A Novel Treatment Approach to Complex Regional Pain Syndrome (CRPS): A Feasibility Study of Combined Peripheral Nerve Block and Physiotherapy

Chronic pain is a debilitating condition affecting 1 in 5 Canadians with a yearly economic cost of over $40 billion in healthcare spending and loss of productivity. Since the prevalence of chronic pain is increasing, especially as the population ages, effective low-cost treatment is key to reduce the impact of chronic pain on patient quality of life and on healthcare costs. Due to the complexity of chronic pain and differences between the multitudes of pain conditions, developing effective treatments is challenging. This is especially true for Complex Regional Pain Syndrome (CRPS).

CRPS is characterized by severe pain out of proportion to tissue trauma, with local autonomic and inflammatory changes. The severity of pain from CRPS may result in an inability to work, depression, sleep disorders, or suicidal ideation.

Although its prevalence is low in Canada, CRPS is considered one the most debilitating and least understood pain conditions. As most current treatment options have low evidence of effectiveness, there is no definitive treatment available and most often, patients are struggling to maintain an acceptable quality of life. Thus, there is a pressing need to identify new and improved treatments for adults with CRPS.

An early hypothesis of CRPS pathophysiology posited that sympathetic nervous system over-activity led to many of the signs and symptoms of CRPS. As such, sympathetic nerve blocks, including stellate ganglion and lumbar sympathetic blocks, have been repeatedly investigated as a potential treatment of CRPS. However, a recent meta-analysis suggests that these blocks provided no benefits for those suffering with CRPS. Newer evidence suggests that a peripheral microvascular dysfunction may underlie CRPS pathophysiology. However, no clinical trials have investigated the efficacy of a treatment targeting this peripheral pathway. Current evidence of the efficacy of peripheral nerve block in treating CRPS are mostly derived from small case studies involving cost- and labour-intense regimens, including in-patient protocols with continuous nerve blocks.

The goal of this project is to assess the efficacy of a single-shot axillary brachial plexus block plus physiotherapy as a novel treatment protocol for CRPS. Our primary hypothesis is that providing a brachial plexus block in conjunction with a physiotherapy program would be superior to physiotherapy alone in treating pain and function in CRPS. Since this is a novel treatment protocol for CRPS, the purpose of our proposed study is to determine the feasibility of conducting a fully powered clinical trial. The specific aims of the feasibility trial are to assess: 1) the capacity (recruitment and staffing) required for conducting a fully powered trial, 2) the design of the novel treatment protocol, and 3) the patient response to treatment and trial protocol.