Sacral Fractures

sacrum fracture
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The sacrum is the bone in the back of the pelvis, at the bottom of the spine.  The sacrum is a heart shaped bone and on each side is attached to the iliac bones, above to the lumbar spine, and below to the coccyx (tailbone).  The joints that connect the sacrum to the iliac bones of the pelvis are called the sacroiliac joints, or SI joints.

Injuries to the sacrum are uncommon, and often overlooked.  Especially in the setting of severe traumatic injuries, sacral injuries often occur in conjunction with other more severe injures to the pelvis and/or abdomen.

 

Traumatic Sacral Fractures

Traumatic fractures of the sacrum can occur in conjunction with other types of pelvic and spinal fractures. These injuries commonly occur as a result of serious high-energy injuries including motor vehicle collisions and severe falls.  About half of traumatic sacral fractures are associated with injuries to the nerves that exit the lowest segments of the spinal cord.

Sacral Stress Fractures

A sacral stress fracture occurs in young, active patients, commonly seen in female long-distance runners. These injuries are closely related to sacral insufficiency fractures, but the bone is usually not osteoporotic. Rather than the bone not being healthy enough, the activities simply are too much for the sacrum to withstand, and a stress fracture results.

Symptoms of a sacral stress fracture most commonly include back and buttock pain, and pain with activities such as running.

Treatment must include resting from activities that cause pain. Usually with a period of rest, the symptoms will resolve. Gradual resumption of activities is important to prevent a recurrence.

Sacral Insufficiency Fractures

Sacral insufficiency fractures occur in elderly patients with osteoporosis. These injuries may be the result of a fall or may be the result of no particular injury.

Patients commonly complain of symptoms of low back and buttock pain.

Sacral insufficiency fractures may not be seen on regular x-rays, but usually show up on MRI or CT scans of the pelvis. The treatment of a sacral insufficiency fracture is usually symptomatic relief with rest and ambulatory devices such as a walker or cane.

Sources:

Mehta S, Auerbach JD, Born CT, Chin KR. "Sacral fractures" J Am Acad Orthop Surg. 2006 Nov;14(12):656-65.

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