Degenerative Spondylolisthesis - Symptoms, Diagnostics & Therapeutic Approaches

Introduction

The term spondylolisthesis means a slipped vertebra, where one bone in the spine slips forward over another. Degenerative spondylolisthesis is a form of spondylolisthesis that occurs with the aging process. It is characterized by the forward slippage of one vertebra over the one below it. Usually, it appears in the lower back. The most common spots are the lumbar spine, including L4-L5, L3-L4, and L5-S1.

Degenerative spondylolisthesis (DS) is frequently observed in individuals aged 40 and above, in contrast to the other types typically present in adolescents. In DS, the slip is usually small, about 14 percent. But because the spine's protective arch remains intact, even a slight slip can press on important nerves.

What Causes Degenerative Spondylolisthesis?

1. Aging: Degenerative spondylolisthesis happens because of changes related to aging in your spine.

Age-related changes that cause DS include

• Spinal Disc Degeneration - The discs between the spinal bones break down over time.

• Weakening Ligaments - The ligaments that keep the spine stable become less strong and flexible.

• Facet Joint Arthritis - The joints that link the spinal bones can develop arthritis, reducing support for the spine.

• Muscle Weakness - Weakened muscles may fail to stabilize the spine effectively.

2. Genetics: Some individuals may be genetically predisposed to degenerative spondylolisthesis due to structural abnormalities in the spine that make it more susceptible to slippage.

3. Trauma: In some cases, acute injuries to the spine can damage the stabilizing structures and lead to spondylolisthesis.

4. Less Common Causes: Pregnancy and sports activities can speed up age-related changes in the spine and may lead to degenerative spondylolisthesis.

What Are the Signs and Symptoms of Degenerative Spondylolisthesis?

• Lower Back Pain - This is the most common complaint from DS patients, and it can come and go over many years. Patients often notice that their symptoms change with different activities, like going from lying down to standing, and the pain can worsen as the day progresses.

• Leg Pain - This is another significant symptom, often radiating into the back of the thighs. This leg pain can switch from one leg to the other.

• Neurogenic Claudication- This causes patients to stop and sit after walking only a short distance. This is often the point when patients consider surgery. These symptoms are reported by a large percentage of patients seeking help from orthopedic specialists.

• Bladder and Bowel Control- DS can affect bladder and bowel control in severe cases, although it typically presents more subtly than the acute cauda equina syndrome.

• Restless Legs Syndrome - Extreme cases may lead to restless legs syndrome, which includes calf pain, restlessness, an irresistible urge to move the legs, and muscle twitching. This syndrome can be exacerbated by conditions like congestive heart failure, which affects the blood flow in the lumbar nerve root area.

• Neurological Symptoms - Other neurological symptoms like numbness and weakness may be present.

• Changes in Gait - Changes in how an individual walks or moves may be observed as the condition progresses.

How Is Degenerative Spondylolisthesis Classified?

Spondylolisthesis is graded based on the extent to which the vertebrae have slipped. The Meyerding classification system is commonly used.

• Grade I (0-25% slippage) - This is considered mild spondylolisthesis. There is minimal vertebral slippage.

• Grade II (26-50% slippage) - Moderate spondylolisthesis where the vertebrae have shifted more significantly.

• Grade III (51-75% slippage) - Severe spondylolisthesis with a substantial shift in the vertebrae.

• Grade IV (76-100% slippage) - The most severe form of spondylolisthesis with complete slippage.

How Is Degenerative Spondylolisthesis Diagnosed?

• Medical History - The healthcare provider will inquire about the patient's symptoms, medical history, and any risk factors that might contribute to spondylolisthesis, such as family history or previous injuries.

• Physical Examination - The doctor will conduct a thorough physical examination, assessing the patient's posture, gait, and neurological function. This examination helps to identify areas of tenderness, muscle weakness, and abnormal reflexes.

• Plain Radiographs - These basic X-rays are the starting point. They show the forward slip of one vertebra over another, often in the lower back. In DS, the neural arch remains intact, leading to misalignment of the spinous processes, which can be seen on X-rays. Other common findings include narrowing of the spinal disk space, vacuum sign, endplate hardening, bony growths around the disc (peri discal osteophytes), and facet joint changes.

• Additional Imaging - Further imaging may be necessary depending on the patient's symptoms and clinical findings. This includes advanced options like computed tomography (CT), myelography, contrast-enhanced CT, and magnetic resonance imaging (MRI). CT scans show facet joint alignment and degeneration. If a patient has symptoms consistent with spinal stenosis, MRI or post-myelographic CT may be needed to confirm nerve compression.

How Is Degenerative Spondylolisthesis Treated?

The treatment choice for degenerative spondylolisthesis depends on several factors, including the severity of symptoms and the patient's health.

Conservative Treatment

Many patients can manage their DS symptoms without surgery. This is particularly suitable for those who do not experience severe neurological issues. Conservative treatment includes:

• Rest for a day or two.

• Short-term use of anti-inflammatory medications if tolerated.

• Physical therapy, with exercises such as stationary bicycling, promotes spine flexion and alleviates pressure on the spinal cord.

• Weight management.

• Pain management may involve acetaminophen or other non-NSAID analgesics.

• Lumbosacral corsets may help with neurogenic claudication and spinal stability.

• Flexion exercises may be more effective in reducing pain and improving function for DS.

• Stabilization exercise programs targeting deep abdominal and lumbar multifidus muscles can reduce pain and disability.

• A combination of treatments, including exercises and medications, may be considered for DS with spinal stenosis.

• Chiropractic manipulation may provide short-term pain relief but lacks long-term evidence.

Epidural Steroid Injections

In cases where conservative treatments do not provide adequate relief, epidural steroid injections may be considered. These injections involve the delivery of corticosteroids around the affected nerve roots and spinal cord to alleviate pain and neurogenic claudication. While the long-term benefits of these injections for DS alone are not well established, some studies have shown short-term improvement, especially in cases of spinal stenosis.

Surgical Treatment

Surgery is typically reserved for DS patients with persistent or worsening symptoms and meets specific criteria.

These criteria include:

• Persistent or recurrent back and leg pain, along with neurogenic claudication or radiculopathies, despite non-operative treatment for three months.

• Progressive neurological deficits.

• Bladder or bowel symptoms.

The natural course of degenerative spondylolisthesis tends to be generally favorable, and only a small percentage of patients need surgery. Over time, the development of osteoarthritic spurs, ligament hypertrophy, and facet joint arthrosis can lead to secondary stabilization that prevents further slip progression.

Conclusion

While degenerative spondylolisthesis can be a source of pain and discomfort, it is manageable through various treatment options, both surgical and non-surgical. Many individuals can manage their condition without surgical intervention. Secondary stabilizing factors and the body's ability to adapt can contribute to stable or improved outcomes over time, especially for milder symptoms.