Spinal Cord Stimulation for Chronic Refractory Neuropathic Pain: A Technical Note Initial Experience of Two cases

Abstract

Spinal cord stimulation is an established procedure for relieving chronic neuropathic pain conditions. Although it has been over five decades since the first spinal cord stimulation (SCS) was developed, it has only been used in a few cases in India. It is primarily based on the “Gate Theory” of pain. The mechanism of its action is not exactly clear, but reports have suggested that it plays the main role in selectively stimulating the large diameter pain fibers in the dorsal aspect of spinal cord. SCS procedure involves a very careful case selection, and current evidence suggests that only a few conditions of chronic refractory neuropathic pain are its established indications. In these patients too, the efficacy rate remains around 50 to 75%. The overall pain relief observed is around 50% decrease in visual analog scale (VAS) scores. It is a technically simple procedure involving placement of electrodes over the dorsal aspect of spinal cord in the epidural space. The procedure is a staged one in which trial lead electrodes are first implanted and stimulated with an external pulse generator (EPG). If the trial is successful and patient has acceptable pain relief over 1 week of stimulation at various settings, the patient undergoes the permanent implantation of electrodes at the same position. The permanent electrodes are then stimulated by an implantable pulse generator (IPG) in the subcutaneous pocket (abdominal or gluteal). Complications are rare and are more related to hardware like lead migration and breakage. Since it is does not damage the cord per se, its acceptance as a procedure for pain is known quite well in the Western world. Its availability and cost of implants is the major hurdle in its use in a developing nation like India. Here, we present a technical note and our experience of two cases of thoracic spinal cord stimulation for chronic neuropathic pain at our institution.

Keywords

• spinal cord stimulator
• lead electrodes
• paddle electrodes
• implantable pulse generator
• trial stimulation
• permanent stimulation