Orthopedic study notes importance of radiographic evaluation of sacral kyphosis

DENVER — Although lumbosacral dissociation is uncommon, new research indicates a high rate of sacral kyphosis in these cases and highlights the importance of evaluation for this deformity.

“High energy lumbopelvic dissociations must be evaluated for sacral kyphosis when choosing your operative fixation,” H. Michael Frisch, MD, said during his presentation at the 24th Annual Meeting of the Orthopaedic Trauma Association. “A few of our patients treated nonoperatively with greater than 20° of kyphosis progressed, while none of the patients treated with sacroiliac screw fixation or posterior instrumentation did. Sacral kyphosis must be considered when developing your treatment plan for these injuries.”

Combat-related injuries

In a retrospective review, Frisch and his colleagues studied 15 patients who were treated at Walter Reed Army Medical Center for combat-related lumbosacral dissociation and had a minimum 1 year follow-up. The patients had radiographic evidence of an H-or U-type zone III sacral fracture and associated lumbar fractures with a loss of iliolumbar ligamentous complex integrity. “The most common mechanism of injury was an improvised explosive device (IED) blast under a vehicle,” Frisch said.

Using sagittal reconstructions of CT scans, the investigators discovered that 11 patients had evidence of sacral kyphosis at the time of presentation. These patients had a mean kyphosis of 12°. Of the 15 patients in the study group, seven patients underwent sacral iliac screw fixation, four had posterior spinal fusion and four received nonoperative care as their initial treatment. The patients had an average follow-up of 1.7 years.

VAS pain scores

“At most recent follow-up two patients, both with greater than 20° of kyphosis [who were] initially treated nonoperatively, had progression of their sacral kyphosis,” Frisch said during his presentation. “One patient required sacral decompression for associated nerve root impingement, while the other had pain but no signs of impingement.”

At greater than 1-year follow-up, six patients reported pain with a mean visual analog scale (VAS) pain score of 4. However, the overall study group had a mean (VAS) pain score of 1.6.

“Twelve patients had no evidence of sacral nerve root symptoms, while three had persistent bowel or bladder dysfunction,” Frisch said. “One was treated subsequently with sacral decompression, and two did not have any evidence on imaging of compression.”

For more information:
H. Michael Frisch, MD, can be reached at Mission Hospital, 509 Biltmore Ave., Asheville, NC 28801; 828-213-1994. He has no direct financial relationship with any product or company mentioned in this article.

Reference:
Lehman RA, Moore MF, Andersen RC, et al. Sacral kyphosis as a cause of sacral nerve impingement in lumbosacral dissociations. Paper #5. Presented at the 24th Annual Meeting of the Orthopaedic Trauma Association. Oct. 16-18, 2008. Denver.