Fluorescence to highlight the urethra: a human cadaveric study

T G Barnes,R Hompes,M Penna,C Cunningham

doi:10.1007/s10151-017-1615-y

Abstract

BackgroundUrethral injury is a complication feared by surgeons performing transanal TME (TaTME) or abdominoperineal excision (APE) procedures. Injury during TaTME occurs when the prostate is inadvertently mobilised or as a direct injury similar to the direct injury during the perineal dissection of APE procedures. We performed a proof of principle study to assess the feasibility of using indocyanine green (ICG) to fluoresce the urethra in human cadavers.MethodsIndocyanine green at varying doses was mixed with Instillagel and infiltrated into the urethra of male human cadavers. The urethra was exposed through either a perineal incision or by mobilisation of the prostate during a TaTME dissection and fluorescence observed using a PINPOINT laparoscope (NOVADAQ). Brightness was assessed on the images using ImageJ (National Institute of Health).ResultsEight cadavers were included in the study. Fluorescence was visualised in the urethra in all eight cadavers. Minimal dissection was required to obtain fluorescence transperineally. In one cadaver, the urethra was demonstrated under fluorescence using a simulated TaTME with additional fluorescence also being observed in the prostate. There was no correlation between brightness and dosing.ConclusionsThis novel proof of principle study demonstrates a simple way in which the urethra may be easily identified preventing it from injury during surgery.

Highlights

Operative management of rectal cancer involves anterior resection in the form of a total mesorectal excision (TME) or, for low rectal cancers invading the sphincter muscles, abdominoperineal excision (APE) of the rectum is appropriate
Background Urethral injury is a complication feared by surgeons performing transanal TME (TaTME) or abdominoperineal excision (APE) procedures
We performed a proof of principle study to assess the feasibility of using indocyanine green (ICG) to fluoresce the urethra in human cadavers

Summary

Introduction

Operative management of rectal cancer involves anterior resection in the form of a total mesorectal excision (TME) or, for low rectal cancers invading the sphincter muscles, abdominoperineal excision (APE) of the rectum is appropriate. A recently developed procedure for TME dissection is to perform the procedure via a combined laparoscopic abdominal and endoscopic approach: transanal total mesorectal excision (TaTME). The injury occurs following inadvertent mobilisation of the prostate, putting the membranous urethra at risk [4]. This injury may be avoided with adequate training and mentoring in the technique. Direct injury can still occur without prostate mobilisation during perineal dissection in an intersphincteric approach or APE. Urethral injury is a complication feared by surgeons performing transanal TME (TaTME) or abdominoperineal excision (APE) procedures. Injury during TaTME occurs when the prostate is inadvertently mobilised or as a direct injury similar to the direct injury during the perineal dissection of APE procedures. We performed a proof of principle study to assess the feasibility of using indocyanine green (ICG) to fluoresce the urethra in human cadavers

Methods

Results

Conclusion