Faculty Bibliography

BACKGROUND:An extended retrosigmoid approach can offer sufficient space for clip reconstruction of some high-riding posterior inferior cerebellar artery (PICA) aneurysms. OBJECTIVE:To quantitatively investigate the glossopharyngo-cochlear triangle (GCT) and anatomic structures within it. METHODS:Extended retrosigmoid craniotomies were performed on 10 sides of cadaveric heads, and the GCT was identified in each specimen. The length of the base and the area of the GCT were measured. The depth of the vertebrobasilar system and the abducens nerve to the GCT were measured. The proximal and distal exposable and controllable points on the vertebrobasilar system were identified. Two imaging-based patient selection algorithms are provided using the lengths from those points to the vertebral artery dural entry point and the superoinferior distances from those points to the inferior edge of the foramen magnum. Other factors related to accessibility via the GCT were investigated. RESULTS:The mean (standard deviation [SD]) area of the GCT was 45.7 (12.55) mm2. The mean (SD) depth of the abducens nerve was 14.3 (1.42) mm. The mean (SD) superoinferior distances from the foramen magnum to those points were 23.1 (7.39), 24.7 (8.25), 30.0 (9.56), and 32.6 (7.79) mm, respectively. The lower segment of the vertebrobasilar system was more superficial in the setting of a high-lying vertebrobasilar junction (VBJ) than a low-lying VBJ. CONCLUSION:We describe the GCT in an extended retrosigmoid approach for high-riding PICA aneurysms and evaluate the spatial relationship of the neurovascular structures within it. Two potential algorithms are offered for preoperative patient selection.

Intellectual disability (ID) is a genetic and clinically heterogeneous common disease and underlying molecular pathogenesis can frequently not be identified by whole-exome/genome testing. Here, we report four siblings born to a consanguineous union who presented with intellectual disability and discuss the METAP1 pathway as a novel etiology of ID. Genomic analyses demonstrated that patients harbor a novel homozygous nonsense mutation in the gene METAP1. METAP1 codes for methionine aminopeptidase 1 (MetAP1) which oversees the co-translational excision of the first methionine remnants in eukaryotes. The loss-of-function mutations to this gene may result in a defect in the translation of many essential proteins within a cell. Improper neuronal function resulting from this loss of essential proteins could lead to neurologic impairment and ID.

OBJECTIVE:The SAFIRE grading scale is a novel, computable scale that predicts the outcome of aneurysmal subarachnoid hemorrhage (aSAH) patients in acute follow-up. However, this scale also may have prognostic significance in long-term follow-up and help guide further management. METHODS:The records of all patients enrolled in the Barrow Ruptured Aneurysm Trial (BRAT) were retrospectively reviewed, and the patients were assigned SAFIRE grades. Outcomes at 1 year and 6 years post-aSAH were analyzed for each SAFIRE grade level, with a poor outcome defined as a modified Rankin Scale score > 2. Univariate analysis was performed for patients with a high SAFIRE grade (IV or V) for odds of poor outcome at the 1- and 6-year follow-ups. RESULTS:A total of 405 patients with confirmed aSAH enrolled in the BRAT were analyzed; 357 patients had 1-year follow-up, and 333 patients had 6-year follow-up data available. Generally, as the SAFIRE grade increased, so did the proportion of patients with poor outcomes. At the 1-year follow-up, 18% (17/93) of grade I patients, 22% (20/92) of grade II patients, 32% (26/80) of grade III patients, 43% (38/88) of grade IV patients, and 75% (3/4) of grade V patients were found to have poor outcomes. At the 6-year follow-up, 29% (23/79) of grade I patients, 24% (21/89) of grade II patients, 38% (29/77) of grade III patients, 60% (50/84) of grade IV patients, and 100% (4/4) of grade V patients were found to have poor outcomes. Univariate analysis showed that a SAFIRE grade of IV or V was associated with a significantly increased risk of a poor outcome at both the 1-year (OR 2.5, 95% CI 1.5-4.2; p < 0.001) and 6-year (OR 3.7, 95% CI 2.2-6.2; p < 0.001) follow-ups. CONCLUSIONS:High SAFIRE grades are associated with an increased risk of a poor recovery at late follow-up.

BACKGROUND:Treatment of small ruptured aneurysms (SRAs) remains controversial, with literature reporting difficulty with endovascular versus microsurgical approaches. This paper analyzes outcomes after endovascular coiling and microsurgical clipping among patients with SRAs prospectively enrolled in the Barrow Ruptured Aneurysm Trial (BRAT). METHOD:All BRAT patients were included in this study. Patient demographics, aneurysm size, aneurysm characteristics, procedure-related complications, and outcomes at discharge and at 1-year and 6-year follow-up were evaluated. A modified Rankin scale (mRS) score > 2 was considered a poor outcome. RESULTS:Of 73 patients with SRAs, 40 were initially randomly assigned to endovascular coiling and 33 to microsurgical clipping. The rate of treatment crossover was significantly different between coiling and clipping; 25 patients who were assigned to coiling crossed over to clipping, and no clipping patients crossed over to coiling (P < 0.001). Among SRA patients, 15 underwent coiling and 58 underwent clipping; groups did not differ significantly in demographic characteristics or aneurysm type (P ≥ 0.11). Mean aneurysm diameter was significantly greater in the endovascular group (3.0 ± 0.3 vs 2.6 ± 0.6; P = 0.02). The incidence of procedure-related complications was similar for endovascular and microsurgical treatments (odds ratio [95% confidence interval], 1.0 [0.1-10.0], P = 0.98). Both groups had comparable overall outcome (mRS score > 2) at discharge and 1-year and 6-year follow-up (P = 0.48 and 0.73, respectively). CONCLUSIONS:Most SRA patients in the BRAT underwent surgical clipping, with a high rate of crossover from endovascular approaches. Endovascular treatment was equivalent to surgical clipping with regard to procedure-related complications and neurologic outcomes.

OBJECTIVE:Takotsubo cardiomyopathy (TC) in patients with aneurysmal subarachnoid hemorrhage (aSAH) is associated with high morbidity and mortality. Previous studies have shown that female patients presenting with a poor clinical grade are at the greatest risk for developing TC. Intra-aortic balloon pumps (IABPs) are known to support cardiac function in severe cases of TC, and they may aid in the treatment of vasospasm in these patients. In this study, the authors investigated risk factors for developing TC in the setting of aSAH and outcomes among patients requiring IABPs. METHODS:The authors retrospectively reviewed the records of 1096 patients who had presented to their institution with aSAH. Four hundred five of these patients were originally enrolled in the Barrow Ruptured Aneurysm Trial, and an additional 691 patients from a subsequent prospectively maintained aSAH database were analyzed. Medical records were reviewed for the presence of TC according to the modified Mayo Clinic criteria. Outcomes were determined at the last follow-up, with a poor outcome defined as a modified Rankin Scale (mRS) score > 2. RESULTS:TC was identified in 26 patients with aSAH. Stepwise multivariate logistic regression analysis identified female sex (OR 8.2, p = 0.005), Hunt and Hess grade > III (OR 7.6, p < 0.001), aneurysm size > 7 mm (OR 3, p = 0.011), and clinical vasospasm (OR 2.9, p = 0.037) as risk factors for developing TC in the setting of aSAH. TC patients, even with IABP placement, had higher rates of poor outcomes (77% vs 47% with an mRS score > 2, p = 0.004) and mortality at the last follow-up (27% vs 11%, p = 0.018) than the non-TC patients. However, aggressive intra-arterial endovascular treatment for vasospasm was associated with good outcomes in the TC patients versus nonaggressive treatment (100% with mRS ≤ 2 at last follow-up vs 53% with mRS > 2, p = 0.040). CONCLUSIONS:TC after aSAH tends to occur in female patients with large aneurysms, poor clinical grades, and clinical vasospasm. These patients have significantly higher rates of poor neurological outcomes, even with the placement of an IABP. However, aggressive intra-arterial endovascular therapy in select patients with vasospasm may improve outcome.

In situ bypasses to the anterior inferior cerebellar artery (AICA) are unusual because, with only one artery in the cerebellopontine angle (CPA), no natural intracranial donors parallel its course. In rare cases, the posterior inferior cerebellar artery (PICA) may have the tortuosity or redundancy to be mobilized to the AICA to serve as a donor. This video demonstrates this p3 PICA-to-a3 AICA in situ side-to-side bypass. A 75-yr-old woman presented with ataxia and hemiparesis from a large thrombotic right AICA aneurysm compressing the brainstem. Strategy consisted of bypass, trapping, and brainstem decompression. Written informed consent for surgery was obtained from the patient. A hockey-stick incision was made to harvest the occipital artery as a backup donor, but its diminutive caliber precluded its use. The bypass was performed through an extended retrosigmoid craniotomy. The aneurysm was trapped completely and thrombectomized to relieve the pontine mass effect. Indocyanine green videoangiography confirmed patency of the bypass, retrograde filling of the AICA to supply pontine perforators, and no residual aneurysmal filling. This unusual in situ bypass is possible when redundancy of the AICA and PICA allow their approximation in the CPA. The anastomosis is performed lateral to the lower cranial nerves in a relatively open and superficial plane. The extended retrosigmoid approach provides adequate exposure for both the bypass and aneurysm trapping. In situ AICA-PICA bypass enables anterograde and retrograde AICA revascularization with side-to-side anastomosis. The occipital artery-to-AICA bypass and the V3 vertebral artery-to-AICA interpositional bypass are alternatives when intracranial anatomy is unfavorable for this in situ bypass.1-6 Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

BACKGROUND:Aneurysms of the anterior inferior cerebellar artery (AICA) are rare. Primary clip reconstruction of these lesions is a challenge because of the limited surgical exposure and frequent nonsaccular aneurysm morphology. Endovascular treatment options exist, but outcomes are equivalent to those for open surgery. Historically, AICA aneurysms not amenable to clipping or primary coiling have been treated with parent vessel sacrifice. OBJECTIVE:To determine whether an AICA revascularization strategy would afford for the safe treatment of AICA aneurysms and other posterior circulation pathologies without compromising perfusion of the AICA territories. METHODS:We describe a series of AICA bypasses to treat 4 AICA aneurysms and 3 vertebral artery/AICA occlusions. RESULTS:We used 7 types of bypasses to revascularize the AICA territory. Bypass types included extracranial-to-intracranial (EC-IC) bypass without an interpositional graft, EC-IC with an interpositional graft, in situ bypass, reanastomosis, reimplantation, intracranial-to-intracranial bypass with interpositional graft, and combination bypasses. In particular, we performed the following 7 bypasses: OA-a3 AICA, OA-RAG-a3 AICA, p3 PICA-a3 AICA, a2 AICA reanastomosis, V4 VA-a3 AICA, V3 VA-SVG-a3 AICA, and a combined OA-a3 AICA bypass and p3 PICA reanastomosis. AICA revascularization allows for the safe treatment of AICA aneurysms and other posterior circulation pathologies without compromising perfusion of the AICA territories. CONCLUSION:All 7 AICA bypasses are feasible for application to AICA aneurysms and ischemic disease. Our experience with the 7-bypass framework demonstrates the utility of the framework as a decision-making tool and the breadth of bypass innovation possible in this anatomically challenging region.

The anterior and posterior communicating arteries are natural connections between arteries that enable different adjacent circulations to redistribute blood flow instantly in response to changing supply and demand. An analogous communication does not exist in the middle cerebral circulation. A middle communicating artery (MCoA) can be created microsurgically between separate middle cerebral artery (MCA) trunks, enabling flow to redistribute in response to changing supply and demand. The MCoA would draw blood flow from an adjacent circulation such as the external carotid circulation. The MCoA requires the application of fourth-generation techniques to reconstruct bi- and trifurcations after occluding complex MCA trunk aneurysms. In this report, the authors describe two recent cases of complex MCA bi- and trifurcation aneurysms in which the occluded efferent trunks were revascularized by creating an MCoA. The first MCoA was created with a "double-barrel" superficial temporal artery-M2 segment bypass and end-to-end reimplantation of the middle and inferior MCA trunks. The second MCoA was created with an external carotid artery-radial artery graft-M2 segment interpositional bypass and end-to-side reimplantation of the inferior trunk onto the superior trunk. Both aneurysms were occluded, and both patients experienced good outcomes. This report introduces the concept of the MCoA and demonstrates two variations. Angioarchitectural and technical elements include the donation of flow from an adjacent circulation, a communicating bypass, the application of fourth-generation bypass techniques, and a minimized ischemia time. The MCoA construct is ideally suited for rebuilding bi- and trifurcated anatomy after trapping or distally occluding complex MCA aneurysms.

Anterior inferior cerebellar artery (AICA) aneurysms are rare lesions with a predisposition for distal location and non-saccular morphology.1,2 These aneurysms are less amenable to clipping and may instead require aneurysm trapping with bypass.3 This video reports a novel bypass for a ruptured, fusiform distal AICA aneurysm. A 51-yr-old woman with newly diagnosed acquired immunodeficiency syndrome presented to the hospital with meningitis and experienced an acute neurological decline while admitted. Neuroimaging revealed a fusiform left a2-AICA aneurysm, thought to be mycotic with diffuse subarachnoid and intraventricular hemorrhage (Hunt-Hess Grade-IV). The occipital artery was harvested as an alternative donor in the myocutaneous flap using a hockey-stick incision. An extended retrosigmoid approach exposed the infectious aneurysm. After aneurysm excision, an a2-AICA-a2-AICA end-to-end reanastomosis was performed in between and deep to the vestibulocochlear nerves superiorly and the glossopharyngeal nerve inferiorly. Indocyanine green videoangiography and postoperative angiogram confirmed bypass patency. Postoperatively, she developed epidural and subdural hematomas due to human immunodeficiency virus-associated coagulopathy and/or increased aspirin sensitivity, requiring reoperation. The patient made a complete recovery at late follow-up. AICA reanastomosis is an elegant intracranial-intracranial bypass for treating distal AICA aneurysms. To our knowledge, this is the first report of AICA reanastomosis in the proximal a2-AICA (lateral pontine) segment. This technique has been reported in the literature for distally located aneurysms (a3-AICA).4 Microanastomosis for more medial AICA aneurysms must be performed deep to the lower cranial nerves. OA to a3-AICA bypass is an alternative in cases where primary reanastomosis is not technically feasible. (Published with permission from Barrow Neurological Institute).