Estudio de la influencia de diversos factores sobre la capacidad de cierre de las esclerotomías sin sutura en vitrectomía microincisionalcomparación de distintos métodos de visualización

Zusammenfassung

BACKGROUND: During the last decade, 23-gauge transconjunctival sutureless vitrectomy (TSV) has gained popularity and acceptance. In contrast to conventional 20- gauge sclerotomies, TSV allows minimally invasive vitreoretinal surgery using smaller sutureless incisions, as compared with conventional pars plana vitrectomy; however, they have been related to higher rates of endophthalmitis and hypotony, due to the occasional lack of incisional closure. Recently, some authors have studied the conjunctival bleb formation over sutureless sclerotomies after vitrectomy, resulting from sclerotomy occlusion incompetency. These studies have identified parameters related to the sclerotomy architecture and the surgery as factors involved in the postoperative sclerotomy leakage. However, other factors may influence on the sclerotomy closure competency, such as the presence of vitreous incarceration, which may work as an incisional plug. In our study, we evaluated the influence that the presence of vitreous incarceration may exert on incisional closure competency after vitrectomy. We also compared ultrasound biomicroscopy (UBM), anterior-segment optical coherence tomography (AS-OCT) and slit-lamp visualization for detecting conjunctival blebs in sutureless sclerotomies after vitrectomy. Due to the invasive nature of our procedure, we used an experimental animal model. MATERIAL AND METHODS: Experimental study in which 23-gauge TSV was performed in 146 cadaveric pig eyes. Postoperative conjunctival blebs and incisional vitreous entrapment in superior sclerotomies were assessed by AS-OCT, UBM and slitlamp in a masked fashion. Non-detectable blebs were classified as grade 0, thin blebs as grade 1 and thick blebs as grade 2. No incarceration was classified as grade 0, thin incarceration as grade 1 and thick incarceration as grade 2. CONCLUSION: 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 non-hollow probe during the cannula extraction, could decrease the sclerotomy closure competency. On the other hand, AS-OCT is the most sensitive technique for detecting subclinical blebs (grade 1) and thus, it may be useful in research for studying the influence that surgical factors and maneuvers may exert on sclerotomy closure capacity after vitrectomy. Direct visualization, that is used in routine clinical practice to determine which sclerotomies should be sutured, is useful only to identify thick blebs (grade 2) after vitrectomy.