WALANT Procedure in Carpal Tunnel Release

Median nerve neurolysis at the carpal tunnel is one of the most performed procedures in the world. The use of loco-regional anesthesia (LRA) is common practice for this surgery, especially since the use of ultrasound guidance, which allows visualization of the nerves and control of the injection of anesthetic products, makes it a safe technique. The nerve blocks most commonly used in hand surgery are axillary blocks and truncal blocks. The choice between these two techniques, which are equivalent in terms of effectiveness and duration of anesthesia, depends in practice on the habits of each practitioner. As the use of a pneumatic tourniquet during the operation is systematic, the axillary block, by anaesthetizing the whole arm, avoids the discomfort described by some patients when using a tourniquet. For others, the discomfort is related to the sensation of a "dead arm" with a duration of anesthesia of several hours, which the truncular block makes it possible to avoid.

Recently, an alternative to traditional LRA by local anesthesia without tourniquet and without sedation (WALANT procedure: Wide Awake Local Anesthesia with No Tourniquet) has been described. Several studies show the efficacy and safety of this procedure, which is already used in current practice.

However, to date, there is no comparative study evaluating the effectiveness of the WALANT procedure compared to traditional hand surgery techniques for carpal tunnel, neither published nor in progress. This is the purpose of this study.

The WALANT technique, performed under ultrasound, includes two punctures.

• The first is a puncture through a medial approach above the wrist and includes two injections. A first subcutaneous injection reproducing a bar above the wrist flexion line, and a second injection above the median nerve. The volumes injected vary from 8 to 10 milliliters (ml).
• The second puncture is performed at the base of the palmar surface of the hand and consists of a 10 ml subcutaneous injection of the local anesthetic in order to take advantage of the vasoconstrictive effects of adrenaline, thus allowing the surgical procedure to be performed without a pneumatic tourniquet.

Inclusion criteria

• Male or female patient over 18 years of age
• Membership in a mandatory health insurance plan
• Patient treated for a first median nerve liberation surgery at the carpal tunnel
• Patient having been informed of the study and having given informed consent
• French-speaking patient

Exclusion criteria

• Surgical revision
• Contraindication(s) to loco-regional anesthesia :

• Coagulation disorder or ongoing anticoagulant therapy
• Existing peripheral neuropathy
• Amide-type AL allergy
• Pregnant or breastfeeding women
• Inability to undergo the medical follow-up of the study for geographical, social or psychological reasons
• Patients under legal protection
• Patients under the influence of drugs that may interfere with the anesthetic techniques under study (cocaine, cannabis, etc. as judged by the investigator)
• Inclusion of the subject in another research protocol during this study