Cancer of the Spine

While primary tumors of the vertebrae (e.g., multiple myeloma) are uncommon, metastases to the spine are frequent. The spine is the most common site for skeletal metastases.22 At autopsy, 70% of patients who die from cancer demonstrate vertebral metastases,23 and more than 5% have evidence of metastatic compression of the spinal cord.24 This is usually an extradural anterior mass that involves bone. Intradural extramedullary tumors are usually histologically benign meningiomas or neurofibromas. Gliomas (i.e., ependymomas, astrocytomas, and medulloblastomas) are usually intramedullary, although occasionally they are also found in an extramedullary site. Although the response to treatment is quite different for all of these histologically distant tumors, the neurologic symptoms, signs, and rehabilitation interventions are quite similar.

Injury to the spinal cord and peripheral nerves is a recognized risk of therapeutic radiation that may not become manifest for many months, or even years.25 A transient radiation myelopathy primarily involving sensory neurons may occur in 10 to 15% of patients receiving mantle radiation for Hodgkin's disease.26 This condition is usually associated only with sensory symptoms, such as paresthesias and Lhermitte's sign, and resolves in 1 to 9 months.26 Delayed radiation myelopathy is an irreversible and progressive neurologic condition that may affect motor, sensory, and sphincter functions and has a reported incidence of 1 to 12%.27

Clinical Presentation

By far the most frequent presenting symptom of a tumor of the spine is pain. The pain may be localized, diffuse, or radicular in nature. It is characteristically made worse by activity and by straining. Different from more benign back pain, the pain caused by tumors tends to be persistent, to be present or even worse at night, and is not relieved by rest. Additional symptoms at presentation may be weakness of the legs, difficulty in walking, and urinary sphincteric problems leading to incontinence.

Neurologic deficits may develop insidiously or occur suddenly, depending on the tumor's rate of growth and location, or on the occurrence of a sudden pathologic fracture. Slowly progressive neurologic dysfunction is often seen with tumors of the lower spine that encroach on the cauda equina, whereas tumors of the thoracic spine may cause the sudden collapse of a vertebral body with direct compression of the spinal cord or of its blood supply. Although only half of all tumors of the spine are located in the thoracic region, these cause 70% of all spinal cord compressions that result in paraplegia. Such paraplegia may be neurologically complete, that is, with total paralysis and sensory loss below the level of the lesion. More frequently, however, the neurologic lesion is incomplete, with sensation and motor function preserved to varying degrees, as may be rated by the ASIA Impairment Scale,28 which is a modified version of the Frankel Scale.29,30 Impaired bladder and bowel control at first may present clinically as urinary urgency or hesitancy, but with progressive cord compression, urinary retention or bowel and bladder incontinence may occur.

Treatment

Proper rehabilitation management planning and intervention depend on an accurate diagnosis and staging of the tumor, just as does the medical and surgical management. Most patients with spinal metastases can and should be managed nonsurgically with radiation, chemotherapy, and orthotic stabilization of the spine, since it has been demonstrated that radiation alone provides results that are similar to those of surgery followed by radiation.31 In general, laminectomy with decompression has been found to be of limited use as compared with radiation, since the compressive lesion is usually located anteriorly to the cord, and the surgical procedure itself contributes to spinal instability. However, profound neurologic deficits, especially when occurring rapidly, may warrant surgical decompression, which preferably should be done by an anterior approach followed by surgical stabilization of the spine. Surgical decompression of the spinal cord is not very effective once the patient has become completely paraplegic. Surgical stabilization may often be indicated when gross spinal instability is present, as two of the three “columns” (anterior, middle, and posterior) of the spine have been destroyed by the tumor.32 The extent of surgical stabilization varies, depending on the patient's anticipated life expectancy. Patients with short life expectancy (less than 1 year) benefit most from a relatively simple procedure employing methylmethacrylate, which allows immediate spinal stability and rapid mobilization of the patient, whereas patients with a more favorable prognosis may be better served by vertebrectomy, spinal instrumentation, and bony fusion in conjunction with methylmethacrylate.32

Spinal metastases and myelomatous lesions, even when accompanied by compression fractures and minor or modest spinal instability, can be successfully managed by spinal orthotic support and radiation. Both modalities may significantly decrease pain. Lesions in the cervical spine are most rigidly immobilized by a halo brace (Fig. 71.1) but also may be adequately supported by a SOMI brace (sternal-occipital-mandibular immobilizer) (Fig. 71.2). When such lesions are present in the upper thoracic spine, spinal orthoses may not be necessary, as this part of the spine is stabilized inherently by the rib cage. Lesions in the more mobile lower thoracic and lumbar spine are often associated with severe pain. An adjustable thoracolumbar sacral (TLS) orthosis (Fig. 71.3) with posterior stays may provide sufficient support for less severe lesions, decrease pain, and allow greater mobility. The soft anterior portion of the corset, the apron, should fit snugly over the entire abdomen for optimal support. Larger lesions and postoperative conditions may require fabrication of a custom-molded plastic TLS brace, a two-piece removable orthosis (Fig. 71.4) that firmly grabs the pelvis below and the chest above.

When neurologic loss has occurred, the rehabilitation therapy must be carefully individualized, on the basis of the extent of the neurologic dysfunction, the medical/surgical condition, and the patient's life expectancy. Spinal cord dysfunction with severe or complete paralysis and sensory loss, and perhaps bladder and bowel dysfunction, warrants a comprehensive but relatively short-term rehabilitation program involving as many members of the rehabilitation team as judged appropriate by the physiatrist. The rehabilitation programs should be designed to address each of the many clinical complications and conditions that may be seen in individuals with spinal cord dysfunction of traumatic origin (Table 71.6). Early intervention should include bedside physical and occupational therapy, establishment of bowel and bladder training programs, and the application of nursing principles to prevent complications, such as pressure sores and joint contractures, that increase morbidity, worsen the functional prognosis, and prolong the rehabilitation phase. Proper positioning of the patient in bed and turning at least every 2 hours is of paramount importance in this regard. The patient and family are given emotional support and are educated in the medical aspects of spinal cord dysfunction and management. If the prognosis is poor (i.e., less than 6 months) the patient is instructed early in the ADL skills, which he or she can quickly learn to perform, and provided with the necessary assistive devices, such as a wheelchair, nursing supplies, and personal assistance. As soon as medically appropriate, discharge from the hospital to the home or a nursing facility can be accomplished. When life expectancy is greater and the general criteria for admission to the inpatient rehabilitation service are met, the patient may be transferred there for a more comprehensive and intensive rehabilitation program