Bilateral and idiopathic carpal tunnel syndrome: clinical functional features and effect of stretching and instrument-assisted soft tissue mobilisation: a randomised controlled crossover study

Background/Aims Clinical treatment is an option for mild to moderate carpal tunnel syndrome. However, there is limited high-quality evidence for the benefit of various exercise and mobilisation interventions. The aim of this study was to evaluate the effect of stretching and instrument-assisted soft tissue mobilisation in patients with mild and moderate idiopathic bilateral carpal tunnel syndrome, both during the therapy period and at a 6-month follow-up period. Methods A 2 × 4 randomised controlled crossover study was conducted with 30 participants using both objective (handgrip and digital pinch) and subjective (visual analogue scale, Boston Carpal Tunnel Questionnaire and 12-item Short Form Health Survey questionnaire (SF-12)) outcome variables. Participants were randomised to one of two sequences: stretching followed by instrument-assisted soft tissue mobilisation, or instrument-assisted soft tissue mobilisation followed by stretching. Each intervention was administered twice weekly for 4 weeks, with each session lasting approximately 45 minutes. A 1-week washout period occurred between the first and second intervention phases. Assessments were conducted at baseline, after each 4-week intervention block and at 3- and 6-month follow ups. Data analysis by an analysis of variance crossover allowed evaluating sequence, treatment, carryover and period components. Results The sequences used did not show significant differences for any outcome (P>0.05). When analysed in the first period (to exclude carryover effects), treatment with instrument-assisted soft tissue mobilisation showed a tendency for better performance in reducing pain (eg visual analogue scale right hand, Cohen's d=0.86 for instrument-assisted soft tissue mobilisation vs stretching) and improving digital pinch strength (eg tip inch right hand, Cohen's d=−1.00, favouring instrument-assisted soft tissue mobilisation). The analysis of variance crossover indicated statistically significant treatment effects for pain reduction in both hands (eg right hand: F=16.54, P<0.001; left hand: F=18.25, P<0.001). A significant period effect (P<0.01) was observed for all outcomes, with large effect sizes (eg for change from baseline to 6-month follow-up for visual analogue scale right hand Cohen's d=−4.36; hand grip right hand Cohen's d=3.03), with the exception of the SF-12 physical domain, which showed an intermediate effect size (Cohen's d=0.67). Conclusions Combined association of stretching and instrument-assisted soft tissue mobilisation proved to be both supplementary and effective with robust results both during the course of the applied therapies and at the 6-month follow-up period in patients with idiopathic bilateral carpal tunnel syndrome with mild and moderate impairment. Implications for practice Combined stretching and instrument-assisted soft tissue mobilisation is a viable and beneficial non-surgical treatment strategy. Clinicians can consider incorporating this treatment modality into their treatment programmes. The observed improvements in pain, strength, function and quality of life, which were largely sustained at the 6-month follow up, support its inclusion in clinical practice for carpal tunnel syndrome management.