Predictors of Long-Term Outcome of Thoracic Sympathectomy in Patients with Complex Regional Pain Syndrome Type 2.

Background and Objective Long-term results of sympathectomy in patients with complex regional pain syndrome (CRPS) type 2 varies widely among studies due to nonspecific or vague criteria of diagnosis and absence of outcome predictors that help good patient selection. The objective was to determine the predictors of long-term outcome of sympathectomy in patients with upper limb CRPS type 2. Methods A retrospective cohort, in which those who underwent thoracic sympathectomy for upper limb CRPS type 2 from 2007 to 2014, were included. Demographic and clinical data of patients, in addition to stellate ganglion block (SGB) details and percent of pain relief at the end of follow-up, were collected and used for statistical analysis. Results Our study included 53 patients, with a mean age of 47 ± 7 years, and 60% females. Using bivariate correlations; age, sex, nerve injured, type of injury, and occupation were not significantly correlated to outcome. Multiple linear regression analysis of correlated variables revealed that duration of pain relief after SGB and degree of sympathetic overactivity were positive predictors (β = 0.286, P  = 0.027, and β = 0.257, P  = 0.003, respectively), whereas presence of allodynia was a negative predictor (β = −0.280, P  = 0.041) of the final pain relief. Final pain relief was better in those patients who experienced extended relief of their pain >2 days after SGB ( P  = 0.001, Kruskal Wallis test). Conclusions Thoracic sympathectomy may prove more effective than reported in carefully selected CRPS patients with prominent sympathetic overactivity, no or early allodynia, and pain relief >2 days after SGB.