Is it Time to Upgrade Your Phaco System?

Recent fluidics improvements may mean a "yes" for your practice.

BY LESLIE GOLDBERG, ASSOCIATE EDITOR

The recent introduction of three new phaco systems may mean that it might be time for you to take a look at upgrading from your older systems. Innovations made to the fluidics controls in the Infiniti Vision System (Alcon, Fort Worth, Texas), the WhiteStar Signature System (Advanced Medical Optics, Santa Ana, Calif.) and the Stellaris (Bausch & Lomb, Rochester, N.Y.) represent advances in technology that many surgeons could find appealing.

The Infiniti Vision System

"Fluidics is the foundation of being able to deliver phaco energy safely and effectively to the lens," says Tom R. Walters, M.D., in private practice at Texan Eye Care, Austin, Texas. "In that regard, the fluidics is one of the better parts of the Infiniti system." Dr. Walters is an Alcon consultant, but not for this technology.

Dr. Walters describes a recent phacoemulsification case that he performed using the Infiniti on a lens that he thought would otherwise be impossible to remove using phaco. "It was an extremely large dense nucleus, the patient had pseudoexfoliation and there was significant zonular laxity," says Dr. Walters. "Without the combination of efficient torsional ultrasound and the stability of the advanced fluidics provided by the Infiniti system, I would not have been able to perform successful phacoemulsification on this patient. The good thing about the fluidics in this case is it allowed me to keep a balanced chamber during the entire procedure without bouncing the capsular diaphragm, which is very common in patients with pseudoexfoliation."

Dr. Walters was able to use the phaco power of the torsional ultrasound within the capsular bag without tugging on the nuclear material and without bouncing the bag, He says that this made for a very "capsular bag-neutral" procedure.

"Torsional ultrasound is a relatively new addition to the Infiniti handpiece," says Dr. Walters. "Instead of moving the tip of the probe forward and backward, which is linear, it ‘waggles’ the probe back and forth. This makes for an extremely efficient way of delivering energy to the lens."

"In the case I described — an eye set up for complications — the stability of the fluidics allows me to address difficult cases with a high degree of comfort. Certainly, torsional phaco works in concert with the Infiniti's fluidics that Alcon has perfected over many years of development," says Dr. Walters.

Another aspect of this platform is that the fluidics is itself customizable in addition to customizing phaco power. "At different stages of the procedure, we can automatically adjust to predetermined settings of irrigation, aspiration rate, vacuum, aspiration delay and post-occlusion surge suppression. It is very customizable based on the independent doctor's technique and the type of lens that the doctor is trying to remove," says Dr. Walters.

Dr. Walters says that the fluidics of the Infiniti system allows for an extremely stable environment within which torsional ultrasound excels. "When the foot pedal is engaged to initiate phacoemulsification, I can rely upon the [steady] fluidics of the Infiniti to keep the anterior and posterior chambers and capsular bag balanced in a stable position while the torsional ultrasound efficiently removes even the most difficult lenses," he says.

The WhiteStar Signature System

"A current trend in technology is to work hard at producing fluidics without inducing extra unoccluded vacuum," says Randall Olson, M.D., John A. Moran Presidential Professor and Chair of the Department of Ophthalmology and Visual Sciences at the University of Utah Health Sciences Center. "We have always been taught that in peristaltic systems there is no vacuum until you occlude. Then when you do occlude, you get vacuum buildup. This is true at lower levels of flow, but at the levels of flow most people use today, the peristaltic pump creates vacuum in order to gain that flow even though you are not occluded."

Dr. Olson says that one way to improve fluidics, and in particular minimize post-occlusion surge, is to decrease the bore and stiffness of the tubing. "When you decrease the bore of the tubing, you increase the amount of unoccluded vacuum you need. One reason that peristaltic systems have been more popular than venturi systems is that with venturi, you have active vacuum at the tip all the time. It feels a little more dangerous. You are unoccluded and you grab something and have immediate high vacuum holding the capsule or iris in place. So, you are more likely to tear the capsule. There is no question that is a perceived advantage of a peristaltic system."

But, says Dr. Olson, "If we continue to improve fluidics by decreasing the bore and the length of the tubing, both of which indeed increase resistance and make post-occlusion surge (POS) less likely, I think there may be a potential negative and a safety issue."

Dr. Olson, a consultant for AMO, says that company's WhiteStar Signature has been specifically developed to improve fluidics without simply decreasing the bore and length and the amount of resistance. Dr. Olson recently co-authored a peer-reviewed article that bears out this position. Vacuum and flow rates of three phaco systems were compared in tests conducted on cadaver eyes. POS was found to be lowest for the Signature.¹

The Signature has a venturi module as well as a peristaltic module. "The system allows you to combine the two and also have the ability to switch between a peristaltic pump and venturi pump on the fly," says Dr. Olson "You may have venturi kick in immediately after you have occlusion, for instance. Then, as soon as you have an occlusion break, you can immediately go back to peristaltic. All of these things can be done within milliseconds."

Dr. Olson says this will allow for interesting versatility. "You can now switch between the speed of venturi and the safety of peristaltic. How important is that going to be? That remains to be seen. I think there may be some efficiency and some safety issues tied in with this, but it's too early to tell," he concludes.

Dr. Olson also likes the OZiL-like ultrasound handpiece which is new to AMO. "They now have their own version of the side-to-side OZiL (Alcon). Only AMO's, rather than going side-to-side, makes an ellipse. The principles are relatively similar but the difference is how they created the side-to-side motion. Unlike OZiL, you can use the AMO piece with a straight tip. It is quite effective no matter what kind of tip you use." Dr. Olson says that clinically, it is very effective.

"One other feature of the handpiece is that you can combine a side-to-side mode with a longitudinal mode with the same stroke," says Dr. Olson. "Other handpieces allow you to perform transversal and then add longitudinal strokes as desired. Now, for the first time you can do them as part of the same stroke. Again, only time will tell how important this will be."

The Stellaris System

"Whichever machine you're most comfortable with will always deliver the best outcomes, whether it's an easy or a difficult cataract case," says Joe Gira, M.D., of the St. Louis Eye Laser & Surgery Center, St. Louis. "I believe that the Stellaris (B&L, Rochester, N.Y.) is such a good system because of the fluidics. The stability of the chamber makes it so that the cataract surgery is just a safer procedure."

Dr. Gira says that the worst complication occurs when the posterior capsule is broken. "With a stable chamber, the capsule stays way back; I have not broken a capsule in years," he says. "When you have an unstable chamber, the posterior capsule can easily come into contact with the phaco tip, leading to a broken capsule and vitreous presentation. During difficult cases, it's one less thing you have to worry about. It's just safer."

"The new phaco machines have more advanced software, which allows you to fine tune your procedure," says Dr. Gira. "There are now more settings available to meet surgeon and patient needs — the machine can adapt to you."

Dr. Gira says that one of the big improvements of the Stellaris over B&L's earlier phaco machines is that it no longer needs a nitrogen tank. He says that this improves both staff efficiency and ease of use. In addition, the foot pedal is wireless and is Bluetooth driven. "This is really nice because you can move the pedal around and not worry about the wires getting in the way," says Dr. Gira. "The responsiveness of the foot pedal is amazing. There's no delay and never a glitch.

"One annoying and sometimes catastrophic problem with phaco is when the irrigation sleeve detaches from the phaco handpiece," continues Dr. Gira. "There is nothing to keep that connection in place. This has happened to everyone at some point. When that irrigation port comes off and you're in the eye when that happens, the chamber disappears and you can easily break the posterior capsule."

Without irrigation and fluid to keep the eye inflated, everything collapses and it is a dangerous situation, says Dr. Gira. "B&L has fixed this by putting a luer lock on the irrigation line. It locks to the handpiece and the irrigation line never comes off inadvertently," he says.

Dr. Gira says that time is no longer a factor in his cataract surgeries. He performs a 6-minute routine case. "But," he adds, "What time tells you is that if you get a better machine that cuts the nucleus efficiently, and you can remove the cortex more easily because the chamber is more stable, you are using a machine that is safer and more efficient, which automatically leads to shorter surgical times.

"I've noticed with the formation of our ASC about 1 year ago that all the surgeons operate more efficiently. Our surgical times, as a group, have decreased dramatically due to a large part from a more efficient and safer machine. Besides these improvements, our outcomes are better than ever, with less corneal edema and less inflammation postoperatively, and our complication rate is lower."

The Sonic Wave

However, if you do not perform a high number of complex cataract surgeries, you may not find it necessary to upgrade your system.

Trevor Woodhams, M.D., founder of Woodhams Eye Clinic in Atlanta, has been using the Sonic Wave (STAAR Surgical Company, Monrovia, Calif.) exclusively for about 3 years and says that because he uses the system exclusively he cannot compare it to the newer systems, although he's tried them.

"Most of the lens-based surgery I do is refractive, meaning that I'm not really dealing with hard and difficult cataracts," says Dr. Woodhams. "As far as fluidics, I have the ability to change vacuum or flowrate phaco power on a personalized basis. This is necessary, as we have several doctors using the machine."

Dr. Woodhams says that one one of the biggest advantages of the Sonic Wave is that it is a very cost-effective way of doing lensectomy surgery. "A lot of the bigger companies are looking to maintain a high per-use charge and they do that through making non-reusable tubing and forcing the doctor, who is the consumer, to purchase new cassettes, says Dr. Woodhams. "The improvements in the ability to safely remove a lens are increasingly marginal compared to the high increases in cost. In my opinion, for my clientele, these costs can't be justified."

Dr. Woodhams says that his practice may perform seven to 10 cataract cases in a typical day and use a single set of tubing for all cases. "The single cost per case is very low for us. I know these companies are dedicated to putting out a better product, but for me the improvements are increasingly a very thin line," he says.

"If I were to invest time and money in lens surgery technology, I would put my efforts into improving visibility in the anterior chamber — like putting fiber optic tubes behind the iris," says Dr. Wodhams. "I think all the work on fluidics can only be improved so much. The question should be, ‘How can we make this procedure more atraumatic?’"

Dr. Woodhams says that ultrasound in the eye inherently carries a degree of risk and if there are other ways of using energy to break up the lens — resources should be put there. "If you could find a way to use energy that couldn't break a capsule — that would be a true advance. What I would like to see is how can we make this even more atraumatic and how can we examine the inside of the eye even better in terms of measurements in order to put lenses into the eye," concludes Dr. Woodham. OM

Reference

1. Georgescu D, Kuo AF, Kinard KI, Olson RJ. A Fluidics Comparison of Alcon Infiniti, Bausch & Lomb Stellaris, and Advanced Medical Optics Signature Phacoemulsification Machines. American Journal of Ophthalmology. Volume 145, Pages 1014-1017. June 2008