A Systematic Review and Meta-analysis of Methods for Reducing Local Anesthetic Injection Pain Among Patients Undergoing Periocular Surgery

PURPOSE: Various factors help minimize pain during the injection of local anesthetic. The majority of current evidence involves nonspecific injection sites. The objective of this review was to provide a comprehensive summary of all existing evidence for methods used to reduce injection pain specifically in the context of periocular procedures. METHODS: A literature search of the MEDLINE, EMBASE, and Scopus databases was conducted to identify all relevant experimental and observational studies from 1946 to 2018. Studies were included of patients undergoing periocular surgery under subcutaneous local anesthesia whereby outcomes were reported following a specific intervention intended to help reduce pain. Risk of bias was assessed using recognized tools. A subgroup meta-analysis was performed to indirectly compare pooled intervention-versus-control differences for various pain reduction interventions. RESULTS: Following the review of 2089 search results, 23 articles representing 1135 patients were included. The methods assessed in the studies included choice of anesthetic agent, buffering, warming, dilution, needle type, administration of an inhalational anesthetic, application of topical anesthetics, iontophoresis, skin cooling with ice, tactile distraction with vibration, and decreasing the rate of injection. CONCLUSIONS: Methods demonstrating best efficacy included solution modification (buffering, dilution, warming), skin cooling with ice, vibration, transconjunctival topical anesthetic before injection, and decreased rate of injection. Further study is warranted for modification of equipment factors, topical anesthetics, and strategies to reduce pain because of anesthetic infiltration.