Sacral Insufficiency Fractures After Preoperative Chemoradiation for Rectal Cancer: Incidence, Risk Factors, and Clinical Course

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herman, Michael P.; Kopetz, Scott; Bhosale, Priya R.

2009-07-01

Purpose: Sacral insufficiency (SI) fractures can occur as a late side effect of pelvic radiation therapy. Our goal was to determine the incidence, risk factors, and clinical course of SI fractures in patients treated with preoperative chemoradiation for rectal cancer. Materials and Methods: Between 1989 and 2004, 562 patients with non-metastatic rectal adenocarcinoma were treated with preoperative chemoradiation followed by mesorectal excision. The median radiotherapy dose was 45 Gy. The hospital records and radiology reports of these patients were reviewed to identify those with pelvic fractures. Radiology images of patients with pelvic fractures were then reviewed to identify those withmore » SI fractures. Results: Among the 562 patients, 15 had SI fractures. The 3-year actuarial rate of SI fractures was 3.1%. The median time to SI fractures was 17 months (range, 2-34 months). The risk of SI fractures was significantly higher in women compared to men (5.8% vs. 1.6%, p = 0.014), and in whites compared with non-whites (4% vs. 0%, p = 0.037). On multivariate analysis, gender independently predicted for the risk of SI fractures (hazard ratio, 3.25; p = 0.031). Documentation about the presence or absence of pain was available for 13 patients; of these 7 (54%) had symptoms requiring pain medications. The median duration of pain was 22 months. No patient required hospitalization or invasive intervention for pain control. Conclusions: SI fractures were uncommon in patients treated with preoperative chemoradiation for rectal cancer. The risk of SI fractures was significantly higher in women. Most cases of SI fractures can be managed conservatively with pain medications.« less

An unusual stress fracture: Bilateral posterior longitudinal stress fracture of tibia.

PubMed

Malkoc, Melih; Korkmaz, Ozgur; Ormeci, Tugrul; Oltulu, Ismail; Isyar, Mehmet; Mahirogulları, Mahir

2014-01-01

Stress fractures (SF) occur when healthy bone is subjected to cyclic loading, which the normal carrying range capacity is exceeded. Usually, stress fractures occur at the metatarsal bones, calcaneus, proximal or distal tibia and tends to be unilateral. This article presents a 58-year-old male patient with bilateral posterior longitudinal tibial stress fractures. A 58 years old male suffering for persistent left calf pain and decreased walking distance for last one month and after imaging studies posterior longitudinal tibial stress fracture was detected on his left tibia. After six months the patient was admitted to our clinic with the same type of complaints in his right leg. All imaging modalities and blood counts were performed and as a result longitudinal posterior tibial stress fractures were detected on his right tibia. Treatment of tibial stress fracture includes rest and modified activity, followed by a graded return to activity commensurate with bony healing. We have applied the same treatment protocol and our results were acceptable but our follow up time short for this reason our study is restricted for separate stress fractures of the posterior tibia. Although the main localization of tibial stress fractures were unilateral, anterior and transverse pattern, rarely, like in our case, the unusual bilateral posterior localization and longitudinal pattern can be seen. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Epidemiology of metatarsal stress fractures versus tibial and femoral stress fractures during elite training.

PubMed

Finestone, Aharon; Milgrom, Charles; Wolf, Omer; Petrov, Kaloyan; Evans, Rachel; Moran, Daniel

2011-01-01

The training of elite infantry recruits takes a year or more. Stress fractures are known to be endemic in their basic training and the clinical presentation of tibial, femoral, and metatarsal stress fractures are different. Stress fracture incidence during the subsequent progressively more demanding training is not known. The study hypothesis was that after an adaptation period, the incidence of stress fractures during the course of 1 year of elite infantry training would fall in spite of the increasingly demanding training. Seventy-six male elite infantry recruits were followed for the development of stress fractures during a progressively more difficult training program composed of basic training (1 to 14 weeks), advanced training (14 to 26 weeks), and unit training (26 to 52 weeks). Subjects were reviewed regularly and those with clinical suspicion of stress fracture were assessed using bone scan and X-rays. The incidence of stress fractures was 20% during basic training, 14% during advanced training and 23% during unit training. There was a statistically significant difference in the incidence of tibial and femoral stress fractures versus metatarsal stress fractures before and after the completion of phase II training at week 26 (p=0.0001). Seventy-eight percent of the stress fractures during phases I and II training were either tibial or femoral, while 91% of the stress fractures in phase III training were metatarsal. Prior participation in ball sports (p=0.02) and greater tibial length (p=0.05) were protective factors for stress fracture. The study hypothesis that after a period of soldier adaptation, the incidence of stress fractures would decrease in spite of the increasingly demanding elite infantry training was found to be true for tibial and femoral fractures after 6 months of training but not for metatarsal stress fractures. Further studies are required to understand the mechanism of this difference but physicians and others treating stress fractures

Metatarsal stress fractures - aftercare

MedlinePlus

... page: //medlineplus.gov/ency/patientinstructions/000553.htm Metatarsal stress fractures - aftercare To use the sharing features on ... that connect your ankle to your toes. A stress fracture is a break in the bone that ...

Landmarks for Sacral Debridement in Sacral Pressure Sores.

PubMed

Choo, Joshua H; Wilhelmi, Bradon J

2016-03-01

Most cases of sacral osteomyelitis arising in the setting of sacral pressure ulcers require minimal cortical debridement. When faced with advanced bony involvement, the surgeon is often unclear about how much can safely be resected. Unfamiliarity with sacral anatomy can lead to concerns of inadvertent entry into the dural space and compromise of future flap options. A cadaveric study (n = 6), in which a wide posterior dissection of the sacrum, was performed. Relationships of the dural sac to bony landmarks of the posterior pelvis were noted. The termination of the dural sac was found in our study to occur at the junction of S2/S3 vertebral bodies, which was located at a mean distance of 0.38 ± 0.16 cm distal to the inferior-most extent of the posterior superior iliac spine (PSIS). The mean thickness of the posterior table of sacrum at this level was 1.7 cm at the midline and 0.5 cm at the sacral foramina. The PSIS is a reliable landmark for localizing the S2/S3 junction and the termination of the dural sac. Sacral debridement medial to the sacral foramina above the level of PSIS must be conservative whenever possible. If aggressive debridement is necessary above this level, the surgeon must be alert to the possibility of dural involvement.

Complex sacral abscess 8 years after abdominal sacral colpopexy.

PubMed

Collins, Sarah A; Tulikangas, Paul K; LaSala, Christine A; Lind, Lawrence R

2011-08-01

Sacral colpopexy is an effective, durable repair for women with apical vaginal or uterovaginal prolapse. There are few reports of serious complications diagnosed in the remote postoperative period. A 74-year-old woman presented 8 years after undergoing posthysterectomy abdominal sacral colpopexy using polypropylene mesh. Posterior vaginal mesh erosion had been diagnosed several months before presentation. She suffered severe infectious complications including an infected thrombus in the inferior vena cava, sacral osteomyelitis, and a complex abscess with presacral and epidural components. Surgical exploration revealed an abscess cavity surrounding the mesh. Although minor complications commonly occur after sacral colpopexy using abdominal mesh, serious and rare postoperative infectious complications may occur years postoperatively.

Fractures of the Sacrum After Chemoradiation for Rectal Carcinoma: Incidence, Risk Factors, and Radiographic Evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Han Jo; Boland, Patrick J.; Meredith, Dennis S.

Purpose: Sacral insufficiency fractures after adjuvant radiation for rectal carcinoma can present similarly to recurrent disease. As a complication associated with pelvic radiation, it is important to be aware of the incidence and risk factors associated with sacral fractures in the clinical assessment of these patients. Methods and Materials: Between 1998 and 2007, a total of 582 patients with locally advanced rectal carcinoma received adjuvant chemoradiation and surgical excision. Of these, 492 patients had imaging studies available for review. Hospital records and imaging studies from all 492 patients were retrospectively evaluated to identify risk factors associated with developing a sacralmore » insufficiency fracture. Results: With a median follow-up time of 3.5 years, the incidence of sacral fractures was 7.1% (35/492). The 4-year sacral fracture free rate was 0.91. Univariate analysis showed that increasing age ({>=}60 vs. <60 years), female sex, and history of osteoporosis were significantly associated with shorter time to sacral fracture (P=.01, P=.004, P=.001, respectively). There was no significant difference in the time to sacral fracture for patients based on stage, radiotherapy dose, or chemotherapy regimen. Multivariate analysis showed increasing age ({>=}60 vs. <60 years, hazard ratio [HR] = 2.50, 95% confidence interval [CI] = 1.22-5.13, P=.01), female sex (HR = 2.64, CI = 1.29-5.38, P=.008), and history of osteoporosis (HR = 3.23, CI = 1.23-8.50, P=.02) were independent risk factors associated with sacral fracture. Conclusions: Sacral insufficiency fractures after pelvic radiation for rectal carcinoma occur more commonly than previously described. Independent risk factors associated with fracture were osteoporosis, female sex, and age greater than 60 years.« less

Foot and Ankle Stress Fractures in Athletes.

PubMed

Greaser, Michael C

2016-10-01

The incidence of stress fractures in the general athletic population is less than 1%, but may be as high as 15% in runners. Stress fractures of the foot and ankle account for almost half of bone stress injuries in athletes. These injuries occur because of repetitive submaximal stresses on the bone resulting in microfractures, which may coalesce to form complete fractures. Advanced imaging such as MRI and triple-phase bone scans is used to evaluate patients with suspected stress fracture. Low-risk stress fractures are typically treated with rest and protected weight bearing. High-stress fractures more often require surgical treatment. Copyright © 2016 Elsevier Inc. All rights reserved.

Bone stress in runners with tibial stress fracture.

PubMed

Meardon, Stacey A; Willson, John D; Gries, Samantha R; Kernozek, Thomas W; Derrick, Timothy R

2015-11-01

Combinations of smaller bone geometry and greater applied loads may contribute to tibial stress fracture. We examined tibial bone stress, accounting for geometry and applied loads, in runners with stress fracture. 23 runners with a history of tibial stress fracture & 23 matched controls ran over a force platform while 3-D kinematic and kinetic data were collected. An elliptical model of the distal 1/3 tibia cross section was used to estimate stress at 4 locations (anterior, posterior, medial and lateral). Inner and outer radii for the model were obtained from 2 planar x-ray images. Bone stress differences were assessed using two-factor ANOVA (α=0.05). Key contributors to observed stress differences between groups were examined using stepwise regression. Runners with tibial stress fracture experienced greater anterior tension and posterior compression at the distal tibia. Location, but not group, differences in shear stress were observed. Stepwise regression revealed that anterior-posterior outer diameter of the tibia and the sagittal plane bending moment explained >80% of the variance in anterior and posterior bone stress. Runners with tibial stress fracture displayed greater stress anteriorly and posteriorly at the distal tibia. Elevated tibial stress was associated with smaller bone geometry and greater bending moments about the medial-lateral axis of the tibia. Future research needs to identify key running mechanics associated with the sagittal plane bending moment at the distal tibia as well as to identify ways to improve bone geometry in runners in order to better guide preventative and rehabilitative efforts. Copyright © 2015 Elsevier Ltd. All rights reserved.

Tarsal navicular stress fractures: radiographic evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pavlov, H.; Torg, J.S.; Freiberger, R.H.

1983-09-01

Tarsal navicular stress fractures are a potential source of disabling foot pain in physically active individuals. The diagnosis of tarsal navicular stress fracture requires a high index of clinical and radiographic suspicion because the fracture is only rarely evident on routine radiographs or standard tomograms. The radiographic diagnosis of a tarsal navicular stress fracture may require anatomic anteroposterior tomograms or a radionuclide bone scan with plantar views. Radiographic examinations of 23 fractures in 21 patients are evaluated.

Stress fractures: diagnosis, treatment, and prevention.

PubMed

Patel, Deepak S; Roth, Matt; Kapil, Neha

2011-01-01

Stress fractures are common injuries in athletes and military recruits. These injuries occur more commonly in lower extremities than in upper extremities. Stress fractures should be considered in patients who present with tenderness or edema after a recent increase in activity or repeated activity with limited rest. The differential diagnosis varies based on location, but commonly includes tendinopathy, compartment syndrome, and nerve or artery entrapment syndrome. Medial tibial stress syndrome (shin splints) can be distinguished from tibial stress fractures by diffuse tenderness along the length of the posteromedial tibial shaft and a lack of edema. When stress fracture is suspected, plain radiography should be obtained initially and, if negative, may be repeated after two to three weeks for greater accuracy. If an urgent diagnosis is needed, triple-phase bone scintigraphy or magnetic resonance imaging should be considered. Both modalities have a similar sensitivity, but magnetic resonance imaging has greater specificity. Treatment of stress fractures consists of activity modification, including the use of nonweight-bearing crutches if needed for pain relief. Analgesics are appropriate to relieve pain, and pneumatic bracing can be used to facilitate healing. After the pain is resolved and the examination shows improvement, patients may gradually increase their level of activity. Surgical consultation may be appropriate for patients with stress fractures in high-risk locations, nonunion, or recurrent stress fractures. Prevention of stress fractures has been studied in military personnel, but more research is needed in other populations.

[Sacral pressure sores and their treatment].

PubMed

Bielecki, Marek; Skowroński, Rafał; Skowroński, Jan

2006-01-01

Sacral bed sores still present a serious problem in most surgery departments. They occur mainly in elderly patients of limited mobility. The treatment of such sores extends over long periods of time and therefore involves considerable costs. The material consisted of 11 sacral pressure ulcers treated surgically. The sores occurred in 4 severely disabled patients suffering from proximal third femur fractures, 4 patients with traumatic brain injury (treated in the Intensive Care Unit), and 3 patients suffering from bed sores after spinal cord injury. In 6 patients a fasciocutaneous flap was applied to the sores and in 5 cases a pedicled musculocutaneous gluteus maximus flap. The end results were assessed using Seiler's criteria. Complications of the "seroma" type were observed in 3 patients, and in 2 marginal necrosis. In all our patients complete healing was achieved within 2-4 weeks. On analysing our experience to date in surgical treatment of bed sores we are of the opinion that even extensive sacral sores can be covered with unilateral pedicled flaps provided that they are appropriately planned. Deep sores of the 4th degree sometimes with concomitant osteomyelitis require pedicled muscle flaps or in some cases musculocutaneous flaps to improve local circulation. The preparation of the patient for reconstruction surgery is just as important as the operation itself and therefore such preparation should never be neglected.

Risk factors for stress fractures.

PubMed

Bennell, K; Matheson, G; Meeuwisse, W; Brukner, P

1999-08-01

Preventing stress fractures requires knowledge of the risk factors that predispose to this injury. The aetiology of stress fractures is multifactorial, but methodological limitations and expediency often lead to research study designs that evaluate individual risk factors. Intrinsic risk factors include mechanical factors such as bone density, skeletal alignment and body size and composition, physiological factors such as bone turnover rate, flexibility, and muscular strength and endurance, as well as hormonal and nutritional factors. Extrinsic risk factors include mechanical factors such as surface, footwear and external loading as well as physical training parameters. Psychological traits may also play a role in increasing stress fracture risk. Equally important to these types of analyses of individual risk factors is the integration of information to produce a composite picture of risk. The purpose of this paper is to critically appraise the existing literature by evaluating study design and quality, in order to provide a current synopsis of the known scientific information related to stress fracture risk factors. The literature is not fully complete with well conducted studies on this topic, but a great deal of information has accumulated over the past 20 years. Although stress fractures result from repeated loading, the exact contribution of training factors (volume, intensity, surface) has not been clearly established. From what we do know, menstrual disturbances, caloric restriction, lower bone density, muscle weakness and leg length differences are risk factors for stress fracture. Other time-honoured risk factors such as lower extremity alignment have not been shown to be causative even though anecdotal evidence indicates they are likely to play an important role in stress fracture pathogenesis.

Stress fracture of the second proximal phalanx of the foot in teenage athletes: Unrecognized location of stress fracture.

PubMed

Yamaguchi, Satoshi; Taketomi, Shuji; Funakoshi, Yusei; Tsuchiya, Kan; Akagi, Ryuichiro; Kimura, Seiji; Sadamasu, Aya; Ohtori, Seiji

2017-10-01

Adolescent athletes are a high-risk population for stress fractures. We report four cases of stress fractures of the second proximal phalanx, which had not been previously diagnosed as the location of the stress fracture of the foot, in teenage athletes. All fractures were on the plantar side of the proximal phalangeal base, and the oblique images of the plain radiograph clearly depicted the fractures. Notably, three out of the four patients had histories of stress fracture of other locations. While three athletes with acute cases were able to make an early return to play with simple conservative management, the chronic case required surgical treatment for this rare injury. Although a rare injury, it is important that clinicians be aware of this type of stress fracture, as a timely diagnosis can avoid the need for surgical treatment and allow an early return to play.

Stress fractures in elite cross-country athletes.

PubMed

Laker, Scott R; Saint-Phard, Deborah; Tyburski, Mark; Van Dorsten, Brent

2007-04-01

This retrospective and comparative survey investigates an unusual number of stress fractures seen within a Division I college cross-country team. An anonymous questionnaire-designed to observe factors known to increase stress fracture incidence-was distributed to members of the current and previous seasons' teams. Running surface, sleep hours, intake of calcium, and shoe type were among the factors investigated. Eleven lower extremity stress fractures were found in nine athletes. Athletes with stress fractures reported significantly fewer workouts per week on the new track. All other study parameters had no statistically significant effect on stress fractures in these athletes.

Impact of Stress on Anomalous Transport in Fractured Rock

NASA Astrophysics Data System (ADS)

Kang, P. K.; Lei, Q.; Lee, S.; Dentz, M.; Juanes, R.

2016-12-01

Fluid flow and transport in fractured rock controls many natural and engineered processes in the subsurface. However, characterizing flow and transport through fractured media is challenging due to the large heterogeneity of fractured rock properties. In addition to these "static" challenges, geologic fractures are always under significant overburden stress, and changes in the stress state can lead to changes in the fracture's ability to conduct fluids. While confining stress has been shown to impact fluid flow through fractures in a fundamental way, the impact of confining stress on transport through fractured rock remains largely unexplored. The link between anomalous (non-Fickian) transport and confining stress has been shown only recently, at the level of a single rough fracture [1]. Here, we investigate the impact of confining stress on flow and transport through discrete fracture networks. We model geomechanical effects in 2D fractured rock by means of a finite-discrete element method (FEMDEM), which can capture the deformation of matrix blocks, reactivation and propagation of cracks. We implement a joint constitutive model within the FEMDEM framework to simulate the effect of fracture roughness. We apply the model to a fracture network extracted from the geological map of an actual outcrop to obtain the aperture field at different stress conditions (Figure 1). We then simulate fluid flow and particle transport through the stressed fracture networks. We observe that anomalous transport emerges in response to confining stress on the fracture networks, and show that this anomalous behavior can be linked to the stress state of the rock. Finally, we develop an effective transport model that captures the anomalous transport through stressed fractures. Our results point to a heretofore unrecognized link between geomechanics and anomalous transport in discrete fractured networks. [1] P. K. Kang, S. Brown, and R. Juanes, Emergence of anomalous transport in stressed

Safe Zone Quantification of the Third Sacral Segment in Normal and Dysmorphic Sacra.

PubMed

Hwang, John S; Reilly, Mark C; Shaath, Mohammad K; Changoor, Stuart; Eastman, Jonathan; Routt, Milton Lee Chip; Sirkin, Michael S; Adams, Mark R

2018-04-01

To quantify the osseous anatomy of the dysmorphic third sacral segment and assess its ability to accommodate internal fixation. Retrospective chart review of a trauma database. University Level 1 Trauma Center. Fifty-nine patients over the age of 18 with computed tomography scans of the pelvis separated into 2 groups: a group with normal pelvic anatomy and a group with sacral dysmorphism. The sacral osseous area was measured on computed tomography scans in the axial, coronal, and sagittal planes in normal and dysmorphic pelves. These measurements were used to determine the possibility of accommodating a transiliac transsacral screw in the third sacral segment. In the normal group, the S3 coronal transverse width averaged 7.71 mm and the S3 axial transverse width averaged 7.12 mm. The mean S3 cross-sectional area of the normal group was 55.8 mm. The dysmorphic group was found to have a mean S3 coronal transverse width of 9.49 mm, an average S3 axial transverse width of 9.14 mm, and an S3 cross-sectional area of 77.9 mm. The third sacral segment of dysmorphic sacra has a larger osseous pathway available to safely accommodate a transiliac transsacral screw when compared with normal sacra. The S3 segment of dysmorphic sacra can serve as an additional site for screw placement when treating unstable posterior pelvic ring fractures.

High-Risk Stress Fractures: Diagnosis and Management.

PubMed

McInnis, Kelly C; Ramey, Lindsay N

2016-03-01

Stress fractures are common overuse injuries in athletes. They occur during periods of increased training without adequate rest, disrupting normal bone reparative mechanisms. There are a host of intrinsic and extrinsic factors, including biochemical and biomechanical, that put athletes at risk. In most stress fractures, the diagnosis is primarily clinical, with imaging indicated at times, and management focused on symptom-free relative rest with advancement of activity as tolerated. Overall, stress fractures in athletes have an excellent prognosis for return to sport, with little risk of complication. There is a subset of injuries that have a greater risk of fracture progression, delayed healing, and nonunion and are generally more challenging to treat with nonoperative care. Specific locations of high-risk stress fracture include the femoral neck (tension side), patella, anterior tibia, medial malleolus, talus, tarsal navicular, proximal fifth metatarsal, and great toe sesamoids. These sites share a characteristic region of high tensile load and low blood flow. High-risk stress fractures require a more aggressive approach to evaluation, with imaging often necessary, to confirm early and accurate diagnosis and initiate immediate treatment. Treatment consists of nonweight-bearing immobilization, often with a prolonged period away from sport, and a more methodic and careful reintroduction to athletic activity. These stress fractures may require surgical intervention. A high index of suspicion is essential to avoid delayed diagnosis and optimize outcomes in this subset of stress fractures. Copyright © 2016 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Transverse Stress Fracture of the Proximal Patella

PubMed Central

Atsumi, Satoru; Arai, Yuji; Kato, Ko; Nishimura, Akinobu; Nakazora, Shigeto; Nakagawa, Shuji; Ikoma, Kazuya; Fujiwara, Hiroyoshi; Sudo, Akihiro; Kubo, Toshikazu

2016-01-01

Abstract Among stress fractures associated with sports activities, patellar stress fracture is rare. Regarding patella stress fractures, so far only distal transverse or lateral longitudinal fractures have been reported, but there are no reports of transverse fractures occurring in the proximal patella. We describe an extremely rare case of transverse stress fracture of proximal patella in a 9-year-old athlete. A 9-year old boy, who participated in sports (sprints and Kendo) presented with left knee pain without any external injury. In plain radiographs, a fracture line was observed in the proximal 1/3 of the left patella, and a patella stress fracture was diagnosed. For treatment, because 7 months of conservative therapy showed no improvement, internal fixation was carried out using Acutrak screws, and bone union was thus achieved. Three months after the operation, he was able to return to his previous level of athletic sports activity. Regarding the mechanism of onset, it is believed that the causes are longitudinal traction force and patellofemoral contact pressure. On the other hand, the contact region of the patella with the femur changes with the flexion angle of the knee. In the current case, the fracture occurred at a site where the patella was in contact with the femur at a flexion angle of >90°, so it is believed that it occurred as a clinical condition from being subjected to repeated longitudinal traction force and patellofemoral contact pressure at a flexion angle of >90°, during the sports activities of sprints and Kendo. The nonunion of the transverse stress fracture of his proximal patella was successfully treated with internal fixation using Acutrak screws. PMID:26871789

Stress fluctuations in fracture networks from theoretical and numerical models

NASA Astrophysics Data System (ADS)

Davy, P.; Darcel, C.; Mas Ivars, D.; Le Goc, R.

2017-12-01

We analyze the spatial fluctuations of stress in a simple tridimensional model constituted by a population of disc-shaped fractures embedded in an elastic matrix with uniform and isotropic properties. The fluctuations arise from the classical stress enhancement at fracture tips and stress shadowing around fracture centers that are amplified or decreased by the interactions between close-by fractures. The distribution of local stresses is calculated at the elementary mesh scale with the 3DEC numerical program based on the distinct element method. As expected, the stress distributions vary with fracture density, the larger is the density, the wider is the distribution. For freely slipping fractures, it is mainly controlled by the percolation parameter p (i.e., the total volume of spheres surrounding fractures). For stresses smaller than the remote deviatoric stress, the distribution depends only on for the range of density that has been studied. For large stresses, the distribution decreases exponentially when increasing stress, with a characteristic stress that increases with entailing a widening of the stress distribution. We extend the analysis to fractures with plane resistance defined by an elastic shear stiffness ks and a slip Coulomb threshold. A consequence of the fracture plane resistance is to lower the stress perturbation in the surrounding matrix by a factor that depends on the ratio between ks and a fracture-matrix stiffness km mainly dependent on the ratio between Young modulus and fracture size. km is also the ratio between the remote shear stress and the displacement across the fracture plane in the case of freely slipping fractures. A complete analytical derivation of the expressions of the stress perturbations and of the fracture displacements is obtained and checked with numerical simulations. In the limit ks >> km, the stress perturbation tends to 0 and the stress state is spatially uniform. The analysis allows us to quantify the intensity of the

Rare stress fracture: longitudinal fracture of the femur.

PubMed

Pérez González, M; Velázquez Fragua, P; López Miralles, E; Abad Moretón, M M

42-year-old man with pain in the posterolateral region of the right knee that began while he was running. Initially, it was diagnosed by magnetic resonance (MR) as a possible aggressive process (osteosarcoma or Ewing's sarcoma) but with computed tomography it was noted a cortical hypodense linear longitudinal image with a continuous, homogeneous and solid periosteal reaction without clear soft tissue mass that in this patient suggest a longitudinal distal femoral fatigue stress fracture. This type of fracture at this location is very rare. Stress fractures are entities that can be confused with an agressive process. MR iscurrently the most sensitive and specific imaging method for its diagnosis. Copyright © 2017 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

Stress fractures of the foot and ankle.

PubMed

Welck, M J; Hayes, T; Pastides, P; Khan, W; Rudge, B

2017-08-01

Stress fractures occur as a result of microscopic injuries sustained when bone is subjected to repeated submaximal stresses. Overtime, with repeated cycles of loading, accumulation of such injuries can lead to macro-structural failure and frank fracture. There are numerous stress fractures about the foot and ankle of which a trauma and orthopaedic surgeon should be aware. These include: metatarsal, tibia, calcaneus, navicular, fibula, talus, medial malleolus, sesamoid, cuneiform and cuboid. Awareness of these fractures is important as the diagnosis is frequently missed and appropriate treatment delayed. Late identification can be associated with protracted pain and disability, and may predispose to non-union and therefore necessitate operative intervention. This article outlines the epidemiology and risk factors, aetiology, presentation and management of the range of stress fractures in the foot and ankle. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fluid Production Induced Stress Analysis Surrounding an Elliptic Fracture

NASA Astrophysics Data System (ADS)

Pandit, Harshad Rajendra

Hydraulic fracturing is an effective technique used in well stimulation to increase petroleum well production. A combination of multi-stage hydraulic fracturing and horizontal drilling has led to the recent boom in shale gas production which has changed the energy landscape of North America. During the fracking process, highly pressurized mixture of water and proppants (sand and chemicals) is injected into to a crack, which fractures the surrounding rock structure and proppants help in keeping the fracture open. Over a longer period, however, these fractures tend to close due to the difference between the compressive stress exerted by the reservoir on the fracture and the fluid pressure inside the fracture. During production, fluid pressure inside the fracture is reduced further which can accelerate the closure of a fracture. In this thesis, we study the stress distribution around a hydraulic fracture caused by fluid production. It is shown that fluid flow can induce a very high hoop stress near the fracture tip. As the pressure gradient increases stress concentration increases. If a fracture is very thin, the flow induced stress along the fracture decreases, but the stress concentration at the fracture tip increases and become unbounded for an infinitely thin fracture. The result from the present study can be used for studying the fracture closure problem, and ultimately this in turn can lead to the development of better proppants so that prolific well production can be sustained for a long period of time.

Stress Fractures of the Pelvis and Legs in Athletes

PubMed Central

Behrens, Steve B.; Deren, Matthew E.; Matson, Andrew; Fadale, Paul D.; Monchik, Keith O.

2013-01-01

Context: Stress fractures are common injuries in athletes, often difficult to diagnose. A stress fracture is a fatigue-induced fracture of bone caused by repeated applications of stress over time. Evidence Acquisition: PubMed articles published from 1974 to January 2012. Results: Intrinsic and extrinsic factors may predict the risk of stress fractures in athletes, including bone health, training, nutrition, and biomechanical factors. Based on their location, stress fractures may be categorized as low- or high-risk, depending on the likelihood of the injury developing into a complete fracture. Treatment for these injuries varies substantially and must account for the risk level of the fractured bone, the stage of fracture development, and the needs of the patient. High-risk fractures include the anterior tibia, lateral femoral neck, patella, medial malleolus, and femoral head. Low-risk fractures include the posteromedial tibia, fibula, medial femoral shaft, and pelvis. Magnetic resonance is the imaging test of choice for diagnosis. Conclusions: These injuries can lead to substantial lost time from participation. Treatment will vary by fracture location, but most stress fractures will heal with rest and modified weightbearing. Some may require more aggressive intervention, such as prolonged nonweightbearing movement or surgery. Contributing factors should also be addressed prior to return to sports. PMID:24427386

Prevalence of sacral dysmorphia in a prospective trauma population: Implications for a "safe" surgical corridor for sacro-iliac screw placement

PubMed Central

2011-01-01

Background Percutaneous sacro-iliac (SI) screw fixation represents a widely used technique in the management of unstable posterior pelvic ring injuries and sacral fractures. The misplacement of SI-screws under fluoroscopic guidance represents a critical complication for these patients. This study was designed to determine the prevalence of sacral dysmorphia and the radiographic anatomy of surgical S1 and S2 corridors in a representative trauma population. Methods Prospective observational cohort study on a consecutive series of 344 skeletally mature trauma patients of both genders enrolled between January 1, 2007, to September 30, 2007, at a single academic level 1 trauma center. Inclusion criteria included a pelvic CT scan as part of the initial diagnostic trauma work-up. The prevalence of sacral dysmorphia was determined by plain radiographic pelvic films and CT scan analysis. The anatomy of sacral corridors was analyzed on 3 mm reconstruction sections derived from multislice CT scan, in the axial, coronal, and sagittal plane. "Safe" potential surgical corridors at S1 and S2 were calculated based on these measurements. Results Radiographic evidence of sacral dysmorphia was detected in 49 patients (14.5%). The prevalence of sacral dysmorphia was not significantly different between male and female patients (12.2% vs. 19.2%; P = 0.069). In contrast, significant gender-related differences were detected with regard to radiographic analysis of surgical corridors for SI-screw placement, with female trauma patients (n = 99) having significantly narrower corridors at S1 and S2 in all evaluated planes (axial, coronal, sagittal), compared to male counterparts (n = 245; P < 0.01). In addition, the mean S2 body height was higher in dysmorphic compared to normal sacra, albeit without statistical significance (P = 0.06), implying S2 as a safe surgical corridor of choice in patients with sacral dysmorphia. Conclusions These findings emphasize a high prevalence of sacral

Prevalence of sacral dysmorphia in a prospective trauma population: Implications for a "safe" surgical corridor for sacro-iliac screw placement.

PubMed

Hasenboehler, Erik A; Stahel, Philip F; Williams, Allison; Smith, Wade R; Newman, Justin T; Symonds, David L; Morgan, Steven J

2011-05-10

Percutaneous sacro-iliac (SI) screw fixation represents a widely used technique in the management of unstable posterior pelvic ring injuries and sacral fractures. The misplacement of SI-screws under fluoroscopic guidance represents a critical complication for these patients. This study was designed to determine the prevalence of sacral dysmorphia and the radiographic anatomy of surgical S1 and S2 corridors in a representative trauma population. Prospective observational cohort study on a consecutive series of 344 skeletally mature trauma patients of both genders enrolled between January 1, 2007, to September 30, 2007, at a single academic level 1 trauma center. Inclusion criteria included a pelvic CT scan as part of the initial diagnostic trauma work-up. The prevalence of sacral dysmorphia was determined by plain radiographic pelvic films and CT scan analysis. The anatomy of sacral corridors was analyzed on 3 mm reconstruction sections derived from multislice CT scan, in the axial, coronal, and sagittal plane. "Safe" potential surgical corridors at S1 and S2 were calculated based on these measurements. Radiographic evidence of sacral dysmorphia was detected in 49 patients (14.5%). The prevalence of sacral dysmorphia was not significantly different between male and female patients (12.2% vs. 19.2%; P = 0.069). In contrast, significant gender-related differences were detected with regard to radiographic analysis of surgical corridors for SI-screw placement, with female trauma patients (n = 99) having significantly narrower corridors at S1 and S2 in all evaluated planes (axial, coronal, sagittal), compared to male counterparts (n = 245; P < 0.01). In addition, the mean S2 body height was higher in dysmorphic compared to normal sacra, albeit without statistical significance (P = 0.06), implying S2 as a safe surgical corridor of choice in patients with sacral dysmorphia. These findings emphasize a high prevalence of sacral dysmorphia in a representative trauma

Radiosurgery and radiotherapy for sacral tumors.

PubMed

Gibbs, Iris C; Chang, Steven D

2003-08-15

Sacral tumors represent a small subset of spinal lesions and typically include chordomas, metastases, other primary bone tumors, and benign schwannomas. Resection is the standard treatment for many sacral tumors, but many types of sacral lesions have the potential for recurrence after excision. In these cases, adjuvant radiotherapy is often beneficial. Although conventional radiotherapy plays an important role in the management of spinal lesions, the radiation doses required for adequate local control of many sacral lesions generally exceed the tolerance doses of normal tissues, thus limiting its definitive role in the management of sacral tumors. Recent advances in the field of stereotactic radiosurgery have allowed precise targeting of the sacrum. In this report the authors review the use of these two forms of radiation treatment and their role in managing sacral tumors.

Training, Muscle Fatigue, and Stress Fractures

DTIC Science & Technology

1988-07-15

fractures in the lower appendicular skeleton of new recruits. During peacetime, stress fractures are by far the most co~m~n physical injury in the...research program is to study the etiology of the stress fracture lesion, and isolate any aspects of a physical regime which may exacerbate this...34 of remodelLig, to use the model to identify those areas of the cortex at greatest risk of failure, and the activities which accelerate the deleterious

Effectiveness of using a new polyurethane foam multi-layer dressing in the sacral area to prevent the onset of pressure ulcer in the elderly with hip fractures: A pragmatic randomised controlled trial.

PubMed

Forni, Cristiana; D'Alessandro, Fabio; Gallerani, Pina; Genco, Rossana; Bolzon, Andrea; Bombino, Caterina; Mini, Sandra; Rocchegiani, Laura; Notarnicola, Teresa; Vitulli, Arianna; Amodeo, Alfredo; Celli, Guglielmo; Taddia, Patrizia

2018-06-01

Hip fractures in the elderly are a serious problem for the health service due to the high rate of complications. One of these complications is pressure ulcers that, according to the literature, occur in 8.8% to 55% of patients and mainly arise in the sacral area. The present randomised controlled trial tests whether applying a new innovative multi-layer polyurethane foam dressing (ALLEVYN LIFE™), reduces the onset of pressure ulcers in the sacral area. From March to December 2016, 359 fragility hip fracture patients were randomly divided into 2 groups: 182 in the control group and 177 in the experimental group. Pressure ulcers occurred overall in 36 patients (10%): 8 patients (4.5%) in the experimental group compared to 28 (15.4%) in the control group: P = 0.001, relative risk 0.29 (95% CI 0.14-0.61) with NNT of 9 (95% CI 6-21). In the experimental group the onset of pressure ulcers occurred on average on the 6th day compared to the 4th day in the control group (HR 4.4). Using polyurethane foam is effective at reducing the rate of pressure ulcers in the sacrum in elderly patients with hip fracture. The adhesiveness of this device also enables costs to be kept down. © 2018 The Authors. International Wound Journal published by Medicalhelplines.com Inc and John Wiley & Sons Ltd.

Fracture of Rolled Homogeneous Steel Armor (Nucleation Threshold Stress).

DTIC Science & Technology

1980-01-01

AD-AO81 618 ARMY ARMAMENT RESEARCH AND DEVELOPMENT COMMAND ABERD--ETC F/B 19/4 FRACTURE OF ROLLED HOMOGENEOUS STEEL ARMOR (NUCLEATION THRESHOL--ETC(U...ARBRL-MR-02984A QQ FRACTURE OF ROLLED HOMOGENEOUS STEEL ARMOR (NUCLEATION THRESHOLD STRESS) Gerald L Moss Lynn SeamanLy~ S, ,.DTIC S ELECTED January...nucleation stress, Crack threshold stress, Fracture, Fracture stress, Spallation, Armor, Rolled homogeneous steel armor M~ AS$TRACr (Vita ssf -- ebb

Olecranon stress fracture in a weight lifter: a case report

PubMed Central

Rao, P; Rao, S; Navadgi, B

2001-01-01

Stress fractures have been reported in the upper limb of sportspeople involved in upper limb dominated events. Olecranon stress fractures have been cited in baseball pitchers, javelin throwers, and gymnasts. The unusual case of a stress fracture of the olecranon in a young weight lifter is reported here. The minimally displaced stress fracture was treated with tension band and two Kirschner wires. The fracture healed in four months and the patient returned to light sports activity after six months. Key Words: weight lifter; olecranon; elbow; stress fracture PMID:11157469

Anomalous Transport in Natural Fracture Networks Induced by Tectonic Stress

NASA Astrophysics Data System (ADS)

Kang, P. K.; Lei, Q.; Lee, S.; Dentz, M.; Juanes, R.

2017-12-01

Fluid flow and transport in fractured rock controls many natural and engineered processes in the subsurface. However, characterizing flow and transport through fractured media is challenging due to the high uncertainty and large heterogeneity associated with fractured rock properties. In addition to these "static" challenges, geologic fractures are always under significant overburden stress, and changes in the stress state can lead to changes in the fracture's ability to conduct fluids. While confining stress has been shown to impact fluid flow through fractures in a fundamental way, the impact of confining stress on transportthrough fractured rock remains poorly understood. The link between anomalous (non-Fickian) transport and confining stress has been shown, only recently, at the level of a single rough fracture [1]. Here, we investigate the impact of geologic (tectonic) stress on flow and tracer transport through natural fracture networks. We model geomechanical effects in 2D fractured rock by means of a finite-discrete element method (FEMDEM) [2], which can capture the deformation of matrix blocks, reactivation of pre-existing fractures, and propagation of new cracks, upon changes in the stress field. We apply the model to a fracture network extracted from the geological map of an actual rock outcrop to obtain the aperture field at different stress conditions. We then simulate fluid flow and particle transport through the stressed fracture networks. We observe that anomalous transport emerges in response to confining stress on the fracture network, and show that the stress state is a powerful determinant of transport behavior: (1) An anisotropic stress state induces preferential flow paths through shear dilation; (2) An increase in geologic stress increases aperture heterogeneity that induces late-time tailing of particle breakthrough curves. Finally, we develop an effective transport model that captures the anomalous transport through the stressed fracture

Hygrothermomechanical fracture stress criteria for fiber composites with sense-parity

NASA Technical Reports Server (NTRS)

Chamis, C. C.; Ginty, C. A.

1983-01-01

Hygrothermomechanical fracture stress criteria are developed and evaluated for unidirectional composites (plies) with sense-parity. These criteria explicity quantify the individual contributions of applied, hygral and thermal stresses as well as couplings among these stresses. The criteria are for maximum stress, maximum strain, internal friction, work-to-fracture and combined-stress fracture. Predicted results obtained indicate that first ply failure will occur at stress levels lower than those predicted using criteria currently available in the literature. Also, the contribution of the various stress couplings (predictable only by fracture criteria with sense-parity) is significant to first ply failure and attendant fracture modes.

The Effect of Offloading Heels on Sacral Pressure.

PubMed

Al-Majid, Sadeeka; Vuncanon, Barbara; Carlson, Nika; Rakovski, Cyril

2017-09-01

Offloading a patient's heels during supine surgical procedures is a common practice to prevent heel pressure injuries. This practice may increase sacral pressure and jeopardize sacral skin integrity, but prophylactic dressings may help protect sacral skin. The purpose of this study was to examine the effects of offloading the heels and of multilayered silicone foam dressings on sacral pressure. We measured the sacral pressure of 50 healthy volunteers using a pressure-mapping system under four conditions: heels not offloaded and sacral dressing applied, heels offloaded and dressing applied, heels not offloaded and no dressing, and heels offloaded and no dressing. We used linear mixed-effects modeling to compare the effects of these conditions on sacral pressure. Offloading the heels significantly increased sacral pressure (P < .001), whereas the dressing had no effect on sacral pressure (P = .49). Offloading a patient's heels may increase the risk of sacral pressure injuries. Copyright © 2017 AORN, Inc. Published by Elsevier Inc. All rights reserved.

Stress fractures of the foot and ankle in athletes.

PubMed

Mayer, Stephanie W; Joyner, Patrick W; Almekinders, Louis C; Parekh, Selene G

2014-11-01

Stress fractures of the foot and ankle are a common problem encountered by athletes of all levels and ages. These injuries can be difficult to diagnose and may be initially evaluated by all levels of medical personnel. Clinical suspicion should be raised with certain history and physical examination findings. Scientific and review articles were searched through PubMed (1930-2012) with search terms including stress fractures and 1 of the following: foot ankle, medial malleolus, lateral malleolus, calcaneus, talus, metatarsal, cuboid, cuneiform, sesamoid, or athlete. Clinical review. Level 5. Stress fractures of the foot and ankle can be divided into low and high risk based upon their propensity to heal without complication. A wide variety of nonoperative strategies are employed based on the duration of symptoms, type of fracture, and patient factors, such as activity type, desire to return to sport, and compliance. Operative management has proven superior in several high-risk types of stress fractures. Evidence on pharmacotherapy and physiologic therapy such as bone stimulators is evolving. A high index of suspicion for stress fractures is appropriate in many high-risk groups of athletes with lower extremity pain. Proper and timely work-up and treatment is successful in returning these athletes to sport in many cases. Low-risk stress fracture generally requires only activity modification while high-risk stress fracture necessitates more aggressive intervention. The specific treatment of these injuries varies with the location of the stress fracture and the goals of the patient.

Spartan Release Engagement Mechanism (REM) stress and fracture analysis

NASA Technical Reports Server (NTRS)

Marlowe, D. S.; West, E. J.

1984-01-01

The revised stress and fracture analysis of the Spartan REM hardware for current load conditions and mass properties is presented. The stress analysis was performed using a NASTRAN math model of the Spartan REM adapter, base, and payload. Appendix A contains the material properties, loads, and stress analysis of the hardware. The computer output and model description are in Appendix B. Factors of safety used in the stress analysis were 1.4 on tested items and 2.0 on all other items. Fracture analysis of the items considered fracture critical was accomplished using the MSFC Crack Growth Analysis code. Loads and stresses were obtaind from the stress analysis. The fracture analysis notes are located in Appendix A and the computer output in Appendix B. All items analyzed met design and fracture criteria.

Stress fractures: pathophysiology, clinical presentation, imaging features, and treatment options.

PubMed

Matcuk, George R; Mahanty, Scott R; Skalski, Matthew R; Patel, Dakshesh B; White, Eric A; Gottsegen, Christopher J

2016-08-01

Stress fracture, in its most inclusive description, includes both fatigue and insufficiency fracture. Fatigue fractures, sometimes equated with the term "stress fractures," are most common in runners and other athletes and typically occur in the lower extremities. These fractures are the result of abnormal, cyclical loading on normal bone leading to local cortical resorption and fracture. Insufficiency fractures are common in elderly populations, secondary to osteoporosis, and are typically located in and around the pelvis. They are a result of normal or traumatic loading on abnormal bone. Subchondral insufficiency fractures of the hip or knee may cause acute pain that may present in the emergency setting. Medial tibial stress syndrome is a type of stress injury of the tibia related to activity and is a clinical syndrome encompassing a range of injuries from stress edema to frank-displaced fracture. Atypical subtrochanteric femoral fracture associated with long-term bisphosphonate therapy is also a recently discovered entity that needs early recognition to prevent progression to a complete fracture. Imaging recommendations for evaluation of stress fractures include initial plain radiographs followed, if necessary, by magnetic resonance imaging (MRI), which is preferred over computed tomography (CT) and bone scintigraphy. Radiographs are the first-line modality and may reveal linear sclerosis and periosteal reaction prior to the development of a frank fracture. MRI is highly sensitive with findings ranging from periosteal edema to bone marrow and intracortical signal abnormality. Additionally, a brief description of relevant clinical management of stress fractures is included.

Lower thoracic rib stress fractures in baseball pitchers.

PubMed

Gerrie, Brayden J; Harris, Joshua D; Lintner, David M; McCulloch, Patrick C

2016-01-01

Stress fractures of the first rib on the dominant throwing side are well-described in baseball pitchers; however, lower thoracic rib fractures are not commonly recognized. While common in other sports such as rowing, there is scant literature on these injuries in baseball. Intercostal muscle strains are commonly diagnosed in baseball pitchers and have a nearly identical presentation but also a highly variable healing time. The diagnosis of a rib stress fracture can predict a more protracted recovery. This case series presents two collegiate baseball pitchers on one team during the same season who were originally diagnosed with intercostal muscle strains, which following magnetic resonance imaging (MRI) were found to have actually sustained lower thoracic rib stress fractures. The first sustained a stress fracture of the posterior aspect of the right 8th rib on the dominant arm side, while the second presented with a left-sided 10th rib stress fracture on the nondominant arm side. In both cases, MRI was used to visualize the fractures as plain radiographs are insensitive and commonly negative early in patient presentation. Patients were treated with activity modification, and symptomatic management for 4-6 weeks with a graduated return to throwing and competition by 8-10 weeks. The repetitive high stresses incurred by pitching may cause either dominant or nondominant rib stress fractures and this should be included in the differential diagnosis of thoracic injuries in throwers. It is especially important that athletic trainers and team physicians consider this diagnosis, as rib fractures may have a protracted course and delayed return to play. Additionally, using the appropriate imaging techniques to establish an accurate diagnosis can help inform return-to-play decisions, which have important practical applications in baseball, such as roster management and eligibility.

Stress Fractures of the Foot and Ankle in Athletes

PubMed Central

Mayer, Stephanie W.; Joyner, Patrick W.; Almekinders, Louis C.; Parekh, Selene G.

2014-01-01

Context: Stress fractures of the foot and ankle are a common problem encountered by athletes of all levels and ages. These injuries can be difficult to diagnose and may be initially evaluated by all levels of medical personnel. Clinical suspicion should be raised with certain history and physical examination findings. Evidence Acquisition: Scientific and review articles were searched through PubMed (1930-2012) with search terms including stress fractures and 1 of the following: foot ankle, medial malleolus, lateral malleolus, calcaneus, talus, metatarsal, cuboid, cuneiform, sesamoid, or athlete. Study Design: Clinical review. Level of Evidence: Level 5. Results: Stress fractures of the foot and ankle can be divided into low and high risk based upon their propensity to heal without complication. A wide variety of nonoperative strategies are employed based on the duration of symptoms, type of fracture, and patient factors, such as activity type, desire to return to sport, and compliance. Operative management has proven superior in several high-risk types of stress fractures. Evidence on pharmacotherapy and physiologic therapy such as bone stimulators is evolving. Conclusion: A high index of suspicion for stress fractures is appropriate in many high-risk groups of athletes with lower extremity pain. Proper and timely work-up and treatment is successful in returning these athletes to sport in many cases. Low-risk stress fracture generally requires only activity modification while high-risk stress fracture necessitates more aggressive intervention. The specific treatment of these injuries varies with the location of the stress fracture and the goals of the patient. PMID:25364480

Influence of fracture extension on in-situ stress in tight reservoir

NASA Astrophysics Data System (ADS)

Zhang, Yongping; Wei, Xu; Zhang, Ye; Xing, Libo; Xu, Jianjun

2018-01-01

Currently, hydraulic fracturing is an important way to develop low permeability reservoirs. The fractures produced during the fracturing process are the main influencing factors of changing in-situ stress. In this paper, the influence of fracture extension on in-situ stress is studied by establishing a mathematical model to describe the relationship between fracture length and in-situ stress. The results show that the growth rate gradually decreases after the fracture reaches a certain length with the increase of fracturing time; the continuous extension of the fracture is the main factor to change the in-situ stress. In order to reduce the impact on the subsequent fracture extension due to the changing of in-situ stress, controlling fracturing time and fracture length without affecting the stimulated reservoir effect is an important way. The results presented in this study can effectively reduce the impact of changing of in-situ stress on subsequent fracturing construction.

Correlation Between Fracture Network Properties and Stress Variability in Geological Media

NASA Astrophysics Data System (ADS)

Lei, Qinghua; Gao, Ke

2018-05-01

We quantitatively investigate the stress variability in fractured geological media under tectonic stresses. The fracture systems studied include synthetic fracture networks following power law length scaling and natural fracture patterns based on outcrop mapping. The stress field is derived from a finite-discrete element model, and its variability is analyzed using a set of mathematical formulations that honor the tensorial nature of stress data. We show that local stress perturbation, quantified by the Euclidean distance of a local stress tensor to the mean stress tensor, has a positive, linear correlation with local fracture intensity, defined as the total fracture length per unit area within a local sampling window. We also evaluate the stress dispersion of the entire stress field using the effective variance, that is, a scalar-valued measure of the overall stress variability. The results show that a well-connected fracture system under a critically stressed state exhibits strong local and global stress variabilities.

A study on difference and importance of sacral slope and pelvic sacral angle that affect lumbar curvature.

PubMed

Choi, Seyoung; Lee, Minsun; Kwon, Byongan

2014-01-01

Individual pelvic sacral angle was measured, compared and analyzed for the 6 male and female adults who were diagnosed with lumbar spinal stenosis, foraminal stenosis and mild spondylolisthesis in accordance with spinal parameters, pelvic parameters and occlusion state of sacroiliac joint presented by the author of this thesis based on the fact that the degree of lumbar excessive lordosis that was one of the causes for lumbar pain was determined by sacral slope. The measured values were compared with the standard values of the average normal range from 20 s to 40 s of normal Koreans stated in the study on the change in lumbar lordosis angle, lumbosacral angle and sacral slope in accordance with the age by Oh et al. [5] and sacral slope and pelvic sacral slope of each individual of the subjects for measurement were compared. Comparing the difference between the two tilt angles possessed by an individual is a comparison to determine how much the sacroiliac joint connecting pelvis and sacral vertebrae compensated and corrected the sacral vertebrae slope by pelvic tilt under the condition of synarthrodial joint.Under the condition that the location conforming to the line in which the sagittal line of gravity connects with pelvic ASIS and pubic pubic tuberele is the neutral location of pelvic tilt, sacral slope being greater than pelvic sacral slope means pelvic anterior tilting, whereas sacral slope being smaller than pelvic sacral slope means pelvic posterior tilting. On that account, male B, female A and female C had a pelvic posterior tilting of 16 degrees, 1 degree and 5 degrees respectively, whereas male A, male C and female B had a pelvic anterior tilting of 3 degrees, 9 degrees and 4 degrees respectively. In addition, the 6 patients the values of lumbar lordosis angle, lumbosacral angle and sacral slope that were almost twice as much as the normal standard values of Koreans. It is believed that this is because the pelvic sacral slope maintaining an angle that is

Analysis of stress fractures in athletes based on our clinical experience

PubMed Central

Iwamoto, Jun; Sato, Yoshihiro; Takeda, Tsuyoshi; Matsumoto, Hideo

2011-01-01

AIM: To analyze stress fractures in athletes based on experience from our sports medicine clinic. METHODS: We investigated the association between stress fractures and age, sex, sports level, sports activity, and skeletal site in athletes seen at our sports medicine clinic between September 1991 and April 2009. Stress fractures of the pars interarticularis were excluded from this analysis. RESULTS: During this period (18 years and 8 mo), 14276 patients (9215 males and 5061 females) consulted our clinic because of sports-related injuries, and 263 patients (1.8%) [171 males (1.9%) and 92 females (1.8%)] sustained stress fractures. The average age of the patients with stress fractures was 20.2 years (range 10-46 years); 112 patients (42.6%) were 15-19 years of age and 90 (34.2%) were 20-24 years of age. Altogether, 90 patients (34.2%) were active at a high recreational level and 173 (65.8%) at a competitive level. The highest proportion of stress fractures was seen in basketball athletes (21.3%), followed by baseball (13.7%), track and field (11.4%), rowing (9.5%), soccer (8.4%), aerobics (5.3%), and classical ballet (4.9%). The most common sites of stress fractures in these patients were the tibia (44.1%), followed by the rib (14.1%), metatarsal bone (12.9%), ulnar olecranon (8.7%) and pelvis (8.4%). The sites of the stress fractures varied from sport to sport. The ulnar olecranon was the most common stress fracture site in baseball players, and the rib was the most common in rowers. Basketball and classical ballet athletes predominantly sustained stress fractures of the tibia and metatarsal bone. Track and field and soccer athletes predominantly sustained stress fractures of the tibia and pubic bone. Aerobics athletes predominantly sustained stress fractures of the tibia. Middle and long distance female runners who sustained multiple stress fractures had the female athlete triad. CONCLUSION: The results of this analysis showed that stress fractures were seen in high

Percutaneous cannulated screw fixation of sacral fractures and sacroiliac joint disruptions with CT-controlled guidewires performed by interventionalists: single center experience in treating posterior pelvic instability.

PubMed

Fischer, Sebastian; Vogl, Thomas J; Marzi, Ingo; Zangos, Stephan; Wichmann, Julian L; Scholtz, Jan-Erik; Mack, Martin G; Schmidt, Sven; Eichler, Katrin

2015-02-01

The purpose of our study was to evaluate minimally invasive sacroiliac screw fixation for treatment of posterior pelvic instability with the help of CT controlled guidewires, assess its accuracy, safety and effectiveness, and discuss potential pitfalls. 100 guidewires and hollow titan screws were inserted in 38 patients (49.6±19.5 years) suffering from 35 sacral fractures and/or 16 sacroiliac joint disruptions due to 33 (poly-)traumatic, 2 osteoporotic and 1 post-infectious conditions. The guidewire and screw positions were analyzed in multiplanar reconstructions. The mean minimal distance between guidewire and adjacent neural foramina was 4.5±2.01mm, with a distinctly higher precision in S1 than S2. Eight guidewires showed cortical contacts, resulting in a total of 2% mismatched screws with subsequent wall violation. The fracture gaps were reduced from 3.6±0.53mm to 1.2±0.54mm. During follow-up 3 cases of minor iatrogenic sacral impaction (<5mm) due to the bolting and 2 cases of screw loosening were observed. Interventional time was 84.0min with a mean of 2.63 screws per patient whilst acquiring a mean of 93.7 interventional CT-images (DLP 336.7mGycm). The treatment of posterior pelvic instability with a guidewire-based screw insertion technique under CT-imaging results in a very high accuracy and efficacy with a low complication rate. Careful attention should be drawn to radiation levels. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Medial malleolar stress fracture secondary to chronic ankle impingement.

PubMed

Jowett, Andrew J L; Birks, Christopher L; Blackney, Mark C

2008-07-01

Medial malleolar stress fractures are uncommon even in the sporting population. We believe that stress fractures of the medial malleolus may be the end stage of chronic anteromedial ankle impingement in elite running and jumping athletes. We present five cases of elite athletes who presented to our institution with stress fractures of the medial malleolus over a 3-year period (2004 to 2007). In each case preoperative imaging revealed an anteromedial bony spur on the tibia. All fractures were internally fixed and at the same sitting had arthroscopic debridement of the bony spur. All fractures united without further intervention, average time to union was 10.2 (range, 6 to 16) weeks. At most recent review (average, 18 months; range, 8 to 37 months), all patients had resumed sporting activity to their previous level. No patient had suffered a recurrent fracture of the medial malleolus. We believe this region of impingement to be important in the development of the stress fracture and should be addressed at the time of fracture fixation.

Lower limb stress fractures in sport: Optimising their management and outcome

PubMed Central

Robertson, Greg A J; Wood, Alexander M

2017-01-01

Stress fractures in sport are becoming increasing more common, comprising up to 10% of all of sporting injuries. Around 90% of such injuries are located in the lower limb. This articles aims to define the optimal management of lower limb stress fractures in the athlete, with a view to maximise return rates and minimise return times to sport. Treatment planning of this condition is specific to the location of the injury. However, there remains a clear division of stress fractures by “high” and “low” risk. “Low risk” stress fractures are those with a low probability of fracture propagation, delayed union, or non-union, and so can be managed reliably with rest and exercise limitation. These include stress fractures of the Postero-Medial Tibial Diaphysis, Metatarsal Shafts, Distal Fibula, Medial Femoral Neck, Femoral Shaft and Calcaneus. “High risk” stress fractures, in contrast, have increased rates of fracture propagation, displacement, delayed and non-union, and so require immediate cessation of activity, with orthopaedic referral, to assess the need for surgical intervention. These include stress fractures of the Anterior Tibial Diaphysis, Fifth Metatarsal Base, Medial Malleolus, Lateral Femoral Neck, Tarsal Navicular and Great Toe Sesamoids. In order to establish the optimal methods for managing these injuries, we present and review the current evidence which guides the treatment of stress fractures in athletes. From this, we note an increased role for surgical management of certain high risk stress fractures to improve return times and rates to sport. Following this, key recommendations are provided for the management of the common stress fracture types seen in the athlete. Five case reports are also presented to illustrate the application of sport-focussed lower limb stress fracture treatment in the clinical setting. PMID:28361017

Stress Rupture Fracture Model and Microstructure Evolution for Waspaloy

NASA Astrophysics Data System (ADS)

Yao, Zhihao; Zhang, Maicang; Dong, Jianxin

2013-07-01

Stress rupture behavior and microstructure evolution of nickel-based superalloy Waspaloy specimens from tenon teeth of an as-received 60,000-hour service-exposed gas turbine disk were studied between 923 K and 1088 K (650 °C and 815 °C) under initial applied stresses varying from 150 to 840 MPa. Good microstructure stability and performance were verified for this turbine disk prior to stress rupture testing. Microstructure instability, such as the coarsening and dissolution of γ' precipitates at the varying test conditions, was observed to be increased with temperature and reduced stress. Little microstructure variation was observed at 923 K (650 °C). Only secondary γ' instability occurred at 973 K (700 °C). Four fracture mechanisms were obtained. Transgranular creep fracture was exhibited up to 923 K (650 °C) and at high stress. A mixed mode of transgranular and intergranular creep fracture occurred with reduced stress as a transition to intergranular creep fracture (ICF) at low stress. ICF was dominated by grain boundary sliding at low temperature and by the nucleation and growth of grain boundary cavities due to microstructure instability at high temperature. The fracture mechanism map and microstructure-related fracture model were constructed. Residual lifetime was also evaluated by the Larson-Miller parameter method.

Bilateral femoral neck stress fractures in a fire academy student.

PubMed

Wright, Russell C; Salzman, Garrett A; Yacoubian, Stephan V; Yacoubian, Shahan V

2010-10-11

Unilateral femoral neck stress fractures are well documented in active patients; however, the risk of a subsequent contralateral stress fracture remains unknown in patients who continue to be active. This article describes a 24-year-old male fire academy student who sustained a left femoral neck stress fracture, followed approximately 11 months later by a right femoral neck stress fracture, both of which went on to completely displace. A review of the index radiographs of each hip from outside institutions revealed femoral neck stress fractures that went undiagnosed until they displaced. The patient was referred to our institution and underwent closed reduction and internal fixation using cannulated screws in both cases. A full endocrine evaluation was performed in the following weeks and proved unremarkable. Although it is difficult to extrapolate the results from 1 patient beyond the case studied, there is cause for concern in patients who remain active following femoral neck stress fractures. Our case highlights the significance of obtaining a complete and thorough medical history on physical examination and appropriately counseling patients regarding activity level. Until further research explores this possible relationship, physicians evaluating patients with a history of a stress fracture are encouraged to be vigilant of subsequent contralateral fractures and educate patients of this potentially avoidable injury. Copyright 2010, SLACK Incorporated.

Stress fracture of ulna due to excessive push-ups.

PubMed

Meena, Sanjay; Rastogi, Devarshi; Solanki, Bipin; Chowdhury, Buddhadev

2014-01-01

Stress fractures are most common in the weight-bearing bones of the lower extremities and spine, but are rarely found in non-weight-bearing bones of the body. Stress fracture of the ulna is extremely rare. We report a case of complete stress fracture of ulna caused due to excessive push ups in a young athlete. Conservative management was successful in healing of fracture and returning this patient back to his previous activity level. Physician should have high index of suspicion, whenever they encounter a young athlete complaining of forearm pain.

Women with previous stress fractures show reduced bone material strength

PubMed Central

Duarte Sosa, Daysi; Fink Eriksen, Erik

2016-01-01

Background and purpose — Bone fragility is determined by bone mass, bone architecture, and the material properties of bone. Microindentation has been introduced as a measurement method that reflects bone material properties. The pathogenesis of underlying stress fractures, in particular the role of impaired bone material properties, is still poorly understood. Based on the hypothesis that impaired bone material strength might play a role in the development of stress fractures, we used microindentation in patients with stress fractures and in controls. Patients and methods — We measured bone material strength index (BMSi) by microindentation in 30 women with previous stress fractures and in 30 normal controls. Bone mineral density by DXA and levels of the bone markers C-terminal cross-linking telopeptide of type-1 collagen (CTX) and N-terminal propeptide of type-1 procollagen (P1NP) were also determined. Results — Mean BMSi in stress fracture patients was significantly lower than in the controls (SD 72 (8.7) vs. 77 (7.2); p = 0.02). The fracture subjects also had a significantly lower mean bone mineral density (BMD) than the controls (0.9 (0.02) vs. 1.0 (0.06); p = 0.03). Bone turnover—as reflected in serum levels of the bone marker CTX—was similar in both groups, while P1NP levels were significantly higher in the women with stress fractures (55 μg/L vs. 42 μg/L; p = 0.03). There was no correlation between BMSi and BMD or bone turnover. Interpretation — BMSi was inferior in patients with previous stress fracture, but was unrelated to BMD and bone turnover. The lower values of BMSi in patients with previous stress fracture combined with a lower BMD may contribute to the increased propensity to develop stress fractures in these patients. PMID:27321443

Polyaxial stress-dependent permeability of a three-dimensional fractured rock layer

NASA Astrophysics Data System (ADS)

Lei, Qinghua; Wang, Xiaoguang; Xiang, Jiansheng; Latham, John-Paul

2017-12-01

A study about the influence of polyaxial (true-triaxial) stresses on the permeability of a three-dimensional (3D) fractured rock layer is presented. The 3D fracture system is constructed by extruding a two-dimensional (2D) outcrop pattern of a limestone bed that exhibits a ladder structure consisting of a "through-going" joint set abutted by later-stage short fractures. Geomechanical behaviour of the 3D fractured rock in response to in-situ stresses is modelled by the finite-discrete element method, which can capture the deformation of matrix blocks, variation of stress fields, reactivation of pre-existing rough fractures and propagation of new cracks. A series of numerical simulations is designed to load the fractured rock using various polyaxial in-situ stresses and the stress-dependent flow properties are further calculated. The fractured layer tends to exhibit stronger flow localisation and higher equivalent permeability as the far-field stress ratio is increased and the stress field is rotated such that fractures are preferentially oriented for shearing. The shear dilation of pre-existing fractures has dominant effects on flow localisation in the system, while the propagation of new fractures has minor impacts. The role of the overburden stress suggests that the conventional 2D analysis that neglects the effect of the out-of-plane stress (perpendicular to the bedding interface) may provide indicative approximations but not fully capture the polyaxial stress-dependent fracture network behaviour. The results of this study have important implications for understanding the heterogeneous flow of geological fluids (e.g. groundwater, petroleum) in subsurface and upscaling permeability for large-scale assessments.

Genetic predisposition for femoral neck stress fractures in military conscripts.

PubMed

Korvala, Johanna; Hartikka, Heini; Pihlajamäki, Harri; Solovieva, Svetlana; Ruohola, Juha-Petri; Sahi, Timo; Barral, Sandra; Ott, Jürg; Ala-Kokko, Leena; Männikkö, Minna

2010-10-21

Stress fractures are a significant problem among athletes and soldiers and may result in devastating complications or even permanent handicap. Genetic factors may increase the risk, but no major susceptibility genes have been identified. The purpose of this study was to search for possible genetic factors predisposing military conscripts to femoral neck stress fractures. Eight genes involved in bone metabolism or pathology (COL1A1, COL1A2, OPG, ESR1, VDR, CTR, LRP5, IL-6) were examined in 72 military conscripts with a femoral neck stress fracture and 120 controls. The risk of femoral neck stress fracture was significantly higher in subjects with low weight and body mass index (BMI). An interaction between the CTR (rs1801197) minor allele C and the VDR C-A haplotype was observed, and subjects lacking the C allele in CTR and/or the C-A haplotype in VDR had a 3-fold higher risk of stress fracture than subjects carrying both (OR = 3.22, 95% CI 1.38-7.49, p = 0.007). In addition, the LRP5 haplotype A-G-G-C alone and in combination with the VDR haplotype C-A was associated with stress fractures through reduced body weight and BMI. Our findings suggest that genetic factors play a role in the development of stress fractures in individuals subjected to heavy exercise and mechanical loading. The present results can be applied to the design of future studies that will further elucidate the genetics of stress fractures.

Genetic predisposition for femoral neck stress fractures in military conscripts

PubMed Central

2010-01-01

Background Stress fractures are a significant problem among athletes and soldiers and may result in devastating complications or even permanent handicap. Genetic factors may increase the risk, but no major susceptibility genes have been identified. The purpose of this study was to search for possible genetic factors predisposing military conscripts to femoral neck stress fractures. Results Eight genes involved in bone metabolism or pathology (COL1A1, COL1A2, OPG, ESR1, VDR, CTR, LRP5, IL-6) were examined in 72 military conscripts with a femoral neck stress fracture and 120 controls. The risk of femoral neck stress fracture was significantly higher in subjects with low weight and body mass index (BMI). An interaction between the CTR (rs1801197) minor allele C and the VDR C-A haplotype was observed, and subjects lacking the C allele in CTR and/or the C-A haplotype in VDR had a 3-fold higher risk of stress fracture than subjects carrying both (OR = 3.22, 95% CI 1.38-7.49, p = 0.007). In addition, the LRP5 haplotype A-G-G-C alone and in combination with the VDR haplotype C-A was associated with stress fractures through reduced body weight and BMI. Conclusions Our findings suggest that genetic factors play a role in the development of stress fractures in individuals subjected to heavy exercise and mechanical loading. The present results can be applied to the design of future studies that will further elucidate the genetics of stress fractures. PMID:20961463

Bilateral femoral supracondylar stress fractures in a cross country runner.

PubMed

Ross, Kate; Fahey, Mark

2008-08-01

Several high-risk factors lead to stress fractures. They include excessive training in athletes leading to overuse injuries, nutritional deficiencies, and endocrine disorders. While stress fractures are common, bilateral stress fractures are rarely seen. Few cases have been reported of bilateral femoral stress fractures in young athletes. This article presents a case of a 14-year-old cross country runner with a bilateral femoral supracondylar stress fracture. He presented with bilateral supracondylar stress fractures from running. The patient followed a strict vegan diet, but his parents stated that, to their knowledge, he was getting adequate protein and calcium. Treatment consisted of decreased activity to pain-free levels with acetaminophen for pain. Low-impact conditioning such as swimming and bicycling was allowed. Hamstring and quadricep stretching was suggested. Nutritional consultation was obtained to ensure appropriate nutrition on a vegan diet. At 1-month follow-up, he was pain free and allowed to proceed with a gradual return to running activities. In this case, the onset of a new workout routine was intolerable for this patient's low bone density, causing insufficiency fractures. Appropriate vegan diets were not associated with stress fracture in our literature review. He may have had an inadequate diet prior to this injury. As in this case, full recovery can be made after this rest period, and the patient may return to his or her original activity safely. In young athletes, diet and nutrition must be kept in mind.

Prevalence and clinical features of sports-related lumbosacral stress injuries in the young.

PubMed

Kaneko, Hideto; Murakami, Mototsune; Nishizawa, Kazuya

2017-05-01

Stress injuries (stress fractures and stress reactions) of the lumbosacral region are one of the causes of sports-related lower back pain in young individuals. These injuries can be detected by bone marrow edema lesion on MRI. However, little is known about the prevalence and clinical features of early stage lumbosacral stress injuries. This study aimed to evaluate the epidemiology of lumbosacral stress injuries. A total of 312 patients (under 18 years of age) who complained of sports-related lower back pain that had lasted for ≥7 days underwent magnetic resonance imaging (MRI) scans. We reviewed patients' records retrospectively. MRI showed that 33.0% of the patients had lumbar stress injuries and 1.6% had sacral stress injuries. Lumbar stress injuries were more common in males than in females and were found in 30% of 13- to 18-year-old patients. About 50% of the patients that participated in soccer or track and field were diagnosed with lumbar stress injuries. No clinical patterns in the frequencies of sacral stress injuries were detected due to the low number of patients that suffered this type of injury. Plain radiography is rarely able to detect the early stage lesions associated with lumbosacral stress injuries, but such lesions can be detected in the caudal-ventral region of the pars interarticularis on sagittal computed tomography scans. Thirty-three percent of young patients that complained of sports-related lower back pain for ≥7 days had lumbar stress injuries, while 1.6% of them had sacral stress injuries. Clinicians should be aware of the existence of these injuries. MRI is useful for diagnosing lumbosacral stress injuries.

kISMET: Stress and fracture characterization in a deep mine

NASA Astrophysics Data System (ADS)

Oldenburg, C. M.; Dobson, P. F.; Daley, T. M.; Birkholzer, J. T.; Cook, P. J.; Ajo Franklin, J. B.; Rutqvist, J.; Siler, D.; Kneafsey, T. J.; Nakagawa, S.; Wu, Y.; Guglielmi, Y.; Ulrich, C.; Marchesini, P.; Wang, H. F.; Haimson, B. C.; Sone, H.; Vigilante, P.; Roggenthen, W.; Doe, T.; Lee, M.; Mattson, E.; Huang, H.; Johnson, T. C.; Morris, J.; White, J. A.; Johnson, P. A.; Coblentz, D. D.; Heise, J.

2016-12-01

We are developing a community facility called kISMET (permeability (k) and Induced Seismicity Management for Energy Technologies) at the Sanford Underground Research Facility (SURF) in Lead, SD. The purpose of kISMET is to investigate stress and the effects of rock fabric on hydraulic fracturing. Although findings from kISMET may have broad applications that inform stress and fracturing in anisotropic rock, results will be most applicable to improving control of hydraulic fracturing for enhanced geothermal systems (EGS) in crystalline rock. At the kISMET site on the 4850 ft (1480 m depth) level of SURF, we have drilled and cored an array of nearly vertical boreholes in Precambrian phyllite. The array consists of four 50-m deep monitoring boreholes surrounding one 100-m deep borehole forming a 6 m-wide five-spot pattern at a depth of 1530 m. Previous investigations of the stress field at SURF suggest that the principal stress s1 is nearly vertical. By aligning the kISMET boreholes approximately with σ1, fractures created in the center borehole should in theory be perpendicular to σ3, the least principal horizontal stress. But the phyllite at kISMET has a strong fabric (foliation) that could influence fracturing. Stress measurements and stimulation using hydraulic fracturing will be carried out in the center borehole using a straddle packer and high-pressure pump. We will use an impression packer and image logs after stress testing and stimulation to determine fracture orientation and extent at the center borehole. In order to study the control of stress, rock fabric, and stimulation approach on size, aperture, and orientation of hydraulic fractures, we will carefully monitor the stress measurements and stimulation. For example, we will use continuous active source seismic (CASSM) in two of the monitoring boreholes to measure changes in seismic-wave velocity as water fills the fracture. Second, near real-time electrical resistance tomography (ERT) will be used in

Triangular osteosynthesis of vertically unstable sacrum fractures: a new concept allowing early weight-bearing.

PubMed

Schildhauer, T A; Josten, Ch; Muhr, G

2006-01-01

Presentation of a new triangular osteosynthesis technique that permits early weight-bearing in vertically unstable sacral fractures. : Retrospective evaluation of a consecutive series. Level I trauma center. Thirty-four patients, twenty-eight of whom were poly-traumatized, all with vertically unstable sacral fractures. This group included eight women and twenty-six men, with a mean age of thirty-five years. Average time between trauma and definite operation was thirteen days (range 0 to 28 days). All patients underwent triangular osteosynthesis using a combination of a vertical vertebro-pelvic distraction osteosynthesis (pedicle screw system) and a transverse fixation of the sacrum fracture with either iliosacral screws or trans-sacral plating. Immediate postoperative weight-bearing was permitted postoperatively. Nineteen patients were treated with early progressive weight-bearing and advanced to full weight-bearing, on average, after twenty-three days (range 8 to 70 days). Three of the thirty-four patients (9 percent) experienced loosening of hardware, including two patients (6 percent) who required secondary intervention because of loss of the original reduction. Further complications included one pulmonary embolism (3 percent), one iatrogenic nerve lesion (3 percent), one wound necrosis (3 percent), and two local infections (6 percent). Triangular osteosynthesis is a demanding procedure that can be performed on vertically unstable sacral fractures to allow early progressive weight-bearing with an acceptable complication rate.

Magnetic resonance imaging in stress fractures and shin splints.

PubMed

Aoki, Yoshimitsu; Yasuda, Kazunori; Tohyama, Harukazu; Ito, Hirokazu; Minami, Akio

2004-04-01

The purpose of the current study was to determine whether stress fractures and shin splints could be discriminated with MRI in the early phase. Twenty-two athletes, who had pain in the middle or distal part of their leg during or after sports activity, were evaluated with radiographs and MRI scans. Stress fractures were diagnosed when consecutive radiographs showed local periosteal reaction or a fracture line, and shin splints were diagnosed in all the other cases. In all eight patients with stress fractures, an abnormally wide high signal in the localized bone marrow was the most detectable in the coronal fat-suppressed MRI scan. In 11 patients with shin splints, the coronal fat-suppressed MRI scans showed a linear abnormally high signal along the medial posterior surface of the tibia, and in seven patients with shin splints, the MRI scans showed a linear abnormally high signal along the medial bone marrow. No MRI scans of shin splints showed an abnormally wide high signal in the bone marrow as observed on MRI scans of stress fractures. This study showed that fat-suppressed MRI is useful for discrimination between stress fracture and shin splints before radiographs show a detectable periosteal reaction in the tibia.

Ultrasound-Diagnosed Tibia Stress Fracture: A Case Report.

PubMed

Amoako, Adae; Abid, Ayesha; Shadiack, Anthony; Monaco, Robert

2017-01-01

Stress fractures are a frequent cause of lower extremity pain in athletes, and especially in runners. Plain imaging has a low sensitivity. Magnetic resonance imaging (MRI) or bone scan scintigraphy is the criterion standard, but expensive. We present the case of a young female distance runner with left shin pain. Plain radiography was unremarkable. Ultrasound showed focal hyperechoic elevation of the periosteum with irregularity over the distal tibia and increased flow on Doppler. These findings were consistent with a distal tibia stress fracture and confirmed by MRI. Examination of our case will highlight the utility of considering an ultrasound for diagnosis of tibial stress fracture.

Ultrasound-Diagnosed Tibia Stress Fracture: A Case Report

PubMed Central

Amoako, Adae; Abid, Ayesha; Shadiack, Anthony; Monaco, Robert

2017-01-01

Stress fractures are a frequent cause of lower extremity pain in athletes, and especially in runners. Plain imaging has a low sensitivity. Magnetic resonance imaging (MRI) or bone scan scintigraphy is the criterion standard, but expensive. We present the case of a young female distance runner with left shin pain. Plain radiography was unremarkable. Ultrasound showed focal hyperechoic elevation of the periosteum with irregularity over the distal tibia and increased flow on Doppler. These findings were consistent with a distal tibia stress fracture and confirmed by MRI. Examination of our case will highlight the utility of considering an ultrasound for diagnosis of tibial stress fracture. PMID:28469488

Transverse Stress Fracture of the Proximal Patella: A Case Report.

PubMed

Atsumi, Satoru; Arai, Yuji; Kato, Ko; Nishimura, Akinobu; Nakazora, Shigeto; Nakagawa, Shuji; Ikoma, Kazuya; Fujiwara, Hiroyoshi; Sudo, Akihiro; Kubo, Toshikazu

2016-02-01

Among stress fractures associated with sports activities, patellar stress fracture is rare. Regarding patella stress fractures, so far only distal transverse or lateral longitudinal fractures have been reported, but there are no reports of transverse fractures occurring in the proximal patella. We describe an extremely rare case of transverse stress fracture of proximal patella in a 9-year-old athlete.A 9-year old boy, who participated in sports (sprints and Kendo) presented with left knee pain without any external injury. In plain radiographs, a fracture line was observed in the proximal 1/3 of the left patella, and a patella stress fracture was diagnosed. For treatment, because 7 months of conservative therapy showed no improvement, internal fixation was carried out using Acutrak screws, and bone union was thus achieved. Three months after the operation, he was able to return to his previous level of athletic sports activity.Regarding the mechanism of onset, it is believed that the causes are longitudinal traction force and patellofemoral contact pressure. On the other hand, the contact region of the patella with the femur changes with the flexion angle of the knee. In the current case, the fracture occurred at a site where the patella was in contact with the femur at a flexion angle of >90°, so it is believed that it occurred as a clinical condition from being subjected to repeated longitudinal traction force and patellofemoral contact pressure at a flexion angle of >90°, during the sports activities of sprints and Kendo. The nonunion of the transverse stress fracture of his proximal patella was successfully treated with internal fixation using Acutrak screws.

Proximal tibial stress fracture associated with mild osteoarthritis of the knee: case report.

PubMed

Curković, Marko; Kovac, Kristina; Curković, Bozidar; Babić-Naglić, Durda; Potocki, Kristina

2011-03-01

Stress fractures are considered as multifactorial overuse injuries occurring in 0.3%-0.8% of patients suffering from rheumatic diseases, with rheumatoid arthritis being the most common underlying condition. Stress fractures can be classified according to the condition of the bone affected as: 1) fatigue stress fractures occurring when normal bone is exposed to repeated abnormal stresses; and 2) insufficiency stress fractures that occur when normal stress is applied to bone weakened by an underlying condition. Stress fractures are rarely associated with severe forms of knee osteoarthritis, accompanied with malalignment and obesity. We present a patient with a proximal tibial stress fracture associated with mild knee osteoarthritis without associated malalignment or obesity. Stress fracture should be considered when a patient with osteoarthritis presents with sudden deterioration, severe localized tenderness to palpation and localized swelling or periosteal thickening at the pain site and elevated local temperature. The diagnosis of stress fractures in patients with rheumatic diseases may often be delayed because plain film radiographs may not reveal a stress fracture soon after the symptom onset; moreover, evidence of a fracture may never appear on plain radiographs. Triple phase nuclear bone scans and magnetic resonance imaging are more sensitive in the early clinical course than plain films for initial diagnosis.

Stress fractures about the tibia, foot, and ankle.

PubMed

Shindle, Michael K; Endo, Yoshimi; Warren, Russell F; Lane, Joseph M; Helfet, David L; Schwartz, Elliott N; Ellis, Scott J

2012-03-01

In competitive athletes, stress fractures of the tibia, foot, and ankle are common and lead to considerable delay in return to play. Factors such as bone vascularity, training regimen, and equipment can increase the risk of stress fracture. Management is based on the fracture site. In some athletes, metabolic workup and medication are warranted. High-risk fractures, including those of the anterior tibial diaphysis, navicular, proximal fifth metatarsal, and medial malleolus, present management challenges and may require surgery, especially in high-level athletes who need to return to play quickly. Noninvasive treatment modalities such as pulsed ultrasound and extracorporeal shock wave therapy may have some benefit but require additional research.

The role of local stress perturbation on the simultaneous opening of orthogonal fractures

NASA Astrophysics Data System (ADS)

Boersma, Quinten; Hardebol, Nico; Barnhoorn, Auke; Bertotti, Giovanni; Drury, Martyn

2016-04-01

Orthogonal fracture networks (ladder-like networks) are arrangements that are commonly observed in outcrop studies. They form a particularly dense and well connected network which can play an important role in the effective permeability of tight hydrocarbon or geothermal reservoirs. One issue is the extent to which both the long systematic and smaller cross fractures can be simultaneously critically stressed under a given stress condition. Fractures in an orthogonal network form by opening mode-I displacements in which the main component is separation of the two fracture walls. This opening is driven by effective tensile stresses as the smallest principle stress acting perpendicular to the fracture wall, which accords with linear elastic fracture mechanics. What has been well recognized in previous field and modelling studies is how both the systematic fractures and perpendicular cross fractures require the minimum principle stress to act perpendicular to the fracture wall. Thus, these networks either require a rotation of the regional stress field or local perturbations in stress field. Using a mechanical finite element modelling software, a geological case of layer perpendicular systematic mode I opening fractures is generated. New in our study is that we not only address tensile stresses at the boundary, but also address models using pore fluid pressure. The local stress in between systematic fractures is then assessed in order to derive the probability and orientation of micro crack propagation using the theory of sub critical crack growth and Griffith's theory. Under effective tensile conditions, the results indicate that in between critically spaced systematic fractures, local effective tensile stresses flip. Therefore the orientation of the least principle stress will rotate 90°, hence an orthogonal fracture is more likely to form. Our new findings for models with pore fluid pressures instead of boundary tension show that the magnitude of effective tension

Dynamic Response in Transient Stress-Field Behavior Induced by Hydraulic Fracturing

NASA Astrophysics Data System (ADS)

Jenkins, Andrew

Hydraulic fracturing is a technique which is used to exploit geologic features and subsurface properties in an effort to increase production in low-permeability formations. The process of hydraulic fracturing provides a greater surface contact area between the producing formation and the wellbore and thus increases the amount of recoverable hydrocarbons from within the reservoir. The use of this stimulation technique has brought on massive applause from the industry due to its widespread success and effectiveness, however the dynamic processes that take part in the development of hydraulic fractures is a relatively new area of research with respect to the massive scale operations that are seen today. The process of hydraulic fracturing relies upon understanding and exploiting the in-situ stress distribution throughout the area of study. These in-situ stress conditions are responsible for directing fracture orientation and propagation paths throughout the period of injection. The relative magnitude of these principle stresses is key in developing a successful stimulation plan. In horizontal well plan development the interpretation of stress within the reservoir is required for determining the azimuth of the horizontal well path. These horizontal laterals are typically oriented in a manner such that the well path lies parallel to the minimum horizontal stress. This allows for vertical fractures to develop transversely to the wellbore, or normal to the least principle stress without the theoretical possibility of fractures overlapping, creating the most efficient use of the fluid energy during injection. The orientation and magnitude of these in-situ stress fields however can be dynamic, controlled by the subsequent fracture propagation and redistribution of the surrounding stresses. That is, that as the fracture propagates throughout the reservoir, the relative stress fields surrounding the fractures may see a shift and deviate from their original direction or

Update on stress fractures in female athletes: epidemiology, treatment, and prevention.

PubMed

Chen, Yin-Ting; Tenforde, Adam S; Fredericson, Michael

2013-06-01

Stress fractures are a common type of overuse injury in athletes. Females have unique risk factors such as the female athlete triad that contribute to stress fracture injuries. We review the current literature on risk factors for stress fractures, including the role of sports participation and nutrition factors. Discussion of the management of stress fractures is focused on radiographic criteria and anatomic location and how these contribute to return to play guidelines. We outline the current recommendations for evaluating and treatment of female athlete triad. Technologies that may aid in recovery from a stress fracture including use of anti-gravity treadmills are discussed. Prevention strategies may include early screening of female athlete triad, promoting early participation in activities that improve bone health, nutritional strategies, gait modification, and orthotics.

Stress Fractures of the Foot.

PubMed

Hossain, Munier; Clutton, Juliet; Ridgewell, Mark; Lyons, Kathleen; Perera, Anthony

2015-10-01

Stress fractures of the foot and ankle may be more common among athletes than previously reported. A low threshold for investigation is warranted and further imaging may be appropriate if initial radiographs remain inconclusive. Most of these fractures can be treated conservatively with a period of non-weight-bearing mobilization followed by gradual return to activity. Early surgery augmented by bone graft may allow athletes to return to sports earlier. Risk of delayed union, nonunion, and recurrent fracture is high. Many of the patients may also have risk factors for injury that should be modified for a successful outcome. Copyright © 2015 Elsevier Inc. All rights reserved.

Taking a holistic approach to managing difficult stress fractures.

PubMed

Miller, Timothy L; Best, Thomas M

2016-09-09

Stress fractures and other bony stress injuries occur along a spectrum of severity which can impact treatment and prognosis. When treating these injuries, it should be borne in mind that no two stress fractures behave exactly alike. Given that they are not a consistent injury, standardized treatment protocols can be challenging to develop. Treatment should be individualized to the patient or athlete, the causative activity, the anatomical site, and the severity of the injury. A holistic approach to the treatment of the most difficult stress fractures should be taken by orthopedists and sports medicine specialists. This approach is necessary to obtain optimal outcomes, minimize loss of fitness and time away from sports participation, and decrease the risk of recurrence.

Stress analysis of implant-bone fixation at different fracture angle

NASA Astrophysics Data System (ADS)

Izzawati, B.; Daud, R.; Afendi, M.; Majid, MS Abdul; Zain, N. A. M.; Bajuri, Y.

2017-10-01

Internal fixation is a mechanism purposed to maintain and protect the reduction of a fracture. Understanding of the fixation stability is necessary to determine parameters influence the mechanical stability and the risk of implant failure. A static structural analysis on a bone fracture fixation was developed to simulate and analyse the biomechanics of a diaphysis shaft fracture with a compression plate and conventional screws. This study aims to determine a critical area of the implant to be fractured based on different implant material and angle of fracture (i.e. 0°, 30° and 45°). Several factors were shown to influence stability to implant after surgical. The stainless steel, (S. S) and Titanium, (Ti) screws experienced the highest stress at 30° fracture angle. The fracture angle had a most significant effect on the conventional screw as compared to the compression plate. The stress was significantly higher in S.S material as compared to Ti material, with concentrated on the 4th screw for all range of fracture angle. It was also noted that the screws closest to the intense concentration stress areas on the compression plate experienced increasing amounts of stress. The highest was observed at the screw thread-head junction.

Sacral neuromodulation and cardiac pacemakers.

PubMed

Roth, Ted M

2010-08-01

Potential for cross-talk between cardiac pacemakers and sacral neuromodulation remains speculative. We present a case series of patients with cardiac pacemakers who underwent staged Interstim (Medtronic, Minneapolis, MN) implantation and patients who had pulse generator implantation who later required cardiac pacemakers. No cross-talk was demonstrated in either group. Sacral neuromodulation appears to be safe in the setting of cardiac pacemakers without cardioversion/defibrillation technology.

RANK/RANKL/OPG pathway: genetic associations with stress fracture period prevalence in elite athletes.

PubMed

Varley, Ian; Hughes, David C; Greeves, Julie P; Stellingwerff, Trent; Ranson, Craig; Fraser, William D; Sale, Craig

2015-02-01

The RANK/RANKL/OPG signalling pathway is important in the regulation of bone turnover, with single nucleotide polymorphisms (SNPs) in genes within this pathway associated with bone phenotypic adaptations. To determine whether four SNPs associated with genes in the RANK/RANKL/OPG signalling pathway were associated with stress fracture injury in elite athletes. Radiologically confirmed stress fracture history was reported in 518 elite athletes, forming the Stress Fracture Elite Athlete (SFEA) cohort. Data were analysed for the whole group and were sub-stratified into male and cases of multiple stress fracture groups. Genotypes were determined using proprietary fluorescence-based competitive allele-specific PCR assays. SNPs rs3018362 (RANK) and rs1021188 (RANKL) were associated with stress fracture injury (P<0.05). 8.1% of the stress fracture group and 2.8% of the non-stress fracture group were homozygote for the rare allele of rs1021188. Allele frequency, heterozygotes and homozygotes for the rare allele of rs3018362 were associated with stress fracture period prevalence (P<0.05). Analysis of the male only group showed 8.2% of rs1021188 rare allele homozygotes had suffered a stress fracture whilst 2.5% of the non-stress fracture group were homozygous. In cases of multiple stress fractures, homozygotes for the rare allele of rs1021188 and individuals possessing at least one copy of the rare allele of rs4355801 (OPG) were shown to be associated with stress fracture injury (P<0.05). The data support an association between SNPs in the RANK/RANKL/OPG signalling pathway and the development of stress fracture injury. The association of rs3018362 (RANK) and rs1021188 (RANKL) with stress fracture injury susceptibility supports their role in the maintenance of bone health and offers potential targets for therapeutic interventions. Copyright © 2014 Elsevier Inc. All rights reserved.

Stress Fractures of Tibia Treated with Ilizarov External Fixator.

PubMed

Górski, Radosław; Żarek, Sławomir; Modzelewski, Piotr; Górski, Ryszard; Małdyk, Paweł

2016-08-30

Stress fractures are the result of cyclic loading of the bone, which gradually becomes damaged. Most often they are treated by rest or plaster cast and, in rare cases, by internal fixation. There is little published data on initial reposition followed by stabilization with the Ilizarov apparatus in such fractures. Six patients were treated with an external fixator according to the Ilizarov method for a stress fracture of the tibia between 2007 and 2015. Three patients were initially treated conservatively. Due to increasing tibial deformation, they were qualified for surgical treatment with external stabilization. In the other patients, surgery was the first-line treatment. All patients demonstrated risk factors for a stress fracture. After the surgery, they fully loaded the operated limb. No patient developed malunion, nonunion, infection or venous thrombosis. The average time from the first operation to the removal of the external fixator was 19 weeks. Radiographic and clinical outcomes were satisfactory in all patients. 1. The Ilizarov method allows for successful stabilization of stress fractures of the tibia. 2. It may be a good alternative to internal stabilization, especially in patients with multiple comorbidities which affect bone quality and may impair soft tissue healing.

Risk factors for stress fracture among young female cross-country runners.

PubMed

Kelsey, Jennifer L; Bachrach, Laura K; Procter-Gray, Elizabeth; Nieves, Jeri; Greendale, Gail A; Sowers, Maryfran; Brown, Byron W; Matheson, Kim A; Crawford, Sybil L; Cobb, Kristin L

2007-09-01

To identify risk factors for stress fracture among young female distance runners. Participants were 127 competitive female distance runners, aged 18-26, who provided at least some follow-up data in a randomized trial among 150 runners of the effects of oral contraceptives on bone health. After completing a baseline questionnaire and undergoing bone densitometry, they were followed an average of 1.85 yr. Eighteen participants had at least one stress fracture during follow-up. Baseline characteristics associated (P<0.10) in multivariate analysis with stress fracture occurrence were one or more previous stress fractures (rate ratio [RR] [95% confidence interval]=6.42 (1.80-22.87), lower whole-body bone mineral content (RR=2.70 [1.26-5.88] per 1-SD [293.2 g] decrease), younger chronologic age (RR=1.42 [1.05-1.92] per 1-yr decrease), lower dietary calcium intake (RR=1.11 [0.98-1.25] per 100-mg decrease), and younger age at menarche (RR=1.92 [1.15-3.23] per 1-yr decrease). Although not statistically significant, a history of irregular menstrual periods was also associated with increased risk (RR=3.41 [0.69-16.91]). Training-related factors did not affect risk. The results of this and other studies indicate that risk factors for stress fracture among young female runners include previous stress fractures, lower bone mass, and, although not statistically significant in this study, menstrual irregularity. More study is needed of the associations between stress fracture and age, calcium intake, and age at menarche. Given the importance of stress fractures to runners, identifying preventive measures is of high priority.

Thermal stress fracture of ceramic coatings

NASA Technical Reports Server (NTRS)

Andersson, C. A.

1983-01-01

Thermal stress failures of ceramic coatings are discussed in terms of fracture mechanics concepts. The effects of transient and residual stresses on single and multiple cycle failure mechanisms are considered. A specific example of a zirconia thermal barrier coating is presented and its endurance calculated using the proposed relationships.

Interpretation and classification of bone scintigraphic findings in stress fractures.

PubMed

Zwas, S T; Elkanovitch, R; Frank, G

1987-04-01

A new system for classification of stress fractures identified by bone scintigraphy was developed and divided into four grades according to lesion dimension, bone extension, and tracer accumulation. The scintigraphic findings were evaluated for severity of lesions by extent of the visualized bone response, ranging from ill-defined cortical lesions with slightly increased activity (I) to well-defined intramedullary transcortical lesions with intensely increased activity (IV). Bone scintigraphies using [99mTc]MDP were obtained in 310 military recruits suspected of having stress fractures. In 235 patients, 391 stress fractures were diagnosed. Forty percent of the lesions were asymptomatic. Most of the lesions were in the tibiae (72%), and 87% of the patients had one or two lesions, while 13% had three to five lesions. Eighty-five percent of the lesions were classified as mild and showed early and more complete resolution on follow-up studies after treatment as compared to the severe grades. Furthermore, specific scintigraphic patterns have been introduced for distinguishing inflammatory shin-splints from stress fractures, allowing for their appropriate early treatment. Thus, early recognition of mild stress fracture scintigraphic patterns representing the beginning of pathologic bone response to stress enabled a prompt and effective treatment to prevent progression of lesions, protracted disability, and complications.

Diagnosis, treatment, and rehabilitation of stress fractures in the lower extremity in runners

PubMed Central

Kahanov, Leamor; Eberman, Lindsey E; Games, Kenneth E; Wasik, Mitch

2015-01-01

Stress fractures account for between 1% and 20% of athletic injuries, with 80% of stress fractures in the lower extremity. Stress fractures of the lower extremity are common injuries among individuals who participate in endurance, high load-bearing activities such as running, military and aerobic exercise and therefore require practitioner expertise in diagnosis and management. Accurate diagnosis for stress fractures is dependent on the anatomical area. Anatomical regions such as the pelvis, sacrum, and metatarsals offer challenges due to difficulty differentiating pathologies with common symptoms. Special tests and treatment regimes, however, are similar among most stress fractures with resolution between 4 weeks to a year. The most difficult aspect of stress fracture treatment entails mitigating internal and external risk factors. Practitioners should address ongoing risk factors to minimize recurrence. PMID:25848327

A Discrete Fracture Network Model with Stress-Driven Nucleation and Growth

NASA Astrophysics Data System (ADS)

Lavoine, E.; Darcel, C.; Munier, R.; Davy, P.

2017-12-01

The realism of Discrete Fracture Network (DFN) models, beyond the bulk statistical properties, relies on the spatial organization of fractures, which is not issued by purely stochastic DFN models. The realism can be improved by injecting prior information in DFN from a better knowledge of the geological fracturing processes. We first develop a model using simple kinematic rules for mimicking the growth of fractures from nucleation to arrest, in order to evaluate the consequences of the DFN structure on the network connectivity and flow properties. The model generates fracture networks with power-law scaling distributions and a percentage of T-intersections that are consistent with field observations. Nevertheless, a larger complexity relying on the spatial variability of natural fractures positions cannot be explained by the random nucleation process. We propose to introduce a stress-driven nucleation in the timewise process of this kinematic model to study the correlations between nucleation, growth and existing fracture patterns. The method uses the stress field generated by existing fractures and remote stress as an input for a Monte-Carlo sampling of nuclei centers at each time step. Networks so generated are found to have correlations over a large range of scales, with a correlation dimension that varies with time and with the function that relates the nucleation probability to stress. A sensibility analysis of input parameters has been performed in 3D to quantify the influence of fractures and remote stress field orientations.

Patterns of Fracture and Tidal Stresses Due to Nonsynchronous Rotation: Implications for Fracturing on Europa

NASA Technical Reports Server (NTRS)

Parmentier, E. M.; Helfenstein, P.

1985-01-01

Global lineaments on Europa were interpreted as fractures in an icy crust. A variety of lineament types were identified, which appear to form a systematic pattern on the surface. For a synchronously rotating body, the patterns of fractures observed could be produced by a combination of stresses due to orbital recession, orbital eccentricity, and internal contraction. However, it was recently suggested that the forced eccentricity of Europa's orbit may result in nonsynchronous rotation. The hypothesis that fractures in a thin icy crust may have formed in response to stresses resulting from nonsynchronous rotation is studied.

Patterns of fracture and tidal stresses due to nonsynchronous rotation - Implications for fracturing on Europa

NASA Technical Reports Server (NTRS)

Helfenstein, P.; Parmentier, E. M.

1985-01-01

This study considers the global patterns of fracture that would result from nonsynchronous rotation of a tidally distorted planetary body. The incremental horizontal stresses in a thin elastic or viscous shell due to a small displacement of the axis of maximum tidal elongation are derived, and the resulting stress distributions are applied to interpret the observed pattern of fracture lineaments on Europa. The observed pattern of lineaments can be explained by nonsynchronous rotation if these features formed by tension fracturing and dike emplacement. Tension fracturing can occur for a small displacement of the tidal axis, so that the resulting lineaments may be consistent with other evidence suggesting a young age for the surface.

The Contribution of SPECT/CT in the Diagnosis of Stress Fracture of the Proximal Tibia.

PubMed

Okudan, Berna; Coşkun, Nazım; Arıcan, Pelin

2018-02-01

Stress fractures are injuries most commonly seen in the lower limbs and are usually caused by repetitive stress. While the distal and middle third of the tibia is the most frequent site for stress fractures (almost 50%), stress fractures of the proximal tibia is relatively rare and could be confused with other types of tibial fractures, thus altering management plans for the clinician. Early diagnosis of stress fractures is also important to avoid complications. Imaging plays an important role in the diagnosis of stress fractures, especially bone scan. Combined with single-photon emission computed tomography/computed tomography (SPECT/CT) it is an important imaging technique for stress fractures in both upper and lower extremities, and is widely preferred over other imaging techniques. In this case, we present the case of a 39-year-old male patient diagnosed with stress fracture of the proximal tibia and demonstrate the contribution of CT scan fused with SPECT imaging in the early diagnosis of stress fracture prior to other imaging modalities.

Malignant fibrous histiocytoma developing in irradiated sacral chordoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Halpern, J.; Kopolovic, J.; Catane, R.

1984-06-15

Malignant fibrous histiocytoma (MFH), arising at the site of a sacral chordoma 8 years after massive radiotherapy, is described. Initially, the patient received 7000 rad to the sacral area and, on recurrence, 5 years later, an additional 4000 rad. Two years later, a sacral mass was noted again. Biopsy then revealed MFH; chest x-ray showed multiple lung metastases. A combination chemotherapy, consisting of cyclophosphamide, vincristine, adriamycin (doxorubicin), and DTIC, resulted in a 6 month partial response. Subsequently, the patient died because of progressive metastatic disease. At autopsy, 8 years after diagnosis, both the sacral lesion and the lung metastases provedmore » to be MFH, and no residual chordoma was found.« less

Expected Time to Return to Athletic Participation After Stress Fracture in Division I Collegiate Athletes.

PubMed

Miller, Timothy L; Jamieson, Marissa; Everson, Sonsecharae; Siegel, Courtney

2017-12-01

Few studies have documented expected time to return to athletic participation after stress fractures in elite athletes. Time to return to athletic participation after stress fractures would vary by site and severity of stress fracture. Retrospective cohort study. Level 3. All stress fractures diagnosed in a single Division I collegiate men's and women's track and field/cross-country team were recorded over a 3-year period. Site and severity of injury were graded based on Kaeding-Miller classification system for stress fractures. Time to return to full unrestricted athletic participation was recorded for each athlete and correlated with patient sex and site and severity grade of injury. Fifty-seven stress fractures were diagnosed in 38 athletes (mean age, 20.48 years; range, 18-23 years). Ten athletes sustained recurrent or multiple stress fractures. Thirty-seven injuries occurred in women and 20 in men. Thirty-three stress fractures occurred in the tibia, 10 occurred in the second through fourth metatarsals, 3 occurred in the fifth metatarsal, 6 in the tarsal bones (2 navicular), 2 in the femur, and 5 in the pelvis. There were 31 grade II stress fractures, 11 grade III stress fractures, and 2 grade V stress fractures (in the same patient). Mean time to return to unrestricted sport participation was 12.9 ± 5.2 weeks (range, 6-27 weeks). No significant differences in time to return were noted based on injury location or whether stress fracture was grade II or III. The expected time to return to full unrestricted athletic participation after diagnosis of a stress fracture is 12 to 13 weeks for all injury sites. Athletes with grade V (nonunion) stress fractures may require more time to return to sport.

The effect of stress fracture interventions in a single elite infantry training unit (1983-2015).

PubMed

Milgrom, Charles; Finestone, Aharon S

2017-10-01

Stress fractures can be seen as an undesired byproduct of demanding physical training. The threshold value of stress that places an individual bone at high risk for stress fracture has not been identified. In a prospective study of stress fractures in 1983, a 31% incidence was found during demanding Israeli infantry basic training by bone scan criteria. Within a subgroup of these recruits, an elite infantry unit was found to have a 40% incidence. Since then and until 2015, eight additional induction companies of the same elite infantry unit were prospectively monitored for stress fractures during their basic training. In all of the studies, stress fracture surveillance and the examining orthopedist were the same. A retrospective review of all nine studies and of eight training changes was performed to look for a temporal trend in stress fracture incidence and to see if these might be related to training changes. There was a statistically significant trend for lower radiological proven stress fractures (p=0.0001) and radiological proven stress fractures plus clinical stress fractures (p=0.0013), as well as lower stress fracture severity by radiological criteria (p=0.0001) between 1983 and 2015. The only training change that was associated, by multivariate logistic regression, with a decreased incidence of stress fracture was restricting training to the authorized training protocol (odds ratio, 3874; 95% CI, 1.526 to 9.931; p=0.004). Increased recruit weight was found by multivariate analysis to be associated with lower stress fracture incidence (odds ratio 1.034; 95% CI, 1.00 to 1.070; p=0.051). Moving the training to a base with flatter terrain and reducing the formal marching distance by 1/3 was associated with a decrease in high grade stress fractures (odds ratio, 10.03; 95% CI, 3.5 to 28.4; p=0.0001). Neither the combined changes of enforcing a seven hour a night sleep regimen, training in more comfortable boots and adding a physical therapist to the unit nor

Multiple stress fractures in a young female runner.

PubMed

Dusek, T; Pećina, M; Loncar-Dusek, M; Bojanic, I

2004-01-01

The effect of exercise on female's bone metabolism has received much attention in recent years. We report on unusual case of a female runner with low body mass and amenorrhea, who suffered 4 stress fractures. Three of the stress fractures occurred during her sports career, and the fourth occurred 7 years after the cessation of sports activities. It seems that exercise-induced amenorrhea together with food restriction in the young age may cause long-term consequences on bone metabolism.

[Sacral nerve stimulation in fecal incontinence].

PubMed

Rasmussen, Ole Ø; Christiansen, John

2002-08-12

Sacral nerve stimulation for the treatment of faecal incontinence has gained increasing use in Europe over the last two years. Experience with the first patients treated in Denmark is described here. Fourteen patients with severe faecal incontinence were given sacral nerve stimulation. The first treatment was temporary, and if this was successful they had a device for permanent stimulation implanted. The result of the test stimulation was good in ten of the 14 patients and a permanent system was implanted. After a median of 4.5 months' stimulation, nine of the ten patients continued to respond to respond well. Sacral nerve stimulation in the treatment of faecal incontinence shows promising results. Compared to other more advanced forms of treatment, this method is minimally invasive.

Spallation and fracture resulting from reflected and intersecting stress waves.

NASA Technical Reports Server (NTRS)

Kinslow, R.

1973-01-01

Discussion of the effects of stress waves produced in solid by explosions or high-velocity impacts. These waves rebound from free surfaces in the form of tensile waves that are capable of causing internal fractures or spallation of the material. The high-speed framing camera is shown to be an important tool for observing the stress waves and fracture in transparent targets, and its photographs provide valuable information on the mechanics of fracture.

Tibial stress fracture after computer-navigated total knee arthroplasty.

PubMed

Massai, F; Conteduca, F; Vadalà, A; Iorio, R; Basiglini, L; Ferretti, A

2010-06-01

A correct alignment of the tibial and femoral component is one of the most important factors determining favourable long-term results of a total knee arthroplasty (TKA). The accuracy provided by the use of the computer navigation systems has been widely described in the literature so that their use has become increasingly popular in recent years; however, unpredictable complications, such as displaced or stress femoral or tibial fractures, have been reported to occur a few weeks after the operation. We present a case of a stress tibial fracture that occurred after a TKA performed with the use of a computer navigation system. The stress fracture, which eventually healed without further complications, occurred at one of the pinhole sites used for the placement of the tibial trackers.

Screw Loosening and Pelvic Canal Narrowing After Lateral Plating of Feline Ilial Fractures With Locking and Nonlocking Plates.

PubMed

Schmierer, Philipp A; Kircher, Patrick R; Hartnack, Sonja; Knell, Sebastian C

2015-10-01

To compare the frequency of complications, including screw loosening and pelvic canal narrowing, associated with dynamic compression plating, locking plating, and double locking plating of ilial fractures in cats. Historical cohort study. The radiographs and medical records of cats with pelvic fractures that were presented between 2004 and 2013 were reviewed. The cases were categorized based on the plate type and number as dynamic compression plate (DCP), single locking plate (LPS) and double locking plates (dLPS). The frequency of screw loosening was compared across categories using a Fisher's exact test. The change in pelvic alignment, described by the change in sacral index (postoperative sacral index-followup sacral index), was compared across plate categories using ANOVA. The frequency of screw loosening for DCP (5/10) was significantly higher than LPS (1/13) and dLPS (0/11) (P = .05, P = .012, respectively). There was no significant difference in the SI change across plate categories. The mean change in sacral index for DCP was -0.11 (95%CI -0.25 to 0.03), for LPS was 0.0007 (95%CI -0.07 to 0.08), and for dLPS was -0.01 (95%CI -0.04 to 0.02). None of the cats showed constipation postoperatively. Screw loosening occurred less often but the change in pelvic canal alignment was not significantly different in ilial fractures repaired with LPS or dLPS compared to ilial fractures repaired with DCP. Locking plating of ilial fractures in cats may offer advantages compared to nonlocking plating. © Copyright 2015 by The American College of Veterinary Surgeons.

Step test performance and risk of stress fractures among female army trainees.

PubMed

Cowan, David N; Bedno, Sheryl A; Urban, Nadia; Lee, Dara S; Niebuhr, David W

2012-06-01

Stress fractures and other musculoskeletal injuries are major sources of morbidity among female military trainees. Several risk factors have been postulated, particularly pre-existing fitness, usually assessed with post-entry run time for ≥ 1.0 mile. Physical fitness is not formally evaluated prior to Army entry. If a valid and simple test that identified women at increased risk of stress fracture were available and could be applied prior to entry, it would facilitate cost-benefit studies of deferral or interventions. These analyses were undertaken to determine if a 5-minute step test conducted before entry identified women at increased risk. A prospective study was conducted of weight-qualified women entering the Army in 2005-2006, with analyses completed in 2011. At the pre-entry examination, information was collected on age, BMI, smoking, race, and activity level. Everyone took the step test. All outpatient medical encounters were captured, and stress fractures and other musculoskeletal injuries identified. Women with stress fractures and those with other musculoskeletal injuries were evaluated separately. 1568 women were included in the study; 109 developed stress fractures and 803 other musculoskeletal injury. Women who failed the step test had a 76% higher stress fracture incidence and a 35% higher incidence of other musculoskeletal injuries. There was effect modification between age and test failure for stress fracture. A step test that can be administered before military entry identifies women with increased incidence of stress fracture and other musculoskeletal injury. This test could be used pre-entry to defer or target high-risk recruits for tailored fitness training before or after military entrance. Copyright © 2012 American Journal of Preventive Medicine. All rights reserved.

Stress fracture risk factors in female football players and their clinical implications

PubMed Central

Warden, Stuart J; Creaby, Mark W; Bryant, Adam L; Crossley, Kay M

2007-01-01

A stress fracture represents the inability of the skeleton to withstand repetitive bouts of mechanical loading, which results in structural fatigue, and resultant signs and symptoms of localised pain and tenderness. Reports of stress fractures in female football players are not prevalent; however, they are probably under‐reported and their importance lies in the morbidity that they cause in terms of time lost from participation. By considering risk factors for stress fractures in female football players it may be possible to reduce the impact of these troublesome injuries. Risk factors for stress fractures in female football players include intrinsic risk factors such as gender, endocrine, nutritional, physical fitness and neuromusculoskeletal factors, as well as extrinsic risk factors such as training programme, equipment and environmental factors. This paper discusses these risk factors and their implications in terms of developing prevention and management strategies for stress fractures in female football players. PMID:17584950

Stress fracture risk factors in female football players and their clinical implications.

PubMed

Warden, Stuart J; Creaby, Mark W; Bryant, Adam L; Crossley, Kay M

2007-08-01

A stress fracture represents the inability of the skeleton to withstand repetitive bouts of mechanical loading, which results in structural fatigue, and resultant signs and symptoms of localised pain and tenderness. Reports of stress fractures in female football players are not prevalent; however, they are probably under-reported and their importance lies in the morbidity that they cause in terms of time lost from participation. By considering risk factors for stress fractures in female football players it may be possible to reduce the impact of these troublesome injuries. Risk factors for stress fractures in female football players include intrinsic risk factors such as gender, endocrine, nutritional, physical fitness and neuromusculoskeletal factors, as well as extrinsic risk factors such as training programme, equipment and environmental factors. This paper discusses these risk factors and their implications in terms of developing prevention and management strategies for stress fractures in female football players.

First-rib stress fracture in two adolescent swimmers: a case report.

PubMed

Low, Sara; Kern, Michael; Atanda, Alfred

2016-01-01

First-rib stress fractures have been described in adolescent athletes in various sports, with only one prior case report of first-rib stress fractures in an adolescent female swimmer. There is a need for research on the cause, management, and prevention of these injuries as they lead to significant morbidity and critical time away from sport for these aspiring athletes. We aimed to describe first-rib stress fractures as a potential cause for non-specific atraumatic chronic shoulder pain in adolescent swimmers and to discuss the different presentations, unique risk factors, treatment, and potential injury prevention strategies of such fractures. We discussed two such cases which were successfully treated with activity modification with restriction of all overhead activity, gradually progressive physical therapy and a return to swimming protocol. First-rib stress fractures can vary in presentation and should be in the differential diagnosis in adolescent swimmers with chronic shoulder pain. These injuries can be successfully managed with rest from overhead activities and physical therapy. Gradual return to competitive swimming can be achieved even with non-union of a first-rib stress fracture. Emphasis on balanced strength training in different muscle groups and proper swimming technique is essential to prevent these injuries.

Stress Analysis and Fracture in Nanolaminate Composites

NASA Technical Reports Server (NTRS)

Chamis, Christos C.

2008-01-01

A stress analysis is performed on a nanolaminate subjected to bending. A composite mechanics computer code that is based on constituent properties and nanoelement formulation is used to evaluate the nanolaminate stresses. The results indicate that the computer code is sufficient for the analysis. The results also show that when a stress concentration is present, the nanolaminate stresses exceed their corresponding matrix-dominated strengths and the nanofiber fracture strength.

Bilateral femoral neck stress fractures in military recruits with unilateral hip pain.

PubMed

Moo, Ing How; Lee, Y H D; Lim, K K; Mehta, K V

2016-10-01

Femoral neck stress fractures are rare and can be easily missed and failure to diagnose these injuries early can lead to avascular necrosis, malunion and osteoarthritis. It is important to have a high index of suspicion for femoral neck stress fractures in military recruits. We present three cases of bilateral femoral neck fractures in military recruits, all presenting with unilateral hip symptoms and signs. All the asymptomatic contralateral hips had femoral neck stress fractures diagnosed by screening MRI. Tension type and displaced femoral neck fractures were treated surgically. All the fractures managed healing without complications. Military recruits with unilateral groin pain should have an early referral for MRI hip to rule out femoral neck stress fractures and those military personnel with ipsilateral femoral neck fracture should have MRI of the contralateral hip. Two of the patients had vitamin D deficiency, of which one had elevated parathyroid hormones and low bone mineral density. Our case series highlights the significance of vitamin D deficiency among military recruits. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Acoustic Emission Based Surveillance System for Prediction of Stress Fractures

DTIC Science & Technology

2007-09-01

aging are susceptible to such fractures in contexts of osteoporosis, diabetes, cerebral palsy, fibrous dysplasia and osteogenesis imperfecta . This...disease, or, healthy people who have excessive exercise regimes (soldiers and athletes) experience these fractures [2]. Stress fractures interrupt

Medial tibial plateau morphology and stress fracture location: A magnetic resonance imaging study.

PubMed

Yukata, Kiminori; Yamanaka, Issei; Ueda, Yuzuru; Nakai, Sho; Ogasa, Hiroyoshi; Oishi, Yosuke; Hamawaki, Jun-Ichi

2017-06-18

To determine the location of medial tibial plateau stress fractures and its relationship with tibial plateau morphology using magnetic resonance imaging (MRI). A retrospective review of patients with a diagnosis of stress fracture of the medial tibial plateau was performed for a 5-year period. Fourteen patients [three female and 11 male, with an average age of 36.4 years (range, 15-50 years)], who underwent knee MRI, were included. The appearance of the tibial plateau stress fracture and the geometry of the tibial plateau were reviewed and measured on MRI. Thirteen of 14 stress fractures were linear, and one of them stellated on MRI images. The location of fractures was classified into three types. Three fractures were located anteromedially (AM type), six posteromedially (PM type), and five posteriorly (P type) at the medial tibial plateau. In addition, tibial posterior slope at the medial tibial plateau tended to be larger when the fracture was located more posteriorly on MRI. We found that MRI showed three different localizations of medial tibial plateau stress fractures, which were associated with tibial posterior slope at the medial tibial plateau.

Medial tibial plateau morphology and stress fracture location: A magnetic resonance imaging study

PubMed Central

Yukata, Kiminori; Yamanaka, Issei; Ueda, Yuzuru; Nakai, Sho; Ogasa, Hiroyoshi; Oishi, Yosuke; Hamawaki, Jun-ichi

2017-01-01

AIM To determine the location of medial tibial plateau stress fractures and its relationship with tibial plateau morphology using magnetic resonance imaging (MRI). METHODS A retrospective review of patients with a diagnosis of stress fracture of the medial tibial plateau was performed for a 5-year period. Fourteen patients [three female and 11 male, with an average age of 36.4 years (range, 15-50 years)], who underwent knee MRI, were included. The appearance of the tibial plateau stress fracture and the geometry of the tibial plateau were reviewed and measured on MRI. RESULTS Thirteen of 14 stress fractures were linear, and one of them stellated on MRI images. The location of fractures was classified into three types. Three fractures were located anteromedially (AM type), six posteromedially (PM type), and five posteriorly (P type) at the medial tibial plateau. In addition, tibial posterior slope at the medial tibial plateau tended to be larger when the fracture was located more posteriorly on MRI. CONCLUSION We found that MRI showed three different localizations of medial tibial plateau stress fractures, which were associated with tibial posterior slope at the medial tibial plateau. PMID:28660141

Neurovascular risks of sacral screws with bicortical purchase: an anatomical study.

PubMed

Ergur, Ipek; Akcali, Omer; Kiray, Amac; Kosay, Can; Tayefi, Hamid

2007-09-01

The aim of this cadaver study is to define the anatomic structures on anterior sacrum, which are under the risk of injury during bicortical screw application to the S1 and S2 pedicles. Thirty formaldehyde-preserved human male cadavers were studied. Posterior midline incision was performed, and soft tissues and muscles were dissected from the posterior part of the lumbosacral region. A 6 mm pedicle screw was inserted between the superior facet of S1 and the S1 foramen. The entry point of the S2 pedicle screw was located between S1 and S2 foramina. S1 and S2 screws were placed on both right and the left sides of all cadavers. Then, all cadavers were turned into supine position. All abdominal and pelvic organs were moved away and carefully observed for any injury. The tips of the sacral screws were marked and the relations with the anatomic structures were defined. The position of the sacral screws relative to the middle and lateral sacral arteries and veins, and the sacral sympathetic trunk were measured. There was no injury to the visceral organs. In four cases, S1 screw tip was in direct contact with middle sacral artery. In two cases, S1 screw tip was in direct contact with middle sacral vein. It was observed that the S1 screw tips were in close proximity to sacral sympathetic trunk on both right and the left sides. The tip of the S2 screw was in contact with middle sacral artery on the left side only in one case. It is found that the tip of the S2 screw was closely located with the middle sacral vein in two cases. The tip of the S2 pedicle screw was in contact with the sacral sympathetic trunk in eight cases on the right side and seven cases on the left side. Lateral sacral vein was also observed to be disturbed by the S1 and S2 screws. As a conclusion, anterior cortical penetration during sacral screw insertion carries a risk of neurovascular injury. The risk of sacral sympathetic trunk and minor vascular structures together with the major neurovascular

Probability of stress-corrosion fracture under random loading.

NASA Technical Reports Server (NTRS)

Yang, J.-N.

1972-01-01

A method is developed for predicting the probability of stress-corrosion fracture of structures under random loadings. The formulation is based on the cumulative damage hypothesis and the experimentally determined stress-corrosion characteristics. Under both stationary and nonstationary random loadings, the mean value and the variance of the cumulative damage are obtained. The probability of stress-corrosion fracture is then evaluated using the principle of maximum entropy. It is shown that, under stationary random loadings, the standard deviation of the cumulative damage increases in proportion to the square root of time, while the coefficient of variation (dispersion) decreases in inversed proportion to the square root of time. Numerical examples are worked out to illustrate the general results.

Regional flow simulation in fractured aquifers using stress-dependent parameters.

PubMed

Preisig, Giona; Joel Cornaton, Fabien; Perrochet, Pierre

2012-01-01

A model function relating effective stress to fracture permeability is developed from Hooke's law, implemented in the tensorial form of Darcy's law, and used to evaluate discharge rates and pressure distributions at regional scales. The model takes into account elastic and statistical fracture parameters, and is able to simulate real stress-dependent permeabilities from laboratory to field studies. This modeling approach gains in phenomenology in comparison to the classical ones because the permeability tensors may vary in both strength and principal directions according to effective stresses. Moreover this method allows evaluation of the fracture porosity changes, which are then translated into consolidation of the medium. © 2011, The Author(s). Ground Water © 2011, National Ground Water Association.

Lower extremity and pelvic stress fractures in athletes

PubMed Central

Liong, S Y; Whitehouse, R W

2012-01-01

Stress fractures occur following excessive use and are commonly seen in athletes, in whom the lower limbs are frequently involved. Delayed diagnosis and management of these injuries can result in significant long-term damage and athlete morbidity. A high index of suspicion may facilitate diagnosis, but clinical presentation may be non-specific. In this regard, imaging in the form of plain radiograph, CT, MRI and bone scintigraphy may be of value. This article reviews the incidence, presentation, radiological findings and management options for athletes with stress fractures of the lower limb. PMID:22815414

Mechanisms Underlying Stress Fracture and the Influence of Sex and Race/Ethnicity

DTIC Science & Technology

2017-10-01

penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN...history of one stress fracture (n=25), or no stress fracture history (n=25). The discrepancies in these parameters between groups will help to...women (n=40 for each group ; n=240 total). This will serve to identify factors that contribute to the differences in stress fracture incidence due to race

Parasacral Perforator Flaps for Reconstruction of Sacral Pressure Sores.

PubMed

Lin, Chin-Ta; Chen, Shih-Yi; Chen, Shyi-Gen; Tzeng, Yuan-Sheng; Chang, Shun-Cheng

2015-07-01

Despite advances in reconstruction techniques, pressure sores continue to present a challenge to the plastic surgeon. The parasacral perforator flap is a reliable flap that preserves the entire contralateral side as a future donor site. On the ipsilateral side, the gluteal muscle itself is preserved and all flaps based on the inferior gluteal artery are still possible. We present our experience of using parasacral perforator flaps in reconstructing sacral defects. Between August 2004 and January 2013, 19 patients with sacral defects were included in this study. All the patients had undergone surgical reconstruction of sacral defects with a parasacral perforator flap. The patients' sex, age, cause of sacral defect, flap size, flap type, numbers of perforators used, rotation angle, postoperative complications, and hospital stay were recorded. There were 19 parasacral perforator flaps in this series. All flaps survived uneventfully except for 1 parasacral perforator flap, which failed because of methicillin-resistant Staphylococcus aureus infection. The overall flap survival rate was 95% (18/19). The mean follow-up period was 17.3 months (range, 2-24 months). The average length of hospital stay was 20.7 days (range, 9-48 days). No flap surgery-related mortality was found. Also, there was no recurrence of sacral pressure sores or infected pilonidal cysts during the follow-up period. Perforator-based flaps have become popular in modern reconstructive surgery because of low donor-site morbidity and good preservation of muscle. Parasacral perforator flaps are durable and reliable in reconstructing sacral defects. We recommend the parasacral perforator flap as a good choice for reconstructing sacral defects.

Sacral Variability in Tailless Species: Homo sapiens and Ochotona princeps.

PubMed

Tague, Robert G

2017-05-01

Homo sapiens is variable in number of sacral vertebrae, and this variability can lead to obstetrical complication. This study uses the comparative method to test the hypothesis that sacral variability in H. sapiens is associated with absence of a tail. Three species of lagomorphs are studied: Ochotona princeps (N = 271), which is tailless, and Lepus californicus (N = 212) and Sylvilagus audubonii (N = 206), which have tails. Results show that O. princeps has (1) higher diversity index for number of sacral vertebrae (0.49) compared to L. californicus (0.25) and S. audubonii (0.26) and (2) significantly higher percentage of individuals with the species-specific nonmodal number of sacral vertebrae (43.9%) compared to L. californicus (14.2%) and S. audubonii (15.5%). Comparison of H. sapiens (N = 1,030; individuals of age 20-39 years) with O. princeps shows similarities between the species in diversity index (also 0.49 in H. sapiens) and percentage of individuals with nonmodal number of sacral vertebrae (37.3% in H. sapiens). Homeotic transformation best explains the results. H. sapiens and O. princeps show propensity for caudal shift at the sacral-caudal border (i.e., homeotic transformation of the first caudal vertebra to a sacral vertebra). Caudal and cranial shift among presacral vertebrae increases or decreases this propensity, respectively. Increase in number of sacral vertebrae in H. sapiens by homeotic transformation reduces pelvic outlet capacity and can be obstetrically hazardous. Anat Rec, 300:798-809, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Chondromalacia of trochlear notch after healing of olecranon stress fracture: a case report.

PubMed

Lu, Cheng-Chang; Chen, Shen-Kai; Wang, Chih-Wei; Chou, Pei-Hsi

2006-05-01

Chondromalacia of the trochlear notch and stress fracture of olecranon are uncommon injuries in the throwing athletes. We report an 18-year-old high school pitcher who had persistent postero-lateral elbow pain after a healed olecranon stress fracture of the right elbow. Diagnostic arthroscopy revealed chondromalacia of the trochlear notch. After treatment with arthroscopic drilling and abrasion chondroplasty, he returned to competitive pitching 1 year later postsurgery. This rare association between chondromalacia and stress fracture of the olecranon has not been reported previously in the literatures. Chondromalacia of the trochlear notch should be included as a differential diagnosis in evaluating athletes with persistent elbow pain after healed olecranon stress fractures.

Probability of stress-corrosion fracture under random loading

NASA Technical Reports Server (NTRS)

Yang, J. N.

1974-01-01

Mathematical formulation is based on cumulative-damage hypothesis and experimentally-determined stress-corrosion characteristics. Under both stationary random loadings, mean value and variance of cumulative damage are obtained. Probability of stress-corrosion fracture is then evaluated, using principle of maximum entropy.

Epidemiology of stress fracture injuries among US high school athletes, 2005-2006 through 2012-2013.

PubMed

Changstrom, Bradley G; Brou, Lina; Khodaee, Morteza; Braund, Cortney; Comstock, R Dawn

2015-01-01

High school athletes in the United States sustain millions of injuries annually, approximately 10% of which are fractures. However, there is no clear estimate of the number of stress fractures sustained by high school athletes annually despite reports that stress fractures account for 0.7% to 20% of injuries seen in sports medicine clinics. This suggests a high utilization of resources for a potentially preventable injury. In addition, stress fractures have been associated with low energy availability and disordered eating in young athletes, highlighting the importance of early recognition and intervention. To investigate stress fracture rates and patterns in a large national sample of US high school athletes. Descriptive epidemiologic study. Data from High School RIO (Reporting Information Online), a national sports injury surveillance study, were analyzed to describe rates and patterns of stress fracture injury sustained from 2005-2006 through 2012-2013, across sports and by sex. From 2005-2006 through 2012-2013, a total of 51,773 injuries were sustained during 25,268,873 athlete-exposures, of which 389 (0.8%) were stress fractures, resulting in an overall stress fracture rate of 1.54 per 100,000 athlete-exposures. Rates per 100,000 athlete-exposures were highest in girls' cross country (10.62), girls' gymnastics (7.43), and boys' cross country (5.42). In sex-comparable sports, girls sustained more stress fractures (63.3%) than did boys (36.7%) and had higher rates of stress fracture (2.22 vs 1.27; rate ratio, 1.75; 95% CI, 1.38-2.23). The most commonly injured sites were the lower leg (40.3% of all stress fractures), foot (34.9%), and lower back/lumbar spine/pelvis (15.2%). Management was nonsurgical in 98.7% of the cases, and 65.3% of injuries resulted in ≥3 weeks of time loss, medical disqualification, or an end to the season before athletes could return to play. Although a rare injury, stress fractures cause considerable morbidity for high school athletes

The incidence and distribution of stress fractures in elite tennis players

PubMed Central

Maquirriain, J; Ghisi, J P

2006-01-01

Background Modern professional tennis involves powerful movements repeatedly subjecting the musculoskeletal system to heavy mechanical load. Thus tennis players are exposed to high risk of overuse injuries including stress fractures. Objective To determine the incidence and distribution of stress fractures in elite tennis players. Study design Retrospective cohort study. Methods The cohort study population consisted of 139 elite players (mean (SD) age, 20.0 (5.0) years; 48 female, 91 male). Stress fractures were identified and confirmed radiologically from medical records during a two year period. Injuries were analysed according to age, sex, site, severity, delay in diagnosis, and time needed to return to sports. Results 15 players sustained 18 stress fractures, corresponding to an overall case incidence of 12.9% (95% confidence interval (CI), 8.1 to 20.0). The tarsal navicular was most affected (n = 5; 27%), followed by the pars interarticularis (n = 3; 16%), the metatarsals (n = 3; 16%), the tibia (n = 2; 11%) and the lunate (n = 2; 11%). Magnetic resonance imaging showed a greater incidence of “high grade” lesions (94.4%). Stress fracture incidence was significantly higher in juniors (20.3% (95% CI, 11.4 to 33.2)) than in professional players (7.5% (2.8 to 15.6)) (p = 0.045). Conclusions There was a high absolute risk (12.9%) of stress fractures in elite tennis players over a two year period. Junior players were at highest risk. The lesions are a major cause of disruption both of training and of competition. Risk factors should therefore be identified and prevention emphasised. PMID:16632579

Association of stressful life events with incident falls and fractures in older men: the Osteoporotic Fractures in Men (MrOS) Study

PubMed Central

Fink, Howard A.; Kuskowski, Michael A.; Marshall, Lynn M.

2014-01-01

Background: small, retrospective studies suggest that major life events and/or sudden emotional stress may increase fall and fracture risk. The current study examines these associations prospectively. Methods: a total of 5,152 men aged ≥65 years in the Osteoporotic Fractures in Men study self-reported data on stressful life events for 1 year prior to study Visit 2. Incident falls and fractures were ascertained for 1 year after Visit 2. Fractures were centrally confirmed. Results: a total of 2,932 (56.9%) men reported ≥1 type of stressful life event. In men with complete stressful life event, fall and covariate data (n = 3,949), any stressful life event was associated with a 33% increased risk of incident fall [relative risk (RR) 1.33, 95% confidence interval (CI) 1.19–1.49] and 68% increased risk of multiple falls (RR = 1.68, 95% CI = 1.40–2.01) in the year following Visit 2 after adjustment for age, education, Parkinson's disease, diabetes, stroke, instrumental activities of daily living (IADL) impairment, chair stand time, walk speed, multiple past falls, depressive symptoms and antidepressant use. Risk increased with the number of types of stressful life events. Though any stressful life event was associated with a 58% increased age-adjusted risk for incident fracture, this association was attenuated and no longer statistically significant after additional adjustment for total hip bone mineral density, fracture after age 50, Parkinson's disease, stroke and IADL impairment. Conclusions: in this cohort of older men, stressful life events significantly increased risk of incident falls independent of other explanatory variables, but did not independently increase incident fracture risk. PMID:24002237

Bilateral chronic sacral neuromodulation for treatment of lower urinary tract dysfunction.

PubMed

Hohenfellner, M; Schultz-Lampel, D; Dahms, S; Matzel, K; Thüroff, J W

1998-09-01

Chronic sacral neuromodulation aims at functional restoration of selected forms of nonneurogenic and neurogenic bladder dysfunction. The original technique, as described by Tanagho and Schmidt, provides unilateral sacral nerve stimulation via an implanted stimulator powering an electrode inserted into a sacral foramen. Its drawback was that the implant failed unpredictably in some patients despite previous successful percutaneous test stimulation. Therefore, we modified the stimulation technique to improve the efficacy of chronic sacral neuromodulation. Guarded bipolar electrodes powered by an implantable neurostimulator were attached bilaterally directly to the S3 nerves through a sacral laminectomy in 9 women and 2 men (mean age 43.4 years). Of the patients 5 had urinary incontinence due to detrusor hyperactivity and 6 had urinary retention from detrusor hypocontractility. Mean followup with repeated urodynamics was 13 months (range 9 to 28). Four significant complications were encountered in 4 patients. In 10 patients the urological sequelae of the neurological disorder were alleviated significantly (50% or more), including 5 who experienced complete relief of symptoms. The efficacy of chronic sacral neuromodulation can be improved by bilateral attachment of electrodes directly to the sacral nerves.

Sacral neuromodulation for women with Fowler's syndrome.

PubMed

Swinn, M J; Kitchen, N D; Goodwin, R J; Fowler, C J

2000-10-01

Neuromodulation of the sacral nerves has been found to be an effective therapy for a variety of lower urinary tract dysfunctions. The reported success rate for the period of trial stimulation (peripheral nerve evaluation test) prior to permanent implantation of a sacral nerve stimulator is variable, but generally reported to be in the region of 30-50%. We present here the results of the peripheral nerve evaluation test in 38 patients with urinary retention. 34 of the 38 had been found to have an abnormality of their striated urethral sphincter on electromyography using a concentric needle electrode, i.e., they had the disorder which was described by Fowler and coworkers in 1988. The overall success rate in this group was 68%. We believe that our relatively high success rate is due to sacral neuromodulation working via a mechanism which involves the urethral sphincter, an abnormality which had been demonstrated in 89% of these patients. Twelve of the patients subsequently underwent permanent implantation of a sacral nerve stimulator, and all of them have experienced a return of voiding. However, in 2 patients, there is a persisting need for self-catheterization. There is, however, a high reoperation rate.

Determination of In-Situ Stresses Around Underground Excavations by Means of Hydraulic Fracturing

DTIC Science & Technology

inhomogeneous, precracked variable rock is suitable for hydraulic fracturing as a method of in-situ stress measurement. It was found that basically the Coeur...d’Alene quartzite is amenable to hydraulic fracturing testing. The rock has no consistent anisotropy, but is inhomogeneous with physical property...horizontal stress notwithstanding rock condition. Field stress measurements in the Coeur d’Alene mines using the hydraulic fracturing technique are recommended.

Risk Stratification of Stress Fractures and Prediction of Return to Duty

DTIC Science & Technology

2015-12-01

enrollment. In study Task 1 we aim to determine the sex- and race -ethnicity-specific bone traits that may contribute to stress fracture risk in military...SUBJECT TERMS bone microarchitecture, HRpQCT, race , gender, sex, bone mineral density, vBMD, bone geometry, stress fracture 16. SECURITY...sectional study aimed at identifying the bone properties that may be related to the well-known sex and race /ethnicity differences in risk for stress

When do anterior external or internal fixators provide additional stability in an unstable (Tile C) pelvic fracture? A biomechanical study.

PubMed

Mcdonald, E; Theologis, A A; Horst, P; Kandemir, U; Pekmezci, M

2015-12-01

This study aimed at evaluating the additional stability that is provided by anterior external and internal fixators in an unstable pelvic fracture model (OTA 61-C). An unstable pelvic fracture (OTA 61-C) was created in 27 synthetic pelves by making a 5-mm gap through the sacral foramina (posterior injury) and an ipsilateral pubic rami fracture (anterior injury). The posterior injury was fixed with either a single iliosacral (IS) screw, a single trans-iliac, trans-sacral (TS) screw, or two iliosacral screws (S1S2). Two anterior fixation techniques were utilized: external fixation (Ex-Fix) and supra-acetabular external fixation and internal fixation (In-Fix); supra-acetabular pedicle screws connected with a single subcutaneous spinal rod. The specimens were tested using a nondestructive single-leg stance model. Peak-to-peak (P2P) displacement and rotation and conditioning displacement (CD) were calculated. The Ex-Fix group failed in 83.3 % of specimens with concomitant single-level posterior fixation (Total: 15/18-7 of 9 IS fixation, 8 of 9 TS fixation), and 0 % (0/9) of specimens with concomitant two-level (S1S2) posterior fixation. All specimens with the In-Fix survived testing except for two specimens treated with In-Fix combined with IS fixation. Trans-sacral fixation had higher pubic rotation and greater sacral and pubic displacement than S1S2 (p < 0.05). Rotation of the pubis and sacrum was not different between In-Fix constructs combined with single-level IS and TS fixation. In this model of an unstable pelvic fracture (OTA 61-C), anterior fixation with an In-Fix was biomechanically superior to an anterior Ex-Fix in the setting of single-level posterior fixation. There was no biomechanical difference between the In-Fix and Ex-Fix when each was combined with two levels of posterior sacral fixation.

Surgical treatment of refractory tibial stress fractures in elite dancers: a case series.

PubMed

Miyamoto, Ryan G; Dhotar, Herman S; Rose, Donald J; Egol, Kenneth

2009-06-01

Treatment of tibial stress fractures in elite dancers is centered on rest and activity modification. Surgical intervention in refractory cases has important implications affecting the dancers' careers. Refractory tibial stress fractures in dancers can be treated successfully with drilling and bone grafting or intramedullary nailing. Case series; Level of evidence, 4. Between 1992 and 2006, 1757 dancers were evaluated at a dance medicine clinic; 24 dancers (1.4%) had 31 tibial stress fractures. Of that subset, 7 (29.2%) elite dancers with 8 tibial stress fractures were treated operatively with either intramedullary nailing or drilling and bone grafting. Six of the patients were followed up closely until they were able to return to dance. One patient was available only for follow-up phone interview. Data concerning their preoperative treatment regimens, operative procedures, clinical union, radiographic union, and time until return to dance were recorded and analyzed. The mean age of the surgical patients at the time of stress fracture was 22.6 years. The mean duration of preoperative symptoms before surgical intervention was 25.8 months. Four of the dancers were male and 3 were female. All had failed nonoperative treatment regimens. Five patients (5 tibias) underwent drilling and bone grafting of the lesion, and 2 patients (3 tibias) with completed fractures or multiple refractory stress fractures underwent intramedullary nailing. Clinical union was achieved at a mean of 6 weeks and radiographic union at 5.1 months. Return to full dance activity was at an average of 6.5 months postoperatively. Surgical intervention for tibial stress fractures in dancers who have not responded to nonoperative management allowed for resolution of symptoms and return to dancing with minimal morbidity.

Incidentally diagnosed giant invasive sacral schwannoma

PubMed Central

Togral, Guray; Arikan, Murat; Hasturk, Askin E.; Gungor, Safak

2014-01-01

Schwannomas are benign encapsulated tumors of Schwan cells that grow slowly along the peripheral myelin nerve fibers. Sacral spinal schwannomas are very rare, and the incidence of sacral schwannoma ranges from 1-5% of all spinal schwannomas, and only around 50 cases are reported in the literature. There are 3 defined types of sacral schwannomas. These are retroperitoneal or presacral, intra osseous, and spinal schwannomas. Patients commonly present with complaints of pain and paresthesia due to the spinal schwannoma extending to extra spinal tissues. Direct x-ray, CT, MRI, and scintigraphy are used for preoperative diagnosis and treatment planning. Local recurrence and transformation to malignancy is very rare. For this reason, the frequently preferred treatments are subtotal removal of the mass or simple enucleation. In our article, we discuss the clinical features and the surgical treatment we performed without the need for stabilization in an incidentally determined giant invasive schwannoma case. PMID:24983285

Identification of natural fractures and in situ stress at Rantau Dedap geothermal field

NASA Astrophysics Data System (ADS)

Artyanto, Andika; Sapiie, Benyamin; Idham Abdullah, Chalid; Permana Sidik, Ridwan

2017-12-01

Rantau Dedap Area is a geothermal field which is located in Great Sumatra Fault (GSF). The fault and fracture are main factor in the permeability of the geothermal system. However, not all faults and fractures have capability of to flow the fluids. Borehole image log is depiction of the borehole conditions, it is used to identify the natural fractures and drilling induced fracture. Both of them are used to identify the direction of the fracture, direction of maximum horizontal stress (SHmax), and geomechanics parameters. The natural fractures are the results of responses to stress on a rock and permeability which controlling factor in research area. Breakouts is found in this field as a trace of drilling induced fracture due to in situ stress work. Natural fractures are strongly clustered with true strike trending which first, second, and third major direction are N170°E - N180°E (N-S), N60°E - N70°E (NE-SW), and N310°E - N320°E (NW-SE), while the dominant dip is 80° -90°. Based on borehole breakout analysis, maximum horizontal stress orientation is identified in N162°E - N204°E (N-S) and N242°E (NE-SW) direction. It’s constantly similar with regional stress which is affected by GSF. Several parameters have been identified and analyzed are SHmax, SHmin, and Sy. It can be concluded that Rantau Dedap Geothermal Field is affected by strike-slip regime. The determination of in situ stress and natural fractures are important to study the pattern of permeability which is related to the fault in reservoir of this field.

Stress-induced, time-dependent fracture closure at hydrothermal conditions

USGS Publications Warehouse

Beeler, N.M.; Hickman, S.H.

2004-01-01

Time-dependent closure of fractures in quartz was measured in situ at 22-530??C temperature and 0.1-150 MPa water pressure. Unlike previous crack healing and rock permeability studies, in this study, fracture aperture is monitored directly and continuously using a windowed pressure vessel, a long-working-distance microscope, and reflected-light interferometry. Thus the fracture volume and geometry can be measured as a function of time, temperature, and water pressure. Relatively uniform closure occurs rapidly at temperatures and pressures where quartz becomes significantly soluble in water. During closure the aperture is reduced by as much as 80% in a few hours. We infer that this closure results from the dissolution of small particles or asperities that prop the fracture open. The driving force for closure via dissolution of the prop is the sum of three chemical potential terms: (1) the dissolution potential, proportional to the logarithm of the degree of undersaturation of the solution; (2) the coarsening potential, proportional to the radius of curvature of the prop; and (3) the pressure solution potential, proportional to the effective normal stress at the contact between propping particles and the fracture wall. Our observations suggest that closure is controlled by a pressure solution-like process. The aperture of dilatant fractures and microcracks in the Earth that are similar to those in our experiments, such as ones generated from thermal stressing or brittle failure during earthquake rupture and slip, will decrease rapidly with time, especially if the macroscopic stress is nonhydrostatic.

Stress-induced, time-dependent fracture closure at hydrothermal conditions

NASA Astrophysics Data System (ADS)

Beeler, N. M.; Hickman, S. H.

2004-02-01

Time-dependent closure of fractures in quartz was measured in situ at 22-530°C temperature and 0.1-150 MPa water pressure. Unlike previous crack healing and rock permeability studies, in this study, fracture aperture is monitored directly and continuously using a windowed pressure vessel, a long-working-distance microscope, and reflected-light interferometry. Thus the fracture volume and geometry can be measured as a function of time, temperature, and water pressure. Relatively uniform closure occurs rapidly at temperatures and pressures where quartz becomes significantly soluble in water. During closure the aperture is reduced by as much as 80% in a few hours. We infer that this closure results from the dissolution of small particles or asperities that prop the fracture open. The driving force for closure via dissolution of the prop is the sum of three chemical potential terms: (1) the dissolution potential, proportional to the logarithm of the degree of undersaturation of the solution; (2) the coarsening potential, proportional to the radius of curvature of the prop; and (3) the pressure solution potential, proportional to the effective normal stress at the contact between propping particles and the fracture wall. Our observations suggest that closure is controlled by a pressure solution-like process. The aperture of dilatant fractures and microcracks in the Earth that are similar to those in our experiments, such as ones generated from thermal stressing or brittle failure during earthquake rupture and slip, will decrease rapidly with time, especially if the macroscopic stress is nonhydrostatic.

Value of lateral blood pool imaging in patients with suspected stress fractures of the tibia.

PubMed

Mohan, Hosahalli K; Clarke, Susan E M; Centenara, Martin; Lucarelli, Amanda; Baron, Daniel; Fogelman, Ignac

2011-03-01

To critically evaluate the use of lateral blood pool imaging in athletes with lower limb pain and with a clinical suspicion of stress fracture. Two experienced nuclear medicine physicians evaluated 3-phase bone scans using 99mTc-methylene diphosphonate performed in 50 consecutive patients referred from a specialist sports injury clinic for suspected tibial stress fracture. The vascularity to the tibia as seen on the blood pool (second phase) images in the anterior/posterior views was compared with the lateral/medial view assessments. Stress fractures were presumed to be present when on the delayed images (third phase) there was a focal or fusiform area of increased tracer uptake involving the tibial cortex. Shin splints which are a recognized cause of lower limb pain in athletes mimicking stress fracture were diagnosed if increased tracer uptake was seen extending along the posterior tibial surface with no significant focal or fusiform area of uptake within this. Inter-reviewer agreement for the assessment of vascularity was also assessed using Cohen's Kappa scores. Twenty-four stress fractures in 24 patients and 66 shin splints in 40 patients were diagnosed. In 18 patients stress fracture and shin splints coexisted. In 10 patients no tibial pathology was identified. Of the 24 patients diagnosed with stress fractures, lateral/medial blood pool imaging was superior in the assessment of blood pool activity (P < 0.001) identifying increased vascularity in 21 cases compared with the anterior/posterior views positive in only 11 cases. The inter-reviewer agreement was near perfect for lateral/medial views, κ = 0.86 while very good for anterior/posterior views, κ = 0.68. In patients with suspected tibial stress fractures, lateral views of the tibia provide the optimal method for evaluation of vascularity. Prospective studies with quantitative or semi-quantitative assessment of skeletal vascularity could provide supplementary information relating to the pathophysiology

Biomechanical Factors in Tibial Stress Fractures

DTIC Science & Technology

2004-08-01

these runners. A "stiff’ runner will spend less time in contact with the ground (Farley and Gonzalez, 1996 ) and will attenuate less shock between the...leg and the head (McMahon et al., 1987). This is in agreement with the findings of Farley and Gonzalez ( 1996 ) who suggested lower extremity stiffness...Crossley, K. ( 1996 ) Stress fractures: a review of 180 cases. Clin. J. Sport Med. 6, 85-89. Brudvig, T., Grudger, T. and Obermeyer, L. (1983) Stress

Distinct hip and rearfoot kinematics in female runners with a history of tibial stress fracture.

PubMed

Milner, Clare E; Hamill, Joseph; Davis, Irene S

2010-02-01

Cross-sectional controlled laboratory study. To investigate the kinematics of the hip, knee, and rearfoot in the frontal and transverse planes in female distance runners with a history of tibial stress fracture. Tibial stress fractures are a common overuse injury in runners, accounting for up to half of all stress fractures. Abnormal kinematics of the lower extremity may contribute to abnormal musculoskeletal load distributions, leading to an increased risk of stress fractures. Thirty female runners with a history of tibial stress fracture were compared to 30 age-matched and weekly-running-distance-matched control subjects with no previous lower extremity bony injuries. Kinematic and kinetic data were collected using a motion capture system and a force platform, respectively, as subjects ran in the laboratory. Selected variables of interest were compared between the groups using a multivariate analysis of variance (MANOVA). Peak hip adduction and peak rearfoot eversion angles were greater in the stress fracture group compared to the control group. Peak knee adduction and knee internal rotation angles and all joint angles at impact peak were similar between the groups. Runners with a previous tibial stress fracture exhibited greater peak hip adduction and rearfoot eversion angles during the stance phase of running compared to healthy controls. A consequence of these mechanics may be altered load distribution within the lower extremity, predisposing individuals to stress fracture.

Stress-Induced Fracturing of Reservoir Rocks: Acoustic Monitoring and μCT Image Analysis

NASA Astrophysics Data System (ADS)

Pradhan, Srutarshi; Stroisz, Anna M.; Fjær, Erling; Stenebråten, Jørn F.; Lund, Hans K.; Sønstebø, Eyvind F.

2015-11-01

Stress-induced fracturing in reservoir rocks is an important issue for the petroleum industry. While productivity can be enhanced by a controlled fracturing operation, it can trigger borehole instability problems by reactivating existing fractures/faults in a reservoir. However, safe fracturing can improve the quality of operations during CO2 storage, geothermal installation and gas production at and from the reservoir rocks. Therefore, understanding the fracturing behavior of different types of reservoir rocks is a basic need for planning field operations toward these activities. In our study, stress-induced fracturing of rock samples has been monitored by acoustic emission (AE) and post-experiment computer tomography (CT) scans. We have used hollow cylinder cores of sandstones and chalks, which are representatives of reservoir rocks. The fracture-triggering stress has been measured for different rocks and compared with theoretical estimates. The population of AE events shows the location of main fracture arms which is in a good agreement with post-test CT image analysis, and the fracture patterns inside the samples are visualized through 3D image reconstructions. The amplitudes and energies of acoustic events clearly indicate initiation and propagation of the main fractures. Time evolution of the radial strain measured in the fracturing tests will later be compared to model predictions of fracture size.

"Lucy" (A.L. 288-1) had five sacral vertebrae.

PubMed

Russo, Gabrielle A; Williams, Scott A

2015-02-01

A "long-backed" scenario of hominin vertebral evolution posits that early hominins possessed six lumbar vertebrae coupled with a high frequency of four sacral vertebrae (7:12-13:6:4), a configuration acquired from a hominin-panin last common ancestor (PLCA) having a vertebral formula of 7:13:6-7:4. One founding line of evidence for this hypothesis is the recent assertion that the "Lucy" sacrum (A.L. 288-1an, Australopithecus afarensis) consists of four sacral vertebrae and a partially-fused first coccygeal vertebra (Co1), rather than five sacral vertebrae as in modern humans. This study reassesses the number of sacral vertebrae in Lucy by reexamining the distal end of A.L.288-1an in the context of a comparative sample of modern human sacra and Co1 vertebrae, and the sacrum of A. sediba (MH2). Results demonstrate that, similar to S5 in modern humans and A. sediba, the last vertebra in A.L. 288-1an exhibits inferiorly-projecting (right side) cornua and a kidney-shaped inferior body articular surface. This morphology is inconsistent with that of fused or isolated Co1 vertebrae in humans, which either lack cornua or possess only superiorly-projecting cornua, and have more circularly-shaped inferior body articular surfaces. The level at which the hiatus' apex is located is also more compatible with typical five-element modern human sacra and A. sediba than if only four sacral vertebrae are present. Our observations suggest that A.L. 288-1 possessed five sacral vertebrae as in modern humans; thus, sacral number in "Lucy" does not indicate a directional change in vertebral count that can provide information on the PLCA ancestral condition. © 2015 Wiley Periodicals, Inc.

Developmental identity versus typology: Lucy has only four sacral segments.

PubMed

Machnicki, Allison L; Lovejoy, C Owen; Reno, Philip L

2016-08-01

Both interspecific and intraspecific variation in vertebral counts reflect the action of patterning control mechanisms such as Hox. The preserved A.L. 288-1 ("Lucy") sacrum contains five fused elements. However, the transverse processes of the most caudal element do not contact those of the segment immediately craniad to it, leaving incomplete sacral foramina on both sides. This conforms to the traditional definition of four-segmented sacra, which are very rare in humans and African apes. It was recently suggested that fossilization damage precludes interpretation of this specimen and that additional sacral-like features of its last segment (e.g., the extent of the sacral hiatus) suggest a general Australopithecus pattern of five sacral vertebrae. We provide updated descriptions of the original Lucy sacrum. We evaluate sacral/coccygeal variation in a large sample of extant hominoids and place it within the context of developmental variation in the mammalian vertebral column. We report that fossilization damage did not shorten the transverse processes of the fifth segment of Lucy's sacrum. In addition, we find that the extent of the sacral hiatus is too variable in apes and hominids to provide meaningful information on segment identity. Most importantly, a combination of sacral and coccygeal features is to be expected in vertebrae at regional boundaries. The sacral/caudal boundary appears to be displaced cranially in early hominids relative to extant African apes and humans, a condition consistent with the likely ancestral condition for Miocene hominoids. While not definitive in itself, a four-segmented sacrum accords well with the "long-back" model for the Pan/Homo last common ancestor. Am J Phys Anthropol 160:729-739, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

[A boy with a painful knee: bone tumour or stress fracture?].

PubMed

Robben, Bart J; Jutte, Paul C

2012-01-01

The symptoms of a stress fracture are almost identical to those of most bone tumours. Even with the use of various imaging techniques, it can be difficult to establish the correct diagnosis. Although a primary bone tumour requires early treatment to improve its prognosis, the discriminative factor in the diagnosis of a stress fracture is its clinical development over time. A 10-year-old boy was referred to our outpatient clinic on the suspicion of a primary bone tumour in his right tibia. A case was once described in this journal in which a stress fracture had eventually led to an amputation. The suspicion of primary bone tumour often marks the start of a long and intense diagnostic course. A stress fracture is the major diagnostic pitfall when there is a suspicion of such a tumour. If doubts persist after a diagnostic work-up by imaging, consultation with the Bone Tumour Committee is indicated. The patient can also be quickly referred to a centre specialised in treating bone tumours, as was the case in this article.

What questionnaires to use when measuring quality of life in sacral tumor patients: the updated sacral tumor survey.

PubMed

van Wulfften Palthe, Olivier D R; Janssen, Stein J; Wunder, Jay S; Ferguson, Peter C; Wei, Guo; Rose, Peter S; Yaszemski, Micheal J; Sim, Franklin H; Boland, Patrick J; Healey, John H; Hornicek, Francis J; Schwab, Joseph H

2017-05-01

Patient-reported outcomes are becoming increasingly important when investigating results of patient and disease management. In sacral tumor, the symptoms of patients can vary substantially; therefore, no single questionnaire can adequately account for the full spectrum of symptoms and disability. The purpose of this study is to analyze redundancy within the current sacral tumor survey and make a recommendation for an updated version based on the results and patient and expert opinions. A survey study from a tertiary care orthopedic oncology referral center was used. The patient sample included 70 patients with sacral tumors (78% chordoma). The following 10 questionnaires included in the current sacral tumor survey were evaluated: the Patient-Reported Outcomes Measurement Information System (PROMIS) Global Item short form, PROMIS Pain Intensity short form, PROMIS Pain Interference short form, PROMIS Neuro-QOL v1.0 Lower Extremity Function short form, PROMIS v1.0 Anxiety short form, the PROMIS v1.0 Depression short form, the International Continence Society Male short form, the Modified Obstruction-Defecation Syndrome questionnaire, the PROMIS Sexual Function Profile v1.0, and the Stoma Quality of Life tool. We performed an exploratory factor analysis to calculate the possible underlying latent traits. Spearman rank correlation coefficients were used to measure to what extent the questionnaires converged. We hypothesized the existence of six domains based on current literature: mental health, physical health, pain, gastrointestinal symptoms, sexual function, and urinary incontinence. To assess content validity, we surveyed 32 patients, 9 orthopedic oncologists, 1 medical oncologist, 1 radiation oncologist, and 1 orthopedic oncology nurse practitioner with experience in treating sacral tumor patients on the relevance of the domains. Reliability as measured by Cronbach alpha ranged from 0.65 to 0.96. Coverage measured by floor and ceiling effects ranged from 0% to 52

What Questionnaires To Use When Measuring Quality Of Life In Sacral Tumor Patients? The Updated Sacral Tumor Survey

PubMed Central

van Wulfften Palthe, Olivier D.R.; Janssen, Stein J.; Wunder, Jay S.; Ferguson, Peter C.; Wei, Guo; Rose, Peter. S.; Yaszemski, Micheal J.; Sim, Franklin H.; Boland, Patrick J.; Healey, John H.; Hornicek, Francis J.; Schwab, Joseph H.

2017-01-01

Background context Patient reported outcomes are becoming increasingly important when investigating results of patient and disease management. In sacral tumor patients symptoms can vary substantially, therefore no single questionnaire can adequately account for the full spectrum of symptoms and disability. Purpose The purpose of this study is to analyze redundancy within the current sacral tumor survey and make a recommendation for an updated version based on the results and patient and expert opinions. Study design/setting A survey study from a tertiary care orthopaedic oncology referral center was used for this study. Patient sample The patient sample included 70 patients with sacral tumors (78% chordoma). Outcome measures The following ten questionnaires included in the current sacral tumor survey were evaluated: the Patient Reported Outcomes Measurement Information System (PROMIS) Global Item short form, PROMIS Pain Intensity short form, PROMIS Pain Interference short form, PROMIS Neuro-QOL v1.0 Lower Extremity Function short form, PROMIS v1.0 Anxiety short form, the PROMIS v1.0 Depression short form, the International Continence Society (ICS) Male short form, the Modified Obstruction-Defecation Syndrome (MODS) questionnaire, the PROMIS Sexual Function Profile v1.0, and The Stoma Quality Of Life tool. Methods We performed an exploratory factor analysis to calculate possible underlying latent traits. Spearman rank correlation coefficients were used to measure to what extent the questionnaires converged. We hypothesized the existence of six domains based on current literature: mental health, physical health, pain, gastrointestinal symptoms, sexual function, and urinary incontinence. To assess content validity, we surveyed 32 patients, nine orthopaedic oncologists, one medical oncologist, one radiation oncologist, and an orthopaedic oncology nurse practitioner with experience in treating sacral tumor patients on the relevance of the domains. Results Reliability as

Preventive osteopathic manipulative treatment and stress fracture incidence among collegiate cross-country athletes.

PubMed

Brumm, Lynn F; Janiski, Carrie; Balawender, Jenifer L; Feinstein, Adam

2013-12-01

Stress fractures are common among athletes, particularly distance runners, with many theories regarding the etiologic process of stress fractures and various studies identifying risk factors or suggesting preventive techniques. To our knowledge, no previous studies have discussed the possible causative effects of somatic dysfunction or the preventive capabilities of osteopathic manipulative treatment (OMT). To apply a preventive OMT protocol for cross-country athletes to reduce the incidence of stress fractures. Cohort study. Examinations of cross-country athletes at an NCAA (National Collegiate Athletic Association) Division I university were performed by supervising physician-examiners and first- and second-year osteopathic medical students during several consecutive academic years. Athletes re-enrolled in the study each year they continued to be eligible. The intervention included osteopathic structural examination and OMT that focused on somatic dysfunction identified in the pelvis, sacrum, and lower extremities. More than 1800 participant examinations were performed on 124 male and female participants by 3 supervising physician-examiners and 141 osteopathic medical students over the course of 5 consecutive academic years (2004-2005 to 2008-2009). Data from these academic years were compared with data from the previous 8 academic years (1996-1997 to 2003-2004). An average of 20 new participants enrolled yearly. The number of annual stress fractures per team ranged from 0 to 6 for male participants and 1 to 6 for female participants. The cumulative annual incidence of stress fractures for male participants demonstrated a statistically significant decrease from 13.9% (20 of 144) before intervention to 1.0% (1 of 105) after intervention, resulting in a 98.7% relative reduction in stress-fracture diagnosis (P=.019). The cumulative annual incidence for female participants showed a minimal decrease from 12.9% (23 of 178) before intervention to 12.0% (17 of 142) after

Biomechanical Concepts for Fracture Fixation

PubMed Central

Bottlang, Michael; Schemitsch, Christine E.; Nauth, Aaron; Routt, Milton; Egol, Kenneth; Cook, Gillian E.; Schemitsch, Emil H.

2015-01-01

Application of the correct fixation construct is critical for fracture healing and long-term stability; however, it is a complex issue with numerous significant factors. This review describes a number of common fracture types, and evaluates their currently available fracture fixation constructs. In the setting of complex elbow instability, stable fixation or radial head replacement with an appropriately sized implant in conjunction with ligamentous repair is required to restore stability. For unstable sacral fractures, “standard” iliosacral screw fixation is not sufficient for fractures with vertical or multiplanar instabilities. Periprosthetic femur fractures, in particular Vancouver B1 fractures, have increased stability when using 90/90 fixation versus a single locking plate. Far Cortical Locking combines the concept of dynamization with locked plating in order to achieve superior healing of a distal femur fracture. Finally, there is no ideal construct for syndesmotic fracture stabilization; however, these fractures should be fixed using a device that allows for sufficient motion in the syndesmosis. In general, orthopaedic surgeons should select a fracture fixation construct that restores stability and promotes healing at the fracture site, while reducing the potential for fixation failure. PMID:26584263

The impact of in-situ stress and outcrop-based fracture geometry on hydraulic aperture and upscaled permeability in fractured reservoirs

NASA Astrophysics Data System (ADS)

Bisdom, Kevin; Bertotti, Giovanni; Nick, Hamidreza M.

2016-10-01

Aperture has a controlling impact on porosity and permeability and is a source of uncertainty in modeling of naturally fractured reservoirs. This uncertainty results from difficulties in accurately quantifying aperture in the subsurface and from a limited fundamental understanding of the mechanical and diagenetic processes that control aperture. In the absence of cement bridges and high pore pressure, fractures in the subsurface are generally considered to be closed. However, experimental work, outcrop analyses and subsurface data show that some fractures remain open, and that aperture varies even along a single fracture. However, most fracture flow models consider constant apertures for fractures. We create a stress-dependent heterogeneous aperture by combining Finite Element modeling of discrete fracture networks with an empirical aperture model. Using a modeling approach that considers fractures explicitly, we quantify equivalent permeability, i.e. combined matrix and stress-dependent fracture flow. Fracture networks extracted from a large outcropping pavement form the basis of these models. The results show that the angle between fracture strike and σ1 has a controlling impact on aperture and permeability, where hydraulic opening is maximum for an angle of 15°. At this angle, the fracture experiences a minor amount of shear displacement that allows the fracture to remain open even when fluid pressure is lower than the local normal stress. Averaging the heterogeneous aperture to scale up permeability probably results in an underestimation of flow, indicating the need to incorporate full aperture distributions rather than simplified aperture models in reservoir-scale flow models.

Fracture toughness and the effects of stress state on fracture of nickel aluminides

NASA Technical Reports Server (NTRS)

Lewandowski, John J.; Michal, Gary M.; Locci, Ivan; Rigney, Joseph D.

1991-01-01

The effects of stress state on the fracture behavior of Ni3Al, Ni3Al + B, and NiAl were determined using either notched or fatigue-precracked bend bars tested to failure at room temperature, in addition to testing specimens in tension under superposed hydrostatic pressure. Although Ni3Al is observed to fail in a macroscopically brittle intergranular manner in tension tests conducted at room temperature, the fracture toughnesses presently obtained on Ni3Al exceeded 20 MPam, and R-curve behavior was exhibited. In situ monitoring of the fracture experiments was utilized to aid in interpreting the source(s) of the high toughness in Ni3Al, while SEM fractography was utilized to determine the operative fracture modes. The superposition by hydrostatic pressure during tensile testing of NiAl specimens was observed to produce increased ductility without changing the fracture mode.

Direct Imaging of Natural Fractures and Stress Compartments Stimulated by Hydraulic Fracturing

NASA Astrophysics Data System (ADS)

Lacazette, A.; Vermilye, J. M.

2014-12-01

This contribution will present results from passive seismic studies of hydraulic fracture treatments in North American and Asian basins. One of the key data types is a comparatively new surface-based seismic imaging product - "Tomographic Fracture Images®" (TFI®). The procedure is an extension of Seismic Emission Tomography (SET), which is well-established and widely used. Conventional microseismic results - microearthquake hypocenter locations, magnitudes, and focal mechanism solutions - are also obtained from the data via a branch of the processing workflow. TFI is accomplished by summing the individual time steps in a multidimensional SET hypervolume over extended periods of time, such as an entire frac stage. The dimensions of a SET hypervolume are the X, Y, and Z coordinates of the voxels, the time step (typically on the order of 100 milliseconds), and the seismic activity value. The resulting summed volume is skeletonized to produce images of the main fracture surfaces, which are known to occupy the maximum activity surfaces of the high activity clouds from theory, field studies, and experiments. The orientation vs. area of the resulting TFIs can be analyzed in detail and compared with independent data sets such as volumetric structural attributes from reflection seismic data and borehole fracture data. We find that the primary effect of hydraulic fracturing is to stimulate preexisting natural fracture networks and faults. The combination of TFIs with hypocenter distributions and microearthquake focal mechanisms provides detailed information on subsurface stress compartmentalization. Faults are directly imaged which allows discrimination of fault planes from auxiliary planes of focal mechanism solutions. Examples that will be shown include simultaneous movement on a thrust fault and tear fault and examples of radically different stress compartments (e.g. extensional vs. wrench faulting) stimulated during a single hydraulic fracture treatment. The figure

Stress fractures in athletes. How to spot this underdiagnosed injury.

PubMed

Sallis, R E; Jones, K

1991-05-01

Stress fractures are an increasingly common injury in competitive athletes, especially runners. Amenorrheic athletes are at particularly high risk. A radionuclide bone scan should be considered when the index of suspicion for stress fracture is high. Plain radiographs are of little use in establishing the diagnosis in the early stages of the injury. Early diagnosis and prompt institution of conservative therapy allow for a favorable outcome in most cases. Avoidance of or reduced participation in the inciting activity is important for pain control. Certain stress fractures, such as those involving the femoral neck, should be monitored closely and treated aggressively with internal fixation when conservative measures fail. Runners who have exercise-induced amenorrhea should be advised to decrease their training intensity to a level where menses resume. Cyclic therapy with conjugated estrogens and progesterone should also be considered, as should daily calcium supplementation.

The Israeli elite infantry recruit: a model for understanding the biomechanics of stress fractures.

PubMed

Milgrom, C

1989-01-01

In a series of prospective studies among infantry recruits the biomechanics of stress fractures have been studied. In this recruit model bone geometry and the natural shock absorbers of the body have been found to be related to stress fracture morbidity. Using the technique of accelerometry in this model, it has been shown that in the fatigue state shock absorption decreases, resulting in an increase in the amplitude of vertical accelerations that propagate up the skeleton at heel strike. Experiments to study the possibility of lowering stress fracture morbidity in this model by means of viscoelastic orthotics have been successful only in the case of femoral and metatarsal stress fractures among certain subpopulations. Stress fracture management in this model has been improved by early detection and by treatment regimens according to a protocol that emphasizes limited rest periods to allow healing to take place rather than judging recovery by pain levels.

Prophylactic Sacral Dressing for Pressure Ulcer Prevention in High-Risk Patients.

PubMed

Byrne, Jaime; Nichols, Patricia; Sroczynski, Marzena; Stelmaski, Laurie; Stetzer, Molly; Line, Cynthia; Carlin, Kristen

2016-05-01

Patients in intensive care units are likely to have limited mobility owing to hemodynamic instability and activity orders for bed rest. Bed rest is indicated because of the severity of the disease process, which often involves intubation, sedation, paralysis, surgical procedures, poor nutrition, low flow states, and poor circulation. These patients are predisposed to the development and/or the progression of pressure ulcers not only because of their underlying diseases, but also because of limited mobility and deconditioned states of health. To assess whether treating high-risk patients with a prophylactic sacral dressing decreases the incidence of unit-acquired sacral pressure ulcers. An evidence-based tool for identifying patients at high risk for pressure ulcers was used in 3 intensive care units at an urban tertiary care hospital and academic medical center. Those patients deemed at high risk had a prophylactic sacral dressing applied. Incidence rates were collected and compared for the 7 months preceding use of the dressings and for 7 months during the trial period when the dressing was used. After the sacral dressing began being used, the number of unit-acquired sacral pressure ulcers decreased by 3.4 to 7.6 per 1000 patient days depending on the unit. A prophylactic sacral dressing may help prevent unit-acquired sacral pressure ulcers. Implementation of an involved care team with heightened awareness and increased education along with a prophylactic sacral dressing in patients deemed high risk for skin breakdown are all essential for success. ©2016 American Association of Critical-Care Nurses.

Differentiating Stress Fracture From Periostitis.

PubMed

Martire, J R

1994-10-01

In brief Even in the age of high-technology MRI and CT, the triple-phase bone scan (TPBS) remains an exceptionally useful and accurate tool in evaluating athletic injuries. This is perhaps best seen in active people with overuse injuries of the tibia, femur, or humerus when plain films are negative but bone pain persists. Differentiating periostitis from stress fracture requires analyzing distinctive TPBS appearances and patterns.

Predicting Fluid Flow in Stressed Fractures: A Quantitative Evaluation of Methods

NASA Astrophysics Data System (ADS)

Weihmann, S. A.; Healy, D.

2015-12-01

Reliable estimation of fracture stability in the subsurface is crucial to the success of exploration and production in the petroleum industry, and also for wider applications to earthquake mechanics, hydrogeology and waste disposal. Previous work suggests that fracture stability is related to fluid flow in crystalline basement rocks through shear or tensile instabilities of fractures. Our preliminary scoping analysis compares the fracture stability of 60 partly open (apertures 1.5-3 cm) and electrically conductive (low acoustic amplitudes relative to matrix) fractures from a 16 m section of a producing zone in a basement well in Bayoot field, Yemen, to a non-producing zone in the same well (also 16 m). We determine the Critically Stressed Fractures (CSF; Barton et al., 1995) and dilatation tendency (Td; Ferrill et al., 1999). We find that: 1. CSF (Fig. 1) is a poor predictor of high fluid flow in the inflow zone; 88% of the fractures are predicted to be NOT critically stressed and yet they all occur within a zone of high fluid flow rate 2. Td (Fig. 2) is also a poor predictor of high fluid flow in the inflow zone; 67% of the fractures have a LOW Td(< 0.6) 3. For the non-producing zone CSF is a very reliable predictor (100% are not critically stressed) whereas the values of Tdare consistent with their location in non-producing interval (81% are < 0.6) (Fig. 3 & 4). In summary, neither method correlates well with the observed abundance of hydraulically conductive fractures within the producing zone. Within the non-producing zone CSF and Td make reasonably accurate predictions. Fractures may be filled or partially filled with drilling mud or a lower density and electrically conductive fill such as clay in the producing zone and therefore appear (partly) open. In situ stress, fluid pressure, rock properties (friction, strength) and fracture orientation data used as inputs for the CSF and Td calculations are all subject to uncertainty. Our results suggest that scope

Anterior tibial stress fractures treated with anterior tension band plating in high-performance athletes.

PubMed

Cruz, Alexandre Santa; de Hollanda, João Paris Buarque; Duarte, Aires; Hungria Neto, José Soares

2013-06-01

The non-surgical treatment of anterior tibial cortex stress fractures requires long periods of abstention from sports activities and often results in non-union. Many different surgical techniques have already been previously described to treat these fractures, but there is no consensus on the best treatment. We describe the outcome of treatment using anterior tibial tension band plating in three high-performance athletes (4 legs) with anterior tibial cortex stress fractures. Tibial osteosynthesis with a 3.5-mm locking compression plate in the anterolateral aspect of the tibia was performed in all patients diagnosed with anterior tibial stress fracture after September 2010 at Santa Casa Hospital. All of the fractures were consolidated within a period of 3 months after surgery, allowing for an early return to pre-injury levels of competitive sports activity. There were no infection, non-union, malunion or anterior knee pain complications. Anterior tibial tension band plating leads to prompt fracture consolidation and is a good alternative for the treatment of anterior tibial cortex stress fractures. Bone grafts were shown to be unnecessary.

The receptor tyrosine kinase RET regulates hindgut colonization by sacral neural crest cells.

PubMed

Delalande, Jean-Marie; Barlow, Amanda J; Thomas, Aaron J; Wallace, Adam S; Thapar, Nikhil; Erickson, Carol A; Burns, Alan J

2008-01-01

The enteric nervous system (ENS) is formed from vagal and sacral neural crest cells (NCC). Vagal NCC give rise to most of the ENS along the entire gut, whereas the contribution of sacral NCC is mainly limited to the hindgut. This, and data from heterotopic quail-chick grafting studies, suggests that vagal and sacral NCC have intrinsic differences in their ability to colonize the gut, and/or to respond to signalling cues within the gut environment. To better understand the molecular basis of these differences, we studied the expression of genes known to be essential for ENS formation, in sacral NCC within the chick hindgut. Our results demonstrate that, as in vagal NCC, Sox10, EdnrB, and Ret are expressed in sacral NCC within the gut. Since we did not detect a qualitative difference in expression of these ENS genes we performed DNA microarray analysis of vagal and sacral NCC. Of 11 key ENS genes examined from the total data set, Ret was the only gene identified as being highly differentially expressed, with a fourfold increase in expression in vagal versus sacral NCC. We also found that over-expression of RET in sacral NCC increased their ENS developmental potential such that larger numbers of cells entered the gut earlier in development, thus promoting the fate of sacral NCC towards that of vagal NCC.

Stress fracture and premenstrual syndrome in Japanese adolescent athletes: a cross-sectional study.

PubMed

Takeda, Takashi; Imoto, Yoko; Nagasawa, Hiroyo; Takeshita, Atsuko; Shiina, Masami

2016-10-18

To investigate the relationship between the occurrence of stress fracture and premenstrual syndrome (PMS)/premenstrual dysphoric disorder (PMDD) in Japanese adolescent athletes. Cross-sectional study. Osaka, Japan. A school-based survey on menstruation and school life was conducted using a sample of 1818 Japanese female students who belonged to two public high schools in Japan. Among them, we recruited 394 athletes who had regular menstrual cycles (25-38 days) and completed a questionnaire about their premenstrual symptoms and their competitive career. Premenstrual symptoms and the occurrence of stress fracture. The prevalences of moderate-to-severe PMS and PMDD were 8.9% and 1.3%, respectively, which were the same as in collegiate athletes in a previous study. Premenstrual symptoms disturbed 'Work efficiency or productivity, home responsibilities', 'Relationships with coworkers or family' and 'Athletic performance in training or competition' more severely than menstrual pain (p=0.031, p=0.004 and p<0.001, respectively). 66 athletes (16.8%) reported having experienced a stress fracture. The severity of 'Overeating or food cravings', 'Physical symptoms' and 'Performance in training or competition' in athletes with previous stress fractures were much higher than in those without a history of stress fractures (p=0.015, p=0.008 and p=0.006, respectively). In terms of premenstrual symptoms, 'Physical symptoms' was associated with an increased risk of stress fractures in athletes (OR 1.66, 95% CI 1.06 to 2.62). The results from this study indicated that premenstrual symptoms may affect athletic performance and has the risk of stress fractures in adolescent athletes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Greater Polar Moment of Inertia at the Tibia in Athletes Who Develop Stress Fractures

PubMed Central

Weidauer, Lee A.; Binkley, Teresa; Vukovich, Matt; Specker, Bonny

2014-01-01

Background: Several previous investigations have determined potential risk factors for stress fractures in athletes and military personnel. Purpose: To determine factors associated with the development of stress fractures in female athletes. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 88 female athletes (cross-country, n = 29; soccer, n = 15; swimming, n = 9; track and field, n = 14; volleyball, n = 12; and basketball, n = 9) aged 18 to 24 years were recruited to participate in a longitudinal bone study and had their left distal tibia at the 4%, 20%, and 66% sites scanned by peripheral quantitative computed tomography (pQCT). Patients included 23 athletes who developed stress fractures during the following year (cases). Whole body, hip, and spine scans were obtained using dual-energy x-ray absorptiometry (DXA). Analysis of covariance was used to determine differences in bone parameters between cases and controls after adjusting for height, lower leg length, lean mass, fat mass, and sport. Results: No differences were observed between cases and controls in any of the DXA measurements. Cases had significantly greater unadjusted trabecular bone mineral content (BMC), greater polar moment of inertia (PMI) at the 20% site, and greater cortical BMC at the 66% site; however, after adjusting for covariates, the differences became nonsignificant. When analyses were repeated using all individuals who had ever had a stress fracture as cases (n = 31) and after controlling for covariates, periosteal circumference was greater in the cases than the controls (71.1 ± 0.7 vs 69.4 ± 0.5 mm, respectively; P = .04). Conclusion: A history of stress fractures is associated with larger bones. These findings are important because larger bones were previously reported to be protective against fractures and stress fractures, but study findings indicate that may not always be true. One explanation could be that individuals who sustain stress fractures have

Greater Polar Moment of Inertia at the Tibia in Athletes Who Develop Stress Fractures.

PubMed

Weidauer, Lee A; Binkley, Teresa; Vukovich, Matt; Specker, Bonny

2014-07-01

Several previous investigations have determined potential risk factors for stress fractures in athletes and military personnel. To determine factors associated with the development of stress fractures in female athletes. Case-control study; Level of evidence, 3. A total of 88 female athletes (cross-country, n = 29; soccer, n = 15; swimming, n = 9; track and field, n = 14; volleyball, n = 12; and basketball, n = 9) aged 18 to 24 years were recruited to participate in a longitudinal bone study and had their left distal tibia at the 4%, 20%, and 66% sites scanned by peripheral quantitative computed tomography (pQCT). Patients included 23 athletes who developed stress fractures during the following year (cases). Whole body, hip, and spine scans were obtained using dual-energy x-ray absorptiometry (DXA). Analysis of covariance was used to determine differences in bone parameters between cases and controls after adjusting for height, lower leg length, lean mass, fat mass, and sport. No differences were observed between cases and controls in any of the DXA measurements. Cases had significantly greater unadjusted trabecular bone mineral content (BMC), greater polar moment of inertia (PMI) at the 20% site, and greater cortical BMC at the 66% site; however, after adjusting for covariates, the differences became nonsignificant. When analyses were repeated using all individuals who had ever had a stress fracture as cases (n = 31) and after controlling for covariates, periosteal circumference was greater in the cases than the controls (71.1 ± 0.7 vs 69.4 ± 0.5 mm, respectively; P = .04). A history of stress fractures is associated with larger bones. These findings are important because larger bones were previously reported to be protective against fractures and stress fractures, but study findings indicate that may not always be true. One explanation could be that individuals who sustain stress fractures have greater loading that results in greater periosteal circumference

Outcomes of Surgical Treatment for Anterior Tibial Stress Fractures in Athletes: A Systematic Review.

PubMed

Chaudhry, Zaira S; Raikin, Steven M; Harwood, Marc I; Bishop, Meghan E; Ciccotti, Michael G; Hammoud, Sommer

2017-12-01

Although most anterior tibial stress fractures heal with nonoperative treatment, some may require surgical management. To our knowledge, no systematic review has been conducted regarding surgical treatment strategies for the management of chronic anterior tibial stress fractures from which general conclusions can be drawn regarding optimal treatment in high-performance athletes. This systematic review was conducted to evaluate the surgical outcomes of anterior tibial stress fractures in high-performance athletes. Systematic review; Level of evidence, 4. In February 2017, a systematic review of the PubMed, MEDLINE, Cochrane, SPORTDiscus, and CINAHL databases was performed to identify studies that reported surgical outcomes for anterior tibial stress fractures. Articles meeting the inclusion criteria were screened, and reported outcome measures were documented. A total of 12 studies, published between 1984 and 2015, reporting outcomes for the surgical treatment of anterior tibial stress fractures were included in this review. All studies were retrospective case series. Collectively, surgical outcomes for 115 patients (74 males; 41 females) with 123 fractures were evaluated in this review. The overall mean follow-up was 23.3 months. The most common surgical treatment method reported in the literature was compression plating (n = 52) followed by drilling (n = 33). Symptom resolution was achieved in 108 of 123 surgically treated fractures (87.8%). There were 32 reports of complications, resulting in an overall complication rate of 27.8%. Subsequent tibial fractures were reported in 8 patients (7.0%). Moreover, a total of 17 patients (14.8%) underwent a subsequent procedure after their initial surgery. Following surgical treatment for anterior tibial stress fracture, 94.7% of patients were able to return to sports. The available literature indicates that surgical treatment of anterior tibial stress fractures is associated with a high rate of symptom resolution and return

Sacroplasty for Symptomatic Sacral Hemangioma: A Novel Treatment Approach

PubMed Central

Agarwal, V.; Sreedher, G.; Weiss, K.R.; Hughes, M.A.

2013-01-01

Summary Painful vertebral body hemangiomas have been successfully treated with vertebroplasty and kyphoplasty. Sacral hemangiomas are uncommon and as such painful sacral hemangiomas are rare entities. We report what we believe is only the second successful treatment of a painful sacral hemangioma with CT-guided sacroplasty. A 56-year-old woman with a history of right-sided total hip arthroplasty and lipoma excision presented to her orthopedic surgeon with persistent right-sided low back pain which radiated into her buttock and right groin and hindered her ability to walk and perform her activities of daily living. MRIs of the thoracic spine, lumbar spine and pelvis showed numerous lesions with imaging characteristics consistent with multiple hemangiomas including a 2.2×2.1 cm lesion involving the right sacrum adjacent to the right S1 neural foramen. Conservative measures including rest, physical therapy, oral analgesics and right-sided sacroiliac joint steroid injection did not provide significant relief. Given her lack of improvement and the fact that her pain localized to the right sacrum, the patient underwent CT-guided sacroplasty for treatment of a painful right sacral hemangioma. Under CT fluoroscopic guidance, a 10 gauge introducer needle was advanced through the soft tissues of the back to the margin of the lesion. Biopsy was then performed and after appropriate preparation, cement was then introduced through the needle using a separate cement filler cannula. Appropriate filling of the right sacral hemangioma was visualized using intermittent CT fluoroscopy. After injection of approximately 2.5 cc of cement, it was felt that there was near complete filling of the right sacral hemangioma. With satisfactory achievement of cement filling, the procedure was terminated. Pathology from biopsy taken at the time of the procedure was consistent with hemangioma. Image-guided sacroplasty with well-defined endpoints is an effective, minimally invasive and safe

Fractured rock stress-permeability relationships from in situ data and effects of temperature and chemical-mechanical couplings

DOE PAGES

Rutqvist, J.

2014-09-19

The purpose of this paper is to (i) review field data on stress-induced permeability changes in fractured rock; (ii) describe estimation of fractured rock stress-permeability relationships through model calibration against such field data; and (iii) discuss observations of temperature and chemically mediated fracture closure and its effect on fractured rock permeability. The field data that are reviewed include in situ block experiments, excavation-induced changes in permeability around tunnels, borehole injection experiments, depth (and stress) dependent permeability, and permeability changes associated with a large-scale rock-mass heating experiment. Data show how the stress-permeability relationship of fractured rock very much depends on localmore » in situ conditions, such as fracture shear offset and fracture infilling by mineral precipitation. Field and laboratory experiments involving temperature have shown significant temperature-driven fracture closure even under constant stress. Such temperature-driven fracture closure has been described as thermal overclosure and relates to better fitting of opposing fracture surfaces at high temperatures, or is attributed to chemically mediated fracture closure related to pressure solution (and compaction) of stressed fracture surface asperities. Back-calculated stress-permeability relationships from field data may implicitly account for such effects, but the relative contribution of purely thermal-mechanical and chemically mediated changes is difficult to isolate. Therefore, it is concluded that further laboratory and in situ experiments are needed to increase the knowledge of the true mechanisms behind thermally driven fracture closure, and to further assess the importance of chemical-mechanical coupling for the long-term evolution of fractured rock permeability.« less

Fractured rock stress-permeability relationships from in situ data and effects of temperature and chemical-mechanical couplings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rutqvist, J.

The purpose of this paper is to (i) review field data on stress-induced permeability changes in fractured rock; (ii) describe estimation of fractured rock stress-permeability relationships through model calibration against such field data; and (iii) discuss observations of temperature and chemically mediated fracture closure and its effect on fractured rock permeability. The field data that are reviewed include in situ block experiments, excavation-induced changes in permeability around tunnels, borehole injection experiments, depth (and stress) dependent permeability, and permeability changes associated with a large-scale rock-mass heating experiment. Data show how the stress-permeability relationship of fractured rock very much depends on localmore » in situ conditions, such as fracture shear offset and fracture infilling by mineral precipitation. Field and laboratory experiments involving temperature have shown significant temperature-driven fracture closure even under constant stress. Such temperature-driven fracture closure has been described as thermal overclosure and relates to better fitting of opposing fracture surfaces at high temperatures, or is attributed to chemically mediated fracture closure related to pressure solution (and compaction) of stressed fracture surface asperities. Back-calculated stress-permeability relationships from field data may implicitly account for such effects, but the relative contribution of purely thermal-mechanical and chemically mediated changes is difficult to isolate. Therefore, it is concluded that further laboratory and in situ experiments are needed to increase the knowledge of the true mechanisms behind thermally driven fracture closure, and to further assess the importance of chemical-mechanical coupling for the long-term evolution of fractured rock permeability.« less

Couple stresses and the fracture of rock.

PubMed

Atkinson, Colin; Coman, Ciprian D; Aldazabal, Javier

2015-03-28

An assessment is made here of the role played by the micropolar continuum theory on the cracked Brazilian disc test used for determining rock fracture toughness. By analytically solving the corresponding mixed boundary-value problems and employing singular-perturbation arguments, we provide closed-form expressions for the energy release rate and the corresponding stress-intensity factors for both mode I and mode II loading. These theoretical results are augmented by a set of fracture toughness experiments on both sandstone and marble rocks. It is further shown that the morphology of the fracturing process in our centrally pre-cracked circular samples correlates very well with discrete element simulations. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Sacral neuromodulation for lower urinary tract dysfunction.

PubMed

Van Kerrebroeck, Philip E V; Marcelissen, Tom A T

2012-08-01

To review the technique, indications, results and working mechanisms of sacral neuromodulation (SNM) for lower urinary tract dysfunction. The available literature on SNM for lower urinary tract dysfunction was searched. Based on the information available in the literature and also based on personal experience, the urological indications, technique, mechanisms of action and results of SNM are presented and discussed. SNM for lower urinary tract dysfunction involves stimulation of the 3rd sacral nerve with an electrode implanted in the sacral foramen and connected to a pulse generator. The technique is accepted by the FDA since 1997. Currently, SNM for lower urinary tract dysfunction has been successfully used in about 26,000 patients with various forms of lower urinary tract dysfunction, including urgency, frequency and urgency incontinence as well as non-obstructive urinary retention. The actual procedure of SNM consists of a minimal invasive technique and is effective in about 70% of the patients who have been implanted with a permanent system. Also, in pelvic pain, interesting results have been described. SNM modulates the micturition reflexes at different levels in the central nervous system. Sacral neuromodulation is a safe and effective therapy for various forms of lower urinary tract dysfunction, including urgency, frequency and urgency incontinence as well as non-obstructive urinary retention. It should be the first choice after failure of maximal conservative therapy.

Thermal stresses, differential subsidence, and flexure at oceanic fracture zones

NASA Technical Reports Server (NTRS)

Wessel, Pal; Haxby, William F.

1990-01-01

Geosat geoid undulations over four Pacific fracture zones have been analyzed. After correcting for the isostatic thermal edge effect, the amplitudes of the residuals are shown to be proportional to the age offset. The shape of the residuals seems to broaden with increasing age. Both geoid anomalies and available ship bathymetry data suggest that slip must sometimes occur on the main fracture zone or secondary faults. Existing models for flexure at fracture zones cannot explain the observed anomalies. A combination model accounting for slip and including flexure from thermal stresses and differential subsidence is presented. This model accounts for lateral variations in flexural rigidity from brittle and ductile yielding due to both thermal and flexural stresses and explains both the amplitudes and the shape of the anomalies along each fracture zone. The best fitting models have mechanical plate thicknesses that are described by the depth to the 600-700 C isotherms.

Rehabilitation and return to running after lower limb stress fractures.

PubMed

Liem, Brian C; Truswell, Hallie J; Harrast, Mark A

2013-01-01

Lower limb stress fractures are common injuries in runners. In terms of treatment, much of the medical literature has focused primarily on rest and cessation of running, but little has been written about the rehabilitation and functional progression of runners following a lower limb stress fracture. This article reviews the scientific evidence behind common rehabilitation concepts used for runners recovering from these injuries and also discusses sport-specific training modalities such as deep water running and antigravity treadmill training. Overall this article is intended to be a practical resource for clinicians to guide runners in functional rehabilitation and return to running following lower limb stress injury.

Stress fractures of the ribs and upper extremities: causation, evaluation, and management.

PubMed

Miller, Timothy L; Harris, Joshua D; Kaeding, Christopher C

2013-08-01

Stress fractures are common troublesome injuries in athletes and non-athletes. Historically, stress fractures have been thought to predominate in the lower extremities secondary to the repetitive stresses of impact loading. Stress injuries of the ribs and upper extremities are much less common and often unrecognized. Consequently, these injuries are often omitted from the differential diagnosis of rib or upper extremity pain. Given the infrequency of this diagnosis, few case reports or case series have reported on their precipitating activities and common locations. Appropriate evaluation for these injuries requires a thorough history and physical examination. Radiographs may be negative early, requiring bone scintigraphy or MRI to confirm the diagnosis. Nonoperative and operative treatment recommendations are made based on location, injury classification, and causative activity. An understanding of the most common locations of upper extremity stress fractures and their associated causative activities is essential for prompt diagnosis and optimal treatment.

Safety and effectiveness of percutaneous sacroplasty: a single-centre experience in 58 consecutive patients with tumours or osteoporotic insufficient fractures treated under fluoroscopic guidance.

PubMed

Pereira, Licia Pacheco; Clarençon, Frédéric; Cormier, Evelyne; Rose, Michèle; Jean, Beatrix; Le Jean, Lise; Chiras, Jacques

2013-10-01

To report our experience in percutaneous sacroplasty (PSP) for tumours and insufficiency fractures of the sacrum. Single-centre retrospective analysis of 58 consecutive patients who underwent 67 PSPs for intractable pain from sacral tumours (84.5 %) or from osteoporotic fractures (15.5 %). The following data were assessed: visual analogue scale (VAS) before and after the procedure for global pain; short-term (1-month) clinical follow-up using a four-grade patient satisfaction scale (worse, unchanged, mild improvement and significant improvement); modification in analgesics consumption; referred short-term walking mobility. Minor and major complications were systematically assessed. The mean VAS score was 5.3 ± 2.0 in pre-procedure and 1.7 ± 1.8 in post-procedure. At 1-month follow-up, 34/58 (58.5 %) patients experienced a mild improvement; 15/58 (26 %) presented a significant improvement while 4/58 (7 %) and 5/58 (8.5 %) patients had unchanged or worse pain, respectively. Decreased analgesic consumption was observed in 34 % (20/58) of the patients. Eighty percent of patients with walking limitation experienced improvement, 16 % remained unchanged and 4 % were worse. We noted minor complications in 2/58 patients (3.4 %) and major complications in 2/58 patients (3.4 %). Percutaneous sacroplasty for metastatic and osteoporotic fractures is a safe and effective technique in terms of pain relief and functional outcome. • Percutaneous sacroplasty provides pain relief and functional improvement for insufficiency sacral fractures. • Percutaneous sacroplasty provides pain relief and function improvement for sacral tumours. • The major complication rate is acceptable (3.4 %), and is higher in sacral tumours. • Posterior wall/cortical sacral bone disruption is not statistically associated with more complications. • However, osteolytic tumours seem to be associated with higher risk of complications.

Inelastic and Dynamic Fracture and Stress Analyses

NASA Technical Reports Server (NTRS)

Atluri, S. N.

1984-01-01

Large deformation inelastic stress analysis and inelastic and dynamic crack propagation research work is summarized. The salient topics of interest in engine structure analysis that are discussed herein include: (1) a path-independent integral (T) in inelastic fracture mechanics, (2) analysis of dynamic crack propagation, (3) generalization of constitutive relations of inelasticity for finite deformations , (4) complementary energy approaches in inelastic analyses, and (5) objectivity of time integration schemes in inelastic stress analysis.

Fracture and Stress Evolution on Europa: New Insights Into Fracture Interpretation and Ice Thickness Estimates Using Fracture Mechanics Analyses

NASA Technical Reports Server (NTRS)

Kattenhorn, Simon

2004-01-01

The work completed during the funding period has provided many important insights into fracturing behavior in Europa's ice shell. It has been determined that fracturing through time is likely to have been controlled by the effects of nonsynchronous rotation stresses and that as much as 720 deg of said rotation may have occurred during the visible geologic history. It has been determined that there are at least two distinct styles of strike-slip faulting and that their mutual evolutionary styles are likely to have been different, with one involving a significant dilational component during shear motion. It has been determined that secondary fracturing in perturbed stress fields adjacent to older structures such as faults is a prevalent process on Europa. It has been determined that cycloidal ridges are likely to experience shear stresses along the existing segment portions as they propagate, which affects propagation direction and ultimately induces tailcracking at the segment tip than then initiates a new cycle of cycloid segment growth. Finally, it has been established that mechanical methods (e.g., flexure analysis) can be used to determine the elastic thickness of the ice shell, which, although probably only several km thick, is likely to be spatially variable, being thinner under bands but thicker under ridged plains terrain.

The association of novel polymorphisms with stress fracture injury in Elite Athletes: Further insights from the SFEA cohort.

PubMed

Varley, Ian; Hughes, David C; Greeves, Julie P; Stellingwerff, Trent; Ranson, Craig; Fraser, William D; Sale, Craig

2018-06-01

To determine, in conjunction with a wider investigation, whether 11 genetic variants in the vicinity of vitamin D, collagen and Wnt signalling pathways were associated with stress fracture injury in the Stress Fracture Elite Athlete (SFEA) cohort. Genotype-phenotype association study. Self-reported stress fracture history and demographic data were recorded in 518 elite athletes, 449 male and 69 female (mean age 24.2±5.5 years) from the SFEA cohort. Elite athletes were assigned to two groups based on history of stress fracture injury. Data were analysed for the whole cohort and sub-stratified in to male only and multiple stress fracture cases. Genotype was determined using a proprietary fluorescence-based competitive allele-specific polymerase chain reaction assay. SOST SNP rs1877632 and VDR SNPs rs10735810 and rs731236 were associated with stress fracture (p<0.05). In the whole cohort, rs1877632 heterozygotes and homozygotes of the rare allele combined made up 59% of stress fracture sufferers in comparison to 46% in the non-stress fracture group (p=0.05). In the multiple stress fracture cohort, homozygotes of the rare allele of rs10735810 and rs731236 showed an association with stress fracture when compared to those homozygotes for the common allele combined with heterozygotes (p=0.03; p=0.01). No significant associations were shown in the other SNPs analysed (p>0.05). These data suggest an important role for SOST SNP rs1877632 and VDR SNPs rs10735810 and rs731236 in the pathophysiology of stress fracture. This might be due to the role of the SNPs in the regulation of bone remodelling and adaptation to mechanical loading, with potential implications for the prevention and treatment of stress fracture injuries. Copyright © 2017. Published by Elsevier Ltd.

Introduction of laparoscopic sacral colpopexy to a fellowship training program.

PubMed

Kantartzis, Kelly; Sutkin, Gary; Winger, Dan; Wang, Li; Shepherd, Jonathan

2013-11-01

Minimally invasive sacral colpopexy has increased over the past decade, with many senior physicians adopting this new skill set. However, skill acquisition at an academic institution in the presence of postgraduate learners is not well described. This manuscript outlines the introduction of laparoscopic sacral colpopexy to an academic urogynecology service that was not performing minimally invasive sacral colpopexies, and it also defines a surgical learning curve. The first 180 laparoscopic sacral colpopexies done by four attending urogynecologists from January 2009 to December 2011 were retrospectively analyzed. The primary outcome was operative time. Secondary outcomes included conversion to laparotomy, estimated blood loss, and intra- and postoperative complications. Linear regression was used to analyze trends in operative times. Fisher's exact test compared surgical complications and counts of categorical variables. Mean total operative time was 250 ± 52 min (range 146-452) with hysterectomy and 222 ± 45 (range 146-353) for sacral colpopexy alone. When compared with the first ten cases performed by each surgeon, operative times in subsequent groups decreased significantly, with a 6-16.3% reduction in overall times. There was no significant difference in the rate of overall complications regardless of the number of prior procedures performed (p = 0.262). Introduction of laparoscopic sacral colpopexy in a training program is safe and efficient. Reduction in operative time is similar to published learning curves in teaching and nonteaching settings. Introducing this technique does not add additional surgical risk as these skills are acquired.

Latissimus dorsi free flap for coverage of sacral radiodermatitis in the ambulatory patient

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stark, D.; Tofield, J.J.; Terranova, W.

1987-07-01

Ambulatory patients with large sacral ulcers can represent extremely challenging coverage problems. Technical options become fewer when sacral ulcers are coupled with radiation dermatitis. Latissimus dorsi free flap transfer, with direct anastomoses to sacral vessels, is described in 2 patients.

In situ stress and fracture permeability along the Stillwater fault zone, Dixie Valley Nevada

USGS Publications Warehouse

Hickman, S.H.; Barton, C.A.; Zoback, M.D.; Morin, R.; Sass, J.; Benoit, R.

1997-01-01

Borehole televiewer and hydrologic logging and hydraulic fracturing stress measurements were carried out in a 2.7-km-deep geothermal production well (73B-7) drilled into the Stillwater fault zone. Precision temperature and spinner flowmeter logs were also acquired in well 73B-7, with and without simultaneously injecting water into the well. Localized perturbations to well-bore temperature and flow were used to identify hydraulically conductive fractures. Comparison of these data with fracture orientations from the televiewer log indicates that permeable fractures within and adjacent to the Stillwater fault zone are critically stressed, potentially active shear planes in the current west-northwest extensional stress regime at Dixie Valley.

Case report: multifocal subchondral stress fractures of the femoral heads and tibial condyles in a young military recruit.

PubMed

Yoon, Pil Whan; Yoo, Jeong Joon; Yoon, Kang Sup; Kim, Hee Joong

2012-03-01

Subchondral stress fractures of the femoral head may be either of the insufficiency-type with poor quality bone or the fatigue-type with normal quality bone but subject to high repetitive stresses. Unlike osteonecrosis, multiple site involvement rarely has been reported for subchondral stress fractures. We describe a case of multifocal subchondral stress fractures involving femoral heads and medial tibial condyles bilaterally within 2 weeks. A 27-year-old military recruit began having left knee pain after 2 weeks of basic training, without any injury. Subsequently, right knee, right hip, and left hip pain developed sequentially within 2 weeks. The diagnosis of multifocal subchondral stress fracture was confirmed by plain radiographs and MR images. Nonoperative treatment of the subchondral stress fractures of both medial tibial condyles and the left uncollapsed femoral head resulted in resolution of symptoms. The collapsed right femoral head was treated with a fibular strut allograft to restore congruity and healed without further collapse. There has been one case report in which an insufficiency-type subchondral stress fracture of the femoral head and medial femoral condyle occurred within a 2-year interval. Because the incidence of bilateral subchondral stress fractures of the femoral head is low and multifocal involvement has not been reported, multifocal subchondral stress fractures can be confused with multifocal osteonecrosis. Our case shows that subchondral stress fractures can occur in multiple sites almost simultaneously.

Bilateral stress fracture of the fibulae and periostitis of the tibiae.

PubMed

Tsuchie, Hiroyuki; Okada, Kyoji; Nagasawa, Hiroyuki; Chida, Shuichi; Shimada, Yoichi

2010-01-01

This study describes a unique case of bilateral stress fractures of the fibulae and provides a literature review. A 16-year-old female badminton player presented with pain around the bilateral distal lateral legs. She had mild bilateral varus deformity at the knee joint, and the bilateral ankles showed valgus deformity in standing posture. Radiographs and computed tomography showed periosteal reactions on the bilateral distal fibulae. Technetium-99m bone scintigraphy demonstrated increased uptake in the bilateral distal fibulae and the bilateral middle third of the tibiae. A diagnosis of bilateral distal fibular stress fractures was made. She was advised to stop playing badminton until the symptoms disappeared. Varus deformity of the knee and valgus deformity of the ankle may have influenced the mechanism underlying bilateral symmetric stress fractures. Copyright © 2010 S. Karger AG, Basel.

Stress fracture as a complication of autogenous bone graft harvest from the distal tibia.

PubMed

Chou, Loretta B; Mann, Roger A; Coughlin, Michael J; McPeake, William T; Mizel, Mark S

2007-02-01

Autogenous bone graft from the distal tibia provides cancellous bone graft for foot and ankle operations, and it has osteogenic and osteoconductive properties. The site is in close proximity to the foot and ankle, and published retrospective studies show low morbidity from the procedure. One-hundred autografts were obtained from the distal tibia between 2000 and 2003. In four cases the distal tibial bone graft harvest resulted in a stress fracture. There were three women and one man. The average time of diagnosis of the stress fracture from the operation was 1.8 months. All stress fractures healed with a short course (average 2.4 months) of cast immobilization. This study demonstrated that a stress fracture from the donor site of autogenous bone graft of the distal tibia occurs and can be successfully treated nonoperatively.

Repeated Stress Fractures in an Amenorrheic Marathoner: A Case Conference.

ERIC Educational Resources Information Center

Sutton, John R.; Nilson, Karen L.

1989-01-01

Presents a case conference by 2 experts on the relationship between a 26-year-old marathoner's amenorrhea and her sustained unusual stress fractures in 4 ribs (plus previous similar fractures of the calcaneal, navicular, metatarsal, and tibial bones). The experts conclude that she suffers many manifestations of overtraining. (SM)

Manubrial stress fractures diagnosed on MRI: report of two cases and review of the literature.

PubMed

Baker, Jonathan C; Demertzis, Jennifer L

2016-06-01

In contrast to widely-reported sternal insufficiency fractures, stress fractures of the sternum from overuse are extremely rare. Of the 5 cases of sternal stress fracture published in the English-language medical literature, 3 were in the sternal body and only 2 were in the manubrium. We describe two cases of manubrial stress fracture related to golf and weightlifting, and present the first report of the MR findings of this injury. In each of these cases, the onset of pain was atraumatic, insidious, and associated with increased frequency of athletic activity. Imaging was obtained because of clinical diagnostic uncertainty. On MRI, each patient had a sagittally oriented stress fracture of the lateral manubrium adjacent to the first rib synchondrosis. Both patients had resolution of pain after a period of rest, with subsequent successful return to their respective activities. One patient had a follow-up MRI, which showed resolution of the manubrial marrow edema and fracture line. Based on the sternal anatomy and MR findings, we hypothesize that this rare injury might be caused by repetitive torque of the muscle forces on the first costal cartilage and manubrium, and propose that MRI might be an effective means of diagnosing manubrial stress fracture.

Iliac screw for reconstructing posterior pelvic ring in Tile type C1 pelvic fractures.

PubMed

Li, Yonggang; Sang, Xiguang; Wang, Zhiyong; Cheng, Lin; Liu, Hao; Qin, Tao; Di, Kai

2018-06-18

It is often difficult to achieve stable fixation in Tile type C1 pelvic fractures and there is no standard fixation technique for these types of injuries. Iliac screw fixation can be used for treating Type C1 pelvic fractures. A retrospective review was performed on 47 patients who underwent iliac screw fixation in posterior column of ilium (PCI) for Tile type C1 pelvic fractures from July 2007 to December 2014. All patients were treated with fracture reduction, sacral nerve root decompression (if needed), internal fixation by iliac screw and connecting rod. The data on surgical time, intraoperative bleeding volume, postoperative neurologic functions and postoperative complications were analyzed. Patients were follow-up for at least 12months. The mean surgical time was 148minutes, and the mean intraoperative bleeding volume was 763ml. Patients were encouraged in-bed activities immediately after surgery. The postoperative Majeed functional score was 48-100 points (mean 80.2), corresponding to an excellent and good recovery of 91.5%. Postoperative X-radiographs and CT scans indicated satisfactory fracture reduction. Iliac screw fixation combined with sacral nerve canal decompression could effectively restore pelvic alignment and improve neurological functions for complex pelvic trauma. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Anterior sacral meningocele with presacral cysts: report of a case.

PubMed

Krivokapić, Zoran; Grubor, Nikica; Micev, Marjan; Colović, Radoje

2004-11-01

Anterior sacral meningocele is a rare anomaly most frequently presenting as a presacral mass. Since the first description in 1837, approximately 150 cases have been reported. The case presented is a 37-year-old female in whom an asymptomatic presacral mass was discovered during her first delivery. Because normal delivery was impossible, a cesarean section was performed. A year later, in a regional hospital a "cystic presacral tumor" was treated with biopsy and drainage. Four years later, she developed constipation caused by perineal compression for which she was admitted to our department in which two anterior presacral cysts were excised. The recovery was complicated with meningitis, which was successfully treated with antibiotics. Whenever a presacral mass is found, anterior sacral meningocele has to be a diagnostic consideration. The symptoms are usually related to the compression on rectum, bladder, and sacral nervous plexus. Rectal examination and radiography of the pelvis with the sacral bone showing the "scimitar sign" are the main diagnostic methods. Myelography, computed tomography, and magnetic resonance imaging are the best methods for identifying the precise anatomy of sacral meningocele and for proper planning of the operation. Transvaginal or transrectal aspiration and drainage are not advised, because they may result in a lethal outcome caused by sepsis.

The surgical management of sacral chordomas.

PubMed

Schwab, Joseph H; Healey, John H; Rose, Peter; Casas-Ganem, Jorge; Boland, Patrick J

2009-11-15

Retrospective case series. The purpose of this study was to evaluate factors that contribute to improved local control and survival. In addition, we sought to define the expected morbidity associated with treatment. Sacral chordomas are rare tumors presumed to arise from notochordal cells. Local recurrence presents a major problem in the management of these tumors and it has been correlated with survival. Resection of sacral tumors is associated with significant morbidity. Forty-two patients underwent resection for sacral chordoma between 1990 and 2005. Twelve patients had their initial surgery elsewhere. There were 12 female and 30 male patients. The proximal extent of the sacrectomy was at least S2 in 32 patients. Median survival was 84 months, and 5-year disease-free (DFS) and disease-specific survival (DSF) were 56% and 77%, respectively. Local recurrence (LR) and metastasis occurred in 17 (40%) and 13 (31%) patients, respectively. Local recurrence (P=0.0001), metastasis (P=0.0001), prior resection (P=0.046), and higher grade (P=0.05) were associated with a worse DSF. Prior resections (P=0.0001) and intralesional resections (P=0.01) were associated with a higher rate of LR. Intralesional resections were associated with a lower DSF (P=0.0001). Wide contaminated margins treated with cryosurgery and/or radiation were not associated with a higher LR rate. Rectus abdominus flaps were associated with decreased wound complications (P=0.01). Thirty-one (74%) patients reported that they self catheterize; and 16 (38%) patients required bowel training, while an additional twelve (29%) patients had a colostomy. Twenty-eight (67%) patients reported sexual dysfunction. Two (5%) patients died due to sepsis. Intralesional resection should be avoided as it is associated with a higher LR rate and worse survival. Rectus abdominus flaps ought to be considered as they lower the wound complication rate. Sacral resection is associated with significant morbidity.

Mechanisms underlying recurrent inhibition in the sacral parasympathetic outflow to the urinary bladder.

PubMed Central

de Groat, W C

1976-01-01

1. In cats with the sacral dorsal roots cut on one side electrical stimulation (15-40 c/s) of the central end of the transected ipsilateral pelvic nerve depressed spontaneous bladder contractions. The depression was abolished by transecting the ipsilateral sacral ventral roots. 2. Electrical stimulation of acutely or chronically transected ('deafferented') sacral ventral roots depressed spontaneous bladder contractions and the firing of sacral parasympathetic preganglionic neurones innervating the bladder. The depression of neuronal firing occurred ipsilateral and contralateral to the point of stimulation, but only occurred with stimulation of sacral roots containing preganglionic axons and only with stimulation of sacral roots containing preganglionic axons and only at intensities of stimulation (0-7-4V) above the threshold for activation of these axons. 3. The inhibitory responses were not abolished by strychnine administered by micro-electrophoresis to preganglionic neurones, but were blocked by the intravenous administration of strychnine. 4. The firing of preganglionic neurones elicited by micro-electrophoretic administration of an excitant amino acid (DL-homocysteic acid) was not depressed by stimulation of the ventral roots. 5. It is concluded that the inhibition of the sacral outflow to the bladder by stimulation of sacral ventral roots is related to antidromic activation of vesical preganglionic axons. Collaterals of these axons must excite inhibitory interneurones which in turn depress transmission at a site on the micturition reflex pathway prior to the preganglionic neurones. PMID:950603

Understanding the etiology of the posteromedial tibial stress fracture.

PubMed

Milgrom, Charles; Burr, David B; Finestone, Aharon S; Voloshin, Arkady

2015-09-01

Previous human in vivo tibial strain measurements from surface strain gauges during vigorous activities were found to be below the threshold value of repetitive cyclical loading at 2500 microstrain in tension necessary to reduce the fatigue life of bone, based on ex vivo studies. Therefore it has been hypothesized that an intermediate bone remodeling response might play a role in the development of tibial stress fractures. In young adults tibial stress fractures are usually oblique, suggesting that they are the result of failure under shear strain. Strains were measured using surface mounted unstacked 45° rosette strain gauges on the posterior aspect of the flat medial cortex just below the tibial midshaft, in a 48year old male subject while performing vertical jumps, staircase jumps and running up and down stadium stairs. Shear strains approaching 5000 microstrain were recorded during stair jumping and vertical standing jumps. Shear strains above 1250 microstrain were recorded during runs up and down stadium steps. Based on predictions from ex vivo studies, stair and vertical jumping tibial shear strain in the test subject was high enough to potentially produce tibial stress fracture subsequent to repetitive cyclic loading without necessarily requiring an intermediate remodeling response to microdamage. Copyright © 2015 Elsevier Inc. All rights reserved.

Dietary intake and stress fractures among elite male combat recruits.

PubMed

Moran, Daniel S; Heled, Yuval; Arbel, Yael; Israeli, Eran; Finestone, Aharon S; Evans, Rachel K; Yanovich, Ran

2012-03-13

Appropriate and sufficient dietary intake is one of the main requirements for maintaining fitness and health. Inadequate energy intake may have a negative impact on physical performance which may result in injuries among physically active populations. The purpose of this research was to evaluate a possible relationship between dietary intake and stress fracture occurrence among combat recruits during basic training (BT). Data was collected from 74 combat recruits (18.2 ± 0.6 yrs) in the Israeli Defense Forces. Data analyses included changes in anthropometric measures, dietary intake, blood iron and calcium levels. Measurements were taken on entry to 4-month BT and at the end of BT. The occurrence of stress reaction injury was followed prospectively during the entire 6-month training period. Twelve recruits were diagnosed with stress fracture in the tibia or femur (SF group). Sixty two recruits completed BT without stress fractures (NSF). Calcium and vitamin D intakes reported on induction day were lower in the SF group compared to the NSF group-38.9% for calcium (589 ± 92 and 964 ± 373 mg·d-1, respectively, p < 0.001), and-25.1% for vitamin D (117.9 ± 34.3 and 157.4 ± 93.3 IU·d-1, respectively, p < 0.001). During BT calcium and vitamin D intake continued to be at the same low values for the SF group but decreased for the NSF group and no significant differences were found between these two groups. The development of stress fractures in young recruits during combat BT was associated with dietary deficiency before induction and during BT of mainly vitamin D and calcium. For the purpose of intervention, the fact that the main deficiency is before induction will need special consideration.

Determining the minimum in situ stress from hydraulic fracturing through perforations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warpinski, N.R.

Hydraulic fracture stress measurements have been performed through perforations at depths from 1310 to 2470 m at the US Department of Energy's Multiwell Experiment site. The results of over sixty stress tests conducted through perforations have shown that small-volume hydraulic fractures generally provide an accurate, reproducible measurement of the minimum in situ stress. However, unusual behavior can occur in some tests and techniques to evaluate the behavior are suggested. Unclear instantaneous shut-in pressures, which are found on occasional tests, are difficult to evaluate, but the problem appears to be a complex stress state; reprocessing the data using log-log or othermore » functions does not necessarily provide the correct stress value. The possible error in such tests should be assessed from the original pressure-time data and not the reprocessing techniques. Stress results show that the stress distribution is dependent on lithology at this site; mudstones, shales and other nonreservoir rocks generally have a near-lithostatic stress, while sandstones have a considerably lower minimum stress value. 30 refs., 18 figs., 4 tabs.« less

Immediate effects of modified landing pattern on a probabilistic tibial stress fracture model in runners.

PubMed

Chen, T L; An, W W; Chan, Z Y S; Au, I P H; Zhang, Z H; Cheung, R T H

2016-03-01

Tibial stress fracture is a common injury in runners. This condition has been associated with increased impact loading. Since vertical loading rates are related to the landing pattern, many heelstrike runners attempt to modify their footfalls for a lower risk of tibial stress fracture. Such effect of modified landing pattern remains unknown. This study examined the immediate effects of landing pattern modification on the probability of tibial stress fracture. Fourteen experienced heelstrike runners ran on an instrumented treadmill and they were given augmented feedback for landing pattern switch. We measured their running kinematics and kinetics during different landing patterns. Ankle joint contact force and peak tibial strains were estimated using computational models. We used an established mathematical model to determine the effect of landing pattern on stress fracture probability. Heelstrike runners experienced greater impact loading immediately after landing pattern switch (P<0.004). There was an increase in the longitudinal ankle joint contact force when they landed with forefoot (P=0.003). However, there was no significant difference in both peak tibial strains and the risk of tibial stress fracture in runners with different landing patterns (P>0.986). Immediate transitioning of the landing pattern in heelstrike runners may not offer timely protection against tibial stress fracture, despite a reduction of impact loading. Long-term effects of landing pattern switch remains unknown. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fatigue Stress Fracture of the Talar Body: An Uncommon Cause of Ankle Pain.

PubMed

Kim, Young Sung; Lee, Ho Min; Kim, Jong Pil; Moon, Han Sol

2016-01-01

Fatigue stress fractures of the talus are rare and usually involve the head of the talus in military recruits. We report an uncommon cause of ankle pain due to a fatigue stress fracture of the body of the talus in a 32-year-old male social soccer player. Healing was achieved after weightbearing suppression for 6 weeks. Although rare, a stress fracture of the body of the talus should be considered in an athlete with a gradual onset of chronic ankle pain. Magnetic resonance imaging and bone scan are useful tools for early diagnosis. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Relationships among in-situ stress, fractures and faults, and fluid flow: Monterey formation, Santa Maria Basin, California

USGS Publications Warehouse

Finkbeiner, T.; Barton, C.A.; Zoback, M.D.

1997-01-01

We used borehole televiewer (BHTV) data from four wells within the onshore and offshore Santa Maria basin, California, to investigate the relationships among fracture distribution, orientation, and variation with depth and in-situ stress. Our analysis of stress-induced well-bore breakouts shows a uniform northeast maximum horizontal stress (SH max) orientation in each well. This direction is consistent with the SH max direction determined from well-bore breakouts in other wells in this region, the northwest trend of active fold axes, and kinematic inversion of nearby earthquake focal plane mechanisms. In contrast to the uniformity of the stress field, fracture orientation, dip, and frequency vary considerably from well to well and within each well. With depth, fractures can be divided into distinct subsets on the basis of fracture frequency and orientation, which correlate with changes of lithology and physical properties. Although factors such as tectonic history, diagenesis, and structural variations obviously have influenced fracture distribution, integration of the in-situ stress and fracture data sets indicates that many of the fractures, faults, and bedding planes are active, small-scale strike-slip and reverse faults in the current northeast-trending transpressive stress field. In fact, we observed local breakout rotations in the wells, providing kinematic evidence for recent shear motion along fracture and bedding-parallel planes. Only in the onshore well do steeply dipping fractures strike parallel to SHmax. Drill-stem tests from two of the offshore wells indicate that formation permeability is greatly enhanced in sections of the wells where fractures are favorably oriented for shear failure in the modern stress field. Thus, relatively small-scale active faults provide important conduits along which fluids migrate.

Stress fractures of the foot and ankle, part 2: site-specific etiology, imaging, and treatment, and differential diagnosis.

PubMed

Mandell, Jacob C; Khurana, Bharti; Smith, Stacy E

2017-09-01

Stress fractures of the foot and ankle are a commonly encountered problem among athletes and individuals participating in a wide range of activities. This illustrated review, the second of two parts, discusses site-specific etiological factors, imaging appearances, treatment options, and differential considerations of stress fractures of the foot and ankle. The imaging and clinical management of stress fractures of the foot and ankle are highly dependent on the specific location of the fracture, mechanical forces acting upon the injured site, vascular supply of the injured bone, and the proportion of trabecular to cortical bone at the site of injury. The most common stress fractures of the foot and ankle are low risk and include the posteromedial tibia, the calcaneus, and the second and third metatarsals. The distal fibula is a less common location, and stress fractures of the cuboid and cuneiforms are very rare, but are also considered low risk. In contrast, high-risk stress fractures are more prone to delayed union or nonunion and include the anterior tibial cortex, medial malleolus, navicular, base of the second metatarsal, proximal fifth metatarsal, hallux sesamoids, and the talus. Of these high-risk types, stress fractures of the anterior tibial cortex, the navicular, and the proximal tibial cortex may be predisposed to poor healing because of the watershed blood supply in these locations. The radiographic differential diagnosis of stress fracture includes osteoid osteoma, malignancy, and chronic osteomyelitis.

Stress fractures of the ribs in elite competitive rowers: a report of nine cases.

PubMed

Dragoni, S; Giombini, A; Di Cesare, A; Ripani, M; Magliani, G

2007-10-01

The objective was to report the clinical and imaging patterns of nine cases of stress fractures of the rib diagnosed in Italian Olympic rowers. Nine patients with stress fractures of the rib detected from 103 (8.7%) Italian team rowers competing between May 2000 and May 2006 were identified based on the database of a sports medicine institute. All athletes were male. They were aged between 17 and 31 years (mean: 24.4). Patient weight, fracture location, rowing side and imaging methods employed were noted. The diagnosis was made based on history, clinical examination and Tc-99m MDP bone scintigraphy. Eight of the 9 fractures were located anterolaterally between the fourth and ninth rib. In 1 of the 5 athletes with standard radiographs, a fracture line was visible and in 4 there was callus formation. In 2 athletes sonography was performed, which detected discontinuity of the rib surface and callus formation (1 case each). Stress fractures of the ribs are relatively common in competitive rowers. They are characterized by increasing lateral chest pain and typical scintigraphic, radiographic and sonographic findings.

In-situ stress and fracture permeability in a fault-hosted geothermal reservoir at Dixie Valley, Nevada

USGS Publications Warehouse

Hickman, Stephen; Barton, Colleen; Zoback, Mark; Morin, Roger; Sass, John; Benoit, Richard; ,

1997-01-01

As part of a study relating fractured rock hydrology to in-situ stress and recent deformation within the Dixie Valley Geothermal Field, borehole televiewer logging and hydraulic fracturing stress measurements were conducted in a 2.7-km-deep geothermal production well (73B-7) drilled into the Stillwater fault zone. Borehole televiewer logs from well 73B-7 show numerous drilling-induced tensile fractures, indicating that the direction of the minimum horizontal principal stress, Shmin, is S57 ??E. As the Stillwater fault at this location dips S50 ??E at approximately 3??, it is nearly at the optimal orientation for normal faulting in the current stress field. Analysis of the hydraulic fracturing data shows that the magnitude of Shmin is 24.1 and 25.9 MPa at 1.7 and 2.5 km, respectively. In addition, analysis of a hydraulic fracturing test from a shallow well 1.5 km northeast of 73B-7 indicates that the magnitude of Shmin is 5.6 MPa at 0.4 km depth. Coulomb failure analysis shows that the magnitude of Shmin in these wells is close to that predicted for incipient normal faulting on the Stillwater and subparallel faults, using coefficients of friction of 0.6-1.0 and estimates of the in-situ fluid pressure and overburden stress. Spinner flowmeter and temperature logs were also acquired in well 73B-7 and were used to identify hydraulically conductive fractures. Comparison of these stress and hydrologic data with fracture orientations from the televiewer log indicates that hydraulically conductive fractures within and adjacent to the Stillwater fault zone are critically stressed, potentially active normal faults in the current west-northwest extensional stress regime at Dixie Valley.

Spinopelvic dissociation: multidetector computed tomographic evaluation of fracture patterns and associated injuries at a single level 1 trauma center.

PubMed

Gupta, Pushpender; Barnwell, Jonathan C; Lenchik, Leon; Wuertzer, Scott D; Miller, Anna N

2016-06-01

The objective of the present study is to evaluate multidetector computed tomographic (MDCT) fracture patterns and associated injuries in patients with spinopelvic dissociation (SPD). Our institutional trauma registry database was reviewed from Jan. 1, 2006, to Sept. 30, 2012, specifically evaluating patients with sacral fractures. MDCT scans of patients with sacral fractures were reviewed to determine the presence of SPD. SPD cases were characterized into the following fracture patterns: U-shaped, Y-shaped, T-shaped, H-shaped, and burst. The following MDCT features were recorded: level of the horizontal fracture, location of vertical fracture, kyphosis between major fracture fragments, displacement of fracture fragment, narrowing of central spinal canal, narrowing of neural foramina, and extension into sacroiliac joints. Quantitative evaluation of the sacral fractures was performed in accordance with the consensus statement by the Spine Trauma Study Group. Medical records were reviewed to determine associated pelvic and non-pelvic fractures, bladder and bowel injuries, nerve injuries, and type of surgical intervention. Twenty-one patients had SPD, of whom 13 were men and eight were women. Mean age was 41.8 years (range 18.8 to 87.7). Five fractures (24 %) were U-shaped, six (29 %) H-shaped, four (19 %) Y-shaped, and six (29 %) burst. Nine patients (43 %) had central canal narrowing, and 19 (90 %) had neural foramina narrowing. Eleven patients (52 %) had kyphotic angulation between major fracture fragments, and seven patients (33 %) had either anterior (24 %) or posterior (10 %) displacement of the proximal fracture fragment. Fourteen patients (67 %) had associated pelvic fractures, and 20 (95 %) had associated non-pelvic fractures. Two patients (10 %) had associated urethral injuries, and one (5 %) had an associated colon injury. Seven patients (33 %) had associated nerve injuries. Six patients (29 %) had surgical fixation while 15 (71 %) were

PATIENT-SPECIFIC FINITE ELEMENT ANALYSIS OF CHRONIC CONTACT STRESS EXPOSURE AFTER INTRA-ARTICULAR FRACTURE OF THE TIBIAL PLAFOND

PubMed Central

Li, Wendy; Anderson, Donald D.; Goldsworthy, Jane K.; Marsh, J. Lawrence; Brown, Thomas D.

2008-01-01

SUMMARY The role of altered contact mechanics in the pathogenesis of post-traumatic osteoarthritis (PTOA) following intra-articular fracture remains poorly understood. One proposed etiology is that residual incongruities lead to altered joint contact stresses that, over time, predispose to PTOA. Prevailing joint contact stresses following surgical fracture reduction were quantified in this study using patient-specific contact finite element (FE) analysis. FE models were created for 11 ankle pairs from tibial plafond fracture patients. Both (reduced) fractured ankles and their intact contralaterals were modeled. A sequence of 13 loading instances was used to simulate the stance phase of gait. Contact stresses were summed across loadings in the simulation, weighted by resident time in the gait cycle. This chronic exposure measure, a metric of degeneration propensity, was then compared between intact and fractured ankle pairs. Intact ankles had lower peak contact stress exposures that were more uniform, and centrally located. The series-average peak contact stress elevation for fractured ankles was 38% (p=0.0015; peak elevation was 82%). Fractured ankles had less area with low contact stress exposure than intacts, and a greater area with high exposure. Chronic contact stress overexposures (stresses exceeding a damage threshold) ranged from near zero to a high of 18 times the matched intact value. The patient-specific FE models utilized in this study represent substantial progress towards elucidating the relationship between altered contact stresses and the outcome of patients treated for intra-articular fractures. PMID:18404662

Effective-stress-law behavior of Austin chalk rocks for deformation and fracture conductivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warpinski, N.R.; Teufel, L.W.

Austin chalk core has been tested to determine the effective law for deformation of the matrix material and the stress-sensitive conductivity of the natural fractures. For deformation behavior, two samples provided data on the variations of the poroelastic parameter, {alpha}, for Austin chalk, giving values around 0.4. The effective-stress-law behavior of a Saratoga limestone sample was also measured for the purpose of obtaining a comparison with a somewhat more porous carbonate rock. {alpha} for this rock was found to be near 0.9. The low {alpha} for the Austin chalk suggests that stresses in the reservoir, or around the wellbore, willmore » not change much with changes in pore pressure, as the contribution of the fluid pressure is small. Three natural fractures from the Austin chalk were tested, but two of the fractures were very tight and probably do not contribute much to production. The third sample was highly conductive and showed some stress sensitivity with a factor of three reduction in conductivity over a net stress increase of 3000 psi. Natural fractures also showed a propensity for permanent damage when net stressed exceeded about 3000 psi. This damage was irreversible and significantly affected conductivity. {alpha} was difficult to determine and most tests were inconclusive, although the results from one sample suggested that {alpha} was near unity.« less

Crack-jump mechanism of microvein formation and its implications for stress cyclicity during extension fracturing

NASA Astrophysics Data System (ADS)

Caputo, Riccardo; Hancock, Paul L.

1998-11-01

It is well accepted and documented that faulting is produced by the cyclic behaviour of a stress field. Some extension fractures, such as veins characterised by the crack-seal mechanism, have also been presumed to result from repeated stress cycles. In the present note, some commonly observed field phenomena and relationships such as hackle marks and vein and joint spacing, are employed to argue that a stress field can also display cyclic behaviour during extensional fracturing. Indeed, the requirement of critical stress conditions for the occurrence of extensional failure events does not accord with the presence of contemporaneously open nearby parallel fractures. Therefore, because after each fracture event there is stress release within the surrounding volume of rock, high density sets of parallel extensional fractures also strongly support the idea that rocks undergo stress cyclicity during jointing and veining. A comparison with seismological data from earthquakes with dipole mechanical solutions, confirms that this process presently occurs at depth in the Earth crust. Furthermore, in order to explain dense sets of hair-like closely spaced microveins, a crack-jump mechanism is introduced here as an alternative to the crack-seal mechanism. We also propose that as a consequence of medium-scale stress cyclicity during brittle deformation, the re-fracturing of a rock mass occurs in either one or the other of these two possible ways depending on the ratio between the elastic parameters of the sealing material and those of the host rock. The crack-jump mechanism occurs when the former is stronger.

Stress corrosion-controlled rates of mode I fracture propagation in calcareous bedrock

NASA Astrophysics Data System (ADS)

Voigtlaender, Anne; Leith, Kerry; Krautblatter, Michael

2014-05-01

Surface bedrock on natural rock slopes is subject to constant and cyclic environmental stresses (wind, water, wave, ice, seismic or gravitational). Studies indicate that these stresses range up to several hundred kPa, generally too low to cause macroscopic changes in intact rock, although clear evidence of fracture generation, crack propagation and weathering of bedrock illustrates the effect of environmental stresses at the Earth's surface. We suggest that material degradation and its extent, is likely to be controlled by the rate of stress corrosion cracking (SCC). Stress corrosion is a fluid-material reaction, where fluids preferentially react with strained atomic bonds at the tip of developing fractures. Stress corrosion in ferrous and siliceous materials is often accepted as the fracture propagation and degradation rate-controlling process where materials are subject to stresses and fluids. Although evidence for chemical weathering in propagating bedrock fractures is clear in natural environments, the physical system and quantification of stress corrosion in natural rocks is yet to be addressed. Here, we present preliminary data on the relationship between stresses at levels commonly present on natural rock slopes, and material damage resulting from stress corrosion under constant or cyclic tensile loading. We undertake single notch three-point bending tests (SNBT) on fresh calcareous bedrock specimens (1100x100x100mm) over a two-month period. Two beams containing an artificial notch are stressed to 75% of their ultimate strength, and a constant supply of weak acid is applied at the notch tip to enhance chemical reactions. A third, unloaded, beam is also exposed to weak acid in order to elucidate the contribution of stress corrosion cracking to the material degradation. Stresses at the tip of propagating cracks affect the kinetics of the chemical reaction in the specimen exposed to both loading and corrosion, leading to an increase in degradation, and greater

Presacral abscess as a rare complication of sacral nerve stimulator implantation.

PubMed

Gumber, A; Ayyar, S; Varia, H; Pettit, S

2017-03-01

A 50-year-old man with intractable anal pain attributed to proctalgia fugax underwent insertion of a sacral nerve stimulator via the right S3 vertebral foramen for pain control with good symptomatic relief. Thirteen months later, he presented with signs of sepsis. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a large presacral abscess. MRI demonstrated increased enhancement along the pathway of the stimulator electrode, indicating that the abscess was caused by infection introduced at the time of sacral nerve stimulator placement. The patient was treated with broad spectrum antibiotics, and the sacral nerve stimulator and electrode were removed. Attempts were made to drain the abscess transrectally using minimally invasive techniques but these were unsuccessful and CT guided transperineal drainage was then performed. Despite this, the presacral abscess progressed, developing enlarging gas locules and extending to the pelvic brim to involve the aortic bifurcation, causing hydronephrosis and radiological signs of impending sacral osteomyelitis. MRI showed communication between the rectum and abscess resulting from transrectal drainage. In view of the progressive presacral sepsis, a laparotomy was performed with drainage of the abscess, closure of the upper rectum and formation of a defunctioning end sigmoid colostomy. Following this, the presacral infection resolved. Presacral abscess formation secondary to an infected sacral nerve stimulator electrode has not been reported previously. Our experience suggests that in a similar situation, the optimal management is to perform laparotomy with drainage of the presacral abscess together with simultaneous removal of the sacral nerve stimulator and electrode.

Presacral abscess as a rare complication of sacral nerve stimulator implantation

PubMed Central

Gumber, A; Ayyar, S; Varia, H

2017-01-01

A 50-year-old man with intractable anal pain attributed to proctalgia fugax underwent insertion of a sacral nerve stimulator via the right S3 vertebral foramen for pain control with good symptomatic relief. Thirteen months later, he presented with signs of sepsis. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a large presacral abscess. MRI demonstrated increased enhancement along the pathway of the stimulator electrode, indicating that the abscess was caused by infection introduced at the time of sacral nerve stimulator placement. The patient was treated with broad spectrum antibiotics, and the sacral nerve stimulator and electrode were removed. Attempts were made to drain the abscess transrectally using minimally invasive techniques but these were unsuccessful and CT guided transperineal drainage was then performed. Despite this, the presacral abscess progressed, developing enlarging gas locules and extending to the pelvic brim to involve the aortic bifurcation, causing hydronephrosis and radiological signs of impending sacral osteomyelitis. MRI showed communication between the rectum and abscess resulting from transrectal drainage. In view of the progressive presacral sepsis, a laparotomy was performed with drainage of the abscess, closure of the upper rectum and formation of a defunctioning end sigmoid colostomy. Following this, the presacral infection resolved. Presacral abscess formation secondary to an infected sacral nerve stimulator electrode has not been reported previously. Our experience suggests that in a similar situation, the optimal management is to perform laparotomy with drainage of the presacral abscess together with simultaneous removal of the sacral nerve stimulator and electrode. PMID:28071947

The impact of different aperture distribution models and critical stress criteria on equivalent permeability in fractured rocks

NASA Astrophysics Data System (ADS)

Bisdom, Kevin; Bertotti, Giovanni; Nick, Hamidreza M.

2016-05-01

Predicting equivalent permeability in fractured reservoirs requires an understanding of the fracture network geometry and apertures. There are different methods for defining aperture, based on outcrop observations (power law scaling), fundamental mechanics (sublinear length-aperture scaling), and experiments (Barton-Bandis conductive shearing). Each method predicts heterogeneous apertures, even along single fractures (i.e., intrafracture variations), but most fractured reservoir models imply constant apertures for single fractures. We compare the relative differences in aperture and permeability predicted by three aperture methods, where permeability is modeled in explicit fracture networks with coupled fracture-matrix flow. Aperture varies along single fractures, and geomechanical relations are used to identify which fractures are critically stressed. The aperture models are applied to real-world large-scale fracture networks. (Sub)linear length scaling predicts the largest average aperture and equivalent permeability. Barton-Bandis aperture is smaller, predicting on average a sixfold increase compared to matrix permeability. Application of critical stress criteria results in a decrease in the fraction of open fractures. For the applied stress conditions, Coulomb predicts that 50% of the network is critically stressed, compared to 80% for Barton-Bandis peak shear. The impact of the fracture network on equivalent permeability depends on the matrix hydraulic properties, as in a low-permeable matrix, intrafracture connectivity, i.e., the opening along a single fracture, controls equivalent permeability, whereas for a more permeable matrix, absolute apertures have a larger impact. Quantification of fracture flow regimes using only the ratio of fracture versus matrix permeability is insufficient, as these regimes also depend on aperture variations within fractures.

Finding sacral: Developmental evolution of the axial skeleton of odontocetes (Cetacea).

PubMed

Buchholtz, Emily A; Gee, Jessica K

2017-07-01

Axial morphology was dramatically transformed during the transition from terrestrial to aquatic environments by archaeocete cetaceans, and again during the subsequent odontocete radiation. Here, we reconstruct the sequence of developmental events that underlie these phenotypic transitions. Archaeocete innovations include the loss of primaxial/abaxial interaction at the sacral/pelvic articulation and the modular dissociation of the fluke from the remainder of the tail. Odontocetes subsequently integrated lumbar, sacral, and anterior caudal vertebrae into a single torso module, and underwent multiple series-specific changes in vertebral count. The conservation of regional proportions despite regional fluctuations in count strongly argues that rates of somitogenesis can vary along the column and that segmentation was dissociated from regionalization during odontocete evolution. Conserved regional proportions also allow the prediction of the location and count of sacral homologs within the torso module. These predictions are tested with the analysis of comparative pudendal nerve root location and geometric morphometrics. We conclude that the proportion of the column represented by the sacral series has been conserved, and that its vertebrae have changed in count and relative centrum length in parallel with other torso vertebrae. Although the sacral series of odontocetes is de-differentiated, it is not de-regionalized. © 2017 Wiley Periodicals, Inc.

Cost of dressings for prevention of sacral pressure ulcers.

PubMed

Inoue, Kelly Cristina; Matsuda, Laura Misue

2016-01-01

to identify costs of dressings to prevent sacral pressure ulcers in an adult intensive care unit in Paraná, Brazil. secondary analysis study with 25 patients admitted between October 2013 and March 2014, using transparent polyurethane film (n=15) or hydrocolloid dressing (n=10) on the sacral region. The cost of each intervention was based on the unit amount used in each type of dressing, and its purchase price (transparent film = R$15.80, hydrocolloid dressing = R$68.00). the mean cost/patient was R$23.17 for use of transparent film and R$190.40 for use of hydrocolloid dressing. The main reason for changing the dressing was detachment. the transparent film was the most economically advantageous alternative to prevent sacral pressure ulcers in critical care patients. However, additional studies should be carried out including assessment of the effectiveness of both dressings.

Permeability, Fracture Clusters, and Stress State:Implications for Mine-based Studies of EcoHydrology

NASA Astrophysics Data System (ADS)

Earnest, E. J.; Boutt, D. F.; Murdoch, L.; Hisz, D. B.; Ebenhack, J.; Kieft, T. L.; Onstott, T. C.; Wang, H. F.

2011-12-01

Mine-based ecohydrology studies provide unique access to deep flow systems at multiple crustal depths. Mass and energy transfer in such deep flow systems is typically dominated by localized flow through discrete features such as fractures and faults, of which only a small percentage contribute to both local and regional flow systems. Predicting which fractures are contributing to flow and transport in these networks has proven extremely difficult. Researchers working at deeper crustal levels (Barton et al., 1995) have successfully predicted fracture network permeability using relationships between fracture aperture (i.e. transmissivity) and in-situ stress. Observations suggest that compared to porous media, fractured rocks have flow systems that operate across large spatial scales and may contain clusters that are hydraulically isolated. . This point is important as these flow systems can house fluids and microbes in isolated clusters and are minimally impacted by the presence of a mine. One example of this is the the former Homestake gold mine in the northern Black Hills, South Dakota, which is being considered as a location for an underground science laboratory. Mine workings cover several km2 in plan and extend to a depth 2.4 km. The area is dominantly Proterozoic metamorphic rocks, forming regional-scale folds with plunge axes oriented ~40o to the SSE. Prior analysis of the hydrogeology of the area indicates that permeability is strongly dependent on effective stress; an increase in permeability with decreasing depth appears to be an important factor controlling the development of a shallow ground water flow systems. In this contribution we examine a set of factors contributing to permeability distribution at the site with a specific focus on: 1) refining permeability-depth models for fractured rock to include the influence of both normal and shear fracture deformation on permeability-depth trends, 2) promote the development and testing of a stress

Factors associated with recurrent fifth metatarsal stress fracture.

PubMed

Lee, Kyung-tai; Park, Young-uk; Jegal, Hyuk; Kim, Ki-chun; Young, Ki-won; Kim, Jin-su

2013-12-01

Many surgeons agree that fifth metatarsal stress fractures have a tendency toward delayed union, nonunion, and possibly refracture. Difficulty healing seems to be correlated with fracture classification. However, refracture sometimes occurs after low-grade fracture, even long after apparent resolution. The records of 168 consecutive cases of fifth metatarsal stress fracture (163 patients) treated by modified tension band wiring from March 2002 to June 2011 were evaluated retrospectively. Mean length of follow-up was 23.6 months (range, 10-112 months). Forty-nine cases classified as Torg III were bone grafted initially also. All enrolled patients were elite athletes. Eleven patients experienced nonunion and 18 refracture. The 11 nonunion cases were bone grafted. The 157 patients (excluding nonunion cases) were allocated to either a refracture group or a union group. Clinical features, such as age, weight, fracture classification, time to union, and reinjury history, were compared. Radiological parameters representing cavus deformity and fifth metatarsal head protrusion were compared to evaluate the influence of structural abnormalities. Mean group weights were significantly different (P = .041), but mean ages (P = .879), fracture grades (P = .216, P = .962), and time from surgery to rehabilitation (P = .539) were similar. No significant intergroup differences were found for talocalcaneal (TC) angle (P = .470), calcaneal pitch (CP) angle (P = .847), or talo-first metatarsal (T-MT1) angle (P = .407) on lateral radiographs; for fifth metatarsal lateral deviation (MT5-LD) angle (P = .623) on anteroposterior (AP) radiographs; or for MT5-LD angle (P = .065) on the 30-degree medial oblique radiographs. However, the mean fourth-fifth intermetatarsal (IMA4-5) angle on AP radiographs was significantly greater in the refracture group, and for Torg II cases, mean weight (P = .042), IMA4-5 angle on AP radiographs (P = .014), and MT5-LD angle (P = .043) on 30-degree medial

Tension Band Plating for Chronic Anterior Tibial Stress Fractures in High-Performance Athletes.

PubMed

Zbeda, Robert M; Sculco, Peter K; Urch, Ekaterina Y; Lazaro, Lionel E; Borens, Olivier; Williams, Riley J; Lorich, Dean G; Wellman, David S; Helfet, David L

2015-07-01

Anterior tibial stress fractures are associated with high rates of delayed union and nonunion, which can be particularly devastating to a professional athlete who requires rapid return to competition. Current surgical treatment strategies include intramedullary nailing, which has satisfactory rates of fracture union but an associated risk of anterior knee pain. Anterior tension band plating is a biomechanically sound alternative treatment for these fractures. Tension band plating of chronic anterior tibial stress fractures leads to rapid healing and return to physical activity and avoids the anterior knee pain associated with intramedullary nailing. Case series; Level of evidence, 4. Between 2001 and 2013, there were 13 chronic anterior tibial stress fractures in 12 professional or collegiate athletes who underwent tension band plating after failing nonoperative management. Patient charts were retrospectively reviewed for demographics, injury history, and surgical details. Radiographs were used to assess time to osseous union. Follow-up notes and phone interviews were used to determine follow-up time, return to training time, and whether the patient was able to return to competition. Cases included 13 stress fractures in 12 patients (9 females, 3 males). Five patients were track-and-field athletes, 4 patients played basketball, 2 patients played volleyball, and 1 was a ballet dancer. Five patients were Division I collegiate athletes and 7 were professional or Olympic athletes. Average age at time of surgery was 23.6 years (range, 20-32 years). Osseous union occurred on average at 9.6 weeks (range, 5.3-16.9 weeks) after surgery. Patients returned to training on average at 11.1 weeks (range, 5.7-20 weeks). Ninety-two percent (12/13) eventually returned to preinjury competition levels. Thirty-eight percent (5/13) underwent removal of hardware for plate prominence. There was no incidence of infection or nonunion. Anterior tension band plating for chronic tibial stress

Excess Stress Fractures, Musculoskeletal Injuries, and Health Care Utilization Among Unfit and Overweight Female Army Trainees.

PubMed

Krauss, Margot R; Garvin, Nadia U; Boivin, Michael R; Cowan, David N

2017-02-01

Musculoskeletal injuries are prevalent among military trainees and certain occupations. Fitness and body mass index (BMI) have been associated with musculoskeletal conditions, including stress fractures. The incidence of, and excess health care utilization for, stress fracture and non-stress fracture overuse musculoskeletal injuries during the first 6 months of service is higher among unfit female recruits. Those who exceeded body fat limits are at a greater risk of incident stress fractures, injuries, or health care utilization compared with weight-qualified recruits. Cohort study; Level of evidence, 3. All applicants to the United States Army were required to take a preaccession fitness test during the study period (February 2005-September 2006). The test included a 5-minute step test scored as pass or fail. BMI was recorded at application. There were 2 distinct comparisons made in this study: (1) between weight-qualified physically fit and unfit women and (2) between weight-qualified physically fit women and those who exceeded body fat limits. We compared the incidence of, and excess health care utilization for, musculoskeletal injuries, including stress fractures and physical therapy visits, during the first 183 days of military service. Among the weight-qualified women, unfit participants had a higher non-stress fracture injury incidence and related excess health care utilization rate compared with fit women, with rate ratios of 1.32 (95% CI, 1.14-1.53) and 1.18 (95% CI, 1.10-1.27), respectively. Among fit women, compared with the weight-qualified participants, those exceeding body fat limits had higher rate ratios for non-stress fracture injury incidence and related excess health care utilization of 1.27 (95% CI, 1.07-1.50) and 1.20 (95% CI, 1.11-1.31), respectively. Weight-qualified women who were unfit had a higher incidence of stress fractures and related excess health care utilization compared with fit women, with rate ratios of 1.62 (95% CI, 1

Serum 25-Hydroxyvitamin D Levels and Stress Fractures in Military Personnel: A Systematic Review and Meta-analysis.

PubMed

Dao, Dyda; Sodhi, Sukhmani; Tabasinejad, Rasam; Peterson, Devin; Ayeni, Olufemi R; Bhandari, Mohit; Farrokhyar, Forough

2015-08-01

Low serum 25-hydroxyvitamin D (25(OH)D) levels have been associated with stress fractures in various physically active populations such as the military. To examine the association between serum 25(OH)D levels and stress fractures in the military. Systematic review and meta-analysis. Relevant studies were identified through searching multiple databases and manually screening reference lists. Two reviewers independently selected the included studies by applying the eligibility criteria to the title, abstract, and/or full text of the articles yielded in the search. Two reviewers also independently conducted the methodological quality assessment and data extraction. A random-effects model was used to calculate the mean difference (MD) with 95% CI in serum 25(OH)D levels between stress fracture cases and controls. Nine observational studies on lower extremity stress fractures were eligible, and 1 was excluded due to inadequate data. A total of 2634 military personnel (age, 18-30 years; 44% male) with 761 cases (16% male) and 1873 controls (61% male) from 8 studies were included in the analysis. Three of the 8 studies measured serum 25(OH)D levels at the time of stress fracture diagnosis, and the 5 remaining studies measured serum 25(OH)D levels at the time of entry into basic training. The mean serum 25(OH)D level was lower in stress fracture cases than in controls at the time of entry into basic training (MD, -2.63 ng/mL; 95% CI, -5.80 to 0.54; P = .10; I(2) = 65%) and at the time of stress fracture diagnosis (MD, -2.26 ng/mL; 95% CI, -3.89 to -0.63; P = .007; I(2) = 42%). Despite the inherent limitations of the included studies, the study results suggest some association between low serum 25(OH)D levels and lower extremity stress fractures in military personnel. Given the rigorous training of military personnel, implementing strategies to ensure sufficient 25(OH)D levels may be beneficial for reducing the risk of stress fractures. © 2014 The Author(s).

Short-term effects of teriparatide versus placebo on bone biomarkers, structure, and fracture healing in women with lower-extremity stress fractures: A pilot study.

PubMed

Almirol, Ellen A; Chi, Lisa Y; Khurana, Bharti; Hurwitz, Shelley; Bluman, Eric M; Chiodo, Christopher; Matzkin, Elizabeth; Baima, Jennifer; LeBoff, Meryl S

2016-09-01

In this pilot, placebo-controlled study, we evaluated whether brief administration of teriparatide (TPTD) in premenopausal women with lower-extremity stress fractures would increase markers of bone formation in advance of bone resorption, improve bone structure, and hasten fracture healing according to magnetic resonance imaging (MRI). Premenopausal women with acute lower-extremity stress fractures were randomized to injection of TPTD 20-µg subcutaneous (s.c.) (n = 6) or placebo s.c. (n = 7) for 8 weeks. Biomarkers for bone formation N-terminal propeptide of type I procollagen (P1NP) and osteocalcin (OC) and resorption collagen type-1 cross-linked C-telopeptide (CTX) and collagen type 1 cross-linked N-telopeptide (NTX) were measured at baseline, 4 and 8 weeks. The area between the percent change of P1NP and CTX over study duration is defined as the anabolic window. To assess structural changes, peripheral quantitative computed topography (pQCT) was measured at baseline, 8 and 12 weeks at the unaffected tibia and distal radius. The MRI of the affected bone assessed stress fracture healing at baseline and 8 weeks. After 8 weeks of treatment, bone biomarkers P1NP and OC increased more in the TPTD- versus placebo-treated group (both p ≤ 0.01), resulting in a marked anabolic window (p ≤ 0.05). Results from pQCT demonstrated that TPTD-treated women showed a larger cortical area and thickness compared to placebo at the weight bearing tibial site, while placebo-treated women had a greater total tibia and cortical density. No changes at the radial sites were observed between groups. According to MRI, 83.3% of the TPTD- and 57.1% of the placebo-treated group had improved or healed stress fractures (p = 0.18). In this randomized, pilot study, brief administration of TPTD showed anabolic effects that TPTD may help hasten fracture healing in premenopausal women with lower-extremity stress fractures. Larger prospective studies are warranted to determine

[Four cases of urinary dysfunction associated with sacral herpes zoster].

PubMed

Matsuo, Tomohiro; Oba, Kojiro; Miyata, Yasuyoshi; Igawa, Tsukasa; Sakai, Hideki

2014-02-01

Herpes zoster is caused by the infection of Varicella-Zoster virus. The anatomical distribution of herpes zoster in the sacral area is only 6. 9%1). Moreover, the onset rate of herpes zoster with urinary dysfunction is 0.6%1). The lesion sites of herpes zoster which cause urinary dysfunction are almost lumber and sacral areas. We describe four cases of sacral herpes zoster with urinary dysfunction in this report. All patients were elderly people (66-84 years old), and all patients were administered anti-virus drugs and alpha 1-adrenergic receptor blockers. Because of urinary retention, three patients have performed clean intermittent self-catheterization (CIC) for several weeks. As the lesions of herpes zoster healed, each patient recovered from urinary dysfunction.

The Epidemiology of Stress Fractures in Collegiate Student-Athletes, 2004-2005 Through 2013-2014 Academic Years.

PubMed

Rizzone, Katherine H; Ackerman, Kathryn E; Roos, Karen G; Dompier, Thomas P; Kerr, Zachary Y

2017-10-01

  Stress fractures are injuries caused by cumulative, repetitive stress that leads to abnormal bone remodeling. Specific populations, including female athletes and endurance athletes, are at higher risk than the general athletic population. Whereas more than 460 000 individuals participate in collegiate athletics in the United States, no large study has been conducted to determine the incidence of stress fractures in collegiate athletes.   To assess the incidence of stress fractures in National Collegiate Athletic Association (NCAA) athletes and investigate rates and patterns overall and by sport.   Descriptive epidemiology study.   National Collegiate Athletic Association institutions.   National Collegiate Athletic Association athletes.   Data were analyzed from the NCAA Injury Surveillance Program for the academic years 2004-2005 through 2013-2014. We calculated rates and rate ratios (RRs) with 95% confidence intervals (CIs).   A total of 671 stress fractures were reported over 11 778 145 athlete-exposures (AEs) for an overall injury rate of 5.70 per 100 000 AEs. The sports with the highest rates of stress fractures were women's cross-country ( 28.59/100  000 AEs), women's gymnastics ( 25.58/100  000 AEs), and women's outdoor track ( 22.26/100  000 AEs). Among sex-comparable sports (baseball/softball, basketball, cross-country, ice hockey, lacrosse, soccer, swimming and diving, tennis, indoor track, and outdoor track), stress fracture rates were higher in women (9.13/100 000 AEs) than in men (4.44/100 000 AEs; RR = 2.06; 95% CI = 1.71, 2.47). Overall, stress fracture rates for these NCAA athletes were higher in the preseason (7.30/100 000 AEs) than in the regular season (5.12/100 000 AEs; RR = 1.43; 95% CI = 1.22, 1.67). The metatarsals (n = 254, 37.9%), tibia (n = 147, 21.9%), and lower back/lumbar spine/pelvis (n = 81, 12.1%) were the most common locations of injury. Overall, 21.5% (n = 144) of stress fractures were

Induced stress changes and associated fracture development as a result of deglaciation on the Zugspitzplatt, SE Germany

NASA Astrophysics Data System (ADS)

Leith, Kerry; Kupp, Jan; Geisenhof, Benedikt; Krautblatter, Michael

2015-04-01

Bedrock stresses in alpine regions result from the combined effects of exhumation, tectonics, topography, inelastic strain (e.g. fault displacement and fracture formation), and external loading. Gravitational loading by glacial ice can significantly affect near-surface stress magnitudes, although the nature of this effect and it's impact on stress distributions and bedrock fracturing is strongly dependent on the stress history of the bedrock landscape. We assess the effects of recent (post-Little Ice Age , ~1850 AD) and future deglaciation on bedrock stresses in the region of the Zugspitzplatt, a glaciated plateau surrounded by 1500 m high bedrock walls in SE Germany. We address this by undertaking a 2-D elasto-plastic finite element method analysis of stress changes and fracture propagation due to repeated glacial - interglacial cycles. Our model is initialised with upper crustal stresses in equilibrium with bedrock strength and regional tectonics, and we then simulate two cycles of major Pleistocene glaciation and deglaciation in order to dissipate stress concentrations and incorporate path-dependent effects of glacial loading on the landscape. We then simulate a final glacial cycle, and remove 1 m of bedrock to approximate glacial erosion across the topography. Finally, ice levels are reduced in accordance with known late-glacial and recent ice retreat, allowing us to compare relative stress changes and predicted patterns of fracture propagation to observed fracture distributions on the Zugspitzplatt. Model results compare favourably to observed fracture patterns, and indicate the plateau is likely to be undergoing N-S extension as a result of deglaciation, with a strong reduction of horizontal stress magnitudes beneath the present-day Schneeferner glacier. As each glacial cycle has a similar effect on the plateau, it is likely that surficial stresses are slightly tensile, and each cycle of deglaciation produces additional sub-vertical tensile fractures, which

Effect of Stress Triaxiality on the Flow and Fracture of Mg Alloy AZ31

NASA Astrophysics Data System (ADS)

Kondori, Babak; Benzerga, A. Amine

2014-07-01

The microscopic damage mechanisms operating in a hot-rolled magnesium alloy AZ31B are investigated under both uniaxial and controlled triaxial loadings. Their connection to macroscopic fracture strains and fracture mode (normal vs shear) is elucidated using postmortem fractography, interrupted tests, and microscopic analysis. The fracture locus (strain-to-failure vs stress triaxiality) exhibits a maximum at moderate triaxiality, and the strain-to-failure is found to be greater in notched specimens than in initially smooth ones. A transition from twinning-induced fracture under uniaxial loading to microvoid coalescence fracture under triaxial loading is evidenced. It is argued that this transition accounts in part for the observed greater ductility in notched bars. The evolution of plastic anisotropy with stress triaxiality is also investigated. It is inferred that anisotropic plasticity at a macroscopic scale suffices to account for the observed transition in the fracture mode from flat (triaxial loading) to shear-like (uniaxial loading). Damage is found to initiate at second-phase particles and deformation twins. Fracture surfaces of broken specimens exhibit granular morphology, coarse splits, twin-sized crack traces, as well as shallow and deep dimples, in proportions that depend on the overall stress triaxiality and fracture mode. An important finding is that AZ31B has a greater tolerance to ductile damage accumulation than has been believed thus far, based on the fracture behavior in uniaxial specimens. Another finding, common to both tension and compression, is the increase in volumetric strain, the microscopic origins of which remain to be elucidated.

Use of non-fault fractures in stress tensor reconstruction using the Mohr Circle with the Win-tensor program

NASA Astrophysics Data System (ADS)

Delvaux, Damien

2016-04-01

Paleostress inversion of geological fault-slip data is usually done using the directional part of the applied stress tensor on a slip plane and comparing it with the observed slip lines. However, this method do not fully exploit the brittle data sets as those are composed of shear and tension fractures, in addition to faults. Brittle deformation can be decomposed in two steps. An initial fracture/failure in previously intact rock generate extension/tensile fractures or shear fractures, both without visible opening or displacement. This first step may or not be followed by fracture opening to form tension joints, frictional shearing to form shear faults, or a combination of opening and shearing which produces hybrid fractures. Fractured rock outcrop contain information of the stress conditions that acted during both brittle deformation steps. The purpose here is to investigate how the fracture pattern generated during the initial fracture/failure step might be used in paleostress reconstruction. Each fracture is represented on the Mohr Circle by its resolved normal and shear stress magnitudes. We consider the typical domains on the Mohr circle where the different types de fractures nucleate (tension, hybrid, shear and compression fractures), as well the domain which contain reactivated fractures (faults reactivating an initial fracture plane). In function of the fracture type defined in the field, a "distance" is computed on the Mohr circle between each point and its expected corresponding nucleation/reactivation domain. This "Mohr Distance" is then used as function to minimize during the inversion. We implemented this new function in the Win-Tensor program, and tested it with natural and synthetic data sets from different stress regimes. It can be used alone using only the Mohr Distance on each plane (function F10), or combined with the angular misfit between observed striae and resolved shear directions (composite function F11). When used alone (F10), only the 3

Transcutaneous sacral neurostimulation for irritative voiding dysfunction.

PubMed

Walsh, I K; Johnston, R S; Keane, P F

1999-01-01

Patients with irritative voiding dysfunction are often unresponsive to standard clinical treatment. We evaluated the response of such individuals to transcutaneous electrical stimulation of the third sacral nerve. 32 patients with refractory irritative voiding dysfunction (31 female and 1 male; mean age 47 years) were recruited to the study. Ambulatory transcutaneous electrical neurostimulation was applied bilaterally to the third sacral dermatomes for 1 week. Symptoms of frequency, nocturia, urgency, and bladder pain were scored by each patient throughout and up to 6 months following treatment. The mean daytime frequency was reduced from 11.3 to 7.96 (p = 0.01). Nocturia episodes were reduced from a mean of 2.6 to 1.8 (p = 0.01). Urgency and bladder pain mean symptom scores were reduced from 5.97 to 4.89 and from 1.48 to 0.64, respectively. After stopping therapy, symptoms returned to pretreatment levels within 2 weeks in 40% of the patients and within 6 months in 100%. Three patients who continued with neurostimulation remained satisfied with this treatment modality at 6 months. Transcutaneous third sacral nerve stimulation may be an effective and noninvasive ambulatory technique for the treatment of patients with refractory irritative voiding dysfunction. Following an initial response, patients may successfully apply this treatment themselves to ensure long-term relief.

Characterization and modeling of the stress and pore-fluid dependent acoustic properties of fractured porous rocks

NASA Astrophysics Data System (ADS)

Almrabat, Abdulhadi M.

The thesis presents the results of a study of the characterization and modeling of the stress and pore-fluid dependent acoustic properties of fractured porous rocks. A new laboratory High Pressure and High Temperature (HPHT) triaxial testing system was developed to characterize the seismic properties of sandstone under different levels of effective stress confinement and changes in pore-fluid composition. An intact and fractured of Berea sandstones core samples were used in the experimental studies. The laboratory test results were used to develop analytical models for stress-level and pore-fluid dependent seismic velocity of sandstones. Models for stress-dependent P and S-wave seismic velocities of sandstone were then developed based on the assumption that stress-dependencies come from the nonlinear elastic response of micro-fractures contained in the sample under normal and shear loading. The contact shear stiffness was assumed to increase linearly with the normal stress across a micro-fracture, while the contact normal stiffness was assumed to vary as a power law with the micro-fracture normal stress. Both nonlinear fracture normal and shear contact models were validated by experimental data available in the literature. To test the dependency of seismic velocity of sandstone on changes in pore-fluid composition, another series of tests were conducted where P and S-wave velocities were monitored during injection of supercritical CO 2 in samples of Berea sandstone initially saturated with saline water and under constant confining stress. Changes in seismic wave velocity were measured at different levels of supercritical CO2 saturation as the initial saline water as pore-fluid was displaced by supercritical CO 2. It was found that the P- iv wave velocity significantly decreased while the S-wave velocity remained almost constant as the sample supercritical CO2 saturation increased. The dependency of the seismic velocity on changes on pore fluid composition during

Acute changes in foot strike pattern and cadence affect running parameters associated with tibial stress fractures.

PubMed

Yong, Jennifer R; Silder, Amy; Montgomery, Kate L; Fredericson, Michael; Delp, Scott L

2018-05-18

Tibial stress fractures are a common and debilitating injury that occur in distance runners. Runners may be able to decrease tibial stress fracture risk by adopting a running pattern that reduces biomechanical parameters associated with a history of tibial stress fracture. The purpose of this study was to test the hypothesis that converting to a forefoot striking pattern or increasing cadence without focusing on changing foot strike type would reduce injury risk parameters in recreational runners. Running kinematics, ground reaction forces and tibial accelerations were recorded from seventeen healthy, habitual rearfoot striking runners while running in their natural running pattern and after two acute retraining conditions: (1) converting to forefoot striking without focusing on cadence and (2) increasing cadence without focusing on foot strike. We found that converting to forefoot striking decreased two risk factors for tibial stress fracture: average and peak loading rates. Increasing cadence decreased one risk factor: peak hip adduction angle. Our results demonstrate that acute adaptation to forefoot striking reduces different injury risk parameters than acute adaptation to increased cadence and suggest that both modifications may reduce the risk of tibial stress fractures. Copyright © 2018 Elsevier Ltd. All rights reserved.

Bilateral periprosthetic tibial stress fracture after total knee arthroplasty: A case report.

PubMed

Ozdemir, Guzelali; Azboy, Ibrahim; Yilmaz, Baris

2016-01-01

Periprosthetic fractures around the knee after total knee arthroplasty can be seen in the femur, tibia and patella. The tibial fractures are rare cases. Our case with bilateral tibial stress fracture developed after total knee arthroplasty (TKA) is the first of its kind in the literature. 75-year-old male patient with bilateral knee osteoarthritis had not benefited from conservative treatment methods previously applied. Left TKA was applied. In the second month postoperatively, periprosthetic tibial fracture was identified and osteosynthesis was implemented with locked tibia proximal plate-screw. Bone union in 12 weeks was observed in his follow-ups. After 15 months of his first operation, TKA was applied to the right knee. Postoperatively in the second month, as in the first operation, periprosthetic tibial fracture was detected. Osteosynthesis with locking plate-screw was applied and union in 12 weeks was observed in his follow-up. He was seen mobilized independently and without support in the last control of the case made in the 24th month after the second operation. The number of TKA applications is expected to increase in the future. The incidence of periprosthetic fractures should also be expected to increase in these cases. Periprosthetic tibial fractures after TKA are rarely seen. The treatment of periprosthetic fractures around the knee after TKA can be difficult. In the case of persistent pain in the upper end of the tibia after the surgery, stress fracture should be considered. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Preliminary results of sacral transcutaneous electrical nerve stimulation for fecal incontinence.

PubMed

Leung, Edmund; Francombe, James

2013-03-01

Fecal incontinence is a common debilitating condition. The aim of this study is to investigate the feasibility of sacral transcutaneous electrical nerve stimulation as an alternative treatment modality for fecal incontinence. All consecutive patients who presented with fecal incontinence to the senior author's clinic were prospectively recruited between June 2009 and September 2010. The severity of their fecal incontinence was assessed by the Wexner and Vaizey scores and anal physiology. Any improvement following a period of sacral transcutaneous electrical nerve stimulation treatment was determined by repeating the scores. In addition, patient satisfaction with the procedure was assessed by using a patient impression score. Twenty female patients with a median age of 57.5 years (range, 30-86) were evaluated. The median follow-up was 10 months (range, 5-12 months). Two patients did not record a change in their Vaizey score. The overall mean Wexner score was 7.9 ± 4.2 before in comparison with 4.0 ± 3.1 after sacral transcutaneous electrical nerve stimulation treatment (p < 0.0001, CI = 2.2-5.7, SE = 0.832). The overall mean Vaizey score was 12.7 ± 5.7 before in comparison with 5.8 ± 5.6 after sacral transcutaneous electrical nerve stimulation treatment (p < 0.0001, CI = 4.5-9.4, SE = 1.162). The pretreatment patient impression score was set at a mean of 1 ± 0 in comparison with 2.8 ± 1.1 after sacral transcutaneous electrical nerve stimulation treatment (p < 0.0001, CI = 1.2-2.3, SE = 0.25). The preliminary results suggest sacral transcutaneous electrical nerve stimulation is a promising noninvasive alternative to existing modalities in the treatment of idiopathic fecal incontinence.

Marrow changes in anorexia nervosa masking the presence of stress fractures on MR imaging.

PubMed

Tins, Bernhard; Cassar-Pullicino, Victor

2006-11-01

Patients with anorexia nervosa (AN) usually have abnormal bone and bone marrow metabolism resulting in osteopenia and serous bone marrow change. There is an increased risk of stress/insufficiency fractures and these can be the first presentation of AN. This case report describes a patient with previously undiagnosed AN who presented with foot pain. The serous bone marrow changes of AN were found to mask the MR imaging features of stress fractures, as both had low T1w and high T2w and STIR signal intensities. Contrast enhancement was not helpful but actually masked fractures. Scintigraphy was helpful. The radiologist might be the first clinician to raise the possibility of AN and should be aware of the difficulties in diagnosing stress fractures in bones with underlying serous bone marrow change. In this severe case of AN even the heel fat pad and the fat pad in Kager's triangle had undergone serous change.

The running athlete: stress fractures, osteitis pubis, and snapping hips.

PubMed

Henning, P Troy

2014-03-01

Pelvic stress fractures, osteitis pubis, and snapping hip syndrome account for a portion of the overuse injuries that can occur in the running athlete. PUBMED SEARCHES WERE PERFORMED FOR EACH ENTITY USING THE FOLLOWING KEYWORDS: snapping hip syndrome, coxa sultans, pelvic stress fracture, and osteitis pubis from 2008 to 2013. Topic reviews, case reports, case series, and randomized trials were included for review. Clinical review. Level 4. Collectively, 188 articles were identified. Of these, 58 were included in this review. Based on the available evidence, the majority of these overuse injuries can be managed non-operatively. Primary treatment should include removal from offending activity, normalizing regional muscle strength/length imbalances and nutritional deficiencies, and mitigating training errors through proper education of the athlete and training staff. C.

The presence of a negative sacral slope in patients with ankylosing spondylitis with severe thoracolumbar kyphosis.

PubMed

Qian, Bang-Ping; Jiang, Jun; Qiu, Yong; Wang, Bin; Yu, Yang; Zhu, Ze-Zhang

2014-11-19

Pelvic retroversion is one of the mechanisms for regulating sagittal balance in patients with a kyphotic deformity. This retroversion is limited by hip extension, which prevents the pelvis from becoming excessively retroverted, achieving a sacral slope of <0°. However, a negative sacral slope can be found in some patients with ankylosing spondylitis with thoracolumbar kyphosis. The purpose of this study was to analyze this finding. We performed a retrospective review of 106 consecutive Chinese Han patients with ankylosing spondylitis with thoracolumbar kyphosis treated at our center from October 2005 to October 2012. Forty-one patients in whom the upper third of the femur was clearly visualized on lateral radiographs were analyzed. Seventeen had a sacral slope of <0° (group A) and twenty-four had a sacral slope of ≥0° (group B). Eight sagittal parameters were measured and compared between the two groups. Correlations among sacral slope, the femoral obliquity angle, and the other sagittal parameters were analyzed. Mean global kyphosis, lumbar lordosis, pelvic tilt, the sagittal vertical axis, and the femoral obliquity angle were significantly larger in group A than in group B, whereas mean pelvic incidence and sacral slope were significantly smaller in group A (p < 0.05 for all). Global kyphosis, lumbar lordosis, pelvic tilt, and the sagittal vertical axis were significantly negatively associated with sacral slope but positively associated with the femoral obliquity angle, whereas pelvic incidence was significantly positively associated with sacral slope but negatively associated with the femoral obliquity angle (p < 0.05 for all). The femoral obliquity angle was significantly negatively associated with sacral slope (p < 0.05). Negative sacral slope does exist in Chinese Han patients with ankylosing spondylitis with thoracolumbar kyphosis. This appears to be caused by severe kyphosis, an initially small sacral slope, and pronounced tilting of the femoral shaft

Sacral root neuromodulation in the treatment of various voiding and storage problems.

PubMed

Shaker, H; Hassouna, M M

1999-01-01

This paper reviews the use of sacral neuromodulation as a treatment modality for patients with bladder dysfunction. The dual functions of the urinary bladder are to act as a reservoir and to evacuate under voluntary control. Bladder dysfunction is a descriptive term describing the loss or the impairment of one or both of these functions. In the first part of the manuscript we describe the different components of sacral neuromodulation: the screening test known as percutaneous nerve evaluation (PNE), which involves screening patients who could potentially benefit from the therapy. Those who show a satisfactory response will have a permanent neuroprosthesis implanted. The technical aspects of both components of neuromodulation are described in detail, as well as the technical difficulties encountered. In the second part we present our long-term results in patients with sacral neuromodulation. Sacral neuromodulation is a safe and efficient therapeutic modality that helps patients with refractory voiding dysfunction restore their bladder function.

Distribution of stress drop, stiffness, and fracture energy over earthquake rupture zones

USGS Publications Warehouse

Fletcher, Joe B.; McGarr, A.

2006-01-01

Using information provided by slip models and the methodology of McGarr and Fletcher (2002), we map static stress drop, stiffness (k = ????/u, where ???? is static stress drop and u is slip), and fracture energy over the slip surface to investigate the earthquake rupture process and energy budget. For the 1994 M6.7 Northridge, 1992 M7.3 Landers, and 1995 M6.9 Kobe earthquakes, the distributions of static stress drop show strong heterogeneity, emphasizing the importance of asperities in the rupture process. Average values of static stress drop are 17, 11, and 4 Mpa for Northridge, Landers, and Kobe, respectively. These values are substantially higher than estimates based on simple crack models, suggesting that the failure process involves the rupture of asperities within the larger fault zone. Stress drop as a function of depth for the Northridge and Landers earthquakes suggests that stress drops are limited by crustal strength. For these two earthquakes, regions of high slip are surrounded by high values of stiffness. Particularly for the Northridge earthquake, the prominent patch of high slip in the central part of the fault is bordered by a ring of high stiffness and is consistent with expectations based on the failure of an asperity loaded at its edge due to exterior slip. Stiffness within an asperity is inversely related to its dimensions. Estimates of fracture energy, based on static stress drop, slip, and rupture speed, were used to investigate the nature of slip weakening at four locations near the hypocenter of the Kobe earthquake for comparison with independent results based on a dynamic model of this earthquake. One subfault updip and to the NE of the hypocenter has a fracture energy of 1.1 MJ/m2 and a slip-weakening distance, Dc, of 0.66 m. Right triangles, whose base and height are Dc and the dynamic stress drop, respectively, approximately overlie the slip-dependent stress given by Ide and Takeo (1997) for the same locations near the hypocenter. The

Effect of Random Natural Fractures on Hydraulic Fracture Propagation Geometry in Fractured Carbonate Rocks

NASA Astrophysics Data System (ADS)

Liu, Zhiyuan; Wang, Shijie; Zhao, Haiyang; Wang, Lei; Li, Wei; Geng, Yudi; Tao, Shan; Zhang, Guangqing; Chen, Mian

2018-02-01

Natural fractures have a significant influence on the propagation geometry of hydraulic fractures in fractured reservoirs. True triaxial volumetric fracturing experiments, in which random natural fractures are created by placing cement blocks of different dimensions in a cuboid mold and filling the mold with additional cement to create the final test specimen, were used to study the factors that influence the hydraulic fracture propagation geometry. These factors include the presence of natural fractures around the wellbore, the dimension and volumetric density of random natural fractures and the horizontal differential stress. The results show that volumetric fractures preferentially formed when natural fractures occurred around the wellbore, the natural fractures are medium to long and have a volumetric density of 6-9%, and the stress difference is less than 11 MPa. The volumetric fracture geometries are mainly major multi-branch fractures with fracture networks or major multi-branch fractures (2-4 fractures). The angles between the major fractures and the maximum horizontal in situ stress are 30°-45°, and fracture networks are located at the intersections of major multi-branch fractures. Short natural fractures rarely led to the formation of fracture networks. Thus, the interaction between hydraulic fractures and short natural fractures has little engineering significance. The conclusions are important for field applications and for gaining a deeper understanding of the formation process of volumetric fractures.

Sacroplasty for symptomatic sacral hemangioma: a novel treatment approach. A case report.

PubMed

Agarwal, V; Sreedher, G; Weiss, K R; Hughes, M A

2013-06-01

Painful vertebral body hemangiomas have been successfully treated with vertebroplasty and kyphoplasty. Sacral hemangiomas are uncommon and as such painful sacral hemangiomas are rare entities. We report what we believe is only the second successful treatment of a painful sacral hemangioma with CT-guided sacroplasty. A 56-year-old woman with a history of right-sided total hip arthroplasty and lipoma excision presented to her orthopedic surgeon with persistent right-sided low back pain which radiated into her buttock and right groin and hindered her ability to walk and perform her activities of daily living. MRIs of the thoracic spine, lumbar spine and pelvis showed numerous lesions with imaging characteristics consistent with multiple hemangiomas including a 2.2×2.1 cm lesion involving the right sacrum adjacent to the right S1 neural foramen. Conservative measures including rest, physical therapy, oral analgesics and right-sided sacroiliac joint steroid injection did not provide significant relief. Given her lack of improvement and the fact that her pain localized to the right sacrum, the patient underwent CT-guided sacroplasty for treatment of a painful right sacral hemangioma. Under CT fluoroscopic guidance, a 10 gauge introducer needle was advanced through the soft tissues of the back to the margin of the lesion. Biopsy was then performed and after appropriate preparation, cement was then introduced through the needle using a separate cement filler cannula. Appropriate filling of the right sacral hemangioma was visualized using intermittent CT fluoroscopy. After injection of approximately 2.5 cc of cement, it was felt that there was near complete filling of the right sacral hemangioma. With satisfactory achievement of cement filling, the procedure was terminated. Pathology from biopsy taken at the time of the procedure was consistent with hemangioma. Image-guided sacroplasty with well-defined endpoints is an effective, minimally invasive and safe procedure

Dynamic Stress Testing Is Unnecessary for Unimalleolar Supination-External Rotation Ankle Fractures with Minimal Fracture Displacement on Lateral Radiographs.

PubMed

Nortunen, Simo; Leskelä, Hannu-Ville; Haapasalo, Heidi; Flinkkilä, Tapio; Ohtonen, Pasi; Pakarinen, Harri

2017-03-15

This study aimed to identify factors from standard radiographs that contributed to the stability of the ankle mortise in patients with isolated supination-external rotation fractures of the lateral malleolus (OTA/AO 44-B). Non-stress radiographs of the mortise and lateral views, without medial clear space widening or incongruity, were prospectively collected for 286 consecutive patients (mean age, 45 years [range, 16 to 85 years]), including 144 female patients (mean age, 50 years [range, 17 to 85 years]) and 142 male patients (mean age, 40 years [range, 16 to 84 years]) from 2 trauma centers. The radiographs were analyzed for fracture morphology by 2 orthopaedic surgeons, who were blinded to each other's measurements and to the results of external rotation stress radiographs (the reference for stability). Factors significantly associated with ankle mortise stability were tested in multiple logistic regression. Receiver operating characteristic analyses were performed for continuous variables to determine optimal thresholds. A sensitivity of >90% was used as the criterion for an optimal threshold. According to external rotation stress radiographs, 217 patients (75.9%) had a stable injury, defined as that with a medial clear space of <5 mm. Independent factors that predicted stable ankle mortise were female sex (odds ratio [OR], 2.5 [95% confidence interval (CI), 1.4 to 4.6]), a posterior diastasis of <2 mm (corresponding with a sensitivity of 0.94 and specificity of 0.39) on lateral radiographs (OR, 10.8 [95% CI, 3.7 to 31.5]), and only 2 fracture fragments (OR, 7.3 [95% CI, 2.1 to 26.3]). When the posterior diastasis was <2 mm and only 2 fracture fragments were present, the probability of a stable ankle mortise was 0.98 for 48 female patients (16.8%) and 0.94 for 37 male patients (12.9%). Patients with noncomminuted lateral malleolar fractures (85 patients [29.7%]) could be diagnosed with a stable ankle mortise without further stress testing, when the fracture

A mechanical model of metatarsal stress fracture during distance running.

PubMed

Gross, T S; Bunch, R P

1989-01-01

A model of metatarsal mechanics has been proposed as a link between the high incidence of second and third metatarsal stress fractures and the large stresses measured beneath the second and third metatarsal heads during distance running. Eight discrete piezoelectric vertical stress transducers were used to record the forefoot stresses of 21 male distance runners. Based upon load bearing area estimates derived from footprints, plantar forces were estimated. Highest force was estimated beneath the second and first metatarsal head (341.1 N and 279.1 N, respectively). Considering the toe as a hinged cantilever and the metatarsal as a proximally attached rigid cantilever allowed estimation of metatarsal midshaft bending strain, shear, and axial forces. Bending strain was estimated to be greatest in the second metatarsal (6662 mu epsilon), a value 6.9 times greater than estimated first metatarsal strain. Predicted third, fourth, and fifth metatarsal strains ranged between 4832 and 5241 mu epsilon. Shear force estimates were also greatest in the second metatarsal (203.0 N). Axial forces were highest in the first metatarsal (593.2 N) due to large hallux forces in relationship to the remaining toes. Although a first order model, these data highlight the structural demands placed upon the second metatarsal, a location of high metatarsal stress fracture incidence during distance running.

Effects of shot-peening residual stresses on the fracture and crack-growth properties of D6AC steel

NASA Technical Reports Server (NTRS)

Elber, W.

1974-01-01

The fracture strength and cyclic crack-growth properties of surface-flawed, shot-peened D6AC steel plate were investigated. For short crack lengths (up to 1.5 mm) simple linear elastic fracture mechanics - based only on applied loading - did not predict the fracture strengths. Also, Paris' Law for cyclic crack growth did not correlate the crack-growth behavior. To investigate the effect of shot-peening, additional fracture and crack-growth tests were performed on material which was precompressed to remove the residual stresses left by the shot-peening. Both tests and analysis show that shot-peening residual stresses influence the fracture and crack-growth properties of the material. This report presents the analytical method of compensating for residual stresses and the fracture and cyclic crack-growth test results and predictions.

Sacral nerve stimulation can be an effective treatment for low anterior resection syndrome.

PubMed

Eftaiha, S M; Balachandran, B; Marecik, S J; Mellgren, A; Nordenstam, J; Melich, G; Prasad, L M; Park, J J

2017-10-01

Sacral nerve stimulation has become a preferred method for the treatment of faecal incontinence in patients who fail conservative (non-operative) therapy. In previous small studies, sacral nerve stimulation has demonstrated improvement of faecal incontinence and quality of life in a majority of patients with low anterior resection syndrome. We evaluated the efficacy of sacral nerve stimulation in the treatment of low anterior resection syndrome using a recently developed and validated low anterior resection syndrome instrument to quantify symptoms. A retrospective review of consecutive patients undergoing sacral nerve stimulation for the treatment of low anterior resection syndrome was performed. Procedures took place in the Division of Colon and Rectal Surgery at two academic tertiary medical centres. Pre- and post-treatment Cleveland Clinic Incontinence Scores and Low Anterior Resection Syndrome scores were assessed. Twelve patients (50% men) suffering from low anterior resection syndrome with a mean age of 67.8 (±10.8) years underwent sacral nerve test stimulation. Ten patients (83%) proceeded to permanent implantation. Median time from anterior resection to stimulator implant was 16 (range 5-108) months. At a median follow-up of 19.5 (range 4-42) months, there were significant improvements in Cleveland Clinic Incontinence Scores and Low Anterior Resection Syndrome scores (P < 0.001). Sacral nerve stimulation improved symptoms in patients suffering from low anterior resection syndrome and may therefore be a viable treatment option. Colorectal Disease © 2017 The Association of Coloproctology of Great Britain and Ireland.

kISMET: Stress analysis and intermediate-scale hydraulic fracturing at the Sanford Underground Research Facility

NASA Astrophysics Data System (ADS)

Dobson, P. F.; Oldenburg, C. M.; Wu, Y.; Cook, P. J.; Kneafsey, T. J.; Nakagawa, S.; Ulrich, C.; Siler, D. L.; Guglielmi, Y.; Ajo Franklin, J. B.; Rutqvist, J.; Daley, T. M.; Birkholzer, J. T.; Wang, H. F.; Lord, N.; Haimson, B. C.; Sone, H.; Vigilante, P.; Roggenthen, W.; Doe, T.; Lee, M.; Ingraham, M. D.; Huang, H.; Mattson, E.; Johnson, T. C.; Zhou, J.; Zoback, M. D.; Morris, J.; White, J. A.; Johnson, P. A.; Coblentz, D. D.; Heise, J.

2017-12-01

In 2015, we established a field test facility at the Sanford Underground Research Facility (SURF), and in 2016 we carried out in situ hydraulic fracturing experiments to characterize the stress field, understand the effects of crystalline rock fabric on fracturing, and gain experience in monitoring using geophysical methods. The kISMET (permeability (k) and Induced Seismicity Management for Energy Technologies) project test site was established in the West Access Drift at the 4850 ft level, 1478 m below ground in phyllite of the Precambrian Poorman Formation. The kISMET team drilled and cored five near-vertical boreholes in a line on 3 m spacing, deviating the two outermost boreholes slightly to create a five-spot pattern around the test borehole centered in the test volume 40 m below the drift invert (floor) at a total depth of 1518 m. Laboratory measurements of core from the center test borehole showed P-wave velocity heterogeneity along each core indicating strong, fine-scale ( 1 cm or smaller) changes in the mechanical properties of the rock. Tensile strength ranges between 3‒7.5 MPa and 5‒12 MPa. Pre-fracturing numerical simulations with a discrete element code were carried out to predict fracture size and magnitude of microseismicity. Field measurements of the stress field were made using hydraulic fracturing, which produced remarkably uniformly oriented fractures suggesting rock fabric did not play a significant role in controlling fracture orientation. Electrical resistivity tomography (ERT) and continuous active seismic source monitoring (CASSM) were deployed in the four monitoring boreholes, and passive seismic accelerometer-based measurements in the West Access Drift were carried out during the generation of a larger fracture (so-called stimulation test). ERT was not able to detect the fracture created, nor did the accelerometers in the drift, but microseismicity was detected for the first (deepest) hydraulic-fracturing stress measurement. Analytical

Comparison of stress fractures of male and female recruits during basic training in the Israeli anti-aircraft forces.

PubMed

Gam, Arnon; Goldstein, Liav; Karmon, Yuval; Mintser, Igor; Grotto, Itamar; Guri, Alex; Goldberg, Avishay; Ohana, Nissim; Onn, Erez; Levi, Yehezkel; Bar-Dayan, Yaron

2005-08-01

In military basic training, stress fractures are a common orthopedic problem. Female recruits have a significantly higher incidence of stress fractures than do male recruits. Because the Israeli Defense Forces opened traditionally male roles in combat units to female recruits, their high risk for stress fractures is of concern. To compare the prevalence of stress fractures during Israeli Defense Forces anti-aircraft basic training among otherwise healthy young male and female recruits, in terms of anatomic distribution and severity. Ten mixed gender batteries, including 375 male recruits and 138 female recruits, carried out basic training in the Israeli anti-aircraft corps between November 1999 and January 2003. Each battery was monitored prospectively for 10 weeks of a basic training course. During that time, recruits who were suspected of having an overuse injury went through a protocol that included an orthopedic specialist physical examination followed by a radionuclide technetium bone scan, which was assessed by consultant nuclear medicine experts. The assessment included the anatomic site and the severity of the fractures, labeled as either high severity or low severity. Stress fractures were significantly more common among female recruits than among male recruits. A total of 42 male (11.2%) and 33 female (23.91%) recruits had positive bone scans for stress fractures (female:male relative ratio, 2.13; p < 0.001). Pelvic, femur, and tibia fractures were significantly more common among female recruits than among male recruits (p < 0.005). Female recruits had significantly more severe fractures in the tibia (p < 0.05). However, there was no significant difference in the severity of stress fractures in the femur or metatarsals between male and female recruits, as assessed by radionuclide uptake. We recommend that different training programs be assigned according to gender, in which female recruits would have a lower level of target strain or a more moderate

Low serum 25-hydroxyvitamin D is associated with increased risk of stress fracture during Royal Marine recruit training.

PubMed

Davey, T; Lanham-New, S A; Shaw, A M; Hale, B; Cobley, R; Berry, J L; Roch, M; Allsopp, A J; Fallowfield, J L

2016-01-01

The aim of this study was to investigate vitamin D status and stress fracture risk during Royal Marine military training. Poor vitamin D status was associated with an increased risk of stress fracture. Vitamin D supplementation may help to reduce stress fracture risk in male military recruits with low vitamin D status. Stress fracture is a common overuse injury in military recruits, including Royal Marine (RM) training in the UK. RM training is recognised as one of the most arduous basic training programmes in the world. Associations have been reported between serum 25-hydroxyvitamin D (25(OH)D) and risk of stress fracture, but the threshold of 25(OH)D for this effect remains unclear. We aimed to determine if serum 25(OH)D concentrations were associated with stress fracture risk during RM training. We prospectively followed 1082 RM recruits (males aged 16-32 years) through the 32-week RM training programme. Troops started training between September and July. Height, body weight and aerobic fitness were assessed at week 1. Venous blood samples were drawn at weeks 1, 15 and 32. Serum samples were analysed for 25(OH)D and parathyroid hormone (PTH). Seventy-eight recruits (7.2 %) suffered a total of 92 stress fractures. Recruits with a baseline serum 25(OH)D concentration below 50 nmol L(-1) had a higher incidence of stress fracture than recruits with 25(OH)D concentration above this threshold (χ(2) (1) = 3.564, p = 0.042; odds ratio 1.6 (95 % confidence interval (CI) 1.0-2.6)). Baseline serum 25(OH)D varied from 47.0 ± 23.7 nmol L(-1) in February, to 97.3 ± 24.6 nmol L(-1) in July (overall mean 69.2 ± 29.2 nmol L(-1), n = 1016). There were weak inverse correlations between serum 25(OH)D and PTH concentrations at week 15 (r = -0.209, p < 0.001) and week 32 (r = -0.214, p < 0.001), but not at baseline. Baseline serum 25(OH)D concentration below 50 nmol L(-1) was associated with an increased risk of stress fracture. Further

Proximal tibia stress fracture with Osteoarthritis of knee - Radiological and functional analysis of one stage TKA with long stem.

PubMed

Soundarrajan, Dhanasekaran; Rajkumar, Natesan; Dhanasekararaja, Palanisamy; Rajasekaran, Shanmuganathan

2018-01-01

Proximal tibia stress fractures with knee osteoarthritis pose a challenging situation. We evaluated the radiological and functional outcome of one-stage total knee arthroplasty (TKA) and long stem for patients with varied grades of knee arthritis and proximal tibia stress fractures.  Methods: We analysed 20 patients from April 2012 to March 2017 with proximal tibia stress fractures associated with knee osteoarthritis of varied grades. Out of 20 patients, five were acute fresh fractures. The mean age was 64 years (range, 52-78) which includes three men and 17 women. Previous surgery in the same limb, rheumatoid arthritis, valgus deformity were excluded. All patients were treated with posterior stabilised TKA with long stem, of which, four patients had screw augmentation for medial tibial bone defect and two patients with malunited fracture at stress fracture site required osteotomy, plating and bone grafting. Two patients had two level stress fracture of tibia in the same leg. The mean follow-up period was 28 (range, 6-60) months. The mean tibiofemoral angle improved from 18.27° varus to 1.8° valgus. The mean knee society score improved from 21.9 (range, -10 to 45) to 82.8 (range, 15-99) [p < 0.05]. The mean Knee Society functional score improved from 15.5 (range, -10 to 40) to 76.8 (range, 10-100) [p < 0.05]. All fractures got united at the last follow-up. One patient had infection and wound dehiscence at six months for which debridement done and had poor functional outcome. TKA with long stem gives excellent outcome, irrespective of severity of arthritis associated with stress fracture. By restoring limb alignment and bypassing the fracture site, it facilitates fracture healing. Early detection and prompt intervention is necessary to prevent the progression to recalcitrant non-union or malunion. © The Authors, published by EDP Sciences, 2018.

Calcaneal stress fracture: an adverse event following total hip and total knee arthroplasty: a report of five cases.

PubMed

Miki, Takaaki; Miki, Takahito; Nishiyama, Akihiro

2014-01-15

Stress fractures have been reported to occur in the pubis, femoral neck, proximal part of the tibia, and fabella during the postoperative period following total knee or total hip arthroplasty. However, to our knowledge, calcaneal stress fractures after total hip or total knee arthroplasty have not been reported in the English-language literature. Most orthopaedic surgeons are not familiar with calcaneal stress fractures that may occur in elderly patients after a total knee or total hip arthroplasty. We retrospectively reviewed the clinical features, imaging findings, and bone mineral content of the proximal part of the femur and the distal end of the radius in five patients who had a calcaneal stress fracture after a total knee or total hip arthroplasty. All patients were women with a mean age of 76.8 years. All fractures occurred in the calcaneus on the same side as the arthroplasty. The fracture appeared at a mean of 10.2 weeks postoperatively. All patients reported heel pain on walking. Swelling and local heat were found in four and three patients, respectively. Pain was elicited by squeezing the calcaneus in all patients. Early radiographs had normal findings in two patients, and an irregular sclerotic line appeared later in the radiographs of all patients. All fractures were treated conservatively. Four fractures healed uneventfully, but one fracture displaced. All patients had osteoporosis. Calcaneal stress fractures during the postoperative period following total knee or total hip arthroplasty may not be as rare as previously thought. Because clinical symptoms of the fracture appear insidiously and radiographic findings are absent or subtle in the early stage, a high index of suspicion is needed for orthopaedic surgeons to make the correct diagnosis. Magnetic resonance imaging or repeated radiographs may be necessary to make the correct diagnosis when no abnormality is apparent on the initial radiograph.

Macro-mesoscopic Fracture and Strength Character of Pre-cracked Granite Under Stress Relaxation Condition

NASA Astrophysics Data System (ADS)

Liu, Junfeng; Yang, Haiqing; Xiao, Yang; Zhou, Xiaoping

2018-05-01

The fracture characters are important index to study the strength and deformation behavior of rock mass in rock engineering. In order to investigate the influencing mechanism of loading conditions on the strength and macro-mesoscopic fracture character of rock material, pre-cracked granite specimens are prepared to conduct a series of uniaxial compression experiments. For parts of the experiments, stress relaxation tests of different durations are also conducted during the uniaxial loading process. Furthermore, the stereomicroscope is adopted to observe the microstructure of the crack surfaces of the specimens. The experimental results indicate that the crack surfaces show several typical fracture characters in accordance with loading conditions. In detail, some cleavage fracture can be observed under conventional uniaxial compression and the fractured surface is relatively rough, whereas as stress relaxation tests are attached, relative slip trace appears between the crack faces and some shear fracture starts to come into being. Besides, the crack faces tend to become smoother and typical terrace structures can be observed in local areas. Combining the macroscopic failure pattern of the specimens, it can be deduced that the duration time for the stress relaxation test contributes to the improvement of the elastic-plastic strain range as well as the axial peak strength for the studied material. Moreover, the derived conclusion is also consistent with the experimental and analytical solution for the pre-peak stage of the rock material. The present work may provide some primary understanding about the strength character and fracture mechanism of hard rock under different engineering environments.

Sacral root neuromodulation in idiopathic nonobstructive chronic urinary retention.

PubMed

Shaker, H S; Hassouna, M

1998-05-01

Sacral root neuromodulation is becoming a superior alternative to the standard treatment of idiopathic nonobstructive urinary retention. We report results in 20 successive patients who underwent sacral foramen implantation to restore bladder function. After an initial, thorough baseline assessment 20 patients 19.43 to 55.66 years old with idiopathic nonobstructive urinary retention underwent percutaneous nerve evaluation. Response was assessed by a detailed voiding diary. Responders underwent implantation with an S3 foramen implant, and were followed 1, 3 and 6 months postoperatively, and every 6 months thereafter. Sacral root neuromodulation restored voiding capability in these patients. Bladders were emptied with minimal post-void residual urine, which decreased from 78.3 to 5.5 to 10.2% of the total voided volume from baseline to postoperative followup. These results were reflected in uroflowmetry and pressure-flow studies, which were almost normal after implantation. Furthermore, the urinary tract infection rate decreased significantly and associated pelvic pain improved substantially. The Beck depression inventory and SF-36 quality of life questionnaire indicated some improvement but reached significance in only 1 item. In addition, cystometrography showed no significant difference after 6 months of implantation compared with baseline values. Complications were minimal and within expectations. Sacral root neuromodulation is an appealing, successful modality for nonobstructive urinary retention. Only patients who have a good response to percutaneous nerve evaluation are candidates for implantation. The high efficacy in patients who undergo implantation, relative simplicity of the procedure and low complication rate make this a treatment breakthrough in this difficult group.

The Macroanatomy of the Sacral Plexus and Its Nerves in Eurasian Eagle Owls (Bubo bubo).

PubMed

Akbulut, Y; Demiraslan, Y; Aslan, K; Coban, A

2016-10-01

This study was carried out to reveal the formation of the sacral plexus in the Eurasian Eagle Owls (Bubo bubo) and the nerves originating from this plexus. Five EEOs, three of them were male and two were female, were provided from Wildlife Rescue and Rehabilitation Center of Kafkas University and used as materials. Following the euthanizing of the animals, abdominal cavity was opened. The nerves of plexus sacrales were dissected and photographed. It was detected that the sacral plexus was formed by the ventral ramus of five synsacral nerves. Moreover, it was determined that the roots of the sacral plexus formed three trunks: the truncus cranialis, the truncus medius and the truncus caudalis in fossa renalis. The availability of the n. ischiofemoralis and the availability of n. parafibularis were detected in the EEOs. Five branches were specified as having segregated from the sacral plexus: the n. cutaneus femoralis caudalis, the mutual root of n. fibularis with n. tibialis (n. ischiadicus), the rami musculares, the n. coxalis caudalis and the ramus muscularis. It was observed that the sacral plexus was linked to the lumbar plexus by the n. furcalis, to the pudendus plexus via the n. bigeminus. Consequently, the anatomic structure of the EEO's sacral plexus, the participating synsacral nerves to plexus and the innervation areas of these nerves were revealed. © 2015 Blackwell Verlag GmbH.

Hydrologic effects of stress-relief fracturing in an Appalachian Valley

USGS Publications Warehouse

Wyrick, Granville G.; Borchers, James W.

1981-01-01

being formed from stress relief. As stress-relief fractures have been described in other valleys of the Appalachian Plateaus, the same aquifer conditions may exist in those valleys.

Dual-dermal-barrier fashion flaps for the treatment of sacral pressure sores.

PubMed

Hsiao, Yen-Chang; Chuang, Shiow-Shuh

2015-02-01

The sacral region is one of the most vulnerable sites for the development of pressure sores. Even when surgical reconstruction is performed, there is a high chance of recurrence. Therefore, the concept of dual-dermal-barrier fashion flaps for sacral pressure sore reconstruction was proposed. From September 2007 to June 2010, nine patients with grade IV sacral pressures were enrolled. Four patients received bilateral myocutaneous V-Y flaps, four patients received bilateral fasciocutaneous V-Y flaps, and one patient received bilateral rotation-advanced flaps for sacral pressure reconstruction. The flaps were designed based on the perforators of the superior gluteal artery in one patient's reconstructive procedure. All flaps' designs were based on dual-dermal-barrier fashion. The mean follow-up time was 16 months (range = 12-25). No recurrence was noted. Only one patient had a complication of mild dehiscence at the middle suture line, occurring 2 weeks after the reconstructive surgery. The dual-dermal fashion flaps are easily duplicated and versatile. The study has shown minimal morbidity and a reasonable outcome.

Sacral neuromodulation in the treatment of the unstable bladder.

PubMed

Bosch, J L

1998-07-01

Sacral neuromodulation as a treatment for urge incontinence in patients with an unstable bladder is the subject of ongoing clinical studies. Although approximately 75% of the patients treated with a permanent sacral foramen electrode implant have experienced significant improvements, it is now also clear that there is an initial failure rate of about 25%. Recent studies have pointed out the importance of improved patient selection on the basis of sex differences, urodynamic parameters and psychological factors. Also, newer forms of test stimulation and permanent electrode implantation are being explored in an effort to improve on the present results.

Dependency of the injection induced seismicity b-value on the stress state of existing fractures

NASA Astrophysics Data System (ADS)

Mukuhira, Y.; Fehler, M. C.; Ito, T.; Asanuma, H.; Häring, M. O.

2017-12-01

The Gutenberg-Richter distribution of earthquake is a power law relationship and it holds for laboratory scale earthquakes (acoustic emission) to subduction zone earthquakes as well as induced seismicity. The gradient of the power law is known as the b-value, which can be considered the ratio of the number of the larger earthquakes to small ones. Larger earthquakes are often observed in low b-value regions, or alternatively a b-value reduction has been observed before some main shocks. Some authors have argued that b-value is negatively correlated with differential stress level. Therefore, a b-value anomaly found in time-space analysis may be used for detection of an area of stress concentration and used for earthquake prediction or hazard risk assessment. In the field of induced seismicity where b-value reduction has also been observed, the physical mechanism of b-value reduction has not been understood well. Since induced seismicity related with fluid injection usually occurs at depths around 1000 5000 m, a significant tectonic mechanism to cause a stress concentration during a short time of hydraulic stimulation might not be expected. We used borehole analysis and focal mechanism information to investigate the stress state on the existing fractures that caused induced seismicity. Then we divide the catalog into the groups with varying normalized shear stress threshold and estimated the b-value. We found that b-value for the events that occurred along higher shear stress fractures were significantly lower (figure 1a) than those from the moderate/lower shear stress fractures (figure 1b). Thus, b-value dependency on the shear stress can be observed for induced seismicity on a reservoir scale. Therefore, we propose that the reason for the observed b-value reductions in induced seismicity on a reservoir scale is the events that occur along higher shear stress fractures. Supposing that the earthquakes occurs along well-orientated fractures, the b-value dependence on

[Stress fractures in disabled athletes' preparation for the paralympic games in Athens, 2004: an assessment].

PubMed

Laboute, E; Druvert, J C; Pailler, D; Piera, J-B

2008-03-01

To identify stress fracture frequency and the associated risk factors in disabled female athletes preparing the Paralympic Games in Athens in 2004. The study is focused on four athletes (including one with a vision impairment) among the 31 women selected to participate in the Paralympic Games. The medical records of selected athletes not having been able to participate in the Games due to a stress fracture were analyzed. One case of stress fracture to the first metatarsal was reported of one below-knee amputee and an additional case to the second metatarsal of one hemiplegic athlete. Two of three athletes with physical disability were unable to participate in the Games because of stress fracture occurring during the preparatory phase. Among four athletes selected to take part in the Paralympic Games. If morphological predispositions are inherent to the sportswomen, the main favouring factor to be retained is their running asymmetry. Training programmes must therefore take this characteristic into account and must not offer heavy-load repetitive exercise (such as endurance or jogging) at the expense of technique. Over-intense training exposes the disabled athlete to this type of pathology and is likely to affect his chances of competing.

Results of the multiwell experiment in situ stresses, natural fractures, and other geological controls on reservoirs

NASA Astrophysics Data System (ADS)

Lorenz, John C.; Warpinski, Norman R.; Teufel, Lawrence W.; Branagan, Paul T.; Sattler, Allan R.; Northrop, David A.

Hundreds of millions of cubic meters of natural gas are locked up in low-permeability, natural gas reservoirs. The Multiwell Experiment (MWX) was designed to characterize such reservoirs, typical of much of the western United States, and to assess and develop a technology for the production of this unconventional resource. Flow-rate tests of the MWX reservoirs indicate a system permeability that is several orders of magnitude higher than laboratory permeability measurements made on matrix-rock sandstones. This enhanced permeability is caused by natural fractures. The single set of fractures present in the reservoirs provides a significant permeability anisotropy that is aligned with the maximum in situ horizontal stress. Hydraulic fractures therefore form parallel to the natural fractures and are consequently an inefficient mechanism for stimulation. Successful stimulation may be possible by perturbing the local stress field with a large hydraulic fracture in one well so that a second hydraulic fracture in an offset well propagates transverse to the natural fracture permeability trend.

The effects of shot-peening residual stresses on the fracture and crack growth properties of D6AC steel

NASA Technical Reports Server (NTRS)

Elber, W.

1973-01-01

The fracture strength and cyclic crack-growth properties of surface-flawed, shot-peened D6AC steel plate were investigated. For short crack lengths (up to 1.5mm) simple linear elastic fracture mechanics - based only on applied loading - did not predict the fracture strengths. Also, Paris' Law for cyclic crack growth did not correlate the crack-growth behavior. To investigate the effect of shot-peening, additional fracture and crack-growth tests were performed on material which was precompressed to remove the residual stresses left by the shot-peening. Both tests and analysis show that the shot-peening residual stresses influence the fracture and crack-growth properties of the material. The analytical method of compensating for residual stresses and the fracture and cyclic crack-growth test results and predictions are presented.

Pore Pressure and Stress Distributions Around a Hydraulic Fracture in Heterogeneous Rock

NASA Astrophysics Data System (ADS)

Gao, Qian; Ghassemi, Ahmad

2017-12-01

One of the most significant characteristics of unconventional petroleum bearing formations is their heterogeneity, which affects the stress distribution, hydraulic fracture propagation and also fluid flow. This study focuses on the stress and pore pressure redistributions during hydraulic stimulation in a heterogeneous poroelastic rock. Lognormal random distributions of Young's modulus and permeability are generated to simulate the heterogeneous distributions of material properties. A 3D fully coupled poroelastic model based on the finite element method is presented utilizing a displacement-pressure formulation. In order to verify the model, numerical results are compared with analytical solutions showing excellent agreements. The effects of heterogeneities on stress and pore pressure distributions around a penny-shaped fracture in poroelastic rock are then analyzed. Results indicate that the stress and pore pressure distributions are more complex in a heterogeneous reservoir than in a homogeneous one. The spatial extent of stress reorientation during hydraulic stimulations is a function of time and is continuously changing due to the diffusion of pore pressure in the heterogeneous system. In contrast to the stress distributions in homogeneous media, irregular distributions of stresses and pore pressure are observed. Due to the change of material properties, shear stresses and nonuniform deformations are generated. The induced shear stresses in heterogeneous rock cause the initial horizontal principal stresses to rotate out of horizontal planes.

Effect of Stress State on Fracture Features

NASA Astrophysics Data System (ADS)

Das, Arpan

2018-02-01

Present article comprehensively explores the influence of specimen thickness on the quantitative estimates of different ductile fractographic features in two dimensions, correlating tensile properties of a reactor pressure vessel steel tested under ambient temperature where the initial crystallographic texture, inclusion content, and their distribution are kept unaltered. It has been investigated that the changes in tensile fracture morphology of these steels are directly attributable to the resulting stress-state history under tension for given specimen dimensions.

The predictive value of the sacral base pressure test in detecting specific types of sacroiliac dysfunction

PubMed Central

Mitchell, Travis D.; Urli, Kristina E.; Breitenbach, Jacques; Yelverton, Chris

2007-01-01

Abstract Objective This study aimed to evaluate the validity of the sacral base pressure test in diagnosing sacroiliac joint dysfunction. It also determined the predictive powers of the test in determining which type of sacroiliac joint dysfunction was present. Methods This was a double-blind experimental study with 62 participants. The results from the sacral base pressure test were compared against a cluster of previously validated tests of sacroiliac joint dysfunction to determine its validity and predictive powers. The external rotation of the feet, occurring during the sacral base pressure test, was measured using a digital inclinometer. Results There was no statistically significant difference in the results of the sacral base pressure test between the types of sacroiliac joint dysfunction. In terms of the results of validity, the sacral base pressure test was useful in identifying positive values of sacroiliac joint dysfunction. It was fairly helpful in correctly diagnosing patients with negative test results; however, it had only a “slight” agreement with the diagnosis for κ interpretation. Conclusions In this study, the sacral base pressure test was not a valid test for determining the presence of sacroiliac joint dysfunction or the type of dysfunction present. Further research comparing the agreement of the sacral base pressure test or other sacroiliac joint dysfunction tests with a criterion standard of diagnosis is necessary. PMID:19674694

[Sacral gigantocellular tumor treated with total sacrectomy and spinal-pelvic fixation].

PubMed

Savić, Milenko

2011-09-01

Total sacrectomy with spinal-pelvic fixation is considered to be a successful approach to the radical surgical treatment of extensive sacral tumors, however, technically very demanding, thus only rarely reported in the literature. We presented a patient with sacral gigantocellular tumor managed successfully using this method but with certain standard operative techniques improvements. A 30-year old patient with a pronounced painful syndrome and sphincter disorders was confirmed to have sacral gigantocellular tumor affecting a greater part of the sacrum. Tumor resection was performed in the first act out off retroperitoneal organs (colon and blood vessels), sacroiliac joints were open by the ventral side, the L5 discus removed, the S2-S5 roots cut off. In the second act, performed three weeks later, sacrectomy was completed by the reconstruction of pelvic ring and spinal-pelvic fixation. Then, the standard technique was modified to provide additional spinal fixation. The results of the operation (duration, blood loss, postoperative deficit) were quite comparable with, and in some aspects even better than the results published in the literature. Total sacrectomy with spinal-pelvic fixation can be a therapy of choice in patients with extensive sacral tumors requaring, however, the multidisciplinary approach and a considerable experience with instrumental spinal stabilization.

The cumulative effect of bisphosphonates and statins on stress fractures. Is it a failure of steroid biosynthesis? Case Report.

PubMed

Dzugan, Sergey S; Dzugan, Sergey A

2016-01-01

Osteoporosis related fractures pose a significant economic and healthcare problem. There is a growing concern about increased numbers of stress or low energy fractures after bisphosphonates therapy. A 65-year-old woman is presented with a stress fracture of the left femur. From our point of view, this fracture was associated with a long-term statin and bisphosphonate therapy. We did not find a similar presentation in medical literature.

Comparative biomechanical evaluation of mono-cortical osteosynthesis systems for condylar fractures using photoelastic stress analysis.

PubMed

Christopoulos, Panos; Stathopoulos, Panagiotis; Alexandridis, Constantinos; Shetty, Vivek; Caputo, Angelo

2012-10-01

Fractures of the condyle account for 20-30% of all mandibular fractures, and are therefore one of the most common facial injuries. Precise evaluation of the mechanical stresses that develop in a fractured mandible is essential, particularly for the testing of systems currently used for stabilisation of the condylar fragment. Photoelastic stress analysis can be used to visualise alterations in the strain that is induced in the mandible by a fracture, and in the osteosynthesis materials used to stabilise it. This method, used on currently used osteosynthesis materials, showed that stabilisation of a subcondylar fracture with a single miniplate does not provide enough stability, whereas the use of two miniplates - properly positioned - offers sufficient stability in all loading conditions. A microplate may be used as a tension-resisting plate with equally good results. Copyright © 2011 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Role of MRI in hip fractures, including stress fractures, occult fractures, avulsion fractures.

PubMed

Nachtrab, O; Cassar-Pullicino, V N; Lalam, R; Tins, B; Tyrrell, P N M; Singh, J

2012-12-01

MR imaging plays a vital role in the diagnosis and management of hip fractures in all age groups, in a large spectrum of patient groups spanning the elderly and sporting population. It allows a confident exclusion of fracture, differentiation of bony from soft tissue injury and an early confident detection of fractures. There is a spectrum of MR findings which in part is dictated by the type and cause of the fracture which the radiologist needs to be familiar with. Judicious but prompt utilisation of MR in patients with suspected hip fractures has a positive therapeutic impact with healthcare cost benefits as well as social care benefits. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Information on stress conditions in the oceanic crust from oval fractures in a deep borehole

USGS Publications Warehouse

Morin, R.H.

1990-01-01

Oval images etched into the wall of a deep borehole were detected in DSDP Hole 504B, eastern equatorial Pacific Ocean, from analysis of an acoustic televiewer log. A systematic inspection of these ovals has identified intriguing consistencies in appearance that cannot be explained satisfactorily by a random, coincidental distribution of pillow lavas. As an alternative hypothesis, Mohr-Coulomb failure criterion is used to account for the generation and orientation of similarly curved, stress-induced fractures. Consequently, these oval features can be interpreted as fractures and related directly to stress conditions in the oceanic crust at this site. The azimuth of the oval center corresponds to the orientation of maximum horizontal principal stress (SH), and the oval width, which spans approximately 180?? of the borehole, is aligned with the azimuth of minimum horizontal principal stress (Sh). The oval height is controlled by the fracture angle and thus is a function of the coefficient of internal friction of the rock. -from Author

Fundamental differences in axial and appendicular bone density in stress fractured and uninjured Royal Marine recruits--a matched case-control study.

PubMed

Davey, Trish; Lanham-New, Susan A; Shaw, Anneliese M; Cobley, Rosalyn; Allsopp, Adrian J; Hajjawi, Mark O R; Arnett, Timothy R; Taylor, Pat; Cooper, Cyrus; Fallowfield, Joanne L

2015-04-01

Stress fracture is a common overuse injury within military training, resulting in significant economic losses to the military worldwide. Studies to date have failed to fully identify the bone density and bone structural differences between stress fractured personnel and controls due to inadequate adjustment for key confounding factors; namely age, body size and physical fitness; and poor sample size. The aim of this study was to investigate bone differences between male Royal Marine recruits who suffered a stress fracture during the 32 weeks of training and uninjured control recruits, matched for age, body weight, height and aerobic fitness. A total of 1090 recruits were followed through training and 78 recruits suffered at least one stress fracture. Bone mineral density (BMD) was measured at the lumbar spine (LS), femoral neck (FN) and whole body (WB) using Dual X-ray Absorptiometry in 62 matched pairs; tibial bone parameters were measured using peripheral Quantitative Computer Tomography in 51 matched pairs. Serum C-terminal peptide concentration was measured as a marker of bone resorption at baseline, week-15 and week-32. ANCOVA was used to determine differences between stress fractured recruits and controls. BMD at the LS, WB and FN sites was consistently lower in the stress fracture group (P<0.001). Structural differences between the stress fracture recruits and controls were evident in all slices of the tibia, with the most prominent differences seen at the 38% tibial slice. There was a negative correlation between the bone cross-sectional area and BMD at the 38% tibial slice. There was no difference in serum CTx concentration between stress fracture recruits and matched controls at any stage of training. These results show evidence of fundamental differences in bone mass and structure in stress fracture recruits, and provide useful data on bone risk factor profiles for stress fracture within a healthy military population. Crown Copyright © 2014. Published

Fabrication and Probabilistic Fracture Strength Prediction of High-Aspect-Ratio Single Crystal Silicon Carbide Microspecimens With Stress Concentration

NASA Technical Reports Server (NTRS)

Nemeth, Noel N.; Evans, Laura J.; Jadaan, Osama M.; Sharpe, William N., Jr.; Beheim, Glenn M.; Trapp, Mark A.

2005-01-01

Single crystal silicon carbide micro-sized tensile specimens were fabricated with deep reactive ion etching (DRIE) in order to investigate the effect of stress concentration on the room-temperature fracture strength. The fracture strength was defined as the level of stress at the highest stressed location in the structure at the instant of specimen rupture. Specimens with an elliptical hole, a circular hole, and without a hole (and hence with no stress concentration) were made. The average fracture strength of specimens with a higher stress concentration was larger than the average fracture strength of specimens with a lower stress concentration. Average strength of elliptical-hole, circular-hole, and without-hole specimens was 1.53, 1.26, and 0.66 GPa, respectively. Significant scatter in strength was observed with the Weibull modulus ranging between 2 and 6. No fractographic examination was performed but it was assumed that the strength controlling flaws originated from etching grooves along the specimen side-walls. The increase of observed fracture strength with increasing stress concentration was compared to predictions made with the Weibull stress-integral formulation by using the NASA CARES/Life code. In the analysis isotropic material and fracture behavior was assumed - hence it was not a completely rigorous analysis. However, even with these assumptions good correlation was achieved for the circular-hole specimen data when using the specimen data without stress concentration as a baseline. Strength was over predicted for the elliptical-hole specimen data. Significant specimen-to-specimen dimensional variation existed in the elliptical-hole specimens due to variations in the nickel mask used in the etching. To simulate the additional effect of the dimensional variability on the probabilistic strength response for the single crystal specimens the ANSYS Probabilistic Design System (PDS) was used with CARES/Life.

Do stress fractures induce hypertrophy of the grafted fibula? A report of three cases received free vascularized fibular graft treatment for tibial defects.

PubMed

Qi, Yong; Sun, Hong-Tao; Fan, Yue-Guang; Li, Fei-Meng; Lin, Zhou-Sheng

2016-06-01

The presence of large segmental defects of the diaphyseal bone is challenging for orthopedic surgeons. Free vascularized fibular grafting (FVFG) is considered to be a reliable reconstructive procedure. Stress fractures are a common complication following this surgery, and hypertrophy is the main physiological change of the grafted fibula. The exact mechanism of hypertrophy is not completely known. To the best of our knowledge, no studies have examined the possible relationship between stress fractures and hypertrophy. We herein report three cases of patients underwent FVFG. Two of them developed stress fractures and significant hypertrophy, while the remaining patient developed neither stress fractures nor significant hypertrophy. This phenomenon indicates that a relationship may exist between stress fractures and hypertrophy of the grafted fibula, specifically, that the presence of a stress fracture may initiate the process of hypertrophy.

Two-View Gravity Stress Imaging Protocol for Nondisplaced Type II Supination External Rotation Ankle Fractures: Introducing the Gravity Stress Cross-Table Lateral View.

PubMed

Boffeli, Troy J; Collier, Rachel C; Gervais, Samuel J

Assessing ankle stability in nondisplaced Lauge-Hansen supination external rotation type II injuries requires stress imaging. Gravity stress mortise imaging is routinely used as an alternative to manual stress imaging to assess deltoid integrity with the goal of differentiating type II from type IV injuries in cases without a posterior or medial fracture. A type II injury with a nondisplaced fibula fracture is typically treated with cast immobilization, and a type IV injury is considered unstable and often requires operative repair. The present case series (two patients) highlights a standardized 2-view gravity stress imaging protocol and introduces the gravity stress cross-table lateral view. The gravity stress cross-table lateral view provides a more thorough evaluation of the posterior malleolus owing to the slight external rotation and posteriorly directed stress. External rotation also creates less bony overlap between the tibia and fibula, allowing for better visualization of the fibula fracture. Gravity stress imaging confirmed medial-sided injury in both cases, confirming the presence of supination external rotation type IV or bimalleolar equivalent fractures. Open reduction and internal fixation was performed, and both patients achieved radiographic union. No further treatment was required at 21 and 33 months postoperatively. Copyright © 2017 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Restoration of bladder function in spastic neuropathic bladder using sacral deafferentation and different techniques of neurostimulation.

PubMed

Schumacher, S; Bross, S; Scheepe, J R; Alken, P; Jünemann, K P

1999-01-01

Conventional sacral anterior root stimulation (SARS) results in simultaneous activation of both the detrusor muscle and the external urethral sphincter. We evaluated the possibilities of different neurostimulation techniques to overcome stimulation induced detrusor-sphincter-dyssynergia and to achieve a physiological voiding. The literature was reviewed on different techniques of sacral anterior root stimulation of the bladder and the significance of posterior rhizotomy in patients with supraconal spinal cord injury suffering from the loss of voluntary bladder control, detrusor hyperreflexia and sphincter spasm. The achievement of selective detrusor activation would improve current sacral neurostimulation of the bladder, including the principle of "poststimulus voiding". This is possible with the application of selective neurostimulation in techniques of anodal block, high frequency block, depolarizing prepulses and cold block. Nowadays, sacral deafferentation is a standard therapy in combination with neurostimulation of the bladder because in conclusion advantages of complete rhizotomy predominate. The combination of sacral anterior root stimulation and sacral deafferentation is a successful procedure for restoration of bladder function in patients with supraconal spinal cord injury. Anodal block technique and cryotechnique are excellent methods for selective bladder activation to avoid detrusor-sphincter-dyssynergia and thus improve stimulation induced voiding.

Weightbearing vs Gravity Stress Radiographs for Stability Evaluation of Supination-External Rotation Fractures of the Ankle.

PubMed

Seidel, Angela; Krause, Fabian; Weber, Martin

2017-07-01

Isolated lateral malleolar fractures may result from a supination-external rotation (SER) injury of the ankle. Stable fractures maintain tibiotalar congruence due to competent medial restraints and can be treated nonoperatively with excellent functional results and long-term prognosis. Stability might be assessed with either stress radiographs or weightbearing radiographs. A consecutive series of patients with closed SER fractures (presumed AO 44-B1) were prospectively enrolled from 2008 to 2015. Patients with clearly unstable fractures (medial clear space more than 7 mm) on the initial nonweightbearing radiograph were excluded and operated on. All other patients were examined with a gravity stress and a weightbearing anteroposterior radiograph. Borderline instability of the fracture was assumed when the medial clear space was 4 to 7 mm. Those were treated nonoperatively. Of 104 patients with isolated lateral malleolar fractures of the SER type, 14 patients were treated operatively because of clear instability (displacement) on the initial radiographs. Of the nonoperative patients, 44 patients demonstrated borderline instability on the gravity stress but stability on the weightbearing radiograph ("gravity borderline"); the remaining 46 were stable in both tests ("gravity stable"). At an average follow-up of 23 months, no significant differences were seen in the American Orthopaedic Foot & Ankle Society hindfoot score (92 points gravity-borderline group vs 93 points gravity-unstable group), the Foot Functional Index score (11 vs 10 points), the Short Form 36 (SF-36) physical component (86 vs 85 points), and SF-36 mental component (84 vs 81 points). Radiographically, all fractures had healed with anatomic congruity of the ankle. Weightbearing radiographs provided a reliable basis to decide about stability and nonoperative treatment in isolated lateral malleolar fractures of the SER type with excellent clinical and radiographic outcome at short-term follow-up. Gravity

HYDRAULIC FRACTURING IN PORUS AND NONPORUS ROCK AND ITS POTENTIAL FOR DETERMINING IN-SITU STRESSES AT GREAT DEPTH.

DTIC Science & Technology

The process of Hydraulic Fracturing as a method of determining in-situ stresses in brittle elastic formations at great depth is analyzed both...theoretically and experimentally. Theoretically, it is found that in attempting to relate the recorded hydraulic fracturing pressures to tectonic stresses...at great depth. The experimental results show that hydraulic fracturing occurred when the internal pressure achieved a critical value that could

Females have a greater incidence of stress fractures than males in both military and athletic populations: a systemic review.

PubMed

Wentz, Laurel; Liu, Pei-Yang; Haymes, Emily; Ilich, Jasminka Z

2011-04-01

The purpose of this study was to review incidence of stress fractures in military and athlete populations and identify factors explaining causes and differences in the incidence among genders. Searches were conducted using several major databases. The studies were included if they were original studies including both male and female subjects and their aim was to identify incidence rates and risk factors contributing to the development of stress fractures. Of several thousand studies, 11 focusing on military populations and 10 on athletes are discussed. In both populations, females had higher incidence of stress fractures, with incidence of approximately 3% and approximately 9.2% for males and females, respectively, in military populations and approximately 6.5% and approximately 9.7%, respectively, in athletes. Factors possibly explaining why females are more susceptible to stress fractures include bone anatomy, lower aerobic capacity, smaller muscle, and poor diet. However, both female recruits and athletes with normal weight and bone health are less likely to develop stress fractures, showing that gender is less important than the overall physical shape/condition.

Ground reaction forces and bone parameters in females with tibial stress fracture.

PubMed

Bennell, Kim; Crossley, Kay; Jayarajan, Jyotsna; Walton, Elizabeth; Warden, Stuart; Kiss, Z Stephen; Wrigley, Tim

2004-03-01

Tibial stress fracture is a common overuse running injury that results from the interplay of repetitive mechanical loading and bone strength. This research project aimed to determine whether female runners with a history of tibial stress fracture (TSF) differ in ground reaction force (GRF) parameters during running, regional bone density, and tibial bone geometry from those who have never sustained a stress fracture (NSF). Thirty-six female running athletes (13 TSF; 23 NSF) ranging in age from 18 to 44 yr were recruited for this cross-sectional study. The groups were well matched for demographic, training, and menstrual parameters. A force platform measured selected GRF parameters (peak and time to peak for vertical impact and active forces, and horizontal braking and propulsive forces) during overground running at 4.0 m.s.(-1). Lumbar spine, proximal femur, and distal tibial bone mineral density were assessed by dual energy x-ray absorptiometry. Tibial bone geometry (cross-sectional dimensions and areas, and second moments of area) was calculated from a computerized tomography scan at the junction of the middle and distal thirds. There were no significant differences between the groups for any of the GRF, bone density, or tibial bone geometric parameters (P > 0.05). Both TSF and NSF subjects had bone density levels that were average or above average compared with a young adult reference range. Factor analysis followed by discriminant function analysis did not find any combinations of variables that differentiated between TSF and NSF groups. These findings do not support a role for GRF, bone density, or tibial bone geometry in the development of tibial stress fractures, suggesting that other risk factors were more important in this cohort of female runners.

Integrated In Situ Stress Estimation by Hydraulic Fracturing, Borehole Observations and Numerical Analysis at the EXP-1 Borehole in Pohang, Korea

NASA Astrophysics Data System (ADS)

Kim, Hanna; Xie, Linmao; Min, Ki-Bok; Bae, Seongho; Stephansson, Ove

2017-12-01

It is desirable to combine the stress measurement data produced by different methods to obtain a more reliable estimation of in situ stress. We present a regional case study of integrated in situ stress estimation by hydraulic fracturing, observations of borehole breakouts and drilling-induced fractures, and numerical modeling of a 1 km-deep borehole (EXP-1) in Pohang, South Korea. Prior to measuring the stress, World Stress Map (WSM) and modern field data in the Korean Peninsula are used to construct a best estimate stress model in this area. Then, new stress data from hydraulic fracturing and borehole observations is added to determine magnitude and orientation of horizontal stresses. Minimum horizontal principal stress is estimated from the shut-in pressure of the hydraulic fracturing measurement at a depth of about 700 m. The horizontal stress ratios ( S Hmax/ S hmin) derived from hydraulic fracturing, borehole breakout, and drilling-induced fractures are 1.4, 1.2, and 1.1-1.4, respectively, and the average orientations of the maximum horizontal stresses derived by field methods are N138°E, N122°E, and N136°E, respectively. The results of hydraulic fracturing and borehole observations are integrated with a result of numerical modeling to produce a final rock stress model. The results of the integration give in situ stress ratios of 1.3/1.0/0.8 ( S Hmax/ S V/ S hmin) with an average azimuth of S Hmax in the orientation range of N130°E-N136°E. It is found that the orientation of S Hmax is deviated by more than 40° clockwise compared to directions reported for the WSM in southeastern Korean peninsula.

The superior gluteal artery perforator flap for reconstruction of sacral sores

PubMed Central

Chen, Weijian; Jiang, Bo; Zhao, Jiaju; Wang, Peiji

2016-01-01

This report describes our experiences using the superior gluteal artery perforator (SGAP) flaps for reconstruction of 2 sacral sore cases. A 47-year-old female patient and a 38-year-old man with sacral sores were treated in our unit. The size of the defects were approximately 5×6 cm2 and 8×9 cm2, the defects were repaired by SGAP flaps. The size of designed was SGAP flaps varied from 7×20 to 9×16 cm2. All flaps survived and healed primary, the texture, functions, and appearance of flaps were satisfactory, and also without region dysfunction of donor and recipient sites. The SGAP flap, which has reliable blood supply, preserves the gluteus maximus muscle and could be transferred simply and safely, is an ideal and reusable method to reconstruct sacral sores with low rate of postoperative recurrence and satisfactory appearance. PMID:27652367

Retention of urine and sacral paraesthesia in anogenital herpes simplex infection.

PubMed

Edis, R H

1981-01-01

Two definite and 2 probable cases of anogenital herpes simplex and sacral radiculitis are described. Symptoms were typical and consisted of paraesthesia and neuralgic pain in the perineum and legs, urinary retention and constipation occurring within several days to a week after an anogenital herpetic eruption. However, at presentation only 1 case had an obvious history of anogenital herpes simplex. Neurological signs were not striking and consisted of a reduced appreciation of light touch and pin prick over the sacral dermatomes and in 2 cases reduced anal sphincter tone. CSF examination in 3 patients showed a lymphocytosis. Bladder catheterisation was required for up to 2 weeks in 2 patients. The paraesthesia persisted for weeks to months. It should be more widely recognised that anogenital herpes simplex, with sacral radiculitis, is probably the commonest cause of acute retention of urine in young sexually active people.

Treatment of stress fracture of the olecranon in throwing athletes with internal fixation through a small incision

PubMed Central

2012-01-01

The present study is a report of retrospective case series of stress fracture of the olecranon. Six patients presented posterior elbow pain in throwing in baseball and softball, but fracture was not diagnosed in radiographs. We detected stress fracture of the olecranon using computed tomographic (CT) scan and treated the patient with internal fixation with a headless cannulated double threaded screw through a small skin incision. All patients returned to competitive level without elbow complaints after the operation. When throwing athletes present with unusual posterior elbow pain and no significant findings on radiographs, a CT scan examination should be performed. We recommend surgical treatment of internal fixation with a screw through a small skin incision, as a good option for stress fracture of the olecranon in order to allow early return to sports activity in competitive athletes. PMID:23241173

Long-term efficacy and safety of sacral nerve stimulation for fecal incontinence.

PubMed

Mellgren, Anders; Wexner, Steven D; Coller, John A; Devroede, Ghislain; Lerew, Darin R; Madoff, Robert D; Hull, Tracy

2011-09-01

Sacral nerve stimulation is effective in the treatment of urinary incontinence and is currently under Food and Drug Administration review in the United States for fecal incontinence. Previous reports have focused primarily on short-term results of sacral nerve stimulation for fecal incontinence. The present study reports the long-term effectiveness and safety of sacral nerve stimulation for fecal incontinence in a large prospective multicenter study. Patients with fecal incontinent episodes more than twice per week were offered participation in this multicentered prospective trial. Patients showing ≥ 50% improvement during test stimulation were offered chronic implantation of the InterStim Therapy system (Medtronic; Minneapolis, MN). The aims of the current report were to provide 3-year follow-up data on patients from that study who underwent sacral nerve stimulation and were monitored under the rigors of an Food and Drug Administration-approved investigational protocol. One hundred thirty-three patients underwent test stimulation with a 90% success rate, of whom 120 (110 females) with a mean age of 60.5 years and a mean duration of fecal incontinence of 7 years received chronic implantation. Mean length of follow-up was 3.1 (range, 0.2-6.1) years, with 83 patients completing all or part of the 3-year follow-up assessment. At 3 years follow-up, 86% of patients (P < .0001) reported ≥ 50% reduction in the number of incontinent episodes per week compared with baseline and the number of incontinent episodes per week decreased from a mean of 9.4 at baseline to 1.7. Perfect continence was achieved in 40% of subjects. The therapy also improved the fecal incontinence severity index. Sacral nerve stimulation had a positive impact on the quality of life, as evidenced by significant improvements in all 4 scales of the Fecal Incontinence Quality of Life instrument at 12, 24, and 36 months of follow-up. The most common device- or therapy-related adverse events through the

A comparative, descriptive study of systemic factors and survival in elderly patients with sacral pressure ulcers.

PubMed

Jaul, Efraim; Menczel, Jacob

2015-03-01

Sacral pressure ulcers (PUs) are a serious complication in frail elderly patients. Thin tissue in the sacral area, low body mass index, and anatomical location contribute to the development of sacral PUs. A comparative, descriptive study was conducted to identify patient systemic factors associated with sacral PUs and to compare survival time in patients with and without PU. All consecutive patients with PUs (n = 77) and without sacral PUs (n = 53) admitted to the skilled nursing department of a geriatric hospital in Jerusalem, Israel between July 1, 2008 and December 31, 2011 were eligible to participate. Charts of previously admitted patients were abstracted and patients were prospectively followed until discharge, death, or the end of the study. Patient demographics, comorbidities, nutritional status, physical and cognitive function (measured using the Reisberg's Functional Assessment Staging Tool [FAST], Stages of Dementia of Alzheimer Scale, and the Glasgow Coma Scale), PU status, number of courses of antibiotic treatment during admission, length of hospitalization, and mortality were compared between patients admitted with and without a sacral PU using descriptive and univariate statistics. Logistic regression models were used to estimate the odds ratio (OR) and 95% confidence intervals (CI) for sacral PU versus without PU by study covariate. The association between sacral PU and survival time was assessed using Kaplan-Meier models. Patients with a sacral PU were significantly older (average age 81.60 ±10.78 versus 77.06±11.19 years old, P = 0.02) and had a higher prevalence of dementia (70% versus 30%, P = 0.007), Parkinson's disease (92.3% versus 7.7%, P = 0.03), and anemia (67.7% versus 32.3%, P = 0.06) than patients admitted without a PU. Patients with a sacral PU also had a lower body mass index (23.1 versus 25.4, P = 0.04), and lower hemoglobin (10.54 versus 11.11, P = 0.03), albumin (26.2 versus 29.7, P = 0.002), and total protein levels (61.3 versus

Fractures and stresses in Bone Spring sandstones

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warpinski, N.R.; Sattler, A.R.; Lorenz, J.C.

This project was a collaboration between Sandia National Laboratories and the Harvey E. Yates Company (Heyco), Roswell, NM, conducted under the auspices of Department of Energy's Oil Recovery Technology Partnership. The project applied Sandia perspectives on the effects of natural fractures, stress, and sedimentology for the stimulation and production of low permeability gas reservoirs to low permeability oil reservoirs, such as those typified by the Bone Spring sandstones of the Delaware Basin, southeast New Mexico. This report details the results and analyses obtained in 1990 from core, logs, stress, and other data taken from three additional development wells. An overallmore » summary gives results from all five wells studied in this project in 1989--1990. Most of the results presented are believed to be new information for the Bone Spring sandstones.« less

Predisposing Risk Factors and Stress Fractures in Division I Cross Country Runners.

PubMed

Giffin, Kaci L; Knight, Kathy B; Bass, Martha A; Valliant, Melinda W

2017-11-11

The purpose of this study was to explore factors associated with increased stress fractures in collegiate cross country runners. Participants in this study were 42 male and female cross country runners at a Division I university. Each athlete completed a questionnaire regarding smoking status, vitamin/mineral intake, previous stress fracture history, birth control usage, menstrual status, and demographic information. Nutritional assessment via a 3-day food record and measurements of whole body, lumbar spine, and hip bone mineral densities (BMD) were also conducted on each athlete. Results indicated that 40% of the female and 35% of the male runners reported a history of stress fracture, and that all of these did not meet the recommended daily energy intake or adequate intakes for calcium or Vitamin D required for their amount of training. Two-tailed t-test found statistically higher incidences of lumbar spine BMD in males and females whose daily calcium and Vitamin D intakes were below minimum requirements as well as for women whose caloric intake was below the required level. When data on the lumbar spine was evaluated, 31% of participants (31.8% of the male and 30% of the female runners) were identified as having osteopenia and 4.8% with osteoporosis. Results warrant a need for future longitudinal studies.

Vertebral Compression Fractures after Lumbar Instrumentation.

PubMed

Granville, Michelle; Berti, Aldo; Jacobson, Robert E

2017-09-29

Lumbar spinal stenosis (LSS) is primarily found in an older population. This is a similar demographic group that develops both osteoporosis and vertebral compression fractures (VCF). This report reviewed a series of patients treated for VCF that had previous lumbar surgery for symptomatic spinal stenosis. Patients that only underwent laminectomy or fusion without instrumentation had a similar distribution of VCF as the non-surgical population in the mid-thoracic, or lower thoracic and upper lumbar spine. However, in the patients that had previous short-segment spinal instrumentation, fractures were found to be located more commonly in the mid-lumbar spine or sacrum adjacent to or within one or two spinal segments of the spinal instrumentation. Adjacent-level fractures that occur due to vertebral osteoporosis after long spinal segment instrumentation has been discussed in the literature. The purpose of this report is to highlight the previously unreported finding of frequent lumbar and sacral osteoporotic fractures in post-lumbar instrumentation surgery patients. Important additional factors found were lack of preventative medical treatment for osteoporosis, and secondary effects related to inactivity, especially during the first year after surgery.

Plate Versus Intramedullary Nail Fixation of Anterior Tibial Stress Fractures: A Biomechanical Study.

PubMed

Markolf, Keith L; Cheung, Edward; Joshi, Nirav B; Boguszewski, Daniel V; Petrigliano, Frank A; McAllister, David R

2016-06-01

Anterior midtibial stress fractures are an important clinical problem for patients engaged in high-intensity military activities or athletic training activities. When nonoperative treatment has failed, intramedullary (IM) nail and plate fixation are 2 surgical options used to arrest the progression of a fatigue fracture and allow bone healing. A plate will be more effective than an IM nail in preventing the opening of a simulated anterior midtibial stress fracture from tibial bending. Controlled laboratory study. Fresh-frozen human tibias were loaded by applying a pure bending moment in the sagittal plane. Thin transverse saw cuts, 50% and 75% of the depth of the anterior tibial cortex, were created at the midtibia to simulate a fatigue fracture. An extensometer spanning the defect was used to measure the fracture opening displacement (FOD) before and after the application of IM nail and plate fixation constructs. IM nails were tested without locking screws, with a proximal screw only, and with proximal and distal screws. Plates were tested with unlocked bicortical screws (standard compression plate) and locked bicortical screws; both plate constructs were tested with the plate edge placed 1 mm from the anterior tibial crest (anterior location) and 5 mm posterior to the crest. For the 75% saw cut depth, the mean FOD values for all IM nail constructs were 13% to 17% less than those for the saw cut alone; the use of locking screws had no significant effect on the FOD. The mean FOD values for all plate constructs were significantly less than those for all IM nail constructs. The mean FOD values for all plates were 28% to 46% less than those for the saw cut alone. Anterior plate placement significantly decreased mean FOD values for both compression and locked plate constructs, but the mean percentage reductions for locked and unlocked plates were not significantly different from each other for either plate placement. The percentage FOD reductions for all plate

Estimation of In Situ Stresses with Hydro-Fracturing Tests and a Statistical Method

NASA Astrophysics Data System (ADS)

Lee, Hikweon; Ong, See Hong

2018-03-01

At great depths, where borehole-based field stress measurements such as hydraulic fracturing are challenging due to difficult downhole conditions or prohibitive costs, in situ stresses can be indirectly estimated using wellbore failures such as borehole breakouts and/or drilling-induced tensile failures detected by an image log. As part of such efforts, a statistical method has been developed in which borehole breakouts detected on an image log are used for this purpose (Song et al. in Proceedings on the 7th international symposium on in situ rock stress, 2016; Song and Chang in J Geophys Res Solid Earth 122:4033-4052, 2017). The method employs a grid-searching algorithm in which the least and maximum horizontal principal stresses ( S h and S H) are varied, and the corresponding simulated depth-related breakout width distribution as a function of the breakout angle ( θ B = 90° - half of breakout width) is compared to that observed along the borehole to determine a set of S h and S H having the lowest misfit between them. An important advantage of the method is that S h and S H can be estimated simultaneously in vertical wells. To validate the statistical approach, the method is applied to a vertical hole where a set of field hydraulic fracturing tests have been carried out. The stress estimations using the proposed method were found to be in good agreement with the results interpreted from the hydraulic fracturing test measurements.

Completed Ulnar Shaft Stress Fracture in a Fast-Pitch Softball Pitcher.

PubMed

Wiltfong, Roger E; Carruthers, Katherine H; Popp, James E

2017-03-01

Stress fractures of the upper extremity have been previously described in the literature, yet reports of isolated injury to the ulna diaphysis or olecranon are rare. The authors describe a case involving an 18-year-old fast-pitch softball pitcher. She presented with a long history of elbow and forearm pain, which was exacerbated during a long weekend of pitching. Her initial physician diagnosed her as having forearm tendinitis. She was treated with nonsurgical means including rest, anti-inflammatory medications, therapy, and kinesiology taping. She resumed pitching when allowed and subsequently had an acute event immediately ceasing pitching. She presented to an urgent care clinic that evening and was diagnosed as having a complete ulnar shaft fracture subsequently needing surgical management. This case illustrates the need for a high degree of suspicion for ulnar stress fractures in fast-pitch soft-ball pitchers with an insidious onset of unilateral forearm pain. Through early identification and intervention, physicians may be able to reduce the risk of injury progression and possibly eliminate the need for surgical management. [Orthopedics. 2017; 40(2):e360-e362.]. Copyright 2016, SLACK Incorporated.

Comparison of two-transsacral-screw fixation versus triangular osteosynthesis for transforaminal sacral fractures.

PubMed

Min, Kyong S; Zamorano, David P; Wahba, George M; Garcia, Ivan; Bhatia, Nitin; Lee, Thay Q

2014-09-01

Transforaminal pelvic fractures are high-energy injuries that are translationally and rotationally unstable. This study compared the biomechanical stability of triangular osteosynthesis vs 2-transsacral-screw fixation in the repair of a transforaminal pelvic fracture model. A transforaminal fracture model was created in 10 cadaveric lumbopelvic specimens. Five of the specimens were stabilized with triangular osteosynthesis, which consisted of unilateral L5-to-ilium lumbopelvic fixation and ipsilateral iliosacral screw fixation. The remaining 5 were stabilized with a 2-transsacral-screw fixation technique that consisted of 2 transsacral screws inserted across S1. All specimens were loaded cyclically and then loaded to failure. Translation and rotation were measured using the MicroScribe 3D digitizing system (Revware Inc, Raleigh, North Carolina). The 2-transsacral-screw group showed significantly greater stiffness than the triangular osteosynthesis group (2-transsacral-screw group, 248.7 N/mm [standard deviation, 73.9]; triangular osteosynthesis group, 125.0 N/mm [standard deviation, 66.9]; P=.02); however, ultimate load and rotational stiffness were not statistically significant. Compared with triangular osteosynthesis fixation, the use of 2 transsacral screws provides a comparable biomechanical stability profile in both translation and rotation. This newly revised 2-transsacral-screw construct offers the traumatologist an alternative method of repair for vertical shear fractures that provides biplanar stability. It also offers the advantage of percutaneous placement in either the prone or supine position. Copyright 2014, SLACK Incorporated.

Bone Geometry as a Predictor of Tissue Fragility and Stress Fracture Risk

DTIC Science & Technology

2004-10-01

eferences ........................................................................ 11 A ppendices ...School of Medicine, New York NY Stress fractures occur among persons with normal bones, no acute injury, and are most common among elite runners and

ADDITIONAL STRESS AND FRACTURE MECHANICS ANALYSES OF PRESSURIZED WATER REACTOR PRESSURE VESSEL NOZZLES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walter, Matthew; Yin, Shengjun; Stevens, Gary

2012-01-01

In past years, the authors have undertaken various studies of nozzles in both boiling water reactors (BWRs) and pressurized water reactors (PWRs) located in the reactor pressure vessel (RPV) adjacent to the core beltline region. Those studies described stress and fracture mechanics analyses performed to assess various RPV nozzle geometries, which were selected based on their proximity to the core beltline region, i.e., those nozzle configurations that are located close enough to the core region such that they may receive sufficient fluence prior to end-of-life (EOL) to require evaluation of embrittlement as part of the RPV analyses associated with pressure-temperaturemore » (P-T) limits. In this paper, additional stress and fracture analyses are summarized that were performed for additional PWR nozzles with the following objectives: To expand the population of PWR nozzle configurations evaluated, which was limited in the previous work to just two nozzles (one inlet and one outlet nozzle). To model and understand differences in stress results obtained for an internal pressure load case using a two-dimensional (2-D) axi-symmetric finite element model (FEM) vs. a three-dimensional (3-D) FEM for these PWR nozzles. In particular, the ovalization (stress concentration) effect of two intersecting cylinders, which is typical of RPV nozzle configurations, was investigated. To investigate the applicability of previously recommended linear elastic fracture mechanics (LEFM) hand solutions for calculating the Mode I stress intensity factor for a postulated nozzle corner crack for pressure loading for these PWR nozzles. These analyses were performed to further expand earlier work completed to support potential revision and refinement of Title 10 to the U.S. Code of Federal Regulations (CFR), Part 50, Appendix G, Fracture Toughness Requirements, and are intended to supplement similar evaluation of nozzles presented at the 2008, 2009, and 2011 Pressure Vessels and Piping (PVP

Proximal tibia stress fracture with Osteoarthritis of knee − Radiological and functional analysis of one stage TKA with long stem

PubMed Central

Soundarrajan, Dhanasekaran; Rajkumar, Natesan; Dhanasekararaja, Palanisamy; Rajasekaran, Shanmuganathan

2018-01-01

Introduction: Proximal tibia stress fractures with knee osteoarthritis pose a challenging situation. We evaluated the radiological and functional outcome of one-stage total knee arthroplasty (TKA) and long stem for patients with varied grades of knee arthritis and proximal tibia stress fractures.  Methods: We analysed 20 patients from April 2012 to March 2017 with proximal tibia stress fractures associated with knee osteoarthritis of varied grades. Out of 20 patients, five were acute fresh fractures. The mean age was 64 years (range, 52–78) which includes three men and 17 women. Previous surgery in the same limb, rheumatoid arthritis, valgus deformity were excluded. All patients were treated with posterior stabilised TKA with long stem, of which, four patients had screw augmentation for medial tibial bone defect and two patients with malunited fracture at stress fracture site required osteotomy, plating and bone grafting. Two patients had two level stress fracture of tibia in the same leg. Results: The mean follow-up period was 28 (range, 6–60) months. The mean tibiofemoral angle improved from 18.27° varus to 1.8° valgus. The mean knee society score improved from 21.9 (range, −10 to 45) to 82.8 (range, 15–99) [p < 0.05]. The mean Knee Society functional score improved from 15.5 (range, −10 to 40) to 76.8 (range, 10–100) [p < 0.05]. All fractures got united at the last follow-up. One patient had infection and wound dehiscence at six months for which debridement done and had poor functional outcome. Conclusion: TKA with long stem gives excellent outcome, irrespective of severity of arthritis associated with stress fracture. By restoring limb alignment and bypassing the fracture site, it facilitates fracture healing. Early detection and prompt intervention is necessary to prevent the progression to recalcitrant non-union or malunion. PMID:29667926

Sacral Peak Pressure in Healthy Volunteers and Patients With Spinal Cord Injury: With and Without Liquid-Based Pad.

PubMed

Duetzmann, Stephan; Forsey, Lynn M; Senft, Christian; Seifert, Volker; Ratliff, John; Park, Jon

2015-01-01

The prevalence of sacral pressure ulcers in patients with spinal cord injuries is high. The sacral area is vulnerable to compressive pressure because of immobility and because the sacrum and posterior superior iliac prominence lie closely under the skin with no muscle layer in between. The aim of this study was to assess peak sacral pressure before and after use of PURAP, a liquid-based pad that covers only the sacral area and can be applied on any bed surface. Healthy volunteers (n = 12) and patients with spinal cord injuries (n = 10) took part; the patients had undergone spine surgery within 7 days before data collection. Participants were in bed, pretest pressure maps were generated, PURAP was placed for 15 minutes, and then posttest pressure maps were generated. Peak pressure was obtained every second and averaged over the entire period. Patients rated whether their comfort had improved when PURAP was in use. For healthy volunteers, mean pretest peak sacral pressure was 74.7 (SD = 16.2) mmHg; the posttest mean was 49.1 (SD = 7.5) mmHg (p < .001, Wilcoxon signed-rank test). For patients with spinal cord injuries, mean pretest peak sacral pressure was 105.7 (SD = 22.4) mmHg; the posttest mean was 81.4 (SD = 18.3) mmHg (p < .001, Wilcoxon signed-rank test). The pad reduced the peak sacral pressure in the patient group by 23% (range = 11%-42%) and in the volunteers by 32% (range = 19%-46%). Overall, 70% of the patients reported increased comfort with PURAP. Peak sacral pressure was reduced when PURAP was used. It covers only the sacral area but could help many patients with spinal cord injury because the prevalence of sacral pressure ulcers is high in this group. PURAP may be economically advantageous in countries and hospitals with limited financial resources needed for more expensive mattresses and cushions.

Tension band plating of a nonunion anterior tibial stress fracture in an athlete.

PubMed

Merriman, Jarrad A; Villacis, Diego; Kephart, Curtis J; Rick Hatch, George F

2013-07-01

The authors present a rare technique of tension band plating of the anterior tibia in the setting of a nonunion stress fracture. Surgical management with an intramedullary nail is a viable and proven option for treating such injuries. However, in treating elite athletes, legitimate concerns exist regarding the surgical disruption of the extensor mechanism and the risk of anterior knee pain associated with intramedullary nail use. The described surgical technique demonstrates the use of tension band plating as an effective treatment of delayed union and nonunion anterior tibial stress fractures in athletes without the potential risks of intramedullary nail insertion. Copyright 2013, SLACK Incorporated.

Recent developments in analysis of crack propagation and fracture of practical materials. [stress analysis in aircraft structures

NASA Technical Reports Server (NTRS)

Hardrath, H. F.; Newman, J. C., Jr.; Elber, W.; Poe, C. C., Jr.

1978-01-01

The limitations of linear elastic fracture mechanics in aircraft design and in the study of fatigue crack propagation in aircraft structures are discussed. NASA-Langley research to extend the capabilities of fracture mechanics to predict the maximum load that can be carried by a cracked part and to deal with aircraft design problems are reported. Achievements include: (1) improved stress intensity solutions for laboratory specimens; (2) fracture criterion for practical materials; (3) crack propagation predictions that account for mean stress and high maximum stress effects; (4) crack propagation predictions for variable amplitude loading; and (5) the prediction of crack growth and residual stress in built-up structural assemblies. These capabilities are incorporated into a first generation computerized analysis that allows for damage tolerance and tradeoffs with other disciplines to produce efficient designs that meet current airworthiness requirements.

Stress Memory in Fluid-Filled Fractures - Insights From Induced Seismicity

NASA Astrophysics Data System (ADS)

Dura-Gomez, I.; Talwani, P.

2007-05-01

Detailed studies of reservoir and injection induced seismicity provide an opportunity to study the characteristics of the fractures associated with fluid-induced seismicity. In 1996, we noted that the first three series of earthquakes with M greater or equal than 5.0 in the vicinity of the Koyna reservoir, occurred only when the reservoir levels had exceeded the previous maxima. In subsequent years, three more similar episodes were noted in the vicinity of the Koyna and the nearby Warna reservoir, without a single repetition in the epicentral location. This behavior was similar to Kaiser effect observed in the laboratory. A similar behavior has been observed in many cases of injection induced seismicity. At the Denver arsenal well in the 1960s and the Soultz, France, hot rock site in the 1990s, among others, seismicity only occurred when the differential pressure, (downhole well borehole pressure excess over the ambient natural pressure) reached a threshold value. These threshold values differed for different wells and depths. The seismicity stopped when the differential pressure was lowered below the threshold value. These observations show that the stress memory (associated with Kaiser effect) observed in the laboratory with small samples, is also displayed in nature where the volume of rocks is from hundreds to thousands of cu.km. The fluid-filled seismogenic fractures near the reservoirs and bore wells, associated with fluid-induced seismicity, seems to behave like a finely tuned, sensitive system that "remember" the largest stress perturbation they have been subjected to. Here we present these observations of stress memory in fluid-filled fractures associated with induced seismicity and suggest possible causes.

Complications and troubleshooting of sacral neuromodulation therapy.

PubMed

Hijaz, Adonis; Vasavada, Sandip

2005-02-01

As evident from the authors' series, the complications of sacral neuromodulation have changed with the introduction of the tined lead and the placement of the generator over the back. In the earlier series, most complications were related to pain at the generator site, which was rare in the authors' series. The posterior location of the generator seems to be better tolerated than the anterior location, which could explain the rare need for revisions for pain at the generator site. Lead migration was observed in 8.4% of the original sacral neuromodulation study group series. This was seen rarely in the authors' series in either stage-one or stage-two revisions. As part of the routine work-up of patients who present with decreased function after a successful period response in stage two, the authors obtain a lateral radiograph of the sacrum; the authors have made the diagnosis of lead migration rarely (1/130; 0.6%). Spinelli and colleagues reported on the use of the tined lead in 15 patients, and observed no lead migration during either the screening period (average 38.8 days) or during follow-up of IPG implantation cases (average 11 months). The total infection rate in the whole series was 18/180 (10%), which was slightly higher than that reported by the sacral neuromodulation study group (6.1%). Revision rates for stage one and stage two were 12.2% and 20%, respectively. The revision rate in the original study group was 33.3%. Thus, with advancing technology, new problems may arise, but the implanting physician should be aware of the ways to evaluate and manage these complications and appropriately troubleshoot patients with suboptimal responses.

An integrated workflow for stress and flow modelling using outcrop-derived discrete fracture networks

NASA Astrophysics Data System (ADS)

Bisdom, K.; Nick, H. M.; Bertotti, G.

2017-06-01

Fluid flow in naturally fractured reservoirs is often controlled by subseismic-scale fracture networks. Although the fracture network can be partly sampled in the direct vicinity of wells, the inter-well scale network is poorly constrained in fractured reservoir models. Outcrop analogues can provide data for populating domains of the reservoir model where no direct measurements are available. However, extracting relevant statistics from large outcrops representative of inter-well scale fracture networks remains challenging. Recent advances in outcrop imaging provide high-resolution datasets that can cover areas of several hundred by several hundred meters, i.e. the domain between adjacent wells, but even then, data from the high-resolution models is often upscaled to reservoir flow grids, resulting in loss of accuracy. We present a workflow that uses photorealistic georeferenced outcrop models to construct geomechanical and fluid flow models containing thousands of discrete fractures covering sufficiently large areas, that does not require upscaling to model permeability. This workflow seamlessly integrates geomechanical Finite Element models with flow models that take into account stress-sensitive fracture permeability and matrix flow to determine the full permeability tensor. The applicability of this workflow is illustrated using an outcropping carbonate pavement in the Potiguar basin in Brazil, from which 1082 fractures are digitised. The permeability tensor for a range of matrix permeabilities shows that conventional upscaling to effective grid properties leads to potential underestimation of the true permeability and the orientation of principal permeabilities. The presented workflow yields the full permeability tensor model of discrete fracture networks with stress-induced apertures, instead of relying on effective properties as most conventional flow models do.

Effectiveness of various isometric exercises at improving bone strength in cortical regions prone to distal tibial stress fractures.

PubMed

Florio, C S

2018-06-01

A computational model was used to compare the local bone strengthening effectiveness of various isometric exercises that may reduce the likelihood of distal tibial stress fractures. The developed model predicts local endosteal and periosteal cortical accretion and resorption based on relative local and global measures of the tibial stress state and its surface variation. Using a multisegment 3-dimensional leg model, tibia shape adaptations due to 33 combinations of hip, knee, and ankle joint angles and the direction of a single or sequential series of generated isometric resultant forces were predicted. The maximum stress at a common fracture-prone region in each optimized geometry was compared under likely stress fracture-inducing midstance jogging conditions. No direct correlations were found between stress reductions over an initially uniform circular hollow cylindrical geometry under these critical design conditions and the exercise-based sets of active muscles, joint angles, or individual muscle force and local stress magnitudes. Additionally, typically favorable increases in cross-sectional geometric measures did not guarantee stress decreases at these locations. Instead, tibial stress distributions under the exercise conditions best predicted strengthening ability. Exercises producing larger anterior distal stresses created optimized tibia shapes that better resisted the high midstance jogging bending stresses. Bent leg configurations generating anteriorly directed or inferiorly directed resultant forces created favorable adaptations. None of the studied loads produced by a straight leg was significantly advantageous. These predictions and the insight gained can provide preliminary guidance in the screening and development of targeted bone strengthening techniques for those susceptible to distal tibial stress fractures. Copyright © 2018 John Wiley & Sons, Ltd.

Stress fractures of the base of the metatarsal bones in young trainee ballet dancers

PubMed Central

Albisetti, Walter; De Bartolomeo, Omar; Tagliabue, Lorenzo; Camerucci, Emanuela; Calori, Giorgio Maria

2009-01-01

Classical ballet is an art form requiring extraordinary physical activity, characterised by rigorous training. These can lead to many overuse injuries arising from repetitive minor trauma. The purpose of this paper is to report our experience in the diagnosis and treatment of stress fractures at the base of the second and third metatarsal bones in young ballet dancers. We considered 150 trainee ballet dancers from the Ballet Schools of "Teatro Alla Scala" of Milan from 2005 to 2007. Nineteen of them presented with stress fractures of the base of the metatarsal bones. We treated 18 dancers with external shockwave therapy (ESWT) and one with pulsed electromagnetic fields (EMF) and low-intensity ultrasound (US); all patients were recommended rest. In all cases good results were obtained. The best approach to metatarsal stress fractures is to diagnose them early through clinical examination and then through X-ray and MRI. ESWT gave good results, with a relatively short time of rest from the patients’ activities and a return to dancing without pain. PMID:19415273

Hydraulic fracturing stress measurement in underground salt rock mines at Upper Kama Deposit

NASA Astrophysics Data System (ADS)

Rubtsova, EV; Skulkin, AA

2018-03-01

The paper reports the experimental results on hydraulic fracturing in-situ stress measurements in potash mines of Uralkali. The selected HF procedure, as well as locations and designs of measuring points are substantiated. From the evidence of 78 HF stress measurement tests at eight measuring points, it has been found that the in-situ stress field is nonequicomponent, with the vertical stresses having value close to the estimates obtained with respect to the overlying rock weight while the horizontal stresses exceed the gravity stresses by 2–3 times.

A novel three-dimensional printed guiding device for electrode implantation of sacral neuromodulation.

PubMed

Cui, Z; Wang, Z; Ye, G; Zhang, C; Wu, G; Lv, J

2018-01-01

The aim was to test the feasibility of a novel three-dimensional (3D) printed guiding device for electrode implantation of sacral neuromodulation (SNM). A 3D printed guiding device for electrode implantation was customized to patients' anatomy of the sacral region. Liquid photopolymer was selected as the printing material. The details of the device designation and prototype building are described. The guiding device was used in two patients who underwent SNM for intractable constipation. Details of the procedure and the outcomes are given. With the help of the device, the test needle for stimulation was placed in the target sacral foramen successfully at the first attempt of puncture in both patients. The time to implant a tined SNM electrode was less than 20 min and no complications were observed. At the end of the screening phase, symptoms of constipation were relieved by more than 50% in both patients and permanent stimulation was established. The customized 3D printed guiding device for implantation of SNM is a promising instrument that facilitates a precise and quick implantation of the electrode into the target sacral foramen. Colorectal Disease © 2017 The Association of Coloproctology of Great Britain and Ireland.

Evolution of stress and strain during 3D folding: application to orthogonal fracture systems in folded turbidites, SW Portugal

NASA Astrophysics Data System (ADS)

Reber, J. E.; Schmalholz, S. M.; Lechmann, S. M.

2009-04-01

We present field data and numerical modeling results which show the evolution of stress and strain patterns during 3D folding resulting in an orthogonal fracture system. The field area is located near Almograve, SW Portugal. The area is part of the Mira Formation which itself is part of the South Portuguese Zone (SPZ). The structural development of the SPZ is characterized by southwest vergent folding and thrust displacement. The metamorphism in the SPZ increases from diagenetic conditions in the southwest to greenschist-facies conditions to the northeast. The Mira Formation is composed of turbiditic layers of Carboniferous age with low sandstone to shale ratio. The data was gathered at three outcrops which show structures similar to chocolate tablet structures in the folded sandstone layers. Chocolate tablet structures are generated under simultaneous extension in two directions and show two fracture systems of the same age which are perpendicular to each other. However, the Mira Formation is located in a convergent area. Also, the outcrops near Almograve show two fracture systems of different age. The fractures orthogonal to the fold axis and the bedding are crosscut by fractures parallel to the fold axis and orthogonal to the bedding. Our hypothesis for the evolution of the observed fracture systems is as follows; the older fractures which are now orthogonal to the fold axis and to the bedding plane were generated during compression while the layers were still approximately horizontal. They are parallel to σ1(i.e. mode 1 fractures). The second and younger fracture family was generated in a phase where there is local extension in the fold limbs. These fractures are orthogonal to the far-field σ1, parallel to the fold axis and perpendicular to the bedding. The shortening direction is constant during the entire folding process. We test our hypothesis with numerical modeling. We use 2D and 3D finite element codes with a mixed formulation for incompressible flow

Tibial plateau fracture following gracilis-semitendinosus anterior cruciate ligament reconstruction: The tibial tunnel stress-riser.

PubMed

Sundaram, R O; Cohen, D; Barton-Hanson, N

2006-06-01

Tibial plateau fractures following anterior cruciate ligament (ACL) reconstruction are extremely rare. This is the first reported case of a tibial plateau fracture following four-strand gracilis-semitendinosus autograft ACL reconstruction. The tibial tunnel alone may behave as a stress riser which can significantly reduce bone strength.

Nutritional factors that influence change in bone density and stress fracture risk among young female cross-country runners.

PubMed

Nieves, Jeri W; Melsop, Kathryn; Curtis, Meredith; Kelsey, Jennifer L; Bachrach, Laura K; Greendale, Gail; Sowers, Mary Fran; Sainani, Kristin L

2010-08-01

To identify nutrients, foods, and dietary patterns associated with stress fracture risk and changes in bone density among young female distance runners. Two-year, prospective cohort study. Observational data were collected in the course of a multicenter randomized trial of the effect of oral contraceptives on bone health. One hundred and twenty-five female competitive distance runners ages 18-26 years. Dietary variables were assessed with a food frequency questionnaire. Bone mineral density and content (BMD/BMC) of the spine, hip, and total body were measured annually by dual x-ray absorptiometry (DEXA). Stress fractures were recorded on monthly calendars, and had to be confirmed by radiograph, bone scan, or magnetic resonance imaging. Seventeen participants had at least one stress fracture during follow-up. Higher intakes of calcium, skim milk, and dairy products were associated with lower rates of stress fracture. Each additional cup of skim milk consumed per day was associated with a 62% reduction in stress fracture incidence (P < .05); and a dietary pattern of high dairy and low fat intake was associated with a 68% reduction (P < .05). Higher intakes of skim milk, dairy foods, calcium, animal protein, and potassium were associated with significant (P < .05) gains in whole-body BMD and BMC. Higher intakes of calcium, vitamin D, skim milk, dairy foods, potassium, and a dietary pattern of high dairy and low fat were associated with significant gains in hip BMD. In young female runners, low-fat dairy products and the major nutrients in milk (calcium, vitamin D, and protein) were associated with greater bone gains and a lower stress fracture rate. Potassium intake was also associated with greater gains in hip and whole-body BMD. Copyright © 2010 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

The effect of concentrated bone marrow aspirate in operative treatment of fifth metatarsal stress fractures; a double-blind randomized controlled trial.

PubMed

Weel, Hanneke; Mallee, Wouter H; van Dijk, C Niek; Blankevoort, Leendert; Goedegebuure, Simon; Goslings, J Carel; Kennedy, John G; Kerkhoffs, Gino M M J

2015-08-20

Fifth metatarsal (MT-V) stress fractures often exhibit delayed union and are high-risk fractures for non-union. Surgical treatment, currently considered as the gold standard, does not give optimal results, with a mean time to fracture union of 12-18 weeks. In recent studies, the use of bone marrow cells has been introduced to accelerate healing of fractures with union problems. The aim of this randomized trial is to determine if operative treatment of MT-V stress fractures with use of concentrated blood and bone marrow aspirate (cB + cBMA) is more effective than surgery alone. We hypothesize that using cB + cBMA in the operative treatment of MT-V stress fractures will lead to an earlier fracture union. A prospective, double-blind, randomized controlled trial (RCT) will be conducted in an academic medical center in the Netherlands. Ethics approval is received. 50 patients will be randomized to either operative treatment with cB + cBMA, harvested from the iliac crest, or operative treatment without cB + cBMA but with a sham-treatment of the iliac crest. The fracture fixation is the same in both groups, as is the post-operative care.. Follow up will be one year. The primary outcome measure is time to union in weeks on X-ray. Secondary outcome measures are time to resumption of work and sports, functional outcomes (SF-36, FAOS, FAAM), complication rate, composition of osteoprogenitors in cB + cBMA and cost-effectiveness. Furthermore, a bone biopsy is taken from every stress fracture and analysed histologically to determine the stage of the stress fracture. The difference in primary endpoint between the two groups is analysed using student's t-test or equivalent. This trial will likely provide level-I evidence on the effectiveness of cB + cBMA in the operative treatment of MT-V stress fractures. Netherlands Trial Register (reg.nr NTR4377 ).

Hydraulic fracture orientation and production/injection induced reservoir stress changes in diatomite waterfloods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wright, C.A.; Conant, R.A.; Golich, G.M.

1995-12-31

This paper summarizes the (preliminary) findings from extensive field studies of hydraulic fracture orientation in diatomite waterfloods and related efforts to monitor the induced surface subsidence. Included are case studies from the Belridge and Lost Hills diatomite reservoirs. The primary purpose of the paper is to document a large volume of tiltmeter hydraulic fracture orientation data that demonstrates waterflood-induced fracture reorientation--a phenomenon not previously considered in waterflood development planning. Also included is a brief overview of three possible mechanisms for the observed waterflood fracture reorientation. A discussion section details efforts to isolate the operative mechanism(s) from the most extensive casemore » study, as well as suggesting a possible strategy for detecting and possibly mitigating some of the adverse effects of production/injection induced reservoir stress changes--reservoir compaction and surface subsidence as well as fracture reorientation.« less

Congenital talipes equinovarus and congenital vertical talus secondary to sacral agenesis.

PubMed

Bray, Jonathan James Hyett; Crosswell, Sebastien; Brown, Rick

2017-05-05

Sacral agenesis is a rare congenital defect which is associated with foot deformities such as congenital talipes equinovarus (CTEV) and less commonly congenital vertical talus (CVT). We report a 3-year-old Caucasian girl who was born with right CTEV and left CVT secondary to sacral agenesis. Her right foot was managed with a Ponseti casting method at 2 weeks, followed by an Achilles tenotomy at 4 months. The left foot was initially managed with a nocturnal dorsi-flexion splint. Both feet remained resistant and received open foot surgery at 10 months producing plantigrade feet with neutral hindfeet. At 19 months, she failed to achieve developmental milestones and examinations revealed abnormal lower limb reflexes. A full body MRI was performed which identified the sacral agenesis. We advocate early MRI of the spine to screen for spinal defects when presented with resistant foot deformities, especially when bilateral. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Long-term results of sacral neuromodulation for women with urinary retention.

PubMed

Dasgupta, Ranan; Wiseman, Oliver J; Kitchen, Neil; Fowler, Clare J

2004-08-01

OBJECTIVE ; To review the long-term results of sacral nerve stimulation in the treatment of women with Fowler's syndrome, over a 6-year period at one tertiary referral centre. Between 1996 and 2002, 26 women with urinary retention were treated by implanting a sacral nerve stimulator. Their case records were reviewed for follow-up, complications and revision procedures, and the most recent uroflowmetry results. There were 20 patients (77%) still voiding spontaneously at the time of review (with two having deactivated their stimulator because of pregnancy). Fourteen patients (54%) required revision surgery, and the most common complications included loss of efficacy, implant-related discomfort and leg pain. The mean postvoid residual volume was 75 mL and mean maximum flow rate 20.8 mL/s. In young women with retention, for whom there is still no alternative to lifelong self-catheterization, sacral neuromodulation is effective for up to 5 years after implantation. However, there was a significant complication rate, in line with other reports, which may be improved by new technical developments.

Effect of Crack Tip Stress Concentration Factor on Fracture Resistance in Vacuum Environment

DTIC Science & Technology

2015-01-20

indicate: (1) in all alloys, the fracture resistance is highest for blunt-notches (smaller Kt), and is lowest for fatigue -sharpened precracked...paths are transgranular and the fracture mode is ductile void coalescence in all cases, irrespective of the stress concentration factor. 20-01-2015...because of corrosion and/or various loading conditions such as fatigue , fretting, abrasion, etc. Also, the geometry of the structure may cause an

[PELVIS/SACRAL syndrome with livedoid haemangioma and amniotic band].

PubMed

Bourrat, E; Lemarchand-Venencie, F; Jacquemont, M-L; El Ghoneimi, A; Wassef, M; Leger, J; Morel, P

2008-12-01

PELVIS or SACRAL syndrome denotes the association of local haemangioma and malformation in the pelvic region. In this paper, we report a case noteworthy on account of the initially livedoid appearance of the haemangioma as well as associated amniotic banding of an upper limb. A newborn male infant underwent left colostomy on the day of birth due to anal imperforation and anomalies of the external genital organs with sexual ambiguity. Examination of the skin and appendages revealed poorly delineated hypopigmentation in the sacrolumbar region and a fibrous groove around the right arm characteristic of amniotic band syndrome. Sacrolumbar and pelvic MRI scans revealed deviation towards the left of the last three sacral vertebrae with no medullary anomalies. Retrograde cystography showed a recto-uretral fistula. Progression of the infant's condition was marked by the appearance during the first month of a flat, violaceous, angiomatous, livedoid lesion in the middle of the buttocks and the perineum and a linear lesion on the rear aspect of the right lower limb. The skin biopsy of this lesion revealed a single capillary lobule at the dermal-hypodermal junction of non-specific appearance but with marked Glut1 expression by endothelial cells highly evocative of infantile haemangioma. Segmented haemangiomas are commonly associated with extracutaneous abnormalities. By analogy with PHACE syndrome, defined as association of segmented facial haemangioma with cerebral, ocular and cardio-aortic abnormalities, PELVIS/SACRAL syndrome denotes the association of segmented haemangioma of the loins (sacrolumbar region, buttocks or perineum=napkin haemangioma) with spinal dysraphia affecting the sacrolumbar spine, the terminal medullary cone, the genitourinary organs and the anal region to different degrees. Diagnosis of haemangioma associated with PELVIS/SACRAL syndrome may be delayed or complicated due to the macular, telangiectasic or livedoid appearance commonly seen. To our

Cyclic Strain Resistance, Stress Response, Fatigue Life, and Fracture Behavior of High Strength Low Alloy Steel 300 M

NASA Astrophysics Data System (ADS)

Manigandan, K.; Srivatsan, T. S.; Tammana, Deepthi; Poorgangi, Behrang; Vasudevan, Vijay K.

2014-05-01

The focus of this technical manuscript is a record of the specific role of microstructure and test specimen orientation on cyclic stress response, cyclic strain resistance, and cyclic stress versus strain response, deformation and fracture behavior of alloy steel 300 M. The cyclic strain amplitude-controlled fatigue properties of this ultra-high strength alloy steel revealed a linear trend for the variation of log elastic strain amplitude with log reversals-to-failure, and log plastic strain amplitude with log reversals-to-failure for both longitudinal and transverse orientations. Test specimens of the longitudinal orientation showed only a marginal improvement over the transverse orientation at equivalent values of plastic strain amplitude. Cyclic stress response revealed a combination of initial hardening for the first few cycles followed by gradual softening for a large portion of fatigue life before culminating in rapid softening prior to catastrophic failure by fracture. Fracture characteristics of test specimens of this alloy steel were different at both the macroscopic and fine microscopic levels over the entire range of cyclic strain amplitudes examined. Both macroscopic and fine microscopic observations revealed fracture to be a combination of both brittle and ductile mechanisms. The underlying mechanisms governing stress response, deformation characteristics, fatigue life, and final fracture behavior are presented and discussed in light of the competing and mutually interactive influences of test specimen orientation, intrinsic microstructural effects, deformation characteristics of the microstructural constituents, cyclic strain amplitude, and response stress.

Rectal ulcer in a patient with VZV sacral meningoradiculitis (Elsberg syndrome).

PubMed

Matsumoto, Hideyuki; Shimizu, Takahiro; Tokushige, Shin-ichi; Mizuno, Hideo; Igeta, Yukifusa; Hashida, Hideji

2012-01-01

This report describes the case of a 55-year-old woman with varicella-zoster virus (VZV) sacral meningoradiculitis (Elsberg syndrome) who presented with herpes zoster in the left S2 dermatome area, urinary retention, and constipation. Lumbar magnetic resonance imaging showed the left sacral nerve root swelling with enhancement. Thereafter, she suddenly showed massive hematochezia and hemorrhagic shock because of a rectal ulcer. To elucidate the relation between Elsberg syndrome and rectal ulcer, accumulation of similar cases is necessary. To avoid severe complications, attention must be devoted to the possibility of rectal bleeding in the early stage of Elsberg syndrome.

Sacral electrical neuromodulation as an alternative treatment option for lower urinary tract dysfunction.

PubMed

Grünewald, Volker; Höfner, Klaus; Thon, Walter F.; Kuczyk, Markus A.; Jonas, Udo

1999-01-01

Temporary electrical stimulation using anal or vaginal electrodes and an external pulse generator has been a treatment modality for urinary urge incontinence for nearly three decades. In 1981 Tanagho and Schmidt introduced chronic electrical stimulation of the sacral spinal nerves using a permanently implanted sacral foramen electrode and a battery powered pulse generator for treatment of different kinds of lower urinary tract dysfunction, refractory to conservative treatment. At our department chronic unilateral electrical stimulation of the S3 sacral spinal nerve has been used for treatment of vesi-courethral dysfunction in 43 patients with a mean postoperative follow up of 43,6 months. Lasting symptomatic improvement by more than 50 % could be achieved in 13 of 18 patients with motor urge incontinence (72,2 %) and in 18 of the 21 patients with urinary retention (85,7 %). Implants offer a sustained therapeutic effect to treatment responders, which is not achieved by temporary neuromodulation. Chronic neuromodulation should be predominantly considered in patients with urinary retention. Furthermore in patients with motor urge incontinence, refusing temporary techniques or in those requiring too much effort to achieve a sustained clinical effect. Despite high initial costs chronic sacral neuromodulation is an economically reasonable treatment option in the long run, when comparing it to the more invasive remaining therapeutic alternatives.

Surface localization of sacral foramina for neuromodulation of bladder function. An anatomical study.

PubMed

Hasan, S T; Shanahan, D A; Pridie, A K; Neal, D E

1996-01-01

A method is described for percutaneous localization of the sacral foramina, for neuromodulation of bladder function. We carried out an anatomical study of 5 male and 5 female human cadaver pelves. Using the described surface markings, needles were placed percutaneously into all sacral foramina from nine different angles. Paths of needle entry were studied by subsequent dissection. We observed that although it was possible to enter any sacral foramen at a wide range of insertion angles, the incidence of nerve root/vascular penetration increased with increasing angle of needle entry. Also, the incidence of nerve root penetration was higher with the medial approach compared with lateral entry. The insertion of a needle into the S1 foramen was associated with a higher incidence of nerve root penetration and presents a potential for arterial haemorrhage. On the other hand the smaller S3 and S4 nerve roots were surrounded by venous plexuses, presenting a potential source of venous haemorrhage during procedures. Our study suggests a new method for identifying the surface markings of sacral foramina and it describes the paths of inserted needles into the respective foramina. In addition, it has highlighted some potential risk factors secondary to needle insertion.

Nonlinear Fluid Migration Patterns in Fractured Reservoirs due to Stress-Pressure Coupling induced Changes in Reservoir Permeabilities

NASA Astrophysics Data System (ADS)

Annewandter, R.; Geiger, S.; Main, I. G.

2011-12-01

Sustainable storage of carbon dioxide (CO2) requires a thorough understanding of injection induced pressure build-up and its effects on the storage formation's integrity, since it determines the cap rock's sealing properties as well as the total storable amount of carbon dioxide. Fractures are abundant in the subsurface and difficult to detect due to their subseismic characteristic. If present in the cap during injection, they can be primary pathways for CO2 leakage. The North Sea is considered as Europe's most important carbon dioxide storage area. However, almost all of the potential storage formations have been exposed to post-glacial lithospheric flexure, possibly causing the generation of new fracture networks in the overburden whilst rebounding. Drawing upon, fast carbon dioxide uprise can be facilitated due to opening of fractures caused by changes in the stress field over time. The overall effective permeability, and hence possible leakage rates, of a fractured storage formation is highly sensitive to the fracture aperture which itself depends on the far field and in situ stress field. For this reason, our in-house general purpose reservoir simulator Complex System Modeling Platform (CSMP++) has been expanded, which is particularly designed to simulate multiphase flow on fractured porous media. It combines finite element (FE) and finite volume (FV) methods on mixed-dimensional hybrid-element meshes. The unstructured FE-FV based scheme allows us to model complex geological structures, such as fractures, at great detail. The simulator uses a compositional model for NaCl-H2O-CO2-systems for compressible fluids for computing thermophysical properties as a function of formation pressure and temperature. A fixed stress-split sequential procedure is being used to calculate coupled fluid flow and geomechanics. Numerical proof of concept studies will be presented showing the impact of fracture opening and closure on fluid migration patterns due to coupled stress

Influence of natural fractures on hydraulic fracture propagation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teufel, L.W.; Warpinski, N.R.

Hydraulic fracturing has become a valuable technique for the stimulation of oil, gas, and geothermal reservoirs in a variety of reservoir rocks. In many applications, only short fractures are needed for economic production. In low-permeability reservoirs, however, long penetrating fractures are generally needed, and in this case, natural fractures can be the cause of many adverse effects during a fracture treatment. Natural fractures can influence the overall geometry and effectiveness of the hydraulic fracture by: (1) arresting the vertical or lateral growth, (2) reducing total fracture length via fluid leakoff, (3) limiting proppant transport and placement, and (4) enhancing themore » creation of multiple or secondary fractures rather than a single planar hydraulic fracture. The result may range from negligible to catastrophic depending on the values of the ancillary treatment and reservoir parameters, such as the treating pressure, in-situ stresses, pore pressure, orientations of the natural fractures relative to principal in-situ stresses, spacing and distribution of the natural fractures, permeability, etc. Field observations from mineback experiments at DOE's Nevada Test Site and the multiwell experiment in Colorado, laboratory tests, and analyses of these data are integrated to describe the complex fracture behavior found and to provide guidelines for predicting when this complex fracturing will occur.« less

Influence of natural fractures on hydraulic fracture propagation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teufel, L.W.; Warpinski, N.R.

Hydraulic fracturing has become a valuable technique for the stimulation of oil, gas, and geothermal reservoirs in a variety of reservoir rocks. In many applications, only short fractures are needed for economic production. In low-permeability reservoirs, however, long penetrating fractures are generally needed, and in this case, natural fractures can be the cause of many adverse effects during a fracture treatment. Natural fractures can influence the overall geometry and effectiveness of the hydraulic fracture by: (1) arresting the vertical or lateral growth, (2) reducing total fracture length via fluid leakoff, (3) limiting proppant transport and placement, and (4) enhancing themore » creation of multiple or secondary fractures rather than a single planar hydraulic fracture. The result may range from negligible to catastrophic depending on the values of the ancillary treatment and reservoir parameters, such as the treating pressure, in-situ stresses, pore pressure, orientations of the natural fractures relative to principle in-situ stresses, spacing and distribution of the natural fractures, permeability, etc. Field observations from mineback experiments at DOE's Nevada Test Site and the multiwell experiment in Colorado, laboratory tests, and analyses of these data are integrated to describe the complex fracture behavior found to an provide guidelines for predicting when this complex fracturing occurs.« less

Range limitation in hip internal rotation and fifth metatarsal stress fractures (Jones fracture) in professional football players.

PubMed

Saita, Yoshitomo; Nagao, Masashi; Kawasaki, Takayuki; Kobayashi, Yohei; Kobayashi, Keiji; Nakajima, Hiroki; Takazawa, Yuji; Kaneko, Kazuo; Ikeda, Hiroshi

2017-04-25

To identify unknown risk factors associated with fifth metatarsal stress fracture (Jones fracture). A case-controlled study was conducted among male Japanese professional football (soccer) players with (N = 20) and without (N = 40) a history of Jones fracture. Injury history and physical examination data were reviewed, and the two groups were compared. Univariate and multivariate logistic regression controlling for age, leg dominance and body mass index were used to obtain odds ratios (ORs) and 95% confidence intervals (CIs) to describe the association between physical examination data and the presence or absence of Jones fractures. From 2000 to 2014, among 162 professional football club players, 22 (13.6%; 21 Asians and one Caucasian) had a history of Jones fracture. Thirteen out of 22 (60%) had a Jones fracture in their non-dominant leg. The mean range of hip internal rotation (HIR) was restricted in players with a history of Jones fracture [25.9° ± 7.5°, mean ± standard deviation (SD)] compared to those without (40.4° ± 11.1°, P < 0.0001). Logistic regression analyses demonstrated that HIR limitation increased the risk of a Jones fracture (OR = 3.03, 95% CI 1.45-6.33, P = 0.003). Subgroup analysis using data prior to Jones fracture revealed a causal relationship, such that players with a restriction of HIR were at high risk of developing a Jones fracture [Crude OR (95% CI) = 6.66 (1.90-23.29), P = 0.003, Adjusted OR = 9.91 (2.28-43.10), P = 0.002]. In addition, right HIR range limitation increased the risks of developing a Jones fracture in the ipsilateral and the contralateral feet [OR = 3.11 (1.35-7.16) and 2.24 (1.22-4.12), respectively]. Similarly, left HIR range limitation increased the risks in the ipsilateral or the contralateral feet [OR (95% CI) = 4.88 (1.56-15.28) and 2.77 (1.08-7.08), respectively]. The restriction of HIR was associated with an increased risk of developing a Jones fracture. Since the HIR range is a

Analysis of foot structure in athletes sustaining proximal fifth metatarsal stress fracture.

PubMed

Hetsroni, Iftach; Nyska, Meir; Ben-Sira, David; Mann, Gideon; Segal, Ofer; Maoz, Guy; Ayalon, Moshe

2010-03-01

In the past, several studies provided anecdotal descriptions of high-arched feet in individuals sustaining proximal fifth metatarsal stress fractures. This relationship has never been supported by scientific evidence. Our objective was to examine whether athletes who sustained this injury had an exceptional static foot structure or dynamic loading pattern. Ten injured professional soccer players who regained full professional activity following a unilateral proximal fifth metatarsal stress fracture and ten control soccer players were examined. Independent variables included static evaluation of foot and arch structure, followed by dynamic plantar foot pressure evaluation. Each variable was compared between injured, contra-lateral uninjured, and control feet. Static measurements of foot and arch structure did not reveal differences among the groups. However, plantar pressure evaluation revealed relative unloading of the fourth metatarsal in injured and uninjured limbs of injured athletes compared with control, while the fifth metatarsal revealed pressure reduction only in the injured limbs of injured athletes. Athletes who sustained proximal fifth metatarsal stress fracture were not characterized by an exceptional static foot structure. Dynamically, lateral metatarsal unloading during stance may either play a role in the pathogenesis of the injury, or alternately represent an adaptive process. Footwear fabrication for previously injured athletes should not categorically address cushioning properties designed for high-arch feet, but rather focus on individual dynamic evaluation of forefoot loading, with less attention applied to static foot and arch characteristics.

Sacral orientation revisited.

PubMed

Peleg, Smadar; Dar, Gali; Steinberg, Nili; Peled, Nathan; Hershkovitz, Israel; Masharawi, Youssef

2007-07-01

A descriptive study of the sacral anatomic orientation (SAO) and its association with pelvic incidence (PI). To introduce the concept of SAO, establish a method for measuring it, and evaluate its association with pelvic orientation. Pelvic orientation (PO) is considered a key factor in spinal shape and balance. Sacral slope (SS), PI, and pelvic tilt (PT) are the most frequently used parameters for evaluating PO. Nevertheless, the association between the anatomic orientation of the sacrum and these parameters has never been established. The aim of the present study is to define the anatomic orientation of the sacrum, to establish a reliable method for measuring it, and to examine its association with PI. SAO was defined as the angle created between the intersection of a line running parallel to the superior endplate surface of the sacrum and a line running between the anterior superior iliac spine (ASIS) and the anterior-superior edge of the symphysis pubis. Methods for measuring SAO and PI on both skeletal populations and living individuals are described. The study was carried out on 424 skeletons (articulated pelves) using a three-dimensional digitizer and on 20 adult individuals using CT three-dimensional images (volume-rendering method). Reliability (intratester and intertester) was assessed using intraclass correlation test. A regression analysis was carried out to evaluate the association between the two measurements. The mean SAO and PI in the human skeletal population were found to be 48.46 degrees +/- 10.17 degrees and 54.08 degrees +/- 12.64 degrees , respectively and of the living individuals (CT) 52.76 degrees +/- 10.31 degrees and 57.14 degrees +/- 13.08 degrees , respectively. SAO and PI measurements were highly correlated (r = -0.824, and r = -0.828, P < 0.001 for skeletal material and living individuals, respectively). PI can be predicted via SAO, i.e., PI = [-0.971 x SAO] + 101.16 degrees . The newly suggested parameter (SAO) may be an important

Peri-anterior cruciate ligament reconstruction femur fracture: a biomechanical analysis of the femoral tunnel as a stress riser.

PubMed

Han, Yung; Sardar, Zeeshan; McGrail, Scott; Steffen, Thomas; Martineau, Paul A

2011-12-01

Sixteen case reports of distal femur fractures as post-operative complications after anterior cruciate ligament (ACL) reconstruction have been described in the literature. The femoral tunnel has been suggested as a potential stress riser for fracture formation. Additionally, double bundle ACL reconstructions may compound this risk. This is the first biomechanical study to examine the significance of a stress riser effect of the femoral tunnel(s) after ACL reconstruction. The hypotheses tested in this study are that the femoral tunnel acts as a stress riser for fracture and that this effect increases with the size of the tunnel (8 mm vs. 10 mm) and with the number of tunnels (1 vs. 2). Femoral tunnels simulating single bundle (SB) hamstring graft (8 mm), bone-patellar tendon-bone graft (10 mm), and double bundle (DB) ACL reconstruction (7, 6 mm) were drilled in fourth-generation saw bones. These three experimental groups and a control group consisting of native saw bones without tunnels were loaded to failure. All fractures occurred through the tunnels in the DB group, whereas fractures did not consistently occur through the tunnels in the SB groups. The mean fracture load was 6,145N ± 471N in the native group, 5,691N ± 198N in the 8 mm SB group, 5,702N ± 282N in the 10 mm SB group, and 4,744N ± 418N in the DB group. The mean fracture load for the DB group was significantly lower when compared to the native, 8 mm SB, and 10 mm SB groups independently (P value = 0.0016, 0.0060, and 0.0038, respectively). The mean fracture loads for neither SB groups were not significantly different from the native group. An anatomically placed femoral tunnel in single bundle ACL reconstruction in our experimental model was not a significant stress riser to fracture, whereas the two femoral tunnels in double bundle ACL reconstruction significantly decreased load to failure. The results support the sparsity of reported peri-ACL reconstruction femur fractures in single femoral

Caprock integrity susceptibility to permeable fracture creation

DOE PAGES

Frash, Luke; Carey, James William; Ickes, Timothy Lee; ...

2017-07-14

Caprock leakage is of crucial concern for environmentally and economically sustainable development of carbon dioxide sequestration and utilization operations. One potential leakage pathway is through fractures or faults that penetrate the caprock. In this study, we investigate the permeability induced by fracturing initially intact Marcellus shale outcrop specimens at stressed conditions using a triaxial direct-shear method. Measurements of induced permeability, fracture geometry, displacement, and applied stresses were all obtained at stressed conditions to investigate the coupled processes of fracturing and fluid flow as may occur in the subsurface. Fracture geometry was directly observed at stressed conditions using X-ray radiography video.more » Numerical simulation was performed to evaluate the stress distribution developed in the experiments. Our experiments show that permeability induced by fracturing is strongly dependent on the stresses at which the fractures are created, the magnitude of shearing displacement, and the duration of flow. The strongest permeability contrast was observed when comparing specimens fractured at low stress to others fractured at higher stress. Measureable fracture permeability decreased by up to 7 orders of magnitude over a corresponding triaxial confining stress range of 3.5 MPa to 30 MPa. These results show that increasing stress, depth, and time are all significant permeability inhibitors that may limit potential leakage through fractured caprock.« less

Caprock integrity susceptibility to permeable fracture creation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frash, Luke; Carey, James William; Ickes, Timothy Lee

Caprock leakage is of crucial concern for environmentally and economically sustainable development of carbon dioxide sequestration and utilization operations. One potential leakage pathway is through fractures or faults that penetrate the caprock. In this study, we investigate the permeability induced by fracturing initially intact Marcellus shale outcrop specimens at stressed conditions using a triaxial direct-shear method. Measurements of induced permeability, fracture geometry, displacement, and applied stresses were all obtained at stressed conditions to investigate the coupled processes of fracturing and fluid flow as may occur in the subsurface. Fracture geometry was directly observed at stressed conditions using X-ray radiography video.more » Numerical simulation was performed to evaluate the stress distribution developed in the experiments. Our experiments show that permeability induced by fracturing is strongly dependent on the stresses at which the fractures are created, the magnitude of shearing displacement, and the duration of flow. The strongest permeability contrast was observed when comparing specimens fractured at low stress to others fractured at higher stress. Measureable fracture permeability decreased by up to 7 orders of magnitude over a corresponding triaxial confining stress range of 3.5 MPa to 30 MPa. These results show that increasing stress, depth, and time are all significant permeability inhibitors that may limit potential leakage through fractured caprock.« less

Clinical outcome of trans-sacral interbody fusion after partial reduction for high-grade l5-s1 spondylolisthesis.

PubMed

Smith, J A; Deviren, V; Berven, S; Kleinstueck, F; Bradford, D S

2001-10-15

A clinical retrospective study was conducted. To evaluate the clinical and radiographic outcome of reduction followed by trans-sacral interbody fusion for high-grade spondylolisthesis. In situ posterior interbody fusion with fibula allograft has improved the fusion rates for patients with high-grade spondylolisthesis. The use of this technique in conjunction with partial reduction has not been reported. Nine consecutive patients underwent treatment of high-grade (Grade 3 or 4) spondylolisthesis with partial reduction followed by posterior interbody fusion using cortical allograft. The average age at the time of surgery was 27 years (range, 8-51 years), and the average follow-up period was 43 months (range, 24-72 months). Before surgery, eight patients had low back pain, seven patients had radiating leg pain, and five patients had hamstring tightness. The average grade of spondylolisthesis by Meyerding grading was 3.9 (range, 3-5). Charts and radiographs were evaluated, and outcomes were collected by use of the modified SRS outcomes instrument. Radiographic indexes demonstrated significant improvement with partial reduction and fusion. The slip angle, as measured from the inferior endplate of L5, improved from 41.2 degrees (range, 24-82 degrees ) before surgery to 21 degrees (range, 5-40 degrees ) after surgery. All the patients were extremely or somewhat satisfied with surgery. The two patients who underwent this operation without initial instrumentation experienced fractures of their interbody grafts. Both of these patients underwent repair of the pseudarthrosis with placement of trans-sacral pedicle screw instrumentation and subsequent fusion. Partial reduction followed by posterior interbody fusion is an effective technique for the management of high-grade spondylolisthesis in pediatric and adult patient populations, as assessed by radiographic and clinical criteria. Pedicle screw instrumentation with the sacral screws capturing L5 is recommended when this

Section modulus is the optimum geometric predictor for stress fractures and medial tibial stress syndrome in both male and female athletes.

PubMed

Franklyn, Melanie; Oakes, Barry; Field, Bruce; Wells, Peter; Morgan, David

2008-06-01

Various tibial dimensions and geometric parameters have been linked to stress fractures in athletes and military recruits, but many mechanical parameters have still not been investigated. Sedentary people, athletes with medial tibial stress syndrome, and athletes with stress fractures have smaller tibial geometric dimensions and parameters than do uninjured athletes. Cohort study; Level of evidence, 3. Using a total of 88 subjects, male and female patients with either a tibial stress fracture or medial tibial stress syndrome were compared with both uninjured aerobically active controls and uninjured sedentary controls. Tibial scout radiographs and cross-sectional computed tomography images of all subjects were scanned at the junction of the midthird and distal third of the tibia. Tibial dimensions were measured directly from the films; other parameters were calculated numerically. Uninjured exercising men have a greater tibial cortical cross-sectional area than do their sedentary and injured counterparts, resulting in a greater value of some other cross-sectional geometric parameters, particularly the section modulus. However, for women, the cross-sectional areas are either not different or only marginally different, and there are few tibial dimensions or geometric parameters that distinguish the uninjured exercisers from the sedentary and injured subjects. In women, the main difference between the groups was the distribution of cortical bone about the centroid as a result of the different values of section modulus. Last, medial tibial stress syndrome subjects had smaller tibial cross-sectional dimensions than did their uninjured exercising counterparts, suggesting that medial tibial stress syndrome is not just a soft-tissue injury but also a bony injury. The results show that in men, the cross-sectional area and the section modulus are the key parameters in the tibia to distinguish exercise and injury status, whereas for women, it is the section modulus only.

Critical Anatomy Relative to the Sacral Suture: A Postoperative Imaging Study After Robotic Sacrocolpopexy.

PubMed

Crisp, Catrina C; Herfel, Charles V; Pauls, Rachel N; Westermann, Lauren B; Kleeman, Steven D

2016-01-01

This study aimed to characterize pertinent anatomy relative to the sacral suture placed at time of robotic sacrocolpopexy using postoperative computed tomography and magnetic resonance imaging. A vascular clip was placed at the base of the sacral suture at the time of robotic sacrocolpopexy. Six weeks postoperatively, subjects returned for a computed tomography scan and magnetic resonance imaging. Ten subjects completed the study. The middle sacral artery and vein coursed midline or to the left of midline in all the subjects. The left common iliac vein was an average of 26 mm from the sacral suture. To the right of the suture, the right common iliac artery was 18 mm away. Following the right common iliac artery to its bifurcation, the right internal iliac was on average 10 mm from the suture. The bifurcations of the inferior vena cava and the aorta were 33 mm and 54 mm further cephalad, respectively.The right ureter, on average, was 18 mm from the suture. The thickness of the anterior longitudinal ligament was 2 mm.The mean angle of descent of the sacrum was 70 degrees. Lastly, we found that 70% of the time, a vertebral body was directly below the suture; the disc was noted in 30%. We describe critical anatomy surrounding the sacral suture placed during robotic sacrocolpopexy. Proximity of both vascular and urologic structures within 10 to 18 mm, as well as anterior ligament thickness of only 2 mm highlights the importance of adequate exposure, careful dissection, and surgeon expertise.

Paraspinal Transposition Flap for Reconstruction of Sacral Soft Tissue Defects: A Series of 53 Cases from a Single Institute

PubMed Central

Chattopadhyay, Debarati; Agarwal, Akhilesh Kumar; Guha, Goutam; Bhattacharya, Nirjhar; Chumbale, Pawan K; Gupta, Souradip; Murmu, Marang Buru

2014-01-01

Study Design Case series. Purpose To describe paraspinal transposition flap for coverage of sacral soft tissue defects. Overview of Literature Soft tissue defects in the sacral region pose a major challenge to the reconstructive surgeon. Goals of sacral wound reconstruction are to provide a durable skin and soft tissue cover adequate for even large sacral defects; minimize recurrence; and minimize donor site morbidity. Various musculocutaneous and fasciocutanous flaps have been described in the literature. Methods The flap was applied in 53 patients with sacral soft tissue defects of diverse etiology. Defects ranged in size from small (6 cm×5 cm) to extensive (21 cm×10 cm). The median age of the patients was 58 years (range, 16-78 years). Results There was no flap necrosis. Primary closure of donor sites was possible in all the cases. The median follow up of the patients was 33 months (range, 4-84 months). The aesthetic outcomes were acceptable. There has been no recurrence of pressure sores. Conclusions The authors conclude that paraspinal transposition flap is suitable for reconstruction of large sacral soft tissue defects with minimum morbidity and excellent long term results. PMID:24967044

Effect of far-field stresses and residual stresses incorporation in predicting fracture toughness of carbon nanotube reinforced yttria stabilized zirconia

NASA Astrophysics Data System (ADS)

Mahato, Neelima; Nisar, Ambreen; Mohapatra, Pratyasha; Rawat, Siddharth; Ariharan, S.; Balani, Kantesh

2017-10-01

Yttria-stabilized zirconia (YSZ) is a potential thermal insulating ceramic for high temperature applications (>1000 °C). YSZ reinforced with multi-walled carbon nanotubes (MWNTs) was processed via spark plasma sintering to produce dense, crack-free homogeneous sample and avoid any degradation of MWNTs when sintered using conventional routes. Despite porosity, the addition of MWNT has a profound effect in improving the damage tolerance of YSZ by allowing the retention of tetragonal phase. However, at some instances, the crack lengths in the MWNT reinforced YSZ matrices have been found to be longer than the standalone counterparts. Therefore, it becomes inappropriate to apply Anstis equation to calculate fracture toughness values. In this regard, a combined analytical cum numerical method is used to estimate the theoretical fracture toughness and quantitatively analyze the mechanics of matrix cracking in the reinforced composite matrices incorporating the effects of various factors (such as far-field stresses, volume fraction of MWNTs, change in the modulus and Poisson's ratio values along with the increase in porosity, and bridging and phase transformation mechanism) affecting the fracture toughness of YSZ-MWNT composites. The results suggest that the incorporation of far-field stresses cannot be ignored in estimating the theoretical fracture toughness of YSZ-MWNT composites.

Residual stress and damage-induced critical fracture on CO2 laser treated fused silica

NASA Astrophysics Data System (ADS)

Matthews, M. J.; Stolken, J. S.; Vignes, R. M.; Norton, M. A.; Yang, S.; Cooke, J. D.; Guss, G. M.; Adams, J. J.

2009-10-01

Localized damage repair and polishing of silica-based optics using mid- and far-IR CO2 lasers has been shown to be an effective method for increasing optical damage threshold in the UV. However, it is known that CO2 laser heating of silicate surfaces can lead to a level of residual stress capable of causing critical fracture either during or after laser treatment. Sufficient control of the surface temperature as a function of time and position is therefore required to limit this residual stress to an acceptable level to avoid critical fracture. In this work we present the results of 351 nm, 3ns Gaussian damage growth experiments within regions of varying residual stress caused by prior CO2 laser exposures. Thermally stressed regions were non-destructively characterized using polarimetry and confocal Raman microscopy to measure the stress induced birefringence and fictive temperature respectively. For 1~40s square pulse CO2 laser exposures created over 0.5-1.25kW/cm2 with a 1-3mm 1/e2 diameter beam (Tmax~1500-3000K), the critical damage site size leading to fracture increases weakly with peak temperature, but shows a stronger dependence on cooling rate, as predicted by finite element hydrodynamics simulations. Confocal micro-Raman was used to probe structural changes to the glass over different thermal histories and indicated a maximum fictive temperature of 1900K for Tmax>=2000K. The effect of cooling rate on fictive temperature caused by CO2 laser heating are consistent with finite element calculations based on a Tool-Narayanaswamy relaxation model.

Biomechanical Factors in the Etiology of Tibial Stress Fractures

DTIC Science & Technology

2006-08-01

stiffness in these runners. A “stiff” runner will spend less time in contact with the ground (Farley and Gonzalez, 1996 ) and will attenuate less shock...between the leg and the head (McMahon et al., 1987). This is in agreement with the findings of Farley and Gonzalez ( 1996 ) who suggested lower...Army Natick Research and Development Laboratories. Brukner, P., Bradshaw, C., Khan, K., White, S. and Crossley, K. ( 1996 ) Stress fractures: a

A large giant cell tumor of the sacrum. Advantage of an abdomino-sacral approach.

PubMed

Alla, Abubakr H; Mahadi, Seif I; Elhassan, Ahmed M; Ahmed, Mohamed E

2005-01-01

We report a case of giant cell tumor of the sacrum, presenting with sacral pain, swelling, and change of bowel habits. Rectal examination revealed a huge retrorectal mass fixed to the sacrum but not to the wall of the rectum. Abdominal ultrasonography, computed tomography CT scan, and magnetic resonance imaging MRI showed a huge pelvic mass invading the sacrum. Exploration via posterior sacral approach was not successful due to both, extensive bleeding and difficult accessibility. Re-exploration was carried out 2 days later with the patient in lithotomy position. Using abdomino-sacral approach the mass together with part of the sacrum and the whole coccyx were excised. Histopathology reported giant cell tumor of the sacrum with no evidence of mitosis. The patient was symptomless 12 months after surgery and on follow up.

Long-term durability of sacral nerve stimulation therapy for chronic fecal incontinence.

PubMed

Hull, Tracy; Giese, Chad; Wexner, Steven D; Mellgren, Anders; Devroede, Ghislain; Madoff, Robert D; Stromberg, Katherine; Coller, John A

2013-02-01

Limited data have been published regarding the long-term results of sacral nerve stimulation, or sacral neuromodulation, for severe fecal incontinence. The aim was to assess the outcome of sacral nerve stimulation with the use of precise tools and data collection, focusing on the long-term durability of the therapy. Five-year data were analyzed. Patients entered in a multicenter, prospective study for fecal incontinence were followed at 3, 6, and 12 months and annually after device implantation. Patients with chronic fecal incontinence in whom conservative treatments had failed or who were not candidates for more conservative treatments were selected. Patients with ≥ 50% improvement over baseline in fecal incontinence episodes per week during a 14-day test stimulation period received sacral nerve stimulation therapy. Patients were assessed with a 14-day bowel diary and Fecal Incontinence Quality of Life and Fecal Incontinence Severity Index questionnaires. Therapeutic success was defined as ≥ 50% improvement over baseline in fecal incontinence episodes per week. All adverse events were collected. A total of 120 patients (110 women; mean age, 60.5 years) underwent implantation. Seventy-six of these patients (63%) were followed a minimum of 5 years (maximum, longer than 8 years) and are the basis for this report. Fecal incontinence episodes per week decreased from a mean of 9.1 at baseline to 1.7 at 5 years, with 89% (n = 64/72) having ≥ 50% improvement (p < 0.0001) and 36% (n = 26/72) having complete continence. Fecal Incontinence Quality of Life scores also significantly improved for all 4 scales between baseline and 5 years (n = 70; p < 0.0001). Twenty-seven of the 76 (35.5%) patients required a device revision, replacement, or explant. The therapeutic effect and improved quality of life for fecal incontinence is maintained 5 years after sacral nerve stimulation implantation and beyond. Device revision, replacement, or explant rate was acceptable, but future

Faulting, fracturing and in situ stress prediction in the Ahnet Basin, Algeria — a finite element approach

NASA Astrophysics Data System (ADS)

Beekman, Fred; Badsi, Madjid; van Wees, Jan-Diederik

2000-05-01

Many low-efficiency hydrocarbon reservoirs are productive largely because effective reservoir permeability is controlled by faults and natural fractures. Accurate and low-cost information on basic fault and fracture properties, orientation in particular, is critical in reducing well costs and increasing well recoveries. This paper describes how we used an advanced numerical modelling technique, the finite element method (FEM), to compute site-specific in situ stresses and rock deformation and to predict fracture attributes as a function of material properties, structural position and tectonic stress. Presented are the numerical results of two-dimensional, plane-strain end-member FEM models of a hydrocarbon-bearing fault-propagation-fold structure. Interpretation of the modelling results remains qualitative because of the intrinsic limitations of numerical modelling; however, it still allows comparisons with (the little available) geological and geophysical data. In all models, the weak mechanical strength and flow properties of a thick shale layer (the main seal) leads to a decoupling of the structural deformation of the shallower sediments from the underlying sediments and basement, and results in flexural slip across the shale layer. All models predict rock fracturing to initiate at the surface and to expand with depth under increasing horizontal tectonic compression. The stress regime for the formation of new fractures changes from compressional to shear with depth. If pre-existing fractures exist, only (sub)horizontal fractures are predicted to open, thus defining the principal orientation of effective reservoir permeability. In models that do not include a blind thrust fault in the basement, flexural amplification of the initial fold structure generates additional fracturing in the crest of the anticline controlled by the material properties of the rocks. The folding-induced fracturing expands laterally along the stratigraphic boundaries under enhanced

Bone geometry, strength, and muscle size in runners with a history of stress fracture.

PubMed

Popp, Kristin L; Hughes, Julie M; Smock, Amanda J; Novotny, Susan A; Stovitz, Steven D; Koehler, Scott M; Petit, Moira A

2009-12-01

Our primary aim was to explore differences in estimates of tibial bone strength, in female runners with and without a history of stress fractures. Our secondary aim was to explore differences in bone geometry, volumetric density, and muscle size that may explain bone strength outcomes. A total of 39 competitive distance runners aged 18-35 yr, with (SFX, n = 19) or without (NSFX, n = 20) a history of stress fracture were recruited for this cross-sectional study. Peripheral quantitative computed tomography (XCT 3000; Orthometrix, White Plains, NY) was used to assess volumetric bone mineral density (vBMD, mg x mm(-3)), bone area (ToA, mm(2)), and estimated compressive bone strength (bone strength index (BSI) = ToA x total volumetric density (ToD(2))) at the distal tibia (4%). Total (ToA, mm(2)) and cortical (CoA, mm(2)) bone area, cortical vBMD, and estimated bending strength (strength-strain index (SSIp), mm(3)) were measured at the 15%, 25%, 33%, 45%, 50%, and 66% sites. Muscle cross-sectional area (MCSA) was measured at the 50% and 66% sites. Participants in the SFX group had significantly smaller (7%-8%) CoA at the 45%, 50%, and 66% sites (P stress fracture. However, the lower strength was appropriate for the smaller muscle size, suggesting that interventions to reduce stress fracture risk might be aimed at improving muscle size and strength.

Spinopelvic Fixation of Sacroiliac Joint Fractures and Fracture-Dislocations: A Clinical 8 Years Follow-Up Study.

PubMed

Sobhan, Mohammad R; Abrisham, Seyed Mohammad J; Vakili, Mahmood; Shirdel, Saeed

2016-10-01

Pelvic ring injuries and sacroiliac dislocations have significant impacts on patient's quality of life. Several techniques have been described for posterior pelvic fixation. The current study has been designed to evaluate the spinopelvic method of fixation for sacroiliac fractures and fracture-dislocations. Between January 2006 and December 2014, 14 patients with sacroiliac joint fractures, dislocation and fracture-dislocation were treated by Spinopelvic fixation at Shahid Sadoughi Training Hospital, Yazd, Iran. Patients were seen in follow up, on average, out to 32 months after surgery. Computed tomographic (CT) scans of patients with sacral fractures were reviewed to determine the presence of injuries. A functional assessment of the patients was performed using Majeed's score. Patient demographics, reduction quality, loss of fixation, outcomes and complications, return to activity, and screw hardware characteristics are described. The injury was unilateral in 11 (78.5%) patients and bilateral in 3 (21.5%). Associated injuries were present in all patients, including fractures, dislocation and abdominal injuries. Lower limb length discrepancy was less than 10 mm in all patients except two. Displacement, as a measure of quality of reduction was less than 5 mm in 13 patients. The mean Majeed score was 78/100. Wound infection and hardware failure were observed in 3 (21.4%) and 1 (7.1%) cases, respectively. In this study most patients (85%) return to work postoperatively. According to the findings, spinopelvic fixation is a safe and effective technique for treatment of sacroiliac injuries. This method can obtain early partial to full weight bearing and possibly reduce the complications.

Dual-energy X-ray absorptiometry derived structural geometry for stress fracture prediction in male U.S. Marine Corps recruits.

PubMed

Beck, T J; Ruff, C B; Mourtada, F A; Shaffer, R A; Maxwell-Williams, K; Kao, G L; Sartoris, D J; Brodine, S

1996-05-01

A total of 626 U.S. male Marine Corps recruits underwent anthropometric measurements and dual-energy X-ray absorptiometry (DXA) scans of the femoral midshaft and the distal third of the tibia prior to a 12 week physical training program. Conventionally obtained frontal plane DXA scan data were used to measure the bone mineral density (BMD) as well as to derive the cross-sectional area, moment of inertia, section modulus, and bone width in the femur, tibia, and fibula. During training, 23 recruits (3.7%) presented with a total of 27 radiologically confirmed stress fractures in various locations in the lower extremity. After excluding 16 cases of shin splints, periostitis, and other stress reactions that did not meet fracture definition criteria, we compared anthropometric and bone structural geometry measurements between fracture cases and the remaining 587 normals. There was no significant difference in age (p = 0.8), femur length (p = 0.2), pelvic width (p = 0.08), and knee width at the femoral condyles (p = 0.06), but fracture cases were shorter (p = 0.01), lighter (p = 0.0006), and smaller in most anthropometric girth dimensions (p < 0.04). Fracture case bone cross-sectional areas (p < 0.001), moments of inertia (p < 0.001), section moduli (p < 0.001), and widths (p < 0.001) as well as BMD (p < 0.03) were significantly smaller in the tibia and femur. After correcting for body weight differences, the tibia cross-sectional area (p = 0.03), section modulus (p = 0.05), and width (p = 0.03) remained significantly smaller in fracture subjects. We conclude that both small body weight and small diaphyseal dimensions relative to body weight are factors predisposing to the development of stress fractures in this population. These results suggest that bone structural geometry measurements derived from DXA data may provide a simple noninvasive methodology for assessing the risk of stress fracture.

Fatigue-type stress fractures of the lower limb associated with fibrous cortical defects/non-ossifying fibromas in the skeletally immature.

PubMed

Shimal, A; Davies, A M; James, S L J; Grimer, R J

2010-05-01

To investigate the association of a fatigue-type stress fracture and a fibrous cortical defect/non-ossifying fibroma (FCD/NOF) of the lower limb long bones in skeletally immature patients. The patient database of a specialist orthopaedic oncology centre was searched to determine the number of skeletally immature patients (stress fracture. The diagnosis was established by a combination of typical imaging findings of a fatigue-type stress fracture, the absence of aggressive features suggestive of a sarcoma (e.g., interrupted periosteal reaction, cortical breach, and a soft-tissue mass) together with evidence of consolidation or healing on follow-up radiographs and resolution of symptoms over the subsequent weeks. The database was also used to determine the number of skeletally immature cases (stress fracture and a FCD or NOF) were reviewed. Six percent of patients (five cases) referred to an orthopaedic oncology unit, who were subsequently shown to have a stress fracture of the lower limb long bones, were found to have a related FCD/NOF. All had been referred with a suggested diagnosis of a bone sarcoma and/or osteomyelitis. The possibility of a stress fracture had been raised in only one case. Four cases involved the proximal tibia and one the distal femur. Radiographs revealed that both lesions arose in the posteromedial cortex in all but one of the cases. The radiographs and magnetic resonance imaging (MRI) features were considered typical of the overlapping pathological features of the lesions. A sarcoma could be effectively excluded in the absence of true

Association of stressful life events with accelerated bone loss in older men: the Osteoporotic Fractures in Men (MrOS) Study

PubMed Central

Fink, Howard A.; Kuskowski, Michael A.; Cauley, Jane A.; Taylor, Brent C.; Schousboe, John T.; Cawthon, Peggy M.; Ensrud, Kristine E.

2015-01-01

Purpose/Introduction Prior studies suggest that stressful life events may increase adverse health outcomes, including falls and possibly fractures. The current study builds on these findings and examines whether stressful life events are associated with increased bone loss. Methods 4388 men aged ≥65 years in the Osteoporotic Fractures in Men study completed total hip bone mineral density (BMD) measures at baseline and visit 2, approximately 4.6 years later, and self-reported stressful life events data mid-way between baseline and visit 2, and at visit 2. We used linear regression to model the association of stressful life events with concurrent annualized total hip BMD loss, and log binomial regression or Poisson regression to model risk of concurrent accelerated BMD loss (>1 SD more than mean annualized change). Results 75.3% of men reported ≥1 type of stressful life event, including 43.3% with ≥2 types of stressful life events. Mean annualized BMD loss was −0.36% (SD 0.88) and 13.9% of men were categorized with accelerated BMD loss (about 5.7% or more total loss). Rate of annualized BMD loss increased with the number of types of stressful life events after adjustment for age (p<0.001), but not after multivariable adjustment (p=0.07). Multivariable-adjusted risk of accelerated BMD loss increased with the number of types of stressful life events (RR, 1.10 [95% CI, 1.04–1.16]) per increase of 1 type of stressful life event). Fracture risk was not significantly different between stressful life event-accelerated bone loss subgroups (p=0.08). Conclusions In these older men, stressful life events were associated with a small, dose-related increase in risk of concurrent accelerated hip bone loss. Low frequency of fractures limited assessment of whether rapid bone loss mediates any association of stressful life events with incident fractures. Future studies are needed to confirm these findings and to investigate the mechanism that may underlie this association

A retrospective cohort study on the influence of UV index and race/ethnicity on risk of stress and lower limb fractures

PubMed Central

2013-01-01

Background Low vitamin D status increases the risk of stress fractures. As ultraviolet (UV) light is required for vitamin D synthesis, low UV light availability is thought to increase the risk of vitamin D insufficiency and poor bone health. The purpose of this investigation was to determine if individuals with low UV intensity at their home of record (HOR) or those with darker complexions are at increased risk of developing stress fractures and lower limb fractures during U.S. Army Basic Combat Training (BCT). Methods This was a retrospective cohort study using the Armed Forces Health Surveillance Center data repository. All Basic trainees were identified from January 1997 to January 2007. Cases were recruits diagnosed with stress fractures and lower limb fractures during BCT. The recruit’s home of record (HOR) was identified from the Defense Manpower Data Center database. The average annual UV intensity at the recruits’ HOR was determined using a U.S National Weather Service database and recruits were stratified into low (≤3.9); moderate (4.0-5.4), and high (≥5.5) UV index regions. Race was determined from self-reports. Results The dataset had 421,461 men and 90,141women. Compared to men, women had greater risk of developing stress fractures (odds ratio (OR) = 4.5, 95% confidence interval (95%CI) = 4.4-4.7, p < 0.01). Contrary to the hypothesized effect, male and female recruits from low UV index areas had a slightly lower risk of stress fractures (male OR (low UV/high UV) = 0.92, 95%CI = 0.87-0.97; females OR = 0.89, 95%CI = 0.84-0.95, p < 0.01) and were at similar risk for lower limb fractures (male OR = 0.98, 95%CI = 0.89-1.07; female OR = 0.93, 95%CI = 0.80-1.09) than recruits from high UV index areas. Blacks had lower risk of stress and lower limb fractures than non-blacks, and there was no indication that Blacks from low UV areas were at increased risk for bone injuries. Conclusions The UV index at

A retrospective cohort study on the influence of UV index and race/ethnicity on risk of stress and lower limb fractures.

PubMed

Montain, Scott J; McGraw, Susan M; Ely, Matthew R; Grier, Tyson L; Knapik, Joseph J

2013-04-12

Low vitamin D status increases the risk of stress fractures. As ultraviolet (UV) light is required for vitamin D synthesis, low UV light availability is thought to increase the risk of vitamin D insufficiency and poor bone health. The purpose of this investigation was to determine if individuals with low UV intensity at their home of record (HOR) or those with darker complexions are at increased risk of developing stress fractures and lower limb fractures during U.S. Army Basic Combat Training (BCT). This was a retrospective cohort study using the Armed Forces Health Surveillance Center data repository. All Basic trainees were identified from January 1997 to January 2007. Cases were recruits diagnosed with stress fractures and lower limb fractures during BCT. The recruit's home of record (HOR) was identified from the Defense Manpower Data Center database. The average annual UV intensity at the recruits' HOR was determined using a U.S National Weather Service database and recruits were stratified into low (≤3.9); moderate (4.0-5.4), and high (≥5.5) UV index regions. Race was determined from self-reports. The dataset had 421,461 men and 90,141 women. Compared to men, women had greater risk of developing stress fractures (odds ratio (OR) = 4.5, 95% confidence interval (95%CI) = 4.4-4.7, p < 0.01). Contrary to the hypothesized effect, male and female recruits from low UV index areas had a slightly lower risk of stress fractures (male OR (low UV/high UV) = 0.92, 95%CI = 0.87-0.97; females OR = 0.89, 95%CI = 0.84-0.95, p < 0.01) and were at similar risk for lower limb fractures (male OR = 0.98, 95%CI = 0.89-1.07; female OR = 0.93, 95%CI = 0.80-1.09) than recruits from high UV index areas. Blacks had lower risk of stress and lower limb fractures than non-blacks, and there was no indication that Blacks from low UV areas were at increased risk for bone injuries. The UV index at home of record is not associated with stress

Are Elite Female Soccer Athletes at Risk for Disordered Eating Attitudes, Menstrual Dysfunction, and Stress Fractures?

PubMed

Prather, Heidi; Hunt, Devyani; McKeon, Kathryn; Simpson, Scott; Meyer, E Blair; Yemm, Ted; Brophy, Robert

2016-03-01

To determine the prevalence of stress fractures, menstrual dysfunction and disordered eating attitudes in elite female soccer athletes. Cross-sectional descriptive study. Female soccer athletes were recruited from a national level youth soccer club, an NCAA Division I university team, and a women's professional team. Two hundred twenty female soccer athletes with a mean age of 16.4 ± 4 years and BMI of 20.8 ± 2 kg/m(2) completed the study, representing all athletes from the included teams. One-time surveys completed by the athletes. Height and weight were recorded, and body mass index (BMI) was calculated for each athlete. Athletes reported age of menarche, history of missing 3 or more menses within a 12-month period and stress fracture. The Eating Attitudes Test (EAT-26) was used to assess the athlete's body perception and attitudes toward eating. Of the 220 soccer athletes, 3 athletes (1.6%) had a low BMI for their age, and 19 (8.6%) reported stress fractures of the lower extremity. Among athletes who had reached menarche, the average onset was 13 + 1 year; menstrual dysfunction were present in 21 (19.3%). On the EAT-26, 1 player scored in the high risk range (>20) and 17 (7.7%) scored in the intermediate risk range (10-19) for eating disorders. Athletes with an EAT-26 score ≥ 10 points had a significantly higher prevalence of menstrual dysfunction in the past year compared to athletes with an EAT-26 score of less than 10 (P = .02). Elite female soccer athletes are susceptible to stress fractures and menstrual dysfunction and have delayed onset of menarche despite normal BMI and appropriate body perception and attitudes towards eating. Further studies are needed to better understand stress fracture risk in female soccer athletes and in other team sports to determine how these findings relate to long-term bone health in this population. Copyright © 2016. Published by Elsevier Inc.

Fracture mechanics correlation of boron/aluminum coupons containing stress risers

NASA Technical Reports Server (NTRS)

Adsit, N. R.; Waszczak, J. P.

1975-01-01

The mechanical behavior of boron/aluminum near stress risers has been studied and reported. This effort was directed toward defining the tensile behavior of both unidirectional and (0/ plus or minus 45) boron/aluminum using linear elastic fracture mechanics (LEFM). The material used was 5.6-mil boron in 6061 aluminum, consolidated using conventional diffusion bonding techniques. Mechanical properties are reported for both unidirectional and (0/ plus or minus 45) boron/aluminum, which serve as control data for the fracture mechanics predictions. Three different flawed specimen types were studied. In each case the series of specimens remained geometrically similar to eliminate variations in finite size correction factors. The fracture data from these tests were reduced using two techniques. They both used conventional LEFM methods, but the existence of a characteristic flaw was assumed in one case and not the other. Both the data and the physical behavior of the specimens support the characteristic flaw hypothesis. Cracks were observed growing slowly in the (0/ plus or minus 45) laminates, until a critical crack length was reached at which time catastrophic failure occurred.

Effect of surgical approach on physical activity and pain control after sacral colpopexy.

PubMed

Collins, Sarah A; Tulikangas, Paul K; O'Sullivan, David M

2012-05-01

We sought to compare recovery of activity and pain control after robotic (ROB) vs abdominal (ABD) sacral colpopexy. Women undergoing ROB and ABD sacral colpopexy wore accelerometers for 7 days preoperatively and the first 10 days postoperatively. They completed postoperative pain diaries and Short Form-36 questionnaires before and after surgery. At 5 days postoperatively, none of the 14 subjects in the ABD group and 4 of 28 (14.3%) in the ROB group achieved 50% total baseline activity counts (P = .283). At 10 days, 5 of 14 (35.7%) in the ABD group and 8 of 26 (30.8%) in the ROB group (P = .972) achieved 50%. Postoperative pain was similar in both groups. Short Form-36 vitality scores were lower (P = .017) after surgery in the ABD group, but not in the ROB group. Women undergoing ROB vs ABD sacral colpopexy do not recover physical activity faster, and pain control is not improved. Copyright © 2012 Mosby, Inc. All rights reserved.

Adhesive arachnoiditis after percutaneous fibrin glue treatment of a sacral meningeal cyst.

PubMed

Hayashi, Kazunori; Nagano, Junji; Hattori, Satoshi

2014-06-01

The authors present the case of a 64-year-old woman who was referred for severe sacral pain. She reported that her pain had been longstanding, and had greatly increased after percutaneous fibrin glue placement therapy for a sacral meningeal cyst 2 months earlier at a different hospital. An MRI scan obtained immediately after fibrin glue placement at that hospital suggested that fibrin glue had migrated superiorly into the subarachnoid space from the sacral cyst to the level of L-4. On admission to the authors' institution, physical examination demonstrated no abnormal findings except for perianal hypesthesia. An MRI study obtained at admission demonstrated a cystic lesion in the peridural space from the level of S-2 to S-4. Inhomogeneous intensity was identified in this region on T2-weighted images. Because the cauda equina and nerve roots appeared to be compressed by the lesion, total cyst excision was performed. The cyst cavity was filled with fluid that resembled CSF, plus gelatinous material. Histopathological examination revealed that the cyst wall was composed of hyaline connective tissue with some calcification. No nervous tissue or ganglion cells were found in the tissue. The gelatinous material was acellular, and appeared to be degenerated fibrin glue. Sacral pain persisted to some extent after surgery. The authors presumed that migrated fibrin glue caused the development of adhesive arachnoiditis. The risk of adhesive arachnoiditis should be considered when this therapy is planned. Communication between a cyst and the subarachnoid space should be confirmed to be sufficiently narrow to prevent the migration of injected fibrin glue.

Use of Sacral Nerve Stimulation for the Treatment of Overlapping Constipation and Fecal Incontinence

PubMed Central

Sreepati, Gouri; James-Stevenson, Toyia

2017-01-01

Patient: Female, 51 Final Diagnosis: Fecal incontinence Symptoms: Constipation • fecal incontinence Medication: — Clinical Procedure: Sacral nerve stimulator Specialty: Gastroenterology and Hepatology Objective: Rare co-existance of disease or pathology Background: Fecal incontinence and constipation are common gastrointestinal complaints, but rarely occur concurrently. Management of these seemingly paradoxical processes is challenging, as treatment of one symptom may exacerbate the other. Case Report: A 51-year-old female with lifelong neurogenic bladder secondary to spina bifida occulta presented with progressive symptoms of daily urge fecal incontinence as well as hard bowel movements associated with straining and a sensation of incomplete evacuation requiring manual disimpaction. Pelvic floor testing showed poor ability to squeeze the anal sphincter, which indicated sphincter weakness as a major contributor to her fecal incontinence symptoms. Additionally, on defecography she was unable to widen her posterior anorectal angle or relax the anal sphincter during defecation consistent with dyssynergic defecation. A sacral nerve stimulator was placed for management of her fecal incontinence. Interestingly, her constipation also dramatically improved with sacral neuromodulation. Conclusions: This unique case highlights the emerging role of sacral nerve stimulation in the treatment of complex pelvic floor dysfunction with improvement in symptoms beyond fecal incontinence in a patient with dyssynergic-type constipation. PMID:28265107

Imaging of upper extremity stress fractures in the athlete.

PubMed

Anderson, Mark W

2006-07-01

Although it is much less common than injuries in the lower extremities, an upper extremity stress injury can have a significant impact on an athlete. If an accurate and timely diagnosis is to be made, the clinician must have a high index of suspicion of a stress fracture in any athlete who is involved in a throwing, weightlifting, or upper extremity weight-bearing sport and presents with chronic pain in the upper extremity. Imaging should play an integral role in the work-up of these patients; if initial radiographs are unrevealing, further cross-sectional imaging should be strongly considered. Although a three-phase bone scan is highly sensitive in this regard, MRI has become the study of choice at most centers.

Femoral neck stress fracture in a female athlete: a case report

PubMed Central

Avrahami, Daniel; Pajaczkowski, Jason A.

2012-01-01

Objective The purpose of this case report is to describe chiropractic rehabilitation of a master's-level athlete with proximal femoral stress fracture and provide a brief discussion of stress fracture pathology. Clinical Features A 41-year-old female master's-level endurance athlete presented with chronic groin pain later diagnosed and confirmed by magnetic resonance imaging as a stress fracture of the femoral neck. After diagnosis, the patient was referred to a doctor of chiropractic at week 1 of the non–weight-bearing physical rehabilitation process. At that time, the patient presented with sharp and constant groin pain rated 6/10 on a numeric rating scale. Intervention and Outcome This patient avoided weight-bearing activity for 8 weeks while cross-training and was able to return to her sport after this period. The patient was progressed through a series of non–weight-bearing strengthening exercises for the lower extremity. Myofascial release therapy was performed on the gluteal, hip flexor, and groin muscle groups to improve range of motion. Motion palpation testing the lumbar and sacroiliac joints was performed during each session, and manipulative therapy was performed when necessary. The patient was seen once a week for 8 weeks. Reevaluation was performed at week 8; at that time, the patient reported no groin pain (0/10). The patient was discharged from care and referred back to the supervising physician for clearance to return to sporting activities. One month after discharge, she reported that she was pain free and had fully returned to sport activities. Conclusion This case report demonstrates the importance of a through clinical history, physical examination, and magnetic resonance imaging in the accurate diagnosis of a patient with chronic groin pain and that chiropractic care can contribute to rehabilitation programs for these injuries. PMID:23843760

Fracture Mechanisms For SiC Fibers And SiC/SiC Composites Under Stress-Rupture Conditions at High Temperatures

NASA Technical Reports Server (NTRS)

DiCarlo, James A.; Yun, Hee Mann; Hurst, Janet B.; Viterna, L. (Technical Monitor)

2002-01-01

The successful application of SiC/SiC ceramic matrix composites as high-temperature structural materials depends strongly on maximizing the fracture or rupture life of the load-bearing fiber and matrix constituents. Using high-temperature data measured under stress-rupture test conditions, this study examines in a mechanistic manner the effects of various intrinsic and extrinsic factors on the creep and fracture behavior of a variety of SiC fiber types. It is shown that although some fiber types fracture during a large primary creep stage, the fiber creep rate just prior to fracture plays a key role in determining fiber rupture time (Monkman-Grant theory). If it is assumed that SiC matrices rupture in a similar manner as fibers with the same microstructures, one can develop simple mechanistic models to analyze and optimize the stress-rupture behavior of SiC/SiC composites for applied stresses that are initially below matrix cracking.

Compression Fracture of CFRP Laminates Containing Stress Intensifications.

PubMed

Leopold, Christian; Schütt, Martin; Liebig, Wilfried V; Philipkowski, Timo; Kürten, Jonas; Schulte, Karl; Fiedler, Bodo

2017-09-05

For brittle fracture behaviour of carbon fibre reinforced plastics (CFRP) under compression, several approaches exist, which describe different mechanisms during failure, especially at stress intensifications. The failure process is not only initiated by the buckling fibres, but a shear driven fibre compressive failure beneficiaries or initiates the formation of fibres into a kink-band. Starting from this kink-band further damage can be detected, which leads to the final failure. The subject of this work is an experimental investigation on the influence of ply thickness and stacking sequence in quasi-isotropic CFRP laminates containing stress intensifications under compression loading. Different effects that influence the compression failure and the role the stacking sequence has on damage development and the resulting compressive strength are identified and discussed. The influence of stress intensifications is investigated in detail at a hole in open hole compression (OHC) tests. A proposed interrupted test approach allows identifying the mechanisms of damage initiation and propagation from the free edge of the hole by causing a distinct damage state and examine it at a precise instant of time during fracture process. Compression after impact (CAI) tests are executed in order to compare the OHC results to a different type of stress intensifications. Unnotched compression tests are carried out for comparison as a reference. With this approach, a more detailed description of the failure mechanisms during the sudden compression failure of CFRP is achieved. By microscopic examination of single plies from various specimens, the different effects that influence the compression failure are identified. First damage of fibres occurs always in 0°-ply. Fibre shear failure leads to local microbuckling and the formation and growth of a kink-band as final failure mechanisms. The formation of a kink-band and finally steady state kinking is shifted to higher compressive strains

Compression Fracture of CFRP Laminates Containing Stress Intensifications

PubMed Central

Schütt, Martin; Philipkowski, Timo; Kürten, Jonas; Schulte, Karl

2017-01-01

For brittle fracture behaviour of carbon fibre reinforced plastics (CFRP) under compression, several approaches exist, which describe different mechanisms during failure, especially at stress intensifications. The failure process is not only initiated by the buckling fibres, but a shear driven fibre compressive failure beneficiaries or initiates the formation of fibres into a kink-band. Starting from this kink-band further damage can be detected, which leads to the final failure. The subject of this work is an experimental investigation on the influence of ply thickness and stacking sequence in quasi-isotropic CFRP laminates containing stress intensifications under compression loading. Different effects that influence the compression failure and the role the stacking sequence has on damage development and the resulting compressive strength are identified and discussed. The influence of stress intensifications is investigated in detail at a hole in open hole compression (OHC) tests. A proposed interrupted test approach allows identifying the mechanisms of damage initiation and propagation from the free edge of the hole by causing a distinct damage state and examine it at a precise instant of time during fracture process. Compression after impact (CAI) tests are executed in order to compare the OHC results to a different type of stress intensifications. Unnotched compression tests are carried out for comparison as a reference. With this approach, a more detailed description of the failure mechanisms during the sudden compression failure of CFRP is achieved. By microscopic examination of single plies from various specimens, the different effects that influence the compression failure are identified. First damage of fibres occurs always in 0°-ply. Fibre shear failure leads to local microbuckling and the formation and growth of a kink-band as final failure mechanisms. The formation of a kink-band and finally steady state kinking is shifted to higher compressive strains

[Effect of axial stress stimulation on tibial and fibular open fractures healing after Taylor space stent fixation].

PubMed

Ge, Qihang; Wan, Chunyou; Liu, Yabei; Ji, Xu; Ma, Jihai; Cao, Haikun; Yong, Wei; Liu, Zhao; Zhang, Ningning

2017-08-01

To investigate the effect of axial stress stimulation on tibial and fibular open fractures healing after Taylor space stent fixation. The data of 45 cases with tibial and fibular open fractures treated by Taylor space stent fixation who meet the selection criteria between January 2015 and June 2016 were retrospectively analysed. The patients were divided into trial group (23 cases) and control group (22 cases) according to whether the axial stress stimulation was performed after operation. There was no significant difference in gender, age, affected side, cause of injury, type of fracture, and interval time from injury to operation between 2 groups ( P >0.05). The axial stress stimulation was performed in trial group after operation. The axial load sharing ratio was tested, and when the value was less than 10%, the external fixator was removed. The fracture healing time, full weight-bearing time, and external fixator removal time were recorded and compared. After 6 months of external fixator removal, the function of the limb was assessed by Johner-Wruhs criteria for evaluation of final effectiveness of treatment of tibial shaft fractures. There were 2 and 3 cases of needle foreign body reaction in trial group and control group, respectively, and healed after symptomatic anti allergic treatment. All the patients were followed up 8-12 months with an average of 10 months. All the fractures reached clinical healing, no complication such as delayed union, nonunion, or osteomyelitis occurred. The fracture healing time, full weight-bearing time, and external fixator removal time in trial group were significantly shorter than those in control group ( P <0.05). After 6 months of external fixator removal, the function of the limb was excellent in 13 cases, good in 6 cases, fair in 3 cases, and poor in 1 case in trial group, with an excellent and good rate of 82.6%; and was excellent in 5 cases, good in 10 cases, fair in 4 cases, and poor in 3 cases in control group, with an

Role of intraoperative radiotherapy in the treatment of sacral chordoma.

PubMed

Jullien-Petrelli, Ariel Christian; García-Sabrido, J L; Orue-Echebarria, M I; Lozano, P; Álvarez, A; Serrano, J; Calvo, F M; Calvo-Haro, J A; Lasso, J M; Asencio, J M

2018-04-01

Sacral chordoma is a rare entity with high local recurrence rates when complete resection is not achieved. To date, there are no series available in literature combining surgery and intraoperative radiotherapy (IORT). The objective of this study was to report the experience of our center in the management of sacral chordoma combining radical resection with both external radiotherapy and IORT. This is a retrospective case series. The patient sample included 15 patients with sacral chordoma resected in our center from 1998 to 2015. The outcome measures were overall survival (OS), disease-free survival (DFS), and rates of local and distant recurrences. We retrospectively reviewed the records of all the patients with sacral chordoma resected in our center from 1998 to December 2015. Overall survival, DFS, and rates of local and distant recurrences were calculated. Results between patients treated with or without IORT were compared. A total of 15 patients were identified: 8 men and 7 women. The median age was 59 years (range 28-77). Intraoperative radiotherapy was applied in nine patients and six were treated with surgical resection without IORT. In 13 patients, we performed the treatment of the primary tumor, and in two patients, we performed the treatment of recurrence disease. A posterior approach was used in four patients. Wide surgical margins (zero residue) were achieved in six patients, marginal margins (microscopic residue) were achieved in seven patients, and there were no patients with intralesional (R2) margins. At a median follow-up of 38 months (range 11-209 months), the 5-year OS in the IORT group was 100% versus 53% in the group of non-IORT (p=.05). The median DFS in the IORT group was 85 months, and that in the non-IORT group was 41 months. In the group without IORT, two patients died and nobody died during the follow-up in the group treated with IORT. High-sacrectomy treated patients had a median survival of 41 months, and low-sacrectomy treated

Acute urinary retention attributable to sacral herpes zoster.

PubMed

Acheson, J; Mudd, D

2004-11-01

Acute urinary retention in women is uncommon. A 63 year old woman presented with suprapubic pain, a palpable bladder, and multiple grouped vesicles on the right buttock. Catheterisation showed a residual of 2000 ml. A case is reported of acute urinary retention secondary to herpes zoster infection of the sacral nerves (S2-4).

Penile fracture seems more likely during sex under stressful situations.

PubMed

Kramer, Andrew C

2011-12-01

The unusual event of penile fracture occurs when there is a disruption of the tunica albuginea surrounding engorged erectile tissue during aggressive sexual behavior. There is often an audible crack and rapid detumescence with subcutaneous hemorrhage that follows. Medical literature has described the etiology and treatment of penile fracture. We report the remarkably unusual social situations of a series of patients who sustained this unique injury. We conducted a retrospective chart review of 16 patients whose injury was severe enough to require surgical repair at the University of Maryland between 2007 and 2011. Particular attention was paid to the intake interview in the emergency department and the postoperative chart notes by the attending urologist to ascertain out-of-the-ordinary social situations in which the injury was sustained. The occurrence of penile fracture is sufficiently rare that the author was able to interact personally with most of the patients. The patients were remarkably forthcoming with the personal social dynamics of the sexual encounter. Half of these penile fracture patients sustained the injury during an extramarital affair. Only three patients sustained the injury in a bedroom; the remainder was in out-of-the-ordinary locations for sexual intercourse, e.g., cars, elevator, the workplace, and public restrooms. Penile fracture patients appear to be a unique population of men who are having sexual intercourse under stressful situations. Extramarital affairs and out-of-the-ordinary locations appear common in patients sustaining this relatively rare injury. © 2011 International Society for Sexual Medicine.

Subarachnoid and basal cistern navigation through the sacral hiatus with guide wire assistance.

PubMed

Layer, Lauren; Riascos, Roy; Firouzbakht, Farhood; Amole, Adewumi; Von Ritschl, Rudiger; Dipatre, Pier; Cuellar, Hugo

2011-07-01

Intraspinal navigation with catheters and fiberscopes has shown feasible results for diagnosis and treatment of intraspinal and intracranial lesions. The most common approach, lumbar puncture, has allowed access to the spinal cord, however, coming with the difficulties of fiberscope damage and decreased torque for guidance. Our objective in this study is to allow an alternate access, the sacral hiatus, with guide wire assistance into the subarachnoid and intracranial structures, while easing the angle of entry and increasing torque. We advanced catheters with guide wire and fluoroscopy assistance into the sacral hiatus of three cadavers. After entry, the thecal sac was punctured and the catheter with guide wire was advanced rostrally until positioned in the basal cisterns of the brain. We confirmed catheter placement with contrast injection, autopsy, and dissection. In our study, the sacral hiatus was easily accessed, but resistance was found when attempting to puncture the thecal sac. The advancement of the catheter with guide wire assistance glided easily rostrally until some mild resistance was discovered at entry into the foramen magnum. With redirection, all catheters passed with ease into the basal cisterns. Positioning was confirmed with contrast injection with fluoroscopy evidence, autopsy, and dissection. There was no macroscopic or microscopic evidence of damage to the spinal roots, spinal cord, or cranial nerves. The sacral hiatus with guide wire assistance is an accessible conduit for uncomplicated entry into the subarachnoid and basal cistern space without damaging surrounding structures.