Characteristics Associated With Active Defects in Juvenile Spondylolysis.

Diagnosis is crucial in early-stage lumbar spondylolysis, as osseous healing can occur with conservative treatment. Single-photon emission computed tomography (SPECT) traditionally has been the most sensitive modality for diagnosing active (early) spondylolysis. More recently, high signal change (HSC) in the pedicle or pars interarticularis on fluid-specific (T2) magnetic resonance imaging (MRI) has been shown to be important in the diagnosis of early spondylolysis. We conducted a study to determine the clinical and radiographic characteristics associated with the diagnosis of early or active spondylolysis. Fifty-seven patients with a total of 108 pars defects and a mean age of 14.6 years were retrospectively identified. Defects with a positive SPECT or HSC on T2 MRI were classified as active. There were 49 active and 59 inactive defects. The active and inactive groups did not differ in age, body mass index, symptom duration, lumbar lordosis, pelvic incidence, slip percentage, or laterality. There was a difference in sex (35 vs 19 males; P < .0001) and presence of listhesis (16 vs 35; P = .006). Active or early juvenile spondylolysis appears to be associated with male patients and the absence of listhesis, which may be important in identifying patients with a higher potential to experience osseous healing with nonoperative treatment.