Herniated disk, also called ruptured or slipped disk and herniated nucleus pulposus, occurs when all or part of the nucleus pulposus — the soft, gelatinous, central portion of an intervertebral disk — is forced through the disk’s weakened or torn outer ring (anulus fibrosus). When this happens, the extruded disk may impinge on spinal nerve roots as they exit from the spinal canal or on the spinal cord itself, resulting in back pain and other signs of nerve root irritation.
Herniated disks may result from severe trauma or strain or may be related to intervertebral joint degeneration. Although usually occurring in adults (mostly men) less than 45 years old, elderly people are also at risk because minor trauma may cause herniation in disks that have begun to deteriorate due to age. Ninety percent of herniation occurs in the lumbar and lumbosacral regions of the spine; 8% in the cervical region; and 1% to 2% in the thoracic region. Patients with a congenitally small lumbar spinal canal or with osteophyte formation on the vertebrae may be more susceptible to nerve root compression by a herniated disk and more likely to have neurologic symptoms.
The overriding symptom of lumbar herniated disk is severe low-back pain that radiates to the buttocks, legs, and feet, usually unilaterally. When herniation follows trauma, the pain may begin suddenly, subside in a few days, and then recur at shorter intervals and with progressive intensity. Sciatic pain follows, beginning as a dull pain in the buttocks. Valsalva’s maneuver, coughing, sneezing, or bending intensifies the pain, which is commonly accompanied by muscle spasms. Herniated disk may also cause paresthesias or hyperthesias, as well as sensory and motor loss in the area innervated by the compressed spinal nerve root and, in later stages, weakness and atrophy of leg muscles.
Obtaining a careful patient history is vital because the events that intensify disk pain are diagnostically significant. The straight-leg–raising test and its variants are perhaps the best tests for herniated disk, but may still be negative.
For the straight-leg–raising test, the patient lies in a supine position while the examiner places one hand on the patient’s ilium, to stabilize the pelvis, and the other hand under the ankle, then slowly raises the patient’s leg. The test is positive only if the patient complains of posterior leg (sciatic) pain, not back pain. In Lasègue test, the patient lies flat while the thigh and knee are flexed to a 90-degree angle. Resistance and pain as well as loss of ankle or knee-jerk reflex indicate spinal root compression.
X-rays of the spine are essential to rule out other abnormalities but may not diagnose herniated disk because marked disk prolapse can be present despite a normal X-ray. A thorough check of the patient’s peripheral vascular status — including posterior tibial and dorsalis pedis pulses and skin temperature of extremities — helps rule out ischemic disease, another cause of leg pain or numbness. After physical examination and X-rays, myelography, computed tomography scans, and magnetic resonance imaging (MRI) provide the most specific diagnostic information, showing spinal canal compression by herniated disk material. MRI is the method of choice to confirm the diagnosis and determine the exact level of herniation. A myelogram can define the size and location of disk herniation. An electromyogram can determine the exact nerve root involved. A nerve conduction velocity test may also be performed.
Unless neurologic impairment progresses rapidly, treatment is initially conservative and consists of several weeks of bed rest (possibly with pelvic traction), administration of nonsteroidal anti-inflammatory drugs, heat applications, and an exercise program. Epidural corticosteroids, short-term oral corticosteroids, nerve root blocks, or physical therapy may be used to decrease pain. Muscle relaxants, such as diazepam, methocarbamol, or cyclobenzaprine, may relieve associated muscle spasms.
A herniated disk that fails to respond to conservative treatment may necessitate surgery. The most common procedure, laminectomy, involves excision of a portion of the lamina and removal of the protruding disk. If laminectomy doesn’t alleviate pain and disability, a spinal fusion may be necessary to overcome segmental instability. Laminectomy and spinal fusion are sometimes performed concurrently to stabilize the spine. Microdiskectomy can also be used to remove fragments of nucleus pulposus.
Injection of the enzyme chymopapain into the herniated disk produces a loss of water and proteoglycans from the disk, thereby reducing both the disk’s size and the pressure in the nerve root.
Herniated disk requires supportive care, careful patient teaching, and strong emotional support to help the patient cope with the discomfort and frustration of chronic low back pain.
❑ If the patient requires myelography, question him carefully about allergies to iodides, iodine-containing substances, or seafood because such allergies may indicate sensitivity to the test’s radiopaque dye. Reinforce previous explanations of the need for this test, and tell the patient to expect some pain. Assure him that he’ll receive a sedative before the test, if needed, to keep him as calm and comfortable as possible. After the test, urge the patient to remain in bed with his head elevated (especially if metrizamide was used) and to drink plenty of fluids. Monitor intake and output. Watch for seizures and allergic reaction.
❑ During conservative treatment, watch for any deterioration in neurologic status (especially during the first 24 hours after admission), which may indicate an urgent need for surgery. Use antiembolism stockings as prescribed, and encourage the patient to move his legs, as allowed. Provide high-topped sneakers to prevent footdrop. Work closely with the physical therapy department to ensure a consistent regimen of leg- and back-strengthening exercises. Give plenty of fluids to prevent renal stasis, and remind the patient to cough, deep breathe, and use blow bottles or an incentive spirometer to preclude pulmonary complications. Provide good skin care. Assess for bowel and bladder functions. Use a fracture bedpan for the patient on complete bed rest.
❑ After laminectomy, microdiskectomy, or spinal fusion, enforce bed rest, as ordered. If a blood drainage system (Hemovac or Jackson Pratt drain) is in use, check the tubing frequently for kinks and a secure vacuum. Empty the Hemovac at the end of each shift, and record the amount and color of drainage. Report colorless moisture on dressings (possible cerebrospinal fluid leakage) or excessive drainage immediately. Observe neurovascular status of the legs (color, motion, temperature, and sensation).
❑ Monitor vital signs and check for bowel sounds and abdominal distention. Use logrolling technique to turn the patient. Administer analgesics as ordered, especially 30 minutes before initial attempts at sitting or walking. Give the patient assistance during his first attempt to walk. Provide a straight-backed chair for limited sitting.
❑ Teach the patient who has undergone spinal fusion how to wear a brace. Assist with straight-leg–raising and toe-pointing exercises, as ordered. Before discharge, teach proper body mechanics — bending at the knees and hips (never at the waist), standing straight, and carrying objects close to the body. Advise the patient to lie down when tired and to sleep on his side (never on his abdomen) on an extra-firm mattress or a bed board. Urge maintenance of proper weight to prevent lordosis caused by obesity.
❑ After chemonucleolysis, enforce bed rest as ordered. Administer analgesics and apply heat, as needed. Urge the patient to cough and deep breathe. Assist with physical therapy as necessary and advise the patient to continue these exercises after discharge.
❑ Tell the patient who must receive a muscle relaxant of possible adverse effects, especially drowsiness. Warn him to avoid activities that require alertness until he has built up a tolerance to the drug’s sedative effects.
❑ Provide emotional support. Try to cheer the patient up during periods of frustration and depression. Assure him of his progress, and offer encouragement.
Review other book chapters online related to Herniated disc:
Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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More About This Book:
Title: Professional Guide to Diseases (Eighth Edition) Authors: Springhouse Publisher: Lippincott Williams & Wilkins Copyright: 2005 ISBN: 1-58255-370-X 
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