Subtenon Bupivacaine Injection for Postoperative Pain Relief following Pediatric Strabismus Surgery: a Randomized Controlled Double Blind Trial.

BACKGROUND Strabismus surgery in children is often associated with undesirable intraoperative and postoperative side effects including pain, postoperative nausea and vomiting (PONV), and occulocardiac reflex (OCR). Systemic analgesics have side effects and are contraindicated in some cases. We hypothesized that the preoperative subtenon injection of bupivacaine would reduce postoperative pain and the incidence of side effects adverse effects. METHODS Sixty children (2 to 6 years of age, ASA status I to II) were randomized to receive either subtenon bupivacaine 0.5% or a saline injection before the beginning of surgery in a double-blind manner. Pain scores using the Face, Legs, Cry, Activity, and Consolability (FLACC) scale, incidence of OCR and PONV, requirement of additional systemic analgesia, and time to discharge from the recovery room were compared. RESULTS The pain scores were significantly lower in the subtenon bupivacaine group at 0 min (p = 0.0056) and at 30 min (p = 0.013). There was no significant difference between the two groups at the other time intervals. There was a significant reduction in the incidence of occulocardiac reflex and the incidence of vomiting in the subtenon bupivacaine group. Eight of the 27 patients in the subtenon bupivacaine group required additional systemic analgesia compared to 19 of 29 controls. The time to discharge from recovery room was lower in the subtenon bupivacaine group. CONCLUSION These data provide some evidence that a preoperative subtenon block with bupivacaine combined with general anesthesia allows efficient control of postoperative pain as well as a reduction in the incidence of OCR and PONV in young children undergoing strabismus surgery.