[Motor cortex stimulation for post-stroke pain using neuronavigation and evoked potentials: report of 3 cases]

Although motor cortex stimulation (MCS) has been accepted as an effective therapeutic option for central pain, the efficacy of MCS widely varies among previous reports. In this report, we describe our recent trial for successful MCS in 3 patients with central pain due to cerebral stroke. Medical treatments were transiently effective, but gradually became ineffective in all of the cases. During surgery, the appropriate cortical target was determined by using neuronavigation, somatosensory evoked potential (SEP), and motor evoked potential (MEP). A flat, four-plate electrode was positioned on the dura mater parallel to the motor cortex. After surgery, pain almost resolved in 2 of 3 patients and markedly improved in another. The pain relief depended on their motor function. These findings strongly suggest that both patient selection and intraoperative monitoring for targeting the motor cortex are quite important for successful MCS, although further studies were essential.