Marked and rapid recovery of motor strength in premotor area compared with primary motor area in surgery for brain tumors

Abstract

Changes in motor function in response to lesions in the premotor area (PM) and the primary motor area (M1) are difficult to predict. The goal of the present study was to use awake surgery to characterize the functional property of the PM or the M1 in patients with brain tumors. Neurological change before, during and after awake surgery was compared among 8 cases of patients with brain tumors located in the PM or M1. Degree of recovery after awake surgery was better for those with brain tumors in the PM (average motor strength, 2.3) when compared with those with brain tumors in the M1 (average motor strength, 1.0). Mean duration until recovery of motor strength after awake surgery was significantly shorter for those with brain tumors in the PM (4.3 days) when compared with those with brain tumors in the M1 (7.8 days) (p < 0.05). Since the degree of removal of brain tumors was greater in those with tumors in the PM when compared with those with tumors in the M1, and because the size of brain tumors in both areas were comparable, the marked and rapid recovery of motor strength after awake surgery for those with brain tumors in PM was likely related to the specific neurological properties of PM such as the redundant network of the secondary motor area. Recovery of motor strength after awake surgery for those with brain tumors located in PM was relatively marked and rapid when compared with those with brain tumors in the M1.

Key words:

• Awake surgery
• brain tumor
• fMRI
• premotor area
• primary motor area