Temperature profiles of sleeveless and coaxial phacoemulsification

Bimanual phacoemulsification for subluxated cataractous lens

Bimanual phacoemulsification has been established as a safe and efficacious means of nuclear emulsification in the past. This case report presents the use of this technique in a man in his early forties, who had subluxated cataractous lenses in both eyes. The technique allowed for effective nuclear emulsification within a closed chamber, providing better control over intraocular events. The report emphasizes the safety and effectiveness of bimanual phacoemulsification in cataract extraction, even in challenging cases like a subluxated lens.

Laboratory assessment of thermal characteristics of three phacoemulsification tip designs operated using torsional ultrasound

Purpose

Ultrasound activation of phacoemulsification (phaco) tips can create considerable thermal energy that may increase the risk of tissue damage during cataract surgery. The purpose of this study was to define the thermal profiles of three phaco tip designs in simulated surgical conditions.

Methods

In this laboratory investigation, sleeved phaco tips (mini-flared Kelman^® tip with aspiration bypass port and Intrepid^® Balanced Tip with aspiration bypass port, and MST A1 bent-mini phaco tip (without aspiration bypass) were tested using an ultrasonic phaco device operated in torsional mode at power levels of 50%, 75%, and 100% amplitude. An automated fixture applied a 30 g load to simulate compression against the incision site, leading to friction between the silicone sleeve and the titanium tip. Temperature was recorded by high rate infrared imaging under conditions of free flow and occlusion, which was simulated by clamping the aspiration line. Data were summarized using descriptive statistics.

Results

Baseline temperatures of ~26°C were observed for all tips. During ultrasonic operation at 50%, 75%, and 100% amplitude, temperatures were lower for the mini-flared and balanced tips versus the bent-mini tip, both when load was applied and during occlusion. The bent-mini tip reached temperatures as high as 70°C during occlusion with load when operated at 100% amplitude, whereas the mini-flared tip remained <50°C, and the balanced tip remained <36°C in all test conditions. For the mini-flared and balanced tips, temperature increases during operation were not markedly different from free flow and no-load conditions when occlusion or frictional events were simulated.

Conclusion

In all experiments for each tip design, increasing ultrasound power was associated with greater increases in tip temperature. Tip temperatures increased with applied load, but marked temperature increases during occlusion were observed only with the bent-mini tip. The balanced tip produced minimal thermal peaks in all tests.