Tissue attraction associated with 20-gauge, 23-gauge, and enhanced 25-gauge dual-pneumatic vitrectomy probes.

PURPOSE

To evaluate the influence of different vitrectomy probe gauge sizes and their fluidics, under various vacuum settings, on tissue attraction.

METHODS

An apparatus was designed to model the retinal membrane during vitrectomy. A cantilever beam was constructed from a wire (diameter, 0.076 mm) with a latex strip (simulating ocular membranes) attached at a right angle to its tip. The beam was clamped vertically in a container of balanced salt solution. The port of the vitrectomy probe (20 gauge, 23 gauge, and enhanced 25 gauge) was aligned with the membrane. With the cutter off, the vacuum was increased until the membrane was attracted into the port. The aspiration flow rate was measured with a noninvasive flow meter. Attraction distance, vacuum pressure, and flow rate were recorded.

RESULTS

For any given distance, the 20-gauge probe needed the lowest amount of vacuum and the highest aspiration flow, while the enhanced 25-gauge and 23-gauge probes needed larger vacuum and smaller aspiration flow rates to attract the membrane into the port.

CONCLUSION

The sphere of influence on surrounding tissue was greatest with large-gauge vitrectomy probes. This laboratory model indicated that small-gauge probes could be used to target specific tissues while minimizing the effects on adjacent tissue structures.