Mike: Hello, I'm Mike Clarke, podcast editor for the Cochrane Library. For some health conditions, there are multiple Cochrane reviews, each looking at the effects of a different intervention. Overviews of reviews are intended to help users to consider all interventions together and one of these overviews, for treating pain and disability in adults with complex regional pain syndrome was updated in June 2023. Here's lead author, Michael Ferraro from Neuroscience Research Australia, to describe the findings.

Michael: Complex regional pain syndrome, or CRPS, is a disabling chronic pain condition. It normally occurs in a single hand or foot after fracture, trauma or surgery. People with CRPS experience severe and persistent pain in their limb, as well as symptoms such as swelling, discolouration, stiffness, and changes to skin, nail and hair growth. It has a significant impact on their lives and it's important to know how to effectively treat it.
A broad range of therapies are used for CRPS. These include drugs, medical procedures such as nerve blocks and implantation of nerve stimulators, physiotherapy and rehabilitation, and psychological therapies.
We have updated an overview of systematic reviews last published in 2013 to investigate the effects of these by looking at the relevant systematic reviews and the randomised controlled within them. We identified five Cochrane reviews and 12 non-Cochrane reviews, which summarised evidenced from a total of 127 randomised trials. This is almost double the amount of trial evidence that was in the previous version of this overview. The included trials evaluated a wide range of treatments, including drugs, medical procedures, rehabilitation, and complementary and alternative therapies. We assessed four of the five Cochrane reviews as high quality, while the non-Cochrane reviews were all low or critically low quality.
Turning to our findings, there was no high certainty evidence for any comparison.
We found low certainty evidence that, compared with placebo, bisphosphonates (a class of medicines that slow down bone loss) may reduce pain intensity shortly after treatment, but moderate certainty evidence that they are associated with an increased risk of side effects.
There was moderate certainty evidence that, compared with a sham treatment, blocking the branches of the sympathetic nervous system with an anaesthetic probably does not reduce pain intensity.
However, for most of the commonly used drug, surgical, rehabilitation, and complementary and alternative therapies for CRPS, we found only very low‐quality evidence or no evidence at all on their effects. As a result, we cannot be certain about their effects on pain and disability in CRPS.
In summary, despite a considerable increase in randomised trial evidence compared with the 2013 version of this overview, we have found no high certainty evidence for the effectiveness of any therapy for CRPS. Larger, high‐quality clinical trials are urgently needed so that CRPS can be managed using an evidence‐based approach. Additionally, current non‐Cochrane systematic reviews of interventions for CRPS are of insufficient quality to provide an accurate and comprehensive summary of the evidence.

Mike: To read the overview, and find out more about the five Cochrane and 12 non-Cochrane reviews that it included, you can find it online. If you go to Cochrane Library dot com and search 'CRPS overview', you'll see a link to it.