Influence of the Interposition of a Nonhollow Probe during Cannula Extraction on Sclerotomy Vitreous Incarceration in Sutureless Vitrectomy

Abstract

To evaluate the effect of the cannula removal technique on postoperative vitreous incarceration using an experimental model of vitrectomized eye. In a prospective, experimental, randomized, and observer-masked study, 118 cadaveric pig eyes were vitrectomized through 23-gauge transconjunctival sclerotomies. Once vitrectomy was finished, one of the superior cannulas was extracted with the illumination probe inserted through it, and the other cannula was removed with a cannula plug inserted. Postoperative incisional vitreous entrapment was evaluated by direct visualization. No vitreous incarceration was classified as grade 0 (G0), thin vitreous entrapment was classified as grade 1 (G1), and thick vitreous strands as grade 2 (G2). Considering the sclerotomies whose cannulas were extracted with the light probe inside, vitreous incarceration was detected in 93.2% (73.7% G1, 19.5% G2) of the incisions. In turn, vitreous entrapment was observed in 95.8% (43.2% G1, 52.6% G2) of the entry sites whose cannulas were extracted with the plug inserted. Statistical analysis showed significant differences when comparing postvitrectomy vitreous incarceration grades in sclerotomies according to the cannula extraction technique (P < 0.0001). Interposing the light probe through the cannula during its removal reduces vitreous incarceration grade in our experimental model. This simple maneuver may decrease complications related to vitreous entrapment, such as peripheral retinal tears and acute endophthalmitis.