Sacralization is a common irregularity of the spine, where the fifth vertebra is fused to the sacrum bone at the bottom of the spine. The fifth lumbar vertebra, known as L5, may fuse fully or partially on either side of the sacrum, or on both sides. Sacralization is a congenital anomaly that occurs in the embryo.
Sacralization often has no symptoms. It’s sometimes is associated with lower back pain or problems with posture and movement. It's also called lumbosacral transitional vertebrae or LSTV.
The extent and type of sacralization varies widely from individual to individual. Some people with sacralization have lower back pain. It’s not clear whether sacralization causes the back pain. Study results have been mixed.
The association between sacralization and lower back pain was
A 2013 review of medical studies of lower back pain found that the number of people with lower back pain who also had sacralization ranged from 6 to 37 percent. A
Other symptoms associated with sacralization may include:
- arthritis at the fusion site
- disc degeneration
- biomechanical difficulties in movement
- limits to range of motion
- posture control problems
- leg pain, buttock pain
Sacralization has several forms, classified according to whether the fusion seen on an X-ray is partial or total, and whether the fusion is on only one side (unilateral) or both (bilateral). The commonly used Castellvi classification is:
- Type 1: a fusion at least 19 mm in width on one (1a) or both sides (1b)
- Type 2: incomplete fusion with a pseudo joint created on one side (2a) or both sides (2b)
- Type 3: complete fusion of the L5 to the sacrum on one side (3a) or the other (3b)
- Type 4: combination of Type 2 and Type 3
The cause of sacralization isn’t yet known. It occurs during embryonic development, when the vertebrae begin to ossify, in about the eighth week.
There may be a genetic predisposition involved.
Among people under 30,
To diagnose this condition, your doctor will first examine you and ask about your medical history and any pain you may have.
A sacralization diagnosis also requires X-rays of the lumbar spine. You may have flexion-extension X-rays, so that the doctor can view the lumbar region in different positions.
Your doctor may also order MRI imaging. To confirm a diagnosis, your doctor may use diagnostic injections of anesthetics or steroids in the area.
Treatment depends on the type and degree of sacralization and what your symptoms are. Each individual is different, and there’s no set treatment. The conservative treatment given for pain associated with sacralization is the same as for other lower back pain.
This may include the standard treatments for lower back pain:
- anti-inflammatory drugs
- muscle relaxants
- steroid injections
If you don't get relief from steroid injections, this
Physical therapy can help to strengthen and stabilize the muscles involved and improve movement.
Chiropractic techniques are also
There are a few studies of other promising treatments.
A local anesthetic combined with radiofrequency strips in the pain area is
Surgery may be recommended to correct specific disc or other abnormalities that result from the sacralization. For example, sacralization may cause strain on the disc between the fourth and fifth vertebrae, leading to disc slippage or degeneration. It can also cause compression of the spinal nerve and pain in your spine or legs, scoliosis, or sciatica.
Sacralization is a common congenital abnormality that often has no symptoms. Whether or not it causes back pain has been a subject of debate since sacralization was first described. If you have pain symptoms, conservative and surgical treatments are available.