The cervical spine is the medical term for the bones, joints and soft tissue of the neck. The cervical spine has what is known as a central canal which houses the spinal cord running top to bottom from the head above. The moveable joints of the cervical spine include the intervertebral discs and interlocking facet joints at each level. The intervertebral disc space provides the height required for a gap on either side where nerves are able to exit the spinal canal. This space is known as the intervertebral foramen (foraminal space). Cervical nerve root entrapment is a condition in which as the nerve roots pass through this foramen they are compressed.
An initial diagnosis of nerve root entrapment can be reliably made from an experienced doctor or physiotherapist undertaking a history and examination.
Typical symptoms will normally be significant, diffuse arm pain in one or both sides. The onset may be gradual or come on suddenly. Oftentimes, cervical nerve root entrapment may also cause associated sensory symptoms such as pins and needles, tingling or numbness. There may be a feeling of weakness in the arm or hand but only in rare circumstances is strength significantly affected.
To confirm a possible nerve root entrapment during a clinical examination a doctor of physiotherapist will try to establish a relationship between possible neck position and the symptoms. Spurling’s test which involves extending and rotating the neck towards the painful side (thereby increasing any possible compression on the nerve root) is commonly used to see if it increases symptoms.
Each nerve root innervates a particular area of skin as well as muscle or muscle groups with power. As such, during an examination, where nerve root entrapment is suspected, deep tendon reflexes and power testing can be used to differentiate which level of the cervical spine may be at fault.
Once a clinical examination has been completed, to confirm the diagnosis an MRI scan is required. Unfortunately, MRI scans will often demonstrate changes related to age and this may include pressure on one or more nerve roots. Thus, cervical spine MRI scan results must be correlated carefully with the history and findings of the clinical examination.
The majority of nerve root entrapment is secondary to gradual, age related processes within the cervical spine. However, there will often be not one but several structural changes which will actually lead to the symptoms develop.
Unlike the lower spine (lumbar spine) where the intervertebral discs are large and hydrated, the discs in the cervical spine are more fibrous in nature. This means that it is unlikely there becomes a large prolapse of the central disc material to cause compression within the neural foramina. However, age related changes towards the edges of the disc and the thick ligaments around the cervical spine are common and manifest in ossification (bony tissue formation) in these structures. Often, these changes are referred to as a disc ossification complex. The facet joints also enlarge in size over time. Over time, these ossified structures will begin to compress the nerve roots in the foramina.
In rare circumstances there may be an instability in one of the levels of the cervical spine. A condition known as a spondylolisthesis which can result describes a slip of one vertebrae on another can occur after trauma or due to age related changes. This can distort the intervertebral foramen space and lead to nerve root entrapment.
In many cases, individuals who experience symptoms from nerve root entrapment will also have structurally slightly smaller central and foraminal nerve canals.
The treatment of cervical nerve root entrapment will be based around the severity of the patient symptoms and structural issues on an MRI scan.
For individuals who experience their primary onset of symptoms in the absence of any worrying neurological loss, doctors and physiotherapists normally recommend an initial period of non-surgical management. This involves ongoing physiotherapy to help to mobilise stiff segments of the spine and increase postural strength to the upper spine and neck. Ergonomic changes will be recommended to avoid periods where there is significant neck extension which may place more stress on the nerve roots.
During periods of acute pain or through the night time if sleep is being made difficult, in certain cases, doctors may recommend a course of medication known as anti-neuropathic medication. These forms of medication are able to target pain specific ally from the nerve root.
In cases which do not respond well to a well organised course of physiotherapy and appropriate analgesia, pain management consultants may in some cases recommend image guided steroid injections around the affected nerve root(s).
In cases of significant neurological symptoms especially if the neurological symptoms are likely to worsen then early surgical decompression may be suggested.