Overview
Definition:
Transanal stapled excision (TSE) is a minimally invasive surgical technique used to remove large rectal polyps through the anus using a circular stapling device
This approach avoids abdominal incisions and is particularly useful for polyps located in the mid to upper rectum, which may be challenging to resect transanally with traditional methods or endoscopic techniques
Giant rectal polyps are defined by their significant size, often exceeding 4-5 cm in diameter, posing a higher risk of malignancy or complete obstruction.
Epidemiology:
Rectal polyps are common, with incidence increasing with age
Giant rectal polyps are rare, representing a small fraction of all polyps
Their occurrence is not strongly associated with specific demographics, although they can be found in any age group
The risk of malignancy in giant rectal polyps is significantly higher than in smaller polyps, making timely and complete excision crucial.
Clinical Significance:
Giant rectal polyps can cause significant morbidity, including rectal bleeding, tenesmus, altered bowel habits, mucus discharge, and potentially partial or complete bowel obstruction
More importantly, they carry a substantial risk of harboring or developing colorectal cancer
Therefore, accurate diagnosis and complete, safe resection are paramount for both symptomatic relief and oncological control
TSE offers a less invasive alternative to traditional open surgery for these large lesions.
Clinical Presentation
Symptoms:
Intermittent rectal bleeding, often bright red
Change in bowel habits, such as increased frequency or constipation
Sensation of incomplete evacuation or rectal fullness
Passage of mucus or pus
Abdominal pain or cramping if obstruction is present
Rectal mass felt on digital rectal examination
May be asymptomatic and found incidentally.
Signs:
Digital rectal examination may reveal a palpable mass
Proctoscopy or sigmoidoscopy will visualize the polyp
Significant blood loss may lead to anemia
Vital signs may be normal unless there is acute obstruction or significant hemorrhage.
Diagnostic Criteria:
Diagnosis is typically made via colonoscopy or sigmoidoscopy with biopsy confirming the nature of the polyp (e.g., adenoma, serrated polyp, adenocarcinoma)
Size (>4-5 cm) is a key feature for classifying it as "giant"
Imaging such as MRI pelvis may be used to assess local invasion if malignancy is suspected.
Diagnostic Approach
History Taking:
Detailed history of rectal bleeding (frequency, volume, color)
Change in bowel habits (duration, nature)
Presence of tenesmus, pain, or discharge
Family history of colorectal polyps or cancer
Previous gastrointestinal surgeries or colonoscopies
Red flags: significant weight loss, persistent changes in bowel habits, iron deficiency anemia, family history of early-onset CRC.
Physical Examination:
General physical examination to assess for signs of anemia or systemic illness
Abdominal examination to rule out distension or masses
Digital rectal examination to assess the size, location, and mobility of the polyp if palpable
Proctoscopy or flexible sigmoidoscopy for direct visualization and biopsy.
Investigations:
Colonoscopy for full visualization of the colon and rectum, and biopsy of the polyp
Biopsy results are crucial to determine histology and grade of dysplasia or malignancy
Complete blood count (CBC) to assess for anemia
Stool occult blood test
For suspected malignancy or local invasion: CT scan abdomen/pelvis or MRI pelvis.
Differential Diagnosis:
Large inflammatory pseudopolyp
Rectal prolapse
Rectal cancer originating from the mucosa
Rectal leiomyoma or other mesenchymal tumors
Fecal impaction
Diverticular mass
Lymphoma of the rectum.
Management
Initial Management:
Depends on patient stability
If acute obstruction or severe bleeding, immediate resuscitation may be needed
For stable patients, diagnostic colonoscopy with biopsy is the first step
The goal is complete polyp removal.
Medical Management:
Primarily supportive
If anemic, iron supplementation and blood transfusions may be required
Antibiotics are not routinely indicated unless there is infection or peritonitis.
Surgical Management:
Transanal stapled excision (TSE) is indicated for large, sessile or pedunculated polyps in the mid to upper rectum (typically 6-18 cm from the anal verge) that are difficult or unsafe to remove endoscopically due to size, stalk, or risk of perforation
It involves inserting a circular stapling device through the anus to excise the polyp with a margin of normal tissue, simultaneously creating an anastomosis
Other options include transanal endoscopic microsurgery (TEMS) for lesions amenable to endoscopic dissection, or traditional open surgery (anterior resection) for very large or invasive lesions requiring wider margins or lymph node dissection
Conventional endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD) may be considered for smaller or selected larger lesions.
Surgical Steps Stapled Excision:
Patient positioning (lithotomy or prone)
Insertion of a rigid proctoscope or anoscope
Identification and mobilization of the polyp
Placement of purse-string sutures around the base of the polyp and normal rectal mucosa
Advancement of the circular stapler through the purse-string sutures
Firing the stapler to excise the polyp and seal the rectal wall defect
Removal of the stapler and excised specimen
Inspection of the staple line for hemostasis and integrity
Closure of the rectal defect is typically not required, allowing drainage.
Postoperative Care:
Pain management with analgesics
Intravenous fluids
Diet advancement as tolerated, usually starting with clear liquids
Monitoring for bleeding, fever, or signs of anastomotic leak
Antibiotics may be given prophylactically in some centers
Discharge typically occurs within 1-2 days if no complications
Follow-up colonoscopy is essential to ensure complete removal and monitor for recurrence or new polyp formation.
Complications
Early Complications:
Bleeding from the staple line (most common)
Rectal pain
Infection
Rectal perforation (rare with stapled techniques)
Urinary retention
Stenosis of the anal canal or rectum (rare)..
Late Complications:
Recurrence of polyp or adenoma at the excision site
Rectal stricture
Fecal incontinence (uncommon with TSE)..
Prevention Strategies:
Careful patient selection for TSE
Adequate exposure and visualization during surgery
Precise placement of purse-string sutures
Complete and secure stapler firing
Meticulous inspection of the staple line post-excision
Prompt recognition and management of bleeding
Adherence to postoperative bowel regimen and monitoring.
Prognosis
Factors Affecting Prognosis:
Histological grade of the polyp (dysplasia vs
adenocarcinoma)
Extent of invasion if malignant
Completeness of surgical resection
Presence of lymph node metastasis (if malignant)
Patient's overall health status
Recurrence rate is influenced by polyp size, morphology, and adherence to follow-up.
Outcomes:
For benign giant polyps, TSE offers excellent outcomes with high rates of complete removal and symptomatic relief
For early-stage rectal cancers within the polyp, TSE can be curative if margins are clear and no lymph nodes are involved
Recurrence rates are generally low with appropriate follow-up
Morbidity is significantly lower compared to open abdominal surgery.
Follow Up:
Regular surveillance colonoscopies are crucial
Typically, follow-up colonoscopy at 6 months to 1 year post-excision, then annually, and then every 3-5 years if no recurrence
This allows for early detection of any residual polyp, recurrence, or new polyp formation
Biopsy of any suspicious areas during surveillance is important.
Key Points
Exam Focus:
Indications for TSE in giant rectal polyps
Comparison of TSE with TEMS and open resection
Management of bleeding post-TSE
Understanding histological classifications of rectal polyps and their malignant potential
Differentiating benign from malignant giant polyps
Follow-up protocols for rectal polyps.
Clinical Pearls:
Giant polyps are not just big
they are often a red flag for malignancy, treat them with suspicion and a complete approach
Secure the polyp and a good margin of mucosa with the purse-string for optimal stapler function
Always confirm hemostasis of the staple line
Don't underestimate bleeding
prompt identification and intervention are key
A well-performed TSE spares patients significant morbidity.
Common Mistakes:
Attempting TSE for lesions too distal (below the dentate line) or too proximal requiring low anterior resection
Inadequate exposure or visualization leading to incomplete resection or injury
Not achieving adequate hemostasis on the staple line
Over-reliance on endoscopic techniques for polyps clearly exceeding their capabilities
Insufficient follow-up leading to missed recurrences.