IMpact of Perineural Hydrodissection Over Alternative Therapies in Patients With Carpal Tunnel Syndrome (IMPACTS)

IMpact of Perineural Hydrodissection Over Alternative Therapies in Patients With Carpal Tunnel Syndrome

IMpact of Perineural Hydrodissection Over Alternative Therapies in Patients With Carpal Tunnel Syndrome (IMPACTS): A Single-Centre, Randomized Trial Comparing Perineural Hydrodissection of the Median Nerve Versus Steroid Injection in Patients With Carpal Tunnel Syndrome

This is a multidisciplinary, single-blinded, three-arm randomized controlled trial, comparing perineural hydrodissection and steroid injection for the treatment of CTS. Patients are screened based on pre-established eligibility criteria and randomized to one of the three study groups. Patients are followed at 6-week, 3-month, 6-month, and 12-month time points to assess the primary and secondary outcomes of the study, which include both patient-reported outcome measures and objective clinical assessments.

This study aims to examine the effect of perineural hydrodissection (PNH), a novel treatment for CTS. PNH is a minimally invasive, ultrasound-guided, percutaneous technique in which the median nerve is released by injecting fluid (local anesthetic and corticosteroid) circumferentially, using larger fluid volumes and higher pressure to target areas of adhesion between the median nerve and its surrounding structures. In chronic CTS, a rind of perineural fibrosis develops, tethering the median nerve to the overlying flexor retinaculum and to the adjacent flexor tendons. Theoretically, the removal of tethering to adjacent structures, via perineural hydrodissection, should allow circumferential bathing of the median nerve with the local anesthetic and corticosteroid, thus reducing inflammation and prolonging symptom relief. The primary outcome is pain as measured by the Boston Carpal Tunnel Questionnaire (BCTQ). Secondary outcomes include health-related quality of life measures using the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire and the Visual Analog Scale (VAS) for pain. The selected questionnaires have been shown to correlate well with domains of the International Classification of Functioning, Disability, and Health (ICF) (3). Other secondary measures include the ultrasound appearance (cross-sectional index) of the median nerve, and electromyography (EMG) measurements (including sensory and motor conduction velocities, and amplitudes), before and after the injection. The study hypothesis is that PNH will show greater benefits in terms of pain, function, and patient quality of life when compared to corticosteroid injection in patients with CTS. The null hypothesis is that there is no difference. The study is powered to address the primary outcome and will also be powered to identify minimally important differences in functional, sonographic, and electromyographic outcomes.

Care provider is performing a specific type of injection and therefore cannot be blinded. Those investigators responsible for collecting, managing, and analyzing data will be blinded to treatment randomization.

Patients in this group will undergo an injection of corticosteroid into the carpal tunnel as per current treatment practices.

Patients in this group will undergo a perineural hydrodissection plus an injection of corticosteroid into the carpal tunnel, as a novel technique.

The subcutaneous tissues of the ulnar aspect of the wrist at the level of the carpal tunnel will be infiltrated with 2 ml of lidocaine 1% for local anesthetic. Using ultrasound guidance and aseptic technique, the needle will then be angled deep to the median nerve within the carpal tunnel, and 5 ml of a 50%/50% mixture of lidocaine 1% and sensorcaine 0.5% will be injected under pressure. While continuing to use ultrasound guidance and aseptic technique, the needle will then be angled superficial to the median nerve within the carpal tunnel, and 5 ml of a 50%/50% mixture of lidocaine 1% and sensorcaine 0.5% will be injected under pressure. The needle will be returned to its original angle deep to the median nerve, and the syringe will be changed to inject 40 mg Depo-Medrol in 1ml of saline.

The subcutaneous soft tissues of the ulnar aspect of the wrist at the level of the carpal tunnel will be infiltrated with 2 ml of lidocaine 1% for local anesthetic. Using ultrasound guidance and aseptic technique, the needle will then be angled deep to the median nerve within the carpal tunnel, and 40 mg Depo-Medrol in 1ml of saline will be injected into the area deep to the median nerve.

The BCTQ is a five-point rating scale with 19 items. The overall score is the average score across all items. The score will be recorded for each visit and change in score will be plotted over time.

Cross-sectional index (CSI) of the median nerve as measured by ultrasound. The CSI will be recorded for each visit and change will be plotted over time.

Motor conduction velocities will be recordedfor each visit and change in these values will be plotted over time.

Sensory conduction velocities will be recordedfor each visit and change in these values will be plotted over time.

The DASH is a 30-item measure using five-point Likert scales assessing aspects of physical functioning and symptoms, intended specifically to measure disability. Its overall score is between 0 and 100. The score will be recorded for each visit and change in score will be plotted over time.

The VAS is a commonly used, subjective scale in which the patient rates their pain on a scale ranging from 0 to 10 (0, no pain; 10, maximum pain possible). The score will be recorded for each visit and change will be plotted over time.

Inclusion Criteria: Adult men or women aged 18 years or greater. Clinical and electromyographic diagnosis of Carpal Tunnel Syndrome. Persistent symptoms from Carpal Tunnel Syndrome after at least three months of appropriate splinting. Ability to consent for study. Exclusion Criteria: Acute symptom onset (less than 3 months). Bifid median nerve Anticoagulation with International Normalized Ratio (INR) > 1.4, or platelets <150. Anomalous muscles (eg. inverted palmaris longus). Patients requiring anti-platelet medication for the treatment of heart attack, stroke, or other medical condition. Previous surgery for Carpal Tunnel Syndrome. Previous local injections, including steroids within the past 6 months. Allergy to any of the injection agents.