Trocar sleeve adapter accelerates silicone oil injection in real-world vitreoretinal surgery

This retrospective, non-randomised, observational cohort study investigated the efficiency of a novel 23G trocar adapter to accelerate silicone oil (SO) injection during endotamponading vitreoretinal surgery.

A total of 105 eyes were included consecutively. Only 23G procedures were eligible. Indications for SO injection were retinal detachment, recurrent retinal detachment, or SO exchange in eyes with retinal instability using either the high-flow viscous-fluid-extraction accessory cannula as the 23G trocar sleeve adapter (1362.VFE2, Dutch Ophthalmic Research Centre [DORC], Zuidland, the Netherlands; n _{Densiron 68} = 30, n _{DORC Silicone 5000} = 30) or the universal polyvinyl chloride (PVC) infusion tube as the standard method (1279.VFI, DORC; n _{Densiron 68} = 30, n _{DORC Silicone 5000} = 15). Eyes with aphakia, traumatic retinal conditions, or combined surgical procedures were excluded.

Pars plana vitrectomy was performed, and after complete fluid-air exchange, SO was injected. The trocar sleeve adapter group was treated with an injection pressure of 2.5 bar and with the trocar valve removed. The standard group was treated with 4 bar pressure and with the valve left in place. The time needed to achieve functionally complete filling of the vitreous cavity with SO was recorded. Safety outcomes included the number of device disconnection events and the occurrence of any major complications.

Multiple linear regression analysis showed that the injection duration was significantly affected by SO type (β = 342.6, 95% confidence interval [CI]: 270.1-415.1, p < 0.0001), device type (β = 190.3, 95% CI: 117.2-263.5, p < 0.0001), and axial length (β = 40.3, 95% CI: 21.6-59.1, p < 0.0001). Application of the 23G trocar sleeve adapter significantly reduced the injection time needed to fill the vitreous cavity with Densiron 68, from 258.9 ± 74.7 s (PVC; 95% CI: 231.0-286.8; 241.5 ± 78 s [median ± interquartile range]) to 89.8 ± 55.0 s (95% CI: 69.3-110.4; 76.0 ± 50.5 s; p < 0.0001, Fisher's LSD, two-way ANOVA). For DORC Silicone 5000, a time reduction from 773.7 ± 257.7 s (95% CI: 631.0-916.4; 835.0 ± 332.0) to 152.8 ± 44.5 s was achieved (95% CI: 136.2-169.4; 153.0 ± 66.5; p < 0.0001, Fisher's LSD, two-way ANOVA). Comparisons of vitreous volume-adjusted injection durations calculated using the VIVEX formula yielded similar results (both p < 0.0001). Three disconnection events occurred, and all procedures were completed without major complications.

Although the 23G trocar sleeve adapter was developed for SO extraction, it reduced the time required for low- and high-viscosity SO injection by three- and fivefold, respectively. The 23G trocar sleeve adapter thus has the potential to substantially shorten SO injection times in clinical practice, although randomised or crossover study designs will be required for validation.