Clipping of UIA and postoperative cognition

MCA aneurysm

J Neurosurg 120:937–944, 2014

The mechanisms underlying neurocognitive changes after surgical clipping of unruptured intracranial aneurysms (UIAs) are poorly understood. The aim of this study was to investigate factors that determine postoperative cognitive decline after UIA surgery.

Methods. Data from 109 patients who underwent surgical clipping of a UIA were retrospectively evaluated. These patients underwent neuropsychological examinations (NPEs), including assessment by the Wechsler Adult Intelligence Scale- Third Edition and the Wechsler Memory Scale-Revised before and 6 months after surgical clipping of the UIA. Results of NPEs were converted into z scores, from which pre- and postoperative cognitive composite scores (CSpre and CSpost) were obtained. The association between the change in CS between pre- and postoperative NPEs (that is, CSpost – CSpre [CSpost – pre]) and various variables was assessed. These latter variables included surgical approach (anterior interhemispheric approach or other approach), structural change evidenced on T2-weighted imaging at 6 months, somatosensory evoked potential amplitude decrease greater than 50% during aneurysm manipulation, preexisting multiple ischemic lesions in the lacunar region detected on preoperative T2-weighted imaging, and total microsurgical time. Paired t-tests of the NPE scores were performed to determine the net effect of these factors on neurocognitive function at 6 months.

Results. A significant CSpost – pre decrease was observed in patients with a structural change on postoperative T2-weighted imaging when compared with those without such a change on postoperative T2-weighted imaging (-0.181 vs 0.043, p = 0.012). Multiple regression analysis demonstrated that postoperative T2-weighted imaging change independently and negatively correlated with CSpost – pre (p = 0.0005). In group-rate analysis, postoperative NPE scores were significantly improved relative to preoperative scores.

Conclusions. Minimal structural damage visualized on T2-weighted images at 6 months as a result of factors such as pial/microvascular injury and excessive retraction during surgical manipulation could cause subtle but significant negative effects on postoperative neurocognitive function after surgical clipping of a UIA. However, this detrimental effect was small, and based on the group-rate analysis, the authors conclude that successful and meticulous surgical clipping of a UIA does not adversely affect postoperative cognitive function.

Fenestration of the lamina terminalis during aneurysm surgery

Lamina terminalis fenestration

J Neurosurg 119:629–633, 2013

Fenestration of the lamina terminalis (FLT) during aneurysm surgery for subarachnoid hemorrhage can, in theory, improve CSF circulation from the lateral and third ventricles to the cortical subarachnoid space, which may, in turn, decrease the incidence of hydrocephalus and vasospasm. However, the actual effects of FLT on CSF circulation have been difficult to determine, due to confounding factors. In addition, it is unclear whether the lamina terminalis remains functionally patent when the brain resumes its normal position. The goal of this study was to assess the functional patency of the fenestrated lamina terminalis in patients who underwent surgery for ruptured aneurysms.

Methods. This prospective study included 15 patients who underwent surgical clipping of ruptured anterior circulation aneurysms, with FLT performed during surgery. On postoperative Day 1, the external ventricular drain of each patient was closed, and 1 ml of Omnipaque 300, an iodine-based contrast agent, was injected intraventricularly, accompanied by cranial maneuvering designed to position the contrast agent adjacent to the lamina terminalis. Three to 5 minutes after cranial maneuvering, the flow of contrast agent into the basal cisterns was assessed with CT imaging. Flow was verified by an increase in Hounsfield units in a prespecified “region of interest” within the basal cisterns on the CT scan. This procedure was performed using a standardized protocol designed in consultation with the Department of Radiology and approved by the institutional review board. One patient who underwent endoscopic third ventriculostomy was recruited as a positive control to validate the technique, and 1 patient who underwent aneurysm clipping but not FLT was recruited as a negative control.

Results. Seventeen patients consented to study participation. In the 15 patients who underwent aneurysm clipping and FLT, and the negative control patient who underwent aneurysm clipping but not FLT, the contrast agent followed the normal ventricular pathway from the lateral ventricles into the fourth ventricle, and did not appear in the basal cisterns. In the positive control patient, the contrast agent robustly and immediately filled the basal cisterns.

Conclusions. Fenestration of the lamina terminalis did not result in functional patency of the lamina terminalis when performed as part of surgical clipping for ruptured aneurysms.

Complex middle cerebral artery aneurysms. A new classification

Complex MCAA-a new classification

Acta Neurochir (2013) 155:1481–1491

Because of the diversity of aneurysm morphology, complicated arterial anatomy and hemodynamic characteristics, tailored surgical treatments are required for cases of individual complex middle cerebral artery (MCA) aneurysms.

Methods During an 8-year period, 59 complex MCA aneurysms in 58 patients were treated microsurgically in our department. Complex aneurysms were defined as having large (10–24 mm in diameter) or giant (diameter≥25 mm) size or non-saccular morphology (fusiform, dissecting or serpentine).

Results Direct clipping of the aneurysmal necks was achieved in eight patients, while reconstructive clipping was performed in 25 patients. Indirect aneurysm occlusion was performed in 25 cases, including trapping or resecting the aneurysm in four cases, trapping or resecting the aneurysm with extraintracranial (EC) or intra-intracranial (IC) bypass in 21 cases and internal carotid artery (ICA) sacrifice with EC-IC bypass in one case. Forty-eight aneurysms (81.4 %) were completely obliterated. Graft patency was confirmed in 20 of 21 cases (95.2 %) with bypass. A recurrent aneurysm was detected in one case and a re-operation was performed. Two patients with Hunt-Hess grade IV aneurysms died during the perioperative period. Overall, 52 cases (88.1 %) had good outcomes (Glasgow Outcome Scale≥4) during the late follow-up period.

Conclusion The surgical modality and strategy for treating complex MCA aneurysm are decided according to the morphology of the aneurysm, vascular anatomy and the hemodynamic characteristics of each case. Thus, we developed a new classification based on the angioarchitecture. Favorable outcomes can be achieved by treating complex MCA aneurysms with appropriate surgical modalities, strategies and techniques.

Intra-arterial Injection Fluorescein Videoangiography in Aneurysm Surgery

Intra_arterial_Injection_Fluorescein

Neurosurgery 72[ONS Suppl 2]:ons141–ons150, 2013

To visualize blood flow in the arteries and aneurysm during surgery, intravenous fluorescence videoangiography has been used. However, the image contrast with this procedure is diminished by repeated study because the dye remains for about 10 minutes after injection.

OBJECTIVE: To determine the optimal dye concentration and to clarify the usefulness of fluorescein videoangiography by intra-arterial dye injection.

METHODS: In the pilot study, fluorescein sodium dissolved at various concentrations was illuminated with excitation light, and fluorescence was detected by cameras. The fluorescence of 0.001% fluorescein sodium solution mixed with plasma at various concentrations was then examined. In 13 aneurysm patients, dye solution was administered through the catheter for intraoperative digital subtraction angiography. The intravenous injection method was also performed, and the findings were compared.

RESULTS: Dye was clinically used at a concentration of 0.005% to 0.1% on the basis of the results of the pilot study. Fluorescence emission from the vessels and aneurysms was clearly observed by both methods; however, arterial injection provided brighter emission, resulting in clearer demonstration of the bloodstream than venous injection. Dye clearance was also quicker, which allowed repeat injections without delay. Dye filling in the aneurysm indicating incomplete occlusion was detected in 2 cases, and occlusion of the perforating artery was observed in 2 cases.

CONCLUSION: Intra-arterial fluorescein videoangiography provides brighter and clearer imaging of blood flow with a smaller dose of dye than intravenous videoangiography. It can be repeated within a short time and is useful for detecting incomplete clipping or unexpected obstruction of arteries.

Patterns of Aneurysm Recurrence After Microsurgical Clip Obliteration

Patterns of Aneurysm Recurrence After Microsurgical Clip Obliteration

Neurosurgery 72:65–69, 2013

Microsurgical clip obliteration remains a time-honored and viable option for the treatment of select aneurysms with very low rates of recurrence.

OBJECTIVE: We studied previously clipped aneurysms that were found to have recurrences to better understand the patterns and configurations of these rare entities.

METHODS: A retrospective review was performed of 2 prospectively maintained databases of aneurysm treatments from 2 institutions spanning 14 years to identify patients with recurrence of previously clipped intracranial aneurysms.

RESULTS: Twenty-six aneurysm recurrences were identified. Three types of recurrence were identified: type I, proximal to the clip tines; type II, distal; and type III, lateral. The most common type of recurrence was that arising distal to the clip tines (46.1%), and the least frequently encountered recurrence was that arising proximal to the tines (19.2%). Laterally located recurrences were found in 34.6% of cases.

CONCLUSION: We describe 3 different patterns of aneurysm recurrence with respect to clip application: those occurring proximal, distal, or lateral to the clip tines.

Clinical presentation and treatment of distal anterior inferior cerebellar artery aneurysms

Neurosurg Rev (2012) 35:497–504

Aneurysms located at the distal portion of the anterior inferior cerebellar artery (AICA) are rare, and their clinical features are not fully understood. We report the clinical features and management of nine distal AICA aneurysms in nine patients treated during the past decade at Kagoshima University Hospital and affiliated hospitals.

Our series includes seven women and two men. Of their nine aneurysms, eight were ruptured and one was unruptured; six were saccular and three were dissecting aneurysms. The most prevalent location was the meatal loop (n=5) followed by the postmeatal (n=3) and premeatal segment (n=1) of the AICA, suggesting hemodynamic stress as an etiology of these distal AICA aneurysms. Of the nine patients, five presented with angiographic features suggestive of increased hemodynamic stress to the AICA and the common trunk of the posterior inferior cerebellar artery, with vertebral artery stenosis, marked laterality, and a primitive hypoglossal artery.

We addressed eight aneurysms (eight patients) surgically; one aneurysm in one patient disappeared in the course of 3 months without surgical treatment. Of the eight surgically treated aneurysms, seven were ruptured and one was unruptured, five were clipped via lateral suboccipital craniotomy, two were trapped via lateral suboccipital craniotomy, and one was embolized. Good outcomes were obtained in six of the eight patients who underwent operation (75 %).

We consider increased hemodynamic stress attributable to anatomic variations in the AICA and related posterior circulation to be the predominant contributor to the development of distal AICA aneurysms. Direct clipping and trapping yielded favorable outcomes in our series.

Surgical Management of Giant Posterior Communicating Artery Aneurysms

Neurosurgery 71[ONS Suppl 1]:ons43–ons51, 2012

Giant posterior communicating artery (PCoA) aneurysms (> 25 mm) are rare lesions associated with a poor prognosis and high rates of morbidity and mortality.

OBJECTIVE: To review the clinical results of giant PCoA aneurysms surgically treated at our institution, focusing on operative nuances.

METHODS: All cases of giant PCoA aneurysms treated surgically at our institution were identified from a prospectively maintained patient database. Patient demographic factors, medical comorbidities, rupture status, neurological presentation, clinical outcomes, and surgical records were critically reviewed.

RESULTS: From 1989 to 2010, 11 patients (10 women) underwent surgical clipping of giant PCoA aneurysms. Presenting signs and symptoms included cranial nerve palsies, diminished mental status, headache, visual changes, and seizures. Five aneurysms were ruptured on admission. All aneurysms were clipped primarily except 1, which was treated by parent artery sacrifice and extracranial-to-intracranial bypass after intraoperative aneurysm rupture. Perioperative morbidity and mortality rates were 36% (4 of 11) and 18.3% (2 of 11), respectively. Excellent or good clinical outcomes, defined as modified Rankin Scale scores ≤ 2, were achieved in 86% (5 of 6) of patients available for long-term clinical follow-up (mean, 12.5 ± 13.6 months).

CONCLUSION: Giant PCoA aneurysms are rare vascular lesions that may present with a variety of neurological signs and symptoms. These lesions can be successfully managed surgically with satisfactory morbidity and mortality rates. To the best of our knowledge, this is the largest surgical series of giant PCoA aneurysms published to date.

Exclusively intradural exposure and clip reconstruction in complex paraclinoid aneurysms

Acta Neurochir (2011) 153:2103–2109. DOI 10.1007/s00701-011-1171-6

The management of complex paraclinoid aneurysms is still challenging. In this article we describe our approach to paraclinoid aneurysms, which has evolved over several years, using an exclusively intradural approach.

Method All procedures are done under continuous electrophysiological monitoring. A standard pterional approach is used to access the paraclinoid region exclusively intraduraly. After optic nerve unroofing and tailored clinoidectomy, the aneurysm neck is visualized and clipped using the tandem clipping technique and suction decompression if necessary. Aneurysm occlusion is verified using intraoperative ICG angiography and postoperative 3D DSA.

Conclusion The exclusively intradural approach to complex paraclinoid aneurysms with tailored clinoidectomy offers an excellent surgical corridor for the treatment of these challenging lesions

Preoperative Evaluation of Unruptured Cerebral Aneurysms by Fast Imaging Employing Steady- State Acquisition Image

Neurosurgery 69:412–420, 2011 DOI: 10.1227/NEU.0b013e318213431e

In aneurysm surgery, understanding the microanatomy around the aneurysm such as perforating arteries and cranial nerves is mandatory.

OBJECTIVE: To assess the usefulness in determining the microanatomy around the cerebral aneurysms by the use of fast imaging employing steady-state acquisition (FIESTA) images of magnetic resonance imaging preoperatively, in addition to computed tomography and digital subtraction angiography.

METHODS: Between October 2006 and June 2009, 123 patients with 140 unruptured cerebral aneurysms were treated in our institution. Eighty-two patients were assessed with FIESTA by the operators on the workstation of the magnetic resonance image before surgical clipping of the aneurysms. The small vessels and cranial nerves were confirmed intraoperatively before or after obliteration of the aneurysms.

RESULTS: Sensitivities and specificities of FIESTA imaging were 100% in detecting hypothalamic artery around anterior communicating artery aneurysms, oculomotor nerve attachment to the posterior communicating artery aneurysm domes, and anterior choroidal artery adhesion to the posterior communicating artery aneurysms. This technique was also useful for predicting adhesion between the aneurysm and adjacent main trunks or perforators. Although the specificity was 100%, sensitivity was 56% in detecting vessel adhesion around the middle cerebral aneurysms. This technique can provide limited information in large aneurysms or aneurysms located in minimal cerebrospinal fluid space. The overall outcomes of the patients included 120 excellent recoveries, 1 moderate deficit, 1 severe deficit, and 1 persistent vegetative state according to the Glasgow Outcome Scale.

CONCLUSION: By giving information on the minute anatomical structure around the aneurysm, FIESTA can contribute to thorough preoperative evaluations of cerebral aneurysms.

Clipping of MCA aneurysms: how I do it

Acta Neurochir (2011) 153:1361–1366. DOI 10.1007/s00701-011-1063-9

Aneurysms located at the middle cerebral artery bifurcation remain a clear neurosurgical indication. We detail here the steps necessary to enable safe surgery for Sylvian fissure aneurysms.

Methods: An angiogram with 3D reconstruction is obtained and reviewed intraoperatively, just prior to the skin incision. During the exposure, the cistern is kept open by small cottonoids, thereby avoiding brain retraction. Continuous monitoring of MEPs along with ICG microscopic angiofluorescence allows for detection of vascular compromise. Intraoperative angiography with 3D reconstruction allows for immediate correction of less than satisfactory surgical outcome.

Conclusions Careful planning of surgical strategy followed by a minimally invasive technique (with continuous neuro-monitoring) ensures safe surgery. The availability of intra-operative radiological guidance allows for optimal management.

Clinical presentation and treatment of distal posterior inferior cerebellar artery aneurysms

Neurosurg Rev. DOI 10.1007/s10143-010-0296-z

Aneurysms located at the distal portion of the posterior inferior cerebellar artery (PICA) are rare, and their clinical features are not fully understood. We report the clinical features and management of 30 distal PICA aneurysms in 28 patients treated during the past decade at Kagoshima University Hospital and affiliated hospitals.

Our series includes 20 women and eight men. Of their 30 aneurysms, 24 were ruptured, and six were unruptured; there were 27 saccular and two fusiform aneurysms; one was dissecting. Their location was at the anterior-medullary (n=4), lateral-medullary (n=9), tonsillomedullary (n=7), telovelotonsillar (n=6), and cortical (n =4) segment of the PICA. In 18 patients, angiographic features suggested hemodynamic stress including an absent contralateral PICA or ipsilateral anterior inferior cerebellar artery, termination of the vertebral artery (VA) at the PICA, and hyperplasia or occlusion of the contralateral VA.

As three patients died before surgery, 27 aneurysms in 25 patients were surgically treated. Of these, 6 were unruptured aneurysms; 20 were clipped via midline or lateral suboccipital craniotomy, and 5 were embolized with Guglielmi coils; in one, the PICA flow was reconstructed by OA-PICA anastomosis, and in the other one, the PICA was resected.

Of the 25 surgically treated patients, 22 (88%) had good outcomes. The predominant contributor to the development of distal PICA aneurysms is thought to be increased hemodynamic stress attributable to anomalies in the PICA and related posterior circulation. Both direct clipping and coil embolization yielded favorable outcomes in our series. However, considering the difficulties that may be encountered at direct clipping in the acute stage and the availability of advanced techniques and instrumentation, aneurysmal coiling is now the first option to address these aneurysms.

Postoperative Assessment of Clipped Aneurysms With 64-Slice Computerized Tomography Angiography

Neurosurgery 67:844-854, 2010 DOI: 10.1227/01.NEU.0000374684.10920.A2

Multidetector computerized tomography angiography (MDCTA) is now a widely accepted technique for the management of intracranial aneurysms.

OBJECTIVE: To evaluate its accuracy for the postoperative assessment of clipped intracranial aneurysms.

METHODS:We analyzed a consecutive series of 31 patients that underwent direct surgical clipping procedures of 38 aneurysms. A 64 slice MDCT scanner (Aquilion 64, Toshiba) was used and results were compared with digital subtraction angiographies (DSA). Two independent neuroradiologists analyzed the following data: examination quality, artifacts, aneurysm remnant, and patency of collateral branches. Interobserver agreement, sensitivity, and specificity were calculated.

RESULTS: Seventy-nine percent of the aneurysms were located in the anterior circulation. Significant artifacts were found with multiple and cobalt-alloy clips. According to DSA, remnants >2 mm were found in 21% of the cases, and 2 patients had one collateral branch occluded. Sensitivity and specificity of 64-MDCTA for the detection of aneurysm remnants were 50% and 100%, respectively. Sensitivity and specificity of 64-MDCTA for the detection of a significant remnant (>2 mm) and the detection of the occlusion of a collateral branch were, respectively, 67% and 100% and 50% and 100%. No relationship was found with the location, type, shape, size, or number of clips, but missed remnants tended to be larger with cobalt-alloy clips.

CONCLUSIONS: 64-MDCTA is a valuable technique to assess the presence of a significant postoperative remnant in single titanium clip application cases and might be useful for longterm follow-up. DSA remains the most accurate postoperative radiological examination.

Postoperative Assessment of Clipped Aneurysms With 64-Slice Computerized Tomography Angiography

Neurosurgery 00:000-000, 2010 DOI: 10.1227/01.NEU.0000374684.10920.A2

Multidetector computerized tomography angiography (MDCTA) is now a widely accepted technique for the management of intracranial aneurysms.

OBJECTIVE: To evaluate its accuracy for the postoperative assessment of clipped intracranial aneurysms.

METHODS:We analyzed a consecutive series of 31 patients that underwent direct surgical clipping procedures of 38 aneurysms. A 64 slice MDCT scanner (Aquilion 64, Toshiba) was used and results were compared with digital subtraction angiographies (DSA). Two independent neuroradiologists analyzed the following data: examination quality, artifacts, aneurysm remnant, and patency of collateral branches. Interobserver agreement, sensitivity, and specificity were calculated.

RESULTS: Seventy-nine percent of the aneurysms were located in the anterior circulation. Significant artifacts were found with multiple and cobalt-alloy clips. According to DSA, remnants >2 mm were found in 21% of the cases, and 2 patients had one collateral branch occluded. Sensitivity and specificity of 64-MDCTA for the detection of aneurysm remnants were 50% and 100%, respectively. Sensitivity and specificity of 64-MDCTA for the detection of a significant remnant (>2 mm) and the detection of the occlusion of a collateral branch were, respectively, 67% and 100% and 50% and 100%. No relationship was found with the location, type, shape, size, or number of clips, but missed remnants tended to be larger with cobalt-alloy clips.

CONCLUSIONS: 64-MDCTA is a valuable technique to assess the presence of a significant postoperative remnant in single titanium clip application cases and might be useful for longterm follow-up. DSA remains the most accurate postoperative radiological examination.

Coil Embolization of Remnant or Recurred Intracranial Aneurysm After Clipping

Neurosurgery 66:1128-1133, 2010 DOI: 10.1227/01.NEU.0000367998.33743.D6

To evaluate clinical presentation, safety, techniques, clinical and angiographic outcomes, and prognostic factors of coiling for remnant/recurred aneurysm after clipping.

METHODS:Twenty-four consecutive patients (11 men and 13 women; mean age, 52 years) with 24 recurred/remnant aneurysms after clipping underwent coil embolization between September 2000 and December 2008. Clinical presentations of remnant/recurred aneurysms, safety, techniques, clinical and angiographic outcomes, and prognostic factors of coil embolization were retrospectively evaluated.

RESULTS: Twenty-two aneurysms initially presented with subarachnoid hemorrhage and the other two, with mass effect. Eight aneurysms presented with rebleeding and 16 aneurysms were found on follow-up CT angiogram (n = 12) or catheter angiogram (n = 4). The interval between clipping and coiling ranged from 8 days to 114 months (mean, 31 months). Twelve were treated by using single-catheter, 6 by stent-assisted, 4 by multicatheter, 1 by both balloon- and catheter-assisted, and 1 by balloon-in-stent technique. Immediate postembolization angiogram revealed complete obliteration (n = 19) or residual neck (n = 5). Procedure-related permanent morbidity and mortality rates were 4.2% (1 of 24) and 0%, respectively. There was no rebleeding during clinical follow-up for 3 to 82 months (mean, 24 months). Presentation with rupture after clipping was the only significant predictor of poor outcome (P < .05).

CONCLUSION: Coiling seems to be a safe and effective retreatment option for remnant/ recurred aneurysm after clipping. Presentation with rupture after clipping is the only predictor of poor outcome. For routine/regular follow-up after clipping, CT angiography may be the imaging modality advisable for detection of remnant/recurred aneurysm.


Three-dimensional simulation for aneurysm surgery

Neurosurgery 65:719–726, 2009 DOI: 10.1227/01.NEU.0000354350.88899.07

OBJECTIVE: With improvements in endovascular techniques, fewer aneurysms are treated by surgical clipping, and those aneurysms targeted for open surgery are often complex and difficult to treat. We devised a hollow, 3-dimensional (3D) model of individual cerebral aneurysms for preoperative simulation and surgical training. The methods and initial experience with this model system are presented.

METHODS:The 3D hollow aneurysm models of 3 retrospective and 8 prospective cases were made with a prototyping technique according to data from 3D computed tomographic angiograms of each patient. Commercially available titanium clips used in our routine surgery were applied, and the internal lumen was observed with an endoscope to confirm the patency of parent vessels. The actual surgery was performed later.

RESULTS: In the 8 prospective cases, the clips were applied during surgery in the same direction and configuration as in the preoperative simulation. Fine adjustments were necessary in each case, and 2 patients needed additional clips to occlude the atherosclerotic aneurysmal wall. With these 3D models, it was easy for neurosurgical trainees to grasp the vascular configuration and the concept of neck occlusion. Practicing surgery with these models also improved their handling of the instruments used during

aneurysm surgery, such as clips and appliers.

CONCLUSION: Using the hollow 3D models to simulate clipping preoperatively, we could treat the aneurysms confidently during live surgery. These models allow easy and concrete recognition of the 3D configuration of aneurysms and parent vessels.

Intracranial-intracranial arterial by-pass for complex aneurysms

Neurosurgery 65:670–683, 2009 DOI: 10.1227/01.NEU.0000348557.11968.F1

OBJECTIVE: Bypass surgery for brain aneurysms is evolving from extracranial-intracranial
(EC-IC) to intracranial-intracranial (IC-IC) bypasses that reanastomose parent arteries,
revascularize efferent branches with in situ donor arteries or reimplantation, and reconstruct bifurcated anatomy with grafts that are entirely intracranial. We compared results with these newer IC-IC bypasses to conventional EC-IC bypasses.
METHODS: During a 10-year period, 82 patients underwent bypass surgery as part of their aneurysm management. A quarter of the patients presented with ruptured aneurysms and two-thirds presented with compressive symptoms from unruptured aneurysms. Most aneurysms (82%) had non-saccular morphology and 56% were giant sized. Common locations included the cavernous internal carotid artery (23%), middle cerebral artery (20%), and posteroinferior cerebellar artery (12%).
RESULTS: Forty-seven patients (57%) received EC-IC bypasses and 35 patients (43%)received IC-IC bypasses, including 9 in situ bypasses, 6 reimplantations, 11 reanastomoses, and 9 intracranial grafts. Aneurysm obliteration rates were comparable in ECIC and IC-IC bypass groups (97.9% and 97.1%, respectively), as were bypass patency rates (94% and 89%, respectively). Three patients died (surgical mortality, 3.7%), and 4 patients were permanently worse as a result of bypass occlusions (neurological morbidity,4.9%). At late follow-up (mean duration, 41 months), good outcomes (Glasgow Outcome Scale score 5 or 4) were measured in 68 patients (90%) overall, and were similar in EC-IC and IC-IC bypass groups (91% and 89%, respectively). Changes in Glasgow Outcome Scale score were slightly more favorable with IC-IC bypass (6% worse or dead after IC-IC bypass versus 14% with EC-IC bypass).
CONCLUSION: IC-IC bypasses compare favorably to EC-IC bypasses in terms of aneurysm obliteration rates, bypass patency rates, and neurological outcomes. IC-IC bypasses can be more technically challenging to perform, but they do not require harvest of extracranial donor arteries, spare patients a neck incision, shorten interposition grafts, are protected inside the cranium, use caliber-matched donor and recipient arteries, and are not associated with ischemic complications during temporary arterial occlusions. IC-IC bypass can replace conventional EC-IC bypass with more anatomic reconstructions for selected aneurysms involving the middle cerebral artery, posteroinferior cerebellar artery, anterior cerebral artery, and basilar apex.