What is SpaceOAR?

SpaceOAR is an absorbable hydrogel that temporarily creates space between the prostate and the rectum, thus protecting the rectum from radiation exposure during prostate radiation therapy. It is intended to temporarily position the anterior rectal wall away from the prostate to reduce the radiation dose delivered to the anterior rectum. The SpaceOAR hydrogel is composed of biodegradable material and maintains the space for the entire course of prostate radiotherapy treatment. It is then completely absorbed by the body over time.

Clinical data comparing patients with and without SpaceOAR hydrogel demonstrated the benefits of SpaceOAR hydrogel to include reduction of rectal toxicity resulting in less rectal bleeding, improved bowel function, improvements in urinary function, and a higher likelihood of maintaining sexual function.

How is it placed?

Either using local lidocaine anesthesia or under sedation, the SpaceOAR injection needle is guided through the perineum (the flat part of the bottom under the scrotum) into the correct position between the prostate and the rectal wall. Then 10 ml. of the liquid gel is injected into the identified space. The procedure takes about 10-15 minutes and patients may return home afterward.

Is it safe?

SpaceOAR is made of two liquids that when combined form a soft gel-like synthetic material that is mostly made of water. Because of its water content, it is called a hydrogel. The material that the SpaceOAR hydrogel is made from has been used in other implants such as surgical sealants used on the eye, brain, and spine. Studies have shown that the material is biocompatible and can be used safely in the body. SpaceOAR is naturally absorbed in about 6 months – well after completing the radiation treatments.

What are the risks?

When done correctly by a specialist who is trained in the technique, and does it often, the risks are very low. However potential complications associated with SpaceOAR hydrogel injection include, but are not limited to, pain or discomfort associated with SpaceOAR hydrogel, needle penetration of the bladder, prostate, rectal wall, rectum, or urethra; injection of SpaceOAR hydrogel into the bladder, prostate, rectal wall, rectum, or urethra; local inflammatory reactions; infection; injection of air, fluid or SpaceOAR hydrogel intravascularly; urinary retention; rectal mucosal damage, ulcers, necrosis; bleeding; constipation; and rectal urgency.

What can I expect after the procedure?

Most men have few or no symptoms after SpaceOAR placement. A small percentage will have mild perineal discomfort or spotting of blood from the injection sites. You may return to normal activity in 48 hours after the procedure but refrain from bicycle riding for one week.

This section was adapted from the spacOAR website, https://www.spaceoar.com.
  1. Hydrogel Spacer Prospective Multicenter Randomized Controlled Pivotal Trial: Dosimetric and Clinical Effects of Perirectal Spacer Application in Men Undergoing Prostate Image Guided Intensity Modulated Radiation Therapy. Mariados, Neil et al. International Journal of Radiation Oncology • Biology • Physics, Volume 92, Issue 5, 971 – 977
  2. Sexual quality of life following prostate intensity-modulated radiation therapy (IMRT) with a rectal/prostate spacer: Secondary analysis of a phase 3 trial. Hamstra, Daniel A. et al. Practical Radiation Oncology, Volume 8, Issue 1, e7 – e15
  3. Continued Benefit to Rectal Separation for Prostate Radiation Therapy: Final Results of a Phase III Trial. Hamstra, Daniel A. et al. International Journal of Radiation Oncology • Biology • Physics, Volume 97, Issue 5, 976 – 985

When should I call the doctor’s office after the procedure?

  • Temperature over 100.5 degrees Fahrenheit.
  • Bleeding in the urine or stool
  • Pain, more than a little discomfort for 2-3 days
  • Difficulty with urination or bowel movements.