Impairment of motor function after frontal lobe resection with preservation of the primary motor cortex

Abstract

Clinical course and characteristics of the motor deficits were investigated in patients who underwent surgical resection of the frontal lobe for tumorous lesions. The extent of resection was classified into four groups. In Group A, resection was limited within the area above the superior frontal sulcus and posterior to a line vertical to the AC-PC line at the AC (VCA line). Resection was extended anterior to the VCA line in Group B or below the superior frontal sulcus in Group C. In Group D, resection was extended to both of these two boundaries. In results, permanent and severe motor deficit is rarely induced when resection of the frontal lobe is limited to only the SMA proper (corresponding roughly to Group A), the SMA proper and pre-SMA (corresponding roughly to Group B), or the SMA proper and premotor cortex (corresponding roughly to Group C), insofar as the primary motor cortex is preserved. Disturbance in fine movements of the upper extremity is frequently induced for the long term when wide areas of the SMA proper, pre-SMA as well as premotor cortex are resected all together (corresponding roughly to Group D).