A comparison of small-gauge instrumentation reveals some subtle differences in surgical technique.
Take-home message: A comparison of small-gauge instrumentation reveals some subtle differences in surgical technique.
By Laird Harrison; Reviewed by Jared Nielsen, MD
West Des Moines, IA-Smaller-gauge instruments do not significantly lengthen the amount of time required for vitrectomy, and increase the frequency of immediate wound closure, according to Jared Nielsen, MD.
Dr. Nielsen, of the Wolfe Eye Clinic in West Des Moines, IA, presented a case series comparing 25- and 27-gauge instrumentation (Alcon Constellation Valved Trocar).
“Patients universally seemed to really like the 27-gauge surgery,” he said. “Even though we’re using much smaller instruments, surgery doesn’t take appreciably longer.”
Dr. Nielsen said he was immediately interested when he heard about the smaller instruments, but worried that the surgery would be more time consuming. Once he started using them, he did find some differences in technique.
“They’re a little bit more flexible,” he said. “They’re a little more apt to bend. It takes some getting use to. But after about 20 cases, it became my gauge of choice. Now I do all of my less complex cases with 27-gauge.”
For example, the size of the light pipe is smaller. By increasing illumination at the source of the light, he found he could see well enough. In addition, he had to be more vigilant to remove anterior vitreous.
Overall he had the impression that surgery with the 27-gauge tools was taking about 10 minutes longer than with the 25-gauge tools. To see whether his impression was correct, Dr. Nielsen carefully documented surgery times and outcomes in a series of cases done with each of the two sizes.
For the comparison he chose only relatively simple procedures: epiretinal membranes, macular holes, vitreomacular adhesion, non-clearing vitreous hemorrhage, vitreous opacity, vitritis and endophthalmitis.
He excluded more complex cases with retinal detachment, retained lenses, and dislocated IOLs.
He completed a consecutive series of 67 cases with each instrument size. More than 85% of the patients in the 27-gauge group were pseudophakic, compared with 78% in the 25-gauge group. In the 25-gauge group, 8.5% had previous vitrectomies, compared with 3.6% of the 27-gauge group.
Dr. Nielsen found that the mean time for each surgery was only 35 seconds longer with the 27-gauge instruments. That difference was not statistically significant (p = 0.6249).
The surgery resulted in 201 wounds in each group. In the 27-gauge group, 198 of the wounds closed immediately, while in the 25-gauge group 193 closed immediately.
Counter incisions were required in 5 of the 25-gauge group, and 1 of the 27-gauge group.
“The 27-gauge instruments are well-made,” Dr. Nielsen said. “They’re well-designed. And they’re efficient. That’s the reason there is not a huge difference in our hands. In theory vitreous removal would be prolonged with the smaller instruments, however vitreous removal is only one component of the entire procedure. For me, most aspects of the surgery are not any different.”
Overall, his work with the small-gauge instruments has left him encouraged.
“I get really excited about this technology because I know it’s only going to continue to improve,” he said.
Jared Nielsen, MD
This article was adapted from Dr. Nielsen’s presentation at the 2015 meeting of the American Society of Retina Specialists. Dr. Nielson receives research support from Alcon Laboratories.