Spondylolisthesis occurs when one of the vertebrae in the spine slips out of position.
Usually, this vertebra has slid forward over the vertebra directly below it. Spondylolisthesis is most common in the lower back, and occurs more often in adolescents and adults.
Due to the varying degrees and causes of the misalignment, spondylolisthesis is broken down into types and grades. The six main types are based on the cause of the spondylolisthesis.
Type I – In some cases, people are born with spondylolisthesis. A child may also develop the condition naturally during his or her developmental years. In both cases of Type I spondylolisthesis, a child may not experience any symptoms or problems until later in life.
Types II – In Type II, the most common type, there is a problem with a section of the vertebra called the pars interarticularis. Type II is further broken down into the following subtypes:
- Type IIA involves many microfractures caused from overuse and hyperextension.
- Type IIB involves many microfractures that do not fracture completely and heal with extra bone in place. The extra bone causes stretching and misalignment.
- Type IIC is a complete fracture that has been caused by trauma. A sports injury or being in a car accident may cause Type IIC.
The fractures from Type II only become spondylolisthesis if they cause the vertebra to slip forward.
Type III – Type III is associated with aging and the natural wear and tear on a person’s body.
Type IV – Type IV is a fracture that occurs anywhere in a vertebra except in the pars interarticularis region.
Type V – Type V involves tumors on the vertebrae that push on the bones and cause weakness.
Type VI – Type VI is an uncommon spondylolisthesis caused by weakening of the back due to surgery.
Spondylolisthesis is further classified into grades, according to how far out of place the vertebra is. The grades are:
- Grade 1: 25 percent of the vertebral body has slipped forward. This is the lowest grade.
- Grade 2: Between 25-50 percent of the vertebral body has slipped forward.
- Grade 3: Between 50-75 percent of the vertebral body has slipped forward.
- Grade 4: Between 75-100 percent of the vertebral body has slipped forward.
- Grade 5: The vertebral body has completely fallen off and looks detached.
A person may have had spondylolisthesis since birth and never experienced any symptoms from it. It is common for a person to develop symptoms as they age, however.
Symptoms can range in severity from non-existent to a loss of urination and bowel movement control in more severe cases.
Some of the most common symptoms include:
- difficulty walking or running
- pain in the lower back or buttocks
- pain that travels from the back down one or both legs
- weakness in one or both legs
- pain in lower back and legs that is aggravated by movement or twisting
- tight hamstrings
- increased inward curve of the spine, known as lordosis
The causes of spondylolisthesis vary. Some people are born with a defective vertebra that may not be identified until much later in life. Others experience an injury to the back either repeatedly or on one occasion only.
Knowing the cause can help a doctor determine the type of spondylolisthesis a person has, as well as help determine the best treatment.
Typical causes include:
- fractures from injury
- joint injury from arthritis or illness
- degeneration from overuse or aging
- birth defect
- spondylolysis, a defect or fracture in the pars interarticularis region
In many cases, a person may not know they have spondylolisthesis as they may have no symptoms. In these cases, a doctor might discover the condition during an exam for something else entirely.
Diagnosis starts with a physical exam and questions about what kind of pain or numbness the person is experiencing. If a doctor suspects spondylolisthesis, they will order an X-ray of the back.
Visual examination of the X-ray is often enough to determine if a person has spondylolisthesis, as well as to decide the grade.
In some cases, a doctor may order additional imaging to find the exact locations of the fractures to help guide the individual’s treatment.
The cause of spondylolisthesis can often be found by the initial questions about when and how the symptoms started.
Treatment options include at-home care, therapies, and possible surgery.
A person can start treatment at home through a variety of methods, including using over-the-counter medication for pain relief.
In cases where overuse has caused the spondylolisthesis, a person should stop any activities that aggravate the pain. Additionally, someone who is overweight might want to consider losing weight, which may help alleviate their symptoms.
A doctor can prescribe additional pain relief and anti-inflammatory medications if necessary. They may also order physical therapy.
Physical therapy will help a person build up core muscles in the midsection of their body and back. Physical therapy can also include stretching to help relieve pain and improve flexibility.
In more extreme cases, a doctor might recommend surgery. Surgery is usually reserved for cases where there is spinal damage, the vertebra continues to slip, or the pain is extreme.
Surgery can remove excessive bones or fuse the vertebrae back together. If surgery is used, a person will need to take the appropriate steps to recover from the procedure afterward.
Some people may go their whole lives without knowing they have spondylolisthesis. Others may find out during an unrelated visit to the doctor’s office or when being diagnosed with another disorder.
For those who experience pain, numbness, or other symptoms, the overall outlook is still very good. Most people can manage their spondylolisthesis with a combination of therapies and medication.
In the most extreme cases, a person may consider surgical options. After surgery, the individual can expect a recovery period lasting several weeks or months before being able to return to normal activities.