Sacroplasty

The sacrum is the large, shield-shaped bone at the bottom of the spine, between the two hip bones. It carries the weight of the upper body into the pelvis and legs. When the bone is weak, everyday stress such as walking or stepping off a curb can crack it. This is called a sacral insufficiency fracture.

The fracture causes deep pain in the low back, buttocks, hips or groin, worse when standing or walking and better lying down. Because the pain is vague, it is often mistaken for arthritis, a slipped disc or a hip problem. Regular X-rays miss most of these fractures.

On MRI, the fracture shows as bright swelling along one or both sides of the sacrum. On a bone scan, fractures on both sides with a bar across the middle can form an H shape, a classic sign. CT shows the thin fracture lines and helps plan the needle path.

Sacroplasty is similar to kyphoplasty for spine fractures. Using CT or live X-ray, the doctor guides one or more needles into the cracked areas of the sacrum and slowly injects medical-grade bone cement (PMMA). The cement hardens within minutes and supports the bone from inside, so the broken edges stop moving. That movement is what causes most of the pain.

Sacroplasty has been studied more than ramiplasty but less than kyphoplasty. Large observational studies show fast and lasting pain relief, but there are no large randomized trials comparing it with a sham procedure yet.

Many sacral fractures heal with rest, pain medicine, physical therapy and a walker, but healing can take 3 to 6 months or longer. During that time, older adults can lose strength, fall, develop blood clots or pneumonia, and lose independence. Sacroplasty aims to shorten that painful period.

A newer surgical option places screws across the sacrum through small incisions, sometimes combined with cement. It is generally used for less stable fractures. For cancer, radiation therapy is often part of the plan. Standard care also always includes treating osteoporosis.

More general advice is on before your procedure and sedation.

1. 1
   Preparing

   You lie on your stomach on the CT or X-ray table. You receive sedation or general anesthesia and antibiotics through your IV. The skin over the lower back and buttocks is cleaned and numbed.

2. 2
   Placing the needles

   Using CT or live X-ray, the doctor guides one or two needles into each fractured side of the sacrum, carefully avoiding the openings where the nerves to the legs pass through.

3. 3
   Injecting the cement

   Bone cement is injected slowly while images check that it fills the fracture and stays inside the bone.

4. 4
   Finishing

   The needles are removed and the punctures are sealed with skin glue. The procedure usually takes about 1 hour.

You lie on your back for about 1 to 2 hours while the cement fully hardens. Nurses check your leg strength and feeling. Most people go home the same day, and those who were already in the hospital may stay longer.

1. First day
   Rest. Soreness at the needle sites is normal. Walk with help when you feel ready. No driving after sedation.
2. First week
   Walk several times a day with your walker or cane. Many people notice easier walking within a few days. Shower after 24 hours, but no baths or pools for 1 week.
3. Weeks 2 to 6
   Continue physical therapy and slowly return to your normal routine. Your doctor may lower your pain medicines.
4. Longer term
   Make a plan with your primary care doctor or endocrinologist to treat osteoporosis and prevent future fractures.

In published studies, including a large study that followed patients for 10 years, most people had a large drop in pain within the first days to weeks, and the relief lasted. Many were able to walk more and take fewer pain medicines. Results vary, and some people improve less.

Sacral fractures are one of the most missed causes of low back and buttock pain in older adults, especially after pelvic radiation. When I see a patient with this kind of pain, I look for the fracture lines on MRI or CT and make sure they match where it hurts. For someone who has gone from walking independently to barely getting to the bathroom, getting them moving again quickly can make a real difference.

Fabio Komlos, MD, interventional radiologist · About Dr. Fabio Komlos