Flatback and Related Syndromes

Flatback syndrome is a condition related to poor spinal alignment which leads to symptoms such as back pain, bad posture with hips and knees flexed while standing and a tendency to stoop forward at the end of the day with increasing pain and fatigue in the back and legs. This syndrome is mostly related to previous scoliosis surgery and particularly the placement of Harrington rods extending to the lumbar spine.

It has become clear over the last decade that a direct relationship exists between operations for scoliosis spinal fusion with correction of the deformity by Harrington rod (and technique) as an adolescent and the development of flatback as an adult. In fact before the Harrington technique, which was developed in the mid sixties, scoliosis was described as a deformity that affected the spine as a rotational deformity evolving progressively into a twisted shape similar to a spiral staircase. This abnormal deformation of the spine leads to a rib cage deformity, which is apparent on the patient as a hump when seen from the back.

Historically, with the development of Xray techniques, scoliosis was evaluated on patients by obtaining chest films by postero-anterior exposure. In the sixties it became routine to evaluate scoliosis on a standing Xray with a similar exposure showing a projection of the spine on antero-posterior films. We now know that this radiographic technique does not provide sufficient information on the complex shape of the spine. Spinal column evaluation must be at least made on two films one antero-posterior and the other lateral.

It is important to note that in a healthy spine there are several normal curvatures of the spine seen from the side (sagittal view) which are balanced such that the head remains centered over the hips when standing. In scoliosis the local contour and balance of the spine can be altered. In planning surgical treatment one must carefully consider the effects on spinal balance to ensure long-term success. As a result of the limited understanding of scoliosis based on Xrays in the frontal plane only, oversight of the sagittal plane may lead to treatment of the frontal plane curvature only. Many patients treated in the past had a correction of their scoliosis which did not disturb the overall balance of their spine. In some patients surgical treatment with long fusions (and instrumentation in distraction) for scoliosis correction, problems have developed with spinal imbalance and with that a progressive development of a flatback (fig. 3,4 & 5).

Some degrees of spinal imbalance may be well tolerated by a patient. This imbalance can be adjusted for by spinal segments which are still mobile (not included in the fusion). However, when significant malalignment has been created these mobile segment of the spine will gradually 'wear out' with development of ligament and disc degeneration. As a result back pain, fatigue, and progressive deterioration of endurance and posture can develop. Neck pain may also be present due to the poor posture requiring additional strain on the neck in order to maintain level vision. In severe cases the entire upper spine may become deformed (swan neck deformity).

The treatment of flatback can be challenging. In mild cases of malalignment the intitial treatment may focus on physical therapy and functional rehabilitation of the back, buttock and leg muscles. In moderate and severe cases, a non-operative approach may not be sufficient. The treatment options may then include surgery in order to obtain a correction of the spinal alignment and a stable, well balanced spinal column. If there are levels of the lumbar spine that have not been fused in the intitial scoliosis surgery but have become very degenerated, then surgery may include a fusion of additional spinal levels in order to obtain balance and a solid, painless spine. If it is not possible to obtain adequate spinal re-alignment through fusing additional levels, then the previous fusion may have to be cut (osteotomy) in order to obtain correction through the old fusion. The surgery in such a setting is very difficult, and only very experienced teams should perform such operations. The risks can be significant and the complication rates, even in the best of hands are not low. With a good realignment of the spine, excellent results are possible.

Frequently Asked Questions

Reference:

1. Farcy, J.P.C., M.D.; Schwab, F., M.D.: Management of Flat Back and Related Kyphotic Decompensation Syndromes. Spine Vol.22, No.20: 2452-2457, 1997.
2. Farcy, J.P.C., M.D.; Schwab, F.: Realignment for Flatback and Associated Syndromes. Annual meeting of the North American Spine Society. October,1995. Washington, D.C.
3. Schwab, F.J. ; Klein, J.R.; Farcy, D.; Hoffman, B.; Farcy, J-P.C.; Schechter, C.: Sagittal Plane Pelvic Rotation: A Compensatory Mechanism in Spinal Deformity. Annual Meeting of the Scoliosis Research Society. September, 1999.