INTRODUCTION: Carpal tunnel syndrome (CTS) is a relatively common condition caused by
compression of one of the main nerves at the wrist, the median nerve. Non-surgical
treatments, like steroid injections and physiotherapy, are the first line of treatment for
patients with carpal tunnel syndrome. The investigators have previously shown that specific
physiotherapeutic exercises (neurodynamic exercises) can reduce the need for carpal tunnel
surgery in some patients. Experimental studies in animal models demonstrate that these
exercises have an anti-inflammatory effect and can help the nerve to regenerate. However, the
exact mechanisms of action of these exercises are not well understood in patients. A better
understanding of the mechanisms of action of physiotherapeutic exercises would help
clinicians to better target these treatments to those patients who may benefit from them.
AIM: To investigate the mechanisms of action of 6 weeks' neurodynamic treatments on nerve
function and structure as well as patient-reported outcome measures in patients with CTS
compared to a positive control intervention (routine care steroid injection) and a negative
control intervention (advice).
METHODS AND ANALYSIS: In this single-blind randomised mechanistic trial, patients with
confirmed mild to moderate CTS (n=78) and age and gender-matched healthy controls (n=30) will
be included. Patients will be randomly allocated to a 6-week neurodynamic exercise group,
steroid injection, or advice group. Outcome measures will be explored at baseline (patients
and controls), post-intervention (patients), and 6-month follow-up (patients). Outcomes
include diffusion-weighted and anatomical MRI of the median nerve at the wrist, quantitative
sensory testing, nerve conduction studies, inflammatory markers in blood and skin biopsies,
and validated questionnaires for pain, function, and psychological factors. Two-way repeated
measures ANCOVAs (factors time and intervention, adjusted for baseline measurements as a
continuous covariate) will be performed to identify differences in MRI parameters, clinical
assessment, and inflammatory markers between patients in different groups and healthy
controls.