Incidence and management of postoperative pseudomeningocele and cerebrospinal fluid leak after Chiari malformation type I decompression.

OBJECTIVE: The optimal surgical management of Chiari malformation type I (CM-I) remains controversial and heterogeneous. The authors sought to investigate patient-specific, technical, and perioperative features that may affect the incidence of CSF-related complications including pseudomeningocele and CSF leak at their institution. METHODS: The authors performed a single-center, retrospective review of all adult patients with CM-I who underwent posterior fossa decompression. Patient demographics, operative details, and perioperative factors were collected via electronic medical record review. The authors performed Fisher's exact test and independent Student t-tests for categorical and continuous variables, respectively. Univariate regression analysis was performed to determine odds ratios. A multivariable regression analysis was performed for those factors with p < 0.10 or large effect sizes (OR ≥ 2.0 or ≤ 0.50) by univariate analysis. The STROBE guidelines for observational studies were followed. RESULTS: A total of 59 adult patients were included. Most patients were female (78.0%), and the mean body mass index was 32.2 (± 9.0). Almost one-third (30.5%) of patients had a syrinx on preoperative imaging. All patients underwent expansile duraplasty, of which 47 (79.7%) were from autologous pericranium. Arachnoid opening for fourth ventricular inspection was performed in 26 (44.1%) cases. CSF-related complications were identified in 18 (30.5%) of cases. Thirteen (22.0%) patients required readmission and 11 (18.6%) required intervention such as wound revision (n = 5), wound revision with CSF diversion (n = 4), CSF diversion alone (n = 1), or blood patch (n = 1). Three (5.1%) patients required permanent CSF diversion. Male sex (OR 3.495), diabetes mellitus (OR 0.249), tobacco use (OR 2.53), body mass index more than 30 (OR 2.45), preoperative syrinx (OR 1.733), autologous duraplasty (OR 0.331), and postoperative steroids (OR 2.825) were included in the multivariable analysis. No factors achieved significance by univariate or multivariable analysis (all p > 0.05). CONCLUSIONS: The authors report a single-center, retrospective experience of posterior fossa decompression for 59 adults with CM-I. No perioperative or technical features were found to affect the CSF-related complication rate. More standardized practices within centers are necessary to better delineate the true risk factors and potential protective factors against CSF-related complications.

Postoperative Cerebrospinal Fluid-Related Complications After Posterior Fossa and Posterolateral Skull Base Surgeries: Development of a Predictive Model and Clinical Risk Score.

BACKGROUND: Postoperative pseudomeningocele (PMC) and cerebrospinal fluid (CSF) leak are common complications following posterior fossa and posterolateral skull base surgeries. We sought to 1) determine the rate of CSF-related complications and 2) develop a perioperative model and risk score to identify the highest risk patients for these events. METHODS: We performed a retrospective cohort of 450 patients undergoing posterior fossa and posterolateral skull base procedures from 2016 to 2020. Logistic regressions were performed for predictor selection for 3 prespecified models: 1) a priori variables, 2) predictors selected by large effect sizes, and 3) predictors with P ≤ 0.100 on univariable analysis. A final model was created by elimination of nonsignificant predictors, and the integer-based postoperative CSF-related complications (POCC) clinical risk score was derived. Internal validation was done using 10-fold cross-validation and bootstrapping with uniform shrinkage. RESULTS: A total of 115 patients (25.6%) developed PMC and/or CSF leakage. Age >55 years (odds ratio [OR], 0.560; 95% confidence interval [CI], 0.328-0.954), body mass index >30 kg/m2 (OR, 1.88; 95% CI, 1.14-3.10), and postoperative CSF diversion (OR, 2.85; 95% CI, 1.64-5.00) were associated with CSF leak and PMC. Model 2 was the most predictive (cross-validated area under the receiver operating characteristic curve, 0.690). The final risk score was devised using age, body mass index class, dural repair technique, use of bone substitute, and duration of postoperative CSF diversion. The POCC score performed well (cross-validated area under the receiver operating characteristic curve, 0.761) and was highly specific (96.1%). CONCLUSIONS: We created the first generalizable and predictive risk score to identify patients at risk of CSF-related complications. The POCC score could improve surveillance, inform doctor-patient discussions regarding the risks of surgery, and assist in perioperative management.

Koos Classification of Vestibular Schwannomas: A Reliability Study.

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

Sequential Coiling-Assisted Deployment of Flow Diverter for Treatment of Fusiform Middle Cerebral Artery Aneurysms.

BACKGROUND AND IMPORTANCE: Fusiform intracranial aneurysms remain challenging lesions to treat. These aneurysms have historically required bypass procedures or clip remodeling constructs for cure. Recently, endovascular specialists have reported experience with flow diversion for complex fusiform aneurysms of the vertebrobasilar system, with mixed results. Vascular anatomy for anterior circulation fusiform aneurysms may make these lesions more amenable to flow diversion and embolization procedures; however, published experience with these techniques is lacking. In this report, we describe a sequential coiling-assisted deployment of flow diverter for the treatment of fusiform middle cerebral artery (MCA-M1) aneurysms in 2 cases, 1 presenting acutely with subarachnoid hemorrhage and another with progressive aneurysm enlargement. CLINICAL PRESENTATION: Two patients, a 36-yr-old male presenting with subarachnoid hemorrhage and a 60-yr-old female presenting with aneurysm enlargement were treated for fusiform aneurysms of the M1 segment of the MCA using a sequential, partial deployment of coils and flow diverter through 2 microcatheters to facilitate mutual mechanical support for both coil and flow diverter (Pipeline Embolization Device; Medtronic Inc, Dublin, Ireland). Both patients achieved favorable outcomes and follow-up angiography demonstrated complete vessel reconstruction in both cases. CONCLUSION: The treatment of complex, fusiform, large vessel aneurysms remains challenging. As experience with new endovascular technologies and techniques grows, these lesions may be treated safely with interventional methods. The technique of partial flow diverter deployment and stabilization with coils with sequential delivery of both devices using dual microcatheter was both safe and effective.

Combined Outcomes of Endovascular or Surgical Treatment of Unruptured Anterior Communicating Artery Aneurysms: Is a More Aggressive Management Strategy Warranted?

BACKGROUND: Updated natural history studies that suggest anterior communicating artery aneurysms have a higher risk of rupture than formerly appreciated. As endovascular and open techniques advance, morbidity may fall to levels that suggest the feasibility of intervention even for small aneurysms. This study was conducted to assess the risk associated with treating smaller, unruptured anterior communicating artery aneurysms. METHODS: A cross-sectional study of 149 patients with unruptured anterior communicating aneurysms treated over a 6-year period was performed. Treatment was based on an estimate of the highest efficacy/lowest risk for each patient. Outcomes were recorded at 3 months and 1 year after treatment. The primary outcome measure was a modified Rankin scale score of >2 at 1 year, or persistent cognitive impairment confirmed by a neurologist. RESULTS: The average patient age was 61 years (range, 34-84 years), and the median aneurysm size was 5.5 mm (interquartile range, 4-7 mm). Clipping was performed in 98 patients (65.8%). Poor outcome was observed in 12 patients (8%). Neither aneurysm size nor treatment method was predictive of poor outcome. Both a history of coronary artery disease/myocardial infarction and age were most significantly associated with poor outcome (coronary artery disease/myocardial infarction: odds ratio [OR], 8.11; 95% confidence interval [CI], 2.20-29.86; P = 0.002; age: OR, 1.09; 95% CI, 1.019-1.17; P = 0.013). Dichotomized for age >65 years, the odds of poor outcome increased nearly 11-fold (OR, 10.93; 95% CI, 2.29-52.03; P = 0.003). CONCLUSIONS: The risk associated with treating unruptured anterior communicating artery aneurysms in patients age <65 years is low. Comparing risk with natural history studies, these patients can be expected to outperform natural history within 5 years. Recognizing the risk of smaller anterior communicating artery aneurysms, these findings suggest that treatment of even small lesions may be beneficial.

Antiplatelet Medication Reversal Strategies in Operative Intracranial Hemorrhage: A Survey of Practicing Neurosurgeons.

BACKGROUND: Antiplatelet therapy is common and complicates operative management of acute intracranial hemorrhage. Few data exist to guide antiplatelet reversal strategies. METHODS: An online survey detailing antiplatelet reversal strategies in patients presenting with acute operative intracranial hemorrhage (subdural hematoma, epidural hematoma, and intracerebral hemorrhage) was distributed to board-certified neurosurgeons in North America. RESULTS: From 2782 functional e-mail addresses, there were 493 (17.7%) responses to question 1 and 429 (15.4%) completed surveys. Most respondents chose to perform no additional laboratory testing before surgical intervention, regardless of hemorrhage type. The most common antiplatelet reversal strategy in the presence of aspirin was platelet transfusion (subdural hematoma and intracerebral hemorrhage) or no intervention (epidural hematoma). The most common antiplatelet reversal strategy in the presence of an adenosine diphosphate antagonist or dual antiplatelet therapy was platelet transfusion or platelet transfusion with desmopressin acetate administration. There was a statistically significant difference in management strategy depending on the antiplatelet therapy (P < 0.001). CONCLUSIONS: When patients on antiplatelet medication present with operative intracranial hemorrhage, the majority of neurosurgeons do not perform qualitative platelet testing. Antiplatelet reversal strategies are significantly influenced by the antiplatelet therapy with more aggressive reversal strategies employed in the presence of ADP antagonists.

Whole blood aggregometry prior to Pipeline embolization device treatment of intracranial aneurysms: defining an optimal platelet inhibition cutoff value for clopidogrel.

OBJECTIVEDual antiplatelet therapy is required for the treatment of intracranial aneurysms with the Pipeline embolization device (PED). Platelet function testing (PFT) is often used to assess the efficacy of the antiplatelet regimen prior to PED placement. The optimal impedance values for whole blood aggregometry in this setting have not been defined.METHODSA retrospective review of a prospectively maintained database was performed for the years 2011-2015 to identify patients with intracranial aneurysms treated with the PED who underwent pretreatment PFT using whole blood aggregometry. Antiplatelet therapy was not altered based on PFT results; all patients remained on standard doses of aspirin and clopidogrel. Clinical, radiographic, and laboratory data were analyzed to identify the optimal cutoff impedance value for clopidogrel responsiveness using the receiver operating characteristic curve and Youden's index.RESULTSForty-nine patients underwent 53 endovascular procedures for the treatment of 76 aneurysms using the PED. The majority of these aneurysms were located in the anterior circulation (90.8%) and affected the internal carotid artery (89.5%). Patients in 30 procedures (56.6%) were identified as clopidogrel responders based on the manufacturer cutoff value (< 6 Ω). Thromboembolic complications occurred in 13 (24.5%) procedures; patients in 6 (11.3%) cases were symptomatic and those in 3 (5.7%) cases had ischemic strokes. Eleven of the 13 (84.6%) thromboembolic complications occurred in clopidogrel nonresponders. An impedance value of ≥ 6 Ω was independently associated with thromboembolic complications. The optimal electrical impedance value was identified as ≥ 6 Ω (sensitivity 84.6%, specificity 70.0%, area under the curve 0.77) for identifying clopidogrel nonresponders.CONCLUSIONSThromboembolic complications are more common following PED placement in patients who do not respond adequately to clopidogrel. Clopidogrel nonresponders can be identified using pretreatment whole blood aggregometry. The optimal cutoff value to categorize a patient as a clopidogrel nonresponder when using whole blood aggregometry is ≥ 6 Ω.

Relationship between external ventricular drain clamp trials and ventriculoperitoneal shunt insertion following nontraumatic subarachnoid hemorrhage: a single-center study.

OBJECTIVE: Currently, there is no established standard regarding the ideal number of external ventricular drain (EVD) clamp trials performed before ventriculoperitoneal (VP) shunt insertion following nontraumatic subarachnoid hemorrhage (SAH). In this study, the authors aimed to evaluate this relationship. METHODS: A retrospective review of all patients presenting with SAH between July 2007 and December 2016 was performed. Patients with SAH who had received an EVD within the first 24 hours of hospital admission and had undergone at least 1 clamp trial prior to EVD removal were eligible for inclusion in the study. Patient demographics, clinical presentations, SAH etiologies and grades, clamp trial data, hospital lengths of stay, and functional outcomes were recorded. RESULTS: One hundred fourteen patients with nontraumatic SAH complicated by posthemorrhagic hydrocephalus were included in the study. The median patient age was 57 years (range 28-90 years), with a male/female ratio of 1:1.7. A ruptured aneurysm was the underlying etiology of SAH in 79.8% of patients. A majority of patients (69.4%) had a Hunt and Hess grade III-V on admission. The median number of clamp trials performed was 2 (range 1-6). A VP shunt was required in 40.4% of patients. In those who underwent 2 and 3 clamp trials, 60% and 38.9%, respectively, did not require subsequent VP shunt placement. CONCLUSIONS: Surgical placement of a VP shunt is associated with complications. Clamp trials are routinely performed before making the decision to insert a shunt. In the present study, the authors found that a significant percentage of patients passed their second and third clamp trials without requiring subsequent shunt insertion. These data support performing multiple clamp trials prior to shunt placement.

Proposal of a follow-up imaging strategy following Pipeline flow diversion treatment of intracranial aneurysms.

OBJECTIVE: There is currently no standardized follow-up imaging strategy for intracranial aneurysms treated with the Pipeline embolization device (PED). Here, the authors use follow-up imaging data for aneurysms treated with the PED to propose a standardizable follow-up imaging strategy. METHODS: A retrospective review of all patients who underwent treatment for ruptured or unruptured intracranial aneurysms with the PED between March 2013 and March 2017 at 2 major academic institutions in the US was performed. RESULTS: A total of 218 patients underwent treatment for 259 aneurysms with the PED and had undergone at least 1 follow-up imaging session to assess aneurysm occlusion status. There were 235 (90.7%) anterior and 24 posterior (9.3%) circulation aneurysms. On Kaplan-Meier analysis, the cumulative incidences of aneurysm occlusion at 6, 12, 18, and 24 months were 38.2%, 77.8%, 84.2%, and 85.1%, respectively. No differences in the cumulative incidence of aneurysm occlusion according to aneurysm location (p = 0.39) or aneurysm size (p = 0.81) were observed. A trend toward a decreased cumulative incidence of aneurysm occlusion in patients 70 years or older was observed (p = 0.088). No instances of aneurysm rupture after PED treatment or aneurysm recurrence after occlusion were noted. Sixteen (6.2%) aneurysms were re-treated with the PED; 11 of these had imaging follow-up data available, demonstrating occlusion in 3 (27.3%). CONCLUSIONS: The authors propose a follow-up imaging strategy that incorporates 12-month digital subtraction angiography and 24-month MRA for patients younger than 70 years and single-session digital subtraction angiography at 12 months in patients 70 years or older. For recurrent or persistent aneurysms, re-treatment with the PED or use of an alternative treatment modality may be considered.

Recrudescence of Symptoms of Remote Ischemic Stroke After a Cerebral Angiogram.

BACKGROUND: Ischemic stroke recrudescence, or reappearance of previously resolved symptoms of ischemic stroke, may occur after physiologic stress. Although generally thought to be uncommon, this syndrome may account for a significant proportion of stroke mimics. CASE DESCRIPTION: A 67-year-old man was admitted with a Hunt and Hess grade 2 spontaneous subarachnoid hemorrhage. He underwent digital subtraction cerebral angiography as part of imaging evaluation. About 30 minutes after the procedure, he developed dysarthria, right facial droop, and right pronator drift. The patient and family denied a history of similar symptoms or previous ischemic stroke. Brain magnetic resonance imaging demonstrated a remote left lacunar infarction. The symptoms resolved after 24 hours and were attributed to recrudescence of the patient's previous lacunar infarction. The physiological stress of the subarachnoid hemorrhage combined with the cerebral angiogram likely triggered the event. CONCLUSIONS: Recrudescence of symptoms of a previous stroke may be initiated by subarachnoid hemorrhage and/or a cerebral angiogram. The possibility of ischemic stroke recrudescence should be kept in mind as a possible stroke mimic.

Ruptured Distal Anterior Choroidal Artery Aneurysm Treated with Superselective Provocative Testing and Coil Embolization.

BACKGROUND AND IMPORTANCE: Aneurysms of the anterior choroidal artery are uncommon, and distal anterior choroidal artery aneurysms are even rarer, with only 34 cases reported in the medical literature. These lesions have been most commonly reported in association with moyamoya disease or arteriovenous malformations. Most published experience with these aneurysms involves open surgical approaches. Reports of endovascular treatment have been in patients with lesions distal to the plexal point and have employed vessel occlusion with liquid embolic agents in preference to coil embolization. CLINICAL PRESENTATION: We present a case of a ruptured distal anterior choroidal artery aneurysm located on the cisternal segment of the artery. This lesion was successfully treated with endovascular coil embolization. Additionally, the patient underwent pre-embolization superselective provocative testing with amobarbital to assess the safety of parent vessel occlusion. CONCLUSION: Endovascular coil embolization for distal anterior choroidal artery aneurysms is technically feasible and may be preferable to embolization with liquid embolic agents for lesions proximal to the plexal point. This case illustrates the utility of provocative testing and efficacy of endovascular coil embolization for lesions in this unique location.

Reliability assessment of the Biffl Scale for blunt traumatic cerebrovascular injury as detected on computer tomography angiography.

OBJECTIVE Blunt traumatic cerebrovascular injury (TCVI) represents structural injury to a vessel due to high-energy trauma. The Biffl Scale is a widely accepted grading scheme for these injuries that was developed using digital subtraction angiography. In recent years, screening CT angiography (CTA) has been used to identify patients with TCVI. The reliability of this scale, with injuries assessed using CTA, has not yet been determined. METHODS Seven independent raters, including 2 neurosurgeons, 2 neuroradiologists, 2 neurosurgical residents, and 1 neurosurgical vascular fellow, independently reviewed each presenting CTA of the neck performed in 40 patients with confirmed TCVI and assigned a Biffl grade. Ten images were repeated to assess intrarater reliability, for a total of 50 CTAs. Fleiss' multirater kappa (κ) and interclass correlation were calculated as a measure of interrater reliability. Weighted Cohen's κ was used to assess intrarater reliability. RESULTS Fleiss' multirater κ was 0.65 (95% CI 0.61-0.69), indicating substantial agreement as to the Biffl grade assignment among the 7 raters. Interclass correlation was 0.82, demonstrating excellent agreement among the raters. Intrarater reliability was perfect (weighted Cohen's κ = 1) in 2 raters, and near perfect (weighted Cohen's κ > 0.8) in the remaining 5 raters. CONCLUSIONS Grading of TCVI with CTA using the Biffl Scale is reliable.

External ventricular drain placement in the intensive care unit versus operating room: evaluation of complications and accuracy.

OBJECTIVE: External ventricular drain (EVD) placement is a common neurosurgical procedure performed in both the intensive care unit (ICU) and operating room (OR). The optimal setting for EVD placement in regard to safety and accuracy of placement is poorly defined. METHODS: A retrospective chart review was performed on 150 consecutive patients who underwent EVD placement at a tertiary care center from January of 2013 to February of 2014. Clinical and radiographic data were obtained and used to compare safety and accuracy of placement between EVDs placed in the ICU versus OR. RESULTS: One hundred and thirty eight patients were evaluated. Complications (hemorrhage, infection, non-functional drain) occurred in 21.5% of ICU placements and 6.7% of OR placements (p = 0.028). Grade 1, 2, and 3 placements occurred in 67.7%, 25.8%, and 6.5% of ICU placements, respectively, versus 55.6%, 42.2%, and 2.2% of OR placements (p = 0.258). No patient who received pre-placement antibiotics suffered a ventriculostomy associated infection (VAI). CONCLUSION: Patients who underwent ventriculostomy placement in the ICU differed in important ways (i.e. indication for placement and the administration of pre-procedure prophylactic antibiotics) from patients treated in the OR. However, the available data suggests that complications of hemorrhage, infection, and non-functional drains may be mitigated by ventriculostomy placement in the OR.

Chemoprophylaxis for venous thromboembolism in traumatic brain injury: a review and evidence-based protocol.

Venous thromboembolism (VTE) is a recognized source of morbidity and mortality in patients suffering traumatic brain injury (TBI). While traumatic brain injury is a recognized risk factor for the development of VTE, its presence complicates the decision to begin anticoagulation due to fear of exacerbating the intracranial hemorrhagic injury. The role of chemoprophylaxis in this setting is poorly defined, leading to a wide variability in clinical practice. A comprehensive review of the literature was performed in an effort to summarize relevant data and construct a chemoprophylaxis protocol to be implemented in a Level I Trauma Center. The review reveals robust evidence regarding the safety and efficacy of chemoprophylaxis in the setting of TBI following demonstration of a stable intracranial injury. In light of this data, a protocol is assembled that, in the absence of predetermined exclusion criteria, will initiate chemoprophylaxis within 24h after the demonstration of a stable intracranial injury by computed tomography (CT).

Treatment resistance mechanisms of malignant glioma tumor stem cells.

Malignant gliomas are highly lethal because of their resistance to conventional treatments. Recent evidence suggests that a minor subpopulation of cells with stem cell properties reside within these tumors. These tumor stem cells are more resistant to radiation and chemotherapies than their counterpart differentiated tumor cells and may underlie the persistence and recurrence of tumors following treatment. The various mechanisms by which tumor stem cells avoid or repair the damaging effects of cancer therapies are discussed.