Sagittal Imbalance

About Sagittal Imbalance

Sagittal imbalance is a front to back imbalance occurring in the spine. Typically the spine has compensatory gentle curves, one in neck (cervical), the thoracic (middle), and the lumbar (lower) spine. These curves work together to keep the body’s center of gravity aligned. If one of these curves becomes too pronounced or flat the spine will become out of balance.

There are two common types of sagittal imbalance, flat back syndrome and kyphosis. Flat back syndrome affects the lumbar spine, where the normal curvature is decreased, pitching the center of gravity too far forward. Kyphosis is an exaggerated forward curvature that commonly affects the thoracic spine, also forcing the patient to lean forward. Some kyphotic deformities create a hunchback.

This deformity can gradually occur over time with age but can also be associated with previous spinal fusion surgery. Some other causes include:

  • Degenerative conditions – these cause wear and tear on the spine
  • Traumatic injury
  • Congenital birth defect
  • Osteoporosis
  • Ankylosing spondylitis – type of arthritis
  • Neuromuscular conditions (spina bifida, cerebral palsy, muscular dystrophy)

Common Symptoms of Sagittal Imbalance

Common symptoms of sagittal imbalance include:

  • Lower back pain
  • A sensation of constantly leaning forward
  • Difficulty looking straight ahead while standing
  • Trouble walking
  • Fatigue
  • Difficulty completing daily tasks
  • Weakness/numbness/pain (if a spinal nerve is compressed)

Diagnosis of Sagittal Imbalance

There are a few different imaging tests that can be used to properly diagnose sagittal imbalance. These tests include:

  • X-ray – imaging from X-rays can be used to see any bone abnormalities or spinal dislocation that may be causing a pinched nerve. Often an X-ray of the entire spine is obtained to get a global view of the spine.
  • MRI scan – shows soft tissue (discs, spinal cord, and nerves) clearly
  • CT scan – uses x-ray images and a computer to produce detailed pictures of the spine bones and surrounding structures

Treatment of Sagittal Imbalance

The varying causes of sagittal imbalance make treatment for each case different. However the overall goal of treatment is the same for each case: reestablish the sagittal spinal balance. Usually surgery aims to add lordosis to the lumbar spine, take away kyphosis from the thoracic spine, or both. Most procedures consist of three parts.

  1. Correct the spinal deformity – this usually happens by removing a bone to loosen the spine. Extent and removal depends of the location and type of spinal deformity
  2. Spinal fixation – the spine is then fixed into place and secured with screws, rods, and hooks
  3. Spinal fusion – bone graft material will then be implanted to help make the spine more stable on a permanent basis.