What is Cervical Myelopathy?
Cervical myelopathy is a medical condition, where the spinal cord gets squeezed at the neck portion of the backbone. This pressure can lead to lasting muscle contractions known as spasticity, heightened reflex responses, abnormal reflexes, clumsiness in the fingers or hands, and difficulty in walking. Typically, it starts quite slowly and gets worse over time, leading to a gradual decrease in physical abilities.
Without appropriate medical intervention, individuals may run the risk of serious paralysis and loss of body functions. The usual treatment involves surgery to relieve the pressure in the affected area of the spine, which is commonly followed by fusion – a procedure that joins two or more bones in the spine. It is important to know that the chances of recovery can be lower if the symptoms last for over 18 months, if the neck’s mobility is reduced, and in females.
What Causes Cervical Myelopathy?
Myelopathy is a condition that happens when the spinal cord is compressed, while stenosis refers to the narrowing of a channel that is usually open. People who have a naturally smaller neck spinal canal are more likely to develop myelopathy. This condition can worsen over time due to a narrowing of the spinal canal or a herniated disk in the neck.
There are certain places in the neck, specifically in the areas of the fifth and sixth or the sixth and seventh vertebrae, where this condition is more likely, due to the higher level of movement allowed in these spots. Other causes of this canal narrowing can be the folding inward of a ligament in the spinal cord, a slipped disk, bone spurs, and the enlargement of small joints in the spine.
Patients with canal narrowing of more than 60% (meaning the space is less than 6mm) will almost always develop myelopathy. Age is a major factor in determining both the risk of complications during surgery and the likelihood of a less than favorable recovery in regards to nerve function.
Risk Factors and Frequency for Cervical Myelopathy
Interestingly, patients with neck pain and radiating symptoms that follow a certain nerve path, or dermatome, are more likely to see improvement from surgery than those without this type of pain. This is because this kind of pain is more likely to come from a specific source if it follows a specific muscle or nerve region, or myotome. In fact, surgery tends to help about 65% of people with neck pain and these radiating symptoms.
There is also a higher risk of a condition called cervical myelopathy among Asians. This condition is more prevalent among individuals aged 30 and older in this demographic group. The increased risk comes from a more common occurrence of bony growth along the spine’s ligament, a key cause of compression in this condition.
Signs and Symptoms of Cervical Myelopathy
Cervical myelopathy primarily results in symptoms affecting the arms. Patients may experience clumsiness in hand movements and struggle with intricate tasks like buttoning up a shirt, combing hair, holding tiny items, or distinguishing between coins. In some instances, signs in the legs can occur, including a wide-based walk and weakness. Neck pain, radiating pain along a nerve route, and a sensation akin to an electric shock when the neck is in certain positions, known as Lhermitte sign, are common complaints. Two severe symptoms implying a worse prediction are general weakness and disorders in bowel or bladder function.
When getting a patient’s health history, doctors will be keen on understanding the pain’s onset, the spread of the pain, and any triggering incidents. The presence of radiating pain usually suggests that the spinal canal is narrow. Surgical treatments tend to yield more predictable outcomes when radiating pain is the main issue rather than vague neck pain, which is typically due to strained and tired muscles.
Every check-up should involve testing the nerve functions of the arms, legs, bladder, and bowels. A careful examination requires being organized and patient. Not only should the doctor assess the strength but also the sensation and reflexes. It’s equally crucial to check the skin on the back, making note of any sensitivity to pressure or any past surgical scars.
Testing for Cervical Myelopathy
If a doctor suspects a patient has a condition called cervical myelopathy, they’ll perform a series of examinations and tests to confirm the diagnosis.
Firstly, they’ll study the patient’s walk, or gait, checking for any balance problems or stiffness.
Next, they’ll check the patient’s reflexes to detect any over-responsiveness. This might involve testing different areas like the biceps, a muscle in the upper arm, the brachioradialis, which is in the forearm, and areas in the leg such as the patellar (knee) and Achilles (lower back of your leg).
The doctor might also do the Lhermitte sign test, where they ask the patient to bend their neck forward. If this bending causes an electric shock-like feeling, it could indicate the presence of cervical myelopathy.
The Hoffman sign test is another common examination. The doctor will quickly extend and release one of the patient’s fingers. If the test is positive, the patient’s thumb or index finger will reflexively bend.
Other tests might include provoked wrist and finger reactions that extend to apparent odd places within the patient’s arm to examine nerve connectivity. And, the doctor may ask the patient to extend their hand; if any of the fingers held in extension drift into a flexed position, this could be a sign.
Lastly, they may do a grip test where they ask the patient to repeatedly make a tight fist.
In addition to these physical evaluations, the doctor may ask for imaging tests such as x-rays or an MRI scan.
X-rays are essential for examining the spine from different angles. If possible, the patient will be asked to bend forward and backward during the x-ray process; these different positions can help the doctor understand the stability of the spine’s ligaments.
The Torg ratio is an x-ray measurement which compares the cervical canal’s diameter (the canal inside the neck part of the spine) to the width of the spine in the neck area. A ratio lower than 0.8 may indicate an inherited narrowing of the spinal canal, called stenosis.
An MRI scan provides more detailed images, and is the best option to examine the spinal cord and the disc space (the cushion-like discs between the bones in the spine). The MRI findings could show stenosis, or a canal space of less than 10mm. The MRI is crucial for checking the spine for any other abnormalities, although it’s important to remember that some abnormalities can appear in these scans for patients without any symptoms.
Treatment Options for Cervical Myelopathy
If you’re experiencing ongoing symptoms from spinal canal compression, such as severe back pain or numbness in your limbs, different treatments can provide temporary relief. These treatments include medications to reduce the inflammation in the spine, physical therapy to improve strength and flexibility, ultrasound treatments to promote healing, and, occasionally, injections of corticosteroids, which are drugs that can ease inflammation and pain. However, while these approaches might help reduce the severity of your symptoms for a time, they won’t provide a permanent solution if your condition keeps getting worse.
In cases where the symptoms keep progressing, strongly considering surgery might be the best course of action. Surgical treatment aims to increase the space within your spinal canal, thereby reducing or even eliminating the pressure on your spinal cord. Nowadays, doctors often recommend having surgery earlier rather than waiting because doing so can improve your outcomes. The procedure can be performed either from the front (anterior) or the back (posterior) of your neck.
A posterior approach, or surgery performed from the back, is generally preferred when there is a curvature in your spine (a condition called lordosis) or when the issue affecting your spinal canal is at the back. One type of surgery from the back is a laminectomy, which involves removing a piece of bone from your spine. This type of surgery is particularly suited for those who have a larger than usual curve in their spine and no instability in their vertebrae, or the individual bones making up the spine. However, it’s important to know that surgeries performed from the back might have a slightly higher risk of infection compared to ones done from the front.
Anterior cervical discectomy and fusion (ACDF) is a surgical operation performed from the front. In this surgery, up to three discs — the cushions between your vertebrae — can be removed. It’s been reported that afterwards, a small percentage of patients (9% to 27%) might experience a temporary sore throat and difficulty swallowing, although these symptoms usually go away within three months. Also, around 3% of patients might develop recurrent laryngeal nerve palsy, a rare complication affecting the nerves that control your voice box.
What else can Cervical Myelopathy be?
There are various medical conditions that impact the nervous system, some of which include:
- Central cord syndrome
- Chiari malformation
- Guillain-Barre syndrome
- Multiple sclerosis
- Syrinx
What to expect with Cervical Myelopathy
An MRI scan can give doctors and patients an idea of the possible improvement they can expect. According to a comprehensive review of MRI results by Tetreault and colleagues in 2013, certain findings on the MRI can suggest a less favorable recovery:
When we see high-intensity changes on a part of the MRI known as T2 and low intensity on another part called T1, this usually means a slower recovery rate and poorer improvement of motor symptoms. Motor symptoms are related to movement and muscle function.
When the T2 signal intensity is much higher in non-compressed areas compared to compressed areas (specifically between cervical vertebra 7 and thoracic vertebra 1), this is linked with a less favorable recovery rate according to the JOA scale. The JOA scale is a measure used to assess the severity of symptoms in the spine.
If there’s more frequent high signal intensity on T2, it generally predicts a worse recovery. In other words, certain patterns on the MRI can give us clues about how well and how quickly a patient might recover.
