How to surgically manage iatrogenic zonular disinsertion

An approach is described for completing cortex removal and IOL implantation after intraoperative 180° zonular dialysis.

Take-home: An approach is described for completing cortex removal and IOL implantation after intraoperative 180° zonular dialysis.

Reviewed by Iqbal (“Ike”) Ahmed, MD

Toronto-When an overly aggressive attempt to remove tenacious cortex results in iatrogenic zonular dialysis, the first priority for the cataract surgeon is to maintain capsule integrity and avoid vitreous prolapse. Removal of residual cortex is also important for the final outcome.

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Options for management might include cautious endocapsular phacoemulsification, conversion to extracapsular surgery, capsular retractors, implantation of a capsular tension ring (CTR), and use of a sutured capsular tension device, reported Iqbal (“Ike”) Ahmed, MD. The decision, however, is best made through careful assessment of the situation once the eye is stabilized.

Dr. Ahmed, assistant professor of ophthalmology and vision sciences, University of Toronto, Ontario, Canada, presented his approach to managing this “disinsertion dilemma” in a case involving a 180° zonular dialysis.

The patient did not have pseudoexfoliation or other risk factors for zonular weakness, and the surgery was uneventful until cortex removal. As the operating surgeon persisted in trying to remove residual cortex, the capsule was aspirated into the instrument tip, resulting in 180° of nasal zonular dialysis with retained cortex in the capsular bag. Fortunately, the capsular bag remained intact, Dr. Ahmed said.

Injecting OVD

After stopping the procedure and while keeping the I/A tip in the eye, a cohesive ophthalmic viscosurgical device (OVD) was instilled to reform the anterior chamber and stabilize the eye.

Dr. Ahmed offered several tips for completing this initial step.

“It is important to keep the I/A instrument in place because if the capsule has been aspirated into the tip, removing the hand piece from the eye could bring the entire capsular bag too,” Dr. Ahmed said.

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The injected OVD can displace any aspirated capsule from the tip, but before OVD is injected, infusion should be stopped or the OVD will come back out from the incision site. At the same time, surgeons should not overfill the eye–as that also will cause OVD to leak out of the incision, and vitreous prolapse may follow.

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Once the I/A tip is freed of material and the chamber stabilized, examination showed the residual cortex present in the superior area of the capsular bag, well away from the site of the zonular dialysis. Considering that use of an automated technique for completing cortex removal could create an unstable situation, Dr. Ahmed chose a manual approach to cortex aspiration, using a 27-gauge hockey stick cannula to irrigate and aspirate the residual cortex.

“It is important to add a few boluses of irrigation that will not only help with cortex removal but will also keep OVD away from the cannula,” he said.

Comfort level for CTR

After completing cortex removal, Dr. Ahmed said he was comfortable placing a CTR to stabilize the capsular bag in this case, taking into account the location of the zonular dialysis, its extent, and anticipating that it was stationary, i.e., non-progressive.

“My limit for using a standard CTR is up to six clock hours of localized zonulysis, assuming the remaining zonules are in good shape,” Dr. Ahmed explained. “In that setting, the CTR is quite effective in distributing forces around the entire capsular circumference.

“In addition, the dialysis in this eye was 180° away from the incision, which enabled injection of the CTR into the area of weakness,” he added. “That would have been more difficult if the dialysis was located temporally.”

Dr. Ahmed removed cortex first rather than starting with placement of the CTR-as the latter sequence could result in trapping cortex behind the ring.

Dr. Ahmed then implanted a one-piece IOL, which he favored because its insertion is atraumatic relative to a three-piece implant. OVD was removed manually due to concern over the possibility of bringing vitreous forward using the I/A hand piece in an automated technique.

“The outcome seemed favorable, although I felt if the lens decentered, I could still go back in the first few months postoperatively to suture the CTR to the sclera and avoid a more extensive secondary procedure in the OR,” said Dr. Ahmed. “Fortunately, the IOL has remained well-centered.”

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Ike Ahmed, MD

e. ike.ahmed@utoronto.ca

This article is based on a presentation given by Dr. Ahmed at the 2015 American Academy of Ophthalmology meeting.

Dr. Ahmed is a consultant to Abbott Medical Optics, Alcon, and Bausch + Lomb.