The Resection of Extraocular Muscle without Scleral Suture in the Rabbit

PURPOSE: The purpose of this study was to find stability and histological change after resection of extraocular muscle by suturing the proximal and distal muscle segments end to end for elimination of the risk of scleral perforation in the rabbit. METHODS: After dividing rabbits into two groups, we performed the resection of superior rectus muscle. The control group (18 eyes) was treated with conventional operation method in which we placed sutures directly into sclera after resection of muscle, whereas in the experimental group (18 eyes) sutures were placed between proximal and distal muscle segments end to end, without scleral suture, after resection of muscle 3 mm behind the original insertion. We measured the maximum adhesion power at 1day, 1-, 4-, and 8-week postoperative intervals and observed the histopathologic findings at 4- and 8-week postoperative intervals in both groups. RESULTS: In both groups, the maximal adhesion power increased gradually with time at muscle-to-sclera and muscle-to-muscle adhesion site and reached its highest at 8th week. According to histopathologic findings, chronic inflammatory reaction and foreign body reaction were more severe in the experimental group at 4th week, but disappeared at 8th week in both groups. Fibrosis was slightly more severe in the experimental group. CONCLUSIONS: In resection of extraocular muscle for correction of strabismus, muscle-to-muscle suture is thought to be stable and effective way to avoid scleral perforation for the patient whose sclera is thin or abnormal.

The Usefulness of Sutureless Strabismus Surgery with Tissue Adhesives in Rabbit

Inadvertent perforation of the globe is the most severe complication of strabismus surgery using 6-0 vicryl. Previous studies have reported that the incidence of this complication occurs in 1% to 12.1%. In animal experiments using adhesives(Tisseel, Beriplast-P), the tissue adhesives were considered to be good materials for replacement of sutures in strabismus surgery. In clinical application, the bond strength of the immediate postoperative period is the most important factor for the success of the operation. Therefore we performed sutureless strabismus surgery with Tisseel and Beriplast-P in 10 albino rabbits to evaluate the bond strength of the immediate postoperative period. Superior and inferior rectus muscles were ercessed in 2mm length. In 5 rabbits, Tisseel was used, and those rabbits were divided into 5 groups according to the postoperative period : 10 min, 30 min, 60 min, 1 day, and 1 week after operation. The eyes were enucleated to examine the tensile strength. In the other group of 5 rabbits, Beriplast-P was used and the same experiment was performed. The mean adhesion powers in the Tisseel group were 13.13, 20.24, 22.20, 51.25, and 188.76g. gravity at 10, 30, 60 min, 1 day, and 1 week, respectively. In the Beriplast-P group they were 18.28, 22.07, 36.46, 40.73, and 181.14g. gravity. The use of tissue adhesives for sutureless strabismus surgery is considered to be impractical due to inadequate bond strength of the immediate postoperative period. Tissue adhesives with strong tensile strength in the early postoperative period could be useful in strabismus surgery.

Sutureless Strabismus Surgery with Tissue Adhesive in Rabbit Models

Inadvertent perforation of the globe, granuloma and hypersensitivity reaction were recognized complications of the strabismus surgery. We performed sutureless surgery with Beriplast in rabbit model to determine whether this technique can replace the classic suture technique and decrease it's complications. The authors measured maximum adhesion power and observed histopathologic findings at 1st, 2nd, 4th and 8th week following recession of the rectus muscle with Beriplast. Maximum adhesoin power were increased with time such as 210, 300, 480 and 650gm at each week. Pathologically inflammatory and foreign body reactions were decreased with time, and collagen fibers were proliferated at muscle scleral contact area.

Adhesion Power and Histopathologic Findings After Muscle-scleral Tuck of Extraocular Muscles with Absorbable Suture Material in Rabbits

It was reported that muscle-scleral tuck with nonabsorbable suture material helps to preserve anterior ciliary artery circulation and to prevEnt anterior segment ischemia. The authors measured maximum adhesion power and obsesved histopathologic findings at 1st, 2nd, 4th, and 8th week following a muscle-scleral tuck procedure with absorbable suture material in rabbits. Maximum adhesion powers were increasing with time, 110, 120, 150, and 250gm at each week respectively, and kept enough tension for using absorbable suture material Histopathologic findings demonstrated that inflammatory and foreign body reactions decreased with time, and collagen fibers were proliferated at muscle scleral contact area, and fibers in muscle and sclera connected each other and formed firm adhesion. We concluded that muscle-scleral tuck with absorbable suture material maintained adhesion power enough as a rectus muscle strengthening procedure.