Microincisional vitrectomy surgery targets macular disease

November 1, 2011

Microincisional vitrectomy surgery using 23- and 25+-gauge instrumentation enhances the surgical management of complex macular pathologies.

Boston-Microincisional vitrectomy surgery (MIVS) using 23- and 25+-gauge instrumentation enhances the surgical management of complex macular pathologies. Most patients in a retrospective study achieved a 2-line or greater increase in visual acuity with very few surgical complications, said Timothy G. Murray, MD, MBA, at the annual meeting of the American Society of Retina Specialists.

"Macular pathology continues to evolve as a surgical target," said Dr. Murray, professor of ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami.

"Vitrectomy performed with the goal of stabilizing the retinal anatomy is associated with improvements in the visual function," he said. "Advances in surgical instrumentation have improved the surgical outcomes, limited patient concerns, and extended the indications for surgery."

MIVS is associated with a number of advantages, such as improved trocar entry systems, high-speed vitrectomy cutting, improved aspiration and fluidics, small-gauge high-luminance endoillumination, and wide-field vitreoretinal surgical viewing, according to Dr. Murray. Other fairly recent advances are intravitreal anti-VEGF agents and intravitreal steroids.

Clinical study

Dr. Murray conducted a retrospective review of 327 eyes of 299 prospective patients with a retinal pathology who had undergone 23/25+-gauge MIVS surgery. Intravitreal triamcinolone acetonide was injected at the end of each surgery. The factors of interest during the study were the intraoperative events and the anatomic and visual acuity outcomes. One surgeon performed all procedures at the Bascom Palmer Eye Institute.

The mean patient age was 69 years (range, 28 to 93), and 57% of patients were women. The vitreoretinal pathologies were intraocular tumors in 167 eyes (51%), epiretinal membranes with vitreomacular traction in 85 (26%) eyes, and traction retinal detachments with proliferative diabetic retinopathy in 75 (23%) eyes. The patients were followed for a median of 12.2 months (range, 3 to 37) postoperatively.

The following procedures were performed: oblique 23/25+-gauge trocar placement, with confirmation of intravitreal infusion; three-port MIVS pars plana vitrectomy with injection of 4 mg/0.1 ml intravitreal triamcinolone acetonide; and membrane peeling was performed as needed. Dr. Murray said that intravitreal triamcinolone was administered to control intraretinal edema after surgery; use of triamcinolone acetonide in this context is an off-label use of the drug and is controversial, he noted.

The only surgical complication that developed was hypotony defined as IOP of 5 mm Hg or less in seven cases treated with a 23-gauge procedure and in one case treated with the 25+-gauge procedure. Endophthalmitis or retinal detachments did not develop. One patient underwent a secondary glaucoma surgery.

More than three-quarters of the study eyes (249 of 327 eyes, 76%) gained two lines or more of visual acuity. Compared with the baseline logarithm of the minimum angle of resolution (logMAR) visual acuity of 0.983, the logMAR visual acuity levels at 3 and 6 months, respectively, were 0.810 and 0.675, Dr. Murray said.