Ventriculoperitoneal shunting after aneurysmal subarachnoid hemorrhage: analysis of the indications, complications, and outcome with a focus on patients with borderline ventriculomegaly.

Objective: The goals of this study were to investigate the risk factors, indications, complications, and outcome for patients with ventriculoperitoneal shunts (VPSs) after subarachnoid hemorrhage and to define a subgroup eligible for future prospective studies designed to clarify indications for placement of a VPS.
Methods: Clinical characteristics of 236 prospectively evaluated patients with subarachnoid hemorrhage and 6 months of follow-up were analyzed. Hydrocephalus was estimated by the relative bicaudate index (RBCI) measured on computed tomographic scans at the time of shunting. Patients were divided into three groups by ventricle size: Group 1 included 121 patients with small ventricles (RBCI <1.0), Group 2 included 88 patients with borderline ventricle size (RBCI 1.0-1.4), and Group 3 included 27 patients with markedly enlarged ventricles (RBCI >1.4).
Results: Initially, 86 patients (36%) underwent ventriculoperitoneal shunting: 19 in Group 1 (16%), 43 in Group 2 (49%), and 24 in Group 3 (90%). Indications for placement of a VPS, risk factors, and outcome differed markedly by group. Four patients (3% of those not initially shunted) developed delayed hydrocephalus requiring a VPS, including one in Group 2 (2%). The 6-month shunt complication rate was 13%. Evaluation of patients in Group 2 indicated that functional status was an important factor in selecting candidates for shunting, and that patients receiving shunts and shunt-free patients demonstrated improvement in functional status during follow-up.
Conclusion: Although we currently use a proactive shunting paradigm for posthemorrhagic hydrocephalus, this report demonstrates that a conservative approach to patients with borderline ventricle size (i.e., RBCI of 1.0-1.4) and normal intracranial pressure should be evaluated in a prospective randomized trial.