Brachialgia is the medical term for pain produced by a trapped nerve in the neck leading to pain radiating down the arm. Like sciatica, it can be of sudden onset and extremely severe or of gradual onset and with symptoms that are more prolonged. The cause of the trapped nerve in the neck that produces the brachialgia is either a disc prolapse or more longstanding degenerative changes producing compression on a nerve root.
What other symptoms can accompany it?
Because the cause of the brachialgia is a trapped nerve, there are other symptoms that can be associated with the arm pain. Most typically, these symptoms are of pins and needles (paraesthesia) in the arm and these symptoms may be very localised, for example exclusively into the thumb. The distribution of both the pain and the paraesthesia does depend on which of the nerve roots are compressed.
The other common sensory disturbance that a patient with brachialgia describes is numbness in the arm. Again, this does not tend to be global but rather in a specific distribution that is related to which of the cervical nerve roots is compressed.
Rarely, the severity of the nerve root entrapment in the cervical spine is so marked that in addition to producing pain and/or sensory disturbance, the motor (power) function of the arm is affected. This is rare but in such cases the sufferer may notice reduced power in the arm. As with the sensory disturbances described above, this is commonly very localised. For example, the sufferer may notice weakness of their triceps muscle such that they are unable to extend their elbow, an action required when pushing things away or doing such physical activities as press-ups.
What is the treatment for brachialgia?
A large proportion of people with brachialgia due to a disc prolapse will get better in time without requiring surgery. The disc prolapse gradually resolves thereby relieving the nerve compression and resulting in a reduction in pain. This process can take some weeks, but for the majority of sufferers, their sciatica has significantly improved within 2 months of initial onset. As a result, the early treatment of brachialgia focuses on pain management, for which a variety of techniques are used including medication and epidural steroid injections.
Surgery will be considered for brachialgia in the following situations:
- If the pain fails to subside within a few weeks of onset
- If the pain is not controlled with medication/steroid epidural injection
- If there is associated muscle weakness
- If there is a threat spinal cord function
When brachialgia is caused by a disc prolapse (rupture, herniation, bulge) pressing on the nerve root, the purpose of surgery is to remove the lump of disc pressing on the nerve and thereby relieve the symptoms. The other cause for brachialgia is nerve entrapment due to more widespread degenerate changes than a simple disc prolapse. These degenerate changes (cervical spondylosis) cause thickening of the bone edges next to the disc (osteophytes) and thickening of the facet joint and ligamentum flavum. Whatever the cause, the purpose of the surgery is to ensure that the nerve root is adequately decompressed by removing the tissue compressing the nerve and thereby relieve the pre-operative symptoms.
What does the surgery for brachialgia entail?
Two operations can be employed to decompress a trapped nerve in the neck, ngteriro cervical discectomy with fusion or disc replacement and posterior cervical foraminotomy
The most common is an anterior cervical discectomy. This involves, under general anaesthetic, a horizontal incision in the front of the neck after which the surgeon approaches the front of the cervical vertebra. Although passing some important structures such as the carotid artery, jugular vein, oesophagus and trachea, the approach is relatively simple and follows natural tissue planes without needing to damage muscles. Once arriving at the front of the cervical vertebra, the surgeon ensures the correct level with an intra-operative x-ray. With an anterior cervical discectomy, almost the entire disc is removed allowing the surgeon to pass through to the back of the vertebra where the nerve root lies. In the case of brachialgia due to a disc prolapse, the lump of disc which has herniated out can be removed. In the case of osteophytic thickening, these bone spurs are drilled away, again with the same object of decompressing the nerve root.
At the end of the procedure there is, therefore, a space between the two vertebrae where the disc has been removed. A fusion device called a cage can be inserted into this space which is effectively a hollow box made of carbon fibre or PEEK Polymer into which some bone or tricalcium phosphate bone-graft substitute is packed.
An alternative to fusion is a disc replacement. The operation is exactly as described above but the implant is mobile and can move like a disc. There is some evidence that a disc replacement can improve neck pain and results in less strain on adjacent discs over time. Only a minority of cervical disc operations are appropriate for disc replacement and your neurosurgeon can discuss this option with you
Post-operatively, the patient can mobilise on the day of surgery and is generally home within 2 days of the surgery. Despite being a relatively minimally invasive procedure, it remains a serious neurosurgical operation and we would recommend 6 weeks off work, although the recovery period would be the subject of discussion between you and your surgeon.
The other less frequently employed operation to decompress the nerve root is a posterior cervical foraminotomy. Rather than approaching the cervical spine from the front of the neck, this approach is made through a midline incision in the back of the neck. The muscles are stripped off the relevant part of the cervical spine. The precise position of the incision is determined by an intra-operative x-ray. Once the spine has been reached a fine drill is used to remove part of the bone overlying the canal through which the nerve root leaves (foraminotomy). Also removed at the time of this operation is the area of ligamentum flavum that is often thickened and contributing to the compression of the nerve root. This operation can be done as a primary procedure for a nerve root entrapment, or is sometimes used as a second operation to augment the anterior decompression. This dual approach is relatively infrequently required.