Faculty Bibliography

BACKGROUND: Treatment of selected wide-neck internal carotid artery (ICA) bifurcation aneurysms remains challenging for clip reconstruction and for endovascular options. OBJECTIVE: To describe a new endovascular treatment technique for wide-neck ICA bifurcation (ICAb) aneurysms. METHODS: We have employed a treatment approach that uses both complete proximal occlusion and reversal of flow in the ipsilateral A1 segment, using different endovascular modalities such as coils, stent-assisted coiling, or flow diverters (FDs) plus coiling concomitantly. This endovascular technique may overcome the challenges of current treatments and high recanalization rates for coiled ICAb aneurysms. RESULTS: We treated four patients in whom we redirected the pre-existing flow in the supraclinoid ICA into the ipsilateral A1 and M1 segments, to a new unilateral, linear flow from the supraclinoid ICA solely into the ipsilateral M1 segment. This resulted in the establishment of flow from the contralateral A1 segment into the ipsilateral A1 segment, allowing supply of only demanding perforating arteries on this specific (ipsilateral) segment. This technique was not associated with any new neurological deficits or radiographic ischemia. The four patients reviewed were all treated using coils. One was treated with a standard stent. The other two were treated with a FD. CONCLUSIONS: We found that the proposed technique of flow modification can allow for hemodynamic conversion of ICAb to 'side-wall' aneurysm. In patients with good collateral flow through the anterior communicating complex, this treatment paradigm is safe and effective.

OBJECT The use of the Pipeline Embolization Device (PED) as a sole endovascular modality has been described for the treatment of brain aneurysms. The benefit of using coils concurrently with a limited number of PEDs is not well documented. The authors describe their experience with this technique as well as their midterm clinical and angiographic results. METHODS This is a retrospective review of patients treated between 2011 and 2014. The authors placed a minimal number of PEDs with the addition of coils using a "jailed" microcatheter technique. A partially dense coil mass was obtained. Immediate and midterm clinical and angiographic results are reviewed. RESULTS The authors treated 27 patients harboring 28 aneurysms using this technique. The mean aneurysm size was 11.9 mm, and the mean neck size was 5.4 mm. A mean of 1.48 PEDs were placed per patient, and a mean of 1.33 PEDs per aneurysm were placed. The Raymond score immediately after PED placement was 2 or 3 in 82.1% of the patients. There were no intraprocedural or postprocedural complications. All PEDs were successfully deployed. No clinical or technical adverse effects related to the coil mass were observed. There were no clinical or radiographic signs of ischemia in this group. At follow-up imaging, complete aneurysm occlusion was demonstrated on the first MR angiogram (3-5 months) in all patients who reached this milestone. Follow-up digital subtraction angiography (5-13 months) confirmed complete occlusion in all patients who reached this milestone. All patients maintained their baseline clinical status. CONCLUSIONS The deployment of PEDs with concurrent partially dense coiling is safe and efficacious. This technique achieved early complete occlusion and endovascular reconstruction of the parent vessel, without inducing mass effect. Favorable midterm clinical results were observed in all patients.

The differential diagnosis of a brain lesion with two discordant pathology reports includes the presence of collision tumor, metaplastic changes, and labeling errors that occurred during the processing of the specimen. The authors present a case in which the first brain biopsy from a 47-year-old patient with a history of heavy smoking was compatible with metastatic small cell carcinoma, and the second biopsy taken during decompression craniotomy 3 weeks later was compatible with WHO Grade IV glioblastoma. Using short tandem repeat (STR) analysis of the two specimens and nontumor-derived patient DNA, the authors found that the two specimens did not belong to the same individual. The authors conclude that allele imbalance or loss of heterozygosity detected by STR analysis is a reliable and valuable diagnostic tool for clarifying discrepancies in discordant pathology reports.

OBJECTIVE: Postoperative drawings of aneurysms serve as visual records and teaching tools for neurosurgeons and reinforce 3D vascular configurations that are specific for different cerebral aneurysms. This report brings this time-honored tradition back into focus in the digital era, and examines our experience with this technique, particularly in respect to the training of neurosurgical residents. METHODS: After craniotomy for aneurysm, a formal postoperative drawing was created and reviewed. Microsurgical issues graphically highlighted included the totality of aneurysmal dome anatomy, position of visible and hidden branch vessels, rupture points, clipping techniques, and location of adjacent cranial nerves. Drawings were cataloged and categorized according to location. RESULTS: Six hundred and nineteen drawings (ACA 221, MCA 154, ICA 214, Posterior Circulation 30) were created over a 28-year period, during a continuous series of 1,480 microsurgically treated aneurysms. Postoperative drawings in each location are presented and reviewed. Drawings demonstrated site-specific microsurgical approaches, morphologies, and points of obscuration and rupture. CONCLUSION: Creation and review of postoperative drawings are important adjuncts for the development of 3D understanding of aneurysmal anatomy. This classic art has impact in the digital age and allows patterns of morphology, projection and anatomy to be reinforced. Surgical atlases are created that function as reference and teaching tools. The creation of postoperative drawings should be a routine part of the training and methodology of vascular neurosurgeons.

BACKGROUND:EC-IC bypass for the treatment of a hypoperfused hemisphere is currently the treatment of choice for symptomatic moyamoya patients. Use of the combination of direct (STA-MCA) and indirect (an STA branch lay-on bypass and flipped dural flaps; EDAS) EC-IC bypass is advocated as the optimal treatment option as it allows immediate augmentation of flow in the postoperative period while allowing the brain to acquire additional indirect flow in the long term. METHODS:We describe the technical nuances of a combined direct and indirect bypass in a 41-year-old woman with moyamoya syndrome diagnosed with transient ischemic attacks (TIAs) and cognitive decline. CONCLUSION/CONCLUSIONS:Combined direct and indirect bypass option should become a familiar treatment modality among vascular neurosurgeons. KEY POINTS/CONCLUSIONS:(1) Pay critical attention to not injuring the Superficial Temporal Artery, Parietal branch (STApb) while turning the skin incision anteriorly. Use the operating microscope to dissect the STApb. (2) Always mark the origin of the Superficial Temporal Artery, Frontal branch (STAfb) on the skin so that its location can be anticipated during STApb dissection. (3) When no frontal branch is available or if the frontal branch is of poor quality, the STApb can be used as a direct or indirect graft. (4) A craniotomy should be done 2-3 cm posterior to the course of the STApb to allow for adequate exposure for an indirect graft. (5) Manipulation of the donor vessels should be done with extreme care as spasm of the artery or intraluminal thrombosis may occur. Low cut flow in the direct graft should be interpreted with caution as vasospasm can result in significant temporary reduction of flow. (6) Aggressive distal dissection of the direct donor is a must. The distal 1-2 cm of the vessel should be cleaned of any loose tissue and be fishmouthed prior to anastomosis. (7) A blood-free field is mandatory. Perforators on the backside of the recipient should be sacrificed and cut to avoid backbleeding into the anastomotic segment during temporary occlusion. (8) When recirculating after the anastomosis has been completed, open the temporary clips on the recipient first. Backflow into the donor segment confirms a patent anastomosis. (9) Utilization of intraoperative angiography is not necessary as long as one utilizes flow measurements and ICG angiography. (10) Take great care with the bone flap reconstruction and the skin closure as the grafts can easily be compressed or sutured. Create a generous craniectomy in the bone flap to avoid any graft compression.

OBJECT/OBJECTIVE:Intraoperative seizures during awake craniotomy may interfere with patients' ability to cooperate throughout the procedure, and it may affect their outcome. The authors have assessed the occurrence of intraoperative seizures during awake craniotomy in regard to tumor location and the isocitrate dehydrogenase 1 (IDH1) status of the tumor. METHODS:Data were collected in 137 consecutive patients who underwent awake craniotomy for removal of a brain tumor. The authors performed a retrospective analysis of the incidence of seizures based on the tumor location and its IDH1 mutation status, and then compared the groups for clinical variables and surgical outcome parameters. RESULTS:Tumor location was strongly associated with the occurrence of intraoperative seizures. Eleven patients (73%) with tumor located in the supplementary motor area (SMA) experienced intraoperative seizures, compared with 17 (13.9%) with tumors in the other three non-SMA brain regions (p < 0.0001). Interestingly, there was no significant association between history of seizures and tumor location (p = 0.44). Most of the patients (63.6%) with tumor in the SMA region harbored an IDH1 mutation compared with those who had tumors in non-SMA regions. Thirty-one of 52 patients (60%) with a preoperative history of seizures had an IDH1 mutation (p = 0.02), and 15 of 22 patients (68.2%) who experienced intraoperative seizures had an IDH1 mutation (p = 0.03). In a multivariate analysis, tumor location was found as a significant predictor of intraoperative seizures (p = 0.002), and a trend toward IDH1 mutation as such a predictor was found as well (p = 0.06). Intraoperative seizures were not associated with worse outcome. CONCLUSIONS:Patients with tumors located in the SMA are more prone to develop intraoperative seizures during awake craniotomy compared with patients who have a tumor in non-SMA frontal areas and other brain regions. The IDH1 mutation was more common in SMA region tumors compared with other brain regions, and may be an additional risk factor for the occurrence of intraoperative seizures.

Proximally located posterior communicating artery (PCoA) aneurysms, projecting postero-laterally in proximity to the tentorium, may pose a technical challenge for microsurgical clipping due to obscuration of the proximal aneurysmal neck by the anterior petroclinoid fold. We describe an efficacious technique utilizing fenestration of the anterior petroclinoid fold to facilitate visualization and clipping of PCoA aneurysms abutting this aspect of the tentorium. Of 86 cases of PCoA aneurysms treated between 2003 and 2013, the technique was used in nine (10.5 %) patients to allow for adequate clipping. A 3 mm fenestration in the anterior petroclinoid ligament is created adjacent and lateral to the anterior clinoid process. This fenestration is then widened into a small wedge corridor by bipolar coagulation. In all cases, the proximal aneurysm neck was visualized after the wedge fenestration. Additionally, an adequate corridor for placement of the proximal clip blade was uniformly established. All cases were adequately clipped, with complete occlusion of the aneurysm neck and fundus with preservation of the PCoA. There were two intraoperative ruptures not related to creation of the wedge fenestration. One patient experienced post-operative partial third nerve palsy, which resolved during follow-up. We describe a technique of fenestration of the anterior petroclinoid fold to establish a critical and safe corridor for both visualization and clipping of PCoA aneurysms.

BACKGROUND:: Internal maxillary artery (IMax) to middle cerebral artery (MCA) bypass has been recently described as an alternative to cervical EC-IC bypass. This technique utilizes a "key hole" craniectomy in the temporal fossa that requires a technically challenging end-to-side anastomosis. OBJECTIVE:: To describe a lateral subtemporal craniectomy of the middle cranial fossa floor to facilitate wide exposure of the IMax to facilitate bypass. METHODS:: Orbito-Zygomatic osteotomy is used followed by fronto-temporal craniotomy and subsequently lateral temporal fossa craniectomy, reaching its medial border at a virtual line connecting the foramen rotundum and foramen ovale. The IMax was identified by using established anatomical landmarks, neuronavigation and microdoppler. Additionally, we studied the approach in a cadaveric specimen in preparation for microsurgical bypass. RESULTS:: There were four cases in which the technique was utilized. One bypass was performed for flow augmentation in a hypo-perfused hemisphere. The other three were performed as part of treatment paradigms for giant MCA aneurysms. Vein grafts were used in all patients. The proximal anastomosis was performed in an end-to-side fashion in one patient, and end-to-end in three patients. Intraoperative graft flow measured with the Transonic flow probe ranged from 20-60 cc/min. Postoperative angiography demonstrated good filling of the graft with robust distal flow in all cases. All patients tolerated the procedure well. CONCLUSION:: IMax to MCA subcranial to intracranial (SC-IC) bypass is safe and efficacious. The lateral temporal fossa craniectomy technique resulted in reiable identification and wide exposure of the IMax, facilitating the proximal anastomosis.

BACKGROUND: Aneurysms located at the proximal posterior inferior cerebellar artery (PICA) may need to be addressed by trapping and concomitant bypass. An anastomosis of the Occipital Artery (OA) to PICA is one bypass option in these cases. This bypass is highly challenging and its technical description is seldom cited in the literature. METHODS: We describe the technical nuances of an OA-PICA end-to-side bypass in a 63-year-old man with a dissecting ruptured aneurysm of the third segment (tonsilomedullary) of the PICA. CONCLUSION: OA-PICA bypass option should remain as a treatment modality in the armamentarium of neurovascular surgeons.