Iatrogenic retinal breaks caused by infusion fluid during pars plana vitrectomy

CARING: Cannula for Alleviation of Retinal Injury Caused by Needle Fluidic Gashing

Infusion-related iatrogenic retinal breaks (IRBs) are a significant complication in vitrectomies, particularly when smaller-gauge cannulas are used during fluid infusion. Using two-dimensional finite element analysis (FEA), we analyzed forces exerted on the retina from different cannulas: traditional 25-gauge, 20-gauge, 23-gauge, and 27-gauge, then investigated four alternative new cannula designs: (A) oblique orifices, (B) external obstruction, (C) side ports, and (D) perpendicular orifices. The analysis revealed that the standard 25-gauge cannula had a force of 0.546 milli-Newtons (mN). Optimized cannulas demonstrated decreased forces: 0.072 mN (A), 0.266 mN (B), 0.417 mN (C), and 0.117 mN (D). While all the designs decrease fluid jet force, each has unique challenges: Design A may complicate manufacturing, B requires unique attachment techniques, C could misdirect fluid toward the lens and peripheral retina, and D requires a sealed trocar/cannula design to prevent unwanted fluid ejection. These four innovative cannula designs, identified with detailed engineering simulations, provide promising strategies to reduce the risk of IRBs during vitrectomy, bridging the gap between engineering insights and clinical application.

INFUSION-ASSISTED EVACUATION OF SUBMACULAR HEMORRHAGE

PURPOSE

To report a novel surgical technique for evacuating submacular hemorrhage using the infusion stream of a 25-gauge vitrectomy system.

METHODS

Surgical case and video.

RESULTS

A 54-year-old man was taken to the operating room for a total hyphema, nonclearing vitreous hemorrhage, and elevated intraocular pressure after multiple tractional retinal detachment repairs by an outside surgeon. Intraoperatively, the hyphema and vitreous hemorrhage were cleared, and the source of bleeding was discovered to be an avulsed vessel through a pre-existing retinal break just superior to the optic nerve. A large submacular hemorrhage was also present that was unable to be drained through the break by aspiration alone. With the vitreous cavity under fluid, the infusion cannula was manipulated to guide the infusion stream onto the macula. The stream was directed in a distal to proximal manner toward the retinal break, and the submacular blood was successfully expressed out through the break. Postoperatively, the retina remained attached with almost complete resolution of the submacular hemorrhage.

CONCLUSION

Using the mechanical pressure of the infusion stream can be an effective method for evacuating large subretinal hemorrhages.