Phaco system combines previous technology stages

Many technological features of this unit increase surgeon's control

By Chet Scerra

The cataract surgery bar has been raised to a higher level with Allergan's newest entry into the arena of phacoemulsificaiton technology.

With increased sophistication of microprocessor controls, the ability to fine-tune and program fluidics, as well as power modulations, Allergan claims that its new Sovereign system will enable ophthalmologists to perfrom an unprecedented level of minimally aggressive phacoemulsificaiton.

"What this means for the phaco surgeon is an enormous increase in control and safety, and for patients an almost immediate visual rehabilitation and excellent outcome is more likely," said I.Howard Fine, MD, clinical associate professor at Oregon Health Sciences University, Eugene.

Unveiling the instrument at the recent Royal Hawaiian Eye Meeting, Dr. Fine told listeners that Allergan's new system takes from the best of several previous stages of technological development.

Demonstrating the Sovereign's capabilities via a videotaped phacoemulsification procedure performed on an average nucleus, Dr. Fine said that he uses a chopping technique 100% of the time. Doctors watched as he first stabilized the nucleus, and then evacuated it almost exclusively by vaccum.

"Although the vacuum rises to almost 300 mm Hg, I am very frequently in single digits with respect to phaco power," said Dr. Fine. "As a result, the total power going into the eye is a fraction of what we're used to using in previous methods of phacoemulsification. In addition to the lower power, what becomes very obvious is the stability of the anterior chamber because of the fluidics system."

"The Sovereign's new fluidics system is designed to give unsurpassed capsule protecion," said Jim Francese, Allergan Surgical's Marketing Manager. "Its extremely smooth, high-vacuum pump is run by its own dedicated computer and is a completely air-free system. There is no air in the tubing lines or in the cartridge that can cause inaccuracies. It is turbulence-free and trauma-free. We feel that the capsule is extremely safeusing this machine.

"During the surgery, the pump speeds up and slows down automatically to regulate the pressure," aded Francese. "No other pump does that. If you want less vacuum, the pump will actually back up a little and give you less vacuum. All other pumps move forward only. The Sovereign's pump moves forward and backward, dependent on the foot pedal."

Vacuum high, power low

Dr. Fine said that the machine allows the surgeon to disassemble and evacuate the nuclear material quickly, relying almost exclusively on vacuum, with little nudges of phaco power as needed. "In this way we have what everybody wants to have with the emulsification of nuclei, safety and control. I was impressed to see afterward how little phaco power I was using."

"In terms of the ultrasound control, the hand piece also has a dedicated computer that's governing it," said Francese. "In this way, if the surgeon only wants ultrasound power above or below a certain vacuum, that's possible to program in. The machine will turn it on and off automatically.

"The ultrasound comes in only when the surgeon wants it. With other units, the surgeon has to manipulate the foot pedal constantly for the same effect. The pump starts to slow down when you reach the end of the groove so you don't get surging. It's a pump working together with the surgeon."

"The Sovereign unit has better power control that I've see in any of their (Allergan's) machines, so that effective phaco time is significantly diminished," said Tucson ophthalmologist William J. Fishkind, MD. "By use of pulse and burst there's less power being delivered to the anterior segment for any size cataract."

Dr. Fishkind, who is clinical professor ophthalmology at the University of Utah, said that this machine is well designed to prevent postocclusion surge.

"It has wonderful fluidics and all the postocclusion settings, which are going to give us a whole new area to explore and ought to make a significant improvement in the efficiency of the procedure.

"Putting this all together," continued Dr. Fishkind, "it means that the surgery is going to be faster, safer and much more controlled. And, very important, we will have better power utilization and less effective power being delivered to the anterior chamber."

"I've been impressed with the Sovereign's ability to handle dense nuclei," added David F. Chang, MD. Dr. Chang, who is associate clinical professor of ophthalmology at the University of California San Francisco, told Ophthalmology Times that these are the most challenging cases for any phaco machine.

"I utilize a phaco chop technique," he continued. "What's important here with dense nuclei is the ability to get a solid purchase on the nuclear pieces with the phaco tip. This will anchor the nucleus as you chop it. It also gives you the holding force necessary to lift the pieces out of the capsular bag."

"Where the Sovereign unit excels is in the generation of very solid purchase of the nucleus," Dr. Chang said. "It does this through a combination of very high vacuum, giving you the holding force, and the ability to use burst mode in impale the pieces. I've used vacuums of 350 mm Hg with the standard 19-gauge tip, and 450 mm Hg with a smaller 20-gauge tip. The latter is my preference."

Viewer-friendly display

The Sovereign's video monitor has gained praise for its speedometer-type gauges, making it easy to read the settings at a quick glance.

"The screen has a programming mode and an operational mode," explained Francese. "When you're operating, it's showing you what conditions are programmed into the machine, your actual conditions, and your phaco time. It's like an airplane cockpit."

"The trouble with a digital display is that it's hard to see at quick glance," said Dr. Chang. "I think the speedometer gauge concept is nice."

A step forward

"I think Allergan has taken some of the best features from their earlier machines," continued Dr. Chang.

"They've merged the burst mode and the occlusion mode programmability from the Diplomax with the very excellent fluidics that is characteristic of the Prestige unit. The ultrasound mode of the Sovereign is very efficient, and as a result, the effective phaco time (EPT) is extremely low. Even the densest nuclei can be done in less than 20 seconds. Average nuclei can be done in less than 5 seconds. These number are very impressive."

"What please me about this new system is that we now have an ability to take the best of several previous stages of develpment of technology," said Dr. Fine. "The power modulations have been enhance and new and enhanced fluidic capabilities have been added. To me, this is not just more bells and whistles. It represents a true step forward."