Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Clinical Study Stereotact Funct Neurosurg 2012;90:370–378 DOI: 10.1159/000338681 Improved Dexterity after Chronic Electrical Stimulation of the Motor Cortex for Central Pain: A Special Relevance for Thalamic Syndrome Christophe Nuti a, d François Vassal a, d Patrick Mertens d, e Jean-Jacques Lemaire f Michel Magnin d Roland Peyron b–d Departments of a Neurosurgery and b Neurology, and c Pain Center, CHU Saint-Etienne, and d INSERM, U879, UCB Lyon 1 and UJM, Saint-Etienne, e Department of Neurosurgery and Pain, Hospices Civils de Lyon, Lyon, and f Deparment of Neurosurgery, CHU Clermont-Ferrand, Clermont-Ferrand, France lief and the modification of motor status. The correlation be- tween thalamic lesions and benefits in motor performance was significant (Fisher’s exact test, two-tailed, p = 0.0017). Conclusions: Up to 26% of patients estimated that MCS im- proved their motor outcome through recovered dexterity and in cases of lateral thalamic lesions. Copyright © 2012 S. Karger AG, Basel Introduction Since the first reports by Tsubokawa et al. [1, 2] electri- cal chronic stimulation of the motor cortex (MCS) has been widely used as a surgical technique that may allevi- ate medically refractory neuropathic pain, including poststroke, posttraumatic, or trigeminal neuropathic pain [3–7]. There are substantial arguments supporting the efficacy and long-term analgesic effects of MCS in patients with desperate and medically refractory cases of neuropathic pain [8, 9], and this effect is supported by the results of a recent randomized double-blind trial [10]. As ancillary results, several groups have stressed the observation that patients with MCS may also experience Key Words Dystonia  Motor cortex  Motor function  Neurostimulation Abstract Objectives: To demonstrate that motor cortex stimulation (MCS) could improve motor function in patients with neuro- pathic pain. Methods: In this prospective clinical study of 38 patients referred for MCS as treatment for their neuropathic pain, we collected any declaration of improvement in motor performance that could be attributed to MCS. Results: Ten patients (26%) declared a benefit in their motor function. Eight presented objective evidence of recovered dexterity for rapid alternating movements. A minor proportion had improvement in dystonic posture (n = 2), but none had de- tectable increased motor strength or tonus changes. Overall, 73% of the patients with limb ataxia declared a benefit after MCS. In 6 out of 10 patients (60%), the anatomic lesion re- sponsible for pain was restricted to the lateral aspect of the thalamus. All of them had either clinical or electrophysiolog- ical evidence of lemniscal dysfunction (proprioceptive atax- ia). No correlation was found between the scores of pain re- Received: July 12, 2011 Accepted after revision: April 2, 2012 Published online: August 23, 2012 Dr. Christophe Nuti Department of Neurosurgery, CHU Saint-Etienne Avenue Albert Raimond FR–42055 Saint-Etienne Cedex 2 (France) Tel. +33 477 127 723, E-Mail christophe.nuti  @  chu-st-etienne.fr © 2012 S. Karger AG, Basel 1011–6125/12/0906–0370$38.00/0 Accessible online at: www.karger.com/sfn