Noncontact Conjunctiva: A Better Mitomycin C Application Site for Trabeculectomy

INTRODUCTION

Bleb scarring is the most important complication of trabeculectomy. Changing the application position of mitomycin C (MMC) during trabeculectomy might affect the surgery outcome. Our aim is to compare the effectiveness and safety of intraocular pressure (IOP) lowering in two different application sites of mitomycin in trabeculectomy.

METHODS

This retrospective trial compared the surgical outcomes of 177 eyes that underwent trabeculectomy with adjunctive mitomycin C. In 70 eyes, an MMC-soaked sponge was applied under the scleral flap without touching Tenon's capsule. In 107 eyes, an MMC-soaked sponge was applied under the scleral flap covered by Tenon's capsule. Outcome measures were the IOP, best-corrected visual acuity (BCVA), success rates, and incidence of complications.

RESULTS

Within both groups, a highly significant IOP reduction was seen during follow-up. The effectiveness in reducing IOP and the change in best-corrected visual acuity (BCVA) were similar between the two groups. Thin-walled blebs and postoperative hypotony were seen more often when MMC-soaked sponges were applied under the scleral flap covered by Tenon's capsule (P = 0.008 and P = 0.012, respectively). There was no significant difference in BCVA or other complications in either group.

CONCLUSION

Since the effectiveness of IOP reduction was similar between both groups and with a low incidence of thin-walled blebs and hypotony, the subscleral application without touching Tenon's capsule seems to be the safer application site of MMC during trabeculectomy.

Treatment Outcomes of Mitomycin C-Augmented Trabeculectomy, Sub-Tenon Injection versus Soaked Sponges, after 3 Years of Follow-up: A Randomized Clinical Trial

PURPOSE

To report the 3-year outcome of trabeculectomy with mitomycin C (MMC)-soaked sponges versus intra-Tenon injection of MMC in eyes with uncontrolled primary open-angle glaucoma.

DESIGN

Randomized clinical trial.

PARTICIPANTS

Eighty-two consecutive patients with uncontrolled primary open-angle glaucoma.

METHODS

Participants were randomized either to intra-Tenon injection of 0.1 ml of 0.01% MMC (TI group) or 0.02% subconjunctival application of MMC-soaked sponges (TS group). Patients were followed up for 3 years after surgery. The data for 73 eyes were included in the final analysis.

MAIN OUTCOME MEASURES

The primary outcome measure was the surgical success, defined as intraocular pressure (IOP) more than 5 mmHg and <21 mmHg, and IOP reduction of 20% or more from baseline, no reoperation for glaucoma, and no loss of light perception vision. Secondary outcome measures were IOP, glaucoma medications, best-corrected visual acuity (VA), bleb morphologic features according to the Indiana Bleb Appearance Grading Scale, complications, and endothelial cell count changes.

RESULTS

The cumulative probability of success at 3-year follow-up was 72.2% in the TI group and 65.1% in the TS group (P = 0.30). Uncontrolled IOP was the most common reason for failure. The mean preoperative IOP was 22.4±4.6 mmHg with an average of 3.1±1.0 medications. At 3 years, final IOP was 15.3±3.7 mmHg in the TI group and 16.4±3.5 mmHg in the TS group (P = 0.55). Mean glaucoma number of medications was 0.9±1.1 and 1.1±1.1 in the TI and TS groups, respectively (P = 0.54). Blebs tended to be more diffuse (P = 0.032), less vascularized (P = 0.013), and more shallow (P = 0.012) after intra-Tenon injection. Visual outcomes and endothelial cell changes were similar in both groups (P = 0.47 and P = 0.94, respectively).

CONCLUSIONS

Although the success rate and IOP reduction were comparable with both techniques, bleb morphologic parameters were more favorable after intra-Tenon injection of 0.1 ml of 0.01% MMC.

Comparison of Superior Rectus and Peripheral Lamellar Corneal Traction Suture during Trabeculectomy

PURPOSE

To compare the efficacy and safety of two different traction suture (superior rectus traction suture and peripheral lamellar corneal traction suture) in patients undergoing trabeculectomy.

METHODS

This retrospective trial compared outcomes of 385 eyes that underwent trabeculectomy with superior rectus traction suture (SRTS group; 206 eyes; 53.3%) and peripheral lamellar corneal traction suture (CTS group; 179 eyes; 46.7%). Qualified surgical success is defined as an intraocular pressure (IOP) between 6 and 21 mm Hg with or without topical anti-glaucoma medication.

RESULTS

After a follow-up of 24 months, the difference of IOP was significant (p = 0.042). The mean number of anti-glaucoma medications was 3.5 ± 0.6 and 3.5 ± 0.5 preoperatively (p = 1.000), whereas 0.18 ± 0.32 and 0.10 ± 0.39 at 24 months (p = 0.028). The 24-month qualified surgical success rates were 88.3% and 94.4% for both groups (p = 0.035; log-rank test). The difference between the two groups in regard to maximal bleb area is statistically significant (p = 0.011), with CTS group exhibiting more diffuse bleb area. The difference between the two groups in regard to the vascularity at the central and peripheral part of bleb is statistically significant (p = 0.019; p = 0.023, respectively). Encysted blebs was seen in 27 (13.1%) eyes in SRTS group and in 12 (6.7%) eyes in CTS group (p = 0.041).

CONCLUSION

The use of superior rectus traction suture is significantly associated with a lower success rate than corneal traction suture, suggesting that surgeons should use a corneal fixation suture if at all possible.

Effect of different application depths of mitomycin-C in deep sclerectomy with collagen implant: a randomized controlled trial

PURPOSE

To evaluate effects of mitomycin-C (MMC) in deep sclerectomy with collagen implant applied under the superficial scleral flap or under the deep scleral flap.

METHODS

Twenty-five patients with primary or secondary open-angle glaucoma and at high risk for postoperative cicatrization underwent deep sclerectomy and were randomly distributed to the two treatment arms. In the superficial MMC group (S-MMC), MMC was applied under the superficial scleral flap using a soaked sponge for 60 s; in the deep MMC group (D-MMC), MMC was applied under the deep scleral flap for 60 s before entering the Schlemm's canal. In both groups, remaining MMC was irrigated with 40 mL balanced salt solution. Patients were followed up for up to 2 years. The volume of filtering blebs was studied with ultrasound biomicroscopy at the last follow-up visit.

RESULTS

Mean preoperative intraocular pressure (IOP) was 20.5 +/- 8.9 mmHg for D-MMC and 21.6 +/- 6.6 mmHg for S-MMC eyes (P = 0.67). The mean postoperative IOP was 5.3 +/- 3.3 mmHg (D-MMC) and 6.9 +/- 4.8 mmHg (S-MMC) at day 1 (P = 0.22) and 11.4 +/- 6.3 mmHg (D-MMC) versus 11.3 +/- 4.6 mmHg (S-MMC) at last follow up (P = 0. 54). The mean number of medications per patient was reduced from 2.5 +/- 0.5 to 0.4 +/- 0.5 (D-MMC) (P < 0.001) and from 2.5 +/- 0.9 to 0.3 +/- 0.4 (S-MMC) (P < 0.001). Ultrasound biomicroscopy at 24 months showed mean intrascleral space volume of 1.97 +/- 0.35 mm3 (D-MMC) and 5.68 +/-0.42 mm3 (S-MMC) (P < 0.05).

CONCLUSION

No significant difference in efficacy and safety was found between the two groups at a mean of 19.2 months of follow up. Deep scleral application of MMC, however, seems to produce significantly smaller intrascleral blebs.

Long-term results of trabeculectomy with mitomycin C applied under the scleral flap

PURPOSE

The objective of this study was to look at the long-term safety, and the effectiveness on intraocular pressure, of trabeculectomy and mitomycin C (MMC) applied under the scleral flap.

METHODS

All patients undergoing trabeculectomy and MMC application during the period June 1992-August 1995 were included. Data on 30 eyes of 25 patients were reviewed. We looked at sociodemographic variables, intraocular pressure (IOP) control, visual acuities and bleb morphology. Bleb-related and other complications were also noted. Statistical analysis was performed with Student's paired t-test, and Kaplan-Meier life table analysis was utilised for IOP control.

RESULTS

The mean age of patients (12 male and 13 female) was 56 years (range 7-79 years), with a mean follow-up period of 8.7 years (range 5-11 years). There was one eye with blebitis/endophthalmitis at 4 years, and one eye developed hypotonous maculopathy. Ten eyes were noted to have poor bleb morphology due to long-standing fibrosis, and the majority of these underwent further surgical intervention with 5-fluorouracil (5FU) needling. The IOP control showed good results, with mean IOP falling from a preoperative level of 24.8-15.2 mmHg at the last visit, with good probability of maintenance in the longer term. The main reason for reduced vision was pre-existing co-morbidity and development of lenticular opacities.

CONCLUSION

In the series with the longest follow-up period our study showed that trabeculectomy augmented with MMC under the scleral flap in these difficult cases can achieve good long-term IOP control and is associated with minimal long-term complications.

Long-term effects of simultaneous subconjunctival and subscleral mitomycin C application in repeat trabeculectomy

PURPOSE

To assess the efficacy and safety of simultaneous mitomycin C application under conjunctival and scleral flaps in patients with repeat trabeculectomy.

METHODS

A total of 44 patients (44 eyes) with previous failed filtering surgery were randomized to one of two groups. The both-flaps group comprised 22 patients (22 eyes) with trabeculectomy and intraoperative mitomycin C application under conjunctival and scleral flaps, whereas the subconjunctival group comprised 22 patients (22 eyes) with subconjunctival application of mitomycin C. Particular attention was paid to intraocular pressure, postoperative medications, visual acuity, filtering bleb appearance, and complications. The mean follow-up time was 38.18 +/- 12.48 months.

RESULTS

The mean preoperative intraocular pressure decreased from 39.1 +/- 7.3 mm Hg to the postoperative level of 15.6 +/- 4.8 mm Hg in the both-flaps group (P = 0.014), and from 39.4 +/- 8.4 to 18.7 +/- 5.8 mm Hg in the subconjunctival group (P = 0.018). There was a statistically significant difference in intraocular pressure at all follow-up times, except at 1 week and 1 month postoperatively. Kaplan-Meier survival analysis showed there was no significant difference in total success rate (complete plus qualified success) between the two groups (P = 0.622, log-rank test). However, the two survival curves for the complete success subgroups (without additional medications) confirmed that mitomycin C applications under both flaps had a higher success rate than subconjunctival application (P = 0.043, log-rank test). No statistically significant difference in medications was present between the two groups, and no severe complications developed in either group.

CONCLUSIONS

Trabeculectomy augmented with mitomycin C application at both sites could produce a greater lowering of intraocular pressure with low incidence of postoperative complications, and could provide an increased chance of long-term success. The procedure is effective and safe in patients with repeat trabeculectomy.