Flat Back Syndrome

The lumbar part of the spine, which is where the spine is joined to the pelvis, normally curves slightly backwards. This type of a curve is called "lordosis", and it helps the spine to carry the weight of the trunk, arms, and head in a balanced and well-aligned nature. The thoracic part of the spine, which is where the ribs attach to the spine, normally curves slightly forward, and this curvature is called "kyphosis". Both of these curves help to balance the loads that are carried by the spine.

"Flat back syndrome" refers to the loss of the normal lordotic curvature of the lumbar spine or the loss of the kyphotic curvature of the thoracic spine, so that the spine becomes straight. When this happens, the patient often appears stooped forward and it is often difficult for them to stand up straight. Patients can develop a painful flat back deformity as the result of degenerative arthritis of the spine, or as a consequence of a previous spinal fusion operation.

Flat back syndrome describes a number of symptoms and changes in the normal alignment of the spine, including chronic pain in the muscles of the back, abnormal posture, difficulty with certain activities, and cosmetic concerns. Many patients with a significant flat back deformity require a cane or a walker to assist them when walking, because they are stooped forward, and their weight is not centered over their pelvis and legs. It can be a source of significant pain, disability, and frustration.

Historically, flat back syndrome was most commonly associated with spinal fusion surgery that was done with the use of the Harrington Rod Spinal System. The Harrington rod technique was used during the 1960s through the early 80s and was one of the first techniques used in surgical correction of scoliosis. The Harrington rod technique primarily used the principle of distraction, or separation of the ends of the curve along a straight rod, in order to correct the abnormal side-to-side curvature of scoliosis. Unfortunately, this also straightened out the normal front to back curvature of the segment of the spine that was fused, resulting in a flat back deformity.

Today, surgeons are often able to correct scoliosis while still preserving as much of the normal alignment of the spine as possible. This is largely the result of advances in the techniques and types of instruments that are used to correct scoliosis. Although the number of patients who develop a flat back deformity after scoliosis surgery has decreased, it is sometimes impossible to prevent this situation from occurring. The correction of a scoliosis curve requires corrections in many different planes, including side-to-side curves, front to back curves, and rotational abnormalities.