Is Trabectome Effective After Failed Tube-Shunt Surgery?

Shuchi B. Patel, MD


November 18, 2015


Until recently, it was taught that tube shunts are reserved for refractory glaucomas that have failed prior laser or incisional procedures. The results of the Tube versus Trabeculectomy study[1] promoted the insertion of tubes even as the first surgical intervention for the treatment of glaucoma for which medical or surgical therapy failed. The number of patients with tube shunts increased as a result, yet the failure rates of the most commonly used implants ranges from 30% to 50% at 3 years.[2,3,4]

The options after a failed tube-shunt operation are limited owing to excessive conjunctival scarring. Trabectome is a trabecular bypass procedure that does not involve a conjunctival incision and is performed via an ab interno approach through clear cornea. In the traditional algorithm for treatment of glaucoma, this procedure usually falls before filtering surgery but after medical and surgical therapy for the treatment of early to moderate glaucoma.

However, the current study indicates the potential benefit of Trabectome in refractory glaucoma as well. Prior published studies on the Trabectome procedure have reported success rates between 50% and 89%.[5,6,7] In these cases, typical IOP after Trabectome was in the mid-teens, with patients often still requiring IOP-lowering medications to maintain this level of control.

Furthermore, Trabectome was performed before any other surgical intervention for glaucoma. These same success rates cannot necessarily be expected when Trabectome is performed for more severe glaucoma cases, as well as in cases where prior filtering surgery has already been performed, altering aqueous outflow. Thus, the current study was important to establish evidence that Trabectome has some efficacy in these cases.

Given the ease in performing this procedure and its relatively quick learning curve, many ophthalmologists—especially glaucoma specialists—have incorporated Trabectome into their surgical armamentarium. Being able to expand the use of this surgical option beyond just early to moderate glaucoma to even refractory cases is therefore very enticing. In cases where further surgical intervention has significantly high risks or the only remaining option seems to be ciliary body destruction, Trabectome may offer hope. Many physicians would find that the low-risk profile makes this an ideal procedure to offer. Further evidence to support this may expand the utility of Trabectome and offer both patients and physicians more options in clinical care.

The study was limited by its small sample size. Additional studies with a larger sample size and longer follow-up will provide better evidence of the utility of Trabectome in certain cases. Unfortunately, many cases of failed tube shunts occur in patients with neovascular, inflammatory, or closed-angle glaucomas that are not candidates for Trabectome, and thus the search for more options in these indications continues.



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