Evaluation of Postoperative Povidone-Iodine in Adjustable Suture Strabismus Surgery to Reduce Suture Colonization: A Randomized Clinical Trial.

Importance: Although the association between suture colonization and postoperative infections remains hypothetical, measures to reduce perioperative suture colonization may minimize postoperative infections. The suture colonization rate in adjustable suture strabismus surgery is not well defined, and the effect of povidone-iodine use on suture colonization is unknown.

Objective: To assess whether povidone-iodine application at the end of adjustable suture strabismus surgery decreases the suture colonization rate.

Design, Setting, and Participants: In this randomized clinical trial designed in 2015 and performed from June 1 through October 31, 2015, a total of 65 adjustable and 43 control suture specimens from 65 demographically similar adults undergoing adjustable suture strabismus surgery were studied. A random sampling assigned participants into group 1 (with povidone-iodine) or group 2 (without povidone-iodine) at the end of surgery. A control suture specimen was obtained if ipsilateral nonadjustable surgery was performed. Both groups received antibiotic ointment at the end of the procedure. No patients refused participation or withdrew. Data analysis was performed from October 1 to December 31, 2015. Observers were unaware of patient grouping.

Interventions: One drop of 5% povidone-iodine directly over the sliding noose of the adjustable suture at the end of surgery.

Main Outcomes and Measures: The suture colonization rate after adjustment in group 1, group 2, and the control group.

Results: Of 65 adults undergoing surgery, there were 17 men (49%) and 18 women (51%) in group 1 and 10 men (33%) and 20 women (67%) in group 2, as well as 20 men (47%) and 23 women (53%) in the control group. The mean (SD) age of the patients was 48.5 (16.8) years in group 1, 46.6 (18.1) years in group 2, and 47.7 (17.0) years in the control group. There was no difference in the colonization rate between group 1 (57%) and group 2 (47%) (relative risk [RR], 1.1; 95% CI, 0.6-1.7; P = .80), group 1 and the control group (44%) (RR, 1.0; 95% CI, 0.5-1.8; P > .99), or group 2 and the control group (RR, 1.3; 95% CI, 0.8-2.1; P = .62). Eleven bacterial species were identified. Staphylococcus epidermidis was the predominant isolate (40 of 56 [71%]). A longer interval between the end of surgery and adjustment was associated with higher culture positivity (6.3 hours in positive vs 4.4 hours in negative cultures, P = .001); however, there was no difference in bacterial growth between the groups. No adverse effects of povidone-iodine were observed.

Conclusions and Relevance: This study was not able to demonstrate that povidone-iodine at the end of adjustable suture strabismus surgery reduces the suture colonization rate.

Trial Registration: clinicaltrials.gov Identifier: NCT02424357.