Spondylolisthesis is a condition in which one vertebra slips forward over the one below it. Spondylolisthesis is a fairly common cause of lower back pain and leg pain in younger adults (age 30 to 50), and degenerative spondylolisthesis is a fairly common cause of pain in older adults (age 50 and up). The most common symptoms are lower back pain and/or leg pain that limits activity level.

Degenerative Spondylolisthesis

Degenerative spondylolisthesis is Latin for "slipped vertebral body," and it is diagnosed when one vertebra slips forward over the one below it. This condition occurs as a consequence of the general aging process in which the bones, joints, and ligaments in the spine become weak and less able to hold the spinal column in alignment.

Degenerative spondylolisthesis is more common in people over age 50, and far more common in individuals older than 65. It is also more common in females than males by a 3:1 margin.

A degenerative spondylolisthesis typically occurs at one of two levels of the lumbar spine:

The L4-L5 level of the lower spine (most common location)

The L3-L4 level.

Degenerative spondylolisthesis is relatively rare at other levels of the spine, but may occur at two levels or even three levels simultaneously. While not as common as lumbar spondylolisthesis, cervical spondylolisthesis (in the neck) can occur. When degenerative spondylolisthesis does occur in the neck, it is usually a secondary issue to arthritis in the facet joints.

Degenerative Spondylolisthesis Causes

Every level of the spine is composed of a disc in the front and paired facet joints in the back. The disc acts as a shock absorber in between the vertebrae, whereas the paired facet joints restrain motion. They allow the spine to bend forwards (flexion) and backwards (extension) but do not allow for a lot of rotation.

As the facet joints age, they can become incompetent and allow too much flexion, allowing one vertebral body to slip forward on the other.

Degenerative spondylolisthesis is diagnosed by a spine specialist through a 3-step process:

Medical History – primarily a review of the patient’s symptoms and what makes the symptoms better or worse.

Physical Examination – the patient is examined for physical symptoms, such as range of motion, flexibility, any muscle weakness or neurological symptoms.

Diagnostic Tests – if a spondylolisthesis is suspected after the medical history and physical exam, an X-ray may be done to confirm the diagnosis and/or rule out other possible causes of the patient’s symptoms. Based on the results of the X-ray, further tests may be ordered, such as an MRI scan, to gain additional insights.

Unlike isthmic spondylolisthesis, the degree of the slip of a degenerative spondylolisthesis is typically not graded as it is almost always a grade 1 or 2.

In cases of degenerative spondylolisthesis, the degenerated facet joints tend to increase in size, and enlarged facet joints then encroach upon the spinal canal that runs down the middle of the spinal column, causing lumbar spinal stenosis.

Degenerative Spondylolisthesis Symptoms

As the facet joints in the spine degenerate they often get larger, which can encroach upon the spinal canal that runs down the middle of the spinal column, resulting in spinal stenosis. The symptoms of a degenerative spondylolisthesis are very commonly the same as that of spinal stenosis.

The main symptoms of degenerative spondylolisthesis include:

Lower back pain and/or leg pain are the most typical symptoms of degenerative spondylolisthesis. Some patients do not have any back pain with degenerative spondylolisthesis and others have primarily back pain and no leg pain.

Patients often complain of sciatic pain, an aching in one or both legs, or a tired feeling down the legs when they stand for a prolonged period of time or try to walk any distance (called pseudoclaudication).

Generally, patients do not have a lot of pain while sitting, because in the sitting position the spinal canal is more open. In the upright position, the spinal canal gets smaller, accentuating the stenosis and pinching the nerve roots in the canal.

Patients typically have tight hamstring muscles (the muscles in the back of the thigh) decreased flexibility in the lower back, and difficulty or pain with extension (arching the back backwards).

The nerve root pinching can lead to weakness in the legs, but true nerve root damage is rare.

There is no spinal cord in the lumbar spine, so even for patients with severe pain, there is no danger of spinal cord damage. If the spinal stenosis becomes very severe, or if the patient also has a disc herniation, they can develop cauda equina syndrome where there is progressive nerve root damage and loss of bladder/bowel control. This clinical syndrome is very rare, but if it does occur it is a medical emergency.

Degenerative Spondylolisthesis Treatment

While there is a wide range of non-surgical treatment options (such as pain medications, ice or heat application) that may help with some of the pain of a degenerative spondylolisthesis, there are essentially four categories of treatment options a patient will ultimately have to choose from.

Activity Modification: Patients can modify their activities so they spend more time sitting and less time standing or walking. Activity modification generally includes:

  • A short period of rest (e.g. one to two days of bedrest or resting in a reclining chair)
  • Avoiding standing or walking for long periods
  • Avoiding active exercise
  • Avoiding activities that require bending backwards.

If activity modification substantially reduces the patient’s pain and symptoms, this is an acceptable way to manage the condition long term. Simple self care can assist in this approach, such as application of cold packs and or heating pads and/or taking appropriate over-the-counter pain relievers, such as ibuprofen and/or acetaminophen, after walking or any strenuous activity.

For patients who want to be more active, stationary biking is a reasonable option, as activity in the sitting position should be tolerable. Another option is pool therapy – physical therapy done while in a warm swimming pool – as the water provides support and buoyancy and the patient is allowed to exercise in a flexed forward position.

Many patients also benefit from controlled, gradual exercise and stretching as part of a physical therapy program to maintain and/or increase range of motion and flexibility, which in turn tends to alleviate pain as well as help the patient maintain their ability to function in everyday activities.

Manual Manipulation: Chiropractic manipulation provided by chiropractors, or manual manipulation provided by osteopathic physicians, physiatrists or other appropriately trained health professionals, can help reduce pain by mobilizing painful joint dysfunction.

Epidural Injections: For patients with severe pain, especially leg pain, epidural steroid injections may be a reasonable treatment option. The injections are effective in helping to curb pain and increase a patient’s function in up to 50% of cases. If an epidural steroid injection does work to relieve the patient’s pain, it can be done up to three times per year. The length of time that the lumbar epidural injection can be effective is variable, as the pain relief can last one week or a year.

Surgery: Surgery for degenerative spondylolisthesis is rarely needed, and most patients can manage their symptoms with the above nonsurgical options. Surgery may be considered if the patient’s pain is disabling and they would likely be able to function better and be more active with less pain. Surgery is also indicated if the patient is experiencing progressive neurologic deterioration.The goals of surgery are to realign the affected segment of the spine to alleviate pressure on the nerve and provide stability to the area.

Surgery for Degenerative Spondylolisthesis

Surgery for a degenerative spondylolisthesis usually includes two parts, done together in one operation:

  • A decompression (also called a laminectomy)
  • A spine fusion with pedicle screw instrumentation
  • Decompression surgery (e.g. a laminectomy) alone is usually not advisable as the instability is still present and a subsequent fusion will be needed in up to 60% of patients. A 1991 randomized controlled study of fusion with and without pedicle screw instrumentation and found the fusion rates were much higher in the patients with instrumentation, but the clinical results were about the same. However, when these same patients were followed up on 10 years later, the patients with a solid fusion ultimately fared significantly better than those that had not fused. It is a difficult surgery to recover from as there is a lot of dissection. The hospital stay typically ranges from one to four days. It can take up to a year to fully recover. Usually, most patients can start most of their activities after the fusion has had three months to heal. Once the bone is fused, then the more active the patient is, the stronger the bone will become.

    Potential Benefits of the Surgery

    Spinal fusion surgery for a degenerative spondylolisthesis is generally quite successful, with upwards of 90% of patients improving their function and enjoying a substantial decrease in their pain.

    Potential Risks and Complications

    There are numerous risks and possible complications with surgery for degenerative spondylolisthesis and they are basically the same as for any fusion surgery. There are risks of non union (nonfusion, or arthrodesis), hardware failure, continued pain, adjacent segment degeneration, infection, bleeding, dural leak, nerve root damage and all the possible general anesthetic risks (e.g. blood clots, pulmonary emboli, pneumonia, heart attack or stroke). Most of these complications are rare, but increased risks can be seen in certain situations. Conditions that increase the risk of surgery include smoking (or any nicotine intake), obesity, multilevel fusions, osteoporosis (thinning of the bones), diabetes, rheumatoid arthritis, or prior failed back surgery. Since degenerative spondylolisthesis is a condition that disproportionately affects individuals over age 60 or 65, the surgery does present some additional risk. Surgical risk is more directly related to the overall health of a patient and not his or her absolute age. Particularly in patients who have multiple medical problems, surgery can be very risky. For some patients, even if non-surgical treatments have failed to alleviate their symptoms, surgery may present too much risk, and intermittent epidural injections combined with activity modification may be their best option. After a fusion procedure, degeneration of the spinal segment adjacent to the fusion is possible. In an attempt to alleviate transferring extra stress to the next segment, there are many different devices currently being studied that hold the promise of being able to replace the function of the facet joint without having to include a fusion procedure. It is too early to determine whether or not the results of these newer technologies are better or worse than the standard fusion procedure.