Spinal Cord Stimulation; Indications and Challenges

Spinal cord stimulation (SCS) is a form of neuromodulation therapy aimed at treating spinal mediated pain. This treatment option is a minimally invasive, and is not neurodestructive method. Its effects are easily reversible, and there are no limitations to future therapy. Patients in whom medical therapy has failed and who have spinal pain that is refractory to preventive medication may benefit from spinal cord stimulation. Surgical modalities for treating the spinal pain are reserved as a last resort after failure of medical and interventional management. The theory of neuromodulation refers to therapeutic alteration of activity, electrically or chemically, in the central, peripheral, or autonomic nervous systems via the process of inhibition, stimulation, modification, or other forms of regulation. Spinal cord stimulation is standard treatment for refractory chronic pain (back and limbs) who have not respond to other treatments. Furthermore, the benefits of SCS have been described in a number of conditions, including: failed back surgery syndrome (FBSS), chronic radicular pain (cervical and lumbar), complex regional pain syndrome (CRPS), diabetic neuropathic pain, refractory angina pectoris, painful ischemic peripheral vascular disease (Raynaud, Berger). Patient selection is critical for producing acceptable outcomes. A device in proper location with appropriate programming will not be helpful if patient is not good candidate for therapy, and disease process does not respond to SCS.Spinal cord stimulation is a non-ablative procedure and involves an implantable device composed of electrode(s) and pulse generator. Prior to permanent implantation, a trial is performed under sedation in which leads are placed into the epidural space and are connected to an external battery. A permanent device is implanted only if the patient reports significant improvements in pain (more than 50% pain relief) and in quality of life during trial period (1-2 weeks). The lead is placed into the epidural space, and the pulse generator is implanted into a subcutaneous pocket in the abdomen, or back. The permanent implantation is placed under sedation or general anesthesia. New devices as wireless electrode are available, and have some benefit compare to traditional electrodes. Several studies with long-term follow-up (> 10 years) demonstrate that approximately 75% of patients rated either good or excellent long-term pain relief. SCS significantly reduced opiate intake compared to re-operation, and was more effective than re-operation for persistent radicular pain after spine surgery, and in great majority of patients obviated need for re-operation. SCS success requires: 1) right patient, 2) right equipment, and 3) right technique. Furthermore, there are some new potential applications for neurostimulation other than pain such as: motor dysfunction, congestive heart failure, peripheral vascular disease, respiratory over-reactive airway disease, obesity, Alzheimer’s disease, obsessive compulsive disorder, traumatic brain injury, addiction, and aggressive behavior.