Assessing The Efficacy of Single Inferomedial Peribulbar Injection in Lacrimal Intubation Surgery in Adult Patients: A Randomized Clinical Trial

Abstract

Background: Inferomedial injection has been suggested as a more comfortable alternative to medial peribulbar block. Aim: We aimed to explore inferomedial injection technique efficacy in minimizing pain during injection as well as intubation compared to the classic medial canthal injection technique during peribulbar block. Methods: This randomized, controlled trial included adult (18 to 70 year-old) patients scheduled for lacrimal intubation surgery. Eligible patients were divided in a random way into two groups. Group 1 (n=24) received inferomedial peribulbar injection using a 25G/ 1" length needle to inject 3 ml of lidocaine: bupivacaine (1: 1) with 30 IU hyaluronidase enzyme to improve the infiltration of the small volume of the local anesthetic drugs. The classic medial canthus injection was applied in Group 2 (n=24) using the same types and amounts of local anesthesia (LA) and the same needle length. The pain was assessed during local anesthetics injection and intubation using the verbal rating scale. Results:In group 1 a low pain score was more frequent than in group 2 (83.3% vs. 16.7%). The median pain score at the LA injection was significantly lower in group 1 (1.0: IQR=1.0-1.0) than in group 2 (2.0: IQR=2.0-2.5). Alternatively, a comparison of the Verbal Rating Scale at intubation revealed comparable results between groups 1 and 2, with no significant differences (p>0.05). Conclusions: Inferomedial LA injection technique is feasible and less painful than the medial canthal injection. Otherwise, both techniques provided adequate intraoperative analgesia during lacrimal intubation and comparable surgeon satisfaction.