Small-gauge surgery maximizes retina outcomes

Take-home

Advancements in retina surgery include small-gauge instrumentation, a small vitrectomy machine, and a surgical microscope with optical coherence tomography.

Dr. Dugel

By Lynda Charters; Reviewed by Pravin U. Dugel, MD, and Paul Hahn, MD, PhD

As retina surgeons review the surgical highlights of 2013, small-gauge instrumentation (27 gauge), a small vitrectomy machine, and a surgical microscope with optical coherence tomography (OCT) attracted much of their attention.

Smaller-gauge vitrectomy systems

Both the introduction of 27-gauge vitrectomy instrumentation and the ability to perform very efficient small-gauge surgery were among the highlights of the year for Pravin U. Dugel, MD.

Historically, the flow of substance into the port and removal of tissue have been problematic and were never efficient as a result of the inability to control duty cycle, which determines the length of time the cutter remains open.

Traditionally, the cutters were spring-based and did not permit control of the duty cycle with ultra-fast cut rates.

“Now, I use a cutter based on a dual-pneumatic system [Constellation Vision System, [Alcon Laboratories],” said Dr. Dugel, clinical associate professor of ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles. “This allows faster cutting in smaller gauges with predictable flow control, which cannot happen with a spring-based cutter.”

“For the first time, our surgeries can be more efficient and facilitate more accurate dissection,” he said.

Paul Hahn, MD, PhD, assistant professor of ophthalmology, Duke University School of Medicine, Durham, NC, also commented on the importance of the smaller-gauge systems.

“Traditionally, 20-gauge instrumentation was used that then progressed to 25- and 23-gauge,” Dr. Hahn said. “Twenty-seven gauge instrumentation has recently become available, although . . . at this time is still limited.”

Currently, he said, it remains to be determined how useful is the smallest gauge instrument. The smaller the instruments, the more flexible they become-which may be a hindrance during surgery.

“Regarding 27-gauge instruments, most surgeons will likely initially use them during surgical cases when that stiffness is not required,” Dr. Hahn said. “With today’s improved wide-angle visualization systems the stiffness of instrumentation is less critical, and I predict continued increased usage of small-gauge vitrectomy.”

Dr. Hahn

Vitrectomy machines

This past year saw the introduction of more vitrectomy systems (such as the VersaVIT, Synergetics USA).

“This is a very small vitrectomy machine that performs with 2,500 cuts per minute,” Dr. Hahn said. “[This system] is easily portable with an attractive price point, and it will be interesting to see what role this unique machine plays in the operating room setting.”

Valved cannulas

Use of valved cannulas has increased over the past year. Valved cannulas were first placed into extensive commercial use by Alcon Laboratories. These cannulas have distinct advantages over non-valved cannulas. Most importantly, they maintain improved intraocular fluid dynamics and stability.

“I now use valved cannulas exclusively,” Dr. Hahn said. “These benefits are not just theoretical. To me, these fluidics benefits are a game-changer that significantly augment stability of the eye and thus safety during vitrectomy.”

Recently, Bausch + Lomb developed valved cannulas with a removable valve that may be useful in circumstances where a valve is not needed.

OCT integration

Dr. Hahn notes the advantages of OCT imaging integrated into the surgical microscope.

“This is becoming more and more of a hot topic because of its obvious benefits in surgery,” he said. Dr. Hahn is working with Dr. Cynthia Toth, professor of ophthalmology and biomedical engineering at Duke University, in developing a prototype microscope-integrated OCT device.

“This is a rapid area of development, and we are continually incorporating additional technology into our device, including swept-source OCT and a real-time tracking system,” Dr. Hahn said.

Two OCT systems for intraoperative use are commercially available:

• One is a handheld system (Bioptigen) whose use was first reported at Duke, but requires halting surgery and moving the microscope out of the field to obtain images.

• Also, Haag-Streit this past year released for European sales an integrated OCT device into its surgical microscope.

“This is an exciting device,” Dr. Hahn said. “Current systems generally are limited to obtaining OCT images at pauses in surgery, and limitations in current technology make real-time acquisition and processing difficult.

“Our Duke prototype system is designed to obtain real-time images during surgical maneuvers and is continually being refined,” he added. “This technology is not far from your operating room, and I predict it will soon change the way we perform surgery just as OCT has transformed the way we see patients.”

Pravin U. Dugel, MD

E: pdugel@gmail.com

Dr. Dugel is a consultant to Alcon Laboratories.

Paul Hahn, MD, PhD

E: paul.s.hahn@duke.edu

Dr. Hahn has no financial interest in the subject matter.

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