Structural changes in the gray matter of the contralateral hemisphere and prognosis of motor function in children with pharmacoresistant epilepsy before and after hemispherotomy.

OBJECTIVE

Hemispherotomy (HS) is an effective treatment option to control seizures for children with pharmacoresistant epilepsy. We aimed to explore the alteration of the gray matter structure before and after surgery and identify the specific brain regions associated with preoperative neuropsychological development and postoperative motor development.

METHODS

We conducted a retrospective study of magnetic resonance imaging (MRI) results, clinical parameters and follow-up data in 46 children who underwent hemispherotomy (HS) at our hospital between 2018 and 2022, and 32 controls were included. Voxel-based morphometry (VBM) and surface-based morphometry (SBM) techniques were employed to quantify the alteration of the gray matter structure. We used Spearman rank correlation and logistic regression models to analyze the influence of different factors on neuropsychological development and motor outcome.

RESULTS

46 children with pharmacoresistant epilepsy undergoing hemispherotomy and 32 control subjects were recruited for this study. The patients were divided into two groups according to their surgical side: 29 patients with the left hemispherotomy (13 females, 17 months [IQR, 26 months]) and 17 patients with the right hemispherotomy (11 females, 19 months [IQR, 27.5 months]). Finally, 36 patients completed 13.80±1.54 months (LHS)/ 11.53±1.73 months (RHS) of follow-up, and 89.0 % remained completely seizure-free (outcome scale class IA). The prefrontal cortex showed a positive correlation with neuropsychological development before surgery. Cortical thickness (CT) of the anterior cingulate gyrus was an independent protective factor [OR=18.19, 95 % CI (1.56-212.43), P = 0.021] for motor function prognosis after surgery, while gray matter volume (GMV) of the temporal pole of the middle temporal gyrus was an independent risk factor [OR=0.07, 95 % CI (0.01-0.85), P = 0.037] after surgery.

SIGNIFICANCE

Preoperative remodeling of prefrontal cortical gray matter structures in the contralateral hemisphere was performed for functional compensation. After surgery, the prefrontal and cingulate cortices resumed the normal developmental trajectories, with the cingulate cortex determining postoperative motor outcome. However, there is irreversible gray matter damage to the temporal lobe, leading to corresponding functional developmental deficits.