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.