Tumors of the Spinal Cord

Tumors of the spinal cord are divided into extradural and intradural. Intradural tumors are further subdivided into extramedullary (arising outside the spinal cord) and intramedullary (arising within the cord).

Common extra medullary tumors are neurofibroma, meningiomas sarcomas, lipomas, chordomas and teratomas while intramedullgy tumours comprise of ependyomas, spongioblastothas medulloblastomas, oligodendrogliomas, ganglioneuromas, haemangioblastomas and astroblastomas. Uncommonly tuberculoma, gumma and leukemic deposits may form part of intramedullary compression.

Extramedullary tumors

These arise outside the substance of the spinal cord and produce symptoms due to pressure on nerve roots or compression of the spinal cord or occlusion of spinal blood vessels.

Pain in distribution of nerve roots and of variable severity is the presenting symptom. It is aggravated by movement, sneezing or coughing. To start with the symptoms are confined to one half of body but soon these become bilateral and sensory 9igns followed by motor weakness of the limbs develops. Gait becomes unsteady and patient may exprience difficulty in walking. Bladder control is effected.

The commonest tumors in this group are meningiomas and neurofibromas.

Meningioma arises either from the spinal roots or spinal meninges and is in the form of firm, oval pinkish tumor which is either smooth or nodular in outline. It may become calcified.

Meningioma is mainly seen in the age group of 30-60 years affecting women more than men. Common site is the thoracic region lying posterior to spinal cord.

Neurofibromas – These usually arise from spinal roots, the posterior roots more frequently than the anterior. These may be solitary or multiple and may or may not be associated with generalized neurofibromatosis.

The thoracic region of the cord is the commonest site. It may be situated partly within and partly outside the vertebral canal with constriction at intravertebral foramen giving the tumour a dumb bell shape.

Roots pain is the earliest symptom and these are of severe intensity. Symptoms to start with are unilateral. Irritation of spino thalamic tracts may produce spasms of intense pain.

As the symptoms progress picture of Brown-Sequard syndrome may result (loss of appreciation of posture and passive movement of joints, tactile, discrimination below the level of lesion, analgesia and thermoanasthesia on the opposite side of the body).

Investigations

There is considerable increase in CSF proteins. Queekenstedt’s test is positive. Plain X-ray of spine in cases of meningioma will revel an outline of the tumour. Some change in the shape of the pedicles of the vertebral arches or an increase in the interpeduncular distance.

In case of neurofibromas there is erosion of pedicles and enlargement of inter-vertebral foramen through which the tumor emerges.

Myelogram shall show a block at the site of tumor which may be complete or incomplete. Outline of the tumor and its extent is visualized CT scan and MRI are further tests to confirm the diagnosis.

Management

In case of meningioma where growth is very slow, patient generally comes at a late stage. Surgical removal is the treatment of choice. Mortality is low. Complete recovery is expected if tumor has not lasted for more than a year and if sphincter control is intact.

Treatment of neurofibromas is again surgical. Prognosis is good if there is single growth. When neurofibromas are multiple prognosis is not good. Subsequent management shall depend on the degree of paralysis of limbs and how much power returns after the removal of the tumor.

Tumors of spinal cord

Intramedullary tumors

These arise within the substance of the spinal cord most commonly from ependyma of the central canal and are demarcated from the nervous tissue of the cord.

Ependyomas are the commonest of the intramedullary tumors seen commonly in cervico thoracic region and conus medullaris region. Other forms of glioma form the rest of the intramedullary tumors.

These invade the cord and surrounding structures destroying nerve roots, tracts and grey matter. These may occupy multiple segments and because of any definite demarcation are difficult to remove.

Clinically patient presents with unilateral weakness of one limb which soon extends to the other limb. Roots pains are not common. Symptoms shall depend on location of tumor.

On account of different degrees of involvement of sensory tracts, dissociated sensory anesthesia may be seen. Local wasting corresponding to one or more segment is present.

In tumors present in high cervical region, picture may mimic that of syringomyelia. Sphinctre disturbances occur but at a later stage of disease.

Investigations

CSF proteins may be raised only marginally. While in conus medullaris lesions these are markedly raised. Plain X-ray of spine may show thinning of pedicles of several consecutive vertebrae. Because of this the distance between each affected vertebrae is increased.

Myelography may be normal in early stages while in later stage partial obstruction of the dye may be seen. CT scan and MRI usually are normal.

Diagnosis

An intrameduallary tumour has to be differentiated from compression of the cord from outside. Clinically sometimes it becomes difficult.

Queckenstedts test may help in deciding about obstruction. Myelography is an important diagnostic aid. In case of intramedullary tumor it will show fusiform swelling of the cord and a little of oil may pass down at its sides.

Treatment

It is mainly surgical. Ependymomas have been removed successfully while in cases of glioma or haemangioma, surgery is not of much help.

LESIONS OF CAUDA EQUINA AND CONUS MEDULLARIS

Cauda equina may be involved by a tumor, prolapsed intervertebral disc, chronic arachnoiditis, lumbar canal stenosis and spina Bifida. When Cauda equina which mainly consists of nerve roots is involved, symptoms mainly refer to nerve root involvement.

The symptoms shall depend on the site• and extent of involvement of nerve roots. Pain is the presenting feature and is bilateral and usually present in lower lumbar or sacral regions of the spine. It is dull aching pain which is exacerbated by coughing, sneezing or movements of the spine.

Sensory loss depends as to which posterior roots are involved. Involvement of lower sacral roots leads to characteristic saddle shaped anesthesia (Perineum, gluteal region and back of the thigh) and involvement of reflex arc controlling the vesical and rectal sphincters.

This results in urinary retention with over flow and urinary in continence. Rectal sphincter may become atonic and there may be retention of feces. Anal and Bulbo cavernous reflexes are lost. Impotence may occur in men.

Compression of fifth lumbar and upper sacral roots produces sensory loss over the foot and posterior and outer aspects of the legs. There is impairment of all forms of sensations.

Motor symptoms in Cnuda equina lesions consist of lower motor neurone lesion of lower limbs (Flaccid paralysis). Knee and ankle jerks are either diminished or absent. Trophic symptoms may appear over the paralysed limbs.

As compared to Cauda equina, conus medullaris lesion is characterized by early loss of sphincter functions. Anal and Bulbo cavernous reflexes are preserved. The clinical picture may remain unilateral for a long period.

Sensory loss is of dissociated type (sensibility to pain, heat, cold is lost while light touch is preserved). Motor symptoms consist of motor weakness of lower limbs. Knee and ankle jerks are lost while plantar reflex (BABINSKIS sign) is extensor either on one or both sides.

Lesions of both Cauda equina and conus medullaris are diagnosed by myelography. CSF proteins are raised. Treatment is by surgery. Cauda equina lesions carry good prognosis.

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