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Mechanical and Other Lesions of the Spine, Nerve Roots, and Spinal Cord
Disorders of the spine, nerve roots, and spinal cord are common and frequently disabling. At any one time, 1% of the U.S. population is chronically disabled by lower back pain and another 1% temporarily disabled. Lower back pain is the number one cause of years lived with disability in the United States, and neck pain is the number six cause. Low back and neck pain also are the leading causes of disability in most countries and for most age groups and have increased over the past 25 years. Although the natural prognosis for acute and even chronic spine and limb pain is good, expensive, and sometimes hazardous, imaging studies and treatments are often prescribed.
Pathobiology
The 7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar vertebrae, the sacrum, and the coccyx comprise the spine ( Fig. 369-1 ). Each vertebra has an anterior cylinder-shaped body, which is flattened posteriorly and held together by intervertebral discs, as well as by anterior and posterior longitudinal ligaments ( Fig. 369-2A and B ). Each disc consists of an outer annulus fibrosus, which receives some blood supply, and an inner, softer nucleus pulposus, which is avascular. The vertebral arch is composed of two short, round, rodlike bones called pedicles, which project backward from the dorsolateral surface of a vertebral body. Each pedicle meets a broad lamina. At one level, two laminae are angled posteriorly and medially to meet in the midline behind the vertebral (or spinal) foramen, where they fuse and form the posteriorly projecting spinous process. The ligamenta flava connect vertically to adjacent laminae. At the junctions of the pedicles and laminae, superior and inferior articular processes articulate with similar processes from above and below. These so-called zygapophyseal joints are true synovium-covered joints that help to protect the spine while permitting a limited amount of movement. The overlapping facet joints and multiple sets of longitudinal ligaments give the spine stability during its ranges of motion and prevent excess motion. The posterolaterally placed intervertebral or neural foramina allow the exit of spinal nerves.
The spinal cord has 31 spinal segments, with one more cervical cord segment (8) than vertebra. Each segment gives rise to a bilateral pair of spinal nerves. Spinal nerves C1 to C7 exit the canal above their corresponding vertebral bodies, whereas the C8 nerve exits below the C7 vertebra. Spinal nerves in the thoracic and lumbar spine exit below the vertebra with the same number. Spinal cord segments lie progressively superior to the vertebrae, so that the end of the spinal cord and conus medullaris is at about the L1 vertebral level in adults. Below this level, the spinal nerves travel in a bundle as the cauda equina within the subarachnoid space before exiting through their respective foramina. The spinal cord is wider in the cervical and lumbar cord segments because of the increased number of motor and sensory neurons supplying the upper and lower extremities.
Spinal nerves are formed by joining of the anterior (or ventral) and posterior (or dorsal) spinal nerve roots, which directly enter and exit the spinal cord ( Fig. 369-2B ). The anterior or ventral root is derived from axons of the anterior horn cells and lateral columns. The posterior or dorsal root mostly derives axons from the dorsal root ganglion. The sensory root is twice as thick as the motor root. The spinal nerves exit and enter the spinal canal through the intervertebral or neural foramina formed by the upper and lower pedicles, the vertebral body, and the laminae ( Fig. 369-2A ).
Clinical Manifestations
Most spine disorders are related to spondylosis, which results from wear and tear that takes place in the vertebrae, intervertebral discs, facets, and other true joints of the spine, associated ligaments, and secondarily the paraspinal and other muscles. Pain-sensitive structures in the spine include the periosteum of the bony spine (vertebrae); the dura, facet, and other true joints; the annulus fibrosus (but not the nucleus pulposus); blood vessels; ligaments; and paraspinal muscles.
The most frequent complaint related to spondylosis is axial spine pain affecting the low back more than the neck and more than the midback. With compression or irritation of the spinal nerves, patients can develop tingling, prickling, or burning sensations (termed paresthesias if they occur spontaneously or dysesthesias if they are provoked by stimulation); pain; loss of sensation; weakness; and sometimes autonomic dysfunction (most commonly difficulty with bowel or bladder control).
When it affects a myotome (the group of muscles served by motor neurons of a single spinal cord segment), the motor deficit associated with a spinal root disorder is of the lower motor neuron type. Typical findings are weakness, hypotonia, depressed or absent reflexes, fasciculations, and, if the syndrome has persisted for at least several weeks, muscle atrophy ( Table 369-1 and Table 369-2 ). Sensation at the spinal nerve level is diminished or absent for all modalities in a characteristic dermatomal pattern ( Fig. 369-3 ). Sensation below and above the affected root is intact.
TABLE 369-1
SYMPTOMS AND SIGNS ASSOCIATED WITH SPONDYLOTIC CERVICAL AND HIGH THORACIC RADICULOPATHY
Adapted from Spine Disorders: Medical and Surgical Management by JD Bartleson and HG Deen; Cambridge University Press, 2009. Copyrighted and used with permission of Mayo Foundation for Medical Education and Research.
| USUAL LOCATION OF: | ||||
|---|---|---|---|---|
| DISC LEVEL/ROOT | PAIN | SENSORY ABNORMALITIES | WEAKNESS | AFFECTED REFLEX |
| C3-4/C4 | Neck | Suprascapular, supraclavicular, and top of shoulder | Usually none | None |
| C4-5/C5 | Neck, scapula, shoulder, anterior arm | Lateral arm and forearm | Shoulder abduction and elbow flexion | Biceps, brachioradialis |
| C5-6/C6 | Neck, scapula, shoulder, lateral arm, and forearm | Anterolateral arm, forearm, hand, thumb, and forefinger | Shoulder abduction, elbow flexion, and forearm pronation | Biceps, brachioradialis |
| C6-7/C7 | Neck, shoulder, lateral arm, medial scapula, extensor surface of forearm | Dorsolateral forearm and hand, forefinger, and long finger | Extension of elbow, wrist, and fingers | Triceps |
| C7-T1/C8 | Neck; medial scapula, arm, and forearm | Medial forearm and hand, ring, and little fingers | Finger abduction, adduction, and flexion | None or finger flexor |
| T1-2/T1 | Anterior chest, medial arm, and forearm | Medial arm and forearm | Finger abduction, adduction, and flexion | None or finger flexor |
TABLE 369-2
SYMPTOMS AND SIGNS ASSOCIATED WITH SPONDYLOTIC LUMBOSACRAL RADICULOPATHIES
| USUAL LOCATION OF: | ||||
|---|---|---|---|---|
| DISC LEVEL/ROOT | PAIN | WEAKNESS | AFFECTED REFLEXES | SENSORY ABNORMALITIES |
| L1-2/L1 | Inguinal | None | Cremasteric | Inguinal |
| L2-3/L2 | Inguinal and anterior thigh | Hip flexion, hip adduction, some knee extension | Cremasteric, thigh adductor | Proximal anterior thigh |
| L2-3/L3 | Anterior thigh and knee | Knee extension, hip flexion, hip adduction | Knee, thigh adductor | Anterior and anteromedial thigh including knee |
| L3-4/L4 | Anterior thigh, anteromedial leg | Knee extension, hip flexion, hip adduction | Knee | Anterior knee and medial leg |
| L4-5/L5 | Posterolateral thigh, lateral leg, medial foot | Foot dorsiflexion, inversion and eversion, knee flexion, hip abduction, toe extension and flexion | Internal hamstring | Lateral leg, dorsal foot, and great toe |
| L5-S1/S1 | Posterior thigh and leg, heel, and lateral foot | Foot plantar flexion, toe flexion, knee flexion, hip extension | Ankle, external hamstring | Posterolateral leg and lateral foot, heel |
| L5-S1/S2 | Buttock | Foot plantar flexion, hip extension | Anal reflex, ankle | Posterior leg and thigh, medial buttock |
Conversely, disorders of the spinal cord produce a “level” below which sensation is abnormal and motor deficits are of the upper motor neuron type, with weakness without atrophy (unless caused by disuse), hypertonia, and increased reflexes. At the level of a spinal cord lesion, the motor deficits can be of the lower motor neuron type owing to injury to anterior horn cells or nerve roots; but below this level, an upper motor neuron syndrome will predominate. As with strokes ( Chapter 375 ) and other central nervous system (CNS) insults, the full upper motor neuron syndrome of spasticity and hyperreflexia may be absent in the acute phase of spinal cord injury.
Diagnosis
Knowledge of the usual patterns of the sensory, motor, and reflex innervation of the spinal nerves greatly aids in diagnosis of the patient with possible radiculopathy. The history of sensory loss or motor weakness may be more important than findings on the physical examination. The patient should be asked about, and the neurologic examination focus on, sensory, motor, and reflex functions. Careful side-to-side comparisons can help detect subtle deficits. All muscles receive innervation from more than one spinal nerve and all nerve roots innervate multiple muscles, so individual muscles are rarely profoundly weak when a single root is affected. Give-way weakness, when a patient does not give a full effort, can be due to pain, lack of understanding, the patient trying to help the provider, conversion disorder, and malingering. In this setting it may be best to interpret strength as being at least as good as when it gave way, but the presence or absence of some weakness cannot be known. Overlap of sensory dermatomes explains why sharp demarcations and complete sensory loss rarely occur. All sensory loss is subjective, thereby making the sensory examination less reliable. Typical symptoms and signs associated with cervical and lumbosacral radiculopathies are shown in Tables 369-1 and 369-2 .
Disorders of the Spine
Neck and Low Back Pain
Definition
Most neck and low back pain is mechanical and attributable to the structural elements of the spine. Pain referred to the spine can arise from internal structures in the neck, upper chest, abdomen, or pelvis. Pain of spinal origin may be referred to the upper or lower extremity or the torso. In the lower limbs, conditions affecting the upper lumbar spine tend to refer pain to the groin and/or anterior thigh (from the hip to the knee). Conditions affecting the lumbar spine tend to cause referred pain in the buttock, posterior thigh, leg (from the knee to the ankle), or foot. Referred pain can be unilateral or bilateral. Pain that follows a dermatomal distribution is likely to be due to nerve root pathology.
Epidemiology
Low back pain is more common and more disabling than neck pain. The thoracic spine, possibly because of rib attachments and limited range of motion, is a less common location for spine pain. An exception to this rule is the condition of diffuse idiopathic skeletal hyperostosis ( Chapter 252 ), which is a noninflammatory, age-related condition of unknown etiology, characterized by ossification of paravertebral ligaments and peripheral entheses. It is more common in men and increases with age. Pain in the thoracic spine region occurs in up to 80% of patients with diffuse idiopathic skeletal hyperostosis.
In the general population, the incidence of self-reported neck pain is 213 per 1000; the 12-month prevalence of any neck pain is typically between 15 and 50%, and pain severe enough to limit activity is between 1.7 and 11.5%. The prevalence is higher in women. Risk factors for neck pain include heredity, poor psychological health, occupations such as dentistry, and tobacco use. The presence of disc degeneration does not correlate with the incidence of neck pain.
More than 70% of people will experience lower back pain significant enough to inhibit their participation in daily activities at some time in their life. The highest prevalence is in the 45- to 64-year age group, without a gender difference. Tobacco use is an associated risk factor. Physical work–related factors (e.g., heavy lifting, prolonged sitting, repetitive twisting) increase risk. Prospective studies show that psychosocial issues such as work monotony, job dissatisfaction, and depression also are major predisposing factors for chronic lower back pain.
Pathobiology
Neck and lower back pain can occur with or without radicular pain. In the low back, radicular lower limb pain usually affects the L5 or S1 nerve root. In the cervical spine, the C7 nerve root is most affected. Radicular upper or lower limb pain is usually caused by compression and irritation of the spinal nerve, typically by a protruding disc or osteoarthritic change. The precise cause of axial neck and lower back pain is often difficult to determine. The degenerative process of spondylosis, including facet joint pathology, is thought to be responsible for both acute and chronic axial spine pain, whereas the intervertebral disc is thought to account for a minority of symptoms. Intervertebral disc degeneration has a genetic predisposition with heritability estimates in the range of 35 to 75%.
Spondylosis is accompanied by disc degeneration, the formation of osteophytes, ligamentous hypertrophy, facet joint arthropathy, and vertebral subluxation (spondylolisthesis) of one vertebral body forward (anterolisthesis) or backward (retrolisthesis) on its mate below. The vast majority of people develop spondylosis, which includes disc desiccation and loss of elasticity of the annulus fibrosus. Congenital or acquired fractures of the pars interarticularis on both sides of one lumbar spinal level, termed spondylolysis, promote the development of spondylolisthesis. Spondylolisthesis is graded by the amount of maximal shift in quartiles from 0 being normal to 5 being total dissociation of the vertebral body with an adjacent vertebra. Stability of spondylolisthesis is estimated by plain radiographs of the spine with the patient in flexion and extension.
Whiplash, an acute flexion or extension injury (or both) of the cervical spine, is common, especially after motor vehicle accidents. The acute whiplash syndrome is thought to be a result of mechanical irritation of pain-sensitive mostly musculoskeletal structures in the cervical spine, typically without spinal cord or spinal nerve injury. More severe trauma can cause fracture and vertebral instability, which often require urgent surgical intervention.
Clinical Manifestations
Acute neck pain and lower back pain are commonly limited to the axial region, although radicular signs and symptoms can occur in the presence of nerve root irritation. The most common radicular pain occurs in the distribution of a dermatome. Other radicular signs and symptoms can include dysesthesias or sensory loss in the affected dermatome, decreased strength in muscles of the affected myotome, and one or more decreased reflexes. Cranial nerve findings, diffuse weakness throughout a limb or in more than one limb, hemisensory symptoms, autonomic symptoms, and diffuse increase in reflexes are not typical manifestations of spine disease in the absence of spinal cord compression; these signs and symptoms should prompt evaluation for other conditions that affect the brain, brain stem, or spinal cord. Bowel and bladder symptoms should prompt urgent evaluation for cauda equina compression or a myelopathy.
Acute spine problems can also cause referred pain at sites other than their anatomic source. More often, the term referred pain denotes the situation in which other structures, usually internal organs, refer pain to the spine or limbs. Areas of referred pain usually share the same embryologic origin and the same sensory pathways. Differentiation of referred pain from localized spine pain is aided by the history and examination. Mechanical pain is often exacerbated by spinal movement, whereas referred pain tends to be independent of such activities. Sciatica, which is defined as pain in the distribution of the sciatic nerve, often includes pain in the back as well as the buttock, posterior thigh, leg, and foot. Although sciatica can be caused by a lesion anywhere along the course of the sciatic nerve, it is most commonly caused by injury to one of the exiting spinal nerves that contribute to the sciatic nerve (L4-S2).
Diagnosis
A structured approach can improve outcomes while avoiding unnecessary diagnostic tests and ineffective therapies ( Fig. 369-4 ).
History and Clinical Examination
The history and physical examination are essential for the initial evaluation and triage of patients with neck and lower back pain, with or without possible radicular upper or lower limb pain. “Red flags” help identify patients who may have a serious underlying cause for their spinal pain (e.g., fracture, infection, hemorrhage, tumor, serious neurologic disease) and generally warrant very prompt diagnostic evaluation and possibly earlier medical or surgical intervention ( Table 369-3 ). Red flags for neck or upper limb pain are similar to those for lower back pain with the addition of conditions unique to the cervical spine (rheumatoid arthritis, spondyloarthropathy, and Down syndrome); neck pain associated with chest pain, diaphoresis, or dyspnea, which can occur with myocardial ischemia ( Chapter 57 ); and signs or symptoms of myelopathy. However, most patients do not present with red flags, and guidelines for patients without red flags usually recommend a wait-and-see approach for at least 4 to 6 weeks after the onset of neck or lower back pain.
TABLE 369-3
“RED FLAGS” IN THE EVALUATION OF SPINE PAIN
| History of trauma Unexplained weight loss Unexplained fever Immunosuppression History of cancer History of recent surgery Systemic disorder Intravenous drug use Osteoporosis Prolonged use of corticosteroids Age <20 or >50 years Significant or progressive neurologic deficit Myelopathy Possible cauda equina syndrome Duration > 6-12 weeks Uncontrollable pain |
On clinical examination, inspection should assess for evidence of trauma, muscle wasting, fasciculations, erythema, rashes, and scars. Palpation should look for areas of point tenderness, muscle spasm, and masses. If light percussion of the spinous process evokes significant pain, a focal lesion, such as fracture, tumor ( Chapter 175 ), or infection ( Chapter 382 ), should be considered. Active and passive range of motion for flexion, extension, rotation, and side-to-side bending should be tested.
Many provocative tests have been described for the evaluation of spine and limb pain, but few have undergone formal evaluation of their diagnostic accuracy. For neck and upper limb pain, an increase in symptoms with contralateral rotation of the neck and extension of the arm and fingers ( Video 369-1 ) suggests cervical root involvement, as does the Spurling maneuver, in which the patient’s head is bent backward and flexed (bent) laterally to the symptomatic side. Provocation of radicular pain or paresthesias with or without downward pressure on the top of the patient’s head suggests cervical nerve root impingement or irritation ( Video 369-2 ). Diagnostic tests also can reduce symptoms. In the cervical distraction test, the examiner’s hands are placed under the jaw and occiput. Gentle upward pulling of the head can temporarily reduce or alleviate the symptoms of cervical spinal nerve impingement ( Video 369-3 ).
Provocative tests that can be helpful in the patient with low back and lower limb pain include straight leg raising performed with the patient supine. The examiner flexes the thigh at the hip while the leg is held in extension at the knee. The test is positive if pain along the course of the sciatic nerve is provoked. Further increase in pain with foot dorsiflexion provides additional evidence of lumbosacral nerve root impingement.
Straight leg raise ( Video 369-4 ) has sensitivity of 0.85 to 0.91 but a specificity of only 0.26 to 0.52 for the diagnosis of sciatica due to a herniated disc. A positive crossed straight leg raise test ( Video 369-5 ), which has a lower sensitivity of 0.23 to 0.34 but a much higher specificity of 0.86 to 0.90, is often positive in the presence of a disc extrusion. Positive seated straight leg raising when the knee is fully extended is about as useful as a positive test at 65 degrees elevation when the patient is supine ( Video 369-6 ). In reverse straight leg raising, the examiner maximally flexes the knee while the patient is prone; provocation of same-sided pain, usually in the anterior thigh, is highly suggestive of impingement of the L2, L3, or L4 nerve roots, which contribute to the femoral nerve and are stretched by this maneuver.
Ancillary Testing
For acute and subacute neck and lower back pain, observation and conservative treatment are recommended if no red flags are present. If the patient’s symptoms are unchanged after 4 to 6 weeks, then further investigation can be considered. Magnetic resonance imaging (MRI) is the diagnostic test of choice for patients with neck and lower back pain, especially if they have radicular pain or evidence of myelopathy. MRI is recommended only in patients who have major or progressive neurologic deficits, in whom a serious underlying condition is suspected, or in whom surgery or epidural corticosteroid injections are being considered. Even in patients age 65 years and older, the value of early diagnostic imaging in patients without radiculopathy is uncertain. However, MRI abnormalities are common in asymptomatic patients, so MRI has a very high false-positive rate when imaging the cervical or lumbar spine. Frequent asymptomatic findings include loss of disc signal intensity, disc protrusion, narrowing of the disc space, facet arthropathy, and central or foraminal stenosis.
The need to correlate the patient’s presentation with their imaging findings cannot be overemphasized. More than half of asymptomatic patients will have more than one potentially symptomatic cervical or lumbar finding on MRI. This number approaches 100% with age older than 50 to 60 years. Modic changes in the vertebrae, spondylolisthesis, and lumbar disc extrusion are more strongly associated with low back pain than is disc degeneration without end plate changes. Discography is an invasive procedure that can be of some help in diagnosing lumbar internal disc disruption, which is a condition that may cause low back pain but for which there is no known effective treatment. Discography is not recommended in the cervical spine.
Computed tomography (CT), usually with the instillation of contrast (CT myelography), is not as accurate as MRI but is the test of choice for patients who are intolerant of or unable to undergo MRI. CT myelography can be complementary to MRI, and one imaging study may be positive when the other is not. Otherwise, with few exceptions, MRI is the test of choice given its superiority in evaluating soft tissue structures and its lack of radiation exposure.
For stress fracture ( Chapter 225 ), plain CT and single-photon emission computed tomography (SPECT) are more sensitive than MRI. CT can also be used to evaluate scoliosis, bone graft integrity, implanted instrumentation, and union of surgical fusion.
Plain radiography is of some use for judging the presence of spondylosis, vertebral enumeration, congenital abnormalities, normal cervical and lumbar lordosis and alignment, and absence of gross fracture and spinal instability. For patients in whom only a benign lumbar compression fracture is suspected, plain radiography may suffice if the results are normal and no other abnormalities are present.
Electrodiagnostic testing is not usually helpful in axial spine pain without neurologic symptoms. It can, however, be useful in documenting the presence and activity of radiculopathy and in diagnosing other conditions (e.g., brachial plexus neuritis, carpal tunnel syndrome, and sciatic neuropathy). Furthermore, it is a lagging indicator and may not become abnormal until 4 weeks have elapsed from the onset of nerve injury.
Differential Diagnosis
The differential diagnosis of neck pain ( Table 369-4 ) and lower back pain ( Fig. 369-5 ) is very broad. Acute mechanical neck pain is most often caused by neck muscle strain, a herniated nucleus pulposus, or whiplash. Up to 97% of cases of low back pain are due to mechanical causes or are idiopathic. For neck pain of gradual onset, osteoarthritis and cervical spinal stenosis are leading causes. For low back pain, muscle strain and a herniated nucleus pulposus are possible acute causes, whereas insidious causes include osteoarthritis, lumbar spinal stenosis, spondylolisthesis, sacroiliitis ( Chapter 244 ), and scoliosis ( Fig. 369-5 ). The presence of red flags will help identify serious and nonmechanical causes of neck and low back pain.
TABLE 369-4
MAJOR CAUSES OF NECK PAIN
| SPONDYLOTIC DEGENERATIVE DISEASE |
| Joints: facet, uncovertebral Discs: herniation, degeneration Bone: fracture, hypertrophic spurring Muscle: acute strain, chronic pain |
| CONGENITAL/ACQUIRED DEFORMITY |
| Klippel Feil syndrome (congenital fusion of two or more cervical vertebrae) Iatrogenic fusion Craniocervical subluxation Cervical spinal stenosis |
| RHEUMATOLOGIC |
| Rheumatoid arthritis ( Chapter 243 ) Ankylosing spondylitis ( Chapter 244 ) Other spondyloarthropathy ( Chapter 244 ) Polymyalgia rheumatica ( Chapter 250 ) Fibromyalgia ( Chapter 253 ) |
| TRAUMA ( Chapter 368 ) |
| Sprain (e.g., from whiplash) Fracture |
| TUMOR ( Chapters 175 and 176 ) |
| Bony spine Spinal cord Head and neck |
| INFECTION |
| Osteomyelitis ( Chapter 251 ) Disc space infection Epidural abscess ( Chapter 382 ) Meninges Spinal cord |
| NEUROGENIC ( Chapter 366 ) |
| Spinal nerves Spinal cord Meninges |
| REFERRED FROM VISCERA |
| Lung tumor, especially at the apex (Pancoast tumor; Chapter 177 ) Upper esophagus ( Chapter 124 ) Carotid or vertebral artery dissection ( Chapter 376 ) Myocardial ischemia ( Chapters 56 to 58 ) Thyroid ( Chapter 207 ), throat ( Chapter 397 ), and laryngeal disease ( Chapter 397 ) |
| PSYCHOGENIC ( Chapter 362 ) |
| With or without an additional source of pain Malingering |
Abdominal and pelvic structures can refer pain to the low back. Abdominal aortic aneurysms ( Chapter 63 ) can present with mid- or low back pain that may radiate to the hips or anterior thighs. Dissection of the thoracic aorta ( Chapter 63 ) can cause sudden severe pain in the front and back of the chest, including the spine. Cholecystitis ( Chapter 141 ) can cause pain in the midthoracic area. Pancreatic disease ( Chapter 130 ) can cause pain in the L1 region. Diverticulitis ( Chapter 128 ) can cause lower abdominal and diffuse low back pain. Genitourinary disorders ( Chapter 111 ) can cause colicky pain referred to the flank and costovertebral angle. Bladder disorders can occasionally refer pain to the sacral area, as can prostate conditions ( Chapter 114 ). Pelvic disorders in women that can cause referred low back pain include endometriosis ( Chapter 218 ), ectopic pregnancy, and pelvic inflammatory disease ( Chapters 275 and 294 ). Most of these disorders have additional signs and symptoms to aid in the diagnosis.
Myocardial ischemia ( Chapters 56 to 58 ) can be associated with anterior neck pain, although less commonly than with left arm or jaw pain. Arterial dissections ( Chapter 63 ) are more commonly associated with neck pain. For example, about 25% of patients with carotid dissections ( Chapter 376 ) complain of anterolateral neck pain, and about 50% of patients with vertebral dissections have posterior neck pain. Patients with arterial dissections can have signs and symptoms of stroke ( Chapter 376 ). Disorders of the esophagus ( Chapter 124 ) and mass lesions of the neck and throat ( Chapters 176 and 397 ) can present with neck pain.
Acute radicular pain can precede the rash in herpes zoster ( Chapter 346 ). Sickle cell anemia can cause severe pain in almost any location, including the spine ( Chapter 149 ). Infections of the disc ( Chapter 382 ) can cause severe back pain worsened by movement. Arachnoiditis ( Chapter 381 ), an inflammatory process of the arachnoid membrane, can cause chronic back and radicular pain, often after spine surgery or the introduction of a foreign substance into the intrathecal space. Twenty to 50% of patients with depression ( Chapter 362 ) will complain of back pain that is often diffuse and described in emotionally laden terms. Complaints of low back pain are also common in malingering patients.
Treatment
Patients with neck or lower back pain, with or without limb pain, should try to continue routine activities insofar as possible.
Medications
Medication options include nonsteroidal anti-inflammatory drugs (NSAIDs) (e.g., ibuprofen 600 mg three times daily for up to a few weeks) and skeletal muscle relaxants (e.g., cyclobenzaprine 5 to 10 mg three times daily, tizanidine 2 to 6 mg three times daily, or carisoprodol 250 to 350 mg three times daily for up to a few weeks) Muscle relaxants are of short-term help for acute pain with muscle spasm, but can cause sedation. Duloxetine (60 mg once daily) can be helpful for chronic low back pain. Acetaminophen is not helpful for low back pain and is of uncertain benefit for neck pain. Systemic corticosteroids do not seem to be effective. Opioid analgesics are not effective , and should not be prescribed for acute neck or low back pain or for chronic low back pain.
Nonsurgical Interventions
No data support corticosteroid injections into facet joints for axial neck or lower back pain, although transforaminal and interlaminar epidural corticosteroid injections are indicated for radicular pain. Temporary pain relief with medial branch nerve blocks can help determine which facet joints are responsible for axial neck and lower back pain. If medial branch blocks are helpful, radiofrequency ablation of the identified nerves can provide months of pain relief, especially for chronic neck pain.
Heat, massage, physical therapy, acupuncture, and spinal manipulation are helpful for acute and subacute lower back and possibly for axial neck pain, but bed rest is not recommended for acute neck or low back pain. For chronic neck pain, yoga therapy provides modest to significant pain relief. Cervical collars and traction are not of established benefit. Chiropractic or osteopathic manipulation is more helpful for low back pain than for neck pain and better for acute than chronic pain, but its benefit is small.
Helpful therapies for chronic low back pain include tai chi, mindfulness-based stress reduction, and yoga. Psychological and physical therapies, multidisciplinary rehabilitation, massage, cognitive-behavioral therapy, cognitive functional therapy, and acupuncture also are helpful for chronic low back pain. Closed-loop spinal cord stimulation may be helpful in otherwise refractory cases of back and leg pain, but its benefit is limited. Stem cell therapy is also being evaluated for the treatment of chronic discogenic pain.
Surgery
Referral to a spine surgeon is appropriate if an operation may be indicated, for confirmation of advice not to have surgery, or if the patient or family requests a consultation. Even in the absence of radicular pain or myelopathy, surgical intervention for neck pain is indicated in cases of vertebral instability, such as caused by fracture, tumor, or infection. For neck pain that is accompanied by signs or symptoms of radiculopathy, surgery should be considered but is not usually the initial treatment. If a cervical spine lesion is causing spinal cord compression, evaluation for possible surgery is indicated.
When persistent nonradicular lower back pain is accompanied by degenerative spine changes, surgical fusion is often performed. However, randomized controlled studies have shown that lumbar spinal fusion is only modestly helpful compared with no treatment, and lumbar fusion is not beneficial compared with an active physical therapy program. Total disc arthroplasty (artificial disc) can be used for cervical radiculopathy or myelopathy but not for neck pain alone. Total lumbar disc arthroplasty is available, but little used for chronic lower back pain.
Prognosis
Between 50 and 85% of patients who have neck pain that persists for more than a day report recurrence of symptoms in 1- and 5-year follow-up. About 50% of patients recover within 3 months. Patients who remain symptomatic generally have relatively mild pain and disability. Factors that increase the likelihood of developing persistent or recurrent neck pain include prior neck injury, psychopathology, low work satisfaction, poor workplace environment, female gender, concomitant low back and other pain disorders, poor coping skills, neck trauma, sedentary lifestyle, and weight gain. Patients with neck pain following a whiplash injury are especially likely to experience protracted symptoms.
Mechanical low back pain, even with radicular symptoms, resolves without specific intervention within 30 days in most patients and within 3 months in 90% of patients. Exercise alone or in combination with education is effective for preventing low back pain. Recurrence is frequent, however, and about 50% of patients will experience another episode within 1 year. Many patients will have lingering fluctuating or intermittent low back pain, but only a minority develop significant chronic low back pain.
Long-term disability is more common with obesity, low education level, tobacco use, high levels of pain at the onset, tendency to somatization, job dissatisfaction, lack of availability of light-duty employment, and need to perform heavy lifting at work. Genetic variability, such as in polymorphisms of catechol O -methyltransferase, also may play a role in the development of chronic pain.
Lumbar Spinal Stenosis
Definition
Lumbar spinal stenosis occurs when narrowing of the lumbar spinal canal, its lateral recesses, or neural foramina causes symptomatic or asymptomatic compression of the lumbosacral nerve roots. L4-5 is the most common level of stenosis, followed by L3-4, L2-3, L5-S1, and L1-2; most patients have stenosis at more than one vertebral level.
Epidemiology
Congenital spinal stenosis occurs in about 7% of the general population, and midsagittal degenerative stenosis occurs in about 30%. More severe stenosis is associated with older age and more low back pain. About 10% of patients have spinal stenosis in both the cervical and lumbar levels. Patients with diffuse idiopathic skeletal hyperostosis are especially likely to develop spinal stenosis.
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