The cervical spine, or neck, is composed of seven stacked bones called vertebrae. Spondylolisthesis is a spinal condition where one of these vertebrae slips forward over the bone directly beneath it. While this slippage most commonly occurs in the lower back, its presence in the neck—known as cervical spondylolisthesis—is less frequent. The condition can be more impactful in the neck due to the proximity of the spinal cord and nerve roots in this region. Understanding the mechanics of this displacement and its causes is the first step toward effective management.
Defining the Condition and Its Causes
Cervical spondylolisthesis is an anatomical instability characterized by the forward displacement of a cervical vertebra relative to the adjacent one below it. This misalignment is graded by the percentage of slippage, with higher grades indicating greater displacement. The condition is a mechanical problem resulting from the failure of stabilizing structures, which include the intervertebral discs and the small paired facet joints.
The most common cause is degenerative change, often occurring in people over 50. This degenerative form results from the gradual wear and tear of spinal components over time. As the discs lose height and the facet joints deteriorate, the spine loses its inherent stability, allowing one vertebra to slowly slide forward.
Less common categories include traumatic or isthmic spondylolisthesis, linked to a fracture in the pars interarticularis following a significant injury or trauma, such as a hyperextension accident. Rarer causes include congenital defects where the spine is malformed, or pathological changes due to tumors or advanced arthritis. Regardless of the underlying cause, the resulting instability can lead to pressure on surrounding neural structures.
Recognizing the Symptoms
The symptoms of cervical spondylolisthesis depend on whether the slippage causes mechanical instability or compresses nearby nerves or the spinal cord. The most frequent manifestation is axial neck pain, characterized by localized discomfort, stiffness, and a reduced range of motion. This pain is often chronic and dull, worsening with specific movements or after long periods in one position.
If the displaced vertebra narrows the space where a spinal nerve root exits, the patient may experience radiculopathy. This compression causes symptoms that radiate outward from the neck, typically into the shoulder, arm, or hand. These symptoms include:
- Tingling
- Numbness
- A burning sensation
- Noticeable weakness in the affected arm or grip strength
A more serious consequence is myelopathy, which occurs when the forward slippage causes direct compression of the spinal cord. Signs of myelopathy include difficulty with fine motor skills, such as buttoning a shirt or handling small objects, and changes in gait. Progressive weakness in the arms and legs or the development of bowel or bladder control issues are urgent signs requiring immediate medical attention.
Diagnostic Procedures
Confirming a diagnosis and determining its severity requires a physical examination and medical imaging. The initial assessment involves checking the patient’s reflexes, muscle strength, and sensation to identify signs of nerve root or spinal cord compression. The physician also evaluates the neck’s range of motion and pinpoints the location of axial pain.
Plain X-rays are the first imaging tool used to confirm vertebral slippage and measure its precise grade. To assess the degree of instability, doctors often order dynamic X-rays, taken while the patient bends their neck forward (flexion) and backward (extension). A significant change in slippage between these positions indicates spinal instability, which helps guide treatment decisions.
A Magnetic Resonance Imaging (MRI) scan is essential for visualizing soft tissues, including discs, nerve roots, and the spinal cord. The MRI provides detailed information on whether the slippage is causing nerve impingement or spinal cord compression, which X-rays cannot show. A Computed Tomography (CT) scan may also be used for a highly detailed view of the bone structure to identify fractures or bony growths called osteophytes.
Treatment Approaches
Treatment for cervical spondylolisthesis typically begins with conservative, non-operative methods, especially for low-grade slips without neurological symptoms. Physical therapy is a primary component of this approach, focusing on exercises to strengthen stabilizing muscles and improve posture to reduce mechanical stress on the spine. Modifying activities to avoid movements that aggravate the pain is also a simple, yet effective, initial strategy.
Medications are often prescribed to manage discomfort and inflammation, including nonsteroidal anti-inflammatory drugs (NSAIDs). For nerve-related pain, specific nerve pain medications may be used to calm irritated nerve roots. If localized pain persists, a physician may suggest an epidural steroid injection, which delivers a potent anti-inflammatory agent directly into the area surrounding the affected nerve roots.
When conservative treatments fail after several months, or if a patient presents with progressive neurological deficits or severe instability, surgical intervention becomes necessary. The primary goals of surgery are to decompress the neural structures, meaning removing the pressure from the spinal cord or nerve roots, and to stabilize the vertebral segment. Decompression involves removing bone or disc material that is impinging on the nerves.
Spinal fusion is the most common stabilization procedure. The surgeon connects the slipped vertebra to the one below it using bone grafts and hardware like plates and screws. This procedure eliminates movement between the two bones, preventing further slippage and stabilizing the neck. The choice of surgical technique, whether performed from the front or the back of the neck, is carefully tailored to the specific anatomical issue causing the compression and instability.