Optimized implantation of Port Delivery System reduces vitreous hemorrhage
Several modifications to the insertion procedure for the Port Delivery System helped to reduce the rate of postoperative vitreous hemorrhage in the LADDER trial, according to a speaker.
“The optimization involved lamellar scleral dissection to gain access to the pars plana and careful edge-to-edge laser ablation of the pars plana choroid,” William R. Freeman, MD, said at the virtual Association for Research in Vision and Ophthalmology meeting.
The Port Delivery System (Genentech) with ranibizumab is a permanent, refillable intraocular implant. Before the optimized procedure, postoperative vitreous hemorrhage occurred in 50.8% of patients. The insertion procedure included a conjunctival peritomy and a full-thickness stab incision through the sclera and pars plana. The device was inserted, and the incision was closed.
Researchers found the pars plana was the main source of bleeding. An optimized insertion technique was devised, Freeman said, with several key updates to reduce vitreous hemorrhage. A 3.5-mm target length incision is combined with a controlled lamellar scleral dissection brought to the full length by using a caliper marker. Next, a pars plana laser ablation using a 532 nm green laser with 1-second overlapping spots is completed. A 3.2-mm slit knife is inserted through the center of the scleral incision without enlarging it in any way, Freeman said.
The entry is “perfectly sized” to fit the implant. After the improvement was developed, the postoperative rate of vitreous hemorrhage in the LADDER trial decreased to 3.8%, Freeman said.
“The consistency of the procedure is very important to reduce this and hopefully in the larger clinical trial will continue with minimal, if any, vitreous hemorrhage,” he said.
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Freeman WR, et al. Optimization of the Port Delivery System with ranibizumab (PDS) implant insertion procedure in the Ladder phase 2 trial. Presented at: Association for Research in Vision and Ophthalmology annual meeting; June 12, 2020 (virtual meeting).
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