Authors: Aditya Bansal, Sumana C. Naidu, Natalia Figueiredo, Mahmoud Alrabiah, Hesham Hamli, David T. Wong, Rajeev H. Muni, Filiberto Altomare.

Author Disclosure Block: A. Bansal: None. S.C. Naidu: None. N. Figueiredo: None. M. Alrabiah: None. H. Hamli: None. D.T. Wong: None. R.H. Muni: None. F. Altomare: None.

Purpose: Anatomical and functional outcomes of a 38-gauge cannula-based subretinal fluid (SRF) drainage technique in pars plana vitrectomy (PPV) for primary rhegmatogenous retinal detachment (RRD). 

Study Design: Retrospective Observational Case Series. Methods: We screened charts from July 2019 to June 2021 of patients with primary RRD (macula on/off) who underwent PPV. Inclusion criteria were defined as age >18 years, 38-gauge cannula-based SRF drainage during PPV, and a minimum of 3 months follow-up postoperatively. No laser retinopexy was performed at the drainage site. Eyes with PVR grade C or more and/or any other underlying ocular pathology were excluded from the study. The anatomical outcome was described as a single surgery success rate at 3 months postoperatively. The functional outcome used was visual acuity in logMAR at the 3 months after surgery. We also assessed OCT-based structural abnormalities at 3 months postoperatively. All data are reported descriptively using medians and interquartile range (IQR). 

Results: Nineteen eyes of nineteen consecutive patients had primary RRD repair using a 38 gauge cannula-based SRF drainage technique. From these 19, only 15 eyes had a minimum of 3 months follow-up. The median age at the time of presentation was 61.8 (IQR 53.7-68.9) years and the median duration of follow-up following surgery was 10 (IQR 5-13.5) months. The median baseline logMAR visual acuity was 1.2 (Snellen equivalent 20/300) (IQR 0.3-2.2). 80% of eyes (12/15) had single surgery success at 3 months after surgery. The median logMAR visual acuity at 3 months postoperatively was 0.2 (Snellen equivalent 20/30) (IQR 0.1-0.7). Out of these 12 single surgery success eyes, none of them had residual SRF or post-operative cystoid macular edema and only one (8.33%) had a significant epiretinal membrane at 3 months following PPV. 

Conclusions: 38-gauge cannula-based SRF drainage is an efficacious technique that can be used as an alternate method of subretinal fluid drainage technique.