Success rate and complications of intraoperative 0.2 mg/ml Mitomycin C in trabeculectomy surgery

Abstract

Adjunctive chemotherapy with Mitomycin C (MMC) has been used in an attempt to modulate the wound healing response in glaucoma filtration surgery. A consecutive series of 20 eyes from 18 patients undergoing trabeculectomy with MMC intraoperatively was studied. Sixteen cases were considered high risk regarding surgical success and 4 patients with low tension glaucoma (LTG) required lower intraocular pressure (IOP) to prevent further visual field loss. Surgical technique involved the use of a limbal-based conjunctival flap and MMC 0.2 mg/ml applied via a sponge (under the scleral flap) to both scleral and conjunctival surfaces for 5 minutes. The mean follow-up period was 12.7 months (range 3-24). There were 17 successful eyes. Of these, 14 are high pressure glaucoma eyes with a mean pre-operative IOP of 30.9 +/- 10.9 mmHg and a mean postoperative IOP of 15.3 +/- 5.2 mmHg (p = 0.001). The remainder of the successful cases include 4 patients with LTG with a mean preoperative IOP of 17.8 +/- 0.5 mmHg and a mean postoperative IOP of 6.8 +/- 0.7 mmHg (p = 0.001). Serious complications included chronic repeated bleb leaks (n = 2) and scleral necrosis (n = 2). There was one case of hypotonous maculopathy. These results are comparable with those of other studies. Despite a relatively low dose of MMC serious side-effects were encountered. Management of these complications is described, and how these effects may be prevented by altering scleral exposure to MMC. In addition a possible explanation for the serious side-effects of MMC-treated trabeculectomies is presented.

Modification of trabeculectomy with single‐dose intraoperative 5‐Fluorouracil application

“…Lower IOPs and better IOP control has been reported in the MMC-treated eyes in randomized, comparative studies (Kitazawa et al 1991;Skuta et al 1992;Katz et al 1995). However, caution needs to be exercised when using MMC because serious complications such as hypotonic maculopathy, scleral ulceration and chronic, recurrent bleb leaks have been reported with its use on the eye (Skuta et al 1992;Katz et al 1995;Singh et al 1995;Kupin et al 1995). Lower concentrations (0.2 mg/ ml) or shorter exposure times (2 minutes) to MMC do not appear to eliminate complications entirely (Kitazawa et al 1991;Singh et al 1995).…”

“…Low dose intraoperative MMC has been considered as an alternative to subconjunctival 5 FU (Kitazawa et al 1991;Singh et al 1995;Lamping 1995). Lower IOPs and better IOP control has been reported in the MMC-treated eyes in randomized, comparative studies (Kitazawa et al 1991;Skuta et al 1992;Katz et al 1995).…”

“…However, caution needs to be exercised when using MMC because serious complications such as hypotonic maculopathy, scleral ulceration and chronic, recurrent bleb leaks have been reported with its use on the eye (Skuta et al 1992;Katz et al 1995;Singh et al 1995;Kupin et al 1995). Lower concentrations (0.2 mg/ ml) or shorter exposure times (2 minutes) to MMC do not appear to eliminate complications entirely (Kitazawa et al 1991;Singh et al 1995). have shown in their experimental studies that subconjunctival and scleral fibroblasts recover within thirty days after treatment with 5 FU (50 mg/ml), but not with Mitomycin C (0.4 mg/ml).…”

“…Intraoperative application of MMC results in lower pressures and higher success rates of trabeculectomy than postoperative subconjunctival 5 FU injections in high-risk eyes (Kitazawa et al 1991;Skuta et al 1992; Katz et al 1995). However, the resultant blebs are extremely thin-walled and avascular and serious complications such as persistent bleb leaks, hypotony with maculopathy and scleral ulceration have been reported with MMC use (Kitazawa et al 1991;Skuta et al 1992;Singh et al 1995;Kupin et al 1995).…”

A review of trabeculectomies at a Nigerian teaching Hospital

“…10,11 Adjunctive use of antifibrotic agents such as mitomycin C or 5-fluorouracil at the site of surgery has significantly reduced the risk of bleb failure. 12,13 Filtering procedures are associated with failures in the blacks owing to their propensity for increased fibrosis. Reports of favorable results are those from modifications of standard techniques such as non-suturing of flaps, sclerectomy, posterior lip cautery, or administration of high doses of steroids.…”