There are many other CRPS treatments that are fairly new or are not used very often due to reasons such as funding issues, availability, and other contributing factors. Such treatments are:
A form of treatment often used in patients who have MS. There are actually very few centres with HBOT in the UK. However, there have been several studies done that discuss the use of HBOT with patients who have chronic pain, including CRPS patients, but very few in the last few years. Unfortunately, there is simply not enough research into the use of HBOT for CRPS patients and it is still unknown as to whether it would help with pain and oedema / swelling. You would lie down in the chamber which has pressurised air and the treatment would in effect give your body more oxygen, i.e. in all your tissues and organs. You would be breathing 100% oxygen at a higher than normal atmospheric pressure, whereas the usual air we breathe everyday has around 21% oxygen. In the study by Kiralp, M.Z. et al. (2004), they found that:
"….significant decrease in the wrist circumference (due to decreased oedema) was observed between groups, between the end of treatment (after session 15) and day 45…"
IVIG has recently been studied by the noted consultant and researcher Dr Andreas Goebel, along with other professionals. A recent study in 2014 ('Immunoglobulin G for the Treatment of Chronic Pain: Report of an Expert Workshop' Pain Medicine) looked at the trial of only 13 patients who had been diagnosed with CRPS and had not responded to other treatment. The end result was that those who had been given the IVIG had found that there was a decrease in their pain scores. See also Tamburin, S. et al. (2014).
There was also a much larger trial on Low-Dose Immunoglobulin (aka LIPS trial), the results of which can be viewed here: Low-dose intravenous immunoglobulin treatment for complex regional pain syndrome (LIPS): study protocol for a randomized controlled trial.
Unfortunately, the research study into IVIG for long-standing Complex Regional Pain Syndrome (CRPS) by Goebel, A. et al (2017) did fail and patients weren't able to tell the difference between the placebo and the actual drug itself (Goebel, A. et al 2017).
Bisphosphonates (BPs) are potent inhibitors of osteoclastic activity widely used for the management of osteoporosis and other metabolic bone diseases. There have been a couple of trials of BPs, such as the Neridronate in 2013 (Gatti, D. et al 2013) and also a variety of BPs in 2015 (Giusti, A. & Bianchi, G. 2015).
It was found in a placebo controlled trial by Varenna, M. et al (2013) that aminobisphosphonate neridronate shows significant benefits in patients with CRPS. In this trial in CRPS, aminobisphosphonates seem to be most effective in high doses. Two 100 mg doses of neridronate were given intravenously four times over 10 days, estimated to be equivalent to pamidronate at 90mg given four times over 4–10 days. The results were that ≥50% reduction of the pain VAS score was seen in 73% of patients in the neridronate group versus 32% in the placebo group.
In some patients ketamine has been used to treat CRPS pain where other treatments have not be successful. This drug is actually an anaesthetic and there have been studies where patients with CRPS were given ketamine in low doses intravenously for a few days. They then find that there is either an elimination of the pain or substantial reduction. However, the specialists have not recommended ketamine for many people as the drug can induce what is known as Ketamine Bladder. This is where your bladder is totally affected by the drug and cause serious harm. According to Connolly, S. et al. (2015),
"There is no high quality evidence available evaluating the efficacy of ketamine for CRPS and all manuscripts examined in this review were of moderate to low quality. Therefore, we conclude there is currently only weak evidence supporting the efficacy of ketamine for CRPS…"