Suture Contamination Rate in Adjustable Suture Strabismus Surgery

To establish the culture positivity rate in adjustable suture strabismus surgery To identify bacterial species and antibiotic susceptibility patterns of microorganisms cultured from suture material To compare suture contamination rates with techniques to reduce the suture contamination rate

Patients will be randomized into 1 of 2 groups: those who received 1 drop of 5% povidone-iodine instilled directly over the sliding noose at surgery completion (group 1) and those who did not receive povidone-iodine at the end of the surgery (group 2). Institutional standard surgical preparation will be performed in all patients with 5% povidone-iodine solution on the periocular skin and eyelid margins, followed by instillation of 1 drop of 5% povidone-iodine into the conjunctival cul-de-sac. All operations will be performed using a sliding noose technique with a polyglactin 6-0 suture (Vicryl, Ethicon Inc). If a patient undergoes surgery on more than 1 muscle in the same eye, a 1-cm section of suture proximal to the knot will be collected from the nonadjustable suture as a control. The control suture will be placed in a tube with 2 mL of trypticase soy broth and agitated for 1 minute. At the end of surgery, patients in group 1 will receive a drop of povidone-iodine. A strip of neomycin sulfate, polymyxin B sulfate, and dexamethasone ophthalmic ointment will be then applied into the lower conjunctival fornix to patients in both groups.

The surgeon will be unaware of the randomization until the end of the surgery. All microbiology personnel and patients will be unaware of the interventional group

patient received 1 drop of 5% povidone-iodine instilled over the adjustable suture noose in addition to routine antibiotic/steroid ointment to operated eye at surgery completion

1 cm section of the suture proximal to the knot will be harvested and placed in a tube with 2 ml of trypticase soy broth (TSB).The TSB tubes will be monitored for growth of bacteria at 48 hours

Comparison of suture colonization rates with and without instillation of a drop of povidone-iodine at surgery completion

The collected sutures will be monitored for bacterial growth for up to 7 days. When bacterial growth is observed, 1 mL of the solution will be inoculated on chocolate, MacConkey, and anaerobic blood agars and incubated for an additional 24 to 48 hours to identify organisms and quantify growth. In vitro susceptibility patterns will be determined.

Inclusion Criteria: All strabismus patients age ≥ 18 years scheduled for strabismus surgery with adjustable sutures at the Bascom Palmer Eye Institute will be invited to participate. Exclusion Criteria: Patient who has a history of allergy to povidone-iodine. Disorders affecting immune function. Patient who is unwilling to participate in the study

Eustis HS, Rhodes A. Suture contamination in strabismus surgery. J Pediatr Ophthalmol Strabismus. 2012 Jul-Aug;49(4):206-9. doi: 10.3928/01913913-20110920-01.

Olitsky SE, Vilardo M, Awner S, Reynolds JD. Needle sterility during strabismus surgery. J AAPOS. 1998 Jun;2(3):151-2. doi: 10.1016/s1091-8531(98)90006-4.

Carothers TS, Coats DK, McCreery KM, Rossman SN, Wilson P, Wu TG, Paysse EA. Quantification of incidental needle and suture contamination during strabismus surgery. Binocul Vis Strabismus Q. 2003;18(2):75-9.

Apt L, Isenberg SJ, Yoshimori R, Chang A, Lam GC, Wachler B, Neumann D. The effect of povidone-iodine solution applied at the conclusion of ophthalmic surgery. Am J Ophthalmol. 1995 Jun;119(6):701-5. doi: 10.1016/s0002-9394(14)72773-4.

Rossetto JD, Suwannaraj S, Cavuoto KM, Spierer O, Miller D, McKeown CA, Capo H. Evaluation of Postoperative Povidone-Iodine in Adjustable Suture Strabismus Surgery to Reduce Suture Colonization: A Randomized Clinical Trial. JAMA Ophthalmol. 2016 Oct 1;134(10):1151-1155. doi: 10.1001/jamaophthalmol.2016.2926.