Take-home message: A survey of cataract surgeons operating with a proprietary phacoemulsification unit explored their use of dual-linear foot pedal control of fluidics and phacoemulsification power.
Reviewed by Timothy P. Page Sr., MD
—The majority of cataract surgeons using a proprietary phacoemulsification unit with dual-linear foot pedal control (Stellaris/Stellaris PC Vision Enhancement System, Bausch+Lomb) are employing and enjoying that option for improving the efficiency and safety of routine and more challenging procedures, according to a global field observation study.
“The dual-linear function gives surgeons on-demand control and separation of phaco and fluidics, and its benefits essentially come down to better performance and greater safety,” said Timothy P. Page Sr., MD, co-chief of anterior segment surgery and professor of ophthalmology, Oakland University William Beaumont School of Medicine, Royal Oak, MI.
What the survey found
Information about whether cataract surgeons operating with the platform were using dual-linear control, how they were using, and what advantages they thought it provided was sought through an online survey sent out to surgeons worldwide.
A total of 32 surgeons reporting on 149 procedures participated. Use of dual-linear control was reported by 28 (87.5%) of the respondents and in 128 (85.9%) of the procedures.
The most common reason why surgeons chose dual-linear control was because of their phaco technique (48.4%), followed by cataract grade (39.8%). Others favored it when operating in eyes with zonulopathy (17.2%) or intraoperative floppy iris syndrome (10.9%).
“Analyses of the surgeons’ responses indicated they seemed to favor the dual-linear versus co-linear foot pedal mode to achieve better surgical efficiency and control and particularly in more difficult cases,” Dr. Page said.
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Techniques used most often
The techniques used most often when operating with dual-linear control were phaco chop (43%) and phaco flip (25%).
“These two techniques align best with having greater dynamic control over phaco and vacuum holding power, and so it is not surprising to find they were used most often by surgeons using dual-linear,” said Dr. Page, who is also in private practice, Birmingham, MI.
The survey also asked surgeons how they programmed the yaw function on their foot pedal for dual-linear control procedures. Their responses showed it was most often set up for independent control of phaco power (44.5%), followed by to allow for extra vacuum (36.7%). The remaining minority (16.4%) programmed the yaw function for complete vacuum control.
Dr. Page noted he uses a quick-chop technique and sets his dual-linear mode so that the yaw movement of the foot pedal brings in extra vacuum when he is in foot position 2.
This approach gives better holdability and reduces the risk of post-occlusion surge, he said.
“I found it interesting that more surgeons used the yaw position for giving them access to using phaco at any level of vacuum in foot pedal position 2,” Dr. Page said.
“With my technique, the opportunity to boost vacuum without going all the way down into foot position 3 helps with chopping and engaging a quadrant to bring it into the central safety zone,” he said. “Then I can go down on the vacuum as I begin phaco, which will reduce the risk of post-occlusion surge.”
Other questions asked surgeons whether dual-linear control had benefit for providing superior functionality and control over a variety of parameters.
Overall, the surgeons felt it had advantages in 97% of the cases they reported on.
Its greatest benefits were for improving holdability (61%), chamber stability (54%), and followability (43%).
Surgeons’ responses showed some also felt it had benefits for reducing chatter (37%) and improving cutting power (29%).
In write-in responses, surgeons mentioned benefits for minimizing post-occlusion surge, controlling vacuum, reducing the volume of irrigation fluid used, and reducing ultrasound power.
Data collected on irrigating fluid use and phaco power corroborated the latter responses. Mean volume of irrigating fluid used was significantly less in procedures performed using the dual-linear versus co-linear technique (66 versus 84 mL, respectively).
In addition, use of the dual-linear mode was associated with a greater than 50% reduction in mean actual phaco time compared with co-linear control (30 versus 68 sec), and about a 30% reduction in effective phaco time (7 versus 10 sec).
“The difference in irrigating fluid volume is noteworthy considering some evidence that putting less irrigating fluid through the eye may translate into clearer corneas, potentially as a result of causing less turbulence,” Dr. Page said.
“Although there may be some confounding of the results for phaco time considering that the dual-linear procedures were more often done using a phaco chop technique,” he said, “the fact remains that phaco time was less using dual-linear control.”
Timothy P. Page Sr., MD
E: [email protected]
Dr. Page is a consultant to Abbott Medical Optics, Alcon Laboratories, and Bausch + Lomb.