Leading Surgeons Introduce CONSTELLATION® Vision System
The surgical system's advancements include 5000 cpm probes, duty cycle control, IOP control, xenon illumination, the PUREPOINT® Laser and V-LOCITY® Efficiency Components.
ANDREW E. MATHIS, PhD
Alcon, Fort Worth, TX, recently sponsored 2 symposia to introduce the company's new CONSTELLATION® Vision System for vitrectomy surgery. These symposia, held at the Retina Society meeting in Scottsdale, AZ, and at the American Society of Retina Specialists (ASRS) in Maui, HI, brought together leading vitreoretinal surgeons who discussed the CONSTELLATION® system's numerous technological advancements and clinical experiences in terms of:
- system architecture
- efficiency components
- cut rate and duty cycle
- IOP control
- minimally invasive vitreoretinal surgery (MIVS) techniques and technologies
- laser technology
"This very innovative technology has allowed Alcon to rethink, rework, and re-engineer the entire vitreoretinal system from every point of view," said Donald J. D'Amico, MD, professor and chair of ophthalmology at Weill Cornell Medical Center in New York, who chaired the symposium at the Retina Society.
The intuitive, touch-screen user interface of the CONSTELLATION® Vision System.
Kirk Packo, MD, who chaired the ASRS symposium, gave a short history of vitrectomy before discussing the advanced vitrectomy probe technology available with the CONSTELLATION® Vision System. "We could stop at this point and say we've got some really good machines right now, do we really need another vitrectomy machine?" said Dr. Packo, chairman of ophthalmology at Rush Medical College. He noted, however, this was not replacement technology, but new technology. A summary of the presentations follows.
|The information presented was written by Andrew E. Mathis, PhD, medical editor, Retinal Physician. The views expressed are those of the author and do not necessarily reflect the views of Alcon or the particular surgeons mentioned.|
In discussing the system's architecture, Steve Charles, MD, of the Charles Retina Institute in Memphis, noted that the fluidics system provides added features to traditional vitreoretinal technologies such as proportional reflux, as well as micro-reflux, for all aspiration tools, and offers a safer work environment. "With aspiration flow-limiting, there's actually monitoring of the flow, and you can limit the flow rate," Dr. Charles said. "That has tremendous advantages when working near the retina."
Dr. Charles, who presented at both symposia, noted that the CONSTELLATION® high-speed (5000 cpm) ULTRAVIT® vitrectomy probes are available in 20-, 23- and 25-gauge. While earlier 25-gauge instruments generally received the criticism that they were too small for complicated cases, the 25-gauge ULTRAVIT® probe may address such performance concerns. "What's fascinating is how similarly the 23-gauge and the 25-gauge systems perform," Dr. Charles said. "It's interesting that there's a convergence of the fluidics performance."
Dr. Charles admitted to preferring 25-gauge to 23-gauge and asked, in the wake of the CONSTELLATION® system, whether 23-gauge surgery would continue to be deemed as necessary. During the question and answer period that followed both symposia, his colleagues offered diverse opinions on the question of proper gauge. George Williams, MD, of the Beaumont Eye Institute in Royal Oak, MI, quipped that it was "way too early to be existential," but he advocated 23-gauge instruments. John S. Pollack, MD, of Illinois Retina Associates in Chicago, commented on the difficulty of going back to 25-gauge after using the current ACCURUS® 23-gauge probe. "At this point in time, you can't make a 25-gauge probe that's as stiff as a 23-gauge probe, along its entire length. So, I believe that 23-gauge instruments currently represent a beautiful "sweet spot" in terms of desirable stiffness, flow, and the ability to reproducibly create reliably leak-free wounds," he said.
BEYOND CUT RATE AND VACUUM
One of the key features of the CONSTELLATION® system is that it allows surgeons control over duty cycle, said Pravin Dugel, MD, of Retinal Consultants of Arizona in Phoenix. In presentations at both symposia, Dr. Dugel defined duty cycle as the percentage of time the port is open in a given cut cycle. "Since the birth of vitrectomy, we as surgeons have had control over only two surgical parameters: cut rate and vacuum," Dr. Dugel said, pointing to duty cycle as an all-important third parameter now in the physician's control. "It's a very elegant way to either increase or decrease flow without changing vacuum or cutrate parameters."
Explaining the three duty cycle setting in the CONSTELLATION® system — SHAVE, a closed bias setting, where the port is closed a majority of the time; CORE, an open bias setting, where it is open most of the time; and a 50-50 duty cycle — Dr. Dugel also emphasized the importance of what he called "effective flow vitrectomy," or the least amount of flow to do the job.
The CONSTELLATION® system also aids the surgeon in controlling intraocular pressure (IOP) during vitreoretinal surgery. "The machine actually checks the resistance of the line as it is priming the device so that it can keep the pressure within 2 mmHg the whole time," said Peter Kaiser, MD, of the Cole Eye Institute at the Cleveland Clinic, who spoke at the Retina Society meeting. "Pressure control is such that the CONSTELLATION® system monitors and can adjust automatically to any drop in pressure through the infusion tubing, as well as flow changes in the eye," he said.
Information on the operative pack or other consumables used during surgery is recorded by the bar code reader, avoiding the need for manual input by the scrub/circulator.
Noting that change in gauge size will affect flow rates and, thus, IOP, Dr. Kaiser compared the advantages of IOP control with the CONSTELLATION® to that of earlier systems, such as Alcon's ACCURUS® system and its vented gas forced infusion (VGFI). "This is very important in many diseases," Dr. Kaiser said, "but in particular in diabetics when we're trying to prevent bleeding from sudden changes in pressure."
IMPROVEMENTS IN ILLUMINATION
The CONSTELLATION® system uses mirrors, rather than beam splitting, to deliver light through the system's illumination ports. At the Retina Society meeting, David Boyer, MD, of Retina-Vitreous Associates Medical Group in Beverly Hills, CA, described how this works in practice.
Dr. Boyer described the CONSTELLATION® system's fibers, emphasizing their superior bonding and how the CONSTELLATION® system's new sapphire wide-angle illuminator provides 106° of illumination. "The system utilizes RFID technology to automatically recognize the illuminator type and gauge size and sets the light output to gauge specific settings. The system will default to a light output between 8 to 10 lumens," Dr. Boyer explained.
One of the most attractive benefits offered by the advanced technology of the CONSTELLATION® system is that it makes retina physicians "better surgeons," said Dr. Williams, in his presentation at the Retina Society meeting. "But we want to become more efficient surgeons as well." Dr. Williams spoke on the advantage of the CONSTELLATION® system's V-LOCITY® efficiency components, which include:
• Setup components — Push prime, ENGAUGE® radio frequency identification (RFID) technology, integrated pressurized infusion, articulating tray arm, bar code scanner, and video directions for use
• Surgical components — Auto fluid/air exchange valve, auto gas fill, integrated pressurized infusion, integrated PUREPOINT® laser, and proportional diathermy
• End of case reporting components — Laser form, case form, consumables list, case metrics for anterior and posterior, and laser procedures.
In discussing the advantages of these components, Dr. Williams cited the articulated tray arm of the CONSTELLATION® system, which allows for the efficient setup of instruments, and the auto infusion valve, which simplifies fluid/air exchange by eliminating the stopcock. In addition, Dr. Williams said, "the auto gas fill allows us to minimize the waste that we see every day in the operating room when we draw up gas" through an automatic purge and fill of the syringe. In the CONSTELLATION® Vision System, Dr. Williams pointed out, "the gases are mounted on the back of the machine; they feed directly in."
23-GAUGE WOUND ANALYSIS CASE SERIES
Demonstrating the ease with which reliably leak-free 23-gauge wounds may be created, Dr. Pollack presented data from his retrospective study of 50 vitrectomies using the Alcon 23-gauge single entry cannula system. Dr. Pollack's study compared a series of 11 cases performed using a 5°/90° biplanar insertion technique to a subsequent series of 38 cases using a 5°/30° biplanar insertion technique.
Dr. Pollack pointed to the effectiveness of the 5°/30° biplanar technique, which produced leak-free sealing of 100% of 117 consecutive sclerotomies compared to the need for suturing of 6% of sclerotomies in the 5°/90° insertion technique series.
PUREPOINT® LASER TECHNOLOGY
Timothy Murray, MD, of the Bascom Palmer Eye Institute in Miami, discussed the PUREPOINT® laser technology embedded in the CONSTELLATION® Vision System. He described the 4 keys to the superiority of PUREPOINT® laser technology:
- voice confirmation
- multifunction foot-pedal application
- RFID technology
- dual-laser attachment ports
The CONSTELLATION® features auto gas fill directly on the front of the console.
He observed that PUREPOINT® laser's thin-disk technology photocoagulator "enhances the surgeon's interface to laser delivery through a combination of unique features." To back up his assessment, Dr. Murray presented a case series in which patients with diabetic macular edema underwent 3-part pars plana vitrectomy with internal limiting membrane peeling. Dr. Murray attributed the success of the technique he used to PUREPOINT® laser technology.
At the ASRS meeting, Dr. Packo asked Dr. Murray about the response at Bascom Palmer to the CONSTELLATION® system.
"I think they were thrilled," Dr. Murray responded. "There are some phenomenal advances that will have significant impact in the efficiency of our operation rooms."
Not the least of the impacts is cost-effectiveness. Responding to another question, Dr. Dugel said he believed the CONSTELLATION® system's efficiency could help practices reduce workload.
"I had some doubt," one audience member at ASRS admitted, summing up the general reaction to the CONSTELLATION® system, "but after testing, I believe we are at the forefront of a revolution." RP