The 50 most-cited articles in Neurosurgery, 2017

BACKGROUND: Traumatic spinal cord injuries (SCI) have devastating consequences for the physical, financial, and psychosocial well-being of patients and their caregivers. Expediently delivering interventions during the early postinjury period can have a tremendous impact on long-term functional recovery. PATHOPHYSIOLOGY: This is largely due to the unique pathophysiology of SCI where the initial traumatic insult (primary injury) is followed by a progressive secondary injury cascade characterized by ischemia, proapoptotic signaling, and peripheral inflammatory cell infiltration. Over the subsequent hours, release of proinflammatory cytokines and cytotoxic debris (DNA, ATP, reactive oxygen species) cyclically adds to the harsh postinjury microenvironment. As the lesions mature into the chronic phase, regeneration is severely impeded by the development of an astroglial-fibrous scar surrounding coalesced cystic cavities. Addressing these challenges forms the basis of current and upcoming treatments for SCI. MANAGEMENT: This paper discusses the evidence-based management of a patient with…

BACKGROUND: Despite many publications about cerebral cavernous malformations (CCMs), controversy remains regarding diagnostic and management strategies. OBJECTIVE: To develop guidelines for CCM management. METHODS: The Angioma Alliance ( www.angioma.org ), the patient support group in the United States advocating on behalf of patients and research in CCM, convened a multidisciplinary writing group comprising expert CCM clinicians to help summarize the existing literature related to the clinical care of CCM, focusing on 5 topics: (1) epidemiology and natural history, (2) genetic testing and counseling, (3) diagnostic criteria and radiology standards, (4) neurosurgical considerations, and (5) neurological considerations. The group reviewed literature, rated evidence, developed recommendations, and established consensus, controversies, and knowledge gaps according to a prespecified protocol. RESULTS: Of 1270 publications published between January 1, 1983 and September 31, 2014, we selected 98 based on methodological criteria, and identified 38 additional recent or relevant…

Intervertebral disk (IVD) degeneration is a natural progression of the aging process. Degenerative disk disease (DDD) is a pathologic condition associated with IVD that has been associated with chronic back pain. There are a variety of different mechanisms of DDD (genetic, mechanical, exposure). Each of these pathways leads to a final common result of unbalancing the anabolic and catabolic environment of the extracellular matrix in favor of catabolism. Attempts have been made to gain an understanding of the process of IVD degeneration with in Vitro studies. These models help our understanding of the disease process, but are limited as they do not come close to replicating the complexities that exist with an in Vivo model. Animal models have been developed to help us gain further understanding of the degenerative cascade of IVD degeneration In Vivo and test experimental treatment modalities to either prevent or reverse the process of DDD. Many modalities for treatment of DDD have been developed including therapeutic protein injections, stem cell injections, gene therapy, and tissue…

Neuroimaging plays an ever evolving role in the diagnosis, treatment planning, and post-therapy assessment of brain tumors. This review provides an overview of current magnetic resonance imaging (MRI) methods routinely employed in the care of the brain tumor patient. Specifically, we focus on advanced techniques including diffusion, perfusion, spectroscopy, tractography, and functional MRI as they pertain to noninvasive characterization of brain tumors and pretreatment evaluation. The utility of both structural and physiological MRI in the post-therapeutic brain evaluation is also reviewed with special attention to the challenges presented by pseudoprogression and pseudoresponse.

Spine surgery has experienced much technological innovation over the past several decades. The field has seen advancements in operative techniques, implants and biologics, and equipment such as computer-assisted navigation and surgical robotics. With the arrival of real-time image guidance and navigation capabilities along with the computing ability to process and reconstruct these data into an interactive three-dimensional spinal "map", so too have the applications of surgical robotic technology. While spinal robotics and navigation represent promising potential for improving modern spinal surgery, it remains paramount to demonstrate its superiority as compared to traditional techniques prior to assimilation of its use amongst surgeons.The applications for intraoperative navigation and image-guided robotics have expanded to surgical resection of spinal column and intradural tumors, revision procedures on arthrodesed spines, and deformity cases with distorted anatomy. Additionally, these platforms may mitigate much of the harmful radiation exposure in minimally invasive surgery to…

BACKGROUND: Machine learning (ML) is a domain of artificial intelligence that allows computer algorithms to learn from experience without being explicitly programmed. OBJECTIVE: To summarize neurosurgical applications of ML where it has been compared to clinical expertise, here referred to as "natural intelligence." METHODS: A systematic search was performed in the PubMed and Embase databases as of August 2016 to review all studies comparing the performance of various ML approaches with that of clinical experts in neurosurgical literature. RESULTS: Twenty-three studies were identified that used ML algorithms for diagnosis, presurgical planning, or outcome prediction in neurosurgical patients. Compared to clinical experts, ML models demonstrated a median absolute improvement in accuracy and area under the receiver operating curve of 13% (interquartile range 4-21%) and 0.14 (interquartile range 0.07-0.21), respectively. In 29 (58%) of the 50 outcome measures for which a P-value was provided or calculated, ML models outperformed clinical experts (P < .05). In 18 of 50 (36%), no…

BACKGROUND: Spine surgery is complicated by an incidence of 1% to 9% of surgical site infection (SSI). The most common organisms are gram-positive bacteria and are endogenous, that is are brought to the hospital by the patient. Efforts to improve safety have been focused on reducing SSI using a bundle approach. The bundle approach applies many quality improvement efforts and has been shown to reduce SSI in other surgical procedures. OBJECTIVE: To provide a narrative review of practical solutions to reduce SSI in spine surgery. METHODS: Literature review and synthesis to identify methods that can be used to prevent SSI. RESULTS: SSI prevention starts with proper patient selection and optimization of medical conditions, particularly reducing smoking and glycemic control. Screening for staphylococcus organisms and subsequent decolonization is a promising method to reduce endogenous bacterial burden. Preoperative warming of patients and timely administration of antibiotics are critical to prevent SSI. Skin preparation using chlorhexidine and alcohol solutions are recommended. Meticulous…

BACKGROUND: Early brain injury (EBI) after subarachnoid hemorrhage (SAH) is an important determinant of clinical outcomes. However, a major hindrance to studies of EBI is the lack of radiographic surrogate marker. OBJECTIVE: To propose a scoring system based on early changes in clinically obtained computed tomography (CT), called the Subarachnoid hemorrhage Early Brain Edema Score (SEBES). METHODS: Patients with spontaneous aneurysmal SAH and a CT within 24 h of ictus were included. We defined SEBES as a scale of 0 to 4 points according to the (1) absence of visible sulci caused by effacement of sulci or (2) absence of visible sulci with disruption of the gray-white matter junction at 2 predetermined levels in each hemisphere. Prognostic value of the SEBES grade for the prediction of delayed cerebral ischemia (DCI) and unfavorable outcomes was assessed. A separate cohort of patients was used as a validation cohort. RESULTS: Of the 164 subjects in our study, high-grade SEBES (3 or 4 points) was identified in 48 patients (29.3%). CT interobserver reliability of SEBES grades was high…

Treatment paradigms for patients with spine metastases have evolved significantly over the past decade. Incorporating stereotactic radiosurgery into these paradigms has been particularly transformative, offering precise delivery of tumoricidal radiation doses with sparing of adjacent tissues. Evidence supports the safety and efficacy of radiosurgery as it currently offers durable local tumor control with low complication rates even for tumors previously considered radioresistant to conventional radiation. The role for surgical intervention remains consistent, but a trend has been observed toward less aggressive, often minimally invasive, techniques. Using modern technologies and improved instrumentation, surgical outcomes continue to improve with reduced morbidity. Additionally, targeted agents such as biologics and checkpoint inhibitors have revolutionized cancer care, improving both local control and patient survivals. These advances have brought forth a need for new prognostication tools and a more critical review of long-term outcomes. The complex nature of current treatment…

BACKGROUND: Cranioplasty after decompressive craniectomy is a common neurosurgical procedure, yet the optimal timing of cranioplasty has not been well established. OBJECTIVE: To investigate whether the timing of cranioplasty is associated with differences in neurological outcome. METHODS: A systematic literature review and meta-analysis was performed using MEDLINE, Scopus, and the Cochrane databases for studies reporting timing and neurological assessment for cranioplasty after decompressive craniectomy. Pre- and postcranioplasty neurological assessments for cranioplasty performed within (early) and beyond (late) 90 d were extracted. The standard mean difference (SMD) was used to normalize all neurological measures. Available data were pooled to compare pre-cranioplasty, postcranioplasty, and change in neurological status between early and late cranioplasty cohorts, and in the overall population. RESULTS: Eight retrospective observational studies were included for a total of 528 patients. Studies reported various outcome measures (eg, Barthel Index, Karnofsky Performance Scale,…

BACKGROUND: Due to uncertain evidence, lumbar fusion for degenerative indications is associated with the greatest measured practice variation of any surgical procedure. OBJECTIVE: To summarize the current evidence on the comparative safety and efficacy of lumbar fusion, decompression-alone, or nonoperative care for degenerative indications. METHODS: A systematic review was conducted using PubMed, MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials (up to June 30, 2016). Comparative studies reporting validated measures of safety or efficacy were included. Treatment effects were calculated through DerSimonian and Laird random effects models. RESULTS: The literature search yielded 65 studies (19 randomized controlled trials, 16 prospective cohort studies, 15 retrospective cohort studies, and 15 registries) enrolling a total of 302 620 patients. Disability, pain, and patient satisfaction following fusion, decompression-alone, or nonoperative care were dependent on surgical indications and study methodology. Relative to decompression-alone, the risk of reoperation…

BACKGROUND: A craniotomy with direct cortical/subcortical stimulation either awake or under general anesthesia (GA) present 2 approaches for removing eloquent region tumors. With a reported higher prevalence of intraoperative seizures occurring during awake resections of perirolandic lesions, oftentimes, surgery under GA is chosen for these lesions. OBJECTIVE: To evaluate a single-surgeon's experience with awake craniotomies (AC) vs surgery under GA for resecting perirolandic, eloquent, motor-region gliomas. METHODS: Between 2005 and 2015, a retrospective analysis of 27 patients with perirolandic, eloquent, motor-area gliomas that underwent an AC were case-control matched with 31 patients who underwent surgery under GA for gliomas in the same location. All patients underwent direct brain stimulation with neuromonitoring and perioperative risk factors, extent of resection, complications, and discharge status were assessed. RESULTS: The postoperative Karnofsky Performance Score (KPS) was significantly lower for the GA patients at 81.1 compared to the AC patients at 93.3 ( P = .040).…

BACKGROUND: Vertebral compression fracture (VCF) is a challenging and not infrequent complication observed following spine stereotactic body radiation therapy (SBRT). OBJECTIVE: To summarize the data from the multiple studies that have been published, addressing the risk and predictive factors for VCF post-SBRT. METHODS: A systematic literature review was conducted. Studies were selected if they specifically addressed risk factors for post-SBRT VCF in their analyses. RESULTS: A total of 11 studies were identified, reporting both the risk of VCF post-SBRT and an analysis of risk factors based on univariate and multivariate analysis. A total of 2911 spinal segments were treated with a crude VCF rate of 13.9%. The most frequently identified risk factors on multivariate analysis were: lytic disease (hazard ratio [HR] range, 2.76-12.2), baseline VCF prior to SBRT (HR range, 1.69-9.25), higher dose per fraction SBRT (HR range, 5.03-6.82), spinal deformity (HR range, 2.99-11.1), older age (HR range, 2.15-5.67), and more than 40% to 50% of vertebral body involved by tumor (HR range,…

BACKGROUND: Human central nervous system stem cells (HuCNS-SC) are multipotent adult stem cells with successful engraftment, migration, and region-appropriate differentiation after spinal cord injury (SCI). OBJECTIVE: To present data on the surgical safety profile and feasibility of multiple intramedullary perilesional injections of HuCNS-SC after SCI. METHODS: Intramedullary free-hand (manual) transplantation of HuCNS-SC cells was performed in subjects with thoracic (n = 12) and cervical (n = 17) complete and sensory incomplete chronic traumatic SCI. RESULTS: Intramedullary stem cell transplantation needle times in the thoracic cohort (20 M HuCNS-SC) were 19:30 min and total injection time was 42:15 min. The cervical cohort I (n = 6), demonstrated that escalating doses of HuCNS-SC up to 40 M range were well tolerated. In cohort II (40 M, n = 11), the intramedullary stem cell transplantation needle times and total injection time was 26:05 ± 1:08 and 58:14 ± 4:06 min, respectively. In the first year after injection, there were 4 serious adverse events in 4 of the 12 thoracic subjects…

BACKGROUND: Intracranial aneurysm rupture prediction is poor, with only a few risk factors for rupture identified and used in clinical practice. OBJECTIVE: To provide an overview of all the risk factors (including genetic, molecular, morphological, and hemodynamic factors) that have potential for use in clinical practice. METHODS: We systematically searched PubMed and EMBASE and focused on factors that can be easily assessed in clinical practice, might be used for rupture prediction in clinical practice, and/or are potential targets for further research. Studies were categorized according to methodological quality, and a meta-analysis was performed, if possible. RESULTS: We included 102 studies describing 144 risk factors that fulfilled predefined criteria. There was strong evidence for the morphological factors irregular shape (studied in 4 prospective cohort studies of high-quality, pooled odds ratio [OR] of 4.8 [95% confidence interval 2.7-8.7]), aspect ratio (pooled OR 10.2 [4.3-24.6]), size ratio, bottleneck factor, and height-to-width ratio to increase rupture risk. Moderate…

Question 1: What is the overall probability of maintaining serviceable hearing following stereotactic radiosurgery utilizing modern dose planning, at 2, 5, and 10 yr following treatment? Recommendation: Level 3: Individuals who meet these criteria and are considering stereotactic radiosurgery should be counseled that there is moderately high probability (>50%-75%) of hearing preservation at 2 yr, moderately high probability (>50%-75%) of hearing preservation at 5 yr, and moderately low probability (>25%-50%) of hearing preservation at 10 yr. Question 2: Among patients with AAO-HNS (American Academy of Otolaryngology-Head and Neck Surgery hearing classification) class A or GR (Gardner-Robertson hearing classification) grade I hearing at baseline, what is the overall probability of maintaining serviceable hearing following stereotactic radiosurgery, utilizing modern dose planning, at 2, 5, and 10 yr following treatment? Recommendation: Level 3: Individuals who meet these criteria and are considering stereotactic radiosurgery should be counseled that there is a high probability…

BACKGROUND: There are conflicting data between natural history studies suggesting a very low risk of rupture for small, unruptured intracranial aneurysms and retrospective studies that have identified a much higher frequency of small, ruptured aneurysms than expected. OBJECTIVE: To use the prospective International Study of Unruptured Intracranial Aneurysms cohort to identify morphological characteristics predictive of unruptured intracranial aneurysm rupture. METHODS: A case-control design was used to analyze morphological characteristics associated with aneurysm rupture in the International Study of Unruptured Intracranial Aneurysms database. Fifty-seven patients with ruptured aneurysms during follow-up were matched (by size and location) with 198 patients with unruptured intracranial aneurysms without rupture during follow-up. Twelve morphological metrics were measured from cerebral angiograms in a blinded fashion. RESULTS: Perpendicular height (P = .008) and size ratio (ratio of maximum diameter to the parent vessel diameter; P = .01) were predictors of aneurysm rupture on…

BACKGROUND: There is no widely adopted grading system for the prediction of postoperative recurrence requiring reoperation (RrR) in patients with chronic subdural hematoma (CSDH). OBJECTIVE: We developed a CSDH grading system to predict RrR based on predictive characteristics that can be objectively assessed at the time of first presentation and initial surgery. METHODS: Prospectively collected data from 107 consecutive surgical patients with CSDH were reviewed. Predictors of RrR were identified via logistic and lasso regression analyses. A prognostic CSDH grading system was proposed, with the weighing of predictors based on strength of association. The scoring system was then applied to the same set of patients in our database for internal validation. RESULTS: The strongest predictors of RrR were an isodense or hyperdense lesions and laminar or separated lesions, and a postoperative CSDH cavity volume greater than 200 mL. The moderate predictors of RrR were a postoperative CSDH cavity volume of 80 to 200 mL and a preoperative CSDH volume greater than 130 mL. According to the…

RECOMMENDATIONS Diagnostic Level I Multimodality intraoperative monitoring (MIOM), including somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) recording, during spinal cord/spinal column surgery is a reliable and valid diagnostic adjunct to assess spinal cord integrity and is recommended if utilized for this purpose. MEP recordings are superior to SSEP recordings during spinal cord/spinal column surgery as diagnostic adjuncts for assessment of spinal cord integrity and are recommended if utilized for this purpose. Level II SSEP recordings during spinal cord/spinal column surgery are reliable and valid diagnostic adjuncts to describe spinal cord integrity and are recommended if utilized for this purpose. Therapeutic (Preventive) Level II MIOM, including SSEPs and MEP recording, during spinal cord/spinal column surgery does not improve gross total tumor resection or improve neurological outcome, when utilized during intramedullary tumor resection procedures (no therapeutic benefit). Level III There is insufficient evidence to suggest a therapeutic relationship…

BACKGROUND: Cranioplasty after decompressive craniectomy (DC) is routinely performed for reconstructive purposes and has been recently linked to improved cerebral blood flow (CBF) and neurological function. OBJECTIVE: To systematically review all available literature to evaluate the effect of cranioplasty on CBF and neurocognitive recovery. METHODS: A PubMed, Google Scholar, and MEDLINE search adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines included studies reporting patients who underwent DC and subsequent cranioplasty in whom cerebral hemodynamics were measured before and after cranioplasty. RESULTS: The search yielded 21 articles with a total of 205 patients (range 3-76 years) who underwent DC and subsequent cranioplasty. Two studies enrolled 29 control subjects for a total of 234 subjects. Studies used different imaging modalities, including CT perfusion (n = 10), Xenon-CT (n = 3), single-photon emission CT (n = 2), transcranial Doppler (n = 6), MR perfusion (n = 1), and positron emission tomography (n = 2). Precranioplasty CBF…

BACKGROUND: Over the last several decades, significant advances have occurred in the assessment and management of spinal deformity. OBJECTIVE: The primary focus of this narrative review is on recent advances in adult thoracic, thoracolumbar, and lumbar deformities, with additional discussions of advances in cervical deformity and pediatric deformity. METHODS: A review of recent literature was conducted. RESULTS: Advances in adult thoracic, thoracolumbar, and lumbar deformities reviewed include the growing applications of stereoradiography, development of new radiographic measures and improved understanding of radiographic alignment objectives, increasingly sophisticated tools for radiographic analysis, strategies to reduce the occurrence of common complications, and advances in minimally invasive techniques. In addition, discussion is provided on the rapidly advancing applications of predictive analytics and outcomes assessments that are intended to improve the ability to predict risk and outcomes. Advances in the rapidly evolving field of cervical deformity focus on better…

Background: Decompression without fusion is a treatment option in patients with lumbar spinal stenosis (LSS) associated with stable low-grade degenerative spondylolisthesis (DS). A minimally invasive unilateral laminotomy (MIL) for "over the top" decompression might be a less destabilizing alternative to traditional open laminectomy (OL). Objective: To review secondary fusion rates after open vs minimally invasive decompression surgery. Methods: We performed a literature search in Pubmed/MEDLINE using the keywords "lumbar spondylolisthesis" and "decompression surgery." All studies that separately reported the outcome of patients with LSS+DS that were treated by OL or MIL (transmuscular or subperiosteal route) were included in our systematic review and meta-analysis. The primary end point was secondary fusion rate. Secondary end points were total reoperation rate, postoperative progression of listhetic slip, and patient satisfaction. Results: We identified 37 studies (19 with OL, 18 with MIL), with a total of 1156 patients, that were published between 1983 and 2015. The studies'…

BACKGROUND: Enhancing Recovery After Surgery (ERAS®) programs have been widely adopted throughout the world, but not in spinal surgery. In this report, we review the implementation of a "fast track" surgery for lumbar fusion and its effect on acute care hospitalization costs. OBJECTIVE: To determine if a "fast track" surgery methodology results in acute care cost savings. METHODS: Thirty-eight consecutive ERAS patients were compared with patients undergoing conventional minimally invasive transforaminal lumbar interbody fusion. Differences between these groups included the use of endoscopic decompression, injections of liposomal bupivacaine, and performing the surgery under sedation in the ERAS® group. RESULTS: Patients had similar medical comorbidities (2.02 vs 2 for ERAS® and comparator groups, respectively; P = .458). Body mass index was similar (26.5 vs 27.0; P = .329). ERAS® patients were older (65 vs 59 yr, P = .031). Both groups had excellent clinical results with an improvement of 23% and 24%, respectively. Intraoperative blood loss was less (68 ± 31 cc vs 231 ± 73, P <…

BACKGROUND: Women represent a growing cohort of US neurosurgeons. OBJECTIVE: To describe postresidency fellowship, practice environment, and updated academic rank among female neurosurgeons. METHODS: Databases from the American Association of Neurological Surgeons (AANS) and the American Board of Neurological Surgery (ABNS) from 1964 to 2013 were reviewed for female neurosurgery residency graduates. Data on postresidency fellowships, practice environment (private vs academic), academic rank, board certification, and AANS/CNS (Congress of Neurological Surgeons) Joint Section on Women in Neurosurgery (WINS) membership were collected in 2016. Academic rank was verified from program websites and electronic correspondence. Faculty members were asked to report directorships and tenure. The AANS/CNS Joint Section on Women in Neurosurgery verified WINS membership. RESULTS: A total of 379 female neurosurgery residency graduates were identified in this 50-yr span. Of these, 70% became ABNS certified, and 2.1% left neurosurgery. Twenty-seven percent of women (n = 103) pursued fellowships, with…

BACKGROUND: A substantial body of evidence suggests that cytoreductive surgery is a prerequisite to prolonging survival in patients with glioblastoma (GBM). OBJECTIVE: To evaluate the safety and impact of "supratotal" resections beyond the zone of enhancement seen on magnetic resonance imaging scans, using a subpial technique. METHODS: We retrospectively evaluated 86 consecutive patients with primary GBM, managed by the senior author, using a subpial resection technique with or without carmustine (BCNU) wafer implantation. Multivariate Cox proportional hazards regression was used to analyze clinical, radiological, and outcome variables. Overall impacts of extent of resection (EOR) and BCNU wafer placement were compared using Kaplan-Meier survival analysis. RESULTS: Mean patient age was 56 years. The median OS for the group was 18.1 months. Median OS for patients undergoing gross total, near-total, and subtotal resection were 54, 16.5, and 13.2 months, respectively. Patients undergoing near-total resection ( P = .05) or gross total resection ( P < .01) experienced statistically…

BACKGROUND: Five-aminolevulinic acid (5-ALA) is used for fluorescence-guided resections of malignant glioma at a dose of 20 mg/kg; yet, it is unknown whether lower doses may also provide efficacy. OBJECTIVE: To perform a double-blinded randomized study comparing 3 different doses of 5-ALA. METHODS: Twenty-one patients with suspected malignant glioma were randomly assigned to 0.2, 2, or 20 mg/kg 5-ALA. Investigators were unaware of dose. Intraoperatively, regions of interest were first defined in tumor core, margin, and adjacent white matter under white light. Under violet-blue illumination, the surgeon's impression of fluorescence was recorded per region, followed by spectrometry and biopsy. Plasma was collected after administration and analyzed for 5-ALA and protoporphyrin IX (PPIX) content. RESULTS: The positive predictive value of fluorescence was 100%. Visual and spectrometric fluorescence assessment showed 20 mg/kg to elicit the strongest fluorescence in tumor core and margins, which correlated with cell density. Spectrometric and visual fluorescence correlated significantly. A…

Odontoid fractures are the most common fracture of the axis and the most common cervical spine fracture in patients over 65. Despite their frequency, there is considerable ambiguity regarding optimal management strategies for these fractures in the elderly. Poor bone health and medical comorbidities contribute to increased surgical risk in this population; however, nonoperative management is associated with a risk of nonunion or fibrous union. We provide a review of the existing literature and discuss the classification and evaluation of odontoid fractures. The merits of operative vs nonoperative management, fibrous union, and the choice of operative approach in elderly patients are discussed. A treatment algorithm is presented based on the available literature. We believe that type I and type III odontoid fractures can be managed in a collar in most cases. Type II fractures with any additonal risk factors for nonunion (displacement, comminution, etc) should be considered for surgical management. However, the risks of surgery in an elderly population must be carefully considered on…

Cervical spine deformities can have a significant negative impact on the quality of life by causing pain, myelopathy, radiculopathy, sensorimotor deficits, as well as inability to maintain horizontal gaze in severe cases. Many different surgical options exist for operative management of cervical spine deformities. However, selecting the correct approach that ensures the optimal clinical outcome can be challenging and is often controversial. We aim to provide an overview of cervical spine deformity in a 3-part series covering topics including the biomechanics, radiographic parameters, classification, treatment algorithms, surgical techniques, clinical outcome, and complication avoidance with a review of pertinent literature.

Painful terminal neuromas resulting from nerve injury following amputation are common. However, there is currently no universally accepted gold standard of treatment for this condition. A comprehensive literature review is presented on the treatment of terminal neuromas. Four categories of terminal neuroma surgical procedures are assessed: epineurial closure; nerve transposition with implantation; neurorrhaphy, and alternate target reinnervation. Significant patient and case studies are highlighted in each section, focusing on surgical technique and patient outcome metrics. Studies presented consisted of a PubMed search for "terminal neuromas," without year limitation. The current available research supports the use of implantation into muscle for the surgical treatment of terminal neuromas. However, this technique has several fundamental flaws that limit its utility, as it does not address the underlying physiology behind neuroma formation. Regenerative peripheral nerve interfaces and targeted muscle reinnervation are 2 techniques that seem to offer the most promise in preventing…

Degenerative cervical myelopathy (DCM) is a common cause of spinal cord dysfunction that confronts clinicians on a daily basis. Research performed over the past few decades has provided improved insight into the diagnosis, evaluation, and treatment of this disorder. We aim to provide clinicians with an update regarding the state of the art in DCM, focusing on more recent research pertaining to pathophysiology, natural history, treatment, consideration of the minimally symptomatic patient, surgical outcome prediction, and outcome measurement. Current concepts of pathophysiology focus on the combination of static and dynamic elements leading to breakdown of the blood-spinal cord barrier at the site of compression resulting in local inflammation, cellular dysfunction, and apoptosis. With respect to treatment, although there is a dearth of high-quality studies comparing surgical to nonoperative treatment, several large prospective studies have recently associated surgical management with clinically and statistically significant improvement in functional, disability, and quality of life…

BACKGROUND: Risk factors for pre- and postoperative seizures in supratentorial meningiomas are understudied compared to other brain tumors. OBJECTIVE: To report seizure frequency and identify factors associated with pre- and postoperative seizures in a large single-center population study of patients undergoing resection of supratentorial meningioma. METHODS: Retrospective chart review of 1033 subjects undergoing resection of supratentorial meningioma at the author's institution (1991-2014). Multivariate regression was used to identify variables significantly associated with pre- and postoperative seizures. RESULTS: Preoperative seizures occurred in 234 (22.7%) subjects. At 5 years postoperative, probability of seizure freedom was 89.9% among subjects without preoperative seizures and 62.2% with preoperative seizures. Multivariate analysis identified the following predictors of preoperative seizures: presence of ≥1 cm peritumoral edema (odds ratio [OR]: 4.45, 2.55-8.50), nonskull base tumor location (OR: 2.13, 1.26-3.67), greater age (OR per unit increase: 1.03, 1.01-1.05), while…

BACKGROUND: Although adult cervical spine deformity (ACSD) is associated with pain and disability, its health impact has not been quantified in comparison to other chronic diseases. OBJECTIVE: To perform a comparative analysis of the health impact of symptomatic ACSD to US normative and chronic disease values using EQ-5D (EuroQuol-5 Dimensions questionnaire) scores. METHODS: ACSD patients presenting for surgical treatment were identified from a prospectively collected multicenter database. Baseline demographics and EQ-5D scores were collected and compared with US normative and disease state values. RESULTS: Of 121 ACSD patients, 115 (95%) completed the EQ-5D (60% women, mean age 61 years, previous spine surgery in 44%). Diagnoses included kyphosis with mid-cervical (63.4%), cervico-thoracic (23.5%), or thoracic (8.7%) apex and primary coronal deformity (4.3%). The mean ACSD EQ-5D index was 0.511 (standard definition = 0.224), which is 34% below the bottom 25th percentile (0.780) for similar age- and gender-matched US normative populations. Mean ACSD EQ-5D index values were worse…

BACKGROUND: Several studies suggest significant variation in cost for spine surgery, but there has been little research in this area for spinal deformity. OBJECTIVE: To determine the utilization, cost, and factors contributing to cost for spinal deformity surgery. METHODS: The cohort comprised 55 599 adults who underwent spinal deformity fusion in the 2001 to 2013 National Inpatient Sample database. Patient variables included age, gender, insurance, median income of zip code, county population, severity of illness, mortality risk, number of comorbidities, length of stay, elective vs nonelective case. Hospital variables included bed size, wage index, hospital type (rural, urban nonteaching, urban teaching), and geographical region. The outcome was total hospital cost for deformity surgery. Statistics included univariate and multivariate regression analyses. RESULTS: The number of spinal deformity cases increased from 1803 in 2001 (rate: 4.16 per 100 000 adults) to 6728 in 2013 (rate: 13.9 per 100 000). Utilization of interbody fusion devices increased steadily during this time…

BACKGROUND: Hypothalamic hamartomas (HH) are rare lesions associated with treatment-resistant epilepsy. Open surgery results in modest seizure control (about 50%) but has a significant associated morbidity. Radiosurgery is limited to a subset of patients due to latent therapeutic effects. Magnetic resonance imaging-guided laser interstitial thermal therapy (LITT) offers a novel minimally invasive option. OBJECTIVE: To evaluate a single center's outcomes for the LITT treatment of HH. METHODS: We retrospectively reviewed our experience with LITT for the treatment of HH using our institution's prospectively maintained patient database. RESULTS: Eighteen patients (mean age, 21.1 yr; median age, 11 yr) underwent 21 total LITT treatments for HH. Mean follow-up was 17.4 mo. The length of stay was 1 night for 16 (89%) patients. At the end of follow-up, 11 of 18 patients (61%) had full disconnection of the HH, and 12 of 15 (80%) patients with gelastic seizures and 5 (56%) of 9 patients with nongelastic seizures were seizure free (International League Against Epilepsy Class 1). Immediate…

BACKGROUND: Microsurgical and endoscopic techniques are commonly utilized surgical approaches to pituitary pathologies. There are limited data comparing these 2 procedures. OBJECTIVE: To evaluate postoperative complications, associated costs, and national and regional trends of microscopic and endoscopic techniques in the United States employing a nationwide database. METHODS: The Truven MarketScan database 2010 to 2014 was queried and Current Procedural Terminology codes identified patients that underwent microscopic and/or endoscopic transsphenoidal pituitary surgery. International Classification of Diseases codes identified postoperative complications. Adjusted logistic regression and matched propensity analysis evaluated independent odds for complications. RESULTS: Among 5886 cases studied, 54.49% were microscopic and 45.51% endoscopic. The commonest surgical indications were benign pituitary tumors. Annual trends showed increasing utilization of endoscopic techniques vs microscopic procedures. Postoperative complications occurred in 40.04% of cases, including diabetes insipidus…

BACKGROUND: Annual incidence of symptomatic adjacent level disease (ALD) following lumbar fusion surgery ranges from 0.6% to 3.9% per year. Sagittal malalignment may contribute to the development of ALD. OBJECTIVE: To describe the relationship between pelvic incidence-lumbar lordosis (PI-LL) mismatch and the development of symptomatic ALD requiring revision surgery following single-level transforaminal lumbar interbody fusion for degenerative lumbar spondylosis and/or low-grade spondylolisthesis. METHODS: All patients who underwent a single-level transforaminal lumbar interbody fusion at either L4/5 or L5/S1 between July 2006 and December 2012 were analyzed for pre- and postoperative spinopelvic parameters. Using univariate and logistic regression analysis, we compared the spinopelvic parameters of those patients who required revision surgery against those patients who did not develop symptomatic ALD. We calculated the predictive value of PI-LL mismatch. RESULTS: One hundred fifty-nine patients met the inclusion criteria. The results noted that, for a 1° increase in PI-LL mismatch…

BACKGROUND: Guidelines regarding stereotactic radiosurgery (SRS) for brain metastases are missing recently published evidence. OBJECTIVE: To conduct a systematic review and provide an objective summary of publications regarding SRS in managing patients with 1 to 4 brain metastases. METHODS: Using Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, a systematic review was conducted using PubMed and Medline up to November 2016. A separate search was conducted for SRS for larger brain metastases. RESULTS: Twenty-seven prospective studies, critical reviews, meta-analyses, and published consensus guidelines were reviewed. Four key points came from these studies. First, there is no detriment to survival by withholding whole brain radiation (WBRT) in the upfront management of brain metastases with SRS. Second, while SRS on its own provides a high rate of local control (LC), WBRT may provide further increase in LC. Next, WBRT does provide distant brain control with less need for salvage therapy. Finally, the addition of WBRT does affect neurocognitive…

BACKGROUND: Quality improvement, value-based care delivery, and personalized patient care depend on robust clinical, financial, and demographic data streams of neurosurgical outcomes. The neurosurgical literature lacks a comprehensive review of large national databases. OBJECTIVE: To assess the strengths and limitations of various resources for outcomes research in neurosurgery. METHODS: A review of the literature was conducted to identify surgical outcomes studies using national data sets. The databases were assessed for the availability of patient demographics and clinical variables, longitudinal follow-up of patients, strengths, and limitations. RESULTS: The number of unique patients contained within each data set ranged from thousands (Quality Outcomes Database [QOD]) to hundreds of millions (MarketScan). Databases with both clinical and financial data included PearlDiver, Premier Healthcare Database, Vizient Clinical Data Base and Resource Manager, and the National Inpatient Sample. Outcomes collected by databases included patient-reported outcomes (QOD); 30-day morbidity,…

BACKGROUND: Although chronic hydrocephalus requiring shunt placement is a known sequela of aneurysmal subarachnoid hemorrhage (aSAH), its effect on long-term functional outcomes is incompletely understood. OBJECTIVE: To identify predictors of shunt-dependent hydrocephalus and shunt complications after aSAH and determine the effect of shunt dependence on functional outcomes in aSAH patients. METHODS: We evaluated a database of patients treated for aSAH at a single center from 2000 to 2015. Favorable and unfavorable outcomes were defined as modified Rankin Scale grades 0 to 2 and 3 to 6, respectively. We performed statistical analyses to identify variables associated with shunt-dependent hydrocephalus, unfavorable outcome, and shunt complication. RESULTS: Of the 888 aSAH patients, 116 had shunt-dependent hydrocephalus (13%). Older age (P = .001), intraventricular hemorrhage (IVH) (P = .004), higher World Federation of Neurological Surgeons (WFNS) grade (P < .001), surgical aneurysm treatment (P = .002), and angiographic vasospasm (P = .005) were independent predictors of…

BACKGROUND: Curative transvenous embolization is an emerging strategy for treatment of cerebral arteriovenous malformations (AVMs). OBJECTIVE: To assess contemporary outcomes of transvenous embolization as a stand-alone therapy for cerebral AVMs. METHODS: We prospectively followed 40 patients with 41 AVMs who underwent transvenous endovascular therapy between January 2008 and January 2015. Patient demographics, AVM characteristics, endovascular techniques used, angiographic results, clinical outcomes, and complications were assessed independently. RESULTS: Thirty-eight of 41 (92.6%) AVMs were anatomically cured. The mean patient age was 37.7 yr (range, 18-69 yr) and 55% were female. Twenty-seven (67.5%) patients presented with hemorrhage. The mean size of the AVM nidus was 2.8 ± 1.2 cm, and low Spetzler-Martin grade AVMs comprised 41.5% of lesions. The majority of patients were treated in 1 session (56%; n = 23). The mean follow-up period was 28.4 (range, 6-106 mo). There was 1 (2.5%) hemorrhagic complication related to microcatheter navigation and 1 (2.5%) venous infarction was…

BACKGROUND: The optimal therapeutic approach for adult craniopharyngioma remains controversial. Some advocate for gross total resection (GTR), while others advocate for subtotal resection followed by adjuvant radiotherapy (STR + XRT). OBJECTIVE: To conduct a systematic review and meta-analysis assessing the rate of recurrence in the follow-up of 3 yr in adult craniopharyngioma stratified by extent of resection and presence of adjuvant radiotherapy. METHODS: MEDLINE (1946-July 1, 2016) and EMBASE (1980-June 30, 2016) were systematically reviewed. From1975 to 2013, 33 patients were treated with initial surgical resection for adult onset craniopharyngioma at our center and were reviewed for inclusion in this study. RESULTS: Data from 22 patients were available for inclusion as a case series in the systematic review. Eligible studies (n = 21) were identified from the literature in addition to a case series of our institutional experience. Three groups were available for analysis: GTR, STR + XRT, and STR. The rates of recurrence were 17%, 27%, and 45%, respectively. The risk of…

QUESTION 1: What surgical approaches for vestibular schwannomas (VS) are best for complete resection and facial nerve (FN) preservation when serviceable hearing is present? RECOMMENDATION: There is insufficient evidence to support the superiority of either the middle fossa (MF) or the retrosigmoid (RS) approach for complete VS resection and FN preservation when serviceable hearing is present. QUESTION 2: Which surgical approach (RS or translabyrinthine [TL]) for VS is best for complete resection and FN preservation when serviceable hearing is not present? RECOMMENDATION: There is insufficient evidence to support the superiority of either the RS or the TL approach for complete VS resection and FN preservation when serviceable hearing is not present. QUESTION 3: Does VS size matter for facial and vestibulocochlear nerve preservation with surgical resection? RECOMMENDATION: Level 3: Patients with larger VS tumor size should be counseled about the greater than average risk of loss of serviceable hearing. QUESTION 4: Should small intracanalicular tumors (<1.5 cm) be surgically resected?…

BACKGROUND: Radiation-induced changes (RICs) are the most common complication of stereotactic radiosurgery (SRS) for brain arteriovenous malformations (AVMs), and they appear as perinidal T2-weighted hyperintensities on magnetic resonance imaging, with or without associated neurological symptoms. OBJECTIVE: To determine the rates of RIC after AVM SRS and identify risk factors. METHODS: A literature review was performed using PubMed and MEDLINE to identify studies reporting RIC in AVM patients treated with SRS. RICs were classified as radiologic (any neuroimaging evidence), symptomatic (any associated neurological deterioration, regardless of duration), and permanent (neurological decline without recovery). Baseline, treatment, and outcomes data were extracted for statistical analysis. RESULTS: Based on pooled data from 51 studies, the overall rates of radiologic, symptomatic, and permanent RIC after AVM SRS were 35.5% (1143/3222 patients, 32 studies), 9.2% (499/5447 patients, 46 studies), and 3.8% (202/5272 patients, 39 studies), respectively. Radiologic RIC was significantly…

BACKGROUND: Modern-day stereotactic techniques have evolved to tackle the neurosurgical challenge of accurately and reproducibly accessing specific brain targets. Neurosurgical advances have been made in synergy with sophisticated technological developments and engineering innovations such as automated robotic platforms. Robotic systems offer a unique combination of dexterity, durability, indefatigability, and precision. OBJECTIVE: To perform a systematic review of robotic integration for cranial stereotactic guidance in neurosurgery. Specifically, we comprehensively analyze the strengths and weaknesses of a spectrum of robotic technologies, past and present, including details pertaining to each system's kinematic specifications and targeting accuracy profiles. METHODS: Eligible articles on human clinical applications of cranial robotic-guided stereotactic systems between 1985 and 2017 were extracted from several electronic databases, with a focus on stereotactic biopsy procedures, stereoelectroencephalography, and deep brain stimulation electrode insertion. RESULTS: Cranial robotic…

Question: What are the indications for stereotactic radiosurgery (SRS) treatment vs observation for patients with intracanalicular vestibular schwannomas without evidence of radiographic progression? Recommendation: Level 3: If tinnitus is not observed at presentation, it is recommended that intracanalicular vestibular schwannomas and small tumors (<2 cm) without tinnitus be observed as observation does not have a negative impact on tumor growth or hearing preservation compared to treatment. Question: Is there a difference in outcome based on radiosurgery equipment used: Gamma Knife (Elekta, Stockholm, Sweden) vs linear accelerator-based radiosurgery vs proton beam? Recommendation: There are no studies that compare 2 or all 3 modalities. Thus, recommendations on outcome based on modality cannot be made. Question: Is there a difference in outcome based on the dose delivered? Recommendation: Level 3: As there is no difference in radiographic control using different doses, it is recommended that for single fraction SRS doses, <13 Gy be used to facilitate hearing preservation and…

Surgery for spinal metastases remains the mainstay treatment for pain, instability, and neurological deterioration due to tumor infiltration of the spine. However, several new therapies are emerging which may improve outcomes further, and in some cases even replace the need for surgery. We now have a better understanding of which factors influence survival and quality of life after surgery, and this underpins the development and application of new treatments, and assessment of outcome.Depending on genetic subtyping of tumors, novel immunotherapies and chemotherapies may be very effective in prolonging quality of life. New surgical techniques allow smaller, quicker, and safer operations with less blood loss, pain, and quicker recovery after surgery. Radiation treatments have also leapt forward with the greater accuracy and higher doses possible from intensity-modulated photon radiation, stereotactic body radiation treatment, proton beam therapy, or carbon ion treatment. Combined with more advanced materials for vertebral body stabilization, computer navigation systems, and robotics,…

BACKGROUND: Long-term remission rates from endoscopic transsphenoidal surgery for acromegaly and their relationship to prognostic indicators of disease aggressiveness are not well documented. OBJECTIVE: To investigate long-term remission rates in patients with acromegaly after endoscopic transsphenoidal surgery, and correlate this with molecular and radiographic markers of disease aggressiveness. METHODS: We identified all patients undergoing endoscopic transsphenoidal surgery for acromegaly from 2005 to 2013 at Cedars-Sinai Pituitary Center. Hormonal remission was established by normal insulin-like growth factor (IGF)-1, basal serum growth hormone <2.5 ng/mL, and growth hormone suppression to <1 ng/mL following oral glucose tolerance test. Oral glucose tolerance test was performed at 3 months after surgery, and then as indicated. IGF-1 was measured at 3 months and then at least annually. We evaluated tumor granularity, nuclear expression of p21, Ki67 index, and extent of cavernous sinus invasion, and correlated these with remission status. RESULTS: Fifty-eight patients that…

QUESTION 1: What sequences should be obtained on magnetic resonance imaging (MRI) to evaluate vestibular schwannomas before and after surgery? TARGET POPULATION: Adults with vestibular schwannomas. RECOMMENDATIONS: Initial Preoperative Evaluation Level 3: Imaging used to detect vestibular schwannomas should use high-resolution T2-weighted and contrast-enhanced T1-weighted MRI. Level 3: Standard T1, T2, fluid attenuated inversion recovery, and diffusion weighted imaging MR sequences obtained in axial, coronal, and sagittal plane may be used for detection of vestibular schwannomas. Preoperative Surveillance Level 3: Preoperative surveillance for growth of a vestibular schwannoma should be followed with either contrast-enhanced 3-dimensional (3-D) T1 magnetization prepared rapid acquisition gradient echo (MPRAGE) or high-resolution T2 (including constructive interference in steady state [CISS] or fast imaging employing steady-state acquisition [FIESTA] sequences) MRI. Postoperative Evaluation Level 2: Postoperative evaluation should be performed with postcontrast 3-D T1 MPRAGE, with…

BACKGROUND: In minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF), cage type and position play important roles in fusion achievement and sagittal alignment correction. However, no prospective randomized comparison of the results using different types of cage has been reported to date. OBJECTIVE: To compare the radiological and clinical outcomes of unilateral MIS-TLIF using 2 types of cage. METHODS: All candidates for single-level MIS-TLIF were randomized into banana-shaped cage and straight-cage groups. Plain radiographs and computed tomography scans were used for assessment of cage positions, fusion status, disc height, segmental lordotic angle, cage subsidence, and pelvic parameters. Clinical outcome was assessed using visual analog scale and Oswestry Disability Index scores. RESULTS: Forty-four and 40 consecutive patients were operated on using banana-shaped and straight cages, respectively. Cage position was more anterior and lateral in the straight-cage group and more medial and posterior in the banana-shaped cage group. Solid fusion was achieved in 95.2% and…

BACKGROUND: The safety and probable benefit of the PulseRider (Pulsar Vascular, Los Gatos, California) for the treatment of broad-necked, bifurcation aneurysms was studied in the context of the prospective, nonrandomized, single arm clinical trial-the Adjunctive Neurovascular Support of Wide-neck aneurysm Embolization and Reconstruction (ANSWER) Trial. OBJECTIVE: To present the results of the United States cases employing the PulseRider device as part of the ANSWER clinical trial. METHODS: Aneurysms treated with the PulseRider device among sites enrolling in the ANSWER trial were prospectively studied and the results are summarized. Aneurysms arising at either the carotid terminus or basilar apex that were relatively broad necked were considered candidates for inclusion into the ANSWER study. RESULTS: Thirty-four patients were enrolled (29 female and 5 male) with a mean age of 60.9 years (27 basilar apex and 7 carotid terminus). Mean aneurysm height ranged from 2.4 to 15.9 mm with a mean neck size of 5.2 mm (range 2.3-11.6 mm). In all patients, the device was delivered and deployed.…