Spondylolisthesis occurs when one of the vertebrae in the spine has slid forward over the vertebra directly below it. Symptoms can include difficulty walking and lower back pain. Treatment can include medication and physical therapy.

Spondylolisthesis is most common in the lower back and occurs more often in adolescents and adults.

This article explores types, symptoms, and causes of spondylolisthesis. It also discusses how doctors diagnose and treat the condition.

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Due to the varying degrees and causes of the misalignment, healthcare professionals classify spondylolisthesis 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 their developmental years. In both cases of type I spondylolisthesis, a child may not experience any symptoms or problems until later in life.

Type II

In type II, 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 to type VI

Type III is associated with aging and the natural wear and tear on a person’s body.

Type IV is a fracture that occurs anywhere in a vertebra except in the pars interarticularis region.

Type V is caused by certain diseases that can weaken the bone, such as the spread of cancer, tumors, or osteoporosis.

Type VI is an uncommon spondylolisthesis caused by weakening of the back due to surgery.

Grades

Healthcare professionals further classify spondylolisthesis into grades, according to how far out of place the vertebra is. The grades are:

  • Grade 1: 25% of the vertebral body has slipped forward. This is the lowest grade.
  • Grade 2: Between 25% to 50% of the vertebral body has slipped forward.
  • Grade 3: Between 50% to 75% of the vertebral body has slipped forward.
  • Grade 4: Between 75% to 100% 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 as a result. However, a person may develop symptoms as they age.

Symptoms can range in severity from nonexistent, to a loss of bowel and bladder control in more severe instances.

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 the 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 vertebral problem that a doctor may not identify until much later in life. Others experience an injury to the back, either repeatedly or on a single occasion.

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:

Many people are unaware that they have spondylolisthesis, as it often causes no symptoms. In these instances, 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 imaging scans of the back, which may include X-rays, MRI, or CT scans.

Visual examination of the imaging scans is often enough to determine if a person has spondylolisthesis, as well as to decide the grade.

Sometimes, a doctor may order additional imaging to determine the exact locations of the fractures, which helps guide the individual’s treatment.

A doctor may be able to identify the cause of spondylolisthesis based on the answers to the initial questions about when and how the symptoms began.

Treatment options include at-home care, therapies, and, in some cases, surgery.

A person can start treatment at home through a variety of methods, including using over-the-counter medication for pain relief.

If overuse has caused the spondylolisthesis, a person should stop any activities that aggravate the pain.

A doctor can prescribe additional pain relief and anti-inflammatory medications if necessary. They may also order physical therapy.

Physical therapy can 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 severe cases, a doctor might recommend surgery. For example, if there is spinal damage, the vertebra continues to slip, or the pain is extreme.

A surgeon can remove excessive bone or fuse the vertebrae back together. They will also advise a person on the appropriate steps to take after the procedure to aid in recovery.

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 condition.

For those who experience pain, numbness, or other symptoms, the overall outlook is positive. Most people can manage their spondylolisthesis with a combination of therapies and medication.

However, sometimes, a person may need to consider surgical options. After surgery, the individual can expect a recovery period lasting several weeks to months before returning to their usual activities.