The pars interarticularis is a small part of the lamina that joins the facet joints in the back of the spine. Injury to the pars is a common cause of pediatric back pain. Pars fractures are particularly common in athletes such as football players or gymnasts who perform repetitive back extension.1 The incidence of spondylolysis in adolescent athletes has been reported to range from 47%2 to as high as 70% to 80%.3 Pars stress fractures and most nondisplaced pars fractures will usually present with normal radiographs. Standard anteroposterior and lateral radiographs are recommended for evaluation; oblique view radiographs do not offer any diagnostic benefit, despite their frequent use.

The advanced imaging study of choice to diagnose spondylolysis has been debated. Thin sliced MRI provides excellent diagnostic evaluation without radiation exposure. Bone scan is the most sensitive test but does require radiation exposure, although to a much smaller degree than computed tomographic imaging.

The prognosis with conservative treatment for spondylolysis is good, with healing rates >90%.4 Treatment involves rest, nonsteroidal anti-inflammatory drugs, physical therapy, and bracing. Active lumbar extension should be avoided as this increases shear forces across the back, as well as the risk of fracture displacement, instability, and spondylolisthesis. Conservative treatment is often recommend for 3 months before a return to play.

Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor-in-chief of the Journal of Orthopedics for Physician Assistants (JOPA).


  1. Purcell L, Micheli L. Low back pain in young athletes. Sports Health. 2009;1(3):212-222.
  2. Micheli LJ, Wood R.  Back pain in young athletes: significant differences from adults in causes and patterns. Arch Pediatr Adolesc Med. 1995;149:15-18.
  3. Panteliadis P, Nagra NS, Edwards KL, Behrbalk E, Boszczyk B. Athletic population with spondylolysis: review of outcomes following surgical repair or conservative management. Global Spine J. 2016;6(6):615-625.
  4. Selhorst M, Fischer A, Graft K, et al. Long-term clinical outcomes and factors that predict poor prognosis in athletes after a diagnosis of acute spondylolysis: a retrospective review with telephone follow-up. J Orthop Sports Phys Ther. 2016;46(12):1029-1036.
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