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Sutureless vitrectomy using 25-gauge instrumentation reduces surgical time and results in faster visual recovery relative to 20-gauge vitrectomy. The risk of wound leak, however, is increased after the sutureless procedure, and that may lead to other complications. James T. Handa, MD, discusses these and other issues relating to the technique.
Baltimore-Sutureless small-incision vitrectomy with 25-gauge instrumentation has several advantages relative to the standard approach using a 20-gauge system, but surgeons will face a learning curve in adopting this technique and possibly an increased risk of complications, said James T. Handa, MD, at the Current Concepts in Ophthalmology meeting here.
Dr. Handa discussed the pros and cons of sutureless vitrectomy based on a review of published literature, as well as considerations for case selection and the future of the procedure with the arrival of new 23-gauge systems.
Reduced surgical time is one advantage of 25-gauge vitrectomy because it eliminates nonessential steps, thereby saving time in opening and closing, said Dr. Handa, associate chief, retina division, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore. Results of one study of patients with vitreous hemorrhage showed that mean operative time for 20-gauge vitrectomy was 66 minutes compared with 40 minutes for a 25-gauge technique, Dr. Handa said. As another advantage, the smaller-incision procedure is associated with faster visual recovery.
Although various studies show that procedure-related differences in anterior chamber inflammation and vision persist through 1 month after surgery, 20-gauge and 25-gauge vitrectomy are associated with similar visual acuity outcomes by 6 months.
"The inflammation resolves with time and suture-induced astigmatism also decreases, so that the final visual outcome in these cases is really determined by the disease that is being treated," Dr. Handa said.
The 25-gauge technique also has been purported to be associated with minimal pain. That benefit may be anticipated considering the smaller-incision technique causes less disruption to the eye, and it is supported by findings from one published study involving seven patients who underwent 25-gauge vitrectomy under topical anesthesia. The favorable pain ratings by patients in that report, however, may be more a measure of the efficacy of the anesthesia than a result of the surgery itself.
Therefore, in collaboration with his colleague Mark Walsh, MD, PhD, Dr. Handa has undertaken a randomized, masked study to compare pain after vitrectomy using 20-gauge versus 25-gauge equipment. The study aims to enroll 74 patients who will rate their pain on days 1 and 7 postoperatively using a validated pain assessment questionnaire.
Another feature of 25-gauge vitrectomy is that it allows the opportunity for "vitrectomy-less" vitreous surgery, a technique that in theory may reduce risk of postoperative cataract development. However, a longer-term study is needed to document the outcomes after that surgical approach, because it may be accompanied by some disadvantages.
"If a retinal detachment develops in an eye that has undergone vitrectomy-less vitrectomy, its repair may be more complicated," noted Dr. Handa.
An increased risk of wound leak is one concern accompanying small-incision vitrectomy because it can lead to hypotony, choroidal effusion, and endophthalmitis. Use of a scleral tunnel/beveled incision may minimize wound leak. In one study, that technique was associated with a 1% rate of wound leak compared with 5% using standard placement.
Other features of the small-incision vitrectomy, including the transconjunctival approach and use of a smaller volume of infusate, may also in theory increase the risk of postoperative endophthalmitis, Dr. Handa noted.
"However, the rate of that sight-threatening complication after sutureless vitrectomy remains to be characterized," he said.
Surgeons interested in using the 25-gauge instrumentation should expect a learning curve, although the transition is not terribly difficult. The smaller-caliber instruments used in the 25-gauge procedure are more flexible than their 20-gauge counterparts, so they are used with a slightly different technique. In addition, removing peripheral vitreous is more difficult using the 25-gauge instrumentation, and typically, less peripheral vitreous is removed. As a result, more vitreous skirt may remain, causing an issue in more complex cases in which it might increase the risk of retinal tears or detachment.