O-020 Modifying Flow in the ICA Bifurcation: Pipeline Deployment from the supraclinoid ICA Extending into the M1 Segment: Clinical and Anatomical Results

BACKGROUND: Utility of the pipeline embolization device (PED) extending to the M1 segment as well as its clinical and flow consequences at the ICA bifurcation, has not clearly described. We describe clinical and anatomical flow modifications results at the ICA bifurcation. METHODS: In this retrospective analysis of patients treated for distal supraclinoid carotid aneurysms, a single PED was deployed from the proximal M1 segment to the distal supraclinoid carotid. Flow assessment prior to the procedure, to predict the competence of the ACA/AcomA complex, was achieved by formal DSA angiography and occasional manual cross compression. In all cases a single PED was deployed over the ostium of the A1, while treating a single or multiple aneurysms. Anatomical vessels diameters and ratios between the size of the proximal segments of the A1 and M1 as well as the distal ICA were assessed. Relationships between the PED nominal diameter and the diameters of the vessels at the landing zones were obtained. All measurements were evaluated in respect to flow modifications and size regression of the A1 in the immediate postoperative images, at 3 month MRI/MRA and at 6-9 month formal DSA angiography. Immediate and mid-term clinical results were assessed. RESULTS: We treated seven patients using this technique. Median age was 62. Four patients were treated for multiple aneurysms. The following aneurysms were treated: 3 posterior communicating artery aneurysms, 3 anterior choroidal artery aneurysms, 4 ICA bifurcation aneurysms and one A1 segment aneurysm. 6/7 patients demonstrated no change of flow in ACA/AComA complex at the immediate post embolization angiography. One patient demonstrated immediate antegrade flow retardation in the ipsilateral A1 segment. Five patients underwent 3-4 month MRA follow up. All demonstrated size regression of the ipsilateral A1 segment and occlusion of the neurysms. Five patients underwent mid-term follow-up angiography (5.5-12 month). Complete reversal of flow in the ipsilateral A1, was noted in 4/5 patients (Figure 1). One patient did not demonstrate any flow modification. This patient had a dominant ipsilateral A1 segment. Interestingly, ratios of the vessels participating in this bifurcation demonstrated a unique configuration of a higher A1/M1, A1/ICA ratios and a lower M1/ICA ratio, possibly in favor of maintaining patency of the ipsilateral A1. In this specific patient, a minimal length (0.97 mm) of PED was deployed in the M1 segment. This was the most oversized PED in respect to the M1 segment. All patients were stable in the post-procedural period and with no new neurological deficits. There were no clinical nor radiographic signs of ischemia. One patient experienced asymptomatic angiographic in-stent stenosis at the M1 segment. CONCLUSIONS: We found that the deployment of PED from the distal supraclinoid carotid to the M1 segment may result in reversal of flow in the ACA/AcomA complex as well as regression of the ipsilateral A1 segment. Preoperative anatomical disposition and sizing of the PED may predict the flow modification results. This modification of flow is safe and effective, based on pre-embolization flow assessments, and may be useful in treating distal ICA aneurysm by a flow diverter. DISCLOSURES: E. Nossek: None. D. Chalif: None. S. Chakraborty: None. A. Setton: None

Internal Maxillary Artery-Middle Cerebral Artery Bypass: Infratemporal Approach for Subcranial-Intracranial (SC-IC) Bypass

BACKGROUND:Internal maxillary artery (IMax)-middle cerebral artery (MCA) bypass has been recently described as an alternative to cervical extracranial-intracranial bypass. This technique uses a keyhole 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:Orbitozygomatic osteotomy is used followed by frontotemporal craniotomy and subsequently laterotemporal fossa craniectomy, reaching its medial border at a virtual line connecting the foramen rotundum and foramen ovale. The IMax was identified by using established anatomic landmarks, neuronavigation, and micro Doppler probe (Mizuho Inc. Tokyo, Japan). Additionally, we studied the approach in a cadaveric specimen in preparation for microsurgical bypass.RESULTS:There were 4 cases in which the technique was used. One bypass was performed for flow augmentation in a hypoperfused hemisphere. The other 3 were performed as part of treatment paradigms for giant middle cerebral artery aneurysms. Vein grafts were used in all patients. The proximal anastomosis was performed in an end-to-side fashion in 1 patient and end-to-end in 3 patients. Intraoperative graft flow measured with the Transonic flow probe ranged from 20 to 60 mL/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 middle cerebral artery subcranial-intracranial bypass is safe and efficacious. The laterotemporal fossa craniectomy technique resulted in reliable identification and wide exposure of the IMax, facilitating the proximal anastomosis

The art of cerebral aneurysms-3 decades of postoperative drawings: review, classification, and efficacy for training

OBJECTIVE: To focus on postoperative drawings of aneurysms, which serve as visual records and teaching tools for neurosurgeons and reinforce three-dimensional vascular configurations that are specific for different cerebral aneurysms, and examine experience with this technique, particularly in regard to the training of neurosurgical residents. METHODS: After performing craniotomy for aneurysm treatment, formal postoperative drawings were 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: Over a 28-year period, during a continuous series of 1480 microsurgically treated aneurysms, 619 drawings (221 of anterior cerebral artery, 154 of middle cerebral artery, 214 of internal carotid artery, 30 of posterior circulation) were created. Postoperative drawings in each location were presented and reviewed. Drawings demonstrated site-specific microsurgical approaches, morphologies, and points of obscuration and rupture. CONCLUSIONS: Creation and review of postoperative drawings are important adjuncts for the development of three-dimensional 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 created from postoperative drawings function as reference and teaching tools. The creation of postoperative drawings should be a routine part of the training and methodology of vascular neurosurgeons

How I do it: occipital artery to posterior inferior cerebellar artery bypass

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. 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. OA-PICA bypass option should remain as a treatment modality in the armamentarium of neurovascular surgeons

Anterior petroclinoid fold fenestration: an adjunct to clipping of postero-laterally projecting posterior communicating aneurysms

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

Modifying flow in the ACA-ACoA complex: endovascular treatment option for wide-neck internal carotid artery bifurcation aneurysms

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 \u27side-wall\u27 aneurysm. In patients with good collateral flow through the anterior communicating complex, this treatment paradigm is safe and effective

Flow-based evaluation of cerebral revascularization using near-infrared indocyanine green videoangiography

Object. Indocyanine green (ICG) videoangiography has been established as a noninvasive technique to gauge the patency of a bypass graft; however, intraoperative graft patency may not always correlate with graft flow. Altered flow through the bypass graft may directly cause delayed graft occlusion. Here, the authors report on 3 types of flow that were observed through cerebral revascularization procedures. Methods. Between February 2009 and September 2013, 48 bypass procedures were performed. Excluded from analysis were those cases in which ICG videoangiography was not performed during surgery (whether it was not available or there was a technical issue with the microscope or the quality of ICG angiography) and/or in which angiography or CT angiography was not done within 24-72 hours after surgery. After anastomosis, bypass patency was assessed first using a noninvasive technique and then with ICG videoangiography, and flow through the graft was characterized. Patients who received a vein or radial artery graft were also evaluated with intraoperative angiography. Results. Thirty-three patients eligible for analysis were retrospectively analyzed. The patients had undergone extracranial-intracranial (EC-IC) or IC-IC bypass for ischemic stroke (13 patients), moyamoya disease (10 patients), and complex aneurysms (10 patients; 6 giant or large aneurysms, 2 carotid blister-like aneurysms, and 2 dissecting posterior inferior cerebellar artery [PICA] aneurysms). Thirty-six bypasses were performed including 26 superficial temporal artery (STA)-middle cerebral artery (MCA) bypasses (2 bilateral and 1 double-barrel), 6 EC-IC vein grafts, 1 EC-IC radial artery graft, 1 PICA-PICA bypass, 1 MCA-posterior cerebral artery bypass, and 1 occipital artery-PICA bypass. Robust anterograde flow (Type I) was noted in 31 grafts (86%). Delayed but patent graft enhancement and anterograde flow (Type II) was observed in 4 cases (11%); 1 of these cases with an EC-IC vein graft degraded gradually to very delayed flow with no continuity to the bypass site (Type III). Additionally, 1 STA-MCA bypass graft revealed no convincing flow (Type III). The 5 patients with Type II or III grafts were evaluated with a flow probe and reexploration of the bypass site, and in all cases the reason the graft became occluded was believed to be recipient-vessel competitive flow. In no case was there evidence of stenosis or a technical issue at the site of the anastomosis. Three patients with Type II and the 1 patient with Type III flow (11% of procedures) did not have a patent bypass on postoperative imaging. Conclusions. Indocyanine green videoangiography is reliable for evaluating flow through the EC-IC or IC-IC bypass. The type of flow observed through the graft has a direct relationship with postoperative imaging findings. Despite the possibility of competitive flow, Type III and some Type II flows through the graft indicate the need for graft evaluation and anastomosis exploration

Ventriculoperitoneal Shunt Infection with Mycobacterium abscessus: A Rare Cause of Ventriculitis

BACKGROUND: Mycobacterium abscessus is a rapidly growing atypical mycobacterium implicated in chronic lung disease, otitis media, surgical site infections, and disseminated cutaneous diseases. It is typically seen in patients with some degree of immunosuppression. Only 1 previous case has been reported in the setting of ventriculoperitoneal (VP) shunt infection. We report a case of M abscessus as the causative organism in a VP shunt infection in an immunocompetent adult. CASE DESCRIPTION: A 67-year-old woman required VP shunt placement after aneurysmal subarachnoid hemorrhage complicated by hydrocephalus. Her course was complicated by repeat hospitalization for 2 shunt infections, the second of which did not respond to standard antibiotic therapy. Cultures repeatedly grew M abscessus. The patient continued to decline and eventually died after transfer to the palliative care service. CONCLUSIONS: Nontuberculous mycobacteria are rare, atypical organisms in the setting of VP shunt infection. Patients with ventriculitis secondary to atypical mycobacteria may exhibit drug-resistant cerebrospinal fluid pleocytosis in the face of standard antibiotic regimens