gms | German Medical Science

Objective: Postsurgical seizure in patients with chronic subdural hematoma (cSDH) is a well known but poorly investigated phenomenon. Apart from pre-existing epilepsy, alcohol withdrawal and electrolyte imbalances, surgical factors might be significant determinators.

Method: Clinical, radiological and surgical variables in patients with cSDH were retrospectively analyzed and correlated to the incidence of postsurgical seizures.

Results: 131 consecutive patients have been included. Mean age was 74,4 years, 66% were male. Presurgical epilepsy was evident in 6,9% patients, 2,3% were alcohol addicts. cSDH was bihemispheric in 19,8%, unilateral in 80,2%. Most cSDH were frontoparietal or frontotemporal (80,2%). 80% showed septations or cortical capsules, 29,9% were subacute with fresh clots of hematoma. Mean thickness of cSDH was 20,4 ± 6,2 mm in axial planes. Midline shift averaged 6,3 ± 4,6 mm. 127 patients were operated using a burr-hole or mini-craniotomy, 25 patients had bilateral approaches. Pre- to postoperative cSDH reduction was significant (mean of difference -9,7 mm, p<0,0001). The JPD-to-brain angles were 43,3 ± 25,8° in axial and 51,4 ± 30,4° in coronal planes. In 19,8%, JPD showed cortical contact with eloquent regions (15 precentral gyrus, 11 Sylvian fissure), in 56%, the JPD somehow crossed the precentral region. In 7,6% patients, trapping of space-occupying subdural air was seen.

Surgical complications consisted of cortical bleeding in 3%, some fresh subdural hematoma surrounding the JPD in 29,8% and wound infections in 5,3% patients. 13 patients (9,9%) required multiple operations per side for efficient cSDH reduction. 14 (10,7%) patients suffered from postsurgical seizures (focal in 13 and general in 1 patient). Seizures resolved spontaneously in 1 case, 11 required antiepileptic drugs or early removal of the JPD. Postsurgical seizures were independent of presurgical epilepsy, alcohol abuse, localization and thickness of hematoma, kind of surgery, JPD localization and angle, subdural air entrapment or electrolyte levels. Instead, the risk of seizure was significantly correlated to the presence of hyperintense clots in the presurgical CT scan (p=0,0492) and to the number of operations per side (>1) (p=0,0053).

Conclusions: Postsurgical seizures in cSDH can be anticipated in patients with subacute rather than chronic SDH and in those in need for a surgical revision. In these, prophylactic use of antiepileptic medication might be useful.