Different techniques of transconjunctival cannulated vitrectomy versus conventional non-cannulated vitrectomy in various vitreoretinal disorders

PURPOSE: To evaluate the safety and efficacy of different methods of transconjunctival cannulated vitrectomy versus conventional non-cannulated vitrectomy in various vitreoretinal disorders. METHODS: A prospective randomized study was done from August 2009 to February 2011. The study included 129 eyes of 122 patients, randomly divided into four groups. Group 1 comprised 34 eyes operated on using transconjunctival 20-gauge cannula Claes system. Group 2 comprised 32 eyes operated on using transconjunctival cannulated 23 gauge system. Group 3 comprised 27 eyes operated on using combined 20-gauge non-cannulated and 23-gauge transconjunctival cannulated system. Group 4 comprised 36 eyes operated on using conventional non-cannulated 20-gauge system. RESULTS: The four groups were demographically similar. Anatomical outcome was achieved in all cases. Vision was improved in 29 eyes (85.3%) in group 1, 23 eyes (71.9%) in group 2, 19 eyes (70.4%) in group 3, and 26 eyes (72.2%) in group 4. There was no statistical difference between the four groups 1-day postoperative (P=0.405) and 1-week postoperative intraocular pressure (P=0.254). The number of sutureless sclerotomies was 68 (66.6%) in group 1, 78 (81.3%) in group 2, 50 (61.8%) in group 3, and 0 in group 4. Hypotony occurred in one eye (2.9%) in group 1, three eyes (9.4%) in group 2, two eyes (7.4%) in group 3, and no eyes in group 4. Operative endophthalmitis did not occur in any one of the four groups. CONCLUSION: Final anatomical and functional outcomes were not related to the type of sclerotomy used (cannulated or non-cannulated), the gauge used (20 or 23), the route (transconjunctival or transscleral), or type of suture used. The advantages of small-gauge transconjunctival vitrectomy were patient comfort, early ambulation, and preservation of the conjunctiva. This should be weighed against the cost of this cannula system.