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Intraocular cowhitch method, improved needle provide good fixation for dislocated IOL

Issue: July 15, 2001

ByTsutomu Kawasaki, MD

ByTsukasa Hanemoto, MD

ByHidenao Ideta, MD

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KUMAMOTO, Japan — An intraocular cowhitch method with an improved needle for suturing dislocated IOLs enables safer fixation without extraction.

Suturing without extraction

The traditional approach to repositioning a posteriorly dislocated IOL is to extract it and suture on the ciliary sulcus. But to reduce postoperative astigmatism and complications, it is best to fixate it without extraction of the IOL. We developed a method of suturing a posteriorly dislocated IOL to the ciliary sulcus using an intraocular cowhitch knot without IOL extraction (figure l).

Improved needle

To make an intraocular cowhitch knot, a straight needle with a looped thread that fits a 27-gauge guiding needle is ideal. Using a larger needle, like a 25-gauge, may trigger vitreous incarceration and postoperative retinal detachment. To our knowledge, there is currently no ideal needle on the market. Despite the technological difficulty, MANI Inc. managed to make two holes in the needle by laser beam and to bind the end of the thread to make a loop. Our improved needle is the MANI1486L (Ideta Eye Hospital, Kumamoto City, Japan). It is a straight tapered spatula needle with looped 10-0 polypropylene. The caliber of this needle is 0.14 mm, and the length is 16 mm (figure 2a, 2b). This needle is also useful for “ab interno methods” in suturing IOL for aphakia losing zonular support because it can be bent to meet the surgeon’s needs.

Cowhitch method

Recently, we used our needle to suture a posteriorly dislocated IOL to the ciliary sulcus using an intraocular cowhitch knot without IOL extraction. This technique is applicable for a dislocated IOL that can be pulled out onto the iris by manipulating it through two corneal side ports made by paracentesis (figure 3). If the IOL is totally luxated in the vitreous cavity, a three-port vitrectomy must be done.

Surgical technique

Two corneal incisions are made by paracentesis at the 3 and 9 o’clock positions, and the posteriorly dislocated IOL is pulled out onto the iris with a lens hook. A needle with looped 10-0 polypropylene (MANI1486L) is introduced into the anterior chamber through one side port and is passed underneath one haptic of the IOL guided by a bent 27-gauge needle from the opposite side port (figure 4). After extracting the needle from the opposite side port (figure 5), the end of the loop is pulled out with a push-and-pull hook passing over the haptic (figure 6).

By passing the needle through the loop, a cowhitch knot is made outside the chamber. Pulling the needle brings the knot back into the anterior chamber. The same procedure is done for the other loop (figure 7).

To suture onto the sulcus, the needle with the knot is reintroduced into the anterior chamber guided by a bent 27-gauge needle that is passed through the ciliary sulcus 1.5 mm from the limbus of the opposite side, where two 2-mm-long lamellar scleral incisions have already been made radial to the limbus (figures 8, 9). After repeating the procedure for the other haptic, pulling up the two sutures drops the IOL back into the posterior chamber. The IOL naturally rotates (figure 10).

The needle is passed through the two lamellar scleral incisions in the fashion of a mattress suture. The sutures are tied and buried in the scleral incisions (figure 11). In six cases treated with this technique, the IOL was fixated stably and remained well-positioned for more than 1 year after surgery (figure 12). No trauma to the iris or other complications occurred intraoperatively or postoperatively.

Advantages of intraocular cowhitch

The intraocular cowhitch knot technique provides a better grip of the IOL haptic and better stability than does a single knot. Damage to the IOL haptics was minimal. Intraocular cowhitch knots provide less opportunity for vitreous incarceration and postoperative vitreoretinal complications. With our technique, intraocular inflammation is minimal because the entire procedure takes place under a closed system. This technique enables secure fixation of a dislocated IOL to the ciliary sulcus.

For your information:

• Tsukasa Hanemoto, MD, can be reached at Ideta Eye Hospital, 1-35 Gofukumachi, Kumamoto City, 860-0035, Japan; (81) 96-325-5222; fax: (81) 96-311-5512; e-mail: hanemoto@tb3.so-net.ne.jp; Web site: http://www.iijnet.or.jp/ideta/.
• MANI Inc., can be reached at 743 Nakaakutsu Takanezawa-machi, Tochigi-ken, 329-1234, Japan; (81) 028-675-2411; fax: (81) 028-675-0139; e-mail: obata@ms.mani.co.jp; Web site: http://www.mani.co.jp.

Reference:

• Hanemoto T, Ideta H, Kawasaki T. Dislocated intraocular lens fixation using intraocular cowhitch knot. Am J Ophthalmol. 2001;131:268-269.