Spondylolisthesis is a displacement of a vertebra in which the bone slides out of its proper position onto the bone below it. Most often, this displacement occurs following a break or fracture.
Surgery may be necessary to correct the condition if too much movement occurs and the bones begin to press on nerves.
Other complications may include:
- Chronic back pain
- Sensation changes
- Weakness of the legs
- Temporary or permanent damage of spinal nerve roots
- Loss of bladder control
When a vertebra slips out of proper alignment, discs can be damaged. To surgically correct this condition, a spinal surgeon removes the damaged disc. The slipped vertebra is then brought back into line, relieving pressure on the spinal nerve.
Types of spondylolisthesis include:
- Dysplastic spondylolisthesis, caused by a defect in part of the vertebra
- Isthmic spondylolisthesis, may be caused by repetitive trauma and is more common in athletes exposed to hyperextension motions
- Degenerative spondylolisthesis, occurs with cartilage degeneration because of arthritic changes in the joints
- Traumatic spondylolisthesis, caused by a fracture of the pedicle, lamina or facet joints as a result of direct trauma or injury to the vertebrae
- Pathologic spondylolisthesis, caused by a bone defect or abnormality, such as a tumor
Symptoms may vary from mild to severe. In some cases, there may be no symptoms at all.
Spondylolisthesis can lead to increased lordosis (also called swayback), and in later stages may result in kyphosis, or round back, as the upper spine falls off the lower.
Symptoms may include:
- Lower back pain
- Muscle tightness (tight hamstring muscle)
- Pain, numbness or tingling in the thighs and buttocks
- Tenderness in the area of the vertebra that is out of place
- Weakness in the legs
- Stiffness, causing changes in posture and gait
- A semi-kyphotic posture (leaning forward)
- A waddling gate in advanced cases
- Lower-back pain along the sciatic nerve
- Changes in bladder function
Spondylolisthesis may also produce a slipping sensation when moving into an upright position and pain when sitting and trying to stand.
Causes and Risk Factors
Spondylolisthesis may appear in children as the result of a birth defect or sudden injury, typically occurring between the fifth bone in the lower back (lumbar vertebra) and the first bone in the sacrum (pelvis).
In adults, spondylolisthesis is the result of abnormal wear on the cartilage and bones from conditions such as arthritis, trauma from an accident or injury, or the result of a fracture, tumor or bone abnormality.
Sports that place a great deal of stress on bones may cause additional deterioration, fractures and bone disease, which may cause the bones of the spine to become weak and shift out of place.
A simple X-ray of the back will show any cracks, fractures or vertebrae slippage that are the signs of spondylolisthesis.
A CT scan or an MRI may be used to further diagnose the extent of the damage and possible treatments.
Treatment for spondylolisthesis will depend on the severity of the vertebra shift. Stretching and exercise may improve some cases as back muscles strengthen.
Non-invasive treatments include:
- Heat/Ice application
- Pain medicine (Tylenol and/or NSAIDS)
- Physical therapy
- Epidural injections
Surgery may be needed to fuse the shifted vertebrae if the patient has:
- Severe pain that does not get better with treatment
- A severe shift of a spine bone
- Weakness of muscles in a leg or both legs
Surgical process realigns the vertebrae, fixing them in place with a small rod that is attached with a pedicle screw, adding stability to the spine with or without the addition to an interbody (bone graft or cage) placed between the vertebra from the side or front.