Comparative Thermal Characterization of Phacoemulsification Probes Operated in Elliptical, Torsional, and Longitudinal Ultrasound Modalities
Narrative Responses:
Purpose
To characterize the thermal behavior of phacoemulsification probes operated in elliptical, torsional and longitudinal ultrasound modalities using advanced temperature recording technologies
Methods
High rate infrared imaging and micro-thermocouple measurements are used to detect surface temperature of sleeved phaco needles activated in elliptical, torsional and longitudinal modalities. Inter-layer frictional heat build-up was studied for sleeved needles using a calibrated load to simulate conditions of suitably sized clear corneal incisions. Low-flow/low-cooling operating condition was invoked by simulating occlusion events
Results
Needle-sleeve friction using a calibrated load extending between 4 and 8 mm proximal to the needle tip showed increase in temperature up to 48° C for elliptical mode, 49° C for longitudinal mode and 38° C for torsional mode. Simulated occlusion events produced comparable temperature increases for elliptical and longitudinal modalities; both higher than with torsional. Elevated temperature profiles along the entire length of the tip was highest for elliptical, followed by longitudinal, then torsional
Conclusion
Loads applied between the needle and sleeve at the incision site creates frictional heat that increases temperatures where that contact is made. Elliptically and longitudinally operated phacoemulsification probes exhibit similar thermal output. Torsional vibration mode exhibits a reduced thermal footprint when compared to elliptical and longitudinal phacoemulsification modalities