Title : Pitfalls in colonoscopy: A rare endoscopic never event identified through histopathological discordance
Abstract:
Introduction: Colonoscopy is a routinely used diagnostic and therapeutic tool and is considered the gold standard investigation for assessment of colorectal pathology. Whilst colonoscopy can lead to rare but serious complications, incorrect vaginal intubation during these are exceptionally rare. We present a case in which inadvertent vaginal intubation during colonoscopy was identified following unexpected histopathological findings, highlighting the importance of human factors and non-technical skills (NTS) in endoscopic practice.
Case presentation: A 35-year-old woman presented with a five-month history of altered bowel habit, intermittent rectal bleeding and lower abdominal pain, initially suspected to be consistent with irritable bowel syndrome. A colonoscopy was arranged to exclude other inflammatory or structural gastrointestinal pathologies. The procedure was performed under conscious sedation following standard bowel preparation.
During procedure, advancement of the scope was limited by apparent significant rectal stenosis and associated mucosal swelling, with the tissue appearing firm in consistency and lipoma-like in appearance. Histopathological analysis unexpectedly demonstrated squamous epithelium, with no identifiable colonic mucosa. In view of this, repeat laboratory verification to exclude specimen transposition was undertaken. Consequently, it was determined that the endoscope had been inadvertently introduced into the vagina, and subsequently a view of the cervix rather than the rectum had been obtained. A duty of candour was undertaken by the endoscopist following recognition of this error.
Discussion: Incorrect anatomical intubation during colonoscopy represents an extremely rare but serious “never event”. This case highlights how procedures seemingly routine for even the most experienced clinicians remain vulnerable to human factors, including potential loss of situational awareness and procedural complacency. Although there is intuitive tendency for endoscopists to focus on their technical abilities, NTS must be acknowledged as fundamental to safe practice. Human factors and non-technical skills are increasingly recognised as major contributors to endoscopic safety, reflected by the development of national frameworks such as Endoscopic Non-technical Skills (ENTS) and national safety initiatives from the Joint Advisory Group for Gastrointestinal Endoscopy (JAG) and NHS England. Other factors that could lead to this error were considered, including large patient body habitus, congenital cloacal abnormalities and technical difficulties related to positioning of the patient. In this case, it is theorised that procedural error occurred following dimming of lighting before confirmation of correct anatomical placement of the scope. In response, the Trust introduced a standard operating procedure (SOP) to prevent any recurrence of this event.
Conclusion: Inadvertent vaginal intubation during colonoscopy is an extremely rare but significant patient safety event. This case highlights the importance of maintaining procedural vigilance during routine endoscopic practice. As such, emphasis should continue to remain on NTS across all levels of clinical endoscopic practice to minimise potential errors.
