Endophthalmitis after pars plana vitrectomy a 20- and 25-gauge comparison.

Objective: Recent retrospective analyses have suggested that postoperative endophthalmitis may be more frequent with 25- than 20-gauge pars plana vitrectomy (PPV). Because the infection risk may depend on the suturing status of the sclerotomy, and the perioperative anti-infection protocol, we compared the incidence rate of endophthalmitis after sutureless 25-gauge versus sutured 20-gauge PPV on a large cohort of patients operated with a standardized perioperative anti-infection protocol.

Design: Retrospective comparative case series.

Participants: Consecutive patients who underwent 20- or 25-gauge PPVs at a single center over a multi-year period.

Methods: We analyzed 3597 consecutive PPVs. Patients with a pre-PPV diagnosis of endophthalmitis, PPVs performed for implantation of drug delivery devices, or 25-gauge PPVs with all sclerotomies sutured closed were excluded. Patients with > or =1 week of follow-up were divided into 2 study groups by sclerotomy status at the end of surgery: the 20-gauge group had 3 sutured 20-gauge sclerotomies, and the 25-gauge group had > or =1 unsutured 25-gauge sclerotomy. Endophthalmitis was defined by clinical criteria independent of microbiological results.

Main Outcome Measures: The incidence of endophthalmitis was compared between 25- versus 20-gauge groups.

Results: Of 3372 PPV surgeries meeting inclusion and exclusion criteria, 1948 and 1424 surgeries were 20- and 25-gauge PPVs, respectively. Average age (+/- standard deviation) of patients was 54.6 (+/- 22.6) and 64.4 (+/- 16.5) years in the 20- and 25-gauge PPV groups, respectively (P<0.0001). Median post-PPV follow-up time was not significantly different between the 2 groups (12.5 vs 13.0 months; P = 0.69). Endophthalmitis was observed in 1 patient (0.07%; 95% confidence interval, 0%-0.21%) from the 25-gauge group and none in the 20-gauge group (P = 0.42; Fisher exact test, 2-tailed). The use of air/gas endotamponade (P<0.0001) and intravitreal triamcinolone (P<0.001) was more common in 25- versus 20-gauge PPV.

Conclusions: The incidence of endophthalmitis was low in both groups. We were unable to show a significant difference in the incidence of endophthalmitis between sutureless 25-gauge and sutured 20-gauge PPV, and conclude that a careful perioperative anti-infection protocol may reduce 25-gauge PPV endophthalmitis risk to that of 20-gauge PPV.