The objective of this study was to review literature systematically concerning effectiveness of nonsurgical interventions for treating carpal tunnel syndrome (CTS). A best-evidence synthesis was performed to summarize the results of the included studies. Two reviews and 20 RCTs were included. Strong and moderate evidence was found for the effectiveness of oral steroids, steroid injections, ultrasound, electromagnetic field therapy, nocturnal splinting, and the use of ergonomic keyboards compared with a standard keyboard, and traditional cupping versus heat pads in the short term. Also, moderate evidence was found for ultrasound in the midterm. With the exception of oral and steroid injections, no long-term results were reported for any of these treatments. No evidence was found for the effectiveness of oral steroids in long term. Moreover, although higher doses of steroid injections seem to be more effective in the midterm, the benefits of steroids injections were not maintained in the long term. For all other nonsurgical interventions studied, only limited or no evidence was found.
The reviewed evidence supports that a number of nonsurgical interventions benefit CTS in the short term, but there is sparse evidence on the midterm and long-term effectiveness of these interventions. Therefore, future studies should concentrate not only on short-term but also on midterm and long-term results.