The efficacy of spinal cord stimulation for chronic pain

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

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.

Spinal Cord Stimulation in Chronic Pain: A Review of the Evidence

This review looks at the evidence for the effectiveness of spinal cord stimulation in various chronic pain states. Spinal cord stimulation can only be effective when appropriate dorsal column fibres in the spinal cord are preserved and able to be stimulated. Spinal cord stimulation has been shown to have little to offer for patients with some diagnoses. Although 50 to 60% of patients with failed back surgery syndrome obtain significant pain relief with this technique, the strength of the evidence available is insufficient to clearly advocate its use in all patients with this condition. Though limited in quantity and quality, better evidence exists for its use in neuropathic pain, complex regional pain syndrome, angina pectoris and critical limb ischaemia. There is a lack of high quality evidence relating to spinal cord stimulation due to difficulties in conducting randomized controlled trials in this area. Serious methodological problems are encountered in blinding, recruitment and assessment in nearly all published trials of spinal cord stimulation. Suggestions regarding appropriate methodologies for trials which would produce better quality evidence are summarized.

Spinal cord stimulation: Subjective pain intensity and presurgical correlates in chronic pain patients

OBJECTIVES

This study determined the changes in pain intensity prior to and after permanent placement of spinal cord stimulation (SCS), as measured by the Visual Analog Scale (VAS) and, examined associations of presurgical characteristics to both pre- and post-SCS VAS scores.

MATERIALS AND METHODS

Demographic, disease, and psychological data were extracted from the medical charts of chronic pain patients (N = 58) being treated at a Hospital in IL, USA. Most patients were diagnosed with complex regional pain syndrome (51.9%) and low back pain (33.3%). The majority were White (72.5%), male (60%), married (72%), and temporary disabled or receiving worker's compensation (40%). Study objectives were tested with correlational and univariate analysis.

RESULTS

A significant reduction between pre (M = 6.87; SD = 1.38) and Post-(M = 4.11; SD = 1.54) SCS pain intensity scores was observed (p < .000). Pre-SCS pain intensity scores were associated with medical diagnosis (p < .01), marital status (p < .05), and catastrophizing (p < .05). Post-SCS pain intensity scores were associated with body mass index (p < .05), medical diagnosis (p < .05), employment status (p < .05), bodily concern (p < .05), marital status (p < .05), and race (p < .05).

CONCLUSIONS

Results strengthen support for the short-term effectiveness of SCS and demonstrate the differential associations of presurgical factors on pain intensity.

WITHDRAWN: Spinal cord stimulation for chronic pain

This review is out of date and will not be updated. The content of the review may be of historical interest to readers.

The editorial group responsible for this previously published document have withdrawn it from publication.

Effect and safety of spinal cord stimulation for treatment of chronic pain caused by diabetic neuropathy

AIM

Spinal cord stimulation (SCS) has been shown effective as a therapy for different chronic painful conditions, but the effectiveness of this treatment for pain as a result of peripheral diabetic neuropathy is not well established. The primary objectives of this study were to evaluate the effect and safety of SCS for treatment of pain and the effects on microcirculatory blood flow in the affected areas in patients with refractory peripheral diabetic neuropathy.

METHOD

The study was designed as a prospective, open-label study. Data were collected during screening, at implant and at regular intervals, after initiation of therapy. Eleven diabetic patients with chronic pain in their lower limbs and no response to conventional treatment were studied. The SCS electrode was implanted in the thoracic epidural space. Neuropathic pain relief was assessed by Visual Analogue Scale (VAS) and microcirculatory skin perfusion was measured with Laser Doppler flowmetry.

RESULTS

Nine subjects had significant pain relief with the percutaneous electrical stimulator. Average pain score for all nine patients was 77 at baseline and 34 at 6 months after implantation. At the end of the study, eight of nine patients continued to experience significant pain relief and have been able to significantly reduce their pain medication. For six of them, the stimulator was the sole treatment for their neuropathic pain. No significant changes in microcirculatory perfusion were recorded.

CONCLUSION

Spinal cord stimulation offers an effective and safe therapy for chronic diabetic neuropathic pain.

Evidence-based clinical practice guidelines for interdisciplinary rehabilitation of chronic nonmalignant pain syndrome patients

This is an update to evidence-based practice guidelines for chronic nonmalignant pain syndrome patients first published in 1995 and revised in 1999. The current guidelines recommend interdisciplinary-focused rehabilitation, which is goal-directed and time-limited. Emphasis is placed on educating patients in active self-management techniques that stress maximizing function. Integrated treatment involving medical, psychological/behavioral, physical/occupational therapy, and disability/vocational interventions are recommended on an outpatient basis whenever clinically possible. Patient selection criteria are delineated. Updated references providing evidence-based support for the recommendations are provided, including the use of opioids and sedative-hypnotic medications, injection and block procedures, acupuncture, implantable spinal infusion and stimulation devices, and other invasive spinal surgery procedures such as intradiscal electrothermal therapy. Guideline integration and early detection and intervention with chronic pain syndrome patients are encouraged.

Spinal cord stimulation for chronic back and leg pain and failed back surgery syndrome: a systematic review and analysis of prognostic factors

STUDY DESIGN

Systematic review.

OBJECTIVES

To assess efficacy and safety of spinal cord stimulation in patients with chronic leg and back pain and failed back surgery syndrome and to examine prognostic factors that predict spinal cord stimulation outcome.

SUMMARY OF BACKGROUND DATA

A previous systematic review of spinal cord stimulation in patients with chronic back and leg pain and failed back surgery syndrome by Turner et al in 1995 identified 39 case studies and no controlled studies.

METHODS

A number of electronic databases were searched through January 2002. Citation searching of included papers was undertaken, and gray literature was sought through contact with clinical experts. No language restrictions were applied. All controlled and noncontrolled study designs were included. Study selection was carried out independently by two reviewers. Prognostic factors (age, sex, duration of pain, time post surgery, follow-up duration, publication year, data collection year, indication, data collection country, study setting, and quality score) responsible for pain relief outcome across case series were examined using univariate and multivariate metaregression.

RESULTS

One randomized controlled trial, one cohort study, and 72 case studies were included. The randomized controlled trial reported a significant benefit (P = 0.047) in the proportion of patients with failed back surgery syndrome reporting 50% or more pain relief with spinal cord stimulation (37.5%) compared with patients undergoing back reoperation (11.5%). There was evidence of substantial statistical heterogeneity (P < 0.0001) in the level of pain relief following spinal cord stimulation reported across case series studies. The four principal prognostic factors found to be predictive of increased level of pain relief with spinal cord stimulation were poor study quality score, short follow-up duration, multicenter (versus single center) studies, and the inclusion of patients with failed back surgery syndrome (versus chronic back and leg pain). Overall, 43% of patients with chronic back and leg pain/failed back surgery syndrome experienced one or more complications following a spinal cord stimulation implant, although no major adverse events were reported.

CONCLUSIONS

Despite an increase in the number of studies over the last 10 years, the level of evidence for the efficacy of spinal cord stimulation in chronic back and leg pain/failed back surgery syndrome remains "moderate." Prognostic factors found to be predictive of the level of pain relief following spinal cord stimulation were study quality, follow-up duration, study setting, and patient indication.

Spinal cord stimulation for patients with failed back surgery syndrome or complex regional pain syndrome: a systematic review of effectiveness and complications

We conducted a systematic review of the literature on the effectiveness of spinal cord stimulation (SCS) in relieving pain and improving functioning for patients with failed back surgery syndrome and complex regional pain syndrome (CRPS). We also reviewed SCS complications. Literature searches yielded 583 articles, of which seven met the inclusion criteria for the review of SCS effectiveness, and 15 others met the criteria only for the review of SCS complications. Two authors independently extracted data from each article, and then resolved discrepancies by discussion. We identified only one randomized trial, which found that physical therapy (PT) plus SCS, compared with PT alone, had a statistically significant but clinically modest effect at 6 and 12 months in relieving pain among patients with CRPS. Similarly, six other studies of much lower methodological quality suggest mild to moderate improvement in pain with SCS. Pain relief with SCS appears to decrease over time. The one randomized trial suggested no benefits of SCS in improving patient functioning. Although life-threatening complications with SCS are rare, other adverse events are frequent. On average, 34% of patients who received a stimulator had an adverse occurrence. We conclude with suggestions for methodologically stronger studies to provide more definitive data regarding the effectiveness of SCS in relieving pain and improving functioning, short- and long-term, among patients with chronic pain syndromes.

Safety and efficacy of spinal cord stimulation for the treatment of chronic pain: a 20-year literature review

OBJECT

The purpose of this report was to examine the available literature to determine the safety and efficacy of spinal cord stimulation (SCS) for the treatment of chronic pain of the trunk and limbs.

METHODS

The author identified 68 studies that fulfilled the efficacy inclusion/exclusion criteria, grouped on the basis of pain indication, with an overall population of 3679 patients. Fifty-one studies fulfilled all safety inclusion/exclusion criteria. Based on the literature review, the author found that SCS had a positive, symptomatic, long-term effect in cases of refractory angina pain, severe ischemic limb pain secondary to peripheral vascular disease, peripheral neuropathic pain, and chronic low-back pain, and that, in general, SCS was a safe and effective treatment for a variety of chronic neuropathic conditions.

CONCLUSIONS

Despite the positive findings, there is an urgent need for randomized, controlled, long-term studies on the efficacy of SCS involving larger patient sample sizes.

Spinal cord stimulation for chronic pain

BACKGROUND

Spinal cord stimulation (SCS) is a form of therapy used to treat certain types of chronic pain. It involves an electrical generator that delivers pulses to a targeted spinal cord area. The leads can be implanted by laminectomy or percutaneously and the source of power is supplied by an implanted battery or by an external radio-frequency transmitter. The exact mechanism of action of SCS is poorly understood.

OBJECTIVES

To assess the efficacy and effectiveness of spinal cord stimulation in relieving certain kinds of pain, as well as the complications and adverse effects of this procedure.

SEARCH STRATEGY

We searched MEDLINE and EMBASE to September 2003; the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 3, 2003); textbooks and reference lists in retrieved articles. We also contacted experts in the field of pain and the main manufacturer of the stimulators.

SELECTION CRITERIA

We included trials with a control group, either randomized controlled trials (RCTs) or non-randomized controlled clinical trials (CCTs), that assessed spinal cord stimulation for chronic pain.

DATA COLLECTION AND ANALYSIS

Two independent reviewers selected the studies, assessed study quality and extracted the data. One of the assessors of methodological quality was blinded to authors, dates and journals. The data were analysed using qualitative methods (best evidence synthesis).

MAIN RESULTS

Two RCTs (81 patients in total) met our inclusion criteria. One was judged as being of high quality (score of 3 on Jadad scale) and the other of low quality (score of 1 on Jadad scale). One trial included patients with Complex Regional Pain Syndrome Type I (reflex sympathetic dystrophy) and the other patients with Failed Back Surgery Syndrome. The follow-up periods varied from 6 to 12 months. Both studies reported that SCS was effective, however, meta-analysis was not undertaken because of the small number of patients and the heterogeneity of the study population.

REVIEWERS' CONCLUSIONS

Although there is limited evidence in favour of SCS for Failed Back Surgery Syndrome and Complex Regional Pain Syndrome Type I, more trials are needed to confirm whether SCS is an effective treatment for certain types of chronic pain. In addition, there needs to be a debate about trial designs that will provide the best evidence for assessing this type of intervention.