The Wide-Awake Local Anesthesia No Tourniquet (WALANT) technique has become popular for hand surgery in the past decade. It consists of injecting a local anesthetic and epinephrine into the surgical site. Lidocaine, a short-acting local anesthetic, is used in the classic description. Adding a long-acting local anesthetic, such as bupivacaine, has been suggested for long surgeries.~However, the use of bupivacaine in shorter-duration procedures could combine the advantages of ambulatory surgery without a tourniquet with long-acting analgesia, improving postoperative pain and reducing the consumption of analgesics.~Patients undergoing first-time open carpal tunnel release surgery will be randomized to receive bupivacaine or lidocaine. Randomization will be generated by computer using random block sizes of 2 or 4 with an allocation ratio of 1:1.~Postoperatively, patients will receive standard medical care. It consists of 50 mg of diclofenac to take when they feel pain (with a minimum interval of 8 hours). Patients will be instructed to complete a medication log for pain and analgesic consumption. A blinded investigator will contact them by phone at 24 hours and 48hs. At two weeks, they will be controlled by research staff for complications.~Eighty-two patients will be recruited, 41 per arm, assuming a 20% loss. The sample size was calculated using a 90% power and 5% significance level. The objective was to detect a minimum difference of 2 points on a numeric scale ranging from 0 to 10 with a standard deviation of 2.5 points.
The goal of this clinical trial is to compare the use of bupivacaine and lidocaine as local anesthetics in carpal tunnel release surgery. The main questions it aims to answer are:~Are there any differences in pain after surgery?~Are there any differences in postoperative analgesic consumption?