Topographical analysis of neurological outcome following motor and sensory area resection

Abstract

Introduction The resection of the motor and somatosensory area (MSA) has been challenging due to the postoperative neurological deficits. The author hypothesized that the additional resection of the adjacent area of the motor and MSA could increase the postoperative neurological risk. This study was designed to evaluate the neurological deterioration that follows the MSA resections and to assess the topographical risk factors associated with these morbidities.

Materials and Methods The author reviewed 109 consecutive patients who suffered from medically intractable epilepsy and underwent the resection of the MSA and / or adjacent area under awake anesthesia. The cohort included the 33 patients with primary motor cortex (PMC) resection, 43 patients with supplementary motor area (SMA) resection, and 24 patients with primary sensory cortex (PSC) resection. The etiological diagnoses were brain neoplasm in 54 patients (49.5%), cortical lesion in 25 (22.9%), and no lesion in 30 (27.5%). All topographical analyses of the resected area were performed based upon pre- and post-operative magnetic resonance images.

Results After the PMC resection, 67% of the patients experienced neurological worsening including 15% of the permanent deficits. The postoperative neurological worsening was not significantly associated with the additional adjacent area resection, but with the specific location (e.g., posterior upper quadrant) of the resected area of the PMC. The SMA syndrome occurred in the 47% of the patients who underwent SMA resection, and this was significantly associated with the additional resection of the cingulate gyrus. The neurological risk of the PSC resection was 40%. The additional resection of the posterior parietal cortex (PPC) was the significant risk factor for the development of postoperative neurological impairments.

Conclusion After the resection of the MSA and its adjacent area, 48% of the patients experienced neurological impairments including 9% of the permanent deficits. The additional resection of the cingulate gyrus and the PPC increased significantly the postoperative neurological risk after the SMA and PSC resection, respectively. The results imply that the neurological outcome after the resection of the MSA may be influenced by the disruption of the network between the eloquent and its adjacent area rather than the damage of the only eloquent area.