- Minimally Invasive Access: The transanal approach accesses the surgical site through natural openings, preserving the external anal sphincter muscles and surrounding structures, and reducing trauma to nearby tissues.
- No Visible Scarring: Operating through the anal canal eliminates external incisions, preventing visible scars and minimising wound-related complications.
- Preservation of Bowel Function: By maintaining the integrity of sphincter muscles and surrounding structures, the procedure helps support normal continence and bowel control.
- Option for Local Anaesthesia: Some transanal procedures can be performed under local anaesthesia with sedation, reducing the risks and recovery associated with general anaesthesia.
- Faster Recovery: Patients typically experience shorter hospital stays and quicker resumption of daily activities compared to traditional surgical approaches.
Transanal Surgery

Dr Chong Choon Seng
MBBS | MRCS | Masters in Medicine (Surgery) | FRCS (Edinburgh)
Transanal surgery refers to minimally invasive procedures that are performed through the anal canal to treat conditions of the lower rectum and anal canal. Using specialised instruments inserted through the anus, this approach allows surgeons to remove tissue or repair defects while avoiding external incisions. It reduces recovery time, minimises tissue disruption, and preserves normal bowel function, providing effective treatment with fewer complications for various rectal conditions.




Indications for Transanal Surgery
Transanal surgery is typically performed to manage specific conditions affecting the rectum and anal region. The primary indications are:
- Early-Stage Rectal Tumours and Polyps: Benign tumours, early-stage cancers, and large or sessile rectal polyps unsuitable for removal during routine colonoscopy can be excised using transanal techniques to prevent progression and preserve healthy tissue.
- Anal Fistulas: Abnormal connections between the anal canal and surrounding tissues can be treated through transanal approaches, focusing on repairing the fistula’s internal opening.
- Haemorrhoids: Advanced internal haemorrhoids that do not respond to conservative treatments may require surgical removal via transanal methods.
- Rectal Prolapse and Strictures: Partial or complete rectal prolapse and rectal strictures (narrowing due to scar tissue) can be managed with transanal techniques to restore normal anatomy and function.
- Anorectal Abscesses: Deep or complex abscesses in the anorectal region can be effectively drained using transanal surgical approaches.
Benefits of Transanal Surgery
Transanal surgery offers several advantages over traditional surgical methods. The key benefits include:
Surgical Techniques
Transanal Endoscopic Microsurgery (TEM)
TEM uses a rigid scope and specialised tools to remove tumours, polyps, or other growths located deeper in the rectum. The magnified view helps the surgeon work precisely in hard-to-reach areas. This method is often used for larger or more complex cases.
Transanal Minimally Invasive Surgery (TAMIS)
TAMIS involves using laparoscopic tools through a specialised port placed in the anal canal. This technique provides more flexibility and precision than standard methods and is less invasive than TEM, making it suitable for a wider range of patients.
Traditional Transanal Excision
This method uses standard surgical tools inserted directly through the anal canal to remove growths in the lower rectum. It is best for smaller, well-defined lesions located close to the anus.
Preparing for Surgery
Medical Evaluation
A comprehensive medical evaluation, including a physical examination, medical history review, and diagnostic tests such as blood tests and imaging studies, is necessary to determine the procedure’s suitability. Additional tools, such as colonoscopy, endorectal ultrasound, or MRI, may be used to assess the condition’s extent and precise location.
Medication Adjustments
Certain medications, such as blood thinners or anti-inflammatory drugs, may need to be stopped temporarily before surgery. The surgeon will provide clear instructions to adjust medications safely while balancing the risk of complications.
Bowel Preparation
Patients need to cleanse their bowel 24-48 hours before surgery. This involves following a clear liquid diet and using prescribed laxatives or enemas. Proper bowel preparation ensures optimal visibility during the procedure and helps reduce the risk of infection.
Fasting Guidelines
Patients must avoid solid food for at least 8 hours before surgery. Clear liquids may be allowed up to 2 hours before the procedure. The surgeon will provide specific fasting instructions based on the timing of the surgery.
Step-by-Step Procedure
Anaesthesia Administration
The procedure begins with general or regional anaesthesia to ensure the patient remains comfortable and pain-free. The type of anaesthesia is chosen based on the procedure’s complexity and the patient’s medical needs.
Insertion of Surgical Instruments
A rectoscope or similar device is gently inserted into the rectum to access the area being treated. Specialised surgical tools are used to minimise trauma to nearby tissues.
Removal of Abnormalities
The surgeon removes polyps, tumours, and other growths while preserving the surrounding healthy tissue. The goal is to remove the abnormal tissue completely while causing as little disruption as possible.
Inspection and Closure
Once the abnormal tissue is removed, the surgeon carefully inspects the surgical site to ensure no issues remain. If necessary, the area is closed with absorbable sutures or left to heal naturally, depending on the size and location.
Completion and Dressing
After the surgery, the instruments are removed, and the area is cleaned. A dressing may be applied if needed. The patient is then moved to a recovery area for monitoring and post-surgical care.
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Post-Surgical Care and Recovery
Immediate Care
Patients are observed in a recovery area for several hours to monitor for bleeding, pain, or other complications. Pain management and hydration are provided as needed. Mild to moderate discomfort in the anal region is common and addressed with medication.
Recovery Process
Most patients can return home within 24 hours. During the first 24-48 hours, a clear liquid diet is followed, transitioning to regular foods as bowel function normalises. Gentle walking is encouraged to prevent blood clots and promote healing.
Stool softeners may be recommended to ease bowel movements, and regular sitz baths can help keep the surgical area clean and reduce discomfort. Strenuous activities, including heavy lifting, should be avoided for 2-4 weeks.
Follow-Up
The first follow-up appointment typically occurs 1-2 weeks after surgery to assess healing. Additional visits may be scheduled to monitor recovery progress and address any concerns. Long-term follow-up may include periodic examinations or imaging, depending on the initial condition treated.
Potential Risks and Complications
While transanal surgery is generally safe, potential risks include bleeding, infection (indicated by pain, fever, or unusual discharge), and temporary changes in bowel habits or gas control. Rare complications may involve scarring, narrowing of the surgical site, or altered sphincter function during healing. In cases of tumour removal, there is a small risk of incomplete excision or recurrence.
Frequently Asked Questions
How long does the procedure take?
The duration of transanal surgery depends on the specific condition being treated, but most procedures typically last 1 to 2 hours. Your surgeon will provide details based on your individual case.
Can transanal surgery treat all rectal conditions?
Transanal surgery is effective for many rectal conditions but may not be suitable for advanced or complex cases. In such situations, alternative treatments, such as endoscopic procedures or more extensive surgeries, may be recommended.
What dietary changes should I make after surgery?
After surgery, patients are usually advised to follow a soft or liquid diet for a few days to avoid straining during bowel movements. Your surgeon will provide specific dietary guidelines tailored to your recovery needs.
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Dr Chong Choon Seng
MBBS (NUS)
MRCS (Edinburgh)
Masters in Medicine (Surgery)(NUS)
FRCS (Edinburgh)
Dr Chong is the former Program Director of General Surgery Residency at NUHS, and has more than 10 years of experience as a colorectal and general surgeon.
As an esteemed professional in minimally invasive surgery, Dr. Chong remains committed to achieving optimal outcomes for all surgical conditions, from piles to cancer treatment.
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Ark Surgical Practice – Mouth Elizabeth Medical Centre
3 Mount Elizabeth, #17-01
Singapore 228510
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Ark Surgical Practice – Mount Elizabeth Novena Hospital
38 Irrawaddy Road, #09-34
Singapore 329563
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Saturday: 9am – 12:30pm
Sunday & Public Holidays: Closed