Faculty Bibliography

OBJECTIVE:Minimally invasive alternatives to the pterional craniotomy include the minipterional and the supraorbital craniotomy (SOC). The latter is performed via either an eyebrow or an eyelid skin incision. The purpose of this systematic review was to analyze the type and the incidence of approach-related complications of these keyhole craniotomies. METHODS:We review pertinent publications retrieved by search in the PubMed/Medline database. Inclusion criteria were all full-text publications, abstracts, and posters in English, up to 2016, reporting clinical results. RESULTS:105 publications containing data on 5837 surgeries performed via a minipterional or either of the two variants of the SOC met the eligibility criteria. Pain on mastication was the most commonly reported approach-related complication of the minipterional approach, where it occurred in 7.5% of cases. Temporary palsy of the frontal branch of the facial nerve and temporary supraorbital hypesthesia were associated with the SOC eyebrow variant, where it occurred in 6.5%, respectively in 4.6% of cases. Transient postoperative periorbital edema and transient ophthalmoparesis occurred in 36.8%, respectively in 17.4% of cases when the SOC was performed via an eyelid skin incision. The risk of occurrence of the latter two approach-related complications was related to the removal of the orbital rim, which is obligate part of the SOC through the eyelid approach but optional with the SOC eyebrow variant. CONCLUSION/CONCLUSIONS:Each of three "keyhole" approaches has a specific set and incidence of approach-related complications. It is essential to be aware of these complications to make the safest individual choice.

Endovascular and surgical techniques are conventional options for treating intracranial aneurysms, but criteria for selecting an optimal approach for individual patients remain variable across practitioners and institutions. While endovascular and surgical approaches are generally used alone, both modalities combined in single patients can produce efficacious outcomes. The aim of this study was to evaluate outcomes of combined, concomitant endovascular and surgical modalities in the treatment of multiple and/or complex aneurysms in single patients. Indications, sequencing rationale, and categorization for multimodality treatments are reviewed. All intracranial aneurysms treated at our institution from 2004 to 2014 were reviewed. Single patients who had undergone concomitant endovascular and surgical treatments were eligible for participation in our study. Demographic data and clinical presentation parameters, including location, size, and morphological features of lesions, treatment sequencing, and outcomes were recorded. Our cohort consisted of 27 patients with 57 aneurysms who received concomitant endovascular and surgical treatment of their aneurysm(s). One patient arrived to us after he had an aneurysm clipped at an outside institution and then required treatment for a contralateral ruptured aneurysm. 66.7% of patients were diagnosed with subarachnoid hemorrhage. These were subdivided according to therapeutic approach: clipping and coiling (CL+CO), clipping and stenting (CL+ST), bypass and endovascular parent vessel occlusion (PVO) (BY+PVO), attempted clipping then stenting, and bypass followed by stenting. Glasgow Outcome Scale was as follows: CL-CO-Multiple, 4.17 (five in unruptured patients, 3.75 in ruptured); CO-CL-Multiple, five (all patients had a ruptured aneurysm); CL-CO-Single, three (all patients had a ruptured aneurysm); CO-CL-Single, five (all patients had a ruptured aneurysm). No patients suffered a new neurological deficit as a result of treatment. A total of two mortalities were documented. Concomitant, mutimodality endovascular and surgical therapy may offer a safe and potentially more effective paradigm than single modality approaches for the management of multiple, complex, or "failed" aneurysm treatments in selected patients.

We describe a patient who presented with superior quadrianopsia due to an occipital micro AVM that bled into the optic radiation. Onyx embolization was attempted. However, early follow-up angiogram revealed recanalization and recurrence of the AVM. He was then taken to the hybrid operative room, where a complete resection was achieved confirmed by intraoperative angiogram. He made a complete recovery with no new neurologic deficit and stable visual field deficit. This case demonstrates treatment strategy, surgical planning, and technical nuances in microsurgical resection of micro AVMs located in an eloquent area. Management of a ruptured microarteriovenous malformation (microAVM) localized in an eloquent brain region is challenging. The major difficulties are those related to localizing and defining the micronidus in order to achieve complete resection and definitive cure while preserving function. The best and definitive treatment for AVMs is either surgical resection or radiosurgery. However, in our institute a small subset of microAVMs might be cured by endovascular embolization in a single session. In the case presented here, a single feeder was demonstrated and microcatheter navigation toward a good working position seemed feasible; thus we decided to try first an endovascular approach.

BACKGROUND: Intraoperative angiography is routinely utilized for aneurysms and arteriovenous malformations (AVMs) to verify complete occlusion and resection. Surgery for spinal and posterior fossa neurovascular lesions is usually performed in prone position. Intraoperative angiography in the prone position is challenging and there is no standardized protocol for this procedure. OBJECTIVE: To describe our experience with intraoperative angiography in the prone and lateral positions, using upper extremity arterial access. METHODS: We reviewed our experience with intraoperative angiography in the prone position between 2014 and 2015, where vascular access was obtained via the upper extremity arteries. Patients were treated in a hybrid endovascular operating room. High cervical and intracranial lesions were studied via brachial or radial access. All accesses were obtained using ultrasonographic guidance and a small caliber arterial sheath (4F). RESULTS: Five patients were treated in the prone and lateral positions using brachial/radial artery access. Patients harbored cerebellar AVM, lateral medullary AVM, cervical arteriovenous fistula (AVF), tentorial dural AVF, and tentorial-incisural dural AVF. Patients were positioned prone (n = 2), semiprone (n = 2), and lateral (n = 1) for the surgery. Three patients were treated via right brachial artery access. Two patients were treated via radial arteries access. All patients tolerated the procedures without technical or clinical complications. Intraoperative angiography verified complete occlusion and resection in all cases prior to surgical closure. CONCLUSIONS: Intraoperative angiography in the prone and lateral positions using upper extremity access is an important adjunct. Brachial or radial access can be obtained safely and provides comfortable and quick approaches.

OBJECTIVE The Pipeline Embolization Device (PED) is now a well-established option for the treatment of giant or complex aneurysms, especially those arising from the anterior circulation. Considering the purpose of such treatment is to maintain patency of the parent vessel, postembolization occlusion of the parent artery can be regarded as an untoward outcome. Antiplatelet therapy in the posttreatment period is therefore required to minimize such events. Here, the authors present a series of patients with anterior circulation aneurysms treated with the PED who subsequently experienced parent vessel occlusion (PVO). METHODS The authors performed a retrospective review of all anterior circulation aneurysms consecutively treated at a single institution with the PED through 2014, identifying those with PVO on follow-up imaging. Aneurysm size and location, number of PEDs used, and follow-up digital subtraction angiography results were recorded. When available, pre- and postembolization platelet function testing results were also recorded. RESULTS Among 256 patients with anterior circulation aneurysms treated with the PED, the authors identified 8 who developed PVO after embolization. The mean aneurysm size in this cohort was 22.3 mm, and the number of PEDs used per case ranged from 2 to 10. Six patients were found to have asymptomatic PVO discovered incidentally on routine follow-up imaging between 6 months and 3 years postembolization, 3 of whom had documented "delayed" PVO with prior postembolization angiograms confirming aneurysm occlusion and a patent parent vessel at an earlier time. Two additional patients experienced symptomatic PVO, one of which was associated with early discontinuation of antiplatelet therapy. CONCLUSIONS In this large series of anterior circulation aneurysms, the authors report a low incidence of symptomatic PVO, complicating premature discontinuation of postembolization antiplatelet or anticoagulation therapy. Beyond the subacute period, asymptomatic PVO was more common, particularly among complex fusiform or very large-necked aneurysms, highlighting an important phenomenon with the use of PED for the treatment of anterior circulation aneurysms, and suggesting that extended periods of antiplatelet coverage may be required in select complex aneurysms.

BACKGROUND: Conventional craniotomy approaches involve substantial soft tissue manipulation that can cause complications. The transciliary supraorbital keyhole approach was developed to avoid these complications. OBJECTIVE: To review the safety and effectiveness of the transciliary supraorbital keyhole approach. MATERIAL AND METHODS: We searched the PubMed/Medline database for full-text publications from 1996 onward containing data on 100 or more cases of aneurysm clipping or tumor resection by the transciliary supraorbital approach. The primary outcome was the incidence of approach-related complications. The secondary outcomes were the aneurysm occlusion rate and the extent of tumor resection. RESULTS: Eight publications met the eligibility criteria. All publications were of the retrospective case-series or case-cohort type without any independent assessment of outcomes. The risk of bias at the individual study level may thus have influenced any conclusions drawn from the overall study population, which included 2783 patients with 3085 lesions (2508 aneurysms and 577 tumors). Approach-related complications included 3.3% CSF collection or CSF leak, 4.3% permanent and 1.6% temporary supraorbital hypesthesia, 2.9% permanent and 1% temporary facial nerve palsy, and 1% wound healing disturbance/infection. Complete aneurysm clipping was achieved in 97% of cases, and complete tumor resection in 90% of cases. The overall surgical revision rate was 2.5%. The esthetic outcome was typically reported as highly acceptable. CONCLUSIONS: This approach may represent a safe, effective, and less invasive alternative to conventional craniotomy in experienced hands and for a well-selected subset of patients. However, higher-level evidence is needed to confirm this hypothesis.

Aneurysms of the anterior cerebral artery (ACA) located distal to the anterior communicating artery complex (ACOM) remain challenging to treat with surgical clip reconstruction as well as with endovascular coil-embolization strategies. We have treated five complex geometry distal ACA aneurysms with endoluminal reconstruction using the Pipeline Embolization Device (PED). Two aneurysms were of the dysplastic fusiform type. Three aneurysms were of complex saccular configuration. Three aneurysms were treated electively at the outset with PED. One patient had previously undergone aborted clip reconstruction, and one was treated for recurrent aneurysm growth after coil embolization. The mean diameter of the ACA in this cohort was 1.96mm proximal to the aneurysm and 1.79mm distal to the aneurysmal segment. A single PED of 2.5mm inner diameter was the sole treatment in four cases. Two PEDs, telescopically overlapped across the aneurysm, were used in the remaining case. All devices were deployed successfully. No parent artery occlusion or stenosis was observed. In all cases an associated branch vessel arising from the vicinity of the aneurysm or incorporated into its neck was covered by the endoluminal construct. At follow-up angiography, robust antegrade flow was maintained in the jailed branch. One patient experienced asymptomatic, delayed occlusion of the jailed branch. Complete aneurysm occlusion was seen in all patients. We confirm that PED can be deployed in parent vessels smaller than 2mm diameter, and that endoluminal reconstruction with the PED may be a safe and effective treatment alternative for selected distal ACA aneurysms.

BACKGROUND:In the past, microsurgical bypass was the best option for revascularization of cerebrovascular lesions that required flow replacement or flow augmentation. Over the last 2 decades with advancements in the field of neuroendovascular surgery, especially with the revolution of flow diverting stents as well as the results of the Carotid Occlusion Surgery Study, indications for microvascular bypass have significantly decreased. The purpose of this study was to evaluate trends in cerebral revascularization over the past 8 years. METHODS:We retrospectively reviewed patients with cerebral revascularization surgery during the years 2006-2014 in a single surgeon's practice. All patients who had undergone cerebral revascularization for any indication were included in the study. RESULTS:We identified 106 patients who had undergone cerebral bypass; 2 patients were excluded. Of 104 patients, 60% were female and 40% were male. Indications for surgery were giant aneurysm in 48 patients, arterial occlusion in 30 patients, and moyamoya disease in 26 patients. In all indications except for moyamoya disease, case number per year declined. A marked decrease was noted in revascularization for treatment of giant aneurysm or occlusion. CONCLUSIONS:This study demonstrates the impact that both scientific inquiry and technologic advances have had on a challenging and valuable technique in cerebrovascular surgery. Indications for both flow replacement and augmentative bypass remain. However, the marked decline in indications may have an indelible impact on maintenance of surgical proficiency as well as the ability for young neurosurgeons to develop this valuable skill set.

OBJECTIVE:Surgical resection of posterior fossa metastases (PFM) includes either suboccipital craniotomy or suboccipital craniectomy. The optimal surgical technique is yet to be defined. We examined the association between the chosen surgical approach and the occurrence of postoperative complications. METHODS:We retrospectively evaluated medical records and imaging characteristics of patients who underwent resection of newly diagnosed PFM between 2003 and 2014 in our medical center to identify covariates that significantly affected postoperative complications. RESULTS:Of 917 patients with brain metastases, 88 patients underwent surgery for PFM and were included in the study. Craniectomy was performed in 54 cases (61%). Urgent postoperative posterior fossa decompression or cerebrospinal fluid diversion was performed in 4 patients (4.5%). Postoperative complications included postoperative central nervous system infection (n = 10 [12%]), cerebrospinal fluid leak (n = 3 [4%]), wound dehiscence (n = 6 [7%]), and long-term pseudomeningocele (n = 12 [14%]). The perioperative mortality rate was 2.3% (n = 2). Multivariate analysis that included patient baseline characteristics, imaging study parameters, and surgical approaches demonstrated that suboccipital craniectomy was associated with more postoperative complications (P = 0.03, odds ratio = 4.48, 95% confidence interval = 1.14-17.6). There was no correlation between patient baseline characteristics or surgical technique with the need for urgent postoperative posterior fossa decompression or cerebrospinal fluid diversion. CONCLUSIONS:Suboccipital craniotomy may be associated with a lower incidence of postoperative morbidity compared with suboccipital craniectomy and should be considered as the preferred approach for the resection of PFM.