Microphacoemulsification with WhiteStar. A wound-temperature study.
PURPOSE: To verify the temperature-induction effect of bimanual ultrasound-based phacoemulsification through 2 stab incisions with a bare aspiration needle and new proprietary technology. SETTING: In vitro laboratory. METHODS: The Sovereign phacoemulsification unit and the WhiteStar system (Allergan) were used in conjunction with the Olson irrigating chopper (ASICO) and a 19-gauge bare phaco needle in 2 human cadaver eye-bank eyes at 100% power unoccluded, 100% power with aspiration completely occluded, and 100% power with aspiration and flow completely occluded. Temperature data were monitored throughout the experiment. Any sign of a wound burn, defined as temperature exceeding 45 degrees C, whitening around the wound, or wound contraction, was the end point. RESULTS: At 100% continuous phacoemulsification power, the temperature did not rise above 27.3 degrees C. When the aspiration line was totally occluded at 100% continuous power, the temperature did not rise above 32.5 degrees C. When flow into the eye and aspiration were completely occluded at 100% power, a wound change and temperature of 45 degrees C occurred in 45 seconds in the first eye and in 29 seconds in the second eye. CONCLUSIONS: Using the Sovereign phacoemulsification unit with the WhiteStar system during 2-stab-incision bimanual microphacoemulsification with a bare 19-gauge aspiration needle in human cadaver eyes, a wound burn could not be produced at the highest energy settings unless all flow into the eye and all aspiration were occluded. These settings were well beyond clinically applicable conditions and provide evidence that microphacoemulsification can be performed safely with the WhiteStar system.