spondyloptosis

Spondyloptosis is the most severe form of spondylolisthesis, defined as complete anterior dislocation of one vertebral body relative to the one below, corresponding to Meyerding grade V. It most commonly involves the lumbosacral junction, especially L5 over S1, but can occur at other levels. The condition arises from processes that disrupt the posterior elements or the pars interarticularis, including congenital/dysplastic anomalies, isthmic spondylolisthesis, degenerative changes, and, less commonly, traumatic injury. In children and adolescents it may be associated with a developing spine and deformity; in adults it presents with chronic back pain and sometimes neurologic signs.

Clinical features range from axial back pain and visible deformity with loss of lumbar lordosis to radiculopathy or signs of nerve compression. Neurologic impairment, including weakness or cauda equina symptoms, can occur with severe slippage.

Diagnosis relies on imaging. Plain radiographs show a complete anterior slip with Meyerding grade V. MRI or CT helps assess neural element compression, canal compromise, and the anatomy of the slip, and to plan surgery.

Management is individualized. Nonoperative care may be attempted for minimal symptoms but surgery is often required for instability or neurologic deficit. Surgical options include posterior instrumented fusion with reduction or in situ fusion; high-grade slips may require combined posterior and anterior approaches or osteotomies (such as a pedicle subtraction osteotomy) to achieve alignment and stable fusion while decompressing neural structures.

Prognosis improves with timely stabilization and fusion in symptomatic patients; prolonged dysfunction or severe neurologic injury portends a poorer outcome.