Spinal tumors are tumors of the spinal cord (the downward continuation of the brain through the hole in the skull called the foramen magnum), tumors of the nerves (nerves arise in the spinal canal and then exit the spinal canal through the foramina that are formed by two articulating vertebrae) that arise from the spinal cord and are completely or partially within the spinal canal (a space within the bony structure of each vertebrae through which the spinal cord passes) and tumors of the vertebral column or the bony structure of the spine. Humans usually have 33 vertebrae, 7 cervical (situated in the neck), 12 thoracic (these are at the back of the chest with the ribs attached) 5 lumbar (supporting the back of the abdomen), 5 sacral vertebrae (usually fused into one) and 4 coccygeal vertebrae that is also fused together to forms the tail bone. Each individual vertebra, other than the ones fused, articulates with the vertebra above and below with the help of the intervertebral disc in front and articular facets at the back, supported by ligaments and muscles on all sides. The spinal cord starts as the brainstem exits from the foramen magnum and ends in the adult at the level of the first lumbar vertebrae. Below that the central canal continues downwards as do all the nerve roots to exit from the respective foramina. The bunch of nerve roots along with the central canal below the spinal cord popularly known as the cauda equina as it resembles a horse’s tail.
The nomenclature of spinal tumors depends on two things- one is their location with respect to the spinal column- so cervical, thoracic, lumbar and sacral and the position with regard to the spinal cord and its covering – the dura. The intra dural tumors arise inside the dural covering. They may either be in the space between the dura and the spinal cord– intradural extra medullary (includes tumors of the arachnoid membrane or meningiomas, tumors of the nerve roots as they leave the spinal cord- neurofibromas and schwannomas) or may arise from the ependymal lining at the centre of the spinal cord or the glial cells (supporting cells of the brain and spinal cord) limited to the substance of the spinal cord, referred to as intramedullary tumors. Intradural extramedullary tumors are usually benign while intramedullary tumors are usually low grade cancers. However, exceptions are present in both cases. Rarely tumor-like malformations may be seen within the substance of the spinal cord, which are overwhelmingly benign or congenital in nature. Tumors outside the dura or extradural tumors when affecting the bony skeleton alone are usually cancerous and are secondary in nature. If they arise from the nerves outside the dura, often extending along the nerve to present as a mass within the chest or abdominal cavity, they are usually benign.
Back pain is almost invariably present. Classical teaching suggests that the pain is intense, located in the back and is more severe at night often waking the patient up from sleep. At times, especially in the elderly, a trivial fall may cause the fracture of a vertebra that has been weakened by cancerous deposits that have spread from other parts of the body. Other symptoms that may indicate a spinal tumor include:
In the vast majority of cases the causes of spinal cord tumours remain unknown and they comprise only 10-15% of all primary tumours of the central nervous system (brain and spinal cord). Meningiomas of the spinal cord are more common in women, and are probably due to the female hormone oestrogen. Spinal tumours do not run in families per se, unless the patient suffers from Neurofibromatosis– where benign tumours form in the arachnoid layer (meningiomas), in the substance of the spine(gliomas) or the nerves themselves- neuromas and schwannomas. Von Hippel-Lindau’s disease– another genetically transmitted disease that leads to the formation of benign tumours of the blood vessels that affect the brain and the spinal cord. These are also associated with tumours of the retina, kidney and adrenal glands. Spinal cord lymphomas (arising from lymphocytes, a type of white blood cell) are frequently associated with immunodeficiency (HIV).
The definitive diagnosis of the presence of a spinal tumor is the MRI scan. A histopathological examination of the biopsy (tissue) specimen then confirms the nature of the lesion. The MRI scan gives the physician excellent information on the location and extent of disease, and its possible aetiology. The MRI scans are completely safe and rely on the delivery of a radiofrequency pulse to a magnetic field, in which the patient lies. However, sometimes, X-Rays of the spine may be done because it is easier and quicker to arrange. These are usually sensitive enough only for the diagnosis of fractures of the vertebral bodies. Erosion of the bone caused usually by slow growing spinal tumours may also be detected on X-Rays or CT scans. When a secondary deposit is suspected (spread from a primary tumor elsewhere in the body) a PET scan may be done to assess the extent of disease.
Treatment of spinal cord tumours depends on a few major factors- the degree of neurological deficit, the suspected aetiology of the tumor, the duration of symptoms and the age of the patient. The most important factors in neurological recovery are the extent of paralysis at presentation and the duration of the symptoms. The general teaching is that surgery is performed to preserve neurological function, and any improvement can be considered to be a bonus. It is also generally believed that for any improvement to occur, decompression of the spinal cord must be done within 24 hours of onset of paralysis. However, sometimes surgery is undertaken even if no neurological recovery is expected for stabilising the spine (which helps mobility in a wheelchair, if needed) or reduction of pain.
Surgery: Surgery is usually the first modality used, but may be different if the lesion is suspected to be a metastatic lesion from somewhere else in the body. In those cases, radiotherapy or even chemotherapy may be used as first line therapy. The extent of surgery often depends on the end goal.
For malignant tumours affecting the spinal column, (the bony skeleton in which the spinal cord is housed) en-bloc curative resections are be possible, where the diseased vertebrae along with the tumor is removed and replaced by a metal (usually titanium) or carbon fibre cage. Access to the tumor is gained through the front or the side of the spine (neck, chest or abdomen, depending on the location of the lesion). This fixation may be further augmented by instrumentation (screws) inserted through the pedicles approached from the back. If there is weakness and/or numbness in the arms or legs caused by the tumor pressing the spinal cord, the compression of the spinal cord may be relieved by removing the spinal lamina (laminectomy or decompression). However, such front and back (or 360 degrees) surgeries are long and complicated with significant blood loss ( in cancer patients). So patients who are frail or elderly or have multiple co-morbid factors do not recover well from such extensive procedures. Hence, simple decompressive surgeries are also done as stand-alone procedures. In patients who are completely paralysed or deemed to be terminally ill from malignant disease, radical or decompressive surgery is, more often than not, counterproductive. If the nature of the lesion is unknown and the aim of surgery is to obtain a biopsy for a pathological diagnosis, then this can be performed percutaneously with a needle using the CT or X-Ray guidance. Patients who are in intractable pain due to tumor deposits in the spine may benefit from a percutaneous vertebroplasty- a procedure done under local anaesthesia and involves the injection of bone cement into the lesion. In patients with metastatic malignant tumors that are known to be radio-sensitive, radiotherapy may be the first line of choice. Radiotherapy may also be used in palliative care to alleviate pain. Neurological improvement following radiotherapy is very rare.
For almost all tumours that arise in the spinal cord and the roots that emerge from the cord, surgery is the first line of treatment. The aim of surgery is to provide a tissue sample for histopathological examination to make a diagnosis, remove as much of the tumor as safely possible and relieve the pressure on the spinal cord. Tumors arising within the spinal canal are usually approached through a laminectomy or a laminoplasty (where the lamina is placed back after removal); or rarely by removing the body of the vertebra at the front of the spinal column. Tumors within the substance of the spinal cord are approached by incising the spinal cord in the centre ( a midline myelotomy). Tumors of the nerve roots may not need an incision on the spinal cord per se but may involve more complex 2-step surgical procedures if part of the tumor is within and part of it outside the spinal canal. Usually, if benign tumors are removed completely, nothing more needs to be done. However, if there is a remnant that has been left behind to avoid a loss of function or due to a surgical limitation, radiotherapy to the remnant may be considered. Malignant tumors are always followed by radiotherapy to the affected area mainly to avoid recurrence.
It is very important to ask the doctor questions before the operation. This may be difficult in the middle of a very busy clinic, so time needs to be sought so that you feel comfortable to go ahead with surgery.
Before Surgery
And finally, ask about cost. Budget? And what is covered? . Though cost will be a major factor that decides where you have treatment, it is always good to get a clear picture of what is being offered for the price.
After Surgery
One of the major issues that present with any tumor to the spine is the possibility paralysis of either the legs or all four limbs along with the loss of bladder and bowel control. In most extreme cases, damage to the phrenic or breathing nerve located in the cervical spine (neck) may lead to an inability to breathe. This will result in being attached to a ventilator 24 hours of the day. Paralysis is a truly catastrophic consequence and will often result in the inability to cope both for the patient and his/her caregivers. It is not uncommon for these patients to be depressed and have suicidal thoughts. It often does take time to be able to assimilate all the information which is often given to them in a very short period of time. Caregivers find it overwhelming as care has to be provided round the clock. In addition to all this, the diagnosis of cancer may loom. However difficult, it is important to stay positive and call on family and friends for both physical and psychological support. Talking often helps get things into perspective and for the realization that all is not lost, however grim it may look. Professional help in the form of counselling services provide comfort to the patient and the caregiver. Occupational therapists may be able to suggest ways to modify the home that makes access and living easier with modifications necessary accessibility.