EMLA® cream prior to digital nerve block for ingrown nail surgery does not reduce pain at injection of anesthetic solution

Background: Needle penetration and local anesthetic infiltration are painful steps of digital ring block. The objective of this study was to evaluate the efficacy of EMLA® cream application prior to digital ring block for surgery for ingrown big toenail. Methods: We conducted a prospective, double-blinded, placebo-controlled, randomized clinical trial with 81 patients (range: 12-75years, mean±SD: 30.3±17.5years), who underwent big toenail surgery. Prior to the digital block, EMLA cream (Group E) or a placebo cream (Group P) was applied. A visual analog scale (VAS) and a verbal rating score (VRS) from 1 to 10, 10 being most severe pain, were used for assessment of pain during the skin needle penetration and during the infiltration of the anesthetic product. Results: Data of the VAS and of the VRS during the two steps, respectively, show no significant difference in pain rating between the two groups. In Group E, the gender of the patients had a significant effect on pain perception. Male patients reported less pain than female patients, both during the needle skin penetration and during the infiltration step (P<0.005). In Group P, reported pain did not differ by gender in either step of the procedure. Conclusions: We found no clinical benefit in using EMLA during digital nerve block. Although the digital nerves are not deeply located in the small subcutaneous space of the digit, topical anesthesia may not reach them. Moreover, swelling due to injection of the anesthetic product in this small space may also amplify the sensation of pain.