Intramedullary tumors of the spinal cord are spinal neoplasms that occur in the cerebrospinal substance. Most often these are gliomas, less often vascular tumors, extremely rarely lipomas, teratomas, dermoid, cholesteatomas, schwannomas, etc. They are manifested by pain syndrome, sensory disturbances, paresis, pelvic dysfunction. Intramedullary tumors are most accurately diagnosed according to MRI and angiography of the spinal cord, as well as the results of examination of neoplasm tissues. Surgical treatment: radical removal of the tumor is performed, if possible, followed by complex rehabilitation therapy.
ICD 10
D33.4 C72 D43.4
General information
Intramedullary spinal cord tumors are quite rare, according to various data, they occupy from 2.5 to 8% of all CNS tumors and no more than 18-20% of spinal tumors. Intramedullary (intracerebral) spinal tumors grow from the substance of the spinal cord. At the same time, they can be located exclusively within the spinal cord, without going beyond its pial membrane, form an exophytic protrusion on the surface of the brain, or grow significantly, filling the subdural space with their mass. Intracerebral neoplasms are most often observed in the cervical segments of the spinal cord. About 70% of intracerebral spinal tumors are gliomas — neoplasms of glial brain cells. Among them, astrocytomas and ependymomas are the most common. The first are observed mainly in childhood, the second — in middle-aged and older people.
Attempts to remove intramedullary tumors have been made since 1911 . However, they were not successful, and back in the 70s of the last century, neurosurgeons, when detecting an intracerebral tumor during surgery, preferred to leave it undetected, but only dissect the dural membrane for decompression of the spinal canal. The use in neurosurgical practice of microsurgical equipment, ultrasound aspirator, surgical laser, precise planning of the operation using MRI significantly increased the possibilities of removing intramedullary tumors and gave hope to many patients. Further improvement of surgical techniques and rehabilitation postoperative treatment is today an urgent problem for specialists in the field of neurosurgery and neurology.
Classification
Depending on the type, gliomas (astrocytomas, ependymomas, oligodendrogliomas, oligoastrocytomas), vascular tumors (hemangioblastomas, cavernomas), lipomas, neurinomas, dermoid tumors, teratomas, cholesteatomas, lymphomas, schwannomas are distinguished among intramedullary spinal neoplasms. Vascular tumors are the second most common after gliomas, their share among all intracerebral spinal tumors is about 15%. Other types of neoplasms are much less common. According to localization, medullocervical, cervical, cervical-thoracic, thoracic, lumbar neoplasms and tumors of the epiconus and cone are classified. Intramedullary spinal cord tumors can be metastatic, which occurs in breast cancer, lung cancer, renal cell carcinoma, melanoma, etc.
From a neurosurgical point of view, it is important to classify tumors by the type of their growth into diffuse and focal. Diffusely (infiltratively) growing neoplasms do not give a clear distinction with spinal tissues, their prevalence varies from a lesion of one segment to a violation of the structure of the entire spinal cord. Diffuse growth is typical for astrocytomas, glioblastomas, oligodendrogliomas, and some ependymomas. Focally growing tumors can cover from 1 to 7 spinal segments, but they are clearly delineated with spinal cord tissues, which favors their radical removal. Focal growth is characterized by ependymomas, hemangioblastomas, cavernous angiomas, lipomas, teratomas, and neurinomas.
In surgical practice, the classification of itramedullary tumors into exo- and endophytic is also used. Exophytic neoplasms spread beyond the pial membrane and continue to grow on the surface of the spinal cord. Such tumors include hemangioblastomas, lipomas, dermoids, teratomas. Endophytic formations grow inside the spinal cord without leaving its pial membrane. Endophytic are ependymomas, astrocytomas, metastatic tumors.
Symptoms
Intracerebral spinal tumors are often characterized by a relatively slow development of the clinical picture with the existence of a long period of mild manifestations. According to some data, the time from the appearance of the first symptoms to the patient’s referral to neurosurgeons varies from 3 months to 11 years, but on average it is 4.5 years. A typical symptom of the debut of a tumor is pain along the spine in the area of the location of the neoplasm. It is protopathic in nature — prolonged aching and dull pain, the exact localization of which patients find it difficult to specify. A distinctive feature of the pain is its appearance in a horizontal position and at night, while the pain associated, for example, with osteochondrosis of the spine, on the contrary, in the supine position decreases and passes. A similar pain syndrome is observed in about 70% of cases.
In 10% of patients, the pain has a radicular character — acute baking or burning “lumbago” going in a downward direction along the course of innervation of 1-2 spinal roots. Rarely intramedullary tumors manifest the appearance of dysesthesia — sensory disorders in the form of cold/heat in 1 or more limbs. Usually, the clinic of intracerebral spinal neoplasms includes violations of surface types of sensitivity localized according to the level of lesion (feeling of pain and temperature) while preserving deep ones (tactile sensations and positional sensitivity). In some cases, the primary symptom is weakness in the legs, which is accompanied by increased muscle tone and muscle atrophy. When the cervical and thoracic spinal segments are affected, pyramidal manifestations (spasticity, hyperreflexia, pathological stop signs) can be observed quite early.
The clinic of intramedullary tumors varies according to their location along the length of the spinal cord. Thus, medullocervical neoplasms are accompanied by cerebral symptoms: signs of intracranial hypertension, ataxia, visual disturbances. Tumors of the cervical segments often debut with occipital pains, followed by the addition of paresis and hypesthesia in one arm. Lower paraparesis occurs after several months or even years, and pelvic dysfunction occurs only in the later stages. Intramedullary tumors of thoracic localization are often manifested by the appearance of mild scoliosis. Then there are pains and tonic tension of the paravertebral muscles, discomfort during movements. Sensory disorders are not very characteristic, paresthesia and dysesthesia predominate among them. Pelvic disorders are late manifestations. Intramedullary epiconus/cone tumors are characterized by early occurrence of pelvic dysfunction and impaired sensitivity of the anogenital zone.
Diagnostics
Ependymomas and astrocytomas that have reached large sizes can give an extension of the spinal canal that is fixed during frontal radiography of the spine, but the presence of this X-ray sign only allows you to suspect a tumor. Examination of the cerebrospinal fluid gives the neurologist the opportunity to exclude inflammatory lesions of the spinal cord (myelitis) and hematomyelia. In favor of the tumor process, the presence of protein-cell dissociation and pronounced hyperalmubinosis indicates. Tumor cells in the cerebrospinal fluid are a rather rare find. Objectification of neurological changes and dynamic observation of them is performed by methods of electroneuromyography and the study of evoked potentials.
Previously, the diagnosis of spinal neoplasms was carried out using myelography. Currently, it has been replaced by tomographic methods of neuroimaging. The use of CT of the spine makes it possible to differentiate intramedullary tumors of the spinal cord with its cysts, hematomyelia and syringomyelia; to diagnose compression of the spinal cord. But the most informative way to diagnose spinal tumors today is MRI of the spine.
MRI allows us to assume the type of tumor, to determine its diffuse or focal nature, to establish the exact localization and prevalence. All these data are necessary not only from a diagnostic point of view, but also for adequate planning of surgical treatment. T1-mode is more informative in relation to cystic and solid components of the neoplasm, T2-mode — in relation to cysts and visualization of cerebrospinal fluid. The use of contrast greatly facilitates the differentiation of the tumor from the surrounding edematous tissues.
Diagnosis of vascular intramedullary neoplasms requires spinal angiography. Today, the method of choice is vascular CT or MRI angiography. For the purpose of preoperative determination of the vessels feeding and draining the tumor, the use of the latter is preferable. The final verification of an intramedullary tumor is possible only by the results of histological examination of its tissues, which are usually taken intraoperatively.
Treatment
The effectiveness of radiation therapy against intramedullary tumors is questionable, since it entails radiation damage to the spinal cord, which is more sensitive to radiation than cerebral tissues. In this regard, despite all the difficulties of the operation, the surgical method is the main one. The volume of removal of an intramedullary tumor is dictated by its type, growth pattern, location and prevalence.
Access to the tumor is laminectomy. With endophytic tumors, a myelotomy is performed — an autopsy of the spinal cord, with exophytic neoplasms, removal begins with their exophytic component, gradually deepening into the spinal cord. At the first stage of removal of vascular tumors, coagulation of the vessels feeding them is performed. After the most radical microsurgical excision of tumor tissues using intraoperative ultrasonography, the search for tumor remnants and foci of its additional growth is carried out. The surgical intervention ends with suturing the dural meninges, creating a corporodesis and fixing the spine with plates and screws. Removal of hemangioblastomas is possible by embolization of their vessels.
Focal intramedullary spinal cord tumors can be removed most radically, diffuse — only partially. However, many neurosurgeons note the positive effect of the operation in diffuse neoplasms. The main problem of the postoperative period is edema of brain tissues, in connection with which, after surgery, there is an aggravation of neurological symptoms, and with medullocervical localization of the tumor, there is a risk of dislocation syndrome with the brain wedging into the occipital foramen and the death of the patient.
In most cases, postoperative neurological changes regress in the period from 1 to 2 weeks. With a deep neurological deficit, this time increases. In some cases, the additional neurological deficit formed as a result of the operation has a persistent character. Since the depth of postoperative neurological changes directly correlates with the neurological deficit existing before surgery, many surgeons recommend early surgical treatment.
Prognosis
The prognosis of intracerebral spinal neoplasms is ambiguous and is determined by the characteristics and parameters of tumor growth. The main complication in the long—term period after radical surgical treatment is the continued growth and recurrence of the tumor. Ependymomas have a relatively favorable prognosis. There is evidence of the absence of relapses 10 years after the operation. Astrocytomas give less opportunity for radical removal, in half of patients they recur within 5 years after surgery. Teratomas have an unfavorable prognosis, since they are prone to malignancy and are capable of producing systemic metastases. The prognosis of metastatic intramedullary tumors depends on the primary focus, but in general does not inspire much hope.
The degree of recovery of neurological deficit during a successful operation largely depends on the severity of symptoms before the start of surgical treatment, as well as on the quality of rehabilitation therapy. There are numerous cases when patients who were operated on for ependymoma in a timely manner returned to their normal work.