Efficacy of Shortwave Diathermy in Managing Discogenic Low Back Pain in Adults Protocol for a Two Arm Randomized Controlled Trial

Background: The additional benefit of shortwave diathermy alongside conventional physiotherapy remains uncertain for adults with discogenic low back pain. Previous studies have used heterogeneous treatment parameters and have methodological limitations. This ongoing trial evaluates the additional benefit of active shortwave diathermy compared with sham treatment when both groups receive the same conventional physiotherapy programme and home exercise advice. Methods: This is a two-centre, two-arm, parallel-group randomised controlled trial of adults aged 20–60 years with clinically diagnosed discogenic low back pain in Sirajganj, Bangladesh. Recruitment and randomisation took place from 1 June to 27 July 2026, and follow-up is ongoing. A total of 208 participants were recruited and randomised, with 104 allocated to active shortwave diathermy and 104 to sham treatment using a sex-stratified, computer-generated sequence and concealed allocation. The protocol specifies twelve sessions over four weeks. Active treatment uses a carrier frequency of 27.12 MHz for 20 minutes per session; the sham procedure delivers no therapeutic shortwave energy. Both groups receive the same conventional physiotherapy and home exercise advice. Assessments are scheduled at baseline and weeks 4, 12 and 24 after randomisation. The primary endpoint is pain intensity on a 10-cm visual analogue scale at week 4. Disability and safety are secondary outcomes; lumbar range of motion, psychological measures and satisfaction are exploratory outcomes. The design specifies blinded outcome assessors. Analyses will follow the intention-to-treat principle and report between-group estimates with 95% confidence intervals. No outcome results are reported in this protocol manuscript. Discussion: The trial will estimate the additional benefit and harms of active SWD within a shared rehabilitation programme, rather than the effectiveness of SWD used alone. Interpretation will account for diagnostic uncertainty, possible participant unblinding, adherence to supervised and home exercises, and additional care.