension. The angling of the ends of the ring and crimp allow the ends to be positioned closer together while maintaining enough clearance to enable insertion and removal of the ring. By reducing the separation distance between the ends a stronger ring results since the double layer area of the ring is maximized.

  20. Characteristics of PMHS Lumbar Motion Segments in Lateral Shear.

    PubMed

    Sundararajan, Srini; Prasad, Priya; Rouhana, Stephen W; Demetropoulos, Constantine K; Yang, King H; King, Albert I; Nolte, Lutz P

    2005-11-01

    The purpose of this study was to determine the characteristics of eighteen lumbar spine motion segments subjected to lateral shear forces under quasi-static (0.5 mm/s) and dynamic (500 mm/s) test conditions. The quasi-static test was also performed on the lumbar spine of a side impact anthropomorphic test device, the EuroSID-2 (ES-2). In the quasi-static tests, the maximum force before disc-endplate separation in the PMHS lumbar motion segments was 1850 +/- 612 N, while the average linear stiffness of PMHS lumbar motion segments was 323 +/- 126 N/mm. There was a statistically significant difference between the quasi-static (1850 +/- 612 N) and dynamic (2616 +/- 1151 N) maximum shear forces. The ES-2 lumbar spine (149 N/mm) was more compliant than the PMHS lumbar segments under the quasi-static test condition.

  1. [Vascular complications associated with lumbar spinal surgery].

    PubMed

    Riedemann-Wistuba, M; Alonso-Pérez, M; Llaneza-Coto, J M

    2016-01-01

    Although there are currently less invasive techniques available for the treatment of spinal injuries, open surgery is still required in many cases. Vascular injuries occurring during lumbar spine surgery, although uncommon, are of great importance due to their potential gravity. Clinical manifestations vary from an acute hemorrhagic shock that needs urgent treatment to save the patient's life, to insidious injuries or an asymptomatic evolution, and should be studied to choose the best therapeutic alternative. Four cases are reported that represent this range of possibilities and emphasize the importance of a careful surgical technique during lumbar spine interventions, and the need for high clinical suspicion, essential for the early diagnosis of these vascular complications. The current therapeutic options are also discussed.

  2. [Polish nomenclature of lumbar disc disease].

    PubMed

    Radło, Paweł; Smetkowski, Andrzej; Tesiorowski, Maciej

    2014-01-01

    Lumbar disc herniation is one of the most common damage of musculoskeletal system. The incidence of pain of lumbosacral spine is estimated approximately on 60-90% in general population, whereas the incidence of disc herniation in patients experiencing low back pain is about 91%. Despite the high incidence and uncomplicated pathogenesis of disc disease there is a problem with the nomenclature. In the vast majority of cases, the naming confusion stems from ignorance of the etiology of low back pain. Different terminologies: morphological, topographical, Radiological and Clinical are used interchangeably. In addition, diagnosis is presented in a variety of languages: Polish, English and Latin. Moreover, the medical and traditional language are used alternately. The authors found in Polish literature more, than 20 terms to describe lumbar disc herniation. All of these terms in the meaning of the authors are used to determine one pathology--mechanical damage to the intervertebral disc and moving the disc material beyond the anatomical area.

  3. Single incision endoscopic surgery for lumbar hernia.

    PubMed

    Kawaguchi, Masahiko; Ishikawa, Norihiko; Shimizu, Satsuki; Shin, Hisato; Matsunoki, Aika; Watanabe, Go

    2011-01-01

    Single Incision Endoscopic Surgery (SIES) has emerged as a less invasive surgery among laparoscopic surgeries, and this approach for incisional hernia was reported recently. This is the first report of SIES for an incisional lumbar hernia. A 66-year-old Japanese woman was referred to our institution because of a left flank hernia that developed after left iliac crest bone harvesting. A 20-mm incision was created on the left side of the umbilicus and all three trocars (12, 5, and 5 mm) were inserted into the incision. The hernial defect was 14 × 9 cm and was repaired with intraperitoneal onlay mesh and a prosthetic graft. The postoperative course was uneventful. SIES for lumbar hernia offers a safe and effective outcome equivalent compared to laparoscopic surgery. In addition, SIES is less invasive and has a cosmetic benefit.

  4. Diskography outcomes in patients following lumbar diskectomy.

    PubMed

    Siambanes, David; Kposowa, Augustine J; Michelsen, Steven

    2003-08-01

    The results of lumbar diskography at post-diskectomy and nonoperative disk levels in postoperative patients and patients without prior back surgery were reviewed over 3 years. Other possible predictive factors, including disk degeneration (per the Adam's classification), end-point resistance, gender, and age, also were reviewed. The results revealed that no statistically significant association was noted between the presence of a prior diskectomy and the outcome of diskography. However, disk degeneration classified as ruptured and fissured correlated statistically with positive diskography. Additionally, age between 30 and 39 years and male gender were statistically associated with a positive diskogram. Disk levels displaying a poor end point during diskography injection (not amendable to pressurization) were statistically related to ruptured or fissured disk levels and thus positive diskography. Based on these results, the assumption that disabling low-back pain presenting after lumbar procedure is due to diskogenic disease arising from the surgical level is not supported.

  5. Recognition of lumbar disk herniation with NMR

    SciTech Connect

    Chafetz, N.I.; Genant, H.K.; Moon, K.L.; Helms, C.A.; Morris, J.M.

    1983-12-01

    Fifteen nuclear magnetic resonance (NMR) studies of 14 patients with herniated lumbar intervertebral disks were performed on the UCSF NMR imager. Computed tomographic (CT) scans done on a GE CT/T 8800 or comparable scanner were available at the time of NMR scan interpretation. Of the 16 posterior disk ruptures seen at CT, 12 were recognized on NMR. Diminished nucleus pulposus signal intensity was present in all ruptured disks. In one patient, NMR scans before and after chymopapain injection showed retraction of the protruding part of the disk and loss of signal intensity after chemonucleolysis. Postoperative fibrosis demonstrated by CT in one patient and at surgery in another showed intermediate to high signal intensity on NMR, easily distinguishing it from nearby thecal sac and disk. While CT remains the method of choice for evaluation of the patient with suspected lumbar disk rupture, the results of this study suggest that NMR may play a role in evaluating this common clinical problem.

  6. Lumbar discal cyst in an elite athlete.

    PubMed

    Singleton, Alex; Agarwal, Vikas; Casagranda, Bethany; Hughes, Marion A; Rothfus, William E

    2013-01-01

    Our patient, a 22-year-old starting wide receiver for an NCAA Division I football team, presented with low back pain and sciatica. A lumbar-spine MRI without contrast demonstrated findings suspicious for discal cyst. The patient was referred for surgery, and the lesion was resected. The rarity of discal cyst makes it difficult to diagnose because most radiologists are not aware of the entity. An organized approach to diagnosis can facilitate appropriate management.

  7. Congenitally absent lumbar pedicle: a reappraisal

    SciTech Connect

    Wortzman, G.; Steinhardt, M.I.

    1984-09-01

    Three patients who had a diagnosis of congenitally absent lumbar pedicle underwent CT examination. Findings showed that each patient had an aberrant hypoplastic pedicle plus a retroisthmic defect in their ipsilateral lamina rather than an absent pedicle. Axial CT was the diagnostic modality of choice; reformated images were of little value. The differential diagnosis to be considered from the findings of plain film radiography includes pediculate thinning, neoplastic disease, neurofibroma, mesodermal dysplasia associated with neurofibromatosis, and vascular anomalies.

  8. Lumbar nerve root: the enigmatic eponyms.

    PubMed

    Dyck, P

    1984-01-01

    Man's quest for recognition has not escaped the physician, whose contributions to medicine perpetuate his name in print. It is a final grasp for professional immortality, which for men like Imhotep and Hippocrates, has prevailed for millennia. This fervor was particularly evident in the latter 19th century, which created a flurry of eponyms, often two or more physicians publishing the same clinical observation. This article reviews the eponym epidemic as it relates to lumbar radiculopathy.

  9. [Serious thromboembolitic incidents during lumbar spine phlebography].

    PubMed

    Gatti, P; Valat, J P; Videgrain, M

    1983-02-01

    From a series of 400 cases of lumbar spine phlebography by selective catheterisation, 4 serious thrombo-embolic episodes were observed, including 2 cases of severe pulmonary embolism which responded favourably to medical treatment. In 3 cases, risk factors were found (prolonged immobilisation in bed, past history of phlebitis). One case developed severe phlebitis of the lower limbs despite prophylactic treatment with low dose calcium heparin. In the other cases, no anti-coagulant therapy was prescribed before or during the examination.

  10. Effect of Load Carriage on Lumbar Spine Kinematics

    DTIC Science & Technology

    2013-01-01

    markers 14 – 16 , 18 and ground force plates 7 , 18 , 19 to measure body positioning and ground reac- tion forces . These methods approach...data obtained in this setting do not refl ect the state of the lumbar spine in the upright position due to alterations in bone- muscle interactions...lumbar spine might be related to the greater forces acting on inferior levels through the lumbar spine 38 and that IVDs of inferior levels undergo

  11. Contactless Magnetic Slip Ring

    NASA Technical Reports Server (NTRS)

    Kumagai, Hiroyuki (Inventor); Deardon, Joe D. (Inventor)

    1997-01-01

    A contactless magnetic slip ring is disclosed having a primary coil and a secondary coil. The primary and secondary coils are preferably magnetically coupled together, in a highly reliable efficient manner, by a magnetic layered core. One of the secondary and primary coils is rotatable and the contactless magnetic slip ring provides a substantially constant output.

  12. Illustration of Saturn's Rings

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This illustration shows a close-up of Saturn's rings. These rings are thought to have formed from material that was unable to form into a Moon because of tidal forces from Saturn, or from a Moon that was broken up by Saturn's tidal forces.

  13. Birth Control Ring

    MedlinePlus

    ... It? The birth control ring is a soft, flexible, doughnut-shaped ring about 2 inches (5 centimeters) in diameter. It is inserted into the vagina, where it slowly releases hormones — the chemicals the body makes to control organ function — through the vaginal wall into the ...

  14. Steroidal contraceptive vaginal rings.

    PubMed

    Sarkar, N N

    2003-06-01

    The development of steroid-releasing vaginal rings over the past three decades is reviewed to illustrate the role of this device as an effective hormonal contraceptive for women. Vaginal rings are made of polysiloxane rubber or ethylene-vinyl-acetate copolymer with an outer diameter of 54-60 mm and a cross-sectional diameter of 4-9.5 mm and contain progestogen only or a combination of progestogen and oestrogen. The soft flexible combined ring is inserted in the vagina for three weeks and removed for seven days to allow withdrawal bleeding. Progesterone/progestogen-only rings are kept in for varying periods and replaced without a ring-free period. Rings are in various stages of research and development but a few, such as NuvaRing, have reached the market in some countries. Women find this method easy to use, effective, well tolerated and acceptable with no serious side-effects. Though the contraceptive efficacy of these vaginal rings is high, acceptability is yet to be established.

  15. Smoke Ring Physics

    NASA Astrophysics Data System (ADS)

    Huggins, Elisha

    2011-11-01

    The behavior of smoke rings, tornados, and quantized vortex rings in superfluid helium has many features in common. These features can be described by the same mathematics we use when introducing Ampère's law in an introductory physics course. We discuss these common features.

  16. The Fermilab recycler ring

    SciTech Connect

    Martin Hu

    2001-07-24

    The Fermilab Recycler is a permanent magnet storage ring for the accumulation of antiprotons from the Antiproton Source, and the recovery and cooling of the antiprotons remaining at the end of a Tevatron store. It is an integral part of the Fermilab III luminosity upgrade. The following paper describes the design features, operational and commissioning status of the Recycler Ring.

  17. Smoke Ring Physics

    ERIC Educational Resources Information Center

    Huggins, Elisha

    2011-01-01

    The behavior of smoke rings, tornados, and quantized vortex rings in superfluid helium has many features in common. These features can be described by the same mathematics we use when introducing Ampere's law in an introductory physics course. We discuss these common features. (Contains 7 figures.)

  18. EBT ring physics

    SciTech Connect

    Uckan, N.A.

    1980-04-01

    This workshop attempted to evaluate the status of the current experimental and theoretical understanding of hot electron ring properties. The dominant physical processes that influence ring formation, scaling, and their optimal behavior are also studied. Separate abstracts were prepared for each of the 27 included papers. (MOW)

  19. Telemetry carrier ring and support

    NASA Technical Reports Server (NTRS)

    Wakeman, Thomas G. (Inventor)

    1992-01-01

    A telemetry carrier ring for use in a gas turbine engine includes an annular support ring connected to the engine and an annular carrier ring coupled to the support ring, each ring exhibiting different growth characteristics in response to thermal and mechanical loading. The carrier ring is coupled to the support ring by a plurality of circumferentially spaced web members which are relatively thin in an engine radial direction to provide a predetermined degree of radial flexibility. the web members have a circumferential width and straight axial line of action selected to transfer torque and thrust between the support ring and the carrier ring without substantial deflection. The use of the web members with radial flexibility provides compensation between the support ring and the carrier ring since the carrier ring grows at a different rate than the supporting ring.

  20. Etiology of lumbar lordosis and its pathophysiology: a review of the evolution of lumbar lordosis, and the mechanics and biology of lumbar degeneration.

    PubMed

    Sparrey, Carolyn J; Bailey, Jeannie F; Safaee, Michael; Clark, Aaron J; Lafage, Virginie; Schwab, Frank; Smith, Justin S; Ames, Christopher P

    2014-05-01

    The goal of this review is to discuss the mechanisms of postural degeneration, particularly the loss of lumbar lordosis commonly observed in the elderly in the context of evolution, mechanical, and biological studies of the human spine and to synthesize recent research findings to clinical management of postural malalignment. Lumbar lordosis is unique to the human spine and is necessary to facilitate our upright posture. However, decreased lumbar lordosis and increased thoracic kyphosis are hallmarks of an aging human spinal column. The unique upright posture and lordotic lumbar curvature of the human spine suggest that an understanding of the evolution of the human spinal column, and the unique anatomical features that support lumbar lordosis may provide insight into spine health and degeneration. Considering evolution of the skeleton in isolation from other scientific studies provides a limited picture for clinicians. The evolution and development of human lumbar lordosis highlight the interdependence of pelvic structure and lumbar lordosis. Studies of fossils of human lineage demonstrate a convergence on the degree of lumbar lordosis and the number of lumbar vertebrae in modern Homo sapiens. Evolution and spine mechanics research show that lumbar lordosis is dictated by pelvic incidence, spinal musculature, vertebral wedging, and disc health. The evolution, mechanics, and biology research all point to the importance of spinal posture and flexibility in supporting optimal health. However, surgical management of postural deformity has focused on restoring posture at the expense of flexibility. It is possible that the need for complex and costly spinal fixation can be eliminated by developing tools for early identification of patients at risk for postural deformities through patient history (genetics, mechanics, and environmental exposure) and tracking postural changes over time.

  1. Design concepts in lumbar total disc arthroplasty

    PubMed Central

    Bellini, Chiara M.; Zweig, Thomas; Ferguson, Stephen; Raimondi, Manuela T.; Lamartina, Claudio; Brayda-Bruno, Marco; Fornari, Maurizio

    2008-01-01

    The implantation of lumbar disc prostheses based on different design concepts is widely accepted. This paper reviews currently available literature studies on the biomechanics of TDA in the lumbar spine, and is targeted at the evaluation of possible relationships between the aims of TDA and the geometrical, mechanical and material properties of the various available disc prostheses. Both theoretical and experimental studies were analyzed, by a PUBMED search (performed in February 2007, revised in January 2008), focusing on single level TDA. Both semi-constrained and unconstrained lumbar discs seem to be able to restore nearly physiological IAR locations and ROM values. However, both increased and decreased ROM was stated in some papers, unrelated to the clinical outcome. Segmental lordosis alterations after TDA were reported in most cases, for both constrained and unconstrained disc prostheses. An increase in the load through the facet joints was documented, for both semi-constrained and unconstrained artificial discs, but with some contrasting results. Semi-constrained devices may be able to share a greater part of the load, thus protecting the surrounding biological structure from overloading and possible early degeneration, but may be more susceptible to wear. The next level of development will be the biomechanical integration of compression across the motion segment. All these findings need to be supported by long-term clinical outcome studies. PMID:18946684

  2. Minimally Invasive Laminectomy in Spondylolisthetic Lumbar Stenosis

    PubMed Central

    Caralopoulos, Ilias N.; Bui, Cuong J.

    2014-01-01

    Background Degenerative lumbar stenosis associated with spondylolisthesis is common in elderly patients. The most common symptoms are those of neurogenic claudication with leg pain. Surgery is indicated for those who fail conservative management. The generally accepted recommendation is to perform a laminectomy and a fusion at the involved level. Methods We reviewed our results for minimally invasive single-level decompression without fusion performed by the senior author in patients with symptomatic lumbar stenosis with spondylolisthesis with no dynamic instability from 2008 to 2011 at a single institution. Outcomes were measured using the visual analog scale (VAS), Prolo Economic Functional Rating Scale, and revised Oswestry Disability Index (ODI) at initial presentation and at 3-month, 6-month, and 1-year follow-up time points. Results Records for 28 patients (19 males, 9 females) were reviewed. The success rate, defined as improvement in pain and functional outcome without the need for surgical fusion, was 86%. VAS scores decreased by 6.3 points, Prolo scores increased by 3.5 points, and the ODI decreased by 31% at 1 year. All changes were statistically significant. Conclusion Minimally invasive decompression alone can be a reasonable alternative to decompression and fusion for patients with spondylolisthetic lumbar stenosis and neurogenic claudication with leg pain. Decompression without fusion should be considered for older patients and for patients who are not ideal fusion candidates. PMID:24688331

  3. Linear Lumbar Localized Lysis of Elastic Fibers

    PubMed Central

    Tschen, Jaime A.

    2013-01-01

    Background: The absence or loss of elastic fibers in the skin is referred to as dermal elastolysis. Purpose: This paper describes a woman with a distinctive clinical presentation of mid-dermal elastolysis characterized morphologically by multiple horizontal raised bands on the lower back. Methods: A 20-year-old Filipino woman presented with multiple asymptomatic, flesh-colored, raised, firm, linear, cord-like bands on the lumbar area of her back. There were neither similar lesions elsewhere nor a family member with this condition. Results: Microscopic examination of the raised band showed nearly complete absence of elastic fibers in the mid dermis. In contrast, a biopsy of symmetrically located normal-appearing skin showed a uniform distribution of elastic fibers throughout the dermis. Linear lumbar localized elastolysis is a descriptive designation that accurately reflects a correlation of the clinical and pathological changes of this condition. Conclusion: The clinical differential of raised horizontal cord-like bands on the lower back (without a family history of an inherited elastic fiber disorder, a prior history of trauma, or a significant change in weight or exercise habit) includes linear focal elastosis and linear lumbar localized elastolysis. Microscopic evaluation of a Verhoeff-van Gieson stained lesion specimen (which may be accompanied by a biopsy of normal-appearing skin for comparison) will readily differentiate these conditions. The former is usually characterized by increased elastic fibers, whereas the latter, as in this patient, shows a paucity or absence of elastic fibers in the mid dermis. PMID:23882313

  4. Subarachnoid hemorrhage due to retained lumbar drain.

    PubMed

    Guppy, Kern H; Silverthorn, James W; Akins, Paul T

    2011-12-01

    Intrathecal spinal catheters (lumbar drains) are indicated for several medical and surgical conditions. In neurosurgical procedures, they are used to reduce intracranial and intrathecal pressures by diverting CSF. They have also been placed for therapeutic access to administer drugs, and more recently, vascular surgeons have used them to improve spinal cord perfusion during the treatment of thoracic aortic aneurysms. Insertion of these lumbar drains is not without attendant complications. One complication is the shearing of the distal end of the catheter with a resultant retained fragment. The authors report the case of a 65-year-old man who presented with a subarachnoid hemorrhage due to the migration of a retained lumbar drain that sheared off during its removal. To the best of the authors' knowledge, this is the first case of rostral migration of a retained intrathecal catheter causing subarachnoid hemorrhage. The authors review the literature on retained intrathecal spinal catheters, and their findings support either early removal of easily accessible catheters or close monitoring with serial imaging.

  5. Risk Factors for Recurrent Lumbar Disc Herniations

    PubMed Central

    2014-01-01

    The most common complication after lumbar discectomy is reherniation. As the first step in reducing the rate of recurrence, many studies have been conducted to find out the factors that may increase the reherniation risk. Some reported factors are age, sex, the type of lumbar disc herniation, the amount of fragments removed, smoking, alcohol consumption and the length of restricted activities. In this review, the factors studied thus far are summarized, excepting factors which cannot be chosen or changed, such as age or sex. Apart from the factors shown here, many other risk factors such as diabetes, family history, history of external injury, duration of illness and body mass index are considered. Few are agreed upon by all. The reason for the diverse opinions may be that many clinical and biomechanical variables are involved in the prognosis following operation. For the investigation of risk factors in recurrent lumbar disc herniation, large-scale multicenter prospective studies will be required in the future. PMID:24761206

  6. Jupiter's Gossamer Rings Explained.

    NASA Astrophysics Data System (ADS)

    Hamilton, D. P.

    2003-05-01

    Over the past several years, Galileo measurements and groundbased imaging have drastically improved our knowledge of Jupiter's faint ring system. We now recognize that the ring consists of four components: a main ring 7000km wide, whose inner edge blossoms into a vertically-extended halo, and a pair of more tenuous Gossamer rings, one associated with each of the small moons Thebe and Amalthea. When viewed edge on, the Gossamer rings appear as diaphanous disks whose thicknesses agree with the vertical excursions of the inclined satellites from the equatorial plane. In addition, the brightness of each Gossamer ring drops off sharply outside the satellite orbits. These correlations allowed Burns etal (1999, Science, 284, 1146) to argue convincingly that the satellites act as sources of the dusty ring material. In addition, since most material is seen inside the orbits of the source satellites, an inwardly-acting dissipative force such as Poynting-Robertson drag is implicated. The most serious problem with this simple and elegant picture is that it is unable to explain the existence of a faint swath of material that extends half a jovian radius outward from Thebe. A key constraint is that this material has the same thickness as the rest of the Thebe ring. In this work, we identify the mechanism responsible for the outward extension: it is a shadow resonance, first investigated by Horanyi and Burns (1991, JGR, 96, 19283). When a dust grain enters Jupiter's shadow, photoelectric processes shut down and the grain's electric charge becomes more negative. The electromagnetic forces associated with the varying charge cause periodic oscillations in the orbital eccentricity and semimajor axis as the orbital pericenter precesses. This results in a ring which spreads both inward and outward of its source satellite while preserving its vertical thickness - just as is observed for the Thebe ring. Predictions of the model are: i) gaps of micron-sized material interior to Thebe and

  7. Ring chromosome 4.

    PubMed Central

    McDermott, A; Voyce, M A; Romain, D

    1977-01-01

    A mentally and physically retarded boy with a 46,XY,ring (4) (p16q35) chromosome complement is described. Chromosome banding showed that the amount of chromosome material deleted from the ring chromosome 4 was minimal, apparently no more than the telomeres. Chromosomal aberrations appear to be restricted to the production of double-sized dicentric rings, and aneuploidy. The mosiacism resulting from the behavioural peculiarities of ring chromosomes is described as dynamic mosaicism. It is suggested that the clinical features associated with this ring chromosome are more likely to be the result of the effects of a diploid/monosomy 4/polysomy 4 mosaicism than to the deficiency of the telomeric regions of the chromosome. Images PMID:881718

  8. Jupiter's Rings: Sharpest View

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The New Horizons spacecraft took the best images of Jupiter's charcoal-black rings as it approached and then looked back at Jupiter. The top image was taken on approach, showing three well-defined lanes of gravel- to boulder-sized material composing the bulk of the rings, as well as lesser amounts of material between the rings. New Horizons snapped the lower image after it had passed Jupiter on February 28, 2007, and looked back in a direction toward the sun. The image is sharply focused, though it appears fuzzy due to the cloud of dust-sized particles enveloping the rings. The dust is brightly illuminated in the same way the dust on a dirty windshield lights up when you drive toward a 'low' sun. The narrow rings are confined in their orbits by small 'shepherding' moons.

  9. Kinematic analysis of dynamic lumbar motion in patients with lumbar segmental instability using digital videofluoroscopy

    PubMed Central

    Maroufi, Nader; Behtash, Hamid; Zekavat, Hajar; Parnianpour, Mohamad

    2009-01-01

    The study design is a prospective, case–control. The aim of this study was to develop a reliable measurement technique for the assessment of lumbar spine kinematics using digital video fluoroscopy in a group of patients with low back pain (LBP) and a control group. Lumbar segmental instability (LSI) is one subgroup of nonspecific LBP the diagnosis of which has not been clarified. The diagnosis of LSI has traditionally relied on the use of lateral functional (flexion–extension) radiographs but use of this method has proven unsatisfactory. Fifteen patients with chronic low back pain suspected to have LSI and 15 matched healthy subjects were recruited. Pulsed digital videofluoroscopy was used to investigate kinematics of lumbar motion segments during flexion and extension movements in vivo. Intersegmental linear translation and angular displacement, and pathway of instantaneous center of rotation (PICR) were calculated for each lumbar motion segment. Movement pattern of lumbar spine between two groups and during the full sagittal plane range of motion were analyzed using ANOVA with repeated measures design. Intersegmental linear translation was significantly higher in patients during both flexion and extension movements at L5–S1 segment (p < 0.05). Arc length of PICR was significantly higher in patients for L1–L2 and L5–S1 motion segments during extension movement (p < 0.05). This study determined some kinematic differences between two groups during the full range of lumbar spine. Devices, such as digital videofluoroscopy can assist in identifying better criteria for diagnosis of LSI in otherwise nonspecific low back pain patients in hope of providing more specific treatment. PMID:19727854

  10. Percutaneous endoscopic transforaminal lumbar spinal canal decompression for lumbar spinal stenosis

    PubMed Central

    Wen, Bingtao; Zhang, Xifeng; Zhang, Lin; Huang, Peng; Zheng, Guoquan

    2016-01-01

    Abstract This study aimed to evaluate the safety and curative effect of percutaneous endoscopic transforaminal lumbar spinal canal decompression in the treatment of lumbar spinal stenosis. This retrospective study recruited 64 patients with lumbar spinal stenosis who underwent percutaneous endoscopic lumbar spinal canal decompression via surgical approach of posterolateral intervertebral foramen. The postoperation neurological function and pain status were evaluated by the visual analog scale (VAS) score of pain and the Oswestry disability index (ODI), and the patient satisfaction was evaluated according to the MacNab outcome criteria. The data, including preoperative comorbidities, operation time, the quantity of bleeding, bed rest time, and intraoperative and postoperative complications, were recorded. The mean operation time was 78 min, the mean quantity of bleeding was 20 mL and bed rest time was 6 h to 3 days. All patients were followed-up for 4 months to 5 years. The mean preoperative VAS score was 7.7 ± 1.2, while postoperative 3 months, 6 months, and final follow-up VAS scores were 2.8 ± 0.7, 2.1 ± 0.6, and 0.8 ± 0.6, respectively (P < 0.001). The mean preoperative ODI score was 72.4 ± 1.2, while postoperative 3 months, 6 months, and final follow-up ODI scores were 29.7 ± 4.9, 23.9 ± 4.0, and 12.5 ± 3.9, respectively (P < 0.001). The excellent and good rate reached 73.4% at the final follow-up. The percutaneous endoscopic transforaminal lumbar spinal canal decompression is an easy, safe, and effective minimally invasive surgery for patients with lumbar spinal stenosis. PMID:27977571

  11. The Effects of Stretching with Lumbar Traction on VAS and Oswestry Scales of Patients with Lumbar 4–5 Herniated Intervertebral Disc

    PubMed Central

    Yang, Hae-sun; Yoo, Won-gyu

    2014-01-01

    [Purpose] This study investigated the effect of stretching with lumbar traction on VAS and Oswestry scale scores of lumbar 4–5 herniated intervertebral disc (HIVD) patients. [Subjects] We recruited 20 lumbar 4–5 HIVD patients. [Methods] We performed stretching with lumbar traction for lumbar 4–5 HIVD patients during 4 weeks. The VAS and Oswestry scales were measured before and 4 weeks after the intervention. [Results] The results showed a significant decrease in VAS scale scores for stretching with lumbar traction in lumbar 4–5 HIVD patients, from 18±1.29 to 2.1±1.35. The Oswestry scale scores also decreased significantly, from 20.35±2.01 to 3.5±2.84, after stretching with lumbar traction. [Conclusion] Thus, we suggest stretching with lumbar traction for lumbar 4–5 HIVD patients. PMID:25140094

  12. Lumbar discal cyst with spontaneous regression and subsequent occurrence of lumbar disc herniation.

    PubMed

    Takeshima, Yasuhiro; Takahashi, Toshiyuki; Hanakita, Junya; Watanabe, Mizuki; Kitahama, Yoshihiro; Kuraishi, Keita; Uesaka, Toshio; Minami, Manabu; Nakase, Hiroyuki

    2011-01-01

    A 39-year-old man presented with an extremely rare discal cyst at the L3-4 level manifesting as a left L4 radiculopathy. Two months after onset, he suffered right L4 radiculopathy with new lumbar disc protrusion. Five months after medical treatment, the patient's symptoms improved, and the discal cyst showed complete regression on magnetic resonance imaging. Most cases of discal cyst are surgically treated, with only two previous cases of spontaneous regression. The present case suggests clinical and radiological recovery of symptomatic lumbar discal cyst can be obtained by only conservative therapy.

  13. The Enceladus Ring

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] The Enceladus Ring (labeled)

    This excellent view of the faint E ring -- a ring feature now known to be created by Enceladus -- also shows two of Saturn's small moons that orbit within the ring, among a field of stars in the background.

    The E ring extends from three to eight Saturn radii -- about 180,000 kilometers (118,000 miles) to 482,000 kilometers (300,000 miles). Its full extent is not visible in this view.

    Calypso (22 kilometers, or 14 miles across) and Helene (32 kilometers, or 20 miles across) orbit within the E ring's expanse. Helene skirts the outer parts of the E ring, but here it is projected in front of a region deeper within the ring.

    Calypso and Helene are trojan satellites, or moons that orbit 60 degrees in front or behind a larger moon. Calypso is a Tethys trojan and Helene is a trojan of Dione.

    An interesting feature of note in this image is the double-banded appearance of the E-ring, which is created because the ring is somewhat fainter in the ringplane than it is 500-1,000 kilometers (300-600 miles) above and below the ringplane. This appearance implies that the particles in this part of the ring have nonzero inclinations (a similar affect is seen in Jupiter's gossamer ring). An object with a nonzero inclination does not orbit exactly at Saturn's ringplane. Instead, its orbit takes it above and below the ringplane. Scientists are not entirely sure why the particles should have such inclinations, but they are fairly certain that the reason involves Enceladus.

    One possible explanation is that all the E ring particles come from the plume of icy material that is shooting due south out of the moon's pole. This means all of the particles are created with a certain velocity out of the ringplane, and then they orbit above and below that plane.

    Another possible explanation is that Enceladus produces particles with a range of speeds, but the moon gravitationally

  14. Evaluation of ABM/P-15 versus autogenous bone in an ovine lumbar interbody fusion model

    PubMed Central

    Sherman, Blake P.; Lindley, Emily M.; Turner, A. Simon; Seim III, Howard B.; Benedict, James; Burger, Evalina L.

    2010-01-01

    A prospective, randomized study was performed in an ovine model to compare the efficacy of an anorganic bovine-derived hydroxyapatite matrix combined with a synthetic 15 amino acid residue (ABM/P-15) in facilitating lumbar interbody fusion when compared with autogenous bone harvested from the iliac crest. P-15 is a biomimetic to the cell-binding site of Type-I collagen for bone-forming cells. When combined with ABM, it creates the necessary scaffold to initiate cell invasion, binding, and subsequent osteogenesis. In this study, six adult ewes underwent anterior-lateral interbody fusion at L3/L4 and L4/L5 using PEEK interbody rings filled with autogenous bone at one level and ABM/P-15 at the other level and no additional instrumentation. Clinical CT scans were obtained at 3 and 6 months; micro-CT scans and histomorphometry analyses were performed after euthanization at 6 months. Clinical CT scan analysis showed that all autograft and ABM/P-15 treated levels had radiographically fused outside of the rings at the 3-month study time point. Although the clinical CT scans of the autograft treatment group showed significantly better fusion within the PEEK rings than ABM/P-15 at 3 months, micro-CT scans, clinical CT scans, and histomorphometric analyses showed there were no statistical differences between the two treatment groups at 6 months. Thus, ABM/P-15 was as successful as autogenous bone graft in producing lumbar spinal fusion in an ovine model, and it should be further evaluated in clinical studies. PMID:20694847

  15. Evaluation of ABM/P-15 versus autogenous bone in an ovine lumbar interbody fusion model.

    PubMed

    Sherman, Blake P; Lindley, Emily M; Turner, A Simon; Seim, Howard B; Benedict, James; Burger, Evalina L; Patel, Vikas V

    2010-12-01

    A prospective, randomized study was performed in an ovine model to compare the efficacy of an anorganic bovine-derived hydroxyapatite matrix combined with a synthetic 15 amino acid residue (ABM/P-15) in facilitating lumbar interbody fusion when compared with autogenous bone harvested from the iliac crest. P-15 is a biomimetic to the cell-binding site of Type-I collagen for bone-forming cells. When combined with ABM, it creates the necessary scaffold to initiate cell invasion, binding, and subsequent osteogenesis. In this study, six adult ewes underwent anterior-lateral interbody fusion at L3/L4 and L4/L5 using PEEK interbody rings filled with autogenous bone at one level and ABM/P-15 at the other level and no additional instrumentation. Clinical CT scans were obtained at 3 and 6 months; micro-CT scans and histomorphometry analyses were performed after euthanization at 6 months. Clinical CT scan analysis showed that all autograft and ABM/P-15 treated levels had radiographically fused outside of the rings at the 3-month study time point. Although the clinical CT scans of the autograft treatment group showed significantly better fusion within the PEEK rings than ABM/P-15 at 3 months, micro-CT scans, clinical CT scans, and histomorphometric analyses showed there were no statistical differences between the two treatment groups at 6 months. Thus, ABM/P-15 was as successful as autogenous bone graft in producing lumbar spinal fusion in an ovine model, and it should be further evaluated in clinical studies.

  16. Earth: A Ringed Planet?

    NASA Astrophysics Data System (ADS)

    Hancock, L. O.; Povenmire, H.

    2010-12-01

    Among the most beautiful findings of the Space Age have been the discoveries of planetary rings. Not only Saturn but also Jupiter, Uranus and Neptune have rings; Saturn’s ring system has structures newly discovered; even Saturn's moon Rhea itself has a ring. All these are apparently supplied by material from the planetary moons (Rhea's ring by Rhea itself). The question naturally arises, why should the Earth not have a ring, and on the other hand, if it does, why has it not been observed? No rings have yet been observed in the inner solar system, but after all, rings in the inner solar system might simply tend to be fainter and more transient than those of the outer solar system: the inner solar system is more affected by the solar wind, and the Sun’s perturbing gravitational influence is greater. J.A. O’Keefe first suggested (1980) that Earth might have a ring system of its own. An Earth ring could account for some climate events. O’Keefe remarked that formation or thickening of a ring system in Earth’s equatorial plane could drive glaciation by deepening the chill of the winter hemisphere. (It is very well established that volcanic dust is an effective agent for the extinction of sunlight; this factor can be overwhelmingly apparent in eclipse observations.) O’Keefe died in 2000 and the speculation was not pursued, but the idea of an Earth ring has a prima facie reasonableness that calls for its renewed consideration. The program of this note is to hypothesize that, as O’Keefe proposed: (a) an Earth ring system exists; (b) it affects Earth's weather and climate; (c) the tektite strewn fields comprise filaments of the ring fallen to Earth's surface on various occasions of disturbance by comets or asteroids. On this basis, and drawing on the world's weather records, together with the Twentieth Century Reanalysis by NCEP/CIRES covering the period 1870-2010 and the geology of the tektite strewn fields, we herein propose the hypothesized Earth ring

  17. Seal ring installation tool

    NASA Technical Reports Server (NTRS)

    Haselmaier, L. Haynes (Inventor)

    2004-01-01

    A seal ring tool that allows an installer to position a primary seal ring between hub ends of pipe flanges that are being assembled together. The tool includes a pivoting handle member and extension arms attached to the pivoting handle member. The ends of the arms have side indentation type longitudinal grooves angled toward one another for holding the primary seal ring in place between the hubs of respective pipes that are to be attached together. The arms of the tool can also have flat sides that can be used to abut against an optional second larger seal that is supported within a groove in one of the hub ends so that the second hub end can then be moved against the other side of the primary seal ring. Once the seal ring is positioned between the pipe hubs, the pipe hubs can be moved about the seal ring due to the flat sides of the arms of the tool. The tool eliminates the chances of damaging and contaminating seal rings being installed within pipe hubs that are being attached to one another.

  18. Dynamics of the Uranian Rings

    NASA Technical Reports Server (NTRS)

    Dermott, S. F.

    1984-01-01

    Some of the problems of the shepherding satellite model of Goldreich ant tremaine are discussed. The following topics are studied: (1) optical depths of the all the observed narrow rings; (2) satellite and ring separation timescales; (3) ring edge sharpness; (4) shock formation in narrow rings; (5) the existence of small satellites near the Uranian rings; and (6) the apse and node alignments of the eccentric and inclined rings.

  19. Heavy ion storage rings

    SciTech Connect

    Schuch, R.

    1987-01-01

    A brief overview of synchrotron storage rings for heavy ions, which are presently under construction in different accelerator laboratories is given. Ions ranging from protons up to uranium ions at MeV/nucleon energies will be injected into these rings using multiturn injection from the accelerators available or being built in these laboratories. After injection, it is planned to cool the phase space distribution of the ions by merging them with cold electron beams or laser beams, or by using stochastic cooling. Some atomic physics experiments planned for these rings are presented.

  20. Alternative parallel ring protocols

    NASA Technical Reports Server (NTRS)

    Mukkamala, R.; Foudriat, E. C.; Maly, Kurt J.; Kale, V.

    1990-01-01

    Communication protocols are know to influence the utilization and performance of communication network. The effect of two token ring protocols on a gigabit network with multiple ring structure is investigated. In the first protocol, a mode sends at most one message on receiving a token. In the second protocol, a mode sends all the waiting messages when a token is received. The behavior of these protocols is shown to be highly dependent on the number of rings as well as the load in the network.

  1. Supernumerary small ring chromosome.

    PubMed Central

    Kaffe, S; Kim, H J; Hsu, L Y; Brill, C B; Hirschhorn, K

    1977-01-01

    A supernumerary small ring chromosome was found in 30% of cultured peripheral leucocytes and 50% of skin fibroblasts in a 6-year-old boy with mild mental retardation and midline cleft palate. The extra chromosome appeared to carry a densely staining region on Giemsa banding. The banding patterns of the remaining 46 chromosomes were normal. C banding indicated that the ring chromosome contained mainly centromeric constitutive heterochromatin. Chromosome analysis of both parents showed normal karyotypes by both conventional and banding techniques; thus the origin of the ring chromosome could not be determined. Images PMID:604496

  2. Theodolite Ring Lights

    NASA Technical Reports Server (NTRS)

    Clark, David

    2006-01-01

    Theodolite ring lights have been invented to ease a difficulty encountered in the well-established optical-metrology practice of using highly reflective spherical tooling balls as position references. A theodolite ring light produces a more easily visible reflection and eliminates the need for an autocollimating device. A theodolite ring light is a very bright light source that is well centered on the optical axis of the instrument. It can be fabricated, easily and inexpensively, for use on a theodolite or telescope of any diameter.

  3. Relief of Lumbar Symptoms After Cervical Decompression in Patients with Tandem Spinal Stenosis Presenting with Primarily Lumbar Pain

    PubMed Central

    Felbaum, Daniel R; Stewart, Jeffrey J; Sandhu, Faheem A

    2016-01-01

    Objective: Tandem cervical and lumbar spinal stenosis (TSS) is classically described as intermittent claudication, gait disturbance, and clinical findings of mixed myelopathy and polyradiculopathy. Rarely, patients can present with TSS manifesting in isolated lumbar pain. Several reports have demonstrated improved lumbar back pain and radiculopathy after decompressive cervical spine procedures. We present six patients with dramatic resolution of lumbar spine related symptoms after decompression of the cervical spinal cord despite presenting solely with lower back complaints. Methods: Clinical records of the senior author (F.A.S.) gathered from April 2006 to March 2013 were retrospectively reviewed identifying six patients presenting solely with lumbar symptoms and diagnosed with TSS based on history and physical examination. Results: Six patients with a mean age of 55 (range 39 to 60) presented with solely lower back symptoms and clinical findings suspicious for TSS. Mean follow-up time for all patients was 12 months (range three to 27 months, median 11.5 months). Three patients underwent a cervical procedure as the principal operation, while the remainder had the lumbar spine decompressed initially. All patients that underwent a cervical procedure initially experienced a dramatic decrease or complete resolution of their preoperative lower back pain and radiculopathy (mean preoperative VAS of 6.7 vs. 3.7 postoperative). The remainder of patients with persistent lumbar symptoms resolved after a subsequent cervical operation. Conclusion: Patients presenting with lumbar symptoms out of proportion to imaging require further investigation. We highlight the resolution of lumbar symptoms after a cervical procedure in a select group of patients presenting with lone lower back complaints. In patients presenting with symptoms disproportionate to lumbar imaging, treatment of cervical pathology may provide robust long-term relief of the initial lumbar-related presentation

  4. Lumbar-pelvic coordination in the sitting position.

    PubMed

    Kasahara, Satoshi; Miyamoto, Kenji; Takahashi, Mitsuhiko; Yamanaka, Masanori; Takeda, Naoki

    2008-08-01

    This study assessed the relationship of each movement direction on the lumbar spine and on the pelvis in regards to lumbar-pelvic coordination in the sitting position. Lumbar and pelvic motions were recorded using a flexible electrogoniometer in 12 healthy subjects during two different tasks in the sitting position. The coordination of the lumbar spine and pelvis was evaluated using the ratio of lumbar and pelvic angles (L/P ratio hereafter) in three motion phases. There were significant differences in the L/P ratio values between during the "forward bending" and "rising from a forward flexed position" phases (P<0.01). The L/P ratio value ( approximately -0.7) was consistent during the movement from an erect to a slumped sitting position as the lumbar spine and pelvis moved in opposing directions. This study shows that lumbar-pelvic coordination occurs in the sitting position. Lumbar-pelvic coordination is confirmed even if the movement tasks are different in the sitting position, and these findings show that aspects of a particular movement are dependent on the given movement task. These findings may provide greater insight into the kinematic changes involved in lumber-pelvic coordination, and help clinicians implement sitting exercises conducive to the independence of the patient.

  5. 49 CFR 572.115 - Lumbar spine and pelvis.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Lumbar spine and pelvis. 572.115 Section 572.115... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Side Impact Hybrid Dummy 50th Percentile Male § 572.115 Lumbar spine and pelvis. The specifications and test procedure for...

  6. Lumbar discal cyst as a cause of radiculopathy: case report.

    PubMed

    Cho, Newton; Keith, Julia; Pirouzmand, Fahard

    2016-12-01

    Lumbar discal cysts are rare entities causing radicular pain with unknown etiologies. We report a case of a 42-year-old man who developed radiculopathy secondary to a lumbar discal cyst. Our case sheds some light on anatomy, possible etiological association and clinical course which can help management.

  7. 49 CFR 572.85 - Lumbar spine flexure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Lumbar spine flexure. (a) When subjected to continuously applied force in accordance with paragraph (b... degrees at a force level of not less than 18 pounds and not more than 22 pounds, and straighten upon removal of the force to within 5 degrees of its initial position. (b) Test procedure. (1) The lumbar...

  8. 49 CFR 572.85 - Lumbar spine flexure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Lumbar spine flexure. (a) When subjected to continuously applied force in accordance with paragraph (b... degrees at a force level of not less than 18 pounds and not more than 22 pounds, and straighten upon removal of the force to within 5 degrees of its initial position. (b) Test procedure. (1) The lumbar...

  9. Iohexol versus metrizamide for lumbar myelography: double-blind trial

    SciTech Connect

    Gabrielsen, T.O.; Gebarski, S.S.; Knake, J.E.; Latack, J.T.; Yang, P.J.; Hoff, J.T.

    1984-05-01

    Lumbar myelography was performed in 50 patients; 25 received iohexol and 25 received metrizamide. The two media produced radiographs of equal quality. However, iohexol is stable in solution, while metrizamide is not. Further, markedly less morbidity resulted from iohexol. These features indicate that iohexol may be superior to metrizamide as a contrast agent for lumbar myelography.

  10. Saturn's dynamic D ring

    USGS Publications Warehouse

    Hedman, M.M.; Burns, J.A.; Showalter, M.R.; Porco, C.C.; Nicholson, P.D.; Bosh, A.S.; Tiscareno, M.S.; Brown, R.H.; Buratti, B.J.; Baines, K.H.; Clark, R.

    2007-01-01

    The Cassini spacecraft has provided the first clear images of the D ring since the Voyager missions. These observations show that the structure of the D ring has undergone significant changes over the last 25 years. The brightest of the three ringlets seen in the Voyager images (named D72), has transformed from a narrow, <40-km wide ringlet to a much broader and more diffuse 250-km wide feature. In addition, its center of light has shifted inwards by over 200 km relative to other features in the D ring. Cassini also finds that the locations of other narrow features in the D ring and the structure of the diffuse material in the D ring differ from those measured by Voyager. Furthermore, Cassini has detected additional ringlets and structures in the D ring that were not observed by Voyager. These include a sheet of material just interior to the inner edge of the C ring that is only observable at phase angles below about 60??. New photometric and spectroscopic data from the ISS (Imaging Science Subsystem) and VIMS (Visual and Infrared Mapping Spectrometer) instruments onboard Cassini show the D ring contains a variety of different particle populations with typical particle sizes ranging from 1 to 100 microns. High-resolution images reveal fine-scale structures in the D ring that appear to be variable in time and/or longitude. Particularly interesting is a remarkably regular, periodic structure with a wavelength of ??? 30 ?? km extending between orbital radii of 73,200 and 74,000 km. A similar structure was previously observed in 1995 during the occultation of the star GSC5249-01240, at which time it had a wavelength of ??? 60 ?? km. We interpret this structure as a periodic vertical corrugation in the D ring produced by differential nodal regression of an initially inclined ring. We speculate that this structure may have formed in response to an impact with a comet or meteoroid in early 1984. ?? 2006 Elsevier Inc. All rights reserved.

  11. Ultrasonic Newton's rings

    SciTech Connect

    Hsu, D.K. ); Dayal, V. )

    1992-03-09

    Interference fringes due to bondline thickness variation were observed in ultrasonic scans of the reflected echo amplitude from the bondline of adhesively joined aluminum skins. To demonstrate that full-field interference patterns are observable in point-by-point ultrasonic scans, an optical setup for Newton's rings was scanned ultrasonically in a water immersion tank. The ultrasonic scan showed distinct Newton's rings whose radii were in excellent agreement with the prediction.

  12. Bending the Rings

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Saturn's rings appear strangely warped in this view of the rings seen through the upper Saturn atmosphere.

    The atmosphere acts like a lens in refracting (bending) the light reflected from the rings. As the rings pass behind the overexposed limb (edge) of Saturn as seen from Cassini, the ring structure appears to curve downward due to the bending of the light as it passes through the upper atmosphere.

    This image was obtained using a near-infrared filter. The filter samples a wavelength where methane gas does not absorb light, thus making the far-off rings visible through the upper atmosphere.

    By comparing this image to similar ones taken using filters where methane gas does absorb, scientists can estimate the vertical profile of haze and the abundance of methane in Saturn's high atmosphere.

    The image was taken in visible light with the Cassini spacecraft narrow-angle camera on April 14, 2005, through a filter sensitive to wavelengths of infrared light centered at 938 nanometers and at a distance of approximately 197,000 kilometers (123,000 miles) from Saturn. The image scale is 820 meters (2,680 feet) per pixel.

  13. Lumbar lordosis in osteoporosis and in osteoarthritis

    PubMed Central

    Papadokostakis, Georgios; Stergiopoulos, Konstantinos; Kampanis, Nikos; Katonis, Pavlos

    2008-01-01

    The curvature of the lumbar spine and the risk of developing either osteoporosis (OP) or osteoarthritis (OA) are influenced by many common factors. The aim of this study is to determine whether lumbar lordosis is different between patients with either disease and healthy persons. A cross-sectional, blinded, controlled design was implemented. One hundred and twelve postmenopausal women were evaluated for bone mineral density as well as undergoing spinal radiography. Lordosis measurement was performed with Cobb’s method. The sample was divided in four groups: patients with OP (n = 34, L1–L5 = 40.7°, L1–S1 = 54.1°), patients with OA (n = 29, L1–L5 = 38°, L1–S1 = 52.3°), patients with both diseases (n = 20, L1–L5 = 41.8°, L1–S1 = 52.3°) and controls (n = 29, L1–L5 = 38.6°, L1–S1 = 51.8°). For all participants age, height, weight, body mass index, physical activity level and basal metabolic rate were measured and recorded. The results revealed that although the four groups have significant constitutional differences, lumbar lordosis was comparable between them. The reasons for the lack of association are discussed. PMID:19089464

  14. Symptomatic lumbar spinal arachnoiditis: fact or fallacy?

    PubMed

    Petty, P G; Hudgson, P; Hare, W S

    2000-09-01

    It is generally accepted that chronic adhesive lumbar arachnoiditis is a cause of symptoms, notably back pain and/or pain (of almost any type, not necessarily 'anatomical') in the lower limbs, although there is no clearly defined clinical pattern which is clearly associated with this syndrome. There is no doubt that arachnoiditis occurs as a pathological and radiological entity due to a number of causes. In the view of the present authors, the nexus between the pathology and radiology on the one hand, and the patients' symptoms on the other hand, has not been demonstrated with any degree of scientific rigor.

  15. [Severe Raynaud's syndrome treated by lumbar sympathectomy].

    PubMed

    Thomsen, Thomas Laden; Roeder, Ole

    2016-03-28

    Avoiding exposure of extremities to cold combined with pharmacologic treatment usually suffice in the attempt to suppress the related symptoms of Raynaud's syndrome. This case report describes a severe case of Raynaud's syndrome affecting the lower extremities of a 16-year-old female. She was referred to a centre of vascular surgery with severe vasospasms of the feet. After failed attempts of pharmacologic treatment, a laparoscopic lumbar sympathectomy was performed with no complications and a slight reduction of symptoms three years post-surgically.

  16. Aneurysmal bone cyst of the lumbar spine.

    PubMed

    Cugati, Goutham; Pande, Anil; Jain, Pradeep K; Symss, Nigel Peter; Ramamurthi, Ravi; Vasudevan, Chakravarthy M

    2015-01-01

    An aneurysmal bone cyst (ABC) is a benign, locally proliferative vascular disorder of non-neoplastic osseous lesions in children and young adults. Seventy-five percent of ABCs occur before the age of 20 years. They comprise 1.4% of all primary bone tumors, and commonly occur in the long bones. Spinal ABCs are much rarer. We present to you one such rare case of ABC involving the lumbar spine which was successfully treated with surgery. The clinical pathological and radiological features are described. The treatment options available are discussed.

  17. Propellers in Saturn's rings

    NASA Astrophysics Data System (ADS)

    Sremcevic, M.; Stewart, G. R.; Albers, N.; Esposito, L. W.

    2014-04-01

    Theoretical studies and simulations have demonstrated the effects caused by objects embedded in planetary rings [5, 8]. Even if the objects are too small to be directly observed, each creates a much larger gravitational imprint on the surrounding ring material. These strongly depend on the mass of the object and range from "S" like propeller-shaped structures for about 100m-sized icy bodies to the opening of circumferential gaps as in the case of the embedded moons Pan and Daphnis and their corresponding Encke and Keeler Gaps. Since the beginning of the Cassini mission many of these smaller objects (~ 100m in size) have been identified in Saturn's A ring through their propeller signature in the images [10, 7, 9, 11]. Furthermore, recent Cassini observations indicate the possible existence of objects embedded even in Saturn's B and C ring [6, 2]. In this paper we present our new results about by now classical A ring propellers and more enigmatic B ring population. Due to the presence of self-gravity wakes the analysis of propeller brightness in ISS images always bears some ambiguity [7, 9] and consequently the exact morphology of propellers is not a settled issue. In 2008 we obtained a fortunate Cassini Ultraviolet Imaging Spectrograph (UVIS) occultation of the largest A ring propeller Bleriot. Utilizing Cassini ISS images we obtain Bleriot orbit and demonstrate that UVIS Persei Rev42 occultation did cut across Bleriot about 100km downstream from the center. The occultation itself shows a prominent partial gap and higher density outer flanking wakes, while their orientation is consistent with a downstream cut. While in the UVIS occultation the partial gap is more prominent than the flanking wakes, the features mostly seen in Bleriot images are actually flanking wakes. One of the most interesting aspects of the A ring propellers are their wanderings, or longitudinal deviations from a pure circular orbit [11]. We numerically investigated the possibility of simple moon

  18. Chemoembolization for Hepatocellular Carcinoma Supplied by a Lumbar Artery

    SciTech Connect

    Kim, Han Myun; Kim, Hyo-Cheol Woo, Sungmin; Son, Kyu Ri; Cho, Seong Whi; Chung, Jin Wook

    2015-02-15

    PurposeTo describe the radiologic findings and imaging response of hepatocellular carcinoma (HCC) supplied by the lumbar artery.MethodsBetween April 2004 and December 2012, we encountered HCC supplied by a lumbar artery in 21 patients. Two investigators retrospectively reviewed clinical and radiological findings of HCC supplied by the lumbar artery using computed tomography (CT) scans and digital subtraction angiograms.ResultsPatients had received 1–27 sessions of previous chemoembolization procedures (mean 7.7 sessions, median 4 sessions). Mean tumor size was 5.3 cm. The locations of HCC supplied by lumbar artery were the bare area (n = 14, 67 %) and segment VI (n = 7, 33 %). Tumor-feeding arteries arose from the main lumbar artery (n = 7), proximal anterior division (n = 4), and distal anterior division (n = 14). In 20 patients, selective chemoembolization through the tumor-feeding arteries of the lumbar artery was achieved. In 1 patient, nonselective embolization at the main lumbar artery was performed. There was no complication such as skin necrosis or paralysis. On the first follow-up enhanced CT scan, target tumors fed by the lumbar artery showed complete response (n = 6), partial response (n = 4), stable disease (n = 3), and progressive disease (n = 8), but overall tumor response was partial response (n = 1) and progressive disease (n = 20).ConclusionWhen HCC is located in the inferior tip or bare area of the liver, a lumbar artery may supply the tumor. Although selective chemoembolization via the tumor-feeding vessel of the lumbar artery can be achieved in most cases, overall tumor response is commonly unfavorable.

  19. Ring correlations in random networks

    NASA Astrophysics Data System (ADS)

    Sadjadi, Mahdi; Thorpe, M. F.

    2016-12-01

    We examine the correlations between rings in random network glasses in two dimensions as a function of their separation. Initially, we use the topological separation (measured by the number of intervening rings), but this leads to pseudo-long-range correlations due to a lack of topological charge neutrality in the shells surrounding a central ring. This effect is associated with the noncircular nature of the shells. It is, therefore, necessary to use the geometrical distance between ring centers. Hence we find a generalization of the Aboav-Weaire law out to larger distances, with the correlations between rings decaying away when two rings are more than about three rings apart.

  20. DC-Powered Jumping Ring

    NASA Astrophysics Data System (ADS)

    Jeffery, Rondo N.; Amiri, Farhang

    2016-02-01

    The classroom jumping ring demonstration is nearly always performed using alternating current (AC), in which the ring jumps or flies off the extended iron core when the switch is closed. The ring jumps higher when cooled with liquid nitrogen (LN2). We have performed experiments using DC to power the solenoid and find similarities and significant differences from the AC case. In particular, the ring does not fly off the core but rises a short distance and then falls back. If the ring jumps high enough, the rising and the falling motion of the ring does not follow simple vertical motion of a projectile. This indicates that there are additional forces on the ring in each part of its motion. Four possible stages of the motion of the ring with DC are identified, which result from the ring current changing directions during the jump in response to a changing magnetic flux through the moving ring.

  1. [Mechanical studies of lumbar interbody fusion implants].

    PubMed

    Bader, R J; Steinhauser, E; Rechl, H; Mittelmeier, W; Bertagnoli, R; Gradinger, R

    2002-05-01

    In addition to autogenous or allogeneic bone grafts, fusion cages composed of metal or plastic are being used increasingly as spacers for interbody fusion of spinal segments. The goal of this study was the mechanical testing of carbon fiber reinforced plastic (CFRP) fusion cages used for anterior lumbar interbody fusion. With a special testing device according to American Society for Testing and Materials (ASTM) standards, the mechanical properties of the implants were determined under four different loading conditions. The implants (UNION cages, Medtronic Sofamor Danek) provide sufficient axial compression, shear, and torsional strength of the implant body. Ultimate axial compression load of the fins is less than the physiological compression loads at the lumbar spine. Therefore by means of an appropriate surgical technique parallel grooves have to be reamed into the endplates of the vertebral bodies according to the fin geometry. Thereby axial compression forces affect the implants body and the fins are protected from damaging loading. Using a supplementary anterior or posterior instrumentation, in vivo failure of the fins as a result of physiological shear and torsional spinal loads is unlikely. Due to specific complications related to autogenous or allogeneic bone grafts, fusion cages made of metal or carbon fiber reinforced plastic are an important alternative implant in interbody fusion.

  2. Operative Management of Lumbar Degenerative Disc Disease

    PubMed Central

    Lee, Yu Chao; Osti, Orso Lorenzo

    2016-01-01

    Lumbar degenerative disc disease is extremely common. Current evidence supports surgery in carefully selected patients who have failed non-operative treatment and do not exhibit any substantial psychosocial overlay. Fusion surgery employing the correct grafting and stabilization techniques has long-term results demonstrating successful clinical outcomes. However, the best approach for fusion remains debatable. There is some evidence supporting the more complex, technically demanding and higher risk interbody fusion techniques for the younger, active patients or patients with a higher risk of non-union. Lumbar disc arthroplasty and hybrid techniques are still relatively novel procedures despite promising short-term and mid-term outcomes. Long-term studies demonstrating superiority over fusion are required before these techniques may be recommended to replace fusion as the gold standard. Novel stem cell approaches combined with tissue engineering therapies continue to be developed in expectation of improving clinical outcomes. Results with appropriate follow-up are not yet available to indicate if such techniques are safe, cost-effective and reliable in the long-term. PMID:27559465

  3. Management of symptomatic lumbar degenerative disk disease.

    PubMed

    Madigan, Luke; Vaccaro, Alexander R; Spector, Leo R; Milam, R Alden

    2009-02-01

    Symptomatic lumbar degenerative disk disease, or discogenic back pain, is difficult to treat. Patients often report transverse low back pain that radiates into the sacroiliac joints. Radicular or claudicatory symptoms are generally absent unless there is concomitant nerve compression. Physical examination findings are often unremarkable. Radiographic examination may reveal disk space narrowing, end-plate sclerosis, or vacuum phenomenon in the disk; magnetic resonance imaging is useful for revealing hydration of the disk, annular bulging, or lumbar spine end-plate (Modic) changes in the adjacent vertebral bodies. The use of diskography as a confirmatory study remains controversial. Recent prospective, randomized trials and meta-analyses of the literature have helped expand what is known about degenerative disk disease. In most patients with low back pain, symptoms resolve without surgical intervention; physical therapy and nonsteroidal anti-inflammatory drugs are the cornerstones of nonsurgical treatment. Intradiskal electrothermal treatment has not been shown to be effective, and arthrodesis remains controversial for the treatment of discogenic back pain. Nucleus replacement and motion-sparing technology are too new to have demonstrated long-term data regarding their efficacy.

  4. Propellers in Saturn's rings

    NASA Astrophysics Data System (ADS)

    Sremcevic, M.; Stewart, G. R.; Albers, N.; Esposito, L. W.

    2013-12-01

    Theoretical studies and simulations have demonstrated the effects caused by objects embedded in planetary rings. Even if the objects are too small to be directly observed, each creates a much larger gravitational imprint on the surrounding ring material. These strongly depend on the mass of the object and range from "S" like propeller-shaped structures for about 100m-sized icy bodies to the opening of circumferential gaps as in the case of the embedded moons Pan and Daphnis and their corresponding Encke and Keeler Gaps. Since the beginning of the Cassini mission many of these smaller objects (~<500m in size) have been indirectly identified in Saturn's A ring through their propeller signature in the images. Furthermore, recent Cassini observations indicate the possible existence of objects embedded even in Saturn's B and C ring. In this paper we present evidence for the existence of propellers in Saturn's B ring by combining data from Cassini Ultraviolet Imaging Spectrograph (UVIS) and Imaging Science Subsystem (ISS) experiments. We show evidence that B ring seems to harbor two distinct populations of propellers: "big" propellers covering tens of degrees in azimuth situated in the densest part of B ring, and "small" propellers in less dense inner B ring that are similar in size and shape to known A ring propellers. The population of "big" propellers is exemplified with a single object which is observed for 5 years of Cassini data. The object is seen as a very elongated bright stripe (40 degrees wide) in unlit Cassini images, and dark stripe in lit geometries. In total we report observing the feature in images at 18 different epochs between 2005 and 2010. In UVIS occultations we observe this feature as an optical depth depletion in 14 out of 93 occultation cuts at corrotating longitudes compatible with imaging data. Combining the available Cassini data we infer that the object is a partial gap located at r=112,921km embedded in the high optical depth region of the B

  5. Piston Ring Pressure Distribution

    NASA Technical Reports Server (NTRS)

    Kuhn, M.

    1943-01-01

    The discovery and introduction of the internal combustion engine has resulted in a very rapid development in machines utilizing the action of a piston. Design has been limited by the internal components of the engine, which has been subjected to ever increasing thermal and mechanical stresses, Of these internal engine components, the piston and piston rings are of particular importance and the momentary position of engine development is not seldom dependent upon the development of both of the components, The piston ring is a well-known component and has been used in its present shape in the steam engine of the last century, Corresponding to its importance, the piston ring has been a rich field for creative activity and it is noteworthy that in spite of this the ring has maintained its shape through the many years. From the many and complicated designs which have been suggested as a packing between piston and cylinder wall hardly one suggestion has remained which does not resemble the original design of cast iron rectangular ring.

  6. Stacked Corrugated Horn Rings

    NASA Technical Reports Server (NTRS)

    Sosnowski, John B.

    2010-01-01

    This Brief describes a method of machining and assembly when the depth of corrugations far exceeds the width and conventional machining is not practical. The horn is divided into easily machined, individual rings with shoulders to control the depth. In this specific instance, each of the corrugations is identical in profile, and only differs in diameter and outer profile. The horn is segmented into rings that are cut with an interference fit (zero clearance with all machining errors biased toward contact). The interference faces can be cut with a reverse taper to increase the holding strength of the joint. The taper is a compromise between the interference fit and the clearance of the two faces during assembly. Each internal ring is dipped in liquid nitrogen, then nested in the previous, larger ring. The ring is rotated in the nest until the temperature of the two parts equalizes and the pieces lock together. The resulting assay is stable, strong, and has an internal finish that cannot be achieved through other methods.

  7. A Biomechanical Stability Study of Extraforaminal Lumbar Interbody Fusion on the Cadaveric Lumbar Spine Specimens

    PubMed Central

    Guo, Song; Yan, Meijun; Han, Yingchao; Xia, Dongdong; Sun, Guixin; Li, Lijun; Tan, Jun

    2016-01-01

    Background Transforaminal lumbar interbody fusion (TLIF) is an effective surgery for lumbar degenerative disease. However, this fusion technique requires resection of inferior facet joint to provide access for superior facet joint resection, which results in reduced lumbar spinal stability and unnecessary trauma. We have previously developed extraforaminal lumbar interbody fusion (ELIF) that can avoid back muscle injury with direct nerve root decompression. This study aims to show that ELIF enhances lumbar spinal stability in comparison to TLIF by comparing lumbar spinal stability of L4–L5 range of motion (ROM) on 12 cadaveric spine specimens after performing TLIF or ELIF. Methods 12 cadaveric spine specimens were randomly divided and treated in accordance with the different internal fixations, including ELIF with a unilateral pedicle screw (ELIF+UPS), TLIF with a unilateral pedicle screw (TLIF+UPS), TLIF with a bilateral pedicle screw (TLIF+BPS), ELIF with a unilateral pedicle screw and translaminar facet screw (ELIF+UPS+TLFS) and ELIF with a bilateral pedicle screw (ELIF+BPS). The treatment groups were exposed to a 400-N load and 6 N·m movement force to calculate the angular displacement of L4-L5 during anterior flexion, posterior extension, lateral flexion and rotation operation conditions. Results The ROM in ELIF+UPS group was smaller than that of TLIF+UPS group under all operating conditions, with the significant differences in left lateral flexion and right rotation by 36.15% and 25.97% respectively. The ROM in ELIF+UPS group was higher than that in TLIF+BPS group. The ROM in the ELIF+UPS+TLFS group was much smaller than that in the ELIF+UPS group, but was not significantly different than that in the TLIF+BPS group. Conclusions Despite that TLIF+BPS has great stability, which can be comparable by that of ELIF+UPS. Additionally, ELIF stability can be further improved by using translaminar facet screws without causing more tissue damage to patient. PMID

  8. Rings in the solar system

    SciTech Connect

    Pollack, J.B.; Cuzzi, J.N.

    1981-11-01

    Saturn, Jupiter, and Uranus have rings with different structure and composition. The rings consist of tiny masses in independent orbits. Photographs and data obtained by the Voyager project have aided in the understanding of Saturn's rings. Spokes have been found in B ring and boards, knots, and twist in F ring. Particles on the order of a micrometer in size are believed to occur in F, B, and A rings. The dominant component is water ice. The rings of Uranus are narrow and separated by broad empty regions. The technique used to study them has been stellar occulation. Nothing is known of particle size. The dominant component is believed to be silicates rich in compounds that absorb sunlight. Jupiter's rings consist of 3 main parts: a bright ring, a diffuse disk, and a halo. Use of Pioneer 10 data and other techniques have indicated particle sizes on the order of several micrometers and some at least a centimeter in diameter. The architecture of the ring system results from the interplay of a number of forces. These include gravitational forces due to moons outside the rings and moonlets embedded in them, electromagnetic forces due to the planet's rotating magnetic field, and even the gentle forces exerted by the dilute gaseous medium in which the rings rotate. Each of these forces is discussed. Several alternative explanations of how the rings arose are considered. The primary difference in these hypotheses is the account of the relationship between the ring particles of today and the primordial ring material. (SC)

  9. Physics of planetary rings

    NASA Astrophysics Data System (ADS)

    Gorkavyi, N.

    2007-08-01

    It is difficult to enumerate all the surprises presented by the planetary rings. The Saturnian rings are stratified into thousands of ringlets and the Uranian rings are compressed into narrow streams, which for some reason or other differ from circular orbits like the wheel of an old bicycle. The edge of the rings is jagged and the rings themselves are pegged down under the gravitational pressure of the satellites, bending like a ship's wake. There are spiral waves, elliptical rings, strange interlacing of narrow ringlets, and to cap it all one has observed in the Neptunian ring system three dense, bright arcs - like bunches of sausages on a transparent string. For celestial mechanics this is a spectacle as unnatural as a bear's tooth in the necklace of the English queen. In the dynamics of planetary rings the physics of collective interaction was supplemented by taking collisions between particles into account. One was led to study a kinetic equation with a rather complex collision integral - because the collisions are inelastic - which later on made it possible, both by using the Chapman-Enskog method and by using the solution of the kinetic equation for a plasma in a magnetic field, to reduce it to a closed set of (hydrodynamical) moment equations [1]. The hydrodynamical instabilities lead to the growth of short-wavelength waves and large-scale structures of the Saturnian rings [1]. We have shown that the formation of the existing dense Uranian rings is connected with the capture of positively drifting ring particles in inner Lindblad resonances which arrest this drift [1]. After the formation of dense rings at the positions of satellite resonances the collective interaction between resonant particles is amplified and the rings can leave the resonance and drift away from the planet and the parent resonance. We can expect in the C ring an appreciable positive ballistic particle drift caused by the erosion of the B ring by micrometeorites. It is therefore natural

  10. Instrumented Posterior Lumbar Interbody Fusion in Adult Spondylolisthesis

    PubMed Central

    Yu, Ching-Hsiao; Wang, Chen-Ti

    2008-01-01

    It is unclear whether using artificial cages increases fusion rates compared with use of bone chips alone in posterior lumbar interbody fusion for patients with lumbar spondylolisthesis. We hypothesized artificial cages for posterior lumbar interbody fusion would provide better clinical and radiographic outcomes than bone chips alone. We assumed solid fusion would provide good clinical outcomes. We clinically and radiographically followed 34 patients with spondylolisthesis having posterior lumbar interbody fusion with mixed autogenous and allogeneic bone chips alone and 42 patients having posterior lumbar interbody fusion with implantation of artificial cages packed with morselized bone graft. Patients with the artificial cage had better functional improvement in the Oswestry disability index than those with bone chips alone, whereas pain score, patient satisfaction, and fusion rate were similar in the two groups. Postoperative disc height ratio, slip ratio, and segmental lordosis all decreased at final followup in the patients with bone chips alone but remained unchanged in the artificial cage group. The functional outcome correlated with radiographic fusion status. We conclude artificial cages provide better functional outcomes and radiographic improvement than bone chips alone in posterior lumbar interbody fusion for lumbar spondylolisthesis, although both techniques achieved comparable fusion rates. Level of Evidence: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18846411

  11. Postoperative seizure following transforaminal percutaneous endoscopic lumbar discectomy

    PubMed Central

    Kertmen, Hayri; Gürer, Bora; Yilmaz, Erdal Resit; Sekerci, Zeki

    2016-01-01

    Endoscopic surgery for lumbar disc herniation has been available for more than 30 years. Transforaminal percutaneous endoscopic lumbar discectomy is a well-known, safe, and effective method used for the treatment of the lumbar disc herniation. The published complications of the transforaminal percutaneous endoscopic lumbar discectomy consist of infections, thrombophlebitis, dysesthesia, dural tear, vascular injury, and death. Seizure after transforaminal percutaneous endoscopic lumbar discectomy is an extremely rare complication. A 20-year-old patient applied at our department who had undergone transforaminal percutaneous endoscopic lumbar. During the procedure, while performing the discography, non-ionic contrast media was administered into the thecal sac inadvertently. Two hours after surgery, the patient developed generalized tonic-clonic seizure of 5-min duration. Diagnosis of iohexol-induced seizure was made and the patient was treated supportively without anti-epileptics. Here we present the first case of seizure after transforaminal percutaneous endoscopic lumbar discectomy, which was caused by inadvertent administration of the contrast media into the thecal sac. PMID:27695562

  12. Deployable Fresnel Rings

    NASA Technical Reports Server (NTRS)

    Kennedy, Timothy F.; Fink, Patrick W.; Chu, Andrew W.; Lin, Gregory Y.

    2014-01-01

    Deployable Fresnel rings (DFRs) significantly enhance the realizable gain of an antenna. This innovation is intended to be used in combination with another antenna element, as the DFR itself acts as a focusing or microwave lens element for a primary antenna. This method is completely passive, and is also completely wireless in that it requires neither a cable, nor a connector from the antenna port of the primary antenna to the DFR. The technology improves upon the previous NASA technology called a Tri-Sector Deployable Array Antenna in at least three critical aspects. In contrast to the previous technology, this innovation requires no connector, cable, or other physical interface to the primary communication radio or sensor device. The achievable improvement in terms of antenna gain is significantly higher than has been achieved with the previous technology. Also, where previous embodiments of the Tri-Sector antenna have been constructed with combinations of conventional (e.g., printed circuit board) and conductive fabric materials, this innovation is realized using only conductive and non-conductive fabric (i.e., "e-textile") materials, with the possible exception of a spring-like deployment ring. Conceptually, a DFR operates by canceling the out-of-phase radiation at a plane by insertion of a conducting ring or rings of a specific size and distance from the source antenna, defined by Fresnel zones. Design of DFRs follow similar procedures to those outlined for conventional Fresnel zone rings. Gain enhancement using a single ring is verified experimentally and through computational simulation. The experimental test setup involves a microstrip patch antenna that is directly behind a single-ring DFR and is radiating towards a second microstrip patch antenna. The first patch antenna and DFR are shown. At 2.42 GHz, the DFR improves the transmit antenna gain by 8.6 dB, as shown in Figure 2, relative to the wireless link without the DFR. A figure illustrates the

  13. Rings dominate western Gulf

    NASA Astrophysics Data System (ADS)

    Vidal L., Francisco V.; Vidal L., Victor M. V.; Molero, José María Pérez

    Surface and deep circulation of the central and western Gulf of Mexico is controlled by interactions of rings of water pinched from the gulf's Loop Current. The discovery was made by Mexican oceanographers who are preparing a full-color, 8-volume oceanographic atlas of the gulf.Anticyclonic warm-core rings pinch off the Loop Current at a rate of about one to two per year, the scientists of the Grupo de Estudios Oceanográficos of the Instituto de Investigaciones Eléctricas (GEO-IIE) found. The rings migrate west until they collide with the continental shelf break of the western gulf, almost always between 22° and 23°N latitude. On their westward travel they transfer angular momentum and vorticity to the surrounding water, generating cyclonic circulations and vortex pairs that completely dominate the entire surface and deep circulation of the central and western gulf.

  14. Ring laser gyroscope anode

    SciTech Connect

    Ljung, B.H.

    1981-03-17

    An anode for a ring laser gyroscope which provides improved current stability in the glow discharge path is disclosed. The anode of this invention permits operation at lower currents thereby allowing a reduction of heat dissipation in the ring laser gyroscope. The anode of one embodiment of this invention is characterized by a thumbtack appearance with a spherical end where the normal sharp end of the thumbtack would be located. The stem of the anode extends from the outside of the gyroscope structure to the interior of the structure such that the spherical end is substantially adjacent to the laser beam.

  15. GUARD RING SEMICONDUCTOR JUNCTION

    DOEpatents

    Goulding, F.S.; Hansen, W.L.

    1963-12-01

    A semiconductor diode having a very low noise characteristic when used under reverse bias is described. Surface leakage currents, which in conventional diodes greatly contribute to noise, are prevented from mixing with the desired signal currents. A p-n junction is formed with a thin layer of heavily doped semiconductor material disposed on a lightly doped, physically thick base material. An annular groove cuts through the thin layer and into the base for a short distance, dividing the thin layer into a peripheral guard ring that encircles the central region. Noise signal currents are shunted through the guard ring, leaving the central region free from such currents. (AEC)

  16. Unidirectional ring lasers

    DOEpatents

    Hohimer, J.P.; Craft, D.C.

    1994-09-20

    Unidirectional ring lasers formed by integrating nonreciprocal optical elements into the resonant ring cavity is disclosed. These optical elements either attenuate light traveling in a nonpreferred direction or amplify light traveling in a preferred direction. In one preferred embodiment the resonant cavity takes the form of a circle with an S-shaped crossover waveguide connected to two points on the interior of the cavity such that light traveling in a nonpreferred direction is diverted from the cavity into the crossover waveguide and reinjected out of the other end of the crossover waveguide into the cavity as light traveling in the preferred direction. 21 figs.

  17. Unidirectional ring lasers

    DOEpatents

    Hohimer, John P.; Craft, David C.

    1994-01-01

    Unidirectional ring lasers formed by integrating nonreciprocal optical elements into the resonant ring cavity. These optical elements either attenuate light traveling in a nonpreferred direction or amplify light traveling in a preferred direction. In one preferred embodiment the resonant cavity takes the form of a circle with an S-shaped crossover waveguide connected to two points on the interior of the cavity such that light traveling in a nonpreferred direction is diverted from the cavity into the crossover waveguide and reinjected out of the other end of the crossover waveguide into the cavity as light traveling in the preferred direction.

  18. Ligaments associated with lumbar intervertebral foramina. 2. The fifth lumbar level.

    PubMed Central

    Amonoo-Kuofi, H S; el-Badawi, M G; Fatani, J A; Butt, M M

    1988-01-01

    The lumbosacral spines of two fetal and twelve adult cadavers have been studied by dissection. Evidence shows that the fifth lumbar intervertebral foramen is crossed on its external aspect by a strong, cord-like corporotransverse ligament passing obliquely downwards, forwards and medially from the inferior aspect of the accessory process of the fifth lumbar vertebra to the lateral surface of the intervertebral disc and the adjacent parts of the bodies of the fifth and first sacral vertebrae. Superficially, the ligament is related to another flat band--the lumbosacral hood. Together these ligaments separate and provide openings for the sympathetic ramus, the ventral ramus and blood vessels related to the intervertebral foramen. On the dorsal aspect, a tripartite ligament, the mamillo-transverso-accessory ligament, bears important relationships to the subdivisions of the dorsal ramus and also the zygapophyseal joint. The significance of these findings is discussed. Images Fig. 2 Fig. 3 Fig. 4 Fig. 1 Fig. 5 PMID:3248957

  19. Saturn's Rings, the Yarkovsky Effects, and the Ring of Fire

    NASA Technical Reports Server (NTRS)

    Rubincam, David Parry

    2004-01-01

    The dimensions of Saturn's A and B rings may be determined by the seasonal Yarkovsky effect and the Yarkovsky-Schach effect; the two effects confine the rings between approximately 1.68 and approximately 2.23 Saturn radii, in reasonable agreement with the observed values of 1.525 and 2.267. The C ring may be sparsely populated because its particles are transients on their way to Saturn; the infall may create a luminous Ring of Fire around Saturn's equator. The ring system may be young: in the past heat flow from Saturn's interior much above its present value would not permit rings to exist.

  20. Randomized clinical trial comparing lumbar percutaneous hydrodiscectomy with lumbar open microdiscectomy for the treatment of lumbar disc protrusions and herniations

    PubMed Central

    Cristante, Alexandre Fogaça; Rocha, Ivan Diasda; Marcon, Raphael Martus; de Barros Filho, Tarcísio Eloy Pessoa

    2016-01-01

    OBJECTIVES: Hydrodiscectomy is a new technique used for percutaneous spinal discectomy that employs a high-intensity stream of water for herniated disc ablation and tissue aspiration. No previous clinical study has examined the effects of percutaneous hydrodiscectomy. The aim of this study is to evaluate the outcomes of hydrodiscectomy compared to open microdiscectomy regarding pain, function, satisfaction, complications and recurrence rates. METHODS: In this randomized clinical trial, patients referred to our tertiary hospital for lumbar back pain were recruited and included in the study if they had disc protrusion or small herniation in only one level, without neurological deficits and with no resolution after six weeks of conservative treatment. One group underwent open microdiscectomy, and the other group underwent percutaneous microdiscectomy via hydrosurgery. Function was evaluated using the Oswestry Disability Index and pain was assessed using a visual analog scale. Evaluations were performed preoperatively, and then during the first week and at one, three, six and twelve months postoperatively. Personal satisfaction was verified. Clinicaltrials.gov: NCT01367860. RESULTS: During the study period, 20 patients were included in each arm and 39 completed one-year of follow-up (one patient died of unrelated causes). Both groups exhibited equal improvement on the visual analog scale and Oswestry evaluations after treatment, without any significant differences. The improvement in the lumbar visual analog scale score was not significant in the hydrodiscectomy group (p=0.138). The rates of infection, pain, recurrence and satisfaction were similar between the two groups. CONCLUSION: Percutaneous hydrodiscectomy was demonstrated to be as effective as open microdiscectomy for reducing pain. The rates of complications and recurrence of herniation were similar between groups. Patient satisfaction with the treatment was also similar between groups. PMID:27276397

  1. Influence Of Lumbar Spine Kinematics On Feet Pressure Distribution

    NASA Astrophysics Data System (ADS)

    Săftescu-Jescu, C.; Bereteu, L.

    2012-12-01

    Determining the center of pressure trajectories, as an indicator of postural stability or lumbar pathology, has been a challenging issue for researchers during the last decades. The paper advances an investigational method in order to determine a correlation between lumbar spine movements and feet center of pressure distribution. Five young healthy volunteers were simultaneously tested using an ultrasound based motion analyzing system and a force platform, while performing imposed tasks. Results showed specific patterns described by the center of pressure trajectories and a good coordination of angular amplitudes during lumbar spine movement.

  2. Contraindications to lumbar puncture as defined by computed cranial tomography.

    PubMed Central

    Gower, D J; Baker, A L; Bell, W O; Ball, M R

    1987-01-01

    Papilloedema is not always an adequate predictor of potential complications from lumbar puncture, and many clinicians are using computed tomography (CT) before lumbar puncture in an effort to identify more accurately the "at risk" patient. This paper identifies the following anatomical criteria defined by CT scanning that correlate with unequal pressures between intracranial compartments and predispose a patient to herniation following decompression of the spinal compartment: lateral shift of midline structures, loss of the suprachiasmatic and basilar cisterns, obliteration of the fourth ventricle, or obliteration of the superior cerebellar and quadrigeminal plate cisterns with sparing of the ambient cisterns. These criteria should be considered to be contraindications to lumbar puncture. Images PMID:3655817

  3. Benchmarking Lumbar Puncture Fluoroscopy Time during Fellowship Training.

    PubMed

    Yang, H; Schaffer, K; Liu, L; Mahesh, M; Yousem, D M

    2017-03-01

    We sought to establish a guide for identifying fellowship competency in performing fluoroscopically guided lumbar punctures. With a linear mixed-effects model, we compared the fluoroscopy time between the first and last 3 months of neuroradiology training. During 7 years, 55 fellows performed 1142 and 861 lumbar punctures in the first and last quarters of training. A target fluoroscopy time of 0.26 minutes, the upper 95% confidence interval, can serve as a fellowship benchmark for successfully achieving competence in fluoroscopically guided lumbar punctures.

  4. Comparison of the Dynesys Dynamic Stabilization System and Posterior Lumbar Interbody Fusion for Lumbar Degenerative Disease

    PubMed Central

    Zhang, Yang; Shan, Jian-Lin; Liu, Xiu-Mei; Li, Fang; Guan, Kai; Sun, Tian-Sheng

    2016-01-01

    Background There have been few studies comparing the clinical and radiographic outcomes between the Dynesys dynamic stabilization system and posterior lumbar interbody fusion (PLIF). The objective of this study is to compare the clinical and radiographic outcomes of Dynesys and PLIF for lumbar degenerative disease. Methods Of 96 patients with lumbar degenerative disease included in this retrospectively analysis, 46 were treated with the Dynesys system and 50 underwent PLIF from July 2008 to March 2011. Clinical and radiographic outcomes were evaluated. We also evaluated the occurrence of radiographic and symptomatic adjacent segment degeneration (ASD). Results The mean follow-up time in the Dynesys group was 53.6 ± 5.3 months, while that in the PLIF group was 55.2 ± 6.8 months. At the final follow-up, the Oswestry disability index and visual analogue scale score were significantly improved in both groups. The range of motion (ROM) of stabilized segments in Dynesys group decreased from 7.1 ± 2.2° to 4.9 ± 2.2° (P < 0.05), while that of in PLIF group decreased from 7.3 ± 2.3° to 0° (P < 0.05). The ROM of the upper segments increased significantly in both groups at the final follow-up, the ROM was higher in the PLIF group. There were significantly more radiographic ASDs in the PLIF group than in the Dynesys group. The incidence of complications was comparable between groups. Conclusions Both Dynesys and PLIF can improve the clinical outcomes for lumbar degenerative disease. Compared to PLIF, Dynesys stabilization partially preserves the ROM of the stabilized segments, limits hypermobility in the upper adjacent segment, and may prevent the occurrence of ASD. PMID:26824851

  5. Traumatic lumbar artery rupture after lumbar spinal fracture dislocation causing hypovolemic shock: An endovascular treatment.

    PubMed

    Eun, Jong-Pil; Oh, Young-Min

    2015-01-01

    Recently, we observed a case of lumbar artery injury after trauma, which was treated by endovascular embolization. A 67-year-old woman who was injured in a traffic accident was brought to the emergency room. She was conscious and her hemodynamic condition was stable, but she had paraplegia below L1 dermatome. Contrast-enhanced computed tomography scan of abdomen and pelvis revealed fracture dislocation of L3/4 along with retroperitoneal hematomas. However, there was no evidence of traumatic injury in both thoracic and abdominal cavity. At that time, her blood pressure suddenly decreased to 60/40 mmHg and her mental status deteriorated. Also, her hemoglobin level was 5.4 g/dl. While her hemodynamic condition stabilized with massive fluid resuscitation including blood transfusion, an angiography was immediately performed to look for and embolize site of retroperitoneal hemorrhage. On the angiographic images, there was an active extravasation from ruptured left 3rd lumbar artery, and we performed complete embolization with GELFOAM and coil. Lumbar artery injury after trauma is rare and endovascular treatment is useful in case of hemodynamic instability.

  6. Suprapedicular Foraminal Endoscopic Approach to Lumbar Lateral Recess Decompression Surgery to Treat Degenerative Lumbar Spinal Stenosis

    PubMed Central

    Wang, Ya-peng; Zhang, Wei; Li, Bao-li; Sun, Ya-peng; Ding, Wen-yuan; Shen, Yong

    2016-01-01

    Background To discuss the strategy of suprapedicular foraminal endoscopic approach to lumbar lateral recess decompression and evaluate the safety and effectiveness of this strategy. Material/Methods Complete clinical information of 52 cases of lumbar lateral recess decompression with therapy of suprapedicular foraminal endoscopic approach were analyzed during the period from February 2010 to April 2014 in the Third Hospital of Hebei. All patients were followed up for 24 months, and VAS, JOA, ODI, and LRD were compared between preoperative and postoperative therapy and changes of FA. Intraoperative and postoperative complications were recorded and the safety of the surgery was evaluated. The surgical “excellent” and “good” rates were evaluated using MacNab score. Results VAS scores for lumbago and leg pain at 3, 6, 12, and 24 months after surgery were significantly lower than before surgery (p<0.05). JOA scores at 12 and 24 months after surgery were significantly higher than before surgery (p<0.05). ODI at 12 and 24 months after surgery were significantly lower than before surgery (p<0.05). LRD after surgery was higher (p<0.05), and FA was lower than before surgery. Conclusions Use of the suprapedicular foraminal endoscopic approach to lumbar lateral recess decompression is safe and effective, and this minimally invasive treatment can achieve satisfactory results, especially for elderly patients with complicated underlying diseases. PMID:27890911

  7. The effects of gluteus muscle strengthening exercise and lumbar stabilization exercise on lumbar muscle strength and balance in chronic low back pain patients

    PubMed Central

    Jeong, Ui-Cheol; Sim, Jae-Heon; Kim, Cheol-Yong; Hwang-Bo, Gak; Nam, Chan-Woo

    2015-01-01

    [Purpose] The aim of this study was to examine the effects of exercise to strengthen the muscles of the hip together with lumbar segmental stabilization exercise on the lumbar disability index, lumbar muscle strength, and balance. [Subjects and Methods] This study randomly and equally assigned 40 participants who provided written consent to participate in this study to a lumbar segmental stabilization exercise plus exercise to strengthen the muscles of the gluteus group (SMG + LES group) and a lumbar segmental stabilization exercise group. [Results] Each evaluation item showed a statistically significant effect. [Conclusion] Clinical application of exercise in this study showed that lumbar segmental stabilization exercise plus exercise to strengthen the muscles of the gluteus resulted in a greater decrease in low back pain disability index and increase in lumbar muscle strength and balance ability than lumbar segmental stabilization exercise in chronic low back pain patients receiving the exercise treatments during the same period. PMID:26834359

  8. Ring Flame Stabilizer

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The Ring Flame Stabilizer has been developed in conjunction with Lewis Research Center. This device can lower pollutant emissions (which contribute to smog and air pollution) from natural-gas appliances such as furnaces and water heaters by 90 percent while improving energy efficiency by 2 percent.

  9. Ring of Stellar Death

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This false-color image from NASA's Spitzer Space Telescope shows a dying star (center) surrounded by a cloud of glowing gas and dust. Thanks to Spitzer's dust-piercing infrared eyes, the new image also highlights a never-before-seen feature -- a giant ring of material (red) slightly offset from the cloud's core. This clumpy ring consists of material that was expelled from the aging star.

    The star and its cloud halo constitute a 'planetary nebula' called NGC 246. When a star like our own Sun begins to run out of fuel, its core shrinks and heats up, boiling off the star's outer layers. Leftover material shoots outward, expanding in shells around the star. This ejected material is then bombarded with ultraviolet light from the central star's fiery surface, producing huge, glowing clouds -- planetary nebulas -- that look like giant jellyfish in space.

    In this image, the expelled gases appear green, and the ring of expelled material appears red. Astronomers believe the ring is likely made of hydrogen molecules that were ejected from the star in the form of atoms, then cooled to make hydrogen pairs. The new data will help explain how planetary nebulas take shape, and how they nourish future generations of stars.

    This image composite was taken on Dec. 6, 2003, by Spitzer's infrared array camera, and is composed of images obtained at four wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red).

  10. Exotic damping ring lattices

    SciTech Connect

    Palmer, R.B.

    1987-05-01

    This paper looks at, and compares three types of damping ring lattices: conventional, wiggler lattice with finite ..cap alpha.., wiggler lattice with ..cap alpha.. = 0, and observes the attainable equilibrium emittances for the three cases assuming a constraint on the attainable longitudinal impedance of 0.2 ohms. The emittance obtained are roughly in the ratio 4:2:1 for these cases.

  11. Ring laser scatterometer

    DOEpatents

    Ackermann, Mark; Diels, Jean-Claude

    2005-06-28

    A scatterometer utilizes the dead zone resulting from lockup caused by scatter from a sample located in the optical path of a ring laser at a location where counter-rotating pulses cross. The frequency of one pulse relative to the other is varied across the lockup dead zone.

  12. Reading, Writing, and Rings!

    ERIC Educational Resources Information Center

    Aschbacher, Pamela; Li, Erika; Hammon, Art

    2008-01-01

    "Reading, Writing, and Rings!" was created by a team of elementary teachers, literacy experts, and scientists in order to integrate science and literacy. These free units bring students inside NASA's Cassini-Huygens mission to Saturn. The authors--a science teacher and education outreach specialist and two evaluators of educational programs--have…

  13. Making Molecular Borromean Rings

    ERIC Educational Resources Information Center

    Pentecost, Cari D.; Tangchaivang, Nichol; Cantrill, Stuart J.; Chichak, Kelly S.; Peters, Andrea J.; Stoddart, Fraser J.

    2007-01-01

    A procedure that requires seven 4-hour blocks of time to allow undergraduate students to prepare the molecular Borromean rings (BRs) on a gram-scale in 90% yield is described. The experiment would serve as a nice capstone project to culminate any comprehensive organic laboratory course and expose students to fundamental concepts, symmetry point…

  14. Microscopic lysis of lumbar adhesive arachnoiditis.

    PubMed

    Johnston, J D; Matheny, J B

    1978-03-01

    The results of a long-term study of 28 patients operated on for adhesive lumbar arachnoiditis are presented. The technique involved was microscopic lysis of adhesions. The first case of surgery was performed in 1966 and the last, in 1970, with followup through 1976. Numerous observations are made regarding the clinical picture and the appearance of arachnoiditis at the time of surgery. Some conclusions are drawn regarding the causes of this condition with some emphasis on the role of Pantopaque, multiple surgeries, and other trauma. The conclusion is that surgical attack on arachnoiditis is a straightforward surgical exercise that, when carried out with appropriate caution, produces no further neurologic deficits and some short-term improvement. However, the authors feel that this procedure should not be performed at the present time because there does not appear to be a method for preventing the reaccumulation of the scar tissue and subsequent recurrence of the symptoms.

  15. Conservative treatments for lumbar radicular pain.

    PubMed

    Fleury, Gregory; Nissen, Michael J; Genevay, Stéphane

    2014-10-01

    Lumbar radicular pain is a frequent medical pathology and represents a significant burden on society. The diagnosis of sciatica is largely clinical, in the setting of a combination of radicular pain and neurologic deficits (motor, reflexes, and/or sensation) or a positive straight leg raise test. Imaging is generally not necessary for sciatica, except in the presence of warning signs or in the setting of persisting or worsening pain. The recommended first-line treatment has not yet been clearly established. The choice of a conservative treatment approach combined with simple analgesics in the initial stages seems to be reasonable. A detailed discussion with the patient is important to explain the fact that surgery may only be necessary in the event of pain persisting in excess of 3 months or because of the development or worsening of a neurologic deficit. More high quality studies are clearly required to assist the medical practitioner in knowing how best to treat this group of patients.

  16. Methodologic evaluation of the lumbar disc syndrome.

    PubMed Central

    Robinson, J. S.

    1981-01-01

    Though the lumbar disc syndrome is a costly and ubiquitous affliction, effective evaluation of the disease process has been confounded by major unaddressed methodological short falls. Prominent difficulties include: inattention to the clinical boundaries of the syndrome, neglected co-morbid disease processes, comparison of unequal treatment groups and premature clinical data extrapolation, inadequate diagnostic validation, variability in surgical observation, and reliance upon follow-up techniques faulted by unaddressed distorting factors. Proposals for improvement include: formulation of suitable stratification subgroups emphasizing age and sign-symptom intensity and duration, techniques for improved diagnostic return from surgical exploration, suggestions toward improved quantitation of clinical testing procedures, and implantation of a quality of life scale. PMID:6454306

  17. Roentgenographic measurement of lumbar intervertebral disc height.

    PubMed

    Andersson, G B; Schultz, A; Nathan, A; Irstam, L

    1981-01-01

    The influences of differences in both intervertebral motion segment orientations and in reader judgments on measurements of the apparent intervertebral disc heights in lateral roentgenographs of the lumbar spine were examined. Forty-nine roentgenographs were obtained of nine discs that were titled laterally up to +/- 10 degrees, and rotated longitudinally up to +/- 20 degrees. Three orthopaedic surgeons and three radiologists measured disc heights from five of these roentgenographs, all using the same measurement method. The differences in apparent height that resulted from the orientation changes and differences in judgments among the six readers were considerable, usually of the order of one half of the nominal disc height. The results show that, while roentgenographic measurements can be used to estimate disc height, accurate measurements cannot readily be made from routine roentgenographs, and the interpretation should always be cautious.

  18. Traumatic subdural hematoma in the lumbar spine.

    PubMed

    Song, Jenn-Yeu; Chen, Yu-Hao; Hung, Kuang-Chen; Chang, Ti-Sheng

    2011-10-01

    Traumatic spinal subdural hematoma is rare and its mechanism remains unclear. This intervention describes a patient with mental retardation who was suffering from back pain and progressive weakness of the lower limbs following a traffic accident. Magnetic resonance imaging of the spine revealed a lumbar subdural lesion. Hematoma was identified in the spinal subdural space during an operation. The muscle power of both lower limbs recovered to normal after surgery. The isolated traumatic spinal subdural hematoma was not associated with intracranial subdural hemorrhage. A spinal subdural hematoma should be considered in the differential diagnosis of spinal cord compression, especially for patients who have sustained spinal trauma. Emergency surgical decompression is usually the optimal treatment for a spinal subdural hematoma with acute deterioration and severe neurological deficits.

  19. Lumbar osteosarcoma in a chinchilla (Chinchilla laniger).

    PubMed

    Simova-Curd, S; Nitzl, D; Pospischil, A; Hatt, J-M

    2008-09-01

    An 11-year-old male chinchilla was presented for investigation of progressive weight loss, apathy, anorexia, changes in faecal quality and alopecia on the tip of the tail. On clinical examination, a stiffness of the back legs was noted. Abdominal palpation revealed a hard immobile, irregular structure in the region of the last lumbar vertebrae. Subsequent radiography and ultrasonography suggested the presence of neoplasia. The following day the chinchilla was showing hindlimb paralysis, and there was severe self-trauma to the distal 5 cm of the tail. In view of the rapid clinical deterioration, the chinchilla was euthanased with the owner's consent. Macroscopic examination supported the clinical suspicion of neoplasia. Histopathological examination revealed a reactive osteoblastic osteosarcoma. To the author's knowledge, this is the first report of osteosarcoma in chinchillas.

  20. Methods of evaluating lumbar and cervical fusion.

    PubMed

    Gruskay, Jordan A; Webb, Matthew L; Grauer, Jonathan N

    2014-03-01

    Introduced in 1911, spinal fusion is now widely used to stabilize the cervical, thoracic, and lumbar spine. Despite advancements in surgical techniques, including the use of instrumentation and optimizing bone graft options, pseudarthrosis remains one of the most significant causes of clinical failure following attempted fusion. Diagnosis of this common complication is based on a focused clinical assessment and imaging studies. Pseudarthrosis classically presents with the onset of or return of axial or radicular symptoms during the first postoperative year. However, this diagnosis is complicated because other diagnoses can mimic these symptoms (such as infection or adjacent segment degeneration) and because many cases of pseudarthrosis are asymptomatic. Computed tomography and assessment of motion on flexion/extension radiographs are the two preferred imaging modalities for establishing the diagnosis of pseudarthrosis. The purpose of this article was to review the current status of imaging and clinical practices for assessing fusion following spinal arthrodesis.

  1. Ring Bubbles of Dolphins

    NASA Technical Reports Server (NTRS)

    Shariff, Karim; Marten, Ken; Psarakos, Suchi; White, Don J.; Merriam, Marshal (Technical Monitor)

    1996-01-01

    The article discusses how dolphins create and play with three types of air-filled vortices. The underlying physics is discussed. Photographs and sketches illustrating the dolphin's actions and physics are presented. The dolphins engage in this behavior on their own initiative without food reward. These behaviors are done repeatedly and with singleminded effort. The first type is the ejection of bubbles which, after some practice on the part of the dolphin, turn into toroidal vortex ring bubbles by the mechanism of baroclinic torque. These bubbles grow in radius and become thinner as they rise vertically to the surface. One dolphin would blow two in succession and guide them to fuse into one. Physicists call this a vortex reconnection. In the second type, the dolphins first create an invisible vortex ring in the water by swimming on their side and waving their tail fin (also called flukes) vigorously. This vortex ring travels horizontally in the water. The dolphin then turns around, finds the vortex and injects a stream of air into it from its blowhole. The air "fills-out" the core of the vortex ring. Often, the dolphin would knock-off a smaller ring bubble from the larger ring (this also involves vortex reconnection) and steer the smaller ring around the tank. One other dolphin employed a few other techniques for planting air into the fluke vortex. One technique included standing vertically in the water with tail-up, head-down and tail piercing the free surface. As the fluke is waved to create the vortex ring, air is entrained from above the surface. Another technique was gulping air in the mouth, diving down, releasing air bubbles from the mouth and curling them into a ring when they rose to the level of the fluke. In the third type, demonstrated by only one dolphin, the longitudinal vortex created by the dorsal fin on the back is used to produce 10-15 foot long helical bubbles. In one technique she swims in a curved path. This creates a dorsal fin vortex since

  2. Rings from Close Encounters

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-09-01

    Weve recently discovered narrow sets of rings around two minor planets orbiting in our solar system. How did these rings form? A new study shows that they could be a result of close encounters between the minor planets and giants like Jupiter or Neptune.Unexpected Ring SystemsPositions of the centaurs in our solar system (green). Giant planets (red), Jupiter trojans (grey), scattered disk objects (tan) and Kuiper belt objects (blue) are also shown. [WilyD]Centaurs are minor planets in our solar system that orbit between Jupiter and Neptune. These bodies of which there are roughly 44,000 with diameters larger than 1 km have dynamically unstable orbits that cross paths with those of one or more giant planets.Recent occultation observations of two centaurs, 10199 Chariklo and 2060 Chiron, revealed that these bodies both host narrow ring systems. Besides our four giant planets, Chariklo and Chiron are the only other bodies in the solar system known to have rings. But how did these rings form?Scientists have proposed several models, implicating collisions, disruption of a primordial satellite, or dusty outgassing. But a team of scientists led by Ryuki Hyodo (Paris Institute of Earth Physics, Kobe University) has recently proposed an alternative scenario: what if the rings were formed from partial disruption of the centaur itself, after it crossed just a little too close to a giant planet?Tidal Forces from a GiantHyodo and collaborators first used past studies of centaur orbits to estimate that roughly 10% of centaurs experience close encounters (passing within a distance of ~2x the planetary radius) with a giant planet during their million-year lifetime. The team then performed a series of simulations of close encounters between a giant planet and a differentiated centaur a body in which the rocky material has sunk to form a dense silicate core, surrounded by an icy mantle.Some snapshots of simulation outcomes (click for a closer look!) for different initial states of

  3. Lumbar puncture in patients using anticoagulants and antiplatelet agents.

    PubMed

    Domingues, Renan; Bruniera, Gustavo; Brunale, Fernando; Mangueira, Cristóvão; Senne, Carlos

    2016-08-01

    The use of anticoagulants and antiplatelet agents has largely increased. Diagnostic lumbar puncture in patients taking these drugs represents a challenge considering the opposing risks of bleeding and thrombotic complications. To date there are no controlled trials, specific guidelines, nor clear recommendations in this area. In the present review we make some recommendations about lumbar puncture in patients using these drugs. Our recommendations take into consideration the pharmacology of these drugs, the thrombotic risk according to the underlying disease, and the urgency in cerebrospinal fluid analysis. Evaluating such information and a rigorous monitoring of neurological symptoms after lumbar puncture are crucial to minimize the risk of hemorrhage associated neurological deficits. An individualized patient decision-making and an effective communication between the assistant physician and the responsible for conducting the lumbar puncture are essential to minimize potential risks.

  4. Quantitative magnetic resonance imaging of the lumbar intervertebral discs.

    PubMed

    Hwang, Dosik; Kim, Sewon; Abeydeera, Nirusha A; Statum, Sheronda; Masuda, Koichi; Chung, Christine B; Siriwanarangsun, Palanan; Bae, Won C

    2016-12-01

    Human lumbar spine is composed of multiple tissue components that serve to provide structural stability and proper nutrition. Conventional magnetic resonance (MR) imaging techniques have been useful for evaluation of IVD, but inadequate at imaging the discovertebral junction and ligamentous tissues due primarily to their short T2 nature. Ultrashort time to echo (UTE) MR techniques acquire sufficient MR signal from these short T2 tissues, thereby allowing direct and quantitative evaluation. This article discusses the anatomy of the lumbar spine, MR techniques available for morphologic and quantitative MR evaluation of long and short T2 tissues of the lumbar spine, considerations for T2 relaxation modeling and fitting, and existing and new techniques for spine image post-processing, focusing on segmentation. This article will be of interest to radiologic and orthopaedic researchers performing lumbar spine imaging.

  5. Quantitative magnetic resonance imaging of the lumbar intervertebral discs

    PubMed Central

    Hwang, Dosik; Kim, Sewon; Abeydeera, Nirusha A.; Statum, Sheronda; Masuda, Koichi; Chung, Christine B.; Siriwanarangsun, Palanan

    2016-01-01

    Human lumbar spine is composed of multiple tissue components that serve to provide structural stability and proper nutrition. Conventional magnetic resonance (MR) imaging techniques have been useful for evaluation of IVD, but inadequate at imaging the discovertebral junction and ligamentous tissues due primarily to their short T2 nature. Ultrashort time to echo (UTE) MR techniques acquire sufficient MR signal from these short T2 tissues, thereby allowing direct and quantitative evaluation. This article discusses the anatomy of the lumbar spine, MR techniques available for morphologic and quantitative MR evaluation of long and short T2 tissues of the lumbar spine, considerations for T2 relaxation modeling and fitting, and existing and new techniques for spine image post-processing, focusing on segmentation. This article will be of interest to radiologic and orthopaedic researchers performing lumbar spine imaging. PMID:28090450

  6. Sacroiliac joint pain after lumbar/lumbosacral fusion: current knowledge.

    PubMed

    Yoshihara, Hiroyuki

    2012-09-01

    Recently, the sacroiliac joint (SIJ) has gained increased attention as a source of persistent or new pain after lumbar/lumbosacral fusion. The underlying pathophysiology of SIJ pain may be increased mechanical load, iliac crest bone grafting, or a misdiagnosis of SIJ syndrome. Imaging studies show more frequent degeneration of the SIJ in patients with lumbar/lumbosacral fusion than in patients without such fusion. Using injection tests, it has been shown that SIJ pain is the cause of persistent symptoms in a considerable number of patients after fusion surgery. Recent articles reporting on surgical outcomes of SIJ fusion include a high percentage of patients who had lumbar/lumbosacral fusion or surgery before, although well-controlled clinical studies are necessary to assess the efficacy of surgical treatment. Taking these findings into consideration, the possibility that the SIJ is the source of pain should be considered in patients with failed back surgery syndrome after lumbar/lumbosacral fusion.

  7. Concomitant Lumbar Stenosis and Aortic Pseudoaneurysm: A Case Report

    PubMed Central

    Fuchs, Christoph; Niemeier, Thomas E; Neway, William E

    2016-01-01

    Aortic pseudoaneurysm can create a constellation of symptoms that can mimic lumbar back pain. There are rare but well-documented reports of aortic pathology (aneurysms, pseudoaneurysms, and chronic contained aneurysm ruptures) eroding into the vertebral column causing neural compression. We report a case of a rapidly progressive aortic pseudoaneurysm in a patient with pre-existing lumbar spine pathology which had the potential for catastrophic intraoperative bleeding during a minimally invasive surgery (MIS) using the transforaminal lumbar interbody fusion (TLIF) technique. Postoperatively, the patient’s radicular pain resolved but her back pain remained. Further workup identified the pseudoaneurysm and the patient subsequently underwent open vascular repair. In this report, we highlight a lesser known mimicker of lumbar back pain. PMID:27882269

  8. 49 CFR 572.19 - Lumbar spine, abdomen and pelvis.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... rotation joints by the attachments shown in Figure 18. Tighten the mountings so that the pelvis-lumbar joining surface is horizontal and adjust the femur ball-flange screws at each hip socket joint to 50...

  9. 49 CFR 572.19 - Lumbar spine, abdomen and pelvis.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... rotation joints by the attachments shown in Figure 18. Tighten the mountings so that the pelvis-lumbar joining surface is horizontal and adjust the femur ball-flange screws at each hip socket joint to 50...

  10. 49 CFR 572.19 - Lumbar spine, abdomen and pelvis.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... rotation joints by the attachments shown in Figure 18. Tighten the mountings so that the pelvis-lumbar joining surface is horizontal and adjust the femur ball-flange screws at each hip socket joint to 50...

  11. 49 CFR 572.19 - Lumbar spine, abdomen and pelvis.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... rotation joints by the attachments shown in Figure 18. Tighten the mountings so that the pelvis-lumbar joining surface is horizontal and adjust the femur ball-flange screws at each hip socket joint to 50...

  12. 49 CFR 572.19 - Lumbar spine, abdomen and pelvis.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... rotation joints by the attachments shown in Figure 18. Tighten the mountings so that the pelvis-lumbar joining surface is horizontal and adjust the femur ball-flange screws at each hip socket joint to 50...

  13. Lumbar Scoliosis Combined Lumbar Spinal Stenosis and Herniation Diagnosed Patient Was Treated with “U” Route Transforaminal Percutaneous Endoscopic Lumbar Discectomy

    PubMed Central

    Zhang, Shaobo; Lian, Qingquan; Yan, Haibo; Lin, Xianfa

    2017-01-01

    The objective was to report a case of a 63-year-old man with a history of low back pain (LBP) and left leg pain for 2 years, and the symptom became more serious in the past 5 months. The patient was diagnosed with lumbar scoliosis combined with lumbar spinal stenosis (LSS) and lumbar disc herniation (LDH) at the level of L4-5 that was confirmed using Computerized Topography and Magnetic Resonance Imaging. The surgical team preformed a novel technique, “U” route transforaminal percutaneous endoscopic lumbar discectomy (PELD), which led to substantial, long-term success in reduction of pain intensity and disability. After removing the osteophyte mass posterior to the thecal sac at L4-5, the working channel direction was changed to the gap between posterior longitudinal ligament and thecal sac, and we also removed the herniation and osteophyte at L3-4 with “U” route PELD. The patient's symptoms were improved immediately after the surgical intervention; low back pain intensity decreased from preoperative 9 to postoperative 2 on a visual analog scale (VAS) recorded at 1 month postoperatively. The success of the intervention suggests that “U” route PELD may be a feasible alternative to treat lumbar scoliosis with LSS and LDH patients. PMID:28203471

  14. Clinical Outcomes of Posterior Lumbar Interbody Fusion versus Minimally Invasive Transforaminal Lumbar Interbody Fusion in Three-Level Degenerative Lumbar Spinal Stenosis

    PubMed Central

    Fan, Guoxin; Wu, Xinbo; Yu, Shunzhi; Sun, Qi; Zhang, Hailong; Gu, Xin

    2016-01-01

    The aim of this study was to directly compare the clinical outcomes of posterior lumbar interbody fusion (PLIF) and minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) in three-level lumbar spinal stenosis. This retrospective study involved a total of 60 patients with three-level degenerative lumbar spinal stenosis who underwent MIS-TLIF or PLIF from January 2010 to February 2012. Back and leg visual analog scale (VAS), Oswestry Disability Index (ODI), and Short Form-36 (SF-36) scale were used to assess the pain, disability, and health status before surgery and postoperatively. In addition, the operating time, estimated blood loss, and hospital stay were also recorded. There were no significant differences in back VAS, leg VAS, ODI, SF-36, fusion condition, and complications at 12-month follow-up between the two groups (P > 0.05). However, significantly less blood loss and shorter hospital stay were observed in MIS-TLIF group (P < 0.05). Moreover, patients undergoing MIS-TLIF had significantly lower back VAS than those in PLIF group at 6-month follow-up (P < 0.05). Compared with PLIF, MIS-TLIF might be a prior option because of noninferior efficacy as well as merits of less blood loss and quicker recovery in treating three-level lumbar spinal stenosis. PMID:27747244

  15. Lumbar intervertebral disc degeneration and related factors in Korean firefighters

    PubMed Central

    Jang, Tae-Won; Ahn, Yeon-Soon; Byun, Junsu; Lee, Jong-In; Kim, Kun-Hyung; Kim, Youngki; Song, Han-Soo; Lee, Chul-Gab; Kwon, Young-Jun; Yoon, Jin-Ha; Jeong, Kyoungsook

    2016-01-01

    Objectives The job of firefighting can cause lumbar burden and low back pain. This study aimed to identify the association between age and lumbar intervertebral disc degeneration and whether the association differs between field and administrative (non-field) firefighters. Methods Subjects were selected using a stratified random sampling method. Firefighters were stratified by geographic area, gender, age and type of job. First, 25 fire stations were randomly sampled considering regional distribution. Then firefighters were stratified by gender, age and their job and randomly selected among the strata. A questionnaire survey and MRI scans were performed, and then four radiologists used Pfirrmann classification methods to determine the grade of lumbar intervertebral disc degeneration. Results Pfirrmann grade increased with lumbar intervertebral disc level. Analysis of covariance showed that age was significantly associated with lumbar intervertebral disc degeneration (p<0.05). The value of β (parameter estimate) was positive at all lumbar intervertebral disc levels and was higher in the field group than in the administrative group at each level. In logistic regression analysis, type of job was statistically significant only with regard to the L4–5 intervertebral disc (OR 3.498, 95% CI 1.241 to 9.860). Conclusions Lumbar intervertebral disc degeneration is associated with age, and field work such as firefighting, emergency and rescue may accelerate degeneration in the L4–5 intervertebral disc. The effects of field work on lumbar intervertebral disc degeneration were not clear in discs other than at the level L4–5. PMID:27354080

  16. Lumbar Spine Musculoskeletal Physiology and Biomechanics During Simulated Military Operations

    DTIC Science & Technology

    2015-06-01

    AWARD NUMBER: W81XWH-13-2-0043 TITLE: Lumbar Spine Musculoskeletal Physiology and Biomechanics During Simulated Military Operations PRINCIPAL...muscle physiology and lumbar spine kinematics data we have collected to date. We currently have three manuscripts in preparation for this study...Evaluation of SEAL Delivery Vehicles Unit Level Training The primary aim of this project is to describe the physiological , physical, cognitive and sleep

  17. Degenerative lumbar spinal stenosis and its imposters: three case studies

    PubMed Central

    Ammendolia, Carlo

    2014-01-01

    Degenerative lumbar spinal stenosis causing neurogenic claudicaton is a common condition impacting walking ability in older adults. There are other highly prevalent conditions in this patient population that have similar signs and symptoms and cause limited walking ability. The purpose of this study is to highlight the diagnostic challenges using three case studies of older adults who present with limited walking ability who have imaging evidence of degenerative lumbar spinal stenosis. PMID:25202160

  18. Inorganic glass ceramic slip rings

    NASA Technical Reports Server (NTRS)

    Glossbrenner, E. W.; Cole, S. R.

    1972-01-01

    Prototypes of slip rings have been fabricated from ceramic glass, a material which is highly resistant to deterioration due to high temperature. Slip ring assemblies were not structurally damaged by mechanical tests and performed statisfactorily for 200 hours.

  19. Midline Lumbar Fusion with Cortical Bone Trajectory Screw

    PubMed Central

    MIZUNO, Masaki; KURAISHI, Keita; UMEDA, Yasuyuki; SANO, Takanori; TSUJI, Masanori; SUZUKI, Hidenori

    2014-01-01

    A novel cortical bone trajectory (CBT) screw technique provides an alternative fixation technique for lumbar spine. Trajectory of CBT screw creates a caudo-cephalad path in sagittal plane and a medio-lateral path in axial plane, and engages cortical bone in the pedicle. The theoretical advantage is that it provides enhanced screw grip and interface strength. Midline lumbar fusion (MIDLF) is composed of posterior mid-line approach, microsurgical laminectomy, and CBT screw fixation. We adopted the MIDLF technique for lumbar spondylolisthesis. Advantages of this technique include that decompression and fusion are available in the same field, and it minimizes approach-related damages. To determine whether MIDLF with CBT screw is as effective as traditional approach and it is minimum invasive technique, we studied the clinical and radiological outcomes of MIDLF. Our results indicate that MIDLF is effective and minimum invasive technique. Evidence of effectiveness of MIDLF is that patients had good recovery score, and that CBT screw technique was safety in clinical and stable in radiological. MIDLF with CBT screw provides the surgeon with additional options for fixation. This technique is most likely to be useful for treating lumbar spondylolisthesis in combination with midline decompression and insertion of an interbody graft, such as the transforaminal lumbar interbody fusion or posterior lumbar interbody fusion techniques. PMID:25169139

  20. Sensitivity of lumbar spine loading to anatomical parameters.

    PubMed

    Putzer, Michael; Ehrlich, Ingo; Rasmussen, John; Gebbeken, Norbert; Dendorfer, Sebastian

    2016-04-11

    Musculoskeletal simulations of lumbar spine loading rely on a geometrical representation of the anatomy. However, this data has an inherent inaccuracy. This study evaluates the influence of defined geometrical parameters on lumbar spine loading utilising five parametrised musculoskeletal lumbar spine models for four different postures. The influence of the dimensions of vertebral body, disc, posterior parts of the vertebrae as well as the curvature of the lumbar spine was studied. Additionally, simulations with combinations of selected parameters were conducted. Changes in L4/L5 resultant joint force were used as outcome variable. Variations of the vertebral body height, disc height, transverse process width and the curvature of the lumbar spine were the most influential. These parameters can be easily acquired from X-rays and should be used to morph a musculoskeletal lumbar spine model for subject-specific approaches with respect to bone geometry. Furthermore, the model was very sensitive to uncommon configurations and therefore, it is advised that stiffness properties of discs and ligaments should be individualised.

  1. Radiographic Morphometry of the Lumbar Spine in Munich Miniature Pigs†

    PubMed Central

    Engelke, Elisabeth C; Post, Christina; Pfarrer, Christiane D; Sager, Martin; Waibl, Helmut R

    2016-01-01

    The incidence of human spinal column disease remains high, and animal models still play important roles in prophylactic, diagnostic, and therapeutic research. Because of their similar size to humans, pigs remain an important spine model. For pigs to serve as a model for the human spine, basic similarities and differences must be understood. In this study, morphometric data of the lumbar spine of Munich miniature pigs (Troll) were recorded radiologically, evaluated, and compared with recorded human data. Whereas humans have a constant number of 5 lumbar vertebrae, Munich minipigs had 5 or 6 lumbar vertebrae. Compared with their human counterparts, the lumbar vertebral bodies of the minipigs were remarkably larger in the craniocaudal (superior–inferior) direction and considerably smaller in the dorsoventral and laterolateral directions. The porcine vertebral canal was smaller than the human vertebral canal. The spinal cord extended into the caudal part of the porcine lumbar vertebral canal and thus did not terminate as cranial, as seen in humans. The lumbar intervertebral spaces of the pig were narrower in craniocaudal direction than human intervertebral spaces. These differences need to be considered when planning surgical actions, not only to avoid pain and irreversible damage to the minipigs but also to achieve accurate scientific results. PMID:27177570

  2. RINGED ACCRETION DISKS: EQUILIBRIUM CONFIGURATIONS

    SciTech Connect

    Pugliese, D.; Stuchlík, Z. E-mail: zdenek.stuchlik@physics.cz

    2015-12-15

    We investigate a model of a ringed accretion disk, made up by several rings rotating around a supermassive Kerr black hole attractor. Each toroid of the ringed disk is governed by the general relativity hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. Properties of the tori can then be determined by an appropriately defined effective potential reflecting the background Kerr geometry and the centrifugal effects. The ringed disks could be created in various regimes during the evolution of matter configurations around supermassive black holes. Therefore, both corotating and counterrotating rings have to be considered as being a constituent of the ringed disk. We provide constraints on the model parameters for the existence and stability of various ringed configurations and discuss occurrence of accretion onto the Kerr black hole and possible launching of jets from the ringed disk. We demonstrate that various ringed disks can be characterized by a maximum number of rings. We present also a perturbation analysis based on evolution of the oscillating components of the ringed disk. The dynamics of the unstable phases of the ringed disk evolution seems to be promising in relation to high-energy phenomena demonstrated in active galactic nuclei.

  3. Ring closure in actin polymers

    NASA Astrophysics Data System (ADS)

    Sinha, Supurna; Chattopadhyay, Sebanti

    2017-03-01

    We present an analysis for the ring closure probability of semiflexible polymers within the pure bend Worm Like Chain (WLC) model. The ring closure probability predicted from our analysis can be tested against fluorescent actin cyclization experiments. We also discuss the effect of ring closure on bend angle fluctuations in actin polymers.

  4. DC-Powered Jumping Ring

    ERIC Educational Resources Information Center

    Jeffery, Rondo N.; Farhang, Amiri

    2016-01-01

    The classroom jumping ring demonstration is nearly always performed using alternating current (AC), in which the ring jumps or flies off the extended iron core when the switch is closed. The ring jumps higher when cooled with liquid nitrogen (LN2). We have performed experiments using DC to power the solenoid and find similarities and significant…

  5. Uranus: the rings are black.

    PubMed

    Sinton, W M

    1977-11-04

    An upper limit of 0.05 is established for the geometric albedo of the newly discovered rings of Uranus. In view of this very low albedo, the particles of the rings cannot be ice-covered as are those of rings A and B of Saturn.

  6. Satellite Rings Movie

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This brief movie clip (of which the release image is a still frame), taken by NASA's Cassini spacecraft as it approached Jupiter, shows the motions, over a 16 hour-period, of two satellites embedded in Jupiter's ring. The moon Adrastea is the fainter of the two, and Metis the brighter. Images such as these will be used to refine the orbits of the two bodies.

    The movie was made from images taken during a 40-hour sequence of the Jovian ring on December 11, 2000.

    Cassini is a cooperative mission of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages Cassini for NASA's Office of Space Science, Washington, D.C.

  7. Saturn Ring Observer

    NASA Technical Reports Server (NTRS)

    Spilker, T. R.

    2001-01-01

    Answering fundamental questions about ring particle characteristics, and individual and group behavior, appears to require close-proximity (a few km) observations. Saturn's magnificent example of a ring system offers a full range of particle sizes, densities, and behaviors for study, so it is a natural choice for such detailed investigation. Missions implementing these observations require post-approach Delta(V) of approximately 10 km/s or more, so past mission concepts called upon Nuclear Electric Propulsion. The concept described here reduces the propulsive Delta(V) requirement to as little as 3.5 km/s, difficult but not impossible for high-performance chemical propulsion systems. Additional information is contained in the original extended abstract.

  8. Strained Ring Energetic Binders

    DTIC Science & Technology

    1993-08-27

    polyhomobenzvalene ( PHBV ). PHBV was not found to have the mechanical instability problems of PBV, but was still thermally unstable (Tonset - 660C, Tmax - 1090C...DISCUSSION 4 Polybenzvalene (PBV) 4 Polyhomobenzvalene ( PHBV ) 6 Chain-Transfer Studies 11 CONCLUSIONS 15 EXPERIMENTAL PROCEDURES 16 .F 4E 19 APPENDICES A...strained ring polymers similar to PBV are known. The investigation of one of these polymers, polyhomobenzvalene ( PHBV ), is also described in this report

  9. Which Ringed Planet...!?

    NASA Astrophysics Data System (ADS)

    2002-12-01

    Don't worry - you are not the only one who thought this was a nice amateur photo of planet Saturn, Lord of the Rings in our Solar System! But then the relative brightness and positions of the moons may appear somewhat unfamiliar... and the ring system does look unusually bright when compared to the planetary disk...?? Well, it is not Saturn, but Uranus , the next giant planet further out, located at a distance of about 3,000 million km, or 20 times the distance between the Sun and the Earth. The photo shows Uranus surrounded by its rings and some of the moons, as they appear on a near-infrared image that was obtained in the K s -band (at wavelength 2.2 µm) with the ISAAC multi-mode instrument on the 8.2-m VLT ANTU telescope at the ESO Paranal Observatory (Chile) . The exposure was made on November 19, 2002 (03:00 hrs UT) during a planetary research programme. The observing conditions were excellent (seeing 0.5 arcsec) and the exposure lasted 5 min. The angular diameter of Uranus is about 3.5 arcsec. The observers at ISAAC were Emmanuel Lellouch and Thérése Encrenaz of the Observatoire de Paris (France) and Jean-Gabriel Cuby and Andreas Jaunsen (both ESO-Chile). The rings The rings of Uranus were discovered in 1977, from observations during a stellar occultation event by astronomer teams at the Kuiper Airborne Observatory (KAO) and the Perth Observatory (Australia). Just before and after the planet moved in front of the (occulted) star, the surrounding rings caused the starlight to dim for short intervals of time. Photos obtained from the Voyager-2 spacecraft in 1986 showed a multitude of very tenuous rings. These rings are almost undetectable from the Earth in visible light. However, on the present VLT near-infrared picture, the contrast between the rings and the planet is strongly enhanced. At the particular wavelength at which this observation was made, the infalling sunlight is almost completely absorbed by gaseous methane present in the planetary atmosphere

  10. Precooler Ring Vacuum System

    SciTech Connect

    Moenich, J.

    1980-10-02

    The precooler vacuum system, as proposed by FNAL, is based on a suitable modification of the existing Electron Cooling Ring System. Because of the magnetic cycle of the bending magnets, distributed ion pumping, as exists in the Electron Cooling Ring, is not applicable. Instead, the proposed pumping will be done with commercial appendage ion pumps mounted approximately every two meters around the circumference of the ring. The loss of effective pumping speed and non-uniformity of system pressure with appendage pumps may not be major considerations but the large number required does effect experimental and analytical equipment placement considerations. There is a distributed pumping technique available which: (1) is not affected by the magnetic cycle of the bending magnets; (2) will provide a minimum of four times the hydrogen pumping speed of the proposed appendage ion pumps; (3) will require no power during pumping after the strip is activated; (4) will provide the heat source for bakeout; (5) is easily replaceable; and (6) can be purchased, installed, and operated at a generous economic advantage over the presently proposed ion pumped system. The pumping technique referred to is non-evaporable gettering with ST101 Zr/Al pumping strip. A technical description of this pumping strip is given on Data Sheet 1 and 2 attached to this report.

  11. Biomechanical effect of altered lumbar lordosis on intervertebral lumbar joints during the golf swing: a simulation study.

    PubMed

    Bae, Tae Soo; Cho, Woong; Kim, Kwon Hee; Chae, Soo Won

    2014-11-01

    Although the lumbar spine region is the most common site of injury in golfers, little research has been done on intervertebral loads in relation to the anatomical-morphological differences in the region. This study aimed to examine the biomechanical effects of anatomical-morphological differences in the lumbar lordosis on the lumbar spinal joints during a golf swing. The golf swing motions of ten professional golfers were analyzed. Using a subject-specific 3D musculoskeletal system model, inverse dynamic analyses were performed to compare the intervertebral load, the load on the lumbar spine, and the load in each swing phase. In the intervertebral load, the value was the highest at the L5-S1 and gradually decreased toward the T12. In each lumbar spine model, the load value was the greatest on the kypholordosis (KPL) followed by normal lordosis (NRL), hypolordosis (HPL), and excessive lordosis (EXL) before the impact phase. However, results after the follow-through (FT) phase were shown in reverse order. Finally, the load in each swing phase was greatest during the FT phase in all the lumbar spine models. The findings can be utilized in the training and rehabilitation of golfers to help reduce the risk of injury by considering individual anatomical-morphological characteristics.

  12. Saturn's ``Gossamer'' Ring: The F Ring's Inner Sheet

    NASA Astrophysics Data System (ADS)

    Showalter, M. R.; Burns, J. A.; Hamilton, D. P.

    1998-09-01

    Recent Galileo and Earth-based images have revealed for the first time that Jupiter's ``gossamer'' ring is actually composed of two rings, one bounded at the outer edge by Amalthea and the other bounded by Thebe. Dynamical models suggest that these rings are composed of dust grains ejected off the surfaces of the two moons, which then evolve inward under Poynting-Robertson drag. A very faint sheet of material filling the region between Saturn's A and F Rings reported by Burns et al. (BAAS 15, 1013--1014, 1983) may be a dynamically analogous system, in which dust escapes from the F Ring and evolves inward to the A Ring. Unlike Jupiter's gossamer rings, however, the inner sheet of Saturn's F Ring has been well observed from a large range of phase angles and visual wavelengths by Voyager. Voyager images reveal that this faint ring shows a tenfold increase in brightness between phase angles of 125(deg) and 165(deg) , indicating that it is composed of fine dust microns in size. Preliminary estimates of the normal optical depth fall in the range 1--2*E(-4) , depending on the dust size distribution assumed. Initial spectrophotometry reveals that the ring is neutral in color. The ring is uniform in brightness over the entire region between the two rings, with no evidence for internal structure associated with Prometheus and Atlas, suggesting that neither of these embedded moons acts as either a source or a sink. We will refine the aforementioned measurements and develop photometric models to better constrain the properties of the dust in this ring. This will enable us to relate the dust population to that in the F Ring proper, and to better explore the dynamical processes at work.

  13. Management of lumbar zygapophysial (facet) joint pain

    PubMed Central

    Manchikanti, Laxmaiah; Hirsch, Joshua A; Falco, Frank JE; Boswell, Mark V

    2016-01-01

    AIM: To investigate the diagnostic validity and therapeutic value of lumbar facet joint interventions in managing chronic low back pain. METHODS: The review process applied systematic evidence-based assessment methodology of controlled trials of diagnostic validity and randomized controlled trials of therapeutic efficacy. Inclusion criteria encompassed all facet joint interventions performed in a controlled fashion. The pain relief of greater than 50% was the outcome measure for diagnostic accuracy assessment of the controlled studies with ability to perform previously painful movements, whereas, for randomized controlled therapeutic efficacy studies, the primary outcome was significant pain relief and the secondary outcome was a positive change in functional status. For the inclusion of the diagnostic controlled studies, all studies must have utilized either placebo controlled facet joint blocks or comparative local anesthetic blocks. In assessing therapeutic interventions, short-term and long-term reliefs were defined as either up to 6 mo or greater than 6 mo of relief. The literature search was extensive utilizing various types of electronic search media including PubMed from 1966 onwards, Cochrane library, National Guideline Clearinghouse, clinicaltrials.gov, along with other sources including previous systematic reviews, non-indexed journals, and abstracts until March 2015. Each manuscript included in the assessment was assessed for methodologic quality or risk of bias assessment utilizing the Quality Appraisal of Reliability Studies checklist for diagnostic interventions, and Cochrane review criteria and the Interventional Pain Management Techniques - Quality Appraisal of Reliability and Risk of Bias Assessment tool for therapeutic interventions. Evidence based on the review of the systematic assessment of controlled studies was graded utilizing a modified schema of qualitative evidence with best evidence synthesis, variable from level I to level V

  14. Helmet latching and attaching ring

    NASA Technical Reports Server (NTRS)

    Chase, E. W.; Viikinsalo, S. J. (Inventor)

    1970-01-01

    A neck ring releasably secured to a pressurized garment carries an open-ended ring normally in the engagement position fitted into an annular groove and adapted to fit into a complementary annular groove formed in a helmet. Camming means formed on the inner surface at the end of the helmet engages the open-ended ring to retract the same and allow for one motion donning even when the garment is pressurized. A projection on the end of the split ring is engageable to physically retract the split ring.

  15. Mass of Saturn's A ring

    NASA Technical Reports Server (NTRS)

    Horn, L. J.; Russell, C. T.

    1993-01-01

    The mass of Saturn's A ring is reestimated using the behavior of spiral density waves embedded in the ring. The Voyager photopolarimeter (PPS) observed the star delta-Scorpii as it was occulted by Saturn's rings during the Voyager 2 flyby of Saturn in 1981 producing a radial profile of the rings. We examined forty spiral density waves in the Voyager PPS data of the A ring including 10 weaker waves that have not been previously analyzed by means of an autoregressive power spectral technique called Burg. The strengths of this new method for ring studies are that weaker, less extended waves are easily detected and characterized. This method is also the first one which does not require precise knowledge of the resonance location and phase of the wave in order to calculate the surface mass density. Uncertainties of up to 3 km are present in the currently available radial scales for Saturn's rings.

  16. A season in Saturn's rings: Cycling, recycling and ring history

    NASA Astrophysics Data System (ADS)

    Esposito, L. W.; Meinke, B. K.; Albers, N.; Sremcevic, M.

    2012-04-01

    Cassini experiments have watched Saturn's ring system evolve before our eyes. Images and occultations show changes and transient events. The rings are a dynamic and complex geophysical system, incompletely modeled as a single-phase fluid. Key Cassini observations: High resolution images show straw, propellers, embedded moonlets, and F ring objects. Multiple UVIS, RSS and VIMS occutlations indicate multimodal ringlet and edge structure, including free and forced modes along with stochastic perturbations that are most likely caused by nearby mass concentrations. Vertical excursions are evident at ring edges and in other perturbed regions. The rings are occasionally hit by meteorites that leave a signature that may last centuries; meteoritic dust pollutes the rings. Temperature, reflectance and transmission spectra are influenced by the dynamical state of the ring particles. Saturn's Equinox 2009: Oblique lighting exposed vertical structure and embedded objects. The rings were the coldest ever. Images inspired new occultation and spectral analysis that show abundant structure in the perturbed regions. The rings are more variable and complex than we had expected prior to this seasonal viewing geometry. Sub-kilometer structure in power spectral analysis: Wavelet analysis shows features in the strongest density waves and at the shepherded outer edge of the B ring. Edges are variable as shown by multiple occultations and occultations of double stars. F ring kittens: 25 features seen in the first 102 occultations show a weak correlation with Prometheus location. We interpret these features as temporary aggregations. Simulation results indicate that accretion must be enhanced to match the kittens' size distribution. Images show that Prometheus triggers the formation of transient objects. Propellers and ghosts: Occulations and images provide evidence for small moonlets in the A, B and C rings. These indicate accretion occurs inside the classical Roche limit. Implications

  17. Lumbar spine postures in marines during simulated operational positions.

    PubMed

    Berry, David B; Rodríguez-Soto, Ana E; Su, Jeannie; Gombatto, Sara P; Shahidi, Bahar; Palombo, Laura; Chung, Christine; Jensen, Andrew; Kelly, Karen R; Ward, Samuel R

    2017-01-04

    Low back pain has a 70% higher prevalence in members of the armed forces than in the general population, possibly due to the loads and positions soldiers experience during training and combat. Although the influence of heavy load carriage on standing lumbar spine posture in this population is known, postures in other operationally relevant positions are unknown. Therefore, the purpose of this study was to characterize the effect of simulated military operational positions under relevant loading conditions on global and local lumbar spine postures in active duty male US Marines. Secondary objectives were to evaluate if intervertebral disc degeneration and low back pain affect lumbar spine postures. Magnetic resonance images were acquired on an upright scanner in the following operational positions: Natural standing with no external load, standing with body armor (11.3 kg), sitting with body armor, and prone on elbows with body armor. Custom software was used to measure global lumbar spine posture: Lumbosacral flexion, sacral slope, lordosis, local measures of intervertebral angles, and intervertebral distances. Sitting resulted in decreased lumbar lordosis at all levels of the spine except L1-L2. When subjects were prone on elbows, a significant increase in local lordosis was observed only at L5-S1 compared with all other positions. Marines with disc degeneration (77%) or history of low back pain (72%) had decreased lumbar range of motion and less lumbar extension than healthy Marines. These results indicate that a male Marine's pathology undergoes a stereotypic set of postural changes during functional tasks, which may impair performance. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 9999:XX-XX, 2017.

  18. Hepatocellular Carcinoma Supplied by the Right Lumbar Artery

    SciTech Connect

    Miyayama, Shiro Yamashiro, Masashi; Okuda, Miho; Yoshie, Yuichi; Sugimori, Natsuki; Igarashi, Saya; Nakashima, Yoshiko; Matsui, Osamu

    2010-02-15

    This study evaluated the clinical features of hepatocellular carcinoma (HCC) supplied by the right lumbar artery. Eleven patients with HCC supplied by the right lumbar artery were treated with chemoembolization. The patients' medical records were retrospectively analyzed. All patients underwent 6.7 {+-} 3.7 (mean {+-} SD) chemoembolization sessions, and the hepatic arterial branches were noted as being attenuated. The right inferior phrenic artery (IPA) was also embolized in 10 patients. The interval between initial chemoembolization and chemoembolization of the lumbar artery supply was 53.2 {+-} 26.9 months. Mean tumor diameter was 3.1 {+-} 2.4 cm and was located at the surface of S7 and S6. The feeding-branch arose proximal to the bifurcation of the dorsal ramus and muscular branches (n = 8) or from the muscular branches (n = 3) of the right first (n = 10) or second lumbar artery (n = 1). The anterior spinal artery originated from the tumor-feeding lumbar artery in one patient. All feeders were selected, and embolization was performed after injection of iodized oil and anticancer drugs (n = 10) or gelatin sponge alone in a patient with anterior spinal artery branching (n = 1). Eight patients died from tumor progression 10.1 {+-} 4.6 months later, and two patients survived 2 and 26 months, respectively. The remaining patient died of bone metastases after 32 months despite liver transplantation 10 months after chemoembolization. The right lumbar artery supplies HCC located in the bare area of the liver, especially in patients who undergo repeated chemoembolization, including chemoembolization by way of the right IPA. Chemoembolization by way of the right lumbar artery may be safe when the feeder is well selected.

  19. New Views of Jupiter's Rings

    NASA Astrophysics Data System (ADS)

    Burns, J. A.

    1998-09-01

    Jupiter's rings are the archetype of ethereal planetary rings (very-low optical-depth bands containing micron-sized "dust"). As a result of much improved observations by Galileo (Ockert-Bell* -- most citations are et al. and Icarus in press* or this meeting) and Keck (de Pater*), we now understand the nature of such rings. The ring has three components: a 104 km-thick toroidal halo (1.4-1.7 RJ; normal optical depth t = 10-6), a thin main ring (1.7-1.8 RJ; t = 10-6), and a pair of exterior gossamer rings (1.8-3.5RJ; t = 10-7). The main ring has patchy ( 20-30 percent) brightness. The ring is reddish and its particles satisfy a -2.5 differential power-law size distribution. Because particle lifetimes are brief, the rings must be continually regenerated, by collisions into parent bodies, which may be unseen or may be the known small ring-moons (Thomas*, Simonelli). The gossamer ring seems to be collisional ejecta derived from the ring-moons Amalthea and Thebe, and evolving inward by Poynting-Robertson drag (Burns). The particles drift through many electromagnetic resonances, clustering around synchronous orbit, which produce jumps in the particles' inclinations (Hamilton). The main ring is probably debris from Adrastea and Metis, which orbit in the equatorial plane. The halo particles are driven vertically by electromagnetic forces, which may be resonant (Schaffer & Burns) or not (Horanyi & Cravens). When halo orbits become highly distorted, particles are lost into Jupiter. Similar faint rings may be attendant to all small, close-in satellites (Showalter).

  20. Osteolytic lumbar discal cyst: case report.

    PubMed

    Marushima, Aiki; Uemura, Kazuya; Sato, Naoaki; Maruno, Toru; Matsumura, Akira

    2008-08-01

    A 25-year-old man presented with left lumboischialgia refractory to medical treatment. Neurological examination revealed L5 and S1 radiculopathy which rapidly worsened over a short period. Magnetic resonance imaging demonstrated disk bulging with a discal cyst at the L4-5 intervertebral space and disk herniation at the L5-S1 intervertebral space. Computed tomography showed osteolytic change of the L5 vertebral body adjacent to the cyst. Resection of the cyst and removal of the herniated disk were performed following fenestration of the L4-5 and L5-S1 interlaminar spaces. Bloody serous fluid followed by clear serous fluid was recognized during the aspiration and partial resection of the cyst at the L4-5 level. Histological examination demonstrated a cyst wall consisting of fibrous connective tissue without a single-layer lining of cells, and fibrin deposits. The patient's symptoms disappeared immediately after the operation. This osteolytic lumbar discal cyst possibly occurred subsequent to hemorrhage from the epidural venous plexus following intervertebral disk injury, hematoma encapsulation by connective fibrous tissue, and cyst wall formation in reaction to the disk injury and hemorrhage. The cyst may have enlarged due to the inflow of the serous fluid from the water-containing degenerated disk.

  1. Lumbar Disc Herniation Presented with Contralateral Symptoms

    PubMed Central

    Kim, Pius; Ju, Chang Il; Kim, Hyeun Sung; Kim, Seok Won

    2017-01-01

    Objective This study aimed to unravel the putative mechanism underlying the neurologic deficits contralateral to the side with lumbar disc herniation (LDH) and to elucidate the treatment for this condition. Methods From January 2009 to June 2015, 8 patients with LDH with predominantly contralateral neurologic deficits underwent surgical treatment on the side with LDH with or without decompressing the symptomatic side. A retrospective review of charts and radiological records of these 8 patients was performed. The putative mechanisms underlying the associated contralateral neurological deficits, magnetic resonance imaging (MRI), electromyography (EMG), and the adequate surgical approach are discussed here. Results MRI revealed a similar laterally skewed paramedian disc herniation, with the apex deviated from the symptomatic side rather than directly compressing the nerve root; this condition may generate a contralateral traction force. EMG revealed radiculopathies in both sides of 6 patients and in the herniated side of 2 patients. Based on EMG findings and the existence of suspicious lateral recess stenosis of the symptomatic side, 6 patients underwent bilateral decompression of nerve roots and 2 were subjected to a microscopic discectomy to treat the asymptomatic disc herniation. No specific conditions such as venous congestion, nerve root anomaly or epidural lipomatosis were observed, which may be considered the putative pathomechanism causing the contralateral neurological deficits. The symptoms resolved significantly after surgery. Conclusion The traction force generated on the contralateral side and lateral recess stenosis, rather than direct compression, may cause the contralateral neurologic deficits observed in LDH. PMID:28264243

  2. Movements, lumbar and temporomandibular pain and psychopathology.

    PubMed

    Sundsvold, M O; Vaglum, P; Ostberg, B

    1981-01-01

    157 males and females divided into four psychodiagnostic groups have been examined according to a specially defined physiotherapeutic (ad modum Sundsvold). In this paper, results from the evaluation of passive and active movements in five body significant differences concerning inhibited movements between the four groups were found, the psychotic group being most inhibited followed by the ego-week neurotic group, the substance-abusing group and the healthy control group. With regard to the slack movements, significant differences were found in the two extremity regions. The substance-abusing group had the most slack movements, next came the ego-weak neurotic group, the psychotic group and lastly the control group. Men were more inhibited than women in three regions, mostly in the lumbosacral region. This finding is discussed in relationship to the high frequency of lumbar disc herniation in men. Women were more significantly inhibited in the temporomandibular region, a finding which may explain why mostly women are suffering from the myofacial pain syndrome.

  3. Lubrication regimes in lumbar total disc arthroplasty.

    PubMed

    Shaheen, A; Shepherd, D E T

    2007-08-01

    A number of total disc arthroplasty devices have been developed. Some concern has been expressed that wear may be a potential failure mode for these devices, as has been seen with hip arthroplasty. The aim of this paper was to investigate the lubrication regimes that occur in lumbar total disc arthroplasty devices. The disc arthroplasty was modelled as a ball-and-socket joint. Elastohydrodynamic lubrication theory was used to calculate the minimum film thickness of the fluid between the bearing surfaces. The lubrication regime was then determined for different material combinations, size of implant, and trunk velocity. Disc arthroplasties with a metal-polymer or metal-metal material combination operate with a boundary lubrication regime. A ceramic-ceramic material combination has the potential to operate with fluid-film lubrication. Disc arthroplasties with a metal-polymer or metal-metal material combination are likely to generate wear debris. In future, it is worth considering a ceramic-ceramic material combination as this is likely to reduce wear.

  4. Risk Factors for Recurrent Lumbar Disc Herniation

    PubMed Central

    Huang, Weimin; Han, Zhiwei; Liu, Jiang; Yu, Lili; Yu, Xiuchun

    2016-01-01

    Abstract Recurrent lumbar disc herniation (rLDH) is a common complication following primary discectomy. This systematic review aimed to investigate the current evidence on risk factors for rLDH. Cohort or case-control studies addressing risk factors for rLDH were identified by search in Pubmed (Medline), Embase, Web of Science, and Cochrane library from inception to June 2015. Relevant results were pooled to give overall estimates if possible. Heterogeneity among studies was examined and publication bias was also assessed. A total of 17 studies were included in this systematic review. Risk factors that had significant relation with rLDH were smoking (OR 1.99, 95% CI 1.53–2.58), disc protrusion (OR 1.79, 95% CI 1.15–2.79), and diabetes (OR 1.19, 95% CI 1.06–1.32). Gender, BMI, occupational work, level, and side of herniation did not correlate with rLDH significantly. Based on current evidence, smoking, disc protrusion, and diabetes were predictors for rLDH. Patients with these risk factors should be paid more attention for prevention of recurrence after primary surgery. More evidence provided by high-quality observational studies is still needed to further investigate risk factors for rLDH. PMID:26765413

  5. Tree Rings: Timekeepers of the Past.

    ERIC Educational Resources Information Center

    Phipps, R. L.; McGowan, J.

    One of a series of general interest publications on science issues, this booklet describes the uses of tree rings in historical and biological recordkeeping. Separate sections cover the following topics: dating of tree rings, dating with tree rings, tree ring formation, tree ring identification, sample collections, tree ring cross dating, tree…

  6. Transition of a herniated lumbar disc to lumbar discal cyst: A case report

    PubMed Central

    Bansil, Rohit; Hirano, Yoshitaka; Sakuma, Hideo; Watanabe, Kazuo

    2016-01-01

    Background: Another rare cause of lower back pain with radiculopathy is the discal cyst. It is believed to arise from degeneration of a herniated disc, although many other theories of its origin have been proposed. Here, we report a patient with lower back pain/radiculopathy attributed originally to a herniated lumbar disc, which transformed within 6 months into a discal cyst. Case Description: A 42-year-old male had a magnetic resonance (MR) documented herniated lumbar disc at the L4-5 level. It was managed conservatively for 6 months, after which symptoms recurred and progressed. The follow-up MR study revealed a discal cyst at the L4-5 without residual herniated disc. Of interest, the cyst communicated with the L4-5 intervertebral disc, which was herniated under the posterior longitudinal ligament and the disc space. During surgery, the cyst was completely removed, and his symptoms/signs resolved. Conclusion: A discal cyst develops as pathological sequelae of a degenerated herniated disc. Although rare, these lesions must be considered among the differential diagnoses in young patients with radicular back pain. MR study clearly documents these lesions, and surgical excision of the cyst is the treatment of choice. PMID:27843689

  7. Ring currents in azulene

    NASA Astrophysics Data System (ADS)

    Paxton, A. T.; Todorov, T. N.; Elena, A. M.

    2009-11-01

    We propose a self consistent polarisable ion tight binding theory for the study of push-pull processes in aromatic molecules. We find that the method quantitatively reproduces ab initio calculations of dipole moments and polarisability. We apply the scheme in a simulation which solves the time dependent Schrödinger equation to follow the relaxation of azulene from the second excited to the ground states. We observe rather spectacular oscillating ring currents which we explain in terms of interference between the HOMO and LUMO states.

  8. Wave structure in planetary rings

    NASA Astrophysics Data System (ADS)

    Horn, Linda Joyce

    1992-01-01

    Planetary rings contain a wealth of wavelike structure that is driven by gravitational resonance interactions with nearby satellites. Wave behavior is a powerful tool for estimating physical ring parameters that are key to our understanding of ring origin and evolution. A new technique, utilizing the Burg autoregressive power spectral algorithm, was developed for probing the physical characteristics of rings and for detecting waves that are not otherwise visible. Data from the Voyager photopolarimeter (PPS) stellar occultations by the rings of Saturn, Uranus, and Neptune and the Voyager radio science (RSS) occultation by Saturn's rings were used. Local surface mass density estimates are obtained from the dispersion of 40 spiral density waves in Saturn's A ring, including 10 weaker waves not previously analyzed. Surface mass densities vary from 20 to 60 gm sq cm. Increasing optical depth is not correlated with increasing surface mass density, especially after the Keeler gap, suggesting that ring particle size and composition are not uniform throughout the A ring. Saturn's A ring mass is reestimated using the surface mass densities and is 5.2 +/- 1.3 x 1021 gm. The wakes of Saturn's satellite Pan are not short timescale phenomena because the effects of Pan's gravitational perturbations persist for more than one Pan encounter. Four additional Pan wakes were discovered at longitudes greater than 360 deg. Collective effects such as collisions modify the wake dispersion more extensively at greater longitudes. Pan is the dominant mass in the Encke gap. A spiral density wave was detected inside the Uranian delta ring. Upper and lower bounds were estimated for the surface mass density of the delta ring 5 less than or equal to sigma less than or equal to 10 gm/sq cm, the viscosity 10 less than or equal to nu less than or equal to 40 sq cm/sec, and the local ring height 7 less than or equal to h less than or equal to 20 m. These values are comparable to the corresponding

  9. Comparison of outcomes between minimally invasive transforaminal lumbar interbody fusion and traditional posterior lumbar intervertebral fusion in obese patients with lumbar disk prolapse

    PubMed Central

    Wang, Ya-Peng; An, Ji-Long; Sun, Ya-Peng; Ding, Wen-Yuan; Shen, Yong; Zhang, Wei

    2017-01-01

    Objective The aim of this study was to compare the curative effect between minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and the posterior lumbar interbody fusion (PLIF) in obese patients with lumbar disk prolapse. Patients and methods In this study, 72 patients who underwent lumbar disk prolapse therapy in the Third Hospital of Hebei Medical University between March 2011 and 2015 were retrospectively analyzed and were divided into two groups, MIS-TLIF group (n=35) and PLIF group (n=37), according to different surgical procedures. Several clinical parameters were compared between these two groups. Results Compared with PLIF, MIS-TLIF was associated with longer operative time, less blood loss, less postoperative drainage and shorter postoperative time in bed; moreover, patients in the MIS-TLIF group had lower levels of serum creatine kinase on 1, 3 and 5 postoperative days. At the 3- and 6-month follow-up, Visual Analog Scale (VAS) scores of low back pain of patients in the MIS-TLIF group were significantly reduced and Japanese Orthopaedic Association (JOA) scores were increased, whereas the Oswestry Disability Index (ODI) showed no significant difference between the two groups. Conclusion Obese patients can achieve good efficacy with MIS-TLIF or PLIF treatment, but MIS-TLIF surgery showed longer operative time, fewer traumas and bleeding volume, less incidence of short-term pain, low complication rate and faster postoperative recovery. PMID:28176906

  10. Is lumbar facet fusion biomechanically equivalent to lumbar posterolateral onlay fusion?

    PubMed

    Toth, Jeffrey M; Foley, Kevin T; Wang, Mei; Seim, Howard B; Simon Turner, A

    2017-02-03

    OBJECTIVE This study was designed with the following research objectives: 1) to determine the efficacy of facet fusion with recombinant human bone morphogenetic protein-2 (rhBMP-2) on an absorbable collagen sponge (ACS) in an ovine lumbar facet fusion model; 2) to radiographically and histologically compare the efficacy of lumbar facet fusion with rhBMP-2/ACS to facet fusion with an iliac crest bone graft (ICBG); and 3) to biomechanically compare lumbar facet fusion with rhBMP-2/ACS to lumbar posterolateral fusion (PLF) with ICBG. METHODS The efficacies of the 3 treatments to induce fusion were evaluated in an instrumented ovine lumbar fusion model. Eight sheep had 10 cm(3)/side ICBG placed as an onlay graft for PLF at L2-3. At the adjacent L3-4 level, 0.5 cm(3)/side ICBG was placed for facet fusion. Finally, 0.5 cm(3)/side rhBMP-2/ACS (0.43 mg/ml) was placed for facet fusion at L4-5. CT scans were obtained at 2, 4, and 6 months postoperatively with 2 reviewers conducting an evaluation of the 6-month results for all treated spinal levels. All 8 sheep were killed at 6 months, and all posterolateral instrumentation was removed at this time. The spines were then sectioned through L3-4 to allow for nondestructive unconstrained biomechanical testing of the L2-3 and L4-5 segments. All treated spinal levels were analyzed using undecalcified histology with corresponding microradiography. Statistical comparisons were made between the treatment groups. RESULTS The PLF with ICBG (ICBG PLF group) and the rhBMP-2 facet fusion (rhBMP-2 Facet group) treatment groups demonstrated similar levels of stiffness, with the rhBMP-2 Facet group having on average slightly higher stiffness in all 6 loading directions. All 8 levels in the autograft facet fusion treatment group demonstrated CT radiographic and histological fusion. All 8 levels in the rhBMP-2 Facet group showed bilateral CT radiographic and histological fusion. Six of 16 rhBMP-2/ACS-treated facet defects demonstrated small

  11. The Charging of Planetary Rings

    NASA Astrophysics Data System (ADS)

    Graps, Amara L.; Horanyi, M.; Havnes, O.; Gruen, E.

    2008-09-01

    Planetary rings have an undeniable aesthetic appeal, resulting in media icons of ringed planets as descriptive of the planetary sciences field as a whole. Such far-reaching symbolism might not be misplaced, however, because planetary rings represent a fundamental class of planetary structure that invites interdisciplinary investigations from specialists in dust, gravitational, plasma, collisional, and radiative transfer physics, due to: its sub-micron to meters-sized particles, its immersion in the planet's magnetic field, its embedded moonlets and its close proximity to the ringed planet's ionosphere and innermost moons. As such, planetary rings are a metaphoric bridge through a wide range of planetary physical processes. Processes to charge ring particles have different relative dynamical effects, dependent upon the rings' particle sizes, and the ring's plasma, magnetic and gravitational environments. This presentation will review what is known about the charging parameters and processes of planetary rings, in particular the sum of the individual currents from the time-varying charge dQ/dt, of the planetary ring particle. The individual currents depend on the environmental plasma conditions: number density, flow speed, temperature, and mass for the currents: electron and ion capture from the plasma, ion currents to a moving grain, photoelectron emission, secondary electron emission, thermionic effects, with stochastic charging influencing all of the above. Since rings are an ensemble of particles, ("cloud" Ring), we will define an ensemble, and consider the above currents, including those for the smallest ring particles, the dust particles, to arrive at a table giving charge potential and other relevant parameters.

  12. Results of surgical lysis of lumbar adhesive arachnoiditis.

    PubMed

    Wilkinson, H A; Schuman, N

    1979-05-01

    From a series of 681 patients with lumbar disc disease treated between 1966 and 1978, 17 patients required surgical lysis of lumbar adhesive arachnoiditis, 8 having initially been operated upon by another surgeon. All patients had severe pain as a predominant feature, with pain being bilateral in 9 patients. Pain was the only major symptom in 3; the other 14 exhibited varying combinations of progressive neurological dysfunction. Three patients developed late symptoms after trauma, 8 to 21 years after back surgery. At operation, multisegmental arachnoiditis was found in 5 patients and anular or subtotal adhesions were found in 12. Complete lysis could not be obtained in 4 patients. Fourteen patients were treated with steroids at the time of operation. Follow-up after lysis was less than 1 year for 5 patients but averaged 4.8 years for the remaining 12. During the 1st year after operation, 76% experienced improvement in pain (35%, good to excellent), 71% experienced improvement in neurological status. Follow-up after at least 1 year revealed 50% still enjoying pain relief (25%, good to excellent) and 45% experiencing neurological improvement. Pain relief persisted in 4 of 5 patients followed 5 years or more. The etiological role of myelograpy and lumbar disc surgery in arachnoiditis has probably been over-rated. Arachnoiditis may be symptomatic or asymptomatic and may mask other, treatable lumbar lesions. More frequent intradural exploration for discrepancies between operative and myelographic findings might reveal, and benefit, more cases of spontaneous arachnoiditis mimicking lumbar disc disease.

  13. [Isokinetic and functional lumbar evaluation in workers pensioned with disability].

    PubMed

    Navarro-Trujillo, Luz Rocío; Mireles-Pérez, Ana Bárbara Isabel; Castañeda-Borrayo, Yaocihuatl; Plascencia-García, José Luis

    2013-01-01

    Introducción: en 2008 se formularon 13 371 dictámenes de invalidez en Jalisco, gran parte de ellos motivados por lesiones de la columna lumbar. La mayoría es de naturaleza definitiva y requiere evaluaciones completas de las capacidades lumbares. El objetivo de esta investigación fue evaluar la funcionalidad de la columna lumbar con el cuestionario de Oswestry y con el estudio isocinético en pensionados por lesiones lumbares. Métodos: estudio comparativo de 20 trabajadores con dictamen de invalidez por lesiones lumbares, a quienes se les solicitó realizar ejercicios isocinéticos y contestar el cuestionario de Oswestry. Resultados: con el cuestionario de Oswestry se determinó una discapacidad de 60 %. En cuanto a la evaluación isocinética, en la extensión se obtuvo un torque máximo de 44 Nw. En el trabajo fatiga se encontraron una media y una moda de cero. En la flexión, el torque máximo fue de -75.5 Nw. En la potencia, la moda fue de 40 V. En el trabajo-fatiga, la media y la moda fueron de cero. Conclusiones: la evaluación isocinética no fue normal en ninguno de los trabajadores, con lo que se corroboró la invalidez.

  14. Embolization of Isolated Lumbar Artery Injuries in Trauma Patients

    SciTech Connect

    Sofocleous, Constantinos T. Hinrichs, Clay R.; Hubbi, Basil; Doddakashi, Satish; Bahramipour, Philip; Schubert, Johanna

    2005-12-15

    Purpose. The purpose of the study was to evaluate the angiographic findings and results of embolotherapy in the management of lumbar artery trauma. Methods. All patients with lumbar artery injury who underwent angiography and percutaneous embolization in a state trauma center within a 10-year period were retrospectively reviewed. Radiological information and procedural reports were reviewed to assess immediate angiographic findings and embolization results. Long-term clinical outcome was obtained by communication with the trauma physicians as well as with chart review. Results. In a 10-year period, 255 trauma patients underwent abdominal aortography. Eleven of these patients (three women and eight men) suffered a lumbar artery injury. Angiography demonstrated active extravasation (in nine) and/or pseudoaneurysm (in four). Successful selective embolization of abnormal vessel(s) was performed in all patients. Coils were used in six patients, particles in one and gelfoam in five patients. Complications included one retroperitoneal abscess, which was treated successfully. One patient returned for embolization of an adjacent lumbar artery due to late pseudoaneurysm formation. Conclusions. In hemodynamically stable patients, selective embolization is a safe and effective method for immediate control of active extravasation, as well as to prevent future hemorrhage from an injured lumbar artery.

  15. Lumbar Stenosis: A Recent Update by Review of Literature

    PubMed Central

    Lee, Seung Yeop; Kim, Tae-Hwan; Oh, Jae Keun; Lee, Seung Jin

    2015-01-01

    Degeneration of the intervertebral disc results in initial relative instability, hypermobility, and hypertrophy of the facet joints, particularly at the superior articular process. This finally leads to a reduction of the spinal canal dimensions and compression of the neural elements, which can result in neurogenic intermittent claudication caused by venous congestion and arterial hypertension around nerve roots. Most patients with symptomatic lumbar stenosis had neurogenic intermittent claudication with the risk of a fall. However, although the physical findings and clinical symptoms in lumbar stenosis are not acute, the radiographic findings are comparatively severe. Magnetic resonance imaging is a noninvasive and good method for evaluation of lumbar stenosis. Though there are very few studies pertaining to the natural progression of lumbar spinal stenosis, symptoms of spinal stenosis usually respond favorably to non-operative management. In patients who fail to respond to non-operative management, surgical treatments such as decompression or decompression with spinal fusion are required. Restoration of a normal pelvic tilt after lumbar fusion correlates to a good clinical outcome. PMID:26435805

  16. Sympathetic radiofrequency neurolysis for unilateral lumbar hyperhidrosis: a case report.

    PubMed

    Aşik, Züleyha Soytürk; Orbey, Başak Ceyda; Aşik, Ibrahim

    2008-07-01

    Patients with hyperhidrosis suffer from physical, social and mental discomfort which often cannot be treated sufficiently using conservative measures. A new percutaneous approach to sympathectomy using radiofrequency denervation has seemed to offer longer duration of action and less incidence of post sympathetic neuralgia. This article reports the authors' experience with sympathetic RF neurolysis in a 35 year old male with right unilateral lumbar hyperhidrosis. Under scopy guided localization of the lumbar spine sympathetic blockade with local anesthetics to L2-5 vertebral levels were performed as a diagnostic block. Lesion effectiveness is monitored by bilateral feet skin temperature measurement. Clinical effects produced by the first sympathetic ganglion block were sustained for 1 week and then RF neurolysis of lumbar sympathetic ganglion was performed to the same levels for a longer effect. The procedure was accomplished within 30 minutes and the patient was discharged within 2 hours after the procedure. Hyperhidrosis was relieved after the procedure and there were no postsympathectomy neuralgia and sexual dysfunction. The patient obtained improvement of lumbar hyperhidrosis at his first month of follow- up and was satisfied with the outcome. In conclusion, RF neurolysis of lumbar sympathetic ganglions is a safe and effective palliative procedure with minimal invasiveness for relieving excessive sweat secretion in patients with localized hyperhidrosis.

  17. Importance of greenstick lamina fractures in low lumbar burst fractures

    PubMed Central

    Ersozlu, S.; Aydinli, U.

    2006-01-01

    Lumbar burst fractures (L3–L5) represent a small percentage of all spinal fractures. The treatment of fractures involving the lumbar spine has been controversial. Lamina fractures may be complete or of the greenstick type. Dural tears and nerve root entrapment may accompany these lamina fractures. The aim of this retrospective study was to determine the incidence of dural tear in patients who had lumbar burst fractures with greenstick lamina fractures and the importance of these lamina fractures when choosing the optimum treatment. Twenty-six patients with 28 lumbar burst fractures were treated from 1995 through 2002. The average follow-up was 60 months (range 32–110 months). The male to female ratio was 21:5 and the mean age was 37 years (17–64). Dural tear was detected in seven (25%) out of 28 burst fractures. The functional outcome of the entire study group was assessed using the Smiley-Webster Scale. Good to excellent results were obtained in 24 (92%) of 26 patients. Lumbar burst fractures with greenstick lamina fractures occur mostly in the L2–L4 area. In the surgical treatment, any reduction manoeuvre will close the fracture and crush the entrapped neural elements. Therefore, it may be better to explore the greenstick lamina fracture whether there is any neural entrapment or not, before any reduction manoeuvre is attempted. PMID:16501977

  18. Buoyant Norbury's vortex rings

    NASA Astrophysics Data System (ADS)

    Blyth, Mark; Rodriguez-Rodriguez, Javier; Salman, Hayder

    2014-11-01

    Norbury's vortices are a one-parameter family of axisymmetric vortex rings that are exact solutions to the Euler equations. Due to their relative simplicity, they are extensively used to model the behavior of real vortex rings found in experiments and in Nature. In this work, we extend the original formulation of the problem to include buoyancy effects for the case where the fluid that lies within the vortex has a different density to that of the ambient. In this modified formulation, buoyancy effects enter the problem through the baroclinic term of the vorticity equation. This permits an efficient numerical solution of the governing equation of motion in terms of a vortex contour method that tracks the evolution of the boundary of the vortex. Finally, we compare our numerical results with the theoretical analysis of the short-time evolution of a buoyant vortex. Funded by the Spanish Ministry of Economy and Competitiveness through grant DPI2011-28356-C03-02 and by the London Mathematical Society.

  19. Storage ring injection

    SciTech Connect

    Burke, R.J.

    1980-01-01

    Some basic issues involved in injecting the beam into storage rings with the principal parameters of those studied at the workshop have been considered. The main conclusion is that straightforward adjustments of the storage ring parameters makes injection easy. The largest number of injected turns is fourteen, and the phase space dilution allowance seems adequate to ensure very small beam loss during injection. The adjustments also result in lower bending magnet fields, and high field superconducting magnets (e.g., 5 Tesla) are not necessary. The design changes do not necessarily affect the Keil-Schnell criterion for stability of the longitudinal microwave instability, although that criterion appears to be irrelevant. Because the beams are expected to be unstable, but with slow growth rates, the vacuum chamber impedances required to give equal risetimes for the various designs are compared for systems posing various degrees of difficulty for injection. Finally, the impact of the parameters on cost is noted, and a system is considered that cuts the length of the linac in half by using doubly charged ions.

  20. Ring Image Analyzer

    NASA Technical Reports Server (NTRS)

    Strekalov, Dmitry V.

    2012-01-01

    Ring Image Analyzer software analyzes images to recognize elliptical patterns. It determines the ellipse parameters (axes ratio, centroid coordinate, tilt angle). The program attempts to recognize elliptical fringes (e.g., Newton Rings) on a photograph and determine their centroid position, the short-to-long-axis ratio, and the angle of rotation of the long axis relative to the horizontal direction on the photograph. These capabilities are important in interferometric imaging and control of surfaces. In particular, this program has been developed and applied for determining the rim shape of precision-machined optical whispering gallery mode resonators. The program relies on a unique image recognition algorithm aimed at recognizing elliptical shapes, but can be easily adapted to other geometric shapes. It is robust against non-elliptical details of the image and against noise. Interferometric analysis of precision-machined surfaces remains an important technological instrument in hardware development and quality analysis. This software automates and increases the accuracy of this technique. The software has been developed for the needs of an R&TD-funded project and has become an important asset for the future research proposal to NASA as well as other agencies.

  1. Ring current and radiation belts

    NASA Technical Reports Server (NTRS)

    Williams, D. J.

    1987-01-01

    Studies performed during 1983-1986 on the ring current, the injection boundary model, and the radiation belts are discussed. The results of these studies yielded the first observations on the composition and charge state of the ring current throughout the ring-current energy range, and strong observational support for an injection-boundary model accounting for the origins of radiation-belt particles, the ring current, and substorm particles observed at R less than about 7 earth radii. In addition, the results have demonstrated that the detection of energetic neutral atoms generated by charge-exchange interactions between the ring current and the hydrogen geocorona can provide global images of the earth's ring current and its spatial and temporal evolution.

  2. Reversible Rings with Involutions and Some Minimalities

    PubMed Central

    Fakieh, W. M.; Nauman, S. K.

    2013-01-01

    In continuation of the recent developments on extended reversibilities on rings, we initiate here a study on reversible rings with involutions, or, in short, ∗-reversible rings. These rings are symmetric, reversible, reflexive, and semicommutative. In this note we will study some properties and examples of ∗-reversible rings. It is proved here that the polynomial rings of ∗-reversible rings may not be ∗-reversible. A criterion for rings which cannot adhere to any involution is developed and it is observed that a minimal noninvolutary ring is of order 4 and that a minimal noncommutative ∗-reversible ring is of order 16. PMID:24489510

  3. Acute formation of lumbar discal cyst: what is the mechanism?

    PubMed

    Aydin, S; Kucukyuruk, B; Yildirim, H; Abuzayed, B; Bozkus, H; Vural, M

    2010-12-01

    Lumbar discal cysts are extremely rare pathologies, with only few reports describing these lesions in the literature. Moreover, their definite pathogenesis is still unknown, with proposed theories based on radialogic and histologic findings. In this report, the authors present an acute formation of a discal cyst, which is reported for the first time. Also, we center our case on the discussion of the possible pathogenesis. Also, this is the first case of discal cyst reported in Turkey. A 67-year-old woman, whose complaints, and clinical and radiological findings demonstrated lumbar disc herniation with acute Modic 1 degererative changes of the adjacent end plates of L3-4 level. After medical and physical therapies, follow-up lumbar MRI has been taken to demonstrate a discal cyst formation on the adjacent intervertebral disc, showed cranially migrated cyst superior posterior on herniated disc, in 2 weeks period. The patient was treated by microsurgical resection of the cyst, and her complaints resolved completely.

  4. Sex determination by discriminant function analysis of lumbar vertebrae.

    PubMed

    Ostrofsky, Kelly R; Churchill, Steven E

    2015-01-01

    Sex determination is critical for developing the biological profile of unidentified skeletal remains. When more commonly used elements (os coxa, cranium) for sexing are not available, methods utilizing other skeletal elements are needed. This study aims to assess the degree of sexual dimorphism of the lumbar vertebrae and develop discriminant functions for sex determination from them, using a sample of South African blacks from the Raymond A. Dart Collection (47 males, 51 females). Eleven variables at each lumbar level were subjected to univariate and multivariate discriminant function analyses. Univariate equations produced classification rates ranging from 57.7% to 83.5%, with the highest accuracies associated with dimensions of the vertebral body. Multivariate stepwise analysis generated classification rates ranging from 75.9% to 88.7%. These results are comparable to other methods for sexing the skeleton and indicate that measures of the lumbar vertebrae can be used as an effective tool for sex determination.

  5. Low back pain and lumbar angles in Turkish coal miners

    SciTech Connect

    Sarikaya, S.; Ozdolap, S.; Gumustas, S.; Koc, U.

    2007-02-15

    This study was designed to assess the incidence of low back pain among Turkish coal miners and to investigate the relationship between angles of the lumbar spine and low back pain in coal miners. Fifty underground workers (Group I) and 38 age-matched surface workers (Group II) were included in the study. All the subjects were asked about low back pain in the past 5 years. The prevalence of low back pain was higher in Group I than in Group II (78.0%, 32.4%, respectively, P {lt} 0.001). The results of the study showed that low back pain occurred in 78.0% of Turkish coal miners. Although the nature of the occupation may have influenced coal miners' lumbar spinal curvature, lumbar angles are not a determinant for low back pain in this population. Further extensive studies involving ergonomic measurements are needed to validate our results for Turkish coal mining industry.

  6. Multiexpandable cage for minimally invasive posterior lumbar interbody fusion

    PubMed Central

    Coe, Jeffrey D; Zucherman, James F; Kucharzyk, Donald W; Poelstra, Kornelis A; Miller, Larry E; Kunwar, Sandeep

    2016-01-01

    The increasing adoption of minimally invasive techniques for spine surgery in recent years has led to significant advancements in instrumentation for lumbar interbody fusion. Percutaneous pedicle screw fixation is now a mature technology, but the role of expandable cages is still evolving. The capability to deliver a multiexpandable interbody cage with a large footprint through a narrow surgical cannula represents a significant advancement in spinal surgery technology. The purpose of this report is to describe a multiexpandable lumbar interbody fusion cage, including implant characteristics, intended use, surgical technique, preclinical testing, and early clinical experience. Results to date suggest that the multiexpandable cage allows a less invasive approach to posterior/transforaminal lumbar interbody fusion surgery by minimizing iatrogenic risks associated with static or vertically expanding interbody prostheses while providing immediate vertebral height restoration, restoration of anatomic alignment, and excellent early-term clinical results. PMID:27729817

  7. Spontaneous Intracranial Hypotension Secondary to Lumbar Disc Herniation

    PubMed Central

    Kim, Kyoung-Tae

    2010-01-01

    Spontaneous intracranial hypotension is often idiopathic. We report on a patient presenting with symptomatic intracranial hypotension and pain radiating to the right leg caused by a transdural lumbar disc herniation. Magnetic resonance (MR) imaging of the brain revealed classic signs of intracranial hypotension, and an additional spinal MR confirmed a lumbar transdural herniated disc as the cause. The patient was treated with a partial hemilaminectomy and discectomy. We were able to find the source of cerebrospinal fluid leak, and packed it with epidural glue and gelfoam. Postoperatively, the patient's headache and log radiating pain resolved and there was no neurological deficit. Thus, in this case, lumbar disc herniation may have been a cause of spontaneous intracranial hypotension. PMID:20157378

  8. The negative chronotropic effect during lumbar spine surgery

    PubMed Central

    Chowdhury, Tumul; Schaller, Bernhard

    2017-01-01

    Abstract Background: Hemodynamic perturbations in spine surgeries are predominantly reported in cervical and thoracic level procedures. The literature related to negative cardiovascular changes (decrease of heart rate and blood pressure) in lumbar spine procedures is still scarce and only highlighted in few case reports/letters until now. Methods: With the help of a systematic literature review with predefined criteria, we, therefore, examined and synthesized here the probable underlying common cause of these hemodynamic disturbances in lumbar spine surgeries. Data aggregation to a model was done by a case survey method and established by a cause–effect relationship. Results: There are only 5 cases that met our strict predefined criteria and that were aggregated to an emergent model of an autonomous reflex arc. Conclusion: This review and consecutive data aggregation provides, for the first time, a concept of spinal cardiac reflex in lumbar spine surgeries. PMID:28072687

  9. Formation of lunar basin rings

    USGS Publications Warehouse

    Hodges, C.A.; Wilhelms, D.E.

    1978-01-01

    The origin of the multiple concentric rings that characterize lunar impact basins, and the probable depth and diameter of the transient crater have been widely debated. As an alternative to prevailing "megaterrace" hypotheses, we propose that the outer scarps or mountain rings that delineate the topographic rims of basins-the Cordilleran at Orientale, the Apennine at Imbrium, and the Altai at Nectaris-define the transient cavities, enlarged relatively little by slumping, and thus are analogous to the rim crests of craters like Copernicus; inner rings are uplifted rims of craters nested within the transient cavity. The magnitude of slumping that occurs on all scarps is insufficient to produce major inner rings from the outer. These conclusions are based largely on the observed gradational sequence in lunar central uplifts:. from simple peaks through somewhat annular clusters of peaks, peak and ring combinations and double ring basins, culminating in multiring structures that may also include peaks. In contrast, belts of slump terraces are not gradational with inner rings. Terrestrial analogs suggest two possible mechanisms for producing rings. In some cases, peaks may expand into rings as material is ejected from their cores, as apparently occurred at Gosses Bluff, Australia. A second process, differential excavation of lithologically diverse layers, has produced nested experimental craters and is, we suspect, instrumental in the formation of terrestrial ringed impact craters. Peak expansion could produce double-ring structures in homogeneous materials, but differential excavation is probably required to produce multiring and peak-in-ring configurations in large lunar impact structures. Our interpretation of the representative lunar multiring basin Orientale is consistent with formation of three rings in three layers detected seismically in part of the Moon-the Cordillera (basin-bounding) ring in the upper crust, the composite Montes Rook ring in the underlying

  10. Fingering inside the coffee ring

    NASA Astrophysics Data System (ADS)

    Weon, Byung Mook; Je, Jung Ho

    2013-01-01

    Colloidal droplets including micro- and nanoparticles generally leave a ringlike stain, called the “coffee ring,” after evaporation. We show that fingering emerges during evaporation inside the coffee ring, resulting from a bidispersed colloidal mixture of micro- and nanoparticles. Microscopic observations suggest that finger formation is driven by competition between the coffee-ring and Marangoni effects, especially when the inward Marangoni flow is overwhelmed by the outward coffee-ring flow. This finding could help to understand the variety of the final deposition patterns of colloidal droplets.

  11. Split ring containment attachment device

    DOEpatents

    Sammel, Alfred G.

    1996-01-01

    A containment attachment device 10 for operatively connecting a glovebag 200 to plastic sheeting 100 covering hazardous material. The device 10 includes an inner split ring member 20 connected on one end 22 to a middle ring member 30 wherein the free end 21 of the split ring member 20 is inserted through a slit 101 in the plastic sheeting 100 to captively engage a generally circular portion of the plastic sheeting 100. A collar potion 41 having an outer ring portion 42 is provided with fastening means 51 for securing the device 10 together wherein the glovebag 200 is operatively connected to the collar portion 41.

  12. Ground Movement in SSRL Ring

    SciTech Connect

    Sunikumar, Nikita; /UCLA /SLAC

    2011-08-25

    Users of the Stanford Synchrotron Radiation Lightsource (SSRL) are being affected by diurnal motion of the synchrotron's storage ring, which undergoes structural changes due to outdoor temperature fluctuations. In order to minimize the effects of diurnal temperature fluctuations, especially on the vertical motion of the ring floor, scientists at SSRL tried three approaches: painting the storage ring white, covering the asphalt in the middle of the ring with highly reflective Mylar and installing Mylar on a portion of the ring roof and walls. Vertical motion in the storage ring is measured by a Hydrostatic Leveling System (HLS), which calculates the relative height of water in a pipe that extends around the ring. The 24-hr amplitude of the floor motion was determined using spectral analysis of HLS data, and the ratio of this amplitude before and after each experiment was used to quantitatively determine the efficacy of each approach. The results of this analysis showed that the Mylar did not have any significant effect on floor motion, although the whitewash project did yield a reduction in overall HLS variation of 15 percent. However, further analysis showed that the reduction can largely be attributed to a few local changes rather than an overall reduction in floor motion around the ring. Future work will consist of identifying and selectively insulating these local regions in order to find the driving force behind diurnal floor motion in the storage ring.

  13. Saturn's Rings Edge-on

    NASA Technical Reports Server (NTRS)

    1995-01-01

    In one of nature's most dramatic examples of 'now-you see-them, now-you-don't', NASA's Hubble Space Telescope captured Saturn on May 22, 1995 as the planet's magnificent ring system turned edge-on. This ring-plane crossing occurs approximately every 15 years when the Earth passes through Saturn's ring plane.

    For comparison, the top picture was taken by Hubble on December 1, 1994 and shows the rings in a more familiar configuration for Earth observers.

    The bottom picture was taken shortly before the ring plane crossing. The rings do not disappear completely because the edge of the rings reflects sunlight. The dark band across the middle of Saturn is the shadow of the rings cast on the planet (the Sun is almost 3 degrees above the ring plane.) The bright stripe directly above the ring shadow is caused by sunlight reflected off the rings onto Saturn's atmosphere. Two of Saturn's icy moons are visible as tiny starlike objects in or near the ring plane. They are, from left to right, Tethys (slightly above the ring plane) and Dione.

    This observation will be used to determine the time of ring-plane crossing and the thickness of the main rings and to search for as yet undiscovered satellites. Knowledge of the exact time of ring-plane crossing will lead to an improved determination of the rate at which Saturn 'wobbles' about its axis (polar precession).

    Both pictures were taken with Hubble's Wide Field Planetary Camera 2. The top image was taken in visible light. Saturn's disk appears different in the bottom image because a narrowband filter (which only lets through light that is not absorbed by methane gas in Saturn's atmosphere) was used to reduce the bright glare of the planet. Though Saturn is approximately 900 million miles away, Hubble can see details as small as 450 miles across.

    The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science

  14. Population reference range for developmental lumbar spinal canal size

    PubMed Central

    Huang, Junbin; Law, Sheung-Wai; Xiao, Fan; Leung, Jason Chi Shun; Wang, Defeng; Shi, Lin

    2016-01-01

    Background Considerable variability exists in normal developmental lumbar spinal canal size. This impacts the likelihood of neural compromise. Spinal canal development is complete by 17 years. As diseases incurred thereafter do not knowingly affect the developmental size of the spinal canal, it is reasonable to use a selected population undergoing abdominopelvic computed tomography (CT) examination to determine developmental lumbar spinal canal size. Methods Study approval was granted by the Clinical Research Ethics Committee. Between Feb 2014 and Jan 2015, mid-vertebral spinal canal cross-sectional area (CSA), depth, width, and vertebral body CSA at each level from L1–L5 was measured, using a semi-automated computerized method in 1,080 ambulatory patients (540 males, 540 females, mean age, 50.5±17 years). Patient height and weight was measured. Results A reference range for developmental lumbar spinal canal dimensions was developed at each lumbar level for each sex. There was a 34% variation in spinal canal CSA between smallest and largest quartiles. Developmental spinal canal CSA and depth were consistently smallest at L3, enlarging cranially and caudally. Taller people had slightly larger lumbar spinal canals (P<0.0001). Males had larger spinal canal CSAs than females though relative to vertebral body CSA, spinal canal CSA was larger in females. There was no change in spinal canal CSA with age, weight or BMI (P<0.05). Conclusions A population reference range for developmental lumbar spinal canal size was developed. This allows one to objectively determine the degree of developmental spinal canal stenosis present on an individual patient basis. PMID:28090445

  15. Percutaneous endoscopic lumbar discectomy: Results of first 100 cases

    PubMed Central

    Mahesha, Kanthila

    2017-01-01

    Background: Lumbar disc herniation is a major cause of back pain and sciatica. The surgical management of lumbar disc prolapse has evolved from exploratory laminectomy to percutaneous endoscopic discectomy. Percutaneous endoscopic discectomy is the least invasive procedure for lumbar disc prolapse. The aim of this study was to analyze the clinical outcome, quality of life, neurologic function, and complications. Materials and Methods: One hundred patients with lumbar disc prolapse who were treated with percutaneous endoscopic discectomy from May 2012 to January 2014 were included in this retrospective study. Clinical followup was done at 1 month, 3 months, 6 months, 1 year, and at yearly interval thereafter. The outcome was assessed using modified Macnab's criteria, visual analog scale, and Oswestry Disability Index. Results: The mean followup period was 2 years (range 18 months - 3 years). Transforaminal approach was used in 84 patients, interlaminar approach in seven patients, and combined approach in nine patients. An excellent outcome was noted in ninety patients, good outcome in six patients, fair result in two patients, and poor result in two patients. Minor complications were seen in three patients, and two patients had recurrent disc prolapse. Mean hospital stay was 1.6 days. Conclusions: Percutaneous endoscopic lumbar discectomy is a safe and effective procedure in lumbar disc prolapse. It has the advantage that it can be performed on a day care basis under local anesthesia with shorter length of hospitalization and early return to work thus improving the quality of life earlier. The low complication rate makes it the future of disc surgery. Transforaminal approach alone is sufficient in majority of cases, although 16% of cases required either percutaneous interlaminar approach or combined approach. The procedure definitely has a learning curve, but it is acceptable with adequate preparations. PMID:28216749

  16. Spinal Anesthesia in Elderly Patients Undergoing Lumbar Spine Surgery.

    PubMed

    Lessing, Noah L; Edwards, Charles C; Brown, Charles H; Ledford, Emily C; Dean, Clayton L; Lin, Charles; Edwards, Charles C

    2017-03-01

    Spinal anesthesia is increasingly viewed as a reasonable alternative to general anesthesia for lumbar spine surgery. However, the results of spinal anesthesia in elderly patients undergoing lumbar spine decompression and combined decompression and fusion procedures are limited in the literature. The aim of this study was to report a single institution's experience using spinal anesthesia in elderly patients undergoing lumbar spine surgery. A retrospective review was conducted using a prospectively collected database of consecutive lumbar spine surgeries performed under spinal anesthesia in patients 70 years or older at a single center between December 2013 and October 2015. A total of 56 patients were included in the study; 27 patients (48%) underwent lumbar decompression and 29 patients (52%) underwent combined decompression and fusion procedures. Mean operative time was 101 minutes (range, 30-210 minutes), and mean operative blood loss was 187 mL (range, 20-700 mL). Mean maximum inpatient postoperative visual analog scale score was 6.2 (range, 1-10). Nausea occurred in 21% (12 of 56) of the patients. Mean length of stay was 2.4 days (range, 1-6 days). No mortality, stroke, permanent loss of function, or pulmonary embolism occurred. None of the cases required conversion to general anesthesia. All of the patients were ambulatory on either the day of the surgery or the next morning. These results demonstrate that spinal anesthesia is a viable method of anesthesia for patients 70 years and older undergoing lumbar spine surgery. They also demonstrate the safety of this method for patients older than 84 years and for surgeries lasting up to 3½ hours. [Orthopedics. 2017; 40(2):e317-e322.].

  17. The association of spinal osteoarthritis with lumbar lordosis

    PubMed Central

    2010-01-01

    Background Careful review of published evidence has led to the postulate that the degree of lumbar lordosis may possibly influence the development and progression of spinal osteoarthritis, just as misalignment does in other joints. Spinal degeneration can ensue from the asymmetrical distribution of loads. The resultant lesions lead to a domino- like breakdown of the normal morphology, degenerative instability and deviation from the correct configuration. The aim of this study is to investigate whether a relationship exists between the sagittal alignment of the lumbar spine, as it is expressed by lordosis, and the presence of radiographic osteoarthritis. Methods 112 female subjects, aged 40-72 years, were examined in the Outpatients Department of the Orthopedics' Clinic, University Hospital of Heraklion, Crete. Lumbar radiographs were examined on two separate occasions, independently, by two of the authors for the presence of osteoarthritis. Lordosis was measured from the top of L1 to the bottom of L5 as well as from the top of L1 to the top of S1. Furthermore, the angle between the bottom of L5 to the top of S1was also measured. Results and discussion 49 women were diagnosed with radiographic osteoarthritis of the lumbar spine, while 63 women had no evidence of osteoarthritis and served as controls. The two groups were matched for age and body build, as it is expressed by BMI. No statistically significant differences were found in the lordotic angles between the two groups Conclusions There is no difference in lordosis between those affected with lumbar spine osteoarthritis and those who are disease free. It appears that osteoarthritis is not associated with the degree of lumbar lordosis. PMID:20044932

  18. Range of Motion of the Intact Lumbar Segment: A Multivariate Study of 42 Lumbar Spines

    PubMed Central

    Cook, Daniel J.; Yeager, Matthew S.

    2015-01-01

    Background A thorough understanding of the biomechanical characteristics of the healthy human spine is critical in furthering the treatment of spinal pathology. The goal of this study was to investigate the motion of the intact lumbar spine segment as measured by range of motion (ROM), and to investigate the dependencies thereof on gender and intervertebral level. Materials and Methods Kinematic data was obtained for 42 human lumbar segments (L1-S1) in response to a pure-moment loading protocol in flexion extension (FE), lateral bending (LB) and axial torsion (AT). Data was obtained for 204 individual functional spinal units (91 female, 113 male). Multivariate analysis of variance was conducted to detect differences between genders and intervertebral levels in each mode of loading. Correlations between ROM and donor demographics, including height, weight, and age, were conducted. Results ROM was significantly greater for females than for males in FE, LB and AT (p<0.001). ROM tended to increase down the vertebral column in FE. L3-4 FE ROM was significantly greater than L1-2 (p=0.024), and L4-5 and L5-S1 FE ROM were significantly greater than for every other level (p<0.003). LB ROM tended to be greater toward the center of the segment with L2-3, L3-4 and L4-5 ROM being significantly greater than both L1-2 (p<0.001) and L5-S1 (p=0.006, p<0.001, p=0.043, respectively). A similar trend was found for AT, however only L1-2 was significantly less than all other levels (p=0.042, p<0.001, p<0.001, and p=0.034 for L2-3, L3-4, L4-5, and L5-S1 respectively). Conclusion The significant differences in lumbar ROM between male and female spine segments and between the intervertebral levels must be taken into account in study design in order to prevent biases in outcomes. The significant differences in ROM between levels may also have critical implications in the design of spinal implants, particularly those designed to maintain or restore healthy motion. PMID:25785241

  19. Lumbo-costo-vertebral syndrome with congenital lumbar hernia.

    PubMed

    Gupta, Lucky; Mala, Tariq Ahmed; Gupta, Rahul; Malla, Shahid Amin

    2014-01-01

    Lumbo-costo-vertebral syndrome (LCVS) is a set of rare abnormalities involving vertebral bodies, ribs, and abdominal wall. We present a case of LCVS in a 2-year-old girl who had a progressive swelling over left lumbar area noted for the last 12 months. Clinical examination revealed a reducible swelling with positive cough impulse. Ultrasonography showed a defect containing bowel loops in the left lumbar region. Chest x-ray showed scoliosis and hemivertebrae with absent lower ribs on left side. Meshplasty was done.

  20. Lumbar adhesive arachnoiditis following attempted epidural anesthesia--case report.

    PubMed

    Haisa, T; Todo, T; Mitsui, I; Kondo, T

    1995-02-01

    A 30-year-old female experienced a sudden sharp pain radiating down to the left leg from the lower back at epidural intubation for anesthesia at childbirth. She continued to complain of pain in the left leg afterwards. Magnetic resonance images demonstrated a conglomeration of adherent nerve roots due to lumbar adhesive arachnoiditis. Microsurgical dissection of adherent nerve roots was performed. Her symptoms disappeared after surgery, but soon recurred, being less severe and responsive to anti-inflammatory agents. Lumbar adhesive arachnoiditis should be considered for differential diagnosis in patients presenting with back and leg pain syndrome.

  1. Black ring deconstruction

    SciTech Connect

    Gimon, Eric; Gimon, Eric G.; Levi, Thomas S.

    2007-06-22

    We present a sample microstate for a black ring in four and five dimensional language. The microstate consists of a black string microstate with an additional D6-brane. We show that with an appropriate choice of parameters the piece involving the black string microstate falls down a long AdS throat, whose M-theory lift is AdS_3 x S2. We wrap a spinning dipole M2-brane on the S2 in the probe approximation. In IIA, this corresponds to a dielectric D2-brane carrying only D0-charge. We conjecture this is the firstapproximation to a cloud of D0-branes blowing up due to their non-abelian degrees of freedom and the Myers effect.

  2. Ring around the colloid

    NASA Astrophysics Data System (ADS)

    Cavallaro, Marcello, Jr.; Gharbi, Mohamed A.; Beller, Daniel A.; Čopar, Simon; Shi, Zheng; Kamien, Randall D.; Yang, Shu; Baumgart, Tobias; Stebe, Kathleen J.

    In this work, we show that Janus washers, genus-one colloids with hybrid anchoring conditions, form topologically required defects in nematic liquid crystals. Experiments under crossed polarizers reveal the defect structure to be a rigid disclination loop confined within the colloid, with an accompanying defect in the liquid crystal. When confined to a homeotropic cell, the resulting colloid-defect ring pair tilts relative to the far field director, in contrast to the behavior of toroidal colloids with purely homeotropic anchoring. We show that this tilting behavior can be reversibly suppressed by the introduction of a spherical colloid into the center of the toroid, creating a new kind of multi-shape colloidal assemblage.

  3. Lumbar corpectomy for correction of degenerative scoliosis from osteoradionecrosis reveals a delayed complication of lumbar myxopapillary ependymoma.

    PubMed

    Palejwala, Sheri K; Lawson, Kevin A; Kent, Sean L; Martirosyan, Nikolay L; Dumont, Travis M

    2016-08-01

    Osteoradionecrosis is a known complication following radiation therapy, presenting most commonly in the cervical spine as a delayed consequence of radiation that is often necessary in the management of head and neck cancers. In contrast, osteoradionecrosis has rarely been described in the lumbar spine. Here we describe, to our knowledge, the first reported case of lumbar spine osteoradionecrosis, after adjuvant radiation for a primary spinal cord tumor, leading to progressive degenerative scoliosis which required subsequent operative management. Established guidelines recommend that mature bone can tolerate a dose of up to 6000 cGy without injury. However, once bone has been exposed to radiation over this level progressive soft tissue changes may lead to devascularization, leaving the bone vulnerable to osteonecrosis, specifically when manipulated. Radiation necrosis can be progressive and lead to eventual mechanical instability requiring debridement and surgical fixation. In the setting of the lumbar spine, osseous necrosis can lead to biomechanical instability, deformity, pain, and neurologic deficit.

  4. Development of a fibre optic goniometer system to measure lumbar and hip movement to detect activities and their lumbar postures.

    PubMed

    Bell, J A; Stigant, M

    2007-01-01

    If sitting postures influence the risk of developing low back pain then it is important that quantification of sedentary work activities and simultaneous measurement of lumbar postural characteristics takes place. The objective of this study was to develop a system for identifying activities and their associated lumbar postures using fibre optic goniometers (FOGs). Five student subjects wore two FOGs attached to the lumbar spine and hip for 8 min while being recorded using a video camera when sitting, standing and walking. Observer Software was used to code the video recording, enabling the sagittal movement characteristics of each FOG to be described for individual activities. Results indicated that each activity produced unique data, and could be independently identified from their motion profiles by three raters (k = 1). The data will be used to develop algorithms to automate the process of activity detection. This system has the potential to measure behaviour in non-clinical settings.

  5. The Saturn Ring Observer: In situ studies of planetary rings

    NASA Astrophysics Data System (ADS)

    Nicholson, P. D.; Tiscareno, M. S.; Spilker, L. J.

    2010-12-01

    As part of the Planetary Science Decadal Survey recently undertaken by the NRC's Space Studies Board for the National Academy of Sciences, studies were commissioned for a number of potential missions to outer planet targets. One of these studies examined the technological feasibility of a mission to carry out in situ studies of Saturn's rings, from a spacecraft placed in a circular orbit above the ring plane: the Saturn Ring Observer. The technical findings and background are discussed in a companion poster by T. R. Spilker et al. Here we outline the science goals of such a mission. Most of the fundamental interactions in planetary rings occur on spatial scales that are unresolved by flyby or orbiter spacecraft. Typical particle sizes in the rings of Saturn are in the 1 cm - 10 m range, and average interparticle spacings are a few meters. Indirect evidence indicates that the vertical thickness of the rings is as little as 5 - 10 m, which implies a velocity dispersion of only a few mm/sec. Theories of ring structure and evolution depend on the unknown characteristics of interparticle collisions and on the size distribution of the ring particles. The SRO could provide direct measurements of both the coefficient of restitution -- by monitoring individual collisions -- and the particles’ velocity dispersion. High-resolution observations of individual ring particles should also permit estimates of their spin states. Numerical simulations of Saturn’s rings incorporating both collisions and self-gravity predict that the ring particles are not uniformly distributed, but are instead clustered into elongated structures referred to as “self-gravity wakes”, which are continually created and destroyed on an orbital timescale. Theory indicates that the average separation between wakes in the A ring is of order 30-100 m. Direct imaging of self-gravity wakes, including their formation and subsequent dissolution, would provide critical validation of these models. Other

  6. Effect of steerable cage placement during minimally invasive transforaminal lumbar interbody fusion on lumbar lordosis.

    PubMed

    Lindley, Timothy E; Viljoen, Stephanus V; Dahdaleh, Nader S

    2014-03-01

    Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is commonly used for the treatment of a variety of degenerative spine disorders. Recently, steerable interbody cages have been developed which potentially allow for greater restoration of lumbar lordosis. Here we describe a technique and radiographic results following minimally invasive placement of steerable cages through a bilateral approach. A retrospective review was conducted of the charts and radiographs of 15 consecutive patients who underwent 19 levels of bilateral MIS-TLIF with the placement of steerable cages. These were compared to 10 patients who underwent 16 levels of unilateral MIS-TLIF with the placement of bullet cages. The average age, body mass index, distribution of the levels operated and follow-up were similar in both groups. The average height of the steerable cage placed was 10.9 mm compared to 8.5mm for bullet cages. The preoperative focal Cobb's angle per level was similar between both groups with a mean of -5.3 degrees for the steerable cage group and -4.8 degrees for the bullet cage group. There was a significant improvement in postoperative Cobb's angle after placement of a steerable cage with a mean of -13.7 (p<0.01) and this persisted at the last follow-up with -13 degrees (p<0.01). There was no significant change in Cobb's angle after bullet cage placement with -5.7 degrees postoperatively and a return to the baseline preoperative Cobb's angle of -4.8 at the last follow-up. Steerable cage placement for MIS-TLIF improves focal lordosis compared to bullet cage placement.

  7. Fibre ring cavity semiconductor laser

    SciTech Connect

    Duraev, V P; Medvedev, S V

    2013-10-31

    This paper presents a study of semiconductor lasers having a polarisation maintaining fibre ring cavity. We examine the operating principle and report main characteristics of a semiconductor ring laser, in particular in single- and multiple-frequency regimes, and discuss its application areas. (lasers)

  8. Contraceptive vaginal rings: a review.

    PubMed

    Brache, Vivian; Faundes, Anibal

    2010-11-01

    Development efforts on contraceptive vaginal rings were initiated over 40 years ago based on two principles: the capacity of the vaginal epithelium to absorb steroids and the capacity of elastomers to release these hormones at a nearly constant rate. Numerous models of contraceptive vaginal rings (CVRs) have been studied, but only two have reached the market: NuvaRing, a combined ring that releases etonogestrel (ENG) and ethinylestradiol (EE), and Progering, a progesterone-releasing ring for use in lactating women. The main advantages of CVRs are their effectiveness (similar to or slightly better than the pill), ease of use without the need of remembering a daily routine, user's ability to control initiation and discontinuation, nearly constant release rate allowing for lower doses, greater bioavailability and good cycle control with the combined ring. The main disadvantages are related to the mode of delivery; CVRs may cause vaginal discharge and complaints, ring expulsion is not uncommon, the ring may be felt during coitus and vaginal insertion may be unpleasant for some women. The studies reviewed in this article provide evidence that CVRs are safe, effective and highly acceptable to women. There is no doubt that CVRs offer a new, effective contraceptive option to women, expanding their available choices of hormonal contraception.

  9. Ring Infiltrate in Staphylococcal Keratitis

    PubMed Central

    Wallang, Batriti S.; Sharma, Savitri; Sahu, Srikant K.; Mittal, Ruchi

    2013-01-01

    Smear and culture tests of corneal scrapings from a patient with a ring infiltrate confirmed significant growth of a Staphylococcus species resistant to fluoroquinolones. Because of nonresponse to medical management, the patient underwent therapeutic penetrating keratoplasty. Staphylococcal infection of the cornea may appear as a ring-like infiltrate that is recalcitrant to medical management. PMID:23100354

  10. Biomechanics of Corneal Ring Implants

    PubMed Central

    2015-01-01

    Purpose: To evaluate the biomechanics of corneal ring implants by providing a related mathematical theory and biomechanical model for the treatment of myopia and keratoconus. Methods: The spherical dome model considers the inhomogeneity of the tunica of the eye, dimensions of the cornea, lamellar structure of the corneal stroma, and asphericity of the cornea. It is used in this study for calculating a strengthening factor sf for the characterization of different ring-shaped corneal implant designs. The strengthening factor is a measure of the amount of strengthening of the cornea induced by the implant. Results: For ring segments and incomplete rings, sf = 1.0, which indicates that these implants are not able to strengthen the cornea. The intracorneal continuous complete ring (MyoRing) has a strengthening factor of up to sf = 3.2. The MyoRing is, therefore, able to strengthen the cornea significantly. Conclusions: The result of the presented biomechanical analysis of different ring-shaped corneal implant designs can explain the different postoperative clinical results of different implant types in myopia and keratoconus. PMID:26312619

  11. Reversible Seeding in Storage Rings

    SciTech Connect

    Ratner, Daniel; Chao, Alex; /SLAC

    2011-12-14

    We propose to generate steady-state microbunching in a storage ring with a reversible seeding scheme. High gain harmonic generation (HGHG) and echo-enabled harmonic generation (EEHG) are two promising methods for microbunching linac electron beams. Because both schemes increase the energy spread of the seeded beam, they cannot drive a coherent radiator turn-by-turn in a storage ring. However, reversing the seeding process following the radiator minimizes the impact on the electron beam and may allow coherent radiation at or near the storage ring repetition rate. In this paper we describe the general idea and outline a proof-of-principle experiment. Electron storage rings can drive high average power light sources, and free-electron lasers (FELs) are now producing coherent light sources of unprecedented peak brightness While there is active research towards high repetition rate FELs (for example, using energy recovery linacs), at present there are still no convenient accelerator-based sources of high repetition rate, coherent radiation. As an alternative avenue, we recently proposed to establish steady-state microbunching (SSMB) in a storage ring. By maintaining steady-state coherent microbunching at one point in the storage ring, the beam generates coherent radiation at or close to the repetition rate of the storage ring. In this paper, we propose a method of generating a microbunched beam in a storage ring by using reversible versions of linac seeding schemes.

  12. How Jupiter's Ring Was Discovered.

    ERIC Educational Resources Information Center

    Elliot, James; Kerr, Richard

    1985-01-01

    "Rings" (by astronomer James Elliot and science writer Richard Kerr) is a nontechnical book about the discovery and exploration of ring systems from the time of Galileo to the era of the Voyager spacecraft. One of this book's chapters is presented. (JN)

  13. Rings Full of Waves (zoom)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This image shows a close-up view of a density wave in Saturn's A ring. It was taken by the narrow angle camera on the Cassini spacecraft after successful entry into Saturn's orbit. The view shows the dark, or unlit, side of the rings.

  14. Simulating the Smallest Ring World of Chariklo

    NASA Astrophysics Data System (ADS)

    Michikoshi, Shugo; Kokubo, Eiichiro

    2017-03-01

    A ring system consisting of two dense narrow rings has been discovered around Centaur Chariklo. The existence of these rings around a small object poses various questions about their origin, stability, and lifetime. In order to understand the nature of Chariklo’s rings, we perform global N-body simulations of the self-gravitating collisional particle rings for the first time. We find that Chariklo should be denser than the ring material in order to avoid the rapid diffusion of the rings. If Chariklo is denser than the ring material, fine spiral structures called self-gravity wakes occur in the inner ring. These wakes accelerate the viscous spreading of the ring significantly and typically occur on timescales of about 100 {years} for m-sized ring particles, which is considerably shorter than the timescales suggested in previous studies. The existence of these narrow rings implies smaller ring particles or the existence of shepherding satellites.

  15. 49 CFR 572.85 - Lumbar spine flexure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... rotate from its initial position in accordance with Figure No. 18 of § 572.21 (49 CFR part 572) by 40... removal of the force to within 5 degrees of its initial position. (b) Test procedure. (1) The lumbar spine... 13 and 59 through 63), removed. (2) With the torso assembled in an upright position, adjust...

  16. 49 CFR 572.43 - Lumbar spine and pelvis.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... buttocks are tangent to a transverse vertical plane. (5) Impact the pelvis with the test probe so that at... 49 Transportation 7 2010-10-01 2010-10-01 false Lumbar spine and pelvis. 572.43 Section 572.43... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Side Impact Dummy...

  17. Lumbar facet stress fracture in a ballet dancer.

    PubMed

    Fehlandt, A F; Micheli, L J

    1993-12-01

    A frequent cause of back pain in athletes and dancers is stress injury to the posterior vertebral elements. Stress fractures affect the pars interarticularis and, rarely, other vertebral regions. The authors present their experience with the diagnosis and treatment of a fourth lumbar inferior articular facet stress fracture in a ballerina in this brief report and discuss the literature concerning posterior element stress fractures.

  18. [Major vascular complications following surgery for a herniated lumbar disk].

    PubMed

    Abad, C; Martel, D; Feijóo, J J; Carreira, L

    1993-01-01

    Two cases of arterial injury of the iliac arteries during surgery of the lumbar disc are presented. Both patients were successfully operated, in the first case a primary repair was accomplished, the second patient was treated by means of an ileo-femoral bypass graft. A comment of the pathophysiology, diagnostic and surgical management of this unusual complication is presented.

  19. Effects of vision and lumbar posture on trunk neuromuscular control.

    PubMed

    Maaswinkel, Erwin; van Drunen, Paul; Veeger, Dirk-Jan H E J; van Dieën, Jaap H

    2015-01-21

    The goal of this study was to determine the effects of vision and lumbar posture on trunk neuromuscular control. Torso perturbations were applied with a pushing device while the subjects were restrained at the pelvis in a kneeling-seated position. Torso kinematics and the muscle activity of the lumbar part of the M. Longissimus were recorded for 14 healthy subjects. Four conditions were included: a flexion, extension and neutral lumbar posture with eyes closed and the neutral posture with eyes open. Frequency response functions of the admittance and reflexes showed that there was no significant difference between the eyes open and eyes closed conditions, thereby confirming that vision does not play a role in the stabilization of the trunk during small-amplitude trunk perturbations. In contrast, manipulating posture did lead to significant differences. In particular, the flexed condition led to a lower admittance and lower reflex contribution compared to the neutral condition. Furthermore, the muscle pre-activation (prior to the onset of the perturbation) was significantly lower in the flexed posture compared to neutral. This confirms that flexing the lumbar spine increases the passive tissue stiffness and decreases the contribution of reflex activity to trunk control.

  20. Radiologic features of lumbar spine in ochronosis in late stages.

    PubMed

    Bayindir, Petek; Yilmaz Ovali, Gülgün; Pabuşçu, Yüksel; Temiz, Cüneyt; Duruoz, Tuncay

    2006-07-01

    Ochronosis is a rare hereditary disorder of tyrosine metabolism. Severe degenerative arthritis and spondylosis occur in the later stages of this disease. Radiologic examinations may reveal changes considered almost pathognomonic for ochronosis. We present the radiologic features of the lumbar spine in two ochronotic patients who were diagnosed after radiologic examinations in the late stages of the disease.

  1. How to interpret computed tomography of the lumbar spine

    PubMed Central

    Mobasheri, R; Das, T; Vaidya, S; Mallik, S; El-Hussainy, M; Casey, A

    2014-01-01

    Computed tomography (CT) of the spine has remained an important tool in the investigation of spinal pathology. This article helps to explain the basics of CT of the lumbar spine to allow the clinician better use of this diagnostic tool. PMID:25245727

  2. Roseomonas spinal epidural abscess complicating instrumented posterior lumbar interbody fusion.

    PubMed

    Maraki, Sofia; Bantouna, Vasiliki; Lianoudakis, Efstratios; Stavrakakis, Ioannis; Scoulica, Efstathia

    2013-07-01

    The first case of a spinal epidural abscess caused by Roseomonas mucosa following instrumented posterior lumbar fusion is presented. Although rare, because of its highly resistant profile, Roseomonas species should be included in the differential diagnosis of epidural abscesses in both immunocompromised and immunocompetent hosts.

  3. Lumbar Herniation of Kidney following Iliac Crest Bone Harvest

    PubMed Central

    2016-01-01

    The iliac crest is a popular source for autogenous bone harvesting, but the process is rife with complications. This case report presents a patient that experienced incisional lumbar herniation of her kidney following an iliac crest bone harvesting procedure. A discussion is included on the underappreciated complications of this procedure and recommendations for improving outcomes with more thorough evaluation and documentation. PMID:28042490

  4. 49 CFR 572.115 - Lumbar spine and pelvis.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 7 2011-10-01 2011-10-01 false Lumbar spine and pelvis. 572.115 Section 572.115 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Side Impact Hybrid...

  5. 49 CFR 572.115 - Lumbar spine and pelvis.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 7 2013-10-01 2013-10-01 false Lumbar spine and pelvis. 572.115 Section 572.115 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Side Impact Hybrid...

  6. 49 CFR 572.115 - Lumbar spine and pelvis.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 7 2014-10-01 2014-10-01 false Lumbar spine and pelvis. 572.115 Section 572.115 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Side Impact Hybrid...

  7. 49 CFR 572.115 - Lumbar spine and pelvis.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 7 2012-10-01 2012-10-01 false Lumbar spine and pelvis. 572.115 Section 572.115 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Side Impact Hybrid...

  8. Endoscopic foraminotomy for recurrent lumbar radiculopathy after TLIF: Technical report

    PubMed Central

    Telfeian, Albert E.

    2015-01-01

    Background: Transforaminal lumbar interbody fusion (TLIF) is a well-accepted fusion technique that uses unilateral facet removal as an oblique corridor for inserting an interbody spacer. This manuscript focused on five cases of endoscopic foraminotomy for patients presenting with recurrent radiculopathy after TLIF procedures. Methods: After Institutional Review Board approval, charts from five patients with lumbar radiculopathy and instrumented TLIF procedures who underwent subsequent endoscopic procedures between 2011 and 2013 were reviewed. Results: The average pain relief 1 year postoperatively was reported to be 63.8%, good results as defined by MacNab. The average preoperative visual analog scale (VAS) score was 9.5, indicated in our questionnaire as severe and constant pain. The average 1 year postoperative VAS score was 3.5, indicated in our questionnaire as mild and intermittent pain. Conclusion: Transforaminal endoscopic discectomy and foraminotomy could be used as a safe, yet, minimally invasive and innovative technique for the treatment of lumbar radiculopathy in the setting of previous instrumented lumbar fusion. IRB approval: Lifespan: IRB Study # 600415 PMID:25949850

  9. 49 CFR 572.9 - Lumbar spine, abdomen, and pelvis.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...″ cap screw holes and attach the front mounting at the femur axial rotation joint. Tighten the mountings so that the pelvic-lumbar adapter is horizontal and adjust the femur friction plungers at each hip socket joint to 240 inch-pounds torque. (3) Flex the thorax forward 50° and then rearward as necessary...

  10. 49 CFR 572.9 - Lumbar spine, abdomen, and pelvis.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...″ cap screw holes and attach the front mounting at the femur axial rotation joint. Tighten the mountings so that the pelvic-lumbar adapter is horizontal and adjust the femur friction plungers at each hip socket joint to 240 inch-pounds torque. (3) Flex the thorax forward 50° and then rearward as necessary...

  11. 49 CFR 572.9 - Lumbar spine, abdomen, and pelvis.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...″ cap screw holes and attach the front mounting at the femur axial rotation joint. Tighten the mountings so that the pelvic-lumbar adapter is horizontal and adjust the femur friction plungers at each hip socket joint to 240 inch-pounds torque. (3) Flex the thorax forward 50° and then rearward as necessary...

  12. 49 CFR 572.9 - Lumbar spine, abdomen, and pelvis.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...″ cap screw holes and attach the front mounting at the femur axial rotation joint. Tighten the mountings so that the pelvic-lumbar adapter is horizontal and adjust the femur friction plungers at each hip socket joint to 240 inch-pounds torque. (3) Flex the thorax forward 50° and then rearward as necessary...

  13. 49 CFR 572.9 - Lumbar spine, abdomen, and pelvis.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...″ cap screw holes and attach the front mounting at the femur axial rotation joint. Tighten the mountings so that the pelvic-lumbar adapter is horizontal and adjust the femur friction plungers at each hip socket joint to 240 inch-pounds torque. (3) Flex the thorax forward 50° and then rearward as necessary...

  14. Ring Buffered Network Bus

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This report describes the research effort to demonstrate the integration of a data sharing technology, Ring Buffered Network Bus, in development by Dryden Flight Research Center, with an engine simulation application, the Java Gas Turbine Simulator, in development at the University of Toledo under a grant from the Glenn Research Center. The objective of this task was to examine the application of the RBNB technologies as a key component in the data sharing, health monitoring and system wide modeling elements of the NASA Aviation Safety Program (AVSP) [Golding, 1997]. System-wide monitoring and modeling of aircraft and air safety systems will require access to all data sources which are relative factors when monitoring or modeling the national airspace such as radar, weather, aircraft performance, engine performance, schedule and planning, airport configuration, flight operations, etc. The data sharing portion of the overall AVSP program is responsible for providing the hardware and software architecture to access and distribute data, including real-time flight operations data, among all of the AVSP elements. The integration of an engine code capable of numerically "flying" through recorded flight paths and weather data using a software tool that allows for distributed access of data to this engine code demonstrates initial steps toward building a system capable of monitoring and modeling the National Airspace.

  15. Lumbar Catheter Placement Using Paramedian Approach Under Fluoroscopic Guidance

    PubMed Central

    Qureshi, Adnan I.; Khan, Asif A.; Malik, Ahmed A.; Afzal, Mohammad Rauf; Herial, Nabeel A.; Qureshi, Mushtaq H.; Suri, M. Fareed K.

    2016-01-01

    Background Lumbar catheter placement under fluoroscopic guidance may reduce the rate of technical failures and associated complications seen with insertion guided by manually palpable landmarks. Methods We reviewed our experience with 43 attempted lumbar catheter placements using paramedian approach under fluoroscopic guidance and ascertained rates of technical success, and clinical events. Results Among the 43 patients, 18, 1, and 1 patients were on aspirin (with dipyrimadole in 2), clopidogrel, and combination of both, respectively. Lumbar catheter placement was successful in 42 of 43 attempted placements. Floroscopic guidance was critical in three patients; one patient had severe cerebrospinal fluid (CSF) depletion (empty thecal sac phenomenon) following pituitary surgery leading to no cerebrospinal fluid return despite correct placement confirmation under fluoroscopy. Two patients had spinal needle placement at the junction between epidural and cerebrospinal fluid spaces (junctional position) leading to cerebrospinal fluid return but inability to introduce the lumbar catheter. After confirmation of position by the injection of contrast or radiographic landmarks the needle was advanced by indenting the subcutaneous tissue or reinserting at a spinal level above the first insertion. The lumbar catheter remained in position over a mean period (±standard deviation) of 4.1(±2.3) days. Improvement in hydrocephalus was seen in two patients with intracranial mass lesions. One patient developed cerebrospinal fluid leakage through the insertion track following removal of catheter and required skin suturing at the site of insertion. Conclusions We observed a high technical success rate with low rate of complications even in patients with intracranial mass lesions, those on ongoing antiplatelet medications or in whom insertion would not be possible guided by manually palpable landmarks. PMID:26958156

  16. Posterior Lumbar Interbody Fusion via a Unilateral Approach

    PubMed Central

    Shin, Hyun Chul; Yi, Seong; Kim, Sang Hyun; Yoon, Do Heum

    2006-01-01

    This study sought to determine the outcomes of posterior lumbar interbody fusion (PLIF), via a unilateral approach, in selected patients who presented with unilateral leg pain and segmental instability of the lumbar spine. Patients with a single level of a herniated disc disease in the lumbar spine, unilateral leg pain, chronic disabling lower back pain (LBP), and a failed conservative treatment, were considered for the procedure. A total of 41 patients underwent a single-level PLIF using two PEEK™ (Poly-Ether-Ether-Ketone) cages filled with iliac bone, via a unilateral approach. The patients comprised 21 women and 20 men with a mean age of 41 years (range: 22 to 63 years). Two cages were inserted using a unilateral medial facetectomy and a partial hemilaminectomy. At follow-up, the outcomes were assessed using the Prolo Scale. The success of the fusion was determined by dynamic lumbar radiography and/or computerized tomography scanning. All the patients safely underwent surgery without severe complications. During a mean follow-up period of 26 months, 1 patient underwent percutaneous pedicle screw fixation due to persistent LBP. A posterior displacement of the cage was found in one patient. At the last follow up, 90% of the patients demonstrated satisfactory results. An osseous fusion was present in 85% of the patients. A PLIF, via a unilateral approach, enables a solid union with satisfactory clinical results. This preserves part of the posterior elements of the lumbar spine in selected patients with single level instability and unilateral leg pain. PMID:16807980

  17. Ion Rings for Magnetic Fusion

    SciTech Connect

    Greenly, John, B.

    2005-07-31

    This Final Technical Report presents the results of the program, Ion Rings for Magnetic Fusion, which was carried out under Department of Energy funding during the period August, 1993 to January, 2005. The central objective of the program was to study the properties of field-reversed configurations formed by ion rings. In order to reach this objective, our experimental program, called the Field-reversed Ion Ring Experiment, FIREX, undertook to develop an efficient, economical technology for the production of field-reversed ion rings. A field-reversed configuration (FRC) in which the azimuthal (field-reversing) current is carried by ions with gyro-radius comparable to the magnetic separatrix radius is called a field-reversed ion ring. A background plasma is required for charge neutralization of the ring, and this plasma will be confined within the ring's closed magnetic flux. Ion rings have long been of interest as the basis of compact magnetic fusion reactors, as the basis for a high-power accelerator for an inertial fusion driver, and for other applications of high power ion beams or plasmas of high energy density. Specifically, the FIREX program was intended to address the longstanding question of the contribution of large-orbit ions to the observed stability of experimental FRCs to the MHD tilt mode. Typical experimental FRCs with s {approx} 2-4, where s is the ratio of separatrix radius to ion gyro-radius, have been stable to tilting, but desired values for a fusion reactor, s > 20, should be unstable. The FIREX ring would consist of a plasma with large s for the background ions, but with s {approx} 1 for the ring ions. By varying the proportions of these two populations, the minimum proportion of large-orbit ions necessary for stability could be determined. The incorporation of large-orbit ions, perhaps by neutral-beam injection, into an FRC has been advanced for the purpose of stabilizing, heating, controlling angular momentum, and aiding the formation of a

  18. Genetics Home Reference: ring chromosome 20 syndrome

    MedlinePlus

    ... Home Health Conditions ring chromosome 20 syndrome ring chromosome 20 syndrome Enable Javascript to view the expand/ ... Download PDF Open All Close All Description Ring chromosome 20 syndrome is a condition that affects the ...

  19. Genetics Home Reference: ring chromosome 14 syndrome

    MedlinePlus

    ... Home Health Conditions ring chromosome 14 syndrome ring chromosome 14 syndrome Enable Javascript to view the expand/ ... Download PDF Open All Close All Description Ring chromosome 14 syndrome is a condition characterized by seizures ...

  20. Lateral Lumbar Interbody Fusion for Ossification of the Yellow Ligament in the Lumbar Spine: First Reported Case

    PubMed Central

    Abe, Tetsuya; Funayama, Toru; Noguchi, Hiroshi; Nakayama, Keita; Miura, Kousei; Nagashima, Katsuya; Kumagai, Hiroshi; Yamazaki, Masashi

    2017-01-01

    When ossification of the yellow ligament (OYL) occurs in the lumbar spine and extends to the lateral wall of the spinal canal, facetectomy is required to remove all of the ossified lesion and achieve decompression. Subsequent posterior fixation with interbody fusion will then be necessary to prevent postoperative progression of the ossification and intervertebral instability. The technique of lateral lumbar interbody fusion (LLIF) has recently been introduced. Using this procedure, surgeons can avoid excess blood loss from the extradural venous plexus and detachment of the ossified lesion and the ventral dura mater is avoidable. We present a 55-year-old male patient with OYL at L3/4 and anterior spondylolisthesis of L4 vertebra, with concomitant ossification of the posterior longitudinal ligament, who presented with a severe gait disturbance. He underwent a 2-stage operation without complications: LLIF for L3/4 and L4/5 was performed at the initial surgery, and posterior decompression fixation using pedicle screws from L3 to L5 was performed at the second surgery. His postoperative progress was favorable, and his interbody fusion was deemed successful. Here, we present the first reported case of LLIF for OYL of the lumbar spine. This procedure can be a good option for OYL of the lumbar spine. PMID:28352485

  1. Researches on the Piston Ring

    NASA Technical Reports Server (NTRS)

    Ehihara, Keikiti

    1944-01-01

    In internal combustion engines, steam engines, air compressors, and so forth, the piston ring plays an important role. Especially, the recent development of Diesel engines which require a high compression pressure for their working, makes, nowadays, the packing action of the piston ring far more important than ever. Though a number of papers have been published in regard to researches on the problem of the piston ring, none has yet dealt with an exact measurement of pressure exerted on the cylinder wall at any given point of the ring. The only paper that can be traced on this subject so far is Mr. Nakagawa's report on the determination of the relative distribution of pressure on the cylinder wall, but the measuring method adopted therein appears to need further consideration. No exact idea has yet been obtained as to how the obturation of gas between the piston and cylinder, the frictional resistance of the piston, and the wear of the cylinder wall are affected by the intensity and the distribution of the radial pressure of the piston ring. Consequently, the author has endeavored, by employing an apparatus of his own invention, to get an exact determination of the pressure distribution of the piston ring. By means of a newly devised ring tester, to which piezoelectricity of quartz was applied, the distribution of the radial pressure of many sample rings on the market was accurately determined. Since many famous piston rings show very irregular pressure distribution, the author investigated and achieved a manufacturing process of the piston ring which will exert uniform pressure on the cylinder wall. Temperature effects on the configuration and on the mean spring power have also been studied. Further, the tests were performed to ascertain how the gas tightness of the piston ring may be affected by the number or spring power. The researches as to the frictional resistance between the piston ring and the cylinder wall were carried out, too. The procedure of study, and

  2. Reflex ring laser amplifier system

    DOEpatents

    Summers, Mark A.

    1985-01-01

    A laser pulse is injected into an unstable ring resonator-amplifier structure. Inside this resonator the laser pulse is amplified, spatially filtered and magnified. The laser pulse is recirculated in the resonator, being amplified, filtered and magnified on each pass. The magnification is chosen so that the beam passes through the amplifier in concentric non-overlapping regions similar to a single pass MOPA. After a number of passes around the ring resonator the laser pulse is spatially large enough to exit the ring resonator system by passing around an output mirror.

  3. Change of Lumbar Ligamentum Flavum after Indirect Decompression Using Anterior Lumbar Interbody Fusion

    PubMed Central

    Orita, Sumihisa; Yamauchi, Kazuyo; Eguchi, Yawara; Aoki, Yasuchika; Nakamura, Junichi; Miyagi, Masayuki; Suzuki, Miyako; Kubota, Gou; Inage, Kazuhide; Sainoh, Takeshi; Sato, Jun; Fujimoto, Kazuki; Shiga, Yasuhiro; Abe, Koki; Kanamoto, Hiroto; Inoue, Gen; Takahashi, Kazuhisa; Furuya, Takeo; Koda, Masao

    2017-01-01

    Study Design Retrospective case series. Purpose The purpose of this study was to examine changes in the ligamentum flavum thickness and remodeling of the spinal canal after anterior fusion during a 10-year follow-up. Overview of Literature Extreme lateral interbody fusion provides minimally invasive treatment of the lumbar spine; this anterior fusion without direct posterior decompression, so-called indirect decompression, can achieve pain relief. Anterior fusion may restore disc height, stretch the flexure of the ligamentum flavum, and increase the spinal canal diameter. However, changes in the ligamentum flavum thickness and remodeling of the spinal canal after anterior fusion during a long follow-up have not yet been reported. Methods We evaluated 10 patients with L4 spondylolisthesis who underwent stand-alone anterior interbody fusion using the iliac crest bone. Magnetic resonance imaging was performed 10 years after surgery. The cross-sectional area (CSA) of the dural sac and the ligamentum flavum at L1–2 to L5–S1 was calculated using a Picture Archiving and Communication System. Results Spinal fusion with correction loss (average, 4.75 mm anterior slip) was achieved in all patients 10 years postsurgery. The average CSAs of the dural sac and the ligamentum flavum at L1–2 to L5–S1 were 150 mm2 and 78 mm2, respectively. The average CSA of the ligamentum flavum at L4–5 (30 mm2) (fusion level) was significantly less than that at L1–2 to L3–4 or L5–S1. Although patients had an average anterior slip of 4.75 mm, the average CSA of the dural sac at L4–5 was significantly larger than at the other levels. Conclusions Spinal stability induced a lumbar ligamentum flavum change and a sustained remodeling of the spinal canal, which may explain the long-term pain relief after indirect decompression fusion surgery. PMID:28243378

  4. Black rings at large D

    NASA Astrophysics Data System (ADS)

    Tanabe, Kentaro

    2016-02-01

    We study the effective theory of slowly rotating black holes at the infinite limit of the spacetime dimension D. This large D effective theory is obtained by integrating the Einstein equation with respect to the radial direction. The effective theory gives equations for non-linear dynamical deformations of a slowly rotating black hole by effective equations. The effective equations contain the slowly rotating Myers-Perry black hole, slowly boosted black string, non-uniform black string and black ring as stationary solutions. We obtain the analytic solution of the black ring by solving effective equations. Furthermore, by perturbation analysis of effective equations, we find a quasinormal mode condition of the black ring in analytic way. As a result we confirm that thin black ring is unstable against non-axisymmetric perturbations. We also include 1 /D corrections to the effective equations and discuss the effects by 1 /D corrections.

  5. Dissipative ring solitons with vorticity.

    PubMed

    Soto-Crespo, J M; Akhmediev, N; Mejia-Cortés, C; Devine, N

    2009-03-16

    We study dissipative ring solitons with vorticity in the frame of the (2+1)-dimensional cubic-quintic complex Ginzburg-Landau equation. In dissipative media, radially symmetric ring structures with any vorticity m can be stable in a finite range of parameters. Beyond the region of stability, the solitons lose the radial symmetry but may remain stable, keeping the same value of the topological charge. We have found bifurcations into solitons with n-fold bending symmetry, with n independent on m. Solitons without circular symmetry can also display (m + 1)-fold modulation behaviour. A sequence of bifurcations can transform the ring soliton into a pulsating or chaotic state which keeps the same value of the topological charge as the original ring.

  6. Ring resonant cavities for spectroscopy

    DOEpatents

    Zare, R.N.; Martin, J.; Paldus, B.A.; Xie, J.

    1999-06-15

    Ring-shaped resonant cavities for spectroscopy allow a reduction in optical feedback to the light source, and provide information on the interaction of both s- and p-polarized light with samples. A laser light source is locked to a single cavity mode. An intracavity acousto-optic modulator may be used to couple light into the cavity. The cavity geometry is particularly useful for Cavity Ring-Down Spectroscopy (CRDS). 6 figs.

  7. Analysis of Ring Wake Simulations

    NASA Astrophysics Data System (ADS)

    Lewis, M. C.; Stewart, G. R.

    1999-09-01

    indent=20pt Collisional N-body simulations at the edge of a perturbed planetary ring are used to model the edges of the Encke gap in Saturn's rings. A small satellite, Pan, orbits inside the Encke gap and excites forced eccentricities and density wakes on both edges of the gap. The simulations use a local cell method to model a narrow ring using particles of the appropriate size for the A-ring at the proper optical depth. In the simulations we see evidence for shear reversal at the wake peaks. Our results imply that the most significant factor in the damping of the wakes is the reduction of the forced eccentricity and not randomization of the phase angles of the particles. The reduction of the forced eccentricity occurs in an orderly fashion with steep drops at each successive wake maximum following the highest density wake peak. indent=20pt At the inner edge (that nearer the perturber) we see phase shifts visible as bending of the line wake maxima. Because the simulations are actually of narrow rings, we also see a number of interesting phenomena at the outer edge. A strong boundary layer forms at that edge, which becomes partially detached from the rest of the ring. The wake patterns persist much further downstream in this boundary layer than they do in the rest of the ring. We also observe that in the less dense region between the main section of the ring and the boundary layer the magnitude of the forced eccentricities reverse their behavior in the main part and increase at each wake maxima. indent=20pt At the talk we will compare our results to the various analytic theories of Borderies, Goldreich, and Tremaine.

  8. Resonance capture and Saturn's rings

    SciTech Connect

    Patterson, C.W.

    1986-05-01

    We have assigned the resonances apparently responsible for the stabilization of the Saturn's shepherd satellites and for the substructure seen in the F-ring and the ringlets in the C-ring. We show that Saturn's narrow ringlets have a substructure determined by three-body resonances with Saturn's ringmoons and the sun. We believe such resonances have important implications to satellite formation. 17 refs., 1 fig., 1 tab.

  9. Ring resonant cavities for spectroscopy

    DOEpatents

    Zare, Richard N.; Martin, Juergen; Paldus, Barbara A.; Xie, Jinchun

    1999-01-01

    Ring-shaped resonant cavities for spectroscopy allow a reduction in optical feedback to the light source, and provide information on the interaction of both s- and p-polarized light with samples. A laser light source is locked to a single cavity mode. An intracavity acousto-optic modulator may be used to couple light into the cavity. The cavity geometry is particularly useful for Cavity Ring-Down Spectroscopy (CRDS).

  10. Classifying Saturn's F Ring Strands

    NASA Astrophysics Data System (ADS)

    Albers, Nicole; Sremcevic, M.; Esposito, L. W.; Colwell, J. E.

    2009-09-01

    The Cassini Ultraviolet Imaging Spectrograph (UVIS) High Speed Photometer (HSP) has recorded more than 113 stellar occultations by Saturn's F ring providing measurements with ring plane resolutions of a few dozen meters and better. Inner and outer F ring strands have been seen throughout the Cassini mission where they revealed themselves as non-continuous, azimuthally and temporally highly variable structures. In the light of a more accurate orbit description of the F ring core we find evidence for a ring that becomes dynamically more active as the system approaches anti-apse alignment with Prometheus. This is consistent with the observed increased strand activity. A recent strand that morphologically resembles the core is the strongest seen to date and points to the intricate relation between core and strands indicating the strands' violent creation. Using more than 150 identifications of various strands, we trace their kinematics and infer dynamical timescales and photometric properties. Implications for the dynamical evolution of the F ring will be discussed. This research was supported by the Cassini Project.

  11. Physics of Jupiter's Gossamer Rings

    NASA Astrophysics Data System (ADS)

    Hamilton, Douglas P.; Krueger, H.

    2007-10-01

    Thebe's gossamer ring, the outermost and faintest of Jupiter's rings, has an outward extension that we have previously argued is due to a shadow resonance (Hamilton 2003, DPS meeting #35, #11.09). A shadow resonance arises from the abrupt shutoff of photoelectric charging when a dust particle enters Jupiter's shadow which, in turn, affects the strength of the electromagnetic perturbation from the planet's intense magnetic field. The result is a coupled oscillation between a particle's orbital eccentricity and its semimajor axis. Ring material spreads outward from Thebe while maintaining its vertical thickness just as observed by Galileo imaging. In addition to cameras, the Galileo spacecraft was also equipped with dust and plasma detectors. The spacecraft made two passes through the ring and its dust detector found that 1) dust fluxes drop immediately interior to Thebe's orbit, 2) some grains have inclinations in excess of 20 degrees and 3) submicron particles are present in the Amalthea ring in much greater numbers than in the Thebe ring. These findings can all be explained in the context of our shadow resonance model: the inner boundary is a direct consequence of the conservation of the Electromagnetic Jacobi Constant, the high inclinations are forced by a vertical resonance, and the excess submicron particles are a consequence of the weakening of electromagnetic forces in the vicinity of synchronous orbit. In this talk, we will present the data sets as well as detailed numerical simulations that back up these claims.

  12. Collar nut and thrust ring

    DOEpatents

    Lowery, Guy B.

    1991-01-01

    A collar nut comprises a hollow cylinder having fine interior threads at one end for threadably engaging a pump mechanical seal assembly and an inwardly depending flange at the other end. The flange has an enlarged portion with a groove for receiving an O-ring for sealing against the intrusion of pumpage from the exterior. The enlarged portion engages a thrust ring about the pump shaft for crushing a hard O-ring, such as a graphite O-ring. The hard O-ring seals the interior of the mechanical seal assembly and pump housing against the loss of lubricants or leakage of pumpage. The fine threads of the hollow cylinder provide the mechanical advantage for crushing the hard O-ring evenly and easily with a hand tool from the side of the collar nut rather than by tightening a plurality of bolts from the end and streamlines the exterior surface of the mechanical seal. The collar nut avoids the spatial requirements of bolt heads at the end of a seal and associated bolt head turbulence.

  13. Of Rings and Volcanoes

    NASA Astrophysics Data System (ADS)

    2002-01-01

    Office National d'Etudes et de Recherches Aérospatiales (ONERA) , Laboratoire d'Astrophysique de Grenoble (LAOG) and the DESPA and DASGAL laboratories of the Observatoire de Paris in France, in collaboration with ESO. The CONICA infra-red camera was built, under an ESO contract, by the Max-Planck-Institut für Astronomie (MPIA) (Heidelberg) and the Max-Planck Institut für Extraterrestrische Physik (MPE) (Garching) in Germany, in collaboration with ESO. Saturn - Lord of the rings ESO PR Photo 04a/02 ESO PR Photo 04a/02 [Preview - JPEG: 460 x 400 pix - 54k] [Normal - JPEG: 1034 x 800 pix - 200k] Caption : PR Photo 04a/02 shows the giant planet Saturn, as observed with the VLT NAOS-CONICA Adaptive Optics instrument on December 8, 2001; the distance was 1209 million km. It is a composite of exposures in two near-infrared wavebands (H and K) and displays well the intricate, banded structure of the planetary atmosphere and the rings. Note also the dark spot at the south pole at the bottom of the image. One of the moons, Tethys, is visible as a small point of light below the planet. It was used to guide the telescope and to perform the adaptive optics "refocussing" for this observation. More details in the text. Technical information about this photo is available below. This NAOS/CONICA image of Saturn ( PR Photo 04a/02 ), the second-largest planet in the solar system, was obtained at a time when Saturn was close to summer solstice in the southern hemisphere. At this moment, the tilt of the rings was about as large as it can be, allowing the best possible view of the planet's South Pole. That area was on Saturn's night side in 1982 and could therefore not be photographed during the Voyager encounter. The dark spot close to the South Pole is a remarkable structure that measures approximately 300 km across. It was only recently observed in visible light from the ground with a telescope at the Pic du Midi Observatory in the Pyrenees (France) - this is the first infrared image to

  14. Clinical efficacy of lumbar interbody fusion using a channel system combined with ozone therapy for the treatment of central-type L3-L4 lumbar disc herniation

    PubMed Central

    Wang, Yu; Sun, Hong; Qin, Shuzhen

    2017-01-01

    The clinical efficacy of minimally invasive lumbar interbody fusion via the intervertebral foramen combined with ozone (O3) therapy for the treatment of L3-L4 central-type lumbar disc herniation was explored. We recruited patients with sciatica who attended our hospital between July 2013 and October 2015 and underwent lumbar X-ray (anteroposterior and lateral view), lumbar flexion-extension radiographs, computed tomography, and magnetic resonance imaging after admission. Seventy-four patients with central-type lumbar disc herniation but no other complications were randomly selected and divided into the observation and control groups. The observation group comprised 37 patients treated with lumbar fusion using a channel system combined with O3 therapy, whereas the control group comprised 37 patients treated with lumbar fusion alone. The effects of the two therapies were evaluated using visual analog scale, Japanese Orthopaedic Association, and MacNab scores. There was no significant difference in scores between the two groups before surgery (P>0.05). The scores of the observation group after treatment were significantly lower than those before surgery and those of the control group (P<0.05). One patient in the observation group experienced no obvious improvement in symptoms after surgery, and two patients in the control group experienced postoperative recurrence; these three patients subsequently underwent laminectomy combined with planted bone fusion and internal fixation. There was no significant difference in total efficacy rates between the two groups (P>0.05). Lumbar fusion using a channel system combined with O3 therapy for the treatment of L3-L4 central-type lumbar disc herniation is safe and effective. It has the advantages of reduced trauma, fewer complications, and rapid pain relief, and it promotes the recovery of lumbar function. Strict mastery of the surgical indications is key to the success of the procedure; however, it is worth expanding its use in

  15. 1987 Volvo award in basic science. The morphology of the lumbar erector spinae.

    PubMed

    Macintosh, J E; Bogduk, N

    1987-09-01

    The lumbar erector spinae consists of two muscles--iliocostalis lumborum and longissimus thoracis--each with distinct thoracic and lumbar parts. The thoracic parts consist of tiny muscle bellies with segmental origins from the thorax and long caudal tendons that form the erector spinae aponeurosis. The lumbar fibers arise from the lumbar accessory processes and the L1-4 transverse processes, and insert independently of the erector spinae aponeurosis into the ilium. The intrinsic lumbar fibers of the erector spinae are poorly described in the literature, and the existence of the iliocostalis lumborum pars lumborum has rarely been recognized even though it constitutes a substantial portion of the total muscle mass acting directly on the lumbar vertebrae.

  16. Calibration method for lumbosacral dimensions in wearable sensor system of lumbar alignment.

    PubMed

    Tsuchiya, Yoshio; Kusaka, Takashi; Tanaka, Takayuki; Matsuo, Yoshikazu; Oda, Makoto; Sasaki, Tsukasa; Kamishima, Tamotsu; Yamanaka, Masanori

    2015-01-01

    Anteflexion of the spine is essential for many physical activities in everyday life. However, this motion places the lumbar disks under heavy load due to changes in the shape of the lumbar spine and can lead to low back pain. With the aim of reducing low back pain, here we developed a wearable sensor system that can estimate lumbosacral alignment and lumbar load by measuring the shape of the lumbar skin when the lumbosacral alignment changes. In addition, we used this system to measure the parameters of anteflexion and studied the change in dimensions of the lumbar spine from changes in posture. By determining the dimensions of the lumbosacral spine on an X-ray image, a lumbosacral dimensions calibration method based on body surface area and height was developed. By using this method, lumbosacral alignment and lumbar load could be accurately estimated using the wearable sensor system.

  17. Review of early clinical results and complications associated with oblique lumbar interbody fusion (OLIF).

    PubMed

    Phan, Kevin; Maharaj, Monish; Assem, Yusuf; Mobbs, Ralph J

    2016-09-01

    Lumbar interbody fusion represents an effective surgical intervention for patients with lumbar degenerative diseases, spondylolisthesis, disc herniation, pseudoarthrosis and spinal deformities. Traditionally, conventional open anterior lumbar interbody fusion and posterior/transforaminal lumbar interbody fusion techniques have been employed with excellent results, but each with their own advantages and caveats. Most recently, the antero-oblique trajectory has been introduced, providing yet another corridor to access the lumbar spine. Termed the oblique lumbar interbody fusion, this approach accesses the spine between the anterior vessels and psoas muscles, avoiding both sets of structures to allow efficient clearance of the disc space and application of a large interbody device to afford distraction for foraminal decompression and endplate preparation for rapid and thorough fusion. This review aims to summarize the early clinical results and complications of this new technique and discusses potential future directions of research.

  18. Neuromuscular disorders associated with static lumbar flexion: a feline model.

    PubMed

    Solomonow, M; Zhou, B; Baratta, R V; Zhu, M; Lu, Y

    2002-04-01

    Static flexion of the lumbar spine with constant load applied to the viscoelastic structures for 20 minutes and for 50 minutes resulted in development of spasms and inhibition in the multifidus muscles (e.g., deep erector spinae) and in creep of the supraspinous ligament in the feline model. The development of spasms and inhibition was not dependent on load magnitude. It is suggested that occupational and sports activities which require prolonged static lumbar flexion within the physiological range can cause a "sprain"-like injury to the ligaments, which in turn reflexively induce spasms and inhibition in some erector spinae muscles. Such disorder may take a long time to recover, in the order of days to weeks, depending on the level of creep developed in the tissues.

  19. Lumbar facet fracture in an adolescent ice hockey player.

    PubMed

    Shaffer, W O; Taylor, M R; Sundaram, M

    1999-11-01

    A 14-year-old boy was checked hard as he was winding up to shoot in an ice hockey game. He experienced low-back pain during the game but when examined later for complaints of pain and fever, he denied trauma. Plain x-rays were normal, but a bone scan showed increased uptake at L-3. MRI evaluation revealed a lumbar mass; a CT scan showed the mass to be a hematoma and edema secondary to a facet fracture. Acute severe back pain in a hockey player should prompt a careful history and a search for musculoskeletal injury. When trauma in the lumbar spine is suspected and plain radiographs are nondiagnostic, CT scans are more precise than MRI for diagnosing injury.

  20. Computer-aided diagnosis of lumbar stenosis conditions

    NASA Astrophysics Data System (ADS)

    Koompairojn, Soontharee; Hua, Kathleen; Hua, Kien A.; Srisomboon, Jintavaree

    2010-03-01

    Computer-aided diagnosis (CAD) systems are indispensable tools for patients' healthcare in modern medicine. Nevertheless, the only fully automatic CAD system available for lumbar stenosis today is for X-ray images. Its performance is limited due to the limitations intrinsic to X-ray images. In this paper, we present a system for magnetic resonance images. It employs a machine learning classification technique to automatically recognize lumbar spine components. Features can then be extracted from these spinal components. Finally, diagnosis is done by applying a Multilayer Perceptron. This classification framework can learn the features of different spinal conditions from the training images. The trained Perceptron can then be applied to diagnose new cases for various spinal conditions. Our experimental studies based on 62 subjects indicate that the proposed system is reliable and significantly better than our older system for X-ray images.

  1. PRIMARY LIPOSARCOMA OF THE LUMBAR SPINE: CASE REPORT

    PubMed Central

    de Moraes, Frederico Barra; Cardoso, André Luiz Passos; Tristão, Newton Antônio; Pimenta, Wilson Eloy; Daher, Sérgio; de Souza Carneiro, Siderley; Barbosa, Nathalia Parrode Machado; de Lima Malta, Nayanne; Ribeiro, Noara Barros

    2015-01-01

    We report a rare case of primary bone liposarcoma of the lumbar spine, for which only one case has been reported. A female patient, 60 years of age, with lumbar pain and left sciatalgy for six months. In the imaging exams, a destructive tumor was found in the L4 vertebral body, and magnetic resonance imaging (MRI) revealed a tumoral lesion with T1 hiposignal and T2 hypersignal. Histological diagnosis was difficult, and immunohistochemistry confirmed the diagnosis. Surgical treatment was performed with wide ressection, spinal cord decompression, and anterior and posterior fusion of L3 to L5 complemented by radiotherapy and chemotherapy. After three years, a computed tomography (CT) scan evidenced an expansive injury in the lung. Despite its rarity, liposarcoma should be considered in the differential diagnosis of sciatica and primary tumors of the spine. PMID:27027092

  2. Do cranial subdural hematomas migrate to the lumbar spine?

    PubMed

    Moscovici, S; Paldor, I; Ramirez de-Noriega, F; Itshayek, E; Shoshan, Y; Spektor, S; Attia, M

    2011-04-01

    We report a patient with minor head trauma-related bilateral hemispheric subdural hematoma (SDH) and subsequent delayed spinal SDH or presumed migration to the lumbar spine. An acutely confused 88-year-old man presented to the Emergency Department after minor head trauma. Head CT scan revealed a small hemispheric SDH. The patient was admitted for observation. CT scan 6 hours later showed bilateral SDH with extension to the tentorium. Three days later SDH had resolved leaving bilateral subdural hygromas. Local leg weakness localized to the lumbar spine developed on day 6; spinal CT scan and MRI revealed a posterior L5-S1 collection. A pure subacute subdural hematoma compressing the cauda equina was drained after an L5 laminectomy. His lower leg weakness improved. The patient was discharged to rehabilitation two weeks after surgery. Patients with traumatic SDH who develop late-onset neurological deterioration attributable to any region of the spine should be evaluated for spinal SDH.

  3. Spondylodiscitis Occurring after Diagnostic Lumbar Puncture: A Case Report

    PubMed Central

    Berkman, Mehmet Zafer

    2013-01-01

    Spondylodiscitis is a rare disease which is generally seen after long-term epidural catheterization. However, spondylidiscitis developing after diagnostic lumbar puncture is very rare. Early diagnosis has a crucial role in the management of the disease and inclines the morbidity rates. However, the diagnosis is often delayed due to the rarity and insidious onset of the disease usually presenting with low back pain which has a high frequency in the society. If it is diagnosed early before development of an abscess requiring surgery or neurological deficit, it responds to antimicrobial therapy quite well. We report 66-year-old male case of spondylodiscitis developing after diagnostic lumbar puncture. The patient was treated with antimicrobial therapy. After antimicrobial therapy, findings of spondylodiscitis were completely resolved and no recurrence was seen in the period of 9-month followup. PMID:23476837

  4. Interobserver reproducibility of radiographic evaluation of lumbar spine instability

    PubMed Central

    Segundo, Saulo de Tarso de Sá Pereira; Valesin, Edgar Santiago; Lenza, Mario; Santos, Durval do Carmo Barros; Rosemberg, Laercio Alberto; Ferretti, Mario

    2016-01-01

    ABSTRACT Objective: To measure the interobserver reproducibility of the radiographic evaluation of lumbar spine instability. Methods: Measurements of the dynamic radiographs of the lumbar spine in lateral view were performed, evaluating the anterior translation and the angulation among the vertebral bodies. The tests were evaluated at workstations of the organization, through the Carestream Health Vue RIS (PACS), version 11.0.12.14 Inc. 2009© system. Results: Agreement in detecting cases of radiographic instability among the observers varied from 88.1 to 94.4%, and the agreement coefficients AC1 were all above 0.8, indicating excellent agreement. Conclusion: The interobserver analysis performed among orthopedic surgeons with different levels of training in dynamic radiographs of the spine obtained high reproducibility and agreement. However, some factors, such as the manual method of measurement and the presence of vertebral osteophytes, might have generated a few less accurate results in this comparative evaluation of measurements. PMID:27759827

  5. Paraplegia by acute cervical disc protrusion after lumbar spine surgery.

    PubMed

    Chen, Sheng-Huan; Hui, Yu-Ling; Yu, Chong-Ming; Niu, Chi-Chien; Lui, Ping-Wing

    2005-04-01

    Non-traumatic paraplegia caused by herniation of the cervical intervertebral disc is an uncommon postoperative complication. A patient with claudication and radiculopathy was scheduled for lumbar laminectomy due to spinal stenosis. Postoperatively, numbness below T6 was found in his both legs of the patient. MRI showed a protruded intervertebral disc between C6 and C7. Despite urgent disectomy, the patient's lower extremities remained paralyzed without significant improvement for 3 months. Loss of muscle support during general anesthesia, excessive neck extension during endotracheal intubation and positioning, as well as bucking and agitation are believed as triggering factors for the protrusion of the cervical disc. We suggest that a complete history taking and physical examination be accomplished in patients scheduled for lumbar spine surgery in order to exclude coexisting cervical spine disorders. In addition, skillful endotracheal intubation and careful neck positioning are mandatory for patients receiving surgery in the prone position.

  6. Accretion in Saturn's F Ring

    NASA Astrophysics Data System (ADS)

    Meinke, B. K.; Esposito, L. W.; Stewart, G.

    2012-12-01

    Saturn's F ring is the solar system's principal natural laboratory for direct observation of accretion and disruption processes. The ring resides in the Roche zone, where tidal disruption competes with self-gravity, which allows us to observe the lifecycle of moonlets. Just as nearby moons create structure at the B ring edge (Esposito et al. 2012) and the Keeler gap (Murray 2007), the F ring "shepherding" moons Prometheus and Pandora stir up ring material and create observably changing structures on timescales of days to decades. In fact, Beurle et al (2010) show that Prometheus makes it possible for "distended, yet gravitationally coherent clumps" to form in the F ring, and Barbara and Esposito (2002) predicted a population of ~1 km bodies in the ring. In addition to the observations over the last three decades, the Cassini Ultraviolet Imaging Spectrograph (UVIS) has detected 27 statistically significant features in 101 occultations by Saturn's F ring since July 2004. Seventeen of those 27 features are associated with clumps of ring material. Two features are opaque in occultation, which makes them candidates for solid objects, which we refer to as Moonlets. The 15 other features partially block stellar signal for 22 m to just over 3.7 km along the radial expanse of the occultation. Upon visual inspection of the occultation profile, these features resemble Icicles, thus we will refer to them as such here. The density enhancements responsible for such signal attenuations are likely due to transient clumping of material, evidence that aggregations of material are ubiquitous in the F ring. Our lengthy observing campaign reveals that Icicles are likely transient clumps, while Moonlets are possible solid objects. Optical depth is an indicator of clumping because more-densely aggregated material blocks more light; therefore, it is natural to imagine moonlets as later evolutionary stage of icicle, when looser clumps of material compact to form a feature that appears

  7. 21 CFR 880.6200 - Ring cutter.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES....6200 Ring cutter. (a) Identification. A ring cutter is a device intended for medical purposes that is used to cut a ring on a patient's finger so that the ring can be removed. The device incorporates...

  8. 21 CFR 880.6200 - Ring cutter.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES....6200 Ring cutter. (a) Identification. A ring cutter is a device intended for medical purposes that is used to cut a ring on a patient's finger so that the ring can be removed. The device incorporates...

  9. Study for ILC Damping Ring at KEKB

    SciTech Connect

    Flanagan, J.W.; Fukuma, H.; Kanazawa, K.I.; Koiso, H.; Masuzawa, M.; Ohmi, Kazuhito; Ohnishi, Y.; Oide, Katsunobu; Suetsugu, Y.; Tobiyama, M.; Pivi, M.; /SLAC

    2011-11-04

    ILC damping ring consists of very low emittance electron and positron storage rings. It is necessary for ILC damping ring to study electron cloud effects in such low emittance positron ring. We propose a low emittance operation of KEKB to study the effects.

  10. Double acting stirling engine piston ring

    DOEpatents

    Howarth, Roy B.

    1986-01-01

    A piston ring design for a Stirling engine wherein the contact pressure between the piston and the cylinder is maintained at a uniform level, independent of engine conditions through a balancing of the pressure exerted upon the ring's surface and thereby allowing the contact pressure on the ring to be predetermined through the use of a preloaded expander ring.

  11. Plasma deposited rider rings for hot displacer

    DOEpatents

    Kroebig, Helmut L.

    1976-01-01

    A hot cylinder for a cryogenic refrigerator having two plasma spray deposited rider rings of a corrosion and abrasion resistant material provided in the rider ring grooves, wherein the rider rings are machined to the desired diameter and width after deposition. The rider rings have gas flow flats machined on their outer surface.

  12. [MRI appearance of lumbar epidural abscesses: report of three cases].

    PubMed

    Semlali, S; Fikri, M; Nassar, I; El Quessar, A; El Hassani, Mr; Chakir, N; Jiddane, M

    2004-03-01

    The authors report three cases of non-tuberculous epidural abscess. Presenting symptoms included lumbar back pain, muscle spasms, soft tIssue swelling, and neurological deficits in all three cases. MR imaging was helpful for diagnosis and showed involvement of perivertebral soft tissues and an epidural abscess of variable size. There was no significant involvement of intervertebral disks or vertebrae. Diagnosis was confirmed by bacteriologic exam. Clinical outcome was favourable with antibiotic treatment.

  13. [Microsurgery in lumbar disk operations. Possibilities, methods and results].

    PubMed

    Schwetlick, G

    1998-07-01

    The frequency of lumbar disc hemiation amounts to 5.1% with the male and 3.7% with the female population. Because of the often long-time pain-conditional impairment of the patients as well as the varied therapy-possibilities, the treatment of the ruptured lumbar intervertebral disc represents a special challenge. The indication to the operation for the lumbar disk-herniation results from the malfunctions of the nerve roots, the pains, as well as the temporal course of the symptoms. New and important developments have given the introduction of micro-surgical operation-techniques into the orthopedics. This development has led to it that many orthopedists and neurosurgeons the micro-surgical operation-technique prefers. Important for the micro-surgical lumbar discectomy is the operation-microscope, a good preoperative diagnostics as well as a particular micro-surgical operation-instrument. Through the different enlargement-possibilities of the operation-microscope, all anatomical structures can increase and are done visibly for the surgeon as well as the assistant. Intraoperative injuries of the dura as well as the spinal-nerves are certainly avoided hereby. The micro-surgical discectomie requires no longer time like the conventional operation of the disk. The postoperative stay in the hospital as well as the time of the work-incompetence is reduced. Postoperative inflammations of the disk-area as well as renewed operations are rarer with the microchirurgischen technique. If an operation is necessary, so this should not be out-hesitated too long in order to avoid bed results.

  14. Is epidural steroid injection effective for degenerative lumbar spinal stenosis?

    PubMed

    Flores, Sebastián; Molina, Marcelo

    2015-11-16

    There are several nonsurgical alternatives to treat radicular pain in degenerative lumbar spinal stenosis. Epidural steroid injections have been used for several decades, but the different studies have shown variable effects. Searching in Epistemonikos database, which is maintained by screening 30 databases, we identified nine systematic reviews including seven pertinent randomized controlled trials. We concluded epidural steroid injection probably leads to little or no effect on reducing radicular pain of spinal stenosis.

  15. Rapidly progressive lumbar subdural empyema following acromial bursal injection.

    PubMed

    Coumans, Jean-Valery C E; Walcott, Brian P

    2011-11-01

    Spinal subdural empyemas are rare. We describe a 53-year-old male who presented with back pain, mental status changes, and sepsis. Five days prior he had undergone a triamcinolone and lidocaine injection of the acromial bursa. He also had a remote history of epidural steroid injection for thoracic back pain. Two lumbar MRI conducted 62 hours apart revealed a newly developed subdural empyema that was successfully treated with surgical evacuation and post-operative antibiotics.

  16. Concentric ring flywheel without expansion separators

    DOEpatents

    Kuklo, Thomas C.

    1999-01-01

    A concentric ring flywheel wherein the adjacent rings are configured to eliminate the need for differential expansion separators between the adjacent rings. This is accomplished by forming a circumferential step on an outer surface of an inner concentric ring and forming a matching circumferential step on the inner surface of an adjacent outer concentric ring. During operation the circumferential steps allow the rings to differentially expand due to the difference in the radius of the rings without the formation of gaps therebetween, thereby eliminating the need for expansion separators to take up the gaps formed by differential expansion.

  17. Concentric ring flywheel without expansion separators

    DOEpatents

    Kuklo, T.C.

    1999-08-24

    A concentric ring flywheel wherein the adjacent rings are configured to eliminate the need for differential expansion separators between the adjacent rings. This is accomplished by forming a circumferential step on an outer surface of an inner concentric ring and forming a matching circumferential step on the inner surface of an adjacent outer concentric ring. During operation the circumferential steps allow the rings to differentially expand due to the difference in the radius of the rings without the formation of gaps therebetween, thereby eliminating the need for expansion separators to take up the gaps formed by differential expansion. 3 figs.

  18. Lumbar Aspergillus osteomyelitis mimicking pyogenic osteomyelitis in an immunocompetent adult.

    PubMed

    Yoon, Kyeong-Wook; Kim, Young-Jin

    2015-04-01

    Spinal Aspergillus osteomyelitis is rare and occurs mostly in immunocompromised patients, but especially very rare in immunocompetent adult. This report presents a case of lumbar vertebral osteomyelitis in immunocompetent adult. A 53-year-old male who had no significant medical history was admitted due to complaints of back pain radiating to the flank for the last 3 months, followed by a progressive motor weakness of both lower limbs. Lumbar magnetic resonance imaging (MRI) demonstrated osteomyelitis and diskitis, suspected to be a pyogenic condition rather than a tuberculosis infection. Despite antibiotic treatment for several weeks, the symptoms worsened, and finally, open surgery was performed. Surgical biopsy revealed an Aspergillus infection and medical treatment with amphotericin B was started. It can be diagnosed early through an MRI; biopsy is very important but difficult, and making the correct differential diagnosis is essential for avoiding unexpected complications. The authors report a case of lumbar Aspergillus osteomyelitis in an immunocompetent adult and reviewed previously described cases of spinal aspergillosis.

  19. Flexible Stabilisation of the Degenerative Lumbar Spine Using PEEK Rods

    PubMed Central

    Benezech, Jacques; Garlenq, Bruno; Larroque, Gilles

    2016-01-01

    Posterior lumbar interbody fusion using cages, titanium rods, and pedicle screws is considered today as the gold standard of surgical treatment of lumbar degenerative disease and has produced satisfying long-term fusion rates. However this rigid material could change the physiological distribution of load at the instrumental and adjacent segments, a main cause of implant failure and adjacent segment disease, responsible for a high rate of further surgery in the following years. More recently, semirigid instrumentation systems using rods made of polyetheretherketone (PEEK) have been introduced. This clinical study of 21 patients focuses on the clinical and radiological outcomes of patients with lumbar degenerative disease treated with Initial VEOS PEEK®-Optima system (Innov'Spine, France) composed of rods made from PEEK-OPTIMA® polymer (Invibio Biomaterial Solutions, UK) without arthrodesis. With an average follow-up of 2 years and half, the chances of reoperation were significantly reduced (4.8%), quality of life was improved (ODI = 16%), and the adjacent disc was preserved in more than 70% of cases. Based on these results, combined with the biomechanical and clinical data already published, PEEK rods systems can be considered as a safe and effective alternative solution to rigid ones. PMID:26981285

  20. Lumbar cisternography in evaluation of hydrocephalus in the preterm infant

    SciTech Connect

    Donn, S.M.; Roloff, D.W.; Keyes, J.W. Jr.

    1983-10-01

    Radionuclide lumbar cisternography using indium 111-diethylenetriamine pentaacetic acid (111In-DTPA) and a mobile gamma-camera with a converging collimator was utilized as a bedside procedure to evaluate CSF dynamics and the patency of the cerebral ventricular system in 30 preterm infants with hydrocephalus. Serial images of the brain were obtained at 0, 1, 2, 6, 24, and 48 hours after instillation of the isotope in the lumbar subarachnoid space. Three distinct patterns were seen. Infants with posthemorrhagic hydrocephalus displayed prompt ventricular filling but markedly delayed emptying with minimal flow over the cerebral convexities. Infants with ventriculomegaly secondary to suspected brain atrophy or periventricular leukomalacia demonstrated a pattern of prompt ventricular filling, delayed emptying, but with flow present over the convexities. An infant with noncommunicating hydrocephalus secondary to an Arnold-Chiari malformation showed a pattern of complete obstruction with no ventricular filling. Radionuclide lumbar cisternography appears to be a safe, well-tolerated procedure which produces images of sufficient resolution to provide valuable information about CSF dynamics, delineating basal cisternae, ventricles, and subarachnoid flow paths.

  1. Sacral Stress Fracture following the Bone Union of Lumbar Spondylolysis

    PubMed Central

    Imaizumi, Hideki; Takano, Hiroyuki; Saitoh, Hideo; Murakami, Taishi; Kanabuchi, Ryuichi; Sekiya, Motohiko

    2016-01-01

    While 22 articles have reported on sacral stress fractures, it is a rare injury and its etiology is not well known. We present the case of a 16-year-old male who presented with low back pain in 2015. He was a high school soccer player with a previous history of a bilateral L5 lumbar spondylolysis in 2014. The patient refrained from soccer and wore a brace for six months. Two months after restarting soccer, he again complained of low back pain. After 1 year, a lumbar spine computed tomography revealed the bone union of the spondylolysis. At his first visit to our hospital, his general and neurological conditions were normal and laboratory data were within the normal range. Sacral coronal magnetic resonance imaging (MRI) of the left sacral ala revealed an oblique lineal signal void surrounding bone marrow edema. Based on his symptoms, sports history, and MRI, he was diagnosed with a sacral stress fracture. He again refrained from soccer; his low back pain soon improved, and, after 1 year, the abnormal signal change had disappeared on sacral MRI. Recurrent low back pain case caused by a sacral stress fracture occurring after the bone union of lumbar spondylolysis is uncommon. PMID:28050170

  2. Predictors of Reoperation after Microdecompression in Lumbar Spinal Stenosis

    PubMed Central

    Hwang, Hee-Jong; Lee, Gwang-Soo; Heo, June-Young; Chang, Jae-Chil

    2016-01-01

    Objective The risk factors of reoperation after microdecompression (MD) for lumbar spinal stenosis (LSS) are unclear. In this study, we presented the outcomes of MD for degenerative LSS and investigated the risk factors associated with reoperation. Methods A retrospective review was conducted using the clinical records and radiographs of patients with LSS who underwent MD. For clinical evaluation, we used the Japanese Orthopedic Association (JOA) scoring system for low back pain, body mass index, and Charlson comorbidity index. For radiological evaluation, disc height, facet angle, and sagittal rotation angle were measured in operated segments. Also the Modic change and Pfirrmann grade for degeneration in the endplate and disc were scored. Results Forty-three patients aged 69±9 years at index surgery were followed for 48±25 months. The average preoperative JOA score was 6.9±1.6 points. The score improved to 9.1±2.1 points at the latest follow-up (p<0.001). Seven patients (16.3%) underwent reoperation. Clinical and radiological factors except operation level and Pfirrmann grade showed a p-value >0.1. Patients with Pfirrmann grade IV and lower lumbar segment had a 29.1% rate of reoperation (p=0.001), whereas patients without these factors had a 0% rate of reoperation. Conclusion Moderate disk degeneration (Pfirrmann IV) in lower lumbar segments is a risk factor of disk herniation or foraminal stenosis requiring reoperation after MD in LSS. PMID:28127375

  3. Flexible Stabilisation of the Degenerative Lumbar Spine Using PEEK Rods.

    PubMed

    Benezech, Jacques; Garlenq, Bruno; Larroque, Gilles

    2016-01-01

    Posterior lumbar interbody fusion using cages, titanium rods, and pedicle screws is considered today as the gold standard of surgical treatment of lumbar degenerative disease and has produced satisfying long-term fusion rates. However this rigid material could change the physiological distribution of load at the instrumental and adjacent segments, a main cause of implant failure and adjacent segment disease, responsible for a high rate of further surgery in the following years. More recently, semirigid instrumentation systems using rods made of polyetheretherketone (PEEK) have been introduced. This clinical study of 21 patients focuses on the clinical and radiological outcomes of patients with lumbar degenerative disease treated with Initial VEOS PEEK(®)-Optima system (Innov'Spine, France) composed of rods made from PEEK-OPTIMA(®) polymer (Invibio Biomaterial Solutions, UK) without arthrodesis. With an average follow-up of 2 years and half, the chances of reoperation were significantly reduced (4.8%), quality of life was improved (ODI = 16%), and the adjacent disc was preserved in more than 70% of cases. Based on these results, combined with the biomechanical and clinical data already published, PEEK rods systems can be considered as a safe and effective alternative solution to rigid ones.

  4. Lumbar facet cyst resolution following anterior interbody fusion.

    PubMed

    Massey, Gene M; Caputo, Adam M; Michael, Keith W; Isaacs, Robert E; Brown, Christopher R

    2013-12-01

    Facet cysts are a relatively common source of neural compression in the lumbar spine. Open decompression and fusion are frequently used to treat the stenosis and instability associated with this pathology. Recently, anterior lumbar interbody fusion (ALIF) has increased in popularity for the treatment of lumbar degenerative conditions. ALIF may achieve indirect decompression of the neural elements with less surgical morbidity than conventional open approaches. To date, there are no published reports describing the use of indirect decompression or interbody fusion for the treatment of facet cysts. We report a patient who developed an L4-L5 facet cyst secondary to degenerative changes and spondylolisthesis. ALIF with posterior instrumentation was used to address his condition. Six months after surgery, the patient had complete resolution of his symptoms. MRI revealed complete resolution of the facet cyst. This patient provides previously unreported evidence that interbody fusion alone may result in facet cyst resolution. Clinical studies are needed to evaluate if interbody fusion can consistently relieve the symptoms associated with facet cysts without the use of direct decompression.

  5. Rate-dependent fracture characteristics of lumbar vertebral bodies.

    PubMed

    Stemper, Brian D; Yoganandan, Narayan; Baisden, Jamie L; Umale, Sagar; Shah, Alok S; Shender, Barry S; Paskoff, Glenn R

    2015-01-01

    Experimental testing incorporating lumbar columns and isolated components is essential to advance the understanding of injury tolerance and for the development of safety enhancements. This study incorporated a whole column axial acceleration model and an isolated vertebral body model to quantify compression rates during realistic loading and compressive tolerance of vertebrae. Eight lumbar columns and 53 vertebral bodies from 23 PMHS were used. Three-factor ANOVA was used to determine significant differences (p<0.05) in physiologic and failure biomechanics based on compression rate, spinal level, and gender. Results demonstrated a significant increase in ultimate force (i.e., fracture) from lower to higher compression rates. Ultimate stress also increased with compression rate. Displacement and strain to failure were consistent at both compression rates. Differences in ultimate mechanics between vertebral bodies obtained from males and females demonstrated non-significant trends, with female vertebral bodies having lower ultimate force that would be associated with decreased injury tolerance. This was likely a result of smaller vertebrae in that population. Combined with existing literature, results presented in this manuscript contribute to the understanding of lumbar spine tolerance during axial loading events that occur in both military and civilian environments with regard to effects of compression rate and gender.

  6. A Novel Nonpedicular Screw-Based Fixation in Lumbar Spondylolisthesis

    PubMed Central

    2017-01-01

    Objective. The authors present the clinical results obtained in patients who underwent interspinous fusion device (IFD) implantation following posterior lumbar interbody fusion (PLIF). The purpose of this study is investigating the feasibility of IFD with PLIF in the treatment of lumbar spondylolisthesis. Methods. Between September 2013 and November 2014, 39 patients underwent PLIF and subsequent IFD (Romeo®2 PAD, Spineart, Geneva, Switzerland) implantation. Medical records of these patients were retrospectively reviewed to collect relevant data such as blood loss, operative time, and length of hospital stay. Radiographs and clinical outcome were evaluated 6 weeks and 12 months after surgery. Results. All 39 patients were followed up for more than one year. There were no major complications such as dura tear, nerve injuries, cerebrospinal fluid leakage, or deep infection. Both interbody and interspinous fusion could be observed on radiographs one year after surgery. However, there were 5 patients having early retropulsion of interbody fusion devices. Conclusion. The interspinous fusion device appears to achieve posterior fixation and facilitate lumbar fusion in selected patients. However, further study is mandatory for proposing a novel anatomic and radiological scoring system to identify patients suitable for this treatment modality and prevent postoperative complications. PMID:28164125

  7. Angiogenesis in the degeneration of the lumbar intervertebral disc

    PubMed Central

    David, Gh; Iencean, SM; Mohan, A

    2010-01-01

    The goal of the study is to show the histological and biochemical changes that indicate the angiogenesis of the intervertebral disc in lumbar intervertebral disc hernia and the existence of epidemiological correlations between these changes and the risk factors of lumbar intervertebral disc hernia, as well as the patient's quality of life (QOL). We have studied 50 patients aged between 18 and 73 years old, who have undergone lumbar intervertebral disc hernia surgery, making fibroblast growth factor and vascular endothelial growth factor level measurements, as elements in the process of appreciating the disc angiogenesis. Also, pre–surgery and post–surgery QOL has been measured, as well as the intensity of the pain syndrome. We have identified factors capable of stimulating vascular endothelial growth (VEGF, FGF–2) for the examined disc material, but histological examination did not show angiogenesis. The process of angiogenesis at the degenerated intervertebral disc level affects the patient's quality of life both pre and postoperatively, and may be a predictive factor for the post–operative results. Patients can prevent the appearance of angiogenesis type degenerative processes of the intervertebral disc by avoiding angiogenesis correlated factors (weight control, physical effort, and smoking). PMID:20968201

  8. Fractal analysis of lumbar vertebral cancellous bone architecture.

    PubMed

    Feltrin, G P; Macchi, V; Saccavini, C; Tosi, E; Dus, C; Fassina, A; Parenti, A; De Caro, R

    2001-11-01

    Osteoporosis is characterized by bone mineral density (BMD) decreasing and spongy bone rearrangement with consequent loss of elasticity and increased bone fragility. Quantitative computed tomography (QCT) quantifies bone mineral content but does not describe spongy architecture. Analysis of trabecular pattern may provide additional information to evaluate osteoporosis. The aim of this study was to determine whether the fractal analysis of the microradiography of lumbar vertebrae provides a reliable assessment of bone texture, which correlates with the BMD. The lumbar segment of the spine was removed from 22 cadavers with no history of back pain and examined with standard x-ray, traditional tomography, and quantitative computed tomography to measure BMD. The fractal dimension, which quantifies the image fractal complexity, was calculated on microradiographs of axial sections of the fourth lumbar vertebra to determine its characteristic spongy network. The relationship between the values of the BMD and those of the fractal dimension was evaluated by linear regression and a statistically significant correlation (R = 0.96) was found. These findings suggest that the application of fractal analysis to radiological analyses can provide valuable information on the trabecular pattern of vertebrae. Thus, fractal dimensions of trabecular bone structure should be considered as a supplement to BMD evaluation in the assessment of osteoporosis.

  9. Conservative Management of Ureteral Injury Caused by a Lumbar Osteophyte

    PubMed Central

    Brekhus, Michael

    2016-01-01

    Abstract Background: Osteophytes are bony outgrowths commonly found on lumbar vertebrae. They rarely produce complications with the most common complication being nerve entrapment, but rarer complications including aorta or inferior vena cava rupture, superior mesenteric artery syndrome, compression of the iliopsoas muscle, and cerebrospinal fluid leaks have been described. Rare cases affecting the ureter resulting in ureteral colic or extravasation of urine have been described. Case Presentation: We describe a case in which a lumbar osteophyte bridging the L4 and L5 disks was encircling the ureter and minor trauma caused a ureteral injury, resulting in urine extravasation into the L4 and L5 disks space and the retroperitoneum. Owing to the comorbidities of this patient, this case was treated conservatively with stenting and the patient has suffered no further complications. Conclusion: This is a rare complication of a lumbar osteophyte but should be considered as a potential cause of ureter injury. Treatment should be individualized by patient preference and comorbidities, as some patients would elect to pursue more aggressive therapy whereas others would incline for conservative measures. PMID:28078328

  10. Analysis of Efficacy Differences between Caudal and Lumbar Interlaminar Epidural Injections in Chronic Lumbar Axial Discogenic Pain: Local Anesthetic Alone vs. Local Combined with Steroids

    PubMed Central

    Manchikanti, Laxmaiah; Pampati, Vidyasagar; Benyamin, Ramsin M.; Boswell, Mark V.

    2015-01-01

    Study Design: Comparative assessment of randomized controlled trials of caudal and lumbar interlaminar epidural injections in chronic lumbar discogenic pain. Objective: To assess the comparative efficacy of caudal and lumbar interlaminar approaches of epidural injections in managing axial or discogenic low back pain. Summary of Background Data: Epidural injections are commonly performed utilizing either a caudal or lumbar interlaminar approach to treat chronic lumbar axial or discogenic pain, which is pain exclusive of that associated with a herniated intervertebral disc, or that is due to degeneration of the zygapophyseal joints, or due to dysfunction of the sacroiliac joints, respectively. The literature on the efficacy of epidural injections in managing chronic axial lumbar pain of presumed discogenic origin is limited. Methods: The present analysis is based on 2 randomized controlled trials of chronic axial low back pain not caused by disc herniation, radiculitis, or facet joint pain, utilizing either a caudal or lumbar interlaminar approach, with a total of 240 patients studied, and a 24-month follow-up. Patients were assigned to receive either local anesthetic only or local anesthetic with a steroid in each 60 patient group. Results: The primary outcome measure was significant improvement, defined as pain relief and functional status improvement of at least 50% from baseline, which was reported at 24-month follow-ups in 72% who received local anesthetic only with a lumbar interlaminar approach and 54% who received local anesthetic only with a caudal approach. In patients receiving local anesthetic with a steroid, the response rate was 67% for those who had a lumbar interlaminar approach and 68% for those who had a caudal approach at 12 months. The response was significantly better in the lumbar interlaminar group who received local anesthetic only, 77% versus 56% at 12 months and 72% versus 54% at 24 months. Conclusion: This assessment shows that in patients

  11. Treatment of lumbar disc herniation by percutaneous laser disc decompression (PLDD) and modified PLDD

    NASA Astrophysics Data System (ADS)

    Chi, Xiao fei; Li, Hong zhi; Wu, Ru zhou; Sui, Yun xian

    2005-07-01

    Objective: To study the micro-invasive operative method and to compare the effect of treatment of PLDD and modified PLDD for Lumbar Disc Herniation. Method: Vaporized part of the nucleus pulposus in single or multiple point after acupuncture into lumbar disc, to reach the purpose of the decompression of the lumbar disc. Result: Among the 19 cases of the regular PLDD group, the excellent and good rate was 63.2%, and among the 40 cases of the modified PLDD group, the excellent and good rate was 82.5%. Conclusion: The modified PLDD has good effect on the treatment for lumbar disc herniation.

  12. Intrinsic structure in Saturn's rings

    NASA Astrophysics Data System (ADS)

    Albers, N.

    2015-10-01

    Saturn's rings are the most prominent in our Solar system and one example of granular matter in space. Dominated by tides and inelastic collisions the system is highly flattened being almost 300000km wide while only tens of meters thick. Individual particles are composed of primarily water ice and range from microns to few tens of meters in size. Apparent patterns comprise ringlets, gaps, kinematic wakes, propellers, bending waves, and the winding spiral arms of density waves. These large-scale structures are perturbations foremost created by external as well as embedded moons. Observations made by the Cassini spacecraft currently in orbit around Saturn show these structures in unprecedented detail. But high-resolution measurements reveal the presence of small-scale structures throughout the system. These include self-gravity wakes (50-100m), overstable waves (100-300m), subkm structure at the A and B ring edges, "straw" and "ropy" structures (1-3km), and the C ring "ghosts". Most of these had not been anticipated and are found in perturbed regions, driven by resonances with external moons, where the system undergoes periodic phases of compression and relaxation that correlate with the presence of structure. High velocity dispersion and the presence of large clumps imply structure formation on time scales as short as one orbit (about 10 hours). The presence of these intrinsic structures is seemingly the response to varying local conditions such as internal density, optical depth, underlying particle size distribution, granular temperature, and distance from the central planet. Their abundance provides evidence for an active and dynamic ring system where aggregation and fragmentation are ongoing on orbital timescales. Thus a kinetic description of the rings may be more appropriate than the fluid one. I will present Cassini Ultraviolet Spectrometer (UVIS) High Speed Photometer (HSP) occultations, Voyager 1 and 2 Imaging Science Subsystem (ISS), and high

  13. Archiving of Planetary Ring Data

    NASA Technical Reports Server (NTRS)

    Elliot, James L.

    2001-01-01

    Stellar occultation data provide our only Earth-based means of probing planetary rings at kilometer spatial resolution. The occultation data archive at MIT contains original data and analysis products of stellar occultations by the ring systems of the planets Jupiter, Saturn, Uranus, and Neptune observed by members of the group (and other groups) from 1977 to the present. During this time period, several media have been used to record and store the original and processed data: (1) chart records; (2) printed output, (3) audio reel tape; (4) audio cassette tape; (5) 7-track, 1/2-inch computer tape; (6) 9-track, 1/2-inch computer tape at 800, 1600, and 6250 bpi; (7) NOVA disk platters (2.5 and 5.0 Mbyte); (8) write once optical disks; (9) punched cards; and (10) read-write optical disks. With the rapid change of computer technology over this time period, some of these media have become not only obsolete, but nearly extinct. In particular, it has become nearly impossible to find any facilities that can still read 800 bpi tapes, which contain the only copies of several important data sets for the ring system of Uranus. In particular, we have an extensive ring data collection that includes data sets for the following Uranian ring occultations: U0, U11, U12, U13, U14, U25, U17, and U36.

  14. Hydrodynamic Simulations of Planetary Rings

    NASA Astrophysics Data System (ADS)

    Miller, Jacob; Stewart, G. R.; Esposito, L. W.

    2013-10-01

    Simulations of rings have traditionally been done using N-body methods, granting insight into the interactions of individual ring particles on varying scales. However, due to the scale of a typical ring system and the sheer number of particles involved, a global N-body simulation is too computationally expensive, unless particle collisions are replaced by stochastic forces (Bromley & Kenyon, 2013). Rings are extraordinarily flat systems and therefore are well-suited to existing geophysical shallow-water hydrodynamics models with well-established non-linear advection methods. By adopting a general relationship between pressure and surface density such as a polytropic equation of state, we can modify the shallow-water formula to treat a thin, compressible, self-gravitating, shearing fluid. Previous hydrodynamic simulations of planetary rings have been restricted to axisymmetric flows and therefore have not treated the response to nonaxisymmetric perturbations by moons (Schmidt & Tscharnuter 1999, Latter & Ogilvie 2010). We seek to expand on existing hydrodynamic methods and, by comparing our work with complementary N-body simulations and Cassini observations, confirm the veracity of our results at small scales before eventually moving to a global domain size. We will use non-Newtonian, dynamically variable viscosity to model the viscous transport caused by unresolved self-gravity wakes. Self-gravity will be added to model the dynamics of large-scale structures, such as density waves and edge waves. Support from NASA Outer Planets and Planetary Geology and Geophysics programs is gratefully acknowledged.

  15. Storage ring working group report

    SciTech Connect

    Krinsky, S.

    1997-01-01

    Over the last two decades great progress has been made in the development of storage rings with small transverse emittance. It is now a good time to consider the possibility of achieving very short bunches m storage rings. From the perspective of synchrotron radiation source development, there are at least two motivations for obtaining short electron bunches: (1) the generation of sub- picosecond x-ray pulses and (2) the coherent emission of sub- picosecond pulses of far infrared radiation. A useful short-term goal is the experimental study of bunches with 1 ps rms length both at high ({approx_gt} 1 GeV) and low ({approx_lt} 150 MeV) electron energies. Experiments on 1 ps bunches are now feasible and can yield new insight into the high frequency impedance of storage rings and the associated phenomena which can result in bunch lengthening. Achievement of 1 ps bunches can also be expected to allow the first observation of coherent synchrotron radiation in a storage ring, in the millimeter wavelength regime. A longer-term objective is the realization of 100 fs bunches. Achievement of this goal not only will advance understanding of storage rings but will open up new opportunities in synchrotron radiation based research at both x-ray and far infrared wavelengths. It is now an appropriate time to carry forward theoretical investigations clarifying the fundamental limitations on bunch length, and to devise schemes to minimize it.

  16. Ring wormholes via duality rotations

    NASA Astrophysics Data System (ADS)

    Gibbons, Gary W.; Volkov, Mikhail S.

    2016-09-01

    We apply duality rotations and complex transformations to the Schwarzschild metric to obtain wormhole geometries with two asymptotically flat regions connected by a throat. In the simplest case these are the well-known wormholes supported by phantom scalar field. Further duality rotations remove the scalar field to yield less well known vacuum metrics of the oblate Zipoy-Voorhees-Weyl class, which describe ring wormholes. The ring encircles the wormhole throat and can have any radius, whereas its tension is always negative and should be less than -c4 / 4 G. If the tension reaches the maximal value, the geometry becomes exactly flat, but the topology remains non-trivial and corresponds to two copies of Minkowski space glued together along the disk encircled by the ring. The geodesics are straight lines, and those which traverse the ring get to the other universe. The ring therefore literally produces a hole in space. Such wormholes could perhaps be created by negative energies concentrated in toroidal volumes, for example by vacuum fluctuations.

  17. Ring Beholds a Delicate Flower

    NASA Technical Reports Server (NTRS)

    2005-01-01

    NASA's Spitzer Space Telescope finds a delicate flower in the Ring Nebula, as shown in this image. The outer shell of this planetary nebula looks surprisingly similar to the delicate petals of a camellia blossom. A planetary nebula is a shell of material ejected from a dying star. Located about 2,000 light years from Earth in the constellation Lyra, the Ring Nebula is also known as Messier Object 57 and NGC 6720. It is one of the best examples of a planetary nebula and a favorite target of amateur astronomers.

    The 'ring' is a thick cylinder of glowing gas and dust around the doomed star. As the star begins to run out of fuel, its core becomes smaller and hotter, boiling off its outer layers. The telescope's infrared array camera detected this material expelled from the withering star. Previous images of the Ring Nebula taken by visible-light telescopes usually showed just the inner glowing loop of gas around the star. The outer regions are especially prominent in this new image because Spitzer sees the infrared light from hydrogen molecules. The molecules emit infrared light because they have absorbed ultraviolet radiation from the star or have been heated by the wind from the star.

    Download the QuickTime movie for the animated version of this Ring Nebula image.

  18. Stability of the lumbar spine. A study in mechanical engineering.

    PubMed

    Bergmark, A

    1989-01-01

    From the mechanical point of view the spinal system is highly complex, containing a multitude of components, passive and active. In fact, even if the active components (the muscles) were exchanged by passive springs, the total number of elements considerably exceeds the minimum needed to maintain static equilibrium. In other words, the system is statically highly indeterminate. The particular role of the active components at static equilibrium is to enable a virtually arbitrary choice of posture, independent of the distribution and magnitude of the outer load albeit within physiological limits. Simultaneously this implies that ordinary procedures known from the analysis of mechanical systems with passive components cannot be applied. Hence the distribution of the forces over the different elements is not uniquely determined. Consequently nervous control of the force distribution over the muscles is needed, but little is known about how this achieved. This lack of knowledge implies great difficulties at numerical simulation of equilibrium states of the spinal system. These difficulties remain even if considerable reductions are made, such as the assumption that the thoracic cage behaves like a rigid body. A particularly useful point of view about the main principles of the force distributions appears to be the distinction between a local and a global system of muscles engaged in the equilibrium of the lumbar spine. The local system consists of muscles with insertion or origin (or both) at lumbar vertebrae, whereas the global system consists of muscles with origin on the pelvis and insertions on the thoracic cage. Given the posture of the lumbar spine, the force distribution over the local system appears to be essentially independent of the outer load of the body (though the force magnitudes are, of course, dependent on the magnitude of this load). Instead different distributions of the outer load on the body are met by different distributions of the forces in the

  19. Results of arthrospine assisted percutaneous technique for lumbar discectomy

    PubMed Central

    Kaushal, Mohinder

    2016-01-01

    Background: Avaialable minimal invasive arthro/endoscopic techniques are not compatible with 30 degree arthroscope which orthopedic surgeons uses in knee and shoulder arthroscopy. Minimally invasive “Arthrospine assisted percutaneous technique for lumbar discectomy” is an attempt to allow standard familiar microsurgical discectomy and decompression to be performed using 30° arthroscope used in knee and shoulder arthroscopy with conventional micro discectomy instruments. Materials and Methods: 150 patients suffering from lumbar disc herniations were operated between January 2004 and December 2012 by indiginously designed Arthrospine system and were evaluated retrospectively. In lumbar discectomy group, there were 85 males and 65 females aged between 18 and 72 years (mean, 38.4 years). The delay between onset of symptoms to surgery was between 3 months to 7 years. Levels operated upon included L1-L2 (n = 3), L2-L3 (n = 2), L3-L4 (n = 8), L4-L5 (n = 90), and L5-S1 (n = 47). Ninety patients had radiculopathy on right side and 60 on left side. There were 22 central, 88 paracentral, 12 contained, 3 extraforaminal, and 25 sequestrated herniations. Standard protocol of preoperative blood tests, x-ray LS Spine and pre operative MRI and pre anaesthetic evaluation for anaesthesia was done in all cases. Technique comprised localization of symptomatic level followed by percutaneous dilatation and insertion of a newly devised arthrospine system devise over a dilator through a 15 mm skin and fascial incision. Arthro/endoscopic discectomy was then carried out by 30° arthroscope and conventional disc surgery instruments. Results: Based on modified Macnab's criteria, of 150 patients operated for lumbar discectomy, 136 (90%) patients had excellent to good, 12 (8%) had fair, and 2 patients (1.3%) had poor results. The complications observed were discitis in 3 patients (2%), dural tear in 4 patients (2.6%), and nerve root injury in 2 patients (1.3%). About 90% patients were able

  20. Factors predicting surgical site infection after posterior lumbar surgery

    PubMed Central

    Wang, Tao; Wang, Hui; Yang, Da-Long; Jiang, Li-Qiang; Zhang, Li-Jun; Ding, Wen-Yuan

    2017-01-01

    Abstract This is a retrospective study. The purpose of this study is to explore incidence and risk factors for surgical site infection (SSI) after posterior lumbar surgery. SSI is a common complication after posterior lumbar surgery, bringing mental and physical pain and prolonging hospital stay. However, predisposing factors, as reported less, remain controversial. Patients who underwent posterior lumbar surgery at 3 centers between 2006 and 2016 were included. The possible factors include 3 aspects: demographic variables-age, sex, body mass index (BMI), waist-to-hip radio (WHR), hypertension, diabetes, heart disease, smoking, drinking, steroidal injection, surgical time between June and September, preoperative shower; blood test variables-white blood cell (WBC), neutrophil, red blood cell (RBC), hemoglobin (Hb), total protein (TP), albumin, albumin/globulin (A/G), C-reactive protein (CRP), procalcitonin (PCT), erythrocyte sedimentation rate (ESR) and surgical related variables-operation time, blood loss, operative level, instrumentation, incision length. Factors related with SSI were also performed by multivariate analysis. The prevalence of SSI was 3.00% (267 cases of 8879) had a postoperative wound infection. There were significant difference in WHR (0.92 vs 0.83), WBC (4.31 vs 6.69), TP (58.7 vs 65.2), albumin (36.9 vs 43.2), CRP (2.01 vs 0.57), PCT (0.097 vs 0.067), operation time (217.9 vs 195.7), blood loss (997.1 vs 915.3) and operative level (3.05 vs 2.45) and incision length (24.1 vs 20.0) between SSI group and non-SSI group. >60 years old, female, BMI <18.5 and >30.0, diabetes, male smoking, preoperative steroidal injection, surgical time between June and September, no preoperative shower, instrumentation surgery were risk factors for SSI after posterior lumbar surgery. Many factors, >60 years old, female, BMI, WHR, diabetes, male smoking, preoperative steroidal injection, surgical time between June and September, preoperative shower, WBC, TP, albumin

  1. Pig Lumbar Spine Anatomy and Imaging Guided Lateral Lumbar Puncture: A New Large Animal Model for Intrathecal Drug Delivery

    PubMed Central

    Pleticha, Josef; Maus, Timothy P.; Jeng-Singh, Christian; Marsh, Michael P.; Al-Saiegh, Fadi; Christner, Jodie A.; Lee, Kendall H.; Beutler, Andreas S.

    2014-01-01

    Intrathecal (IT) administration is an important route of drug delivery. Its modeling in a large animal species is a critical step. Although domestic swine is presently a preferred species in preclinical pharmacology, no proven minimally invasive method has been established to deliver agents into the pig IT space. While a “blind” lumbar puncture (LP) can sample cerebrospinal fluid (CSF), it is unreliable for drug delivery in pigs. Using computed tomography (CT) we determined the underlying anatomical reasons. The pig spinal cord was visualized terminating at the S2-S3 level. The lumbar region contained only small amounts of CSF visualized in the lateral recesses. Additional anatomical constraints identified were ossification of the midline ligaments; overlapping lamina with small interlaminar spaces; and a large bulk of epidural adipose tissue. Accommodating the pig CT anatomy, we developed an injection technique termed lateral LP (LLP) that employs advance planning of the needle path and monitoring of the IT injection progress. Key features of the LLP procedure were choosing a vertebral level without overlapping lamina or spinal ligament ossification; a needle trajectory crossing the midline; and entering the IT space in its lateral recess. Effective IT delivery was validated by injection of contrast media thereby obtaining a CT myelogram. LLP represents a safe and reliable method to deliver agents to the lumbar pig IT space, which can be implemented in a straightforward way by any laboratory with access to CT equipment and is therefore an attractive large animal model for preclinical studies of IT therapies. PMID:23518340

  2. Comparison of Posterior Lumbar Interbody Fusion and Posterolateral Lumbar Fusion in Monosegmental Vacuum Phenomenon within an Intervertebral Disc

    PubMed Central

    An, Ki-Chan; Kong, Gyu-Min; Park, Dae-Hyun; Youn, Ji-Hong; Lee, Woon-Seong

    2016-01-01

    Study Design Retrospective. Purpose To compare the clinical and radiological outcomes of posterolateral lumbar interbody fusion (PLIF) and posterolateral lumbar fusion (PLF) in monosegmental vacuum phenomenon within an intervertebral disc. Overview of Literature The vacuum phenomenon within an intervertebral disc is a serious form of degenerative disease that destabilizes the intervertebral body. Outcomes of PLIF and PLF in monosegmental vacuum phenomenon are unclear. Methods Monosegmental instrumented PLIF and PLF was performed on 84 degenerative lumbar disease patients with monosegmental vacuum phenomenon (PLIF, n=38; PLF, n=46). Minimum follow-up was 24 months. Clinical outcomes of leg and back pain were assessed using visual analogue scales for leg pain (LVAS) and back pain (BVAS), and the Oswestry disability index (ODI). The radiographic outcome was the estimated bony union rate. Results LVAS, BVAS, and ODI improved in both groups. There was no significant difference in the degree of these improvements between PLIF and PLF patients (p>0.05). Radiological union rate was 91.1% in PLIF group and 89.4% in PLF group at postoperative 24 months (p>0.05). Conclusions No significant differences in clinical results and union rates were found between PLIF and PLF patients. Selection of the operation technique will reflect the surgeon's preferences and patient condition. PMID:26949464

  3. Ring Vaccination and Smallpox Control

    PubMed Central

    van den Hof, Susan; Wallinga, Jacco; van Wijngaarden, Jan

    2004-01-01

    We present a stochastic model for the spread of smallpox after a small number of index cases are introduced into a susceptible population. The model describes a branching process for the spread of the infection and the effects of intervention measures. We discuss scenarios in which ring vaccination of direct contacts of infected persons is sufficient to contain an epidemic. Ring vaccination can be successful if infectious cases are rapidly diagnosed. However, because of the inherent stochastic nature of epidemic outbreaks, both the size and duration of contained outbreaks are highly variable. Intervention requirements depend on the basic reproduction number R0, for which different estimates exist. When faced with the decision of whether to rely on ring vaccination, the public health community should be aware that an epidemic might take time to subside even for an eventually successful intervention strategy. PMID:15200816

  4. Traversable wormholes: The Roman ring

    SciTech Connect

    Visser, M.

    1997-04-01

    In this Brief Report I introduce yet another class of geometries for which semiclassical chronology protection theorems are of dubious physical reliability. I consider a {ital {open_quotes}Roman ring{close_quotes}} of traversable wormholes, wherein a number of wormholes are arranged in a ring in such a manner that no subset of wormholes is near chronology violation, though the combined system can be arbitrarily close to chronology violation. I show that (with enough wormholes in the ring) the gravitational vacuum polarization (the expectation value of the quantum stress-energy tensor) can be made arbitrarily small. In particular, the back reaction can be kept arbitrarily small all the way to the {open_quotes}reliability horizon,{close_quotes} so that semiclassical quantum gravity becomes unreliable before the gravitational back reaction becomes large. {copyright} {ital 1997} {ital The American Physical Society}

  5. CMB lensing and giant rings

    SciTech Connect

    Rathaus, Ben; Itzhaki, Nissan E-mail: ben.rathaus@gmail.com

    2012-05-01

    We study the CMB lensing signature of a pre-inationary particle (PIP), assuming it is responsible for the giant rings anomaly that was found recently in the WMAP data. Simulating Planck-like data we find that generically the CMB lensing signal to noise ratio associated with such a PIP is quite small and it would be difficult to cross correlate the temperature giant rings with the CMB lensing signal. However, if the pre-inationary particle is also responsible for the bulk flow measured from the local large scale structure, which happens to point roughly at the same direction as the giant rings, then the CMB lensing signal to noise ratio is fairly significant.

  6. Physics of Jupiter's Gossamer Rings

    NASA Astrophysics Data System (ADS)

    Hamilton, Douglas P.; Krueger, H.

    2008-05-01

    Thebe's gossamer ring, the outermost and faintest of Jupiter's rings, extends outward by at least half a jovian radius from its source satellite while maintaining a constant vertical thickness. This structure is created by an electromagnetic perturbation known as a shadow resonance (Hamilton 2003, DPS meeting #35, #11.09). A shadow resonance arises from the abrupt shutoff of photoelectric charging when a dust particle enters Jupiter's shadow which, in turn, affects the strength of the electromagnetic perturbation from the planet's intense magnetic field. The result is a coupled oscillation between a particle's orbital eccentricity and its semimajor axis. Ring material spreads outward from Thebe while maintaining its vertical thickness just as observed by Galileo imaging. In addition to cameras, the Galileo spacecraft was also equipped with dust and plasma detectors. The spacecraft made two passes through the ring and its dust detector found that 1) dust fluxes drop immediately interior to Thebe's orbit, 2) some grains have inclinations in excess of 20 degrees and 3) submicron particles are present in the Amalthea ring in much greater numbers than in the Thebe ring. These findings can all be explained in the context of our shadow resonance model: the inner boundary is a direct consequence of the conservation of the Electromagnetic Jacobi Constant, the high inclinations are forced by a vertical version of the shadow resonance, and the excess submicron particles are a consequence of the weakening of electromagnetic forces in the vicinity of synchronous orbit. In this talk, we will present the data sets as well as detailed numerical simulations that back up these claims.

  7. Hawking radiation from black rings

    SciTech Connect

    Miyamoto, Umpei; Murata, Keiju

    2008-01-15

    We calculate the quantum radiation from the 5-dimensional charged rotating black rings by demanding the radiation eliminate the possible anomalies on the horizons. It is shown that the temperature, energy flux, and angular-momentum flux exactly coincide with those of the Hawking radiation. The black rings considered in this paper contain the Myers-Perry black hole as a limit, and the quantum radiation for this black hole, obtained in the literature, is recovered in the limit. The results support the picture that the Hawking radiation can be regarded as the anomaly eliminator on horizons and suggest its general applicability to the higher-dimensional black holes discovered recently.

  8. Regional differences in lumbar spinal posture and the influence of low back pain

    PubMed Central

    Mitchell, Tim; O'Sullivan, Peter B; Burnett, Angus F; Straker, Leon; Smith, Anne

    2008-01-01

    Background Spinal posture is commonly a focus in the assessment and clinical management of low back pain (LBP) patients. However, the link between spinal posture and LBP is not fully understood. Recent evidence suggests that considering regional, rather than total lumbar spine posture is important. The purpose of this study was to determine; if there are regional differences in habitual lumbar spine posture and movement, and if these findings are influenced by LBP. Methods One hundred and seventy female undergraduate nursing students, with and without LBP, participated in this cross-sectional study. Lower lumbar (LLx), Upper lumbar (ULx) and total lumbar (TLx) spine angles were measured using an electromagnetic tracking system in static postures and across a range of functional tasks. Results Regional differences in lumbar posture and movement were found. Mean LLx posture did not correlate with ULx posture in sitting (r = 0.036, p = 0.638), but showed a moderate inverse correlation with ULx posture in usual standing (r = -0.505, p < 0.001). Regional differences in range of motion from reference postures in sitting and standing were evident. BMI accounted for regional differences found in all sitting and some standing measures. LBP was not associated with differences in regional lumbar spine angles or range of motion, with the exception of maximal backward bending range of motion (F = 5.18, p = 0.007). Conclusion This study supports the concept of regional differences within the lumbar spine during common postures and movements. Global lumbar spine kinematics do not reflect regional lumbar spine kinematics, which has implications for interpretation of measures of spinal posture, motion and loading. BMI influenced regional lumbar posture and movement, possibly representing adaptation due to load. PMID:19014712

  9. Mini-Open Anterior Lumbar Interbody Fusion Combined with Lateral Lumbar Interbody Fusion in Corrective Surgery for Adult Spinal Deformity

    PubMed Central

    Lee, Chong-Suh; Chung, Sung-Soo; Lee, Jun-Young; Yum, Tae-Hoon; Shin, Seong-Kee

    2016-01-01

    Study Design Prospective observational study. Purpose To introduce the techniques and present the surgical outcomes of mini-open anterior lumbar interbody fusion (ALIF) at the most caudal segments of the spine combined with lateral lumbar interbody fusion (LLIF) for the correction of adult spinal deformity Overview of Literature Although LLIF is increasingly used to correct adult spinal deformity, the correction of sagittal plane deformity with LLIF alone is reportedly suboptimal. Methods Thirty-two consecutive patients with adult spinal deformity underwent LLIF combined with mini-open ALIF at the L5–S1 or L4–S1 levels followed by 2-stage posterior fixation. ALIF was performed for a mean 1.3 levels and LLIF for a mean 2.7 levels. Then, percutaneous fixation was performed in 11 patients (percutaneous group), open correction with facetectomy with or without laminectomy in 16 (open group), and additional pedicle subtraction osteotomy (PSO) in 5 (PSO group). Spinopelvic parameters were compared preoperatively and postoperatively. Hospitalization data and clinical outcomes were recorded. Results No major medical complications developed, and clinical outcomes improved postoperatively in all groups. The mean postoperative segmental lordosis was greater after ALIF (17.5°±5.5°) than after LLIF (8.1°±5.3°, p <0.001). Four patients (12.5%) had lumbar lordosis with a pelvic incidence of ±9° preoperatively, whereas this outcome was achieved postoperatively in 30 patients (93.8%). The total increase in lumbar lordosis was 14.7° in the percutaneous group, 35.3° in the open group, and 57.0° in the PSO group. The ranges of potential lumbar lordosis increase were estimated as 4°–25°, 23°–42°, and 45°–65°, respectively. Conclusions Mini-open ALIF combined with LLIF followed by posterior fixation may be a feasible technique for achieving optimal sagittal balance and reducing the necessity of more extensive surgery. PMID:27994777

  10. Osteoporosis or Low Bone Mass at the Femur Neck or Lumbar Spine in Older Adults: United States, 2005-2008

    MedlinePlus

    ... Bone Mass at the Femur Neck or Lumbar Spine in Older Adults: United States, 2005–2008 Recommend ... density at either the femur neck or lumbar spine? Nine percent of persons aged 50 years and ...

  11. Uranus' Rings: Leading up to RPX

    NASA Astrophysics Data System (ADS)

    de Pater, I.; Showalter, M.; Hammel, H.; Gibbard, S.; Lissauer, J.

    We summarize recent HST and Keck observations of the uranian ring system, taken over the past years while the viewing geometry is changing. Some highlights of our campaign to date include: i) Detection of a ring system outside of Uranus main ring system by HST (Showalter and Lissauer, Science 311, p.973, 2006), followed by color information from Keck (de Pater et al, Science 312, p.92, 2006). This system consists of two rings. The inner ring, U2, is red and relatively narrow like Saturn's G ring, while the outer ring, U1, is much broader in extent and very blue, like Saturn's E ring. Just like Enceladus is located within the E ring, moon Mab is inside U1. Saturn's E ring is most likely produced by geyser activity on Enceladus. Mab, being over 20 times smaller, is unlikely to be geologically active. However, being this small, its size is optimal to produce a ring via meteorite sputtering. ii) Detection of a ring interior to the main ring system, which might be ring 1986U2R, discovered by Voyager, though its extent and location is different from the Voyager ring. iii) Dust sheets in between the main ring. These may be similar to the dust sheets seen by Voyager in forward scattered light, yet our observations indicate large changes from the Voyager era iv) New moons were detected by HST. The orbits of some of these moons appear to be somewhat erratic. The color of moon Mab appears to be more similar to that of the large outer moons than the small inner moons. Earth will cross Uranus' ring plane three times in 2007-2008 (2 May, 16 Aug. 2007, 20 Feb. 2008), and the Sun will cross it once (7 Dec. 2007). At these times optically thin dusty rings will brighten considerably, making this period an ideal time to study Uranus' outer ring system. Between the May and August crossings, as well as between December and February, the Earth and Sun are on opposite sides of the rings, so that any optically thick rings will essentially be invisible. This allows phenomena normally

  12. Conical O-ring seal

    DOEpatents

    Chalfant, Jr., Gordon G.

    1984-01-01

    A shipping container for radioactive or other hazardous materials which has a conical-shaped closure containing grooves in the conical surface thereof and an O-ring seal incorporated in each of such grooves. The closure and seal provide a much stronger, tighter and compact containment than with a conventional flanged joint.

  13. Baroclinic Structure of Oceanic Rings

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Sun, C.

    One of the most important analytical solutions to the two dimensional incompressible flow is circular Rankin vortex that has a solid-body core and an approximately irrotational far field. For an f-plane rotating flow, Ingersoll (1969) presented a closed-form ring solution superposed with a zonal flow. So far most studies have been concerned with two dimensional and barotropic situations.

  14. On the vortex ring state

    NASA Astrophysics Data System (ADS)

    Green, Richard; Gillies, E.; Giuni, M.; Hislop, J.; Savas, Omer

    2014-11-01

    The investigation considers the vortex ring state, a phenomenon normally associated with the collapse of a trailing, helical vortex wake into a unstable vortex ring, and is a problem encountered when a helicopter rotor descends into its own wake. A series of wind tunnel and towing tank experiments on rotor systems have been performed, and a comparison is then made with the behaviour of a specially designed open core, annular jet system that generates a mean flow velocity profile similar to that observed below a rotor. In experimentally simulated descents the jet system forms flow patterns that are topologically similar to the vortex ring state of a rotor system. Furthermore the dynamic behaviour of the flow shares many of the important characteristics of the rotor flow. This result suggests that the phenomenon of the vortex ring state of a rotor wake is decoupled from the detailed vortex dynamics of the helical vortex filaments themselves. The presentation will describe the principle behind the investigation, the details of the annular jet system and the results gained using PIV and flow visualisation of the wake and jet systems.

  15. Conical O-ring seal

    DOEpatents

    Chalfant, G.G. Jr.

    A shipping container for radioactive or other hazardous materials has a conical-shaped closure containing grooves in the conical surface thereof and an O-ring seal incorporated in each of such grooves. The closure and seal provide a much stronger, tighter and compact containment than with a conventional flanged joint.

  16. Stirring properties of vortex rings

    NASA Astrophysics Data System (ADS)

    Auerbach, David

    1991-05-01

    Ring vortex evolution, from the initial roll-up phase through to the final turbulent phase, was experimentally studied to see the dependence of its stirring properties on both the initial (accelerating, constant, decelerating, slow, fast) piston motion as well as on the boundary (tube/hole geometry) conditions. Stirring between fluid initially upstream and that initially downstream of the nozzle plane is done more by convective entrainment at the beginning (roll-up and contraction phases), by diffusive entrainment during the laminar and wavy phases, and by mixed entrainment and ejection during the transition to turbulence and the turbulent phase itself. During vortex roll-up, it was found that tubes eject shorter streaklines than do holes, and that there is less Re dependence for this for tubes than for holes. During the contraction phase, entrainment ends, save for minimal entrainment due to axial inflow into the ring from along the cores of Goertler-type vortices. Generally, the rate of fluid ejected is largest during the transition from the wavy to the turbulent state. As far as the stability of the vortices is concerned, rings generated at holes are less stable than those generated at tubes. During the final turbulent phase, rings not only entrain fluid but eject it periodically into the wake: Between two and four hairpin vortices are generated and laid off in the wake during each ejection. The frequency at which such ejections takes place scales as a Strouhal number that takes on values of between 2 and 4.

  17. Looking for rings and things

    NASA Astrophysics Data System (ADS)

    Kenworthy, Matthew

    2017-04-01

    It's not often that an astronomical object gets its own dedicated observatory, but as the planet Beta Pictoris b moves in front of its host star, its every move will be watched by bRing, eager to discover more about the planet's Hill sphere, explains Matthew Kenworthy.

  18. Cavity-locked ring down spectroscopy

    DOEpatents

    Zare, Richard N.; Paldus, Barbara A.; Harb, Charles C.; Spence, Thomas

    2000-01-01

    Distinct locking and sampling light beams are used in a cavity ring-down spectroscopy (CRDS) system to perform multiple ring-down measurements while the laser and ring-down cavity are continuously locked. The sampling and locking light beams have different frequencies, to ensure that the sampling and locking light are decoupled within the cavity. Preferably, the ring-down cavity is ring-shaped, the sampling light is s-polarized, and the locking light is p-polarized. Transmitted sampling light is used for ring-down measurements, while reflected locking light is used for locking in a Pound-Drever scheme.

  19. The formation of Jupiter's faint rings

    PubMed

    Burns; Showalter; Hamilton; Nicholson; de Pater I; Ockert-Bell; Thomas

    1999-05-14

    Observations by the Galileo spacecraft and the Keck telescope showed that Jupiter's outermost (gossamer) ring is actually two rings circumscribed by the orbits of the small satellites Amalthea and Thebe. The gossamer rings' unique morphology-especially the rectangular end profiles at the satellite's orbit and the enhanced intensities along the top and bottom edges of the rings-can be explained by collisional ejecta lost from the inclined satellites. The ejecta evolves inward under Poynting-Robertson drag. This mechanism may also explain the origin of Jupiter's main ring and suggests that faint rings may accompany all small inner satellites of the other jovian planets.

  20. High-Speed Ring Bus

    NASA Technical Reports Server (NTRS)

    Wysocky, Terry; Kopf, Edward, Jr.; Katanyoutananti, Sunant; Steiner, Carl; Balian, Harry

    2010-01-01

    The high-speed ring bus at the Jet Propulsion Laboratory (JPL) allows for future growth trends in spacecraft seen with future scientific missions. This innovation constitutes an enhancement of the 1393 bus as documented in the Institute of Electrical and Electronics Engineers (IEEE) 1393-1999 standard for a spaceborne fiber-optic data bus. It allows for high-bandwidth and time synchronization of all nodes on the ring. The JPL ring bus allows for interconnection of active units with autonomous operation and increased fault handling at high bandwidths. It minimizes the flight software interface with an intelligent physical layer design that has few states to manage as well as simplified testability. The design will soon be documented in the AS-1393 standard (Serial Hi-Rel Ring Network for Aerospace Applications). The framework is designed for "Class A" spacecraft operation and provides redundant data paths. It is based on "fault containment regions" and "redundant functional regions (RFR)" and has a method for allocating cables that completely supports the redundancy in spacecraft design, allowing for a complete RFR to fail. This design reduces the mass of the bus by incorporating both the Control Unit and the Data Unit in the same hardware. The standard uses ATM (asynchronous transfer mode) packets, standardized by ITU-T, ANSI, ETSI, and the ATM Forum. The IEEE-1393 standard uses the UNI form of the packet and provides no protection for the data portion of the cell. The JPL design adds optional formatting to this data portion. This design extends fault protection beyond that of the interconnect. This includes adding protection to the data portion that is contained within the Bus Interface Units (BIUs) and by adding to the signal interface between the Data Host and the JPL 1393 Ring Bus. Data transfer on the ring bus does not involve a master or initiator. Following bus protocol, any BIU may transmit data on the ring whenever it has data received from its host. There

  1. F Ring Mini-Jets

    NASA Astrophysics Data System (ADS)

    Attree, N.; Murray, C.; Cooper, N. J.; Williams, G.

    2012-12-01

    Mini-jets are small, (~50 km) linear features observed in Cassini images to be emanating from Saturn's F ring; they are believed to be produced by collisions with a local population of moonlets. An analysis of one such feature, observed over the course of a ~7.5 h sequence as its length changed from ~75 km to ~250 km while it simultaneously appeared to collapse back into the core, supports the collisional theory of their origin [1]. Orbit determination suggests that this mini-jet consisted of ring material displaced by a ~1 m/s collision with a nearby object, resulting in paths relative to the core that are due to a combination of keplerian shear and epicyclic motion. The colliding object itself is likely to be too small to resolve in these images but represents just one member of a population of F ring moonlets. Such a population has been investigated by UVIS occultations [2], and other methods, but generally remains unresolved in Cassini images. Collisional features such as this mini-jet therefore provide an additional tracer for the region's moonlet population. In this talk we will present the results of recent work in measuring and describing a subset of ~350 catalogued mini-jets, applying knowledge gained from the original mini-jet feature. Their distribution in space and time, proximity to Prometheus and evolution are all examined in an effort to place constraints on the properties of the underlying population of colliding objects. References [1] N. O. Attree, C. D. Murray, N. J. Cooper, and G. A. Williams. Detection of low velocity collisions in Saturn's F ring. Ap. J. Lett. (In press). [1] B. K. Meinke, L. W. Esposito, N. Albers, and M. Sremevi. Classification of F ring features observed in cassini UVIS occultations. Icarus, 218(1):545 - 554, 2012.

  2. Three-dimensional lumbar segment movement characteristics during paediatric cerebral palsy gait.

    PubMed

    Kiernan, D; Malone, A; O'Brien, T; Simms, C K

    2017-03-01

    Kinematic analysis of the trunk during cerebral palsy (CP) gait has been well described. In contrast, movement of the lumbar spine is generally ignored. This is most likely due to the complex nature of the spine. As an alternative to using complex sensor protocols, this study modelled the lumbar region as a single segment and investigated characteristic patterns of movement during CP gait. In addition, the impact of functional level of impairment and the relationship with lower lumbar spinal loading were examined. Fifty-two children with CP (26 GMFCS I and 26 GMFCS II) and 26 controls were recruited. A full barefoot 3-dimensional kinematic and kinetic analysis were conducted. Lumbar segment movement demonstrated increased forward flexion for CP children. This movement became more pronounced according to GMFCS level with GMFCS II children demonstrating increases of up to 8°. In addition, a moderate correlation was present between lumbar flexion/extension and L5/S1 sagittal moments (r=0.427 in the global frame and r=0.448 with respect to the pelvis, p<0.01). Children with CP demonstrated increased movement of the lumbar region compared to TD, with movement becoming more excessive as GMFCS level increased. Excessive forward flexion and loading at the lumbar spine were linked. However, the moderate correlation suggests other contributors to increased loading were present. In conclusion, this study is a first step at identifying how lumbar segment movement is altered during CP gait.

  3. Remote cerebellar hemorrhage as an early and potentially lethal complication of a discal lumbar herniation surgery.

    PubMed

    Royon, V; Rabehenoina, C; Tourrel, F; Compère, V; Dureuil, B

    2014-01-01

    Remote cerebellar hemorrhage (RCH) is an infrequent but serious complication after lumbar herniation surgery. Little is known about this complication but excessive cerebrospinal fluid (CSF) leakage is thought to be a leading cause of RCH. We describe the case of a patient suffering from a life-threatening RCH, which occurred a few hours after lumbar disc herniation surgery.

  4. Evidence-based practice guidelines for the diagnosis and treatment of lumbar spinal conditions.

    PubMed

    Metzger, Robert L

    2016-12-16

    Low back pain remains one of the most common patient complaints. It can exist alone or with the presence of lower extremity symptoms. Review of evidence-based guidelines will assist primary care providers in the identification and treatment of various lumbar disorders in addition to ruling out specific lumbar spinal pathologies.

  5. Diabetes Mellitus, a New Risk Factor for Lumbar Spinal Stenosis: A Case–Control Study

    PubMed Central

    Asadian, Leila; Haddadi, Kaveh; Aarabi, Mohsen; Zare, Amirhossein

    2016-01-01

    OBJECTIVES This study aimed to determine the prevalence of diabetes mellitus in patients with spinal stenosis and lumbar vertebral disk degeneration, and the correlation of diabetes with these diseases. STUDY DESIGN This is a cross-sectional study. METHODS This case–control study was performed during 2012–2014 with 110 patients suffering from lumbar spinal stenosis and 110 patients with lumbar disk herniation, who were diagnosed using clinical and radiological evidences. Additionally, 110 participants who were referred to the clinic and did not show clinical signs of degenerative diseases of the lumbar spine entered the study as a control group. Demographic data and medical histories of the patients were collected using checklists. RESULTS A total of 50 patients (15.2%) were diagnosed with diabetes, which comprised 32 (29.1%) in the stenosis group, 7 (6.4%) in the lumbar disk herniation group, and 11 (10%) in the control group. The prevalence of diabetes in women with spinal stenosis and women with lumbar disk herniation was 35.9% and 10.3%, respectively, whereas prevalence of diabetes in women was 10.9% in the control group. This difference was statistically significant in the spinal stenosis group in comparison with the controls (P < 0.0001). Conversely, no significant difference was found in men. CONCLUSIONS There is an association between diabetes and lumbar spinal stenosis. Diabetes mellitus may be a predisposing factor for the development of lumbar spinal stenosis. PMID:27168730

  6. The role of lumbar disc replacement in the surgical management of low back pain.

    PubMed

    Freeman, Brian J C

    2012-01-01

    Spinal fusion has long been the standard surgical treatment for degenerative disorders of the spine, but clinical outcomes are often unpredictable. Lumbar disc replacement allows removal of the pain source while preserving motion. This article explores the role of lumbar disc replacement in the surgical management of low back pain.

  7. Effects of hip exercises for chronic low-back pain patients with lumbar instability

    PubMed Central

    Lee, Sang wk; Kim, Suhn Yeop

    2015-01-01

    [Purpose] The purpose of this study was to compare hip range of motion between a lumbar stability group and a lumbar instability group, and to evaluate the effectiveness of hip exercises for low-back pain patients with lumbar instability. [Subjects] Seventy-eight patients with chronic low-back pain were the subjects. [Methods] The patients were divided into two groups: a lumbar stability group (n=45) and a lumbar instability group (n=33). They were assessed using the Korean version of the Oswestry Disability Index (KODI) to determine the level of disability of the patients with low-back pain. A 100 mm visual analog scale (VAS) was used to assess low-back pain. [Results] The limitation of hip range of motion of the lumbar instability group was significantly greater than that of the lumbar stability group. Comparisons among four groups at three weeks and six weeks after the start of hip exercises revealed that the VAS score of each group had significantly decreased. Comparisons among four groups at three weeks and at six weeks after the start of hip exercises revealed that the KODI score of each group had significantly decreased. [Conclusion] These findings suggest that the performance of hip exercises by chronic low-back pain patients with lumbar instability is more effective than conventional therapy at reducing low-back pain and levels of disability. PMID:25729164

  8. Comparison of chronic low-back pain patients hip range of motion with lumbar instability

    PubMed Central

    Lee, Sang wk; Kim, Suhn Yeop

    2015-01-01

    [Purpose] The purpose of this study was to compare differences in hip range of motion between a lumbar stability group and a lumbar instability group of patients with chronic low-back pain. [Subjects] Sixty-nine patients with chronic low-back pain were divided into two groups: a lumbar stability group (n=39) and a lumbar instability group (n=30). [Methods] The patients were assessed using a goniometer to evaluate the hip range of motion at pre-test. Data were analyzed using SPSS 18.0 software for Windows. The experimental data were analyzed using one-way ANOVA, repeated one-way ANOVA, and the t-test, and a significance level of 0.05. [Results] The limitation of hip range of motion of the lumbar instability group was significantly greater than that of the lumbar stability group. [Conclusion] The chronic low-back pain patients showed greater limitation of hip range of motion than healthy persons, and among them, those who had lumbar instability showed greater limitation than those with lumbar stability. PMID:25729165

  9. Inferior Lumbar Triangle Hernia as a Rarely Report Cause of Low Back Pain: A Report of 4 Cases

    DTIC Science & Technology

    2010-01-01

    to overlook a lumbar hernia may be lumbago, lumbar radicular syndrome, or lumbar somatic dysfunction . This prob- lem will not have radicular signs or...detect defects between muscular and fascial layers, visualize herniated viscera, and differentiate a hernia from renal and other soft-tissue tumors is one

  10. Evaluation of the Etoricoxib-Mediated Pain-Relieving Effect in Patients Undergoing Lumbar Fusion Procedures for Degenerative Lumbar Scoliosis: A Prospective Randomized, Double-Blind Controlled Study.

    PubMed

    Shi, Yongxiang; Wang, Ping; Hu, Xinlei; Ye, Zhaoming

    2015-04-01

    This randomized, double-blind study was carried out to evaluate the effectiveness of etoricoxib in controlling the pain during lumbar fusion surgery of the degenerative lumbar scoliosis patients. We found that perioperative use of etoricoxib produced a significant reduction in the degree of pain compared to the patients treated with placebo. Etoricoxib eased the pain and helped to manage the discomfort of lumbar fusion surgery. In addition, etoricoxib was well tolerated as it caused no serious adverse reaction, suggesting a safe profile. Etoricoxib also appeared to ensure and promote the positive effect of surgery, however, insignificantly. Thus, the results suggest that etoricoxib was effective in safely managing the pain during the lumbar fusion surgery and recovery thereafter.

  11. Degenerative disease in lumbar spine of military parachuting instructors.

    PubMed

    Bar-Dayan, Y; Weisbort, M; Bar-Dayan, Y; Velan, G J; Ravid, M; Hendel, D; Shemer, J

    2003-12-01

    Parachuting, be it static line or skydiving, places enormous stresses on the human spine. It is, therefore, important to determine the prevalence and severity of degenerative changes in the lumbar spine of subjects who practice this sport activity. Seventy four parachuting instructors, mean age 33 years and with an average of 410 static line and skydiving jumps, were included in the study. Past radiographs were examined and compared to current anterolateral and lateral views of the lumbar spine, in order to determine the prevalence of degenerative changes and document possible progression. Doubtful radiographic changes in the lumbar spine were identified in 47.4 percent of the parachuting instructors, mild degeneration in 9.6 percent, moderate degenerative disease in 10.9 percent and severe radiographic changes in 5.5 percent. Schmorll nodes were found in 8.1 percent of the subjects. Traction spurs--osteophytes were identified in 6.8 percent. The degenerative changes correlated with age and the number of jumps. Spondylolysis of L5-S1 and L3-L4 segments were observed in 12.2 and 1.4 percent respectively. Progressive spondylolisthesis was found in 2 subjects. No correlation was found between the severity of radiographic changes and either the prevalence and the severity of low back pain. The present findings provide a rational for considering repeated sheer stress as an etiology of degenerative changes in the spinal cord, and as a possible contributing factor to the pathogenesis of spondylolysis. Further study has to be done comparing parachuting instructors to a non-parachuting group, or equivalent physically active individuals, in order to assess the effect of sport-background on the development of degenerative changes.

  12. Prevalence of Symptomatic Lumbar Spondylolysis in Pediatric Patients.

    PubMed

    Nitta, Akihiro; Sakai, Toshinori; Goda, Yuichiro; Takata, Yoichiro; Higashino, Kosaku; Sakamaki, Tadanori; Sairyo, Koichi

    2016-05-01

    Lumbar spondylolysis, a stress fracture of the pars interarticularis, is prevalent in adolescent athletes. Recent advances in diagnostic tools and techniques enable early diagnosis before these fractures progress to complete fractures through the pars. However, because patients often consult family physicians for primary care of low back pain and these physicians may not have access to diagnostic modalities such as magnetic resonance imaging (MRI) and computed tomography, stress fractures can be missed. This study surveyed the prevalence of symptomatic spondylolysis in pediatric patients who consulted an orthopedic clinic for primary care and investigated whether such acute stress fractures may be overlooked without MRI. The prospective study investigated 264 patients who were younger than 19 years and had low back pain. Of the 153 patients (58.0%) with low back pain persisting for longer than 2 weeks, 136 who agreed to undergo MRI were included in the study. This group included 11 elementary school students, 71 junior high school students, and 54 high school students. The overall prevalence of lumbar spondylolysis was 39.7% (54 of 136) and was 9.3% in elementary school students (5 of 11, 45.5%), 59.3% in junior high school students (32 of 71, 45.1%), and 31.5% in high school students (17 of 54, 31.5%). All 54 patients with spondylolysis had a history of athletic activity. Primary care physicians should recognize that approximately 40% of pediatric patients presenting with low back pain persisting for longer than 2 weeks may have spondylolysis and should consider MRI in those with a history of athletic activity. Because the spine is immature in this age group, almost half of affected elementary school and junior high school students may have lumbar spondylolysis. [Orthopedics. 2016; 39(3):e434-e437.].

  13. Does pregnancy increase the efficacy of lumbar epidural anesthesia?

    PubMed

    Arakawa, M

    2004-04-01

    Pregnancy has been reported to enhance the sensitivity of nerves to local anesthetics and to decrease anesthetic requirements during regional anesthesia. In this study, whether pregnancy increased the efficacy of lumbar epidural anesthesia was evaluated. Two populations (14 pregnant and 14 non-pregnant women) undergoing lumbar epidural anesthesia were studied and received 17 mL of 2% lidocaine-epinephrine (1: 200,000). The pain threshold response after repeated electrical stimulation was used to assess sensory blockade at the L2, S1 and S3 dermatomes. Motor blockade was evaluated using the Bromage score. Demographic data except for weight were comparable between the two groups. There was a significant difference in cephalad spread of anesthesia between the groups. No significant differences in pain threshold or onset of sensory blockade at the L2, S1 or S3 segments were found between the groups. The pain thresholds at the S1 and S3 dermatomes were significantly lower than that at L2 within each group. The mean onset times at the S1 and S3 dermatomes were significantly longer than that at L2 within each group. No differences in Bromage score were found between the groups. In pregnant women, cephalad spread of epidural anesthesia was facilitated but latency of blockade, density and motor blockade were not. It takes over 25 min to achieve satisfactory blockade at sacral segments. Those who perform lumbar epidural anesthesia alone for cesarean section should consider the use of additives (e.g. fentanyl, bicarbonate) to enhance the block, or a greater volume of local anesthetic.

  14. [Comparative studies of patient positioning for lumbar intervertebral disk operation].

    PubMed

    Rudolph, Ch; Schaffranietz, L; Hellmundt, L; Vitzthum, H E; Olthoff, D

    2002-01-01

    For surgery on lumbar disks by the posterior route, patients are placed either on a Wilson frame or in genupectoral position. The aim of the prospective study was to record and describe the haemodynamic changes resulting from the patients' position. After written informed consent had been received, 80 neurosurgical patients undergoing lumbar disk surgery were randomly divided into two groups; group I--Wilson frame, group II--genupectoral position. In each group, 20 patients received total intravenous anaesthesia (Alfentanil or Remifentanil, Propofol) and 20 balanced anaesthesia with Isoflurane and Alfentanil or Remifentanil. Haemodynamic parameters (mean arterial pressure--MAP and heart rate--HR) were recorded automatically at three measuring times (MT): firstly, after induction of anaesthesia; secondly, before re-direction; thirdly, after re-direction on the Wilson frame or in the genupectoral position. Induction of anaesthesia did not lead to a significant decrease in MAP (MT 1: 92.5 +/- 15.2 mmHg, MT 2: 89 +/- 13.4 mmHg, n = 80). In group I (n = 40), no significant changes were observed in MAP and HR at MT 3 (p = 0.882, p = 0.051). In comparison to group I, the genupectoral position was associated with significant drops in MAP and HR. The genupectoral position caused a significant decrease in MAP (p < 0.001) and HR (p = 0.016) at MT 3. Our data suggest that body weight or body mass index do not necessarily lead to a preference for one of the two possible positions of the patient. Complications resulting from haemodynamic changes were not seen in either group. We recommend the Wilson frame for neurosurgical lumbar disk surgery in cases of cardiovascular or cerebrovascular disorders. The adaptive capacities in the genupectoral position as a result of the modifying distribution of blood volume are limited in these patients. Furthermore, the dose-dependent effects of different anaesthetics on haemodynamic parameters in these prone positions should be explored.

  15. Midline lumbar fusion using cortical bone trajectory screws. Preliminary report

    PubMed Central

    Bielecki, Mateusz; Prokopienko, Marek; Nowak, Arkadiusz; Czernicki, Tomasz; Marchel, Andrzej

    2016-01-01

    Introduction Midline lumbar fusion (MIDLF) using cortical bone trajectory is an alternative method of transpedicular spinal fusion for degenerative disease. The new entry points’ location and screwdriving direction allow the approach-related morbidity to be reduced. Aim To present our preliminary experience with the MIDLF technique on the first 5 patients with lumbar degenerative disease and with follow-up of at least 6 months. Material and methods Retrospective analysis was performed on the first 5 patients with foraminal (4) or central (1) stenosis operated on between December 2014 and February 2015. Three patients were fused at L4–L5 and two at the L5–S1 level. Results No intra- or post-operative complications occurred with this approach. An improvement regarding the leading symptom in the early postoperative period (sciatica 4/4, claudication 1/1) was achieved in all patients. The mean improvements in the visual analogue scale for low back and leg pain were 2.2 and 4.8 respectively. The mean Oswestry Disability Index scores were 52% (range: 16–82%) before surgery and 33% (range: 12–56%) at 3-month follow-up (mean improvement 19%). At the most recent follow-up, 4 patients reported the maintenance of the satisfactory result. The early standing and follow-up X-rays showed satisfactory screw placement in all patients. Conclusions In our initial experience, the MIDLF technique seems to be an encouraging alternative to traditional transpedicular trajectory screws when short level lumbar fusion is needed. Nevertheless, longer observations on larger groups of patients are needed to reliably evaluate the safety of the method and the sustainability of the results. PMID:27829938

  16. Evaluation of the influence of pedicle-lengthening osteotomy on lumbar stability

    PubMed Central

    Gao, Maofeng; Zou, Jun; Zhang, Zhigang; Luo, Zongping; Yang, Huilin

    2016-01-01

    Pedicle-lengthening osteotomy (PLO) is a minimally invasive and effective surgical procedure for lumbar spinal stenosis syndrome. Compared with traditional surgery, PLO can effectively enlarge the spinal canal while minimizing the disruption of posterior anatomical structures of the lumbar vertebra, leading to reduced postoperative perineural scarring adhesion and good clinical outcomes using minimally invasive procedures. However, PLO is still in its early stages, and only a few relevant experimental and clinical studies have been reported. The present study was performed to investigate the influence of PLO on the stability of lumbar vertebrae. The results indicated that PLO can effectively enlarge the spinal canal, and no lumbar spondylolisthesis or other complications occurred in this study. Moreover, this procedure does not significantly affect the stability of the lumbar spine, suggesting a possible clinical application. PMID:27347315

  17. Conservative management of recurrent lumbar disk herniation with epidural fibrosis: a case report

    PubMed Central

    Welk, Aaron B.; Werdehausen, Destiny N.; Kettner, Norman W.

    2012-01-01

    Objective A retrospective case report of a 24-year-old man with recurrent lumbar disk herniation and epidural fibrosis is presented. Recurrent lumbar disk herniation and epidural fibrosis are common complications following lumbar diskectomy. Clinical Features A 24-year-old patient had a history of lumbar diskectomy and new onset of low back pain and radiculopathy. Magnetic resonance imaging revealed recurrent herniation at L5/S1, left nerve root displacement, and epidural fibrosis. Intervention and Outcomes The patient received a course of chiropractic care including lumbar spinal manipulation and rehabilitation exercises with documented subjective and objective functional and symptomatic improvement. Conclusion This case report describes chiropractic management including spinal manipulative therapy and rehabilitation exercises and subsequent objective and subjective functional and symptomatic improvement. PMID:23843756

  18. The Canarias Einstein ring: a newly discovered optical Einstein ring

    NASA Astrophysics Data System (ADS)

    Bettinelli, M.; Simioni, M.; Aparicio, A.; Hidalgo, S. L.; Cassisi, S.; Walker, A. R.; Piotto, G.; Valdes, F.

    2016-09-01

    We report the discovery of an optical Einstein ring in the Sculptor constellation, IAC J010127-334319, in the vicinity of the Sculptor dwarf spheroidal galaxy. It is an almost complete ring (˜300°) with a diameter of ˜4.5 arcsec. The discovery was made serendipitously from inspecting Dark Energy Camera (DECam) archive imaging data. Confirmation of the object nature has been obtained by deriving spectroscopic redshifts for both components, lens and source, from observations at the 10.4 m Gran Telescopio CANARIAS (GTC) with the spectrograph OSIRIS. The lens, a massive early-type galaxy, has a redshift of z = 0.581, while the source is a starburst galaxy with redshift of z = 1.165. The total enclosed mass that produces the lensing effect has been estimated to be Mtot = (1.86 ± 0.23) × 1012 M⊙.

  19. The management of pain following laminectomy for lumbar disc lesions.

    PubMed Central

    Martin, G.

    1981-01-01

    Assessment of the results of laminectomy for lumbar disc lesions is unsatisfactory, but it seems that some degree of recurrent pain is virtually inevitable. The clinical features and incidence of the various painful syndromes seen in these patients, including one, the sacro-spinalis insertion syndrome, which has not previously been described, are outlined and the management of each is discussed with reference to two personal series, one of 98 patients consecutively undergoing laminectomy and the other of 35 patients referred because of recurrent pain following laminectomy. Finally, problems of prophylaxis are considered. PMID:6454375

  20. Management of Plantar Hyperhidrosis with Endoscopic Lumbar Sympathectomy.

    PubMed

    Rieger, Roman

    2016-11-01

    Primary plantar hyperhidrosis is defined as excessive secretion of the sweat glands of the feet and may lead to significant limitations in private and professional lifestyle and reduction of health-related quality of life. Conservative therapy measures usually fail to provide sufficient relieve of symptoms and do not allow long-lasting elimination of hyperhidrosis. Endoscopic lumbar sympathectomy appears to be a safe and effective procedure for eliminating excessive sweating of the feet and improves quality of life of patients with severe plantar hyperhidrosis.

  1. Post-lumbar puncture arachnoiditis. The need for directed questioning.

    PubMed

    Etchepare, Fabien; Roche, Bruno; Rozenberg, Sylvie; Dion, Elisabeth; Bourgeois, Pierre; Fautrel, Bruno

    2005-03-01

    The inflammation of the arachnoid mater may produce a fibrinous exudate around the roots that causes them to adhere to the dural sheath. We report the case of a man aged 23 years who suffered from acute inflammatory truncated sciatica. The diagnosis of adhesive arachnoiditis was made in front of clinical arguments associated to typical signs on Myelo CT Scan and MRI. The only explanation ever found was a traumatic lumbar puncture at the age of 6 years for suspected meningitis. Sequelae of arachnoiditis are difficult to diagnosis. When MRI or myelography suggests it as a possibility, precise directed questioning is necessary to seek a history, albeit distant, of spinal or meningeal events.

  2. Dumb-bell-type teratoma in the lumbar spine.

    PubMed

    Okuyama, K; Abe, E; Hoshi, N; Misawa, A; Tamura, Y; Chiba, M

    2000-02-01

    We report a case of a lumbar teratoma in a 50-year-old woman. The teratoma showed a dumb-bell-type expansion at the level of the left L3/4 foramen with massive erosion of the L3 vertebral body. MRI revealed inhomogeneous signal changes in the tumor, which were histologically compatible with a mixture of bone, muscle, fat, and cyst containing sebaceous material. Complete resection of the tumor and spinal arthrodesis with pedicle screw fixation was necessary to obtain stability of the affected spinal segment.

  3. Lumbar spine surgery positioning complications: a systematic review.

    PubMed

    Shriver, Michael F; Zeer, Valerie; Alentado, Vincent J; Mroz, Thomas E; Benzel, Edward C; Steinmetz, Michael P

    2015-10-01

    OBJECT There are a variety of surgical positions that provide optimal exposure of the dorsal lumbar spine. These include the prone, kneeling, knee-chest, knee-elbow, and lateral decubitus positions. All are positions that facilitate exposure of the spine. Each position, however, is associated with an array of unique complications that result from excessive pressure applied to the torso or extremities. The authors reviewed clinical studies reporting complications that arose from positioning of the patient during dorsal exposures of the lumbar spine. METHODS MEDLINE, Scopus, and Web of Science database searches were performed to find clinical studies reporting complications associated with positioning during lumbar spine surgery. For articles meeting inclusion criteria, the following information was obtained: publication year, study design, sample size, age, operative time, type of surgery, surgical position, frame or table type, complications associated with positioning, time to first observed complication, long-term outcomes, and evidence-based recommendations for complication avoidance. RESULTS Of 3898 articles retrieved from MEDLINE, Scopus, and Web of Science, 34 met inclusion criteria. Twenty-four studies reported complications associated with use of the prone position, and 7 studies investigated complications after knee-chest positioning. Complications associated with the knee-elbow, lateral decubitus, and supine positions were each reported by a single study. Vision loss was the most commonly reported complication for both prone and knee-chest positioning. Several other complications were reported, including conjunctival swelling, Ischemic orbital compartment syndrome, nerve palsies, thromboembolic complications, pressure sores, lower extremity compartment syndrome, and shoulder dislocation, highlighting the assortment of possible complications following different surgical positions. For prone-position studies, there was a relationship between increased

  4. Multisegmental pneumatocysts of the lumbar spine mimic osteolytic lesions.

    PubMed

    Steingruber, I E; Bach, C M; Wimmer, C; Nogler, M; Buchberger, W

    2001-01-01

    Circumscribed radiolucencies within the vertebral bones can be due to a variety of changes including benign and malignant tumours or tumour-like lesions. Radiolucencies due to degenerative intraosseous pneumatocyst are very uncommon but have to be taken into the differential diagnosis in well-circumscribed lytic lesions of the vertebral bodies. We describe the first case of multisegmental pneumatocysts in the lumbar spine mimicking osteolytic lesions. On computed tomography, the air-equivalent attenuation values of the lesions and the close vicinity to the degenerated vertebral endplates with vacuum phenomenon led to the correct diagnosis.

  5. [A case of paravertebral lumbar meningomyelocele (author's transl)].

    PubMed

    Kishihara, T; Nakagawa, Y; Kaneko, S; Saitoh, H

    1976-11-01

    A case reported here is one year-old girl, who was admitted to our neurosurgical service because of gradually increasing swelling in the left lumbar region, and maldevelopment and paresis of the left leg since birth. From the level of L-2 to S-1, there was a 8 X 7 xm subcutaneous swelling of lipomatous consistency with well-defined margins. Of particular characteristics was that the swelling didn't cross the midline and was entirely located in the left paravertebral region (Fig. 1). In the spine no gap could be felt between the spinous processes. There was no evidence of hydrocephalus, but she bad marked right sided scoliotic deformity of the lumbar region, and dislocation of hip joint and club-foot on the left side. Rectum-bladder-vaginal fistula with defect of anus and hypoplasia of kidney on the left side were also detected. Skiagram of the lumbosacral spine revealed marked right-sided scoliosis at the level of L-1 and hypoplasia of left pedicles, accompanied with marked dilation of transverse diameter of spinal canal between the level of L-1 to S-2. Defect of laminae of lumbosacral spine was not definately determined. Conray myelogram showed presence of cyst protruding laterally to the left paravertebral region probably through defect of lamina on the left side at the level of L-5 (Fig 2). At operation, it was confirmed that meningomyelocele protruded out laterally through the defect of half of lamina at the level of L-5. Massive lipoma was noted inside as well as outside the dura mater. Neural elements were replaced inside the spinal canal and the dura repaired. The postoperative period was uneventful. Diagram of defect of lamina at the level of L-5 and its relationships to the meningomyelocele sac is shown in Fig. 3. Meningocele or meningomyelocele which lays in the paravertebral lumbar region is very rare (Table 2), but the possibility of this disease should always be considered when we examine the patients with lipomatous or cystic swelling in the

  6. Rapidly Progressive Gas-containing Lumbar Spinal Epidural Abscess

    PubMed Central

    Bang, Jin Hyuk

    2015-01-01

    Gas-containing (emphysematous) infections of the abdomen, pelvis, and extremities are well-known disease entities, which can potentially be life-threatening. They require aggressive medical and often surgical treatment. In the neurosurgical field, some cases of gas-containing brain abscess and subdural empyema have been reported. Sometimes they progress rapidly and even can cause fatal outcome. However, gas-containing spinal epidural abscess has been rarely reported and clinical course is unknown. We report on a case of rapidly progressive gas-containing lumbar spinal epidural abscess due to Enterococcus faecalis in a 72-year-old male patient with diabetes mellitus. PMID:26512268

  7. Pyogenic Intradural Abscess of Lumbar Spine: A Case Report

    PubMed Central

    Cheon, Jeong-Eun; Chung, You-Nam; Park, Sung Bae

    2015-01-01

    We report a case of spinal intradural abscess which shows serial changes on magnetic resonance imaging (MRI). Well-encapsulated, rim-enhancing lesion with mass effect was visualized at ventral side of lumbar spinal canal on 17 days after initial negative MRI, which was thought to be epidural abscess. It was revealed to be intradural in location on operation and successfully treated by drainage and antibiotics. Follow-up MRI showed resolution of abscess. Clinical significance and pathogenesis of this case was briefly discussed. PMID:27169060

  8. Rapidly Progressive Gas-containing Lumbar Spinal Epidural Abscess.

    PubMed

    Bang, Jin Hyuk; Cho, Keun-Tae

    2015-09-01

    Gas-containing (emphysematous) infections of the abdomen, pelvis, and extremities are well-known disease entities, which can potentially be life-threatening. They require aggressive medical and often surgical treatment. In the neurosurgical field, some cases of gas-containing brain abscess and subdural empyema have been reported. Sometimes they progress rapidly and even can cause fatal outcome. However, gas-containing spinal epidural abscess has been rarely reported and clinical course is unknown. We report on a case of rapidly progressive gas-containing lumbar spinal epidural abscess due to Enterococcus faecalis in a 72-year-old male patient with diabetes mellitus.

  9. Management of severe pain due to lumbar disk protrusion.

    PubMed

    Conroy, Liam

    2015-03-01

    Lumbar intervertebral disk protrusion can cause excruciating pain in severe cases, which can be exacerbated by activity such as sitting down and straining at stool. Acute sciatica due to disk rupture will improve within 1 to 3 months. The efficacy of drugs used for the management of sciatica in primary care is unclear. Severe cases can require opioid analgesia, however people taking opioids for pain relief frequently present with opioid-induced bowel dysfunction. The use of transforaminal steroid injections is a controversial issue and repeat steroid injections should be considered in light of the risk-benefit profile of the individual patient.

  10. Safety and Efficacy of Mini Open Transforaminal Lumbar Interbody Fusion

    PubMed Central

    Eissa, Ehab M.; Elmorsy, Haitham M.

    2016-01-01

    Objective Mini-transforaminal lumbar interbody fusion (Mini-TLIF) and other minimally invasive approaches introduced for the purpose of treating lumbar degenerative disc disease and instability are achieving high success and safety rates as the conventional approaches. Moreover, it has less soft tissue damage, minimal blood loss, and less hospital stay. Methods A prospective study was conducted from 2012 to 2014 on 28 patients who were subjected to Mini-open TLIF combined with transpedicular screw fixation for spondylolisthesis and degenerative disc disease. Two paramedian approaches were done, 4 cm for each, to insert the pedicular screws, along with inserting unilateral TLIF cage with autologous bone graft. Decompression was done either unilateral or bilateral according to the patient side of radiculopathy. Sixteen patients (57.2%) were diagnosed with degenerative spondylolisthesis, 7 patients (25%) were diagnosed with isthmic type spondylolisthesis, and 5 patients (17.8%) were diagnosed with degenerative disc disease, 2 of them(7.1%) had previous operations at the same level. Twenty patients (71.4%) were operated at the L4/5 level, and 8 patients (28.6%) at the L5/S1 level. Results All patients were able to ambulate the next day of surgery. The mean estimated blood loss was 251.79mL. The average hospital stay was 4.14 days. The average follow-up was 9 months. The mean visual analog scale was 1.86 at discharge, 1.68 after 3 months, and 1.38 after 6 months. After 6 months of the operation, MacNab's criteria were good in 23 patients and excellent in 5 patients. We had one case with transient weakness, 2 cases of screw malposition without clinical manifestations, and one case of infection. Conclusion Mini-TLIF approach is an efficient and safe approach for treating instability and degenerative diseases of the lumbar spine. The clinical outcome is encouraging and it may be an operation of choice for lumbar spinal fusion in selected patients. PMID:28127376

  11. Oblique lumbar spine radiographs: importance in young patients

    SciTech Connect

    Libson, E.; Bloom, R.A.; Dinari, G.; Robin, G.C.

    1984-04-01

    Spondylolysis is a direct precursor of spondylolisthesis and can lead to crippling back pain. Of 1,743 patients surveyed, including 936 who were asymptomatic and 807 with back pain, 165 (including 91 who were asymptomatic and 74 with back pain) had spondylolysis, which was seen only on oblique lumbar views in 20% of cases. Because of the high false-negative rate of AP and lateral views, oblique views are essential in children and young adults. As spondylolysis is rare above L3, radiographs can be limited to L3-S1. Significantly less spondylolysis was seen in persons older than 30 with back pain usually caused by disk degeneration.

  12. Prolapsed lumbar disk: value of CT in diagnosis.

    PubMed

    Rovira, M; Romero, F; Ibarra, B; Torrent, O

    1983-01-01

    A group of 40 patients with symptoms of prolapsed lumbar disk, seven of which were recurrent after surgery, was studied by computed tomography. In all cases, the diagnosis was confirmed by myelography and posterior surgery. Computed tomography was performed after the disappearance of myelographic contrast medium. Positive herniated disk was shown by computed tomography in 88%. In postoperative cases, computed tomography after intravenous contrast enhancement favored the recognition of postoperative scar, rather than recurrent herniation. Computed tomography also facilitated the diagnosis of spondylotic lesions, which may accompany herniated disks. Computed tomography should reduce the need for myelography, which is reserved for cases with doubtful computed tomographic findings.

  13. Contact stresses calculated for miniature slip rings

    NASA Technical Reports Server (NTRS)

    Albright, F. G.; Domerest, K. E.; Horton, J. C.

    1965-01-01

    Using mathematical formulations to plot the graphs of the contact preload versus the Hertzian load, calculations of unit loading of the preloaded brushes on slip rings can be made. This optimizes the design of contact brushes and miniature slip rings.

  14. Planetary science: Shepherds of Saturn's ring

    NASA Astrophysics Data System (ADS)

    Crida, Aurélien

    2015-09-01

    Saturn's F ring is chaperoned on both sides by the tiny moons Prometheus and Pandora. Numerical simulations show that this celestial ballet can result from the collision of two aggregates that evolved out of Saturn's main rings.

  15. How to Remove a Stuck Ring Safely

    MedlinePlus

    ... Hand Safety Fireworks Safety Lawnmower Safety Snowblower safety Pumpkin Carving Gardening Safety Turkey Carving Removing a Ring ... Hand Safety Fireworks Safety Lawnmower Safety Snowblower safety Pumpkin Carving Gardening Safety Turkey Carving Removing a Ring ...

  16. Shepherding model for Neptune's arc ring

    NASA Technical Reports Server (NTRS)

    Lissauer, J. J.

    1985-01-01

    A model to explain the confinement of the recently discovered incomplete arc ring around Neptune is developed. The ring may be azimuthally confined near a triangular (Trojan) point of an undiscovered satellite of Neptune. Radial diffusion of the ring particles can be prevented by shepherding torques of another moon. Two satellites with diameters of 100-200 km would be sufficient to confine the ring; such moons would be too small to have been photographed from earth.

  17. Random Implantation of Asymmetric Intracorneal Rings

    PubMed Central

    Peris-Martínez, Cristina; Gregori Gisbert, Irene

    2014-01-01

    Intracorneal ring employment for treating ectasia is widespread. Although the mechanism of action of intracorneal rings in the regularization of the corneal surface after its implantation is well known in most cases, there are still many doubts. We present a case of implanted intracorneal rings, where, despite the peculiar position of the rings, the patient gains lines of visual acuity and keratoconus remains stable. PMID:24711941

  18. Analysis of Alternative Ring Resonator Designs

    DTIC Science & Technology

    2014-08-01

    the ring strip of the antenna as in the case of the original design. Both the alternative dielectric laminate and the increased thickness laminate...adjustments to the geometry parameters. 2. Ring Resonator Antenna Design The ring resonator is a two port antenna consisting of a ring strip and two...differing thicknesses for resonator antennas of the same design suggests that the RF fields penetrate slightly more or that the resonator can “see” a

  19. Kinematics and dynamics of the Uranian rings

    NASA Technical Reports Server (NTRS)

    French, Richard G.

    1987-01-01

    The self-gravity model of apse alignment was tested by comparing its predictions about structure within the epsilon ring with an extensive set of observed occultation profiles covering a wide range of ring longitudes. The self-gravity model as presently constructed is inconsistent with the observations. The Lindblad resonance survey and Shepherd satellite ring perturbation are discussed. The kinematic model of the Uranian ring orbit was enhanced to accommodate Voyager observations as well as ground-based occultation observations.

  20. Optical fiber having wave-guiding rings

    DOEpatents

    Messerly, Michael J.; Dawson, Jay W.; Beach, Raymond J.; Barty, Christopher P. J.

    2011-03-15

    A waveguide includes a cladding region that has a refractive index that is substantially uniform and surrounds a wave-guiding region that has an average index that is close to the index of the cladding. The wave-guiding region also contains a thin ring or series of rings that have an index or indices that differ significantly from the index of the cladding. The ring or rings enable the structure to guide light.

  1. Environmental study of miniature slip rings

    NASA Technical Reports Server (NTRS)

    Radnik, J. L.

    1967-01-01

    Investigation studied the long term operation of miniature slip ring assembles in high vacuum of space and included the influence of ring, brush, and insulator materials on electrical noise and mechanical wear. Results show that soft metal vapor plating and niobium diselenide miniature slip rings are beneficial.

  2. O-ring gasket test fixture

    NASA Technical Reports Server (NTRS)

    Turner, James Eric (Inventor); Mccluney, Donald Scott (Inventor)

    1991-01-01

    An apparatus is presented for testing O-ring gaskets under a variety of temperature, pressure, and dynamic loading conditions. Specifically, this apparatus has the ability to simulate a dynamic loading condition where the sealing surface in contact with the O-ring moves both away from and axially along the face of the O-ring.

  3. A Ring Construction Using Finite Directed Graphs

    ERIC Educational Resources Information Center

    Bardzell, Michael

    2012-01-01

    In this paper we discuss an interesting class of noncommutative rings which can be constructed using finite directed graphs. This construction also creates a vector space. These structures provide undergraduate students connections between ring theory and graph theory and, among other things, allow them to see a ring unity element that looks quite…

  4. Rings of uranus: invisible and impossible?

    PubMed

    VAN Flandern, T C

    1979-06-08

    Neither the dynamical nor the optical properties of the rings of Uranus are easily understood, unless it is assumed that they are not rings in the ordinary sense but simply volatile material in the orbits of several individual small satellites. It is possible that other natural satellites may also leave such rings in their wakes.

  5. The Phase Shift in the Jumping Ring

    ERIC Educational Resources Information Center

    Jeffery, Rondo N.; Amiri, Farhang

    2008-01-01

    The popular physics demonstration experiment known as Thomson's Jumping Ring (JR) has been variously explained as a simple example of Lenz's law, or as the result of a phase shift of the ring current relative to the induced emf. The failure of the first-quadrant Lenz's law explanation is shown by the time the ring takes to jump and by levitation.…

  6. 21 CFR 870.3800 - Annuloplasty ring.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Annuloplasty ring. 870.3800 Section 870.3800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL...) Identification. An annuloplasty ring is a rigid or flexible ring implanted around the mitral or tricuspid...

  7. 21 CFR 870.3800 - Annuloplasty ring.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Annuloplasty ring. 870.3800 Section 870.3800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL...) Identification. An annuloplasty ring is a rigid or flexible ring implanted around the mitral or tricuspid...

  8. 21 CFR 870.3800 - Annuloplasty ring.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Annuloplasty ring. 870.3800 Section 870.3800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL...) Identification. An annuloplasty ring is a rigid or flexible ring implanted around the mitral or tricuspid...

  9. 21 CFR 870.3800 - Annuloplasty ring.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Annuloplasty ring. 870.3800 Section 870.3800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL...) Identification. An annuloplasty ring is a rigid or flexible ring implanted around the mitral or tricuspid...

  10. APS storage ring vacuum system

    SciTech Connect

    Niemann, R.C.; Benaroya, R.; Choi, M.; Dortwegt, R.J.; Goeppner, G.A.; Gonczy, J.; Krieger, C.; Howell, J.; Nielsen, R.W.; Roop, B.; Wehrle, R.B.

    1990-01-01

    The Advanced Photon Source synchrotron radiation facility, under construction at the Argonne National Laboratory, incorporates a large ring for the storage of 7 GeV positrons for the generation of photon beams for the facility's experimental program. The Storage Ring's 1104 m circumference is divided into 40 functional sectors. The sectors include vacuum, beam transport, control, acceleration and insertion device components. The vacuum system, which is designed to operate at a pressure of 1 n Torr, consists of 240 connected sections, the majority of which are fabricated from an aluminum alloy extrusion. The sections are equipped with distributed NeG pumping, photon absorbers with lumped pumping, beam position monitors, vacuum diagnostics and valving. The details of the vacuum system design, selected results of the development program and general construction plans are presented. 11 refs., 6 figs., 3 tabs.

  11. Behavioral Mapless Navigation Using Rings

    NASA Technical Reports Server (NTRS)

    Monroe, Randall P.; Miller, Samuel A.; Bradley, Arthur T.

    2012-01-01

    This paper presents work on the development and implementation of a novel approach to robotic navigation. In this system, map-building and localization for obstacle avoidance are discarded in favor of moment-by-moment behavioral processing of the sonar sensor data. To accomplish this, we developed a network of behaviors that communicate through the passing of rings, data structures that are similar in form to the sonar data itself and express the decisions of each behavior. Through the use of these rings, behaviors can moderate each other, conflicting impulses can be mediated, and designers can easily connect modules to create complex emergent navigational techniques. We discuss the development of a number of these modules and their successful use as a navigation system in the Trinity omnidirectional robot.

  12. Arrays of ultrasmall metal rings

    NASA Astrophysics Data System (ADS)

    Singh, Deepak K.; Krotkov, Robert V.; Xiang, Hongqi; Xu, Ting; Russell, Thomas P.; Tuominen, Mark T.

    2008-06-01

    In this paper, we present a simple method to fabricate ultra-high-density hexagonal arrays of ferromagnetic nanorings having 13 nm outer diameter, 5 nm inner diameter and 5 nm thickness. Cobalt magnetic nanorings were fabricated using a self-assembled diblock copolymer template with an angular evaporation of metal followed by an ion-beam etching. Magnetic measurements and theoretical calculations suggest that, at low fields, only the single domain and vortex states are important for rings of this size. The measured magnetization as a function of applied field shows a hysteresis that is consistent. These ultrasmall ferromagnetic rings have potential use in magnetic memory devices due to the simplicity of the preparation coupled with the ultra-high-density and geometry-controlled switching. This fabrication technique can be extended to other materials for applications in optics, sensing and nanoscale research.

  13. Drag of buoyant vortex rings

    NASA Astrophysics Data System (ADS)

    Vasel-Be-Hagh, Ahmadreza; Carriveau, Rupp; Ting, David S.-K.; Turner, John Stewart

    2015-10-01

    Extending from the model proposed by Vasel-Be-Hagh et al. [J. Fluid Mech. 769, 522 (2015), 10.1017/jfm.2015.126], a perturbation analysis is performed to modify Turner's radius by taking into account the viscous effect. The modified radius includes two terms; the zeroth-order solution representing the effect of buoyancy, and the first-order perturbation correction describing the influence of viscosity. The zeroth-order solution is explicit Turner's radius; the first-order perturbation modification, however, includes the drag coefficient, which is unknown and of interest. Fitting the photographically measured radius into the modified equation yields the time history of the drag coefficient of the corresponding buoyant vortex ring. To give further clarification, the proposed model is applied to calculate the drag coefficient of a buoyant vortex ring at a Bond number of approximately 85; a similar procedure can be applied at other Bond numbers.

  14. Fiber Ring Optical Gyroscope (FROG)

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The design, construction, and testing of a one meter diameter fiber ring optical gyro, using 1.57 kilometers of single mode fiber, are described. The various noise components: electronic, thermal, mechanical, and optical, were evaluated. Both dc and ac methods were used. An attempt was made to measure the Earth rotation rate; however, the results were questionable because of the optical and electronic noise present. It was concluded that fiber ring optical gyroscopes using all discrete components have many serious problems that can only be overcome by discarding the discrete approach and adapting an all integrated optic technique that has the laser source, modulator, detector, beamsplitters, and bias element on a single chip.

  15. Fourth-generation storage rings

    SciTech Connect

    Galayda, J. N.

    1999-11-16

    It seems clear that a linac-driven free-electron laser is the accepted prototype of a fourth-generation facility. This raises two questions: can a storage ring-based light source join the fourth generation? Has the storage ring evolved to its highest level of performance as a synchrotrons light source? The answer to the second question is clearly no. The author thinks the answer to the first question is unimportant. While the concept of generations has been useful in motivating thought and effort towards new light source concepts, the variety of light sources and their performance characteristics can no longer be usefully summed up by assignment of a ''generation'' number.

  16. Ball-joint grounding ring

    NASA Technical Reports Server (NTRS)

    Aperlo, P. J. A.; Buck, P. A.; Weldon, V. A.

    1981-01-01

    In ball and socket joint where electrical insulator such as polytetrafluoroethylene is used as line to minimize friction, good electrical contact across joint may be needed for lightning protection or to prevent static-charge build-up. Electrical contact is maintained by ring of spring-loaded fingers mounted in socket. It may be useful in industry for cranes, trailers, and other applications requiring ball and socket joint.

  17. The Friction of Piston Rings

    NASA Technical Reports Server (NTRS)

    Tischbein, Hans W

    1945-01-01

    The coefficient of friction between piston ring and cylinder liner was measured in relation to gliding acceleration, pressure, temperature, quantity of oil and quality of oil. Comparing former lubrication-technical tests, conclusions were drawn as to the state of friction. The coefficients of friction as figured out according to the hydrodynamic theory were compared with those measured by tests. Special tests were made on "oiliness." The highest permissible pressure was measured and the ratio of pressure discussed.

  18. Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 3: assessment of economic outcome.

    PubMed

    Ghogawala, Zoher; Whitmore, Robert G; Watters, William C; Sharan, Alok; Mummaneni, Praveen V; Dailey, Andrew T; Choudhri, Tanvir F; Eck, Jason C; Groff, Michael W; Wang, Jeffrey C; Resnick, Daniel K; Dhall, Sanjay S; Kaiser, Michael G

    2014-07-01

    A comprehensive economic analysis generally involves the calculation of indirect and direct health costs from a societal perspective as opposed to simply reporting costs from a hospital or payer perspective. Hospital charges for a surgical procedure must be converted to cost data when performing a cost-effectiveness analysis. Once cost data has been calculated, quality-adjusted life year data from a surgical treatment are calculated by using a preference-based health-related quality-of-life instrument such as the EQ-5D. A recent cost-utility analysis from a single study has demonstrated the long-term (over an 8-year time period) benefits of circumferential fusions over stand-alone posterolateral fusions. In addition, economic analysis from a single study has found that lumbar fusion for selected patients with low-back pain can be recommended from an economic perspective. Recent economic analysis, from a single study, finds that femoral ring allograft might be more cost-effective compared with a specific titanium cage when performing an anterior lumbar interbody fusion plus posterolateral fusion.

  19. [Functional status of patients after lumbar disc herniation surgery].

    PubMed

    Imamović, Maida Zonić; Hodzić, Mirsad; Duraković, Suada Kapidzić; Basić, Nedima Kapidzić; Cickusić, Amela; Imamović, Goran

    2010-01-01

    The aim of this study was to determine whether early rehabilitation from the first postoperative day after lumbar disc herniation surgery improved functional status of patients compared to the rehabilitation that started 3 weeks after surgery. Oswestry index was used for functional status assessment before surgery and after rehabilitation in 60 patients divided in 2 groups, i.e., early and control group of rehabilitation strated 3 weeks after surgery, 30 in each. Oswestry index values before surgery and after rehabilitation in the early rehabilitation group were 78.4 +/- 17 and 19.6 +/- 9.9, respectively (p < 0.0001) and in the control group the values were 79 +/- 13 and 37 +/- 14, respectively (p < 0.0001). The difference of Oswestry index before operation and after rehabilitation in the early rehabilitation group was 58.7 +/- 18.9, and in the control group 41.6 +/- 13.2 (p = 0.0001). Onset of rehabilitation from the first post operative day lead to better functional recovery compared to delayed rehabilitation 3 weeks after lumbar disc herniation surgery.

  20. Cortical blindness following posterior lumbar decompression and fusion.

    PubMed

    Agarwal, Nitin; Hansberry, David R; Goldstein, Ira M

    2014-01-01

    Perioperative vision loss following non-ocular surgery is a well-documented phenomenon. In particular, perioperative vision loss has been frequently cited following spinal surgery. Although the rate of vision compromise in spinal surgery is relatively low, the consequences can be quite severe and devastating for the patient. We report a 60-year-old woman who initially presented with back and left leg pain as well as paraparesis. Imaging studies of the lumbar spine showed bony erosion consistent with tumor infiltration of the L3 and L4 spinal segments. Laminectomy at the L2-L4 levels for decompression of the intraspinal tumor was performed. Pathology of the resected bone was consistent with metastatic adenocarincoma. Postoperatively, the patient suffered severe anemia and bilateral infarctions of the posterior cerebral arteries and occipital lobes resulting in vision compromise. Although a definitive pathogenesis remains unknown, preoperative cardiovascular issues and intraoperative hemodynamic instabilities have typically been implicated as high risk factors. High risk factors for this novel clinical presentation of visual compromise following posterior lumbar laminectomy with decompression for an intraspinal tumor are reported.

  1. Postural strategy changes with fatigue of the lumbar extensor muscles.

    PubMed

    Wilson, Erin L; Madigan, Michael L; Davidson, Bradley S; Nussbaum, Maury A

    2006-04-01

    The purpose of this study was to investigate the effect of lumbar extensor fatigue on postural strategy in response to a balance perturbation. Anteriorly-directed force perturbations were applied to the upper back with a padded pendulum and attempted to challenge the postural control system without eliciting a stepping response. In three separate sessions, subjects were perturbed both before and after a fatiguing protocol that induced lumbar extensor fatigue to one of three different fatigue levels. Postural strategy was quantified using center of pressure position along with joint angles and joint torques for the ankle, knee, hip, and "low back" joints. Results showed both proactive and reactive changes in postural strategy. Proactive changes involved a slight anterior lean prior to the perturbation, and reactive changes were consistent with a shift toward more of a hip strategy with fatigue. In addition, results suggested that subjects classified as moving mostly at the hip prior to fatigue were more affected by fatigue compared to subjects classified as moving roughly equal amounts at the ankle and hip prior to fatigue. Increasing fatigue level exaggerated some, but not all, of the changes in postural strategy with fatigue. These findings illustrate that neuromuscular fatigue can influence postural strategy in response to a balance perturbation.

  2. Analysis of failures and poor results of lumbar spine surgery.

    PubMed

    Fager, C A; Freidberg, S R

    1980-01-01

    The failures and poor results of lumbar spine surgery are analyzed in a retrospectively study of 105 consecutive patients referred to the authors for evaluation during 1976. Those who had a history of industrial or vehicular accident outnumbered others by about two to one. Review of histories, physical findings, and myelograms in most of the patients failed to substantiate the diagnosis of ruptured disc or nerve root compression. Many of the failures occurred in thos patients in whom little if any evidence of nerve root compression was found. The indications for surgery were poor in this group. Other failures occurred in patients who had improper, incomplete, or inadequate operations, especially those with lumbar spondylosis, a retained fragment of disc, or surgery at the wrong level. In addition to failure, poor results were recorded in patients who had significant nerve root or cauda equina injury from surgery, associated "arachnoiditis" which is thought to result from surgical trauma in many instances, or multiple operations leading to a hopelessly disabled state.

  3. Automated quantification of lumbar vertebral kinematics from dynamic fluoroscopic sequences

    NASA Astrophysics Data System (ADS)

    Camp, Jon; Zhao, Kristin; Morel, Etienne; White, Dan; Magnuson, Dixon; Gay, Ralph; An, Kai-Nan; Robb, Richard

    2009-02-01

    We hypothesize that the vertebra-to-vertebra patterns of spinal flexion and extension motion of persons with lower back pain will differ from those of persons who are pain-free. Thus, it is our goal to measure the motion of individual lumbar vertebrae noninvasively from dynamic fluoroscopic sequences. Two-dimensional normalized mutual information-based image registration was used to track frame-to-frame motion. Software was developed that required the operator to identify each vertebra on the first frame of the sequence using a four-point "caliper" placed at the posterior and anterior edges of the inferior and superior end plates of the target vertebrae. The program then resolved the individual motions of each vertebra independently throughout the entire sequence. To validate the technique, 6 cadaveric lumbar spine specimens were potted in polymethylmethacrylate and instrumented with optoelectric sensors. The specimens were then placed in a custom dynamic spine simulator and moved through flexion-extension cycles while kinematic data and fluoroscopic sequences were simultaneously acquired. We found strong correlation between the absolute flexionextension range of motion of each vertebra as recorded by the optoelectric system and as determined from the fluoroscopic sequence via registration. We conclude that this method is a viable way of noninvasively assessing twodimensional vertebral motion.

  4. The effect of massage on localized lumbar muscle fatigue

    PubMed Central

    Tanaka, Tim Hideaki; Leisman, Gerry; Mori, Hidetoshi; Nishijo, Kazushi

    2002-01-01

    Background There is not enough evidence to support the efficacy of massage for muscle fatigue despite wide utilization of the modality in various clinical settings. This study investigated the influence of massage application on localized back muscle fatigue. Methods Twenty-nine healthy subjects participated in two experimental sessions (massage and rest conditions). On each test day, subjects were asked to lie in the prone position on a treatment table and perform sustained back extension for 90 seconds. Subjects then either received massage on the lumbar region or rested for a 5 minute duration, then repeated the back extension movement. The median frequency (MDF), mean power frequency (MNF), and root mean square (RMS) amplitude of electromyographic signals during the 90 second sustained lumbar muscle contraction were analyzed. The subjective feeling of fatigue was then evaluated using the Visual Analogue Scale (VAS). Results MDF and MNF significantly declined with time under all conditions. There was no significant difference in MDF, MNF or RMS value change between before and after massage, or between rest and massage conditions. There was a significant increase in fatigue VAS at the end of the 2nd back extension with rest condition. There was a significant difference in fatigue VAS change between massage and rest condition. Conclusions A significant difference was observed between massage and rest condition on VAS for muscle fatigue. On EMG analysis, there were no significant differences to conclude that massage stimulation influenced the myoelectrical muscle fatigue, which is associated with metabolic and electrical changes. PMID:12377105

  5. Results of lumbar hemivertebral excision for congenital scoliosis.

    PubMed

    King, J D; Lowery, G L

    1991-07-01

    The purposes of this study were to determine the long-term correction achieved by excision of lumbar hemivertebrae and the risk attendant. Seven patients had a follow-up of 41.14 months for lumbar hemivertebral excisions. Six had two-stage anterior vertebral body excision and, 7-8 days later, posterior lamina and pedicle excision with fusion. One patient had a single-stage correction. After surgery, the patients were in pantaloon casts or braces for a minimum of 6 months (supine, first 6-12 weeks). Hemivertebrae were at L2 (N = 1), L3 (N = 1), L4-L5 (N = 1), and L5-S1 (N = 4). Preoperative curves or hemivertebral angles averaged 36.6 degrees (range, 30-52 degrees). Average age was 7.5 years (range, 22 months to 12.5 years). Mean follow-up was 41.14 months. Surgical correction of the seven cases averaged 28.0 degrees. Two-stage procedures yielded 29.7 degrees correction with no complications; single-stage yielded 18 degrees correction, and the only complication was an L5 nerve root paresis.

  6. [Biomechanical study of lumbar spine under different vibration conditions].

    PubMed

    Xiang, Pin; Du, Chengfei; Mo, Zhongjun; Gong, He; Wang, Lizhen; Fan, Yubo

    2015-02-01

    We observed the effect of vibration parameters on lumbar spine under different vibration conditions using finite element analysis method in our laboratory. In this study, the CT-images of L1-L5 segments were obtained. All images were used to develop 3D geometrical model using the Mimics10. 01 (Materialise, Belgium). Then it was modified using Geomagic Studio12. 0 (Raindrop Geomagic Inc. USA). Finite element (FE) mesh model was generated by Hypermesh11. 0 (Altair Engineering, Inc. USA) and Abaqus. Abaqus was used to calculate the stress distribution of L1-L5 under different vibration conditions. It was found that in a vibration cycle, tensile stress was occurred on lumbar vertebra mainly. Stress distributed evenly and stress concentration occurred on the left rear side of the upper endplate. The stress had no obvious changes under different frequencies, but the stress was higher when amplitude was greater. In conclusion, frequency and amplitude parameters have little effect on the stress distribution in vertebra. The stress magnitude is positively correlated with the amplitude.

  7. Lumbar spinal loads and muscle activity during a golf swing.

    PubMed

    Lim, Young-Tae; Chow, John W; Chae, Woen-Sik

    2012-06-01

    This study estimated the lumbar spinal loads at the L4-L5 level and evaluated electromyographic (EMG) activity of right and left rectus abdominis, external and internal obliques, erector spinae, and latissimus dorsi muscles during a golf swing. Four super VHS camcorders and two force plates were used to obtain three-dimensional (3D) kinematics and kinetics of golf swings performed by five male collegiate golfers. Average EMG levels for different phases of golf swing were determined. An EMG-assisted optimization model was applied to compute the contact forces acting on the L4-L5. The results revealed a mean peak compressive load of over six times the body weight (BW) during the downswing and mean peak anterior and medial shear loads approaching 1.6 and 0.6 BW during the follow-through phases. The peak compressive load estimated in this study was high, but less than the corresponding value (over 8 BW) reported by a previous study. Average EMG levels of different muscles were the highest in the acceleration and follow-through phases, suggesting a likely link between co-contractions of paraspinal muscles and lumbar spinal loads.

  8. Automated assessment of exclusion criteria for DXA lumbar spine scans.

    PubMed

    Barden, Howard S; Markwardt, Paul; Payne, Randy; Hawkins, Brent; Frank, Matt; Faulkner, Kenneth G

    2003-01-01

    Modern bone densitometry systems using dual-energy X-ray absorptiometry (DXA) automatically analyze lumbar spine scans and provide clinically important information concerning spine bone mineral density (BMD) and fracture risk. Lumbar spine BMD accurately reflects skeletal health and fracture risk in most cases, but degenerative diseases associated with aging may lead to the formation of reactive bone (osteophytes) and other confounding conditions that elevate BMD without a concomitant increase in bone strength or decrease in fracture risk. Automated densitometry software known as computer-aided densitometry (CAD) (GE Medical Systems Lunar) assists the user in identifying scans with common acquisition and analysis irregularities known to influence BMD values. Visual examination of 231 female spine scans measured with DXA found abnormal conditions that could influence BMD results in 29% of scans. The sensitivity and specificity of several criteria for identifying scans with conditions that could influence BMD were determined. A good criterion for identifying scans with abnormal conditions was a T-score difference of greater than 0.9 or 1.0 between L1-L4 mean and individual vertebrae. Criteria for excluding affected vertebrae were determined. Exclusion of affected vertebrae resulted in a mean BMD decrease of nearly 0.6 SD (T-score) among affected scans.

  9. Landscape of RNAs in human lumbar disc degeneration

    PubMed Central

    Pei, Yan-Jun; Wu, Zhi-Gang; Yu, Yang; Yang, Yong-Feng; Liu, Xu; Che, Lu; Ma, Chi-Jiao; Xie, Yan-Ke; Hu, Qing-Jie; Wan, Zhong-Yuan; Wang, Hai-Qiang

    2016-01-01

    Accumulating evidence indicates noncoding RNAs (ncRNAs) fine-tune gene expression with mysterious machinery. We conducted a combination of mRNA, miRNA, circRNA, LncRNA microarray analyses on 10 adults' lumbar discs. Moreover, we performed additional global exploration on RNA interacting machinery in terms of in silico computational pipeline. Here we show the landscape of RNAs in human lumbar discs. In general, the RNA-abundant landscape comprises 14,635 mRNAs (37.93%), 2,059 miRNAs (5.34%), 18,995 LncRNAs (49.23%) and 2,894 (7.5%) circRNAs. Chromosome 1 contributes for RNA transcription at most (10%). Bi-directional transcription contributes evenly for RNA biogenesis, in terms of 5′ to 3′ and 3′ to 5′. Despite the majority of circRNAs are exonic, antisense (1.49%), intergenic (0.035%), intragenic (1.69%), and intronic (6.29%) circRNAs should not be ignored. A single miRNA could interact with a multitude of circRNAs. Notably, CDR1as or ciRS-7 harbors 66 consecutive binding sites for miR-7-5p (previous miR-7), evidencing our pipeline. The majority of binding sites are perfect-matched (78.95%). Collectively, global landscape of RNAs sheds novel insights on RNA interacting mechanisms in human intervertebral disc degeneration. PMID:27542248

  10. Total Disc Replacement in Lumbar Degenerative Disc Diseases

    PubMed Central

    2015-01-01

    More than 10 years have passed since lumbar total disc replacement (LTDR) was introduced for the first time to the world market for the surgical management of lumbar degenerative disc disease (DDD). It seems like the right time to sum up the relevant results in order to understand where LTDR stands on now, and is heading forward to. The pathogenesis of DDD has been currently settled, but diagnosis and managements are still controversial. Fusion is recognized as golden standard of surgical managements but has various kinds of shortcomings. Lately, LTDR has been expected to replace fusion surgery. A great deal of LTDR reports has come out. Among them, more than 5-year follow-up prospective randomized controlled studies including USA IDE trials were expected to elucidate whether for LTDR to have therapeutic benefit compared to fusion. The results of these studies revealed that LTDR was not inferior to fusion. Most of clinical studies dealing with LTDR revealed that there was no strong evidence for preventive effect of LTDR against symptomatic degenerative changes of adjacent segment disease. LTDR does not have shortcomings associated with fusion. However, it has a potentiality of the new complications to occur, which surgeons have never experienced in fusion surgeries. Consequently, longer follow-up should be necessary as yet to confirm the maintenance of improved surgical outcome and to observe any very late complications. LTDR still may get a chance to establish itself as a substitute of fusion both nominally and virtually if it eases the concerns listed above. PMID:26713139

  11. Gibbs Ringing in Diffusion MRI

    PubMed Central

    Veraart, Jelle; Fieremans, Els; Jelescu, Ileana O.; Knoll, Florian; Novikov, Dmitry S.

    2016-01-01

    Purpose To study and reduce the effect of Gibbs ringing artifact on computed diffusion parameters. Methods We reduce the ringing by extrapolating the k-space of each diffusion weighted image beyond the measured part by selecting an adequate regularization term. We evaluate several regularization terms and tune the regularization parameter to find the best compromise between anatomical accuracy of the reconstructed image and suppression of the Gibbs artifact. Results We demonstrate empirically and analytically that the Gibbs artifact, which is typically observed near sharp edges in magnetic resonance images, has a significant impact on the quantification of diffusion model parameters, even for infinitesimal diffusion weighting. We find the second order total generalized variation to be a good choice for the penalty term to regularize the extrapolation of the k-space, as it provides a parsimonious representation of images, a practically full suppression of Gibbs ringing, and the absence of staircasing artifacts typical for total variation methods. Conclusions Regularized extrapolation of the k-space data significantly reduces truncation artifacts without compromising spatial resolution in comparison to the default option of window filtering. In particular, accuracy of estimating diffusion tensor imaging and diffusion kurtosis imaging parameters improves so much that unconstrained fits become possible. PMID:26257388

  12. Reflex ring laser amplifier system

    DOEpatents

    Summers, M.A.

    1983-08-31

    The invention is a method and apparatus for providing a reflex ring laser system for amplifying an input laser pulse. The invention is particularly useful in laser fusion experiments where efficient production of high-energy and high power laser pulses is required. The invention comprises a large aperture laser amplifier in an unstable ring resonator which includes a combination spatial filter and beam expander having a magnification greater than unity. An input pulse is injected into the resonator, e.g., through an aperture in an input mirror. The injected pulse passes through the amplifier and spatial filter/expander components on each pass around the ring. The unstable resonator is designed to permit only a predetermined number of passes before the amplified pulse exits the resonator. On the first pass through the amplifier, the beam fills only a small central region of the gain medium. On each successive pass, the beam has been expanded to fill the next concentric non-overlapping region of the gain medium.

  13. Determinants of the intention for using a lumbar support among home care workers with recurrent low back pain.

    PubMed

    Roelofs, Pepijn D D M; van Poppel, Mireille N M; Bierma-Zeinstra, Sita M A; van Mechelen, Willem

    2010-09-01

    In most effectiveness studies on lumbar supports for patients with low back pain, insufficient data are reported about adherence. In a secondary preventive RCT, we found beneficial effects and a good adherence among home care workers with low back pain. To target the use of lumbar supports on those patients who can benefit optimally from usage, we need to know why people are adherent. We used the attitude, social support and self-efficacy model to identify determinants for prolonged adherence to wearing a lumbar support. The strongest predictor for intending sustained use of a lumbar support was a positive attitude towards lumbar supports, explaining 41% of the variance (B = 1.31; p < 0.001). Social support and self-efficacy played a minor role. The intention for prolonged use of a lumbar support for workers with recurrent back pain was mainly explained by a positive attitude. The discomfort of a lumbar support was outweighed by perceived benefit.

  14. Vaginal rings for delivery of HIV microbicides

    PubMed Central

    Malcolm, R Karl; Fetherston, Susan M; McCoy, Clare F; Boyd, Peter; Major, Ian

    2012-01-01

    Following the successful development of long-acting steroid-releasing vaginal ring devices for the treatment of menopausal symptoms and contraception, there is now considerable interest in applying similar devices to the controlled release of microbicides against HIV. In this review article, the vaginal ring concept is first considered within the wider context of the early advances in controlled-release technology, before describing the various types of ring device available today. The remainder of the article highlights the key developments in HIV microbicide-releasing vaginal rings, with a particular focus on the dapivirine ring that is presently in late-stage clinical testing. PMID:23204872

  15. Oxygen ions observed near Saturn's A ring.

    PubMed

    Waite, J H; Cravens, T E; Ip, W-H; Kasprzak, W T; Luhmann, J G; McNutt, R L; Niemann, H B; Yelle, R V; Mueller-Wodarg, I; Ledvina, S A; Scherer, S

    2005-02-25

    Ions were detected in the vicinity of Saturn's A ring by the Ion and Neutral Mass Spectrometer (INMS) instrument onboard the Cassini Orbiter during the spacecraft's passage over the rings. The INMS saw signatures of molecular and atomic oxygen ions and of protons, thus demonstrating the existence of an ionosphere associated with the A ring. A likely explanation for these ions is photoionization by solar ultraviolet radiation of neutral O2 molecules associated with a tenuous ring atmosphere. INMS neutral measurements made during the ring encounter are dominated by a background signal.

  16. Signal and power roll ring testing update

    NASA Technical Reports Server (NTRS)

    Smith, Dennis W.

    1989-01-01

    The development of the roll ring as a long-life, low-torque alternative to the slip ring is discussed. A roll ring consists of one or more circular flexures captured by their own spring force in the annular space between two concentric conductors or contact rings. The advantages of roll rings over other types of electrical transfer devices are: extremely low drag torque, high transfer efficiencies in high-power configurations, extremely low wear debris generation, long life, and low weight for high-power applications.

  17. Wavelength-tunable optical ring resonators

    DOEpatents

    Watts, Michael R.; Trotter, Douglas C.; Young, Ralph W.; Nielson, Gregory N.

    2009-11-10

    Optical ring resonator devices are disclosed that can be used for optical filtering, modulation or switching, or for use as photodetectors or sensors. These devices can be formed as microdisk ring resonators, or as open-ring resonators with an optical waveguide having a width that varies adiabatically. Electrical and mechanical connections to the open-ring resonators are made near a maximum width of the optical waveguide to minimize losses and thereby provide a high resonator Q. The ring resonators can be tuned using an integral electrical heater, or an integral semiconductor junction.

  18. Wavelength-tunable optical ring resonators

    DOEpatents

    Watts, Michael R.; Trotter, Douglas C.; Young, Ralph W.; Nielson, Gregory N.

    2011-07-19

    Optical ring resonator devices are disclosed that can be used for optical filtering, modulation or switching, or for use as photodetectors or sensors. These devices can be formed as microdisk ring resonators, or as open-ring resonators with an optical waveguide having a width that varies adiabatically. Electrical and mechanical connections to the open-ring resonators are made near a maximum width of the optical waveguide to minimize losses and thereby provide a high resonator Q. The ring resonators can be tuned using an integral electrical heater, or an integral semiconductor junction.

  19. Noncircular features in Saturn's rings II: The C ring

    NASA Astrophysics Data System (ADS)

    Nicholson, Philip D.; French, Richard G.; McGhee-French, Colleen A.; Hedman, Matthew M.; Marouf, Essam A.; Colwell, Joshua E.; Lonergan, Katherine; Sepersky, Talia

    2014-10-01

    We present a comprehensive survey of sharp-edged features in Saturn's C ring, using data from radio and stellar occultation experiments carried out by the Cassini spacecraft over a period of more than five years. Over 100 occultations are included in the combined data set, enabling us to identify systematic radial perturbations as small as 200 m on the edges of ringlets and gaps. We systematically examine all of the noncircular features in the C ring, refine the eccentricities, precession rates and width variations of the known eccentric ringlets, identify connections between several noncircular gap and ringlet edges and nearby satellite resonances, and report the discovery of a host of free normal modes on ring and gap edges. We confirm a close association between the Titan (or Colombo) ringlet (a = 77878.7 km) and the Titan 1:0 apsidal resonance: the apoapse of the ringlet is nearly aligned with Titan's mean longitude, and the pattern speed closely matches Titan's mean motion. Similar forced perturbations associated with the Titan resonance are detectable in more than two dozen other features located throughout the inner C ring as far as 3500 km from the Titan resonance. The inner edge of the Titan ringlet exhibits several strong outer Lindblad resonance (OLR-type) normal modes, and scans of the outer edge reveal inner Lindblad resonance (ILR-type) normal modes. The Maxwell ringlet (a = 87,510 km), in contrast, appears to be a freely-precessing eccentric ringlet, with post-fit RMS residuals for the inner and outer edges of only 0.23 and 0.16 km, respectively. The best-fitting edge precession rates differ by over 10 times the estimated uncertainty in the rate of the inner edge, consistent with a slow libration about an equilibrium configuration on a decadal timescale. Using self-gravity models for ringlet apse alignment, we estimate the masses and surface densities of the Titan and Maxwell ringlets. The Bond ringlet (a = 88,710 km), about 17 km wide, shows no free

  20. Lumbar Extension during Stoop Lifting is Delayed by the Load and Hamstring Tightness

    PubMed Central

    Iwasaki, Risa; Yokoyama, Ginga; Kawabata, Satoshi; Suzuki, Tomotaka

    2014-01-01

    [Purpose] This study investigated the relationship between lumbar pelvic rhythm and the physical characteristics of stoop lifting. [Subjects and Methods] Participants performed a stoop lifting task under two conditions: with and without load. We assessed the lumbar kyphosis and sacral inclination angles using the SpinalMouse® system, as well as hamstring flexibility. During stoop lifting, surface electromyograms and the lumbar and sacral motions were recorded using a multi-channel telemetry system and flexible electrogoniometers. [Results] In the initial phase of lifting, lumbar extension was delayed by load; the delay showed a negative correlation with sacral inclination angle at trunk flexion, whereas a positive correlation was observed with electromyogram activity of the lumbar multifidus. Additionally, a positive correlation was observed between sacral inclination angle and hip flexion range of motion during the straight leg raise test. [Conclusion] We found that a disorder of the lumbar pelvic rhythm can be caused by both load and hamstring tightness. In the initial phase of stoop lifting, delayed lumbar extension is likely to lead to an increase in spinal instability and stress on the posterior ligamentous system. This mechanism shows that stoop lifting of a load may be harmful to the lower back of people with hamstring tightness. PMID:24567676

  1. Factors associated with low levels of lumbar strength in adolescents in Southern Brazil☆

    PubMed Central

    Silva, Diego Augusto Santos; Gonçalves, Eliane Cristina de Andrade; Grigollo, Leoberto Ricardo; Petroski, Edio Luiz

    2014-01-01

    OBJECTIVE: To determine the prevalence and factors associated with low levels of lumbar strength in adolescents. METHOD: This was a cross-sectional study involving 601 adolescents, aged 14 to 17 years, enrolled in public schools in the western region of Santa Catarina State - Southern Brazil. Lumbar strength was analyzed by the lumbar extension test developed by the Canadian Society of Exercise Physiology, which proposes different cutoffs for boys and girls. Independent variables were sex, age, socioeconomic status, dietary habits, alcohol consumption, physical activity, and aerobic fitness. For data analysis, univariate and multivariate logistic regression were used, with significance level of 5%. RESULTS: The prevalence of low levels of lumbar strength was 27.3%. The population subgroups most likely to present low levels of lumbar strength were females (OR: 1.54, 95% CI : 1.06 to 2.23), adolescents with low levels of aerobic fitness (OR: 2.10, 95% CI: 1.41 to 3.11) and the overweight (OR: 2.28, 95% CI: 1.35 to 3.81). CONCLUSION: Almost one-third of the studied students have low levels of lumbar strength. Interventions in the school population should be taken with special attention to female adolescents, those with low levels of aerobic fitness, and those with overweight, as these population subgroups were most likely to demostrate low levels of lumbar strength. PMID:25511000

  2. More on five dimensional EVH black rings

    NASA Astrophysics Data System (ADS)

    Ghodsi, Ahmad; Golchin, Hanif; Sheikh-Jabbari, M. M.

    2014-09-01

    In this paper we continue our analysis of arXiv:1308.1478 and study in detail the parameter space of three families of doubly spinning black ring solutions: balanced black ring, unbalanced ring and dipole-charged balanced black rings. In all these three families the Extremal Vanishing Horizon (EVH) ring appears in the vanishing limit of the dimensionful parameter of the solution which measures the ring size. We study the near horizon limit of the EVH black rings and for all three cases we find a (pinching orbifold) AdS3 throat with the AdS3 radius ℓ 2 = 8 G 5 M/(3 π) where M is the ring mass and G 5 is the 5d Newton constant. We also discuss the near horizon limit of near-EVH black rings and show that the AdS3 factor is replaced with a generic BTZ black hole. We use these results to extend the EVH/CFT correspondence for black rings, a 2d CFT dual to near-EVH black rings.

  3. Nuclear Rings in Galaxies - A Kinematic Perspective

    NASA Technical Reports Server (NTRS)

    Mazzuca, Lisa M.; Swaters, Robert A.; Knapen, Johan H.; Veilleux, Sylvain

    2011-01-01

    We combine DensePak integral field unit and TAURUS Fabry-Perot observations of 13 nuclear rings to show an interconnection between the kinematic properties of the rings and their resonant origin. The nuclear rings have regular and symmetric kinematics, and lack strong non-circular motions. This symmetry, coupled with a direct relationship between the position angles and ellipticities of the rings and those of their host galaxies, indicate the rings are in the same plane as the disc and are circular. From the rotation curves derived, we have estimated the compactness (v(sup 2)/r) up to the turnover radius, which is where the nuclear rings reside. We find that there is evidence of a correlation between compactness and ring width and size. Radially wide rings are less compact, and thus have lower mass concentration. The compactness increases as the ring width decreases. We also find that the nuclear ring size is dependent on the bar strength, with weaker bars allowing rings of any size to form.

  4. Leapfrogging of multiple coaxial viscous vortex rings

    NASA Astrophysics Data System (ADS)

    Cheng, M.; Lou, J.; Lim, T. T.

    2015-03-01

    A recent theoretical study [Borisov, Kilin, and Mamaev, "The dynamics of vortex rings: Leapfrogging, choreographies and the stability problem," Regular Chaotic Dyn. 18, 33 (2013); Borisov et al., "The dynamics of vortex rings: Leapfrogging in an ideal and viscous fluid," Fluid Dyn. Res. 46, 031415 (2014)] shows that when three coaxial vortex rings travel in the same direction in an incompressible ideal fluid, each of the vortex rings alternately slips through (or leapfrogs) the other two ahead. Here, we use a lattice Boltzmann method to simulate viscous vortex rings with an identical initial circulation, radius, and separation distance with the aim of studying how viscous effect influences the outcomes of the leapfrogging process. For the case of two identical vortex rings, our computation shows that leapfrogging can be achieved only under certain favorable conditions, which depend on Reynolds number, vortex core size, and initial separation distance between the two rings. For the case of three coaxial vortex rings, the result differs from the inviscid model and shows that the second vortex ring always slips through the leading ring first, followed by the third ring slipping through the other two ahead. A simple physical model is proposed to explain the observed behavior.

  5. Leapfrogging of multiple coaxial viscous vortex rings

    SciTech Connect

    Cheng, M. Lou, J.; Lim, T. T.

    2015-03-15

    A recent theoretical study [Borisov, Kilin, and Mamaev, “The dynamics of vortex rings: Leapfrogging, choreographies and the stability problem,” Regular Chaotic Dyn. 18, 33 (2013); Borisov et al., “The dynamics of vortex rings: Leapfrogging in an ideal and viscous fluid,” Fluid Dyn. Res. 46, 031415 (2014)] shows that when three coaxial vortex rings travel in the same direction in an incompressible ideal fluid, each of the vortex rings alternately slips through (or leapfrogs) the other two ahead. Here, we use a lattice Boltzmann method to simulate viscous vortex rings with an identical initial circulation, radius, and separation distance with the aim of studying how viscous effect influences the outcomes of the leapfrogging process. For the case of two identical vortex rings, our computation shows that leapfrogging can be achieved only under certain favorable conditions, which depend on Reynolds number, vortex core size, and initial separation distance between the two rings. For the case of three coaxial vortex rings, the result differs from the inviscid model and shows that the second vortex ring always slips through the leading ring first, followed by the third ring slipping through the other two ahead. A simple physical model is proposed to explain the observed behavior.

  6. Small Satellites Embedded in Dense Planetary Rings

    NASA Astrophysics Data System (ADS)

    Hahn, J. M.

    2005-08-01

    A small satellite that inhabits a narrow gap in an dense planetary ring, such as Pan, will excite wakes at the gap edges, as well as spiral waves deeper in the ring. As the satellite disturbs the ring, it also draws angular momentum from the ring matter that orbits just interior to the satellite, while depositing that angular momentum among the ring particles that orbit just exterior. This outward transport of angular momentum causes the orbits of the nearby ring particles to slowly shrink, dragging along with them the satellite in its gap. This inward motion is of course type II migration that is familiar from planet formation theory. The significance of type II migration, if any, will also be assessed for the small satellites that orbit within Saturn's rings.

  7. Apse Alignment of the Uranian Rings

    NASA Astrophysics Data System (ADS)

    Mosqueira, Ignacio; Estrada, Paul R.

    2002-08-01

    An explanation of the dynamical mechanism for apse alignment of the eccentric uranian rings is necessary before observations can be used to determine properties such as ring masses, particle sizes, and elasticities. The leading model (P. Goldreich and S. Tremaine 1979, Astron J.84, 1638-1641) relies on the ring self-gravity to accomplish this task, yet it yields equilibrium masses which are not in accord with Voyager radio measurements. We explore possible solutions such that the self-gravity and the collisional terms are both involved in the process of apse alignment. We consider limits that correspond to a hot and a cold ring, and we show that pressure terms may play a significant role in the equilibrium conditions for the narrow uranian rings. In the cold ring case, where the scale height of the ring near periapse is comparable to the ring particle size, we introduce a new pressure correction pertaining to a region of the ring where the particles are locked in their relative positions and jammed against their neighbors and the velocity dispersion is so low that the collisions are nearly elastic. In this case, we find a solution such that the ring self-gravity maintains apse alignment against both differential precession ( m=1 mode) and the fluid pressure. We apply this model to the uranian α ring and show that, compared to the previous self-gravity model, the mass estimate for this ring increases by an order of magnitude. In the case of a hot ring, where the scale height can reach a value as much as 50 times the particle size, we find velocity dispersion profiles that result in pressure forces which act in such a way as to alter the ring equilibrium conditions, again leading to a ring mass increase of an order of magnitude. We find that such a velocity dispersion profile would require a different mechanism than is currently envisioned for establishing a heating/cooling balance in a finite-sized, inelastic particle ring. Finally, we introduce an important

  8. A search for cold water rings

    NASA Technical Reports Server (NTRS)

    Cheney, R. E.

    1981-01-01

    SAR imagery obtained by Seasat in the Sargasso Sea during 1978 is examined for cold ring signatures. One orbit on August 26 is thought to have imaged the edge of a cold ring, although the ring's position was not well known at the time. During another orbit on September 23, drifting buoy and expendable bathythermography data furnished conclusive evidence that the ring was centered directly in the SAR swath. Although some suggestive patterns are visible in the images, it is not clear that cold rings can be identified by SAR, even though dynamically similar features, such as the Gulf Stream and warm rings, can be accurately detected. The suggestion is made that cold rings may be imaged inadequately because of their lack of surface temperature gradient.

  9. On the Janus-Epimetheus Ring

    NASA Astrophysics Data System (ADS)

    Winter, Othon; Souza, Alexandre; Sfait, Rafael; Giuliatti Winter, Silvia; Mourão, Decio; Foryta, Dietmar

    2016-10-01

    Cassini spacecraft found a new and unique ring to share a trajectory with Janus and Epimetheus, co-orbital satellites of Saturn. Analyzing Cassini images, we found that the Janus-Epimetheus ring is a continuous and smooth ring, which can only be seen by Cassini's camera at very high phase angles, not being observed at other geometries, as a `firefly' behavior. We also found a very short mean lifetime for the ring particles, less than a couple of decades. Consequently, the ring needs to be constantly replenished. Using a collisional model of micrometeoroids on the satellites' surfaces we found that it produces a faint ring that is fully compatible with the Janus-Epimitheus ring. We also verified that the steady state of the generated particles distribution corresponds to that of the light scattering regime responsible for the `firefly' behavior.

  10. Should routine MRI of the lumbar spine be required prior to lumbar epidural steroid injection for sciatica pain?

    PubMed Central

    Ghaly, Ramis F.; Lissounov, Alexei; Candido, Kenneth D.; Knezevic, Nebojsa Nick

    2015-01-01

    Background: We describe three patients who received lumbar epidural steroid injections (LESI) for lumbosacral radicular pain that resulted in worsening of their symptoms. The procedures were performed following a review of remote diagnostic imaging studies. These cases demonstrate the lack of consensus in pain management domains for how to approach the workup and treatment of persistent/chronic low back pain, with a noted fragmentation in pain management strategies and applied therapies. Case Description: We present three patients; two female patients (37 and 38 years old) undergoing LESI for remotely diagnosed disc herniations, and one 61-year-old male receiving an LESI for a presumed, unverified lumbar intervertebral disc disorder. Following a worsening of symptoms after LESI, neurosurgical consultations ultimately determined the presence of, respectively, an epidural hematoma, a neurilemoma, and a lung cancer metastasis to the sacrum as the source of symptoms, instead of being due to the intervertebral disc pathology. Conclusions: We would like to emphasize several principles in the diagnosis and use of imaging of the lumbosacral region prior to undertaking invasive neuraxial procedures. PMID:25883840

  11. Effect of changing lumbar stiffness by single facet joint dysfunction on the responsiveness of lumbar muscle spindles to vertebral movement

    PubMed Central

    Reed, William R.; Pickar, Joel G.; Long, Cynthia R.

    2014-01-01

    Objective: Individuals experiencing low back pain often present clinically with intervertebral joint dysfunction. The purpose of this study was to determine whether relative changes in stiffness at a single spinal joint alters neural responsiveness of lumbar muscle spindles to either vertebral movement or position. Methods: Muscle spindle discharge was recorded in response to 1mm L6 ramp and hold movements (0.5mm/s) in the same animal for lumbar laminectomy-only (n=23), laminectomy & L5/6 facet screw (n=19), laminectomy & L5/6 facetectomy (n=5) conditions. Mean instantaneous frequency (MIF) was calculated for the ramp-up, hold, ramp-down and post-ramp phases during each joint condition. Results: Mean MIFs were not significantly different between the laminectomy-only and the other two types of joint dysfunction for the ramp-up, hold, ramp-down, or post-ramp phases. Conclusion: Stiffness changes caused by single facet joint dysfunction failed to alter spindle responses during slow 1mm ramp and hold movements of the L6 vertebra. PMID:24932020

  12. The Use of Percutaneous Lumbar Fixation Screws for Bilateral Pedicle Fractures with an Associated Dislocation of a Lumbar Disc Prosthesis

    PubMed Central

    Harrison, William D.; Harrison, David J.

    2013-01-01

    Study Design. Case report. Objective. To identify a safe technique for salvage surgery following complications of total disc replacement. Summary of Background Data. Lumbar total disc replacement (TDR) is considered by some as the gold standard for discogenic back pain. Revision techniques for TDR and their complications are in their infancy. This case describes a successful method of fixation for this complex presentation. Methods and Results. A 48-year-old male with lumbar degenerative disc disease and no comorbidities. Approximately two weeks postoperatively for a TDR, the patient represented with acute severe back pain and the TDR polyethylene inlay was identified as dislocated anteriorly. Subsequent revision surgery failed immediately as the polyethylene inlay redislocated intraoperatively. Further radiology identified bilateral pedicle fractures, previously unseen on the plain films. The salvage fusion of L5/S1 reutilized the anterior approach with an interbody fusion cage and bone graft. The patient was then turned intraoperatively and redraped. The percutaneous pedicle screws were used to fix L5 to the sacral body via the paracoccygeal corridor. Conclusion. The robust locking screw in the percutaneous screw allowed a complete fixation of the pedicle fractures. At 3-year followup, the patient has an excellent result and has returned to playing golf. PMID:24294533

  13. The Multiple Benefits of Minimally Invasive Spinal Surgery: Results Comparing Transforaminal Lumbar Interbody Fusion and Posterior Lumbar Fusion

    PubMed Central

    Starkweather, Angela R.; Witek-Janusek, Linda; Nockels, Russ P.; Peterson, Jonna; Mathews, Herb L.

    2013-01-01

    Minimally invasive transforaminal lumbar interbody fusion (TLIF) offers equivalent postoperative fusion rates compared to posterior lumbar fusion (PLF) and minimizes the amount of iatrogenic injury to the spinal muscles. The objective of this study was to examine the difference in pain perception, stress, mood disturbance, quality of life, and immunological indices throughout the perioperative course among patients undergoing TLIF and PLF. A prospective, nonrandomized descriptive design was used to evaluate these measures among patients undergoing TLIF (n = 17) or PLF (n = 18) at 1 week prior to surgery (T1), the day of surgery (T2), 24 hours postoperatively (T3), and 6 weeks postoperatively (T4). Among TLIF patients, pain, stress, fatigue, and mood disturbance were significantly decreased at the 6-week follow-up visit (T4) compared to patients who underwent PLF. The TLIF group also demonstrated significantly higher levels (near baseline) of CD8 cells atT4 than the PLF group. Interleukin-6 levels were significantly higher in the TLIF group as well, which may be an indicator of ongoing nerve regeneration and healing. Knowledge concerning the effect of pain and the psychological experience on immunity among individuals undergoing spinal fusion can help nurses tailor interventions to improve outcomes, regardless of the approach used. PMID:18330408

  14. Feasibility of a ring FEL at low emittance storage rings

    NASA Astrophysics Data System (ADS)

    Agapov, I.

    2015-09-01

    A scheme for generating coherent radiation at latest generation low emittance storage rings such as PETRA III at DESY (Balewski et al., 2004 [1]) is proposed. The scheme is based on focusing and subsequent defocusing of the electron beam in the longitudinal phase space at the undulator location. The expected performance characteristics are estimated for radiation in the wavelength range of 500-1500 eV. It is shown that the average brightness is increased by several orders of magnitude compared to spontaneous undulator radiation, which can open new perspectives for photon-hungry soft X-ray spectroscopy techniques.

  15. Cadmium toxicity to ringed seals (Phoca hispida): an epidemiological study of possible cadmium-induced nephropathy and osteodystrophy in ringed seals (Phoca hispida) from Qaanaaq in Northwest Greenland.

    PubMed

    Sonne-Hansen, C; Dietz, R; Leifsson, P S; Hyldstrup, L; Riget, F F

    2002-08-05

    The Greenland marine food chains contain high levels of cadmium, mercury and selenium. Concentrations of cadmium in the kidney of ringed seals (Phoca hispida) from the municipalities of Qaanaaq and Upernavik (Northwest Greenland) are among the highest recorded in the Arctic. The purpose of the study was to determine whether cadmium-induced damage in the kidneys and the skeletal system could be detected among 100 ringed seals from Northwest Greenland. The cadmium concentrations in the kidney cortex ranged from 0 to 248 microg/g wet weight (mean=44.5, N=100) in the 99 kidneys examined. Experience from cadmium-poisoned humans and laboratory mammals indicates that concentrations above 50-200 microg/g wet wt. may induce histopathological changes. Overall, 31 of the ringed seals had cadmium concentrations in the kidney cortex above 50 microg/g wet wt., 11 had concentrations above 100 and one had a concentration above 200 microg/g wet wt. Obvious histopathological changes (categorised mainly as glomerulonephritis) were found in 10 of the seals; however, none of these changes could be attributed to cadmium-induced renal damage (mainly tubulopathy) as described for other species. Damage to the proximal kidney tubules is known to induce demineralisation of the skeletal system (Fanconi's syndrome). Therefore, the three lowest lumbar vertebrae were scanned in 91 seals to measure the content of calcium. The 10 cases of nephropathy could neither be linked to the degree of mineralisation of the skeleton nor to the cadmium concentrations. Furthermore, the degree of mineralisation of the skeleton was not correlated with the cadmium concentration, age or sex. It can therefore be concluded that despite high levels of cadmium, none of the ringed seals showed any signs of cadmium-induced nephropathy or osteodystrophy. This might be explained by the composition of the ringed seals diet, which contains high levels of vitamin D, calcium, phosphorus, zinc, selenium and protein. These

  16. Effect of Direct Vertebral Rotation on the Uninstrumented Lumbar Curve in Thoracic Adolescent Idiopathic Scoliosis

    PubMed Central

    Kim, Sung-Soo; Suk, Se-Il

    2017-01-01

    Study Design Retrospective study. Purpose To determine the effect and direction of direct vertebral rotation (DVR) in the lowest instrumented vertebra (LIV) on the uninstrumented lumbar curve depending on the lumbar modifier used for the correction of thoracic adolescent idiopathic scoliosis. Overview of Literature DVR in the LIV should be implemented in a different direction to obtain better spontaneous lumbar correction depending on the preoperative lumbar spine modifier. Methods We retrospectively analyzed 160 patients with thoracic adolescent idiopathic scoliosis treated by pedicle screw instrumentation and rod derotation. Patients who had a distal fusion level between T11 and L1 were divided into two groups: the DVR group versus the No-DVR group. Each group was divided into subgroups depending on the lumbar modifier used: the DVR-A, B, and C groups versus the No-DVR-A, B, and C groups. The DVR-A group was subdivided into two subgroups depending on the direction of screw rotation in the LIV: the DVR-A-O group (opposite direction) and the DVR-A-S group (same direction). Results There were no significant differences in the preoperative curve characteristics between the two groups. The preoperative lumbar curve was corrected in 70% of the patients in the DVR group and in 56% in the No-DVR group. Spontaneous coronal correction of the lumbar curve was better in the DVR-A-S group than that in the No-DVR-A group. However, the DVR-A-O group had the higher incidence of adding-on deformity. The DVR-B and C groups showed better spontaneous correction of lumbar coronal magnitude, apical vertebral translation, and rotation and the LIV tilting. Conclusions In lumbar modifiers B and C, screws in the LIV have to be rotated opposite to the direction of the screw rotation of the main thoracic curve; however, in modifier A, the screws have to be rotated in the same direction. PMID:28243381

  17. Lumbar Disc Degenerative Disease: Disc Degeneration Symptoms and Magnetic Resonance Image Findings

    PubMed Central

    Saleem, Shafaq; Rehmani, Muhammad Asim Khan; Raees, Aisha; Alvi, Arsalan Ahmad; Ashraf, Junaid

    2013-01-01

    Study Design Cross sectional and observational. Purpose To evaluate the different aspects of lumbar disc degenerative disc disease and relate them with magnetic resonance image (MRI) findings and symptoms. Overview of Literature Lumbar disc degenerative disease has now been proven as the most common cause of low back pain throughout the world. It may present as disc herniation, lumbar spinal stenosis, facet joint arthropathy or any combination. Presenting symptoms of lumbar disc degeneration are lower back pain and sciatica which may be aggravated by standing, walking, bending, straining and coughing. Methods This study was conducted from January 2012 to June 2012. Study was conducted on the diagnosed patients of lumbar disc degeneration. Diagnostic criteria were based upon abnormal findings in MRI. Patients with prior back surgery, spine fractures, sacroiliac arthritis, metabolic bone disease, spinal infection, rheumatoid arthritis, active malignancy, and pregnancy were excluded. Results During the targeted months, 163 patients of lumbar disc degeneration with mean age of 43.92±11.76 years, came into Neurosurgery department. Disc degeneration was most commonly present at the level of L4/L5 105 (64.4%).Commonest types of disc degeneration were disc herniation 109 (66.9%) and lumbar spinal stenosis 37 (22.7%). Spondylolisthesis was commonly present at L5/S1 10 (6.1%) and associated mostly with lumbar spinal stenosis 7 (18.9%). Conclusions Results reported the frequent occurrence of lumbar disc degenerative disease in advance age. Research efforts should endeavor to reduce risk factors and improve the quality of life. PMID:24353850

  18. Contribution of Hamstring Fatigue to Quadriceps Inhibition Following Lumbar Extension Exercise

    PubMed Central

    Hart, Joseph M.; Kerrigan, D. Casey; Fritz, Julie M.; Saliba, Ethan N.; Gansneder, Bruce; Ingersoll, Christopher D.

    2006-01-01

    The purpose of this study was to determine the contribution of hamstrings and quadriceps fatigue to quadriceps inhibition following lumbar extension exercise. Regression models were calculated consisting of the outcome variable: quadriceps inhibition and predictor variables: change in EMG median frequency in the quadriceps and hamstrings during lumbar fatiguing exercise. Twenty-five subjects with a history of low back pain were matched by gender, height and mass to 25 healthy controls. Subjects performed two sets of fatiguing isometric lumbar extension exercise until mild (set 1) and moderate (set 2) fatigue of the lumbar paraspinals. Quadriceps and hamstring EMG median frequency were measured while subjects performed fatiguing exercise. A burst of electrical stimuli was superimposed while subjects performed an isometric maximal quadriceps contraction to estimate quadriceps inhibition after each exercise set. Results indicate the change in hamstring median frequency explained variance in quadriceps inhibition following the exercise sets in the history of low back pain group only. Change in quadriceps median frequency explained variance in quadriceps inhibition following the first exercise set in the control group only. In conclusion, persons with a history of low back pain whose quadriceps become inhibited following lumbar paraspinal exercise may be adapting to the fatigue by using their hamstring muscles more than controls. Key Points A neuromuscular relationship between the lumbar paraspinals and quadriceps while performing lumbar extension exercise may be influenced by hamstring muscle fatigue. QI following lumbar extension exercise in persons with a history of LBP group may involve significant contribution from the hamstring muscle group. More hamstring muscle contribution may be a necessary adaptation in the history of LBP group due to weaker and more fatigable lumbar extensors. PMID:24198683

  19. The F ring: Saturn's crooked halo?

    NASA Astrophysics Data System (ADS)

    Nicholson, P. D.; French, R. G.; Bosh, A. S.

    1999-09-01

    HST observations of the ring--plane crossings in May, August and November 1995 showed that the edge-on brightness of Saturn's rings is dominated not by the classical A and B rings, but by the narrow, irregular F Ring (Nicholson et al., [1996] Science 272, 509; Bosh & Rivkin [1996] Ibid 272, 518). Located 3500 km exterior to the outer edge of the A ring, and bounded by the small satellites Prometheus and Pandora, the F ring is ~ 50 km wide, optically thin at normal incidence angles, and exhibits a multi-stranded appearance in high resolution Voyager images (Murray et al. [1997] Icarus 129, 304). Occultation observations in 1980/81 and 1989 show a single strand which is well-fitted by a precessing keplerian ellipse with semimajor axis 140209 km and e = 0.0029. A stellar occultation observed by HST on 22 November 1995, just after the solar ring plane crossing and at a terrestrial incidence angle of only 2.7 deg, revealed that the F ring is inclined at an angle of 0.0062 deg to the plane of the main rings (Olkin & Bosh [1996] BAAS, 28, 1125). This non-zero inclination, which corresponds to a vertical amplitude a sin i = 15 km, also manifests itself in the partial eclipse of the F ring by the A ring in the November HST images. By precessing the ring back to the Earth ring plane crossing of 10 August, we find that the curious east-west asymmetry in the brightness of the main rings noted at this time - which is the principal source of uncertainty in the crossing time (Nicholson & French [1997] BAAS 29, 1097) - is apparently due to partial obscuration of the A and B rings by the inclined F ring. By chance, the Earth crossing of 22 May occurred when the line of nodes pointed to the Earth, and no such asymmetry was seen. Photometric models of the edge-on ring brightness should permit us to determine both the thickness and radial optical depth of the F ring, and eventually to refine the ring plane crossing time to within an uncertainty of a few minutes .

  20. Einstein Ring in Distant Universe

    NASA Astrophysics Data System (ADS)

    2005-06-01

    Using ESO's Very Large Telescope, Rémi Cabanac and his European colleagues have discovered an amazing cosmic mirage, known to scientists as an Einstein Ring. This cosmic mirage, dubbed FOR J0332-3557, is seen towards the southern constellation Fornax (the Furnace), and is remarkable on at least two counts. First, it is a bright, almost complete Einstein ring. Second, it is the farthest ever found. ESO PR Photo 20a/05 ESO PR Photo 20a/05 Deep Image of a Region in Fornax (FORS/VLT) [Preview - JPEG: 400 x 434 pix - 60k] [Normal - JPEG: 800 x 867 pix - 276k] [Full Res - JPEG: 1859 x 2015 pix - 3.8M] ESO PR Photo 20b/05 ESO PR Photo 20b/05 Zoom-in on the Newly Found Einstein Ring (FORS/VLT) [Preview - JPEG: 400 x 575 pix - 168k] [Normal - JPEG: 630 x 906 pix - 880k] Caption: ESO PR Photo 20a/05 is a composite image taken in two bands (B and R) with VLT/FORS1 of a small portion of the sky (field-of-view 7x7' or 1/15th of the area of the full moon). The faintest object seen in the image has a magnitude 26, that is, it is 100 million times fainter than what can be observed with the unaided eye. The bright elliptical galaxy on the lower-left quadrant is a dwarf galaxy part of a large nearby cluster in the Fornax constellation. As for all deep images of the sky, this field shows a variety of objects, the brightest ponctual sources being stars from our Galaxy. By far the field is dominated by thousands of faint background galaxies the colours of which are related to the age of their dominant stellar population, their dust content and their distance. The newly found Einstein ring is visible in the top right part of the image. ESO PR Photo 20b/05 zooms-in on the position of the newly found cosmic mirage. ESO PR Photo 20c/05 ESO PR Photo 20c/05 Einstein Ring in Distant Universe (FORS/VLT) [Preview - JPEG: 400 x 584 pix - 104k] [Normal - JPEG: 800 x 1168 pix - 292k] [Full Res - JPEG: 1502 x 2192 pix - 684k] Caption of ESO PR Photo 20c/05: The left image is magnified and centred