What Is Lumbar Flatback?
Lumbar lordosis is the curve in the low back when the body is viewed from the side and is usually 40-50 degrees. This lumbar lordosis allows one to stand up straight. If there is not enough lordosis, then one leans forward when walking. This lack of lumbar lordosis is called lumbar flatback. Lumbar flatback or loss of lordosis may occur as one ages and loses height of the lumbar discs. Another common cause of loss of lumbar lordosis is lumbar fusion surgery in which the spine is fused flat or without preservation of the normal lumbar lordosis.
Lumbar Flatback Diagnosis
Lumbar flatback is diagnosed by watching a person walk. The person leans forward and looks like a skier leaning forward after launching from a ski jump. Lumbar flatback may be confirmed by obtaining a standing full-length x-ray of the spine and measuring the lumbar lordosis. If less than 40 degrees, the patient has lumbar flatback. Not all persons with lordosis less than 40 degrees lean forward. It is necessary to compare the lumbar lordosis to the tilt of the pelvis which is termed pelvic incidence. For a person to walk upright it is necessary for the lumbar lordosis to equal the pelvic incidence.