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In very small infants , the absorptive surface of the peritoneum may be inadequate, warranting the placement of a ventriculoatrial shunt.

CSF may need to be shunted to the pleural space.

X Herniated Disc Syndrome

A Overview

Intervertebral discs contain a soft fibrous center, known as the nucleus pulposus.

The tough fibrous covering is called the anulus fibrosis or disc capsule.

Herniated or “slipped” discs occur when the nucleus pulposus herniates through a rupture or rent in the capsule.

A fragment may extrude completely, in which case it is referred to as a free fragment.

A herniated disc fragment may maintain its continuity with remnants of the nucleus pulposus.

Typically, the disc herniates either underneath or through the posterior longitudinal ligament. It can then come to rest either on the thecal sac, spinal cord, or, more commonly, the nerve roots.

Typically, if the fragment is resting against the nerve root, it produces a recognizable radiculopathic syndrome.

B Cervical disc syndromes

Clinical presentation. Typically, cervical disc herniation presents initially as neck pain, which is presumably secondary to inflammation of the disc capsule and the adjacent posterior longitudinal ligament.

Pain may be located between the scapula, then radiate up into the neck and head.

Radicular signs and symptoms often accompany cervical disc herniation, or they develop during the subacute period.

Symptoms include pain that radiates into the arm, often in a typical distribution.

Cervical disc herniation may be associated with numbness or a dysesthetic pain and weakness as well as loss of reflexes.

The most common disc herniations are the C-6/C-7 disc herniation and the C-5/C-6 disc herniation.

The patient may have cervical muscle spasm.

The pain may be exacerbated by flexion/extension of the neck or lateral rotation as well as by pressing on the vertex of the head.

The disc findings are reviewed in Table 27 -1.

Treatment. Patients are often treated with a conservative regimen of analgesics, nonsteroidal anti - inflammatory drugs, mild muscle relaxants, bed rest, cervical collar, and cervical traction. If conservative therapy is unsuccessful, surgical removal and decompression may be required.

Central and lateral herniation. An anterior approach is used for removal of the disc and

Clinical presentation. Typically, patients have a history of back pain often brought on by trauma, such as lifting or Valsalva's maneuver. Patients often report pain exacerbated by sitting or procedures involving Valsalva's maneuver (e.g., straining or bowel movements).

Physical examination often shows intense lumbosacral spasm. Frequently, a positive “straight leg raising” sign, as well as radicular signs and symptoms, are present. An overview of the physical signs is reviewed in Table 27 -2.

Treatment. As with cervical spine problems, patients are first treated with bed rest, analgesics, antispasmodic agents, and nonsteroidal anti -inflammatory drugs.

If pain does not subside, then patients undergo further study, which can include a CT scan, an MRI scan, or a myelogram (increasingly, MRI is becoming the screening study of choice for disc herniations).

Typically, if the pain is unresponsive to conservative management and bed rest, then the patient will need a discectomy through a posterior approach.

E Lumbar spondylosis

As in the neck, osteoarthritis can produce arthropathy and narrowing of the canal.

Clinical presentation. The patient describes pain that is aching in nature, exacerbated by prolonged standing or walking, and ameliorated by sitting. Most often, the patient reports pain that radiates into the buttocks and down into one or both legs.

Diagnosis. This condition is usually best assessed with plain films and CT scan because it is critical to see the structures of the bones in this particular syndrome. Myelogram may be necessary in some situations to get a better assessment of exactly which nerve roots are being compressed.

Treatment. Conservative therapy, including heat, analgesics, and antispasmodics, may be helpful in some cases. As the disease progresses, surgical decompression by laminectomy may be required.

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TABLE 27-2 Lumbar Disc Herniation Syndrome

Adapted from Freedman AH, Wilkins RH. Neurosurgical Management for the House Officer. Baltimore: Williams & Wilkins; 1984.

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XI Tumors of the Spinal Cord

A Classification

Tumors of the spinal cord are generally classified as being intramedullary, extramedullary, intradural, or extradural. This is based on characteristic myelographic appearances. This classification is still used for both CTand MR-based studies.

B Types

Common tumors of the spinal cord include astrocytomas, ependymomas, schwannomas, neurofibromas, meningiomas, metastases, chordomas, and lipomas.

Astrocytomas. As in the brain, astrocytomas of all grades can occur in the spinal cord. Most frequently, they occur in the cervical and thoracic regions. These tumors may or may not be associated with an intramedullary cyst.

Ependymomas often occur in the cervical spine and are often associated with the syrinx. A second group of ependymomas involves the filum terminale of the lumbosacral region. In general, ependymomas tend to have their peak incidence in the first and second decades of life.

Schwannomas arise from the Schwann's cells, which are associated with the spinal nerve roots. Typically, these present as dumbbell-shaped tumors protruding throughout the neural foramen. They tend to present in the third to sixth decades of life, with radiculopathy that evolves to spinal cord compression. Often, schwannomas may be multiple as part of neurofibromatosis.

Neurofibromas have their peak frequency in the third to fifth decades of life. Their clinical presentation is nearly identical to that of schwannomas and can also be associated with neurofibromatosis.

Meningiomas most typically occur in the thoracic or, less frequently, in the cervical region. They arise in the intradural extramedullary space. As with meningiomas of the brain, they occur predominantly in females.

Metastatic tumors typically occur in the vertebral body, secondary to blood supply to this region. The most frequent primary tumors occur in the lung, breast, or prostate. These tumors tend to occur extradurally and produce extramedullary compression. In contrast, some CNS tumors produce drop metastases, where the primary lesion then spreads to the subarachnoid space in the lumbosacral region. Tumors that have a propensity to do this are medulloblastomas, ependymomas, and pineal tumors that have metastasized throughout the spinal subarachnoid space.

Chordomas originate from remnants of the notochord during embryologic development. Spinal chordomas tend to be in the sacral coccygeal region or in the clival region. These lesions are destructive to bone, and it often is very difficult to get complete resections. Intense radiation treatment is often required after resection.

Lipomas can occur in intradural or extradural locations. Intradural lipomas are usually dorsal to the lumbosacral spine and often are associated with lipomeningocele and tethering of the spinal cord with a lipoma in the filum terminale.

Intramedullary lesions typically present with a gradual evolving myelopathy and often with a partial Brown -

Séquard syndrome. In contrast, extradural lesions often are associated first with a radiculopathy and then with gradual spinal cord compression and myelopathy.

C

Diagnosis is usually established by localizing the level of lesion by neurologic examination and then proceeding with radiographic studies. These studies can include CT or MRI scans with and without gadolinium. MRI is now becoming the study of choice as a relatively quick and noninvasive way to assess the spinal canal as well as the spinal cord nerve roots. In the event that MRI is nondiagnostic, the decision can be made to proceed with standard myelography with or without a postcontrast CT scan.

D Treatment

involves the administration of high-dose steroids to help with spinal cord compression and edema. Surgical intervention is aimed at obtaining tissue diagnosis as well as decompression and stabilization. Often, with incomplete resections of metastatic tumor, radiation therapy is helpful not only in controlling the tumor but also in palliation for pain.

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XII Brachial Plexus Injuries

A Brachial plexopathy

Anatomy. The brachial plexus (Fig. 27 -6) is an exceedingly complex anatomical structure that involves a transition from the cervical roots (C-5/T -1) to the axilla and four main nerves:

Musculocutaneous

Axillary

Median

Ulnar

Clinical presentation. Brachial plexus injuries can occur as a result of blunt, penetrating, or neoplastic injury. Most typically, brachial plexopathy is seen in the setting of trauma where the neck is severely stretched and there is a stretch avulsion injury to the brachial plexus.

Physical examination. Examination of the brachial plexus is complex because it involves not only an evaluation of the cervical cord but also an appreciation of the different motor groups and sensory areas subserved by the different nerves. In general, weakening of the scapula and weakness of the rhomboids are looked for, as is evidence of paralysis or elevation of the ipsilateral diaphragm (injury to the C-4 nerve root or phrenic nerve) or presence of Horner's syndrome.

Evaluation includes extensive electromyography as well as nerve conduction studies. Evaluation of the brachial plexus can involve a myelogram followed by a CT scan with metrizamide or, alternatively, an MRI to evaluate the nerve roots and brachial plexus.

Treatment and prognosis. Nerve root avulsions generally have a very poor prognosis. If there is residual motor and sensory function, then the patient has an excellent chance of regaining function of the nerve root. However, if the nerve root is severed, then the patient may need a cable graft to restore function in these areas.

B

Thoracic outlet syndrome results from occlusion of the subclavian artery or vein. Thoracic outlet syndrome usually results as an aching pain in the axilla or along the forearm that is positionally dependent. If the syndrome is allowed to progress or goes undiagnosed, then weakness can occur, primarily in the intrinsic muscles of the hand. Frequently, a supraclavian bruit is heard on physical examination. Treatment involves resection of an anomalous cervical rib.

FIGURE 27-6 Simplified diagram of the brachial plexus.