Photobiomodulation for Median Nerve Neuroplasticity in Carpal Tunnel Syndrome: A Randomized Controlled Trial

Summary

Carpal Tunnel Syndrome (CTS) is the most common peripheral entrapment neuropathy, causing pain, paresthesia, and hand dysfunction due to median nerve compression at the wrist. While physiotherapy provides symptom relief, it does not effectively address the underlying neuroplastic deficits of the median nerve. Photobiomodulation (PBM), delivered at 830 nm near-infrared wavelength, has shown potential to enhance peripheral nerve regeneration via cytochrome c oxidase activation, ATP synthesis, and upregulation of neurotrophic factors including brain-derived neurotrophic factor (BDNF). This randomized controlled trial will evaluate whether 830 nm PBM (200 mW, 4 J/cm², 12 sessions over 4 weeks) combined with routine physiotherapy produces significantly greater neuroplastic recovery of the median nerve - assessed by high-resolution ultrasound (HRUS) measurement of median nerve cross-sectional area (CSA), nerve conduction study parameters and serum BDNF - compared to sham PBM combined with identical physiotherapy in adults with mild-to-moderate CTS. Neuroplasticity was operationalised as a multimodal construct comprising: (1) functional recovery, indexed by nerve conduction study parameters; (2) structural remodelling, indexed by median nerve cross-sectional area on high-resolution ultrasound; and (3) molecular neuroplastic signalling, indexed by serum BDNF. This multimodal approach was adopted because no single measure captures the full construct of peripheral nerve neuroplasticity (Padua et al., 2020).

Conditions

• Carpal Tunnel Syndrome (CTS)

Interventions

DEVICE

Photobiomodulation (Low-Level Laser Therapy)

Photobiomodulation (PBM) delivered using a 46-diode cluster probe at 830 nm wavelength, 200 mW optical output power, continuous wave mode, 4 J/cm² energy density, applied in static contact technique over the carpal tunnel (volar wrist surface, 3-5 cm proximal to distal wrist crease). Application time per session: approximately 200 seconds (\~3.3 minutes). Treatment schedule: 3 sessions per week for 4 consecutive weeks (12 sessions total). Sham device output confirmed \<1 mW by calibrated photodiode power meter.

DEVICE

Sham Photobiomodulation

Deactivated PBM device identical in external appearance to the active device. Applied using the same 46-diode cluster probe, contact technique, and duration (approximately 200 seconds) as the active arm. Output power confirmed \<1 mW by calibrated photodiode power meter (LaserCheck or equivalent) at baseline, session 6, and session 12 for the first five enrolled participants. No therapeutic light emission occurs.

OTHER

Routine Physiotherapy Programme

Participants will receive an 4-week routine physiotherapy programme comprising median nerve mobilization, night splinting, and tendon-gliding exercises. Median nerve mobilization will use six sequential positions progressing from wrist-neutral finger/thumb flexion to finger, wrist, and thumb extension, forearm supination, and assisted thumb stretching. Each position will be held for 5 seconds; the sequence will be repeated 10 times, three times daily. A neutral volar wrist splint allowing free finger and thumb movement will be worn nightly for 6-8 hours. Tendon-gliding exercises will include straight hand, hook fist, full fist, tabletop, and straight fist positions. Each position will be held for 5 seconds, with 10 repetitions performed three times daily. A physiotherapist will teach and monitor the programme. Participants will receive illustrated instructions and maintain an adherence diary. Exercises will be modified or stopped if symptoms worsen.

Sponsors & Collaborators

• University of Lahore

  lead OTHER

Principal Investigators

• Dr Sajid Mehmood, MS (OMPT) · University of Lahore

• Dr Ashfaq Ahmad, PhD · University of Lahore

• Dr Umair Ahmed, PhD · University of Lahore

• Dr Ishaq Ahmed, PhD · University of Lahore

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

60 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2026-08-15

Primary Completion

2027-05-15

Completion

2027-08-15

Countries

• Pakistan

Study Locations