Intra-ocular diathermy forceps

Abstract

Purpose: The purpose of this study was to develop intra-ocular diathermy forceps and test them on perfused porcine cadaver eyes.

Methods: We designed two types of 23-gauge intra-ocular bipolar diathermy forceps by modifying commercially available membrane peeling forceps. In the first type, the emitting electrode is connected to one-half of the core and the return electrode to the other half, with one jaw of the forceps attached to each half. In the second type, the emitting electrode is attached to the core and both jaws of the forceps, and the return electrode to the surrounding tube. We compared the new diathermy forceps to conventional intra-ocular diathermy, on perfused porcine cadaver eyes. First-order retinal artery and vein closure was confirmed both by a perfusion study and by histology of the treated vessels.

Results: Type 1 diathermy forceps closed retinal arteries and veins more successfully (five of five and five of five successful treatments, respectively) than Type 2 diathermy forceps (five of five and four of five, respectively) and conventional diathermy (three of five and four of five, respectively). Less energy was used with Type 1 compared to Type 2 and conventional for artery closure (1.5 ± 0.0 versus 4.6 ± 3.3 versus 2.1 ± 0.8 joules, respectively) and vein closure (1.5 ± 0.0 versus 5.4 ± 4.6 versus 2.4 ± 0.8 joules, respectively). Histology of the treated vessels confirmed the perfusion study results.

Conclusion: We designed two types of a new multifunctional intra-ocular instrument with the ability to peel membranes and to grasp, compress and coagulate retinal blood vessels. Both types pose operational advantages compared to current conventional intra-ocular diathermy.

Keywords: coagulation; intra-ocular diathermy forceps; perfusion; porcine eye model; retinal blood vessels; retinal hemangioblastoma.

Figure 1

Fundus photographs and histology slides of coagulated porcine retinal blood vessels. Histology slides (above) and fundus photographs (below) of porcine retinal arteries (labelled a) and veins (labelled v) coagulated with conventional diathermy (panel A), Type 1 diathermy forceps (panel B) and Type 2 diathermy forceps (panel C). In the fundal photographs, the blood columns in the artery and vein have been interrupted by coagulation. The coagulated site and the blood vessel downstream from it show no flow during perfusion of the ophthalmic artery with fluorescein‐stained fluid. The histology slides (magnification 100x; haematoxylin and eosin stain) show coagulated and closed retinal blood vessels following application of diathermy. Retinal detachment is a common artefact because of preparation of the eye for the perfusion study and/or tissue processing for histological examination.