Shunt revision versus additional tube shunt implantation after failed tubeshunt surgery in refractory glaucoma

PURPOSE: To compare tube shunt revision with additional tube shunt after fa iled tube shunt surgery. METHODS: We identified 281 patients who underwent a primary: tube shunt pro cedure from 1985 to 1998 at Indiana University and reviewed 33 eyes of 33 p atients that had failed and required further surgery. Shunt revision was pe rformed in 12, whereas an additional shunt was placed in 21 eyes. Intraocul ar pressure, antiglaucoma medications, visual acuity, and complications wer e noted. Success was defined as at least a 25% reduction in intraocular pre ssure that was deemed clinically adequate. Qualified success was defined as a 25% intraocular pressure reduction but with additional medications or a significant reduction in medications with stable intraocular pressure for p reoperative intraocular pressure less than 21 mm Hg. RESULTS: Preoperative intraocular pressures (mean +/- 95% confidence interv al) for the revision and additional tube groups were 28.8 +/- 5.8 mm Hg and 29.8 +/- 2.7 mm Hg (P = .73), with an average follow-up period of 25.2 mon ths (range, 3 to 108 months) and 34.8 months (range, 6 to 84 months), respe ctively. Final mean intraocular pressure was 25.3 +/- 6.7 mm Hg for the rev ision group and 17.7 +/- 3.4 mm Hg for the additional tube group (P = .037) . Forty-two percent in the revision group versus 62% in the additional tube group achieved at least a qualified success (P = .30, Fisher exact test). Corneal edema was a common complication, especially in the additional tube group. Limitations of this study include the small sample sizes and the une ven distribution of neovascular glaucoma between the two groups (six of 12 in the revision group vs two of 21 in the additional tube group; P = .015, Fisher exact test). CONCLUSIONS: Our series showed that after failed tube shunt surgery, an add itional tube shunt offers better intraocular pressure control than revision by excision of an encapsulated bleb. (Am J Ophthalmol 2000;129:455-460, (C ) 2000 by Elsevier Science Inc, All rights reserved.).