Randomised Controlled Trial of Fluorescent Urography Using Intravenous Methylene Blue Compared to White Light Alone in Left-sided Colorectal Surgery

What Was Tested

This registered phase 4 trial tested Methylene blue (non-peptide stack partner).

This study will see if a blue dye (methylene blue) given into a vein, together with a special camera light, helps surgeons find the left ureter (the tube from the kidney to the bladder) faster during left-sided bowel surgery.

Adults having open, laparoscopic, or robotic left-sided colorectal surgery will be randomly assigned to either the blue dye with special light or standard white light alone.

The main question is whether the blue dye method finds the ureter more quickly, which could make the operation safer.

It had two arms (groups): Fluorescence Imaging with Intravenous Methylene Blue (experimental) and White Light Visualisation Alone (no intervention).

Fluorescence Imaging with Intravenous Methylene Blue.

White Light Visualisation Alone.

The registry classes the interventions as device and drug.

More on the Plan

This randomised controlled trial will test whether intravenous methylene blue, viewed with a special fluorescence camera, helps surgeons identify the left ureter (the tube that carries urine from the kidney to the bladder) more quickly during left-sided colorectal (bowel) surgery.

Ureter injury is a rare but serious complication, and in some patients the ureter is hard to see under standard white light.

The main outcome is the time from starting dissection to first seeing the left ureter.

The study will also record how often the ureter is seen at set time points, operating times, surgeon-rated ease and confidence, any changes to the surgical plan, complications, and ureteric injuries.

Who Took Part

The registry lists 108 planned participants were the target.

It was open to people of any sex aged from 18 years with no upper age limit.

Healthy volunteers were not accepted; participants needed the condition being studied.

Examples of who could join: Aged ≥18 years. Scheduled to undergo open, laparoscopic or robotic left-sided colorectal surgery, including left colectomy, high anterior resection, low anterior resection, abdominoperineal resection, subtotal colectomy and total colectomy.

The full record lists 2 inclusion and 7 exclusion criteria; among the exclusions: unable to understand the aims and objectives of this study and unable to give consent for participation; known allergy to methylene blue; taking selective serotonin reuptake inhibitors, serotonin and norepinephrine reuptake inhibitors, monoamine oxidase inhibitors, or tricyclic antidepressants (risk of serotonin syndrome).

How the Study Was Run

It was run as a randomized, parallel-group and open-label study.

Because people in this Methylene blue (non-peptide stack partner) study were split into groups at random, differences between the groups are less likely to reflect who happened to join each one.

Groups ran in parallel: each of the participants stayed in one arm throughout.

Being open-label, the Methylene blue (non-peptide stack partner) study did not mask who received what.

It started in 2026-10-01 with completion listed for 2028-10-01.

It ran at 1 site in Hong Kong.

Its stated primary purpose is treatment.

What Was Measured

The main thing measured (primary outcome): Time to identification of the left ureter (time frame: Intraoperative, from peritoneal incision until the ureter is first seen).

What This Means in Plain Language

Put simply, this is a phase 4, randomized trial of Methylene blue (non-peptide stack partner) in 108 people.

Its status is not yet recruiting; no results are posted to the registry yet, so nothing here describes outcomes.

More context: the Methylene blue (non-peptide stack partner) compound page, all human trials.