Reading Tea Leaves: The Predictive Value of Individual CSF Parameters or Post-operative Hydrocephalus Following Hemispherectomy for Pediatric Drug-resistant Epilepsy

Introduction: Hydrocephalus is a debilitating complication following hemispherectomy. We study the utility of using individual cerebrospinal fluid (CSF) parameters (red blood cells (RBC), protein, white blood cells (WBC), glucose) in predicting post-operative hydrocephalus following hemispherectomy for drug-resistant epilepsy.

Methods: We retrospectively reviewed all institutional pediatric hemispherectomies from 2002-2016. Univariable and multivariable analysis were performed. Subgroup analysis was done on patients with CSF diversion.

Results: Two hundred and fifty patients (53.6% Male) were identified. Median age was 6.2 (2.9-12.0) years at surgery. Techniques varied: 105 (42%) patients underwent functional hemispherectomy, 78 (31.2%) anatomic, 59 (23.6%) a modified anatomic, and 8 (3.2%) had peri-insular resection. 200 (80%) patients had post-operative CSF drainage via ventriculostomy with a mean of 1.5+/-1.3 days of total drainage. Hydrocephalus occurred in 9.6% of patients. Overall age, gender, technique, pathology, surgical history, and post-operative CSF drainage showed no significant association with the development of hydrocephalus. Subgroup analysis of the 200 patients who were drained post-operatively was performed. Gender, age, technique, pathology, length of drainage, individual CSF parameters on the first day of drainage, the last day of drainage, and the relative change between those values, were considered using stepwise regression. Gender, age, surgical technique, protein value on the last day, and the relative change in RBC were included in the final model. Anatomic hemispherectomy when compared to functional or modified increased the likelihood of hydrocephalus (OR 1.74 95%CI 1.03-2.95, p=0.04). Higher relative reduction in RBC decreased the likelihood of hydrocephalus (OR 0.99 95%CI 0.99-0.99, p=0.02). No further significant associations were found.

Conclusion : This is the first study to consider the utility of individual CSF parameters for prediction of hydrocephalus following hemispherectomy surgery. Relative reduction of RBC in the CSF imparts a very small decrease in the likelihood of developing hydrocephalus, but is much less significant than the effect seen by surgical technique.