Determining optimal ultrasound off time with micropulse longitudinal phacoemulsification

作者：Jensen Jason D; Kirk Kevin R; Gupta Isha; Ronquillo Cecinio Jr; Farukhi M Aabid; Stagg Brian C; Pettey Jeff H; Olson Randall J^*

来源：Journal of Cataract and Refractive Surgery, 2015, 41(2): 433-436.

DOI：10.1016/j.jcrs.2014.12.033

PURPOSE: To evaluate the optimum off time for the most efficient removal of lens fragments using micropulse ultrasound (US).
SETTING: John A. Moran Eye Center Laboratories, University of Utah, Salt Lake City, Utah, USA.
DESIGN: Experimental study.
METHODS: Porcine lens nuclei were soaked in formalin for 2 hours and then cut into 2.0 mm cubes using the Signature US machine with a bent 0.9 mm phaco tip with a 30-degree bevel. The on time was 7 milliseconds (ms), and the off time was varied from 2 to 20 ms in 2 ms steps. Phacoemulsification efficiency (time for fragment removal) and chatter (number of times the fragment bounced from the tip) were measured.
RESULTS: A nonsignificant linear increase in efficiency was observed with 2 to 6 ms of off time (R-2 = .87, P = .24). A significant linear decrease in efficiency was observed with 6 to 20 ms (R-2 = .74, P = .006).
CONCLUSIONS: With micropulse longitudinal US, 6 to 7 ms of off time was as efficient as shorter off times; longer off times (8 to 20 ms) showed decreased efficiency. Chatter was minimal and statistically similar throughout. To maximize phacoemulsification US efficiency, an off-time setting of 6 ms is recommended.

• 出版日期2015-2