Spondylolysis

M43.00 identifies acquired spondylolysis — a defect or stress fracture through the pars interarticularis of a vertebra — when the operative spinal level is not documented or specified in the medical record.

Acquired spondylolysis (a defect or stress fracture of the vertebral arch) localized to the occipito-atlanto-axial region — the bony junction involving the occiput, atlas (C1), and axis (C2).

Acquired defect or stress fracture of the pars interarticularis in one or more cervical vertebrae, classified as a deforming dorsopathy of the cervical spine region.

Spondylolysis localized to the cervicothoracic junction (C7-T1 transition zone), representing a defect or stress fracture of the vertebral pars interarticularis at that spinal segment.

Acquired defect or stress fracture of the posterior vertebral arch (pars interarticularis) localized to the thoracic spine, classified under deforming dorsopathies.

Spondylolysis localized to the thoracolumbar junction, representing a defect or stress fracture of the pars interarticularis at the T12-L1 level.

Defect or fracture of the pars interarticularis at the lumbar level, without vertebral slippage — coded as acquired spondylolysis confined to the lumbar spine region.

Acquired defect or stress fracture of the pars interarticularis at the lumbosacral junction (L5-S1 level), classified under other deforming dorsopathies. Does not include congenital spondylolysis (Q76.2) or spondylolisthesis (M43.1-).

Defect or stress fracture of the posterior vertebral arch (pars interarticularis) located specifically at the sacral and sacrococcygeal spinal levels, classified as an acquired deforming dorsopathy rather than a congenital anomaly.

Spondylolysis involving two or more distinct spinal regions simultaneously, captured under a single billable code when documentation confirms defects at multiple vertebral levels rather than a single anatomical site.