A novel approach to sclerotomy closure in pars plana vitrectomy: a pilot study

BACKGROUND: Methods of sclerotomy closure following a vitrectomy, including the use of sutures, have been associated with complications such as inflammation, foreign body sensation, and infection. Here, we test an innovative approach to scleral wound closure following pars plana vitrectomy that involves plugging the wound. We investigated several materials with the intent of using products that were either already approved by the FDA for other types of procedures or were biocompatible patient-derived materials. METHODS: We examined whether scleral wounds could be sealed by a clot or internal “plug” rather than a suture or an external adhesive. We tested patient-derived materials (platelet-rich plasma (PRP) and whole blood) as well as polyethylene glycol (PEG) sealant. Whole blood and PRP were prevented from clotting prematurely using sodium citrate, and were clotted for the study with thrombin. Polyethylene glycol (PEG) sealant was prepared according to manufacturer’s recommendations. We used fresh-frozen cadaveric porcine eyes. We tested several methods to form plugs using the above materials, as well as various methods to deliver the plugs into the sclerotomy incisions. We used a novel technique of manual vitrectomy. Successfully generated and implanted clots were tested for efficacy with the Seidel test. RESULTS: Polyethylene glycol (PEG) sealant fractured during our attempts at molding and inserting the plug. In contrast, both whole blood and PRP yielded successful plugs for insertion. We molded a whole blood clot plug by allowing it to clot inside a 20-gauge angiocath catheter and we successfully delivered it through a 23G trocar. At baseline, no wound leakage was apparent. However, the whole blood clot dislodged during the Seidel test. We successfully molded and delivered a PRP clot plug using a tapered 2-20 μl pipette tip, using MAXGrip Forceps to push it through into the wound. No scleral wound leakage was noted at our baseline physiologic infusion pressure. Furthermore, the PRP clot plug prevented scleral wound leakage up to a pressure of 60 mmHg and was confirmed with the Seidel test. CONCLUSION: Our findings suggest that insertion of a clot plug made from either whole blood or PRP may be an effective strategy for scleral wound closure following pars plana vitrectomy. Further testing in preclinical models is warranted to further refine the materials and methods, since this appears to have the potential to improve the closure of the scleral wounds after pars plana vitrectomy.