What Is Flatback Deformity?

When the lower back (lumbar spine) loses its normal swayback curve (lordosis) this can result in FLATBACK DEFORMITY. The main symptoms of Flatback Deformity are difficulty standing up straight often associated with low back or leg pain. Typically, these symptoms get worse towards the end of the day as the muscles supporting the back and legs fatigue. In an attempt to adjust for the Flatback Deformity, patients may extend their hips by rotating the pelvis backwards and/or bend their knees causing pain in the buttocks or in the front of the thighs. Flatback Deformity may be associated with nerve trouble resulting in sciatica or weakness/numbness of the legs. The pain and stooped posture may become disabling, requiring increasing pain medications and limiting day-to-day activities.

There are many causes of Flatback Deformity. The original description was following surgery for Scoliosis with Harrington rods that stretched out the normal swayback in the lumbar spine when the rods extended to the lower lumbar spine. With current scoliosis techniques, this problem is much less common.

Other causes of Flatback Deformity include:

• prior surgery in which the spine was fused with inadequate curve
• loss of curve following spinal decompression surgery (post-laminectomy kyphosis)
• multiple levels of severe disc degeneration and collapse
• vertebral compression fractures
• other less common conditions such as Ankylosing Spondylitis and Parkinson’s Disease.

Non-surgical treatment includes physical therapy and anti-inflammatory medications. Muscular rehabilitation and exercise programs may help in some patients, however, if the deformity is significant, surgery may be necessary. Surgery is aimed at restoring the normal alignment and often involves a spinal osteotomy. An osteotomy is a wedge shaped removal of bone that is used to correct the abnormal alignment.

1. A) Side view of the spine showing the area of bone resection in pink.
2. B) The improved curvature after the osteotomy is closed.

BEFORE                                 AFTER

A) Preoperative photo of patient with post-fusion flatback.

B) Preoperative x-ray of the same patient showing screws and rods with a flatback deformity.

C) Postoperative photos of the same patient one year after surgical correction of the flatback deformity.

D) Postoperative x-ray of the same patient.

For more information:

https://www.srs.org/patients-and-families/conditions-and-treatments/adults/other-spine-deformities-and-conditions