Complications after Pterygium Excision
The complications in pterygium surgery can be classified as intraoperative, early postoperative, and late postoperative.
13.2.1 Intraoperative Complications
13.2.1.1 Hemorrhage
Excessive bleeding can occur in highly vascularized thick pterygium. Identifying the bleeder and doing meticulous cautery on the blood vessel can reduce the incidence. Avoid holding the fleshy part of the pterygium with traumatic toothed forceps directly on the blood vessel. Hemorrhage can also happen in inflamed pterygium; therefore, inflamed pterygium has to be controlled by anti-inflammatory agents or low potent steroid before surgery. Hemorrhage can occur from the scleral bed after excision of the pterygium, and this has to be controlled by good cautious diathermy.
13.2.1.2 Scleral Lamella Removal
While excising the pterygium, the surgeon can inadvertently excise the underlying scleral lamella also. If the excised layer is thin, it will not cause significant problems postoperatively. However, if the depth of lamella is more, there can be scleral thinning and uveal exposure later. Hence, we recommend intraoperative visualization of the base and the posterior surface of the pterygium during excision.
13.2.1.3 Excess Cautery of Sclera
In case of excessive bleeding which obscures the visibility, the surgeon may cauterize the sclera along with the blood vessel. This may lead to scleral thinning and perforation. Hence, it is always required to visualize the zone of cautery and to utilize minimal power.
13.2.1.4 Corneal Damage
While doing the lamellar dissection of the pterygium on the corneal surface, the crescent blade can go deeper and cause disruption of normal corneal uninvolved stroma. This can rarely cause perforation and corneal scarring postoperatively. Hence, surgeons should take precaution not to dissect deeper, and a preoperative anterior segment optical coherence tomography can aid in such situation to determine the depth of dissection.
13.2.2 Immediate Postoperative Complications
13.2.2.1 Reactionary Hemorrhage
Reactionary hemorrhage occurs in the postoperative period due to dislodge of clot in the blood vessel, which induces it to rebleed spontaneously (▶ Fig. 13.1). Pressure bandage usually controls it. Patients with systemic hypertension should continue their antihypertensive medications to prevent rebleed.
Fig. 13.1 Hemorrhage below the amniotic membrane graft in the immediate postoperative period.
13.2.2.2 Conjunctival Chemosis
Conjunctival chemosis can be seen in few patients which resolves spontaneously.
13.2.2.3 Conjunctival Graft Edema
Graft edema may be seen in the early postoperative period; however, it resolves with topical treatment.
13.2.2.4 Conjunctival Recession
The conjunctiva may recede in the early postoperative period and expose the underlying sclera (▶ Fig. 13.2). This can occur due to tight conjunctival suturing or inadequate conjunctival closure. If the exposed region is more and there is scleral thinning, it will require repeat conjunctival closure by autograft or amniotic membrane graft.
Fig. 13.2 Conjunctiva receded in the immediate postoperative period.
13.2.2.5 Graft Reversal
Conjunctival autograft or amniotic membrane graft can turn or give way from the scleral bed with one end of the graft hanging (▶ Fig. 13.3). This can happen when the conjunctiva has not been properly adhered with fibrin glue, or if the sutures are loose. The possible reasons for the poor adhesion are due to improper application of tissue glue or sutures. The patient should be taken again to OR, for repositioning of the graft to be performed.
Fig. 13.3 Amniotic membrane graft slipped from the underlying sclera surface in the immediate postoperative period.
13.2.2.6 Hematoma
Hematoma below the graft may occur due to persistent bleeding because of improper hemostasis. In this case, the graft is examined under microscope, and hematoma is evacuated under block.
13.2.2.7 Localized Epithelial Defect
The localized epithelial defect is seen in almost all patients on day 1 of postoperative period, which heals within 24 hours.
13.2.2.8 Corneal Scar
Corneal scar, either a macular or nebular opacity, depending upon the depth of corneal involvement may be observed from the immediate postoperative period. Excess scar or deep opacity may require lamellar keratoplasty later.
13.3 Late Complications
13.3.1 Recurrence
One of the major limitations of pterygium excision is the high rate of postoperative recurrence. The recurrence time ranges from months to years. Increased fibroblastic activity is a well-established finding in recurrent pterygia. Recurrent pterygium is more difficult to treat than primary pterygium because it is often accompanied by increased conjunctival inflammation and accelerated corneal involvement. Partial limbal stem cell deficiency and coexisting inflammation might be one of the etiologies for recurrent pterygia. The recurrence rate was 10.9% (primary), 37.5% (recurrence), and 14.8% (all pterygium) after pterygium excision with amniotic membrane graft in a study by Prabhasawat et al. 1 Conjunctival autograft showed a recurrence of 2.6% (primary), 9.1% (recurrence), and 4.9% (all pterygium).
13.3.2 Treatment
Intraoperative use of antimetabolites, namely mitomycin C (MMC), reduces the risk of recurrence. 2,3,4 Lee et al has reported that MMC effects are stronger in recurrent pterygium than those with primary cells. 5 Conjunctival autograft with pterygium excision is known to show less recurrence and is the first choice of surgical treatment. 1,6 Amniotic membrane is a good alternate choice to reduce recurrence in advanced cases with bilateral heads or in patients who might need glaucoma surgery later. 6 The postoperative instillation of MMC 0.02% (0.2 mg/mL) eye drops twice daily for 5 days following excision of primary pterygium has been used to reduce recurrence. 7 Topical bevacizumab (5 mg/mL) twice a day has shown to delay the recurrence in impending recurrent pterygia. 8 Single-dose beta-irradiation after bare sclera surgery in the postoperative period is a simple, effective, and safe treatment that reduces the risk of primary pterygium recurrence. An Sr-90 eye applicator is used to deliver 2500 cGy to the sclera surface at a dose rate of between 200 and 250 cGy/min. 9
13.3.3 Complications Due to Use of Mitomycin C
13.3.3.1 Topical
MMC is an antimetabolite agent produced by a strain of Streptomyces caespitosus. It inhibits synthesis of deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and proteins. This drug is referred to as “radio-mimetic” as its action mimics that of ionizing radiation. Topical 0.02% eye drops have been known to cause ocular complications, such as superficial punctate keratitis, avascularized sclera, and pyogenic granuloma. Ocular discomfort and lacrimation are some of the common complaints. MMC 0.5 mg/mL has also been used after pterygium excision and beta-irradiation, which leads to complications such as scleromalacia, scleral ulcer, and cataract. 10
13.3.3.2 Intraoperative Mitomycin C
Scleral dellen is an early postoperative complication of bare sclera technique with MMC owing to delayed conjunctival wound closure. 11 Treated sclera may become white or “porcelainized” due to destroyed vessels and remain so forever. It has been reported that it is due to the drug’s effect on multipotential cells and the rapidly proliferating cells of vascular endothelium. 12 Complications including temporary and prolonged discomfort, tearing, hyperemia, subconjunctival hemorrhage, wound dehiscence, and pigment accumulation were also noted with a single dose of intraoperative MMC by Anduze and Burnett. 13 Hence, it is recommended that only high-risk pterygia should receive MMC. Conjunctiva should cover the sclera up to the limbus and thereby preventing migration of MMC. They concluded that a single dose of 0.5 mg/mL subconjunctivally gives the same results as multiple drops do, but with far less morbidity.
13.3.4 Suture-Related Inflammation
Suture-related inflammation is commonly seen with polyglactin sutures. Proper postoperative antibiotic applications can reduce it. Some surgeons prefer to use monofilament nylon for suturing the autograft due to an increase in inflammation with Vicryl sutures.
13.3.5 Tenon’s Cyst
This can occur in eyes in which the Tenon’s layer was exposed. Excision of the cyst with complete closure is recommended. Improper conjunctival autograft separation, in which the conjunctiva is harvested with thick Tenon’s layer, may be a risk factor for such complication.
13.3.6 Diplopia and Squint
Scarring and excessive fibrosis in region of pterygium or in the conjunctiva can lead to restriction of extraocular movements and diplopia. The patients with tendencies for keloid formation and hypertrophic scar are at high risk of developing such complication. Excess scarring can occasionally cause restrictive strabismus. In such cases, scar exploration and release of fibrosis are usually performed.
13.3.7 Scleral Complications
Scleral ulceration was present in 51 eyes on a long-term follow-up by Tarr and Constable. 14 Scleral thinning with perforation can also happen as a late complication. Excessive cautery to the scleral bed should be avoided as it can induce scleral thinning (▶ Fig. 13.4). Overenthusiastic use of antimetabolites can lead to scleral complications. Pseudomonas endophthalmitis occurred in four patients with scleral ulceration. 15 He observed that beta irradiation to prevent recurrence of pterygia is a significant cause of iatrogenic ocular disease. Patients with scleral thinning can be put on copious lubricants to improve ocular surface healing. Nonhealing scleral thinning and impending scleral perforation will require patch graft or amniotic membrane graft.
Fig. 13.4 Scleral thinning after pterygium surgery.
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