In this series of blog posts, we have been reviewing spine-related musculoskeletal conditions. The next condition we will be looking at is spondylolisthesis.
Definition: Occurs when a vertebra (typically in the lumbar spine) slides forward over the vertebra beneath it.
Overview: The vertebrae in the spinal column are linked together by small joints (facets) that permit the spine to bend forward (flexion) and backward (extension) while limiting rotational movement. Spondylolisthesis occurs when a joint defect in the vertebrae (resulting from either a stress fracture or degeneration) permits one vertebra to slip forward on the one beneath it.
Spondylolisthesis is most common in the lower back, though in rare cases it can occur in the cervical spine. It most frequently occurs at the L4-L5 and L3-L4 levels of the lumbar spine.
There are two types of spondylolisthesis: isthmic spondylolisthesis (IS) and degenerative spondylolisthesis (DS). IS occurs when a stress fracture of a small bone called the pars interarticularis permits a vertebra to slip forward over the vertebra below it. IS is rare, and is most common in young children who participate in sports that put repeated stress on the lower back.
DS is far more common and most regularly occurs among people over the age of 50. DS is a result of the gradual breakdown of the intervertebral discs and the facet joints in the spine. As the discs lose volume, more stress and pressure is placed on the facet joints. As the facet joints begin to degrade under the increased wear and pressure, they may allow too much flexion and cause a vertebra to slip forward over the vertebral body below it.
The slippage can place direct pressure on the spinal cord (spinal stenosis) and on the nerve roots exiting the spinal column (foraminal stenosis).
Symptoms: Lower back pain, leg pain (especially “running down” the leg), and sciatic pain are common. Numbness or weakness often occurs in one or both legs. Leg/back pain that is worse when bending over or twisting is common, as is pain that is worse standing than sitting.
Causes: Degenerative disc disease is a common cause of spondylolisthesis. As we discussed above, when the intervertebral discs lose volume the spinal column becomes more compressed. Without the shock absorption of the discs, more pressure is exerted on the facet joints. This pressure and wear accelerates the degradation of the facets and allows for the increased flexion in the spine that can lead to vertebral slippage. As clinical dentistry has moved from a standing profession to a seated one, dentists are at a higher risk for lower back conditions like spondylolisthesis. Axial loading (the weight of the body compressing the spine vertically) on the lumbar spine is significantly higher in a seated position than it is standing.
Diagnosis: X-rays are used to determine whether or not a vertebra is out of place. If the displaced vertebra is putting pressure on the spinal cord or nerve roots, a CT scan may be ordered to identify the severity of the problem.
Treatment: As with many other conditions discussed in this series, conservative treatment may include some combination of physical therapy, exercise, strength training, manual manipulation, and medication. Epidural steroid injections are sometimes prescribed for those in severe pain. Spinal fusion surgery is sometimes used for severe pain that has not been successfully treated with less invasive treatment. Typically, a posterior fusion with a pedicle screw implementation is used, but a surgeon may also recommend a spinal fusion done from the font of the spine simultaneously.
Our next post in the series will examine disc bulge, disc herniation, and disc protrusion.
These posts are for informative purposes only and should not be used as a substitute for consultation with and diagnosis by a medical professional. If you are experiencing any of the symptoms described below and have yet to consult with a doctor, do not use this resource to self-diagnose. Please contact your doctor immediately and schedule an appointment to be evaluated for your symptoms.
1. Spine-health, https://www.spine-health.com/.
2. Mayo Clinic, http://www.mayoclinic.org/.
3. The Neurological Institute of New York,
4. John Hopkins Medicine, http://www.hopkinsmedicine.org/.
5. WebMD, http://www.webmd.com/.