National survey of intraoperative mitomycin C use during trabeculectomy surgery in the UK

Abstract

Purpose

Mitomycin C is a routinely used antimetabolite which effectively limits the scarring process. Conventionally, the intra-operative technique of MMC delivery during trabeculectomy is the direct application of the soaked sponges. The aim of this study is to evaluate the current practice of delivering MMC during trabeculectomy and to see the practices related to a retained MMC swab during trabeculectomy in the UK.

Methods

An electronic questionnaire of 8 questions regarding the intraoperative use of MMC during trabeculectomy surgery was emailed to 69 ophthalmologist members of the UK and Eire glaucoma society (UKEGS) through email in July 2019.

Results

97.2% of the surveyed glaucoma surgeons said they use MMC during trabeculectomy routinely, while 2.9% said they never use MMC for trabeculectomy. In reply to a question ‘Have you ever had a retained MMC-soaked sponge/fragment of sponge’, 11.76% replied ‘yes’, 88.24% said ‘No’. In response to what technique was employed at the time of retained MMC sponges, all the respondents said they had employed the same technique of ‘multiple individual sponges’. 47.1% surgeons said they use multiple individual sponges on being asked what technique they currently employ for delivering MMC during trabeculectomy surgery, while 14.7% surgeons use multiple sponges linked with a ‘necklace suture’ and 5.9% inject MMC.

Conclusion

Our survey suggests the intra-operative MMC use in the UK is high and that unintentional MMC-soaked swab retention does occur, albeit rarely. A preference of using the MMC-soaked swabs as a delivery method of MMC is seen in our survey.

Appendix

• 1. How often do you use mitomycin C (MMC) in a trabeculectomy surgery?

i	Never	□
ii	Less than 25% cases	□
iii	Between 25–50% cases	□
Iv	More than half of the cases	□

If you have answered “Never”, then please DO NOT answer any other questions and click Finish Survey at the bottom of the page. In case of any other answers please continue to question 2 below:

• 2. Have you ever had a retained MMC-soaked sponge/fragment of sponge?

If you select "yes" please answer all remaining questions.

If you select "no" please go to question 6.

Y	□
N	□

• 3. What technique did you employ at the time?

Multiple individual sponges	□
Corneal light-shield cut in half/quarter	□
Multiple sponges linked with a ‘necklace’ suture	□
Others (please specify):	□

• 4. What sponge material did you use at the time?

Polyvinyl alcohol (PVA)	□
Methylcellulose	□
Absorbable gelatine sponges(AGS)	□
Other (please specify):	□

• 5. What size of sponge material did you use at the time?

1 × 1 mm	□
2 × 1 mm	□
3 × 1 mm	□
Others: (please specify)	□

• 6. What technique do you currently employ?

Multiple individual sponges	□
Corneal light-shield cut in half/quarter	□
Multiple sponges linked with a ‘necklace’ suture	□
Inject MMC subconjunctivally instead of using sponges	□
Other: (please specify if technique not described above)	□

• 7. What sponge material do you currently employ?

PVA	□
Methylcellulose	□
AGS	□
Other: (please specify)	□

• 8. What sponge size do you currently employ?

1 × 1 mm	□
2 × 1 mm	□
3 × 1 mm	□
Other: (please specify)	□