Transvenous Embolization of Dural Arteriovenous Fistulas Through the Galenic (Deep Venous) System: Multicenter Case Series and Meta-Analysis.

BACKGROUND AND OBJECTIVES: Arteriovenous fistulas involving the deep venous system have often been treated with microsurgery or transarterial embolization. Increasing familiarity with transvenous navigation and improved endovascular access systems may facilitate transvenous embolization (TVE) for these rare and challenging lesions. METHODS: We performed a retrospective study of neurointerventional databases of 6 high-volume centers. We identified all cases of arteriovenous fistulas with deep transvenous embolizations for arteriovenous fistula. Details regarding demographics, fistula characteristics, treatment considerations, clinical outcomes, and fistula occlusion were obtained and analyzed. The meta-analysis used the same inclusion criteria. RESULTS: Seventeen cases of TVE were identified. The most common reasons for TVE included prior treatment failure with microsurgery (n = 2) or transarterial embolization (n = 3) or inaccessible arterial pedicles (n = 4). For patients with full clinical outcome data (n = 14), 2 patients had worsened modified Rankin Scale, 8 patients had no change, and 4 were improved at a median clinical follow-up of 3.5 months. Angiographic obliteration was achieved in 15/17 cases (88.2%). In 1 case, catheterization around a sharp turn in the basal vein of Rosenthal could not be performed. In another case, despite successful TVE, there was residual lesion which was treated 1 year later by microsurgical clipping and excision. CONCLUSION: Transvenous approaches for embolization of deep arteriovenous fistulas have become possible with modern endovascular catheter systems and liquid embolics. These lesions can be treated safely and effectively through endovascular approaches, which may spare patients the traversal of deep structures needed for microsurgical approaches to these regions. The outcomes of TVE are comparable with published outcomes of microsurgical interruption.

Removal of a flanged ventricular catheter: illustrative case.

BACKGROUND: Flanged ventricular catheters were created in the 1970s to decrease shunt failure by preventing the holes at the catheter tip from contacting the choroid plexus. However, the flanges on the catheter frequently scarred within and tether to the choroid plexus, resulting in higher rates of intraventricular hemorrhage when removed. Today, flanged catheters are rarely encountered. OBSERVATIONS: The authors describe an illustrative case of a 7-year-old girl recently adopted from another country with a history of myelomeningocele and shunted hydrocephalus. She had been treated with a flanged catheter at birth. She presented with a shunt infection, which required removal of the flanged catheter tethered to the choroid. LESSONS: The authors illustrate the safe removal of a posterior-entry flanged ventricular catheter tethered to the choroid plexus using monopolar flexible electrocautery. The removal was monitored with a flexible endoscope inserted from an ipsilateral anterior burr hole and was followed by an endoscopic third ventriculostomy.

Epilepsy Surgery in Young Children With Tuberous Sclerosis Complex: A Novel Hybrid Multimodal Surgical Approach.

BACKGROUND: Surgery has become integral in treating children with tuberous sclerosis complex (TSC)-related drug-resistant epilepsy (DRE). OBJECTIVE: To describe outcomes of a multimodal diagnostic and therapeutic approach comprising invasive intracranial monitoring and surgical treatment and compare the complementary techniques of open resection and magnetic resonance-guided laser interstitial thermal therapy. METHODS: Clinical and radiographic data were prospectively collected for pediatric patients undergoing surgical evaluation for TSC-related DRE at our tertiary academic hospital. Seizure freedom, developmental improvement, and Engel class were compared. RESULTS: Thirty-eight patients (20 females) underwent treatment in January 2016 to April 2019. Thirty-five underwent phase II invasive monitoring with intracranial electrodes: 24 stereoencephalography, 9 craniotomy for grid/electrode placement, and 2 grids + stereoencephalography. With the multimodal approach, 33/38 patients (87%) achieved >50% seizure freedom of the targeted seizure type after initial treatment; 6/9 requiring secondary treatment and 2/2 requiring a third treatment achieved >50% freedom. The median Engel class was II at last follow-up (1.65 years), and 55% of patients were Engel class I/II. The mean age was lower for children undergoing open resection (2.4 vs 4.9 years, P = .04). Rates of >50% reduction in seizures (86% open resection vs 88% laser interstitial thermal therapy) and developmental improvement (86% open resection vs 83% magnetic resonance-guided laser interstitial thermal therapy) were similar. CONCLUSION: This hybrid approach of using both open surgical and minimally invasive techniques is safe and effective in treating DRE secondary to TSC. Clinical trials focused on treatment method with longer follow-up are needed to determine the optimal candidates for each approach and compare the treatment modalities more effectively.

Management strategies of unanticipated intracranial stenosis during mechanical thrombectomy for acute stroke: A survey of academic neurointerventionalists.

BACKGROUND: The optimal approach to the management of intracranial atherosclerotic disease (ICAD) at the time of mechanical thrombectomy (MT) for large vessel occlusion (LVO) remains controversial. The goal of this study is to characterize current practices concerning this challenging clinical situation in a survey of practicing neurointerventionalists. METHODS: An electronic questionnaire was sent to a cross-section of North American academic neurointerventionalists using publicly available contact information and departmental websites. Prior to analysis, responses were anonymized and categorized by region. RESULTS: A total of 136/360 responses were recorded from the U.S. and Canada. The mean number of years of practicing as a neurointerventionalist among the respondents was 10.5 (± 6.2 years). ICAD was perceived as a causative factor during MT for LVO in 5-10% of thrombectomy cases. The most common first-line treatment approach for significant ICAD, assuming a TICI 2b or better reperfusion, was medical therapy (77.9% of respondents), followed by angioplasty + stent placement (8.8% of respondents). There were no significant differences in the first line treatment of ICAD in LVO between geographical regions (p = 0.815). CONCLUSION: The approach to underlying ICAD in LVO varies widely; however, the majority of neurointerventionalists prefer medical therapy with DAPT as a first-line treatment approach. The current survey highlights the need for studies that better define the optimal timing and modality of treatment, along with an evidence-based framework for balancing the risks associated with these treatment approaches.

The impact of a night float system on operative experience in neurosurgery residency.

OBJECTIVE: Since the Accreditation Council for Graduate Medical Education (ACGME) implemented duty-hour restrictions in 2003, many residency programs have adopted a night float system to comply with time constraints. However, some surgical subspecialities have been concerned that use of a night float system deprives residents of operative experience. In this study, the authors describe their training program's transition to a night float system and its impact on resident operative experience. METHODS: The authors conducted a single-program study of resident surgical case volume before and after implementing the night float system at 3 of their 5 hospitals from 2014 to 2020. The authors obtained surgical case numbers from the ACGME case log database. RESULTS: Junior residents received a concentrated educational experience, whereas senior residents saw a significant decrease from 112 calls/year to 17. Logged cases significantly increased after implementation of the night float system (8846 vs 10,547, p = 0.04), whereas cases at non-night float hospitals remained the same. This increase was concurrent with an increase in hospital cases. This difference was mainly driven by senior resident cases (p = 0.010), as junior and chief residents did not show significant differences in logged cases (p > 0.40). Lead resident cases increased significantly after implementation of the night float system (6852 vs 8860, p = 0.04). When normalized for increased hospital cases, resident case increases were not statistically significant. CONCLUSIONS: Transitioning to a night float call system at the authors' institution increased overall resident operative cases, particularly for lead resident surgeons. Based on the results of this study, the authors recommend the use of a night float call system to consolidate night calls, which increases junior resident-level educational opportunities and senior resident cases.

3-Dimensional Modeling in Virtual Reality for Resection of a Pineal Region Falcotentorial Meningioma.

We present a parietal interhemispheric approach to resect a pineal region falcotentorial meningioma. Three-dimensional (3D) modeling was used to visualize and plan the surgical approach in virtual reality (Video 1). A 78-year-old woman was incidentally found to have a slow-growing falcotentorial meningioma. The tumor was first treated with stereotactic radiosurgery, but the patient had progressive confusion, memory issues, and bilateral temporal field cuts with interval expansion of the tumor and significantly increased peritumoral vasogenic edema on magnetic resonance imaging. After recommending tumor resection, the patient consented to surgery and underwent resection via a posterior interhemispheric subsplenial approach. Using a 3D model in virtual reality, we discuss the advantages and disadvantages of various classical approaches to the pineal region for resection of this tumor.1-3 Falcotentorial meningiomas often displace the deep veins inferiorly, making an interhemispheric approach more favorable.4-6 Preoperative visualization of critical deep venous structures with the 3D model was a valuable adjunct to magnetic resonance imaging for achieving safe resection. We depict key steps of the surgical planning process using virtual reality and demonstrate how simulation can be used to evaluate risks and benefits of different surgical corridors. A small rim of residual tumor adherent to the deep cerebral veins was intentionally left behind in order to minimize risk of morbidity to the patient.7 At 1-month follow-up, the patient's cognition had returned to baseline and her vision had significantly improved. Ultimately, surgical planning using virtual reality promotes both neurosurgical education and patient safety through clear visualization and understanding of different surgical approaches.

Trapping and P2-P3 Posterior Inferior Cerebellar Artery Reanastomosis for Treatment of a Ruptured Fusiform Aneurysm: Application of Fourth-Generation Technique: 2-Dimensional Operative Video.

Aneurysms of the posterior inferior cerebellar artery (PICA) represent the second most common posterior circulation aneurysm and commonly have complex morphology. Various bypass options exist for PICA aneurysms,1-6 depending on their location relative to brainstem perforators and the vertebral artery, and the presence of nearby donor arteries. We present a case of a man in his late 40s who presented with 3 d of severe headache. He was found to have a fusiform right P2-segment PICA aneurysm. Preoperative angiogram demonstrated the aneurysm and a redundant P3 caudal loop that came in close proximity to the healthy P2 segment proximal to the aneurysm. The risks and benefits of the procedure were discussed with the patient, and they consented for a right far lateral approach craniotomy with partial condylectomy for trapping of the aneurysm with bypass. The aneurysm was trapped proximally and distally. The P3 was transected just distal to the aneurysm and brought toward the proximal P2 segment, facilitated by a lack of perforators on this redundant distal artery. An end-to-side anastomosis was performed. Postoperative angiogram demonstrated exclusion of the aneurysm and patent bypass. The patient recovered well and remained without any neurological deficit at 6-mo follow-up. This case demonstrates the use of a "fourth-generation"5,7,8 bypass technique. These techniques represent the next innovation beyond third-generation intracranial-intracranial bypass. In this type 4B reanastomosis bypass, an unconventional orientation of the arteries was used. Whereas reanastomosis is typically performed end-to-end, the natural course of these arteries and the relatively less-mobile proximal P2 segment made end-to-side the preferred option in this case. Fourth-generation bypass techniques open up more configurations for reanastomosis, using the local anatomy to the surgeon's advantage. The patient consented to the described procedure and consented to the publication of their image.

Genomic Analysis of Posterior Fossa Meningioma Demonstrates Frequent AKT1 E17K Mutations in Foramen Magnum Meningiomas.

Objective Posterior fossa meningiomas are surgically challenging tumors that are associated with high morbidity and mortality. We sought to investigate the anatomical distribution of clinically actionable mutations in posterior fossa meningioma to facilitate identifying patients amenable for systemic targeted therapy trials. Methods Targeted sequencing of clinically targetable AKT1 , SMO , and PIK3CA mutations was performed in 61 posterior fossa meningioma using Illumina NextSeq 500 to a target depth of >500 × . Samples were further interrogated for 53 cancer-relevant RNA fusions by the Archer FusionPlex panel to detect gene rearrangements. Results AKT 1 ( E17K ) mutations were detected in five cases (8.2%), four in the foramen magnum and one in the cerebellopontine angle. In contrast, none of the posterior fossa tumors harbored an SMO ( L412F ) or a PIK3CA ( E545K ) mutation. Notably, the majority of foramen magnum meningiomas (4/7, 57%) harbored an AKT1 mutation. In addition, common clinically targetable gene fusions were not detected in any of the cases. Conclusion A large subset of foramen magnum meningiomas harbor AKT1 E17K mutations and are therefore potentially amenable to targeted medical therapy. Genotyping of foramen magnum meningiomas may enable more therapeutic alternatives and guide their treatment decision process.

Vascularized Iliac Bone Graft for Complex Closure During Spinal Deformity Surgery.

Spinal pseudarthrosis is failure of bony union across a segment where arthrodesis has been attempted. A variety of treatment approaches have been proposed to promote bony union, including use of vascularized bone graft. We report a successful application of vascularized pedicled iliac crest bone graft (ICBG) to treat recurrent lumbar and sacral pseudarthrosis. The vascularized ICBG offers the advantages of biocompatibility, mechanical stability, and minimal antigenicity. Vascularized bone transfers to the spine undergo fusion without resorption, even in the presence of compressive and rotatory forces. With its ease of access within the operative field and limited donor site morbidity, vascularized ICBG is an ideal orthobiologic that expedites time to bony union.