A Current Update on Pelvifemoral Conditions That Should be in the Differential Diagnosis for Patients With Lower Extremity Radiculopathy.

Patients presenting to an outpatient spine clinic frequently report symptoms of low back pain with associated buttock, groin, and lower extremity pain. While many of these individuals suffer from lumbar spine radiculopathy, a number of different orthopedic pathologies can mimic these symptoms. Management depends substantially on a detailed history and physical examination, in addition to working from a broad list of differential diagnoses when evaluating these patients. It is imperative that spine practitioners have a comprehensive understanding of the differential diagnoses that may mimic those originating from the lumbar spine, especially when a patient's symptoms are atypical from classic radicular pain. Misdiagnosis can lead to unnecessary testing and treatment, while delaying an accurate clinical assessment and treatment plan. This review highlights common orthopedic diagnoses that may present similar to lumbar spine pathologies and the evidence-based evaluation of these conditions.

Activity of immunoproteasome inhibitor ONX-0914 in acute lymphoblastic leukemia expressing MLL-AF4 fusion protein.

Proteasome inhibitors bortezomib and carfilzomib are approved for the treatment of multiple myeloma and mantle cell lymphoma and have demonstrated clinical efficacy for the treatment of acute lymphoblastic leukemia (ALL). The t(4;11)(q21;q23) chromosomal translocation that leads to the expression of MLL-AF4 fusion protein and confers a poor prognosis, is the major cause of infant ALL. This translocation sensitizes tumor cells to proteasome inhibitors, but toxicities of bortezomib and carfilzomib may limit their use in pediatric patients. Many of these toxicities are caused by on-target inhibition of proteasomes in non-lymphoid tissues (e.g., heart muscle, gut, testicles). We found that MLL-AF4 cells express high levels of lymphoid tissue-specific immunoproteasomes and are sensitive to pharmacologically relevant concentrations of specific immunoproteasome inhibitor ONX-0914, even in the presence of stromal cells. Inhibition of multiple active sites of the immunoproteasomes was required to achieve cytotoxicity against ALL. ONX-0914, an inhibitor of LMP7 (ß5i) and LMP2 (ß1i) sites of the immunoproteasome, and LU-102, inhibitor of proteasome ß2 sites, exhibited synergistic cytotoxicity. Treatment with ONX-0914 significantly delayed the growth of orthotopic ALL xenograft tumors in mice. T-cell ALL lines were also sensitive to pharmacologically relevant concentrations of ONX-0914. This study provides a strong rationale for testing clinical stage immunoproteasome inhibitors KZ-616 and M3258 in ALL.

Evidence-Based Management of Spinal Conditions in the Elite Athlete.

Spinal injuries are common and are a significant burden in the professional athlete population. From single-level disk herniation to career-ending fractures, the consequences of these conditions vary widely. Both contact and noncontact injuries can substantially affect the health and performance of elite athletes competing in a variety of sports. The nature and severity of these injuries have great influence on the prospects for full recovery and successful return to play. Common spinal injuries, management decisions, and return to play prospects are important considerations in the professional athlete population.

Pelvic incidence in a femoroacetabular impingement population.

OBJECTIVE: We aim to determine if pelvic incidence (PI) differed between a symptomatic femoroacetabular impingement (FAI) population and a control. METHODS: We retrospectively identified a cohort of symptomatic FAI patients and compared measured PI to a control group. RESULTS: The PI was significantly lower in the FAI group compared to the control (51.32±1.07 vs. 55.63±1.04; P < 0.01). CONCLUSION: The mean PI was significantly decreased in the FAI population compared to a control.

Pennate actuators: force, contraction and stiffness.

Hierarchical actuators are comprised of multiple individual actuator elements arranged into a system, resulting in improved and expanded performance. Natural muscle tissue is a complex and multi-level example of hierarchical actuation, with its hierarchy spanning from the micrometer to the centimeter scale. In addition to a hierarchical configuration, muscle tissue exists in varying geometric arrangements. Pennate muscle tissue, denoted by its characteristic fibers extending obliquely away from the muscle tissue line of action, leverages geometric complexity to transform the relationship between fiber inputs and muscle tissue outputs. In this paper, a bioinspired hierarchical pennate actuator is detailed. This work expands on previous pennate actuator studies by deriving constitutive force, contraction, and stiffness models for a general pennate actuator, where the constituent fibers can be constructed from any linear actuator. These models are experimentally validated by studying a pennate actuator with McKibben artificial muscles constituting the actuator fibers. McKibben artificial muscles are used because they have a high force-to-weight ratio and are inexpensive to construct, making them an attractive candidate for hierarchical actuators and mobile robotics. Using the derived constitutive models, general pennate actuator performance is better understood by analyzing the transmission ratio, blocked force, and free contraction. Loaded contractions and stiffness during isotonic and isobaric contractions are also explored. The results allow for informed design decisions and an understanding of the associated tradeoffs when recreating the remarkable properties of pennate musculature. Future work will leverage the results of this paper to create an adaptive pennate actuator that is capable of changing configuration in response to force, contraction and stiffness demands.

No S.C.A.R.E. Protocol: A Streamlined Safety Protocol.

INTRODUCTION: Despite the proven success of anterior cervical surgery (ACS) postoperative issues can arise, with retropharyngeal hematoma (RH) being one of the most feared. A recent USA Today article highlighted the failed management and subsequent death of patients developing RH after ACS. The article calls into question the safety of performing ACS in an outpatient setting. METHODS: We tested the knowledge of 20 healthcare professionals (4 surgeons, 16 ancillary providers) regarding ways to minimize the post-ACS complications. We used a multiple-choice and fill-in-the-blank test. We then developed a No S.C.A.R.E. safety protocol and after teaching the same professionals, re-administered the examination to assess improvement. RESULTS: We identified large gaps in knowledge between spine surgeons and other providers (92.3% versus 31.2%) on preintervention testing. Postintervention testing showed significant improvement in nonsurgeon scores (31.2% to 86.1%, P < 0.01). Improvement was also seen in provider confidence after completion of the education module. CONCLUSION: Previous studies demonstrate that the incidence of RH necessitating evacuation after ACS is extremely small (<1%). For rare complications, healthcare teams may benefit from educational modules and standardized protocols. After implementation of our No S.C.A.R.E. protocol, provider knowledge and confidence markedly improved. We recommend similar education modules and protocols be used at other institutions performing ACS.

Burden of Sciatica on US Medicare Recipients.

OBJECTIVE: This study evaluates the disease burden of sciatica on the US Medicare cohort. BACKGROUND DATA: Sciatica is a common disability that has important physical, mental, and economic effects. The Medicare Health Outcomes Survey (HOS) is a demographic and outcomes survey used to monitor the performance of Medicare Advantage health plans in the United States. The HOS includes data on demographics, chronic medical conditions, and patient-reported outcomes. METHODS: Medicare HOS data for cohorts from 2007 to 2013 were obtained. Patients were placed into two categories based on the survey results: with or without a history of sciatica. Baseline demographics, chronic medical conditions, and physical health symptoms were aggregated. In addition, average VR-12 physical component summary and mental component summary scores were calculated for each group at baseline and at 2-year follow-up. A Fisher exact test was used to assess significance for categorical variables, and a t-test was used for continuous variables. VR-12 changes as small as 1 to 2 units have been found to be clinically and socially relevant. RESULTS: The baseline cohort data of 1,000,952 patients yielded 250,869 patients (25%) who reported the diagnosis of sciatica, compared with 750,083 patients (75%) without sciatica. Patients with a history of sciatica tended to be younger, less educated, and notably with more medical comorbidities. Physical component summary outcomes were approximately 8 units lower in the sciatica group at baseline and 7 units lower at 2-year follow-up. Mental component summary outcomes were 6 units lower in the sciatica group at baseline and 5 units lower at 2-year follow-up. CONCLUSION: A large percentage of the US Medicare cohort suffers from symptomatic sciatica. Our study identified a 25% prevalence in the Medicare cohort. In addition, sciatica is associated with an increased incidence of comorbid medical conditions and poor health-related quality of life. LEVEL OF EVIDENCE: Level III STUDY DESIGN:: Observational-Cohort Study.

Can the American College of Surgeons Risk Calculator Predict 30-day Complications After Spine Surgery?

MINI: It is unclear whether the ACS NSQIP Surgical Risk Calculator can predict 30-day complications after lumbar and cervical spinal fusions. This study shows that the Risk Calculator is only of marginal benefit in predicting outcomes in cervical fusion and unlikely to be of benefit in lumbar fusions. STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The aim of this study was to assess the American College of Surgeons National Surgery Quality Improvement Program (ACS NSQIP) Risk Calculator's ability to predict 30-day complications after spine surgery. SUMMARY OF BACKGROUND DATA: Surgical risk calculators may identify patients at increased risk for complications, improve outcomes, enhance the informed consent process, and help modify risk factors. The ACS NSQIP Risk Calculator was developed from a cohort of >1.4 million patients, using 2805 unique CPT codes. It uses 21 patient predictors and the planned procedure to predict the risk of 12 different outcomes within 30 days following surgery. METHODS: A retrospective chart review was performed on patients who underwent primary lumbar and cervical fusions with at least 30-day postoperative follow-up between 2009 and 2015 at a single-institution. Descriptive statistics were calculated for the overall sample, anterior versus posterior fusion (cervical only), and single versus multilevel fusion. Logistic regression models were fit with actual complication occurrence as the dependent variable in each model and ACS estimated risk as the independent variable. The c-statistic was used as the measure of concordance for each model. Receiver-operating charateristic curves depicted the predictive ability of the estimated risks. Acceptable concordance was set at c >0.80. RESULTS: A total of 237 lumbar and 404 cervical patients were included in the study. The Risk Calculator risk estimates significantly predicted (P < 0.001) "any complication" and "discharge to skilled nursing facility" among the cervical cohort and demonstrated no significant outcome prediction the lumbar cohort. CONCLUSION: The ACS Risk-Calculator accurately predicted complications in the categories of "any complication" and "discharge to skilled nursing facility" for our cervical cohort and failed to demonstrate benefit for our lumbar cohort. Although the ACS Risk-Calculator may be useful in general surgery, our findings demonstrate that it does not necessarily provide accurate information for patients undergoing spinal surgery. LEVEL OF EVIDENCE: 3.

Retrospective cohort study. The aim of this study was to assess the American College of Surgeons National Surgery Quality Improvement Program (ACS NSQIP) Risk Calculator's ability to predict 30-day complications after spine surgery. Surgical risk calculators may identify patients at increased risk for complications, improve outcomes, enhance the informed consent process, and help modify risk factors. The ACS NSQIP Risk Calculator was developed from a cohort of >1.4 million patients, using 2805 unique CPT codes. It uses 21 patient predictors and the planned procedure to predict the risk of 12 different outcomes within 30 days following surgery. A retrospective chart review was performed on patients who underwent primary lumbar and cervical fusions with at least 30-day postoperative follow-up between 2009 and 2015 at a single-institution. Descriptive statistics were calculated for the overall sample, anterior versus posterior fusion (cervical only), and single versus multilevel fusion. Logistic regression models were fit with actual complication occurrence as the dependent variable in each model and ACS estimated risk as the independent variable. The c-statistic was used as the measure of concordance for each model. Receiver-operating charateristic curves depicted the predictive ability of the estimated risks. Acceptable concordance was set at c >0.80. A total of 237 lumbar and 404 cervical patients were included in the study. The Risk Calculator risk estimates significantly predicted (P < 0.001) "any complication" and "discharge to skilled nursing facility" among the cervical cohort and demonstrated no significant outcome prediction the lumbar cohort. The ACS Risk-Calculator accurately predicted complications in the categories of "any complication" and "discharge to skilled nursing facility" for our cervical cohort and failed to demonstrate benefit for our lumbar cohort. Although the ACS Risk-Calculator may be useful in general surgery, our findings demonstrate that it does not necessarily provide accurate information for patients undergoing spinal surgery. Level of Evidence: 3.

Can the American College of Surgeons Risk Calculator Predict 30-Day Complications After Cervical Spine Surgery?

STUDY DESIGN: This was a retrospective cohort study. OBJECTIVE: The objective of this study was to assess the American College of Surgeons (ACS) Risk Calculator's ability to accurately predict complications after cervical spine surgery. SUMMARY OF BACKGROUND DATA: Surgical risk calculators exist in many fields and may assist in the identification of patients at increased risk for complications and readmissions. Risk calculators may allow for improved outcomes, an enhanced informed consent process, and management of modifiable risk factors. The American College of Surgeons National Surgery Quality Improvement Program (ACS NSQIP) Risk Calculator was developed from a cohort of over 1.4 million patients, using 2805 unique Current Procedural Terminology (CPT) codes. The risk calculator uses 21 patient predictors (eg, age, American Society of Anesthesiologists class, body mass index, hypertension) and the planned procedure (CPT code) to predict the chance that patients will have any of 12 different outcomes (eg, death, any complication, serious complication, reoperation) within 30 days following surgery. The purpose of this study is to determine if the ACS NISQIP risk calculator can predict 30-day complications after cervical fusion. METHODS: A retrospective chart review was performed on patients that underwent primary cervical fusions between January 2009 and 2015 at a single institution, utilizing cervical fusion CPT codes. Patients without 30 days of postoperative follow-up were excluded. Descriptive statistics were calculated for the overall sample, anterior versus posterior fusion, and single versus multilevel fusion. Logistic regression models were fit with actual complication occurrence as the dependent variable in each model and ACS estimated risk as the independent variable. The c-statistic was used as the measure of concordance for each model. Receiver operating characteristic curves were plotted to visually depict the predictive ability of the estimated risks. Acceptable concordance was set at c>0.80. All analyses were conducted using SAS, v9.4. RESULTS: A total of 404 patients met the inclusion criteria for this study. Age, body mass index, sex, and a number of levels of fusion were gathered as input data the ACS NSQIP Risk Calculator. Results of Risk Calculator were compared with observed complication rates. Descriptive statistics of the Risk Calculator risk estimates showed a significant prediction of "any complication" and "discharge to skilled nursing facility" among the cohort. Because there were no deaths or urinary tract infections, no models were fit for these outcomes. CONCLUSIONS: The ACS Risk Calculator accurately predicted complications in the categories of "any complication" (P<0.0001) and "discharge to the skilled nursing facility" (P<0.001) for our cohort. We conclude that the ACS Risk Calculator was unable to accurately predict specific complications on a more granular basis for the patients of this study. Although the ACS risk calculator may be useful in the field of general surgery and in the development of new institutional strategies for risk mitigation, our findings demonstrate that it does not necessarily provide accurate information for patients undergoing cervical spinal surgery.

The use of a novel tablet application to quantify dysfunction in cervical spondylotic myelopathy patients.

BACKGROUND CONTEXT: Despite the prevalence and importance of myelopathy, there is a paucity of objective and quantitative clinical measures. The most commonly used diagnostic tools available are nonquantitative physical exam findings (eg, pathologic reflexes, and gait disturbance) and subjective scoring systems (eg, modified Japanese Orthopaedic Association [mJOA]). A decline in fine motor coordination is a hallmark of early myelopathy, which may be useful for quantitative testing. PURPOSE: To identify if a novel tablet application could provide a quantitative measure of upper extremity dysfunction in cervical spondylotic myelopathy. STUDY DESIGN/SETTING: Prospective cohort study Patient Sample: Adult patients with a diagnosis of cervical spondylotic myelopathy from a board-certified, spine surgeon were compared with age-matched, healthy, and adult control patients. OUTCOME MEASURES: Self-reported function was assessed via the mJOA. Upper extremity function was measured via the fine motor skills (FiMS) tablet test. METHODS: Subjects and controls prospectively completed the mJOA paper survey and the FiMS tablet testing, which consisted of four challenges. RESULTS: After age-matching, 65 controls and 28 myelopathic patients were available for comparison. The mean mJOA was 13.5 ± 2.9 in the myelopathic cohort and 17.3 ± 1.1 in the control cohort (p < .0001). The average scores for challenges 1-4 in control patients were 24.4, 16.3, 3.2, and 6.6, respectively, whereas the average scores for the myelopathic patients were 16.6, 10.5, 1.4, and 1.8, respectively (p values for all four challenges <.001). Based upon the 15 control subjects who repeated FiMS testing four sequential times, intrarater reliability was excellent, yielding an interclass correlation coefficient of 0.88 CONCLUSIONS: The FiMS tablet application produced significantly lower scores in a myelopathic cohort when compared with an age-matched control cohort. This is true for all four challenges in the FiMS tablet application. The test can be completed in 1.5 minutes, producing a reliable, quantitative measure of cervical myelopathy upper extremity function. In summary, the FiMS tablet application is a novel, easily administered, objectively quantifiable test for analyzing cervical spondylotic myelopathy.

Structural Data Showing the Existence of LDI Bonds between the Rings of Dimeric Cofacial Siloxysilicon Phthalocyanines.

In a pair of earlier papers, the existence of long directional interaction bonds, LDI bonds, was postulated on the basis of data for cofacial oligomeric siloxysilicon phthalocyanines from this laboratory and data for other cofacial oligomeric phthalocyanines from the literature. However, the combined data are not fully suited to the purpose for which they were used. Here an alternative approach is taken in which a carefully chosen group of dimeric cofacial siloxysilicon phthalocyanines is used. Structural data derived from these phthalocyanines is examined in some detail to determine where it conforms to normal expectations and where it does not. To a high degree of certainty, consideration of the results obtained shows that long directional (LDI) bonds exist in dimeric cofacial siloxysilicon phthalocyanines. The new data also provide an opportunity for other research on chemical bonds.

Laser-induced ultrafast transport and demagnetization at the earliest time: first-principles and real-time investigation.

It is generally believed that there are at least two ways to use an ultrafast laser pulse to demagnetize a magnetic sample. One is to directly photo-demagnetize the system through spin-orbit coupling (SOC), and the other is to utilize ultrafast hot electron transport without SOC. The challenge is that these two processes are entangled on the same time scale. While the experimental results have been inconclusive, theoretical investigations are even scarcer, beyond those earlier studies based on spin superdiffusion. For instance, we do not even know how fast electrons move under laser excitation and how far they move. Here we carry out a first-principles time-dependent calculation to investigate how fast electrons actually move under laser excitation and how large the electron transport affects demagnetization on the shortest time scale. To take into account the transport effect, we implement the intraband transition in our theory. In the bulk fcc Ni, we find the effect of the spin transport on the demagnetization is extremely small, no more than 1%. The collective electron velocity in Ni is 0.4 Å fs-1, much smaller than the Fermi velocity, and the collective displacement is no more than 0.1 Å. But this does not mean that electrons do not travel fast; instead we find that electron velocities at two opposite crystal momenta cancel each other. We follow the Γ-X line and find a huge dispersion in the velocities in the crystal momentum space. In the Fe/W(1 1 0) thin film, the overall demagnetization is larger than Ni, and the Fermi velocity is higher than Ni. However, the effect of the spin transport is still small in the Fe/W(1 1 0) thin film. Based on our numerical results and existing experimental findings, we propose a different mechanism that can explain two latest experimental results. Our finding sheds new light on the effect of ballistic transport on demagnetization.

The Effect of Local Versus Intravenous Corticosteroids on the Likelihood of Dysphagia and Dysphonia Following Anterior Cervical Discectomy and Fusion: A Single-Blinded, Prospective, Randomized Controlled Trial.

BACKGROUND: Dysphagia and dysphonia are the most common postoperative complications following anterior cervical discectomy and fusion (ACDF). Although most postoperative dysphagia is mild and transient, severe dysphagia can have profound effects on overall patient health and on surgical outcomes. The purpose of this study was to compare the efficacy of local to intravenous (IV) steroid administration during ACDF on postoperative dysphagia and dysphonia. METHODS: This was a single-blinded, prospective, randomized clinical trial. Seventy-five patients undergoing ACDF with cervical plating were randomized into 3 groups: control (no steroid), IV steroid (10 mg of IV dexamethasone at the time of closure), or local steroid (40 mg of local triamcinolone). Patient-reported outcome measures (PROMs) were collected for dysphagia, dysphonia, and neck pain postoperatively for 1 year. RESULTS: Patient demographics were similar. Postoperative day 1 PROMs showed significantly lower scores for dysphonia (p = 0.015) and neck pain (p = 0.034) in the local steroid group. At 2 weeks postoperatively, the local steroid cohort showed significantly decreased prevalence of severe dysphagia (Eating Assessment Tool-10 [EAT-10], severe dysphagia, p = 0.027) compared with the control and IV steroid groups. Both steroid groups had significantly less severe dysphagia when compared with the control group at the 6-week and 3-month time points. At 1 year postoperatively, both steroid groups had significantly reduced dysphagia rates (p = 0.014) compared with the control group. CONCLUSIONS: Both local and IV steroid administration after cervical plating in ACDF yielded better PROMs for dysphagia compared with a control group. This finding is particularly evident in the reduced number of patients who reported severe dysphagia symptoms following ACDF with local steroid application within the first 2 postoperative weeks. Future studies should attempt to stratify dysphagia severity when reporting outcomes related to anterior cervical spine surgery. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Thoracolumbar Burst Fractures.

Thoracolumbar burst fractures are high-energy vertebral injuries, which commonly can be treated nonoperatively. Consideration of the injury pattern, extent of comminution, neurological status, and integrity of the posterior ligamentous complex may help determine whether operative management is appropriate. Several classification systems are contingent upon these factors to assist with clinical decision-making. A multitude of operative procedures have been shown to have good radiographic and clinical outcomes with extended follow-up, and treatment choice should be based on the individual's clinical and radiographic presentation.

The Effectiveness of Bioskills Training for Simulated Open Lumbar Laminectomy.

STUDY DESIGN: Randomized, prospective study within an orthopedic surgery resident program at a large urban academic medical center. OBJECTIVES: To develop an inexpensive, user-friendly, and reproducible lumbar laminectomy bioskills training module and evaluation protocol that can be readily implemented into residency training programs to augment the clinical education of orthopedic and neurosurgical physicians-in-training. METHODS: Twenty participants comprising senior medical students and orthopedic surgical residents. Participants were randomized to control (n = 9) or intervention (n = 11) groups controlling for level of experience (medical students, junior resident, or senior resident). The intervention group underwent a 40-minute bioskills training module, while the control group spent the same time with self-directed study. Pre- and posttest performance was self-reported by each participant (Physician Performance Diagnostic Inventory Scale [PPDIS]). Objective outcome scores were obtained from a blinded fellowship-trained attending orthopedic spine surgeon using Objective Structured Assessment of Technical Skills (OSATS) and Objective Decompression Score metrics. RESULTS: When compared with the control group, the intervention group yielded a significant mean improvement in OSATS (P = .022) and PPDIS (P = .0001) scores. The Objective Decompression Scores improved in the intervention group with a trend toward significance (P = .058). CONCLUSIONS: We conclude that a concise lumbar laminectomy bioskills training session can be a useful educational tool for to augment clinical education. Although no direct clinical correlation can be concluded from this study, the improvement in trainee's technical and procedural skills suggests that Sawbones training modules can be an efficient and effective tool for teaching fundamental spine surgical skills outside of the operating room.

Modeling and analysis of a meso-hydraulic climbing robot with artificial muscle actuation.

This paper presents a fully coupled electro-hydraulic model of a bio-inspired climbing robot actuated by fluidic artificial muscles (FAMs). This analysis expands upon previous FAM literature by considering not only the force and contraction characteristics of the actuator, but the complete hydraulic and electromechanical circuits as well as the dynamics of the climbing robot. This analysis allows modeling of the time-varying applied pressure, electrical current, and actuator contraction for accurate prediction of the robot motion, energy consumption, and mechanical work output. The developed model is first validated against mechanical and electrical data collected from a proof-of-concept prototype robot. The model is then employed to study the system-level sensitivities of the robot locomotion efficiency and average climbing speed to several design and operating parameters. The results of this analysis demonstrate that considering only the transduction efficiency of the FAM actuators is insufficient to maximize the efficiency of the complete robot, and that a holistic approach can lead to significant improvements in performance.

Management of Lumbar Conditions in the Elite Athlete.

Lumbar disk herniation, degenerative disk disease, and spondylolysis are the most prevalent lumbar conditions that result in missed playing time. Lumbar disk herniation has a good prognosis. After recovery from injury, professional athletes return to play 82% of the time. Surgical management of lumbar disk herniation has been shown to be a viable option in athletes in whom nonsurgical measures have failed. Degenerative disk disease is predominately genetic but may be accelerated in athletes secondary to increased physiologic loading. Nonsurgical management is the standard of care for lumbar degenerative disk disease in the elite athlete. Spondylolysis is more common in adolescent athletes with back pain than in adult athletes. Nonsurgical management of spondylolysis is typically successful. However, if surgery is required, fusion or direct pars repair can allow the patient to return to sports.

Iatrogenic Flatback and Flatback Syndrome: Evaluation, Management, and Prevention.

Flatback syndrome can be a significant source of disability, affecting stance and gait, and resulting in significant pain. Although the historical instrumentation options for thoracolumbar fusion procedures have been commonly regarded as the etiology of iatrogenic flatback, inappropriate selection, or application of modern instrumentation can similarly produce flatback deformities. Patients initially compensate with increased lordosis at adjacent lumbar segments and reduction of thoracic kyphosis. As paraspinal musculature fatigues and discs degenerate, maintaining sagittal balance requires increasing pelvic retroversion and hip extension. Ultimately, disc degeneration at adjacent levels overcomes compensatory mechanisms, resulting in sagittal imbalance and worsening symptoms. Nonoperative management for sagittally imbalanced (sagittal vertical axis>5 cm) flatback syndrome is frequently unsuccessful. Despite significant complication rates, surgical management to recreate lumbar lordosis using interbody fusions and/or osteotomies can significantly improve quality of life.

The Triangle Model of Congenital Cervical Stenosis.

STUDY DESIGN: Retrospective Cross-Sectional Study OBJECTIVE.: Identify the pathoanatomical features of the cervical spine associated with congenital stenosis SUMMARY OF BACKGROUND DATA.: Congenital cervical stenosis (CCS) describes a patient with a decreased spinal canal diameter at multiple levels of the cervical spine in the absence of degenerative changes. Despite recognition of CCS throughout the literature, the anatomical features that lead to this condition have not been established. Knowledge of the pathoanatomy behind CCS may lead to alterations in surgical technique for this patient population that may improve outcomes. METHODS: From 1000 cervical MRIs between January 2000 and December 2014, CCS was identified in 68 patients using a strict definition of age less than 50 years with mid-sagittal canal diameters (mid-SCD) (<10  mm) at multiple sub-axial cervical levels (C3-C7). A total of 68 patients met the inclusion criteria for this group. Fourteen controls with normal SCDs (>14  mm) at all cervical levels were used for comparison. Anatomic measurements obtained at each level (C3-C7) included: coronal vertebral body, AP vertebral body, pedicle width, pedicle length, laminar length, AP lateral mass, posterior canal distance, lamina-pedicle angle, and lamina-disc angle (LDA). Statistical significance was defined as P < 0.01. RESULTS: CCS patients demonstrated significantly different anatomical measurements when compared with controls. Significantly smaller lateral masses, lamina lengths, lamina-pedicle angles, and larger LDAs were identified at levels C3 to C7 in the CCS group (P < 0.01). These anatomic components form a right triangle that illustrates the cumulative narrowing effect on space for the spinal cord. CONCLUSION: The pathoanatomy of CCS is associated with a decrease in the lamina-pedicle angle and an increase in the LDA ultimately leading to a smaller SCD. The global changes in CCS are best illustrated by this triangle model and are driven by the posterior elements of the cervical spine. LEVEL OF EVIDENCE: 4.

Accessibility of the Cervicothoracic Junction Through an Anterior Approach: An MRI-based Algorithm.

STUDY DESIGN: Cross-sectional observational study. OBJECTIVE: To formulate a reliable method and modality for preoperative planning and to determine the effects of height, body mass index (BMI), and age on accessibility to the upper thoracic vertebrae through an anterior cervical approach. SUMMARY OF BACKGROUND DATA: Various modalities have been proposed to determine the lowest spinal-level accessible through a traditional anterolateral cervical approach and the consequent need for manubriotomy. Past methods have routinely involved a variety of imaging studies such as plain radiographs and computed tomography but the reliability of these methods has not been assessed. METHODS: The Magnetic Resonance Imaging (MRI) images of 180 patients classified by age and gender were evaluated and the most caudal accessible intervertebral disc space was determined from an approach angle beginning at the suprasternal notch. Plain cervical radiographs were also reviewed when available. In patients with multiple imaging studies, the reliability of the measurements was compared. Rate of accessibility was compared across different heights, BMIs, and ages. RESULTS: A novel algorithm that utilized both the scout and mid-sagittal T2 MRIs was able to determine the most caudal cervicothoracic level accessible for anterior access in 93.3% of patients with a reliability of 96.8%. Conversely, plain radiograph evaluation led to low reliability (66.7%) and low agreement with MRI (60%) with an average error of one spinal level. In this patient sample, the T1 to T2 disc space was accessible in 82.7% of patients. Age and BMI were independent variables associated with accessibility (p < 0.01) while height was determined not to be significant (p = 0.09). CONCLUSION: Data in this study suggest an MRI-based algorithm with a combination of scout and sagittal T2 images offers a reliable and consistent assessment of accessibility to upper thoracic levels through an anterior approach. Age and body mass index are major determinants of accessibility.