Brain, skull base and spinal cord tumours
Gliomas
Approximately 40% of brain tumours are gliomas. These originate from the glial cells, which support the neurons. The most common glioma is glioblastoma (approx. 50%), followed by astrocytoma (approx. 30%), oligodendroglioma (approx. 8%), and ependymoma (approx. 6%). Tumours are classified according to their biological behaviour: from WHO Grade 1 through 4. Apart from their space-occupying effect, Grade 1 and 2 tumours are benign and can usually be treated with a complete resection. Grade 3 tumours are fast-growing, and Grade 4 tumours malignant. The treatment of the latter ones is always a multidisciplinary challenge
Special techniques implemented at our centre
Modern surgery of gliomas always strives for complete tumour removal. The best possible resection demonstrably prolongs the overall and progression-free survival in the case of both low- and higher-grade tumours. However, the gain in survival time is into perspective if quality of life or independence are lost following the operation. The best-possible surgical result should be achieved while placing the least-possible amount of strain on the patient. Minimally invasive neurosurgery achieves this goal through the use of modern techniques in both the planning and execution of the procedure. The treatment plan is based on radiological imaging. Not only does this enable a presumptive diagnosis but also the assessment of the individual location of the tumour. Critical structures in relation to the tumour are detected, thereby determining the optimal access route with the least surgical trauma.
Neuronavigation helps the surgeon locate the tumour and thus increases the precision of the intervention. The location and extent of a tumour can be projected onto the surface of the head and, after craniotomy, to the exposed areas of the brain. With neuronavigation, the tumour boundaries are optimally defined, as the computerised device facilitates anatomic and surgical orientation – even in critical situations. The radicality can also be improved through the use of intra-operative MRI. During the operation, residual tumour tissue can be detected in the open skull and, if possible, completely removed.
Another big improvement is the fluorescence-guided resection of malignant tumours. Prior to surgery, the patient is administered an oral solution (Gliolan®). In the tumour cells, this solution is converted into a fluorescent dye, which becomes visible during the operation under special (fluorescent) lighting.
Electrophysiological monitoring is used to continuously monitor the integrity of the neurovascular structures – from the functional centres of the brain to the target organ in the periphery. Even in anaesthetised patients, the smallest impairments can be accurately assessed. The surgical procedure is then adjusted accordingly. If patients have suffered preoperative epileptic seizures and/or have displayed a pathological EEG (brain wave curve), intra-operative electrocardiography (ECOG) is performed. Potentially epileptic areas can be identified using electrode applied directly to the surface of the brain and then removed, if possible.
If cognitive functions or language (production and understanding) are jeopardised by the procedure, an operation in the awake state is advisable in order to be able to check and protect these brain functions.
These intra-operative techniques, which are routinely used in our centre, contribute to the safe and gentle removal of brain tumours while maintaining neurological function.
Meningiomas
Meningiomas are generally slow-growing benign tumours that originate in the meninges. They displace brain tissue and often grow to a considerable size before they start showing any clinical signs. Meningiomas account for 20–25% of all intra-cranial tumours. Each year, approx. 6 in 100,000 individuals are diagnosed with tumours. Women are twice as susceptible as men. Meningiomas at the surface can usually be operated on quite readily. Meningiomas of the skull base are somewhat more challenging because they displace cranial nerves and vessels and can lead to premature malfunctions. Approximately 5% of meningiomas are higher grade and fast growing. In these cases, radiation is often required after surgery.
Special techniques implemented at our centre
For tumours with an anatomically unfavourable location and strong circulation, catheter angiography and tumour embolisation are often performed before the operation. This facilitates the surgical work and minimises blood loss. The subsequent procedure is meticulously planned using preoperative imaging. The access route is determined based on the individual situation. The optimal skull opening in the operating room is controlled using neuronavigation. The goal is a small, minimally invasive access, which nevertheless allows for surgical reliability and radicality.
The endoscopic-assisted micro-surgical technique has proven successful when operating on meningiomas. Through the use of endoscopes, it is possible to see behind nerves and vessels. The extent of the access-related injury is reduced because important structures need not be displaced. Extensive and debilitating skull openings can be avoided by using such minimally invasive keyhole incisions.
Depending on its location and size, we often control the resection of a meningioma using intra-operative CT. Residual tumour components can thus be identified and surgical complications can still be ruled out before the closure of the wound.
In most cases, intra-operative monitoring is performed in order be able to control the functions of the cerebral cortex, the brain stem, and the cranial nerves in the anaesthetised state. These minimally-invasive surgical techniques, which are routinely used in our centre, contribute to the safe and gentle removal of meningiomas while maintaining cerebral function.
Neuromas / Schwannomas
The neuromas (also referred to as schwannomas) are benign tumours of the cranial nerves. These mostly display slow growth. The adjacent structures are displaced but have time to adapt themselves to the new location. Therefore, the symptoms take longer to manifest themselves. Even the affected nerve will not immediately display an impaired function. Malignant and fast-growing tumours are rare.
The most common tumour in the posterior fossa is acoustic neuroma, which originates from the Schwann cells of the vestibular nerve. It is, therefore, also correctly referred to as vestibular schwannoma. Because the vestibular nerve extends into the bony internal auditory canal along with the acoustic and motor facial nerves, the tumour increasingly compresses nerves, thereby causing the typical symptoms.
Special techniques implemented at our centre
In our centre, acoustic neuromas are resected in the supine position with head rotation using an endoscopically-assisted microsurgical technique. During surgery, electrophysiological monitoring is always performed in order to check the function of the auditory and facial nerves. The motor facial nerve can be protected – even with large tumours. Using the endoscope, it is possible to view deep into the inner auditory canal. Small residual tumours that are not visible under the microscope can therefore be removed under direct endoscopic control. For larger tumours, we use intra-operative CT in order to control the resection of the tumour during the procedure and exclude surgical complications.
Based on our experience, the use of navigated endoscopic keyhole incisions, which have been functionally tested, leads to better surgical results.
Pituitary adenomas
The pituitary gland is a hormonal control centre. Parent messengers from the brain pass to the pituitary gland via the pituitary stalk and control the hormone production. The pituitary gland produces several vital hormones. These are secreted from the anterior or posterior lobes of the gland into the bloodstream and affect other hormone-producing organs such as the thyroid, adrenal gland, ovaries and testes.
The following hormones are produced in the anterior pituitary lobe:
The adrenocorticotropic hormone (ACTH) passes through the bloodstream into the adrenal cortex, where it controls the distribution of cortisol, a vital stress hormone.
Thyroid stimulating hormone (TSH) acts on the thyroid and regulates the production of L-thyroxine (T4) and triiodo-thyronine (T3).
Follicle stimulating hormone (FSH) and luteinising hormone (LH) regulate sexual development and are responsible for fertility. In men, they act on the testes and stimulate the release of testosterone. In women, these hormones exert their effect on the ovaries and the uterus.
Prolactin is particularly important for women; their production is increased during and after pregnancy. It is responsible for the production of milk during lactation and prevents repeated pregnancy via loss of menstruation.
Growth hormone regulates the size and growth of the body. However, growth hormone does not directly affect body cells; it stimulates the release of insulin-like growth factor I (IGF-1), which is mainly produced in the liver. IGF-1 is then crucial in inducing growth.
Anti-diuretic hormone (ADH) is secreted by the posterior pituitary lobe. ADH prevents the excessive secretion of water by the kidney, thereby regulating fluid balance and the concentration of blood salts.
Tumours of the pituitary gland are almost always benign. They grow slowly and become apparent either through a hormonal disorder or the compression of adjacent structures such as the optic chiasm.
Special techniques implemented at our centre
Pituitary adenomas are usually operated on through the nose via the transnasal access path. In most neurosurgical clinics around the world, the skull base is reached by displacement of the nasal septum. Despite expansion of the nasal cavity with a nasal speculum, the view of the surgical area is limited. It is difficult for the surgeon to assess laterally situated tumour tissue using only a microscope. Without a direct view, there is a risk of damaging important structures such as the optic nerve or carotid arteries. With our endoscopic technique, the lateral structures are also clearly visible. Each step can be reliably monitored throughout the entire procedure. Direct visual control often enables complete removal of the tumour while protecting the healthy structures. An unpleasant tamponade of the nasal cavity is not necessary. Following the procedure, our patients are able to breathe freely through the nose.
In our centre, we cooperate closely with our colleagues from the ORL Centre, who have considerable experience with endoscopy.
Not only do we collaborate during the surgery itself but also during the briefing and preparation. The operation is planned using modern radiological imaging. Using high-resolution computer tomography and MRI, critical structures are recognised in relation to the tumour, thereby determining the optimum endoscopic incision. Before surgery, each patient is pre-examined in the ORL Centre. A smell test and an endoscopic examination of the nose are performed in order to detect any diseases that could influence the operation early on.
In our surgery department, the rhino-neurosurgical team is supported by cutting-edge technology.
The latest endoscopes with cameras and high-definition monitors afford improved light intensity and a vast depth of field with a clear representation of deep structures. It is therefore possible to view the averted structures of the skull base. Navigation devices are routinely using during minimally-invasive surgery, The imaging helps the surgeon to control access and reliably localise the tumour in a gentle manner. If necessary, the effectiveness of the intervention is checked using intra-operative CT or MRI. Residual tumour components can thus be identified and selectively removed.
The latest medical and multidisciplinary cooperation contributes to the safe and gentle removal of pituitary tumours while maintaining quality of life.
Pineal tumors
Pineal tumours arise in the pineal gland. These include the actual tumours of the gland (e.g. pineocytoma or pineoblastoma) as well as tumours of the brain stem (quadrigemina) or the third cerebrospinal fluid chamber (ventricle). Germ cell tumours (i.e. germinomas) also occur in the pineal region. Although they are malignant, they are highly radiosensitive. Because of the anatomical proximity to the cerebral ventricles, pineal tumours often lead to the occlusion of the cerebrospinal fluid pathways and ultimately occlusive hydrocephalus.
Special techniques implemented at our centre
In the case of unclear tumours and occlusive hydrocephalus, we usually perform an endoscopic tumour biopsy. Using the same endoscopic incision, the base of the third ventricle is opened, thereby rectifying the cerebrospinal fluid circulation disorder (ventriculocisternostomy). Radio- and/or chemotherapy is then administered. Alternatively, in the case of appropriate histological results, the tumour, is operated on using an endoscopically-assisted technique. This operation is usually performed in the seated position. After the navigation-based creation of an occipital keyhole incision, the pineal region is reached through the cerebellum with the endoscope. The tumour is then microsurgically resected. With the help of endoscopic optics, the complete tumour resection can be reliably assessed.
For each operation, the brain stem can be examined using electrophysiological monitoring. These techniques, which are routinely used at our centre, contribute to the safe and gentle removal of pineal tumours.
Intraventricular tumours
Intra-ventricular tumours are found completely or partially in the cerebrospinal fluid chambers. Through the closure of the cerebrospinal fluid pathways, they often lead to the damming of the cerebrospinal fluid (hydrocephalus).
In principle, all types of tumours (e.g. astrocytomas, ependymomas, neurocytomas pineal tumours, plexus tumours, craniopharyngiomas, pituitary adenomas, meningiomas.
Special techniques implemented at our centre
By dilating the cerebral ventricles, tumours in the ventricular cavity can usually be accessed via a minimally-invasive endoscopic incision. The thin-layer MRI scan in three levels allows for accurate tumour localisation as well as the assessment of any disturbance in the passage of cerebrospinal fluid The individual incision is meticulously planned and designed with the help of neuronavigation. Especially in a narrow ventricular system, navigation is essential for being able to locate the ventricular cavity in an atraumatic manner. Using intra-operative MRI, complete tumour resection can also be monitored.
These surgical techniques, which are routinely used at our centre, contribute to the safe and gentle removal of ventricular tumours while maintaining cerebral function.
Dermoid and epidermoid tumours
Epidermoids and dermoids consist of different skin cells that remain in the skull during embryonic development. Because they displace healthy structures, they are usually symptomatic. They are often localised in the posterior fossa and grow into all regions of the cerebrospinal fluid space. As a result of their very slow growth, they can reach a threatening size. The use of the endoscopic technique is very advantageous in the removal of the tumour. Using the endoscope parts of the tumour that are not directly visible with a microscope can be gently removed.
Special techniques implemented at our centre
When operating on epidermoids and dermoids, all advantages of the endoscopically-assisted microsurgical technique come into play. Owing to the use of endoscopes, hidden tumour components can be removed without having to extend the minimally-invasive keyhole-like craniotomy and/or displace healthy structures. Neuronavigation helps the surgeon locate the tumour and thus increases the precision of the intervention.
The function of the cranial nerves displaced by the tumour and the displaced brain stem is always checked using electro-physiological monitoring.
These surgical techniques, which are routinely used at our centre, contribute to the safe and gentle removal of dermoid tumours while maintaining cerebral function.
Metastases
Metastases are colonies of a primary malignant tumours outside of the brain. They are the most common brain tumours in the elderly and may occur singly or multiply. The most common primary tumours are:
bronchial carcinoma (40–60%),
mammary carcinoma (10–15%) and
urogenital tumours (5%).
Symptoms include headaches caused by increased cranial pressure, seizures or neurological deficits (e.g. paralysis and sensory, speech, or visual defects). Personality changes and memory disorders are also possible. Metastasis-related neurological symptoms are sometimes the first signs of the primary malignancy. In other cases, the brain tumour is only an incidental finding.
Special techniques implemented at our centre
The aim of surgery is to achieve maximum radicalism in the safest and gentlest way. By applying the latest technology, the risk of post-operative neurological deficits can be minimised. Neuronavigation helps the surgeon locate the tumour and thus increases the precision of the intervention.
The radicality of the resection can also be controlled through the use of intra-operative MRI or CT. During the operation, residual tumour components can be detected in the open skull and then completely removed. Electrophysiological monitoring is used to continuously monitor the integrity of the neurovascular structures – from the functional centres of the brain to the target organ in the periphery. Even in anaesthetised patients, the smallest changes can be accurately assessed. The surgical procedure is then adjusted accordingly. If patients have suffered preoperative epileptic seizures and/or have displayed a pathological EEG (brain wave curve), intra-operative electrocardiography (ECOG) is performed. Potentially epileptic areas can thus be identified and then removed, if possible. If cognitive functions such as language (production and processing) are jeopardised by the procedure, an operation in the awake state is advisable in order to be able to monitor and protect these brain functions during the operation.
These surgical techniques, which are routinely used at our centre, contribute to the safe and gentle removal of cerebral metastases while maintaining cerebral function.
Spinal tumors in and outside the spinal cord
Spinal tumours include all benign and malignant tumours of the spine. They can attack the bones, originate from the nerve root, be present within or outside the spinal canal, or arise directly in the spinal cord. A distinction is made between intramedullary tumours (e.g. astrocytoma or ependymoma) and extramedullary tumours (e.g. neuromas or meningiomas of the spinal cord), which displace the spinal cord. If left untreated, the growth of spinal tumours can lead to spinal cord injury and, ultimately, to paraplegia.
Special techniques implemented at our centre
The aim of surgery is to achieve maximum radicalism in the safest and gentlest way. By applying the latest technology, the risk of post-operative deficits can be minimised. It is important to preserve neurological function in order to prevent surgery-related paralysis, numbness, or other disorders. The constant electrophysiological monitoring of the pathways of the spinal cord and emerging nerve roots is decisive.
The prevention of incision related injuries to the spine and ligaments and, ultimately, subsequent instability also plays an important role. In our centre, tumours are therefore reached via a minimally invasive incision, whereby the muscles are mobilised and traumatised as little as possible. The dynamics and statics of the spine are thus compromised as little as possible.
The use of minimally-invasive techniques with preservation of these structures results in a pain-free recovery and rapid reintegration into personal and professional life.
