Combined Glaucoma Surgeries Have Greater Success Than Trabeculectomy Alone

Adding limited deep sclerectomy (LDS) to trabeculectomy resulted in lower mean intraocular pressure (IOP) and higher success rates at 12 months when compared with trabeculectomy alone in patients with moderate to advanced primary open-angle glaucoma (POAG) or primary angle-closure glaucoma (PACG) with pseudophakia, according to a study in the Journal of Glaucoma.

The parallel-arm, single-masked, randomized-controlled trial was designed to evaluate the efficacy of LDS in enhancing IOP-lowering outcomes of conventional trabeculectomy, with a focus on pseudophakic eyes. It included 68 patients (68 eyes) with moderate to advanced POAG or PACG with pseudophakia. They were recruited at a tertiary eye care center in Northern India and randomized patients into 2 groups: 35 eyes in group 1 underwent trabeculectomy alone, and 33 eyes in group 2 had trabeculectomy with LDS. Low-dose subconjunctival mitomycin-C (0.1mg/mL for 1 min) was used in both groups.

Primary outcome measure was IOP, and success rates were calculated for patients with IOPs less than or equal to 18, 15, and 12 mm Hg, and at least 5 mm Hg. Secondary outcome measures included evaluation of bleb morphology, presence of an intrascleral aqueous lake, and supraciliary flow on ultrasound biomicroscopy.

Researchers found that mean postoperative IOP at 12 months was 13.4±1.83 mm Hg in group 1 and 12.5±1.67 mm Hg in group 2 (P =.04). For IOP cutoff of at least 15 mm Hg, absolute success was noted in 11 (31.4%) and 22 eyes (66.6%) in groups 1 and 2, respectively (P =.004). The intrascleral lake was detected in 2 (6%) eyes in group 1 and in 9 (29%) eyes in group 2 (P =.02) at 12 months. In 2 eyes (6.2%) in group 2 (and none in group 1 at 12 months), supraciliary flow was detected (P =.02). Trabeculectomy with LDS was associated with a lower rate of failure (hazard ratio: 0.32, 95% CI: 0.13-0.75, P =.009) in the Cox proportional hazard model.

“The results of this randomized-controlled trial suggest a higher likelihood of achieving target IOP with trabeculectomy enhanced with LDS compared to trabeculectomy alone, particularly in pseudophakic PACG eyes,” researchers report. “The current technique is a step towards augmenting the IOP-lowering capability of trabeculectomy and reduce the chances of failure without adding any extra expense to the procedure.”

“In addition, the use of low-dose MMC as done in the present study can reduce the risk of associated long-term complications (especially bleb-related infections and hypotony). Long-term follow-up studies could focus on evaluating and comparing these 2 procedures with additional imaging modalities such as aqueous angiography,” according to the researchers.

The study did have limitations, including that analysis of the intrascleral lake could not be done as a scale variable because it disappeared in subsequent follow-ups. And, while they tried to minimize detection bias by blinding the investigator to IOP, they could not blind for the intervention because the deep scleral pocket is frequently visible on UBM. Plus, follow-up was only 1 year. Another limitation was that the study was performed by a single-surgeon as a single-center intervention trial, so results should not be generalized. They recommend more studies with different surgeons and patients of varied ethnicities to establish the efficacy and safety of this technique and a larger sample size to evaluate the differences in subgroups of POAG and PACG patients.

Reference

Dada T, Sharma A, Midha N, Angmo D, Gupta S, Sihota R. Efficacy of trabeculectomy combined with limited deep sclerectomy versus trabeculectomy alone: a randomized-controlled trial. J Glaucoma. 2021;30(12):1065-1073. doi:10.1097/IJG.0000000000001896