Colonoscopy is a commonly used investigation to diagnose and treat various gastrointestinal disorders. In addition, colonoscopy provides the opportunity to remove colonic adenomas this removal is also known as polypectomy.

Polypectomy has proven to reduce occurrence of colorectal cancer and likelihood of dying from it. Colonoscopy can be challenging due to technical or patient factors. In a small proportion of patients a complete colonoscopy is unsuccessful. Such patients either get referred to a tertiary centre with extensive experience in difficult colonoscopy or have an alternative test such as CT scan. The investigators unit has accumulated significant experience related to previously failed colonoscopy and anecdotally appears to have a high success rate in completing the procedure.

The purpose of this project is to describe the investigators technical approach to management of patients with previously failed colonoscopy. There is no additional intervention and the project is observational in nature. The investigators will collect data on patient characteristics, the reason for the failure and what technique was used to overcome the difficulty. The investigators will also note whether the final outcome of the technique had any impact on the overall management of the patient.

Inclusion Criteria:

• Previously failed colonoscopy
• Referred to Westmead Endoscopy Unit for a complete colonoscopy
• 18 years or older

Exclusion Criteria:

• Younger than 18 years
• Previously successful colonoscopy
• No previous colonoscopy attempted

For a small proportion of patients a complete colonoscopy is unsuccessful due to technical and physical reasons. This will be the study population which will be invited to participate in this study.