Author: Marko Popovic (Canada)
Co-authors: Yuri Chaban, Anubhav Garg, Rajeev Muni, Peter Kertes
The increasing focus on minimally invasive surgery has driven the development of small gauge (SG; i.e. 23-G, 25-G, 27-G) pars plana vitrectomy (PPV) systems, which have been postulated to offer minimal sclerotomy trauma, self-healing sutureless sclerotomies, improved operative efficiency, and quicker post-operative anatomical and visual recovery. Despite their high interest and near universal uptake, uncertainties in the advantages and disadvantages of different SG PPV systems remain and must be addressed. To provide clarity on the use of different PPV systems for any surgical indication, the present meta-analysis of randomized controlled trials (RCTs) was undertaken.
Meta-analysis of randomized controlled trials (RCTs).
A systematic literature search was performed on Ovid MEDLINE, EMBASE, and Cochrane Central from inception to February 2020. RCTs comparing at least two different PPV systems were included. Risk of bias was assessed using version 2 of Cochrane’s risk of bias assessment tool for RCTs and evidence certainty was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) guidelines. Study outcomes included best corrected visual acuity (BCVA), reattachment rate, surgical time, and the incidence of complications. Weighted mean differences (WMD) and risk ratios (RR) with 95% confidence intervals (CIs) were calculated, and meta-analysis was performed with random effects models for all analyses.
1,286 eyes from 19 RCTs were included. A low-moderate risk of bias was detected across the included studies. Relative to 20-G, SG PPV did not significantly improve BCVA, reattachment rate, or total surgery time. SG PPV was associated with a higher incidence of hypotony (RR, 3.79; 95% CI, 2.02 to 7.10; P<.001) and choroidal detachment (RR, 5.65; 95% CI, 1.01 to 31.71; P=.05). Compared to 25-G PPV, 23-G did not improve BCVA and required more frequent port suturing (RR, 0.46; 95% CI, 0.25 to 0.84; P=.01). 27-G PPV was associated with a longer surgery (WMD, 5.71 minutes; 95% CI, 2.26 to 9.15; P=.001) and improved BCVA 3 months postoperatively (WMD, -0.11 logMAR; 95% CI, -0.21 to -0.01; P=.03) relative to 25-G. The incidence of complications did not significantly differ between 25-G and 23-G or 27-G PPV.
SG PPV does not improve visual acuity, reattachment rate, or total surgical time versus 20-G PPV, and increases the risk of postoperative hypotony and choroidal detachment (GRADE: medium certainty of evidence). Between SG PPV systems, 23-G PPV requires more frequent sclerotomy suturing with no benefits over 25-G (GRADE: low-medium certainty of evidence). 25-G has worse absolute visual acuity compared to 27-G but shortens total surgery time (GRADE: low-medium certainty of evidence).
PJK: Advisory board – Novartis, Alcon, Bayer, Allergan, Novelty Nobility; Financial support (to institution) – Allergan, Bayer, Roche, Novartis; Financial support – Novartis, Bayer, Zeiss; Scientific Advisory Board – Novelty Nobility; Equity owner – ArcticDx. RHM: Advisory board- Bayer, Novartis, Allergan, Roche; Financial Support (to institution)- Bayer, Novartis.