Deep sclerectomy and trabeculectomy augmented with Mitomycin C: 2-year post-operative outcomes

Abstract

Purpose: Two-year post-operative outcomes of both deep sclerectomy (DS) and trabeculectomy surgery (Trab) augmented with Mitomycin C (MMC) at a single tertiary eye centre.

Methods: Retrospective review of DS + MMC and trabeculectomy + MMC at a single centre between February 2015 and March 2018. Patients with a minimum of 12-month follow-up were included. Post-operative follow-up: day 1, week 1, months 1/3/6/12/18/24. Primary outcomes: changes in intraocular pressure (IOP) and changes in LogMAR visual acuity (BCVA) pre- and post-procedure.

Secondary outcomes: changes in number of eye drops, number of follow-up clinic visits, post-operative complications and further surgical interventions. Complete success: IOP ≤ 21 mmHg off all IOP-lowering medications. Qualified success: IOP ≤ 21 mmHg on medication. Failure: IOP > 21 mmHg at 24 months or ≤ 5 mmHg on 2 consecutive follow-up visits after 3 months +/- additional incisional glaucoma surgery +/- loss of light perception. Statistical analysis performed using Microsoft Excel + SPSS.

Results: 90 eyes: DS + MMC = 46 eyes, Trab + MMC = 44 eyes. DS + MMC v Trab + MMC: mean pre-op IOP = 19.57 mmHg v 18.89 mmHg, significantly reduced at all post-operative time-points for both groups (p < 0.001). Mean IOP reduction from baseline = 33.94% v 38.39%; > 30% IOP reduction = 54.35% v 68.18%. IOP ≤ 16 mmHg = 82.61% (38/46) v 95.46% (42/44), IOP ≤ 12 mmHg = 52.17% (24/46) v 72.72% (32/44). Complete success = 67.39% v 61.36%, qualified success = 26.09% v 29.55%, failure = 6.52% v 9.09%. Post-op BCVA: no statistically significant differences between two groups (p = 0.09). Mean pre-op drops v post-op drops = 2.98 v 0.38 (DS + MMC; p < 0.001); 2.68 v 0.39 (Trab + MMC; p < 0.001). Further surgical intervention = 13% v 29.55%. Mean number of post-op clinic visits DS + MMC v Trab + MMC = 10.09 v 13.02 (p = 0.005).

Conclusion: Both procedures achieve sustained intraocular pressure and drop reduction at 2 years post-op. DS + MMC has lower complication rates requiring less intervention and significantly fewer clinic visits, which may be an important factor for deciding surgical management of glaucoma patients in the era of Covid-19 to reduce patient/clinician exposure to the virus.

Keywords: Deep sclerectomy; Glaucoma; Mitomycin C; Trabeculectomy.