gms | German Medical Science

Objective: Rupture of cerebral aneurysms is believed to occur due to structural changes or incomplete development of vessel walls. Intimal loss, a poorly developed lamina elastica interna, and a fibrotic or necrotic tunica media are commonly observed. The aim of this retrospective study was to examine these alterations in ruptured (ra) versus unruptured aneurysms (unra) and to analyze their correlation with clinical course.

Methods: Among patients operated from 2000 to 2005 because of cerebral aneurysm in our neurosurgical department, the surgeon decided to take specimens for histological examination from the clipped aneurysm dome in 103 cases (ra: n=89, unra: n=14, ♀=64%, ♂=36%) dependent on situs and aneurysm configuration. Specimens were fixed in formalin, embedded in paraffin and stained by hematoxylin & eosin and van Gieson's. The following histopathologic features were scored: infiltration of vessel –walls by leukocytes, presence of muscle cells of tunica media, fibrotic tissue, necrotic areas and periadventitial vessels. Patient’s charts were used to extract clinical information.

Results: Histological specimens of unra and ra differed with respect to presence of fibrosis (93% vs. 61%, p<0.05), muscle cells (86% vs. 39%, p=0.001), necrotic areas (0% vs. 49%, p=0.001), periadventitial vessels (7% vs. 28%, p=0.094) and infiltration by leukocytes (0% vs. 70%, p<0.001). Leukocytic infiltration in the ra group was associated with occurrence of vasospasms (flow velocity >120 cm/sec, p=0.014) and length of hospitalization (p=0.005).

Conclusions: Our results show differences in histopathologic appearance of ruptured versus un-ruptured cerebral aneurysms. Furthermore, leukocytic infiltrates may serve as indicators for a worse postoperative clinical course of the patient.