Anick Nater

Survival and Clinical Outcomes in Surgically Treated Patients With Metastatic Epidural Spinal Cord Compression: Results of the Prospective Multicenter AOSpine Study

PURPOSE Although surgery is used increasingly as a strategy to complement treatment with radiation and chemotherapy in patients with metastatic epidural spinal cord compression (MESCC), the impact of surgery on health-related quality of life (HRQoL) is not well established. We aimed to prospectively evaluate survival, neurologic, functional, and HRQoL outcomes in patients with MESCC who underwent surgical management. PATIENTS AND METHODS One hundred forty-two patients with a single symptomatic MESCC lesion who were treated surgically were enrolled onto a prospective North American multicenter study and were observed at least up to 12 months. Clinical data, including Brief Pain Inventory, ASIA (American Spinal Injury Association) impairment scale, SF-36 Short Form Health Survey, Oswestry Disability Index, and EuroQol 5 dimensions (EQ-5D) scores, were obtained preoperatively, and at 6 weeks and 3, 6, 9, and 12 months postoperatively. RESULTS Median survival time was 7.7 months. The 30-day and 12-month mortality rates were 9% and 62%, respectively. There was improvement at 6 months postoperatively for ambulatory status (McNemar test, P < .001), lower extremity and total motor scores (Wilcoxon signed rank test, P < .001), and at 6 weeks and 3, 6, and 12 months for Oswestry Disability Index, EQ-5D, and pain interference (paired t test, P < .013). Moreover, at 3 months after surgery, the ASIA impairment scale grade was improved (Stuart-Maxwell test P = .004). SF-36 scores improved postoperatively in six of eight scales. The incidence of wound complications was 10% and 2 patients required a second surgery (screw malposition and epidural hematoma). CONCLUSION Surgical intervention, as an adjunct to radiation and chemotherapy, provides immediate and sustained improvement in pain, neurologic, functional, and HRQoL outcomes, with acceptable risks in patients with a focal symptomatic MESCC lesion who have at least a 3 month survival prognosis.

Risk Factors for Recurrence of Surgically Treated Conventional Spinal Schwannomas: Analysis of 169 Patients From a Multicenter International Database.

Study Design. A retrospective analysis of 169 adult patients operated for a conventional spinal schwannoma from the AOSpine Multicenter Primary Spinal Tumors Database. Objective. The aim of this study is to identify risk factors for local recurrence of conventional spinal schwannoma in patients who had surgery. Summary of Background Data. Schwannomas account for up to 30% of all adult spinal tumors. Total resection is the gold standard for patients with sensory or motor deficits. Local recurrence is reported to be approximately 5% and usually occurs several years after surgery. Methods.. Rates and time of local recurrence of spinal schwannoma were quantified. Predictive value of various clinical factors was assessed, including age, gender, tumor size, affected spinal segment, and type of surgery. Descriptive statistics and univariate regression analyses were performed. Results. Nine (5.32%) out the 169 patients in this study experienced local recurrence approximately 1.7 years postoperatively. Univariate analyses revealed that recurrence tended to occur more often in younger patients (39.33 ± 14.58 versus 47.01 ± 15.29 years) and in the lumbar segment (55.56%), although this did not reach significance [hazard ratio (HR) 0.96, P = 0.127; and P = 0.195, respectively]. Recurrence also arose in the cervical and sacral spine (22.22%, respectively) but not in the thoracic area. Tumors were significantly larger in patients with recurrence (6.97 ± 4.66 cm versus 3.81 ± 3.34 cm), with extent in the cranial caudal direction posing the greatest hazard (HR = 1.321, P = 0.002). The location of the tumor, whether epidural, intradural, or both (P = 0.246), was not significantly related to recurrence. Regarding surgical technique, over 4 times as many patients who underwent intralesional resection experienced a recurrence proportionally to patients who underwent en bloc resection (HR = 4.178, P = 0.033). Conclusion. The pre-operative size of the conventional spinal schwannoma and intralesional resection are the main risk factors for local postoperative recurrence. Level of Evidence: 3

Cost-effectiveness of surgery in the management of metastatic epidural spinal cord compression: a systematic review.

Study Design. Systematic review. Objective. To perform an evidence-based synthesis of the literature to examine the cost-effectiveness of surgery in the management of metastatic epidural spinal cord compression (MESCC). Summary of Background Data. Between 2.5% and 10% of patients with cancer develop symptomatic MESCC, which leads to significant morbidity, and a reduction in quality and length of life. Although surgery is being increasingly used in the management of MESCC, it is unclear whether this modality is cost-effective, given the relatively limited lifespan of these patients. Methods. Numerous databases were searched to identify full economic studies based on key questions established a priori. Only economic studies that evaluated and synthesized the costs and consequences (i.e., cost-minimization, cost-benefit, cost-effectiveness, or cost-utility) were considered for inclusion. Two independent reviewers examined the full text of the articles meeting inclusion criteria to obtain the final cohort of included studies. The Quality of Health Economic Studies instrument was scored by 2 independent reviewers. Results. The search strategy yielded 38 potentially relevant citations, 2 of which met the inclusion criteria. One was a cost-utility study and the other was a cost-effectiveness study, and both used clinical data from the same randomized controlled trial. Both studies found surgery plus radiotherapy to be not only more expensive but also more effective than radiotherapy alone in the management of patients with MESCC. Conclusion. There is evidence from 2 high-quality studies that surgery plus radiotherapy is costlier but clinically more effective than radiotherapy alone for the management of MESCC. Of note, cost-effectiveness data for the role of spinal stabilization in the management of oncological spinal instability are lacking. This is a key knowledge gap that represents an opportunity for future research.

MRI analysis of the combined prospectively collected AOSpine North America and International Data: The Prevalence and Spectrum of Pathologies in a Global Cohort of Patients with Degenerative Cervical Myelopathy

Study Design. An ambispective analysis. Objective. The aim of this study was to report the global prevalence of specific degenerative cervical pathologies in patients with degenerative cervical myelopathy (DCM) through detailed review of magnetic resonance imaging (MRIs). Summary of Background Data. DCM encompasses a spectrum of age-related conditions that result in progressive spinal cord injury. Methods. MRIs of 458 patients (age 56.4 ± 11.8, 285 male, 173 female) were reviewed for specific degenerative features, directionality of cord compression, levels of spinal cord compression, and signal changes on sagittal T2-weighted imaging (T2WI) and sagittal T1-weighted imaging (T1WI). Data were analyzed for differences between sex using Chi-square tests and geographic variations using Kruskal-Wallis tests. Results. Spondylosis was frequently present (89.7%) and was commonly accompanied by enlargement of the ligamentum flavum (LF) (59.9%). Single-level disc pathology, ossification of posterior longitudinal ligament (OPLL), and spondylolisthesis had a prevalence of ∼10% each. OPLL was accompanied by spondylosis in 91.7%. Klippel-Feil syndrome was observed in 2.0%. The Asia-Pacific region had more OPLL (29%, P = 3 × 10−11) and less spondylolisthesis (1.9%, P = 0.002). Females presented more commonly with single-level disc pathology (13.9% vs. 6.7%; P = 0.013), and males with spondylosis (92.3% vs. 85.6%; P = 0.02) and enlargement of LF (61.4% vs. 49.1%; P = 0.01). C5 to C6 was the most frequent maximum compressed site (39.5%) and region for T2WI hyperintensity (38.9%). T2WI hyperintensity more commonly presented in males (82.4% vs. 66.7%; P < 0.001). Conclusion. This is the largest report on the prevalence and spectrum of pathology in patients with DCM. Herein, it has been demonstrated that degenerative features are highly interrelated, that females presented with milder MRI evidence of DCM, and that variations exist in the prevalence of pathologies between geographical regions. Level of Evidence. 2

Changing the adverse event profile in metastatic spine surgery: An evidence based approach to target wound complications and instrumentation failure

Study Design. Systematic review. Objective. To identify risk factors and preventive methods for wound complications and instrumentation failure after metastatic spine surgery. Summary of Background Data. We focused on two postoperative complications of metastatic spine tumor surgery: wound complications and instrumentation failure and preventive measures. Methods. We performed a systematic review of the literature from 1980 to 2015. The articles were analyzed for the presence of documented infection and/or wound complications and instrumentation failure. Results. Forty articles met our inclusion criteria for wound complications and prevention. There is very low level of evidence that preoperative radiation, preoperative neurological deficit, revision procedures, and posterior approaches can contribute to wound complications (infections, wound dehiscence). There is very low level of evidence that plastic surgery soft tissue reconstruction, intrawound vancomycin powder, and percutaneous pedicle screws may prevent postoperative wound complications. Fourteen articles met our inclusion criteria for instrumentation failure. There is very low level of evidence that constructs greater than six levels, positive sagittal balance, preoperative radiation, and history of chest wall resection can contribute to implant failures. Conclusion. • For patients undergoing revision metastatic spine tumor surgery, plastic surgery should perform the soft tissue reconstruction (strong recommendation/very low quality of evidence). • For patients undergoing metastatic spine tumor surgery, plastic surgery may perform immediate soft tissue reconstruction (weak recommendation/very low quality of evidence). • For patients undergoing metastatic spine tumor surgery, intrawound vancomycin can be applied to decrease the risk of postoperative wound infections (weak recommendation/very low quality of evidence). • For patients undergoing metastatic spine tumor surgery, percutaneous pedicle screws can be placed to decrease the risk of postoperative wound complications (weak recommendation/very low quality of evidence). • Instrumentation failure risk factors include constructs greater than six levels, positive sagittal balance, preoperative radiation, and history of chest wall resections (weak recommendation/very low quality of evidence). Level of Evidence: N/A

316 Magnetic Resonance Imaging Analysis of the Combined AOSpine North America and International Studies, Part I: The Prevalence and Spectrum of Pathologies in a Global Cohort of Patients With Degenerative Cervical Myelopathy

INTRODUCTION Degenerative cervical myelopathy (DCM) encompasses a spectrum of age-related conditions that result in progressive spinal cord injury through static and dynamic injury mechanisms. Through detailed review of MRIs from prospective AOSpine multicenter studies, the global prevalence of degenerative cervical pathologies of surgically treated DCM patients is reported. METHODS MRIs of 458 patients were obtained from North America (n = 197), Europe (n = 92), Latin America (n = 57), and Asia-Pacific (n = 112) and assessed for the type of pathology, source of stenosis, level of maximum cord compression, levels of spinal cord compression (SCC), presence of signal changes on T2-weighted images (T2WI) and T1-weighted images, and the levels of T2WI signal change. The proportion of degenerative changes present alongside other diagnoses was computed as well as the prevalence of pathologies per geographical region. The prevalence of degenerative changes was separated by sex and assessed using χ analysis. RESULTS Spondylosis was the most frequent cause of SCC (89.7%) and it was frequently accompanied by enlargement of the ligamentum flavum (59.85%). Ossification of the posterior longitudinal ligament (OPLL) was accompanied by spondylosis in 91.7%. Single-level disc pathology, OPLL, and spondylolisthesis had a prevalence of ∼10%. Klippel-Feil syndrome was observed in 2.8%. Single-level pathology was less common in North America, and OPLL was more common and spondylolisthesis less common in Asia-Pacific. Females presented more commonly with single-level disc pathology (P = .013), and males with spondylosis (P = .017) and enlargement of ligamentum flavum (P = .012). Globally, C5-6 was the most frequent maximum compressed site (39.7%) and region for T2WI hyperintensity (38.9%). T2WI hyperintensity more commonly presented in males (P < .001). CONCLUSION DCM pathologies, including OPLL, are highly interrelated and rarely present in isolation. Females presented with milder evidence of DCM on MRI. There are also variances in the spectrum and prevalence of pathologies between geographical regions and these may be due to a multitude of causes.

The Timing of Decompressive Spinal Surgery in Cauda Equina Syndrome

uring their lifetime, 80% of people experience low back pain. It is one of the most common chief complaints for D people seeking medical attention in the ambulatory care setting (1). Although cauda equina syndrome (CES) causes severe low back pain in <1 of 2000 patients (9), it is the source of considerable controversy. CES is a poorly characterized clinical entity associated with potentially significant distressing and disabling permanent neurologic deficits for which the timing of surgical intervention is still a matter of debate. This controversy is amplified by the fact that cases of CES are often the subject of litigation with a high medicolegal and health care cost profile. Given these issues, the systematic review of the timing of surgical intervention in CES by Chau et al. in the March/April issue of WORLD NEUROSURGERY is particularly timely.

Necrotizing Infundibuloneurohypophysitis: Case Report and Literature Review

Several conditions may lead to pituitary necrosis: Sheehan syndrome, increased intracranial pressure, traumatic pituitary injury, thrombosis of the vessels perfusing the pituitary, ischemia, as well as various infections and autoimmune processes. Necrosis may develop in the anterior and posterior lobes, as well as in the pituitary stalk and infundibulum. Hypophysitis is a chronic inflammatory disorder resulting from an autoimmune process (primary hypophysitis) [1, 2] or from an identified agent, such as infection (secondary hypophysitis) [3]. By histology, in various forms of hypophysitis, necrotic areas may be apparent. Necrosis is usually small and focal in primary hypophysitis [4]. To date, to our knowledge, there are only a few published cases where necrosis occupied large portions of the hypophysis [4, 5]. We report the case of a 13-year-old female with central diabetes insipidus (DI) and hypopituitarism. Magnetic resonance imaging (MRI) showed homogeneous gadolinium enhancement in the upper pituitary stalk and on the floor of the third ventricle. The lesion was surgically removed. The histologic, immunohistochemical, and electron microscopic examinations of the surgical specimen revealed necrotizing infundibuloneurohypophysitis.

Symptomatic spinal metastasis: A systematic literature review of the preoperative prognostic factors for survival, neurological, functional and quality of life in surgically treated patients and methodological recommendations for prognostic studies

Purpose While several clinical prediction rules (CPRs) of survival exist for patients with symptomatic spinal metastasis (SSM), these have variable prognostic ability and there is no recognized CPR for health related quality of life (HRQoL). We undertook a critical appraisal of the literature to identify key preoperative prognostic factors of clinical outcomes in patients with SSM who were treated surgically. The results of this study could be used to modify existing or develop new CPRs. Methods Seven electronic databases were searched (1990–2015), without language restriction, to identify studies that performed multivariate analysis of preoperative predictors of survival, neurological, functional and HRQoL outcomes in surgical patients with SSM. Individual studies were assessed for class of evidence. The strength of the overall body of evidence was evaluated using GRADE for each predictor. Results Among 4,818 unique citations, 17 were included; all were in English, rated Class III and focused on survival, revealing a total of 46 predictors. The strength of the overall body of evidence was very low for 39 and low for 7 predictors. Due to considerable heterogeneity in patient samples and prognostic factors investigated as well as several methodological issues, our results had a moderately high risk of bias and were difficult to interpret. Conclusions The quality of evidence for predictors of survival was, at best, low. We failed to identify studies that evaluated preoperative prognostic factors for neurological, functional, or HRQoL outcomes in surgical patients with SSM. We formulated methodological recommendations for prognostic studies to promote acquiring high-quality evidence to better estimate predictor effect sizes to improve patient education, surgical decision-making and development of CPRs.

Development and Implementation of Guidelines in Neurosurgery

Although it is intuitive that any neurosurgeon would seek to consistently apply the best available evidence to patient management, the application of evidence-based medicine (EBM) principles and clinical practice guidelines (CPGs) remains variable. This article reviews the origin and process of EBM, and the development, assessment, and applicability of EBM and CPGs in neurosurgical care, aiming to demonstrate that CPGs are one of the valid available options that exist to improve quality of care. CPGs are not intended to define the standard of care but to compile dynamic advisory statements, which need to be updated as new evidence emerges.