Wide awake local anesthesia no tourniquet (WALANT) versus ultrasound-guided axillary block in carpal tunnel release: a non-inferiority randomized controlled trial

1. For outpatient endoscopic carpal tunnel release, wide-awake local anesthesia without a tourniquet achieves at least the same anesthetic success as an ultrasound-guided axillary brachial plexus block while better preserving immediate hand function and patient comfort.

Evidence Rating Level: 1 (Excellent)

Study Rundown: This prospective, double-blind, single-center non-inferiority randomized trial compared Wide-Awake Local Anesthesia No Tourniquet (WALANT) with ultrasound-guided axillary block (USGAB) for adult outpatients undergoing endoscopic carpal tunnel release. One hundred thirty patients were randomized to receive either ultrasound-guided lidocaine infiltration at the wrist and carpal tunnel (WALANT) or an axillary brachial plexus block (USGAB), with standardized multimodal postoperative analgesia in both groups. The primary outcome was anesthetic success, defined as completion of surgery without any intraoperative supplementation. WALANT achieved a 100% success rate versus 89% with USGAB, meeting the prespecified non-inferiority margin. Postoperative function and pain were similar, but more WALANT patients could dress independently after surgery (92% vs 58%), and EVAN-LR scores suggested less discomfort, although overall satisfaction was comparable. Surgeons rated the operative field quality as equivalent between groups. The authors conclude that WALANT is a safe, effective alternative to USGAB for endoscopic carpal tunnel release and may improve patient comfort and early hand function. 

Click to read the study in BMJ

Relevant Reading: Wide Awake Local Anesthesia No Tourniquet (WALANT) technique improves the efficiency of distal nerve blocks for carpal tunnel release.

In-Depth [Randomized Controlled Trial]: 

Endoscopic carpal tunnel release (eCTR) is one of the most common ambulatory hand procedures, and regional anesthesia is frequently used to minimize opioid exposure and facilitate same-day discharge. Ultrasound-guided axillary brachial plexus block (USGAB) is well established, with reported success rates of 90–95%, but it produces motor block, often necessitates a tourniquet, and may require sedation. Wide-Awake Local Anesthesia No Tourniquet (WALANT) has emerged as an alternative that uses lidocaine with epinephrine infiltrated at the surgical site, avoiding both tourniquet and brachial plexus blockade. However, its efficacy relative to USGAB for eCTR has not been rigorously evaluated in a randomized trial.

This prospective, double-blind, single-center, non-inferiority randomized controlled trial compared WALANT with USGAB in adults undergoing outpatient eCTR. A total of 130 patients were randomized 1:1; 129 were included in the per-protocol analysis. All patients received ultrasound-guided injections by experienced anesthesiologists. The USGAB group received 30 mL of 1% lidocaine around the radial, ulnar, median, and musculocutaneous nerves at the axilla. The WALANT group received 30 mL of a solution consisting of 1% lidocaine with dilute epinephrine, saline, and bicarbonate infiltrated under ultrasound guidance around the median nerve at the wrist and into the carpal tunnel and planned incision site. In both groups, a forearm tourniquet was applied but inflated only in the USGAB group. Light propofol sedation was permitted for block placement. All patients received standardized postoperative oral analgesia (paracetamol and ibuprofen).

The primary outcome was block success, defined as adequate surgical anesthesia without any intraoperative supplementation (sedatives, analgesics, additional local anesthetic, or conversion to general anesthesia). Secondary outcomes included time from block completion to incision, surgery duration, length of stay, functional autonomy on the ward (eating, dressing, walking), regional anesthesia satisfaction (EVAN-LR questionnaire), postoperative pain scores (0–10 verbal rating scale) on day 0 and day 1, surgeon-rated quality of the surgical field (bleeding), and anesthesia-related adverse events.

In the per-protocol analysis, block success was 100% in the WALANT group versus 89% in the USGAB group; seven USGAB patients required supplemental sedatives or analgesics intraoperatively, while none in the WALANT group required supplementation. The predefined non-inferiority margin was −10%; the observed between-group difference in success rate was 11% (90% CI 4% to 17%) in favour of WALANT, confirming non-inferiority and statistically suggesting possible superiority. Time from block to incision, surgery duration, time to home-readiness, and overall length of stay were similar between groups. Functional outcomes were also comparable except for dressing independently on the ward, which was significantly more frequent with WALANT (92% vs 58%). EVAN-LR total and most domain scores did not differ significantly, but the discomfort subscale favoured WALANT. Pain scores at all time points were low and similar between groups. Surgeons rated the operative field as bloodless or with only minimal bleeding in the vast majority of cases in both groups, with no significant difference. Adverse events were rare, minor, and comparable between techniques; no ischemic complications were observed with epinephrine-containing WALANT.

The authors conclude that, for outpatient eCTR, WALANT provides non-inferior—and possibly superior—anesthetic success compared with USGAB, while preserving hand function (no motor block), improving dressing independence, and reducing tourniquet-related and brachial plexus–block–related discomfort. WALANT can be considered a first-line anesthetic option for eCTR in appropriate patients, although the single-center design, exclusion of highly anxious patients, and limited power to detect rare ischemic events warrant further multicenter studies.

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