Cowhitch technique subluxated IOL without extraction

The technique offers a better grip of the IOL haptic and better stability than a single knot.

Issue: August 1, 2003

ByHidenao Ideta, MD

ByTsukasa Hanemoto, MD

ByTsutomu Kawasaki, MD

The traditional approach to repositioning an IOL subluxated into the vitreous cavity is to extract the IOL and suture it to the ciliary sulcus. However, IOL removal and reimplantation can cause corneal endothelial loss, and a large scleral incision to extract the IOL may produce astigmatism.

To maintain postop visual acuity, it is better to suture a luxated IOL to the ciliary sulcus without extracting the IOL.

We previously described an intraocular cowhitch in the anterior chamber for fixating dislocated IOLs. (See July 15, 2001, page 9.) In this report we describe a modified method of suturing an IOL luxated into the vitreous cavity to the ciliary sulcus using the intraocular cowhitch knot without IOL extraction.

The intravitreal cowhitch knot technique provides a better grip of the IOL haptic and better stability than a single knot. This technique enables secure fixation of a luxated IOL to the ciliary sulcus, reduces postop astigmatism and minimizes corneal endothelial cell loss.

Improved needle

To make an intravitreal cowhitch knot, a straight needle with a looped thread that fits a 27-gauge guiding needle is ideal. We previously described the needle in Ocular Surgery News. Using a larger needle, such as 25-gauge, may trigger vitreous incarceration and postop retinal detachment. Our improved needle is the Mani 1486L (Ideta Eye Hospital, Kumamoto City, Japan). It is a straight tapered needle, 0.14 mm caliber and 16 mm in length, with looped 10-0 polypropylene.

Recently we have been using this needle to suture posteriorly luxated IOLs to the ciliary sulcus using the intravitreal cowhitch knot without extracting the IOL. This technique can be used for an IOL totally luxated into the vitreous cavity that cannot be pulled out onto the iris by manipulation through corneal paracentesis side-ports.

Intravitreal cowhitch knot

First, we perform a three-port vitrectomy, including removal of peripheral vitreous and lens capsule remnants with scleral indentation.

For right-handed surgeons, a needle with looped 10-0 polypropylene is introduced through a sclerotomy at 10 o’clock, and only the needle is passed to the ciliary sulcus at 3 o’clock, 1.5 mm from the limbus, guided by a bent 27-gauge needle.

At this side, two lamellar scleral incisions 2 mm long radial to the limbus are made, following Horiguchi’s technique. A cowhitch knot is made outside the globe at the end of the 10-0 polypropylene, and the knot is grasped with straight intravitreal forceps. It is easier to make the knot using other forceps before grasping with the intravitreal forceps.

The knot is then introduced into the vitreous cavity using intravitreal forceps with the right hand and hooked around the haptics of the IOL. With the assistant pulling the needle, the IOL haptic is fixated to the ciliary sulcus.

To avoid slippage, the end of the haptic is grasped with intravitreal forceps while the suture is pulled. It is then sutured into the ciliary sulcus in mattress-suture fashion, passing the needle through the two previously made lamellar scleral incisions so that it is buried. The suture is temporarily tied until the opposite haptic is sutured before positioning the IOL at the center.

Opposite side

For the opposite side, the same fixation technique described in our previous article is used. The IOL haptic is brought up onto the iris with a lens hook or other vitreous instrument through the scleral port. Two corneal paracentesis side-port incisions are made at the limbus at the 3 and 9 o’clock positions. A needle with looped 10-0 polypropylene is introduced into the anterior chamber through the 3 o’clock side port and passed underneath the haptic of the IOL in the anterior chamber, guided by a bent 27-gauge needle from the 9 o’clock side port.

The needle is then extracted from the side port. While the end of the loop remains in the anterior chamber, it is pulled out of the side port by a push-and-pull hook passed over the haptic.

Outside the anterior chamber, the needle is passed through the loop, making a cowhitch knot. Simply pulling the needle brings the knot back into the anterior chamber. To suture this onto the ciliary sulcus, the needle with the knot is reintroduced into the anterior chamber through the 9 o’clock side port. The needle, guided by a bent 27-gauge needle that is passed through the opposite 3 o’clock side port over the IOL, is pulled out of the eye.

The needle is again passed through the same side port, going over the optic and haptic of the IOL, guided by a bent 27-gauge needle that is passed through a Horiguchi incision at the 9 o’clock position 1.5 mm from the limbus.

The haptic in the anterior chamber can be easily brought back to the posterior chamber by pulling the needle. After the IOL is centered, the sutures are permanently tied and buried in the scleral incisions.

When the IOL is luxated with the lens capsule, the capsular bag is removed from the IOL by vitreous cutter in the vitreous cavity.

A needle with looped 10-0 polypropylene is introduced through a sclerotomy at 10 o’clock. The needle is passed into the sulcus through two lameller scleral Horiguchi incisions at 3 o’clock, guided by a bent 27-gauge needle.	At the end of the loop, a cowhitch knot is made outside the globe and is grasped with straight intravitreal forceps.	The knot is introduced into the vitreous cavity and hooked around the haptics of the IOL using the intravitreal forceps.
With the assistant pulling the needle, the IOL haptic is fixated to the ciliary sulcus.	The suture is temporarily tied at the 3 o’clock Horiguchi incision.	The opposite IOL haptic is brought up onto the iris with a lens hook. Two corneal paracentesis incisions are made at the 3 and 9 o’clock positions.
After the needle is extracted from the 9 o’clock side port, the end of the loop in the anterior chamber is pulled out with a push-and-pull hook passed over the haptic.	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.	To prepare to suture the haptic to the sulcus, the needle with the knot is reintroduced into the anterior chamber through the 9 o’clock side port and passed out of the anterior chamber through the 3 o’clock side port, guided by a bent 27-gauge needle.
The needle is passed through the 3 o’clock side port and taken out through the Horiguchi incision at 9 o’clock in the ciliary sulcus at 1.5 mm from the limbus, guided by a 27-gauge needle. Pulling the suture easily brings the IOL haptics from the anterior chamber into the posterior chamber.	A 72-year-old woman with a subluxated IOL due to zonular dialysis. Vitreous is seen in the anterior chamber with hemorrhage, a good indication for the intravitreal cowhitch method.	The knot is made using external forceps before being grasped with the intravitreal forceps.
To avoid slippage, the end of the haptic is grasped with the intravitreal forceps while the suture is pulled.	A needle with looped 10-0 polypropylene is introduced into the anterior chamber through the 3 o’clock side port and passed underneath the haptic of the IOL, guided by a bent 27-gauge needle from the 9 o’clock side port.	The sutures are temporarily tied at Horiguchi’s incisions in mattress-suture fashion at 3 o’clock. By pulling both sutures at 3 and 9 o’clock, the IOL is brought to the center. The sutures are then permanently tied and buried.

For Your Information:

Tsukasa Hanemoto, MD, can be reached at Ideta Eye Hospital, 1-35 Gofukumachi, Kumamoto City, 860-0035, Japan; (81) 096-325-5222; fax: (81) 096-311-5512; e-mail: hanemoto@tb3.so-net.ne.jp; Web site: http://www.iijnet.or.jp/ideta/. Dr. Hanemoto has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.

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.

References:

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

Hanemoto T, Ideta H, Kawasaki T. Luxated intraocular lens fixation using intravitreal cowhitch (girth) knot. Ophthalmology. 2002; 109:1118-1122.