System affords efficient phaco, stable chambers

March 15, 2006

Maui, HI?HyperCruise using the Cruise Control device (STAAR Surgical) enables high-vacuum, low-energy phacoemulsification with stable fluid dynamics for cataract removal that is safe, efficient, and results in excellent patient outcomes, reported Elizabeth A. Davis, MD, at Hawaiian Eye 2006.

HyperCruise is a versatile system that can be used with various Venturi and peristaltic pump-based systems as well as with different surgical techniques, including bimanual phaco. Dr. Davis uses it to enhance the Venturi performance of the Millennium Microsurgical system (Bausch & Lomb), which she favors because of its dual linear foot pedal control and excellent fluidics. This set-up allows her to use the flip technique for the majority of cases, excluding those with dense nuclei or in situations where there is increased concern about endothelial damage.

"I primarily use the Millennium because I like the fluidics of that system, but by coupling it with the Cruise Control device, I can use higher vacuum and lower energy that creates the ideal setting for performing the flip technique. With the flip technique I can nearly eliminate the risk of posterior capsule rupture, and HyperCruise has allowed me to broaden the Millennium's use by minimizing the amount of energy delivered in the anterior chamber," said Dr. Davis, clinical assistant professor of ophthalmology, University of Minnesota, Minneapolis.

"Restriction of the internal diameter of the phaco tip is another way to increase resistance in the system to allow use of higher vacuum with reduced risk of post-occlusion surge, but that is accompanied by a need for more phaco energy to fragment occluding nuclear material into smaller pieces. Cruise Control provides high resistance without requiring nuclear material to pass through the circuit's minimum internal diameter, and with a 0.3-mm narrowest internal diameter, Cruise Control provides a greater amount of surge protection compared with any phaco needle on the market," she said.

By increasing fluidic resistance, Cruise Control also helps maintain laminar flow to minimize turbulence that can lead to endothelial injury.

"The infusion bottle needs to be raised when using higher vacuum levels, and that results in an increase in the flow rate. As flow rate increases there is a breakdown in laminar flow that promotes turbulence and ultimately a risk of endothelial damage from swirling particles," she said.

Performing HyperCruise phaco with the Millennium Microsurgical system requires the Custom Control software upgrade and the #D4600 Air Exchange Line, which allows pressurization of the infusion bottle. Any phaco tip can be used, but Dr. Davis indicated she prefers the Chop X1 (MicroSurgical Technologies).

"This particular tip features a flared design that spreads vacuum over a larger surface area, thereby maximizing holding power," Dr. Davis said. "In addition, its minimum internal diameter lies more distally from the end compared with most other flare tips. Therefore, holding power is maintained even when the nucleus is deeply impaled."

When performing HyperCruise with the Millennium, vacuum is set at 325 to 400 mm Hg and Dr. Davis uses low phaco energy settings in burst mode. The power level is set between 10% and 30%, and for power modulation, she uses a "hyper-pulse" setting of 55 pulses/sec, which is equivalent to a 58% duty cycle. Vacuum bottle height is 50 cm and aspiration control is off.