The quest for effective pain control during suture adjustment after strabismus surgery: a study evaluating supplementation of 2% lidocaine with 0.4% ropivacaine

PURPOSE: To determine whether the addition of 0.4% ropivacaine to the standard 2% lidocaine peribulbar anesthetic block improves pain scores during suture adjustment in patients undergoing strabismus surgery with adjustable sutures. METHODS: Prospective, double-blind study of 30 adult patients aged 21–84 years scheduled for elective strabismus surgery with adjustable sutures. Patients were divided into two groups of 15 patients each based on the local anesthetic. Group A received 2% lidocaine and Group B received 2% lidocaine/0.4% ropivacaine. Pain was assessed using the visual analog scale (VAS) preoperatively and at 2, 4, and 6 hours postoperatively. The Lancaster red-green test was used to measure ocular motility at the same time points. RESULTS: The pain scores in the two groups were low and similar at all measurement intervals. The VAS for Group A versus Group B at 2 hours (1.7 versus 2.4, P=0.5) and 4 hours (3.5 versus 3.7, P=0.8) showed no benefit from the addition of ropivacaine. At 6 hours, the VAS (3.7 versus 2.7) was not statistically significant, but the 95% confidence interval indicated that ropivacaine may provide some benefit. A repeated measures ANOVA did not find a statistically significant difference in VAS scores over time (P=0.9). In addition, the duration of akinesia was comparable in both groups (P=0.7). CONCLUSION: We conclude that the 50:50 mixture of 2% lidocaine with 0.4% ropivacaine as compared to 2% lidocaine in peribulbar anesthetic blocks in adjustable-suture strabismus surgery does not produce significant improvements in pain control during the postoperative and adjustment phases. In addition, ropivacaine did not impair return of full ocular motility at 6 hours, which is advantageous in adjustable-suture strabismus surgery.