Rectal Spacer
What is a Rectal Spacer?
A rectal spacer is a temporary, biodegradable hydrogel (a soft gel-like substance that breaks down naturally in the body) placed between the prostate and rectum before radiotherapy for prostate cancer. The gel creates a protective gap to help reduce radiation exposure to the rectum during treatment. This is a minimally invasive procedure, done with minimal incisions or tissue disruption.
When is a Rectal Spacer Recommended?
A rectal spacer may be recommended in the following situations:
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Planned external beam radiotherapy for prostate cancer
Patients scheduled to receive radiation treatment to the prostate can benefit from the protective spacing the gel provides between organs.
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Close proximity of rectum to prostate
When imaging shows the rectum sits particularly close to the prostate, increasing the risk of radiation affecting the rectum.
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Previous bowel conditions
Patients with a history of inflammatory bowel disease, previous rectal surgery, or heightened sensitivity to radiation .
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High-dose radiation therapy
When higher doses are used, the spacer helps maintain bowel function and comfort throughout treatment.
Benefits of Rectal Spacer Treatment
Placing a rectal spacer offers several advantages for patients undergoing prostate radiotherapy:
- Reduced radiation to the rectum: The gel creates approximately 1.3 cm of space between the prostate and rectum, helping to reduce the amount of radiation reaching healthy bowel tissue.
- Fewer bowel-related side effects: Patients typically report less rectal bleeding, urgency, and discomfort during and after radiotherapy.
- Temporary and biodegradable: The hydrogel naturally breaks down and is absorbed by the body over approximately six months, requiring no removal procedure.
- Optimal radiation delivery: With the rectum shielded, radiation can be delivered more accurately to the prostate.
Types of Rectal Spacers Available
Several types of rectal spacers may be used, all with similar protective purposes:
SpaceOAR Hydrogel: A gel made from polyethylene glycol (a medical-grade material used in various healthcare applications), injected as a liquid and quickly solidifies to form a stable barrier.
SpaceOAR Vue Hydrogel: Similar to the standard SpaceOAR but contains iodine, making it visible on CT scans throughout the radiotherapy planning and treatment process.
Preparing for Rectal Spacer Treatment
Preparation steps include:
Medical evaluation
Your urologist will review your medical history, current medications, and any allergies, particularly to contrast agents or local anaesthetics.
Bowel preparation
You may be asked to use an enema on the morning of the procedure to clear the rectum, allowing better visualisation during placement.
Day of procedure
Arrive with an empty bladder, wear comfortable clothing, and arrange for someone to drive you home if sedation is planned. Light meals are usually permitted, though specific instructions will be provided based on your anaesthesia plan.
What Happens During Rectal Spacer Treatment
The procedure involves several key steps:
- Pain relief: Local anaesthetic will be applied around the injection site to ensure comfort.
- Ultrasound guidance: A transrectal ultrasound probe (an imaging device inserted into the rectum to guide placement) is used to visualise the prostate and rectum.
- Hydrogel injection: A thin needle is guided by ultrasound to inject the hydrogel into the small natural space between the prostate and rectum.
- Gel solidification: The hydrogel transforms from liquid to soft solid within 10 seconds, creating the protective barrier.
- Completion: The probe and needle are removed. You’ll be monitored briefly and usually discharged within 30 minutes.
Recovery and Aftercare
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Immediate aftercare
Rest at home for the first 24 hours and avoid strenuous activities, though normal walking and light tasks are encouraged. Mild pelvic pressure or urgency to urinate is normal and typically resolves within a day or two.
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Recovery timeline
Most patients return to normal activities within 1-2 days. Your radiation treatment typically begins 1-2 weeks after spacer placement, allowing any swelling to subside. The spacer remains stable throughout your radiotherapy course.
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Follow-up care
No specific follow-up is needed for the spacer itself, as it naturally absorbs over approximately six months. Continue with your scheduled radiotherapy as planned.
Get an Accurate Diagnosis & Proper Treatment
for Your Urological Conditions
Potential Risks and Complications
Rectal spacer placement is generally a well-tolerated and low-risk procedure. Occasionally, mild effects such as temporary injection site discomfort, brief rectal spotting, or short-term changes in bowel or urinary habits may occur and usually resolve on their own. Having the procedure performed by a qualified urologist in Singapore ensures that you receive expert care, personalised risk assessment, and appropriate follow-up to support a safe and effective outcome.
Dr Lee Fang Jann 
Dr Lee is a urologist and kidney transplant surgeon with a broad-based expertise of all urological disorders
He has subspecialty focus on men’s health and male infertility, and special interest in minimally invasive prostate enlargement therapy and kidney stone treatment. Dr Lee has received numerous awards for service excellence such as the Service With A Heart Award (2006-2008, 2011) and the Singapore Health Quality Service Award (2016).
- Bachelor of Medicine and Bachelor of Surgery (Singapore)
- Membership of The Royal College of Surgeons (Edin)
- Master of Medicine (Surgery) (Singapore)
- Fellowship of the Academy of Medicine (Urology)
- Clinical fellowship at Oxford Transplant Centre in the UK
Prior to entering private practice, Dr Lee served in the public sector for 16 years at SGH, where he initiated dedicated clinics evaluating and treating patients with complex men’s health and fertility issues. He also led the Renal Transplant Program and laparoscopic donor nephrectomy service as Surgical Director.
Apart from clinical work, Dr Lee is active in academia and believes in the importance of grooming the next generation of doctor. He was Senior Clinical Lecturer at NUS’ Yong Loo Lin School of Medicine and currently, Adjunct Assistant Professor at the Duke-NUS Medical School. Dr Lee is also regularly invited to share his experiences locally and regionally through lectures, workshops and surgical demonstrations.
Our Clinic Locations
Farrer Park Medical Centre, #08-05
1 Farrer Park Station Rd, Singapore 217562
Mon – Fri: 8:30am to 5:30pm
Sat: 8:30am to 12:30pm
3 Mount Elizabeth, #11-16 Medical Centre, Singapore 228510
Mon – Fri: 8:30am to 5:30pm
Sat: 8:30am to 12:30pm
Frequently Asked Questions
Will I feel the spacer inside me?
Most patients cannot feel the spacer once the initial placement discomfort subsides, usually within 24-48 hours. The gel is soft and flexible, moving naturally with your body.
Can I have an MRI scan with the spacer in place?
Yes, the hydrogel spacer is MRI-compatible and won’t interfere with any imaging you may need during or after your treatment.
What happens if my radiotherapy is delayed?
The spacer remains stable for many months, so moderate delays in starting radiotherapy don’t affect its protective function.
Will the spacer affect my bowel movements permanently?
The spacer shouldn’t cause any permanent changes to bowel function. As it gradually absorbs over six months, your anatomy returns to its normal state.
How soon can I return to work after the procedure?
Most patients can return to desk work the next day and more physical work within 2-3 days, depending on comfort levels.