Treating persistent pain with neuromodulatory techniques may be as old as human history. In the 1950s and 1960s, mainly destructive procedures of nerves, ganglia, spinal cord, or subcortical brain areas were performed for the treatment of pain and other diseases. This has changed over the last 25 years, and neurodestructive procedures were replaced by neurostimulation.1-9 Invasive neurostimulation is performed at various sites of the peripheral and central nervous system. Invasive stimulation of the precentral gyrus and motor cortex areas for central pain syndromes was first published in 1991 by Tsubokawa’s group.10 According to the relevant literature, the indication list for motor cortex stimulation (MCS) includes poststroke pain, trigeminal neuropathic or deafferentation pain (TNP), brachial plexus avulsion, phantom limb pain, and various central and peripheral neuropathic pain syndromes.10-29 In the past 10 years, a number of new indications for invasive cortical stimulation were introduced for the treatment of tinnitus,30,31 epilepsy,32-34 stroke recovery,15,35,36 tremor,37,38 Parkinson disease,37-41 and depression.42-44
Although no comprehensive and reliable data on the worldwide use of MCS exist, one can assume that >700 patients with various chronic pain syndromes were treated with MCS.17,45-50 Because no standard protocol for this procedure exists, comparisons of the results of various centers are limited. One of the major indications for MCS is chronic, refractory neuropathic pain syndromes of the trigeminal nerve or facial areas. The pain either may be spontaneous or may occur after dental procedure, orofacial manipulations, or procedures in the paranasal sinuses. Additionally, trigeminal neuropathic pain may be a complication after nerve lesion of surgical procedures against trigeminal neuralgia (eg, rhizotomy or neurovascular decompression) or intracranial or extracranial tumors of the trigeminal nerve or surrounding structures (meningiomas, etc). In patients with TNP refractory to pharmacological, psychological, and conservative treatment options, the indication for MCS should be evaluated. Hence, we present a prospective, noncontrolled clinical trial of a single-center experience with a special focus on the operative approach and long-term follow-up.
From Clinical Significance of Invasive Motor Cortex Stimulation for Trigeminal Facial Neuropathic Pain Syndromes by Dirk Rasche and Volker M. Tronnier