Modified capsule expander may help in cases of subluxation and phacodonesis

For patients with severe zonular weakness, a T-shaped capsule stabilization hook may be used to reposition and permanently fixate the lens capsule.

A T-shaped capsule stabilization hook, or modified capsule expander, may aid lens implantation in patients with significant zonular weaknesses.

“[The] modified capsule expander (M-CE) suspends the lens capsule IOL complexes more safely and securely compared with ordinarily used capsular stabilization devices in cases with severe lens subluxation and phacodonesis,” Shigeo Yaguchi, MD, corresponding author of the study and inventor of the M-CE (Handaya), said in an email interview with Ocular Surgery News.

The M-CE is made of 5-0 polypropylene, has a 150-µm diameter and is attached to a curved needle, with its contact portion bent at 1.25 mm. The end of the contact segment bifurcates in a T configuration to form a 3.75-mm footpad on which the capsular bag may be suspended.

“Secured stabilization results from the shape and fixation of the M-CE. The M-CE has a T-shaped configuration that simultaneously expands the capsule equator and the edge of a continuous curvilinear capsulorrhexis,” Dr. Yaguchi said.

Atraumatic insertion of the expander, which is introduced from a stab incision and implanted without a dialing technique, also contributes to the safety of fixation. The incision is made opposite the scleral flap, and the M-CE is attached to a needle and guided through the ciliary sulcus.

Dr. Yaguchi and colleagues previously reported on a similar T-shaped capsule hook (Handaya) used to suspend and stabilize the capsule and facilitate safe phacoemulsification. Shaped like an iris retractor, the original capsule expander was fixated to the corneal limbus by adjusting a silicone rubber ring, resulting in temporary fixation. The modified hook, particularly its curved needle, was based on clinical experience with this prior design.

Surgical tips

The study authors recommended inserting the device into the capsular bag immediately prior to IOL implantation. When introducing the M-CE to the anterior chamber, surgeons should be careful not to tear the continuous curvilinear capsulorrhexis with the hook, Dr. Yaguchi said. Moreover, he suggested flattening the tip of the externalized M-CE with a cautery device upon fixation and then burying it under the scleral flap in order to prevent postoperative exposure.

“The M-CE can provide postoperative capsular support, which is the most ideal location for an IOL, providing optimal biocompatibility, centration and optics,” Dr. Yaguchi said.

Four eyes were implanted with the M-CE and then followed up for a mean of 12.3 ± 3 months. IOLs remained well centered and stable throughout this period, and corrected distance visual acuity improved to at least 20/20 in all patients postop. Mean endothelial cell loss was 6.7% ± 4.2%.

Future developments

The study authors encouraged further development to improve the simplicity and security of fixation. For instance, to prevent rotation they are designing an M-CE with a plane or fuzz at the part that penetrates the sclera.

The study authors alleviated slippage of the M-CE from the sclera by using a needle holder and cautery device. To make suture fixation more secure, M-CEs with holes or notches will likely be designed, they said. They also suggested modified expanders with balls on the tips of the T-shaped ends to prevent damage to the lens capsule, which may become torn during manipulation.

Dr. Yaguchi said that his research team is planning to use the device for subluxated IOL capsule complexes after capsular tension ring insertion and to follow up on all M-CE patients long-term.

“The indication for use of the M-CE is not only for lens subluxation and phacodonesis but also for severe in-the-bag IOL dislocation. We will soon present M-CE implantation for cases of IOL dislocation,” he said. – by Michelle Pagnani

References:

• Nishimura E, Yaguchi S, Nishihara H, et al. Capsular stabilization device to preserve lens capsule integrity during phacoemulsification with a weak zonule. J Cataract Refract Surg. 2006;32(3): 392-395.
• Yaguchi S, Yaguchi S, Asano Y, et al. Repositioning and scleral fixation of subluxated lenses using a T-shaped capsule stabilization hook. J Cataract Refract Surg. 2011;37(8):1386-1393.

• Shigeo Yaguchi, MD, can be reached at the School of Medicine, University of Showa, Fujigaoka Hospital 1-30, Fujigaoka, Aoba-ku, Yokohama 227-8501 Japan; email: yaguchis@fa.mbn.or.jp.
• Disclosure: Dr. Yaguchi is the inventor of the modified capsule expander and received financial support from Handaya.

This article presents an interesting addition to our armamentarium of devices to manage subluxated cataracts. The modified capsule expander (M-CE) joins devices such as the Cionni ring, Ahmed segment and Assia capsular anchor, increasing our options to support lenticular capsules with significant zonular weakness or absence. Advantages of this device include the ability to insert it through a much smaller incision and its small size once inside the eye, despite a broad area of capsular support that seems as large as that of other segmental devices. Time will tell which device achieves the greatest popularity, but if the M-CE works as well as the article suggests, it should be used often by cataract surgeons.

– Steve A. Arshinoff, MD, FRCSC
OSN Cataract Surgery Board Member
Disclosure: Dr. Arshinoff is a consultant for Alcon and Arctic Dx.