Abstracts

Rationale: Current conventional medical therapies for West syndrome (WS) that include adrenocorticotropic hormone (ACTH) often fail to control spasms, particularly in cases with structural etiologies. Surgical resection has recently been applied for such refractory spasms, achieving relatively good seizure outcomes if the responsible epileptogenic focus can be identified. Another problem in WS is the encephalopathic influence on developmental outcomes. Early response to ACTH treatment is associated with favorable cognitive outcomes in cases of unknown etiology. On the other hand, a structural etiology and asymmetrical features of seizures and EEG, which may facilitate surgical treatment, are associated with a higher risk of developmental decline. The posterior cortex, including the parietal, occipital and temporal lobes, is most often targeted for surgical treatment in WS, but postoperative cognitive outcomes have yet to be fully investigated.  Methods: This study retrospectively reviewed our results for resective or disconnective surgery (RDS) of the posterior cortex in 12 patients with WS. Five patients who had initially responded to ACTH treatment were defined as ACTH responders (ACTH-Rs), with recurrence of spasms prevented for 4-44 months. The remaining seven patients did not experience remission of spasms and were defined as ACTH non-responders (ACTH-NRs). MRI demonstrated cortical malformation in 6 patients, focal vascular insult in 1 and no focal lesion in 5. Among patients with MRI lesions, RDS was an initial option for 3 patients based on clear EEG focality. In the remaining 9 patients, stepwise procedures of callosotomy and RDS were applied with an interval of 4-31 months, because of less lateralized features of spasms and EEG. Age at initial surgery ranged from 8 to 83 months old and follow-up ranged from 6 to 71 months. Results: Six patients remained seizure-free as of final follow-up. Developmental outcomes were assessed using developmental quotient (DQ), including motor, language and social subscales. Postoperative overall DQ and scores for each subscale were significantly higher among ACTH-Rs than among ACTH-NRs. Postoperative DQ gains in receptive language, expressive language and social relationship with adults were significantly greater among ACTH-Rs than among ACTH-NRs. In contrast, no significant difference in postoperative DQ gains for physical motor and manipulation were evident between groups. Other factors including age, MRI and seizure outcome were not associated with developmental outcomes. Conclusions: Epilepsy surgery of the posterior cortex had a greater impact on language and social development among ACTH-R patients with recurrent spasms. This suggests that: 1) even transient remission of spasms with appropriate ACTH treatment may minimize encephalopathic influences on cognitive functions; 2) ACTH may be effective when the epileptogenic lesion is more localized, preserving the recovery potential of cognitive functions; and 3) surgical treatment may also be beneficial from a developmental perspective in patients with recurrent spasms after ACTH treatment.   Funding: N/A