Stereotactic localisation is an intraoperative tool that the Neurosurgeon may use as part of the planning and implementation of intracranial surgery. Once a general anaesthetic has been administered, the head is fixed in a position to ensure that it cannot move. A computer system known as stereotaxy is then registered to the various points of anatomy of the face and sometimes dots that have been affixed to the scalp preoperatively. Once these points have been registered, a pre-operative image, which is usually an MRI, but can be a CT, is then matched to it. A GPS type system, specific to the patient has then been set up.
Pre-operatively and then in a sterile fashion intra-operatively, a probe can be moved over the anatomy of the scalp and then the internal anatomy to localise normal and abnormal structures. This helps with pre-operative mapping of the underlying concern, make decisions on where the incision ought to be, check to ensure a concern such as a tumour has been completely removed, check the anatomy when it has been grossly distorted by intracranial pathology and generally to add further precision to the significant anatomical knowledge of the Neurosurgeon performing the surgery. Your Neurosurgeon will never rely on a computer-based system for guidance, but it can, and often does significantly, augment the Neurosurgeon’s ability to perform the surgery in an efficient manner.
Whilst stereotaxy is not always needed for intracranial surgery, it has become a very common technology utilised and one that your Neurosurgeon at Neuron is likely to consider for any cranial operation.
Generally speaking, cranial trauma, or head trauma, is an entity that we as a community aim to try to prevent. This can be seen with helmets in various sporting endeavour, recreational pursuits and various safety apparatus in cars and other modes of transport. The reason for this is the significant impact on an individual and that individual’s family through cranial trauma of any sort. We generally describe cranial trauma within three broad categories of mild, moderate and severe. Singular mild cranial trauma often does not cause secondary symptoms. Unfortunately, multiple episodes of mild head trauma certainly can, and even a single episode of severe cranial trauma often leaves a patient with lifelong medical concerns relating to it.
The outcome of head trauma relates to the severity and the frequency that it has occurred. The outcome can be anything from no symptoms through to chronic headache, reduced cognitive capacity inclusive of short term memory, behavioural change, psychological and psychiatric disturbance, loss of independence/the requirement for full-time nursing care and a host of other concerns. Generally speaking, moderate to severe trauma is dealt with acutely through an emergency department at a major tertiary referral hospital with the appropriate ancillary supporting infrastructure of intensive care, high dependency Neurosurgical capacity and rehabilitation, both slow and fast streams. There is usually the requirement for neuropsychological and occupational therapy assessments and treatments in reference to any degree of significant head injury.
Prevention really is better than cure in this concern, and with data provided by many areas of clinical medicine including Neurosurgery, governments around the world have legislated for safety procedures, devices and protective helmet’s in a range of activities such that this can be avoided if at all possible.
There are some cranial concerns that can arise even after what seems like a mild to moderate concern. These secondary symptoms can even occur some distance down the track from the episode of head trauma and sometimes the patient and family will not immediately think the episode of head trauma is the cause until speaking with a Neurosurgeon.
Chronic subdural haematomas
Chronic subdural haematomas in the adult patient population are generally seen in the older age groups. We do over time have a fixed cranial vault size, but our brain can and often does decrease in size. This can be accelerated through various medical concerns including the chronic overuse of alcohol. This reduction in size of the brain relative to the cranial vault leads to an increase in the fluid area over the surface of the brain. There is also more movement able to occur within the cranium such that the blood vessels between the brain and the skull can come under tension. Thus, even a single episode of head trauma such as falling and hitting the head or turning quickly and hitting the head on a cupboard door can be sufficient to cause a small amount of bleeding.
That small amount of bleeding may not be noticed at first, but over time may be repeated even without further cranial trauma until there is a sizeable clot of blood between the brain and the skull. Generally, a patient will describe the onset of headaches and perhaps even weakness that causes medical assessment, imaging, and the diagnosis of the cause. Often, in retrospect, the family will suggest that the individual has not been quite themselves for a period of time, often months and that had been increasingly so leading up to the onset of obvious symptoms.
Having said that, chronic subdurals do not necessarily have to be treated surgically, though they often are. If the symptoms are mild, chronic blood clots around the brain can resolve on their own and may be watched with imaging and clinical review, though activities such as driving and operating machinery should be avoided. Should surgery be necessary, it can take several forms, but in essence the requirement is to remove the blood between the brain and the bone, relieving the pressure on the brain itself and, therefore, removing the symptoms.
Unfortunately, however, even with adequate and appropriate drainage there is the need for further clinical and radiological review because a percentage of patients who require subdural haematoma drainage re-accumulate the haematoma with or without further cranial trauma. Finally, it is exceptionally rare for an anti-coagulant medication taken for another reason to cause a subdural haematoma without trauma, though certainly if the trauma was to occur these medications make a haematoma more likely. These medications must be stopped around the time of surgery and then the treating Neurosurgeon and prescribing doctor will work together to determine when or if the medication should be restarted post-operatively.
Brain tumours are an abnormal growth of cells within the brain. The cause of brain cancer is not fully understood. There are few obvious risk factors associated with brain tumours.
Brain cancers are usually named after the type of cell that they grow from, for example, gliomas arise from the glial cells, meningiomas arise from the meninges. Brain tumours range from low-grade and relatively treatable to high-grade, very serious tumours with poor outcomes.
Brain tumours are classified as either primary or secondary as well as benign or malignant. Primary brain cancers originate from the tissue of the brain or from structures near to the brain. Secondary brain cancers originate elsewhere in the body and then travel to the brain. Benign brain tumours usually consist of slow growing cells and will rarely spread elsewhere. Malignant brain tumours can be life threatening and are usually fast growing and aggressive.
Brain tumours are usually diagnosed through the use of CT or MRI scanning along with an extensive patient history and examination. A biopsy is usually the only true way of diagnosing these conditions.
Symptoms of brain tumours can be fairly general, with specific symptoms largely dependent on the location of the tumour within the brain. Symptom onset can become gradually worse over time or can happen suddenly, for example, a seizure may occur when the patient has otherwise been well.
Common symptomology may include:
- Problems with speech
- Problems with balance and dizziness
- Nausea and or vomiting
- Problems with thinking (confusion)
- Problems with vision (double vision or blurred vision)
- Changes in mood
- Weakness in a part of the body.
- Difficulty hearing
Treatment of brain cancers will largely depend on the type of tumour and its location within the brain. Usually surgery and a combination of radiation and/or chemotherapy are required.
Trigeminal neuralgia is the most common type of craniofacial pain syndrome. It affects women more commonly then men; symptom onset can occur from early adulthood. The condition is sometimes referred to as ‘tic douloureux’ due to the muscle spasms that typically accompany the pain. Trigeminal neuralgia is a neuropathic disorder involving irritation of the trigeminal nerve (The 5th Cranial Nerve or CNV/CN5). The trigeminal nerve is responsible for sensation in the face, eyes and teeth and also controls some of the motor function of biting and chewing.
Trigeminal neuralgia is usually characterised by intense facial pain lasting from seconds to several minutes or sometimes hours. The pain is intense and sometimes described as ‘stabbing’ or ‘electric shock-like’ pain; it can be debilitating in nature. The pain usually affects only one side of the face and most patients experience relief from the pain when they are asleep.
It can be difficult to determine the exact cause of trigeminal neuralgia; compression of the trigeminal nerve root, which can itself be caused by a blood vessel or tumour, should be considered and ruled out when determining the cause. Multiple sclerosis is a rare cause. Diagnosis is made with patient history and a description of the symptoms by the patient; MRI and blood tests can also be used to confirm the diagnosis. Without clear physical or laboratory diagnosis, the exact cause of trigeminal neuralgia cannot always be discovered
Treatment of this pain syndrome can be multifaceted and involve a combination of pharmacological and/or surgical intervention and will sometimes encompass the expertise of a pain physician. Surgical intervention may be involved though is not limited to, micro vascular decompression (MVD) or radiofrequency ablation (RFA).
MVD is performed to relieve the symptoms caused by trigeminal neuralgia. MVD is a surgical procedure that involves opening the skull (craniotomy) and exposing the trigeminal nerve at the base of the brainstem to insert a tiny sponge between the compressing blood vessel and the nerve. The operation usually takes around 90 minutes.
RFA is a non-invasive, short stay procedure used to treat various types of pain. RFA involves the use of radio-waves that produce an electrical current that will heat up a specific part of the nerve tissue and stop the pain signals that generate from that area, therefore ablating the nerve. To optimize the success of RFA the correct pain generators (parts of nerves) must first be identified. RFA can be a very successful procedure, but as the nerves will regenerate over time the procedure may need to be repeated. The lasting effects of RFA will vary with each patient; the pain relief achieved can range between 6-24 months.
Despite the use of antiepileptic medications, not all people are able to obtain control of their seizures. Whilst there are other treatment options available, one of the considerations may be surgery. The overarching goal of any surgical intervention for epilepsy is to reduce or stop the seizure activity while maintaining optimal neurological function.
Evaluation is always in the form of a multidisciplinary team for any type of epilepsy related surgical intervention and is generally extensive. A large number of tests must be undertaken to determine where the seizures originate from and whether surgical intervention would then be appropriate. Some of these tests will involve: MRI or fMRI, video/telemetry EEG, SPECT or PET scanning and neuropsychological evaluation. Your surgeon will discuss these tests and the reasons for requiring them at length with you.
Surgical intervention to treat epilepsy is considered for many different reasons and will vary for each person; this is something that your surgeon will discuss with you. Epilepsy surgery is usually done as either a curative measure or to improve quality of life through seizure reduction, usually the latter. Your surgeon will discuss the operative options available with the associated risks and benefits.
Many people experience a good clinical outcome from epilepsy surgery, that being either a total cessation of seizures or a significant decrease in them. Being seizure free can bring on significant changes in your life. Though this is a positive outcome, some people experience difficulties in adapting to these changes and can at times feel overwhelmed. This is a completely normal response and if this occurs you are encouraged to seek support. Psychologists and psychiatrists are extremely valuable in the pre- and post-operative setting.
Surgical treatment for epilepsy will encompass a multidisciplinary team approach with your treatment not only involving your surgeon but also a psychiatrist (routine consultation to assist in the management of what can be a difficult and stressful time) and neuropsychologist (routine pre and post-operative testing that help determine the areas of the brain that are related to and/or affected by seizures and their potential impact on the patients memory and thinking skills).
The area of the head that separates the brain above from the other facial structures (eyes, mouth, nose and hearing) and neck below is known as the skull base. Disorders of the skull base can be caused by infections, birth defects and head trauma; however, tumours are the most common disorder. Disorders in the skull base area can affect function of the brain or its complex senses (hearing, vision, balance).
Skull base tumours can be invasive and treatment can be challenging due to the complex anatomy of the skull base. Tumours arising in this area are difficult to access with surgery because of their location under the brain. Tumours of the skull base are often ‘primary’ tumours, in that they originate from within the brain or its’ surroundings and rarely spread to other parts of the body. These tumours are usually also ‘benign’, which means they are slow growing, but still life threatening due to their location in relation to the brain and its critical structures. As skull base tumours grow they cause an increased pressure within the skull cavity and therefore on the brain, thus causing the brain to become damaged or swell (oedema) or fluid to build up (hydrocephalus), which can result in permanent brain damage or death.
Common types of skull base tumours include:
- Pituitary tumour
Symptoms of skull base tumours will depend on the type, size and location of the tumour. General neurological symptoms can include headaches, vomiting, drowsiness, balance and coordination problems, vision loss or change, seizures, hearing loss, speech problems, changes in personality, difficulty swallowing and ringing in the ears (tinnitus).
Diagnosis of skull base tumours will include extensive history taking, neurological examination and radiological testing.
Given the invasive nature of skull base tumours, treatment will often involve a combination of therapies, which may include – observation, medications, surgery, shunting (to treat hydrocephalus), radiation and/or chemotherapy and embolization.
A pituitary tumour is a mass of abnormal cells that arise from the pituitary gland. The pituitary gland, a pea sized structure, is located at the base of the brain, just behind the nose. The pituitary gland is the ‘master gland’ of the body and it controls the secretion and levels of hormones within the blood stream, keeping them in check; it in turn is controlled by the hypothalamus (a pearl sized organ that controls a multitude of vital bodily functions).
Some pituitary tumours are hormone secreting and some are not, i.e.: some of these types of tumours cause the secretion of a certain type of hormone outside of the function of the pituitary gland and some of them do not. Pituitary tumours are usually ‘primary’ (originating from within the pituitary), slow growing and often ‘benign’ (non spreading). The main types of pituitary tumours are adenomas (non-cancerous).
Pituitary tumours are skull base tumours and can exhibit the same symptoms as discussed above, however, as the pituitary gland also controls the secretion of hormones, other symptoms are also often seen when a tumour is present, but will depend largely on which type of pituitary tumour it is. If the tumour is secreting a hormone, then high levels of that hormone will be present in the blood stream. If the tumour is non-secreting but affecting the function of the pituitary gland then there may be a deficiency in one or more hormone levels. A tumour of the pituitary gland may also result in growth of the gland and therefore an increase in its size, this is known as ‘mass effect’ and may also produce symptoms due to an increase in pressure on the surrounding structures in the brain. Signs and symptoms of this may include – persistent headaches, nausea and vomiting, change in vision (loss of peripheral vision and sometimes double vision), changes to appearance (round ‘moon-like’ face, changes in height, weight gain), difficulty with thinking (cognitive changes), fatigue, light-headedness, loss of sex drive (libido), erectile dysfunction (in men) and changes in menstrual cycle (for women).
The pituitary gland controls many different hormones, some of these include:
- Thyroid Stimulating Hormone (TSH) – targets the thyroid: stimulates secretion of thyroid hormones.
- Growth Hormone (GH) – targets all cells in the body: promotes a persons’ growth (indirectly), control of protein, lipid and carbohydrate metabolism
- Adrenocorticotropic Hormone (ACTH) – targets the adrenals: stimulates the adrenal gland to produce cortisol, this is essential for life and also helps to regulate blood pressure and blood sugar levels
- Antidiuretic Hormone (ADH) – targets the kidneys: helps the kidneys maintain the correct amount of water in the body
- Follicle Stimulating Hormone (FSH) and Luteinising Hormone (LH) – targets the ovaries in women and the testes in men: regulates the menstrual cycle in women and sperm production in men and sex hormone levels in both.
- Prolactin (PRL) – targets the breasts: is secreted in large amounts after childbirth to prompt milk production, but is present in both men and women.
Diagnosis of pituitary tumours will be similar to that of skull base tumours discussed above – history, examination, blood tests and radiologic imaging.
Treatment of pituitary tumours will very much depend on the type of tumour present, but is likely to involve medications, surgery and radiation therapy. However, in some cases, it may be appropriate to simply monitor these tumours with imaging over time. An endocrinologist (hormone specialist) will also be involved in treatment of pituitary tumours.
Hydrocephalus is caused by a build-up of fluid (cerebrospinal fluid or CSF) inside the cavities of the skull that leads to compression of the brain. It is often referred to as ‘water on the brain’. In normal circumstances, the body maintains equilibrium within the brain by constantly ensuring there are equal pressures of brain, blood and CSF (auto regulation); if there is inadequate flow of CSF a change of pressure occurs and therefore the pressure within the head increases, this can be a life-threatening problem and can in some cases cause permanent brain damage.
CSF is a clear, colourless fluid that circulates between the brain and spine. In essence, the brain floats in it and it acts as a protective lubricant for the brain and spinal cord. CSF is made mainly in the ventricles of the brain (by the choroid plexus) it then flows down channels through the brain and exits near the base of the skull; the body produces around 500ml per day of CSF; it constantly recirculates. The brain and spine are able to hold approximately 150ml of CSF at any one time; the fluid is drained primarily into the bloodstream.
If movement and drainage of CSF is hindered in any way, it will cause a build-up of fluid behind the blockage. This in turn causes the ventricles (cavities) within the brain to enlarge and fill with CSF and therefore the pressure within the skull increases and brain compression occurs.
CSF drainage can be hampered if:
- Flow of CSF is blocked
- It is not absorbed properly into the bloodstream
- Too much is produced by the brain.
Any build-up of CSF is called hydrocephalus. There can be many causes of hydrocephalus, but they can be summarised into the main categories as follows:
- Congenital – present from birth, usually associated with other birth defects (e.g. spina bifida)
- Acquired – occurs when there is infection or a tumour present and this leads to blockage of the CSF flow
- Normal Pressure Hydrocephalus – this mainly affects older people, occurs when there is an abnormal increase of CSF in the cavities of the brain, the cause of which is sometimes unknown.
Hydrocephalus can occur without causing any signs or symptoms within a person (asymptomatic). The strength of symptoms seen in hydrocephalus depends on age, amount of damage to the brain and the cause of the CSF blockage.
When symptoms are seen in young to middle-aged adults or older adults they may include:
- Difficulty in staying awake or waking up
- Balance problems or coordination changes
- Visual changes
- Difficulty walking
- Loss of bladder control or increased need to pass urine
- Problems with concentration and problems with thinking and decision making skills.
The signs and symptoms displayed in children and infants may vary greatly to what has been described above. Information regarding infants and children with hydrocephalus should be sourced elsewhere, as Neuron is an adult Neurosurgical practice.
Treatment for hydrocephalus will depend on the cause of the CSF blockage.
Treatment options may include a combination of:
- Drugs – medications to alleviate the cause and/or reduce the effects of hydrocephalus may sometimes be of value
- Observation – if the hydrocephalus is incidentally discovered (found during an investigation for something else) and the patient is asymptomatic, no specific treatment outside of careful management and review may be necessary
- Surgery – if the hydrocephalus is considered to be temporary (in case of bleeding) then a short-term drain can be placed (lumbar drain or external ventricular drain) until the underlying cause resolves. If there is a known cause of blockage (tumour) surgery can be performed to remove it. If the cause of the blockage is unknown or known and unresponsive to other treatment then surgery can be performed to re-route the flow of CSF. This is done by placing a very small flexible tube in the brain and diverting the flow of CSF into another part of the body (for example the belly) so it can be reabsorbed there; this is called a ventriculoperitoneal shunt.
A cranioplasty is an operation that is performed to repair a defect or deformity in the bones of the skull. Defects or deformities in the skull bone primarily occur when a part of the skull is removed during surgery for a removal of a tumour or for a repair following head trauma when a defect can’t be replaced at that time. The skull provides protection to the brain and its critical structures; a cranioplasty is performed to restore this protective barrier and to also improve the appearance of the skull contour.
Vascular anomalies refer to abnormalities occurring within arteries or veins. These anomalies can present in many different forms in both adults and children, but in the Neurosurgery they most often present as aneurysms or arteriovenous malformations (AVM).
An aneurysm is an abnormal swelling or bulge in a blood vessel wall. Aneurysms can occur anywhere in the circulatory system of the body, but are primarily found on the large artery known as the aorta and in the blood vessels of the brain. Aneurysms in the brain are caused by very different mechanisms than aneurysms that occur elsewhere in the body. When they occur in the brain they are known as cerebral or berry aneurysms.
Aneurysms occur due to a weakness in the wall of the blood vessel. Over time, as the blood pumps around this weakness it will cause it to ‘bulge out’. A cerebral aneurysm usually occurs where the blood vessel ‘branches’, as the blood vessel is more vulnerable at this point. Aneurysms can be present from birth (congenital) or can develop over time. The latter is more common.
Cerebral aneurysms are often not discovered until they become very large (very uncommon), leak or rupture, though increasingly, asymptomatic aneurysms are being found incidentally when a head scan is done for another reason. The type of symptoms produced will depend on the type and location of the aneurysm and if it is leaking or has ruptured. If the aneurysm is intermittently leaking, patients will often describe it as ‘the worst headache’ they have ever had. A ruptured aneurysm is a life threatening condition; death can occur within minutes, and most often there are no warning signs before a rupture.
Other symptoms may include:
- Severe headache with a rapid onset
- Neck pain or stiffness
- Increasing drowsiness
- Difficulty speaking
- Difficulty seeing (blurred visions or double vision) and/or sensitivity to light
- Nausea and or vomiting
It is not always possible to identify the cause of a cerebral aneurysm. However, some common causes may include:
- Hereditary (family history)
- Connective tissue disorders
In conjunction with a patient’s symptoms the diagnosis of a cerebral aneurysm will include a combination of a physical examination and radiological investigation (angiograms, CT, MRI, lumbar puncture).
Treatment depends on the size and location of the aneurysm. If the aneurysm is an incidental finding, is small in size (less than 3mm) and the patient is asymptomatic, a ‘watch and wait’ approach may be undertaken with the patient undergoing close observation. An asymptomatic cerebral aneurysm may still require treatment to prevent future rupture. Due to the delicate location of some types of cerebral aneurysms, it may be decided that it is too dangerous to risk surgical intervention. If treatment is appropriate, it will often be in a surgical form (clipping) or endovascular repair (coiling).
Clipping – a titanium clip is secured around the base of the aneurysm with the treatment goal being to isolate the aneurysm from the main blood vessel supply (‘starving it’) without blocking off any nearby arteries. Clipping of an aneurysm is performed under a general anaesthetic.
Coiling – in this procedure the aneurysm is accessed via an angiogram (through the blood stream) and microscopic titanium or platinum coils are inserted into the body of the aneurysm to stop normal blood flow from entering in to it, over time a blood clot will form inside the aneurysm and essentially prevent it from rupturing.
Your doctor will discuss the risks and benefits of these procedures in great detail. Outcomes of both procedures vary greatly; there is the potential for significant side effects in both procedures:
- Vasospasm – blood vessels spasm and then constrict, this can lead to brain tissue damage or death.
- Hydrocephalus – compression of the brain tissue due to increased pressure due to fluid not being absorbed on account of subarachnoid blood.
- Rupture of the aneurysm during the operation (prior to clipping or coiling) – causing a stroke or subarachnoid haemorrhage (bleeding in the brain)
- Permanent neurological and physical disability
Your doctor will carefully consider the risk-over-benefit of treating the aneurysm or observing it.
An AVM is an abnormal collection of blood vessels. AVM’s can be found elsewhere within the body (spine, kidneys), but are commonly seen in the brain (cerebral AVM).
An AVM arises when arteries connect directly to nearby veins without having the normal vessels (capillaries) between them. AVM’s are rare and are typically present from birth (congenital), though they can develop in adult life. In most people the cause of the AVM is unknown.
Cerebral AVM’s vary in size and location, they occur either on the surface of the brain or within it, but will be separate from the brain tissue. Most people will not know that they have an AVM; typically the onset of a persistent headache or a seizure will be the first symptom that is experienced. Sometimes, the first symptom experienced by a person with a cerebral AVM will be a stroke caused by bleeding in the brain due to a rupture of the AVM. A ruptured AVM is a life-threatening condition; it can result in permanent disability or death.
If the AVM has ruptured symptoms experienced may include:
- Sudden onset severe headache
- Drowsiness or loss of consciousness
- Visual disturbance – double vision, blurred vision
- Problems with balance and walking
- Seizures (caused by the AVM pressing on the brain and producing excessive electrical activity)
- Loss of feeling on one side of body (mainly seen in the face, arm and or leg)
- Problems with speaking or understanding someone else.
If the AVM has not ruptured, symptoms experienced may include:
- Persistent headaches, usually in the same one area of the head or the whole head
- Buzzing or noise heard in the ear (tinnitus)
Depending on the reason for the discovery of the AVM – incidental or due to onset of symptoms as described above – an AVM can be diagnosed through physical examination and radiological imaging (CT, MRI, MRA or cerebral angiogram, sometimes a combination of this testing is used). If the AVM discovery is incidental and you are asymptomatic, your doctor will discuss the risks versus benefits of observation over surgical intervention, in doing so, your doctor will need to determine the risk of rupture of the AVM and factors that may increase the risk of rupture, for example, pregnancy, age, size and features of the AVM.
If seizures are occurring as part of the AVM diagnosis, they will be best controlled through the use of anti-seizure drugs.
If surgical intervention is required, it can occur in a combination of forms:
- Endovascular embolisation – the cerebral AVM is accessed through the blood stream via the groin and a glue-like substance is injected in to the abnormal vessels, which stops the blood flow in to the AVM and reduces the risk of rupture.
- Stereotactic radiosurgery – if the cerebral AVM is located deep within the brain, it may be difficult to access and remove via surgery. If stereotactic radiosurgery is performed radiation therapy is delivered directly to the AVM, which causes it to scar and shrink, reducing the risk of rupture.
- Brain Surgery – this is an open procedure where the surgeon will remove a part of the skull to gain access to the AVM and then excise it. Taking away the risk of rupture.