Bent Versus Straight Tips in Micropulsed Longitudinal Phacoemulsification

Stagg, Brian

Bent Versus Straight Tips in Micropulsed Longitudinal Phacoemulsification

Sunday, April 27, 2014: 1:11 PM

Room 151A (Boston Convention and Exhibition Center)

Brian C. Stagg, MD, Moran Eye Center, Salt Lake City, UT, USA

Mohammed A. Farukhi SLC, UT, USA

Randall J. Olson, MD, Univ. of Utah, Dept of Ophth, Salt Lake City, UT, USA

Kevin Kirk, University of Utah, Salt Lake City, UT, USA

Jason D. Jensen, University of Utah, Salt Lake City, UT, USA

Isha Gupta, University of Utah School of Medicine, Salt Lake City, UT, USA

Cecinio Ronquillo Jr., PhD, John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA

William R. Barlow, MD, University of Utah, Salt Lake City, UT, USA

Jeff H. Pettey, MD, Moran Eye Center, Univeristy of Utah, Salt Lake City, UT, USA

Brian E. Zaugg, MD, University of Utah John A Moran Eye Center, North Salt Lake, Utah, USA

Narrative Responses:

Purpose
Cataract surgeons using micropulsed longitudinal ultrasound have debated whether or not it is important for them to use a straight rather than a bent phaco tip. The theory is that longitudinal ultrasound would be more efficient with a straight tip as the force is projected linearly through the tip.

Methods
Hardened porcine lenses were cut into 2mm cubes in a manner shown to be comparable to human cataracts. We conducted phaco experimentation with a micropulsed longitudinal ultrasound machine. Experiments were run with 3 micropulse settings: 7on/5off, 7on/6off, and 7on/7off. All tips were 0.9mm diameter phaco tips with a 30-degree bevel. The tips were either straight or with a 20-degree bend. An individual lens cube was placed inside a chamber filled with BSS and the time required for phacoemulsification of the cube was recorded. This was repeated 20 times for each experimental group. Averages, standard deviations, and student’s T-tests were performed.

Results
The straight tip was significantly more efficient with settings of 7on/5off and trended towards significance with settings of 7on/6off and 7on/7off. With micropulse settings of 7on/5off, the bent tip averaged 3.32 seconds for removal and the straight tip averaged 1.92 seconds for removal (P = 0.01). With micropulse settings of 7on/6off, the bent tip averaged 3.90 seconds for removal and the straight tip averaged 2.50 seconds for removal (P = 0.11). With micropulse settings of 7on/7off, the bent tip averaged 2.83 seconds for removal and the straight tip averaged 2.13 seconds for removal (P = 0.11).

Conclusion
Our results support the hypothesis that micropulsed longitudinal phacoemulsification is more efficient when using a straight rather than a bent tip. This experiment provides objective evidence to answer a question that previously has only been theoretically debated and suggests that cataract surgeons using micropulsed longitudinal phaco should use straight tips.