Mechanical Property Comparison of 23, 25 and 27 Gauge Valved Trocars Across 3 Different Systems

Abstract

Purpose : The development of valved trocars in vitreoretinal surgery has mitigated concerns that previously existed with non-valved trocars such as globe collapse and vitreous incarceration. However, repeated instrument insertion and removal may occasionally damage valved trocars. Specifically, during air fluid exchange, trocar leakage may create air bubbles on the corneal surface, inhibiting adequate visualization and making necessary maneuvers more challenging. Therefore, the purpose of the current study was to compare the integrity of valved trocars across a range of surgical brands and gauge sizes, analyzing their mechanical properties.

Methods : This study evaluated 72 valved trocars (24 each from Alcon, DORC, and B/L, evenly split across 23, 25 and 27 gauge sizes) for their competence under simulated retina surgery infusion pressures (40 mmHg, 60 mmHg) through a custom setup. Trocar valve competence was assessed through performing repeated instrument exchanges until two separate previously identified failure endpoints were reached. The number of instrument exchanges required prior to failure was then recorded. Analysis was performed via one-way ANOVA tests.

Results : A total of 72 measurements were made. Most notably between brands, 23-gauge Alcon trocars (40mmHg endpoint1:41.5±9.2 exchanges; 40mmHg endpoint2:100±0 exchanges; 60mmHg endpoint1:45.8±2.8 exchanges ; 60mmHg endpoint2:100±0 exchanges) demonstrated significantly greater competence (p<0.01 for all comparisons) at both 40 and 60mmHg than their 23-gauge counterparts in B/L (40mmHg endpoint1:16.3±7.5 exchanges; 40mmHg endpoint 2: 60.8±17.2 exchanges; 60mmHg endpoint1:12.3±3.8 exchanges; 60mmHg endpoint2:56.0±17.6 exchanges) and DORC (40mmHg endpoint 1:16.2± 5.5 exchanges; 40mmHg endpoint 2:55.5±4 exchanges; 60mmHg endpoint1:16.5±6.6 exchanges; 60mmHg endpoint2: 45.3±5.0 exchanges). However, at the 25- and 27-gauge sizes, there were no significant differences in competence between trocar brands at either pressure (p > 0.05).

Conclusions : Based on the findings of this study, 23-gauge valved trocars from B/L and DORC exhibit a significantly lower threshold for compromise compared to that of Alcon valved trocars, likely attributable to differences in valve placement design. That said, surgeon experience, vitrector preference, and the specific type of surgery performed are the most important considerations in the choice of vitrector gauge and brand.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.