Spondylolisthesis | Types and Symptoms

Spondylolisthesis is a spinal condition where one of the vertebrae slips out of its normal position onto the bone below it. The slippage puts pressure on the nerves and can cause symptoms like back pain and numbness/tingling in the legs.

Anatomy and Function of the Spine

The spine is a complex structure made up of 33 vertebrae interlocked with cartilage discs and facet joints, held together by ligaments and muscles. This intricate design allows flexibility and support for the upper body.

The Vertebral Column

The 33 vertebrae are grouped into sections – 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 4 coccygeal. The lumbar vertebrae in the lower back bear the most weight and are common areas for spondylolisthesis.

Intervertebral Discs

Between vertebrae are discs made of cartilage with a gel-like core. These cushion vertebrae, prevent friction, and provide flexibility.

Facet Joints

Every vertebra has four facet joints linking it to neighboring vertebrae. These allow back motion and spinal stability.

Spinal Stability

Many components enable spine flexibility plus support body weight: vertebrae, facet joints, discs, ligaments and muscles. Imbalance stresses areas like lumbar vertebrae.

Spinal Cord and Nerves

The spinal cord runs through the vertebral foramen, carrying nerves linking the brain and body. Nerves exit at each vertebral level. Slippage can pinch nerves.

Types of Spondylolisthesis

There are five main types of spondylolisthesis, each with their own causes and characteristics:

Dysplastic Spondylolisthesis

This type occurs due to a congenital defect in the pars interarticularis region of the vertebrae, which are small bones that connect the facet joints. Since the spine does not form properly before birth, it is left vulnerable to slipping later in life. Dysplastic spondylolisthesis most commonly occurs between L5 and S1 vertebrae.

Isthmic Spondylolisthesis

Also called spondylolytic spondylolisthesis. This happens when there is a stress fracture in the pars interarticularis of the vertebrae, usually at L5-S1. This fracture weakens the bone and can lead to slippage. It’s common in young athletes who participate in sports with repetitive hyperextension and rotation.

Degenerative Spondylolisthesis

This is the most common type, happening in older adults due to aging/degenerative changes in the spine. As the disks between vertebrae wear down and facet cartilage erodes, the bones become more likely to slip forward. Degenerative spondylolisthesis happens most frequently between L4-L5.

Traumatic Spondylolisthesis

This rare type is caused by an acute injury leading to a fracture in part of the vertebrae, like the pedicle or facet joints. The fracture causes sudden instability and slippage.

Pathologic Spondylolisthesis

This happens due to an underlying disease weakening the spine, like osteoporosis, or from a tumor eroding the bone. Anything compromising vertebral integrity can produce slippage.

The location in spine, cause, and grade of slippage influences symptoms and ideal treatments for each type.

Causes and Risk Factors

There are several potential causes and risk factors for developing spondylolisthesis:

Sports Injuries and Overuse

Activities like gymnastics and football that hyperextend the spine can lead to stress fractures and eventual slippage. Growth spurts in adolescence can also be a contributing factor.

Genetics/Congenital Factors

Some people are just born with a higher risk. Thinner sections of vertebrae or general instability in the spine passed down genetically can predispose someone.

Aging and Degeneration

As spinal disks wear down from osteoarthritis and other age-related changes, the vertebrae become more likely to slip. Over 50% of cases occur in adults over 60.

Spinal Defects and Fractures

Defects like spondylolysis (crack in vertebra) or previous vertebral fractures place more stress on that area of spine and contribute to slippage.

Bone Disease/Spinal Tumors

Conditions like osteoporosis or spinal tumors can weaken vertebral bone and cause it to slip.

Those at highest risk: young athletes, individuals with family history, and adults over 50.

Symptoms

Possible symptoms include:

Back Pain

Most common complaint, typically worse with activity and better with rest. Can range from mild chronic pain to severe debilitating pain.

Leg Pain or Numbness

Slippage presses on spinal nerves, causing sciatica-like pain down the legs or numbness/tingling.

Muscle Tightness

Especially in the hamstrings and lower back as those muscles try to stabilize the spine.

Mobility Issues

Changes to normal spinal alignment impacts posture, gait and flexibility. Standing, walking and bending over can become difficult.

Bowel/Bladder Problems

Severe slippage compromises signals to/from bowel and bladder, causing incontinence in some cases.

Asymptomatic

Many spondylolisthesis cases cause no symptoms initially and are picked up incidentally on imaging for other reasons.

Diagnosis and Grading

To diagnose spondylolisthesis, providers use:

Physical Exam

Checking range of motion, areas of tenderness, muscle tightness, strength, reflexes and nerve function.

Imaging Studies

X-rays show slippage and alignment issues. CT scans and MRIs allow closer look at disks, nerves and soft tissues.

Severity Measurements

Slippage percentage determines grade from 1-4. Higher grades indicate greater instability and risk of symptoms/complications.

It’s crucial to distinguish spondylolisthesis from other conditions like slipped discs that can cause similar pain.

Treatment Options

Many treatment routes exist depending on grade of slippage and symptoms:

Lifestyle Changes

Sometimes rest, activity modification and posture correction does the trick.

Medications

Anti-inflammatories and muscle relaxants can alleviate pain and spasms.

Steroid Injections

Injections directly into spine temporarily reduce inflammation pressing on nerves.

Braces and Physical Therapy

Helps stabilize spine and build supporting muscle strength.

Decompression Surgery

Removes bone/disc material to create space for nerve roots.

Spinal Fusion Techniques

Several methods permanently join problematic vertebrae to prevent further slippage. Adding rods, screws or bone graft provides stability.

Outlook and Prevention

When needed, surgery boasts excellent outcomes. Still, it’s smart to take preventative measures:

Surgery Success

Most patients experience significant pain/symptom relief and can return to normal function after recovery period.

Preventing Recurrence

Regular strength training and checkups to catch progression early helps avoid repeat slippage.

Risk Reduction Tips

Minding posture, keeping active and fit, avoiding hyperextension activities can help lower odds of developing spondylolisthesis.

Conclusion

Spondylolisthesis has various causes but all involve some instability and slippage of the spinal vertebrae. While often asymptomatic initially, compression on the nerve roots can eventually trigger uncomfortable symptoms. Non-surgical care revolves around pain relief and muscle strengthening. For high-grade slippages causing marked symptoms, spinal fusion procedures usually eradicate pain and restore mobility quite well. Since aging degeneration is the most prevalent factor, everyone can benefit from building core/back strength and making spine-healthy lifestyle choices.