Abstracts

Rationale: Hemispheric surgery (HS), such as hemispherotomy and hemispherectomy, is applied to patients with refractory epilepsy due to unilaterally multilobar/hemispheric pathology. Usually, existing hemiparesis caused by the damaged hemisphere is included in the criteria for this treatment to avoid postoperative neurological deterioration. However, if patients have no/minimal motor deficit, identifying whether the damaged hemisphere will lose function is difficult and we may hesitate to perform this aggressive surgery. In this study, we presented a series of patients under such situations treated with central cortex-preserving multilobar surgery (CCPMS). This surgical procedure is a type of multilobar resective/disconnective surgery that does not destroy the primary sensorimotor systems. The anterior frontal cortex and posterior cortex including the temporal, occipital and posterior parietal lobes are resected/disconnected, while preserving the central cortex including the primary sensorimotor area and its fibers. Methods: Seizure and neurological outcomes were reviewed for 6 children treated with CCPMS. Median age at preoperative evaluation was 35 months (range, 9-84 months). Patients had no/minimal motor deficit preoperatively. Magnetic resonance imaging showed atrophic lesions due to infectious insults in 4 patients, tuberous sclerosis in 1 and no focal lesion in 1. All were initially treated with callosotomy because of the generalized features of seizures and electroencephalography (EEG). After callosotomy, seizures and EEG findings became asymmetrical and the patients were considered for HS. However, CCPMS was applied to avoid aggravation of neurological status. Results: CCPMS was performed in one or two stages. Multiple subpial transections on the central cortex were also applied in three patients. In 4 patients treated with two-stage CCPMS, either frontal lobe resection/disconnection or posterior quadrantectomy was applied first depending on the extent of EEG abnormality, but both surgeries were finally required because of seizure recurrence. Video-EEG with subdural electrodes was conducted before two-stage CCPMS in 3 patients, and the frontal lobe was partially resected in two of them. Median duration of follow-up after CCPMS was 16.5 months (range, 2-96 months). Among the 5 patients followed for more than 15 months, seizure-free status was achieved in 4 (80%). The patient with tuberous sclerosis continued to experience frequent seizures. The 2 patients who underwent 1-stage CCPMS experienced transient contralateral motor weakness that fully resolved within a few weeks. All patients showed improved or maintained developmental status and activities of daily life. Conclusions: Considering the surgical indications for patients with hemispheric pathology, selection should be made with care unless obvious motor deficit is present. Multistage procedures with a combination of callosotomy and CCPMS may be an alternative option to identify remaining neuronal functions as well as epileptic foci, and to avoid postoperative neurological morbidity.