Spondylolisthesis – Slipped Vertebrae

Your spine consists of a series of vertebrae, with the lumbar spine forming the curvature in the lower back. This section contains five large vertebrae connected by bony arches known as the pars interarticularis, along with facet joints that help stabilize the vertebrae. The center of each vertebra contains an opening that forms the spinal canal, housing the spinal cord. The spinal cord is protected by this canal and sends out nerves that transmit information between the brain and the rest of the body.

Spondylolisthesis arises when a vertebra shifts out of alignment. Factors contributing to this condition include the degeneration of facet joints or fractures. Over time, the facet joints can weaken, leading to one vertebra slipping forward, a condition known as degenerative spondylolisthesis. In rare cases, a stress fracture in the pars of a vertebra may result in isthmic spondylolisthesis. Misalignment can exert pressure on nerves or reduce the size of the spinal canal, resulting in spinal stenosis.

The symptoms of spondylolisthesis can vary based on the degree of vertebral displacement and any potential nerve involvement. Most cases are asymptomatic, but some individuals may experience lower back pain and stiffness. Muscle spasms can cause the hamstring muscles at the back of the thighs to tighten, leading to discomfort and affecting posture, which may hinder walking.

If a vertebra has moved significantly or is compressing the spinal canal, it can affect the spinal nerves, causing symptoms like lower back pain, leg weakness, numbness, tingling, and altered reflexes. Symptoms may worsen with prolonged standing or walking, while bending forward or sitting may provide relief by increasing space in the spinal canal.

In severe cases, compression of the lower spinal nerves can lead to Cauda Equina Syndrome, characterized by loss of bowel and bladder control, in addition to back pain and lower limb weakness. This is a medical emergency requiring immediate attention.

Diagnosis of spondylolisthesis typically involves a thorough review of medical history and physical examination by a healthcare provider. Patients are encouraged to share their symptoms and perform specific movements to assess muscle strength, joint mobility, and spinal stability. X-rays can help visualize spinal alignment, and further imaging may be necessary to detect nerve root compression or spinal canal narrowing.

Spondylolisthesis is graded based on the extent of vertebral slippage:

• Grade 1: Less than 25% slippage
• Grade 2: 25-50% slippage
• Grade 3: 50-75% slippage
• Grade 4: More than 75% slippage

Most cases fall within Grade 1 or 2.

Asymptomatic spondylolisthesis usually requires no treatment. For those experiencing symptoms, management typically focuses on pain relief and restoring function. Nonsteroidal anti-inflammatory drugs (NSAIDs) can alleviate discomfort, and if these medications are insufficient, doctors may suggest epidural steroid injections to reduce inflammation and pain directly at the site.

Successful pain management may enable participation in physical therapy, where patients learn exercises to strengthen the back, abdomen, and legs, along with stretching techniques to maintain hamstring flexibility and improve posture.

Surgery may be indicated for individuals with Grade 2 spondylolisthesis or higher, particularly if the condition is unstable or causing significant neurological symptoms. Surgical options include spinal fusion to stabilize the vertebrae or lumbar laminectomy to enlarge the spinal canal and relieve pressure on the spinal cord or nerves.