Comparison of the surgical outcomes of ab interno trabeculotomy using Tanito microhook, suture, and Trabectome

Abstract

Purpose : This study compared the clinical outcomes between ab interno trabeculotomy using Tanito microhook (TMH), suture (sLOT), and Trabectome (TOM) and explored the most beneficial trabecular meshwork (TM) incision range.

Methods : A retrospective analysis of pre- and postoperative (up to 60 months) intraocular pressure (IOP), glaucoma medications, and complications was performed for patients with primary open angle glaucoma who underwent cataract extraction combined with ab interno trabeculotomy using TMH, sLOT, or TOM at Kyoto University Hospital between January 2016 and June 2021.

Results : The mean preoperative IOP was 18.8±4.4, 18.8±6.7 and 17.1±6.1 mmHg in TMH (58 eyes), sLOT (69 eyes), and TOM (29 eyes) groups, respectively (P=0.37). The mean IOP value and IOP reduction% were similar at all the study time points. The mean IOP was 13.6±2.3, 14.1±3.5, and 12.9±2.8 mmHg (P=0.19), and IOP reduction% was 24.7±18.6, 18.8±23.8, and 21.0±18.0 % (P=0.31) in TMH, sLOT, and TOM groups at postoperative 3-moth follow-up. IOP spike and hyphema occurred most often in the sLOT group (27.5%, 26.1%), followed by the TOM group (13.8%, 17.2%), and the least in TMH group (6.9%, 6.9%). In all three groups, patients with spike or hyphema did not undergo wider degrees of incision but achieved similar IOP reduction when compared with those without spike or hyphema. The use of anticoagulant and antiplatelet did not increase the risk of hyphema in each group. A correlation between TM incision degrees and IOP reduction was only found in the TMH group (P=0.0014) and not in the sLOT (P=0.31) and TOM (P=0.41) groups. After mixing all the data and reclassifying them by incision degrees into 1- to 4-quadrant groups, we found that the 2-quadrant group had the least incidence of hyphema (P=0.26) and spike (P=0.02), while the 3-quadrant group had the greatest IOP reduction% (P=0.02). Consistently, TM incision degree was a predicator of postoperative IOP reduction% in multiple linear regression analysis of patients within 270 degrees’ incision (P=0.0002).

Conclusions : TMH, sLOT, and TOM trabeculotomy provided comparable IOP reduction efficacies, while hyphema and IOP spike were more frequent in the sLOT group. Hyphema and IOP spike did not result from wider TM incision degrees. Incision of 90–180° had the least incidence of complications, while a 180–270° incision conferred the greatest IOP reduction.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.