Ophthalmic Surgery, Lasers and Imaging Retina

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Imaging Case Report 

Corneal Imaging with Pentacam After Descemet’s Membrane Perforation During Deep Anterior Lamellar Keratoplasty

Ma Teresa Rodríguez-Ares, MD, PhD; Rosario Touriño, MD, PhD; Ma Jesús López-Valladares, MD, PhD

Abstract

The usefulness of Pentacam in the diagnosis and management of Descemet’s membrane perforation during deep anterior lamellar keratoplasty (DALK) was described and reported. A 59-year-old man with neurotrophic keratitis was operated on DALK procedure. The big-bubble technique was used without apparent complications. A double anterior chamber was observed on the first postoperative day. After days, sulphur hexafluoride (SF6) in isoexpansile concentration was successfully injected into the anterior chamber. The Pentacam (Oculus, Wetzlar, Germany) imaging was performed. Correlations between Pentacam findings and clinical signs were evaluated. Pentacam imaging is a useful technique to diagnose and document the progress of surgical complications after DALK.

Abstract

The usefulness of Pentacam in the diagnosis and management of Descemet’s membrane perforation during deep anterior lamellar keratoplasty (DALK) was described and reported. A 59-year-old man with neurotrophic keratitis was operated on DALK procedure. The big-bubble technique was used without apparent complications. A double anterior chamber was observed on the first postoperative day. After days, sulphur hexafluoride (SF6) in isoexpansile concentration was successfully injected into the anterior chamber. The Pentacam (Oculus, Wetzlar, Germany) imaging was performed. Correlations between Pentacam findings and clinical signs were evaluated. Pentacam imaging is a useful technique to diagnose and document the progress of surgical complications after DALK.

Corneal Imaging with Pentacam After Descemet’s Membrane Perforation During Deep Anterior Lamellar Keratoplasty

From the Cornea and Ocular Surface Unit, Department of Ophthalmology, Complejo Hospitalario de Santiago de Compostela, University of Santiago de Compostela, La Coruña, Spain.

The authors have no financial or proprietary interest in the materials presented herein.

Address correspondence to M. Teresa Rodríguez-Ares, Cornea and Ocular Surface Unit, Department of Ophthalmology, Complejo Hospitalario Universitario de Santiago de Compostela -Hospital de Conxo, Rúa Ramón Baltar s/n, CP: 15706, Santiago de Compostela. La Coruña. Spain.

Accepted: October 31, 2008
Posted Online: March 09, 2010

Introduction

Deep anterior lamellar keratoplasty (DALK) is a partial thickness corneal graft, which replaces the affected stroma and retains the corneal endothelium. Its main advantage over penetrating keratoplasty is the reduction of the risk of graft rejection after surgery. The big-bubble technique is a well known method that takes advantage of the loose adhesion between Descemet’s membrane (DM) and the posterior stroma. It uses pneumatic pressure to detach DM by injecting air into the deep stroma through a 30-gauge needle. The injected air produces a dome-shaped DM detachment that can be identified by a ring under the surgical microscope, creating the big bubble. To facilitate DM separation from the stroma, viscoelastic injection into the intervening space can be used.

The attempt to bare DM can be complicated by its perforation which can cause collection of aqueous at the recipient-donor interface (double anterior chamber)1. The incidence of Descemet’s membrane perforation during DALK varies from 4% to 40%, and depends on the technique and the programmed depth.2–4 When a DM perforation occurs during surgery, air injection into the anterior chamber should be performed at the end of the procedure.

We report a case of a DM perforation during DALK, detected on the first-postoperative day as a double anterior chamber which was successfully treated with an intracameral injection of sulphur hexafluoride (SF6) in isoexpansile concentration. Correlations between Pentacam® (Oculus, Wetzlar, Germany) findings and clinical signs were evaluated.

Case Report

56-year-old man was referred to the clinic for deep corneal scarring and vascularisation after a long history of neurotrophic keratitis, related with herpes infection in his right eye. Best-corrected visual acuity was reduced to counting fingers (at 1 m).

The big-bubble surgical technique was performed. A Hessburg-Barron (Katena Products, Denville, New Jersey, USA) suction trephine (7.5 mm) was used for partial thickness trephination of the host cornea up to an approximate depth of 350 μm. A 30-gauge disposable needle bent at 90º was advanced in the paracentral stroma, and air was injected into the corneal stromal tissue forming a large air bubble between DM and the host stroma (Fig. 1A). An anterior keratectomy was then carried out with a sharp crescent blade and a paracentesis was performed (Fig. 1B). The stromal flaps were removed with scissors. The donor button was cut using an 8 mm Barron punch and then DM was scraped off after staining it with 0.06% trypan blue dye (Vision blue, Dorc International, Netherlands). Then, donor button was secured over the recipient bed with 16 interrupted sutures (10/0 monofilament).

Intraoperative Images During Deep Lamellar Keratoplasty Showing the “big Bubble”, Seen as a Circular Disk with Dense White Edge (A). In (B) We Can See the Anterior Keratectomy with a Sharp Crescent Blade.

Figure 1. Intraoperative Images During Deep Lamellar Keratoplasty Showing the “big Bubble”, Seen as a Circular Disk with Dense White Edge (A). In (B) We Can See the Anterior Keratectomy with a Sharp Crescent Blade.

No defect or tear in the DM was noted during the surgery. In the early postoperative period, the patient received 0.3% ciprofloxacin drops four times daily, unpreserved dexamethasone 0.1% drops four times daily, preservative-free artificial tears every two hours and valacyclovir 500 mg two times daily.

On the first postoperative day, the graft was very edematous, with central corneal thickness of 1066 μm. A detachment between the recipient DM and the swollen donor cornea was suspected when a double anterior chamber was noticed (Fig. 2A). This clinical image was confirmed by Scheimpflug images from OCULUS Pentacam® (Oculus, Wetzlar, Germany) which showed with great detail the DM detachment and a double anterior chamber (Fig. 2B).

First Postoperative Day. (A) Severe Corneal Edema and Double Anterior Chamber Seen in Slit Lamp Examination. (B) Scheimpflug Images (pentacam): Descemet’s Membrane Detachment and Double Anterior Chamber.

Figure 2. First Postoperative Day. (A) Severe Corneal Edema and Double Anterior Chamber Seen in Slit Lamp Examination. (B) Scheimpflug Images (pentacam): Descemet’s Membrane Detachment and Double Anterior Chamber.

Since spontaneous resolution of the DM detachment can occur in the next days in some cases, we decided to wait. However, on the 14th postoperative day severe graft edema was still present so we decided to inject intracameral 20% sulphur hexafluoride gas (SF6) for tamponade between the host’s DM and the overlying donor graft. Afterwards, examination with OCULUS Pentacam® was carried out to confirm the correct reapposition of DM on the overlying stroma (Fig. 3A). Over the next two weeks, the Descemet detachment resolved and corneal edema clear completely.

(A) Scheimpflug Images. Sulfur Hexafluoride (SF6) Bubbles in the Anterior Chamber Immediately After the Gas Injection, Pushing the Descemet’s Membrane Against the Stroma. (B) Descemet’s Membrane Reapposed 3 Months After the Deep Anterior Lamellar Keratoplasty.

Figure 3. (A) Scheimpflug Images. Sulfur Hexafluoride (SF6) Bubbles in the Anterior Chamber Immediately After the Gas Injection, Pushing the Descemet’s Membrane Against the Stroma. (B) Descemet’s Membrane Reapposed 3 Months After the Deep Anterior Lamellar Keratoplasty.

At 3 months, post-DALK slit lamp examination showed a clear cornea with just a few endothelial folds. Scheimpflug images from OCULUS Pentacam® confirmed the resolution of the DM detachment and the reduction of the corneal thickness (600 μm). However, in the graft-host junction appeared a hyperreflective line (Fig. 3B). The visual acuity improved to 20/50 with pinhole.

Discussion

DALK is usually carried out to treat a wide range of corneal pathologies without endothelial involvement. Several techniques have been used to facilitate lamellar dissection5–7. One of them uses air to create a plane of dissection between the DM and the corneal stroma6. However, this technique is difficult to perform and DM perforation is a common complication.

In this case, we did not observe this complication during surgery but the severe graft edema and the double anterior chamber found on the first postoperative day were highly suspicious of this complication. Pentacam® Scheimpflug images confirmed the diagnosis and delineated the DM detachment.

The OCULUS Pentacam® system uses a rotating Scheimpflug camera and an ultrafast processor to obtain 50 slit images and provide a comprehensive, 3-dimensional (3-D) scan of the anterior chamber, from the anterior surface of the cornea up to the posterior surface of the crystalline lens. This non-contact procedure/examination is rapid and accurate. During the scan, fixation control is achieved via a second camera focused on the pupil that monitors size and orientation in order to detect eye movement which is automatically corrected until the scan is completed. Obtained data are analysed with sophisticated software to produce multiple representations of the anterior segment and an extensive list of key measurements that make the Pentacam useful in a broad spectrum of applications: topography maps, corneal pachymetry map from limbus-to-limbus, anterior segment analyses providing data on chamber angle, chamber height, chamber volume and densitometry data for cornea and crystalline lens analyses.

Management of DM perforation depends upon the size and localization of the defect. Some authors8 have reported resolution of this type of detachment by injecting air into the anterior chamber, however, when a pseudoanterior chamber is found, air injection can not be helpful to obtain complete graft apposition to the DM. In these cases, injection of gases such as SF6 into the anterior chamber can be useful9,10. In our patient, the injection of 20% SF6 healed the detachment and reduced both corneal thickness and edema.

We carried out Pentacam® Scheimpflug image captures immediately after intracameral gas injection, which allowed us to check the correct position of the SF6 bubbles pushing DM to the overlying cornea in the anterior chamber. 3 months after DALK procedure, the cornea remained clear and anterior segment Pentacam® images confirmed a good anatomic result. However, a hyperreflective line in the graft-host junction was found. Other authors11 have reported similar lines in lamellar keratoplasty procedures using anterior segment optical coherence tomography in the evaluation of the cornea. These lines can correspond with DM (in cases of DALK) or lamellar interface (in cases of DSAEK). In our case, the hyperreflective line appears to be a thicken DM.

In conclusion, cornea and anterior chamber structure images afforded by non-contact three dimensional analyzer Pentacam® seems to be a useful technique for the diagnose and management of complications in corneal surgery.

References

  1. Soong HK, Katz DG, Farjo AA, et al. Central lamellar keratoplasty for optical indications. Cornea. 1999;18:249–256. doi:10.1097/00003226-199905000-00001 [CrossRef]
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  11. Lim LS, Aung HT, Aung T, Tan DTH. Corneal imaging with anterior segment optical coherence tomography for lamellar keratoplasty procedures. Am J Ophthalmol. 2008;145:81–90. doi:10.1016/j.ajo.2007.08.019 [CrossRef]
Authors

From the Cornea and Ocular Surface Unit, Department of Ophthalmology, Complejo Hospitalario de Santiago de Compostela, University of Santiago de Compostela, La Coruña, Spain.

The authors have no financial or proprietary interest in the materials presented herein.

Address correspondence to M. Teresa Rodríguez-Ares, Cornea and Ocular Surface Unit, Department of Ophthalmology, Complejo Hospitalario Universitario de Santiago de Compostela -Hospital de Conxo, Rúa Ramón Baltar s/n, CP: 15706, Santiago de Compostela. La Coruña. Spain.

10.3928/15428877-20100215-20

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