Fish-tail technique for capsular tension ring insertion

Fish-tail technique for capsular tension ring insertion

TECHNIQUE Fish-tail technique for capsular tension ring insertion Romesh I. Angunawela, MRCOphth, Brian Little, FRCOphth We describe a simple, effec...

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TECHNIQUE

Fish-tail technique for capsular tension ring insertion Romesh I. Angunawela, MRCOphth, Brian Little, FRCOphth

We describe a simple, effective technique for the insertion of a capsular tension ring (CTR) in cases of zonular instability. The fish-tail technique minimizes tangential and shearing forces on the capsule and limits further zonular damage because the CTR is not dialed into position. Instead, the CTR is folded until the trailing loops overlap, forming a fish-like configuration. The apex or mouth of the fish is inserted through the incision into the capsular bag, and the remaining arms of the CTR are then placed in the bag. The technique requires no further manipulation or rotation of the CTR. J Cataract Refract Surg 2007; 33:767–769 Q 2007 ASCRS and ESCRS

Zonular dehiscence can occur during nucleus removal, aspiration of soft lens matter, or intraocular lens (IOL) insertion. Eyes with pseudoexfoliation syndrome are particularly at risk for zonular weakness.2 The safe and effective management of intraoperative zonular dehiscence has been improved by the development of the capsular tension ring (CTR), first described by Hara et al.1 Introduction of a CTR maintains the circular contour of the capsular bag and subsequently supports the sector of missing zonules and assists in evenly distributing stress on the remaining zonules. This helps prevent lens decentration and subluxation and may reduce the risk for vitreous prolapse.3 Insertion of a CTR is achieved using an injector or a freehand bimanual technique. The traditional method involves introducing the leading end under the rim of the capsulorhexis and feeding the rest of the ring by pushing it from behind, which compresses it and dials it into the bag. The trailing end is then dropped beneath the edge of the subincisional capsulorhexis and released from the forceps or right-angled hook by which it is being held. The ease of insertion

Accepted for publication December 19, 2006. From the Department of Ophthalmology, Royal Free Hospital, London, United Kingdom. Neither author has a financial or proprietary interest in any material or method mentioned. Corresponding author: Mr. Brian Little, Consultant Ophthalmologist, Royal Free Hospital, London, NW3 2QG, United Kingdom. E-mail: brianli[email protected] Q 2007 ASCRS and ESCRS Published by Elsevier Inc.

depends on the hardness of the cataract and the surgical stage at which it is attempted. It can be particularly challenging during the later stages when the capsular bag is empty and flaccid, with little zonular support, or contains an IOL. In these situations, any dialing technique has a high chance of snagging the CTR on the equatorial bag or the IOL, causing significant additional shearing and tractional stress on the zonules as well as a greater risk for tearing the capsule (Figure 1). We describe a simple, safe, and effective method for introducing a CTR under these circumstances. It requires no dialing and is therefore significantly less stressful on the already compromised or torn zonules. We have named this the fish-tail technique because of the resemblance of the over-compressed CTR to a fish tail. Although this technique can theoretically be used at any stage of surgery, early insertion of a CTR in the presence of a hard cataract is difficult with any technique.

SURGICAL TECHNIQUE Regardless of the technique used to insert the CTR, the capsular bag and anterior chamber should be fully expanded with an ophthalmic viscosurgical device, preferably cohesive, to ensure that the capsule is under tension and free of folds. The C-shaped open ring is grasped symmetrically on both sides with 2 pairs of forceps about two-thirds of the way down. The ring is then tightly compressed by pushing the forceps toward each other to deform the ring into a fish shape, with the ends overlapping to form the tail. The ring is flexed sufficiently for the apex (‘‘head’’ of the fish) to pass with minimal 0886-3350/07/$dsee front matter doi:10.1016/j.jcrs.2006.12.036

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TECHNIQUE: FISH-TAIL TECHNIQUE FOR CTR INSERTION

Figure 1. The CTR is introduced using an injector. Shearing stress lines are evident on the posterior capsule.

Figure 3. The apex of the CTR is placed in the capsular bag, opposite the site of the main incision.

resistance through an unenlarged incision, which in our case is 2.8 mm (Figure 2). The rings used by us (John Weiss and AMO) withstand this degree of flexion and remain within their elastic limit without crimping. Once inside the eye, the ring opens, largely under its own recoil (with a little encouragement from the feeding forceps), and the apex has to be located under the distal edge of the capsulorhexis, diametrically opposite the main incision (Figure 3). It is easier to insert the under-riding arm first; if the over-riding arm is inserted first, the surgeon will be pressing down on it from above. One forceps is used to flex and deliver the leading end of the ring under

the edge of the capsule; the trailing end is held with the other forceps (Figure 4). The trailing end of the ring is then fed through the incision and flexed so it lies central to the subincisional edge of the capsulorhexis. This can be achieved using forceps, although a Sinskey hook through the eyelet is our preference because it causes less incisional gape and distortion and allows easier directional control for flexion of the ring (Figure 5). The flexion is then relaxed, which allows the ring to expand and be delivered under the capsulorhexis. The Sinskey hook may be awkward to release from the eyelet at this stage. This is facilitated by the use of a cyclodialysis spatula through the side port (Figure 6)

Figure 2. The apex of the flexed CTR passes with ease through a 2.8 mm incision.

Figure 4. One forceps is used to flex and deliver the leading end of the CTR under the edge of the capsule, while the other holds the trailing end.

J CATARACT REFRACT SURG - VOL 33, MAY 2007

TECHNIQUE: FISH-TAIL TECHNIQUE FOR CTR INSERTION

Figure 5. The trailing limb of the CTR is placed in the bag using a Sinskey hook through the eyelet.

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Figure 7. The CTR is disengaged from the Sinskey hook and delivered into the capsular bag.

generated by the conventional method of dialing the ring into the bag using linear feed from an injector or forceps. This is particularly relevant in vulnerable cases in which there is extensive or diffuse zonular loss. We prefer this technique in all conditions and highly recommend its use. The technique relies on compression and elastic recoil of the ring; minimal, if any, dialing is required. This is possible because of the considerable elastic limits of poly(methyl methacrylate). We find the supplementary use of capsular hooks an invaluable adjunct in stabilizing the bag and providing added protection for the remaining zonules. REFERENCES Figure 6. A cyclodialysis spatula is introduced through the side port to disengage the Sinskey hook from the CTR.

to push the ring down and disengage it (Figure 7). Alternatively, the eyelet can be readily disengaged by lifting it up against the undersurface of the adjacent iris hook that is being used to stabilize the capsule.

1. Hara T, Hara T, Yamada Y. ‘‘Equator ring’’ for maintenance of the completely circular contour of the capsular bag equator after cataract removal. Ophthalmic Surg 1991; 22:358–359 2. Schlo¨tzer-Schrehardt U, Naumann GOH. A histopathologic study of zonular instability in pseudoexfoliation syndrome. Am J Ophthalmol 1994; 118:730–743 3. Gimbel HV, Sun R. Clinical applications of capsular tension rings in cataract surgery. Ophthalmic Surg Lasers 2002; 33:44–53

DISCUSSION The fish-tail technique is a straightforward, safe, and effective method for inserting a CTR. It minimizes the radial and circumferential zonular stresses

J CATARACT REFRACT SURG - VOL 33, MAY 2007

First author: Romesh I. Angunawela, MRCOphth