Local Anesthetic Injection Before Incision Decreases General Anesthesia Requirements in Pediatric Trigger Thumb Release: A Randomized Controlled Trial.

Background: Animal studies have shown evidence of neurotoxicity from inhalational anesthesia, yet clinical studies have been less conclusive. While ongoing studies investigate the clinical significance of anesthesia-associated neurodevelopmental changes in young children, reducing anesthetic exposure in pediatric orthopaedic surgery is prudent. The primary objective of this study is to determine if local anesthetic injection before surgical incision versus after surgical release decreased inhalational anesthetic exposure in children undergoing unilateral trigger thumb release. The secondary objectives were to determine if the timing of local anesthetic injection affected postoperative pain or length of stay.

Methods: This was a single-center randomized controlled trial of pediatric patients (4 y and below) undergoing unilateral trigger thumb release. Subjects were randomized into preincision or postrelease local anesthesia injection groups. The surgeon was aware of the treatment group, while the anesthesiologist was blinded. Patient demographics, operative times, cumulative sevoflurane dose, and postoperative anesthesia care unit recovery characteristics were collected. The χ2, Fisher exact, and Mann-Whitney U tests were conducted.

Results: A total of 24 subjects were enrolled, with 13 randomized to the preincision injection group and 11 to the postprocedure injection group. There was no significant difference in age, sex, operative time, or tourniquet time between groups. There was a significant difference in the cumulative sevoflurane dose between the preincision injection group (23.2 vol%; interquartile range: 21.7 to 27.6) and the postprocedure injection group (28.1 vol%; interquartile range: 27 to 30) (P=0.03), with a 21% reduction in cumulative dose. There were no significant differences in postoperative pain scores, use of rescue pain medications, the incidence of nausea, or time to discharge between groups.

Conclusions: Administering local anesthesia before incision versus at the end of the procedure significantly decreased cumulative sevoflurane dose for unilateral trigger thumb release. The results of this study suggest that local anesthetic injection before the incision is a low risk, easy method to reduce general anesthesia requirements during trigger thumb release and could decrease sevoflurane exposure more substantially in longer procedures and mitigate risks of neurotoxicity. Preincision injection with local anesthetic should be incorporated into routine clinical practice.

Level of evidence: Level I.