What are the indications for a hydrogel spacer & fiducials?
A spacer and fiducials may be recommended when you have chosen radiotherapy to treat prostate cancer. Although they are often inserted at the same time, they perform slightly different roles:
- Hydrogel Spacers
Create space between the prostate and rectum, reducing radiation exposure to the bowel and lowering the risk of treatment-related side effects. - Fiducial Markers
Provide a precise 3D target within the prostate, allowing the radiotherapy team to line-up the prostate more accurately, improving effective radiation dose and reducing bladder and bowel side-effects.
What are the alternatives?
- Radiotherapy without a spacer or fiducials — Treatment performed without a spacer or fiducial markers, with a slightly higher dose reaching the bladder and bowel.
- Radiotherapy with hydrogel only — Some radiotherapy machines are equipped with advanced CT scanning software to eliminate the need for fiducial markers.
- Other cancer treatments — Such as surgery or active surveillance, depending on your diagnosis.
What happens before surgery?
You will be asked to attend for a pre-operative assessment approximately 2-3 weeks before surgery, where blood tests and an ECG are typically performed to ensure the procedure takes place with minimal risk. Most patients should continue regular medication, although certain medications should be stopped prior to surgery. Please tell the team if you take blood thinners or have any implants, a pacemaker or a history of MRSA.
On the day of surgery you should avoid eating for six hours before, and drink only clear fluids within 2 hours of the procedure. You will be given a gown and compression stockings to wear, your consent will be confirmed, and an anaesthetist will discuss your anaesthetic and pain relief.
What does the procedure involve?
The spacer and markers are placed through the perineum — the skin between the scrotum and rectum — using ultrasound guidance.
- Usually carried out under general anaesthetic as a day case.
- Tiny gold fiducial markers are placed into the prostate to act as a 3D target.
- A soft hydrogel (such as SpaceOAR® or Barrigel®) is placed between the prostate and the rectum.
- The gel acts as a cushion, holding the bowel away from the treatment area, and is naturally absorbed by your body over a few months.
What are the side-effects?
Inserting a perirectal spacer is considered very safe, and complications are uncommon. Side-effects include:
- Mild perineal discomfort or bruising for a few days (almost all patients).
- A sensation of rectal fullness, irritation or constipation (30-50%).
- Gel placed in an unintended position, or a reaction to it (very rare).
- Non-uniform (asymmetric) gel placement, dependent on anatomy.
What happens after surgery?
Most men go home the same day and return to normal activities quickly. Any perineal soreness settles within a few days and is eased by simple painkillers.
Once the procedure is complete, your radiotherapy team will be informed directly, allowing your planning scan and radiotherapy treatment to proceed without delay.