Trabectome-Initiated Gonioscopy-Assisted Transluminal Trabeculotomy

To introduce a trabectome-initiated gonioscopy-assisted transluminal trabeculotomy (TIGATT) procedure and to report preliminary results.

A preliminary case series of eight patients who have undergone the newly proposed TIGATT procedure is presented. TIGATT is a new concept that modifies established techniques by replacing the initial goniotomy incision of gonioscopy-assisted transluminal trabeculotomy (GATT) with an ab interno trabeculectomy ablation utilizing the trabectome. All surgeries were performed by a single surgeon (W.I.K.) between November 2014 and October 2015 in adults with primary open-angle glaucoma. Recorded outcome measures were intraocular pressure (IOP), number of medications, and complications.

Eight patients with an age range of 63-93 yr underwent TIGATT with at least 3 mo of follow-up. Five of the eight initial patients had follow-up to 2 yr. The mean pre-operative IOP was 25 mmHg (standard deviation [SD] 7.0) on four medications (SD 1.1). The mean post-operative IOP at 3 mo was 14 mmHg (SD 1.8) on two medications (SD 1.3). The average decrease in IOP was 9.9 mmHg (SD 7.5) with an average decrease in medications of two (SD 1.4) at 3 mo. At 2 yr, the mean post-operative IOP was 14 mmHg (SD 3.2) on one medication (SD 1.1). The average decrease in IOP was 7.8 mmHg (SD 3.1) with an average decrease in medications of two (SD 1.8). There were two treatment failures that required further glaucoma surgery and one patient was lost to follow-up.

The preliminary results and safety profile for TIGATT are promising and appear at least comparable with previously published results for both GATT and trabectome. Initiating the transluminal trabeculotomy with trabectome clearly exposes Schlemm's canal and facilitates threading the microcatheter into the canal. Additionally, if the 360-degree trabeculotomy cannot be completed because of an incompletely patent Schlemm's canal, the patient will at least have a trabectome ablation that can serve as their glaucoma surgery.