Etiology associated with developing posthemispherectomy hydrocephalus after resection-disconnection procedures.

OBJECT: The authors sought to determine if clinical epilepsy variables, maximum daily temperature (Tmax), and blood and CSF findings were associated with the risk of developing hydrocephalus after first-time resection-disconnection hemispherectomy.

METHODS: Patients who underwent cerebral hemispherectomy in whom a standardized perioperative protocol was used, including the use of ventriculostomies (n = 79), were classified into those who developed and those who did not develop hydrocephalus requiring CSF shunts. The authors compared these 2 groups for clinical variables, Tmax, and blood and CSF studies through postoperative Day 12.

RESULTS: In this cohort, 30% of the patients required CSF shunts, of which 8% developed late hydrocephalus up to 3 years posthemispherectomy. Multivariate analysis found that etiology was associated with developing posthemispherectomy hydrocephalus. Higher shunt rates were observed for patients with hemimegalencephaly (40%; n = 15) and a history of CNS infection (100%; n = 4) compared with cortical dysplasia (17%; n = 23) and Rasmussen encephalitis (17%; n = 12). In univariate analysis, other factors associated with developing hydrocephalus were elevated maximum daily temperatures, elevated white blood cell counts, decreased CSF protein, and increased CSF red blood cell counts.

CONCLUSIONS: The findings of the study indicate that etiology was the factor most strongly associated with developing posthemispherectomy hydrocephalus. These findings suggest that there are variable mechanisms for developing hydrocephalus after cerebral hemispherectomy depending on the procedure, and in resection-disconnection operations the mechanism may involve changes in CSF bulk flow that varies by histopathology.