Efficacy of lamina terminalis fenestration in reducing shunt-dependent hydrocephalus following aneurysmal subarachnoid hemorrhage: a systematic review

Abstract

Chronic hydrocephalus requiring shunt placement is a common complication following aneurysmal subarachnoid hemorrhage (SAH). Controversy exists over whether microsurgical fenestration of the lamina terminalis during aneurysm surgery affords a reduction in the development of shunt-dependent hydrocephalus. To resolve this debate, the authors performed a systematic review and quantitative analysis of the literature to determine the efficacy of lamina terminalis fenestration in reducing aneurysmal SAH-associated shunt-dependent hydrocephalus. A MEDLINE (1950-2007) database search was performed using the following keywords, singly and in combination: "ventriculoperitoneal shunt," "hydrocephalus," "subarachnoid hemorrhage," "aneurysm," "fenestration," and "lamina terminalis." Additional studies were manually singled out by scrutinizing references from identified manuscripts, major neurosurgical journals and texts, and personal files. A recent study from the authors' institution was also incorporated into the review. Data from included studies were analyzed using the chi-square analysis and Student t-test. The Cochran-Mantel-Haenszel test was used to compare overall incidence of shunt-dependent hydrocephalus. The literature search revealed 19 studies, but only 11 were included in this review, involving 1973 patients. The fenestrated and nonfenestrated cohorts (combined from the various studies) differed significantly with regard to patient sex, age, and clinical grade as well as aneurysm location (p=0.0065, 0.0028, 0.0003, and 0.017, respectively). The overall incidence of shunt-dependent hydrocephalus in the fenestrated cohort was 10%, as compared with 14% in the nonfenestrated cohort (p=0.089). The relative risk of shunt-dependent hydrocephalus in the fenestrated cohort was 0.88 (95% CI 0.62-1.24). This systematic review revealed no significant association between lamina terminalis fenestration and a reduced incidence of shunt-dependent hydrocephalus. The interpretation of these results, however, is restricted by unmatched cohort differences as well as other inherent study limitations. Although the overall literature supports lamina terminalis fenestration, a number of authors have questioned the technique's benefits, thus rendering its efficacy in reducing shunt-dependent hydrocephalus unclear. A well-designed, multicenter, randomized controlled trial is needed to definitively address the efficacy of this microsurgical technique.