Tensile strength of insertional suture techniques in strabismus surgery.

Background: The "lost" extraocular muscle is a serious adverse outcome of seemingly uncomplicated strabismus surgery. One potential cause of this complication is suture slippage in the operated muscle or tendon. The purpose of this study was to determine the relative tensile strengths of three suture techniques commonly used in strabismus surgery and to compare the incidence of suture slippage in the tendon or muscle among these techniques.

Methods: The horizontal rectus muscles of 18 adults pigs were assigned to undergo either recession or resection and were randomized to one of three suture techniques studies. Tension applied to the free ends of the suture was incrementally increased until failure occurred. The two techniques were compared in terms of the mean applied tensions at the time of failure and the incidence of slippage.

Results: No statistically significant difference in mean tension at failure between the three techniques used in recessed or resected muscles was found. Suture slippage in the tendon or muscle occurred in 25% of the trials and was almost evenly distributed among the techniques. Mean tension at slippage did not differ significantly between the techniques. No failure of any kind occurred at less than 100 g applied tension.

Conclusion: Each suture technique appeared to adequately secure to tendon or muscle for recession and resection procedures. Changing techniques is unlikely to alter the incidence of lost muscles in strabismus surgery.