Christopher D. Witiw

Acute Spinal Cord Injury.

Our understanding of the pathophysiological processes that comprise the early secondary phases of spinal cord injury such as spinal cord ischemia, cellular excitotoxicity, ionic dysregulation, and free-radical mediated peroxidation is far greater now than ever before, thanks to substantial laboratory research efforts. These discoveries are now being translated into the clinical realm and have led to targeted upfront medical management with a focus on tissue oxygenation and perfusion and include avoidance of hypotension, induction of hypertension, early transfer to specialized centers, and close monitoring in a critical care setting. There is also active exploration of neuroprotective and neuroregenerative agents; a number of which are currently in late stage clinical trials including minocycline, riluzole, AC-105, SUN13837, and Cethrin. Furthermore, new data have emerged demonstrating that the timing of spinal cord decompression after injury impacts recovery and that early decompression leads to significant improvements in neurological recovery. With this review we aim to provide a concise, clinically relevant and up-to-date summary of the topic of acute spinal cord injury, highlighting recent advancements and areas where further study is needed.

Cerebral cavernous malformations and pregnancy: hemorrhage risk and influence on obstetrical management.

BACKGROUND Cerebral cavernous malformations are brain vascular malformations associated with intracranial hemorrhage. It is unclear whether pregnancy is a risk factor for hemorrhage, yet there is speculation that it may be. OBJECTIVE To compare the risk of clinically significant hemorrhage during pregnancy and nonpregnancy. METHODS A total of 186 patients from the University of Toronto Vascular Malformations Study Group were enrolled. The obstetrical history of each patient was collected and matched to their neurological history from the records of the study group. All hemorrhagic events occurring during childbearing years were associated with either a defined pregnancy risk period or nonpregnancy period. Patients were also asked to recall advice that they received from health care professionals regarding risk of hemorrhage in pregnancy. RESULTS Among our patient population there were 349 pregnancies (283 live births) and 49 hemorrhages during childbearing years, 3 of which were during pregnancy but none during delivery or within 6 weeks post partum. The hemorrhage rate for pregnant women was 1.15% (95% confidence interval: 0.23-3.35) per person-year and 1.01% (95% confidence interval: 0.75-1.36) per person-year for nonpregnant women. Relative risk of pregnancy was 1.13 (95% confidence interval: 0.34-3.75) (P = .84). Neurosurgeons and obstetricians were the source of most hemorrhage risk advice. The majority of neurosurgeons suggested that the risk was unchanged, but the obstetricians were divided. Four patients never conceived, and 2 others began contraception because of the advice that they received. CONCLUSION The risk of intracranial hemorrhage from cerebral cavernous malformations is likely not changed during pregnancy, delivery, or post partum.

Surgical treatment of spontaneous intracranial hypotension secondary to degenerative cervical spine pathology: a case report and literature review

Objective and importanceA rare cause of intracranial hypotension is leakage of cerebrospinal fluid (CSF) through a dural breach from degenerative cervical spine pathology. To our knowledge there have been only four cases described in the English literature. Treatment is challenging and varies from case to case, with complete symptom resolution reported for only one patient. Herein we review the literature and describe our surgical management of a 46-year-old woman with symptomatic intracranial hypotension from the penetration of the cervical thecal sac.Clinical presentation The patient presented with a 3-month history of progressive orthostatic headaches. Magnetic resonance imaging demonstrated bilateral subdural hematomas and pachymeningeal gadolinium enhancement. An anterior epidural CSF collection commencing at a C4–5 calcified disc protrusion and osteophyte was evident on a computed tomography spinal myelogram.InterventionAfter three unsuccessful lumbar blood patches, we elected to attempt surgical removal of the causative pathology with exposure and primary closure of the dural defect by anterior cervical discectomy as described previously. After resection of the disc–osteophyte complex and dural exposure, immediate high volume egression of CSF mixed with blood at the surgical site. The dural defect was not visible but CSF egression promptly ceased. Cervical corpectomy for greater exposure and primary repair of the defect has been described, but we considered this unwarranted and felt the intraoperative blood collection formed a local blood patch. A collagen dural substitute membrane was inserted through the discectomy space for reinforcement.Conclusion Two months after this novel surgical blood patch procedure the patient was asymptomatic and follow-up imaging demonstrated complete resolution.

Cervical Spine Clearance in Obtunded Patients After Blunt Traumatic Injury: A Systematic Review

Cervical spine trauma is a major public health problem and a common reason for admission to trauma wards and intensive care units. The cervical spine is injured in 2.3% to 4.3% (14) of blunt traumas. Resultant neurologic impairment is encountered in 33% to 54% (57) of patients with cervical spine trauma. In fact, more than 50% of all acute spinal cord injuries affect the cervical spine (8, 9). Unfortunately, these injuries have poor functional outcomes. Mortality after traumatic cervical spinal cord injury may exceed 20% (1013), and survivors often face lifelong physical disability, along with the associated emotional, psychological, and social burdens (6, 8, 14, 15). The economic costs of spinal cord injury are enormous. In the United States, the total annual direct cost of spinal cord injuries approaches

Sacral intradural arteriovenous fistula treated indirectly by transection of the filum terminale: technical case report.

8 billion (16). These factors make diligent and efficient cervical spine clearance protocols a critical priority. The exclusion of cervical spine injury in obtunded patients with trauma poses a significant challenge given the lack of a reliable clinical examination. Common practices at many trauma centers include routine acquisition of cervical spine magnetic resonance imaging (MRI), dynamic radiography (flexion and extension), or continued cervical immobilization until patients are awake and asymptomatic after a negative computed tomography (CT) scan (17, 18). These protocols may increase health care costs unduly, place critically ill patients at risk for deterioration during transportation, and prolong cervical collar immobilization and its associated illnesses. On the other hand, the consequences of missing an injury can be devastating and may include loss of functional ability, independence, and possibly life (1921). The primary aim of this study was to elucidate the role for further routine imaging or prolonged cervical immobilization in excluding significant cervical spine injury after negative CT results in obtunded patients who had blunt traumatic injury. Methods This systematic review was done according to a predefined protocol (Supplement) in accordance with MOOSE (Meta-analysis Of Observational Studies in Epidemiology) guidelines (22) and the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) Statement (23). Supplement. Study Protocol Search Strategy We searched MEDLINE (PubMed and Ovid), EMBASE, CINAHL, Google Scholar, and the Cochrane Library from January 2000 through November 2014 for studies on the role of CT followed by a validating test in evaluating the cervical spine of obtunded trauma patients. We used, in various combinations, keywords and Medical Subject Headings terms pertinent to the patient population (altered, comatose, intensive care, intubated, mental status, obtunded, unconscious, unevaluable, unexaminable, unreliable, or unresponsive), medical condition (fracture, injury, instability, or trauma), anatomical site of interest (cervical-spine or cervical), and relevant radiological imaging methods (clearance, computed tomography, CT, dynamic, extension, flexion, fluoroscopy, imaging, magnetic resonance, MDCT, MR, MRI, plain film, radiograph, or X-ray). We also manually searched the references of relevant studies to identify additional studies for consideration. Selection Criteria Three investigators independently evaluated the studies for eligibility. Selection criteria included a study of any design (randomized, controlled trial; prospective cohort study; or retrospective cohort study). Studies were eligible if the diagnostic protocol of interest included a negative finding on a helical CT scan of the entire cervical spine followed by a confirmatory test. We included only the population of obtunded patients with blunt trauma (Glasgow Coma Scale [GCS] score 14, unreliable clinical examination, or intubation). Only English-language studies documenting the outcome measures of missed cervical spine injury or intervention after a negative CT result and additional findings of a validating test were included. We excluded studies with a sample size of fewer than 10 patients and studies in which partial cervical spine CT scans were used. For studies reporting data on overlapping cohorts from the same institution, we included only the study with the most inclusive cohort to prevent duplication. Studies evaluating only the pediatric population were excluded. Studies that examined awake and obtunded patients were included only if the outcomes of unreliable patients were analyzed separately. Abstracts from meeting proceedings were excluded if the data were not published in full-text articles in a peer-reviewed journal. Disagreements among the 3 reviewers about the decision to include or exclude a study were resolved by consensus and, if necessary, consultation with a fourth reviewer. Data Extraction and Quality Assessment Data from eligible studies were independently extracted by the 3 primary reviewers and verified for accuracy by the fourth reviewer. Discrepancies were resolved by discussion and consensus. We used data collection forms that included the following fields: title, author, year and country of publication, study design, sample size, patient demographic characteristics, Injury Severity Score, GCS score, definition of obtunded, mechanism of injury, CT specifications, further imaging or follow-up of patients with negative CT scans, image interpreter, missed acute cervical spine injuries, and changes in management. The 3 primary reviewers performed quality assessment independently. We used the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies-2) tool (24) and examined patient selection, the index test and reference standard used, and flow and timing to determine whether the risk of bias and concerns about applicability to the review question were low, unclear, or high among eligible studies. Definition of Variables Our primary outcome of interest was clinically significant cervical spine injury missed by CT and detected by the confirmatory test. A clinically significant injury was defined as one resulting in mechanical instability or requiring intervention or change in management. We excluded soft tissue signal changes that did not affect spine stability. The definition of cervical spine instability varied among included studies and was assessed by using many classification systems. Most eligible studies defined instability in accordance with the work of White and Panjabi (25) on biomechanics of the spine. Previous studies defined unstable and purely ligamentous injuries as those involving all 3 columns (26). We adopted and documented cervical spine instability outcomes as reported by the authors of included studies, regardless of the classification used. Changes in management after negative CT results and positive findings on a validating test included prolonged external immobilization or operative stabilization. An obtunded patient was defined as someone who was not fully awake and had an altered level of consciousness (GCS 14). These patients lacked a reliable neurologic examination that could aid in the diagnosis of spinal injury. High-quality CT scans were defined as those protocolled with narrow slice width (1 to 3 mm) and reconstruction in multiple planes. A well-interpreted CT study was defined as an image read by a health professional with special training and expertise in reading such images (that is, a consultant radiologist) rather than an on-call physician or radiology resident. Data Synthesis and Analysis Studies were grouped on the basis of how further evaluation of obtunded trauma patients with negative results from cervical spine CT was handled. The first group included studies that routinely performed MRI after a CT scan that was interpreted as normal. The second group comprised studies in which patients were routinely evaluated with dynamic radiography after negative CT results. The third group included studies in which patients were followed with serial physical examination after a normal CT result, with further imaging obtained as guided by clinical indications (for example, neurologic deficit). For each group, we examined mechanical cervical spine instability, need for operative stabilization, and collar use after negative CT results and additional findings on the confirmatory test. We examined high-quality studies separately. These reports fulfilled 4 criteria: prospective study design, low risk of bias and low concerns about applicability in all domains on the QUADAS-2 tool, well-interpreted CT images, and use of high-quality CT specifications. Given the small number of events (if any), formal meta-analysis was not possible. Data from individual studies are displayed in forest plots with 95% CIs. Exact binominal 1-sided 95% CIs were calculated for each proportion obtained from eligible studies (27). We used R, version 3.1.2 (R Foundation for Statistical Computing), to generate all forest plots. Role of the Funding Source This study received no funding. Results Characteristics of Included Studies Our search yielded 2112 results, of which 1959 were excluded after title and abstract screening. Another 125 were excluded after full-text review (Appendix Figure). The remaining 28 studies (2855) were included, and they reported on a total of 3627 obtunded blunt trauma patients with negative results from cervical spine CT and a validating test. Twenty studies (28, 29, 32, 34, 35, 37, 4044, 46, 4855) were retrospective cohort studies, and 8 (30, 31, 33, 36, 38, 39, 45, 47) were prospective cohort studies. Descriptions of eligible studies are provided in Appendix Tables 1 and 2. Details of methodological assessment of included studies with the QUADAS-2 tool are presented in Appendix Table 3. Appendix Figure. Summary of evidence search and selection. CT = computed tomography. Appendix Table 1. Characteristics of Included Studies Appendix Table 2. Outcomes of Eligible Studies Appendix Table 3. Quality Assessment of Eligible Studies Wit

Deep brain stimulation for Parkinson’s disease: meta-analysis of results of randomized trials at varying lengths of follow-up

BACKGROUND AND IMPORTANCE:Type A intradural arteriovenous fistulae of the sacral filum terminale are rare lesions fed primarily by the distal anterior spinal artery. The artery is frequently too narrow or tortuous for endovascular obliteration, and direct surgical resection of the fistula requires an invasive sacrectomy. We present a less invasive indirect surgical approach through an L4 laminectomy and transection of the filum terminale rostral to the fistula. CLINICAL PRESENTATION:A 62-year-old man presented with a 6-month history of progressive bilateral lower extremity paresthesias and weakness and associated incontinence and impotence. Spinal magnetic resonance imaging demonstrated perimedullary flow voids. Selective spinal angiography revealed a fistula at S2-3 between the distal anterior spinal artery and an early draining vein returning cranially along the filum terminale, diagnostic of an intradural arteriovenous fistula. An L4 laminectomy and transection of the filum terminale rostral to the lesion were performed to disrupt the medullary arterial supply to the intradural fistula and outflow to the medullary venous plexus of the spinal cord. At 10-month clinical follow, up the patient had regained bowel and bladder continence, was able to ambulate with a cane, and reported subjective improvement of lower extremity paresthesias. Selective spinal angiography at 1 year demonstrated no residual arteriovenous shunt. CONCLUSION:Pathological venous hypertension of a type A intradural arteriovenous fistula of the sacral filum terminale can be treated by transection of the filum terminale at L4. This avoids posterior partial sacrectomy required for direct resection; however, subsequent clinical follow-up is necessary to monitor for reconstitution.

Economics, innovation, and quality improvement in neurosurgery.

OBJECTIVE Deep brain stimulation (DBS) is effective in the management of patients with advanced Parkinsons disease (PD). While both the globus pallidus pars interna (GPi) and the subthalamic nucleus (STN) are accepted targets, their relative efficacy in randomized controlled trials (RCTs) has not been established beyond 12 months. The objective of this study was to conduct a meta-analysis of RCTs to compare outcomes among adults with PD undergoing DBS of GPi or STN at various time points, including 36 months of follow-up. METHODS The MEDLINE, Embase, CENTRAL, Web of Science, and CINAHL databases were searched. Registries for clinical trials, selected conference proceedings, and the table of contents for selected journals were also searched. Screens were conducted independently and in duplicate. Among the 623 studies initially identified (615 through database search, 7 through manual review of bibliographies, and 1 through a repeat screen of literature prior to submission), 19 underwent full-text review; 13 of these were included in the quantitative meta-analysis. Data were extracted independently and in duplicate. The Cochrane Collaboration tool was used to assess the risk of bias. The GRADE evidence profile tool was used to assess the quality of the evidence. Motor scores, medication dosage reduction, activities of daily living, depression, dyskinesias, and adverse events were compared. The influence of disease duration (a priori) and the proportion of male patients within a study (post hoc) were explored as potential subgroups. RESULTS Thirteen studies (6 original cohorts) were identified. No difference in motor scores or activities of daily living was identified at 36 months. Medications were significantly reduced with STN stimulation (5 studies, weighted mean difference [WMD] -365.46, 95% CI -599.48 to -131.44, p = 0.002). Beck Depression Inventory scores were significantly better with GPi stimulation (3 studies; WMD 2.53, 95% CI 0.99-4.06 p = 0.001). The motor benefits of GPi and STN DBS for PD are similar. CONCLUSIONS The motor benefits achieved with GPi and STN DBS for PD are similar. DBS of STN allows for a greater reduction of medication, but not as significant an advantage as DBS of GPi with respect to mood. This difference is sustained at 36 months. Further long-term studies are necessary.

Exploring the expectation-actuality discrepancy: a systematic review of the impact of preoperative expectations on satisfaction and patient reported outcomes in spinal surgery.

Innovation to improve patient care quality is a priority of the neurosurgical specialty since its beginnings. As the strain on health care resources increases, the cost of these quality improvements is becoming increasingly important. The aims of this article are to review the available tools for assessing the cost of quality improvement along with the willingness to pay and to provide a conceptual framework for the assessment of innovations in terms of quality and economic metrics and provide examples from the neurosurgical literature.

A novel device to simplify intraoperative radiographic visualization of the cervical spine by producing transient caudal shoulder displacement: a 2-center case series of 80 patients.

Quality in healthcare is increasingly graded through a patient-centric lens, using reports of satisfaction and self-perceived outcome. Preestablished expectations have been recognized to influence these measures. With this review, we aim to examine the impact of expectations on satisfaction and patient-reported outcomes (PRO) for individuals undergoing elective spine surgery. We systematically searched MEDLINE, EMBASE, CINAHL, and Cochrane Library electronic databases from inception to July 2015 for studies examining the relationship between expectations and satisfaction/PROs in the context of elective spinal surgery. Qualitative synthesis centered around three key questions: (1) Does the magnitude of preoperative expectations impact patient satisfaction and/or PRO after surgery? (2) Does the underlying spinal pathology influence this relationship? (3) What is the impact of unmet expectations on satisfaction? A total of 1489 citations were retrieved. Nineteen met our inclusion criteria. These comprised 3383 patients; 3200 had lumbar and only 183 had cervical spine surgery. Three findings prevailed: (1) high preoperative expectations appear to be associated with higher satisfaction and PROs after surgery for focal lumbar disc herniation, but not for lumbar spinal stenosis; (2) patient expectations frequently exceed actual outcome, creating an “expectation-actuality discrepancy” (E-AD); and (3) high-quality studies suggest a larger E-AD portends lower satisfaction. Limitations to the data include heterogeneous study populations and surgical indications, along with the use of non-validated assessment tools, particularly for satisfaction. Our findings highlight the potential importance of establishing realistic expectations prior to surgery and may serve to direct future research efforts.

Spontaneous Intracranial Hypotension: A Review and Introduction of an Algorithm For Management

OBJECT Intraoperative radiographic localization within the cervical spine can be a challenge because of the anatomical relation of the musculoskeletal structures of the pectoral girdle. On standard cross-table lateral radiographs, these structures can produce shadowing that obscure the anatomical features of the cervical vertebrae, particularly at the caudal levels. Surgical guidelines recommend accurate intraoperative localization as a means to reduce wrong-level spine surgery, and unobstructed visualization is needed for fluoroscopy-guided placement of spinal instrumentation. In this article, the authors describe and evaluate a novel device designed to provide transient intraoperative caudal displacement of the shoulders to improve and simplify radiographic visualization of the cervical spine. METHODS A 2-center prospective study was conducted to evaluate the device. The study included a total of 80 patients undergoing cervical spine surgery. The device was evaluated in a cohort of 50 patients undergoing elective single-level anterior discectomy and fusion and also in a second cohort of 30 patients at an independent institution. The patients in this second cohort were undergoing a variety of cervical spine procedures for multiple indications and were included in the study to allow the authors to assess the effectiveness of the device in a general neurosurgical practice. After the patients were anesthetized and positioned, consecutive standard cross-table lateral radiographs or intraoperative fluoroscopic were obtained before and after use of the device. The images were compared in order to determine the difference in lowest vertebral level visible. RESULTS There was an average difference in cervical spine visualization of +2.8 ± 0.9 vertebral levels in the first cohort, while in the second the improvement was +1.2 ± 0.7 levels (p < 0.0001 between cohorts, unpaired t-test). There was one complication, a minor shoulder abrasion, which required no specific management. CONCLUSIONS This device is safe and effective for increasing the radiographic visualization of the cervical spine for intraoperative localization.