Spontaneous resolution of double anterior chamber with perforation of Descemet's membrane in deep anterior lamellar keratoplasty.

Deep anterior lamellar keratoplasty (DALK) using Dr. Anwar's big bubble technique was performed for a patient with granular dystrophy. Intraoperatively, a perforation of the Descemet's membrane (DM) was noted inferonasally. Though the surgery was completed, the donor graft appeared to have an intact endothelium, which was inadvertently left behind by the surgeon. Intraoperatively, there was a perforation of inferonasal DM and surgery was completed by inadvertently placing a donor with an intact endothelium. Postoperatively the patient presented with a complete DM detachment and a resultant double anterior chamber (DAC). In spite of two attempts at an air tamponade on the first and fifth post operative days, the DAC still persisted. Surprisingly, during the 6(th) week follow up visit, there was a complete resolution of the DAC as well as total recovery of vision. This interesting case clearly exemplifies that, in spite of failed attempts at air tamponade, a DM detachment and a DAC due to DM perforation following a DALK procedure can resolve spontaneously with good visual outcome.

Introduction

Deep anterior lamellar keratoplasty (DALK) using “Anwar big-bubble technique,” facilitates the successful completion of DALK.[1]

Inadvertent rupture of DM has been reported when DALK is performed in keratoconus patients where thinning is present with advanced cones.[2]

Here we report a patient with granular dystrophy, who developed a DM detachment and double anterior chamber following big-bubble DALK as a result of perforation of DM intra-operatively and its outcome.

Case Report

A 79-year-old gentleman with granular dystrophy OU had best corrected vision of 20/200 in both eyes was advised DALK for the left eye [Figure 1]. A 7.5-mm-diameter partial thickness trephination of the recipient cornea to an approximate depth of 300 to 350 mm was performed, and the anterior half of cornea was dissected and removed. A 30-gauge needle was inserted into the residual corneal stroma and air was injected with a continuous force using a 5 ml syringe till a bubble was formed. A 15 degree side port knife was used to cut open the residual stroma. The stromal tissue was cut over the spatula and the quadrants were cut at the edge of the trephination using corneal scissors. During this stage a small perforation occurred in the inferonasal quadrant. Since the perforation was small it was decided to continue with DALK. But inadvertently the endothelium of the donor was not removed and was secured with 16 interrupted sutures. Air was injected into anterior chamber at the end of the procedure. On the first postoperative day, a double anterior chamber was noted [Figure 2] with a complete DM detachment. Air tamponade was tried unsuccessfully on day 2 and day 5. The fluid was drained at the graft host junction after injecting air into the AC. On the 5th post operative day, the DAC still persisted. Since the vision was stable at 20/60 unaided as a consequence of a clear donor graft, it was decided that we should wait and observe, as against any further intervention. When then the patient returned after 4 weeks the double AC was resolving. At 6 weeks we were surprised to observe that the double AC had completely disappeared with a clear corneal graft and vision of 20/30 with -1.5D sphere and -1.75D cyl @ 165. [Figure 3]

Figure 1

Pre-operative slit lamp photograph of OS showing Granular dystrophy

Figure 2

Anterior segment photograph on first post-operative day showing a Double Anterior Chamber (arrow)

Figure 3

Anterior segment photograph showing spontaneous resolution of the double anterior chamber

Discussion

DALK is indicated for disorders of the cornea in the setting of a healthy endothelium. Indications for DALK include corneal scars from healed infectious keratitis or superficial trauma, anterior corneal dystrophies, stromal corneal dystrophies, and ectatic disorders such as keratoconus and pellucid marginal degeneration.[3] A popular technique for cleaving the stroma at a predetermined depth for DALK is the Big Bubble technique of Anwar.[1] Here injection of air bubble into the deep stroma cleaves the posterior stroma leaving behind a clear DM. The other techniques used to separate DM from include injection of saline or viscoat. If a scarring or dehiscence of DM is suspected layer by layer manual dissection is done to remove the stroma. DM can be perforated during trephination, while injection of air to create a bubble, or during removal of anterior stroma with the scissors perforating the DM especially at the site of partial adhesion. Small perforations (less than 1 mm) can be managed by decompressing the AC and continuing with the procedure. Large perforations need to be converted to penetrating keratoplasty (PKP). This paper is for a perforation due to a full thickness trephination. Ours is a perforation during separation of DM after bubble. The incidence of DM perforation during DALK depends on the technique and the programmed depth. Reported incidences vary from 4.4% to 39%.[4-7] Some surgeons abandon DALK and convert to PKP whenever a perforation occurs, a strategy not justified as studies show it leads to poorer visual results.[6] After perforation, the rate of immediate conversion to PKP in the recent reports ranges from 0% to 100%.[56] Double AC can occur in patients with inadvertent perforation due to influx of aqueous into the potential space between the donor and the recipient. This usually resolves with a tight air fill of the anterior chamber. A previous study showed that air was injected in the AC to visualize the posterior corneal surface induced a mean cell loss of 22.5% at 3 months. Multiple air injections might be associated with more severe endothelial damage.[13]

Reviewing our case, a DM perforation was noted intraoperatively. Since the perforation was small, the stroma was dissected completely. Inadvertently, a donor was placed with an intact endothelium. There was a total double anterior chamber on the first postoperative day. Although air was injected into anterior chamber to seal the DM perforation, it was unsuccessful. In this situation we attributed the double AC to a three reasons [Figure 4]. Firstly, aqueous was making its way between the donor and recipient through the perforation. Secondly, functioning donor endothelium, inadvertently left behind, was pumping fluid into the potential space between the donor and the recipient DM. The third factor could be a transient dysfunction of the traumatized recipient endothelium. Once the endothelial cells have restored their inter cellular complexes and layer integrity, pump and barrier functions return. Subsequently, this eliminates the double chamber and aides in re-attaching DM. Postoperatively, the corneal endothelium may maintain its viability and resume function after prolonged detachment from the stromal bed.[3] Return of normal pumping produces a pressure gradient between the 2 chambers, pumping fluid from the interface of secondary chamber to the main anterior chamber. This in turn promotes reattachment. There was a delayed resolution of DAC because of intact donor endothelium pumping the fluid from stroma into the space, thus maintaining a clear graft.

Figure 4

Possible causes of double anterior chamber in our patient

A DM perforation intra-operatively during DALK can be managed by decompressing the AC and by careful dissection of residual stroma. There is a risk of double anterior chamber formation due to the existing perforation which will resolve spontaneously over 4-6 weeks giving good visual recovery. There are reports of spontaneous resolution of DM detachment following phacoemulsification as well as in cases of DALK without DM perforation.[89] Our case shows that spontaneous resolution of DM detachment is possible over a period of few weeks especially in cases with small intra-operative DM perforations.