Low incidence of nerve injury found in patients with sacral fractures

Surgeons should analyze CT scans closely to identify spinopelvic dissociation.

Issue: December 2016

NATIONAL HARBOR, Md. — Researchers discovered nerve injury is rare in patients with sacral fractures, according to a presentation at the Orthopaedic Trauma Association Annual Meeting.

“Nerve injury with sacral fractures is rarer than we thought,” Anna N. Miller, MD, FACS, associate professor of the Department of Orthopedic Surgery at Washington University, told Orthopedics Today. “If you do find a patient who has a nerve injury, their fracture is probably more severe than you think and you need to take a close look to make sure you are not missing anything.”

Denis classification

Using the Denis classification, Miller and her colleagues analyzed fine-cut CT scans of 683 patients with sacral fractures in a series of 1,507 patients with pelvic fractures. Researchers compared the percentage of neurologic injuries associated with sacral fractures in this cohort of patients with the percentage found in an original paper published by Francis Denis, MD.

“Our results showed that overall nerve injury rates were lower than the original study — from 21.6% as Denis reported to 3.5% in our study. Nerve injury did correlate with having a more displaced comminuted fracture, as well as having a zone 2 or 3 sacral fracture,” Miller said in her presentation.

Researchers found 66% of patients had zone 1 sacral fractures, 25% had zone 2 fractures and 9% had zone 3 fractures, with nerve injuries associated with 1.9% of zone 1 fractures, 5.8% associated with zone 2 fractures and 8.6% associated with zone 3 fractures.

“The Denis classification correlated with having slightly more nerve injuries with the higher zone injury, but it was still less than the original paper,” Miller said in her presentation.

Results showed a significant correlation between patients with nerve injury and spinopelvic dissociation and comminuted fracture patterns compared with patients without nerve injury. In addition, patients with nerve injury frequently had zone 3 injuries and more often underwent surgical intervention.

Spinopelvic dissociation

According to Miller, patients with a nerve injury may have spinopelvic dissociation, which is easy to miss and important for surgeons to identify.

“Spinopelvic dissociation is easy to miss because it is hard to see on regular X-rays and some views on the CT scan,” Miller said. “It is important for [surgeons] to analyze the CT scan closely, and if the patient does not have a CT scan, we recommend they get one with thin cuts.”

She stated future research should evaluate if a certain subset of patients with spinopelvic dissociations have a higher rate of nerve recovery compared with other patients.

“I would like to look more into the spinopelvic dissociation itself [to see whether] those patients get any nerve recovery, if there are certain types of patients who get better nerve recovery than others and if earlier intervention can help them,” Miller said. – by Casey Tingle

Reference:
Khan J, et al. Paper #51. Presented at: Orthopaedic Trauma Association Annual Meeting; Oct. 5-8, 2016; National Harbor, Md.

For more information:
Anna N. Miller, MD, FACS, can be reached at Washington University and Barnes-Jewish Orthopedic Center in Chesterfield, 14532 S. Outer Forty Dr., Chesterfield, MO 63017; email: milleran@wudosis.wustl.edu.

Disclosure: Miller reports no relevant financial disclosures.