Abstracts

Rationale: Infants with refractory West syndrome are at high risk for developing severe mental retardation. Pinard et al. (1993, 1999) reported the effect of corpus callosotomy (CC) for epilepsy after West syndrome. However, further study has not been reported. In this study, we analyzed surgical outcome, change of psychomotor developments and prognostic factors of CC in patients with West syndrome. Methods: CC was performed in 35 patients with West syndrome under 5 years old. Age at the seizure onset ranged from 0 to 1.8 years (mean 0.3). Normal developments were observed in 11 patients before the onset of epilepsy. All patients had video-EEG monitoring, neuropsychological examination, MRI and inter-ictal ECD SPECT. Patients with resectable lesion on MRI were excluded. Age at the surgery ranged from 0.4 to 4.6 years. Anterior CC was performed in 2 patients and total CC in 33 patients with a mean follow-up period of 3 years. For a psychological test, Kinder Infant Developmental Scale (KIDS) was used at each follow-up point. For assessment of post-operative change of developments, developmental velocity (DV) was used, which was calculated from the difference of developmental age (DA) before the surgery and at the each follow-up point, divided by the number of follow-up months. Surgical outcome was categorized as free (F, seizure free), excellent (E, greater than 80% reduction in seizure frequency), good (G, greater than 50% reduction in seizure frequency) and poor (P, no significant change). Results: During preoperative EEG-video monitoring, 21 patients showed single type of seizure and 14 had multiple types of seizure. Tonic spasm was recorded in all patients except for 3, whose seizure was tonic seizure. Preoperative developmental quotient (DQ) and DA is mean 20.6 and 5 months, respectively. MRI showed diffuse brain atrophy in 28 patients. Surgical outcome was F in 9 (26%), E in 7 (20%), G in 10 (28%) and P in 9 patients (26%). 74% of patients showed significant improvements after the surgery. Pre-operative prognostic factors were analyzed between F+E group and G+P group with multivariate analysis. Late onset of seizure (p<0.05), higher preoperative DQ (p<0.05) and normal developments before the onset of epilepsy (p<0.001) are significant predictive factors for seizure control. In F + E group, DV was greater than in G + P group at the each follow-up point. Furthermore, in F + E group, patients with preoperative DQ greater than 20 showed significantly higher DV than those with lower DQ at the final follow-up point. Conclusions: CC was an effective and important therapeutic option in patients with intractable West syndrome. Best results were obtained in patients who had late onset of epilepsy, higher in DQ and normal development before the onset of epilepsy. For postoperative improvements of psychomotor function, an early surgery is recommended before severe psychomotor delay develops.