Transversal ultrasound technology allows safe and efficient removal of all grades of nuclei with minimal energy and stress on the corneal endothelium and other ocular structures.
Transversal ultrasound technology simultaneously can blend the longitudinal and transversal modes, which improves occlusion of the phaco tip by maximizing the effect of both types of tip motion during ultrasonic breakdown of nuclear fragments, he said. This increasingly efficient cutting with transversal ultrasound technology does not require the surgeon to change techniques and permits use of either a straight or curved phaco tip.
This latest-generation technology also reduces the risk of thermal damage in the eye, according to the manufacturer.
The same manufacturer's micropulse phaco technology platform (Whitestar Signature, AMO) features a proprietary fluidics system (Fusion) that "provides increased chamber stability and safety to ensure better patient outcomes," according to the company. The system enhances chamber stability and safety through enhancements in the chamber control systems, combined with the availability of both peristaltic and venturi pump systems that can be switched "on the fly" during surgery.
Ultrasound technology has advanced rapidly from the days of traditional longitudinal ultrasound to micropulse "cold" phaco/power modulation with pulse shaping to the new-generation torsional and transversal ultrasound, said Dr. Steinert.
Ongoing areas of study with phaco technology include improvements in the phaco tip, phaco energy waveforms, tip-fragment interaction, understanding and enhancing cavitation, and the interaction between the mechanical and cavitation forces, he said.
One benefit of the newest ultrasound technology is lateral motion, which is achieved with both torsional and transversal ultrasound. The advantages, Dr. Steinert said, include increased cutting efficiency due to emulsifying lens material in more than one direction, reduced repulsion of nuclear material, increased followability of the nuclear fragments, and, importantly, reduced energy and trauma in the eye.
Torsional and transversal ultrasound differ. With the former, the surgeon can choose between torsional and longitudinal modes. A Kelman-style bent-tip needle is mandatory. In torsional ultrasound, the phaco tip rotates on its axis and therefore has an effect only with a bent tip.
In comparison, with transversal ultrasound, the surgeon can use the transversal and longitudinal modes simultaneously. A straight or bent-tip needle can be used because the phaco tip travels in an elliptical path, in contrast to the simple rotational path of torsional ultrasound.
The striking improvements achieved with this technology are seen when removing moderate (2+) and hard (3.5 and 4+) nuclei. With cataracts of moderate density, there is greater surgical efficiency, and with hard cataracts, there are "dramatic improvements in cutting ability," Dr. Steinert said.
"Generally speaking, [transversal ultrasound technology] produces less ocular turbulence and trauma. The corneas are clearer postoperatively in the short term. Less endothelial cell loss has been seen in the long term. All of this translates into a better experience for patients and surgeons," Dr. Steinert said.
"[Transversal ultrasound technology] facilitates safe and efficient removal of very soft to very hard nuclei with minimal energy and minimal stress on the corneal endothelium and other ocular structures. The system offers the surgeon more tip options and a wide range of parameters with all the advantages of the micropulsing and fluidics control [of the micropulse platform]," he concluded.