Abstracts

Rationale: We recently reported on resective epilepsy surgery (RES) outcomes among elderly (= 60 years old) patients in comparison to a younger (25 – 45 years of age) cohort. While the seizure outcomes and total RES related co-morbidities were similar among the two populations, we noted that subdural hygromas after RES were present only in the elderly population. Therefore, the objective of our current study was to determine the risk of subdural hygroma formation after RES in elderly patients and analyze the associated factors. Methods: After IRB approval, we searched our prospectively maintained database to identify patients who underwent RES for drug resistant epilepsy (DRE) at the age of =60 years between 1/1/2000 and 03/31/2018.  We reviewed all post-operative CT scans of each patient to find evidence of subdural hygromas. Categorical variables were described using frequencies and percentages, while continuous variables were described using means and standard deviations (for normally-distributed data) or medians and quartiles (for non-normal distributions). Results: We identified 80 elderly patients who underwent RES during the study period. There were 46 (58%) women and the mean age at the time of RES was 64.6 (±3.6) years. Temporal lobectomy was the most common form of RES, noted in 58 (72.5%) patients followed by frontal lobectomy (12 patients; 15%), multilobar resection (6 patients; 7.5%), parietal lobe resection (3 patients; 3.8%) and 1 hemispherectomy.  A total of 5 (6.25%) patients presented post-operative hygromas after RES. All of them had undergone temporal lobe resection. The time to diagnosis of subdural hygroma ranged from 1 month to 2 years post-RES. At the time of diagnosis, 3 (60%) patients were symptomatic and each presented with headaches, aphasia and contralateral weakness and confusion, respectively. The other 2 patients had incidental subdural hygromas diagnosed on imaging. All the symptomatic patients underwent evacuation of subdural collections and subjectively improved after surgery. Only one patient presented with acute bleeding in the setting of hygroma. Subdural hygroma or associated hematoma collection raged from 1.5 to 3.5 cm. Of note, one patient presented with a larger collection (3.5 cm) which was later associated with recurrent hygroma requiring re-exploration, and eventually, subdural-peritoneal derivation, which led to improvement of symptoms. Only two patients (40%) had been on Depakote, while none of patients who developed hygromas were on antiplatelets or anticoagulation therapy. Conclusions: Postoperative hygromas might portend a risk for the development of symptomatic chronic hygromas or subdural hematomas in the elderly. The present study shows that postoperative hygroma related to RES in the elderly patients is not an uncommon post-operative finding and some of these may cause morbidity, necessitating surgical intervention. As future research, we plan to explore the relation of brain atrophy in the elderly patients to the risk of development of post-RES subdural hygromas. Funding: Cleveland Clinic Foundation internal funding