Spondylolysis is frequently missed by MRI in adolescents with back pain.

PURPOSE: Magnetic resonance imaging (MRI) is often used in the evaluation of lower back pain in adolescents. The purpose of our study is to report on the frequency of MRI missing spondylolysis in adolescents with back pain in a pediatric orthopaedic practice.

METHODS: A retrospective review of all patients with a diagnosis of spondylolysis who presented from January 2000 to March 2010 was performed. All patients were evaluated at a single institution by the senior author. Inclusion criteria were patients with spondylolysis confirmed on computed tomography (CT) or plain film that also received an MRI.

RESULTS: Eleven patients with spondylolysis had an MRI performed. The mean age of the study patients was 14.2 years (range 10-17). The diagnosis of spondylolysis was missed in the MRI radiology reading in 7 out of 11 (64 %) studies.

CONCLUSIONS: MRI missed a spondylolysis in over half of the adolescents in this consecutive series. In patients with a history or physical findings suggestive of spondylolysis, such as localized pain of the lumbar spine with back extension, further radiographic evaluation should be considered, even if an MRI is negative.

LEVEL OF EVIDENCE: III, retrospective review.