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Safety-basket suture used to manage malpositioned posterior chamber IOLs
The safety netting resembles a tic-tac-toe board with nine grids and is passed under the lens implant to stabilize it for suturing or removal.
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For the past several years, a surgeon has used a safety-basket suture for the surgical management of a late malpositioned posterior chamber IOL in the post-vitrectomy eye.
“The safety net is passed underneath the malpositioned IOL at the onset of the secondary surgery,” Samuel Masket, MD, said.
Typically, late malpositioned IOLs, due to progressive zonulysis, occur 8 to 10 years after initial cataract surgery. While there are a number of conditions that are responsible for this condition, most typically pseudoexfoliation, post-vitrectomy eyes are also at risk.
Through the years, a number of patients with malpositioned IOLs have been managed by Masket, in private practice in Century City, Calif., and a clinical professor of ophthalmology at the David Geffen School of Medicine, University of California, Los Angeles.
Samuel Masket
“In handling these cases, one of the concerns is that the lens implant will be so loose or be loosened by the surgical attempts to reposition it, such that the lens might unfortunately fall into the vitreous cavity,” Masket told Ocular Surgery News. “This is particularly true in the post-vitrectomy eye, where there is no supportive cushion. Should that lens become loose, it could easily fall to the back of the eye instantly and outside the grasp of the anterior segment surgeon, requiring retrieval by a posterior segment surgeon.”
Such a scenario greatly changes the course of surgery, as well as the prognosis and potential morbidity.
In response, Masket sought to develop a method that would preclude the total luxation of the lens implant into the posterior segment, ultimately adopting a kind of safety netting underneath the lens implant.
“The suture was born out of necessity,” he said.
To date, Masket’s practice has used the safety-basket suture on approximately 40 patients; 32 of his cases are reported in the Journal of Cataract and Refractive Surgery with co-author Nicole R. Fram, MD.
Technique
The surgical technique entails taking a 10-0 polypropylene suture on a straight, very sharp needle (STC-6, Ethicon) and making a small bend of approximately 15°, 4 mm to 5 mm from the sharp end of the needle.
“We do this with both ends of the needle, and we leave it double-armed,” Masket said.
The needle is then passed into the globe, through the pars plana, roughly 2 mm posterior to the limbus. On the opposing limbus, also 2 mm back, an angulated 27-gauge short disposable hypodermic needle is introduced through the pars plana as well.
“The two needles meet behind the IOL,” Masket said.
The polypropylene suture is then docked into the 27-gauge needle, and they are removed from the eye.
The second arm of the double-armed suture is passed in a similar fashion, parallel to the initial passage, separated by about 2 mm to 3 mm.
“This is also docked into a 27-gauge needle that has pierced pars plana from the opposite side of the globe,” Masket said.
Result
The result is a horizontal mattress suture underneath the IOL in the horizontal meridian. The process is then repeated in the vertical meridian.
“You end up with two horizontal mattress sutures. They form a tic-tac-toe pattern with nine grids,” Masket said. “However, care should be taken to avoid the 3 o’clock and 9 o’clock meridian because of the long posterior ciliary arteries.”
Once the safety net is passed under the lens implant, “the surgeon has the option of bringing the malpositioned lens into the anterior chamber for removal or it can be suture fixated to either the sclera or the iris,” Masket said. The basket sutures are then cut and removed from the eye. Peripheral retinal examination should be carried out on the table or in the very early postoperative period.
Masket said there is an increasing number of malpositioned lenses due to more vitrectomies being performed and patients living longer.
“This also seems to be a late complication of the current style of cataract surgery, where the lens is placed within the confines of a capsulorrhexis,” he said.
Masket looks forward to other surgeons adapting his technique and sharing their experience. – by Bob Kronemyer