Preoperative subconjunctival combined injection of bevacizumab and mitomycin C before the surgical excision of primary pterygium: clinical and histological results

The aim of this study was to detect the clinical and histological effects of preoperative subconjunctival injection of both bevacizumab and mitomycin C (MMC) 1 month before the surgical excision of primary pterygium using a bare sclera technique. A total of 20 patients with primary pterygium underwent subconjunctival combined injection of 0.1 mL of MMC (0.1 mg/mL) and 0.1 mL of bevacizumab (1.25 mg/0.1 mL) 1 month before bare sclera excision of the pterygium. The excised pterygium tissues were examined histologically and immunohistologically by CD31 staining, and the patients were followed up clinically for at least 2 years. The excised pterygia of two patients without preoperative injection were used for histological comparison. Clinically, there were no intraoperative or postoperative complications. No recurrence was noted during the follow-up period. Histologically, the previously injected pterygia showed a decreased number of epithelial cells and stromal fibroblasts. The latter were rounded or oval and swollen rather than spindle shaped, and some were degenerating or apoptotic. Collagen and elastic fibers were degenerated, distorted, and decreased in density, while blood capillaries were obliterated. There was a significant decrease in CD31-positive cells in previously injected pterygia. Preoperative subpterygium combined injection of bevacizumab and MMC is safe and effective in reducing the postoperative recurrence of primary pterygium. Histological and immunohistological changes in the form of decreased fibrovascular activity and degeneration of the extracellular matrix and nerve axons were noted.