Effect of interposition maneuver during cannula removal on vitreous incarceration rate in vitrectomized eyes measured by ultrasound biomicroscopy.

Purpose: To evaluate the influence of the cannula removal maneuver on the postoperative incisional vitreous incarceration using an experimental model of vitrectomized eye.
Methods: Prospective, experimental, randomized and observer-masked experimental study in which 23-gauge transconjunctival sutureless vitrectomy was performed through oblique sclerotomies in cadaveric pig eyes. Once the vitrectomy was finished, one of the superior cannulas was removed with the light probe introduced through it, and the other cannula was extracted with the cannula plug inserted. Postoperative incisional vitreous incarceration was evaluated by ultrasound biomicroscopy (UBM).
Results: 60 eyes included. Considering the 60 superior sclerotomies whose cannulas were extracted with the light pipe inserted, vitreous incarceration was observed in 35% of them. On the other hand, 71.6% of the incisions whose cannulas were removed with the cannula plug inserted showed vitreous incarceration (p = 0.00013).
Conclusions: Interposing the light probe through the cannula when it is removed seems to reduce the postoperative wound vitreous incarceration rate in our experimental model.