To date, patients with Crohn's Disease (CD) and permanent ileostomies have been excluded from clinical trials for new treatments. To allow this patient population to be included in clinical trials, outcome and measurement tools are needed. This study aims to develop a Patient Reported Outcome (PRO) and Endoscopic Index (EI) for patients with Crohn's Disease (CD) and permanent ileostomy. The study will enroll about 50 participants and collect videos of endoscopies that are done as part of standard of care. The videos will be centrally read to identify features that represent a broad range of inflammation and will be used to develop the EI. Participants will also be asked to participate in interviews, to understand the symptoms and impacts that are most important to participants for the development of a PRO.

Inclusion Criteria:

1. Adults (age ≥ 18 years) with a diagnosis of CD treated surgically with subtotal colectomy/proctocolectomy end ileostomy at least 12 months prior to the scheduled endoscopy procedure.
2. Planning to have an ileoscopy procedure scheduled as part of routine medical care.
3. Be proficient in the English language (ie, ability to read, write, speak, and understand English well enough to take part in the interview process without the aid of an interpreter).
4. Able and willing to participate fully in all aspects of this study.
5. Written informed consent must be obtained and documented.

Exclusion Criteria:

1. End or loop colostomy, end ileostomy for UC, continent ileostomy, ileal pouch anal anastomosis, end ileostomy with mucous fistula, double barrel ileostomy, urostomy, loop ostomy, or any type of end ileostomy not considered permanent at the time of enrolment (with no intent to restore continuity).
2. Peristomal skin complications such as pyoderma gangrenosum, abscess, or any other severe peristomal skin inflammation.
3. Stomal stenosis obviating ileoscopy, known small bowel stricture, major stoma prolapse, symptomatic parastomal hernia, parastomal hernia with subcutaneous loops of small bowel within the hernia, stoma in a crease/poorly fitting applicable resulting in severe peristomal skin irritation, or retracted stoma that prevents endoscopic evaluation.
4. Any actively draining fistula (eg, peristomal or peri-anal).
5. Evidence of a known small bowel stricture on cross-sectional imaging or inability to pass an endoscope within the past 6 months.
6. Known active Clostridoides difficile or other enteric infection.
7. Short bowel syndrome.
8. Predominant symptom(s) arising from a retained rectal stump.
9. Serious underlying disease other than CD that in the opinion of the investigator may interfere with the participant's ability to participate fully in the study procedures or provide nonconfounded descriptions of their CD and ostomy symptom experiences during the interview.
10. Prior enrolment in the current study.

Approximately 50 participants who meet the inclusion and exclusion criteria will be enrolled in the study. The study population will ideally include approximately equal distributions of participants with disease activity categorized by a central reader as normal, mild, moderate, and severe, according to the VAS assessment. It is not possible to predetermine the number of participants with specific disease activity levels. The distribution of inflammatory disease activity across the study population will be monitored on an ongoing basis and recruitment strategies may be reviewed for opportunities to help maintain a balanced distribution. No more than 10 asymptomatic participants will be enrolled.