Energy Output Variability Among Phacoemulsification Tips Using Calorimetry.

Purpose: To determine if using different phacoemulsification (phaco) tips will impact thermal energy output utilizing calorimetry. Methods: The Alcon Centurion was used with the Infiniti OZil handpiece and balanced, hybrid, or MST Dewey A1 mini tip. Settings were 100% power, continuous torsional or longitudinal ultrasound, 0mmHg vacuum limit, and flow rate 12mL/min. Outflow tubing was removed from the handpiece and inflow tubing was manually occluded. The handpiece tip was placed into the calorimeter filled with 50mL of degassed deionized water and ultrasound was initiated for 1 minute. Temperature rise and cumulative dissipated energy (CDE) were recorded; ten trials were performed for each group. Results: Statistically significant differences in energy output, measured in Joules, were found between all three tips in both ultrasound modes. Balanced tips showed the highest output, Dewey tips had the lowest. Hybrid tips had significantly increased output in longitudinal mode, whereas Dewey tips had significantly decreased output in longitudinal mode. No significant differences were seen in CDE between tips in either ultrasound mode, but significant increases were seen in longitudinal mode within each tip. Conclusion: This study demonstrated differences in thermal energy production of three different phaco handpiece tips. This provides insight into how thermal injuries occur and what might cause these differences. Our methodology provides a novel way for accurate energy measurement at the tip, though it differs when compared to external energy production measurements. Surgeons should take into consideration the significant variability in thermal energy created by handpiece tips.