Two knotting techniques can be used to relocate single-piece foldable IOLs

A closed-loop cow hitch knot or an open-loop clove hitch or reef knot can be used to secure the haptic to the sclera.

Issue: May 25, 2011

BySuven Bhattacharjee, MS, DO, DNB

Thomas John

A subluxated or unstable posterior chamber IOL needs to be repositioned and fixated to the sclera. This can often be a surgical challenge, and various surgical approaches have been described in the literature. Some of these techniques require a large limbal wound, with exteriorizing the IOL before it is repositioned and stabilized to the sclera. However, if for the most part such a procedure can be performed through small entry wounds, without the need for a larger limbal wound and without exteriorizing the entire IOL or exchanging the IOL, this will benefit the patient with less or no induced astigmatism and less chance of potential intraocular infection. It is important to secure the lens in a stable position in the posterior chamber, with the IOL haptics in the ciliary sulcus but away from the iris to prevent iris chafing, thus avoiding pigment dispersion, uveitis and secondary glaucoma.

In this column, Dr. Bhattacharjee describes a useful surgical technique of repositioning a single-piece foldable IOL. This technique takes advantage of the flexibility of a foldable IOL haptic, which can be securely anchored to the sclera using a 9-0 Prolene suture. He provides two different types of knotting techniques — a closed-loop cow hitch knot or an open-loop clove hitch or reef knot — that the surgeon can choose from while performing this technique.

Thomas John, MD
OSN Surgical Maneuvers Editor

Paracenteses are made at the 10 o’clock and 2 o’clock positions (Figure 1). The anterior chamber is filled with viscoelastic, and the IOL is brought into the anterior chamber. Anterior vitrectomy is performed, and capsular remnants are removed. The conjunctiva is opened at the 3 o’clock and 9 o’clock positions. Scleral flaps or partial-thickness scleral grooves 3 mm × 1 mm are prepared with a crescent knife 2.5 mm parallel to the limbus at these sites. Effectively, these grooves extend until they are 1.5 mm from the limbus. Thus, the haptics can be fixated at the posterior part of the ciliary sulcus and away from the iris. A straight needle with a 9-0 Prolene suture is passed transsclerally, 1.5 mm from the limbus, through the 3 o’clock scleral flap bed or groove. This is docked into a cannula and brought out through the 10 o’clock paracentesis. The procedure can now follow one of two alternate courses, depending on the surgeon’s choice of knot to be used to secure the haptics of the foldable IOL.

Closed-loop cow hitch knot

The straight needle is now passed back through the same 10 o’clock paracentesis to retrace its path into the eye. It is docked into a 26-gauge needle that has been passed through the 3 o’clock scleral groove, 1 mm away from the original entry of the 9-0 Prolene suture (Figure 1). Thus, the 9-0 Prolene suture has passed transsclerally through the 3 o’clock scleral groove to exit through the 10 o’clock paracentesis, made a closed loop here and retraced its path to exit through the 3 o’clock scleral groove. A Hirschman hook is also used to deliver a haptic out of the 2 o’clock paracentesis (Figure 2). The Hirschman hook is passed through the same paracentesis to hook a limb of this suture and bring out the closed loop through this paracentesis wound (Figure 2). A cow hitch knot is prepared with this loop (Figure 3). The haptic is passed through the cow hitch knot, and the knot is tightened. The haptic is reposited as the transscleral Prolene sutures are pulled (Figure 4). The suture is tied with 3-2-1 throws, and the haptic is secured. The same procedure is repeated to anchor the other haptic at 9 o’clock.

Figure 1. A 9-0 Prolene suture passed transsclerally at 3 o’clock, brought out through 10 o’clock paracentesis and retraced back to create a loop.

Figure 2. Haptic and 9-0 Prolene loop exteriorized through 10 o’clock paracentesis. Closed loop of Prolene is used to tie a cow hitch knot on the haptic.

Images: Bhattacharjee S, John T

Figure 3. Steps of tying a cow hitch knot from a closed loop of suture.

Figure 4. Haptic reposited and transscleral suture tightened at 3 o’clock. Similarly, other haptic tied and reposited as transscleral suture at 9 o’clock is tightened.

Open-loop clove hitch or reef knot

The straight needle is passed back into the eye through the 10 o’clock paracentesis and brought out through the 2 o’clock paracentesis by docking into a cannula. A haptic is hooked with the Hirschman hook and delivered through the 2 o’clock paracentesis. The 9-0 Prolene suture is tied to the haptic with a clove hitch or a reef knot. Both knots have the advantage of not loosening. The straight needle is now passed back into the eye through the 2 o’clock paracentesis and docked into a 26-gauge needle and brought out through the 3 o’clock scleral groove 1 mm away from the entry point. The haptic is reposited, and Prolene suture ends are tied as above. The same procedure is used to secure the other haptic at 9 o’clock.

Surgical pearls

Scleral grooves are easier to construct, and the Prolene suture has less chance of eroding through.
A 9-0 Prolene suture has less chance of breaking compared with a 10-0 Prolene suture.
Transscleral needles are passed vertical to the scleral surface; otherwise they may injure the iris.
With a well-dilated pupil, passing the suture anterior to the IOL allows easier visibility and access. But with a small pupil, needle and suture passes have to be posterior to the IOL.
Because single-piece IOL haptics are made of compressible material, the knots cannot be slipped on the haptic. Hence, the position of the knots should be finalized before the haptics are reposited. Once the haptics are secured and there is no movement of the IOL, there is no iris chafing, pigment dispersion or glaucoma.

References:

Bhattacharjee S, Chakrabarti A, Ghosh A. Minimally invasive relocation of subluxated single piece AcrySof intraocular lens. Br J Ophthalmol. 2008;92(6):746.

Chang DF, Masket S, Miller KM, et al; ASCRS Cataract Clinical Committee. Complications of sulcus placement of single-piece acrylic intraocular lenses: recommendations for backup IOL implantation following posterior capsule rupture. J Cataract Refract Surg. 2009;35(8):1445-1458.

Thomas John, MD, is a clinical associate professor at Loyola University at Chicago and is in private practice in Oak Brook, Tinley Park and Oak Lawn, Ill. He can be reached at 708-429-2223; fax: 708-429-2226; email: tjcornea@gmail.com.

Suven Bhattacharjee, MS, DO, DNB, can be reached at suvenb@gmail.com.

Disclosures: No products or companies are mentioned that would require financial disclosure.