The Effect of Ketamine Infusion in the Treatment of Complex Regional Pain Syndrome: a Systemic Review and Meta-analysis

  • Jianli Zhao
  • Yajing Wang
  • Dajie WangEmail author
Hot Topics in Pain and Headache (N Rosen, Section Editor)
Part of the following topical collections:
  1. Topical Collection on Hot Topics in Pain and Headache


Purpose of Review

Complex regional pain syndrome (CRPS) is a painful debilitating neurological condition that accounts for approximately 1.2% of adult chronic pain population. Ketamine, an NMDA receptor antagonist, is an anesthetic agent that has been used by some pain specialists for CRPS. There is a growing body of clinical evidence to support the use of ketamine in the treatment of neuropathic pain, especially CRPS. This meta-analysis study was aimed to examine the efficacy of ketamine in the treatment of CRPS.

Recent Findings

A search of Embase, Pubmed, Web of Knowledge, Cochrane, Clinical, and between Jan 1, 1950, and August 1, 2017, was conducted to evaluate ketamine infusion therapy in the treatment of CRPS. We selected randomized clinical trials or cohort studies for meta-analyses. I 2 index estimates were calculated to test for variability and heterogeneity across the included studies. The primary outcome is pain relief. The effect of ketamine treatment for complex regional pain syndrome was assessed by 0–10 scale numerical rating pain score. The secondary outcome is the pain relief event rate, which is defined as the percentage of participants who achieved 30% or higher pain relief in each of the qualified studies. Our meta-analysis results showed that the Ketamine treatment led to a decreased mean of pain score in comparison to the self-controlled baseline (p < 0.000001). However, there is a statistical significance of between-study heterogeneity. The immediate pain relief event rate was 69% (95% confidence interval (CI) 53%, 84%). The pain relief event rate at the 1–3 months follow-ups was 58% (95% CI 41%, 75%).


The current available studies regarding ketamine infusion for CRPS were reviewed, and meta-analyses were conducted to evaluate the efficacy of ketamine infusion in the treatment of CRPS. Our findings suggested that ketamine infusion can provide clinically effective pain relief in short term for less than 3 months. However, because of the high heterogeneity of the included studies and publication bias, additional random controlled trials and standardized multicenter studies are needed to confirm this conclusion. Furthermore, studies are needed to prove long-term efficacy of ketamine infusion in the treatment of CRPS.


Ketamine Ketamine infusion CRPS Complex regional pain syndrome RSD Reflex sympathetic dystrophy Causalgia 


Compliance with Ethical Standards

Conflict of Interest

Jianli Zhao, Yajing Wang, and Dajie Wang declare no conflict of interest.

Human and Animal Rights and Informed Consent

This article does not contain any studies with human or animal subjects performed by any of the authors.


Papers of particular interest, published recently, have been highlighted as: • Of importance •• Of major importance

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© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Emergency MedicineThomas Jefferson UniversityPhiladelphiaUSA
  2. 2.Department of AnesthesiologyShanxi Medical UniversityTaiyuanChina
  3. 3.Jefferson Pain Center, Department of AnesthesiologyThomas Jefferson UniversityPhiladelphiaUSA

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