Purpose: Hemostasis and local anesthetic injection are essential for minor hand surgeries under local anesthesia (LA). Wide awake local anesthesia no tourniquet (WALANT) became popular for achieving hemostasis without a tourniquet. However, a recent study reported that injection is more painful than tourniquet use in minor hand surgery. Therefore, this study aimed to compare three LA methods that differ according to injection and hemostasis, namely, the combination of a tourniquet and buffered lidocaine solution (CTB), WALANT, and conventional LA. Methods: This randomized prospective single-center study included 169 patients who underwent minor hand surgery between 2017 and 2020. We randomly allocated the patients to each group and recorded the pain and anxiety score during the surgery, as well as satisfaction after the surgery. Results: Pure lidocaine injection was significantly more painful than buffered lidocaine and WALANT solution injection ( p < 0.001). Local anesthesia injection was significantly more painful than tourniquet use in all groups ( p < 0.001). The intraoperative anxiety score was significantly lower in the CTB group than in the conventional LA and WALANT groups ( p < 0.001). The satisfaction score was significantly higher in the CTB and WALANT groups than in the conventional LA group ( p < 0.001). Conclusion: CTB for minor hand surgery under LA is associated with less injection pain and patient anxiety. The tourniquet is tolerable without much pain and waiting time. Thus, CTB in minor hand surgery is a good alternative to WALANT and conventional LA.

Background: Ulnar neuropathy is a common reason for referral to hand surgeons, and 10 to 30% of cubital tunnel syndrome (CuTS) is idiopathic. We hypothesized that the cause of idiopathic CuTS is in the bony structure. Methods: We analyzed 79 elbows (39 idiopathic CuTS and 40 without CuTS symptom) using computed tomography and Materialize Mimics software to compare the differences between the two groups. We proposed a new bony cubital tunnel with a new boundary that could play a role in ulnar nerve compression symptom. Results: The mean cubital tunnel volume was 1245.6 mm 3 in all patients, 1180.6 mm 3 in CuTS patients, and 1282.3 mm 3 in the control group. A significant difference (p = 0.015) between two groups was found. Bony cubital tunnel cross-sectional area, cubital tunnel depth, and cubital tunnel angle also showed significant differences. Conclusion: The shape of the bony cubital tunnel is an important cause of CuTS, and the normal variation of the volume and cross-sectional area of the cubital tunnel and cubital tunnel angle could influence the occurrence of idiopathic CuTS.

Author's replyWe greatly appreciate your interest to our study and thank you for your comments. We agree that there are many variables which could affect injection pain. We believe that surgeons should be aware of this factor to minimize patient's pain. Our study was begun from this idea. 1 As your comment, injection solution's temperature and injection speed have impact on pain while giving LA injection. However, we are carefully concern about stability of buffered lidocaine when warming solution.In previous study, buffered lidocaine dropped to 66.1% of initial concentrations after 4 weeks when stored at 25°C. 2 We believe that when warming solution up to body temperature (36.5°C) would accelerate decline of concentration of buffered lidocaine. Therefore, we recommend to warm solution just before injection.The rate of administration of LA are very important factor affecting injection pain. However, we believe that speed of injection is only partial element of injection technique. It is important to consider multiple factor to minimize pain such as needle size, length, injection depth and direction, injection amount, etc. Therefore, we recommend to use "hole-in-one" injection technique which is introduced in our article. 1,3