Low-level laser therapy for carpal tunnel syndrome: systematic review and network meta-analysis

Splinting is recommended by various organisations as a non-surgical first-line treatment for carpal tunnel syndrome (CTS), despite the limited evidence supporting its effectiveness. Previous studies on the effectiveness of low-level laser therapy (LLLT) have reported mixed results, and this systematic review aimed to resolve this controversy.

To perform a network meta-analysis (NMA) for evaluating the effectiveness of LLLT compared with other conservative treatments for CTS.

Eighteen electronic databases were searched for potential randomised controlled trials (RCTs). RCTs evaluating LLLT or other non-surgical treatments as an add-on to splinting were included. Included RCTs measured at least one of the following three outcomes with validated instruments: pain, symptom severity and functional status.

Six RCTs (418 patients) were included. NMA suggested that LLLT plus splinting has the highest probability (75%) of pain reduction, compared with sham laser plus splinting (61%), ultrasound plus splinting (57%) and splinting alone (8%). However, while LLLT plus splinting is significantly more effective than sham laser plus splinting for pain reduction, the magnitude is not clinically significant (Visual Analogue Scale mean difference -0.53cm, 95% confidence interval -1.01 to -0.05cm; P=0.03, I²=25%). The effect of LLLT plus splinting on symptom severity and functional status was not superior to splinting alone.

The use of LLLT in addition to splinting for the management of CTS is not recommended, as LLLT offers limited additional benefits over splining alone in terms of pain reduction, reduction of symptom severity or improved functional status. PROSPERO for systematic reviews and meta-analyses registration number CRD42017082650.