Also called a ruptured or slipped disk or a herniated nucleus pulposus, a herniated disk 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 usually occur in adults (mostly men) under age 45.
Herniated disks may result from severe trauma or strain or may be related to intervertebral joint degeneration. In older patients, whose disks have begun to degenerate, minor trauma may cause herniation. About 90% of herniated disks occur in the lumbar and lumbosacral regions, 8% occur in the cervical area, and 1% to 2% occur in the thoracic area.
Patients with a congenitally small lumbar spinal canal or with osteophyte formation along the vertebrae may be more susceptible to nerve root compression with a herniated disk and more likely to have neurologic symptoms.
The overriding symptom of lumbar herniated disk is severe lower 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, and bending intensify the pain, which is commonly accompanied by muscle spasms. A herniated disk may also cause 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 mechanisms that intensify disk pain are diagnostically significant. The following test results support the diagnosis:
❑ The straight-leg-raising test and its variants are perhaps the best tests for diagnosing a herniated disk. For this 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 and 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 Lasegue’s 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 a herniated disk because a marked disk prolapse can be present despite a normal X-ray.
❑ Peripheral vascular status check, including posterior tibial and dorsalis pedis pulses and the skin temperature of extremities, helps rule out ischemic disease, another cause of leg pain or numbness.
❑ Aside from the physical examination and X-rays, myelography, computed tomography scans, and magnetic resonance imaging provide the most specific diagnostic information, showing spinal canal compression by herniated disk material.
Treatment measures are initially conservative and consist of several weeks of bed rest (possibly with pelvic traction), heat applications, an exercise program, and medication. If neurologic impairment progresses rapidly, surgery may be necessary.
Aspirin reduces inflammation and edema at the site of injury; rarely, corticosteroids such as dexamethasone may be prescribed for the same purpose. Muscle relaxants also may be beneficial.
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.
Chemonucleolysis — injection of the enzyme chymopapain into the herniated disk to dissolve the nucleus pulposus — is a possible alternative to laminectomy. Percutaneous automated diskectomy or microdiskectomy can also be used to remove fragments of the nucleus pulposus.
❑ Herniated disk requires supportive care, careful patient teaching, and strong emotional support to help the patient cope with the discomfort and frustration of chronic lower back pain.
❑ If the patient requires myelography, reinforce 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.
❑ Before myelography, question the patient carefully about allergies to iodides, iodine-containing substances, or seafood because such allergies may indicate sensitivity to the test’s radiopaque dye.
❑ After myelography, 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 an 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.
❑ Apply 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.
❑ Remind the patient to cough, deep-breathe, and use an incentive spirometer to prevent pulmonary complications.
❑ Assess for bowel function. Use a fracture bedpan for the patient on complete bed rest.
❑ After laminectomy, microdiskectomy, or spinal fusion, enforce bed rest. If a blood drainage system (Hemovac) 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 (possibly cerebrospinal fluid leakage) or excessive drainage immediately. Observe the neurovascular status of the legs (color, motion, temperature, and sensation).
❑ Monitor vital signs, and check for bowel sounds and abdominal distention. Use the logrolling technique to turn the patient.
Clinical tip Administer analgesics, especially 30 minutes before initial attempts at sitting or walking. Help the patient 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 necessary.
❑ 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 him to maintain proper weight to prevent lordosis caused by obesity.
❑ Before chemonucleolysis, ask the patient about allergies to meat tenderizers (chymopapain is a similar substance). Such an allergy contraindicates the use of this enzyme, which can produce severe anaphylaxis in a sensitive patient. Enforce bed rest. Administer analgesics and apply heat, as needed. Assist with special exercises, and tell 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.
Review other book chapters online related to Herniated disc:
Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
|
More About This Book:
Title: Handbook of Diseases Authors: Springhouse Publisher: Lippincott Williams & Wilkins Copyright: 2003 ISBN: 1-58255-266-5 
|
|
What do you think about the features of this website? Take our user survey and have your say:
Next articles:
Tools & Services:
Medical Articles:
Search Specialists by State and City
By using this site you agree to our Terms of Use. Information provided on this site is for informational purposes only; it is not intended as a substitute for advice from your own medical team. The information on this site is not to be used for diagnosing or treating any health concerns you may have - please contact your physician or health care professional for all your medical needs. Please see our Terms of Use.
Copyright © 2009 Health Grades Inc. All rights reserved.
