Short versus long-acting local anaesthetic in open carpal tunnel release: which provides better preemptive analgesia in the first 24 hours?

Open carpal tunnel release is commonly performed under local anaesthesia. No study has compared intra-operative short- versus long-acting local anaesthetics as preemptive analgesics in carpal tunnel surgery. In this single-blinded prospective study, 100 consecutive carpal tunnel releases were performed by a single surgeon at one institution with either lignocaine (n = 50) or ropivacaine (n = 50). Allocation was performed via the method of alternation. Subjects were given a questionnaire to answer the following: (1) time to first incidence of pain, (2) quality of first night's sleep, and (3) mean numerical pain scores in the first 24 hours. The time to the first postoperative pain was significantly shorter in the lignocaine group (5.58 vs. 9.17 hours, p < 0.035). There were no significant difference in the incidence of poor first night's sleep (16% vs. 26%, p = 0.28) or mean pain scores in the first day (3.6 vs. 2.9, p = 0.16). Existing evidence advocates for long-acting intraoperative local anaesthetic because it results in a longer duration of postoperative analgesia, however, our study suggests that it may also result in a poorer first night's sleep.