Motor cortex stimulation for chronic neuropathic pain: a preliminary study of 10 cases

Abstract

There is growing evidence to support the use of motor cortex stimulation (MCS) in the management of patients with chronic neuropathic pain. A prospective audit of ten patients using a modified staged technique for motor cortex implantation provides further evidence for the analgesic effectiveness of this technique. Ten patients suffering from phantom limb pain (n=3), post stroke pain (n=5), post traumatic neuralgia secondary to gunshot injury to the brain stem (n=1) and brachyalgia secondary to neuro-fibromatosis (n=150% pain relief) and long-term benefit in 4/5 of patients who initially responded to intermittent cortical stimulation (longest follow up 31 months after implantation). Of those patients who benefited two had post stroke pain, two phantom limb pain and one post-traumatic neuralgia. We conclude that motor cortex stimulation is an effective analgesic intervention in some patients with chronic neuropathic pain, but it is difficult if not impossible to predict those patients who may respond to treatment prior to implantation. Randomised controlled trials are now urgently needed to test the effectiveness of motor cortex stimulation under double-blind conditions.

Recording of Corticospinal Evoked Potential for Optimum Placement of Motor Cortex Stimulation Electrodes in the Treatment of Post-stroke Pain -Two Case Reports-

“…[2][3][4]7,8,[11][12][13]16,17,22) In the large series, the long-term success rate for pain alleviation was about 50%. The pain control provided by motor cortex depends on stimulation of neuronal circuits mediated by corticospinal tract neurons originating from the motor cortex.…”

A Tool for Topographic Analysis of Electrode Contacts in Human Cortical Stimulation

“…Electric chronic stimulation of motor cortex (ECSM) through epidural electrodes has been reported to control chronic pain [4,18]. However the mechanism of action of ECSM is still hypothetical because of our poor knowledge of both biophysical and pathophysiologic mechanisms.…”

Epidural motor cortex stimulation with functional imaging guidance

“…Since their initial reports, other groups have reported procedure-related success in treating deafferentation pain syndromes of varying causes, with success rates ranging from 50 to 80% for both central and trigeminal neuropathic pain. 1,6,8 This procedure, in which minimal rates of morbidity have been demonstrated, is gaining increasing acceptance.Precise intraoperative placement of the stimulating electrode over the motor cortex region corresponding to the painful body part is essential to successful outcome. Although most groups have reported intraoperative electrophysiological confirmation of motor cortex by using SSEP and/or EMG monitoring, initial localization techniques vary.…”

“…Since their initial reports, other groups have reported procedure-related success in treating deafferentation pain syndromes of varying causes, with success rates ranging from 50 to 80% for both central and trigeminal neuropathic pain. 1,6,8 This procedure, in which minimal rates of morbidity have been demonstrated, is gaining increasing acceptance.…”

“…The use of surface anatomical landmarks, scalp SSEPs, and computerized tomography and MR imaging-guided systems have all been reported. 1,3,7,8,13 Functional imaging information, such as that obtained using MEG, fMR imaging, and optical imaging, is now routinely integrated into many neurosurgical procedures, including tumor/arteriovenous malformation resection and epilepsy surgery. Sole reliance on anatomical criteria for determination of eloquent cortex has been shown to have limitations, and the integration of such functional imaging data is a useful adjunct in preoperative planning and risk assessment as well as for intraoperative guidance.…”