Tube Shunt Reoperation Rates Equivalent to Trabeculectomy with Mitomycin C

Tube shunt reoperation rates are not significantly different from reoperation rates after trabeculectomy with mitomycin C, according to research published in Ophthalmology Glaucoma. Additionally, for patients who did require additional glaucoma surgery, outcomes were similar regardless of which initial procedure the patient underwent.

Researchers conducted a multicenter, randomized, cohort study to evaluate the incidence and outcomes of reoperations for glaucoma.

The study enrolled 242 patients with medically uncontrolled glaucoma and no previous incisional ocular surgery. The researchers compared outcomes for 125 patients who underwent placement of a 350 mm² Baerveldt glaucoma tube shunt implant (mean age, 60.1±9.9 years; 71% women and 29% men) with 117 who underwent trabeculectomy with 0.4 mg/ml mitomycin C for 2 minutes (mean age, 64.2±13.4 years; 50% women and 50% men). 

The main outcome was additional glaucoma surgery. Patients were scheduled for follow-up visits at 1 day, 1 week, 1 month, 3 months, 6 months, 1 year, 18 months, 2 years, 3 years, 4 years, and 5 years postoperatively.

Additional glaucoma surgery was performed in 21 patients in the tube-shunt group and 12 patients in the trabeculectomy group, the investigators report. The study shows a 5-year cumulative tube shunt reoperation rate of 18.0% and 10.4% in the trabeculectomy group (P =.15). 

“Nearly all patients in the trabeculectomy group who needed additional glaucoma surgery underwent placement of a tube shunt, and a similar observation was made in the TVT Study,” the researchers explain. “In the tube group, implantation of a second tube shunt and cyclophotocoagulation were the most common glaucoma procedures following primary tube shunt failure.”

Limitations of the study included surgeon-choice for trabeculectomy or tube shunt reoperation, the low number of patients requiring additional glaucoma surgery, and no masking of patients and investigators.