Written and medically reviewed by: Assoc. Prof. Cengiz Dibekoğlu, MD, General SurgeryLast updated:
Ultra-Low Anterior / Intersphincteric Resection
Sphincter-preserving effort for very distal tumors — partial internal sphincter resection with coloanal anastomosis when external sphincter can still be saved oncologically.
Ultra-low anterior resection and intersphincteric resection (ISR) are used for selected very distal rectal tumors when classic LAR cannot take an adequate distal margin, yet the external sphincter can still be preserved oncologically. Part of the internal sphincter may be resected; the anastomosis is usually coloanal. The aim is organ preservation instead of Miles — functional outcomes are more delicate. Completing that lowest part from below is discussed as TaTME. If the sphincter is involved, TaTME does not replace Miles.
Educational schematic. Some structures may be simplified or emphasized for clarity; not an exact anatomical depiction.
© Cengiz Dibekoğlu — illustrative; not for unauthorized use
Figure summary
- This educational figure shows: Ultra-low / intersphincteric resection.
- Related figures on this page: TME plane.
Related educational figures
Tap a figure to enlarge.
TME plane Educational schematic. Some structures may be simplified or emphasized for clarity; not an exact anatomical depiction.
© Cengiz Dibekoğlu — illustrative; not for unauthorized use
Figure summary
TME plane
Who may be a candidate?
- Very distal (low) rectal tumors
- No external sphincter invasion; R0 appears achievable with ISR
- Patients downstaged after neoadjuvant / TNT toward sphincter preservation
- Informed patients accepting functional risk instead of permanent stoma
Possible advantages
- Potential organ and sphincter preservation instead of permanent colostomy
- Oncologic clearance still pursues intact TME plus adequate distal margin
- Neoadjuvant shrinkage can improve ISR candidacy in selected cases
- A protective ileostomy is often used to shelter the coloanal join
Limits & realistic expectations
- External sphincter or levator invasion generally needs Miles (APR)
- Poor baseline continence may worsen quality of life after ISR
- Difficulty adhering to follow-up and rehabilitation is a relative contraindication
- Organ preservation can bring urgency, frequency, and leakage trade-offs
Step-by-step overview
- 1
Abdominal TME phase
Standard TME mobilizes the mesorectum in the pelvis; vascular pedicle and nerve-sparing principles match LAR.
- 2
Perineal / intersphincteric phase
Via an anal approach the intersphincteric groove is identified. Internal sphincter is resected as needed; external sphincter is preserved.
- 3
Specimen integrity
Abdominal and perineal dissections meet; tumor, mesorectum, and distal margin come out as one specimen.
- 4
Coloanal anastomosis
Colon is brought to the anal canal and joined (hand-sewn or stapler-assisted). Perfusion and tension are critical; colonic J-pouch or coloplasty may be considered (center preference).
- 5
Protective ileostomy
A temporary ileostomy is often added when the team considers the anastomosis at higher leak risk. Closure is planned after anastomotic healing.
Key points
Intersphincteric plane
Dissection descends between internal and external sphincter so the tumor can be cleared while aiming to leave the external sphincter.
Coloanal anastomosis
Colon is joined at anal-canal level. A protective ileostomy is commonly recommended when the anastomosis sits very low.
- Key note inside
Function trade-off
Organ preservation may come with frequent stools, urgency, and leakage risk. Some patients accept that risk; others prefer Miles after shared decision-making.
Role of neoadjuvant therapy
Downsizing can improve ISR margins. Decision still rests on MRI, examination, and tumor board — not every distal tumor is an ISR.
After surgery
Intensive stoma teaching and early clinic adherence; pelvic-floor rehab and diet adjustment; close watch for leak or pelvic sepsis; long-term continence scoring; LARS management after stoma closure.
- Key note inside
Important
Educational information only — ultra-low / ISR candidacy is MRI- and examination-driven and must be individualized.
Frequently asked questions
Is this always better than Miles?
In well-selected oncologically suitable patients it offers organ preservation; function is not ‘better than Miles’ for everyone. The decision is personal after counseling.
Is there still a permanent stoma risk?
The goal is temporary diversion. Severe leak, poor function, or recurrence / salvage surgery can lead to a permanent stoma.
Does removing internal sphincter affect continence?
Yes. More internal sphincter resected can increase urgency, night soiling, and leakage. Baseline sphincter function is assessed carefully before surgery.
Is a protective ileostomy mandatory?
It is usually recommended for very low coloanal anastomoses. It does not abolish leak risk but can lessen clinical impact. Final choice follows anastomotic and patient risk.
When does rehabilitation start?
Pelvic-floor training and diet advice can begin before stoma closure; after continuity is restored, close follow-up and personalized exercises continue.
More chapters in this hub
Rectal vs Colon Cancer
Differences from colon — explained for shared decision-making
Total Neoadjuvant Therapy (TNT)
Total neoadjuvant therapy — sequencing chemotherapy and radiation before surgery
Watch-and-Wait for Rectal Cancer
Non-operative management after clinical complete response — with strict surveillance
Rectal Cancer Operations
Operations: what the procedure aims to do and who it fits
Liver Metastases (colorectal)
When rectal cancer involves the liver: sequencing and hybrid liver treatment
Low Anterior Resection (LAR)
Sphincter-preserving resection with TME when tumor height allows
Abdominoperineal Resection (Miles)
When a permanent colostomy is the oncologically safer option
LARS After Rectal Surgery
Frequency, urgency, and leakage — diet, medicines, and pelvic rehab
TAMIS Surgery
Natural-orifice transanal local excision — no abdominal incision; single-port robotic TAMIS is a selected setup
TaTME
Selected mid and low rectal cancers: the lowest part is done through the anus, and the surgeon also works through the abdomen — not TAMIS
Recurrent Pelvic Rectal Cancer
Restaging, salvage surgery, and realistic goals after recurrence
Anal Canal Cancer
Squamous anal cancer — distinct from rectal adenocarcinoma; chemoradiation first
Appointment / info
This page is for education. It is not medical advice and does not replace a visit with your physician.
Medical editor: Assoc. Prof. Cengiz Dibekoğlu, MD · Last medically reviewed: August 2026 · English patient-education chapter.