Spondylolyse

Spondylolyse, also known as spondylolysis, is a defect or fatigue fracture of the pars interarticularis, the part of a vertebra between the superior and inferior articular processes. The condition most often involves the fifth lumbar vertebra (L5) and is the first lesion in the spectrum that can lead to spondylolisthesis if the posterior element becomes unstable.

The condition is most common in adolescents and young adults, particularly those engaged in sports that involve repetitive lumbar extension and rotation, such as gymnastics, football, and sprinting. It can be bilateral and may begin unilaterally before progressing or healing.

Clinical presentation typically includes chronic low back pain that is activity related and worsens with running, jumping, or hyperextension, often relieved by rest. Physical examination may reveal focal tenderness over the pars region and limited back extension, with otherwise normal neurologic findings.

Diagnosis is based on imaging and clinical features. Plain radiographs can miss early defects; oblique lumbar views may reveal the “collared Scottie dog” sign. Computed tomography (CT) provides a detailed view of the fracture line and is considered definitive. Magnetic resonance imaging (MRI) can detect bone marrow edema in acute fractures and assess adjacent soft tissue and other spinal pathology.

Management is usually nonoperative. This includes activity modification, bracing or a lumbar orthosis for several weeks, and a structured rehabilitation program emphasizing core stabilization. Return to sport is based on pain resolution and radiographic or MRI evidence of healing. Surgical options, such as pars interarticularis repair or fusion, are reserved for persistent pain, nonunion, or unstable spondylolisthesis despite adequate nonoperative treatment.

Prognosis is generally favorable in adolescents who heal with conservative care, with many returning to prior activity levels.