Combined eVect of Interceed and 5-fluorouracil on delayed adjustable strabismus surgery

Aims/background—To discover a more reliable method of performing delayed suture adjustment as a basis to investigate whether delayed adjustment actually provides more stable results. In order to prevent the formation of postoperative adhesions and delay the time of adjustment, an animal study was performed to determine the combined eVect of physical barriers, Viscoat and Interceed, and a pharmacological agent, 5-fluorouracil (5FU). Methods—38 rabbit eyes were divided into three groups. After recession of the superior rectus muscle (SRM), 5-FU was applied beneath and over the SRM in group 5-FU. Group I-f had Interceed and 5-FU and group I-fv, Interceed, 5-FU, and Viscoat. Delayed adjustment was performed once on each SRM at 1, 2, and 3 weeks postoperatively. The possible length and the necessary force to adjust as well as the degree of adhesions were recorded. Results—5-FU delayed the adjustment for up to 1 week after surgery in three out of four eyes. Combined use of Interceed and 5-FU could delay the adjustment for up to 1 week after surgery in three out of five eyes. Addition of Viscoat could delay the adjustment for up to 1 week after surgery in four out of five eyes. Adjustment was possible on only one of four eyes thereafter. Conclusions—Combined use of Interceed, 5-FU, and Viscoat could delay the adjustment in rabbits until 1 week postoperatively. (Br J Ophthalmol 1999;83:788–791) Adjustable strabismus surgery is an eVective method of providing the surgeon with one more chance to modify the amount of surgical correction in the immediate postoperative period. 2 However, postoperative alignment may drift with time even after placing the eyes in a suitable position with adjustment. Thus, delayed adjustment may be desirable for better postoperative results, 7 but the postoperative healing process causes adhesions, which inhibit such delayed adjustment. Delayed adjustments have been attempted by the implantation of silicone, viscoelastic material, Interceed, polyglactin 910 mesh, or polytetrafluoroethylene (PTFE). In animal experiments, silicone delayed the adjustment up to 8 weeks, viscoelastic material and Interceed up to 1 week, 10 and PTFE up to 4 weeks. However, the silicone can cause discomfort because of its thickness and rigidity and may trigger infection, extrusion, or granuloma formation. As a barrier, Interceed (TC7) is a fabric composed of oxidised, regenerated cellulose specifically designed as a surgical adjuvant to reduce the formation of postsurgical adhesions. It is known to be eVective in reducing postoperative adhesions. Viscoat is a viscoelastic solution composed of sodium hyaluronate and sodium chondroitin sulphate, and has been reported to be eVective for preventing postoperative adhesion formation. 15–18 5-Fluorouracil (5FU) is a fluorinated pyrimidine analogue that inhibits fibroblast proliferation by competitive inhibition of thymidylate synthetase. It is an antimetabolitic agent with cell cycle specificity, thus relatively less toxic than other antimetabolites. It has been used as an antifibrotic agent in glaucoma surgery. This study was designed to assess the eYcacy of Interceed, Viscoat, and 5-FU in delaying adhesion formation and adjustment. Materials and methods Nineteen New Zealand white rabbits, weighing 2.0–3.0 kg, underwent 5 mm recession of the superior rectus muscle (SRM) using double armed 6-0 polyglactin 910 (Alcon Surgical Inc, Fort Worth, TX, USA) in rabbit eyes with future adjustment at postoperative 1 week and double armed 5-0 Dacron (Alcon Surgical Inc, Fort Worth, TX, USA) adjustable suspension sutures in others. General anaesthesia was achieved intramuscularly with 30–45 mg/kg of ketamine hydrochloride and 5–10 mg/kg of xylazine hydrochloride and topical anaesthesia with proxymetacaine (proparacaine) hydrochloride. As a physical barrier, Interceed (TC7, Johnson & Johnson Medical Inc, Arlington, TX, USA) was used in group I-f, and Interceed and Viscoat (Alcon, Fort Worth, TX, USA) in group I-fv. As a pharmacological agent, 5-FU (250 mg/5 ml, Choongwae, Hwasung, Korea) was used in all groups.