Abstract
Purpose: :
To evaluate the efficiency, safety, and feasibility of a 27-gauge instrument system for transconjunctival microincision vitrectomy surgery (MIVS).
Methods: :
We developed a 27-gauge instrument system that includes a vitreous cutter, an infusion line, membrane forceps, chandelier fibers, laser probes, and a trocar-cannula system. The infusion and aspiration rates were evaluated using balanced saline with different aspiration powers. The duty cycle of the 27-gauge vitreous cutter was evaluated based on frame-by frame analysis using a high-speed imaging camera and compared with that of a conventional 25-gauge cutter with different cutter velocities. In a pilot study, 28 eyes of 28 patients underwent transconjunctival 27-gauge MIVS for a variety of vitreoretinal diseases, including idiopathic epiretinal membrane (n=14), vitreous biopsy (n=4), macular hole (n=3), diabetic vitreous hemorrhage (n=3), diabetic traction retinal detachment (n=3), and macular traction syndrome (n=1). Surgical outcomes including anatomic success, visual recovery, and postoperative wound-sealing related complications were evaluated.
Results: :
Although the infusion and aspiration rates of the 27-gauge system were 30% lower than that of the 25-gauge system, the 27-gauge cutter duty cycle, 61% at 1,000 cuts/minute (cpm) and 38% at 1,500 cpm, was equal to or better than that of the conventional 25-gauge cutter (62% and 28%, respectively).Based on fluid dynamics analysis, the vented gas-forced infusion can be set in the range of 20 to 30 mmHg for safely controlling the intraocular pressure (IOP) during 27-gauge vitrectomy. Anatomic success was achieved in all study eyes (100%); 21 eyes (70%) had visual recovery exceeding 0.3 logMAR unit using the 27-gauge system. No eyes required conversion to larger gauge instruments intraoperatively. All sclerotomies self-sealed without hypotony (IOP ≤7 mmHg) from 1 day postoperatively.
Conclusions: :
The fluid dynamics and cutting efficiency of the new 27-gauge system are similar to that of the conventional 25-gauge system. Transconjunctival 27-gauge MIVS is feasible and safe for selected vitreoretinal disorders.
Keywords: vitreoretinal surgery