WHAT IS CERVICAL SPINAL STENOSIS?
Cervical spinal stenosis is a broad term which refers to a range of symptoms which can result from the narrowing of the spinal canal in the neck. This may be due to age, injury, or degeneration.
The spinal canal is a long tunnel that runs down the centre of the spine. This canal sits directly behind the bony blocks, or veterbrae which form the spine. It contains the spinal cord and nerve roots. When the spinal canal is narrowed, the spinal cord and nerve roots may be compressed. This is known as cervical canal stenosis.
The spinal nerves (‘nerve roots’) leave the cervical spinal canal by passing through the intervertebral foraminae. The nerves then travel to the arms where they control sensation and movement. When the intervertebral foraminae are narrowed, the nerve roots may be compressed. This is known as cervical foraminal stenosis.
In summary, cervical canal and foraminal stenosis are both caused by the same underlying processes, and can present in a similar fashion. The two conditions often co-exist and can be broadly referred to as cervical spinal stenosis.
What causes cervical spinal stenosis?
Cervical spinal stenosis can be the gradual result of aging and "wear and tear" on the spine. It can also occur as result of a genetic predisposition. It may also be the result of an intervertebral disc prolapse.
As a person ages, or as a consequence of excessive “wear and tear”, a number of processes occur:
- The intervertebral disc loses much of its water content (“dehydration’ or ‘desiccation’). As a result, the discs decrease in height and bulge backwards toward the spinal canal and intervertebral foramen.
- The facet joints (the small joints of the spine which hold the vertebral bodies together) and ligaments also thicken and harden to further narrow the spinal canal and intervertebral foramen.
- Bone spurs (osteophytes) often form, compressing nerves or the spinal cord.
- Spondylolisthesis, the slipping forwards of one spinal bone (‘vertebra’) on another, also may occur and lead to compression.
The end result of all of this additional tissue formation is that the softest structures in the spine get squashed. Unfortunately, these are the spinal cord and nerves.
Symptoms due to compression of the spinal cord and/or nerves include:
- Arm or hand pain
- Bowel or bladder incontinence
- Imbalance when walking
- Lack of coordination and “clumsiness”
- Neck pain
- Shoulder pain
- Weakness in the arms or legs
Stenosis in the cervical spine can affect both the:
- Spinal nerves causing arm pain (radiculopathy)
- Spinal cord resulting in imbalance and coordination difficulty (myelopathy)
If spinal nerves are being strongly pinched, a radiculopathy may occur and the patient can experience constant arm pain, as well as numbness and weakness. When the intervertebral foraminae (‘neuroforaminae’) are reduced in size due to surrounding build up of tissue, the nerves react to the pressure by swelling. This causes further pressure on and irritation of the nerves. Compression of the nerves is generally worse when the patient extends the neck (but is sometimes worse when the chin is placed forwards on the chest), and this usually increases the amount of arm pain.
Spinal cord compression may result in a myelopathy. This is an irreversible weakness and loss of muscle bulk of the muscles of the arms, hands and sometimes legs. Balance and coordination problems, as well as bowel and bladder incontinence may develop.
The symptoms of cervical spinal stenosis may be very mild or even absent even when significant stenosis is present. This is because the spinal cord has the capacity to accommodate to some extent. However, a sudden or severe force such as a car accident or fall can result in severe symptoms in a patient with pre-existing cervical stenosis. The medical term for one such syndrome is ‘central cord syndrome’.
To determine the cause of your symptoms, your neurosurgeon or spinal surgeon may require several radiological investigations. These typically include computed tomography (CT), and magnetic resonance imaging (MRI).
In some situations, such as when you are unable to have an MRI, you may also undergo a CT myelogram, where a CT scan is performed after contrast dye is injected into the spinal canal.
Shoulder problems may sometimes be confused with pain due to pressure on the nerve roots, and a shoulder ultrasound and/or MRI may be ordered, or an orthopaedic opinion obtained.
Cervical spinal stenosis is almost always treated conservatively in the first instance.
Medications to relieve pain and reduce inflammation are utilised. Pain relievers such as paracetamol and codeine may be used. Non-steroidal anti-inflammatory drugs (NSAIDS) such as aspirin, ibuprofen and naproxen may also be used to relieve pain as well as reduce inflammation and swelling. Other potential medications include a short course of corticosteroids (prednisolone, cortisone), as well as medications for nerve pain (such as pregabalin).
Other nonsurgical treatments for cervical spinal stenosis include physiotherapy, chiropractic, acupuncture and osteopathy. Physical therapy can also include the use of heat or ice packs, ultrasound, electrical stimulation, and massage. These treatments can relax tight muscles and ease pain or discomfort.
Nerve sheath injection
In more severe cases, local anaesthetic may be injected around the compressed nerve (transforaminal nerve sheath injection) and can have both diagnostic and therapeutic value.
Severe or unresponsive cases of spinal stenosis may require surgery. There are several types of surgery performed to relieve pressure on the spinal cord and nerves, and to help strengthen the spine. These include:
- Anterior cervical decompression and fusion
- Cervical arthroplasty (artificial disc insertion)
- Cervical laminectomy
- Keyhole foraminotomy
- Posterior cervical decompression and fusion