Bimanual phacoemulsification through 2 stab incisions. A wound-temperature study
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William Soscia1, James G Howard, Randall J Olson
1Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences Center, Salt Lake City, Utah, USA.
Purpose:
To determine the thermal parameters of bimanual ultrasound-based phacoemulsification through 2 stab incisions with a bare aspiration needle.
Setting:
In vitro laboratory.
Methods:
The Sovereign phacoemulsification unit (Allergan) was used in 3 modes in conjunction with the Olson irrigating chopper (ASICO) in 6 fresh human cadaver eye-bank eyes to determine the temperature at which a wound burn would occur. A wound burn was defined as temperature exceeding 45 degrees C, whitening around the wound, or wound contraction.
Results:
One hundred percent ultrasound power was required to create a wound burn in the unoccluded mode in continuous ultrasound and the burst mode. The time to create the wound burn was 160 and 180 seconds in 2 eyes in continuous ultrasound and 42 and 50 seconds in 2 eyes in the burst mode; it was 58 and 70 seconds in continuous ultrasound with complete occlusion and required 80% power.
Conclusions:
The energy necessary to obtain a wound burn during 2-incision bimanual ultrasound-based phacoemulsification with a bare aspiration needle in human cadaver eyes was extremely high. The parameters necessary to create a wound burn in each modality occurred well beyond normal clinical settings and provide evidence that 2-stab ultrasound-based lens extraction can be performed safely with the Sovereign machine.