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Oral Riboflavin to Assess Ureteral Patency During Cystoscopy

A Randomized Clinical Trial

Stitely, Michael L., MD; Harlow, Keryn, MBChB; MacKenzie, Elliot, MBChB

doi: 10.1097/AOG.0000000000003063
Contents: Urogynecology: Original Research

OBJECTIVE: To evaluate whether oral riboflavin is more effective than placebo as a marker of ureteric patency at cystoscopy.

METHODS: Patients scheduled for gynecologic surgery where cystoscopy was a planned component of the procedure were randomized to receive riboflavin 400 mg or placebo orally the night before surgery. During cystoscopy, the operating surgeon visualized ureteric jets and video recorded the cystoscopy portion of the procedure. The primary outcome was to determine whether orally administered riboflavin produced stronger yellow color of urine seen on cystoscopy than placebo on a 3-point scale. Secondary outcomes were to assess whether riboflavin administration improved ease of identifying ureteric jets (5-point scale) and whether a greater proportion of patients had both ureteric jets visualized with riboflavin compared with placebo. A sample size of 33 per group was planned.

RESULTS: From June 28, 2017, to February 19, 2018, 72 women were screened and 66 were randomized, with 33 patients in each study group. The groups were similar in age, weight, body mass index, and ethnicity. The patients in the riboflavin group had significant increase of yellow-colored urine as rated by the operating surgeon, with a median of 2 compared with 1 on a 3-point scale (P<.001). The ureteral jets were more easily visualized in the riboflavin group as rated by the operating surgeon, with a median of 5 compared with 4 on a 5-point scale (P<.013). Bilateral ureteral patency was confirmed in 30 of 33 women (91%) in the riboflavin group and in 28 of 33 women (85%) in the placebo group (P=.71).

CONCLUSIONS: The administration of riboflavin before gynecologic surgery improves the ease of visualizing the ureteric jets by inducing yellow coloration of the urine.

CLINICAL TRIALS REGISTRATION: Australian New Zealand Clinical Trials Registry, 12616001367437.

Orally administered riboflavin increases the coloration of the urine and improves the visualization of the ureteric jets during intraoperative cystoscopy.

University of Otago, Dunedin School of Medicine, Dunedin, Obstetrics and Gynaecology, Canterbury District Health Board, Christchurch, and Obstetrics and Gynaecology, Southern District Health Board, Dunedin, New Zealand.

Corresponding author: Michael L. Stitely, MD, Department of Women’s and Children’s Health, Dunedin School of Medicine, PO Box 56, Dunedin 9054, New Zealand; email: Michael.Stitely@Otago.AC.NZ.

Supported by Healthcare Otago Charitable Trust and Australasian Gynaecological Endoscopy & Surgery Society.

Financial Disclosure The authors did not report any potential conflicts of interest.

Presented at the American Urogynecologic Society Pelvic Floor Disorders Week meeting, October 9–13, 2018, Chicago, Illinois.

Each author has confirmed compliance with the journal’s requirements for authorship.

Peer reviews and author correspondence are available at

Received September 19, 2018

Received in revised form October 29, 2018

Accepted November 01, 2018

© 2019 by The American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.