Citation: Benitez-Herreros J, LopezGuajardo L, Camara-Gonzalez C, et al. Influence of incisional vitreous incarceration in sclerotomy closure competency after transconjuctival sutureless vitrectomy. Invest Ophthalmol Vis Sci. 2013;54:4366-4371. DOI:10.1167/iovs.13-12008 PURPOSE. To evaluate the influence that vitreous incarceration may exert on the presence of postoperative conjunctival blebs over sclerotomies after transconjunctival sutureless vitrectomy (TSV). Blebs are formed by incisional leakage due to incompetent closure. METHODS.Experimental study in which 23-gauge TSV was performed in 146 cadaveric pig eyes. Once the vitrectomy was finished, triamcinolone was injected inside the vitreous cavity for staining residual vitreous, one of the superior cannulas was extracted over the light probe, and the other cannula was removed with the plug inserted. Postoperative conjunctival blebs in superior sclerotomies were assessed by anterior-segment optical coherence tomography (AS-OCT) in a masked fashion; nondetectable blebs were classified as grade 0 (B0), thin bleb (half scleral thickness) as grade 1 (B1), and thick bleb (>half scleral thickness) as grade 2 (B2). Postoperative incisional vitreous entrapment was evaluated by slit-lamp photographs in a masked way; no incarceration was classified as grade 0 (V0), thin incarceration as grade 1 (V1), and thick incarceration as grade 2 (V2).RESULTS. Conjunctival blebs were found in 13.7% of the sclerotomies (11.3% bleb-B1, 2.4% bleb-B2). Vitreous incarceration was found in 96.5% of the sclerotomies without bleb (B0), 81.8% of the incisions with bleb-B1, and 14.3% of the wounds with bleb-B2. Vitreous incarceration was significantly associated with the absence of conjunctival bleb (P < 0.001).CONCLUSIONS. Vitreous incarceration in sclerotomies is related to less incisional leakage in our experimental model. Maneuvers that reduce vitreous entrapment, such as the interposition of a nonhollow probe during the cannula extraction, could decrease the sclerotomy closure competency.Keywords: vitrectomy, vitreous incarceration, conjunctival bleb, sclerotomy closure, experimental model D uring the last decade, 23-and 25-gauge transconjunctival sutureless vitrectomies (TSV) have gained popularity and acceptance.1,2 In contrast to conventional 20-gauge sclerotomies, 23-and 25-gauge incisions allow minimally invasive vitreoretinal surgery using smaller sutureless incisions, as compared with conventional pars plana vitrectomy 3,4 ; however, they have been related to higher rates of endophthalmitis and hypotony, due to the occasional lack of incisional closure. 5-7Recently, some authors have studied the conjunctival bleb formation over sutureless sclerotomies after vitrectomy, resulting from sclerotomy occlusion incompetency. [8][9][10][11][12][13][14][15] These studies have identified parameters related to the sclerotomy architecture 11,14 and the surgery 9 as factors involved in the postoperative sclerotomy leakage. However, other factors may influence the sclerotomy closure comp...

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.

Direct visualization is the most effective method for detecting vitreous entrapment. Regarding the imaging techniques, UBM was superior to AS-OCT for identifying vitreous incarceration.

Macular ischemia, which lengthens the distance from the perifoveal vessels to the center of the fovea and may disrupt the normal flow of nutrients by simple diffusion to the photoreceptor line, does not seem to influence on inner segment ellipsoid band nor external limiting membrane integrity. Future studies may evaluate the effect of choroidal vascularization on the photoreceptor layer status to enhance the knowledge about the photoreceptor layer nutrients source.