As we age the shock absorbing, fluid-filled central parts of our discs becomes dehydrated and more rigid. This entirely normal part of the ageing process results in discs that are less likely to prolapse.
Each disc lies between two vertebrae and is therefore a form of joint. As all joints wear and become arthritic they tend to bulge and become more ‘knobbly’. In the spine this results in the disc itself bulging, accompanied by bulges from the bone of the vertebrae lying either side of the disc. These bone bulges are called ‘osteophytes’, hence the name ‘osteodiscal’ bulge.
In constrast to disc prolapses, osteodiscal bulges enlarge slowly over years, are common in both the neck and lumbar spine and may press on both nerves and the spinal cord itself.
In contrast to neck and back pain, sciatica and brachalgia ‘radiate’ to different parts of the arm or leg, depending which nerve is compressed. This pain generally radiates beyond the elbow or knee, into the further parts of the limb. As the compression continues it may also cause numbness and weakness in the same area. These will also occur in a specific distribution. Asking patients about where their symptoms are felt and examining the pattern of sensation and power loss are important ways of confirming which nerve is being compressed.
Fortunately most head injuries are less severe than this. Nevertheless, it is important to be aware that even relatively minor head injuries can cause symptoms which may well last six months to a year. These include problems such as difficulty concentrating, nausea, vertigo and headache. These symptoms can be surprisingly disabling and there is no specific treatment other than time and rest. The good news is that they generally improve with time.
» Primary brain tumours
Nerve cells within the brain do not give rise to tumours, presumably because these neurones do not grow and divide after the first few months of life. Primary brain tumours are actually formed from the supporting ‘glial’ cells which surround, nourish and protect neurones. Broadly, glial cells are either astrocytes, which support and nourish neurones, or oligodendrocytes, which are responsible for electrical insulation of neurones. Primary brain tumours can be formed from either cell type and can also be a mix of the two cell types (astrocytomas, oligodendrocytomas or astro-oligodendrocytomas).
The World Health Organisation (WHO) categorises tumours into four grades depending on how rapidly growing they are. Grade 1 and 2 tumours are defined as being benign and grade 3 and 4 tumours are malignant. In practice, the distinction between benign and malignant tumours is different for brain tumours than it is for tumours elsewhere in the body. Unlike other tumours, brain tumours almost never spread to other parts of the body. Grade 1 tumours may remain static for many years and surgical excision is often curative. This may be true for grade 2 tumours, but they have a tendency to slowly progress and eventually ‘upstage’ to grade 3 and subsequently grade 4 tumours.
» Secondary brain tumours
Secondary tumours spread to the brain from other parts of the body. In treating these tumours the first step is to find out whether the tumour has also spread to other parts of the body. If there are only a one or two deposits, limited to the brain, then an operation to remove these may be beneficial. If there are widespread deposits it is not usually possible to remove them all and it is usually better to treat with chemotherapy and/or radiotherapy. If the original site of the tumour is not known then an operation to biopsy one of the tumours may be necessary. Operations may also occasionally be necessary to treat fluid build-up in the brain. Generally speaking however, patients with widespread ‘metastatic’ tumours are looked after by oncologists who have expertise in this field, rather than by neurosurgeons.
In practice the brain is often surprisingly tolerant of tumours and the first symptoms are often caused by a generalised rise in pressure within the skull (intracranial pressure) as the tumour grows. This results in headaches and nausea. Unlike other causes of headaches, these progressively worsen over weeks. It is said that headaches due to raised intracranial pressure are worse when doing activities that raise intracranial pressure a little in normal people. These include bending down, lying down and straining to lift objects. Unfortunately, most headaches are worse when bending or straining (if you don’t believe me, try picking up a heavy object next time you have a bad cold). One of the questions often asked to distinguish between the two is ‘is your headache so bad that it wakes you up in the morning, or do you wake up and then notice that you have a headache?’
Another way that patients first find out they have a headache is when they have an epileptic seizure. Single seizures are actually relatively common and 1 in 100 of us will have a seizure at some stage in our lives. Nevertheless, one of the investigations offered to patients after a seizure is a brain scan and a small percentage of these scans will show a tumour.
Finally, a proportion of patients may have brain tumours found during investigation of other diseases or during investigation of tumours elsewhere in the body.
To access some parts of the brain it is necessary to detach the muscles of chewing from the skull in the region of the temple. This muscle is re-attached afterwards but is often swollen for several days. Patients tend to find that this restricts their ability to open their mouth until the swelling eases. Fortunately this tends to be stiff but not actually painful. However, even with the best attempts to attach the muscle to its original position, the muscle is not generally as bulky as before. This means that patients and people who know them well may notice some asymmetry in the temporal region after operations in this area. This asymmetry is usually too subtle to be noticed by strangers.
Operations on the back of the neck tend to make the neck stiff and sore for at least 48 hours. This then wears off over a week or two and generally then goes away totally. Most of us will get some neck pain as we get older. It is rare but not unheard of for an operation on the neck or back to make the pain worse but this is unlikely.
In general, operations on the brain and spinal cord have a risk of roughly 1 in 100 of infection or bleeding into the wound or leakage cerebrospinal fluid after the operation. These are rarely life threatening complications. They may result in a longer stay in hospital and possibly further procedures to treat them, but usually result in a good recovery.
More rarely, there may be damage to either the brain or spinal cord, either during the operation or by a post-operative complication such as bleeding into the nervous system. This complication can result in catastrophic and permanent problems but is rare. Operations on certain areas of the brain may carry higher risks (in which case it can be an advantage to do the operation with the patient awake, so that brain function can be monitored). This is rarely necessary and will be discussed during the consultation in individual cases.
Certain other structures in the body can be at risk during the surgical approach. One example of this is that there is a risk of approximately 1 in 100 of having a permanent hoarse voice following anterior surgery in the neck. Surgical approaches have been developed to avoid other structures as much as possible and operations on the brain and posterior parts of the spine generally do not involve having to pass other organs.
The risks of any general anaesthetic include chest infections, blood clots in the legs and lungs, heart attacks, stroke and a very small chance of dying from the procedure. For a patient how is otherwise fit and well, these are low risks.
In practice patients are given a low dose of medication to control any pain and discomfort during the operation. This dose is adjusted so that the patient is awake during the main part of the operation. The initial ‘opening’ part of the operation is usually performed with the patient asleep. It is possible to put patients back to sleep during the ‘closure’ part of the operation but most patients find that this is not necessary.
Some patients feel the prospect of having an operation performed with them awake is not something they could countenance. Other patients find the idea of playing a major part in deciding how far their operation should progress gives them a sense of greater control and involvement in their operation. The surgical procedure performed during an awake operation is no different from asleep operations but awake operations do require real teamwork between the surgical team, anaesthetic team, the therapist assessing the patient and the patient themselves. We rarely need to perform operations with the patient awake but if we do need to do so, we can discuss this when we meet.
Operations on the back are generally sore for the first few weeks (although often much less sore than the sciatica which lead to the operation being done). You will be given painkillers that cover the majority of the pain. Patients generally find that their pain is controlled if they rest.
You should be nearly back to normal by 2 weeks but may feel sore and tired when trying to do more strenuous activities, including driving. It usually takes about six weeks to be back to fully normal but this varies from person to person and with different operations.
After a spinal operation you are generally fine to drive when you feel safe to do so. I advise patients to sit in a car and check that they can work all of the controls, use the mirrors and look over both shoulders quickly and without discomfort. Once this stage is reached (generally around six weeks after an operation) you are safe to drive. However, some insurers have different rules, sometimes including a clause saying that you are not covered until you have been seen in outpatients after your operation. Do check your insurance policy.
Spinal conditions are generally similar but occupations that involve repeated heavy lifting will increase the chance of wear in the joints of the back. Through mechanisms thought to involve damage to the smallest blood vessels, smoking also seems to increase the rate of wear in the discs in the back but many people will smoke for years with no back problems and other people will have significant problems with their back despite never having smoked at all.