Alleviating Pain in Oculoplastic Procedures by Reducing the Rate of Injection of Local Anaesthetic

PURPOSE : To investigate whether the rate of infiltration of local anaesthetic influences the pain or efficacy of local anaesthesia in oculoplastic surgery. METHODS : A prospective observational study on consecutive patients undergoing a variety of oculoplastic procedures under local anaesthesia. An observer recorded the rate of injection of local anaesthetic during each procedure. The same mixture of local anaesthetic and the same needle gauge was used in all cases. Patients were asked to rate the pain of both the injection and the surgery using a visual analog scale (VAS). RESULTS : 77 consecutive patients were observed, 39/77 (50.6%) patients were female and the average age was 63.5 years (range 31-94). A statistically significant correlation was found between the rate of injection and the VAS score from the injection (p<0.0001, r=0.42). There was no significant correlation between the injection rate and the VAS score from the procedure itself (p=0.25, r=0.13). Additionally, a significant correlation was found between the injection VAS score and the procedure VAS score (p=0.0002, r=0.42). CONCLUSION : The slower the rate of injection of local anaesthetic, the less pain was reported by the patient from the injection itself. Indeed the perception of pain from the surgery overall was significantly related to the pain felt during the injection, highlighting the importance of minimising pain during the injection of the local anaesthetic. We conclude that slowing the rate of injection is an effective way of alleviating pain from administration of the anaesthetic.