Intramedullary tumor of the spinal cord

Among many spinal neoplasms, intramedullary tumors of the spinal cord are often found, which in most cases are represented by gliomas and somewhat less frequently by lipomas, teratomas and other tumor processes. Low malignant processes also occur among them.

The prevalence of intramedullary tumors is relatively small - no more than 8% among all such pathologies of the central nervous system. The disease develops on the basis of the spinal substance, can be localized within the boundaries of the spinal cord or extend beyond the parenchyma. Obstructing the flow of liquor may contribute to the formation of a fistula. Techniques for surgical correction of the problem are constantly improving: surgeons are increasingly using microsurgical instruments, surgical laser devices, planning interventions with visualization and MRI. Nevertheless, dealing with intramedullary spinal cord tumors is a challenging process even for modern surgery. [1]

Epidemiology

Intramedullary tumor of the spinal cord is a relatively rare phenomenon. According to various statistical information, the incidence ranges from 3 to 8% among all tumor processes involving the central nervous system and up to 19% among all cerebrospinal neoplasms.

An intramedullary tumor develops from the spinal cord substance. It often grows locally and does not leave the pial membrane of the spinal cord, may form an exophytic bulge on the cerebral surface or spread to the surrounding tissues, extending into the subdural space.

In the majority of patients, intramedullary tumors are found in the cervical spinal cord. The vast majority of such masses (seven out of ten) are gliomas formed on the basis of glial brain cells. Among gliomas, the most common are:

• Astrocytomas (more common in pediatric patients);
• ependymomas (affect mainly middle-aged and elderly people).

Scientists have been working on the treatment of intramedullary tumors for more than a century. But for a long time, operations were performed without much success: the main focus of such interventions was the dissection of the dura mater in order to eliminate excessive pressure on the spinal cord canal. The complete removal of the pathological focus was out of the question. Only about fifty years ago, neurosurgeons began to use in their practice microsurgical tools, ultrasound and laser technology, magnetic resonance imaging. This made it possible to accurately plan the surgical process and made it possible to remove even such complex neoplasms. [2]

Causes of the an intramedullary spinal cord tumor.

Reliable causes of intramedullary tumors of the spinal cord are still unknown, although experts have already identified some risk factors for the development of the disease. It should be borne in mind that glial neoplasms often develop from tumor metastases that have moved from other organs and only after a while are found in the nervous tissues. [3]

• exposure to ionizing radiation (including during radiotherapy);
• presence of similar pathologies in the family (close relatives);
• the influence of potential carcinogens (pesticides, polyvinyl chloride, etc.);
• weak immune system;
• hereditary diseases (Lynch, Li-Fraumenti, Turcot, Cowden syndromes, neurofibromatosis types I and II).

Risk factors

Most people are aware of the risk factors associated with the development of malignant tumor processes. These include smoking, poor nutrition, chemical and radiation exposure, hereditary predisposition, hyperinsolation, etc. [4]

The neoplasm can either primary develop in the spinal structures or metastasize to the spine from other organs. The spinal column has a well-developed circulatory system, and malignant cells can easily enter with the bloodstream from other maternal foci.

It is especially important for women to have regular breast examinations and cytologic smears to detect cervical cancer. All patients should undergo regular fluorography, blood and stool tests (for hidden blood to detect colon cancer).

Another common risk factor is spinal column injuries, deformities, and birth defects. [5]

Pathogenesis

Intramedullary tumors differ depending on the type of spinal mass:

• Gliomas:
  • Astrocytoma;
  • ependymoma;
  • oligodendroglioma;
  • oligoastrocytoma.
• Vascular neoplasms:
  • cavernoma;
  • hemangioblastoma.
• Fatty and dermoid tumors, neurinomas, teratomas, lymphomas, cholesteatomas, schwannomas.

The localization of pathological formations also differs:

• medullocervical area;
• cervical, cervicothoracic area;
• the thoracic region;
• lumbar spine;
• epiconus and conus.

An intramedullary tumor can metastasize on its own or be a metastasis of other tumor processes (in particular, breast or lung cancer, renal cell cancer, melanoma, etc.). [6]

The growth of the neoplasm can be diffuse or localized.

In diffuse or infiltrative spread, there is no clear border with cerebrospinal structures, and single or multiple spinal cord segments may be affected. Such spread is characteristic of glioblastoma, astrocytoma, oligodendroglioma.

In focal growth, the focus diverges into 1-7 cerebrospinal segments, but in all cases there is a clear border with healthy spinal cord structures, which facilitates complete resection of the pathology. Such growth is typical for most ependymomas, as well as for cavernous angiomas, lipomas and neurinomas, hemangioblastomas and teratomas. [7]

Symptoms of the an intramedullary spinal cord tumor.

Intramedullary tumor of the spinal cord develops relatively slowly, with symptoms increasing gradually over a long period of unexpressed, "erased" signs. According to general statistical information, after the appearance of the first symptoms, few patients immediately come to the doctors. Usually it happens not earlier than after several months or even years. The average period of contacting a doctor is about 4-5 years.

The first signs usually (in 70% of cases) begin with pain syndrome, which begins to bother in the area of the affected spinal segment. The main characteristics of pain are prolonged, aching, non-acute, diffuse, more often nocturnal, with a tendency to intensify when lying down.

Every tenth patient has radicular pain: sharp, burning, "shooting", radiating to the lower part of the body and extremities. In some cases, deterioration occurs in the form of sensory disturbances - mainly tactile and positional sensitivity is affected. Patients note muscle weakness in the lower extremities, hypertonicity, up to muscular atrophy. If the pathological focus is localized in the cervical and thoracic spine, pyramidal disorders (changes in tone, hyperreflexia) dominate.

Clinical manifestations depend on the site of spinal cord involvement by the intramedullary tumor. For example, in medullocervical focus, cerebral symptoms are noted:

• clinic of increased intracranial pressure;
• visual impairment;
• ataxia.

Intramedullary tumor of the cervical spinal cord makes itself known by constant pain in the occipital part of the head, which eventually develops into sensory disorders, paresis of one of the upper extremities. Further, the risk of developing lower paraparesis, pelvic organ dysfunction (more typical for late stages of the disease) increases.

A thoracic intramedullary spinal cord tumor often begins with the patient having a slight curvature of the spine (more commonly scoliosis). Over time, pain and tension (tone) of the paravertebral musculature appear. Movement becomes limited, uncomfortable. Among sensory disorders, mainly dysesthesias and paresthesias are noted. [8]

Patients with epiconic or cone intramedullary tumors have earlier pelvic organ dysfunction and altered groin sensitivity.

Among the most common symptoms:

• back pain (worsens when lying down, increases with coughing, sneezing, straining, tends to irradiate and is not eliminated by analgesics);
• Sensory disturbances (especially pronounced in the extremities);
• motor disorders (muscle weakness, difficulty walking, coldness in the extremities, incontinence of urine and feces, muscle paresis and paralysis, muscle twitching).

Stages

Intramedullary tumor develops sequentially and goes through three stages of development: segmental, complete transverse spinal cord lesion, and radicular pain stage.

Intramedullary tumors arise on the basis of gray spinal cord substance. The segmental stage is caused by the appearance of dissociated segmental disorders of superficial sensitivity according to the level of localization of the neoplasm.

The stage of complete transverse spinal lesion starts when the pathological focus sprouts into the white matter. Segmental sensory disturbances are replaced by conductive ones, motor and trophic disorders appear, dysfunction of pelvic organs occurs.

The radicular pain stage is characterized by the exit of the neoplasm beyond the boundaries of the spinal cord. Sprouting into the roots occurs, which is accompanied by the appearance of radicular pain.

Complications and consequences

Complications due to intramedullary spinal cord tumor can be divided into several groups:

• Instability of the spinal column, inability to perform supportive activities, including walking and standing.
• Complications associated with compression of spinal structures and nerves (pain, weakness in the limbs, complete and incomplete paralysis, pelvic organ dysfunction).
• Complications associated with the need for prolonged bed rest (thrombosis, congestive pneumonia, urogenital infections, etc.).
• Intra and postoperative complications associated with the crossing of nerve structures, pelvic floor integrity violations, damage to large vessels, blood loss, perforation, infection, etc.

Often patients have sensory disturbances in the groin area and lower extremities, difficulty walking, sexual, urinary function and defecation are impaired.

Diagnostics of the an intramedullary spinal cord tumor.

All cases of intramedullary spinal cord tumors use a comprehensive diagnostic approach that includes procedures such as:

• Neurological examination: based on the clinical symptoms and complaints of the patient, the neurologist can suspect the presence of a particular pathology.
• X-ray of the vertebral column: not sufficiently informative method, but allows to confirm the suspicion of a tumor process.
• Analysis of cerebrospinal fluid: allows to exclude inflammatory phenomena in cerebrospinal structures.
• Electromyography, evoked potential diagnostics: help to detect obvious neurological disorders and monitor them in dynamics.
• Computed tomography: helps to identify intramedullary tumor, distinguish it from other similar pathologies.
• Magnetic resonance imaging: provides complete information about the type of the focus, its localization and distribution, allows you to determine the treatment tactics.
• Spinal angiography: allows differentiation with vascular neoplasms.

In addition, blood and urine tests are performed as part of general clinical examinations. Blood may be taken to assess the level of oncomarkers.

Instrumental diagnosis can be as informative as possible, but the final diagnosis of an intramedullary tumor is made only after histological examination of the tissues that are removed during surgery. [9]

Differential diagnosis

Analysis of cerebrospinal fluid allows to exclude inflammatory processes - in particular, myelitis, as well as hematoma of the spinal cord. The presence of intramedullary tumor is indicated by the presence of protein-cell dissociation and intense albuminosis (painful predominance of protein substances). Cancer cells are rarely found in the cerebrospinal fluid.

A few decades ago, myelography was a particularly common diagnostic procedure. Today, it has been almost completely replaced by tomographic methods. For example, CT helps to distinguish an intramedullary tumor from a cystic mass, hematomyelia or syringomyelia, as well as to detect spinal cord compression.

Magnetic resonance imaging is also used for differentiation. T1 mode helps to distinguish between solid masses and cysts, while T2 mode is effective in relation to cerebrospinal fluid and cysts. It is recommended to perform the study with the use of contrast agents. [10]

Treatment of the an intramedullary spinal cord tumor.

Since intramedullary tumor is considered to be a relatively rare pathology, specialists do not have scientifically based proven effective treatment tactics. Therefore, the treatment plan is individualized, taking into account the opinion of experts and the medical consensus.

Patients with asymptomatic course of the disease (if the intramedullary tumor is detected accidentally during MRI) are prescribed dynamic monitoring and regular MRI every six months. Neurological symptoms or MRI symptoms of neoplasm progression are considered indications for surgical radiotherapy.

In all other cases, a first detected intramedullary tumor should be surgically removed. The direction of surgery is as follows:

• Radical resection for limited neoplasms such as ependymoma, piloid astrocytoma, hemangioblastoma;
• Maximize volume reduction for infiltrative neoplasms such as astrocytoma, anaplastic astrocytoma, ganglioastrocytoma, and glioblastoma.

Any surgical approach should not harm the functional status of the patient.

Surgical treatment is performed in a neurosurgical clinic (department), preferably with the possibility of neurophysiological imaging in the form of motor evoked potentials. The operating surgeon should have experience in neuro-oncologic surgeries on the spine and spinal cord. In pediatric patients, access is performed by laminotomy or laminoplasty.

In the postoperative period, the patient is administered steroid drugs (Dexamethasone) in the form of intramuscular injections on about the sixth day after the intervention. The average dose for an adult is 16 mg per day, withdrawal of the drug is gradual. [11]

After operated upper cervical tumors or cervico-medullary neoplasms, the patient spends the first 24 hours in the neurological intensive care unit.

Rehabilitation measures are started as soon as possible, as soon as regression of spinal pain is noticeable. MRI monitoring to determine the effectiveness of the operation is performed 24 hours or as early as 4-6 weeks after the intervention.

The efficacy of radiation exposure on intramedullary tumors has not been proven. Radiation causes radiation damage to the spinal cord, which is more sensitive to it than cerebral structures. Taking this into account, specialists prefer a safer and more effective surgical intervention, although more complicated. [12]

Surgical treatment

Patients with an intramedullary spinal cord tumor undergo a laminectomy, which involves removal of the vertebral arch. This expands the canalicular cavity and eliminates compression, as well as provides access to spinal structures.

Endophytic masses are an indication for myelotomy - exposure of the spinal cord, and exophytic ones are removed by gradual deepening.

The first stage of tumor removal involves coagulation of the blood vessels that feed it. The tumor tissue is radically excised using background ultrasonography. It is mandatory to search for possible remaining tumor particles. The operation is completed by suturing the dura mater, providing spondylosis and vertebral fixation with screws and plates. Hemangioblastomas are removed using vascular embolization. [13]

Focal neoplasms are better suited to radical removal, unlike diffuse neoplasms, which in most cases can only be partially removed.

The most common postoperative problem is cerebral edema, which aggravates the neurologic picture. In patients with medullocervical foci, there is an increased risk of dislocation with cerebral tissue entering the occipital foramen and subsequent death.

In most patients in the postoperative period, neurologic symptoms fade within 7-14 days. If we are talking about severe neurologic insufficiency, this interval increases up to 21 days. In some cases, neurologic disorders acquire a steady course. [14]

Medications

Within the framework of palliative treatment, aimed at alleviating the suffering of the patient and improving his quality of life, when radical methods are impossible or inappropriate, painkillers, anti-inflammatory and other drugs are prescribed, depending on the indications.

A list of the most commonly used medicines is shown in the table below:

Non-opioid analgesics and non-steroidal anti-inflammatory drugs
Diclofenac sodium	The course dose for 2 weeks is 56 tablets of 50-75 mg or 28 ampoules	Drugs are prescribed taking into account gastrointestinal and cardiovascular risk. The use of antacid and anti-ulcer drugs is recommended at the same time.
Ibuprofen	200-400 mg three times a day for 14 days
Paracetamol	500 mg 3-5 times a day
Ketoprofen	The course dose for 2 weeks is 14-42 capsules, 28 ampoules or 28 suppositories
Opioid analgesics
Tramadol	50 mg, 1-3 times per day, at the discretion of the physician	Frequent side effects: decreased heart rate, nausea, constipation, bronchospasm, headache, increased sweating. Long-term use may lead to drug dependence and withdrawal.
Morphine	In the form of solution for injection in ampoule 1% 1 ml, according to the individual scheme
Trimepyridine	In the form of solution for injection in ampoule 1-2% by 1 ml, according to the individual scheme
Hormonal agents
Dexamethasone	As solution for injection 4-8 mg/mL of dexamethasone phosphate (dinatrium salt), ampoules of 2 ml each	The drug is used cautiously, especially if prone to thrombosis.
Antiemetics
Metoclopramide	In the form of solution for injection 0.5%, 10 mg/2 ml, 5 mg/ml, or tablets of 10 g, according to an individually formulated scheme	Causes drowsiness, sometimes extrapyramidal disorders.
Sleeping pills and anxiolytics
Diazepam	As solution for injection in ampoules of 10 mg/2 ml, or as tablets of 5 mg	Possible side effects: dry mouth or, conversely, increased salivation, as well as heartburn, nausea, constipation, jaundice.
Phenazepam	Tablets of 0.5-1-2.5 mg, an average of 21 tablets per course
Antidepressants
Amitriptyline	Injectable solution of 10 mg/1 ml, 20 mg/2 ml, or 25 mg tablets	With prolonged use may cause convulsions, urinary retention, glaucoma. Amitriptyline should not be taken in combination with MAO inhibitors and Cisapride.
Anticonvulsants
Carbamazepine	200 mg tablets, as indicated	Among the most common side effects: dizziness, visual doubling, drowsiness, vestibular and coordination disorders.
Pregabalin	In capsules of 75-150-300 mg, according to the individual scheme
Phenobarbital	In the form of 50-100 mg tablets, you will need 28 tablets for a two-week course
Antianginal drugs
Nitroglycerin	As sustained-release tablets 6.5 mg	Use may be accompanied by nausea, diarrhea, bradycardia, general weakness, headache and dizziness, sometimes - allergies.
Propranolol	Tablets 10-40 mg, as indicated
Diuretics
Furosemide	As a 1% injectable solution of 20 mg/mL, or 40 mg tablets	Side effects include hemodynamic disorders, dizziness, dehydration, muscle spasms, vascular collapse, hearing and vision impairment.
Antispasmodics
Drotaverine	Tablets of 40-80 mg, or 2% injectable solution of 40 mg/2 ml, 20 mg/mL	Long-term use may cause headaches, vertigo, insomnia. Frequent side effects: decrease in blood pressure, nausea.
Papaverine hydrochloride	Injectable solution 2% ampoules of 2 ml, as indicated
Laxatives
Bisacodyl	In case of tendency to constipation, rectal suppositories 10 mg are administered in the evenings	Frequent use should be avoided, which is fraught with violations of water-electrolyte balance, development of muscle weakness and arterial hypotension.
Antiepileptic drugs
Clonazepam	As 0.5-0.25-1 or 2 mg tablets, according to an individualized regimen	With a prolonged treatment course, it is possible to develop drug dependence, and with withdrawal - withdrawal syndrome.

Prevention

Since there is no specific prevention of intramedullary tumors, experts recommend paying attention to general preventive anti-tumor measures. Such measures include a number of complex factors.

• Smoking is a risk factor for various types of cancerous tumors, including intramedullary neoplasms. This includes both active and passive inhalation of tobacco smoke.
• Improper nutrition, overweight and obesity have always been considered as special factors that provoke the development of cancer. The abundance of preservatives and other carcinogens in the diet, as well as red meat and smoked meat, against the background of excessive load on the spinal column can lead to irreparable consequences.
• Alcohol dependence by the degree of toxicity is equal to avid smoking. Alcohol plays a particularly negative role in the presence of other risk factors.
• Infectious-inflammatory pathologies create favorable conditions for the subsequent development of tumor processes. Human papillomaviruses, viral hepatitis, parasitic infections are considered particularly dangerous in this regard.
• Poor ecology, air, water and soil pollution have a subtle but persistent negative impact on the body.
• Occupational hazards, contacts with chemical and other potentially harmful substances have causal links with the development of oncopathology.
• Ionizing radiation poses a high risk to all people, especially children. Even sunlight can have carcinogenic effects, so avoid excessive sunbathing, including tanning.

In addition, it is important to regularly visit the doctor for routine diagnostic and preventive measures. A timely detection of pathology is easier to cure.

Forecast

The prognosis of intramedullary tumor is not unambiguous due to the different characteristics and course of the tumor process. The development of complications worsens the outcome of the disease, in particular, aggressive growth and recurrence of the neoplasm.

A relatively favorable course is characteristic of ependymomas, which are more prone to a recurrence-free course.

Astrocytomas are worse with surgical treatment, so they often recur as early as five years after surgery.

There are frequent unfavorable outcomes in teratomas due to their widespread malignancy and systemic metastasis. When metastases form, the prognosis depends largely on the course and the state of the maternal focus, but in most cases there is little chance of recovery.

Neurological insufficiency may manifest itself to varying degrees, which depends on the stage of pathology, the quality of treatment, and the completeness of rehabilitation measures. In many patients, intramedullary spinal cord tumor was completely cured, the ability to work was restored, and patients returned to their normal way of life.