Objective: To assess the evidence for the safety and efficacy of invasive procedures for reducing chronic pain and improving function and health-related quality of life compared with sham (placebo) procedures.
Design: Systematic review with meta-analysis.
Methods: Studies were identified by searching multiple electronic databases, examining reference lists, and communicating with experts. Randomized controlled trials comparing invasive procedures with identical but otherwise sham procedures for chronic pain conditions were selected. Three authors independently extracted and described study characteristics and assessed Cochrane risk of bias. Two subsets of data on back and knee pain, respectively, were pooled using random-effects meta-analysis. Overall quality of the literature was assessed through Grading of Recommendations, Assessment, Development, and Evaluation.
Results: Twenty-five trials (2,000 participants) were included in the review assessing the effect of invasive procedures over sham. Conditions included low back (N = 7 trials), arthritis (4), angina (4), abdominal pain (3), endometriosis (3), biliary colic (2), and migraine (2). Thirteen trials (52%) reported an adequate concealment of allocation. Fourteen studies (56%) reported on adverse events. Of these, the risk of any adverse event was significantly higher for invasive procedures (12%) than sham procedures (4%; risk difference = 0.05, 95% confidence interval [CI] = 0.01 to 0.09, P = 0.01, I2 = 65%). In the two meta-analysis subsets, the standardized mean difference for reduction of low back pain in seven studies (N = 445) was 0.18 (95% CI = -0.14 to 0.51, P = 0.26, I2 = 62%), and for knee pain in three studies (N = 496) it was 0.04 (95% CI = -0.11 to 0.19, P = 0.63, I2 = 36%). The relative contribution of within-group improvement in sham treatments accounted for 87% of the effect compared with active treatment across all conditions.
Conclusions: There is little evidence for the specific efficacy beyond sham for invasive procedures in chronic pain. A moderate amount of evidence does not support the use of invasive procedures as compared with sham procedures for patients with chronic back or knee pain. Given their high cost and safety concerns, more rigorous studies are required before invasive procedures are routinely used for patients with chronic pain.
In the USA, doctors in the specialty of neurology would refer patients with chronic low-back pain to a specialist in either the fields of pain medicine or physical medicine and rehabilitation. Most of these patients are seen by a neurologist only once or twice, often with electromyography.
This analysis reviewed numerous different invasive procedures for numerous diagnoses. So, for any given pain condition, the number of patients studied was very small. Not unexpectedly, there is little to no robust data to support using several invasive interventions to treat chronic pain conditions.
Because the interventions are quite different, it is unclear what is to be learnt from a meta-analysis of studies of vastly different interventions.
Tradition is ancient error.
A well written and timely article. Most clinicians are unaware of the lack of evidence regarding invasive procedures for patients who are disabled by pain, or who are inappropriately treated with opiates. I enjoyed reading this article and will inform my colleagues.
I thought the premise of the article was interesting. Chronic pain is a heterogeneous entity caused by many different pathologies, so it is unlikely the question posed in the article could be answered with any level of confidence.
As practitioners who deal with arthritic conditions, this information is useful to educate and inform my patients. A caveat is whether there are small subsets of patients in whom these procedures might offer benefit.
This meta-analysis (MA) found little support for invasive procedures for pain. The MA was very well described by the authors who acknowledge the limitations including that there were few studies on any one condition and the difficulty with conducting sham trials.