Flatback Deformity

What Is Flatback Syndrome?

If you have been diagnosed with “flatback syndrome”, you likely are having a difficult time standing straight and have a tendency to lean forward when you are standing or walking. The low back (or lumbar spine) normally has an “arch” when viewed from the side. This is called “lumbar lordosis”. This arch in the low back is what allows humans to stand in an upright posture. If, for whatever reason, this arch is lost, then it becomes increasingly difficult to stand straight. The term “flatback” refers to this condition. The term “flat” implies that the arch is no longer an arch, but rather a flat lumbar spine.

What Causes Flatback Syndrome?

There are several causes of flatback syndrome, the most common being previous lumbar fusion surgery. The following are some examples of patients who present with this condition:

  • Patients who have had one or more prior back surgeries. With each surgery (or fusion), patient may have lost just a little bit of that “arch” in the lumbar spine. This does not mean the surgeries were not properly performed. The fact is that it can be difficult to create the arch in the spine when it has been lost through degeneration and wear and tear of the discs. For example, a patient may have had fusion of L4-5 and L5-S1 a few years prior, and then developed pinched nerves at the level above (at L3-4), and had another fusion at this level. With each operation, patient may have lost a little bit of that arch which becomes significant when you add all the levels. This patient may have difficulty standing straight because his spine is fused in a “flat” position
  • Patients who have had previous Harrington rod instrumentation down to L4 or L5 for scoliosis when they were teenagers. These patients likely did very well through their 20’s and 30’s, and then develop problems with pain in their 40’s and 50’s. The reason for their pain and inability to stand straight is the flatback deformity they have developed as a result of the Harrington rods
  • Patients who have never had any back surgery, but who have severely degenerated discs. With collapse and breakdown of each disc, a little bit of that arch is lost, and when you have multiple discs wear out, patient may lose the arch entirely and develop a “flatback”
  • Patients with Ankylosing spondylitis

Diagnosis of Flatback Syndrome

The diagnosis of this condition is fairly straightforward. Most patients complain of low back pain and increasing difficulty maintaining an upright posture. The low back pain is related in part to fatigue of the low back muscles. Fatigue of the thighs and hips occurs with standing as patients try to compensate for the flatback by bending their knees. Patients typically have limited standing and walking tolerance due to pain. Some patients require a walker for support. X-rays show loss of lumbar lordosis, and there are several measurements that are taken to diagnose this problem on the x-rays.

Treatment of Flatback Syndrome

Once flatback syndrome has developed and patient has low back pain and difficulty standing straight, the only effective treatment is surgery. Unfortunately, physical therapy and injections have not been shown to be effective for this problem.

Surgery for flatback syndrome is successful in treating the pain and disability, and the results can be very gratifying. The surgery is fairly extensive, and requires reconstruction of the spine to recreate the lumbar lordosis (or arch) that has been lost. The specifics of the surgery vary depending on patient anatomy and cause of the flatback deformity. Different techniques are available, each having its own advantages and disadvantages. The most common technique is called a “pedicle subtraction osteotomy”.