Tenon patch graft with vascularized conjunctival flap for management of corneal perforation

Abstract

Purpose:

Traumatic paracentral corneal perforations may lead to irregular astigmatism and opacification from lamellar grafts. We present an alternative surgical technique using a Tenon graft and a conjunctival flap.

Methods:

A 42-year-old male presented with a 1mm paracentral corneal defect six weeks following penetrating trauma by a metallic foreign body. A region of Tenon fascia was excised and sutured to cover the perforation, and a conjunctival flap was then created and sutured over this Tenon graft. A bandage contact lens was placed postoperatively. Serial imaging was conducted to document healing including optical coherence tomography (OCT) and slit-lamp photography.

Results:

At postoperative day 1, uncorrected distance visual acuity (UDVA) was hand motion, the anterior chamber was formed and OCT revealed Tenon fascia and conjunctiva covering the defect. By postoperative week 2, the leak resolved and UDVA was 20/30. At postoperative week 4, UVDA improved to 20/20, the Tenon graft was noted to be undergoing contraction, and a single feeder vessel remained prominent in the conjunctival flap. By postoperative month 4, UVDA was 20/25 and only mild paracentral cornea clouding was noted. Initial, focal steepening and thickening normalized by month four, leaving mild, normal astigmatism. OCT revealed integration of the Tenon graft into the corneal stroma.

Conclusion:

For paracentral corneal perforations, a Tenon graft in conjunction with a conjunctival flap may aid healing with favorable postoperative refractive outcomes.

INTRODUCTION

Corneal perforation can result from penetrating trauma or from corneal stromal melt secondary to autoimmune disease, infection, or other causes of inflammation. Perforation can lead to blinding complications such as hypotony, iris synechiae, cataract, and endophthalmitis unless promptly repaired.

Closure of corneal perforation can be challenging. Although small perforations <2mm in diameter may eventually seal after application of fibrin or cyanoacrylate glue,¹ fibrin glue dissolves within 1–2 weeks and cyanoacrylate glue can become dislodged from the perforation site leading to re-opening of the perforation. Moreover, such glues may be limited by cost, accessibility, or strict storage requirements.² Surgical closure with direct suturing, patch grafting with corneal or scleral tissue, or penetrating lamellar keratoplasty can provide definitive restoration of the anterior chamber in larger perforations, but based on location, all three techniques can also impair functional vision due to induced astigmatism and/or opacification within the central cornea. Attempts at direct closure in larger perforations may be unsuccessful due to inability to reliably appose edges of corneal tissue. In cases of allografts, an extended healing period up to one year may be necessary prior to suture removal. These limitations highlight the need for an approach that minimizes surgically induced astigmatism and provides a rapid course of healing.

Tenon fascia is composed of thick, white fascia with smooth muscle fibers anterior to the equator and extends posteriorly as a thin and translucent layer extending to the optic nerve.³ The ubiquitous nature of this tissue provides an opportunity to mobilize it for patching defects. Its fibroblasts allow for a robust wound healing response.⁴ Several approaches have been described using Tenon fascia to seal perforations. For limbal perforations, a rotational flap has been advocated, which draws on the vasculature of Tenon and allows for conjunctiva to grow onto the surface.^5,6 A “Tuck-In” approach has been demonstrated for incisions up to 5mm in diameter, utilizing a stromal pocket and tucking in the Tenon into the stroma surrounding the perforation; reported outcomes have been encouraging with mean duration of healing of 25.7 days.⁷ Tenon tissue can also be tucked into the plane of corneal wound burn incisions from cataract surgery to facilitate wound plugging and fibrosis.⁸ A sutureless glued approach has been described for large perforations up to 6mm in diameter, using glue to seal, graft, and fill the depth of the defect.⁹

Here, we describe the application of Tenon fascia for closure of a 1mm paracentral defect, for which the use of a corneal patch graft would have resulted in significant vision impairment due to its relatively central location on the cornea. We also describe use of a temporary pedicled conjunctival flap to further facilitate rapid healing and integration of the Tenon patch graft into surrounding corneal stroma. We use serial multimodal imaging with slit lamp photography, Scheimpflug tomography, anterior segment optical coherence tomography (ASOCT), and specular microscopy to demonstrate the technique’s course of healing, effects on keratometry, and effects on the corneal endothelium.

MATERIALS AND METHODS

A 42-year-old male auto mechanic with no significant past medical history initially presented with a 0.5 mm metallic foreign body embedded inferior paracentral in his right cornea. The metallic foreign body was removed at the slit lamp with a 30g needle and the patient was prescribed topical moxifloxacin eye drops and erythromycin ointment for 2 weeks. Six weeks later, the patient presented with sudden onset of blurred vision, eye pain, and photophobia. Uncorrected distance Snellen visual acuity (UDVA) was 20/600 pinhole 20/40 in the right eye and 20/20 in the left eye. Intraocular pressure was 4 mm Hg in the right eye and 11 mm Hg in the left eye. Slit lamp exam revealed a 1mm diameter inferior paracentral corneal perforation with iris plugging, no stromal infiltrate, and a flat anterior chamber. The decision was made to repair the small paracentral sterile corneal perforation using autologous Tenon patch graft with conjunctival flap.

Tenon patch graft

After the anterior chamber was formed with viscoelastic material, a crescent blade was used to remove residual rust ring material within the perforation and debride a 2 mm margin of corneal epithelium surrounding the perforation (Figure 1A). To permit controlled visualization and incision of the conjunctiva, a 30 gauge needle was used to administer subconjunctival lidocaine and epinephrine and cause shallow ballooning of the inferonasal conjunctiva. Beginning at the limbus closest to the corneal perforation, the conjunctiva was incised radially in an inferonasal direction, taking care to avoid transecting prominent conjunctival blood vessels in order to preserve arterial supply within the conjunctival flap (Figure 1B–C).

Figure 1.

Surgical technique. (A) Epithelial debridement around corneal perforation. (B) Radial conjunctival incision and harvesting of Tenon autograft. (C) Creation of conjunctival pedicle flap. (D) Suturing Tenon patch graft into perforation. (E) Suturing conjunctival pedicle flap overlying Tenon patch graft. (F) Final intraoperative appearance.

Blunt subconjunctival dissection was performed to expose inferonasal Tenon fascia. We excised an area of Tenon fascia measuring 1.5mm larger in each dimension than the size of the corneal perforation (Figure 1D). The fascia was debrided of conjunctival tissue and placed over the perforation site while maintaining its original orientation (posterior Tenon facing the cornea, anterior Tenon facing externally). The Tenon patch graft was sutured using three 10–0 polyglactin (Vicryl) sutures passed full thickness through the Tenon fascia, partial-thickness into the stromal wall of the perforation, and out of the surrounding cornea. Care was taken to pass sutures outside the central optical axis to prevent visually significant scarring. To avoid cheese-wiring of suture through the patch graft as it contracted postoperatively, the patch graft was not stretched too tightly over the perforation and suture knots were not rotated through the tissue.

Conjunctival flap

Conjunctival tissue was manipulated using fine non-toothed forceps to avoid damaging vessels. Starting from the radial conjunctival incision, a conjunctival peritomy was extended inferiorly for 2 clock hours, resulting in an inferior conjunctival flap of sufficient size to cover the corneal perforation (Figure 1C). The conjunctival flap was used to cover the Tenon patch graft and sutured into place with four 10–0 polyglactin sutures placed in simple interrupted fashion with partial thickness passes taken through the cornea. Care was taken to avoid suturing through conjunctival vessels and to avoid excess tension on the conjunctival flap to prevent sutures from cheese-wiring through the conjunctival tissues (Figure 1E–F). The conjunctival incision in the area of the Tenon donor site was closed with a single 10–0 polyglactin suture. The anterior chamber was irrigated with balanced salt solution and confirmed to be watertight including through the perforation. An extended-wear bandage contact lens (BCL) was placed.

RESULTS

Figure 2A–B show slit lamp photographs of the patient’s surgical site on postoperative day 1 and postoperative month 4. On postoperative day 1 the patient’s UDVA was hand motions in the operative eye. For the first two weeks after surgery he had a small leak through the surgical site, but the chamber was formed and the patient continued wearing the BCL to tamponade the surgical site. He was prescribed prednisolone acetate 1% once per day, ofloxacin 4 times per day, and aqueous suppression with dorzolamide-timolol 2 times per day.

Figure 2.

Slit-lamp photographs of Tenon patch graft. Yellow arrows indicate the area of corneal perforation. (A) At postoperative day 1, the Tenon patch graft is sutured into the sidewall of the full-thickness corneal stromal defect with 10–0 polyglactin (Vicryl) sutures. A vascularized pedicled conjunctival flap covers the Tenon patch graft and is secured to the cornea using 10–0 polyglactin sutures. (B) At postoperative month 4 following conjunctival flap takedown, the full-thickness corneal defect has completely filled in. The corneal surface in the area of the previous conjunctival flap has epithelialized. The patient had uncorrected Snellen distance visual acuity of 20/25.

At postoperative week 2 UDVA was 20/30, the leak had resolved, the BCL was continued to prevent rubbing of the surgical site, and the patient was kept on ofloxacin 4 times per day. At postoperative week 4 UDVA was 20/20, the Tenon patch graft appeared to be undergoing contraction, and three of the polyglactin sutures within the patch graft were removed at the slit lamp. At this point the conjunctival flap was noted to have prominent vascularity with a single feeder vessel extending superiorly to the perforation site. At postoperative week 10 UDVA was 20/25, the perforation appeared to be completely filled in, the BCL was removed, and ofloxacin was discontinued. The patient resumed weightlifting without complication.

Final follow-up at postoperative month 4 showed UDVA 20/25, complete epithelialization of the corneal surface with no tear film irregularity, spontaneous regression of conjunctival vessels, and complete tissue regeneration within the perforation site with only mild loss of clarity outside the central cornea (Figure 2B).

Figure 3A–C shows serial anterior segment optical coherence tomography (ASOCT) images of the surgical site at postoperative day 1, week 2, and month 4. Although the conjunctival flap and Tenon patch graft initially formed a bleb-like covering over the perforation site which required tamponade with a BCL, the stromal defect had begun to fill in by 2 weeks and had completely filled in at 4 months. Figure 4A–B shows serial Scheimpflug imaging at postoperative day 1 and month 4. Although the inferior cornea showed focal steepening and thickening near the site of the conjunctival flap at postoperative day 1 while sutures were still in place, four months later after sutures had been removed the inferior steepening and thickening were significantly reduced, with anterior corneal curvature mapping showing essentially regular astigmatism. Figure 5A–B shows postoperative endothelial cell density at 2 months after surgery (1730 cells/mm²) and 4 months after surgery (1792 cells/mm²). For comparison, endothelial cell density in the unaffected left eye was 2597 cells/mm² (Figure 5C).

Figure 3.

Serial anterior segment optical coherence tomography after Tenon patch graft for corneal perforation. (A) At postoperative day 1, the Tenon patch graft and conjunctival flap cover the perforation and the entire surgical site is tamponaded by a bandage contact lens. (B) At postoperative week 2, the conjunctival flap and bandage contact lens are still maintaining a seal over the site of perforation. Early fill-in of Tenon tissue into the corneal stromal defect has begun, but the defect has not completely filled in. (C) By postoperative month 4, the perforation site has completely filled in and sealed with integration of Tenon tissue into the corneal stroma.

Figure 4.

Scheimpflug imaging of the cornea after Tenon patch graft for corneal perforation. (A) At postoperative day 1, when sutures were still in place, the cornea had focal steepening and thickening overlying the site of the conjunctival flap and polyglactin sutures. (B) At postoperative month 4, after sutures were removed, the inferior steepening and thickening were significantly reduced, and anterior corneal curvature showed essentially regular astigmatism.

Figure 5.

Specular microscopy demonstrates stable endothelial cell count after Tenon patch graft for corneal perforation in the right eye. (A) At 2 months after surgery, endothelial cell density in the right eye was 1730 cells/mm². (B) At 4 months after surgery, cell density in the right eye remained stable at 1792 cells/mm². (C) Endothelial cell count in the unaffected left eye was 2597 cells/mm².

DISCUSSION

In this case report, we demonstrate that Tenon patch grafting of a paracentral perforation can be performed with a good refractive outcome, minimizing astigmatism and with an acceptable rate of endothelial cell loss. Slit lamp, tomographic, and specular imaging over a four month period show a gradual course of wound healing that passes first through a bleb-like appearance until the surgical site seals in and heals with tensile strength for maintenance of physiologic intraocular pressure. Understanding this process can be helpful for clinicians guiding patients through their postoperative course.

Although Tenon patch grafting of corneal perforations has been described,¹⁰ we believe the addition of a separate overlying conjunctival flap containing a vascular pedicle represents an advancement over previous techniques. A flap of Tenon advanced from the limbus has been shown to have a flattening effect on the cornea,⁶ whereas a conjunctival pedicle introduces nutrients to facilitate rapid wound healing without inducing significant astigmatism. A previous report described using a conjunctival pedicle flap for closure of a limbal perforation, but our use of a separate Tenon patch graft allows for repair of larger, more central defects. In this case, surgically directing a conjunctival vascular supply to the patch graft appeared to promote rapid replacement of lost stromal tissue and complete fill-in of the perforation within 6 weeks. Vascular remodeling within the conjunctival flap appeared to correlate with the course of wound healing, with formation of a prominent conjunctival feeder vessel within 4 weeks and spontaneous regression of this vessel by 4 months as healing had completed. Combining Tenon patch grafting with a conjunctival flap may have resulted in much faster healing compared to prior reports of Tenon patch grafting for sterile perforations, which describe normalization corneal stromal thickness taking place over a longer time course of 15 months.¹¹

While fibrin glue can be a useful tool for sealing perforations and even securing Tenon fascia to the surface of the eye, it is not always readily available. In a case report of Tenon patch graft for corneal fistula, Maharana and colleagues secured Tenon with 4 radial non-absorbable nylon sutures creating a diamond-shaped patch, similar to our approach.¹² While this avoided the need for gluing, we also found it helpful to utilize polyglactin sutures that could be removed postoperatively when no longer needed, as in our technique, or left to resorb on their own depending on the individual patient’s healing course and ability to follow up.

Several features of this patient’s perforation made him an excellent candidate for the procedure. The perforation was non-central, meaning a procedure sparing the visual axis carried substantial advantages over more invasive interventions such as lamellar patch grafting or penetrating keratoplasty. The perforation was small enough to be patched closed without distorting the overall corneal contour beyond the perforation site, and after wound healing had completed and sutures had been gradually removed the patient had essentially no post-surgical astigmatism. Direct surgical closure of round defects typically induces far more surgical astigmatism. For infectious or autoimmune perforations, the underlying condition must be identified via timely diagnostic workup and aggressively treated to prevent worsening. The patient’s young age may have also increased likelihood of rapid vascularization and healing. Further studies of this technique in additional patients would help optimize patient selection and help compare long-term outcomes versus existing Tenon patch graft techniques.

This technique may also be beneficial for management of certain types of corneal trauma in resource-limited settings with limited access to eye banking and corneal tissue.¹³ Transplantation often requires steroids which can cause early cataract formation or intraocular pressure elevation and also carry direct and indirect costs for the medication itself. In such settings, a Tenon patch graft with conjunctival flap may be an effective, accessible, and affordable means of restoring tectonic integrity, preserving clarity of the visual axis, reducing surgically induced astigmatism, and reducing the need for postoperative steroids or keratoplasty.