The purpose of this clinical investigation is to evaluate the safety of the ColoSeal ICD System by evaluating its effectiveness in reducing the stoma creation rate and by comparing the rate of major complications to current standard of care for rectal cancer surgery with a diverting ostomy.

The ColoSeal Intraluminal Colonic Diversion (ICD) System, comprised of the ICD Device and the ICD Device Delivery System, is a minimally invasive medical device designed to temporarily protect a colonic anastomosis from fecal flow. It is initially intended as a less invasive alternative to temporary protective (diverting) ostomy surgery for patients with rectal colon cancer who are undergoing colon resection with reconstruction with an anastomosis.

Inclusion Criteria:

1. Subject is 22-75 years of age at screening and is diagnosed with rectal cancer.
2. Subject is determined to be 'robust' as assessed via the Clinical Frailty Scale (CFS; score 1-3), the Mini-Cog (score ≥3) and either the Short Physical Performance Battery (SPPB; score ≥10) or Timed Up and Go (TUG; score <12 seconds). This inclusion applies to subjects aged 71-75 only.
3. Subject is scheduled for elective sphincter sparing resection, either open, laparoscopic or robotic with mesorectal excision (either abdominal or transanal approach).
4. Subject requires the creation of a stapled anastomosis maximally 10 cm from the anal verge, and minimally with sufficient distance from the anal verge to accommodate use of an anastomotic stapler.
5. Subject has been informed of the study's nature, agrees to its provisions, and has provided written informed consent, which has been approved by the appropriate Ethics Committee (EC) or Institutional Review Board (IRB).
6. Subject must have a designated (lay or professional) caregiver available in the in-home setting while the ICD System is in use.
7. Subject should live within ≤ 75 miles (120 km) of their study investigator's facility. If outside of this range, subjects must be willing to stay in accommodations ≤ 75 miles (120 km) of the investigator's facility for 1-day post-study device removal.
8. Subject must be willing and able to comply with protocol requirements, including study follow-up visits.

Exclusion Criteria:

Preoperative:

1. Subject at the time of baseline screening is not planned to have ostomy reversal prior to 6 months post-index procedure.

2. Subject with a life expectancy < 1 year due to condition other than rectal cancer.

3. Subject with American Society of Anesthesiologists (ASA) classification > 3.

4. Subject has a systemic infection at the time of surgery or requiring systemic antimicrobial therapy up to 1 week before surgery.

5. Subject had major surgical or interventional procedure within 30 days before the index procedure or planned major surgical or interventional procedure within 30 days after the index procedure.

6. Subject has received systemic chemotherapy or radiation to the pelvis within 30 days before the planned procedure.

7. Subject has a diagnosis of bowel obstruction, bowel strangulation, peritonitis, bowel perforation, ischemic bowel, carcinomatosis, diffuse descending colon diverticulosis (i.e., diverticula at potential planned fixation site), diverticulitis, or inflammatory bowel disease in the descending colon.

8. Subject has an anatomic abnormality (e.g., polyp, diverticula, vascular malformation) or bowel damage at or within 5 cm of the target device anchor site that could interfere with safe device function.

9. Subject has a diagnosis of coagulopathy (INR≥1.5), thrombocytopenia (platelet count <150,000/μL), or immune suppression (CD4+ T-cell count <500 cells/mm³).

10. Subject has a condition resulting in significant cognitive impairment and/or functional decline, such as dementia or advanced Parkinsons disease.

11. Subject has a BMI ≥ 40.

12. Subject is scheduled for a concurrent major surgical procedure during the index procedure (e.g., liver resection).

13. Subject has been taking regular systemic steroid medication in the last 6 months prior to the index procedure.

14. Subject is taking anticoagulants, antimetabolites or antiplatelet agents (Note: low-dose aspirin therapy is permitted) within 7 days of the index procedure.

15. Subject has undergone a prior pelvic anastomosis.

16. Subject has fecal incontinence, involvement of the sphincter by neoplastic disease, or evidence of extensive local disease in the pelvis seen on pre-operative imaging.

17. Subject is diabetic with hemoglobin A1c > 8.0% (64 mmol/mol).

18. Serum albumin of < 3.0 g/dL.

19. Serum prealbumin of <15mg/dL.

20. Subject has a known allergy to any component of the device.

21. Subject has a known allergy to iodine or iodine-based contrast unless the subject can be adequately premedicated before the leak test.

22. Subject has unresolved alcohol or drug abuse, in the investigator's opinion.

23. Subject is pregnant or planning to become pregnant (female subjects of childbearing potential must have a negative urinary pregnancy test ≤ 7 days before the surgical procedure).

24. Subject is unable or unwilling to provide informed consent.

25. Subject is currently participating in an investigational drug or another device study that clinically interferes with the current study endpoints.

    Intraoperative:

26. Subject is not planned to receive an ostomy placement at the time of the index procedure.

27. Subject's left colon (bowel) preparation on the day of surgery is deemed inadequate for ICD Device placement, as determined by the investigator.

28. Subject requires an end-to-end or side-to-end anastomosis smaller than 31 mm in diameter or greater than 10cm from the anal verge.

29. Subject failed intraoperative leak test.

30. Subject has any condition or abnormality which, in the opinion of the investigator, may jeopardize subject safety or the quality of the study data.