Analysis of Hemispherotomy and Posterior Quadrant Disconnection Surgery for Medically Intractable Epilepsy in Very Young Patients

Introduction: Hemispherotomy and posterior quadrant disconnection (PQD) are standard surgical treatments for medically intractable epilepsy in pediatric patients. However, current academic literature is limited on their efficacy and safety in very young patients. This study evaluates outcomes of patients 12 months old and younger who underwent hemispherotomy or PQD.

Methods: We retrospectively reviewed patients 12 months old and younger who underwent epilepsy surgery at Washington University and St Louis Children’s Hospital from 2003 to 2023. Data on diagnosis, age at surgery, operative details, length of hospital stay, and complications were reported. The Engel classification and Gross Motor Function Classification System (GMFCS) were used to assess seizure and motor outcomes, respectively.

Results: A total of n=14 patients who underwent either hemispherotomy (n=12) or PQD (n=2) were included. 57% had a diagnosis of hemimegaloencephaly, 29% had middle cerebral artery infarcts, and 14% had cortical development malformation. Average age at surgery was 6 months with the youngest child being 2 months old. Average estimated blood loss was 58% of total blood volume. Average duration of follow-up was 4.8 years. At one year post-op, seizure freedom was 83%. At last follow-up, 54% of patients were free of disabling seizures (Engel I) with 57% of this subgroup being completely seizure free (Engel IA). 23% of patients experienced rare disabling seizures (Engel II) and 23% experienced worthwhile improvement (Engel III). At last follow-up, 66% of patients were GMFCS level I or II (walking with no or some limitations) and 34% were GMFCS level IV (assisted self-mobility). There were no deaths or long-term postoperative complications.

Conclusion : This cohort’s outcomes are comparable to reported averages of seizure freedom and GMFCS levels I or II in older children, being 74% and 68%, respectively. Hemispherotomy and PQD are safe and effective surgical procedures for treating medically intractable epilepsy in very young patients.