Surgical Technique

A simple snare for transscleral fixation of dislocated intraocular lenses

Alex Poon, MB BS* J Ben Clark, FRACS, FRACO* Rodney HB Grey, FRCO? Richard H C Markham, FRCOT

Abstract

Purpose: The construction and use of a surgical snare in retrieving and securing posterior chamber intraocular lenses is described.

Methods: The snare consists of a 10 -0 polypropylene suture threaded into a 25-gauge ret- robulbar needle. This is used after a pars plana vitrectomy to retrieve the dislocated intraocular lens. The needle attached to the polypropylene suture is used to secure the lens haptic 1.5mm behind the limbus. Two snares are used to secure the two lens haptics.

Conclusions: The snare is easy to make with readily available materials. The use of this snare involves less intraocular and extraocular manipula- tions than other described methods.

complicated cataract surgery, and occasionally after over-vigorous removal of opacified poste- rior capsule dur ing vitreous surgery on pseudophakic patients. One alternative in recti- fying the problem is to reposition and securely fix the intraocular lens into the ciliary sulcus either with transscleral or iris fixation. A closed- eye technique to achieve this is probably the safest and requires some kind of snare device to retrieve and fix the haptics. Previously described devices have either been expensive or have required complex suturing and

We describe a technique for retrieval and transscleral fixation of dislocated intraocular lenses using a surgical snare that can be easily made with readily available disposable sutures and needles.

Key words: Dislocation, posterior chamber intraocular lens, snare.

Complete dislocation of a posterior chamber intraocular lens (PCIOL) into the posterior segment is an uncommon event. It can occur as a result of inadequate capsular support after

Materials and methods

Making the snare

We used a 37mm blunt 25-gauge retrobulbar needle, a 23 cm 10-0 polypropylene monofila- ment suture and a disposable 5mL syringe. One needle is cu t off a t its attachment to the

* Geelong Hospital. TBristol Eye Hospital. Reprints: Dr A Poon, RoyalVictorian Eye and Ear Hospital, 32 Gisborne St, East MelbourneVictoria 3002.

A simple snare for transscleral fixation of dislocated intraocular lenses 385

double-ended suture and the suture is folded in half, and the folded end is twisted. (Figure 1) The twisted end is then passed through the retrobulbar needle from the sharp end and is retrieved at the hub. (Figure 2) There is now the suture needle and the free end of the suture hang- ing out of the sharp end of the retrobulbar needle.The free end is now passed into the sharp end of the retrobulbar needle and retrieved at the hub as well. (Figure 3) There is now a loop of suture hanging from the retrobulbar needle tip together with the suture needle. The dispos- able 5mL syringe is then jammed into the hub of the needle to secure the suture. (Figure 4) This is repeated as two snares are required.

Operation

A three-port pars plana vitrectomy approach is used. Sclerotomies are placed V m m behind the limbus. Two partial-thickness triangular scleral flaps are fashioned at 12 and 6 o’clock. (Figure 5) Routine vitrectomy is performed if this has not been performed previously. One retrobul- bar needle (snare) is now passed into the eye 1.5mm behind the limbus beneath the 12 o’clock scleral flap.The loop of the snare is placed around one of the haptics. Intraocular forceps can be used via a vitrectomy port to manipulate lens haptic and snare. The PCIOL is pulled towards the superior ciliary body as the snare is with- drawn from the eye. (Figure 6) Now the suture is looped around the haptic with the two ends of the suture outside the eye, and a bulldog clip is used to secure the suture outside the eye. A second snare is inserted into the eye beneath the inferior scleral flap and the loop placed around the opposite haptic. (Figure 7) The snares are pulled tight until the lens is well centered and secured by the sutures looped around the supe- rior and inferior hapt ic . T h e tension is maintained by bulldog clips on both snares. One suture is then pulled out of the retrobulbar needle and the attached curved needle is passed into the scleral bed beside the entry site of the snare, and is tied.The same is done for the infe- rior suture. The scleral flaps and the three pars plana ports are closed with 8-0 vicryl sutures.

Discussion

Various techniques have been described for retrieving and securing the lens where a PCIOL has dislocated into the vitreous cavity. 1234s-8 The goals of any technique should be to do the above with minimal trauma to the eye, achieve a stable long-term result and not cause any complica- tions. We have described here a simple method of retrieving and securing the dislocated PCIOL in the ciliary sulcus with transcleral fixation. The snare is made easily from readily available mate- rial. Special suture needles described in other paper^^,^ and specially manufactured instru- m e n t ~ ~ , ~ are not required.

One reported technique requires a limbal incision to externalise the PCIOL before fixa- tion.6 A large limbal wound adds insult to the eye and thus we believe a closed-eye technique is safest. Our technique uses the standard pars plana vitrectomy ports plus 25-gauge scleral punctures through which the lens is fixated.

Intraocular manipulation of the PCIOL into the ciliary sulcus without fixation with a suture has been r e p ~ r t e d . ~ Most surgeons would, how- ever, prefer to fix the PCIOL to either iris or sclera to ensure lens stability. Suture fixation to iris involves passage of a large needle through the cornea-limbus into peripheral iris, catching the haptic behind the iris and then out again through the same s t ruc ture~ .~ Problems that may occur include intraocular bleeding, decreased pupillary dilatation, iris chafe, pseudophacodonesis, chronic inflammation, and secondary cystoid macular ~ e d e r n a . ~ , ~ It may also be difficult to get directly opposing iris fixations, which is impor tan t for lens centration.’ Several techniques have been described for transcleral fixation of a posteriorly dislocated PCIOL in a closed eye. 1-33839 These involve blind passes of needles through the ciliary sulcus and bleeding may also be a problem. A potentially devastating complication is endophthalmitis secondary to conjunctival erosion by the suture ends and the penetration of the eye by organ- isms via the suture track.5 This risk may be greater if the fixation suture is passed through the relatively large vitrectomy p0rts.l Our snare makes a small opening compared with one that

386 Australian and New Zealand Journal of Ophthalmology 1996; 24(4)

Figure 1 The 10-0 polypropylene suture is folded in halfand the folded end is twisted

1

I

Figure 2 The twisted end of the 10-0 polypropylene suture is passed through the retrobulbar needle from the

sharp end.

I 1

Figure 3 The free end of the suture is passed into the retro- bulbar needle beside the twisted end. The loop of suture hanging off the sharp end of the retrobulbar needle is the

snare used to retrieve the PCIOL haptics.

I I

Figure 4 A syringe is jammed into the hub of the retrobul bar needle to prevent slippage of the suture.

5 I Figure 5 Surgeon’s view of the right globe. 1 = sclerostomy site for infusion cannula; 2,3 = sclerostomy sites for vitrectomy instruments; 4,5 = sclerostomy sites for snares. Sutures aretied beneath a triangular partial thickness scleral

flap.

Figure 6 Diagram showing the snare being passed around one of the lens haptics in order to retrieve the PCIOL.

I I

I I Figure 7 Diagram showing one haptic secured in the ciliary sulcus, with the other haptic in the process of being

secured.

A simple snare for transscleral fixation of dislocated intraocular lenses 387

is necessary for an intraocular instrument and is placed away from the vitrectomy ports. 10-0 prolene suture is used to obtain a smaller suture track as compared to larger diameter su ture~ .~J’ The scleral bite is taken away from the scleros- tomy and the polypropylene suture is tied beneath the partial-thickness scleral flap so that there are no exposed suture ends. We believe these steps decrease the risks of fistula forma- tion and endophthamitis.2,9

To grip the PCIOL in the vitreous cavity, some authors have used intraocular f ~ r c e p s . ~ - ~ To secure the PCIOL while it is in position, the passage of a curved suture needle into the eye and the intraocular handling of this needle has been ~ u g g e s t e d . ~ Our method involves less intraocular manipulation as the snare used to grasp the PCIOL is also the suture that will secure it to sclera. With the suture needle attached to the snare, the securing of the PCIOL extraocularly by passing the needle into adjacent sclera is simple compared to other techniques. There is not the need to transfer the PCIOL from a snare to a fixation suture intraocularly, there- fore minimising intraocular manipulations and the number of times instruments are passed into the eye.

There is the potential problem of lens tilt on its vertical axis with two-point fixation, however many authors have described good long-term lens stability with two-point scleral fixated PCIOL.1J~9 The use of four-point fixation may increase unnecessarily the risk of bleeding and other complications.

Simplicity is the major advantage of this

technique for retrieval and scleral fixation of a dislocated intraocular lens. Using readily avail- able materials, this technique minimise intraocular manipulations and allows stable fixa- tion of a PCIOL.

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