Sutureless 23-gauge vitrectomy changing surgical paradigm

Procedure is ‘happy medium’ because incisions are small enough to self-seal but large enough to allow sturdy instruments to enter the eye.

Since its introduction in the early 1970s, vitrectomy has found a role in the treatment of numerous retinal conditions, including retinal detachment, macular hole surgery and diabetic retinopathy. Recently the procedure has undergone a series of revisions, allowing for smaller incisions that do not require sutures and potentially laying the groundwork for a more efficient and patient-friendly procedure, according to proponents of the sutureless technique.

Today, ophthalmic device makers market 20-gauge systems, which require sutures, and 23- and 25-gauge systems, which do not. Among those available in the United States are Bausch & Lomb’s 20- or 25-gauge Millennium system, Alcon’s 20-, 23- or 25-gauge Accurus system, and Dutch Ophthalmic’s 20-gauge Claes and 23-gauge Eckardt systems.

Ocular Surgery News spoke with two surgeons about the evolution of vitrectomy into a sutureless procedure, as well as the risks and advantages of obviating the need for sutures.

Evolution of vitrectomy systems

Judy E. Kim

Before the advent of 25- and 23-gauge vitrectomy systems, performing vitrectomies with 20-gauge instruments had been the standard of care for many years, OSN Retina/Vitreous Section Member Judy E. Kim, MD, said. However, the scleral incision created during 20-gauge vitrectomy was large and there was no effort to make a beveled incision, so it had to be sutured for water-tight wound closure.

According to Dr. Kim, placement of scleral and conjunctival sutures has some drawbacks.

“When we put in sutures, patient discomfort becomes an issue. Patients will feel the sutures, as if they had an eyelash stuck in their eyes. Patients have to endure that sensation until the sutures come out on their own, which typically takes 2 weeks or more,” she said.

“Sutures can also warp the surface of the eye, leading to temporary postoperative astigmatism. In addition, suture-induced granulomatous reaction can rarely occur. Finally, extra time in the operating room is required to close up the sclerotomies and conjunctiva,” she added.

In response to these disadvantages, several companies began to market significantly smaller 25-gauge vitrectomy systems. With these new leaner instruments, surgeons were able to make small, self-sealing incisions that circumvented the need for sutures.

But the systems had their limitations, Dr. Kim said.

“There is a learning curve involved with stabilizing the eye and making a beveled incision. Some suturing may be necessary in the beginning of the transition to the sutureless system, but as we become more proficient, less suturing is needed,” she said.

However, no amount of practice could overcome a second, more serious limitation that was rooted in the equipment itself. In order to fit through the slim 25-gauge cannula, Dr. Kim explained, the new instruments were designed much thinner than before, resulting in increased flexibility and bending of the instruments. As a result, procedures that put stress on the instruments at the sclerotomy sites, such as removal of anterior fibrovascular proliferation, were more difficult to perform, she said.

The fragile instruments presented safety problems as well. In 2004, several physicians in Japan published a report in the American Journal of Ophthalmology about the tip of a 25-gauge vitrectomy cutter snapping off during surgery.

“Although 25-gauge instruments remain useful, care should be taken against rare surgical complications related to their fragility,” the authors concluded.

With these concerns in mind, industry once again redesigned its products and has recently begun to market 23-gauge vitrectomy systems. According to Dr. Kim, the 23-gauge systems may represent a “happy medium,” offering both the sutureless capabilities of 25-gauge systems with the sturdiness of 20-gauge instruments.

By avoiding the need for sutures, both 23- and 25-gauge systems offer a key innovation in vitrectomy surgery. However, Dr. Kim noted that these small-incision sutureless systems do not have a small gauge ultrasound fragmatome.

Retinal surgeons use a fragmatome to dissect hard nucleus lenses that have dropped to the back of eye during cataract surgery.

“Because fragmatomes are currently only available in the 20-gauge size, one of the sclerotomies will need to be converted to 20-gauge size when used in conjunction with small incision vitrectomy, which may add to the cost of the surgery,” Dr. Kim said.

Two-step incisions vs. one-step incisions The most popular vitrectomy systems on the market allow for one-step incisions. In fact, Dutch Ophthalmic, maker of the two-step 23-gauge Eckardt vitrectomy system, has recently introduced an upgrade that converts the product into a one-step system. “Simplicity of entry is desirable, and that’s why a one-step system is a competitive advantage,” Allen C. Ho, MD, said. Judy E. Kim, MD, agreed. “With two-step systems you have to find your wound again in order to put the cannula in. Because the opening is very small and beveled, sometimes you lose sight of it and have to make another valved incision,” she said. However, two-step systems may afford some advantages. “The Dutch Ophthalmic’s system has a plate that assists with stabilizing the eye, which is helpful. Its size allows proper distance away from the limbus for placement of sclerotomy, so caliper measurement is not needed. Also, creation of valved incision may be more consistent, especially for those surgeons in the initial stages of transition,” Dr. Kim said.

Risks of sutureless incisions

While sutureless incisions offer many advantages, they also pose certain risks, Dr. Kim said.

Some surgeons have reported a higher incidence of retinal detachment with 25-gauge vitrectomy while others do not find an increased incidence, she said.

A second possible risk is endophthalmitis because sutureless incisions provide a temporary window of opportunity for pathogens to enter the eye, Dr. Kim said.

“If the opening is not truly watertight or well covered by conjunctiva, organisms may enter the eye more easily, just as clear corneal cataract surgery can increase the risk of endophthalmitis,” she said, noting that hypotony is another risk.

“If the intraocular pressure becomes too low due to the leak through the sclerotomy, then some patients may get small or large choroidal hemorrhages,” she said.

“If the incisions are not made correctly or if the surgeon is not entirely sure about the integrity of the sclerotomies, one should plan on placing a stitch,” she said. “Even though putting a suture defeats the purpose of sutureless vitrectomy, it is safer than risking these various complications. Also, it’s still faster to put a single suture through these 23- and 25-gauge openings because they are, after all, smaller than 20-gauge incisions. I just put one suture though the conjunctiva and the sclera all at once.”

Safe incisions

In light of the potential risks of sutureless incisions, Ocular Surgery News asked Allen C. Ho, MD, a Wills Eye surgeon and an OSN Retina/Vitreous Section Member, how to minimize complications when performing 23- or 25-gauge vitrectomies.

Allen C. Ho

“Sutureless incisions do have definite advantages and potential disadvantages,” Dr. Ho said. “It’s very important that the incision be made very carefully and angled so that we have the best chance of closure of the sclerotomies without sutures.”

Dr. Ho advocated conjunctival displacement — the intentional misalignment of the conjunctival and scleral wounds — for blocking direct access into the eye and thus reducing the risk of infection.

He also said that surgeons must maintain the integrity of the wound when removing their instruments.

“I try not to pull the cannula out alone. I put a solid instrument, such as a light pipe, into the cannula and the pull the cannula out over the instrument that remains in the eye so that there’s a always solid instrument in the eye. That prevents vitreous prolapse.

“Then I remove the instrument, moving the conjunctiva away from the wound back towards its resting position. I massage the wound with a cotton tip applicator to try to promote closure of the angled incision,” he said.

Dr. Ho said he uses subconjunctival vancomycin for all patients who are not allergic.

“My choice reflects that it’s our drug of choice for many of the organisms that can cause infections such as endophthalmitis,” he said.

He does not feel the need to direct his injections away from the sclerotomy site.

“With vancomycin, I’m right there. Sometimes it’s very close,” he said.

For more information:

• Allen C. Ho, MD, can be reached at Retina Service, Wills Eye Hospital, 900 Walnut St., Philadelphia, PA 19107; 215-233-4300; fax: 215-836-1991; e-mail: acho@att.net. Dr. Ho is a paid consultant for Alcon.
• Judy E. Kim, MD, can be reached at the Medical College of Wisconsin, 925 N. 87th St., Milwaukee, WI 53226; 414-456-7875; fax: 414-456-6300; e-mail: judykim@mcw.edu. Dr. Kim has no direct financial interest in the products discussed in this article nor is she a paid consultant for any companies mentioned.

Reference:

• Inoue M, Noda K, et al. Intraoperative breakage of a 25-gauge vitreous cutter. Am J Ophthalmol. 2004;138(5):867-869.
• Andy Moskowitz is an OSN Staff Writer who covers all aspects of ophthalmology.