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Background: Developed in recent years, CrossFit has gained much popularity in the industrialized world due to various advantages such as scalability, availability and high sense of community. Nonetheless, with growing interest, reports on associated injury have also emerged, highlighting the need for better characterization and analysis of specific risk factors. Our goal was therefore to characterize injuries related to CrossFit and to describe specific risk factors associated with their occurrence., Methods: We conducted a cross-sectional study by using a questionnaire aimed at CrossFit athletes responding to personally delivered questionnaires nationwide., Results: A total of 502 fully answered our questionnaire. Athletes who reported injury had a slightly higher mean weight (P=0.065) and Body Mass Index (P=0.059) compared to their non-injured counterparts and the most affected area was the upper extremity (N.=133, 26.4%) followed by the shoulder (N.=101, 20.1%). Athletes who performed preworkout warmup exercises were significantly more prone to report an injury (P=0.007) as well as those who had prior injury in the affected area. Backward stepwise regression model assessing injury predictors revealed that preworkout warmup (OR 1.816; 95% CI 1.095-3.011; P=0.021) and preinjury local pain (OR 1.554; 95% CI 1.004-2.046; P=0.048) in CrossFit athletes were significant predictors of injuries., Conclusions: Pretraining warm-ups and preinjury localized pain were found to predict significant injury among CrossFit athletes.

Background: Acute upper airway compromise is a rare but catastrophic complication after anterior cervical discectomy and fusion. This study aims to develop a score to identify patients at risk of acute postoperative airway compromise (PAC)., Methods: Potential risk factors for acute PAC were selected by a modified Delphi process. Ten patients with acute PAC were identified of 1466 patients who underwent elective anterior cervical discectomy and fusion between July 2014 and May 2019. A comparison group was created by a randomized selection process (non-PAC group). Factors associated with PAC and a P value of < 0.10 were entered into a logistic regression model and coefficients contributed to each risk factor's overall score. Calibration of the model was evaluated using the Hosmer-Lemeshow goodness-of-fit test. Quantitative discrimination was calculated, and the final model was internally validated with bootstrap sampling., Results: We identified 18 potential risk factors from our Delphi process, of which 6 factors demonstrated a significant association with airway compromise: age >65 years, current smoking status, American Society of Anesthesiologists class >2, history of a bleeding disorder, surgery of upper subaxial cervical spine (above C4), and duration of surgery >179 minutes. The final prediction model included 5 predictors with very strong performance characteristics. These 5 factors formed the PAC score, with a range from 0 to 100. A score of 20 yielded the greatest balance of sensitivity (80%) and specificity (88%)., Conclusions: The acute PAC score demonstrates strong performance characteristics. The PAC score might help identify patients at risk of upper airway compromise caused by surgical site abnormalities., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Study Design: A large-scale retrospective case-control study., Objective: Examine diabetes as a risk factor for lumbar spinal stenosis (LSS) development and evaluate the impact of diabetes duration, glycemic control, and associated complications on this risk., Summary of Background Data: Diabetes mellitus, a multiorgan disorder impacting various connective tissues, induces histological changes in spinal structures, particularly the ligamentum flavum. While clinical studies suggest a higher incidence of LSS in diabetic patients, substantial epidemiological research on the likelihood of LSS diagnosis in individuals with diabetes is scarce., Materials and Methods: Using nationwide data, a total of 49,576 patients diagnosed with LSS based on International Classification of Diseases-10 codes were matched with controls of the same number based on age and sex. Employing a multivariable logistic regression model, the study assessed for the association between spinal stenosis and diabetes, while adjusting for confounders., Results: We found a higher likelihood of LSS diagnosis in diabetic patients [odds ratio (OR) 1.39, 95% CI: 1.36 - 1.43, P <0.001]. Those with hemoglobin A1c ≥7% and ≥1 diabetes-related complication also had an elevated likelihood (OR: 1.19, 95% CI: 1.08-1.31, P =0.001). Prolonged diabetes exposure increased the risk. Diabetes diagnosis reduced median survival by around 4.5 years for both stenosis and nonstenosis patients; spinal stenosis diagnosis alone minimally impacted survival. Relative to individuals diagnosed with diabetes mellitus at the age of 65 or older, the OR for developing LSS were 1.22 (95% CI: 1.18-1.27, P <0.001) when DM was diagnosed at 50 to 65 years old and 1.67 (95% CI: 1.56-1.79, P <0.001) for those under 50 years old. Multivariate analysis revealed a significantly increased risk of all-cause mortality in patients with DM and spinal stenosis (hazard ratio: 1.36, 95% CI: 1.29-1.44, P <0.001) and those with DM without stenosis (hazard ratio: 1.49, 95% CI: 1.41-1.57, P <0.001) compared with controls., Conclusions: Diabetic patients with prolonged disease, poor glycemic control, and diabetes-related complications face an elevated risk of developing LSS. Recognizing the reciprocal adverse relationship between these conditions is crucial in clinical practice and designing public health measures for managing both conditions., Level of Evidence: 4., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

By translating mechanical forces into molecular signals, proprioceptive neurons provide the CNS with information on muscle length and tension, which is necessary to control posture and movement. However, the identities of the molecular players that mediate proprioceptive sensing are largely unknown. Here, we confirm the expression of the mechanosensitive ion channel ASIC2 in proprioceptive sensory neurons. By combining in vivo proprioception-related functional tests with ex vivo electrophysiological analyses of muscle spindles, we showed that mice lacking Asic2 display impairments in muscle spindle responses to stretch and motor coordination tasks. Finally, analysis of skeletons of Asic2 loss-of-function mice revealed a specific effect on spinal alignment. Overall, we identify ASIC2 as a key component in proprioceptive sensing and a regulator of spine alignment., (© 2023 The Authors. Experimental Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)

Study Design: Retrospective case series analysis., Objective: To identify relevant clinical and radiographic markers for patients presenting with infectious spondylo-discitis associated with spinal instability directly related to the infectious process., Methods: We evaluated patients presenting with de-novo intervertebral discitis or vertebral osteomyelitis /discitis (VOD) who initiated non-surgical treatment. Patients who failed conservative treatment and required stabilization surgery within 90 days were defined as " failed treatment group" (FTG) . Patients who experienced an uneventful course served as controls and were labeled as " nonsurgical group" (NSG). A wide array of baseline clinical and radiographic parameters was retrieved and compared between 2 groups., Results: Overall 35 patients had initiated non-surgical treatment for VOD. 25 patients had an uneventful course (NSG), while 10 patients failed conservative treatment ("FTG") within 90 days. Factors found to be associated with poorer outcome were intra-venous drug abuse (IVDA) as well as the presence of fever upon initial presentation. Radiographically, involvement of the same-level facets and the extent of caudal and rostral VB involvement in both MRI and CT were found to be significantly associated with poorer clinical and radiographic outcome., Conclusions: We show that clinical factors such as IVDA status and fever as well as the extent of osseous and posterior element involvement may prove to be helpful in favoring surgical treatment early on in the management of spinal infections.

Introduction : Anticoagulation use in the elderly is common for patients undergoing femoral neck hip surgery. However, its use presents a challenge to balance it with associated comorbidities and benefits for the patients. As such, we attempted to compare the risk factors, perioperative outcomes, and postoperative outcomes of patients who used warfarin preoperatively and patients who used therapeutic enoxaparin. Methods : From 2003 through 2014, we queried our database to determine the cohorts of patients who used warfarin preoperatively and the patients who used therapeutic enoxaparin. Risk factors included age, gender, Body Mass Index (BMI) > 30, Atrial Fibrillation (AF), Chronic Heart Failure (CHF), and Chronic Renal Failure (CRF). Postoperative outcomes were also collected at each of the patients' follow-up visits, including number of hospitalization days, delays to theatre, and mortality rate. Results : The minimum follow-up was 24 months and the average follow-up was 39 months (range: 24-60 months). In the warfarin cohort, there were 140 patients and 2055 patients in the therapeutic enoxaparin cohort. Number of hospitalization days (8.7 vs. 9.8, p = 0.02), mortality rate (58.7% vs. 71.4%, p = 0.003), and delays to theatre (1.70 vs. 2.86, p < 0.0001) were significantly longer for the anticoagulant cohort than the therapeutic enoxaparin cohort. Warfarin use best predicted number of hospitalization days ( p = 0.00) and delays to theatre ( p = 0.01), while CHF was the best predictor of mortality rate ( p = 0.00). Postoperative complications, such as Pulmonary Embolism (PE) ( p = 0.90), Deep Vein Thrombosis (DVT) ( p = 0.31), and Cerebrovascular Accidents (CVA) ( p = 0.72), pain levels ( p = 0.95), full weight-bearing status ( p = 0.08), and rehabilitation use ( p = 0.34) were similar between the cohorts. Conclusion: Warfarin use is associated with increased number of hospitalization days and delays to theatre, but does not affect the postoperative outcome, including DVT, CVA, and pain levels compared to therapeutic enoxaparin use. Warfarin use proved to be the best predictor of hospitalization days and delays to theatre while CHF predicted mortality rate.

Study Design: Case-Control Study., Objective: The purpose of this retrospective study is to evaluate risk factors for developing a postoperative ileus after posterior spine surgery., Methods: Patient charts, including radiographs were evaluated retrospectively. Diagnosis of an ileus was confirmed radiographically by a CT scan in all cases. The control group was retrieved by selecting a random sample of patients undergoing posterior spine surgery who did not develop bowel dysfunction postoperatively., Results: A total of 40 patients had a postoperative ileus. The control group consisted of 80 patients. Both groups did not differ significantly in age, gender, BMI, tobacco use, comorbidities or status of previous abdominal surgery. Significant differences between the 2 groups was the length of stay (5.9 vs. 11.2; p = 0.001), surgery in the lumbar spine (47.5% vs. 87.5%; p < 0.001) and major spine surgery involving > 3 levels (35.0% vs. 57.5%; p = 0.019). Patients who suffered from an ileus were more likely to be treated in ICU (23.8% vs. 37.5%; p = 0.115), being re-admitted (0.0% vs 5.0%; p = 0.044) and having a delayed discharge (32.5% vs. 57.5%; p = 0.009). Multivariable analysis demonstrated that lumbar spine surgery compared to thoracic and/or cervical spine surgery (p = 0.00, OR 8.7 CI 2.9-25.4) and major spine surgery involving > 3 levels (p = 0.012; OR 3.0, CI 1.3-7.2) are associated with developing an ileus postoperatively., Conclusion: Surgeries of the lumbar spine as well as those involving > 3 levels are associated with developing a postoperative ileus. Further studies are needed to expand on possible risk factors and to better understand the mechanism underlying postoperative ileus in spine surgery patients.

Study Design: A retrospective study., Objective: To describe the modified iliac screw (mILS) technique and compare it to other spinopelvic fixation techniques in terms of wound healing complications, hardware prominence, and failure., Summary of Background Data: The traditional entry point of an iliac screw often causes postoperative gluteal pain from the prominent screw head. The use of an offset connector also adds a point of weakness to the construct. By choosing a different screw entry point offset connectors can be avoided, and the screw head itself is less prominent, thereby reducing postoperative discomfort., Materials and Methods: A retrospective analysis was performed of adult patients undergoing lumbopelvic fixation (LPF) between January 2014 and June 2019. Patients were grouped into 1 of 3 groups based on the technique of pelvic fixation: S2 alar-iliac (S2AI) screw, traditional iliac screw (tILS), and mILS. The primary outcome parameter was the minimal distance from screw head to skin. Secondary outcome parameters were instrumentation loosening/failure, adjacent level fractures, pseudoarthrosis, and medial or lateral iliac screw perforation., Results: A total of 190 patients undergoing LPF were included in the following 3 groups: mILS group (n=113), tILS group (n=40), and S2AI group (n=37). The mean minimal distance from screw head to skin in the mILS group was 31.3 mm compared with 23.7 mm in the tILS group (P<0.00199). No statistically significant differences were found when comparing the 3 groups with respect to complications. The mILS group did not show any cases of prominent instrumentation and had the lowest rate of instrumentation failure., Conclusions: The mILS technique is an acceptable alternative for LPF, offering the benefits of iliac screw fixation while avoiding offset connectors and screw prominence complications associated with tILS., Level of Evidence: Level III., Competing Interests: The authors declare no conflict of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

In 1820, a young soldier was accidentally injured by a splinter of a fencing sword that penetrated through the right orbit into the brain. Examination by the French military surgeon Baron D.-J. Larrey revealed nominal aphasia, right hemiplegia, and monocular temporal hemianopia with an altitudinal component in the right eye only. In this paper, we aimed to reconstruct Larrey's contribution to neurology in the eve of correlative neuroanatomy. Larrey predicted that the blade passed from the roof of the right orbit to graze the root of the right optic nerve at the chiasm and from there, into the vicinity of the left Sylvian fissure. This course was verified posthumously 3 months later. Larrey's previous experience with galvanic currents enabled the adoption of Samuel von Sömmering's idea of regarding the brain as a telegraphing system made of a multitude of galvanic piles sending and receiving messages from distant points. Larrey's description is a very early diligent study of the tracks of penetrating head injuries. It correlates the symptoms with the injured cerebral tissues together with autopsy verification. Here are the beginnings of the construction of human correlative neuroanatomy, which lingered until flourishing in the first decades of the 20th century., (© 2022 The Author(s). Published by S. Karger AG, Basel.)

Objective: The purpose of this retrospective cohort study was to analyze the early complications and mortality associated with multilevel spine surgery for unstable fractures in patients older than 80 years of age with ankylosing spondylitis and to compare the results with an age- and sex-matched cohort of patients with unstable osteoporotic fractures., Methods: A retrospective review of the electronic medical records at a single institution was conducted between January 2014 and December 2019. Patient demographics, surgical characteristics, complications, hospital course, and 90-day mortality were collected. Comorbidities were stratified using the age-adjusted Charlson Comorbidity Index (CCI)., Results: Among 11,361 surgically treated patients, 22 patients with ankylosing spondylitis (AS group) and 24 patients with osteoporosis (OS group) were identified. The mean ages were 83.1 ± 3.1 years and 83.2 ± 2.6 years, respectively. A significant difference in the mean CCI score was found (7.6 vs 5.6; p < 0.001). Multilevel posterior fusion procedures were conducted in all patients, with 6.7 ± 1.4 fused levels in the AS group and 7.1 ± 1.1 levels fused in the OS group (p > 0.05). Major complications developed in 10 patients (45%) in the AS group compared with 4 patients (17%) in the OS group (p < 0.05). The 90-day mortality was 36% in the AS group compared with 0% in the OS group (p < 0.001)., Conclusions: Patients older than 80 years of age with AS bear a high risk of adverse events after multilevel spinal fusion procedures. The high morbidity and 90-day mortality should be clearly discussed and carefully weighed against surgical treatment.

Background: The design is a retrospective cohort study. Charcot spinal arthropathy (CSA) is a rare and poorly understood progressive destructive spine condition that usually affects patients with preexisting spinal cord injury. The complexity of this condition, especially when additionally burdened by superimposed infection in the CSA zone, can potentially lead to suboptimal management such as protracted antibiotic therapy, predisposition to hardware failure, and pseudarthrosis. While in noninfected CSA primary stabilization is the major goal, staged surgical management has not been stratified based upon presence of a superinfected CSA. We compare clinical and radiological outcomes of surgical treatment in CSA patients with and without concurrent spinal infections., Methods: Our single-institution database was reviewed for all patients diagnosed with CSA and surgically treated, who were subsequently divided into 2 cohorts: spinal arthropathy with superimposed infection and those without. Those were comparatively studied for complications and reoperation rate., Results: Fifteen patients with CSA underwent surgical intervention; mean follow up of 15.3 months (range, 0-43). Eleven patients received stabilization with a quadruple-rod thoracolumbopelvic construct, while 4 patients with superinfected CSA underwent a staged procedure. Patients treated with a staged approach experienced fewer intraoperative complications (0% versus 18%) and fewer revision surgeries (25% versus 36%). Both cohorts had the same eventual healing., Conclusions: Surgical management in CSA patients with primary emphasis on stability and modified surgical treatment based on presence of an active infection in the zone of neuropathic destruction will lead to similar eventual successful results with relatively few and manageable complications in this challenging patient population., Level of Evidence: 4., Clinical Relevance: The proposed treatment algorithm including the use of a quadruple-rod construct with lumbopelivic fixation and a staged approach in patients with superinfected CSA represents a reasonable option in the surgical treatment of CSA., (This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery. Copyright © 2021 ISASS.)

Vertebral osteomyelitis (VO) is a severe infection of the vertebral body and the adjacent disc space, where Staphylococcus aureus is most commonly isolated. The objective of this retrospective study was to determine risk factors for and compare outcome differences between de novo methicillin-resistant Staphylococcus aureus (MRSA) VO and methicillin-sensitive Staphylococcus aureus (MSSA) VO. A retrospective cohort study was performed by review of the electronic medical records of 4541 consecutive spine surgery patients. Among these 37 underwent surgical treatment of de novo MRSA and MSSA spinal infections. Patient demographics, pre- and postoperative neurological status (ASIA impairment score), surgical treatment, inflammatory laboratory values, nutritional status, comorbidities, antibiotics, hospital stay, ICU stay, reoperation, readmission, and complications were collected. A minimum follow-up (FU) of 12 months was required. Among the 37 patients with de novo VO, 19 were MRSA and 18 were MSSA. Mean age was 52.4 and 52.9 years in the MRSA and MSSA groups, respectively. Neurological deficits were found in 53% of patients with MRSA infection and in 17% of the patients with MSSA infection, which was statistically significant (p < 0.05). Chronic renal insufficiency and malnutrition were found to be significant risk factors for MRSA VO. Preoperative albumin was significantly lower in the MRSA group (p < 0.05). Patients suffering from spinal infection with chronic renal insufficiency and malnutrition should be watched more carefully for MRSA. The MRSA group did not show a significant difference with regard to final clinical outcome despite more severe presentation., (© 2020. Springer-Verlag GmbH Germany, part of Springer Nature.)

Study Design: Retrospective cohort study., Objectives: The study aims to evaluate anterior cervical discectomy and fusion (ACDF) in the treatment of patients with ossification of the anterior longitudinal ligament (OALL)., Methods: We retrospectively reviewed cases performed at our institution between January 2015 and December 2018; adult (age ≥18 years) patients who underwent anterior cervical decompression and fusion in the presence of dysphagia and OALL. Ten patients (9 male, 1 female, mean age 64.4 years) with OALL who underwent ACDF were included. Charts were reviewed for demographics and comorbidities. Primary outcomes assessed were intra- and postoperative complications. Secondary outcomes were fusion rates, instrumentation failure, postsurgical instability/deformity, and readmission rates., Results: The average duration of symptoms prior to surgery was 12.3 months. All patients presented with dysphagia (mean Bazaz score 2.0). The average number of levels with OALL was 4.7 (±1.67). All patients underwent ACDF and 3 patients underwent additional posterior cervical fusion for kyphotic deformity correction or when extensive laminectomy was required. We did not encounter any intraoperative complications. Eight patients (72%) had solid fusion demonstrated on the lateral x-rays and no evidence of progressive kyphotic deformity. We did not encounter any instrumentation failure or loosening. Two patients developed recurrence of dysphagia (Bazaz scores 2 and 3 respectively)., Conclusion: ACDF for OALL with dysphagia and concomitant myelopathy in our small series of 10 patients demonstrate good fusion and clinical outcomes. Larger studies will be necessary to determine the optimal treatment for patients with dysphagia due to OALL.

Sacral fractures are often underdiagnosed but are relatively frequent in the setting of pelvic ring injury. Causes include traumatic insults and osteoporosis. Sacral fractures have become more frequent owing to the growth of the elderly population worldwide as osteoporosis is an age-related disease. Misdiagnosed and neglected sacral fractures can result in chronic back pain, spine deformity, and instability. Unfortunately, the wide range of classification systems hinders adequate communication among clinicians. Therefore, a complete understanding of the pathology, and communication within the interdisciplinary team, are necessary to ensure adequate treatment and satisfactory clinical outcomes. The aim of this manuscript is to present the current knowledge available regarding classification systems, clinical assessment, decision-making factors, and current treatment options., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflict of interest., (Copyright © 2020. Published by Elsevier Ltd.)

Study Design: A retrospective cohort study., Purpose: The aim of this study was to determine any correlations between spinopelvic configuration and progressive collapse following acute osteoporotic compression spine fractures., Overview of Literature: Few studies have investigated the risk factors for progressive osteoporotic compression spine fractures. However, the correlation between the spinopelvic configuration, which is a crucial to optimize the management of lumbar degenerative diseases, and progressive collapse following acute osteoporotic compression spine fractures was not analyzed., Methods: We retrospectively identified all patients treated for thoracolumbar fractures in Assaf Harofe Medical Center between January 2008 and July 2013. Pelvic incidence (PI), sacral slope (SS), and pelvic tilt (PT) were measured for the pelvic parameters. For each patient, we classified the fracture according to the AOSpine Thoracolumbar Spine Injury Classification System. Height loss was measured initially and at a minimum of 3-month follow-up. The difference between initial and final height loss was documented as height loss difference., Results: The study included 124 patients comprised 86 women and 38 men. The mean patient age was 69±9.6 years. The mean length of follow-up was 14±15 months. No significant effect of the PI, PT, and SS angles on the vertebral fracture level (p >0.05) was found. Similarly, no significant relationship between the PI, PT, and SS angle and the fracture type according to the AO classification (p >0.05) was found. There was no correlation between PI, PT, and SS angles and initial height loss, final height loss and height loss difference (p> 0.05)., Conclusions: The spinopelvic configuration represented by the PI, PT, and SS angle does not influence progressive collapse following acute osteoporotic compression spine fractures.

Background: Traumatic spinal injuries can be life-threatening conditions. Despite numerous epidemiological studies, reports on specific spinal regions affected are lacking., Hypothesis: We hypothesized that fractures at specific regions, such as the cervical spine (including the axis segment), have been affected to a greater degree. We also hypothesized that advanced age may be a significant contributing factor., Objective: To longitudinally analyze trend of spine fractures and specific fracture subtypes., Study Design: Longitudinal trend analysis of discharged patient state database., Patient Sample: Discharged patient's data from 15 years (2003-2017) METHODS: We retrieved pertinent ICD-9 and 10 codes depicting fractures involving the entire spine and specific subtypes. To assess possible association with age, we analyzed the trend of the average age in patients discharged with and without spinal fractures as well as in specific fracture subtypes. Similar analysis was performed for other common fragility fractures. FDA device/drug status: The manuscript submitted does not contain information about medical device(s) or drug(s)., Results: We found that within 15 years, the overall proportion of spinal fractures has increased by 64% (from 0.47 to 0.77% of all discharged patients) with the greatest increase noted in fractures of the cervical spine (123%) and specifically of the second cervical vertebra (84%). Age was found to have increased more in patients with spinal fractures than in the general discharged population. Surprisingly, other non-spinal fractures among patients above 60 remained relatively stable, demonstrating a spine-specific effect., Conclusions: Our findings confirm a recent increase in all spinal fractures and in the cervical and sacral regions in particular. Advanced age may be an important underlying factor.

Background: Increasing numbers of unstable pelvic ring fractures, due to the ongoing demographic change and improvements in the rescue of high-energy traumatic events, are challenging trauma and orthopedic surgeons. While initial installation of an external fixation device is often necessary, placement of iliac crest pins can be difficult due to the complex osteology of the ilium., Hypothesis: We aim to analyze (1) the length, localization and angulation of the iliac pillar and (2) to define the dimensions of the surgical corridor for a better understanding of pin entry point and trajectory, thus preventing shortcomings in anterior external fixation of pelvic ring injuries., Methods: Twenty hemipelvises from 10 fresh-frozen cadaveric torsos (3 female, 7 males; mean age 80.2 years) were harvested. The following measurements were taken with digital calipers: Location of the iliac pillar in relation to the anterior superior iliac spine and to the acetabulum roof, mean length and diameter of the iliac pillar, maximum diameter of the iliac pillar. In addition we measured the width of the different bone layers., Results: The mean length of the hourglass shaped iliac pillar was 107.04mm with a mean width of 17.0mm (min. 15.1; max. 19.2). The mean distance to the anterior superior iliac spine was 69.00mm (min. 64.8; max. 73.4). The mean maximum width of the iliac pillar was 12.16mm (min. 9.4; max. 13.8). Caudally the line describing the iliac pillar intercepts the cranial acetabular rim at 12 o'clock. The smallest mean diameter of the cancellous bone was 7.5mm±2.0., Conclusion: The iliac pillar is part of the complex osteology of the human pelvis. A cohesive description of its location and dimensions has been lacking. Successful treatment of pelvic fracture depends on an optimal preoperative planning, accurate overall reduction, and stable fixation. We described the origin and angulation to provide a good bone stock for external fixation pin and the width of the different bone layers. This study therefore contributes by facilitating a thorough understanding of pelvic osteology and describing the location and dimensions of an optimal osseous pathway., Level of Evidence: Anatomical descriptive study., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

In humans, mutations in the PIEZO2 gene, which encodes for a mechanosensitive ion channel, were found to result in skeletal abnormalities including scoliosis and hip dysplasia. Here, we show in mice that loss of Piezo2 expression in the proprioceptive system recapitulates several human skeletal abnormalities. While loss of Piezo2 in chondrogenic or osteogenic lineages does not lead to human-like skeletal abnormalities, its loss in proprioceptive neurons leads to spine malalignment and hip dysplasia. To validate the non-autonomous role of proprioception in hip joint morphogenesis, we studied this process in mice mutant for proprioceptive system regulators Runx3 or Egr3. Loss of Runx3 in the peripheral nervous system, but not in skeletal lineages, leads to similar joint abnormalities, as does Egr3 loss of function. These findings expand the range of known regulatory roles of the proprioception system on the skeleton and provide a central component of the underlying molecular mechanism, namely Piezo2.

Objective: The surgical treatment of osteomyelitis and discitis of the spine often represents a challenging clinical entity for a multitude of reasons, including progression of infection despite debridement, development of spinal deformity and instability, bony destruction, and seeding of hardware. Despite advancement in spinal hardware and implantation techniques, these aforementioned challenges not uncommonly result in treatment failure, especially in instances of heavy disease burden with enough bony endplate destruction as to not allow support of a modern titanium cage implant. While antibiotic-infused polymethylmethacrylate (aPMMA) has been used in orthopedic surgery in joints of the extremities, its use has not been extensively described in the spine literature. Herein, the authors describe for the first time a series of patients treated with a novel surgical technique for the treatment of spinal osteomyelitis and discitis using aPMMA strut grafts with posterior segmental fusion., Methods: Over the course of 3 years, all patients with spinal osteomyelitis and discitis at a single institution were identified and included in the retrospective cohort if they were surgically treated with spinal fusion and implantation of an aPMMA strut graft at the nidus of infection. Basic demographics, surgical techniques, levels treated, complications, and return to the operating room for removal of the aPMMA strut graft and placement of a traditional cage were examined. The surgical technique consisted of performing a discectomy and/or corpectomy at the level of osteomyelitis and discitis followed by placement of aPMMA impregnated with vancomycin and/or tobramycin into the cavity. Depending on the patient's condition during follow-up and other deciding clinical and radiographic factors, the patient may return to the operating room nonurgently for removal of the PMMA spacer and implantation of a permanent cage with allograft to ultimately promote fusion., Results: Fifteen patients were identified who were treated with an aPMMA strut graft for spinal osteomyelitis and discitis. Of these, 9 patients returned to the operating room for aPMMA strut graft removal and insertion of a cage with allograft at an average of 19 weeks following the index procedure. The most common infections were methicillin-sensitive Staphylococcus aureus (n = 6) and methicillin-resistant S. aureus (n = 5). There were 13 lumbosacral infections and 1 each of cervical and thoracic infection. Eleven patients were cured of their infection, while 2 had recurrence of their infection; 2 patients were lost to follow-up. Three patients required unplanned return trips to the operating room, two of which were for wound complications, with the third being for recurrent infection., Conclusions: In cases of severe infection with considerable bony destruction, insertion of an aPMMA strut graft is a novel technique that should be considered in order to provide strong anterior-column support while directly delivering antibiotics to the infection bed. While the active infection is being treated medically, this structural aPMMA support bridges the time it takes for the patient to be converted from a catabolic to an anabolic state, when it is ultimately safe to perform a definitive, curative fusion surgery.

Study Design: . Retrospective study., Objective: . To determine incidence, risk factors, complications, and early postoperative outcome in patients with intraoperative ischemic stroke during elective spine surgery., Summary of Background Data: . Overall, stroke is the fifth leading cause of death in the United States and the second leading cause of death worldwide. It can be a catastrophic event and the main cause of neurological disability in adults., Methods: . A retrospective review of the electronic medical records of patients who underwent elective spine surgery between January 2016 and November 2018 at a larger tertiary referral center was conducted. Patients with infection and neoplastic disease were excluded. Patient demographics, pre- and postoperative neurological status, surgical treatment, surgical time, blood loss, intraoperative abnormalities, risk factors, history of stroke, medical treatment, diagnostics, hospital stay, complications, and mortality were collected., Results: . Out of 5029 surgically treated patients receiving elective spine surgery, a total of seven patients (0.15%) were identified who developed an ischemic stroke during the surgical procedure. Patients were predominantly females (n = 6). Ischemic pontine stroke occurred in two patients. Further distributions of ischemic stroke were: left caudate nucleus, left posterior inferior cerebellar artery, left external capsule, left middle cerebral artery, and acute ischemic supratentorial spots. The main risk factors identified for intraoperative ischemic stroke include hypertension, diabetes, smoking, dyslipidemia, and possibly major intraoperative CSF leak. Three patients (43%) had neurological deficits which did not improve during hospital stay. Two patients recovered fully and two patients died. Therefore, in-hospital mortality rate of this subset of patients was 29%., Conclusion: . With the increase of spinal procedures, it is important to identify patients at risk for having an ischemic stroke and to optimize their comorbidities preoperatively. Patients with intraoperative ischemic stroke carry a higher risk for morbidity and mortality during the index hospitalization., Level of Evidence: 4.

Introduction: The lateral transpsoas approach (LTPA) has gained popularity in thoracolumbar spine surgery procedures; however, there is an insufficient amount of data pertaining to motor and sensory complications that arise when a corpectomy is performed through the LTPA approach., Methods: Patients who underwent a corpectomy through a LTPA at a single institution between 2006 and 2016 were analyzed. Demographics, neurological outcomes, and complications were recorded. The minimum follow-up was 6 months. Univariate analysis was performed to compare demographics, surgical characteristics, complications, and outcome scores. To compare categorical variables, the χ 2 test was used. For continuous outcomes, simple linear regression was used. Statistical significance was set at P < 0.05., Results: A total of 166 patients were included. The patients were divided into 2 groups; LTPA without corpectomy (n = 112) versus LTPA with corpectomy (n = 54). Patients without corpectomy showed a significantly lower rate of postoperative infections compared with patients with corpectomy (3.6% vs. 22.2%; P < 0.000). A higher percentage of postoperative complications was found in patients with corpectomy (31.5% vs. 13.4%; P = 0.006). The rate of neurologic complications at the 6-month follow-up and the reoperation rate (22.7% vs. 32.4%; P = 0.256) were higher in the corpectomy group (8.9% vs. 7.4%; P = 0.741), no significant difference was found between the groups., Conclusion: Patients who underwent an LTPA corpectomy have a higher risk to suffer from postoperative complications. The results at the 6-month follow-up did not significantly differ between the groups., (Published by Elsevier Inc.)

Study Design: Survey analysis among spine surgeons., Objective: To identify current consensus and discrepancies in managing adverse intraoperative events among spine surgeons., Summary of Background Data: Major intraoperative events are not commonly the subject of formal medical training, in part due to the relative paucity of their occurrence and in part due to an insufficient evidence base. Given the clinical impact of appropriate complication management, it is important to identify where surgeons may be able to improve decision making when choosing interventions., Methods: A survey was created including five hypothetical unpredicted scenarios affecting different organ systems to assess the respondents' preferred reactions. The five clinical vignettes that were selected by the researchers involved: 1) loss of spinal signals in neuro-monitoring, 2) prone position cardiac arrest, 3) prone position hypoxia during thoracic corpectomy and instrumentation, 4) supine cervical vertebral artery injury, and 5) sudden onset hypotension in major prone position reconstructive spine surgery. Twenty-eight surveys (Spine Fellows n = 11; Spine surgeon Faculty n = 17) were completed and returned to the investigators. Results were sorted and ranked according to the frequency each action was identified as a top five choice., Results: Following formal statistical evaluation loss of signals in neuro-monitoring had the statistically significantly most uniform response while the scenario involving cardiac compromise had the most heterogeneous. Many "best" responses had near or complete consensus while some "distractor" possibilities that could harm a patient were also selected by the respondents., Conclusion: The heterogeneity of responses in the face of "disaster scenario" intraoperative events shows there is room for more thorough and directed education of spine surgeons during training. As surgical teaching moves toward increased use of patient simulation and situational learning, these vignettes hopefully serve to provide direction for training future spine surgeons on how best to approach difficult situations., Level of Evidence: 4.

Study Design: Epidemiological study., Objective: The aim of this study was to evaluate trends in the incidence of spinal infections (SI) and the possible role of substance use disorder (SUD) as a key associated factor., Summary of Background Data: SI pose major diagnostic and therapeutic challenge in developed countries, resulting in substantial morbidity and mortality. With an estimated incidence of up to 1:20,000, recent clinical experiences suggest that this rate may be rising., Methods: To evaluate a possible change in trend in the proportion of SI, we searched the Washington state Comprehensive Hospital Abstract Reporting System (CHARS) data during a period of 15 years. We retrieved ICD-9 and 10 codes, searching for all conditions that are regarded as SI (discitis, osteomyelitis, and intraspinal abscess), as well as major known SI-related risk factors., Results: We found that the proportion of SI among discharged patients had increased by around 40% during the past 6 years, starting at 2012 and increasing steadily thereafter. Analysis of SI-related risk factors within the group of SI revealed that proportion of SUD and malnutrition had undergone the most substantial change, with the former increasing >3-fold during the same period., Conclusion: Growing rates of drug abuse, drug dependence, and malnutrition throughout the State of Washington may trigger a substantial increase in the incidence of spinal infections in discharged patients. These findings may provide important insights in planning prevention strategies on a broader level., Level of Evidence: 4.

Study Design: Systematic review., Introduction: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease, ultimately resulting in paralysis and death. The condition is considered to be caused by a complex interaction between environmental and genetic factors. Although vast genetic research has deciphered many of the molecular factors in ALS pathogenesis, the environmental factors have remained largely unknown. Recent evidence suggests that participation in certain types of sporting activities are associated with increased risk for ALS., Objective: To test the hypothesis that competitive sports at the highest level that involve repetitive concussive head and cervical spinal trauma result in an increased risk of ALS compared with the general population or nonsport controls., Methods: Electronic databases from inception to November 22, 2017 and reference lists of key articles were searched to identify studies meeting inclusion criteria., Results: Sixteen studies met the inclusion criteria. Sports assessed (professional or nonprofessional) included soccer (n = 5), American football (n = 2), basketball (n = 1), cycling (n = 1), marathon or triathlon (n = 1), skating (n = 1), and general sports not specified (n = 11). Soccer and American football were considered sports involving repetitive concussive head and cervical spinal trauma. Professional sports prone to repetitive concussive head and cervical spinal trauma were associated with substantially greater effects (pooled rate ratio [RR] 8.52, 95% CI 5.18-14.0) compared with ( a ) nonprofessional sports prone to repetitive concussive head and cervical spinal trauma (pooled RR 0.60, 95% CI 0.12-3.06); ( b ) professional sports not prone to repetitive head and neck trauma (pooled RR 1.35, 95% CI 0.67-2.71); or ( c ) nonprofessional sports not prone to repetitive concussive head and cervical spinal trauma (pooled RR 1.17, 95% CI 0.79-1.71)., Conclusions: Our review suggests that increased susceptibility to ALS is significantly and independently associated with 2 factors: professional sports and sports prone to repetitive concussive head and cervical spinal trauma. Their combination resulted in an additive effect, further increasing this association to ALS., Competing Interests: Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Meticulous attention to wound closure in posterior lumbar spine surgery is an important principle in reducing surgical site infections. We detail standardized wound closure used for posterior lumbar spine surgery at a tertiary care referral center and illustrate this as a step-by-step cadaveric dissection. The lumbar spine of a cadaveric specimen (male, 73 years at death) was used for dissection. Standardizing wound closure in posterior lumbar spine surgery may help limit wound complications and infection. Some key points of our technique, as demonstrated on a cadaveric specimen, include separating fascial compartments, avoiding suture abscesses, and creating a tension-free wound., Competing Interests: The authors have declared that no competing interests exist.

Muscle spindles and Golgi tendon organs (GTOs) are two types of sensory receptors that respond to changes in length or tension of skeletal muscles. These mechanosensors have long been known to participate in both proprioception and stretch reflex. Here, we present recent findings implicating these organs in maintenance of spine alignment as well as in realignment of fractured bones. These discoveries have been made in several mouse lines lacking functional mechanosensors in part or completely. In both studies, the absence of functional spindles and GTOs produced a more severe phenotype than that of spindles alone. Interestingly, the spinal curve phenotype, which appeared during peripubertal development, bears resemblance to the human condition adolescent idiopathic scoliosis. This similarity may contribute to the study of the disease by offering both an animal model and a clue as to its aetiology. Moreover, it raises the possibility that impaired proprioceptive signalling may be involved in the aetiology of other conditions. Overall, these new findings expand considerably the scope of involvement of proprioception in musculoskeletal development and function.This article is part of the Theo Murphy meeting issue 'Mechanics of development'., (© 2018 The Author(s).)

Study Design: Systematic review., Objectives: In patients undergoing posterior spinal fusion: (1) What are the types and risks of wound complications in major (≥3 levels) surgery, and does the risk vary by number of levels fused? (2) What types of fascial closure result in the fewest wound complications? (3) What subcutaneous closure technique is more effective in preventing wound complications for obese patients (body mass index >30 kg/m 2 )? (4) What type of skin closure results in the fewest wound complications? (5) What type of dressing results in the fewest wound complications?, Methods: Electronic databases and reference lists of key articles were searched from January 1, 2000 to December 4, 2017 to identify studies meeting inclusion criteria., Results: Six lower quality retrospective studies (evidence level III) met the inclusion criteria. The risk of wound complications in patients with ≥3 level posterior spine fusion ranges from 1.5% to 3.7% depending on the definition of wound complications. Skin closure with sutures resulted in fewer wound infections compared with staples (0.0% vs 8.0%, P = .023). We were unable to demonstrate an association between the number of levels fused and infection risk. Wound infections, primarily superficial, occurred less frequently with Silverlon dressing versus routine dressing., Conclusions: We were unable to determine if infection risk changed with increasing number of levels fused. There is a lack of evidence for optimal wound closure technique in posterior spine surgery. Several questions still remain unanswered, such as the optimal fascial closure technique or the optimal subcutaneous closure technique in obese patients., Competing Interests: Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

The authors describe a 67-year-old man with a prior history of alcohol abuse who presented with a complaint of worsening low back pain. Four months prior to his presentation, the patient had undergone extreme lateral interbody fusion (XLIF) of his lumbar 3-4 segment for the treatment of his chronic low back and legs pain. Imaging revealed a loosening of his interbody fusion implant on top of his prior lumbar spine instrumentation. In surgery, the removal of his loose implant was followed by decompression, the stabilization of the collapsed segment, and the implant of antibiotic-impregnated polymethyl-methacrylate (PMMA) spacer and beads. At a later stage, the patient underwent an interbody fusion of the affected segment as well as a segmental fusion from T10 to his pelvis. Whereas all aerobes and anaerobes stains were negative for organisms, multiple fungal smears from the failed segment were positive for yeast, and the patient was placed on oral fluconazole. Infections complicating the surgical site of interbody fusions performed by minimally invasive techniques are rare. To the best of our knowledge and after reviewing the literature, this is the first report of an extreme lateral interbody fusion implant complicated by fungal osteomyelitis., Competing Interests: The authors have declared that no competing interests exist.

Background: The S2 alar-iliac (S2AI) screw is a modification of the iliac fixation technique using the space between the neuroforamina of S1 and S2 as an insertion point to fix the sacrum to the ilium. To our knowledge, an anatomic review of the S2AI technique has not been described and the insertion point is vague and angles differ in reports from the literature. The purpose of the current anatomic illustration is to provide step-by-step techniques with fluoroscopic imaging to help confirm the safe placement of S2AI screws., Methods: The procedure was performed on the left and rights sides of a fresh, frozen, and thawed predissected male cadaver in a surgical training facility through a standard posterior midline exposure for placement of the S2AI screws. All screws were placed by a fellowship-trained spine surgeon and an attending spine surgeon., Results: The specimen was placed prone, and a midline incision begun at the L4 or L5 spinous process. Using the anteroposterior and inlet views, the S1 dorsal sacral foramen, the S1 endplate, and the sacroiliac joint can be identified. The insertion point is 10 mm laterally between the S1 and S2 foramina and near to the sacroiliac joint. Aim toward the anterior inferior iliac spine is ensured by using a 30°-40° lateral angulation in the transverse plane and 20°-30° caudal angulation in the sagittal plane depending on the sacral angulation. Using lateral fluoroscopy, the acetabulum and greater sciatic notch can be identified and screw misplacement can be avoided. The screw length is measured and is usually between 60 and 90 mm (8- to 9-mm diameter). An elevator is used to identify the outer sacral cortex. Anteroposterior, obturator-outlet, and teardrop views are used to ensure correct screw insertion., Conclusions: Fluoroscopic guidance is crucial for optimal S2AI screw placement. Using the described technique allows a safe and correct insertion of the S2AI screw., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Introduction
 The extreme lateral interbody fusion technique (XLIF) is a modification of the retroperitoneal approach to the lumbar spine. This is a minimally invasive technique allowing direct access to the disc space without peritoneal or posterior paraspinal musculature damage. Nevertheless, the retroperitoneal part of the colon can be injured in this operative technique. To our knowledge, a study analyzing the anatomical considerations of the extreme lateral interbody fusion technique with regards to potential colon injuries has not been previously performed. Therefore, the aim of this study was to evaluate the potential risk of colon injuries during the extreme lateral approach to the lumbar spine. Materials and Methods
 The extreme lateral approach to the lumbar spine was performed on four fresh-frozen cadaveric sides. K-wires were placed into the intervertebral discs and positioned at L1/L2, L2/L3, L3/L4, and L4/L5 levels. Next, the distances from the wires to the most posterior aspect of the adjacent ascending or descending colon were measured.
 Results
 The mean distance from the intervertebral disc space to the ascending or descending colon was 23.2 mm at the L2/L3 level, 29.5 mm at the L3/L4 level, and 40.3 mm at the L4/L5 level. The L1/L2 level was above the colon on both sides.
 Conclusion
 Our study quantified the relationship of the retroperitoneal colon during an extreme lateral interbody fusion approach. Our results, as well as previously described cases of bowel perforations, suggest a greater risk for colon injuries at the L2/3 and L3/4 levels.​​​​​​​., Competing Interests: The authors have declared that no competing interests exist.

Microglia are embryonically seeded macrophages that contribute to brain development, homeostasis, and pathologies. It is thus essential to decipher how microglial properties are temporally regulated by intrinsic and extrinsic factors, such as sexual identity and the microbiome. Here, we found that microglia undergo differentiation phases, discernable by transcriptomic signatures and chromatin accessibility landscapes, which can diverge in adult males and females. Remarkably, the absence of microbiome in germ-free mice had a time and sexually dimorphic impact both prenatally and postnatally: microglia were more profoundly perturbed in male embryos and female adults. Antibiotic treatment of adult mice triggered sexually biased microglial responses revealing both acute and long-term effects of microbiota depletion. Finally, human fetal microglia exhibited significant overlap with the murine transcriptomic signature. Our study shows that microglia respond to environmental challenges in a sex- and time-dependent manner from prenatal stages, with major implications for our understanding of microglial contributions to health and disease., (Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.)

The authors describe a 48-year-old woman suffering from bilateral upper-extremity numbness and axial radiating pain. Magnetic resonance imaging revealed soft-tissue edema and enhancement surrounding the dorsal tip of the C7 spinous process. Excisional biopsy of the lesion revealed a mildly inflamed bursa, with no evidence of an active infection. Removal of the inflamed bursa resulted in complete resolution of the upper-extremity numbness and improvement in her neck pain. Although similar cases have been reported to be associated with rheumatologic conditions, most notably polymyalgia rheumatica (PMR), the current report underlines the presentation of radicular-like complaints associated with interspinous bursitis in the absence of other conditions affecting the musculoskeleton., Competing Interests: The authors have declared that no competing interests exist.

Successful fracture repair requires restoration of bone morphology and mechanical integrity. Recent evidence shows that fractured bones of neonatal mice undergo spontaneous realignment, dubbed "natural reduction." Here, we show that natural reduction is regulated by the proprioceptive system and improves with age. Comparison among mice of different ages revealed, surprisingly, that 3-month-old mice exhibited more rapid and effective natural reduction than newborns. Fractured bones of null mutants for transcription factor Runx3, lacking functional proprioceptors, failed to realign properly. Blocking Runx3 expression in the peripheral nervous system, but not in limb mesenchyme, recapitulated the null phenotype, as did inactivation of muscles flanking the fracture site. Egr3 knockout mice, which lack muscle spindles but not Golgi tendon organs, displayed a less severe phenotype, suggesting that both receptor types, as well as muscle contraction, are required for this regulatory mechanism. These findings uncover a physiological role for proprioception in non-autonomous regulation of skeletal integrity., (Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.)

Maintaining posture requires tight regulation of the position and orientation of numerous spinal components. Yet, surprisingly little is known about this regulatory mechanism, whose failure may result in spinal deformity as in adolescent idiopathic scoliosis. Here, we use genetic mouse models to demonstrate the involvement of proprioception in regulating spine alignment. Null mutants for Runx3 transcription factor, which lack TrkC neurons connecting between proprioceptive mechanoreceptors and spinal cord, developed peripubertal scoliosis not preceded by vertebral dysplasia or muscle asymmetry. Deletion of Runx3 in the peripheral nervous system or specifically in peripheral sensory neurons, or of enhancer elements driving Runx3 expression in proprioceptive neurons, induced a similar phenotype. Egr3 knockout mice, lacking muscle spindles, but not Golgi tendon organs, displayed a less severe phenotype, suggesting that both receptor types may be required for this regulatory mechanism. These findings uncover a central role for the proprioceptive system in maintaining spinal alignment., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Osteoporotic compression spine fractures have a different clinical course and outcomes when compared to spinal fractures occurring in the younger population. Only a few studies have investigated the risk factors for progressive osteoporotic compression spine fractures. The purpose of this study was to investigate clinical and radiological factors related to progressive collapse following acute osteoporotic compression spine fractures. We retrospectively identified all patients treated for thoracolumbar fractures in our institution between January 2008 and July 2013. Included cases were examined by plain radiographs and CT scans. For each patient we classified the fracture according to the AOSpine Thoracolumbar Spine Injury Classification System. The difference between initial and final height loss and initial and final local kyphosis was documented as height loss difference and kyphotic angle difference. The presence of old fractures and intravertebral cleft were also documented. The study included 153 patients, comprising 102 women and 51 men. The mean patient age was 68.9years. The mean length of follow up was 15months. A statistically significant correlation was found between patient age, final height loss, height loss difference and kyphotic angle difference. Height loss difference and kyphotic angle difference were significantly correlated to type of fracture according to the AO classification system. The height loss difference was 18.1% in A1 type fractures, 27.1% in A2 type fractures, 24.2% in A3 type fractures and 25.7% in A4 type fractures. During a minimum 3-month follow up of conservative treatment for acute osteoporotic vertebral compression fractures, age and the AOSpine Thoracolumbar Spine Injury Classification System were predictive factors for progressive collapse., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Treatment of fractured bones involves correction of displacement or angulation, known as reduction. However, angulated long-bone fractures in infants often heal and regain proper morphology spontaneously, without reduction. To study the mechanism underlying spontaneous regeneration of fractured bones, we left humeral fractures induced in newborn mice unstabilized, and rapid realignment of initially angulated bones was seen. This realignment was surprisingly not mediated by bone remodeling, but instead involved substantial movement of the two fragments prior to callus ossification. Analysis of gene expression profiles, cell proliferation, and bone growth revealed the formation of a functional, bidirectional growth plate at the concave side of the fracture. This growth plate acts like a mechanical jack, generating opposing forces that straighten the two fragments. Finally, we show that muscle force is important in this process, as blocking muscle contraction disrupts growth plate formation, leading to premature callus ossification and failed reduction.

Study Design: A retrospective case study., Purpose: To retrospectively review all incidental dural tears (DTs) that occurred at a single institution, classify them anatomically and evaluate the clinical significance of each subgroup., Overview of Literature: Dural tears are considered the most commonly encountered complication during lumbar spine surgery. In contrast to the high frequency of DTs, reports on the characteristic location and mechanism are sparse., Methods: We retrospectively retrieved all cases of degenerative lumbar spine surgery performed over a 9-year period and classified all identified DTs according to two independent planes. The coronal plane was divided into lower, middle and upper surgical fields, and the sagittal plane into posterior, lateral and ventral occurring tears. Demographic and clinical variables were retrieved and analyzed to search for significant associations., Results: From 2003 to 2011, 1,235 cases of degenerative lumbar spine conditions were treated surgically at our institution. In 84 operations (6.8%), an incidental DT was either identified intraoperatively or suspected retrospectively. The most commonly involved location was the lower surgical field (n=39, 46.4%; p=0.002), followed equally by the middle and upper fields (n=16, 19%). In the sagittal plane, the most commonly involved locations were those in close proximity to the nerve root (n=35, 41.6%), followed by the dorsal aspect of the dural sac (n=24, 28.6%). None of the variables recorded was found to be associated with a particular location., Conclusions: In our series, incidental DTs were found to occur most commonly in the lower surgical field. We hypothesize that local anatomic feature, such as the lordotic and broadening lumbar dura, may play a role in the observed DT tendency to occur in the lower surgical field. In light of the high frequency and potentially substantial resulting morbidity of incidental DTs, a better characterization of its location and mechanism may optimize both prevention and management.

Background: Osteoporosis is considered the most common bone disease in humans and the most common cause of fractures., Objectives: To identify possible risk factors associated with a low level of care for osteoporosis in patients presenting acutely with the major types of fragility fractures, as well as in patients who remain undertreated following their discharge., Methods: We conducted a retrospective questionnaire-based cohort study. We searched our databases for patients admitted acutely with proximal humerus, distal forearm, thoraco-lumbar spine, and proximal femur fractures. A questionnaire was used to evaluate osteoporotic care including a referral to DEXA and any associated prescribed medication., Results: The study group included 114 patients or their caregivers. The osteoporosis care rate rose from 56.1% (n = 64) before admission to 71% (n = 81) at follow-up. Significant risk factors associated with a decreased care rate prior to admission were the presence of fewer than three comorbidities and a combination of male gender and young age. Continued neglect at follow-up was associated with the opposite risk factors, such as older age, multiple comorbidities, and polypharmacy. An additional finding was that treated patients had a significantly increased likelihood of presenting with vertebral fractures., Conclusions: While the association of osteoporosis with the elderly may decrease screening rates among younger and healthier patients, fragility fractures may be viewed as "endstage" bone disease, rendering osteoporotic care inefficient.

Background: A diagnosis of cervical radiculopathy is based largely on clinical examination, including provocative testing. The most common maneuver was described in 1944 by Spurling and Scoville. Since then, several modifications of the original maneuver have been proposed to improve its value in the diagnosis of cervical radiculopathy., Questions/purposes: We assessed the ability of six known variations of the Spurling test to reproduce the complaints of patients diagnosed with cervical radiculopathy., Methods: We prospectively enrolled 67 patients presenting with cervical radicular-like symptoms and concordant radiographic findings. Each patient underwent six distinct provocative cervical spine maneuvers by two examiners, during which three parameters were recorded: (1) pain intensity (VAS score), (2) paresthesia intensity (0 - no paresthesia, 1 - mild to moderate, and 2 - severe), and (3) characteristic pain distribution (0 - no pain, 1 - neck pain only, 2 - arm pain only, 3 - pain elicited distal to the elbow). The interobserver reliability of the reported VAS score (measured by the intraclass coefficient correlation) ranged from 0.78 to 0.96 and the calculated kappa values of the categorical parameters ranged from 0.58 to 1.0 for paresthesia intensity and from 0.63 to 1.0 for pain distribution. Differences in scores elicited between the two examiners for the 67 patients were resolved by consensus., Results: A maneuver consisting of extension, lateral bending, and axial compression resulted in the highest VAS score (mean, 7) and was associated with the most distally elicited pain on average (mean, 2.5). The highest paresthesia levels were reported after applying extension, rotation, and axial compression (mean, 1). These maneuvers, however, were the least tolerable, causing discontinuation of the examination on three occasions., Conclusions: Whenever cervical radiculopathy is suspected our observations suggest the staged provocative maneuvers that should be included in the physical evaluation are extension and lateral bending first, followed by the addition of axial compression in cases with an inconclusive effect.

Study Design: Retrospective study., Objective: To analyze our experience in the treatment of symptomatic vertebral hemangioma, review the relevant literature, and propose a management algorithm., Summary of Background Data: Hemangioma is one of the commonest benign neoplasms affecting the vertebral column. These usually dormant lesions may become symptomatic by causing pain, neurologic deficit, or both. Several treatment modalities are available in the management of such symptomatic conversion., Methods: The clinical and radiographic data of 6 patients diagnosed with symptomatic vertebral hemangioma and treated at our medical center over a period of 10 years were reviewed and analyzed retrospectively., Results: Six patients were diagnosed with symptomatic vertebral hemangioma between 1998 and 2008. The lesions occupied the thoracic, lumbar, or multiple segments. Our patients presented with either simple or radicular back pain. One patient had muscle weakness, 3 revealed sensory impairment, and the remaining 2 were neurologically intact. Four patients underwent preoperative transarterial embolization followed by laminectomy and vertebroplasty of the affected level and 2 patients were treated with vertebroplasty alone. A 35-year-old woman presented during pregnancy. Her clinical course during evaluation was complicated by an acute pulmonary embolic event that necessitated installation of an inferior vena cava filter. All patients had an overall uneventful postoperative course and reported symptomatic relief to varying degrees, at an average follow-up period of 35 months., Conclusions: Symptomatic hemangioma involving the vertebral column may pose a therapeutic challenge, often requiring the active involvement of several disciplines. A review of the relevant literature, however, discloses only few management algorithms for such lesions. The coupling of preoperative transarterial embolization followed by vertebroplasty, with or without surgical decompression depending on the patients' presenting symptoms, is a relatively safe treatment and may offer long-term symptomatic relief in these patients. Other aspects of treatment are further discussed.

Ulnar nerve entrapment is one of the most common entrapment neuropathies in the upper limb. The most frequent location of this syndrome is behind the elbow. The clinical picture is associated with the localization of the entrapment but usually consists of an altered sensation at the fourth and fifth digits and a weakness of the intrinsic muscles of the palm. The most constructive tool in making the diagnosis and in assessing the treatment's efficacy is the physical examination. Treatment alternatives depend on entrapment location. Conservative treatment options such as rest, a change in the work environment and patterns as well as splints are all accepted modalities. A lack of improvement following conservative treatment or a deteriorating nerve function is an indication for surgical intervention. This includes procedures comprised of decompression of the ulnar nerve alone or those which combine its transposition.