Definition & Overview
Adjacent segment disease (ASD) is a spinal disorder that may develop after spinal fusion (e.g., instrumentation, bone graft). Although ASD is widely known to be a potential complication of spinal fusion, it can also be caused by natural degenerative changes that occur in the spine due to aging.
Symptoms & Characteristics
ASD may produce symptoms similar to those that led to the original spine surgery. Common indicators include:
- Low back pain
- Pain that radiates from your low back down into one or both legs and/or feet
- Neurological symptoms (tingling, numbness, or weakness) in your lower extremities
- Pain that radiates from your neck down into your shoulders, arms, and/or hands
- Pain while walking and/or difficulty standing
Causes
Adjacent segment disease generally stems from two primary factors:
1. Aging
There is a natural degenerative process that takes place in the spine. As we age, the cushioning discs in our spine dry out and the disc space gradually "collapses" and loses its normal height.
2. Fusion Surgery
Fusing or locking bones together is thought to potentially accelerate degeneration by increasing the stress and motion above and below the fusion level. However, not everyone with a spine fusion develops ASD.
Treatment Options
Non-Surgical: Milder forms of ASD that are not causing spinal instability, severe pain, or nerve problems may be treated non-surgically. Physical therapy may help improve body mechanics, and medications and spinal injections can help ease inflammation and pain.
Surgical: Severe cases of ASD—those that compromise the stability of your spine and/or nerve health—may require a second surgery. In most cases, this will be an extension of the fusion.