Spondylolithesis is the slip of a vertebra relative to another. This causes the spinal canal to narrow, squeezing on the nerves therefore causing back and leg pain or sometimes weakness.

Other symptoms include increased pain with exercise, leaning backwards, standing, and walking. Usually one will feel better if sitting or leaning forward. Also the person may notice tighten of the hamstrings. In severe cases the person may have reduced ability to control bowel or bladder functions (usually only in high grade cases).

Spondylolithesis is measured by grades. Grade I means 25% of vertebral body slipped forward, Grade II is 50% of the vertebral body slipped forward, Grade III: 75% of the vertebral body slipped forward, Grade IV: 100% of vertebral body slipped forward, and Grade V: Vertebral body completely fallen off. This is called Spondyloptosis.

There are two different types of Spondylolithesis. Degenerative spondylolisthesis is caused by wear and tear of the disc and facet joints over time. Lytic spondylolisthesis occurs when there is a break in the lamina causing the vertebra to slip forward.

A spondylolithesis can be a birth defect, but it can also be caused by trauma, normal wear and tear on the body, physical stress from sports like weight lifting, gymnastics, football, etc.

Treatments depend on the cause and the grade of spondylolisthesis. For non-acute low grade cases physical therapy for core strengthening and hamstring stretching is suggested. If the person does not do well with this, an epidural injection would be suggested. Acute lytic spondylolisthesis from trauma requires bracing until healed or surgery.

Surgery for spondylolisthesis involves three things:

  1. Stabilizing the spine by fusing it
  2. Correcting the alignment of the spine
  3. Decompressing the spinal cord and nerve roots

All three of these are accomplished by posterior lumbar decompression and instrumented fusion. A decompression involves removing the spinous process and part of the lamina of the spine to give it more room. It is referred to as “unroofing” the spinal cord. Correction of the alignment and stabilization is achieved by implantation of the screws and rods. Anterior surgery may be used to also help correct the alignment.