Current Indications, Trends, and Long-Term Results of 233 Bypasses to Treat Complex Intracranial Aneurysms: A Location-Specific Analysis.

BACKGROUND AND OBJECTIVES: Advances in endovascular flow diverters have led to a secular shift in the management of brain aneurysms, causing debate on current bypass indications. We therefore sought to investigate the long-term results, current indications, and trends of bypasses for brain aneurysms. METHODS: We retrospectively reviewed bypasses performed between 2005 and 2022 to treat brain aneurysms. Demographic, clinical, and radiological data were collected till the most recent follow-up. Aneurysm occlusion and graft patency was noted on cerebral angiogram in the immediate postoperative, 3-month, and most recent follow-up periods. Clinical outcomes (modified Rankin scores) and complications were assessed at 3 month and most recent follow-up. Trends in bypass volume and graft patency were assessed in 5-year epochs. Results were dichotomized based on aneurysm location to generate location-specific results and trends. RESULTS: Overall, 203 patients (mean age 50 years, 57% female patients) with 207 cerebral aneurysms were treated with 233 cerebral bypasses with a mean follow-up of 2 years. Fusiform morphology was the most common bypass indication. Aneurysm occlusion on immediate postoperative and final follow-up angiogram was 89% (184/207) and 96% (198/207), respectively. Graft patency rate in the immediate postoperative period and most recent follow-up was 95% (222/233) and 92% (215/233), respectively. Of 207 aneurysms, 5 (2%) recurred. Of 203 patients, 81% (165) patients had modified Rankin scores of 0-2 at the 3-month follow-up and 11 patients died (mortality 5%). Although there was a steady decrease in the bypass volume over the study period, the proportion of bypasses for recurrent aneurysms increased serially. Posterior circulation aneurysms had lower rates of aneurysm occlusion and significantly higher incidence of postoperative strokes and deaths (P = .0035), with basilar artery aneurysms having the worst outcomes. CONCLUSION: Bypass indications have evolved with the inception of novel flow diverters. However, they remain relevant in the cerebrovascular surgeon's armamentarium, and long-term results are excellent.

High-Flow Bypass and Clip Trapping of a Giant Fusiform Middle Cerebral Artery (M1) Aneurysm: Technical Case Instruction.

BACKGROUND AND IMPORTANCE: Giant intracranial aneurysms have a poor natural history with mortality rates of 68% and 80% over 2-year and 5-year, respectively. Cerebral revascularization can provide flow preservation while treating complex aneurysms requiring parent artery sacrifice. In this report, we describe the microsurgical clip trapping and high-flow bypass revascularization for a giant middle cerebral artery (MCA) aneurysm. CLINICAL PRESENTATION: A 19-year-old man was diagnosed with a giant left MCA aneurysm after he suffered a left hemispheric capsular stroke 6 months ago. Since then, the patient recovered from the right hemiparesis and dysarthria with residual symptoms. Neuroimaging demonstrated a giant fusiform aneurysm encompassing the entire M1 segment. The bilobed aneurysm measured 37 × 16 × 15 mm. Endovascular treatment options included partial coiling of the aneurysm followed by deployment of flow-diverting stent spanning from the M2 branch-through the aneurysm neck-into the internal carotid artery. Because of the high risk of lenticulostriate artery stroke with endovascular treatment, the patient opted for microsurgical clip trapping and bypass. The patient consented to the procedure. High-flow bypass from internal carotid artery to M2 MCA was performed using radial artery graft, followed by aneurysm clip trapping using 3 clips. CONCLUSION: We demonstrate the successful microsurgical treatment for a complex case of giant M1 MCA aneurysm with fusiform morphology. High-flow revascularization using radial artery graft helped in achieving good clinical outcome with complete aneurysm occlusion with flow preservation despite the challenging morphology and location. Cerebral bypass continues to be a useful tool to tackle complex intracranial aneurysms.

High-Flow Saphenous Vein Graft Bypass from Common Carotid Artery to Vertebral Artery (V2) for the Treatment of Vertebrobasilar Insufficiency Due to Bilateral Vertebral Artery Origin Stenosis.

Vertebrobasilar insufficiency can lead to devastating brainstem and posterior cerebral infarction without timely treatment.1 A 56-year-old man with a history of hypertension, hyperlipidemia, and diabetes mellitus presented to the clinic with right hemiparesis due to previous left cerebral hemispheric stroke. He also harbored a giant asymptomatic parieto-occipital meningioma incidentally diagnosed 2 years ago. Neuroimaging showed old left cerebral infarcts and a tumor that had remained stable in size. Cerebral angiography identified bilateral vertebral artery stenosis near their origin from the subclavian arteries with severe vertebrobasilar insufficiency. There was some collateral flow to the posterior cortex via the internal maxillary and occipital artery branch anastomoses. Despite recommendation, the patient decided to not undergo tumor resection, but opted for a high-flow bypass to the posterior circulation to prevent stroke. We used a saphenous vein graft to perform a high-flow extracranial-to-extracranial bypass revascularization of the ischemic vertebrobasilar circulation (Video 1). The patient tolerated the procedure well and was discharged without new deficits 4-days postoperatively. Most recent follow-up examination at 3 years after surgery revealed a patent bypass graft with no new adverse cerebrovascular events. The tumor remains asymptomatic without change in imaging characteristics. Cerebral bypasses remain useful tools in carefully selected patients for the treatment of complex aneurysms, complex tumors, and ischemic cerebrovascular diseases.2-7 We demonstrate an extracranial-to-extracranial high-flow bypass to revascularize the posterior cerebral circulation using a saphenous vein graft in a patient with vertebrobasilar insufficiency.

Orbitozygomatic Transsylvian and Subtemporal Transzygomatic Approaches for Clipping of Basilar Tip Aneurysms: 2-Dimensional Operative Video.

INDICATIONS CORRIDOR AND EXPOSURE: The orbitozygomatic transsylvian approach is ideal for basilar tip aneurysms (BTAs) ≤15 mm located at or above the level of posterior clinoid process (PCP), whereas for larger, low-lying BTA's with fetal posterior cerebral artery (PCA), the subtemporal transzygomatic approach is preferred. Both approaches expose the basilar tip area and structures in the interpeduncular fossa from an anterolateral angle and the lateral angle, respectively. ANATOMIC ESSENTIALS NEED FOR PREOPERATIVE PLANNING AND ASSESSMENT: Aneurysm size and level, brainstem perforators, and PCA size (fetal or not) should be noted preoperatively. ESSENTIAL STEPS OF THE PROCEDURE: A. Orbitozygomatic transsylvian approach1. Frontotemporal craniotomy with posterolateral orbitotomy.2. Extradural optic nerve decompression and anterior clinoidectomy.3. Transsylvian dissection and carotid-optic cistern decompression.4. Distal dural ring opening.5. Aneurysm exposure and clipping.OrB. Subtemporal transzygomatic approach 11. Frontotemporal incision with zygomatic osteotomy.2. Temporal lobe retraction, subtemporal dissection, and tentorial division.3. Cavernous sinus opening and dorsum sellae drilling.4. Petrous apex resection.5. Aneurysm exposure and clipping. PITFALLS/AVOIDANCE OF COMPLICATIONS: Complications such as cranial nerve injury, perforator stroke, aneurysm rupture, and hemorrhage can be prevented by neuromonitoring, avoiding temporary basilar occlusion for >10 minutes, use of transient adenosine arrest during clipping, and interposing rubber dam between perforators and aneurysm. 1. VARIANTS AND INDICATIONS OF THEIR USE: Cavernous sinus opening with posterior clinoidectomy and dorsum sellae drilling may be performed if aneurysm neck is at or below the level of PCP. 1-7The patient consented to the procedure.

Microsurgical Clipping of a Ruptured Wide-Neck Basilar Tip Aneurysm by an Extended Transsylvian Transcavernous Approach: 2-Dimensional Operative Video.

Basilar tip aneurysms are difficult to treat due to their deep location, proximity to cranial nerves and brainstem, and risk of perforator stroke.1-3 A 49-year-old woman presenting to the emergency department with subarachnoid hemorrhage was found to have a wide-neck basilar tip aneurysm measuring 8.6 mm × 5.6 mm × 7.6 mm. The aneurysm had a 4.9-mm wide neck located at the level of the dorsum sellae.4,5 Microsurgical clipping was recommended to the patient due to the complexity of the aneurysm neck, the patient's young age, the expertise of the surgical-anesthetic team, treatment durability, and the low risk of recurrence.2,6-9 We used an extended transsylvian transcavernous approach to expose the aneurysm (Video 1). We preferred this anterolateral approach over the more lateral subtemporal transzygomatic approach because of its versatility in providing better visualization of the bilateral posterior cerebral arteries and superior cerebellar arteries.10 The surgical exposure to the proximal basilar artery was gained by drilling the posterior clinoid process and dorsum sellae. Two titanium clips were applied across the aneurysm neck, and indocyanine green angiography confirmed complete aneurysm obliteration. Protection of critical brainstem perforators was ensured using the rubber-dam technique. The patient tolerated the procedure well with no deficits at the 12-month follow-up. We review the microsurgical nuances of treating complex wide-neck basilar tip aneurysms that are not good candidates for endovascular treatment. Although endovascular tools are favored as the first-line treatment choice for most cerebral aneurysms, microsurgical clipping techniques remain an important tool in the contemporary cerebrovascular neurosurgeon's toolkit.2,6,11-15.

Operative Technique and Complication Management in a Case of Giant Esthesioneuroblastoma Resected by a Combined Transcranial and Endonasal Endoscopic Approach: Technical Case Report.

BACKGROUND AND IMPORTANCE: Esthesioneuroblastoma (ENB) is a rare anterior skull base tumor derived from olfactory epithelium. There are very few operative videos in the literature demonstrating the surgical resection techniques for giant ENB because of their rarity and complexity. In this technical report, we demonstrate the microsurgical resection of a very large and complex high-grade ENB, initially deemed unresectable, through a bifrontal craniotomy and extended subfrontal approach combined with an endonasal endoscopic approach. CLINICAL PRESENTATION: A 34-year-old woman presented with headaches, nasal congestion, and bloody nasal drainage. MRI showed a large nasal cavity mass with extension into the anterior cranial fossa and bifrontal lobes. There was significant bifrontal edema causing headaches and abutting the optic nerves. Initial management with surgical resection was offered to the patient for local tumor control and to preserve her vision. A combined bifrontal craniotomy and endonasal transsphenoidal approach was used for resecting this giant tumor. After achieving gross total resection, we reconstructed the anterior skull base in layers. She developed several postoperative complications which were appropriately managed. CONCLUSION: We demonstrate the surgical resection of a giant ENB through a combined transcranial and endonasal endoscopic approach. We discuss the several postoperative complications in this complex case and the lessons learned.

Incidence and Risk Model of Venous Thromboembolism in Patients with Aneurysmal Subarachnoid Hemorrhage.

OBJECTIVE: Venous thromboembolism (VTE) is a significant source of morbidity and mortality in hospitalized patients. We describe our experience with VTE prophylaxis and treatment in patients with aneurysmal subarachnoid hemorrhage (aSAH), risk factors for VTE, and a hazard model describing the daily risk of VTE. METHODS: A retrospective cohort study was performed on patients with aSAH admitted from 2014 to 2018. Patients were screened for VTE based on clinical suspicion. Demographics, perioperative data, and in-hospital data were assessed as risk factors for VTE using survival analysis with death as a competing risk. RESULTS: Among 485 patients, the overall incidence of VTE, deep vein thrombosis, and pulmonary embolism were 5.6%, 4.3%, and 2.3%, respectively. Increasing length of stay in the intensive care unit (hazard ratio [HR], 1.79; P < 0.0001; 95% confidence interval [CI], 1.49-2.16) and ventilation immediately after aneurysm treatment was associated with VTE (HR, 8.87; P < 0.01; 95% CI, 1.86-42.38). Hunt and Hess grade was negatively associated with VTE (HR, 0.61; P = 0.045; 95% CI, 0.37-1.00) due to its increased association with the competing risk of death (HR, 2.57; P < 0.0001; 95% CI, 1.89-3.49). The adjusted 4-year cumulative incidence for VTE is 11.1% and at mean day of hospital discharge is 5.4%. Treatment of VTEs with anticoagulation and/or inferior vena cava filter placement was not associated with immediate complications. CONCLUSIONS: We describe the largest single-institution cohort of VTEs in aSAH patients. Our hazard model quantifies the cumulative incidence of VTEs during the course of hospitalization. We suggest a standardized protocol for screening, prophylaxis, and treatment of VTEs in this patient population.

Embolization and Resection of Epidural Spinal Arteriovenous Malformations: Case Report.

BACKGROUND AND IMPORTANCE: Spinal vascular malformations (sVMs) are relatively uncommon, accounting for 5% to 10% of all spinal cord lesions. Spetzler and Kim developed a paradigm to classify sVMs based on a variety of characteristics into 1 of 6 types, including a subcategory for exclusively epidural sVMs. There is a paucity of literature focused on this category, specifically sources describing the clinical manifestation and management of these lesions. CLINICAL PRESENTATION: We report 2 cases of purely epidural spinal arteriovenous fistula, with an emphasis on the radiographic features and combined endovascular and microsurgical treatment. We report 2 patients known to have epidural spinal arteriovenous fistula who underwent both embolization and surgical resection between May 2019 and August 2020 at our institution. Data collected included demographic, clinical, and operative course, including age, sex, medical history, presenting symptoms, and preoperative and postoperative imaging. Both of these patients were managed with a combination of an endovascular approach for embolization of feeding arterial source and surgical exploration/resection. In both cases, no residual vascular malformation was identified, and the patients went on to be symptom free after 6 weeks. CONCLUSION: This report describes the use of a combination of endovascular and surgical approaches to achieve maximal benefit for 2 patients. These cases reinforce the value of a staged multimodal treatment approach in achieving good functional outcomes for patients with these rare and challenging entities.

Ophthalmic artery reversal predicts contralateral body weakness symptoms better than carotid Doppler velocity-preliminary results.

Background: The measurement of blood velocity in the carotid artery has been the most popular noninvasive method of identifying and classifying carotid stenosis for half a century. Carotid stenosis is an indicator of elevated risk of stroke; anatomic revascularization reduces the chance of stroke by more than half. Controversy persists on how patients with severe carotid stenosis should be selected for anatomic revascularization. Patients with a connected circle of Willis (coW) might not benefit from anatomic revascularization; patients with two segments missing in the coW are most likely to benefit from revascularization. Methods: Based on this analysis of data from carotid duplex examinations and transcranial Doppler examinations including ophthalmic artery (OA) direction in 28 patients, a refined carotid examination protocol is proposed. This refinement includes Doppler measurement of OA flow direction and documentation of internal carotid artery (ICA) bruit in addition to the adoption of an ICA peak systolic velocity (PSV) criterion exceeding 350 cm/s for identification of the patient most likely to benefit from carotid stenosis treatment. Results: Sensitivity and specificity of OA direction or carotid bruit are 84.6%±5.4%, 71.4%±2.1% and for PSV >350 cm/s are 84.6%±5.4%, 59.5%±2.3% for predicting contralateral body weakness. Conclusions: The proposed examination can be performed with the same duplex scanner and scan head currently used for carotid examinations with little additional time.

Angiographically Silent Ruptured Dural Arteriovenous Fistula Presenting As Subdural Hematoma.

Dural arteriovenous fistulas (dAVF) are aberrant vascular communications that can have devastating effects ranging from headaches to death. Typically, these malformations are identifiable on a CT angiogram (CTA) and confirmed via catheter angiography. We present a case of a female patient who presented with a headache and was found to have a large holohemispheric subdural hematoma. Given the lack of trauma, a CTA was performed. The CTA revealed abnormal vessels in the anterior temporal lobe spanning her hematoma. A diagnostic cerebral angiogram was performed; no early venous drainage was detected. When the patient was taken to the operating room for subdural hematoma evacuation, an aberrant connection from a superficial cortical vein to the middle meningeal artery was identified and ligated. Although rare, this case demonstrates that patients can present with ruptured vascular malformations that are radiographically silent on cerebral angiography.

Traumatic Pseudoaneurysm of the Occipital Artery Treated with Open Surgical Ligation: 2-Dimensional Operative Video.

Scalp pseudoaneurysms occur most commonly because of trauma and are often in the superficial temporal artery due to the lack of soft tissue coverage between skin and bone, making it more vulnerable anatomically.1,2 Pseudoaneurysms of the occipital artery (OA) also occur but are extremely rare.2-4 An 80-year-old man presented with scalp bleeding and a small left-sided posterior scalp laceration after a fall and head strike 10 days prior. He was admitted and during his 2-week hospital stay, the occipital laceration continued to rebleed (Video 1). He developed a 2-cm pulsatile ulcerative mass with central necrosis on the left nuchal ridge. Computed tomography angiography revealed an ovoid left occipital lesion measuring 1.3 × 2.5 × 2.3 cm with delayed contrast filling and partial thrombosis. The base of the lesion had dense contrast filling continuous with the OA, diagnostic of OA pseudoaneurysm. OA pseudoaneurysm may be treated endovascularly or surgically. While surgical resection is the most common treatment, minimally invasive techniques have been successfully done through direct injection of N-butyl cyanoacrylate or endovascular embolization. The clinical presentation of this case was unique because this patient had an ulcerated lesion with central necrosis overlying the pseudoaneurysm. Endovascular management alone would not address the open lesion, which is at high risk for infection. The risk of infection would increase after embolization of the occipital artery, causing further necrosis of the tissue.

De novo epilepsy after microsurgical resection of brain arteriovenous malformations.

OBJECTIVE: Seizures are the second most common presenting symptom of brain arteriovenous malformations (bAVMs) after hemorrhage. Risk factors for preoperative seizures and subsequent seizure control outcomes have been well studied. There is a paucity of literature on postoperative, de novo seizures in initially seizure-naïve patients who undergo resection. Whereas this entity has been documented after craniotomy for a wide variety of neurosurgically treated pathologies including tumors, trauma, and aneurysms, de novo seizures after bAVM resection are poorly studied. Given the debilitating nature of epilepsy, the purpose of this study was to elucidate the incidence and risk factors associated with de novo epilepsy after bAVM resection. METHODS: A retrospective review of patients who underwent resection of a bAVM over a 15-year period was performed. Patients who did not present with seizure were included, and the primary outcome was de novo epilepsy (i.e., a seizure disorder that only manifested after surgery). Demographic, clinical, and radiographic characteristics were compared between patients with and without postoperative epilepsy. Subgroup analysis was conducted on the ruptured bAVMs. RESULTS: From a cohort of 198 patients who underwent resection of a bAVM during the study period, 111 supratentorial ruptured and unruptured bAVMs that did not present with seizure were included. Twenty-one patients (19%) developed de novo epilepsy. One-year cumulative rates of developing de novo epilepsy were 9% for the overall cohort and 8.5% for the cohort with ruptured bAVMs. There were no significant differences between the epilepsy and no-epilepsy groups overall; however, the de novo epilepsy group was younger in the cohort with ruptured bAVMs (28.7 ± 11.7 vs 35.1 ± 19.9 years; p = 0.04). The mean time between resection and first seizure was 26.0 ± 40.4 months, with the longest time being 14 years. Subgroup analysis of the ruptured and endovascular embolization cohorts did not reveal any significant differences. Of the patients who developed poorly controlled epilepsy (defined as Engel class III-IV), all had a history of hemorrhage and half had bAVMs located in the temporal lobe. CONCLUSIONS: De novo epilepsy after bAVM resection occurs at an annual cumulative risk of 9%, with potentially long-term onset. Younger age may be a risk factor in patients who present with rupture. The development of poorly controlled epilepsy may be associated with temporal lobe location and a delay between hemorrhage and resection.

Primary Intracranial Brainstem Malignant Melanoma: A Technical Case Report.

BACKGROUND AND IMPORTANCE: Primary intracranial malignant melanomas (PIMMs) are quite rare, comprising 1% of melanomas and 0.07% of intracranial tumors. PIMMs have been reported in a variety of intracranial locations, but there has only been 1 reported instance of PIMM occurring in the brainstem. In this study, we describe the second reported case of primary pontine malignant melanoma and its treatment. CLINICAL PRESENTATION: A 40-year-old man presented with right hemiparesis, diplopia, and dysarthria. MRI demonstrated a hemorrhagic, expansile, and heterogeneously enhancing lesion in the left pons with edema extending to the left thalamus and posterior limb of the internal capsule. Surgical resection was performed through a transpetrosal approach. Pathology resulted as malignant melanoma immunopositive for BRAF V600E mutation. Complete oncological workup revealed no other lesions; thus, he was diagnosed with PIMM of the brainstem. CONCLUSION: We report a rare case of primary pontine malignant melanoma in which microsurgical resection resulted in dramatic clinical improvement despite the challenging location. This is only the second reported case of brainstem PIMM. More patients with longer-term follow-up will be necessary to determine the best treatment approach.