Outcome predictors of platelet-rich plasma injection for moderate carpal tunnel syndrome.

INTRODUCTION Platelet-rich plasma (PRP) injection is effective for mild-to-moderate carpal tunnel syndrome (CTS), and physicians have been using PRP injections to treat CTS. However, the predictive factors of PRP injections have not been evaluated. This retrospective study sought to identify the predictive factors of PRP injections in patients with moderate CTS. METHODS Seventy-one patients with moderate CTS receiving single PRP injections were enrolled. The outcomes at the third- and sixth-month postinjection visits were categorised into good and poor groups according to the following: (1) good outcome, with visual analogue scale (VAS) score decrease ≧50% and (2) poor outcome, with VAS score decrease <50% of preinjection scores. Significant variables between groups were entered into a binary logistic regression to determine the predictive factors. RESULTS The baseline body weight (BW), distal motor latency (DML), sensory nerve conduction velocity (SNCV), and cross-sectional area (CSA) of the median nerve were significantly different between the groups in the third month. The odds ratios (ORs) of all features were significant, except for SNCV (BW, OR: 0.911; P = .016; DML, OR: 0.383; P = .028; CSA, OR: 0.694; P = .003), and they remained significant in the sixth month (BW, OR: 0.909; P = .004; DML, OR: 0.530; P = .011; CSA, OR: 0.828; P = .032). CONCLUSION Lower BW, DML, and CSA values of the median nerve predict better outcomes after perineural injection of PRP for moderate CTS at the 3- and 6-month follow-ups.