Loss of consciousness at onset of aneurysmal subarachnoid hemorrhage in good-grade patients.

Loss of consciousness (LOC) at presentation with aneurysmal subarachnoid hemorrhage (aSAH) has been associated with early brain injury and poor functional outcome. The impact of LOC on the clinical course after aSAH deserves further exploration. A retrospective analysis of 149 aSAH patients who were prospectively enrolled in the Cerebral Aneurysm Renin Angiotensin Study (CARAS) between 2012 and 2015 was performed. The impact of LOC was analyzed with emphasis on patients presenting in excellent or good neurological condition (Hunt and Hess 1 and 2). A total of 50/149 aSAH patients (33.6%) experienced LOC at presentation. Loss of consciousness was associated with severity of neurological condition upon admission (Hunt and Hess, World Federation of Neurosurgical Societies (WFNS), Glasgow Coma Scale (GCS) grade), hemorrhage burden on initial head CT (Fisher CT grade), acute hydrocephalus, cardiac instability, and nosocomial infection. Of Hunt and Hess grade 1 and 2 patients, 21/84 (25.0%) suffered LOC at presentation. Cardiac instability and nosocomial infection were significantly more frequent in these patients. In multivariable analysis, LOC was the predominant predictor of cardiac instability and nosocomial infection. Loss of consciousness at presentation with aSAH is associated with an increased rate of complications, even in good-grade patients. The presence of LOC may identify good-grade patients at risk for complications such as cardiac instability and nosocomial infection.

Current Topics in the Management of Acute Traumatic Spinal Cord Injury.

Acute traumatic spinal cord injury (SCI) affects more than 250,000 people in the USA, with approximately 17,000 new cases each year. It continues to be one of the most significant causes of trauma-related morbidity and mortality. Despite the introduction of primary injury prevention education and vehicle safety devices, such as airbags and passive restraint systems, traumatic SCI continues to have a substantial impact on the healthcare system. Over the last three decades, there have been considerable advancements in the management of patients with traumatic SCI. The advent of spinal instrumentation has improved the surgical treatment of spinal fractures and the ability to manage SCI patients with spinal mechanical instability. There has been a concomitant improvement in the nonsurgical care of these patients with particular focus on care delivered in the pre-hospital, emergency room, and intensive care unit (ICU) settings. This article represents an overview of the critical aspects of contemporary traumatic SCI care and notes areas where further research inquiries are needed. We review the pre-hospital management of a patient with an acute SCI, including triage, immobilization, and transportation. Upon arrival to the definitive treatment facility, we review initial evaluation and management steps, including initial neurological assessment, radiographic assessment, cervical collar clearance protocols, and closed reduction of cervical fracture/dislocation injuries. Finally, we review ICU issues including airway, hemodynamic, and pharmacological management, as well as future directions of care.

The role of endothelial nitric oxide synthase -786 T/C polymorphism in cardiac instability following aneurysmal subarachnoid hemorrhage.

INTRODUCTION: Cardiac abnormalities are observed frequently after aneurysmal subarachnoid hemorrhage (aSAH). A subset of aSAH patients develops neurogenic cardiomyopathy, likely induced by catecholamine excess. Genetic polymorphisms of the endothelial nitric oxide synthase (eNOS) gene have been linked to decreased nitric oxide (NO) levels, coronary artery spasm, and myocardial infarction. The role of the eNOS single nucleotide polymorphism (SNP) -786 T/C in cardiac instability following aSAH has not been previously investigated. METHODS: From 2012 to 2015, aSAH patients were prospectively enrolled in the Cerebral Aneurysm Renin Angiotensin System (CARAS) study at two academic institutions. Blood samples were used to assess the eNOS SNP -786 T/C rs2070744 through 5'exonuclease (Taqman) genotyping assays. Associations between this polymorphism and cardiac instability following aSAH were analyzed. RESULTS: Multivariable analysis demonstrated a dominant effect of the C allele of eNOS SNP -786 T/C on cardiac instability in patients with aSAH. A lower Glasgow Coma Scale score and a history of ischemic vascular disease were also associated with cardiac instability. Furthermore, cardiac instability independently predicted poor functional outcome upon discharge from the hospital. CONCLUSIONS: The C allele of the eNOS SNP -786 T/C was independently associated with an increased risk for cardiac instability following aSAH. Cardiac instability itself was a risk factor for an unfavorable functional outcome upon discharge from the hospital.

Assessment of driving outcomes after epilepsy surgery.

INTRODUCTION: Driving is an important factor contributing to good quality of life in patients with epilepsy. Little work has been undertaken to explore the details of driving experience alone in this patient population. We assessed the driving status of our patients prior to and following surgery for epilepsy. We also sought to determine what associations exist between patient characteristics and postoperative driving status. METHODS: The participants were selected from those adult patients with epilepsy who have required surgical treatment at our home institution between 2006 and 2010. Each participant received a questionnaire asking about driving and seizure status before and after surgery. The surveys were distributed using a modified Dillman approach. Perioperative patient data were obtained from the electronic medical record system in addition to a previously assembled epilepsy database from the Neurology Department at our institution. Independent variables were analyzed to look for significant associations with driving outcomes. RESULTS: One hundred forty eligible patients were included in the survey population; 78 patients returned a questionnaire for a response rate of 55.7%. Eighty percent of patients experienced driving as a regular part of life at some point prior to surgery. At the time of the questionnaire distribution, 68% of patients had returned to regular driving. Demographic characteristics did not play a significant role in whether or not the patient had a favorable driving outcome after surgery. However, patients who had a history of driving on a regular basis prior to surgery and those who had an Engel Class I outcome after surgery had significantly higher rates of good driving outcomes. Also, patients with an unfavorable preoperative driving status were more likely to have a favorable driving outcome after surgery if they had an Engel Class I outcome. Patients in whom intracranial electroencephalography (EEG) was utilized prior to resection had worse driving outcomes. CONCLUSIONS: A surprisingly high percentage of patients with epilepsy have experienced driving on a regular basis prior to surgery. We can assume that most patients were not driving immediately prior to surgery, given the fact that they had progressed to requiring surgery for treatment of their epilepsy. Thus, a driving rate of 68% after surgery can be considered good. We found that a patient's preoperative driving history, the use of intracranial EEG before surgical resection, and Engel classification were significant predictors of postoperative driving outcomes. These data provide patients with assistance in preoperative counseling. More investigation needs to be completed in other patient variables - such as seizure types, magnetic resonance imaging (MRI) findings, and patient motivators for driving - as possible predictors of driving outcomes.

A Multicenter Allelic Analysis of Diffuse Idiopathic Skeletal Hyperostosis: Nature Versus Nurture?

BACKGROUND: Diffuse idiopathic skeletal hyperostosis (DISH) is an incompletely defined disease process with no known unifying pathophysiological mechanism. OBJECTIVE: To our knowledge, no genetic studies have been performed in a North American population. To summarize genetic findings from previous studies and to comprehensively test for these associations in a novel and diverse, multi-institutional population. METHODS: Cross-sectional, single nucleotide polymorphism (SNP) analysis was performed in 55 of 121 enrolled patients with DISH. Baseline demographic data were available on 100 patients. Based on allele selection from previous studies and related disease conditions, sequencing was performed on COL11A2, COL6A6, fibroblast growth factor 2 gene, LEMD3, TGFB1, and TLR1 genes and compared with global haplotype rates. RESULTS: Consistent with previous studies, older age (mean 71 years), male sex predominance (80%), a high frequency of type 2 diabetes (54%), and renal disease (17%) were observed. Unique findings included high rates of tobacco use (11% currently smoking, 55% former smoker), a higher predominance of cervical DISH (70%) relative to other locations (30%), and an especially high rate of type 2 diabetes in patients with DISH and ossification of the posterior longitudinal ligament (100%) relative to DISH alone (100% vs 47%, P < .001). Compared with global allele rates, we found higher rates of SNPs in 5 of 9 tested genes ( P < .05). CONCLUSION: We identified 5 SNPs in patients with DISH that occurred more frequently than a global reference. We also identified novel environmental associations. We hypothesize that DISH represents a heterogeneous condition with both multiple genetic and environmental influences.

Review of Cerebrospinal Fluid Physiology and Dynamics: A Call for Medical Education Reform.

BACKGROUND: The flow of cerebrospinal fluid (CSF) has been described as a unidirectional system with the choroid plexus serving as the primary secretor of CSF and the arachnoid granulations as primary reabsorption site. This theory of neurosurgical forefathers has been universally adopted and taught as dogma. Many neuroscientists have found difficulty reconciling this theory with common pathologies, and recent studies have found that this "classic" hypothesis may not represent the full picture. OBJECTIVE: To review modern CSF dynamic theories and to call for medical education reform. METHODS: We reviewed the literature from January 1990 to December 2020. We searched the PubMed database using key terms "cerebrospinal fluid circulation," "cerebrospinal fluid dynamics," "cerebrospinal fluid physiology," "glymphatic system," and "glymphatic pathway." We selected articles with a primary aim to discuss either CSF dynamics and/or the glymphatic system. RESULTS: The Bulat-Klarica-Oreskovic hypothesis purports that CSF is secreted and reabsorbed throughout the craniospinal axis. CSF demonstrates similar physiology to that of water elsewhere in the body. CSF "circulates" throughout the subarachnoid space in a pulsatile to-and-fro fashion. Osmolarity plays a critical role in CSF dynamics. Aquaporin-4 and the glymphatic system contribute to CSF volume and flow by establishing osmolarity gradients and facilitating CSF movement. Multiple studies demonstrate that the choroid plexus does not play any significant role in CSF circulation. CONCLUSION: We have highlighted major studies to illustrate modern principles of CSF dynamics. Despite these, the medical education system has been slow to reform curricula and update learning resources.

Chasing the Cup: A Comprehensive Review of Spinal Cord Injuries in Hockey.

Ice hockey is a high-speed sport with a high rate of associated injury, including spinal cord injury (SCI). The incidence of hockey-related SCI has increased significantly in more recent years. A comprehensive literature search was conducted with the PubMed, Medline, Google Scholar, and Web of Science databases using the phrases "hockey AND spinal cord injuries" to identify relevant studies pertaining to hockey-related SCIs, equipment use, anatomy, and biomechanics of SCI, injury recognition, and return-to-play guidelines. Fifty-three abstracts and full texts were reviewed and included, ranging from 1983 to 2021. The proportion of catastrophic SCIs is high when compared to other sports. SCIs in hockey occur most commonly from a collision with the boards due to intentional contact resulting in axial compression, as well as flexion-related teardrop fractures that lead to spinal canal compromise and neurologic injury. Public awareness programs, improvements in equipment, and rule changes can all serve to minimize the risk of SCI. Hockey has a relatively high rate of associated SCIs occurring most commonly due to flexion-distraction injuries from intentional contact. Further investigation into equipment and hockey arena characteristics as well as future research into injury recognition and removal from and return to play is necessary.

Hannover Classification of Vestibular Schwannomas: A Reliability Study.

BACKGROUND: The Hannover classification of vestibular schwannomas is designed to stratify tumors based on extrameatal extension and compression of the brainstem. We have previously reported the reliability of the Koos system, but to date, no study has assessed the reliability of the similar Hannover classification. OBJECTIVE: We present an assessment of the intrarater and interrater reliability of the Hannover classification system. METHODS: After institutional review board approval was obtained, a cross-sectional group of the magnetic resonance imaging of 40 patients with vestibular schwannomas varying in size comprised the study sample. Four raters were selected to assign a Hannover grade to 50 total scans. Interrater and intrarater reliability was calculated and reported using Fleiss's kappa, Kendall's W, and intraclass correlation coefficient (ICC). RESULTS: Interrater observer reliability was found to be moderate when measured using Fleiss' kappa (0.49), extremely strong using Kendall's W (0.93), and excellent as calculated by ICC (0.88). The results were all statistically significant (P < 0.05). Intrarater reliability for Hannover grade ranged from 0.77 to 1.00 (substantial to perfect). By Kendall's W and ICC, all raters had near perfect or excellent agreement. The results were all statistically significant (P < 0.05). CONCLUSIONS: The Hannover classification is a reliable system for grading the size of vestibular schwannomas. This supports its continued use and previously published results of the literature in studies relying on this classification. Further studies are needed to evaluate its validity and determine its role in preoperative counseling and determining microsurgery and radiosurgery outcomes.

Hydroxyapatite ceramics in multilevel cervical interbody fusion - is there a role?

The aim of this study is to evaluate the efficacy of hydroxyapatite grafts in multilevel cervical interbody fusion during the one year follow-up. A total of 86 patients with degenerative cervical disc disease underwent all together 224 cervical interbody fusion procedures in which either Smith-Robinson or Cloward type hydroxyapatite grafts were used. The surgeries included radiculopathy in 38 cases, myelopathy in 20 cases and myeloradicuopathy in 28 patients. In 65 out of 86 patients, fusion was followed by an anterior instrumentation (plating). Postoperatively, patients were followed for a mean of 15.64 (range 11-23.3) months. All patients underwent radiography to evaluate fusion and the axis curvature. Excellent clinical results (86%), described as a complete or partial relief of symptoms with full return to preop activity, were obtained in patients with radiculopathy. There were 5 grafts mobilizations and one graft fracture. Two grafts extruded in non-instrumented patients and required repeated surgery. There were other three reoperations due to the hardware problems. One year fusion rate was obtained at 86% for two-level surgery, 80.1% for three-level surgery and 74% for four-level surgery. The mean (SD) hospital stay was 3.8 (0.7) days. A hydroxyapatite cheramic can be a very effective synthetic material for multilevel cervical interbody fusion. It is characterized by a high fusion rate and a small percentage of graft-related complications, especially when fusion procedure is followed by plating.

The Validity of the Koos Classification System With Respect to Facial Nerve Function.

BACKGROUND: The Koos classification of vestibular schwannomas is designed to stratify tumors based on extrameatal extension and compression of the brainstem. Our prior study demonstrated excellent reliability. No study has yet assessed its validity. OBJECTIVE: To present a retrospective study designed to assess the validity of the Koos grading system with respect to facial nerve function following treatment of 81 acoustic schwannomas. METHODS: We collected data retrospectively from 81 patients with acoustic schwannomas of various Koos grades who were treated with microsurgical resection or stereotactic radiosurgery. House-Brackmann (HB) scores were used to assess facial nerve function and obtained at various time points following treatment. We generated Spearman's rho and Kendall's tau correlation coefficients along with a logistic regression curve. RESULTS: We found no significant difference in the presence or absence of facial dysfunction by Koos classification when looking at all patients. There was a positive but fairly weak correlation between HB score and Koos classification, which was only significant at the first postoperative clinic appointment. There was a statistically significant difference in the presence or absence of facial dysfunction between patients treated with surgery vs radiation, which we expected. We found no statistically significant difference when comparing surgical approaches. Logistic regression modeling demonstrated a poor ability of the Koos grading system to predict facial nerve dysfunction following treatment. CONCLUSION: The Koos grading system did not predict the presence of absence of facial nerve dysfunction in our study population. There were trends within subgroups that require further exploration.

A Bibliometric Analysis of Neurosurgical Practice Guidelines.

BACKGROUND: In the last 20 yr, the rate of neurosurgical guideline publication has increased. However, despite the higher volume and increasing emphasis on quality there remains no reliable means of measuring the overall impact of clinical practice guidelines (CPGs). OBJECTIVE: To utilize citation analysis to evaluate the dispersion of neurosurgical CPGs. METHODS: A list of neurosurgical guidelines was compiled by performing electronic searches using the Scopus (Elsevier, Amsterdam, Netherlands) and National Guideline Clearinghouse databases. The Scopus database was queried to obtain current publication and citation data for all included documents and categorized based upon recognized neurosurgical specialties. The h-index, R-index, h2-index, i10-index, and dissemination index (D-Index) were manually calculated for each subspecialty. RESULTS: After applying screening criteria the search yielded 372 neurosurgical CPGs, which were included for bibliometric analysis. The overall calculated h-index for neurosurgery was 56. When broken down by subspecialty trauma/critical care had the highest value at 35, followed by spine and peripheral nerve at 30, cerebrovascular at 28, tumor at 16, pediatrics at 14, miscellaneous at 11, and functional/stereotactic/pain at 6. Cerebrovascular neurosurgery was noted to have the highest D-Index at 3.4. CONCLUSION: A comprehensive framework is useful for guideline impact analysis. Bibliometric data provides a novel and adequate means of evaluating the successful dissemination of neurosurgical guidelines. There remains a paucity of data regarding implementation and clinical outcomes of individual guidelines.

Developing Physician Leadership in Hospital Policy Development: A Case Study of Resident-Driven Policy Initiatives in the Department of Neurosurgery at the University of Alabama at Birmingham.

The bulk of a resident's daily work is patient care related; however, other aspects of residency training are vital both to a resident's education and to the advancement of the field. Basic science and clinical research are the more common academic activities in which residents participate after completion of daily patient care objectives. Less frequently, residents participate in a process vital to the delivery of efficient, cost-effective, and safe patient care: hospital policy development. Two policies were identified as outdated or absent: (1) the process for the declaration of brain death and (2) a policy for the use of hypertonic saline in the Neurosciences Intensive Care Unit. The policies were rewritten after review of the existing policy (when applicable), other institutions' examples, national guidelines, and state and federal laws. Once written, proposals were reviewed by department leadership, hospital ethics, legal counsel, ad hoc specialty committees, the Medical Directors Council, and the Medical Executive Committee. After multiple revisions, each proposal was endorsed by the above bodies and ratified as hospital policy. Residents may make a substantial impact on patient care through active participation in the authorship and implementation of hospital policy. The inclusion of residents in policy development has improved the process for declaring brain death and management of patients with devastating neurological pathology. Resident involvement in hospital policy initiatives can be successful, valuable to the institution, and beneficial to patient care. Resident involvement is predicated on faculty and institutional support of such endeavors.

Reserved Bed Program Reduces Neurosciences Intensive Care Unit Capacity Strain: An Implementation Study.

BACKGROUND: Neurosciences intensive care units (NICUs) provide institutional centers for specialized care. Despite a demonstrable reduction in morbidity and mortality, NICUs may experience significant capacity strain with resulting supraoptimal utilization and diseconomies of scale. We present an implementation study in the recognition and management of capacity strain within a large NICU in the United States. Excessive resource demand in an NICU creates significant operational issues. OBJECTIVE: To evaluate the efficacy of a Reserved Bed Pilot Program (RBPP), implemented to maximize economies of scale, to reduce transfer declines due to lack of capacity, and to increase transfer volume for the neurosciences service-line. METHODS: Key performance indicators (KPIs) were created to evaluate RBPP efficacy with respect to primary (strategic) objectives. Operational KPIs were established to evaluate changes in operational throughput for the neurosciences and other service-lines. For each KPI, pilot-period data were compared to the previous fiscal year. RESULTS: RBPP implementation resulted in a significant increase in accepted transfer volume to the neurosciences service-line (P = .02). Transfer declines due to capacity decreased significantly (P = .01). Unit utilization significantly improved across service-line units relative to theoretical optima (P < .03). Care regionalization was achieved through a significant reduction in "off-service" patient placement (P = .01). Negative externalities were minimized, with no significant negative impact in the operational KPIs of other evaluated service-lines (P = .11). CONCLUSION: Capacity strain is a significant issue for hospital units. Reducing capacity strain can increase unit efficiency, improve resource utilization, and augment service-line throughput. RBPP implementation resulted in a significant improvement in service-line operations, regional access to care, and resource efficiency, with minimal externalities at the institutional level.

Diagnosis of Ventricular Shunt Infection in Children: A Systematic Review.

BACKGROUND: No widely accepted gold standard for diagnosis of shunt infection exists, with definitions variable among clinicians and publications. This article summarizes the utility of commonly used diagnostic tools and provides a comprehensive review of optimal measures for diagnosis. METHODS: A query of PubMed was performed extracting articles related to shunt infection in children. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed, resulting in 1756 articles related to shunt infection, 49 of which ultimately met inclusion criteria. RESULTS: Of the 49 articles included in the analysis, 9 did not define infection, 9 used culture alone, 9 used cultures and/or symptomatology, and 4 used a combination of cultures, cerebral spinal fluid (CSF) pleocytosis and symptomatology. The remainder of the studies used definitions from the Centers for Disease Control and Prevention (n = 2) and the Hydrocephalus Clinical Research Network (n = 2) or borrowed elements from these definitions. Variation in definition stems from the lack of sensitivity and specificity of commonly used signs, symptoms, and tests. Shunt tap alone is considered half as sensitive as hardware culture. Fever upon presentation was present in 16% to 42% of cases. CSF pleocytosis combined with fever has a sensitivity of 82% and specificity of 99%. CSF eosinophilia, lactic acid, serum anti-Staphylococcus epidermidis titer, procalcitonin, and C-reactive protein are non-specific and their utility is not well established. CONCLUSIONS: The definition of shunt infection is variable across studies, with CSF culture and/or symptomatology being the most commonly utilized parameters.

The case for the future role of evidence-based medicine in the management of cervical spine injuries, with or without fractures.

The authors believe that the standardized and systematic study of immobilization techniques, diagnostic modalities, medical and surgical treatment strategies, and ultimately outcomes and outcome measurement after cervical spinal trauma and cervical spinal fracture injuries, if performed using well-designed medical evidence-based comparative investigations with meaningful follow-up, has both merit and the remarkable potential to identify optimal strategies for assessment, characterization, and clinical management. However, they recognize that there is inherent difficulty in attempting to apply evidence-based medicine (EBM) to identify ideal treatment strategies for individual cervical fracture injuries. First, there is almost no medical evidence reported in the literature for the management of specific isolated cervical fracture subtypes; specific treatment strategies for specific fracture injuries have not been routinely studied in a rigorous, comparative way. One of the vulnerabilities of an evidenced-based scientific review in spinal cord injury (SCI) is the lack of studies in comparative populations and scientific evidence on a given topic or fracture pattern providing level II evidence or higher. Second, many modest fracture injuries are not associated with vascular or neural injury or spinal instability. The application of the science of EBM to the care of patients with traumatic cervical spine injuries and SCIs is invaluable and necessary. The dedicated multispecialty author groups involved in the production and publication of the two iterations of evidence-based guidelines on the management of acute cervical spine and spinal cord injuries have provided strategic guidance in the care of patients with SCIs. This dedicated service to the specialty has been carried out to provide neurosurgical colleagues with a qualitative review of the evidence supporting various aspects of care of these patients. It is important to state and essential to understand that the science of EBM and its rigorous application is important to medicine and to the specialty of neurosurgery. It should be embraced and used to drive and shape investigations of the management and treatment strategies offered patients. It should not be abandoned because it is not convenient or it does not support popular practice bias or patterns. It is the authors' view that the science of EBM is essential and necessary and, furthermore, that it has great potential as clinician scientists treat and study the many variations and complexities of patients who sustain acute cervical spine fracture injuries.

The Impact of Different Postgraduate Year Training in Neurosurgery Residency on 30-Day Postoperative Outcomes.

BACKGROUND: Previous studies have failed to demonstrate statistically significant differences in postsurgical outcomes between operative cases featuring resident participation compared to attending only; however, the effects of level of postgraduate year (PGY) training have not been explored. OBJECTIVE: To correlate different PGYs in neurosurgery with 30-d postoperative outcomes. METHODS: Using National Surgical Quality Improvement Program 2005-2014, adult neurosurgical cases were divided into subspecialties: spine, open-vascular, cranial, and functional in teaching institutions. Comparison groups: cases involving junior residents (PGY 1-PGY 3), mid-level residents (PGY 4 + PGY 5), and senior residents (PGY 6 + PGY 7). Primary outcome measures included any wound disruption (surgical site infections and/or wound dehiscence), Clavien-Dindo grade IV (life-threatening) complications, and death. RESULTS: Compared to junior residents (n = 3729) and mid-level residents (n = 2779), senior residents (n = 3692) operated on patients with a greater comorbidity burden, as reflected by higher American Society of Anesthesiology classifications and decreased level of functional status. Cases with senior resident participation experienced the highest percentages of postoperative wound complications (P = .005), Clavien-Dindo grade IV complications (P = .001), and death (P = .035). However, following multivariable regression, level of residency training in neurosurgery did not predict any of the 3 primary outcome measures. Compared to spinal cases, cranial cases predicted a higher incidence of life-threatening complications (odds ratio 1.84, P < .001). CONCLUSION: Cases in the senior resident cohort were more technically challenging and exhibited a higher comorbidity burden preoperatively; however, level of neurosurgical training did not predict any wound disruption, life-threatening complications, or death. Residents still provide safe and effective assistance to attending neurosurgeons.

Towards Evidence-Based Guidelines in Neurological Surgery.

Neurological surgery practice is based on the science of balancing probabilities. A variety of clinical guidance documents have influenced how we collectively practice our art since the early 20th century. The quality of the science within these guidelines varies widely, as does their utility in positively shaping our practice. The guidelines development process in neurological surgery has evolved significantly over the last 30 yr. Historically based in expert opinion, as a specialty we have increasingly relied on objective medical evidence to guide our clinical practice. We assessed the changing practice guidelines development process and the impact of scientifically robust guidelines on patient care. The evolution of the guidelines development process in neurological surgery was chronicled. Several subspecialty guidelines were extracted and reviewed in detail. Their impact on practice patterns was evaluated. The importance of evidence-based research and practice guidelines development was discussed. Evidence-based practice guidelines serve to chronicle multiple acceptable treatment options and help us move towards more standardized care for specific disease processes. They help refute false "standards of care." Guidelines-based care supported by solid medical evidence has the potential to streamline patient care and improve patient outcomes. The guidelines development process identifies areas, issues, and strategies for which little medical evidence exists, as well as topics that need focused scientific investigation and future study. The production of evidence-based practice recommendations is a vital part of furthering our specialty. Guidelines development advances our science, augments the resident education process, and protects our practice from undue external influence.

What is a Case-Control Study?

Case-control (case-control, case-controlled) studies are beginning to appear more frequently in the neurosurgical literature. They can be more robust, if well designed, than the typical case series or even cohort study to determine or refine treatment algorithms. The purpose of this review is to define and explore the differences between case-control studies and other so-called nonexperimental, quasiexperimental, or observational studies in determining preferred treatments for neurosurgical patients.

What Isn't a Case-Control Study?

BACKGROUND: Confusion exists among neurosurgeons when choosing and implementing an appropriate study design and statistical methods when conducting research. We noticed particular difficulty with mislabeled and inappropriate case-control studies in the neurosurgical literature. OBJECTIVE: To quantify and to rigorously review this issue for appropriateness in publication and to establish quality of the manuscripts using a rigorous technique. METHODS: Following a literature search, pairs drawn from 5 independent reviewers evaluated a complete sample of 125 manuscripts claiming to be case-control studies with respect to basic case-control criteria. Seventy-five papers were then subjected to a more rigorous appraisal for quality using the SIGN Methodology Checklist for case-control studies. RESULTS: Fifty publications were rejected based on basic criteria used to identify case-control design. Of the 75 subjected to quality analysis, 46 were felt to be acceptable for publication. Only 11 papers (9%) achieved the designation of high quality. Of the original 125 papers evaluated, 79 (63%) were inappropriately labeled case-control studies. CONCLUSION: Mislabeling and use of inappropriate study design are common in the neurosurgical literature. Manuscripts should be evaluated rigorously by reviewers and readers, and neurosurgical training programs should include instruction on choice of appropriate study design and critical appraisal of the literature.

Koos Classification of Vestibular Schwannomas: A Reliability Study.

BACKGROUND: The Koos classification of vestibular schwannomas is designed to stratify tumors based on extrameatal extension and compression of the brainstem. While this classification system is widely reported in the literature, to date no study has assessed its reliability. OBJECTIVE: To assess the intra- and inter-rater reliability of the Koos classification system. METHODS: After institutional review board approval was obtained, a cross-sectional group of the Magnetic Resonance imagings of 40 patients with vestibular schwannomas varying in size comprised the study sample. Four raters were selected to assign a Koos grade to 50 total scans. Inter- and intrarater reliability were calculated and reported using Fleiss' kappa, Kendall's W, and Intraclass correlation coefficient (ICC). RESULTS: Inter-rater reliability was found to be substantial when measured using Fleiss' kappa (.71), extremely strong using Kendall's W (.92), and excellent as calculated by ICC (.88).Intrarater reliability was perfect for 3 out of 4 raters as assessed using weighted kappa, Kendall's W and ICC, with the intrarater agreement for the fourth rater measured as extremely high. CONCLUSION: We have demonstrated that the Koos classification system for vestibular schwannoma is a reliable method for tumor classification. This study lends further support to the results of current literature using Koos grading system. Further studies are required to evaluate its validity and utility in counseling patients with regard to outcomes.