Suture fixation technique for posterior chamber intraocular lenses

Abstract

 

We describe a modified method for scleral fixation of posterior chamber intraocular lenses (IOLs). A double-armed, 10-0 polypropylene (Prolene®) suture on a curved long needle is passed through a groove in the sclera and retrieved within the barrel of a bent 25-gauge needle through the opposite groove. Double transscleral passages enable 4-point fixation and provide better stability and centration. Knots are buried completely in the scleral groove. In a series of 10 cases, the IOLs were well centered, no sutures protruded from the scleral groove, and the vision in all eyes improved. In 1 case, a ciliary hemorrhage occurred during insertion of the 25-gauge needle, but the bleeding stopped after ocular pressure reform. This technique is easy to perform, improves centration and stability of the IOL, and avoids suture exposure.

Suture fixation of posterior chamber intraocular lenses (PC IOLs) is popular in cases in which capsule support is inadequate for IOL placement. A large study confirms the procedure is safe with a small risk for complications.¹ However, ultrasound biomicroscopic² and histopathologic³ studies report poor reliability with haptics placed in the sulcus. Tilting and decentering of the IOL can also occur.⁴ These findings indicate that the technique needs refinement. Based on our clinical observations, an optimal sulcus suture-fixated IOL should meet the following criteria: (1) The IOL should be stable without tilt. One-point fixation of each haptic is less favorable, while 2-point fixation prevents IOL tilt along the axis of the suture. (2) Good IOL centration depends on precise placement of the scleral-fixated suture. An ab interno approach generally cannot achieve as precise a penetrating site as an ab externo approach. (3) Suture knots should be buried; otherwise, they may erode the tissue, causing discomfort or inducing endophthalmitis in a worst-case scenario. We report a modified surgical technique that meets these criteria.

Surgical Technique

A conjunctival peritomy is created in the superior limbus. Anterior vitrectomy is performed if necessary. After vitrectomy, the anterior chamber and the retropupillary space are filled with an ophthalmic viscosurgical device (OVD). The OVD protects the endothelium, pushes the vitreous back, and moves the iris forward, which expands the posterior chamber and avoids the need to use a needle to pierce the iris. It also maintains the rigidity of the globe, which is important when a needle is inserted through the sclera. Two more conjunctival peritomies are created from 2 to 4 o'clock and 8 to 10 o'clock. Two scleral grooves are created that parallel the limbus and are 1.0 mm from it. The grooves are 3.0 to 4.0 mm in length, centered at 3 o'clock and 9 o'clock, and two thirds the thickness of the sclera (Figure 1, A).

Figure 1.: (Lin) A: Two conjunctival peritomies are created at 2 to 4 o'clock and 8 to 10 o'clock; 2 scleral grooves paralleling the limbus and centered at 3 o'clock and 9 o'clock are created. B: The Ethicon CIF-4 needle and the 25-gauge needle are inserted through opposite scleral grooves; the CIF-4 needle is engaged in the barrel of the 25-gauge needle. C: The 25-gauge needle is withdrawn, and a 10-0 Prolene suture is extended from the 9 o'clock groove to the 3 o'clock incision. D: The procedure is repeated at the upper end of the scleral groove. E: The corneoscleral wound is opened, and the threads are retrieved with a hook or IOL forceps and cut in half. F: Two threads at each site are tied to 1 haptic eyelet. G: The IOL is inserted and the corneoscleral wound closed with 10-0 nylon. H: The threads in the 9 o'clock groove are pulled out and cut in half. I: The needles are cut off, and the threads are tied in a releasable knot at the 3 o'clock groove. J: A 3-1-1-1 surgeon's knot is tied and the thread trimmed exactly above the knot; the knot buries spontaneously in the scleral groove.

A double-armed, 10-0 polypropylene (Prolene®) suture on an Ethicon CIF-4 needle grasped with a needle holder is inserted into the globe through the lower end of the 9 o'clock scleral groove. The needle tip passes through the ciliary sulcus and is advanced behind the iris until it is visualized behind the pupil. A 25-gauge needle slightly bent by a needle holder and with a curve similar to the CIF-4 long needle is inserted into the globe from the lower end of the scleral groove at 3 o'clock. The needle is passed through the scleral groove in the same manner as the CIF-4 needle (Figure 1, B). The CIF-4 long needle is pushed as far as possible into the barrel of the 25-gauge needle. The 25-gauge needle is withdrawn slightly to test whether it can carry the suture needle without letting it slip out.

After the 25-gauge needle is withdrawn from the globe, a 10-0 Prolene suture is extended from the 9 o'clock scleral groove to the 3 o'clock incision (Figure 1, C). The same procedure is repeated using the other arm of the CIF-4 needle at the upper end of the scleral groove. The 2 extended 10-0 Prolene sutures are parallel from 9 to 3 o'clock (Figure 1, D). After the superior corneoscleral wound is opened, both threads are retrieved from the globe with a hook or an IOL forceps and cut in half (Figure 1, E). Two threads at each site are tied at 1 eyelet of the haptic at both sites (Figure 1, F).

An IOL is inserted into the sulcus by slowly and firmly pulling the threads out of the globe simultaneously to prevent the suture from wrapping around the IOL. The other haptic is inserted in the same manner. The superior corneoscleral wound is closed with 10-0 nylon (Figure 1, G). The threads are pulled out of the globe with a forceps, providing counterpressure on the sclera. The threads in the 9 o'clock groove are pulled out in the same manner and cut in half (Figure 1, H). After the needles of both sutures are cut off, the threads from the upper and lower ends are tied in a releasable knot in the 3 o'clock groove (Figure 1, I).

After the tension of the suture and the IOL position are adjusted, 2 threads from the upper and lower parts are tied with a 3-1-1-1 surgeon's knot. The threads are trimmed exactly above the knot, and the knot is buried in the scleral groove spontaneously. The temporary knot is released at the 3 o'clock incision, and the threads are tied and trimmed as at the other site. A suture for the scleral groove is unnecessary (Figure 1, J). The conjunctiva is sutured or cauterized over the scleral incision sites.

Results

This technique was used in 10 cases that needed a secondary IOL and did not have sufficient capsule support. A Storz P366UV IOL was implanted in all eyes. All cases had good IOL centration and improved visual acuity. No suture protrusion was noted. One case had a ciliary hemorrhage during the insertion of the 25-gauge needle, but the hemorrhage stopped after ocular pressure reform and there were no late complications.

Discussion

Suture fixation of IOLs to different eye tissues have been attempted. Use of the McCannel suture is a technique to suture the IOL haptic onto the peripheral iris.⁵ Suture fixation of the PC IOL to the iris through a limbal incision has been reported by Parker and Price.⁶ Suturing the IOL through the pars plana was reported first by Girard⁷ and improved by Teichmann,⁸ but it did not become as popular as the ciliary sulcus fixation technique. An early series of ciliary sulcus-fixated sutured IOLs used the ab interno technique,^9,10 in which a long suture needle is inserted through the superior corneoscleral incision and penetrates the ciliary sulcus from the inside out.

A modified ab interno method reported by Spigelman et al.¹¹ inserts a retrobulbar needle through the superior corneoscleral incision, penetrates the ciliary sulcus from 6 o'clock, and back loads the thread through the barrel of the needle. Price and Wellemeyer¹² use a double-armed Prolene suture to fixate the IOL at 6 o'clock and 12 o'clock. They pass the thread through the hole in the haptic. The knot can be rotated into the sclera to prevent exposure of the suture. A disadvantage of ab interno techniques is that during penetration, with the needle tip obscured by the iris, the direction of the needle and the penetrating site are sometimes difficult to control.

In 1991, Lewis¹³ reported an ab externo technique that had the advantage of buried knots under the triangular flap and precise placement of scleral-fixated sutures. During the procedure, the surgeon's view is less obscured. The procedure is widely used, and part of our technique is a modification of it. The disadvantage is the time it takes to create the flap, especially under the most vascularly abundant area of the conjunctiva. Otherwise, single-point fixation may not offer enough stability and result in IOL tilting. To improve this, Lewis¹⁴ reported sulcus fixation without flaps. It is a remarkable technique, but the risk for breaking the suture during knot rotation in the eye is a major concern.

The ab externo technique offers a precise penetration site and 2-point fixation with a distance of 3.0 to 4.0 mm, providing additional IOL stability and helping to achieve centration. Different strategies have been used to bury the suture knot. One is to pull the suture through the eyelet of the IOL haptic instead of tying it, which offers the possibility of burying the suture by rotating the knot into the sclera.^12,14 A partial-thickness flap is another option.¹³

We chose scleral grooving because it is easier to create and offers enough space to bury the suture. A similar idea has been reported.¹⁵ Instead of a vertical groove, an oblique one is made to create a pocket with the button toward the limbus, which enlarges the hidden space for the suture. In our technique, only 1 suture material with a double-armed needle is used. Compared with other 4-point fixation methods that need 2 suture materials, our technique is more cost effective. Some surgeons use a straight needle. We use a curved needle because we are more accustomed to its pathway and a curved needle may decrease the possibility of piercing the iris. A needle with a small barrel such as a 28-gauge or a 27-gauge has been used in most ab externo technique series; we used a 25-gauge needle because it is longer and easier to manipulate without a syringe and the CIF-4 needle is easier to insert into the wider lumen. The potential disadvantage is that the larger needle might make it easier to induce hemorrhage, as in 1 of our cases.

Potential complications of this surgical manipulation (eg, hemorrhage, cystoid macular edema, glaucoma, retinal detachment, uveitis, choroidal detachment, and suprachoroidal hemorrhage) are similar to those in other techniques. Endophthalmitis after scleral suture fixation of a PC IOL has been reported in relation to the suture-eroded conjunctiva.^16,17 It is not known whether an open scleral groove without wound closure increases the risk for infection through the suture-penetration sites but under the cover of the conjunctiva, a well-buried suture is less dangerous than a protruding one. We conclude that our modified method to suture the IOL in the posterior chamber is safe and easy to perform, offering improved IOL centration and stability and avoiding suture exposure.