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.

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.

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.

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 (VBI) can lead to devastating brainstem and posterior cerebral infarction without timely treatment.¹ A 56-year-old man with 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 parietooccipital 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 saphenous vein graft to perform a high-flow extracranial-to-extracranial bypass revascularization of the ischemic vertebrobasilar circulation as demonstrated in the operative video. The patient tolerated the procedure well and was discharged without new deficits 4-days post-op. Most recent follow-up 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 continue to remain useful tools in carefully selected patients for the treatment of complex aneurysms, complex tumors and ischemic cerebrovascular diseases.^2-7 In this report, we demonstrate an extracranial-to-extracranial high-flow bypass to revascularize the posterior cerebral circulation using a saphenous vein graft in a patient with VBI.

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 approach.

Frontotemporal craniotomy with posterolateral orbitotomy.

Extradural optic nerve decompression and anterior clinoidectomy.

Transsylvian dissection and carotid-optic cistern decompression.

Distal dural ring opening.

Aneurysm exposure and clipping.Or.

B

Subtemporal transzygomatic approach1.

Frontotemporal incision with zygomatic osteotomy.

Temporal lobe retraction, subtemporal dissection, and tentorial division.

Cavernous sinus opening and dorsum sellae drilling.

Petrous apex resection.

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.

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.

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.

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.

Concurrent decompression and resection versus decompression with delayed resection of acutely ruptured brain arteriovenous malformations

OBJECTIVE

Brain arteriovenous malformations (bAVMs) most commonly present with rupture and intraparenchymal hemorrhage. In rare cases, the hemorrhage is large enough to cause clinical herniation or intractable intracranial hypertension. Patients in these cases require emergent surgical decompression as a life-saving measure. The surgeon must decide whether to perform concurrent or delayed resection of the bAVM. Theoretical benefits to concurrent resection include a favorable operative corridor created by the hematoma, avoiding a second surgery, and more rapid recovery and rehabilitation. The objective of this study was to compare the clinical and surgical outcomes of patients who had undergone concurrent emergent decompression and bAVM resection with those of patients who had undergone delayed bAVM resection.

METHODS

The authors conducted a 15-year retrospective review of consecutive patients who had undergone microsurgical resection of a ruptured bAVM at their institution. Patients presenting in clinical herniation or with intractable intracranial hypertension were included and grouped according to the timing of bAVM resection: concurrent with decompression (hyperacute group) or separate resection surgery after decompression (delayed group). Demographic and clinical characteristics were recorded. Groups were compared in terms of the primary outcomes of hospital and intensive care unit (ICU) lengths of stay (LOSs). Secondary outcomes included complete obliteration (CO), Glasgow Coma Scale score, and modified Rankin Scale score at discharge and at the most recent follow-up.

RESULTS

A total of 35/269 reviewed patients met study inclusion criteria; 18 underwent concurrent decompression and resection (hyperacute group) and 17 patients underwent emergent decompression only with later resection of the bAVM (delayed group). Hyperacute and delayed groups differed only in the proportion that underwent preresection endovascular embolization (16.7% vs 76.5%, respectively; p < 0.05). There was no significant difference between the hyperacute and delayed groups in hospital LOS (26.1 vs 33.2 days, respectively; p = 0.93) or ICU LOS (10.6 vs 16.1 days, respectively; p = 0.69). Rates of CO were also comparable (78% vs 88%, respectively; p > 0.99). Medical complications were similar in the two groups (33% hyperacute vs 41% delayed, p > 0.99). Short-term clinical outcomes were better for the delayed group based on mRS score at discharge (4.2 vs 3.2, p < 0.05); however, long-term outcomes were similar between the groups.

CONCLUSIONS

Ruptured bAVM rarely presents in clinical herniation requiring surgical decompression and hematoma evacuation. Concurrent surgical decompression and resection of a ruptured bAVM can be performed on low-grade lesions without compromising LOS or long-term functional outcome; however, the surgeon may encounter a more challenging surgical environment.

Hypoglossal Nerve Schwannoma With Severe Brainstem Compression: Microsurgical Excision by Extreme Lateral Approach: 2-Dimensional Operative Video

A 37-yr-old male presented with a history of left-sided tongue atrophy and fasciculations and weakness of upper limbs for 3 mo. Magnetic resonance imaging (MRI) revealed a large, partially cystic tumor with severe compression of the brainstem and spinal cord, with expansion and erosion of the hypoglossal canal. Computed tomography (CT) angiography showed the left vertebral artery to be anteriorly displaced by the tumor.  A retrosigmoid craniotomy and craniectomy were performed followed by mastoidectomy with unroofing the posterior aspect of the sigmoid sinus. The foramen magnum was completely unroofed. The hypoglossal canal was exposed with a diamond drill and an ultrasonic bone curette, and a tumor was seen within the expanded canal. C1 lamina was removed partially in the lateral aspect, and the occipital condyle was partially removed. After opening the dura mater, the tumor was found to be stretching the eleventh cranial nerve. The tumor was debulked, and dissected from the cranial nerve fibers. The vertebral artery, anterior spinal artery, and other branches displaced by the tumor were carefully preserved. The tumor was removed from the hypoglossal canal with a curette. The patient recovered well, with the resolution of his upper limb weakness. Patient modified Rankin Scale was 1 at 6-mo follow-up. The postoperative MRI showed a small remnant inside the hypoglossal canal, and it was treated by radiosurgery.  This 2-dimensional video demonstrates the technique of complete microsurgical removal of a complex tumor with preservation of cranial nerves and vertebral artery.  Informed consent was obtained from the patient prior to the surgery, which included videotaping of the procedure and its distribution for educational purposes. Also, all relevant patient identifiers have been removed from the video and accompanying radiology slides.

Largest neurosurgical social media group and its impact on communication and research

BACKGROUND

The use of social media to communicate and disseminate knowledge has increased exponentially, especially in the field of neurosurgery. 'Neurosurgery cocktail' (NC) was developed by a group of young neurosurgeons as a means of sharing didactic materials and clinical experiences via social media. It connects 35.000 neurosurgeons worldwide on multiple platforms, primarily Facebook and Twitter. Given the rising utilization of social media in neurosurgery, the popularity of NC has also increased since its inception. In this study, the authors surveyed the social media analytics of NC for both Facebook and Twitter. Besides, we reviewed the literature on the use of social media in neurosurgery.

METHODS

Facebook and Twitter metrics were extracted through each respective platform's analytics tools from December 2020 (earliest available date for data analysis) through January 2021. A literature search was conducted using PubMed (MEDLINE) and Scopus databases.

RESULTS

On Facebook, as of January 2021, the group had a total of 25.590 members (87.6% male), most commonly (29%) between 35 and 44 years of age with over 100 countries were represented. As of January 2021, they had amassed 6457 followers on Twitter. During the last 28 d between December 2020 and January 2021, the account published 65 tweets that garnered a total of 196,900 impressions. Twelve articles were identified in our literature review on the use of social media within the neurosurgical community.

CONCLUSIONS

NC is one of the most widely utilized neurosurgical social media resources available. Sharing knowledge has been broadened thanks to the recent social media evolution, and NC has become a leading player in disseminating neurosurgical knowledge.

Distal Basilar Artery "Umbrella Aneurysm" Treated by Radial Artery Graft Bypass From the External Carotid Artery to Posterior Cerebral Artery and Clip Trapping: 2-Dimensional Operative Video

A 71-yr-old woman was discovered to have an incidental distal basilar artery (BA) fusiform aneurysm 7 × 5 mm in dimension, shaped like an "umbrella handle" with critical stenosis distal to the aneurysm. The right posterior cerebral artery (PCA) P1 segment was small; the left posterior communicating artery (PComA) was miniscule. Because the natural history of fusiform BA aneurysms is poorly defined, this was equated to a saccular aneurysm, with an estimated 10-yr rupture rate of 29%.1-8 After discussion of alternative treatments, the patient decided upon surgery. Because of inadequate collateral circulation, a bypass to the left PCA was deemed necessary.  The aneurysm was exposed by an extended trans-sylvian approach, and the left PCA P2 segment was visualized subtemporally. The left radial artery (RAG) was extracted, and pressure distended to prevent vasospasm. The RAG bypass was sutured first to the P2, and then to the cervical external carotid artery (ECA); the BA aneurysm was then clipped. The proximal anastomosis of the bypass needed revision because of poor flow; a 4-mm punch hole was made to widen the arteriotomy on the ECA. The patient was discharged home with mild memory loss and partial left cranial nerve III palsy. After discharge, she developed a severe left hemicrania, resolved with gabapentin. At 6-wk follow-up, she was asymptomatic, and computed tomography (CT) angiogram demonstrated patency of the bypass.  The patient gave informed consent for surgery and video recording. All relevant patient identifiers have been removed from the video and accompanying radiology slides.

Cavernous Sinus Meningioma: Tumor Decompression for Trigeminal Neuralgia and Anterior Tibial Artery Graft High-Flow Bypass for Brain Ischemia: 2-Dimensional Operative Video

A 62-yr-old man with left cavernous sinus tumor presented with atypical trigeminal neuralgia refractory to medical treatment. He received Gamma Knife (Elekta) radiation for the tumor. However, the facial pain worsened after radiation. Neuropsychological testing done for memory problems had revealed mild neurocognitive disorder. Neurological examination showed trigeminal distribution numbness and partial abducens nerve paralysis. Imaging revealed an enhancing left cavernous sinus and supra-cavernous mass. Angiography revealed severe stenosis of the left cavernous internal carotid artery (ICA). Computed tomography (CT) perfusion study showed diminished blood flow on the left side, and ischemic changes were seen in fluid-attenuated inversion-recovery (FLAIR) magnetic resonance imaging (MRI).  Surgical resection of the tumor was preferred over ablative treatment for trigeminal neuralgia because of its effectiveness in improving cranial nerve (CN) function.1 The patient underwent staged surgeries. In the first stage, the tumor was partially excised with decompression of the trigeminal ganglion and nerve root in the lateral cavernous sinus wall, Meckel's cave. Postoperatively, MR angiography revealed worsening of the left ICA caliber. Therefore, a high-flow bypass from the external carotid artery to the middle cerebral artery (MCA) was performed with an anterior tibial artery graft. The patient recovered initially but developed enterococcus meningitis postoperatively, which was promptly identified and treated with antibiotics. At 1-yr follow-up, the graft was patent, and the patient had significant relief of his facial pain and cognitively improved.  This 2-dimensional video demonstrates the technique of partial excision of cavernous sinus meningioma with CN decompression, and the technique of a high-flow bypass from the external carotid artery to M2 MCA segment using an anterior tibial artery graft.  The patient gave informed consent for surgery and video recording. All relevant patient identifiers have been removed from the video and accompanying radiology slides.

Subtemporal, Transapical, and Transcavernous Approach to Clip Low-Lying Basilar Tip Aneurysm: 2-Dimensional Operative Video

Basilar tip aneurysm clipping is technically challenging because of the depth of operative corridor, rarity in presentation, and important perforators supplying deep, critical structures. Two major approaches to basilar tip aneurysms include (1) a frontotemporal (transorbital) trans-sylvian approach for most aneurysms and (2) a modified subtemporal approach for aneurysms with low-lying necks. A 53-yr-old woman presented to our institution with a large unruptured basilar tip aneurysm notable for a low, broad neck (6.4 mm). After discussion of risks and benefits of endovascular vs surgical options, the patient consented to operative intervention. She underwent a right frontotemporal craniotomy with zygomatic osteotomy, intradural petrous apicectomy, elective sectioning of the fourth cranial nerve (CN IV), and intracavernous removal of the dorsum sellae and posterior clinoid process to provide more space for aneurysm dissection. After temporary clipping of the basilar artery, the perforating arteries were dissected free from the aneurysm and the aneurysm occluded with 2 fenestrated clips. Important technical nuances of the approach include (1) achieving ample working room for temporary occlusion aneurysm dissection, (2) careful dissection of the perforators and contralateral P1, and (3) utilization of 2 fenestrated clips to accommodate and preserve the ipsilateral P1 segment. Postoperative angiogram showed complete aneur-ysmal occlusion. Postoperatively, the patient demonstrated mild cognitive impairment and a right CN IV palsy. At 6-wk follow-up, cognition recovered to normalcy. More recently, at 12-mo follow-up, the patient noted intermittent diplopia. Formal neuro-ophthalmologic assessment confirmed persistence of a CN IV palsy treated with prism lenses but no other neurological deficits.

The Future of Skull Base Surgery: A View Through Tinted Glasses

In the present report, we have broadly outlined the potential advances in the field of skull base surgery, which might occur within the next 20 years based on the many areas of current research in biology and technology. Many of these advances will also be broadly applicable to other areas of neurosurgery. We have grounded our predictions for future developments in an exploration of what patients and surgeons most desire as outcomes for care. We next examined the recent developments in the field and outlined several promising areas of future improvement in skull base surgery, per se, as well as identifying the new hospital support systems needed to accommodate these changes. These include, but are not limited to, advances in imaging, Raman spectroscopy and microscopy, 3-dimensional printing and rapid prototyping, master-slave and semiautonomous robots, artificial intelligence applications in all areas of medicine, telemedicine, and green technologies in hospitals. In addition, we have reviewed the therapeutic approaches using nanotechnology, genetic engineering, antitumor antibodies, and stem cell technologies to repair damage caused by traumatic injuries, tumors, and iatrogenic injuries to the brain and cranial nerves. Additionally, we have discussed the training requirements for future skull base surgeons and stressed the need for adaptability and change. However, the essential requirements for skull base surgeons will remain unchanged, including knowledge, attention to detail, technical skill, innovation, judgment, and compassion. We believe that active involvement in these rapidly evolving technologies will enable us to shape some of the future of our discipline to address the needs of both patients and our profession.

Developing microsurgical milestones for psychomotor skills in neurological surgery residents as an adjunct to operative training: the home microsurgery laboratory

OBJECTIVE

A variety of factors contribute to an increasingly challenging environment for neurological surgery residents to develop psychomotor skills in microsurgical technique solely from operative training. While adjunct training modalities such as cadaver dissection and surgical simulation are embraced and practiced at our institution, there are no formal educational milestones defined to help residents develop, measure, and advance their microsurgical psychomotor skills in a stepwise fashion when outside the hospital environment. The objective of this report is to describe an efficient and convenient "home microsurgery lab" (HML) assembled and tested by the authors with the goal of supporting a personalized stepwise advancement of microsurgical psychomotor skills.

METHODS

The authors reviewed the literature on previously published simulation practice models and designed adjunct learning modules utilizing the HML. Five milestones were developed for achieving proficiency with each graduated exercise, referencing the Accreditation Council for Graduate Medical Education (ACGME) guidelines. The HML setup was then piloted with 2 neurosurgical trainees.

RESULTS

The total cost for assembling the HML was approximately $850. Techniques for which training was provided included microinstrument handling, tissue dissection, suturing, and microanastomoses. Five designated competency levels were developed, and training exercises were proposed for each competency level.

CONCLUSIONS

The HML offers a unique, entirely home-based, affordable adjunct to the operative neurosurgical education mandated by the ACGME operative case logs, while respecting resident hospital-based education hours. The HML provides surgical simulation with specific milestones, which may improve confidence and the microsurgical psychomotor skills required to perform microsurgery, regardless of case type.

Microsurgical Resection of Recurrent Cavernous Sinus Hemangioma by Superior and Lateral Approach: 2-Dimensional Operative Video

This video shows the technical nuances of microsurgical resection of recurrent cavernous sinus (CS) hemangioma by superior and lateral approach.  A 77-yr-old woman presented with headache and difficulty in vision in right eye for 6 mo. She had previously undergone attempted resection of a right CS tumor in another hospital with partial removal, and the tumor had grown significantly. Neurological examination revealed proptosis, cranial nerve 3 palsy, and loss of vision in right eye (20/200). Left side visual acuity was 20/20.  Brain magnetic resonance imaging (MRI) demonstrated a large CS mass with homogeneous enhancement, measuring 3.3 × 3.3 × 2.6 cm, extending into the suprasellar cistern with mass effect on the right optic nerve. It extended anteriorly to the region of the right orbital apex and abuted the basilar artery posteriorly.  She underwent right frontotemporal craniotomy, posterolateral orbitotomy and anterior clinoidectomy as well as optic nerve decompression, and the CS tumor was removed by superior and lateral approach. An incision was made into the superior wall of the CS medial to the third nerve. On lateral aspect the tumor had extended outside the CS through the Parkinson's triangle. Posteriorly it extended through the clival dura. Anteriorly tumor encased the carotid artery and it was gradually dissected away. At the end of the operation, all of the cranial nerves were intact.  Postoperative MRI showed near complete tumor resection with preservation of the internal carotid artery. At 6 mo follow-up her modified Rankin Scale was 1 and vision in left eye was normal.  Informed consent was obtained from the patient prior to the surgery that included videotaping of the procedure and its distribution for educational purposes. All relevant patient identifiers have also been removed from the video and accompanying radiology slides.

Localization and Microsurgical Resection of Left Postcentral Gyrus Spetzler-Martin Grade 3 Arteriovenous Malformation by Intraoperative Neuronavigation and Tracing of Subcortical Draining Vein: 3-Dimensional Operative Video

This 42-yr-old man presented with a history of sudden right-sided facial and right arm weakness and dysarthria. Head computed tomography showed a left frontal-parietal blood clot. An intra-arterial digital subtraction angiography demonstrated a left subcortical postcentral, Spetzler-Martin Grade 3 arteriovenous malformation (AVM) with a diffuse nidus, measuring 2.1 × 1.5 cm, supplied by branches of the left MCA, and draining into a cortical vein and a deep vein, which was going toward the ventricle. Preoperative embolization was not possible.  The patient underwent left frontal-parietal craniotomy with intraoperative motor and sensory mapping. No arterialized veins were visible on the cortical surface. Neuronavigation localized the AVM in the subcortical postcentral gyrus. Through an incision in the postcentral sulcus, microdissection led to a yellowish gliotic plane. The large cortical vein was in the gliotic area and traced to the AVM. Circumferential microdissection was performed around the AVM. It had a very diffuse nidus; the arterial feeders were cauterized and divided, and the superior superficial and inferior deep draining veins were finally occluded, and AVM was removed.  Postoperative angiogram showed total removal of the AVM. At discharge, his right arm weakness had improved (power 5/5), and facial weakness and dysarthria were improving (modified Rankin Scale (mRS) 2). At 1-yr follow-up, facial weakness and dysarthria had improved considerably, and patient returned to work (mRS 1).  This video shows microsurgical resection of an AVM by neuronavigation and tracing of the subcortical draining vein. The technique of cauterizing the perforating arteries after temporary clipping with flow arrest is shown in the video. Informed consent was obtained from the patient prior to the surgery that included videotaping of the procedure and its distribution for educational purposes. All relevant patient identifiers have also been removed from the video and accompanying radiology slides.

Complete Microsurgical Resection of Large Retrochiasmatic Hypothalamic Craniopharyngioma by Transpetrosal Approach: 2-Dimensional Operative Video

This two-dimensional video shows the technical nuances of complete microsurgical resection of a hypothalamic craniopharyngioma located in the retrochiasmatic region by the transpetrosal approach.  This 49-yr-old man presented with progressive fatigue, excessive sleepiness, and difficulty in vision in both eyes. He was found to have right CN 3 paralysis and bitemporal hemianopsia on neurological examination. Further workup revealed panhypopituitarism. Brain magnetic resonance imaging (MRI) demonstrated a large solid retrochiasmatic hypothalamic lesion with homogeneous contrast enhancement, measuring 2.1 × 2.6 × 2.4 cm. Optic chiasm was prefixed, and the tumor was just posterior to the pituitary stalk area. The preoperative differential diagnosis included hypothalamic astrocytoma, craniopharyngioma, germinoma, and histiocytosis. Because of the prefixed chiasm, a presigmoid, transpetrosal approach was performed. Our initial plan was a large biopsy, but based on frozen section histology, we decided to excise the tumor completely. The tumor had a pseudocapsule, which was firm and yellowish. It was debulked, dissected from the surrounding hypothalamus, and removed completely. The pituitary stalk was found at the anterior and inferior ends of the tumor and was preserved.  Postoperatively, the patient developed diabetes insipidus and requires desmopressin replacement, which was gradually tapered. For panhypopituitarism, he is receiving thyroxine, hydrocortisone, and testosterone.  Postoperatively, patient had an improvement in vision in his left eye and ptosis was improving in the right eye with mRs 1- at 10-wk follow-up.  An informed consent was obtained from the patient prior to the surgery, which included videotaping of the procedure and its distribution for educational purposes. All relevant patient identifiers have also been removed from the video and accompanying radiology slides.

Bow Hunter's Syndrome: Complete Microsurgical Decompression of Vertebral Artery by Far Lateral Retrocondylar Approach: 3-Dimensional Operative Video

This 50-yr-old man had a 15-yr history of presyncopal episodes that were precipitated by turning his head to the right, and had worsened recently. Cerebral angiogram demonstrated complete cessation of anterograde flow in left vertebral artery (VA) at the level of the C1 sulcus arteriosus while turning head to right, indicating dynamic compression at the C1 level.  Patient underwent left extreme lateral retrocondylar approach, partial C1 laminectomy and opening of the C1 foramen with complete microsurgical decompression of the VA. After skin incision, meticulous muscle dissection was performed and superior and inferior oblique muscles were disconnected from the tubercle of C1. The VA was exposed, and three areas of constriction were visible, first at the atlanto-occipital membrane laterally; second, located more medially as the artery curved around the occipital condyle to enter the posterior fossa; and third, located anterior to C2 nerve root. The artery was dissected from all the surrounding tissues, preserving the C2 nerve root, and the Cl foramen was opened completely. The Cl lamina was also partially resected and grooved to allow free placement of the VA. The VA was also decompressed near the C2 foramen. Postoperative computed tomography angiogram of the head and neck showed complete decompression of VA. The patient had no episodes of presyncope or dizziness while turning head to right and his mRs was 0 at 8 mo follow up.  This 3D video shows the technical nuances of decompression of V3 segment of VA in bow hunters's syndrome.  Informed consent was obtained from the patient prior to the surgery that included videotaping of the procedure and its distribution for educational purposes. All relevant patient identifiers have also been removed from the video and accompanying radiology slides.

Cranial Chordoma: A New Preoperative Grading System

BACKGROUND

Chordomas are rare but challenging neoplasms involving the skull base. A preoperative grading system will be useful to identify both areas for treatment and risk factors, and correlate to the degree of resection, complications, and recurrence.

OBJECTIVE

To propose a new grading system for cranial chordomas designed by the senior author. Its purpose is to enable comparison of different tumors with a similar pathology to clivus chordoma, and statistically correlate with postoperative outcomes.

METHODS

The numerical grading system included tumor size, site of the tumor, vascular encasement, intradural extension, brainstem invasion, and recurrence of the tumor either after surgery or radiotherapy with a range of 2 to 25 points; it was used in 42 patients with cranial chordoma. The grading system was correlated with number of operations for resection, degree of resection, number and type of complications, recurrence, and survival.

RESULTS

We found 3 groups: low-risk 0 to 7 points, intermediate-risk 8 to 12 points, and high-risk ≥13 points in the grading system. The 3 groups were correlated with the following: extent of resection (partial, subtotal, or complete; P < .002); number of operative stages to achieve removal (P < .014); tumor recurrence (P = .03); postoperative Karnofsky Performance Status (P < .001); and with successful outcome (P = .005). The grading system itself correlated with the outcome (P = .005).

CONCLUSION

The proposed chordoma grading system can help surgeons to predict the difficulty of the case and know which areas of the skull base will need attention to plan further therapy.

Targeted Embolization of Aneurysms Associated With Brain Arteriovenous Malformations at High Risk for Surgical Resection: A Case-Control Study

BACKGROUND

High-risk components of brain arteriovenous malformations (BAVMs) can be targeted to reduce the risk of lesion rupture.

OBJECTIVE

To evaluate targeted embolization of aneurysms against other means of treatment with a case-control analysis; we previously investigated this approach associated with BAVMs.

METHODS

Retrospective analysis of patients with BAVMs was performed, identifying patients treated with intention to occlude only an aneurysm associated with a BAVM. For each targeted aneurysm embolization (TAE) patient identified, 4 control patients were randomly selected, controlling for rupture status, age, and Spetzler-Martin plus Lawton-Young supplemental score. Analysis was performed to compare rates of adverse events (hemorrhage, new seizure, and death) between the 2 groups.

RESULTS

Thirty-two patients met inclusion criteria, and 128 control patients were identified, out of 1103 patients treated during the study period. Thirty-four adverse events occurred (15 ruptures, 15 new seizures, and 11 deaths) during the follow-up period (mean 1157 d for the TAE cohort and 1036 d for the non-TAE cohort). Statistically lower associations were noted for the TAE group for any adverse event (hazard ratio 0.28, P = .037) and the composite outcome of hemorrhage or new seizure (hazard ratio 0.20, P = .029).

CONCLUSION

For BAVMs at high risk for surgical resection, TAE can be performed safely and effectively. Patients treated with TAE had better outcomes than matched patients undergoing other combinations of treatment. TAE can be considered for BAVMs with high operative risk prior to radiosurgery or when no other treatment options are available.

Sternocleidomastoid Encephalomyosynangiosis for Treatment-Resistant Moyamoya Disease

BACKGROUND AND IMPORTANCE

Refractory ischemic symptoms in moyamoya disease are a challenging problem, particularly in situations in which multiple direct and indirect revascularization techniques have already been employed. In addition, revascularization of the parietal lobes is difficult, as this area is a watershed between the middle cerebral artery and posterior cerebral artery distributions.

CLINICAL PRESENTATION

This is the case of a 50-yr-old woman with hemibody sensorimotor deficits, who had previously undergone bilateral arterial bypass and temporalis myosynangiosis. A method for indirect surgical cerebral revascularization is described, utilizing a rotated and tunneled sternocleidomastoid flap. The perfused muscle is approximated to the cortical surface, with adjacent sulci dissected to expose the underlying vasculature. After sternocleidomastoid encephalomyosynangiosis, the patient experienced symptomatic improvement, along with the appearance of new pial collateral vasculature on diagnostic cerebral angiography. Pre- and postoperative dynamic perfusion computed tomography with acetazolamide challenge demonstrate an increase in cerebral blood flow and decrease in mean transit time, as well as improved cerebrovascular reserve.

CONCLUSION

Sternocleidomastoid encephalomyosynangiosis using a tunneled muscle flap is a useful method for revascularization of the parietal and occipital lobes, particularly for refractory moyamoya in cases where a variety of other options have been exhausted.

Clinical outcomes and cost-effectiveness analysis for the treatment of basilar tip aneurysms

Background

Endovascular treatment of basilar tip aneurysms is less invasive than microsurgical clipping, but requires closer follow-up.

Objective

To characterize the additional costs associated with endovascular treatment of basilar tip aneurysms rather than microsurgical clipping.

Materials and methods

We obtained clinical records and billing information for 141 basilar tip aneurysms treated with clip ligation (n=48) or endovascular embolization (n=93). Costs included direct and indirect costs associated with index hospitalization, as well as re-treatments, follow-up visits, imaging studies, rehabilitation, and disability. Effectiveness of treatment was quantified by converting functional outcomes (modified Rankin Scale (mRS) score) into quality-adjusted life-years (QALYs). Cost-effectiveness was performed using cost/QALY ratios.

Results

Average index hospitalization costs were significantly higher for patients with unruptured aneurysms treated with clip ligation ($71 400 ± $47 100) compared with coil embolization ($33 500 ± $22 600), balloon-assisted coiling ($26 200 ± $11 600), and stent-assisted coiling ($38 500 ± $20 900). Multivariate predictors for higher index hospitalization cost included vasospasm requiring endovascular intervention, placement of a ventriculoperitoneal shunt, longer length of stay, larger aneurysm neck and width, higher Hunt-Hess grade, and treatment-associated complications. At 1 year, endovascular treatment was associated with lower cost/QALY than clip ligation in unruptured aneurysms ($52 000/QALY vs $137 000/QALY, respectively, p=0.006), but comparable rates in ruptured aneurysms ($193 000/QALY vs $233 000/QALY, p=0.277). Multivariate predictors for higher cost/QALY included worse mRS score at discharge, procedural complications, and larger aneurysm width.

Conclusions

Coil embolization of basilar tip aneurysms is associated with a lower cost/QALY. This effect is sustained during follow-up. Clinical condition at discharge is the most significant predictor of overall cost/QALY at 1 year.

Microsurgical Clipping of a Ruptured Basilar Apex Aneurysm: 3-Dimensional Operative Video

A 59-yr-old woman presented with a sudden onset of headache with neck pain and stiffness, Hunt and Hess grade 2. Brain computed tomography (CT) showed subarachnoid hemorrhage, Fisher Grade 2. Intra-arterial digital subtraction angiography (IADSA) showed a basilar artery apex aneurysm, dome size 9 mm and neck 3 mm, leaning towards the right, and a dominant right artery of Percheron. Endovascular treatment and microsurgical clipping were both explained to the patient, but she decided to undergo microsurgery due to the durability of treatment. She underwent a right frontotemporal craniotomy and orbital osteotomy. We performed optic nerve decompression and intradural anterior clinoidectomy to enhance the exposure. Working through the carotid-oculomotor space, the posterior communicating artery was traced back to the posterior cerebral artery. The basilar artery was temporarily occluded for aneurysm dissection after burst suppression to protect the brain. The aneurysm was irregular, multilobulated, and projecting upward. The dominant thalamoperforate artery (artery of Percheron) was arising from the right P1, and densely adherent to the sac of the aneurysm. After dissection of the artery of Percheron away from the aneurysm, it was completely occluded by a side-curved titanium clip. The patient had right oculomotor nerve paresis and headache postoperatively, but at discharge 2 wk later the headache and paresis had completely resolved. The postoperative IADSA showed total occlusion of the aneurysm with patency of the artery of Percheron. This 3-dimensional video shows the technical nuances of microsurgical clipping of a ruptured basilar apex aneurysm and intraoperative dissection of the artery of Percheron. Informed consent was obtained from the patient prior to the surgery that included videotaping of the procedure and its distribution for educational purposes. All relevant patient identifiers have also been removed from the video and accompanying radiology slides.

Microsurgical and Endoscope Assisted Resection of a Right Intracanalicular Vestibular Schwannoma Two-Dimensional Operative Video

A 36-year-old lady presented with tinnitus and hearing loss for 1 year which was progressively worsening. A hearing test revealed pure tone average (PTA) between 48 to 65 dB and speech discrimination of 56% at 95 dB. Brain magnetic resonance imaging (MRI) showed a right vestibular schwannoma 5 × 8 mm ( Fig. 1 ) which extended far laterally to the fundus of internal auditory canal (IAC). A translabyrinthine approach was suggested by another neurosurgeon/neurotologist team, but the patient decided to undergo operation by retrosigmoid approach with attempted hearing preservation. She underwent a right retrosigmoid craniotomy, craniectomy, and mastoidectomy with far lateral approach. We performed petrous transcanalicular microsurgical approach with the assistance of neuroendoscope. Intraoperatively, the internal auditory artery was looping into the IAC between cranial nerves VII and VIII, and coming out inferiorly. The IAC was opened by the diamond drill, ultrasonic bone curette, and fine rongeurs. The tumor was grayish in color with filling the lateral aspect of the IAC. After circumferential dissection of the tumor capsule, the tumor was removed completely. It was arising from the inferior vestibular nerve which was stretched. The patient had vertigo and nausea postoperatively but it is steadily improving. Her hearing test has improved to a PTA of 22 dB and speech discrimination of 100% at 70 dB at 6 weeks. The postoperative MRI showed total resection. This two-dimensional video shows the technical nuances of microsurgical retrosigmoid approach and endoscopic assisted resection of an intracanalicular vestibular schwannoma and the value of attempting hearing preservation in all vestibular schwannomas ( Fig. 2 ). The link to the video can be found at: https://youtu.be/KHrO_iDI2tw .

Retrosigmoid Craniotomy for the Removal of Left Sided Tentorial and Posterior Fossa Meningioma Combined with Microvascular Decompression for Hemifacial Spasm

This 68-year-old woman presented with repeated episodes of bilateral hemifacial spasm with headache for 5 years and with recent progression of left sided symptoms. Preoperative imaging showed a left sided tentorial meningioma with brain stem and cerebellar compression. Left facial nerve was compressed by the vertebral artery (VA) and the right facial nerve by the anterior inferior cerebellar artery (AICA). This patient underwent left side retrosigmoid craniotomy and mastoidectomy. The cisterna magna was drained to relax the brain. The tumor was very firm, attached to the tentorium and had medial and lateral lobules. The superior cerebellar artery was adherent to the lateral lobule of the tumor and dissected away. The tumor was detached from its tentorial base; we first removed the lateral lobule. Following this, the medial lobule was also completely dissected and removed. The root exit zone of cranial nerve (CN) VII was dissected and exposed. The compression was caused both by a prominent VA and AICA. Initially, the several pieces of Teflon felt were placed for the decompression. Then vertebropexy was performed by using 8–0 nylon suture placed through the VA media to the clival dura. A further piece of Teflon felt was placed between cerebellopontine angle region and AICA. Her hemifacial spasm resolved postoperatively, and she discharged home 1 week later. Postoperative imaging showed complete tumor removal and decompression of left CN VII. This video shows the complex surgery of microsurgical resection of a large tentorial meningioma and microvascular decompression with a vertebropexy procedure.

The link to the video can be found at: https://youtu.be/N5aHN9CRJeM .

Predictors of Recurrence, Progression, and Retreatment in Basilar Tip Aneurysms: A Location-Controlled Analysis

BACKGROUND

Endovascular treatment of intracranial aneurysms is associated with higher rates of recurrence and retreatment, though contemporary rates and risk factors for basilar tip aneurysms (BTAs) are less well-described.

OBJECTIVE

To characterize progression, retreatement, and retreated progression of BTAs treated with microsurgical or endovascular interventions.

METHODS

We retrospectively reviewed records for 141 consecutive BTA patients. We included 158 anterior communicating artery (ACoA) and 118 middle cerebral artery (MCA) aneurysms as controls. Univariate and multivariate analyses were used to calculate rates of progression (recurrence of previously obliterated aneurysms and progression of known residual aneurysm dome or neck), retreatment, and retreated progression. Kaplan-Meier analysis was used to characterize 24-mo event rates for primary outcome prediction.

RESULTS

Of 141 BTA patients, 62.4% were ruptured and 37.6% were unruptured. Average radiographical follow-up was 33 mo. Among ruptured aneurysms treated with clipping, there were 2 rehemorrhages due to recurrence (6.1%), and none in any other cohorts. Overall rates of progression (28.9%), retreatment (28.9%), and retreated progression (24.7%) were not significantly different between surgical and endovascular subgroups, though ruptured aneurysms had higher event rates. Multivariate modeling confirmed rupture status (P = .003, hazard ratio = 0.14) and aneurysm dome width (P = .005, hazard ratio = 1.23) as independent predictors of progression requiring retreatment. In a separate multivariate analysis with ACoA and MCA aneurysms, basilar tip location was an independent predictor of progression, retreatment, and retreated progression.

CONCLUSION

BTAs have higher rates of progression and retreated progression than other aneurysm locations, independent of treatment modality. Rupture status and dome width are risk factors for progression requiring retreatment.

Microsurgical Excision of T12-L1 Pial Arteriovenous Malformation: 3-Dimensional Operative Video

This 29-yr-old man presented with progressive paraparesis, sensory loss, allodynia, bowel, and bladder dysfunction for 9 mo, acutely exacerbated in the preceding 24 h. Magnetic resonance imaging scan showed multiple dilated vessels involving the thoracic cord. Spinal angiogram revealed a T12-L1 pial arteriovenous malformation (AVM)/arteriovenous fistula on the left side. It was fed by an L1 radicular artery that filled the anterior spinal artery, which in turn had multiple feeders to a pial AVM. Because of the supply from the anterior spinal artery with multiple feeders to the AVM, and the danger of infarction of the conus, embolization was not performed. He underwent T11-L1 laminectomy laterally to the pedicles and excision of AVM. There was one large arterialized vein in the midline that had a fistulous connection with an artery coursing up from inferiorly. Despite occlusion of this fistula, the vein was still arterialized. On further exploration, there was a large artery coming in to the subarachnoid space at the T11 level and coursing inferiorly, and entering the intradural pial AVM with a glomus of vessels located at the T12 level in the left anterolateral subpial aspect of the cord. This major artery as well as multiple smaller vessels going into it were cauterized and divided, and the AVM was totally excised. Postoperative angiogram showed complete excision of the nidus. At 1 mo follow-up, he had complete recovery of motor and bladder functions but bowel dysfunction persisted. He was independent for his daily activities. Informed consent was obtained from the patient prior to the surgery that included videotaping of the procedure and its distribution for educational purposes. All relevant patient identifiers have also been removed from the video and accompanying radiology slides.

Left External Carotid Artery to the Middle Cerebral Artery Bypass with Radial Artery Graft and Clip Reconstruction of a Large Middle Cerebral Artery Fusiform Aneurysm: 3-Dimensional Operative Video

This 16-yr-old boy presented with episodes of severe headaches, blurred vision, dizziness, and muffled hearing and was discovered to have a large fusiform aneurysm of the left middle cerebral artery (MCA), M1 segment, 20 × 12 mm in dimension. The lenticulostriate arteries were arising proximal and distal to the aneurysm, but the anterior temporal artery was arising from the aneurysm. The aneurysm culminated in the distal M1 segment, and M1 immediately branched into 3 M2 vessels, the lower one being the larger. Due to origin of the lenticulostriate arteries and the anterior temporal artery and patient's age, a bypass was preferred to a flow diversion stent.

 He underwent left frontotemporal craniotomy and orbital osteotomy, left cervical external carotid artery exposure followed by radial artery graft extraction. The Sylvian fissure was opened and intracranial ICA was exposed for proximal control. The distal M2 vessels traced back toward the aneurysm. The aneurysm was not clippable and a bypass to the larger inferior M2 branch was performed followed by aneurysm trapping. The radial artery graft bypass was placed from the left external carotid artery to the M2 segment of left MCA, followed by clip reconstruction and occlusion of the MCA aneurysm with the preservation of the anterior temporal branch and the lenticulostriate vessels. The patient had no postoperative complications. At the follow-up, one month after surgery, he was doing well, and his angiogram demonstrated patency of the bypass.

 This video shows the management of a complex fusiform M1 aneurysm with bypass and trapping.

 Informed consent was obtained from the patient prior to the surgery that included videotaping of the procedure and its distribution for educational purposes. All relevant patient identifiers have also been removed from the video and accompanying radiology slides.

Microsurgical Resection of Ruptured Large Left Temporo-Occipital Arteriovenous Malformation: 3-Dimensional Operative Video

A 59-yr-old man presented with intraventricular hemorrhage and was found to have a large temporo-occipital arteriovenous malformation (AVM), Spetzler-Martin grade 4. The preoperative intra-arterial digital subtraction angiography (IADSA) showed the AVM was 4 × 4 cm2, had superficial and deep venous drainage, and was fed by multiple branches of the posterior cerebral artery and middle cerebral artery. Preoperative embolization was done in 4 stages. He underwent a left temporo-occipital craniotomy, mastoidectomy, and retrosigmoid craniotomy with a posterior temporal approach. Intraoperatively, there was a large draining vein draining into the sigmoid sinus in the location of the vein of Labbe, and multiple other feeding arteries and draining veins, including periventricular vessels. Circumferential dissection of the AVM was done from posteriorly, superiorly, anteriorly, and then inferiorly. The technique of temporary clipping and cauterizing the perforating arteries, and then sectioning them after flow arrest is shown in the video. Large arterial feeders were cauterized and divided. Three permanent aneurysm clips were left to control bleeding from the vessels of the trigone of the lateral ventricle. After the large draining vein into the sigmoid sinus was occluded, the AVM was completely removed. The patient had acute nonfluent aphasia postoperatively but improved after speech therapy. The postoperative IADSA demonstrated total resection. At 3-mo follow-up, he had recovered completely (mRS0). This 3-D video shows the technical nuances of microsurgical resection of a complex large AVM. Informed consent was obtained from the patient prior to the surgery that included videotaping of the procedure and its distribution for educational purposes. All relevant patient identifiers have also been removed from the video and accompanying radiology slides.

Brain Stem Cavernous Malformations: Operative Nuances of a Less-Invasive Resection Technique

BACKGROUND

Different operative techniques are reported for the resection of brainstem cavernous malformations (BSCMs). The senior author has previously reported on a less-invasive technique of entering the brain stem with piecemeal removal of BSCMs, especially the deep-seated ones.

OBJECTIVE

To present a larger series of these lesions, emphasizing the approach to the brain stem via case selection. We discuss the nuances of the less-invasive operative technique through case illustrations and intraoperative videos.

METHODS

A retrospective review of 46 consecutive cases of BSCMs, with their clinical and radiographic data, was performed. Nine cases were selected to illustrate 7 different operative approaches, and discuss surgical nuances of the less-invasive technique unique to each.

RESULTS

Postoperative morbidity, defined as an increase in modified Rankin Scale, was observed in 5 patients (10.9%). A residual BSCM was present in 2 patients (4.3%); both underwent reoperation to remove the remainder. At follow-up of 31.1 ± 27.8 mo, 3 patients experienced recurrence (6.5%). Overall, 65% of our patients improved, 20% stayed the same, and 11% worsened postsurgery. Two patients died, yielding a mortality of 4.3%.

CONCLUSION

Using the less-invasive resection technique for piecemeal BSCM removal, in appropriately selected patients, has yielded comparable to improved patient outcomes over existing large series. In our experience, lateral, anterolateral, and posterolateral approaches are favorable over direct midline (dorsal or ventral) approaches. A thorough understanding of brain-stem safe-entry zones, in conjunction with appropriate approach selection, is key to a good outcome in challenging cases.