Search

Spinal anesthesia (SA) has been utilized for lumbar surgical procedures; however, postdural puncture headache (PDPH) and subdural hemorrhage (SDH) are potential consequences. We present the case of a 76-year-old with progressive neurogenic claudication secondary to lumbar spinal stenosis who received SA for a 2-level lumbar posterior decompression. After decompression, the site of dural puncture from a 24-gauge Sprotte spinal needle was identified. Our intraoperative image demonstrates the submillimeter dural defect that can potentially engender complications as significant as PDPH and/or SDH. We recommend searching for, and preemptively sealing, the dural puncture site when SA is used for lumbar spine surgery.

Background Machine learning (ML)-based predictive models are increasingly common in neurosurgery, but typically require large databases of discrete variables for training. Natural language processing (NLP) can extract meaningful data from unstructured text. Objective To present an NLP model that predicts nonhome discharge and a point-of-care implementation. Methods We retrospectively collected age, preoperative notes, and radiology reports from 595 adults who underwent meningioma resection in an academic center from 1995 to 2015. A total of 32 algorithms were trained with the data; the 3 best performing algorithms were combined to form an ensemble. Predictive ability, assessed by area under the receiver operating characteristic curve (AUC) and calibration, was compared to a previously published model utilizing 52 neurosurgeon-selected variables. We then built a multi-institutional model by incorporating notes from 693 patients at another center into algorithm training. Permutation importance was used to analyze the relative importance of each input to model performance. Word clouds and non-negative matrix factorization were used to analyze predictive features of text. Results The single-institution NLP model predicted nonhome discharge with AUC of 0.80 (95% CI = 0.74-0.86) on internal and 0.76 on holdout validation compared to AUC of 0.77 (95% CI = 0.73-0.81) and 0.74 for the 52-variable ensemble. The multi-institutional model performed similarly well with AUC = 0.78 (95% CI = 0.74-0.81) on internal and 0.76 on holdout validation. Preoperative notes most influenced predictions. The model is available at http://nlp-home.insds.org. Conclusion ML and NLP are underutilized in neurosurgery. Here, we construct a multi-institutional NLP model that predicts nonhome discharge.

BACKGROUND CONTEXT Complex spine surgery carries a high complication rate that can produce suboptimal outcomes for patients undergoing these extensive operations. However, multidisciplinary pathways introduced at multiple institutions have demonstrated a promising potential towards reducing the burden of complications in patients being treated for spinal deformities. To date, there has been no effort to systematically collate the multidisciplinary approaches in use at various institutions. PURPOSE The present study aims to determine effective multidisciplinary strategies for reducing the complication rate in complex spine surgery by analyzing existing institutional multidisciplinary approaches and delineating common themes across multiple practice settings. STUDY DESIGN Systematic review. METHODS We followed guidelines established under the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The studies reported on data from PubMed, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Science and Cochrane. We included articles that described either approaches to, or results from, the implementation of multidisciplinary paradigms during the pre-operative, peri-operative, and post-operative phases of care for patients undergoing complex spine surgery. We excluded studies that only targeted one complication unless such an approach was in coordination with more extensive multidisciplinary planning at the same institution. RESULTS A total of 406 unique articles were identified. Following an initial determination based on title and abstract, 22 articles met criteria for full-text review, and 10 met the inclusion criteria to be included in the review. Key aspects of multidisciplinary approaches to complex spine surgery included extensive pre-operative workup and interdisciplinary conferencing, intra-operative communication and monitoring, and post-operative floor management and discharge planning. These strategies produced decreases in surgical duration and complication rates. CONCLUSIONS This study represents the first to systematically analyze multidisciplinary approaches to reduce complications in complex spine surgery. This review provides a roadmap towards reducing the elevated complication rate for patients undergoing complex spine surgery.

T-cell dysfunction contributes to tumor immune escape in patients with cancer and is particularly severe amidst glioblastoma (GBM). Among other defects, T-cell lymphopenia is characteristic, yet often attributed to treatment. We reveal that even treatment-naïve patients and mice with GBM can harbor AIDS-level CD4 counts, as well as contracted, T-cell deficient lymphoid organs. Missing naïve T-cells are instead found sequestered in large numbers in the bone marrow. This phenomenon characterizes not only GBM but a variety of other cancers, although only when tumors are introduced into the intracranial compartment. T-cell sequestration is accompanied by tumor-imposed loss of S1P1 from the T-cell surface and is reversible upon precluding S1P1 internalization. In murine models of GBM, hindering S1P1 internalization and reversing sequestration licenses T-cell-activating therapies that were previously ineffective. Sequestration of T-cells in bone marrow is therefore a tumor-adaptive mode of T-cell dysfunction, whose reversal may constitute a promising immunotherapeutic adjunct.

The use of intraoperative image guided navigation (NAV) in spine surgery is increasing. NAV is purported to improve the accuracy of pedicle screw placement but has been criticized for potentially increasing surgical cost, a component of which may be prolongation of total operative time due to time required for setup and intra-operative imaging and registration. In this study, we examine the effect of the introduction of O-Arm conical CT spinal navigation on surgical duration. We retrospectively analyzed consecutive freehand (FH) (n=63) and NAV (n=70) 1-level lumbar transpedicular instrumentation cases at a single institution by a single surgeon. We recorded setup and procedure time for each case. NAV was associated with significantly shorter total operative time for 1-level lumbar fusions compared to FH (4:30+/-0:42 hours vs. 4:53+/-0:39hours, p=0.0013). This shortening of total operative time was realized despite a trend toward slightly longer setup times with NAV. We also found a significant decrease in operative length over time in NAV but not FH cases, indicative of a "learning curve" associated with NAV. The use of NAV in 1-level lumbar transpedicular instrumentation surgery is associated with significantly shorter total operative time compared to the FH technique, and its efficiency improves over time. These data should factor into cost-effectiveness analyses of the use of NAV for these cases.

Background:We present a rare case of comorbid relapsed acute myeloid leukemia (AML) with the involvement of the central nervous system (CNS) and subdural seeding of vancomycin-resistantEnterococcusfaecium(VRE). The safety profile, treatment approach with pharmacokinetic considerations, and evaluation of success for bilateral subdural administration of daptomycin after subdural hematoma (SDH) are assessed.Case Description:A 45-year-old male with a history of AML who underwent chemotherapy (induction with 7 + 3) was admitted to oncology with relapsed AML confirmed by bone marrow biopsy, complicated by neutropenic fever and VRE bacteremia. After acute neurological changes with image confirmation of mixed- density bilateral SDHs secondary to thrombocytopenia, the patient was admitted to the neurosurgery unit and underwent bilateral burr hole craniotomies for subdural evacuation with the placement of the left and right subdural drains. Culture of the subdural specimen confirmed VRE seeding of the subdural space. The patient received the first dose of daptomycin into the bilateral subdural spaces 2 days after evacuation and was noted to have acute improvement on neurological examination, followed by a second administration to the left subdural space 5 days after evacuation with bilateral drains pulled thereafter.Conclusion:In this patient, the complication of relapsed AML may have contributed to the rare extension of VRE into the CNS space. Screening for patients at risk of AML with CNS involvement and addressing coagulopathy and risk of infection may help mitigate morbidity. Bilateral administration of subdural daptomycin bolus into the subdural space was tolerated and possibly contributed to the patient’s neurological improvement during an extended hospital course.

In the version of this article originally published, the figure callout in this sentence was incorrect: “Furthermore, in S1P1-KI mice themselves, whereas PD-1 blockade was ineffectual as monotherapy, the effects of 4-1BB agonism and checkpoint blockade proved additive, with the combination prolonging median survival and producing a 50% long-term survival rate (Fig. 6f).” The callout should have been to Supplementary Fig. 6b. The error has been corrected in the PDF and HTML versions of the article.

OBJECTIVE To determine whether patients who learned the views of an expert surgeons' panel's assessment of equipoise between 2 alternative operative treatments had increased likelihood of consenting to randomization. BACKGROUND Difficulty obtaining patient consent to randomization is an important barrier to conducting surgical randomized clinical trials, the gold standard for generating clinical evidence. METHODS Observational study of the rate of patient acceptance of randomization within a 5-center randomized clinical trial comparing lumbar spinal decompression versus lumbar spinal decompression plus instrumented fusion for patients with symptomatic grade I degenerative lumbar spondylolisthesis with spinal stenosis. Eligible patients were enrolled in the trial and then asked to accept randomization. A panel of 10 expert spine surgeons was formed to review clinical information and images for individual patients to provide an assessment of suitability for randomization. The expert panel vote was disclosed to the patient by the patient's surgeon before the patient decided whether to accept randomization or not. RESULTS Randomization acceptance among eligible patients without expert panel review was 40% (19/48) compared with 81% (47/58) among patients undergoing expert panel review (P

BackgroundThe comparative effectiveness of performing instrumented (rigid pedicle screws affixed to titanium alloy rods) lumbar spinal fusion in addition to decompressive laminectomy in patients with symptomatic lumbar grade I degenerative spondylolisthesis with spinal stenosis is unknown. MethodsIn this randomized, controlled trial, we assigned patients, 50 to 80 years of age, who had stable degenerative spondylolisthesis (degree of spondylolisthesis, 3 to 14 mm) and symptomatic lumbar spinal stenosis to undergo either decompressive laminectomy alone (decompression-alone group) or laminectomy with posterolateral instrumented fusion (fusion group). The primary outcome measure was the change in the physical-component summary score of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36; range, 0 to 100, with higher scores indicating better quality of life) 2 years after surgery. The secondary outcome measure was the score on the Oswestry Disability Index (range, 0 to 100, with higher scores i...

BACKGROUND AND IMPORTANCE Syringomyelia is highly associated with Chiari I malformation, but the pathophysiologic mechanism of syrinx formation and its relation to downward cerebellar tonsillar displacement remains elusive. Cough, Valsalva maneuver, and other physiological strains transiently exacerbate the clinical symptoms of these conditions, exert profound effects on the flow dynamics across the craniospinal junction, and are thought to play an important role in the pathogenesis of syringomyelia. CLINICAL PRESENTATION We report the case of a patient with cystic fibrosis who presented during an exacerbation of bronchiectasis and was found to have a Chiari I malformation with associated syringomyelia. Eight months later, when the patient had returned to baseline pulmonary status, repeat imaging showed interval improvement in both the size of the syrinx and descent of cerebellar tonsils. CONCLUSION This rare case of spontaneous improvement of syringomyelia and Chiari I malformation attributable to relief from chronic cough offers interesting insight into the mechanism of these disorders. ABBREVIATIONS FEV1, forced expiratory volume in 1 secondFVC, forced vital capacity.

Objective Lumbar spondylolisthesis can be related to facet arthropathy and disc degeneration or to a fracture of the pars interarticularis, but the mechanistic underpinnings of spondylolisthesis remain unclear. We posit that high sacral slope and body weight increase sacral inclination vector forces, which leads to pars fractures and exacerbates risk for spondylolisthesis. Methods To investigate this hypothesis, we measured the sacral slope, body weight, and S1 endplate vector forces for patients who underwent L5–S1 fusion for grade I spondylolisthesis. Patients were stratified based on presence of pars fractures versus facet arthropathy, and statistical analyses were performed to determine whether high sacral endplate inclination vector force is associated with pars fracture–mediated spondylolisthesis. Results We identified 131 patients who had L5–S1 fusion for spondylolisthesis. The mean age was 56 years, and 57% were female. The body weight of patients ranged from 45.4 to 141.9 kg with an average of 83.8 kg; 32 patients had single-level L5–S1 spondylolisthesis secondary to bilateral L5 pars interarticularis fractures, whereas 99 patients had L5–S1 spondylolisthesis due to facet arthropathy. Patients with pars fractures had steeper sacral slopes (43.2 ± 10.1°) compared with those without pars fractures (36.8 ± 8.1°) (P = 0.0007, odds ratio 2.71). Despite having no significant differences in weight (82.7 ± 17.2 vs. 87.3 ± 17.2 kg, P = 0.189), patients with pars fractures had 49% greater sacral inclination vector forces compared with those without pars fractures (586 ± 158 N vs. 394 ± 90 N, P Conclusions These data suggest that high sacral endplate inclination vector force is a risk factor for developing pars fracture–mediated spondylolisthesis.

Although the pre-surgical management of patients with acute traumatic subdural hematoma prioritizes rapid transport to the operating room, there is conflicting evidence regarding the importance of time interval from injury to surgery with regards to outcomes. We sought to determine the association of surgical timing with outcomes for subdural hematoma. A retrospective review was performed of 522 consecutive patients admitted to a single center from 2006–2012 who underwent emergent craniectomy for acute subdural hematoma. After excluding patients with unknown time of injury, penetrating trauma, concurrent cerebrovascular injury, epidural hematoma, or intraparenchymal hemorrhage greater than 30 mL, there remained 45 patients identified for analysis. Using a multiple regression model, we examined the effect of surgical timing, in addition to other variables on in-hospital mortality (primary outcome), as well as the need for tracheostomy or gastrostomy (secondary outcome). We found that increasing injury severity score (odds ratio [OR] 1.146; 95% confidence interval [CI] 1.035–1.270; p = 0.009) and age (OR1.066; 95%CI 1.006–1.129; p = 0.031) were associated with in-hospital mortality in multivariate analysis. In this model, increasing time to surgery was not associated with mortality, and in fact had a significant effect in decreasing mortality (OR 0.984; 95%CI 0.971–0.997; p = 0.018). Premorbid aspirin use was associated with a paradoxical decrease in mortality (OR 0.019; 95%CI 0.001–0.392; p = 0.010). In this patient sample, shorter time interval from injury to surgery was not associated with better outcomes. While there are potential confounding factors, these findings support the evaluation of rigorous preoperative resuscitation as a priority in future study.

Lumbar disc herniations are common. In cases where significant symptoms persist after attempted non-operative treatment, a discectomy is indicated. Do different surgical techniques affect the long-term outcome? Surgical techniques have evolved since the early days of lumbar disc excision.1 Advances in optics and illumination have allowed surgeons to gain access to the disc fragment with smaller incisions, and laminectomy has given way to unilateral laminotomy. As the trend towards smaller incisions and less bone removal continues, it is helpful to consider whether any differences in outcome will emerge and whether conventional microdiscectomy can be made safer. In this vein, the study by Overdevest et al provides a much needed addition to the spinal literature.2 In this study, the authors report on the 5-year follow-up results of a trial comparing tubular discectomy to conventional discectomy.3 The present study is …

OBJECTIVE Vascular malformations of the spine represent rare clinical entities with profound neurological implications. Previously reported studies on management strategies for spinal dural arteriovenous fistulas (sDAVFs) appeared before the advent of modern liquid embolic agents. Authors of the present study review their institutional experience with endovascularly and surgically treated sDAVFs. METHODS The authors performed a retrospective, observational, single-center case series on sDAVFs treated with endovascular embolization, microsurgical occlusion, or both between 2004 and 2013. The mode, efficacy, and clinical effect of treatment were evaluated. RESULTS Forty-seven patients with spinal arteriovenous malformations were evaluated using spinal angiography, which demonstrated 34 Type I sDAVFs (thoracic 20, lumbar 12, and cervical 2). Twenty-nine of the patients (85%) were male, and the median patient age was 63.3 years. Twenty patients underwent primary endovascular embolization (16 Onyx, 4 N-butyl cyanoacrylate [NBCA]), and 14 underwent primary surgical clipping. At a mean follow-up of 36 weeks, according to angiography or MR angiography, 5 patients treated with endovascular embolization demonstrated persistent arteriovenous shunting, whereas none of the surgically treated patients showed lesion persistence (p = 0.0237). Thirty patients (88%) experienced some resolution of their presenting symptoms (embolization 17 [85%], surgery 13 [93%], p = 1.00). CONCLUSIONS Microsurgical occlusion remains the most definitive treatment modality for sDAVFs, though modern endovascular techniques remain a viable option for the initial treatment of anatomically amenable lesions. Treatment of these lesions usually results in some clinical improvement.

Object Dural closure with synthetic grafts has been suggested to contribute to the incidence of infection and CSF leak. The objective of this study was to assess the contribution of choice of dural closure material, as well as other factors, to the incidence of infection and CSF leak. Methods A retrospective, consecutive cohort study of adult patients undergoing elective craniotomy was established between April 2010 and March 2011 at a single center. Exclusion criteria consisted of trauma, bur hole placement alone, and temporary CSF fluid diversion. Results Three hundred ninety-nine patients were included (mean follow-up 396.6 days). Nonautologous (synthetic) dural substitute was more likely to be used (n = 106) in cases of reoperation (p = 0.001). Seventeen patients developed a surgical site infection and 12 patients developed a CSF leak. Multivariate logistic regression modeling identified estimated blood loss (OR 1.002, 95% CI 1.001–1.003; p < 0.001) and cigarette smoking (OR 2.198, 95% CI 1.109–4.238; p = 0.019) as significant predictors of infection. Synthetic dural graft was not a predictor of infection in multivariate analysis. Infratentorial surgery (OR 4.348, 95% CI 1.234–16.722; p = 0.024) and more than 8 days of postoperative corticosteroid treatment (OR 3.886, 95% CI 1.052–16.607; p = 0.048) were significant predictors for the development of CSF leak. Synthetic dural graft was associated with a lower likelihood of CSF leak (OR 0.072, 95% CI 0.003–0.552; p = 0.036). Conclusions The use of synthetic dural closure material is not associated with surgical site infection and is associated with a reduced incidence of CSF leak. Modifiable risk factors exist for craniotomy complications that warrant vigilance and further study.

Background Atlantoaxial instability, which can arise in the setting of trauma, degenerative diseases, and neoplasm, is often managed surgically with C1-C2 arthrodesis. Classical C1-C2 fusion techniques require placement of instrumentation in close proximity to the vertebral artery and C2 nerve root. Objective To report a novel C1-C2 fusion technique that utilizes C2 translaminar screws and C1 sublaminar cables to decrease the risk of injury to the vertebral artery and C2 nerve root. Methods To facilitate fixation to the atlas, while minimizing the risk of injury to the vertebral artery and to the C2 nerve root, we sought to determine the feasibility of using a soft cable around the C1 arch and affixing it to a rod connected to C2 laminar screws. We reviewed our experience in 3 patients. Results We used this technique in patients in whom we anticipated difficult C1 screw placement. Three patients were identified through a review of the senior author's cases. Atlantoaxial instability was associated with trauma in 2 patients and chronic degenerative changes in 1 patient. Common symptoms on presentation included pain and limited range of motion. All patients underwent C1-C2 fusion with C2 translaminar screws with sublaminar cable harnessing of the posterior arch of C1. There were no reports of postoperative complications or hardware failure. Conclusion We demonstrate a novel, technically straightforward approach for C1-C2 fusion that minimizes risk to the vertebral artery and to the C2 nerve root, while still allowing for semirigid fixation in instances of both traumatic and chronic degenerative atlantoaxial instability.

Study objectiveAnesthesiologists at our hospital commonly administer spinal anesthesia for routine lumbar spine surgeries. Anecdotal impressions suggested that patients received fewer anesthesia-administered intravenous medications, including vasopressors, during spinal versus general anesthesia. We hypothesized that data review would confirm these impressions. The objective was to test this hypothesis by comparing specific elements of spinal versus general anesthesia for 1-2 level open lumbar spine procedures.DesignRetrospective single institutional study.SettingAcademic medical center, operating rooms.PatientsConsecutive patients (144 spinal and 619 general anesthesia) identified by automatic structured query of our electronic anesthesia record undergoing lumbar decompression, foraminotomy or microdiscectomy by one surgeon under general or spinal anesthesia.InterventionsSpinal or general anesthesia.MeasurementsNumbers of medications administered during the case.Main resultsAnesthesiologists administered in the operating room a total of 10 ± 2 intravenous medications for general anesthetics and 5 ± 2 medications for spinal anesthetics (-5, 95% CI -5 to -4, pConclusionsFor routine lumbar surgery in our cohort, spinal compared to general anesthesia was associated with significantly fewer drugs administered during a case and less frequent use of vasoactive agents. Safety implications include greater hemodynamic stability with spinal anesthesia along with reduced risks for medication error and transmission of pathogens associated with medication administration.

Spinal nerve root metastasis of renal cell carcinoma is a rare occurrence. In addition to treatment of the primary lesion, surgical resection of the nerve root metastasis, occasionally with sacrifice of the involved nerve, is the accepted standard of treatment. Resection often resolves presenting motor and pain symptoms due to relief of neural compression. We describe two patients with nerve root metastasis of renal cell carcinoma and their management. While locally advanced and metastatic renal cell carcinoma has been shown to be chemo- and radio-resistant, immunotherapy is a promising treatment. Given the high prevalence of systemic disease in patients with intradural metastases, systemic (and possibly intracranial) imaging can be used to identify other potential areas of disease.

Object It is not known whether adding fusion to lumbar decompression is necessary for all patients undergoing surgery for degenerative lumbar spondylolisthesis with symptomatic stenosis. Determining specific radiographic traits that might predict delayed instability following decompression surgery might guide clinical decision making regarding the utility of up-front fusion in patients with degenerative Grade I spondylolisthesis. Methods Patients with Grade I degenerative lumbar spondylolisthesis (3–14 mm) with symptomatic stenosis were prospectively enrolled from a single site between May 2002 and September 2009 and treated with decompressive laminectomy without fusion. Patients with mechanical back pain or with gross motion (> 3 mm) on flexion-extension lumbar radiographs were excluded. The baseline radiographic variables measured included amount of slippage, disc height, facet angle, motion at spondylolisthesis (flexion-extension), and sagittal rotation angle. Data were analyzed using multivariate forward selection stepwise logistic regression, chi-square tests, Student t-test, and ANOVA. Results Forty patients were enrolled and treated with laminectomy without fusion, and all patients had complete radiographic data sets that were available for analysis. Reoperation was performed in 15 (37.5%) of 40 patients, with a mean follow-up duration of 3.6 years. Reoperation was performed for pain caused by instability at the index level in all 15 cases. Using multivariate stepwise logistic regression with a threshold p value of 0.35, motion at spondylolisthesis, disc height, and facet angle were predictors of reoperation following surgery. Facet angle > 50° was associated with a 39% rate of reoperation, disc height > 6.5 mm was associated with a 45% rate of reoperation, and motion at spondylolisthesis > 1.25 mm was associated with a 54% rate of reoperation. Patients with all 3 risk factors for instability had a 75% rate of reoperation, whereas patients with no risk factors for instability had a 0% rate of reoperation (p = 0.14). Conclusions Patients with motion at spondylolisthesis > 1.25 mm, disc height > 6.5 mm, and facet angle > 50° are more likely to experience instability following decompression surgery for Grade I lumbar spondylolisthesis. Identification of key risk factors for instability might improve patient selection for decompression without fusion surgery. Clinical trial registration no.: NCT00109213

Object Decompressive craniectomy mandates subsequent cranioplasty. Complications of cranioplasty may be independent of the initial craniectomy, or they may be contingent upon the craniectomy. Authors of this study aimed to identify surgery- and patient-specific risk factors related to the development of surgical site infection and other complications following cranioplasty. Methods A consecutive cohort of patients of all ages and both sexes who had undergone cranioplasty following craniectomy for stroke or trauma at a single institution in the period from May 2004 to May 2012 was retrospectively established. Patients who had undergone craniectomy for infectious lesions or neoplasia were excluded. A logistic regression analysis was performed to model and predict determinants related to infection following cranioplasty. Results Two hundred thirty-nine patients met the study criteria. The overall rate of complication following cranioplasty was 23.85% (57 patients). Complications included, predominantly, surgical site infection, hydrocephalus, and new-onset seizures. Logistic regression analysis identified previous reoperation (OR 3.25, 95% CI 1.30–8.11, p = 0.01) and therapeutic indication for stroke (OR 2.45, 95% CI 1.11–5.39, p = 0.03) as significantly associated with the development of cranioplasty infection. Patient age, location of cranioplasty, presence of an intracranial device, bone flap preservation method, cranioplasty material, booking method, and time interval > 90 days between initial craniectomy and cranioplasty were not predictive of the development of cranioplasty infection. Conclusions Cranioplasty complications are common. Cranioplasty infection rates are predicted by reoperation following craniectomy and therapeutic indication (stroke). These variables may be associated with patient-centered risk factors that increase cranioplasty infection risk.

Cerebral edema develops in response to and as a result of a variety of neurologic insults such as ischemic stroke, traumatic brain injury, and tumor. It deforms brain tissue, resulting in localized mass effect and increase in intracranial pressure (ICP) that are associated with a high rate of morbidity and mortality. When administered in bolus form, hyperosmolar agents such as mannitol and hypertonic saline have been shown to reduce total brain water content and decrease ICP, and are currently the mainstays of pharmacological treatment. However, surprisingly, little is known about the increasingly common clinical practice of inducing a state of sustained hypernatremia. Herein, we review the available studies employing sustained hyperosmolar therapy to induce hypernatremia for the prevention and/or treatment of cerebral edema. Insufficient evidence exists to recommend pharmacologic induction of hypernatremia as a treatment for cerebral edema. The strategy of vigilant avoidance of hyponatremia is currently a safer, potentially more efficacious paradigm.

Performing neurological surgery is an inherently demanding task on the human body, both physically and mentally. Neurosurgeons routinely perform "high stakes" operations in the setting of mental and physical fatigue. These conditions may be not only the result of demanding operations, but also influential to their outcome. Similar to other performance-based endurance activities, training is paramount to successful outcomes. The inflection point, where training reaches the point of diminishing returns, is intensely debated. For the neurosurgeon, this point must be exploited to the maximum, as patients require both the best-trained and best-performing surgeon. In this review, we explore the delicate balance of training and performance, as well as some routinely used adjuncts to improve human performance.

Chordoma is a rare bone cancer that is aggressive, locally invasive, and has a poor prognosis. Chordomas are thought to arise from transformed remnants of notochord and have a predilection for the axial skeleton, with the most common sites being the sacrum, skull base, and spine. The gold standard treatment for chordomas of the mobile spine and sacrum is en-bloc excision with wide margins and postoperative external-beam radiation therapy. Treatment of clival chordomas is unique from other locations with an enhanced emphasis on preservation of neurological function, typified by a general paradigm of maximally safe cytoreductive surgery and advanced radiation delivery techniques. In this Review, we highlight current standards in diagnosis, clinical management, and molecular characterisation of chordomas, and discuss current research.

STUDY DESIGN Surgeons attending a Cervical Spine Research Society (CSRS) meeting were surveyed about the surgical approach to cervical spondylotic myelopathy (CSM). OBJECTIVE To elicit spine surgeons' opinions on the suitability of a panel of test cases for randomization in a proposed randomized controlled trial (RCT) of ventral versus dorsal decompression for CSM. SUMMARY OF BACKGROUND DATA The optimal surgical decompression strategy for CSM has not been defined. Specific eligibility criteria should be defined before a RCT is initiated. METHODS Twenty actual cases with images were prepared. Surgeons supplied demographic information, preferred surgical approach, and eligibility for randomization for 10 cases. RESULTS A total of 91 of 239 (38%) surgeons completed the survey. Of 900 case-strategy responses, 51% recommended ventral surgery, 38% dorsal surgery, and 11% a combined approach. Both overall C2-C7 kyphosis >5 degrees and a segmental kyphotic deformity were inversely correlated with eligibility for randomization (P < 0.001 for both). Using these 2 criteria plus age over 85 years, ossification of the posterior longitudinal ligament, and congenital canal stenosis as additional exclusion criteria, 12 of 20 survey cases were considered potentially eligible for randomization. Orthopedic and neurologic surgeons were similar in determining a case's eligibility for randomization. CONCLUSIONS These results measure surgeons' opinions on the suitability of cases for randomization and help to define entry and exclusion criteria for a RCT comparing ventral to dorsal strategies. Over 50% of CSM cases from a general spinal practice might be eligible for randomization.

Cervical radiculopathy is a common condition that usually results from compression and inflammation of the cervical nerve root or roots in the region of the neural foramen. It is frequently caused by cervical disc herniation and cervical spondylosis. The diagnosis can be established by history and physical examination, but care should be taken, as diagnoses can mimic or coexist with cervical radiculopathy, such as entrapment neuropathies. The pathophysiology, presentation, and clinical evaluation of cervical radiculopathy are discussed.

Neurosurgeons encounter a number of pigmented tumors of the central nervous system in a variety of locations, including primary central nervous system melanoma, blue nevus of the spinal cord, and melanotic schwannoma. When examined through the lens of embryology, pigmented lesions share a unifying connection: They occur in structures that are neural crest cell derivatives. Here, we review the important progress made in the embryology of neural crest cells, present 3 cases of pigmented tumors of the nervous system, and discuss these clinical entities in the context of the development of melanoblasts. Pigmented lesions of the nervous system arise along neural crest cell migration routes and from neural crest-derived precursors. Awareness of the evolutionary clues of vertebrate pigmentation by the neurosurgical and neuro-oncological community at large is valuable for identifying pathogenic or therapeutic targets and for designing future research on nervous system pigmented lesions. When encountering such a lesion, clinicians should be aware of the embryological basis to direct additional evaluation, including genetic testing, and to work with the scientific community in better understanding these lesions and their relationship to neural crest developmental biology.

Background: Cranioplasty encompasses various cranial reconstruction techniques that are used following craniectomy due to stroke or trauma. Despite classical infectious signs, symptoms, and radiologic findings, however, the diagnosis of infection following cranioplasty can be elusive, with the potential to result in definitive treatment delay. We sought to determine if fever or leukocytosis at presentation were indicative of infection, as well as to identify any factors that may limit its applicability. Methods: Following institutional review board approval, a retrospective cohort of 239 patients who underwent cranioplasty following craniectomy for stroke or trauma was established from 2001-2011 at a single center (Massachusetts General Hospital). Analysis was then focused on those who developed a surgical site infection, as defined by either frank intra-operative purulence or positive intra-operative cultures, and subsequently underwent operative management. Results: In 27 total cases of surgical site infection, only two had a fever and four had leukocytosis at presentation. This yielded a false-negative rate for fever of 92.6% and for leukocytosis of 85.2%. In regard to infectious etiology, 22 (81.5%) cases generated positive intra-operative cultures, with Propionibacterium acnes being the most common organism isolated. Median interval to infection was 99 days from initial cranioplasty to time of infectious presentation, and average follow-up was 3.4 years. Conclusions: The utilization of fever and elevated white blood cell count in the diagnosis of post-cranioplasty infection is associated with a high false-negative rate, making the absence of these features insufficient to exclude the diagnosis of infection.

Object Over the past 15 years, vertebroplasty has emerged as a treatment for vertebral compression fractures. This technique, however, does not restore vertebral height and is associated with a high rate of cement leakage. Recently, kyphoplasty was developed in an effort to circumvent this problem. Although its immediate results have been reported, it is unclear whether the benefits endure. Methods Seventy-eight consecutive patients underwent 188 kyphoplasty procedures. The patients responded to Short Form—36 (SF-36) questionnaires, a visual analog scale (VAS) for pain rating, and the Oswestry disability index (ODI) instrument; additionally they underwent detailed neurological and radiographic examinations pre- and postoperatively. The preoperative SF-36, VAS, and ODI scores, the neurological examination results, and the radiographic data were compared with the postoperative findings. Thirteen patients died of disease progression or unrelated illness. Of the surviving patients, complete data were available in 62% (minimum follow-up period 12 months, mean 18 months). Complications included one myocardial infarction and five cases of asymptomatic cement extravasation. No case of neurological deterioration occurred during the follow-up period. Significant improvements in seven measures of the SF-36 inventory as well as on the ODI and VAS were noted early postoperatively, and these persisted throughout the follow-up period, despite a statistically insignificant decline in the measure of general health at last follow-up examination. Conclusions Kyphoplasty is an effective treatment for vertebral compression fractures. The benefits presented in the early postoperative period and persisted at 1 year posttreatment.

Spinal cord injury (SCI) removes descending input to spinal cord circuitry and results in loss of function below the level of injury. Interventions designed to increase the intrinsic capacity of CNS neurons for growth and other interventions to create a favorable environment at and below the lesion site result in increased regrowth and recovery of function. It is unlikely that any single intervention will restore function completely. After SCI in rats, transplants of fetal spinal cord tissue and the exogenous application of neurotrophic factors restore supraspinal input and permit recovery of skilled movement and locomotion. Delay of treatment leads to greater axon regeneration and recovery of function than immediate application of transplants and neurotrophic factors.

Ligamentum flavum is generally resected with impunity when a laminectomy is performed; it is a strong ligament and its removal may not be inconsequential. We sought to examine the consequence of resection of ligamentum flavum as it pertains to the formation of synovial cysts. Following IRB approval, we retrospectively reviewed the charts of consecutive patients who underwent a laminectomy for any diagnosis during the years 2009-2010. Exclusions were made for patients undergoing resection of a synovial cyst, laminectomy done as part of a fusion, and microdiscectomy. A total of 201 laminectomies were performed. 10 instances of post-laminectomy synovial cyst occurred in only the lumbar spine. Synovial cysts occurred exclusively after surgery for stenosis (n = 10). Laminectomy and resection of the ligament flavum is a risk factor for the subsequent formation of a synovial cyst. Secondary synovial cyst formation should be suspected in individuals who develop radiculopathy after laminectomy for stenosis.

Objective We investigated the mechanical and in vivo properties of a novel device, called the telescopic plate spacer (TPS), designed to promote restoration of height, alignment, and stability after cervical corpectomy for tumor. Methods The device first underwent mechanical testing. Comparisons were made with a commercially available anterior cervical plate. A caprine study was then performed. Twelve goats underwent a cervical corpectomy and placement of either a TPS filled with autograft or a plate and autograft. The animals were killed at 28 weeks and assessed for fusion. A prospective human study was then conducted. Fifteen patients with cervical or cervicothoracic tumors underwent corpectomy and placement of allograft-filled TPS. End points included pain scores and radiographic assessment of vertebral height, alignment, and stability. Results In the mechanical study, the TPS outperformed the anterior cervical plate in all modalities except for torsion stiffness and tension-bending failure load. The caprine study demonstrated fusion in six of six cases at 28 weeks in the TPS group, compared with four of six cases in the plate and autograft group. In the human study, patients (n = 15) were stabilized with the TPS after corpectomy (range, 1-3 levels; average, 1.7 levels). There were no failures of instrumentation or neurological deterioration. Stability was achieved in all patients, with an average follow-up of 9 months. Durable improvements in pain scores (P = 0.001), vertebral height (P = 0.002), and reduction of kyphosis (P = 0.046) were achieved. Conclusion The TPS can be used to restore height, alignment, and stability after corpectomy.

We present a 33-year-old man with 5-year history of low back pain who presented with an enlarging right calf. The patient underwent an extensive workup including biopsy without diagnosis. The patient's examination was significant for diminished pinprick sensation in the right L5/S1 dermatome. Reflexes were absent in the right ankle. The circumference of the right calf (58 cm) was twice that of the left. MRI revealed a herniated lumbar disc at the L5/S1 level. He then underwent a L5/S1 microdiscectomy. Following this surgery, the patient noted complete resolution of all sensory deficits in his lower extremity. His calf circumference had decreased by 5 cm at 4 months and by a total of 8 cm at his 2-year post-operative visit. Histological examination of the affected muscle demonstrated severe grouped atrophy of both type I and type II fibers. There was also evidence of compensatory fiber hypertrophy as well as fiber splitting. We concluded that the patient suffered from a herniated lumbar disc causing radiculopathy with calf hypertrophy (neurogenic hypertrophy). To our knowledge this is the first report of both grouped atrophy and compensatory hypertrophy of both muscle fiber types seen in this phenomenon.

Jugular foramen syndrome is a condition characterized by unilateral paresis of cranial nerves IX, X, and XI in the setting of extrinsic compression. Here, the authors describe the case of a giant cervical osteophyte resulting in compression of the jugular foramen. A 74-year-old man who presented with progressive dysphagia and dysarthria was found to have right-sided tongue deviation, left palatal droop, and hypophonia. His dysphagia had progressed to the point that he had lost 25 kg over a 4-month period, necessitating a gastrostomy to maintain adequate nutrition. He underwent extensive workup for his dysphagia with several normal radiographic studies. Ultimately, CT scanning and postcontrast MRI revealed a posterior osteophyte arising from the C1–2 joint space and projecting into the right jugular foramen. This resulted in a jugular foramen syndrome in addition to delayed filling of the patient's right internal jugular vein distal to the osteophyte. Although rare, a posterior cervical osteophyte should be considered in cases of jugular foramen syndrome.

Lumbar spine surgery is typically performed under general anesthesia, although spinal anesthesia can also be used. Given the prevalence of lumbar spine surgery, small differences in cost between the two anesthetic techniques have the potential to make a large impact on overall healthcare costs. We sought to perform a cost comparison analysis of spinal versus general anesthesia for lumbar spine operations. Following Institutional Review Board approval, a retrospective cohort study was performed from 2009–2012 on consecutive patients undergoing non-instrumented, elective lumbar spine surgery for spondylosis by a single surgeon. Each patient was evaluated for both types of anesthesia, with the decision for anesthetic method being made based on a combination of physical status, anatomical considerations, and ultimately a consensus agreement between patient, surgeon, and anesthesiologist. Patient demographics and clinical characteristics were compared between the two groups. Operating room costs were calculated whilst blinded to clinical outcomes and reported in percentage difference. General anesthesia (n = 319) and spinal anesthesia (n = 81) patients had significantly different median operative times of 175 ± 39.08 and 158 ± 32.75 minutes, respectively (p < 0.001, Mann–Whitney U test). Operating room costs were 10.33% higher for general anesthesia compared to spinal anesthesia (p = 0.003, Mann–Whitney U test). Complications of spinal anesthesia included excessive movement (n = 1), failed spinal attempt (n = 3), intraoperative conversion to general anesthesia (n = 2), and a high spinal level (n = 1). In conclusion, spinal anesthesia can be performed safely in patients undergoing lumbar spine surgery. It has the potential to reduce operative times, costs, and possibly, complications. Further prospective evaluation will help to validate these findings.

Objective To describe the effective treatment of a ruptured lateral sacral artery aneurysm presenting as a spinal epidural hematoma. Design Case report and literature review. Setting University teaching hospital, neurovascular center. Participant A man with a history of renal allograft who presented with sudden onset low back pain. Intervention The patient underwent emergent decompressive surgery, diagnostic angiogram and endovascular embolization. Main outcome measure Obliteration of aneurysm and restoration of neurological function. Results Surgery resulted in decompression of the cauda equina. The patient9s aneurysm was endovascularly obliterated. There was complete restoration of neurological function. Conclusion Lateral sacral artery aneurysm formation and rupture is a rare cause of epidural hemorrhage and one described only in patients who have undergone renal transplantation. It may be caused by high flow from transpelvic collaterals between both internal iliac arteries. Treatment includes endovascular obliteration and may necessitate operative decompression in the setting of neurological compromise.

Calcified lesions described within the neural axis are classified as either an ossification of the posterior longitudinal ligament, diffuse idiopathic skeletal hyperostosis, or ossification of the ligamentum flavum. We aim to describe a unique pathologic entity: the giant thoracic osteophyte. We identified four patients who were surgically treated at the Massachusetts General Hospital from 2006 to 2012 with unusual calcified lesions in the ventral aspect of the spinal canal. In order to differentiate giant thoracic osteophytes from calcified extruded disc material, disc volumetrics were performed on actual and simulated disc spaces. All patients underwent operative resection of the calcific lesion as they had signs and/or symptoms of spinal cord compression. The lesions were found to be isolated, large calcific masses that originated from the posterior aspect of adjacent thoracic vertebral bodies. Pathological examination was negative for tumor. Adjacent disc volumes were not significantly different from the index disc (p=0.91). A simulated calculation hypothesizing that the calcific mass was extruded disc material demonstrated a significant difference (p=0.01), making this scenario unlikely. In conclusion, giant thoracic osteophyte is a unique and rare entity that can be found in the thoracic spine. The central tenant of surgical treatment is resection to relieve spinal cord compression.

✓ Although the use of carotid artery stents is increasing, the management of recurrent stenosis after their placement is undefined. The authors report on a patient who underwent two left carotid endarterectomies followed by left carotid angioplasty and stent placement for recurrent stenosis. A third symptomatic recurrence was subsequently managed by placement of a saphenous vein interposition graft from the common carotid artery to the distal cervical internal carotid artery. The patient remained without hemispheric or retinal ischemia at his 5-month follow-up visit. Interposition grafting should be considered as a treatment option for carotid restenosis after initial endarterectomy and stent placement.

Dural closure with synthetic grafts has been suggested to contribute to the incidence of infection and CSF leak. The objective of this study was to assess the contribution of choice of dural closure material, as well as other factors, to the incidence of infection and CSF leak.A retrospective, consecutive cohort study of adult patients undergoing elective craniotomy was established between April 2010 and March 2011 at a single center. Exclusion criteria consisted of trauma, bur hole placement alone, and temporary CSF fluid diversion.Three hundred ninety-nine patients were included (mean follow-up 396.6 days). Nonautologous (synthetic) dural substitute was more likely to be used (n = 106) in cases of reoperation (p = 0.001). Seventeen patients developed a surgical site infection and 12 patients developed a CSF leak. Multivariate logistic regression modeling identified estimated blood loss (OR 1.002, 95% CI 1.001-1.003; p0.001) and cigarette smoking (OR 2.198, 95% CI 1.109-4.238; p = 0.019) as significant predictors of infection. Synthetic dural graft was not a predictor of infection in multivariate analysis. Infratentorial surgery (OR 4.348, 95% CI 1.234-16.722; p = 0.024) and more than 8 days of postoperative corticosteroid treatment (OR 3.886, 95% CI 1.052-16.607; p = 0.048) were significant predictors for the development of CSF leak. Synthetic dural graft was associated with a lower likelihood of CSF leak (OR 0.072, 95% CI 0.003-0.552; p = 0.036).The use of synthetic dural closure material is not associated with surgical site infection and is associated with a reduced incidence of CSF leak. Modifiable risk factors exist for craniotomy complications that warrant vigilance and further study.

Decompressive craniectomy mandates subsequent cranioplasty. Complications of cranioplasty may be independent of the initial craniectomy, or they may be contingent upon the craniectomy. Authors of this study aimed to identify surgery- and patient-specific risk factors related to the development of surgical site infection and other complications following cranioplasty.A consecutive cohort of patients of all ages and both sexes who had undergone cranioplasty following craniectomy for stroke or trauma at a single institution in the period from May 2004 to May 2012 was retrospectively established. Patients who had undergone craniectomy for infectious lesions or neoplasia were excluded. A logistic regression analysis was performed to model and predict determinants related to infection following cranioplasty.Two hundred thirty-nine patients met the study criteria. The overall rate of complication following cranioplasty was 23.85% (57 patients). Complications included, predominantly, surgical site infection, hydrocephalus, and new-onset seizures. Logistic regression analysis identified previous reoperation (OR 3.25, 95% CI 1.30-8.11, p = 0.01) and therapeutic indication for stroke (OR 2.45, 95% CI 1.11-5.39, p = 0.03) as significantly associated with the development of cranioplasty infection. Patient age, location of cranioplasty, presence of an intracranial device, bone flap preservation method, cranioplasty material, booking method, and time interval90 days between initial craniectomy and cranioplasty were not predictive of the development of cranioplasty infection.Cranioplasty complications are common. Cranioplasty infection rates are predicted by reoperation following craniectomy and therapeutic indication (stroke). These variables may be associated with patient-centered risk factors that increase cranioplasty infection risk.

It is not known whether adding fusion to lumbar decompression is necessary for all patients undergoing surgery for degenerative lumbar spondylolisthesis with symptomatic stenosis. Determining specific radiographic traits that might predict delayed instability following decompression surgery might guide clinical decision making regarding the utility of up-front fusion in patients with degenerative Grade I spondylolisthesis.Patients with Grade I degenerative lumbar spondylolisthesis (3-14 mm) with symptomatic stenosis were prospectively enrolled from a single site between May 2002 and September 2009 and treated with decompressive laminectomy without fusion. Patients with mechanical back pain or with gross motion (3 mm) on flexion-extension lumbar radiographs were excluded. The baseline radiographic variables measured included amount of slippage, disc height, facet angle, motion at spondylolisthesis (flexion-extension), and sagittal rotation angle. Data were analyzed using multivariate forward selection stepwise logistic regression, chi-square tests, Student t-test, and ANOVA.Forty patients were enrolled and treated with laminectomy without fusion, and all patients had complete radiographic data sets that were available for analysis. Reoperation was performed in 15 (37.5%) of 40 patients, with a mean follow-up duration of 3.6 years. Reoperation was performed for pain caused by instability at the index level in all 15 cases. Using multivariate stepwise logistic regression with a threshold p value of 0.35, motion at spondylolisthesis, disc height, and facet angle were predictors of reoperation following surgery. Facet angle50° was associated with a 39% rate of reoperation, disc height6.5 mm was associated with a 45% rate of reoperation, and motion at spondylolisthesis1.25 mm was associated with a 54% rate of reoperation. Patients with all 3 risk factors for instability had a 75% rate of reoperation, whereas patients with no risk factors for instability had a 0% rate of reoperation (p = 0.14).Patients with motion at spondylolisthesis1.25 mm, disc height6.5 mm, and facet angle50° are more likely to experience instability following decompression surgery for Grade I lumbar spondylolisthesis. Identification of key risk factors for instability might improve patient selection for decompression without fusion surgery.

Neurosurgical patients are at a high risk for infectious sequelae following operations. For neurosurgery in particular, the risk of surgical site infection has a unique implication given the proximity of the CSF and the CNS. Patient factors contribute to some degree; for example, cancer and trauma are often associated with impaired nutritional status, known risk factors for infection. Additionally, care-based factors for infection must also be considered, such as the length of surgery, the administration of steroids, and tissue devascularization (such as a craniotomy bone flap). When postoperative infection does occur, attention is commonly focused on potential lapses in surgical “sterility.” Evidence suggests that the surgical field is not free of microorganisms. The authors propose a paradigm shift in the nomenclature of the surgical field from “sterile” to “clean.” Continued efforts aimed at optimizing immune capacity and host defenses to combat potential infection are warranted.

BACKGROUND: Increasingly studies have identified socioeconomic factors adversely affecting healthcare outcomes for a multitude of diseases. To date, however, there has not been a study correlating socioeconomic details from nationwide databases on the prevalence of advanced coronary artery disease. We seek to identify whether socioeconomic factors contribute to advanced coronary artery disease prevalence in the United States. METHODS AND FINDINGS: State specific prevalence data was queried form the United States Nationwide Inpatient Sample for 2009. Patients undergoing percutaneous coronary angioplasty and coronary artery bypass graft were identified as principal procedures. Non-cardiac related procedures, lung lobectomy and hip replacement (partial and total) were identified and used as control groups. Information regarding prevalence was then merged with data from the Behavioral Risk Factor Surveillance System, the largest, on-going telephone health survey system tracking health conditions and risk behaviors in the United States. Pearson's correlation coefficient was calculated for individual socioeconomic variables including employment status, level of education, and household income. Household income and education level were inversely correlated with the prevalence of percutaneous coronary angioplasty (-0.717; -0.787) and coronary artery bypass graft surgery (-0.541; -0.618). This phenomenon was not seen in the non-cardiac procedure control groups. In multiple linear regression analysis, socioeconomic factors were significant predictors of coronary artery bypass graft and percutaneous transluminal coronary angioplasty (p