Spinal cord stimulation a promising treatment for chronic pain syndromes

A recent report published in the Journal of Neurosurgery: Spine reviewed 20 years worth of literature on the safety and efficacy of spinal cord simulation (SCS) for the treatment of chronic neuropathic pain. Researchers found that although there is a limited amount of compressive, randomised research available, evidence tends to suggest that SCS has positive, symptomatic benefits for patients with chronic pain disorders of various aetiologies.

A report published in a 2004 issue of the Journal of Neurosurgery: Spine reviewed research conducted from 1981, on the long-term risks and benefits of spinal cord simulation (SCS) treatment fof chronic neuropathic pain of the trunk and limbs. This mode of treatment has been widely used for various pain disorders since its introduction by Shealy et al. in 1967. The precise mechanism of action for SCS is not understood but it adopts principals of electrode-induced electrical stimulation of the dorsal columns of the spinal cord. Electrodes can either be placed percutaneously into the epidural space or following laminectomy. In both cases the leads are connected to an external generator, radiofrequency receiver or implanted pulse generator to power the electrodes. Leads are inserted at the anatomical level of the spinal cord corresponding to the area of pain experienced in the trunk or limbs. This produces sufficient paraesthesia at the offending site.

Results of the report were based on 68 studies on the efficacy and 51 studies on safety of SCS that met the appropriate analysis selection criteria. This corresponded to information on 3679 and 2972 patients respectively. Data was extracted systematically from each of the relevfant studies and grouped according to the pain indication into back and leg pain studies (16 studies), Chronic Regional Pain Syndromes (12 studies), ischaemic pain (13 studies), angina pain (11 studies) and various pain diagnoses (18 studies). Although only a small number of positive prospective controlled trials were available, the pooled literature suggested that SCS caused long-term improvements in pain levels in refractory angina pain, severe ischemic limb pain secondary to peripheral vascular disease, peripheral neuropathic pain and chronic lower back pain. SCS is therefore considered an effective treatment for patients with chronic, non-malignant pain of neuropathic origin.

Furthermore, SCS was found to be a relatively safe treatment with the majority of complications being non-life-threatening and reversible following removal of the device. Lead migration was the most common complication and serious complications such as paralysis, infection, CSF leakage, allergic reactions and skin erosions were evident in only a small number of patients. In addition, milder side effects of headache, asthenia, dizziness, twitchiness and electrical interference were reported by some subjects in the studies. However, SCS presents favorably over alternate methods of chronic pain relief due to its reversibility and the lack of long term or systemic side effects. These are potential problems associated with ablative surgery and opioid medications respectively.

This report has potential therapeutic implications as it highlights a promising and safe therapy that can be employed by practitioners in the management of their large numbers of patients with chronic pain disorders. As this treatment targets mechanisms of pain sensation, it could be used in the treatment of a host of disorders. Unfortunately the results of this literature survey were not conclusive enough to suggest clinical practice guidelines due to the lack of controlled studies on SCS. Further randomised, controlled and long-term studies need to be conducted on large patient samples to confidently confirm the efficacy of this treatment. The feasibility of maintaining a control group and blinding participants will however be difficult.

Source

Cameron T. Safety and efficacy of spinal cord stimulation for the treatment of chronic pain: a 20-year literature review. J Neurosurg (Spine 3) 2004; 100: 254-67.