Flatback Syndrome (Kyphosis): Possible Scoliosis Surgery Complication
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.
What Is Kyphosis? How Is It Related to Flatback Syndrome?
When viewing the spine from the side (sagittal plane), we find the spine has 2 naturally occurring curves:
- a kyphotic curve in the thoracic (chest) area
- a lordotic curve in the lumbar (low back) area
Spinal curves are measured in degrees. The normal range for kyphosis is 20-45 degrees; lordosis is 30-65 degrees.