Microincision pushes new frontiers in vitreoretinal surgery

Yusuke Oshima, MD, advocates a 27-gauge approach to achieve an uncomplicated, self-sealing wound. Image: Oshima Y

Along with medicine in general, ophthalmology is evolving toward increasingly less invasive techniques. Cataract surgery has led the way, and at the beginning of the new millennium, vitrectomy has followed with a series of innovations, allowing for smaller, sutureless incisions.

The transconjunctival 25-gauge approach was the first to be introduced, in 2002 by Eugene De Juan, MD. The trocar was inserted through the conjunctiva directly into the sclera, allowing for a reduction of incision size from 1.1 mm to 0.5 mm.

“This approach held several advantages compared to standard 20-gauge vitrectomy. Surgical time was shorter, because we no longer had to open the conjunctiva and then perform a scleral incision that needed suturing at the end of surgery. The smaller access created less postoperative inflammation and led to a more rapid visual recovery. Furthermore, the patients did not experience the foreign body sensation of sutures in the eye. On the whole, the approach was far less invasive, with fewer risks of damaging the retina,” said Paolo Lanzetta, MD, an OSN Europe Edition Editorial Board Member.

However, the first 25-gauge systems presented some drawbacks and limitations. There were problems with inserting the cannulas, the electric vitreous cutter was slow, the instruments were too flexible, and sutureless incisions, though small, were not necessarily watertight and frequently led to postoperative hypotony and endophthalmitis, he said.

“Early series were not always encouraging. Hypotony, retinal detachment and shallow choroidal detachment occurred more frequently than in standard 20-gauge vitrectomy. In quite a few cases, there was a need to suture the incision or to convert to 20-gauge. Endophthalmitis rate was as high as 3% in some of these early series,” Dr. Lanzetta said.

Refinements in 25-gauge technique and technology

With these concerns in mind, industry refined the instruments. The Bausch + Lomb Millennium and Stellaris systems and the Alcon Accurus and Constellation systems now provide state-of-the-art equipment for 25-gauge microincision vitrectomy, with higher-speed vitreous cutters and more efficient endoillumination probes. The design, geometry and sharpness of microincision vitrectomy instruments have also improved.

Techniques have evolved as well. Conjunctival displacement creates a misaligned wound between the conjunctiva and sclera, and, once the conjunctiva moves back, provides a natural protection over the wound. Oblique, beveled rather than straight trocar insertion leads to better wound closure and prevents vitreous incarceration.

“I use forceps to displace the conjunctiva and then perform an oblique, beveled incision parallel to the limbus, followed by a perpendicular tunnel,” said Dr. Lanzetta.

He uses the new Accurus and Constellation systems, but with the old trocars and cannulas.

“The new machines are a great advance, but I don’t see any advantage in the new, funnel-shaped trocar entry. It might facilitate insertion and manipulation, but it causes a higher rate of vitreous incarceration,” he said. “In addition, the old, cylindrical Teflon trocars and cannulas are softer, gentler and less traumatic on the sclera.”

The 25-gauge approach is ideal in macular surgery, according to Dr. Lanzetta, with macular hole the only exception.

“In my hands, hole closure rate is 60% with the 25-gauge approach and 100% with the 20-gauge approach. One possible reason is that you remove a lesser quantity of vitreous when you perform sutureless surgery. Therefore, you have a reduced and less efficient tamponade to close the macular hole. Whatever the reason, I switched back to 20-gauge in these cases,” he said.

For other, more complicated retinal procedures, Dr. Lanzetta still uses the 20-gauge system. “Opening the conjunctiva allows to indent the sclera more efficiently,” he said.

A new, balanced approach

While surgeons were discussing the merits of a 25-gauge vs. 20-gauge approach, a third option — the 23-gauge approach introduced by Klaus Eckardt, MD, in 2005 — rapidly gained consensus. The new system seemed to offer the best of both worlds, combining the advantages of small-incision, sutureless transconjunctival surgery and the versatility and wide spectrum of indications of 20-gauge surgery.

Jong Jian Lee, MD, FRCS, retinal consultant at Raffles Hospital in Singapore, was one of the first surgeons who pioneered 23-gauge microincision vitrectomy in Asia.

“I started nearly 5 years ago, and I use it now in 90% of my patients. I hardly ever use 25-gauge, because it is limited in scope. The instruments are too delicate to handle complex retinal conditions. The 20-gauge approach is great for instrumentation, but since it requires a significantly longer time to get into the eye and a longer recovery time, I use it in a small number of patients, mainly complicated ocular trauma cases,” he said.

Dr. Lee has treated many patients with the 23-gauge approach, using the Alcon Accurus system.

He uses a specially designed pressure plate by DORC International to displace the conjunctiva 1 mm to 2 mm laterally. He then holds it firmly against the sclera while inserting the trocar.

“I do an angulated entry, going in tangentially, 30° to 40° from the surface, about 3.5 mm posterior and parallel to the limbus, followed by a vertical entry. This approach allows the wound to seal better,” he said.

Surgery with this system is fast and safe, according to Dr. Lee. The trocar system protects the vitreous base from the entrance and exit of the instruments.

“It prevents them from causing trauma to the vitreous base, reducing the incidence of retinal tear,” he said.

Also, other complications are rare. Sclerotomies are small and seal well, so leakage, hypotony and infection are not an issue.

“I haven’t had a single case of endophthalmitis in all these years,” Dr. Lee noted.

Iatrogenic cataract may be caused by the cannula touching the lens, but it can be avoided through careful maneuvers.

“Point down vertically toward the posterior pole with your cannula. A wrong angulation may result in contact with the lens, resulting in cataract formation,” Dr. Lee said.

One of the advantages of the 23-gauge vs. 25-gauge approach is the possibility of removing more vitreous. The instruments are stronger, rotate better and can reach further in the periphery. The 23-gauge cutter also has a higher cutting speed. According to Dr. Lee, about 90% of the vitreous can be removed.

Particularly in elderly patients who need gas tamponade and face-down posturing, Dr. Lee said he prefers to put in a temporary suture, “to be on the safe side.”

“It takes a couple more minutes, but it’s something to consider in order to prevent wound leakage due to pressure on the eyeball when posturing in a face-down position. The sutures will spontaneously reabsorb in a few weeks,” he said.

Value of 20-gauge persists

According to Susanne Binder, MD, chair of ophthalmology at the Rudolf Foundation Clinic in Vienna, the sutureless approach is better in relatively simple cases, such as macular pucker and macular hole, but there is still scope for the 20-gauge approach in more complex surgery.

Susanne Binder

“I perform 23-gauge surgery in 60% to 70% of the cases and 20-gauge surgery in 30% to 40% of the cases. I use 25-gauge only for anterior segment vitrectomy,” she said.

“In more complex cases, where I know I need silicone, I do 20-gauge surgery because I believe that, with the use of silicone, sclerotomies need to be sutured. When the silicone escapes subconjunctivally, which can happen in sutureless cases, it packs under the conjunctiva and Tenon’s capsule, causing irritation and foreign body sensation. More importantly, the 20-gauge system provides a wider armamentarium of instruments to deal with complex cases, and a sutured wound is safer. I don’t want my patients to carry unnecessary risks,” she said.

In two prospective studies, Dr. Binder and colleagues compared 25-, 23- and 20-gauge surgery in relation to safety, surgical time and patient comfort.

“We found, as many other authors did, that there are wound-related complications in sutureless surgery. Surgical time was shorter because no sutures were applied, but what was gained with not having to suture the wound was lost in the longer time for vitreous removal. Now, with the new instruments, cutting rate is faster, but often the shorter surgical time is due to the fact that you remove a lesser quantity of vitreous in [microincision vitrectomy],” Dr. Binder said.

According to Dr. Binder, patient comfort is significantly better with microincision vitrectomy procedures. As with microincision cataract surgery, patients are happier during the first week because there is no pain. However, neither time nor comfort during the first postoperative days should be priority criteria when a patient’s safety is at stake, she noted.

There are eight vitreoretinal surgeons in Dr. Binder’s practice dealing with a high volume of vitreoretinal procedures, approximately seven to eight per day. The Alcon Accurus and Constellation as well as the Oertli OS3 systems are used.

Advantages of a 27-gauge approach

According to Yusuke Oshima, MD, associate professor at Osaka University Graduate School of Medicine, a truly self-sealing wound for uncomplicated yet effective microincision vitrectomy surgery can be obtained with an even smaller, 27-gauge approach.

“We have been using 27-gauge needles for many years in post-vitrectomy treatments, such as performing transconjunctival fluid-fluid or fluid-air exchange. No wound-related complications have been reported. Therefore, 27-gauge may be the maximum size for achieving perfect and easy self-sealing wounds,” he said.

A unique set of 27-gauge instruments, developed in collaboration with DORC, was used in a pilot study. A total of 31 eyes of 31 patients with a variety of retinal diseases, including epiretinal membrane proliferation, idiopathic macular hole, diabetic macular edema and nonclearing vitreous opacity, were successfully treated.

“Outside the study, I have personally treated about 100 patients with not only macular diseases but more challenging conditions like rhegmatogenous retinal detachment and diabetic traction retinal detachment,” Dr. Oshima said.

“Complex techniques for creating a self-sealing wound, such as angled insertion, are no longer needed. Even the trocar-cannula system, although available, is not required in simple cases. You simply go through the conjunctiva and sclera with a 27-gauge needle, inserting it vertically. The incision seals completely after the procedure. I have had no case of hypotony, wound leakage or vitreous incarceration,” he said.

Powerful light sources, such as xenon and mercury vapor light, have enabled the use of 27-gauge optic fiber for endoillumination. According to Dr. Oshima, many stiffer 27-gauge instruments have also been developed for intraocular manipulations.

The only disadvantage is cutting efficiency, he said. The 27-gauge vitreous cutter has about 80% of the efficiency of 25-gauge cutters. However, even with this limited performance, he was able to carry out vitrectomy effectively and accurately. The average operating time was 30 minutes.

“Some surgeons might find that the instruments are fragile and not easy to handle. I don’t think this should be a problem in expert hands. With the wide-angle viewing system, you don’t need to move the eye a lot, and you only need small, controlled movements with your instruments,” he said.

With a few refinements, the technique might gain popularity in the near future, Dr. Oshima said.

“Highly efficient 27-gauge cutters may not be just a dream. New-generation machines with a dual-actuation technology allow for ultra-high cutting rate with duty cycle control. If this technology was applied to 27-gauge, we would be able to achieve a much higher performance in the future,” Dr. Oshima said.

Present and future of vitrectomy machines

“The advent of small-gauge instrumentation, which started with basic features and now encompasses almost the entire range of features that are available with larger-gauge systems, has definitely made a lot of difference both in terms of meeting surgeons’ requirements and patient expectations, without compromising surgical results,” said Pramod S. Bhende, MD, senior consultant at the Medical Research Foundation’s Sankara Nethralaya eye hospital in Chennai, India.

Dr. Bhende uses Alcon and Bausch + Lomb systems equally often and finds both equally comfortable.

“The modular system in Bausch + Lomb, where modules can be added or replaced without disturbing the entire system, is definitely an advantage. I had the chance to see the Stellaris prototype last year. I hope it proves to be a sturdy machine with all the sophistication that is promised, including the 5,000-cpm pneumatic cutter, dual illumination with xenon and mercury vapor sources, viscous fluid injectors, venturi pump, cordless foot pedal with possibility of remote software updates and preventive maintenance,” he said.

Dr. Bhende works in a setting that involves multiple users of a single machine and a huge variety of surgical cases. For him, his colleagues and his maintenance staff, versatility and durability are essential features.

Manish Nagpal, MS, DO, FRCS, senior consultant at the Retina Foundation in Ahmedabad, India, is a longtime Alcon user and is satisfied with the performance of Alcon instruments.

“Currently we use the new Alcon Constellation system and the Accurus in some cases. The Constellation has been built for small-gauge specifically and has faster fluidics and more accurate infusion pressure. The vitreous cutter works at a speed of 5,000 cpm. It is extremely safe and allows us to go very close to the retina,” he said.

The issues of cost and availability remain crucial for the popularization of small-gauge surgery in the future, according to Dr. Bhende.

“Though the basic vitrectomy packs of Alcon and Bausch + Lomb [microincision vitrectomy] systems have comparable prices, the overall cost is still high compared to 20-gauge instruments,” he said.

“In a real-world situation, even in a developed country, cost is a crucial factor for the patient who needs to pay for the surgery, for the surgeon or the institute that buys the equipment, and for the insurance companies or governments who reimburse the costs,” he said. “Special instruments need to be available more easily without the need to wait for long periods of time for procurement.” – by Michela Cimberle

Is the risk of endophthalmitis too high in sutureless transconjunctival vitrectomy?

References:

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• Pramod S. Bhende, MD, can be reached at Department of Vitreoretinal Surgery, Sankara Nethralaya, Medical Research Foundation, 18 College Road, Nungambakkam, Chennai 600006, Tamil Nadu, India; +91-44-28271616; e-mail: pramod1999@yahoo.com.
• Susanne Binder, MD, can be reached at Department of Ophthalmology, Ludwig Boltzmann Institute for Retinology and Biomicroscopic Laser Surgery, Rudolph Foundation Clinic, Juchgasse 25, 1030 Vienna, Austria; +43-17-11654607; fax: +43-17-11654609; e-mail: susanne.binder@wienkav.at.
• Paolo Lanzetta, MD, can be reached at the University of Udine, Department of Ophthalmology, Piazzale S. Maria della Misericordia; 33100 Udine, Italy; +39-04-32559905; fax: +39-04-32559904; e-mail: paolo.lanzetta@uniud.it.
• Jong Jian Lee, MD, FRCS, can be reached at Raffles Hospital, 585 N. Bridge Road, Singapore 188770; e-mail: jongjian@hotmail.com.
• Manish Nagpal, MS, DO, FRCS, can be reached at the Retina Foundation, Near Shahibaug Underbridge, Rajbhavan Road, Ahmedabad 380004, Gujarat, India; +91-79-22865537; fax: +91-79-22866381; e-mail: drmanishnagpal@yahoo.com.
• Yusuke Oshima, MD, PhD, can be reached at Department of Ophthalmology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka Suita, Osaka 565-0871, Japan; +81-66-8793456; fax: +81-66-8793458; e-mail: oshima@ophthal.med.osaka-u.ac.jp. Dr. Oshima has no financial interests directly related to the products mentioned in the article but has received lecture fees and travel support from DORC.