Femtosecond-assisted keratoplasty with fibrin glue–assisted sutureless posterior chamber lens implantation: New triple procedure

TECHNIQUE

Femtosecond-assisted keratoplasty with fibrin glue–assisted sutureless posterior chamber lens implantation: New triple procedure Gaurav Prakash, MD, Soosan Jacob, MS, DNB, FRCS, Dhivya Ashok Kumar, MD, Smita Narsimhan, FERC, Athiya Agarwal, MD, DO, Amar Agarwal, MS, FRCS, FRCOphth

We report a surgical technique for managing bullous keratopathy secondary to anterior chamber intraocular lens (AC IOL). The technique comprises femtosecond laser–assisted penetrating keratoplasty and AC IOL exchange with fibrin glue–assisted sutureless posterior chamber intraocular lens (PC IOL) implantation (‘‘glued IOL’’). This new triple procedure combines the unique benefits of the femtosecond laser and the glued IOL, leading to stable wound configuration, decreased opensky time, and less pseudophacodonesis, and there is less risk for the suture-related complications of transscleral suture fixation. J Cataract Refract Surg 2009; 35:973–979 Q 2009 ASCRS and ESCRS

Pseudophakic bullous keratopathy (PBK) with an anterior chamber intraocular lens (AC IOL) is a leading indication for full-thickness penetrating keratoplasty (PKP) and IOL exchange.1,2 It presents a unique surgical challenge because of a previous complicated surgery, compromised aqueous drainage, unhealthy wound configuration, and a deficient posterior capsule. Both the corneal transplantation and the IOL exchange should be optimized to achieve less ‘‘opensky’’ time, easier intraoperative procedures, faster wound healing, and maximum provision and postoperative preservation of the donor endothelial cells. A paradigm shift has occurred in keratoplasty with the use of the femtosecond laser for sculpting the donor and host corneas. The top-hat configuration has

Submitted: October 1, 2008. Final revision submitted: November 30, 2008. Accepted: December 2, 2008. From Dr Agarwal Eye Hospital and Eye Research Centre, Chennai, India. Amar Agarwal is a consultant to Abott Medical Optics (formerly Advanced Medical Optics), Irvine, California, USA. No other author has a financial or proprietary interest in any material or method mentioned. Corresponding author: Amar Agarwal, MS, FRCS, FRCOphth, Professor and Head, Dr Agarwal Eye Hospital and Eye Research Centre, 19, Cathedral Road, Chennai- 600 086, India. E-mail: dragarwal@ vsnl.com. Q 2009 ASCRS and ESCRS Published by Elsevier Inc.

resulted in a more stable wound configuration, faster healing, and more endothelial cells (compared with those in a standard manual procedure with a comparable epithelial side diameter).3–8 In contrast, current techniques for IOL exchange during keratoplasty, especially in cases with a deficient posterior capsule, are less than satisfactory. Transsclerally sutured IOLs have been used in this situation.9–10 Unfortunately, this technique is associated with a longer learning curve, prolonged intraoperative manipulation, postoperative pseudophacodonesis, and chances of postoperative decentration due to suture degradation or knot slippage.10–17 We have successfully performed fibrin glue–assisted sutureless posterior chamber IOL (PC IOL) implantation in eyes with deficient posterior capsule support.18 It involves trans-scleral exteriorization and intrascleral tuck of both the haptics under diametrically opposite scleral flaps, which are then apposed with scleral glue. This sutureless technique can be performed with routinely available poly(methyl methacrylate) (PMMA) PC IOLs and has a short learning curve. In an ongoing trial, we have achieved satisfactory surgical time and safety, rehabilitation duration, and postoperative results in more than 100 eyes with postsurgical aphakia or dislocated IOLs (unpublished data). There have been no cases of dislocation. We describe a new triple procedure: femtosecond laser–assisted PKP, AC IOL explantation, and fibrin glue–assisted sutureless IOL implantation in the posterior chamber for the management of PBK with an 0886-3350/09/$dsee front matter doi:10.1016/j.jcrs.2008.12.049

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Figure 1. Top left: Preoperative photograph showing PBK with an AC IOL in situ. Top right: Femtosecond laser– created top-hat configuration. Bottom left: Femtosecond–assisted top-hat configuration showing the predictable and uniform wound formation. Bottom right: Inferior straight sclerotomy made with an 18-gauge needle 1.5 mm from the limbus under the existing scleral flaps. Note the diametrically opposite scleral flaps.

AC IOL. The unique benefits of femtosecond laser and a ‘‘glued IOL’’ could be adjunctive and provide enhanced results in cases having PKP and IOL exchange. SURGICAL TECHNIQUE Femtosecond-Assisted Donor And Host Preparation The initial part of the surgery is done at the femtosecond laser facility. Donor buttons are prepared from whole globes. After the suction ring is applied and adequate vacuum and centration are achieved, a top-hat configuration is created using a 60 kHz femtosecond laser (IntraLase FS [IntraLase Corp.]) (Figure 1, top right, bottom left). For the host cut, the patient is given topical anesthesia. After the suction ring is applied and adequate vacuum and centration are achieved, a top-hat configuration is created. The donor cornea and patient are then moved to the keratoplasty operating room. Combined Keratoplasty and IOL Exchange with Modification for the Glued IOL The rest of the surgery is performed under peribulbar anesthesia. A limited peritomy is done in the inferotemporal and superonasal areas 180 degrees apart, and a 3.0 mm  3.0 mm area is marked on the sclera. Two partial-thickness limbal-based scleral flaps of 3.0 mm are created. Two straight sclerotomies, one slightly inferior to the other, are made with an 18-gauge needle 1.5 mm from the limbus under the existing scleral flaps (Figure 1, bottom right). The top hat is inspected for

completeness. After the host button is removed, the AC IOL is explanted (Figure 2, bottom left). Limited open-sky anterior vitrectomy is then performed. A posterior chamber 6.5 mm IOL is held with a McPherson forceps at the pupillary plane with one hand. An end-gripping 25-gauge microcapsulorhexis forceps (MicroSurgical Technology) is passed through the inferior sclerotomy with the other hand. The tip of the leading haptic is grasped with the microcapsulorhexis forceps and pulled through the inferior sclerotomy following the haptic curve (Figure 2, bottom right). The haptic is then externalized under the inferior scleral flap (Figure 3, top left). The trailing haptic is also externalized through the superior sclerotomy under the scleral flap (Figure 3, top right). After both haptics have been externalized, the graft is placed and cardinal sutures are applied (Figure 3, bottom left). With a 22-gauge needle, a scleral tunnel is created along the curve of the externalized haptic at the edge of the scleral bed of the flap (Figure 3, bottom right). The haptic is tucked into this tunnel (Figure 4, top left; higher magnification, Figure 4, top right). A similar tunnel is created in the complimentary area on the other side, and tucking is performed. Fibrin glue (Tisseel, Baxter) is reconstituted from a pack containing freeze-dried human fibrinogen, freeze-dried human thrombin, and aprotinin solution. The reconstituted fibrin glue is injected through the cannula of the double syringe delivery system under the superior and inferior scleral flaps (Figure 4, bottom left). Local pressure is applied to the flaps for 30 seconds to allow polypeptide formation. The same glue is applied in the area

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Figure 2. Top left: Augmentation of the top-hat configuration in areas that had poor laser penetration because of overlying opacity. Top right: Posterior uncut tissue dissected with a Vannas scissors. Bottom left: Explantation of the AC IOL after removal of the host button. Bottom right: Leading haptic grasped with the microcapsulorhexis forceps for being pulled through the inferior sclerotomy following the haptic curve.

between the sutures at the entire graft–host junction (Figure 4, bottom right). The conjunctiva is also apposed with the glue. Postoperatively, gatifloxacin eyedrops are prescribed 4 times a day, prednisolone acetate 6 times a day, homatropine sulfate 3 times a day, and preservative-free tear substitutes 6 times a day.

Results The triple procedure was performed in 3 patients with PBK with AC IOL (Table 1). The mean age of the patients at presentation was 46 years. The preoperative best corrected visual acuity (BCVA) was light perception, counting fingers, and counting fingers. Top-hat configuration was sculpted, with the donor

Figure 3. Top left: Leading haptic externalized completely under the inferior scleral flap. Top right: The trailing haptic externalized through the superior sclerotomy under the scleral flap. Bottom left: The graft button placed and cardinal sutures applied. Bottom right: Scleral tunnel created along the curve of the externalized haptic in the superonasal area at the edge of the scleral bed of the flap.

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Figure 4. Top left: The superior haptic tucked into the superonasal tunnel. Top right: The tucking shown at higher magnification. Bottom left: Reconstituted fibrin glue injected through the cannula of the double syringe delivery system under the inferior scleral flap. Bottom right: The glue applied at the graft–host junction.

graft oversized by 0.2 mm in all 3 cases. The femtosecond laser parameters for the donor and lenticule preparation are shown in Table 2.

The immediate postoperative course was uneventful, and the BCVA had improved to counting fingers, 6/12, 6/9, respectively, at the 1-month follow-up. The

Table 1. Characteristics of the 3 patients. Characteristic Age, y/sex Diagnosis Systemic problems Ocular problems

Preop BCVA Corneal thickness (mm) Applanation IOP (mm Hg) AL on A-scan (mm) Explanted IOL Postop BCVA (4 mo) Applanation IOP (mm Hg) Implanted IOL Implanted IOL power (D) Intraop and postop complications

Patient 1

Patient 2

Patient 3

75/ F PBK with AC IOL None None

25/M PBK with AC IOL None Conjunctival scarring with narrow palpebral aperture (secondary to viral illness)

35/M PBK with AC IOL None None

LP 648 24 22.6 AC IOL

CF 622 16 24.3 AC IOL

CF 630 18 23.2 AC IOL

CF 18 PC IOL (6.5 mm optic, 13.5 mm overall diameter) C22.5 None

6/12 12 PC IOL (6.5 mm optic, 13.5 mm overall diameter) C18.0 Preexisting fornix scarring; required canthotomy for suction ring placement

6/9 14 PC IOL (6.5 mm optic, 13.5 mm overall diameter) C21.0 None

AC IOL Z anterior chamber intraocular lens; BCVA Z best corrected visual acuity; CF Z counting fingers; LP Z light perception; PC IOL Z posterior chamber intraocular lens; PBK with AC IOL Z pseudophakic bullous keratopathy with AC IOL

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Table 2. Femtosecond laser parameters for the 3 donors and recipients. Parameter Lamellar cut Depth (mm) Outer diameter (mm) Inner diameter (mm) Lamellar energy (mJ) Tangential spot separation (mJ) Radial spot separation (mJ) Anterior side cut Posterior depth (mm) Anterior diameter (mm) Anterior energy (mJ) Anterior side-cut angle Anterior side-cut spot separation (mm) Anterior side-cut layer separation (mm) Posterior side cut Anterior depth (mm) Posterior diameter (mm) Posterior energy (mJ) Posterior depth (mm) Posterior side-cut angle Posterior side-cut spot separation (mm) Posterior side-cut layer separation (mm)

Donor 1

Recipient 1

Donor 2

Recipient 2

Donor 3

Recipient 3

275 7.8 6.1 1.40 5 5

275 7.6 5.9 1.40 5 5

275 8.8 7.1 1.40 5 5

275 8.6 6.9 1.40 5 5

275 8.4 6.7 1.40 5 5

275 8.2 6.5 1.40 5 5

305 6.2 1.45 90 2 2

305 6.0 1.45 90 2 2

305 7.2 1.45 90 2 2

305 7.0 1.45 90 2 2

305 6.4 1.45 90 2 2

305 6.2 1.45 90 2 2

245 7.7 1.45 1200 90 2 2

245 7.5 1.45 500 90 2 2

245 8.7 1.45 1200 90 2 2

245 8.5 1.45 500 90 2 2

245 8.7 1.45 1200 90 2 2

245 8.5 1.45 500 90 2 2

first case had prexisting advanced glaucoma with trabeculotomy; the BCVA did not improve much after the procedure. At the 4-month follow-up, all 3 patients maintained the 1-month BCVA. There were no episodes of keratoplasty-related problems (infection, rejection, dehiscence) or IOL-related problems (vitreous incarceration, endophthalmitis, subluxation, haptic extrusion). DISCUSSION In PKP cases, all attempts should be made to minimize endothelial cell loss in the intraoperative and postoperative periods. To provide the maximum number of endothelial cells to the host, there may be a tendency toward larger grafts in conventional keratoplasty for bullous keratopathy. However, this is associated with an increased epithelial cell load, which is probably associated with a higher risk for graft rejection.19,20 Since a top-hat configuration is larger at the inner end, it provides a greater number of endothelial cells for the same number of epithelial cells. In addition, with the top-hat configuration, smaller outer sizes can be prepared and the graft–host junction can be farther from the limbus centripetally, reducing chances of neovascularization. These 2 unique advantages of the tophat configuration may enhance graft survival by reducing chances of graft rejection and promoting endothelial survival.

We noted an incomplete cut in one case (patient 2), which was completed by manual dissection. However, the partial cuts created by the femtosecond laser acted as a template for lamellar separation. In future, with increased penetration and better laser mechanics, the more challenging scarred cornea might also be successfully sculpted. Intraocular lens exchange is arguably the more challenging step in this surgery. The safety and long-term efficacy of a transsclerally sutured PC IOL are less than satisfactory.12–14 The transsclerally sutured IOL is associated with a steep learning curve and requires special steps that an anterior segment surgeon may not use routinely. In a previous study,12 ultrasound biomicroscopy showed that transscleral suturing of an IOL had problems related to accurate suturing at the ciliary sulcus. In addition, there are issues with IOL iris contact, pigment dispersion, high aqueous flare, and vitreous incarceration. In PKP, the conventional wisdom is to reduce the ‘‘open-sky’’ duration to as short a time as possible as there is an associated risk for expulsive hemorrhage or choroidal effusion. The tamponade effect of a securely fixated IOL can be helpful in the duration between completion of host dissection and suturing of the donor button (the open-sky period). Transscleral suture fixation requires adjustment of the sutures and knots to maintain the IOL in position, leading to

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Figure 5. Diagram showing biomechanical and kinetic properties of manual keratoplasty with transscleral suture-fixated PC IOL (TSF IOL) (top) and femtosecond-assisted keratoplasty (FAK) with glued IOL (bottom). Differences between the 2 approaches are indicated by the points. Point 1, top: Haptic–suture junction in the TSF IOL, with the IOL hanging like a hammock. Point 1, bottom: Rigid PMMA haptic in glued IOL fixated with the sclera. Point 2, top: Transverse graft–host junction. Point 2, bottom: More stable top-hat configuration. Point 3, top: Size of epithelial side (outer cut) same as that of endothelial side (inner cut). Point 3, bottom: Size of epithelial side (outer cut) less than that of endothelial side (inner cut), leading to greater number of endothelial cells for smaller epithelial load and placement of sutures farther from limbus. Point 4, top: Knots in TSF IOL may degrade and slip. Point 4, bottom: Haptic is securely tucked and sealed with fibrin glue in glued IOL. Point 5, top: More pseudophacodonesis with TSF IOL. Point 5, bottom: Less pseudophacodonesis with glued IOL.

a delay in placement of the donor button. It also requires a special IOL with eye haptics and may not be readily available. An open-sky procedure is often associated with anterior vitrectomy. The resultant hypotony makes suture placement and adjustment difficult. In an opensky procedure with a deficient posterior capsule, there is no tamponade effect and the results can be disastrous if the patient strains or coughs. The aim of the surgeon in this scenario should be to reduce the surgical time. Most of the time consumption in these cases is in passing the straight needle and tying and adjusting the sutures. A glued IOL can be used as a safe and effective alternative. The new technique has a short learning curve. Most steps, except externalization and tucking, are part of routine anterior segment procedures.18 There is no requirement for an extra set of sutures and a straight needle, which can be difficult to pass in a hypotonous open globe. While doing scleral fixation with sutures, the surgeon must readjust the knots to maintain the central position of the IOL. In our procedure, simply manipulating the amount of externalization can cause proper centration of the IOL. The final tucking of the haptic provides further stabilization. A sutured scleral-fixated IOL hangs in the posterior chamber, with the sutures passing through the haptic eyes, similar to a hammock, causing dynamic torsional and anteroposterior oscillation. This pseudophacodonesis may result in progressive endothelial loss. However, in our technique, rigid haptics are used for fixation on the scleral side and the stable optic–haptic

junction prevents torsional and anteroposterior instability. Therefore, there is much less pseudophacodonesis (Figure 5). The haptics are covered in the scleral flap and tucked well inside the scleral pocket. There is an additional well-apposed layer of conjunctiva over the sclera. This further reduces the chances of haptic extrusion. Femtosecond laser–assisted keratoplasty with tophat configuration and a glued IOL provides a unique solution in cases with bullous keratopathy and AC IOLs. This is an improvement over the traditional technique of manual trephination and transscleral suture fixation of the IOL (Figure 5). The femtosecond laser’s top-hat configuration provides a greater number of endothelial cells in the donor lenticule and a more stable wound configuration. Better dynamic stability of the glued IOL prevents pseudophacodonesis and may reduce endothelial cell loss or repositioning surgery. Combined, these 2 surgical modalities may improve results. Although our initial results with this technique are good, larger comparative trials to evaluate the long-term outcome of the technique with that of manual trephination with a transscleral suture-fixated IOL will provide more conclusive evidence.

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