Evidence-based pain medicine: the good, the bad, and the ugly

Validation of proposed diagnostic criteria (the "Budapest Criteria") for Complex Regional Pain Syndrome

Current IASP diagnostic criteria for CRPS have low specificity, potentially leading to overdiagnosis. This validation study compared current IASP diagnostic criteria for CRPS to proposed new diagnostic criteria (the "Budapest Criteria") regarding diagnostic accuracy. Structured evaluations of CRPS-related signs and symptoms were conducted in 113 CRPS-I and 47 non-CRPS neuropathic pain patients. Discriminating between diagnostic groups based on presence of signs or symptoms meeting IASP criteria showed high diagnostic sensitivity (1.00), but poor specificity (0.41), replicating prior work. In comparison, the Budapest clinical criteria retained the exceptional sensitivity of the IASP criteria (0.99), but greatly improved upon the specificity (0.68). As designed, the Budapest research criteria resulted in the highest specificity (0.79), again replicating prior work. Analyses indicated that inclusion of four distinct CRPS components in the Budapest Criteria contributed to enhanced specificity. Overall, results corroborate the validity of the Budapest Criteria and suggest they improve upon existing IASP diagnostic criteria for CRPS.

Clinical Research in Interventional Pain Management Techniques: The Clinician's Point of View

Interventional pain management techniques are considered for patients whose pain proves refractory to conventional treatment. According to the evidence-based medicine (EBM) guidelines, the highest level of evidence for efficacy and safety of a treatment is generated in high-quality randomized controlled trials and systematic reviews. A randomized controlled trial is defined as an experiment that determines the influence of an intervention on the natural history of the disease, which means that the comparative group should receive placebo, which is a sham intervention in case of the interventional pain management techniques. The systematic review summarizes in a structured way the results of the available information. When randomized controlled trials are available, observational studies will often be discarded. As new information on a treatment becomes available the perceived value may change, thus determining the survival time of clinical evidence. This survival time is not different when based on randomized or nonrandomized studies. The inclusion criteria are an important component of the randomized controlled trial and are designed to test a treatment in a homogeneous patient population. As interventional pain management techniques are mainly used for the management of spinal pain, it needs to be stressed that there is no gold standard for the diagnosis. This lack of validated standard diagnostic procedures is at the origin of different patient selection criteria, which makes the interpretation of the different randomized controlled trials and the meta-analyses very difficult. Moreover, the extrapolation of randomized controlled trials with carefully selected patient populations to daily practice is a major problem. Randomized controlled trials in interventional pain management techniques often prove to be underpowered, which can be attributed to the difficulty in motivating patients and the referring physicians to participate in a trial where there is 50% chance of receiving a placebo/sham for intractable pain. Furthermore, the validity of sham intervention as a reflection of the natural course of the disease is questioned. It is stated that any new technique should prove to be at least equally effective as the best available treatment option, which offers the possibility of comparing two groups, both receiving active treatment. The reference treatment may be pharmacological or a rehabilitation program (cognitive behavioral) in which case blinding becomes a problem. It has been demonstrated that large observational studies with a cohort or case-control design do not systematically overestimate the magnitude of the associations between exposure and outcome as compared with the results of randomized controlled trials. There is an urgent need for guidelines on performing prospective cohort trials that should be designed to confirm or refute the anecdotal findings from retrospective studies.

Complex Regional Pain Syndrome (CRPS): Survey of Current Practices

BACKGROUND AND OBJECTIVES

There are numerous treatments for complex regional pain syndrome (CRPS). These treatments are varied in scope and include pain management therapies, psychological therapies, and physiotherapy. Treatment guidelines have been published in the past, but little information exists as to how clinicians utilize these guidelines. Moreover, there has been a paradigm shift from the older "reflex sympathetic dystrophy" (RSD) nomenclature, with largely sympathetic block driven diagnosis and therapy to more recent trends towards more inclusive "CRPS" diagnostic criteria and multidisciplinary treatment. There remains controversy regarding the selection of various techniques, and the timing of advancement through the treatment algorithm to the more aggressive, interventional techniques. We set out to determine current CRPS treatment practices of interventional pain specialists.

METHODS

The authors developed a 36-item, 15-20-minute questionnaire. This questionnaire was sent to 453 interventional pain specialists.

RESULTS

One-hundred-five surveys were returned, with 100 being complete. Eighty-three percent of our respondents were practicing anesthesiology pain specialists who on average treat 14.9 (SD = 16.8) CRPS patients per month.

CONCLUSIONS

Our survey results revealed the use of a treatment algorithm for CRPS that consists of treatment using medical therapies (pharmacologic, blocks, catheters, and implantable devices), psychological therapies, and physiotherapy in a coordinated fashion. The trend among our survey respondents is to utilize increasingly interventional techniques after a failed 2- to 4-week trial of any one particular therapy.