Historical Review
Conjunctival procedures include a bridge conjunctival flap (Gundersen flap), pterygium surgery, conjunctival excision for conjunctivochalasis, limbal stem cell transplantation (see Chapter 4.30 ), and tumor removal. In a conjunctival flap procedure, a hinged flap of conjunctiva is created to cover an unstable or painful corneal surface. Conjunctival flaps, partial or total, have remained an effective procedure over the past 100 years for the treatment of challenging ocular surface disorders in patients with poor visual prognosis.
Pterygium surgery dates back to 1855, when Desmarres first performed a transposition of the pterygium head. In 1872, Arlt recognized the importance of covering the epibulbar defect after pterygium excision and described the first conjunctival graft.
Specific Techniques
Conjunctival Flap
Preoperative Evaluation and Diagnostic Approach
Common indications for conjunctival flap include the following:
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Nonhealing sterile corneal ulcerations secondary to chemical or thermal injuries, herpetic infections, exposure keratopathies, and other neurotrophic diseases that are unresponsive to medical treatment.
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Painful bullous keratopathy or other chronically inflamed ocular surface disorders in eyes with low visual potential, in which penetrating or selective keratoplasty is not indicated; and in which simpler management techniques, such as soft contact lenses or anterior stromal puncture, have failed.
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Necrotizing scleritis resulting in severe melt that is unresponsive to systemic anti-inflammatory treatments, requiring tectonic support.
- •
Blind eyes in need of surface preparation for prosthetic shells or cosmetic contact lenses.
Relative contraindications for conjunctival flap include active infectious keratitis and corneal perforation in eyes with good visual potential.
Surgical Techniques
The availability of mobile conjunctiva is evaluated. Typically, the superior bulbar conjunctiva offers increased tissue availability. The corneal epithelium is mechanically debrided using a No. 64 blade or a cellulose sponge. Application of lidocaine 4% or absolute alcohol may assist in loosening the corneal epithelium. A 360° limbal peritomy is then performed ( Fig. 4.28.1 ).
The globe is rotated inferiorly from the donor site using a traction suture placed at the limbus to increase superior exposure. A semicircular incision, parallel to the corneal limbus, is made as posteriorly as possible. The dissection of a thin conjunctival flap is carried anteriorly until the corneal limbus is reached. Adequate dissection and undermining of this flap laterally is important for the subsequent anterior mobilization of the flap over the cornea and to prevent traction. The conjunctival flap is freed completely from its underlying Tenon’s capsule.
The well-mobilized conjunctival flap then is stretched to cover the desired area ( Fig. 4.28.2 ). The superior and inferior aspects of the flap are secured on the sclera using interrupted or running 10-0 nylon sutures. The edges of the conjunctiva may be reapposed with 7-0 or 8-0 Vicryl suture in a running fashion ( Fig. 4.28.3 ). Alternatively, fibrin glue has been shown to be a viable option for Gundersen flap surgery, with the possible advantage of reduced surgical and recovery time.
A partial conjunctival flap is used in certain circumstances, such as for focal nonhealing corneal ulcers that do not require coverage of the entire cornea. The procedure includes scraping of the corneal epithelium, mobilization of the conjunctiva in the appropriate quadrant, and suturing of the conjunctival flap over the localized corneal defect (see Fig. 4.28.3 ).
A total Tenon–conjunctival flap (TCF) has been used to increase corneal thickness in mildly phthisical eyes in preparation for prosthetic scleral shells. A modified Gundersen flap with the use of amniotic membrane transplantation has been reported in a small series of patients as a promising technique.
Complications and Postoperative Management
The most common perioperative complication is the creation of a conjunctival buttonhole during dissection. Buttonholes should be closed by using running or interrupted sutures. Postoperative complications include retraction of the conjunctival flap, hemorrhagic and epithelial mucous cysts, flap loss from epithelial ingrowth, ptosis, and progression or recurrence of inflammation or infection, such as that caused by herpes simplex virus.
After healing, a cosmetic contact lens may be fitted. In some cases, penetrating keratoplasty is indicated for visual rehabilitation. Because a conjunctival flap may have destroyed corneal limbal stem cells, a limbal allograft may be considered prior to penetrating keratoplasty.
Pterygium Surgery
Pterygium, most commonly seen at the nasal limbus, is a conjunctival fibrovascular growth over the sclera and onto the cornea (see Chapter 4.9 for more information).
Preoperative Evaluation and Diagnostic Approach
Surgical indications for excision of the pterygium include the following:
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Growth of pterygium such that it has impinged on or is imminently threatening the visual axis.
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Reduced vision as a result of induced astigmatism.
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Severe irritation not relieved by medical therapy.
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Surgery for unacceptable cosmetic appearance.
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Reduced motility secondary to pterygium.
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Recurrence, with more aggressive growth than in primary lesions.
Surgical Techniques
Several techniques have been described including bare sclera technique, conjunctival autograft placement, amniotic membrane transplantation, antimetabolites, radiation, and, in cases of severe recurrence, mucous membrane grafts.
Bare Sclera Technique/Simple Closure
Although technically simple, this technique can be associated with recurrence rates as high as 40%. Surgically, the lesion may be outlined using spot cautery or a sterile marker. To facilitate dissection, the eye may be rotated laterally using traction sutures (6-0 Vicryl or silk) placed at the superior and inferior corneal limbus. The dissection may be initiated at the corneal side of the pterygium. Using forceps, the head of the pterygium is lifted and dissected off the cornea in a lamellar fashion using sharp dissection with a blade ( Fig. 4.28.4 ). Alternatively, the scleral portion may be removed first, followed by blunt dissection or avulsion of the corneal portion. The scleral part of the pterygium is excised by using scissors ( Fig. 4.28.5 ). Care is taken to identify the underlying rectus muscle, especially in surgery for recurrent pterygium. The corneal defect may be polished by using a diamond burr. Antimitotic agents, such as mitomycin-C (MMC) 0.02%, have been used to prevent recurrence in conjunction with this technique. Care should be taken to avoid excessive contact of MMC with the sclera. Instead of leaving the sclera bare, the conjunctiva can be closed with 7-0 or 8-0 Vicryl suture, although the recurrence rates have not been shown to be significantly reduced with primary closure.
Autograft
Conjunctival autografting is considered the “gold standard” for pterygium surgery because of its low rate of recurrence (rates reported as low as 5% in primary cases) and excellent cosmesis. After pterygium excision, the size of the defect is measured. Commonly, in a nasal pterygium, the superotemporal bulbar conjunctiva is used as the donor site. Tractional sutures may be used to rotate the eye downward. The donor conjunctiva is outlined using spot cautery or a sterile marker and a thin Tenon’s free conjunctival flap is dissected with forceps and scissors ( Fig. 4.28.6 ). It is important to avoid buttonholes and to maintain limbus-to-limbus orientation of the conjunctival flap when transferring the flap to the recipient bed to ensure proper positioning of limbal stem cells. Alternatively, the conjunctival flap may be rotated on a pedicle. The graft is then secured using Vicryl or 10-0 nylon sutures ( Fig. 4.28.7 ), or fibrin glue.
Amniotic Membrane
Amniotic membrane transplantation (AMT) has been implemented as an alternative to conjunctival autografting despite its higher cost. Amniotic membranes are secured using similar techniques as conjunctival autografts and are especially amenable to the use of fibrin glue. The amniotic membrane is placed stromal side adjacent to the scleral bed. Benefits include shortened operative time and untouched conjunctiva for future use, such as in glaucoma surgery. However, in a prospective study (mean follow-up, 11 months) comparing AMT to conjunctival autografts, AMT had higher recurrence rates for primary (10.9% versus 2.6%), recurrent (37.5% versus 9.1%), and all pterygia (14.8% versus 4.9%) compared with conjunctival autografts, respectively. These results establish the use of conjunctival autografting as the procedure of choice for pterygium surgery unless a conjunctival preserving technique is indicated.
Other Techniques.
Several, more recent techniques have been described to have success in preventing pterygium recurrence after excision. Limbal conjunctival autograft (LCAU), in which a free conjunctival graft is harvested to include the superficial limbus, has been demonstrated to have a low recurrence rate (6.9%) after 10 years of follow-up. Minor ipsilateral simple limbal epithelial transplantation (mini-SLET), which utilizes amniotic membrane and the placement of limbal epithelial pieces, has been described in the treatment of 10 eyes without recurrence after 8 months of follow-up.
Recurrent Pterygium Excision.
Excision of recurrent pterygia can be especially tedious even for the experienced surgeon because of extensive fibrosis of the pterygium to the sclera and cornea, distortion of tissue planes and normal anatomy, and symblepharon formation. The rectus muscle should be isolated in cases of scarring of the muscle sheath prior to dissection, and all symblepharon must be released to alleviate any motility restriction.
Antimetabolites and Radiation
MMC has been used preoperatively, intraoperatively, and postoperatively in pterygium surgery and appears to reduce the recurrence rates (particularly if amniotic membrane is used). Antimetabolites, however, have been associated with serious complications, including corneal or scleral melts. Thus, MMC should be used judiciously in cases with a high likelihood of recurrence. In addition, beta radiation using strontium-90 has been employed and shown to reduce recurrence; however, it may cause significant complications such as scleral necrosis, cataract, and persistent epithelial defects ( Fig. 4.28.8 ). Beta radiation after pterygium surgery has been supplanted largely by conjunctival or amniotic membrane transplantation.
Fibrin Glue
Fibrin glue is a two-component tissue adhesive that is used in many surgical procedures. One component consists of a protein fibrinogen solution, and the other consists of a thrombin solution. When mixed together, a fibrin clot is formed. Several studies have shown that the use of fibrin glue decreases postoperative pain and foreign body sensation and leads to reduced operative time and blood loss during surgery. It is being used with increasing frequency with both conjunctival autografts and amniotic membranes. Additionally, fibrin glue eliminates or reduces the number of sutures required. In a recent study, comparing Vicryl sutures to two of the most commonly used fibrin glues worldwide, Tisseel (Baxter Corp., Deerfield, IL) and Evicel glue (Omrix Biopharmaceuticals Ltd., Ramat-Gan, Israel), Tisseel glue was found to be superior with regard to pterygium recurrence, patient comfort, and surgical time. Patients must understand that this is an off-label use for fibrin glue. Patients also need to give their consent for blood product use because fibrin glue is derived from pooled human blood. However, it has been used for many years in thousands of surgeries with no documented cases of transmission of hepatitis B or C, human immunodeficiency virus (HIV) infection, or prion-mediated disease. Furthermore, donated plasma undergoes viral polymerase chain reaction screening prior to use.
Complications and Postoperative Management
Complications of pterygium surgery include recurrence of the pterygium, conjunctival granuloma, subconjunctival hemorrhage, corneoscleral dellen, epithelial inclusion cysts, graft retraction or necrosis, corneal or scleral melt with the use of antimetabolites or beta radiation, and conjunctival fibrosis. Topical antibiotics and corticosteroids are prescribed after surgery. Topical corticosteroids generally are used for 1–2 months postoperatively to minimize resultant inflammation.
Conjunctivochalasis Management
Conjunctivochalasis is a loosely adherent, redundant conjunctiva more commonly found overlying the inferior bulbar surface, typically in older individuals or those with a history of chronic inflammation. Although often asymptomatic, it may interfere with normal tear flow, lubrication of the ocular surface, and cause local exposure and associated irritation or pain. Additionally, if prominent nasally, the redundant conjunctiva may occlude the lower punctum, resulting in epiphora. In patients with significant symptoms uncontrolled with topical medications, such as artificial tears and topical corticosteroids, conjunctival cautery and surgical excision have been proposed as treatment modalities. These options must be approached judiciously, as the condition is likely to recur. Simple cauterization of the conjunctiva is usually performed in the office after topical gel anesthetic is applied using smooth forceps to grasp the excess inferior conjunctiva several millimeters from the limbus, which is then cauterized ( Fig. 4.28.9 ). Additional options include conjunctival resection ( Fig. 4.28.10 ) and scleral fixation of the conjunctiva. Surgical consideration should be given only when conservative treatment modalities are insufficient in providing adequate relief.
Surgical Techniques
After topical anesthesia is instilled, smooth forceps are used to grasp the excess inferior conjunctiva approximately 5 mm from the limbus, which is then marked with a marking pen. Using Wescott scissors and smooth forceps, the marked crescent of conjunctival tissue is then excised (see Fig. 4.28.10 ). Vicryl sutures are then used for simple closure of the conjunctiva, or an amniotic membrane transplant can be sutured or glued over the defect.
Complications
Recurrence of conjunctivochalasis after simple cautery or even excision should be discussed with the patient prior to the procedure. Other complications that may arise after conjunctival excision include conjunctival fibrosis, subconjunctival hemorrhage, granuloma formation, and cicatricial entropion.
Conjunctival Flap
Preoperative Evaluation and Diagnostic Approach
Common indications for conjunctival flap include the following:
- •
Nonhealing sterile corneal ulcerations secondary to chemical or thermal injuries, herpetic infections, exposure keratopathies, and other neurotrophic diseases that are unresponsive to medical treatment.
- •
Painful bullous keratopathy or other chronically inflamed ocular surface disorders in eyes with low visual potential, in which penetrating or selective keratoplasty is not indicated; and in which simpler management techniques, such as soft contact lenses or anterior stromal puncture, have failed.
- •
Necrotizing scleritis resulting in severe melt that is unresponsive to systemic anti-inflammatory treatments, requiring tectonic support.
- •
Blind eyes in need of surface preparation for prosthetic shells or cosmetic contact lenses.
Relative contraindications for conjunctival flap include active infectious keratitis and corneal perforation in eyes with good visual potential.
Surgical Techniques
The availability of mobile conjunctiva is evaluated. Typically, the superior bulbar conjunctiva offers increased tissue availability. The corneal epithelium is mechanically debrided using a No. 64 blade or a cellulose sponge. Application of lidocaine 4% or absolute alcohol may assist in loosening the corneal epithelium. A 360° limbal peritomy is then performed ( Fig. 4.28.1 ).
The globe is rotated inferiorly from the donor site using a traction suture placed at the limbus to increase superior exposure. A semicircular incision, parallel to the corneal limbus, is made as posteriorly as possible. The dissection of a thin conjunctival flap is carried anteriorly until the corneal limbus is reached. Adequate dissection and undermining of this flap laterally is important for the subsequent anterior mobilization of the flap over the cornea and to prevent traction. The conjunctival flap is freed completely from its underlying Tenon’s capsule.
The well-mobilized conjunctival flap then is stretched to cover the desired area ( Fig. 4.28.2 ). The superior and inferior aspects of the flap are secured on the sclera using interrupted or running 10-0 nylon sutures. The edges of the conjunctiva may be reapposed with 7-0 or 8-0 Vicryl suture in a running fashion ( Fig. 4.28.3 ). Alternatively, fibrin glue has been shown to be a viable option for Gundersen flap surgery, with the possible advantage of reduced surgical and recovery time.
