Scoliosis Surgery: Flatback Syndrome (Kyphosis)

When viewing the spine from the side (sagittal plane), we find the spine has two naturally occurring curves; a kyphotic curve in the thoracic (chest) area and a lordotic curve in the lumbar (low back) area. Curves are measured in degrees. The normal range for kyphosis is 20-45 degrees; lordosis is 30-65 degrees. If either or both curves are abnormally larger, they are addressed during surgery. Sometimes the main problem is in the sagittal (side) plane. Kyphosis or flatback syndrome (after Harrington rods are implanted) are examples.

Flatback syndrome was initially described in patients who had been treated with Harrington spinal instrumentation. This was the earliest spinal implant (instrumentation) to correct scoliosis. This instrumentation had a tendency to flatten the normal sway or lordosis in the lumbar spine, particularly when the fusion was taken down into the lower lumbar spine (L4 or L5). This system was utilized from the 1960s to the 1980s. With modern scoliosis implant systems and techniques, this problem is much less common. Patients treated with Harrington rods often do well for years or even decades. The spine can compensate for the "flattening" of lordosis with normal discs below the fusion. Eventually, as the discs below the fusion wear out (degenerate), the patient loses the ability to stand upright and develops pain.

Sagittal Plane Anatomy (showing natural Kyphosis (20-45°) and Lordosis (30-65°)

Cervical     Thoracic     Lumbar     Sacrum