Epinephrine and sodium bicarbonate (NaHCO3) used in wide-awake local anesthesia no tourniquet (WALANT) affect many areas such as hemostasis, injection pain, anesthetic effect and others. However, few clinical trials have focused on injection pain and the duration of anesthetic effect, and no prospective studies have reported the benefits of WALANT post operation. This study compared WALANT with conventional local anesthesia with tourniquet in minor hand surgeries, and aimed to answer following questions: (1) Does WALANT have enough benefits for injection pain and duration of anesthetic effect? (2) How does WALANT affect postoperative management (such as postoperative pain and use of analgesics)? (3) How satisfied are the patients with the surgery?

We hypothesized that WALANT had advantages in injection pain, duration of anesthetic effect, and postoperative management compared to conventional local anesthesia.

The present study is designed as a randomized prospective one center study. This study included 185 patients who received surgical treatment for the diagnosis of carpal tunnel syndrome, trigger finger, or de Quervain's disease between 2017 and 2019. We randomly allocated the patients to either the WALANT group or the conventional group. We inquired and recorded patients’ injection pain, duration of anesthetic effect, postoperative pain, the use of analgesics, and satisfaction with the surgery.

The injection pain was significantly lower in the WALANT group in all procedures (p<0.001). The duration of anesthetic effect was significantly longer in the WALANT group in all procedures (p<0.001). As for the postoperative management of all procedures, the pain score was significantly lower in the WALANT group until the first day after surgery, with the biggest difference at 6hours after surgery. The use of analgesics was significantly lower in the WALANT group until the second day after surgery. Satisfaction with surgery was significantly higher in the WALANT group in all procedures: A1 pulley release (p=0.026), 1st extensor retinaculum (p=0.045), and carpal tunnel release (p=0.003).

Our study showed better results in WALANT than in the conventional method, with no tourniquet pain, lower injection pains, longer anesthetic duration, and less postoperative pain. It provided patients with great satisfaction. In addition, WALANT has the potential benefits of no time limit due to tourniquet pain and long anesthetic effect. Therefore, WALANT is comfortable and cost effective, and could be a good alternative to conventional local lidocaine anesthesia.

II.