Many features of the new phaco systems and software aim to help surgeons increasingly focused on avoiding complications in even the most complicated cases
Manufacturers of phacoemulsification systems have been trying to improve both safety and efficiency with every successive upgrade they have released over the last four decades. The recent technological developments continue that effort with more help for surgeons who are especially focused on avoiding complications.
Among the leading systems that aim to allow safer surgery through ever-smaller incisions are phacoemulsification systems from Advanced Medical Optics, (AMO, Santa Ana, Calif.), Alcon, Inc. (Fort Worth, Texas), and Bausch & Lomb (Rochester, N.Y.).
All of the new systems and upgrades include safety improvements, an issue upon which many surgeons have become increasingly focused.
“The speed of [new phaco technology] is less of an issue, particularly when you are talking about a clear lens exchange,” said Randy Olson M.D., professor and chairman, John A. Moran Eye Center, University of Utah, Salt Lake City. “So if you take an extra 20 to 30 seconds to be a little bit safer then I think everybody is recognizing that this is a fair trade-off.”
New needle approach for Infiniti
Among the major phaco systems with the largest amount of safety data collected is the Infiniti Vision System (Alcon), which was launched in 2004. It has been repeatedly upgraded with new power modulations and better fluidics controls. The introduction of the Ozil handpiece technology for the Infiniti in 2006 allowed the side-to-side movement of a curved phaco needle, which some surgeons have described as a more efficient approach for removing nuclear material than traditional longitudinal phaco. Ozil offers both continuous and microburst mode.
Richard S. Hoffman M.D., clinical associate professor of ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Ore., said the new Infiniti software and redesigned phaco tip allows him to occlude the tip from the beginning of the procedure.
“We use a biaxial technique, thus this tip does not have the standard aspiration bypass port (ABP) found on the torsional tip,” Dr. Hoffman said. “This new tip has enhanced our ability to perform biaxial phaco with the Infiniti with better lens purchase during chopping.”
The system also allows coaxial surgery through a 2.2-mm incision, which is possible because with the introduction in recent years of the Infiniti’s more rigid Intrepid tubing on the phaco cassette. The tubing, according to some surgeons who have used it, allows more stable chambers in cases where smaller incisions are made and lower quantities of irrigation fluid enter the eye.
Dr. Olson said the new cassette has tighter tolerances, a smaller bore, stiffer overall tubing that is likely to improve post-occlusion surge. However, it may also increase the amount of vacuum necessary to move flow.
“That sometimes correlates with not having as accurate of flow readings,” he said. He plans to examine those features as part of his ongoing phaco technology research.
John F. Doane, M.D., clinical assistant professor, Kansas University Medical Center, Kansas City, Kan., said the new hardware for the Inifiniti is safer but also more efficient. It has allowed him to perform 20 to 30% more cases than the Legacy (Alcon) or Sovereign (AMO).
The system fits his phacoemulsification approach of supracapsular spinning in most cases, along with high vacuum with phaco power at 30 to 60 percent for normal nuclei.
“We have tried all major systems and found that the Infinity best fit our staff and surgeon preferences,” Dr. Doane said.
WhiteStar Signature tackles post-occlusion surge
The WhiteStar Signature Phacoemulsification System (AMO) was launched in April 2007 to succeed the Sovereign Phacoemulsification System. The new system includes a simplified screen and set-up instructions. The Signature comes with an auto-loading cassette that allows surgeons to switch between peristaltic and Venturi fluidics at any point in the procedure.
The new system includes the Chamber Stabilization Environment control of fluidics to minimize post-occlusion surge while allowing the safe use of high vacuum levels and flow rates. The new system aimed to address the limited maximum vacuum time of the Sovereign that made it difficult to chop hard cataracts. The Fusion Fluidics management allows longer maximum power time.
Olson’s research on surge-control technology, published in the June 2008 issue of the American Journal of Ophthalmology, found that the Signature had the best control of post-occlusion surge of any phaco system, especially among patients near the edge of the treatment range.
“Control of [post-occlusion surge] has been one of the single-biggest features people have been looking for in their phaco machine,” Dr. Olson said, about its role in ocular damage. “Control of that has been the single-biggest safety factor.”
Dr. Olson’s recent research also found that the Signature used the least vacuum—about half the vacuum of other systems, unoccluded—to control flow.
“So somehow it is controlling fluidics without just restricting the diameter of the tubing,” he said.
The system is the only to one to allow the surgeon to program the fluidics’ response to occlusion through a touchscreen cursor.
Y. Ralph Chu, M.D., Edina, Minn., has used all three of the newest phaco systems and he prefers the Signature because of its dual pump capabilities.
“I find that the ability to utilize an advanced peristaltic pump with fusion fluidic software control allows excellent control doing nuclear removal while I find the ability to switch to the Venturi pump on the fly essential for providing excellent cortical clean up and viscoelastic removal,” Dr. Chu said.
Regardless of which new system surgeons opt to try, Chu suggests that any surgeon beginning to use a new phaco system start with the settings that are most familiar to the surgeons standard technique and gradually “branch out” with one variable at a time.
The Surgical Media Center, a dedicated laptop computer, allows further customization.
The computer combines the system’s microscope video camera footage with a display of the phaco settings and a graphic display of the system’s performance. This allows for analysis of the machine response in relation to surgical moves in the anterior chamber.
The Signature includes an unchanged conventional phaco handpiece and another, the Ellips, with transverse tip movement. The Ellips allows both lateral and longitudinal tip movement in an effort to eliminate tip clogging and to reduce repulsion, which Dr. Olson found to be highly effective.
“I was amazed how these fragment just disappeared without it becoming milky or clogging,” Dr. Olson said about his use of Ellips handpiece.
The Signature also includes Increased Control and Efficiency pulse-shaping technology, which was also available on the Sovereign.
Stellaris allows coaxial MICS approach
The Stellaris Vision Enhancement System (Bausch & Lomb) was launched last year as a replacement for the company’s Millennium Microsurgical System. The new system aimed to allow either biaxial or coaxial microincision cataract surgery (MICS), in addition to other new features.
The Stellaris includes a touchscreen to allow simplified and quicker pre-op set-up, as well as new cassettes for both vacuum- and flow-based pumps. The systems’ Advanced Flow Module allows surgeons to change from a peristaltic to a Venturi approach at any point in a cataract procedure, which is an ability that Dr. Olson said has been a great help in his phaco procedures.
The Stellaris includes new wireless Bluetooth footpedal that allows dual-linear control, including extra control when the surgeon uses the Venturi pump.
A new phaco handpiece aims to provide smoother power delivery. The tip excursion has been increased by 25%, which requires lower power settings than were used in its predecessor.
New software released for the system, called Custom Control, shapes the wave of the ultrasound pulses.
The coaxial MICS features include a new tip connected to a new thin sleeve. The 0.5 mm inner diameter of the needle requires high vacuum levels for smooth functioning.
Dr. Olson said the system’s smallest-yet 1.8 mm coaxial MICS technology is very good but added that it’s not yet clear if there are clinical advantages over other system’s 2.2 mm-incision technology.
The Stellaris includes EQ Fluidics Management Technology that aims to better control the balance of aspiration and irrigation. The approach is intended to keep chambers more stable when using either the flow or vacuum systems with the new MICS tip.
For MICS, the system can be fitted with StableChamber tubing, which offers resistance to fluid outflow and a mesh to prevent large pieces of nucleus from clogging it.
Dr. Olson’s reaserch found Stellaris nearly as good as Singature at minimizing post-occlusion surge. The Bausch & Lomb system and the Inifinit were found to require similarly low amounts of vacuum to maintain flow, which is important in avoid ocular damage and surgical complications.
Editors’ note: Dr. Olson has financial interests with Advanced Medical Optics (AMO, Santa Ana, Calif.). Dr. Doane and Dr. Hoffman have no financial interests related to their comments. Dr. Chu has financial interests with AMO and Bausch & Lomb (Rochester, N.Y.).
Chu: 952-835-0965, firstname.lastname@example.org
Doane: 816-327-3259, email@example.com
Hoffman: 541-687-2110, firstname.lastname@example.org
Olson: 801-581-2352, email@example.com