Perianeurysmal edema in giant intracranial aneurysms in relation to aneurysm location, size, and partial thrombosis.

OBJECT: The underlying mechanisms causing intracranial perianeurysmal edema (PAE) are still poorly understood. Since PAE is most frequently observed in giant intracranial aneurysms (GIAs), the authors designed a study to examine the occurrence of PAE in relation to the location, size, and partial thrombosis (PT) of GIAs along with the clinical impact of PAE. METHODS: Magnetic resonance imaging data for patients with a diagnosis of unruptured GIA from the international multicenter Giant Intracranial Aneurysm Registry were retrospectively analyzed with regard to location and size of the GIA, PAE volume, and the presence of PT. The occurrence of PAE was correlated to clinical findings. RESULTS: Imaging data for 69 GIAs were eligible for inclusion in this study. Perianeurysmal edema was observed in 33.3% of all cases, with the highest frequency in GIAs of the middle cerebral artery (MCA; 68.8%) and the lowest frequency in GIAs of the cavernous internal carotid artery (ICA; 0.0%). Independent predictors of PAE formation were GIA volume (OR 1.13, p = 0.02) and the occurrence of PT (OR 9.84, p = 0.04). Giant intracranial aneurysm location did not predict PAE occurrence. Giant aneurysms with PAE were larger than GIAs without PAE (p < 0.01), and GIA volume correlated with PAE volume (rs = 0.51, p = 0.01). Perianeurysmal edema had no influence on the modified Rankin Scale score (p = 0.30 or the occurrence of aphasia (p = 0.61) or hemiparesis (p = 0.82). CONCLUSIONS: Perianeurysmal edema was associated with GIA size and the presence of PT. As no PAE was observed in cavernous ICA aneurysms, even though they exerted mass effect on the brain and also displayed PT, the dura mater may serve as a barrier protecting the brain from PAE formation.

Quantifying unruptured giant intracranial aneurysms by measuring diameter and volume--a comparative analysis of 69 cases.

BACKGROUND: Intracranial aneurysms (IA) are usually quantified according to their largest diameter. However, volumetry has recently been increasingly conducted as well, especially in giant intracranial aneurysms (GIAs). Since so far the true value of GIA volumetry is unknown, we designed a trial to examine correlations between GIA diameter and volume with special focus on clinical implications. METHODS: Magnetic resonance imaging of 69 unruptured GIAs in 66 patients was retrospectively evaluated. The largest diameter and volume were measured. Also, potential associations to the patients' clinical conditions were examined. RESULTS: Comparing GIA sizes of our patient cohort produced different results depending on whether GIA diameter or volume was measured. Measuring the diameter identified posterior circulation GIAs as the largest ones (39.2 mm, IQR 37.3-48.3), while measuring the volume found GIAs of the MCA to be the largest ones (12.3 cm(3), IQR 7.2-27.8). A correlation of GIA diameter and volume was only found in anterior circulation GIAs, which were predominantly saccular in shape, but not in those of the posterior circulation, of which most were fusiform. Neither GIA diameter nor GIA volume but only GIA location was associated with neurological deficits. CONCLUSION: Diameter and volume measurements are not interchangeable modes of GIA quantification. Our data suggest that the idea of distinguishing different sizes of GIA may be clinically less relevant than examining their location, shape or mass effect.

Collagen matrix in decompressive hemicraniectomy.

OBJECTIVE: Decompressive hemicraniectomy is an accepted treatment for otherwise untreatable intracranial hypertension. The aim of this prospective randomized study is to evaluate the benefit of application of collagen matrix as an onlay graft to reduce operating time during hemicraniectomy and to facilitate dural dissection during second-stage cranioplasty. METHODS: Thirty-four consecutive patients were randomized to receive collagen matrix during hemicraniectomy or to undergo the conventional procedure. Specific time points were recorded during hemicraniectomy and cranioplasty. Intra- and postoperative complications, time course of Glasgow Coma Scale, Barthel's, and Early Rehabilitation Indices were monitored. The surgeon had to rate the convenience of the procedure if collagen matrix was used. Cost implications are discussed. RESULTS: The use of collagen matrix during hemicraniectomy resulted in a reduction of combined operating time for hemicraniectomy and cranioplasty by an average of 19.7%. The rate of cerebrospinal fluid effusion during cranioplasty was 13% when collagen was used and 58% in the control group. None of the patients who received collagen developed cerebrospinal fluid effusion persisting longer than 1 week, compared with 33% of patients in the control group. A total of 85% of the surgeons rated the use of collagen matrix as being easier than usual; the rest did not see a difference. CONCLUSION: The use of collagen matrix to cover the dural defect during hemicraniectomy reduces operating time in hemicraniectomy and cranioplasty. The complication rate (cerebrospinal fluid effusion), total treatment time, and time on intensive care unit can be reduced, giving a potential for cost reduction. There was no difference in the rehabilitative outcome.