Efficacy of an Electronic Constant-Speed Injector in Reducing Pain of Local Anesthesia in a Scalp Procedure.

[BACKGROUND] Local anesthesia-related pain is associated with injection speed. An electronic constant-speed injector was developed to deliver slow and steady injections, aiming to alleviate pain during dermatologic anesthesia. We aimed to validate the efficacy of an electronic constant-speed injector in reducing pain during local anesthetic infiltration by comparing it with the conventional manual injection method.

[METHODS] Patients undergoing local anesthetic infiltration in an area greater than 5 cm during a scalp procedure were included. Each side of the surgical field was randomly assigned to receive a local injection using either a manual or electronic injector. Patients rated the pain of each injection using the numeric rating scale (NRS).

[RESULTS] A total of 128 patients were enrolled, with a mean age of 45.96 ± 12.19 years. The procedures included scalp micropigmentation and hair transplantation, with most injections located on the frontal scalp. The manual injection had a mean NRS score of 4.30 ± 1.46, whereas the electronic injectors had a score of 2.63 ± 1.04. The mean difference in NRS scores between the 2 methods was 1.68 ± 1.00, indicating significantly lower pain scores with the electronic injector.

[CONCLUSIONS] The electronic constant-speed injector effectively reduced pain associated with local anesthetic infiltration compared with the manual injection method.