[Comparison between Greenbaum's parabulbar anesthesia and Ripart's subtenon anesthesia in the anterior segment surgery]

Abstract

Purpose: To compare two methods of sub-tenon anesthesia in 80 surgical procedures (phakoemulsification, glaucoma and combined surgery) in a prospective, single-surgeon study.

Materials and methods: Forty patients requiring anterior segment surgery in each eye were randomised to receive subtenon anaesthesia by either Greenbaum's method (using a flexible plastic cannula) or Ripart's method (using a 23G hypodermic needle). Randomization dictated the mode of anaesthesia for the first eye, the other technique being used for the second eye. Anaesthesia consisted of 1.5ml lidocaïne 2% and 1.5ml bupivacaïne 0.5% in all cases, and was performed by the same surgeon (EDLM) immediately before surgery. Type of surgical procedure, duration, complications, presence of sub-conjunctival haemorrhage, were assessed by the surgeon, who also graded chemosis (0-3), nuclear hardness (1-4), and ocular akinesia (0-2) for each patient. Pain was scored subjectively by each patient (0-10) during the injection, peroperatively and postoperatively.

Results: Chemosis was significatively higher with Greenbaum's method than Ripart's method (p<0.01) and was sometimes undesirable for the surgeon. There was no difference in the pain score during the injection, preoperatively or postoperatively. Pain was usually very light and did not correlate with the duration of surgery. There was no akinesia in the majority of cases with either method, but the surgeon was sometimes limited by the akinesia of the medial rectus muscle and often by that of the inferior rectus muscle with elevation of the globe.

Conclusion: Greenbaum's method and Ripart's method are two subtenon anesthesic techniques characterized by an immediate, intense and prolonged analgesia (sometimes 60mn). Complete akinesia is rare and this is sometimes limiting. Chemosis was more often associated with Greenbaum's method, but Ripart's method carries the potential for needle-related complications.