Abstracts

Rationale: Callosotomy (CC) for patients with West syndrome was reported by Pinard (1993). However, long-term outcome of seizure and psychomotor developments has not been reported. From 2001 to 2012, we performed CC on 74 patients with West syndrome. Surgical outcome and changes of psychomotor developments (PD) were retrospectively analyzed. Methods: 51 patients with follow-up periods more than 2 years were included. Patients with a resectable MRI lesion were excluded. Mean age at seizure onset was 4.6 months. ACTH treatment was used in 42. Number of anti-epileptic medication ranged from 1 to 4 (mean 2.7 drugs). Mean preoperative developmental quotient (DQ) was 15.6 and developmental age (DA) was 4.1 months. 11 patients (22%) were diagnosed as EIEE at the onset of seizure and 24 (47%) showed severe psychomotor delay before onset of seizure. During preoperative EEG monitoring, 36 patients had only tonic spasms (SP). Multiple types of seizures were observed in 15. 10 had both SP and tonic seizure (TS). MRI showed no abnormality in 8, diffuse atrophy, predominantly in the frontal lobe in 41. For the assessment of psychomotor developments, we used Kinder Infant Developmental Scale (KIDS), which was developed for Japanese children. Anterior CC was performed in 2 and total CC in49. Mean age at CC was 24.4 months. Mean follow-up period was 49 months. Results: At final follow-up point, 33% of patients were seizure free (F). 20% showed excellent (E) (greater than 80% reduction in seizure frequency, 26% was good (G)(greater than 50% reduction),and 22% was poor (P)(no significant change). Results were significantly better for SP than TS. 47% of SP spasm was F and 24% showed E after CC. As compared to SP, results for TS were significantly poor. There was no seizure free patient. To confirm effects of surgical outcome on PD, we analyzed postoperative changes of PD in F + E and G + Poor group. In F + E, postoperative decline of DQ was kept at the level of preoperative state. At 12 month after CC and final follow-up point, DQ and DA were significantly higher in F + E than in P + G. Gradual decline of PD were observed in P + G. Early onset of epilepsy, presence of severe developmental delay before onset of epilepsy, longer duration from onset to surgery and presence of TS was significantly related to poor outcome. Conclusions: CC is an effective and important therapeutic option in West syndrome. Bilateral cortical recruitment through the corpus callosum may be important for generation of SP. CC is more effective on SP than TS suggesting that different mechanisms may be present. CC prevents decline of DQ in patients with favorable surgical outcome suggesting that early surgery is recommended before severe psychomotor delay develops for postoperative improvements of the psychomotor function.