Feasibility Trial for Real-time Identification of the Ureters With a Methylene-blue

A Non-Randomized, Prospective, Open Label, Single-site Feasibility Trial for Real-time Identification of the Ureters With a Methylene-blue fluoroPhore

This is a non-randomized prospective, open label, single site study to evaluate the feasibility of recruitment for the use of an Investigational Endoscopic Fluorescence Imaging System, PINPOINT, in intraoperative bilateral visualization of ureters using intravenous injection of methylene blue. Feasibility of urine sample collection during surgery will also be assessed.

Background - During certain abdominal surgeries there is difficulty in finding the ureters, which act as a conduit for urine from the kidneys to the bladder. If the ureters are sectioned during surgery this causes great suffering for the patient and increased costs for the hospital and the National Health Service. Even experienced surgeons are at risk of causing this dreaded complication.

Methylene blue can emit a fluorescent signal and highlight the ureters in real time during surgical procedures. A study is necessary to evaluate the effectiveness of methylene blue fluorescence to identify the ureters during surgery.

Methods - In this study, patients undergoing abdominal surgery with high risk for ureter complications will be included. The feasibility of recruitment of these patients will be assessed using a screening log. Included patients with receive intraoperative methylene blue injection in increasing doses. Urine samples will be taken to establish the conversion of methylene blue to leucomethylene blue.

Expected results - the investigators expect to define the recruitment rate of the patient group of interest and to identify the causes for non recruitment. Secondary outcomes are ureteric identification and conversion of methylene blue to leucomethylene blue.

Inclusion Criteria:

• 18 years of age or older
• Scheduled for a surgery where routine ureter identification is used
• Have signed an approved informed consent form for the study
• Be willing and able to comply with the study protocol

Exclusion Criteria:

• Known allergy or history of adverse reaction to methylene blue
• Taking an antidepressant including, but not limited, to selective and non-selective serotonin reuptake inhibitors, or a psychiatric medication
• Glucose-6-phosphate dehydrogenase (G6PD) deficiency
• Renal dysfunction defined as estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m2
• Has participated in another investigational study within 30 days prior to surgery
• Pregnant or lactating subjects
• Subjects who, in the Investigator's and/or designee's opinion, have any medical condition that makes the subject a poor candidate for the investigational procedure, or interferes with the interpretation of study results