A Novel Scoring System Predicting Aneurysm Incomplete Occlusion after Flow Diversion: A 10-year experience.

BACKGROUND: Factors impacting the rate of aneurysm occlusion after FD have been well described in the literature. In this paper, we sought to evaluate those variables to develop and validate a scoring system predicting aneurysm incomplete occlusion after FD. METHODS: Retrospective review of patients with intracranial aneurysms treated with FD at a single institution between March 2013 and March 2023. Multivariable logistic regression model was developed using factors associated with aneurysm incomplete occlusion. The ABC scoring system consisted of: Age (< 60 years old: 0, 60-69 years: 1, 70-79: 2, and ≥80: 3), Branch coming out of the aneurysm dome/neck (yes: 2, no:0), and Cigarette smoking history (never-smoker:1, current or past smoker: 0). The scoring system performance was evaluated with receiver operating characteristic curve and calculating the area under the curve (AUC). RESULTS: A total of 449 patients with 563 aneurysms treated in 482 procedures were evaluated. Most cases were females (81.7%) with a median age of 59 years-old. At a median follow-up of 13.2 months, 84.0% of aneurysms were completely or near-complete occluded. The scoring system had an AUC of 0.71. A value ≥2, reached a sensitivity of 74.4%, specificity of 60.9%, an LR+ of 1.90, and proved to be reliable in predicting the risk of incomplete occlusion (OR=4.53; 95% confidence interval, 2.73-7.54; P < 0.001). CONCLUSION: The proposed ABC scoring system can be used to evaluate the risk of aneurysm incomplete occlusion after treatment with FD, identifying patients who would benefit from adjunctive coiling or alternate treatment modalities.

Superficial Temporal Artery Size Changes After Encephaloduroarteriosynangiosis (EDAS) for the Treatment of Moyamoya Disease.

BACKGROUND AND OBJECTIVES: Surgery is the mainstay of stroke prevention in patients with symptomatic Moyamoya disease. We present the results of a single-center retrospective study of indirect revascularization surgery for adult moyamoya disease, emphasizing angiographic outcomes, including dilation of the superficial temporal artery and formation of new collaterals. METHODS: A prospectively maintained database of procedures performed for Moyamoya disease was reviewed. Adult patients treated with indirect revascularization and with long-term angiographic follow-up were included. Pre-operative and postoperative angiographic images and baseline and procedural characteristics were analyzed. A Wilcoxon signed-rank test was used to test the hypothesis that the superficial temporal artery increases in diameter postoperatively. RESULTS: We identified 40 hemispheres in 27 patients, of which 35 had a sufficient angiographic follow-up. Bilateral procedures were performed on 16 patients. Most patients were female (72.5%), with a median age of 43 years-old. The most common clinical presentation was ischemic stroke in 59.3% of cases. All patients underwent an encephaloduroarteriosynangiosis (EDAS) for treatment. A follow-up angiogram was performed at a median of 13.8 months postoperatively, showing STA-derived collaterals in 71.4% and collateral ingrowth via the burr holes in 61.8% of cases. Disease progression was evident in 34.3% of hemispheres. The normalized STA diameter was significantly increased postoperatively (2.4 to 3 mm; p<0.05). A univariate analysis revealed that transdural collaterals and hyperlipidemia may affect collateral ingrowth from the STA, and no other patient or procedure-related factors, including replacement of the bone flap, impacted on this. CONCLUSION: A significant increase in STA diameter on follow-up angiography after EDAS was found, however this was not directly associated with STA collateral development. Rates of postoperative transient ischemic attacks were low, and no patients had a new ischemic or hemorrhagic stroke at last follow up. The presence of transdural collaterals and the absence of hyperlipidemia were associated with STA collateral development on follow-up angiography, but the causality of this finding is unclear.

Factors Associated with Extended Hospitalization in Patients Who Had Adjuvant Middle Meningeal Artery Embolization After Conventional Surgery for Chronic Subdural Hematomas.

BACKGROUND: This study aims to evaluate the length of stay (LOS) in patients who had adjunct middle meningeal artery embolization (MMAE) for chronic subdural hematoma after conventional surgery and determine the factors influencing the LOS in this population. METHODS: A retrospective review of 107 cases with MMAE after conventional surgery between September 2018 and January 2024 was performed. Factors associated with prolonged LOS were identified through univariable and multivariable analyses. RESULTS: The median LOS for MMAE after conventional surgery was 9 days (interquartile range = 6-17), with a 3-day interval between procedures (interquartile range = 2-5). Among 107 patients, 58 stayed ≤ 9 days, while 49 stayed longer. Univariable analysis showed the interval between procedures, type of surgery, MMAE sedation, and the number of complications associated with prolonged LOS. Multivariable analysis confirmed longer intervals between procedures (odds ratio [OR] = 1.52; P < 0.01), ≥2 medical complications (OR = 13.34; P = 0.01), and neurological complications (OR = 5.28; P = 0.05) were independent factors for lengthier hospitalizations. There was a trending association between general anesthesia during MMAE and prolonged LOS (P = 0.07). Subgroup analysis revealed diabetes (OR = 5.25; P = 0.01) and ≥2 medical complications (OR = 5.21; P = 0.03) correlated with a LOS over 20 days, the 75th percentile in our cohort. CONCLUSIONS: The interval between procedures and the number of medical and neurological complications were strongly associated with prolonged LOS in patients who had adjunct MMAE after open surgery. Reducing the interval between the procedures and potentially performing both under 1 anesthetic may decrease the burden on patients and shorten their hospitalizations.

Defining light transmission aggregometry cutoff values for clopidogrel and aspirin resistance in flow diversion treatment of intracranial aneurysms.

OBJECTIVE: Concern about thromboembolic events after flow diversion (FD) warrants dual antiplatelet therapy for 3 to 6 months. Platelet function tests are routinely performed prior to the procedure to detect clopidogrel responsiveness, as resistance is associated with CYP2C19 gene polymorphisms. This study aimed to identify optimal cutoff values in light transmission aggregometry (LTA) for clopidogrel and aspirin as predictive indicators of thromboembolic complications. METHODS: The authors conducted a retrospective analysis of aneurysms treated with FD between 2013 and 2023 at a single academic institution. Patients with LTA data for adenosine diphosphate (ADP) and arachidonic acid (ARA) were included, excluding those with aborted procedures. Receiver operating characteristic curves were plotted for ADP and ARA assays to determine optimal cutoff values. RESULTS: A total of 442 patients harboring 552 aneurysms treated in 485 procedures were selected for this analysis. Complete and near-complete aneurysm occlusion on the last radiological follow-up was achieved in 81.8% of aneurysms in a median last imaging follow-up of 13.9 months. A good functional outcome (modified Rankin Scale score ≤ 2) was achieved in 96.3% of patients on the last follow-up. Thromboembolic complications occurred in 4.9% of procedures, and intracranial hemorrhagic complications in 1.9%. For the ADP assay, a value ≥ 40% reached a sensitivity of 82.1% and a specificity of 42.9% with a positive likelihood ratio (LR) of 1.50. For the ARA assay, a value ≥ 13.5% reached a sensitivity of 82.1% and a specificity of 45.6% with a positive LR of 1.51. CONCLUSIONS: This study analyzed the largest FD-treated cohort in which optimal LTA platelet function thresholds for clopidogrel were evaluated and is the first to assess LTA values for aspirin. The authors found that values ≥ 40% for clopidogrel and ≥ 13.5% for aspirin were optimal for predicting thromboembolic complications after FD in treating aneurysms.

Educational Limitations of ChatGPT in Neurosurgery Board Preparation.

Objective This study evaluated the potential of Chat Generative Pre-trained Transformer (ChatGPT) as an educational tool for neurosurgery residents preparing for the American Board of Neurological Surgery (ABNS) primary examination. Methods Non-imaging questions from the Congress of Neurological Surgeons (CNS) Self-Assessment in Neurological Surgery (SANS) online question bank were input into ChatGPT. Accuracy was evaluated and compared to human performance across subcategories. To quantify ChatGPT's educational potential, the concordance and insight of explanations were assessed by multiple neurosurgical faculty. Associations among these metrics as well as question length were evaluated. Results ChatGPT had an accuracy of 50.4% (1,068/2,120), with the highest and lowest accuracies in the pharmacology (81.2%, 13/16) and vascular (32.9%, 91/277) subcategories, respectively. ChatGPT performed worse than humans overall, as well as in the functional, other, peripheral, radiology, spine, trauma, tumor, and vascular subcategories. There were no subjects in which ChatGPT performed better than humans and its accuracy was below that required to pass the exam. The mean concordance was 93.4% (198/212) and the mean insight score was 2.7. Accuracy was negatively associated with question length (R2=0.29, p=0.03) but positively associated with both concordance (p<0.001, q<0.001) and insight (p<0.001, q<0.001). Conclusions The current study provides the largest and most comprehensive assessment of the accuracy and explanatory quality of ChatGPT in answering ABNS primary exam questions. The findings demonstrate shortcomings regarding ChatGPT's ability to pass, let alone teach, the neurosurgical boards.

Comparison of Thromboembolic Events Between Pipeline Embolization Device (PED) Shield and PED/PED Flex: A Propensity Score-Matched Analysis.

BACKGROUND AND OBJECTIVES: The pipeline embolization device (PED) Flex with Shield technology is a third-generation flow diverter used for intracranial aneurysm treatment designed to decrease thrombogenicity through a phosphorylcholine coating. Herein, we aim to compare the rate of thromboembolic events in PED with Shield technology and PED without it through propensity score matching. METHODS: We conducted a retrospective analysis of aneurysms treated with PED first-generation/PED Flex and PED with Shield between 2013 and 2023 at a single academic institution. Patients were matched through propensity score by controlling for confounding factors including age, smoking history, diabetes, previous subarachnoid hemorrhage, modified Rankin Scale pretreatment, location, aneurysm size, previous treatment, and clopidogrel or aspirin resistance. After matching, we evaluated for periprocedural and postoperative thromboembolic events. Data analysis was performed using Stata 14. RESULTS: A total of 543 patients with 707 aneurysms treated in 605 procedures were included in the analysis. From these, 156 aneurysms were treated with PED with Shield (22.07%) and 551 (77.93%) without Shield technology. Propensity score matching resulted in 84 matched pairs. The rate of thromboembolic events was 3.57% for PED Shield and 10.71% for PED first-generation/PED Flex ( P = .07), while retreatment rates were 2.38% for PED Shield and 8.32% for PED Flex ( P = .09). Complete occlusion at first ( P = .41) and last imaging follow-up ( P = .71), in-stent stenosis ( P = .95), hemorrhagic complications ( P = .31), and functional outcomes ( P = .66) were comparable for both groups. CONCLUSION: This is the first study in the literature performing a propensity scored-matched analysis comparing PED with PED with Shield technology. Our study suggests a trend toward lower thromboembolic events for PED Shield, even after controlling for aspirin and clopidogrel resistance, and a trend toward lower aneurysm retreatment rates with PED Shield, without reaching statistical significance.

Effect of Statin on Radiographic and Clinical Outcomes of Intracranial Aneurysms Treated With Pipeline Embolization: A Propensity Score-Matched Analysis.

BACKGROUND AND OBJECTIVES: Studies have shown that use of statin can improve radiographic and clinical outcomes in patients receiving treatment for coronary artery or peripheral vascular stenosis. Statins are thought to be effective by reducing arterial wall inflammation. The same mechanism may have an influence on the efficacy of pipeline embolization device (PED) for intracranial aneurysm treatment. Although this question has been of interest, there is a lack of well-controlled data in the literature. The objective of this study is to analyze the effect of statins on outcomes of aneurysms treated with pipeline embolization through propensity score matching. METHODS: Patients who underwent PED for unruptured intracranial aneurysms at our institution between 2013 and 2020 were identified. Patients on statin treatment vs those who were not were matched through propensity score by controlling for confounding factors including age, sex, current smoking status, diabetes, aneurysm morphology, volume, neck size, location of aneurysm, history of treatment for the same aneurysm, type of antiplatelet therapy, and elapsed time at last follow-up. Occlusion status at first follow up and last follow-up, and incidence of in-stent stenosis and ischemic complications during the follow-up period were extracted for comparison. RESULTS: In total, 492 patients with PED were identified, of whom 146 were on statin therapy and 346 were not. After one-to-one nearest neighbor matching, 49 cases in each group were compared. At last follow-up, 79.6%, 10.2%, and 10.2% of cases in the statin therapy group and 67.4%, 16.3%, and 16.3% in the nonstatin group were noted to have Raymond-Roy 1, 2, and 3 occlusions, respectively ( P = .45). No significant difference was observed in immediate procedural thrombosis ( P > .99), long-term in-stent stenosis ( P > .99), ischemic stroke ( P = .62), or retreatment ( P = .49). CONCLUSION: Statin use does not affect occlusion rate or clinical outcomes in patients treated with PED treatment for unruptured intracranial aneurysms.

Reduced recurrence of chronic subdural hematomas treated with open surgery followed by middle meningeal artery embolization compared to open surgery alone: a propensity score-matched analysis.

OBJECTIVE: Middle meningeal artery embolization (MMAE) is an emerging endovascular treatment technique with proven promising results for chronic subdural hematomas (cSDHs). MMAE as an adjunct to open surgery is being utilized with the goal of preventing the recurrence of cSDH. However, the efficacy of MMAE following surgical evacuation of cSDH has not been clearly demonstrated. The authors sought to compare the outcomes of open surgery followed by MMAE versus open surgery alone. METHODS: Patients who underwent surgical evacuation alone (open surgery-alone group) or MMAE along with open surgery for cSDH (adjunctive MMAE group) were identified at the authors' institution. Two balanced groups were obtained through propensity score matching. Primary outcomes included recurrence risk and reintervention rate. Secondary outcomes included decrease in hematoma size and modified Rankin Scale (mRS) score at last follow-up. Variables in the two groups were compared by use of the Mann-Whitney U-test, paired-sample t-test, and Fisher's exact test. RESULTS: A total of 345 cases of open surgery alone and 52 cases of open surgery with adjunctive MMAE were identified. After control for subjective confounders, 146 patients treated with open surgery alone and 41 with adjunctive MMAE following open surgery with drain placement were included in the analysis. Before matching, the rebleeding risk and reintervention rate for open surgery trended higher in the open surgery alone than the open surgery plus MMAE group (14.4% vs 7.3%, p = 0.18; and 11.6% vs 4.9%, p = 0.17, respectively). No significant differences were seen in duration of radiographic or clinical follow-ups or decreases in hematoma size and mRS score at last follow-up. After one-to-one nearest neighbor propensity score matching, 26 pairs of cases were compared for outcomes. Rates of recurrence (7.7% vs 30.8%, p = 0.038) and overall reintervention (3.8% vs 23.1%, p = 0.049) after open surgery were found to be significantly lower in the adjunctive MMAE group than the open surgery-alone group. With one-to-many propensity score matching, 76 versus 37 cases were compared for open surgery alone versus adjunctive MMAE following open surgery. Similarly, the adjunctive MMAE group had significantly lower rates of recurrence (5.4% vs 19.7%, p = 0.037) and overall reintervention (2.7% vs 14.5%, p = 0.049). CONCLUSIONS: Adjunctive MMAE following open surgery can lower the recurrence risks and reintervention rates for cSDH.

Middle Meningeal Artery Embolization with Isolated Use of Coils for Treatment of Chronic Subdural Hematomas: A Case Series.

BACKGROUND: Middle meningeal artery embolization (MMAE) is a novel approach for treatment of chronic subdural hematoma (cSDH). Studies comparing different procedural techniques for MMAE are lacking. It is unclear whether isolated use of coils results in suboptimal outcomes compared to when particle embolization is also performed. The objectives of this study are to describe the outcomes of coil-only MMAE and compare them with those of combined use of coils and particles. METHODS: A single-institution retrospective study of cSDH cases treated by MMAE was performed. Clinical outcomes, need for rescue surgery, and changes in hematoma's size were compared between the coil-only and coil + particle groups. RESULTS: Ninety-four hematomas in 78 patients were included. Twelve cases were treated by a coil-only MMAE procedure, often due to presence of dangerous ophthalmic collaterals. No treatment-related complications were observed in the coil-only group. There was no significant difference between the coil-only and coil + particle groups in baseline hematoma axial thickness, volume, midline shift, and duration of follow-up. The rate of need for rescue surgery was similar between the 2 groups (8.3% vs. 8.5%; P = 0.98). Coiling alone resulted in a similar percentage of reduction in cSDH volume (68.3% vs. 71.8%; P = 0.8) and rate of achieving ≥50% reduction in volume (81.8% vs. 76.3%; P = 0.68) compared to coils + particles. CONCLUSIONS: Isolated use of coils for endovascular treatment of cSDHs can be as effective as adjunct use of particle embolization. This method eliminates the risks of cranial nerve and visual complications associated with MMAE, can prevent procedural abortion due to presence of dangerous anastomoses, and reduces the technical complexity of the procedure.

Surgical Obliteration of a Posterior Fossa Dural Arteriovenous Fistula Presenting with Exclusive Spinal Signs and Symptoms Caused by Spinal Cord Venous Hypertension.

Vascular malformations in the dura of the spinal root sleeve in the thoracic or lumbar region can cause venous hypertension with resultant spinal cord edema and neurologic deterioration. However, occasionally an intracranial vascular malformation can have venous drainage into the spinal canal causing symptoms, signs, and radiographic appearance that can mimic spinal lesions. Herein, we present the case of a 73-year-old man who developed lower extremity weakness and loss of sensation. The patient initially underwent L4-L5 diskectomy elsewhere, but the symptoms progressed. Spinal magnetic resonance imaging revealed serpiginous vessels in the spinal subarachnoid space and spinal cord edema (Video 1). Diagnostic spinal and cerebral angiogram showed no evidence of spinal vascular malformations yet did reveal early venous shunting arising from the posterior fossa consistent with a dural arteriovenous fistula (dAVF). The venous drainage from this lesion was inferiorly directed into the spinal canal, causing venous hypertension of the spinal cord, which explained the patient's symptoms. An asymptomatic second dAVF of the petrous apex was also discovered. Surgical obliteration of both dAVFs in 1 sitting using a right far-lateral suboccipital craniotomy was planned. The dural drainage of each dAVF was identified and coagulated. Postoperative angiography confirmed complete obliteration of both dAVFs, and the patient's neurologic function improved shortly after surgery. This case highlights the importance of complete investigation of the spinal and cranial vasculature in the hunt for the cause of venous hypertension in the spinal cord.

Middle meningeal artery embolization for treatment of chronic subdural hematomas: does selection of embolized branches affect outcomes?

OBJECTIVE: Middle meningeal artery (MMA) embolization (MMAE) is a new therapeutic modality for chronic subdural hematoma (cSDH). There is limited evidence comparing various MMAE procedural techniques, resulting in significant variations in technique and procedural planning. The objective of this study was to compare outcomes of MMAE by the number and location of MMA branches that were embolized. METHODS: A single-center retrospective study of patients with cSDH treated by MMAE was conducted. Clinical outcomes, need for re-intervention, and changes in hematoma size were compared between different MMAE techniques. RESULTS: Ninety-four cSDHs in 78 patients were included. Embolization of the proximal trunk only, distal branches only, or proximal trunk plus distal branches resulted in similar rates of need for rescue surgery (7.4%, 13.0%, and 6.8%, respectively; p = 0.66) and rates of reducing the volume of the hematoma by at least 50% (74.1%, 80.0%, and 77.5%, respectively; p = 0.88). Embolization of only one branch had similar outcomes to embolization of more than one branch, as rescue surgery rates were 9.3% and 7.8% (p = 0.80), and rates ≥ 50% volume reduction were 75.6% and 78.3% (p = 0.76), respectively. Selective embolization of the dominant MMA branch was not associated with significantly different outcomes. CONCLUSIONS: Outcomes of distal, proximal, or combined proximal and distal MMAE in cSDH are not significantly different. Embolization of more than one branch is not associated with improved treatment efficacy. Arguably, targeting any location in the MMA provides sufficient flow restriction to enable spontaneous hematoma resolution. Accordingly, a technical planning algorithm for cSDH MMAE is suggested.

Case Report: Metastasis of a Trigeminal Malignant Peripheral Nerve Sheath Tumor to the Corpus Callosum.

BACKGROUND AND IMPORTANCE: Malignant peripheral nerve sheath tumors (MPNST) are relatively rare tumors of peripheral nerves that are notable for their locally aggressive nature, ability to metastasize, poor prognosis, and association with Neurofibromatosis type I. We present the case of a patient with a trigeminal nerve MPNST who developed an unusual metastasis to the corpus callosum, in the absence of any other central nervous system or systemic metastatic disease. We review the pathology and presentation of MPNST. CLINICAL PRESENTATION: A 53-yr-old woman presented with a 1-yr history of paroxysmal facial pain and dysesthesias in the right V1 and V2 distributions of the trigeminal nerve. She was initially diagnosed with trigeminal neuralgia although further imaging showed a cavernous sinus mass extending along the trigeminal nerve. She later developed an isolated lesion in the corpus callosum that was biopsied and consistent with MPNST. CONCLUSION: This case reviews the pathology and aggressive nature of MPNST and demonstrates an unusual site of metastasis. Clinicians should remain aware that MPNST can metastasize to sites in the central nervous system as well as systemically. Furthermore, clinicians should have a high index of suspicion for secondary causes of trigeminal neuralgia in cases with atypical features.

Early Identification of Traumatic Durotomy Associated with Atlantooccipital Dislocation May Prevent Retropharyngeal Pseudomeningocele Development.

Atlantooccipital dislocation can be complicated by a traumatic durotomy that may lead to the rare development of a retropharyngeal pseudomeningocele. To our knowledge this has been reported only five times previously. We present the case of a 60-year-old man involved in a motor vehicle accident who suffered an atlantooccipital dislocation and C5-C6 three-column injury. A unique MRI image of a defect in the ventral dura posterior to C2 was appreciated. He underwent occiput to T2 internal fixation and arthrodesis. During surgery, CSF egress was seen caudal to the right C2 nerve root. A DuraMatrix onlay patch reinforced with DuraSeal was placed to stop the CSF leak. A lumbar subarachnoid drain was also placed. The patient made a satisfactory recovery with residual mild weakness of his right upper extremity. In this report, we demonstrate that careful MRI review can reveal a ventral durotomy in a traumatic atlantooccipital dislocation and, if discovered, effective treatment including a lumbar subarachnoid drain for CSF diversion may prevent progression to a retropharyngeal pseudomeningocele. The literature on this rare presentation and associated durotomy is provided.