Placing the Molteno implant in a long scleral tunnel to prevent postoperative tube exposure

Purpose: The purpose of this study was to retrospectively evaluate whether it is possible to decrease the risk of Molteno tube erosion through the conjunctiva by using a new technique where the silicone tube is inserted into a scleral tunnel instead of being covered only by the conjunctiva. Methods: We reviewed Molteno implants carried out at the University Hospital of Oulu, in 332 patients who underwent traditional Molteno implantation between October 1986 and October 1998 and 92 patients who underwent surgery with the new technique between November 1998 and April 2001. Results: With our former technique, conjunctival erosions occurred in 15 eyes of 15 patients (4.5%) after a median follow-up of 3.5 months (range 1-72 months); no conjunctival complications were discovered in patients who underwent surgery using the new technique during a median follow-up of 22 months (range 10-39 months). (p = 0.038, two-sample test of proportions). Conclusion: Inserting the Molteno tube into a scleral tunnel prevents tube extrusion through the conjunctiva in eyes with Molteno implants. The technique for making the scleral tunnel is described.