Principles of Ambulatory Medicine, 7th Edition

Chapter 71

Low Back Pain

David G. Borenstein

Low back pain is one of the most common human afflictions. Between 70% and 80% of the population experiences back pain some time during their lives. The prevalence of back pain reported ranges from a low of 10% of adults during a 2-year period to a high of 20% of the population of a Western industrial society during a 2-week period. Although as many as 30% of people with back pain do not seek medical evaluation, the remainder eventually request medical advice. The office is the appropriate setting for the evaluation of these patients. A review of three time periods (1980–1981, 1985, and 1989–1990) studied by the National Ambulatory Medical Care Survey revealed mechanical low back pain (defined below) as the fifth most common reason for all physician office visits. Nonspecific low back pain was the most common diagnosis, accounting for 56.8% of these cases (1). Most patients with low back pain have underlying conditions that can be diagnosed and treated in the ambulatory setting. Most patients do not require expensive imaging tests, hospitalization, or surgery. The task is to separate the few who require more aggressive assessment from those who will recover with only office evaluation and conservative management.

 

FIGURE 71.1. Anatomic relationships of the lumbosacral spine. A: Lateral view. B: Posterior view. C: Cross-sectional view.

P.1166

Anatomy and Biomechanics of the Lumbosacral Spine and Associated Structures

The structure of the lumbosacral spine is complex (Fig. 71.1A–C). The lumbar spine is composed of five vertebrae with interposed intervertebral disks that consist of a gelatinous nucleus pulposus and a surrounding annulus fibrosus. The vertebrae and disks are supported by strong ligamentous structures and paraspinous muscles. The posterior aspects of the vertebrae surround the spinal canal, form the neural foramina, and interlock to form apophyseal joints (facet joints) whose main purpose is motion (Fig. 71.1A–B). The sacrum is the part of the spine that interdigitates with the iliac bones to form part of the pelvis.

An understanding of the nerve supply to the lumbosacral spine is essential to recognizing the patterns of pain associated with disease processes that affect components of the back. The sinuvertebral nerve (Fig. 71.1C) is the major sensory nerve supplying structures in the lumbar spine. The nerve arises from the corresponding spinal nerve before it divides into anterior and posterior branches. The nerve enters the intervertebral foramen and divides into ascending, descending, and transverse branches that anastomose with the contralateral side and with sensory nerves at adjacent levels above and below. The sinuvertebral nerve supplies the posterior longitudinal ligament, superficial annulus fibrosus, epidural blood vessels, anterior dura mater, dural sleeve, and posterior vertebral periosteum. The posterior rami of the spinal nerves supply the apophyseal joints above and below the nerve and the paraspinous muscles at multiple levels. The complex innervation of lumbar spine structures helps explain the diffuse nature of pain associated with a wide variety of disorders.

A number of organs are situated in the retroperitoneum, anterior to the lumbar spine. The kidneys, ureters, aorta, inferior vena cava, pancreas, and periaortic lymph nodes are retroperitoneal organs. Diseases that affect these organs may result in referred pain that is localized to the lumbar spine.

In the upright position with a normal spinal curvature (lordosis), the ligamentous structures maintain the position of the spine with little need for contraction of the paraspinous muscles or for weight-bearing by the apophyseal (facet) joints (Fig. 71.1A). However, if the normal curve is flattened or accentuated, the paraspinous muscles contract and the apophyseal (facet) joints become weight-bearing. This change in body mechanics results in pain.

The lumbar vertebrae are exposed to tremendous forces. This is caused principally by the magnification of stresses that result from the lever effect of the arm in lifting and by vertical forces associated with the human upright position. Figure 71.2 shows how lifting an object away from the body introduces the lever magnification phenomenon, resulting in a marked increase in forces on

P.1167


the vertebral bodies and disks. Because each intervertebral disk is a fluid system, hydraulic pressure is created whenever a load is placed on the axial skeleton. This hydraulic pressure magnifies three to five times the force that occurs on the annulus fibrosus. This force is akin to the hoop stress that occurs in a barrel when pressure is applied to its liquid content. A study using a pressure transducer placed in vivo in the nucleus pulposus of an asymptomatic 45-year-old man documented highest intradiscal pressures associated with lifting a 20-kg weight. The lowest intradiscal pressures were associated with the prone position (2). The ability of the annulus fibrosus to withstand stress in any position decreases significantly with age, and by age 60 years many people have only 50% of the strength in these fibers that they had at age 30 years. Alterations in the nucleus pulposus associated with oxidative damage and the appearance of reparative collagen as a manifestation of disk degeneration are observed in pathology specimens obtained from individuals as early as the adolescent years (3).

 

FIGURE 71.2. Forces in the lumbar area.

However, the lumbar spine is not just an isolated structure. Much support is obtained by the muscles and ligaments of the spine and by the muscles of the thoracic and abdominal cavities. These latter structures act as a sort of muscular cylinder that helps decrease the load on the axial skeleton by as much as 30% in the lumbar area and 50% in the thoracic spine.

Evaluation of Patients with Low Back Pain

Certain facts pertaining to the causes and natural history of back pain influence the evaluation and treatment of patients with this symptom. Back pain is most often associated with a mechanical cause, although it sometimes has a nonmechanical (called medical or systemic in this text) cause. Mechanical low back pain may be defined as pain secondary to overuse of a normal anatomic structure (e.g., muscle strain) or deformity of an anatomic structure (e.g., herniated nucleus pulposus). Medical back pain syndromes are simply the manifestation, in the area of the lower back, of a systemic disorder. These are defined more fully below (see Approach to Diagnosis and Treatment of Low Back Pain). Most patients with mechanical back pain do not have an associated history of acute trauma, lifting, or strain. Most low back pain problems are self-limited. Of patients evaluated by physicians, 40% to 50% are better in 1 week, 51% to 86% in 1 month, and 92% within 2 months (4). Although most patients have resolution of their episode of back pain within 2 months, as many as 75% may have a relapse within the next 12 months (5). Most patients with low back pain do not require surgery.

History

Questions about back pain should concentrate on a history of episodes and, for the current episode, the onset, duration, frequency, location, radiation, time of day, quality, intensity, and the aggravating and alleviating factors. A history of motor or sensory nerve root irritation or sphincter (bladder or rectal incontinence) or sexual dysfunction is important in identifying patients with cauda equina compression (seePhysical Examination). Occupational history may reveal predisposing factors associated with recurrent episodes of back injury.

Patients should be questioned about systemic symptoms that are indicative of a medical (systemic) cause of their back pain. Patients with fever, weight loss, pain with recumbency, extended morning stiffness, acute bone pain, or viscerogenic pain should be evaluated for a systemic illness. Patients who are older than 50 years also are at greater risk for a medical (systemic) cause of their pain. A history of cancer is a “red flag” for a medical cause of low back pain (6).

P.1168

 

Physical Examination

Physical Examination of the Lumbosacral Spine and Associated Musculoskeletal Areas

Abnormalities of the spine may be discovered while the spine is stationary or in motion. The patient should be examined in an orderly fashion that evaluates the function of musculoskeletal and neurologic structures of the lumbosacral spine.

Initially, the patient is examined in a gown while he or she is standing barefoot or wearing only socks. The spinal column is examined from all directions to check for excessive kyphosis, lordosis, or scoliosis. The presence of scoliosis is best determined by having the patient flex at the waist with arms extended in front. Any asymmetry of the height of the shoulders can be appreciated. Any deviation of a spinous process from the midline is noted. Firm palpation of the paravertebral muscles and of each vertebral spine is performed. Isolated tenderness over a bone suggests a localized problem such as tumor, infection, or compression fracture. Firm paraspinous muscles result from spasm secondary to local injury or referred pain.

Mobility of the spine is assessed by having the patient bend forward and attempt to touch the toes (normal is approximately 50–80 degrees). However, the hip joints also participate in the movement. Range of flexion can be determined by quantifying the expansion of a 10-cm line measured from the lumbosacral junction superiorly during maximal flexion (Schober test, see Chapter 78) or noting the distance of the fingertips from the floor. During this movement the normally smooth rhythm of the reversal of the lumbar lordosis is noted. If the rhythm is interrupted or hesitant, an abnormality of the apophyseal joints or of paraspinous structures may be present.

Lateral flexion (normal is to approximately 30 degrees) and extension (normal is to approximately 30 degrees) are assessed. Lateral flexion usually is preserved in disk disease but may be limited in patients with a spondyloarthropathy (i.e., joint problem of the spine). Increased discomfort with extension suggests disease of the apophyseal joints or spinal stenosis.

The patient then is examined while he or she is bent forward over the examining table. In this position, the inferior portion of the sacroiliac joints, ischial tuberosities, and sciatic notch are more easily palpated.

The gait of the patient should be observed. Patients with back pain may walk in a stiff guarded fashion or may favor one leg if a radiculopathy is present.

The patient is next examined sitting with his or her legs dangling. The deep tendon reflexes of the knees (L4) and ankles (S1) are elicited to test the integrity of the reflex arcs. An absent reflex may signify nerve root impingement secondary to a herniated nucleus pulposus. The patient extends each knee while seated. Flexion of the hip and extension of the knee stretch the lumbar nerve roots. Radicular pain that radiates from the back to below the knee is associated with nerve root impingement. The origin of the pain from the nerve root can be confirmed by lowering the leg just to the point where the pain disappears and then reproducing the pain by dorsiflexing the foot. This sign, if positive, suggests a herniated intervertebral disk or, less commonly, bony impingement of a nerve root caused by arthritis affecting the apophyseal joints, lumbar stenosis, or, rarely, a tumor of the spinal cord or surrounding structures. This distracted straight-leg raising(SLR) test helps confirm the organic source of pain and identify patients who may exaggerate their symptoms. Patients with functional complaints have no discomfort with a distracted SLR test but may describe excruciating pain when the SLR test is done in the supine position. Not all patients with a herniated disk have a positive SLR test. A patient, especially older than 30 years, may have a herniated disk that is too small or in the wrong location to irritate the nerve roots.

Next, the patient assumes the supine position so that a standard SLR test can be performed. The examiner fully extends the knee and slowly flexes the lower extremity at the hip. Normally the hip can be flexed to 80 degrees without pain, except for discomfort in the thigh or behind the knee secondary to hamstring muscle tightness. A positive test is manifested by radicular pain that radiates below the knee on the affected side or bilaterally. The nerve root and surrounding dura do not move in the neural foramen until an elevation ≥30 degrees of the lower extremity has been reached. Therefore, radicular pain that is elicited at an elevation <30 degrees is suspect. The SLR test is sensitive but nonspecific for the presence of a herniated intervertebral disk causing sciatica (7). After the SLR test, the unaffected lower extremity should be raised, thus performing the crossed SLR test. This procedure causes tension and stretch of the nerve roots of the opposite (affected) lower extremity and reproduces the radicular pain caused by SLR in that lower extremity. The test is uncommonly positive, but when so there is a strong but not absolute correlation with disk herniation (8).

Next, sensory assessment of the buttock, perineum, and lower extremities should be performed. Chapter 86 shows the relevant sensory dermatomes that can be evaluated by pinprick and touch. Abnormalities help to localize a lesion and to determine the need and urgency of an orthopedic or neurosurgical consultation. An important component of the sensory assessment is the search for signs compatible with acauda equina syndrome (syndrome of neurologic dysfunction from compression of the nerves at the L4–5 level and inferior to the spinal cord proper, often secondary to a central disk herniation). The signs of compression of the cauda equina include saddle anesthesia, loss of anal sphincter tone (assessed by rectal examination), bilateral sciatica (pain in the distribution of the sciatic nerve), lower extremity motor weakness, and a history of bowel,

P.1169


bladder, or sexual dysfunction. This syndrome, if present, is an indication for immediate referral to a neurosurgeon or orthopedic surgeon for hospitalization and surgical decompression of the spinal cord. The best neurologic outcome occurs when decompression occurs in the first 48 hours after onset of cauda equina compression signs (9).

A detailed assessment of motor function of the lower extremities also helps localize a lesion in the patient in whom neurologic involvement is suspected (see Chapter 92). This assessment can be done while the patient is supine, sitting, or standing. Muscles tested include hip flexors (L2–3) and extensors (L4–5), knee extensors (L3–4), dorsiflexors of the foot (L4–5), knee flexors (L5–S1), and plantar flexors of the foot (S1–2). Subtle weakness may be elicited by having the patient walk on his or her toes (gastrocnemius muscle group, S1–2) and heels (tibialis anterior muscles, L4–5).

The hip, sacroiliac, and knee joints are assessed while the patient is in the supine position. The hip and knee joints are assessed by moving these joints through a normal range of motion when they are unweighted. Pain with motion suggests an articular cause of leg pain. Thesacroiliac joint is assessed by the Patrick or FABER (flexion, abduction, external rotation) test. The test is done by positioning the lateral malleolus of the tested leg on the patella of the opposite leg. Downward pressure is placed on the medial aspect of the knee while the pelvis is stabilized by placing a hand on the contralateral anterior superior iliac spine. Pain associated with a quick pulse or downward pressure usually is localized to the lateral aspect of the lumbar spine and originates in the sacroiliac joint. Slow pressure may elicit groin pain indicative of hip joint dysfunction.

The sacroiliac joint and muscles of hip abduction (L2–3) are tested while the patient is in the lateral position. Pressure is applied to the iliac wing, compressing the sacroiliac joints. Pain felt in the sacroiliac joint suggests an intra-articular process or a strain of the posterior sacroiliac ligaments. The muscles of hip abduction are tested as the patient elevates the upper leg against downward pressure applied below the knee by the examiner.

The symmetry of the buttocks is assessed (gluteus maximus, L5, S1–2) while the patient is in the prone position. A femoral stretch test (i.e., extending the hip joint) elicits pain in the anterior thigh (L2–3) or the medial aspect of the leg (L4) in patients with corresponding herniated intervertebral disks.

To evaluate the rare patients suspected of malingering or of having a psychiatric origin for their back pain, Waddell et al. (10) identified five physical signs associated with functional disorders. First, overreaction during examination was found to be the single most important sign indicating a nonorganic cause. Overreaction may take the form of collapsing, sweating, tremors, muscle tension, bizarre facial expression, or disproportionate verbalization. Second, simulation testing can be used to elicit nonorganic pain. Two useful examples are axial loading and rotation. In the first example, with the patient standing, low back pain is reported in overreactors (but not in others) on vertical loading by pressing down on the patient's head. Neck pain is common during this examination in all and does not constitute a positive sign. In the hip rotation test, the patient stands with feet together and arms fixed firmly to the lateral sides of the body at the hip level by the examiner's hands. In this manner, the torso (and the spine) is passively rotated on the hips. Because the units of the spine itself are not moved, reports of low back pain are a positive sign of a nonorganic cause. However, in the presence of true radiculopathy, leg pain may be produced because there is movement at the hip joint, and nerve roots may be stretched. Third is the use of distraction testing. This consists of observing the patient during the course of the examination for variable findings when the patient is unaware of being observed or tested, such as during the distracted SLR (see Physical Examination of the Lumbosacral Spine and Associated Musculoskeletal Areas). Fourth, superficial, nonanatomic, or variable tenderness is a nonorganic sign. A useful technique is the Magnuson test, in which tender areas are subtly marked and later examined again for reproducibility. Fifth, motor or sensory findings that are not explained by an anatomic lesion provide clues that the problem is psychiatric in origin. Also, sudden giving away or flaccidity of a muscle during strength testing of the symptomatic area supports a nonorganic problem. A finding of at least three of the five types of signs is clinically significant. The presence of positive findings is not correlated absolutely with malingering. These individuals require treatment for physical problems in association with a complete psychological assessment (11).

Examination of Other Regions

Patients with constitutional symptoms or with symptoms not attributed to a local process in the back (e.g., abdominal pain) should undergo a focused physical examination. The physical examination, including pelvic and rectal and breast examinations in women, is particularly important in patients who describe new back pain and are 50 years of age or older.

Common origins of metastatic cancer to the spine are the breast, lung, prostate, thyroid, kidney, and rectum. Referred pain from cancer or other lesions may also be felt in the back. For example, pancreatic tumors or duodenal ulcers cause pain to be referred to the high lumbar or low thoracic vertebral region. Bowel or urinary tract cancer may cause pain to be referred to the mid or low lumbar region, and a disease process located in the pelvis may cause lower lumbar or sacral pain. Neoplasia primarily affecting the bones, especially multiple myeloma, is an important consideration in the elderly.

Assessment of the adequacy of the arteries of the lower extremities is important. Vascular abnormalities

P.1170


may cause pain due to ischemia in the back, buttock, or lower extremities during exertion. In addition to diminished pulses and bruits over arteries, cutaneous signs of ischemia (ulcers, loss of hair or nails) should be sought in the legs or feet (see Chapter 94). Sudden change in a pain pattern associated with an abdominal aneurysm or an episode of hypotension should alert one to the possibility of impending extension or rupture of the aneurysm.

Although the physical examination adds essential information to the evaluation of low back pain, the reproducibility of findings can vary widely among examiners and at different times. In one study of the physical examination of patients with low back pain, McCombe et al. (12) evaluated the reproducibility of a number of signs. They concluded that precise examination, careful measurement of locations of pain and tenderness and degrees of movement of the back and legs, and careful documentation of the findings were most important to accurately reproducing a patient's physical signs. Certain caveats relevant to this examination were developed. The most important among these were as follows:

  • Bony tenderness is more reproducible and of greater diagnostic significance than soft-tissue tenderness.
  • Pain on hip flexion and external rotation is reproducible and valuable.
  • Heel and toe standing are not an accurate method of assessing muscle strength.
  • SLR test is reliable and reproducible if measurement and documentation of the extent of pain radiation are precise.
  • Measurements of the range of flexion and lateral bend are reliable.

A study by Jensen (13) of the accuracy of certain signs in predicting a precise cause and location of a problem showed a reasonable but imperfect correlation of disturbed sensory and motor function with anatomic abnormalities confirmed at surgery in 52 patients with lumbar disk herniations. The time of day of the examination also may have an effect on physical findings. Ensink et al. (14) measured lumbar spine motion in 29 patients with chronic back pain in the morning and afternoon. Flexion was increased to the greatest degree at the end of the day, and extension was independent of time of measurement. The sum of all these studies is that careful examination and precise measurements of dysfunction and pain location are important in evaluating back pain. However, no sign is absolutely diagnostic or perfectly reproducible, and some signs are frankly unreliable. The entire constellation of findings must be considered in developing a proper approach to a patient.

With information obtained from the history and physical examination, a working diagnosis can be generated based on first defining the pain as mechanical or nonmechanical (medical or systemic) in nature. Patients with mechanical disorders may be treated without additional laboratory or radiographic tests during the initial visit. On the other hand, those believed to have a nonmechanical (medical or systemic) problem should undergo further diagnostic testing.

Laboratory Evaluation

Radiographic Assessment

plain x-ray film of the lumbar spine is not a necessary part of the initial evaluation of patients with back pain unless they have a history of recent major trauma or acute constitutional symptoms. Patients with back pain of a mechanical origin often have normal x-ray films. In addition, many patients with abnormal x-ray films may be entirely asymptomatic. By age 50 years, 67% of normal people have evidence of disk disease characterized by narrowing of one or more disk spaces or disk calcifications; an additional 20% of people have lumbar osteophytes. In fact, only 13% of 50-year-olds have normal x-ray films. Two thirds of patients with roentgenographic evidence of lumbar disk degeneration are asymptomatic. Osteoarthritis of the apophyseal (facet) joints is not correlated with symptoms. In addition, plain films may not be sufficiently sensitive to identify bony lesions unless 50% of the medullary portion of the bone has been destroyed. Therefore, plain x-ray films of the lumbar spine should be obtained only in patients who have not responded to a course of conservative therapy, persist with pain, have reflex asymmetry, have point vertebral tenderness, or are elderly and have new-onset pain (because of the higher incidence of a fracture or a systemic cause of their symptoms) (15). In patients with exacerbation of low back pain with extension of the spine, radiographs of the lumbar spine identify facet joint alterations that are more likely associated with clinical symptoms (16).

Other radiographic techniques that are useful in the evaluation of patients with back pain include bone scan (infection, tumor [but multiple myeloma is notoriously missed], arthritis, fracture), computed tomography (CT; disk herniation, spinal stenosis, myeloma, retroperitoneal structures), and magnetic resonance imaging (MRI; disk herniation, intraspinal tumors). Each should be highly selected on the basis of the history and physical examination, and often a consultation with a radiologist, rheumatologist, neurosurgeon, or orthopedist is helpful in deciding the approach. MRI can detect specific anatomic lesions in the lumbar spine with greater sensitivity than any other radiographic technique (17). MRI detects degenerative intervertebral disk disease and spinal stenosis and is an excellent method for detecting medical disorders affecting the lumbar spine, including primary and metastatic malignancies and osteomyelitis (18). Contrast MRI with gadolinium differentiates scar tissue from recurrent disk herniations

P.1171


in individuals who have undergone surgical discectomies. CT is especially valuable for the definition of trabecular architecture of bone. Benign and malignant tumors and infectious lesions may be differentiated by CT. Radiographic findings become significant only when the history, physical examination, and radiographic findings agree. These more expensive imaging techniques are confirmatory, not diagnostic, tests. Nearly one third of asymptomatic patients have identifiable abnormalities that are of no significance (19). MRI scans have no value in predicting those individuals who will develop back pain over extended periods of time (20).

Other Laboratory Evaluations

Most patients with low back pain do not require laboratory studies with their initial evaluation. Patients who are elderly, have constitutional symptoms, or have not responded to conservative therapy may benefit from a laboratory evaluation (see Radiographic Assessment). The laboratory evaluations that may be useful include complete blood count and erythrocyte sedimentation rate (inflammatory and neoplastic disorders), serum calcium concentration and alkaline phosphatase activity (diffuse bone disease), serum and urine electrophoresis (multiple myeloma), prostate-specific antigen (metastatic prostate cancer), urinalysis (renal disease), and occult blood in the stool (ulcers, gastrointestinal tumors). All such evaluations should be based on distinct diagnostic possibilities based on the history and physical examination.

Electrophysiologic tests are not a substitute for neurologic evaluation of patients with back and leg pain. Electromyographic and nerve conduction tests should be reserved for individuals in whom the spinal nerve root level causing leg pain is unclear (21).

Approach to Diagnosis and Treatment of Low Back Pain

When describing various conditions that result in back pain, it is useful to place them into two categories: regional (mechanical) and medical (systemic or nonmechanical). Differentiating medical back pain syndromes from a mechanical cause can be difficult when the back is the only anatomic area in which symptoms are manifest. This difficulty is most commonly experienced when evaluating elderly patients. In many patients, a specific causative pathologic entity causing pain is not demonstrable in many individuals (22). Systemic conditions that typically affect the low back region, including infections and tumors, are discussed below.

Most patients with acute onset of low back pain have a regional (mechanical) cause of their symptoms. Up to 90% of these patients respond to a course of conservative medical therapy. Back pain may resolve in as few as 2 weeks in a significant number of patients (23). Serial observation is important in the management of patients with back pain. If symptoms or signs of progression or of incomplete response to treatment are present on reassessment, evaluation for an alternative diagnosis is indicated. The followup contact should occur 3 to 4 weeks after the initial visit for all patients because by this time most patients with nonserious disorders as the cause of their symptoms are markedly improved. The followup visit also is important for patients whose back pain has resolved so that they have an opportunity to be educated with regard to recurrent symptoms and advised regarding prophylactic measures.

Common Regional (Mechanical) Back Syndromes

Lumbosacral Strain Syndrome

Lumbosacral strain is the most common cause of low back pain. The cause of back strain is not always clear but may be related to muscular, ligamentous, or fascial strain secondary to either a specific traumatic episode or continuous mechanical stress. People between the ages of 20 and 40 years are at greatest risk of developing muscle strain. Predisposing factors include failure to use good techniques in lifting, obesity, abnormal forward pelvic tilt (accentuated lordosis, most usually an acquired posture resulting from abdominal obesity), and leg-length discrepancy.

Diagnosis

The patient complains of pain that may be severe in the back, buttock, or one or both thighs. Usually symptoms follow a recent increase in physical activity, such as gardening, lifting, or participating in an infrequently played sport. Usually the patient experiences no (or minimal) discomfort during or immediately after the activity. Within the next 12 to 36 hours, as the soft tissues swell, pain develops and is associated with a feeling of muscular stiffness. The patient complains of pain that is accentuated by standing and bending and alleviated by lying. Table 71.1 provides information useful in the differential diagnosis of mechanical low back pain.

Examination of the back may show nonspecific signs of muscle spasm and loss of lumbar lordosis, but characteristically no evidence of nerve root impingement is seen. Pain radiating to the low back from an inflamed ischial or trochanteric bursa is occasionally seen, but marked tenderness over the inflamed bursa should reveal the correct diagnosis (see Chapter 74).

TABLE 71.1 Information Useful in the Differential Diagnosis of Mechanical Low Back Pain

Characteristics

Lumbosacral Strain

Herniated Nucleus Pulposus

Osteoarthritis

Spinal Stenosis

Age (yr)

20-40

30-50

>50

>60

Pain characteristics

 

 

 

 

   Location

Back (unilateral)

Back and leg (unilateral)

Back (bilateral)

Leg (bilateral)

   Onset

Acute

Acute (prior episodes)

Insidious

Insidious

   Standinga

+

-

+

+

   Sittinga

-

+

-

-

   Bendinga

+

-

-

-

Straight-leg raising test

-

+

-

+

 

 

 

 

(stress, i.e., after walking)

Plain x-ray film

-

-

+

+

a+, Exacerbating; -, alleviating.
Adapted from Borenstein DG, Wiesel SW, Boden SD. Low back and neck pain: medical comprehensive diagnosis and management. Philadelphia: WB Saunders, 2004, with permission.

P.1172

 

Management

In December 1994, the Agency for Health Care Policy and Research (AHCPR; now the Agency for Healthcare Research and Quality) published a Clinical Practice Guideline booklet on the diagnosis and management of acute low back pain (24). The booklet included the recommendations of a 23-member panel that critically reviewed 3,918 published scientific articles. Table 71.2 lists the recommendations. The reviewed articles related to management were rated from A to D, ranging from studies with strong research-based evidence to studies in which the design did not meet inclusion criteria. The final recommendations were based on the strength of evidence, risk/benefit ratios, and cost of each intervention. In the absence of controlled trials, the potential benefit of an intervention had to outweigh its possible risks to be considered cost-effective.

In general, the guidelines encourage early return of function. The recommended medications have mild toxicities and little abuse potential. Invasive therapies are limited to patients who do not improve over 4 to 12 weeks. The guidelines do have limitations: the recommendations are options and not the sole method for treating low back pain; they are based on a small number of studies (although many were reviewed), and they are made for patients with acute low back pain and do not apply to patients with chronic low back pain. These guidelines have not been updated since their initial publication. Reviews of the relative value of diagnostic tests and therapies appear in the literature, but no comprehensive revision of recommendations for acute low back pain is extant (25).

Conservative therapy of low back pain from lumbosacral strain includes controlled physical activity (low stress, gradually increasing aerobic and back-strengthening exercises), physical therapy, nonsteroidal anti-inflammatory drugs (NSAIDs), and muscle relaxants. In a study of medical therapy for low back pain with or without leg pain, the combination of an NSAID and a muscle relaxant was associated with the greatest number of individuals with improvement at 1 week (26). To minimize back motion and provide support, the bed should be firm but comfortable. A bed board cut from 5/8-inch plywood placed between the mattress and box spring usually is effective. Avoiding strenuous activity for most patients is appropriate, and even for those with severe pain, a minimal period of strict bed rest as short as 2 days has been shown to be adequate in relieving back pain (27). Controlled physical activity allows injured tissues to rest, permitting a greater opportunity for healing without reinjury. Pushing this concept further, Malmivaara et al. (28) reported on the efficacy of ordinary activity as tolerated in comparison with efficacy of bed rest for 2 days and back-mobilizing exercises. Better recovery, improved function, and fewer missed work days were associated with ordinary activity. Other studies also have reported the benefits of continuation of usual activities for recovery of low back pain (29). Faas et al. (30) showed the absence of significant benefit in the resolution of low back pain from exercise taught and monitored by a physiotherapist. In this study of 473 patients, flexion and stretching exercises were only minimally better at decreasing the duration of low back pain recurrences and had no other benefit compared with placebo interventions, which consisted of ultrasonography by a physiotherapist and usual care. The important lesson is that one should encourage the patient to do gentle activity as tolerated early in the course of acute low back pain when the cause is believed to be secondary to lumbosacral strain.

Physical therapy modalities, in the form of cold (ice massage) initially or heat subsequently, may decrease pain and diminish muscle spasm. Application of dry heat by a heating pad for 20 to 30 minutes several times per day (on low or medium setting with a protective towel between skin and pad to prevent burns) is preferred by some patients.

P.1173


Others prefer moist heat, which is accomplished by using hot towels or a heat pack, which produces sustained heat for up to 30 minutes (available at pharmacies). Application of a continuous low-level heat wrap is as effective as an NSAID for treatment of acute low back pain (31).

TABLE 71.2 Agency for Health Care Policy and Research Guidelines for Management of Acute Low Back Pain

1. Patient education
Patients with acute low back problems should be given accurate information about the following (strength of evidence = B):

1. Expectations for both rapid recovery and recurrences of symptoms based on natural history of low back symptoms

2. Safe and effective methods of symptom control

3. Safe and reasonable activity modifications

4. Best means of limiting recurrent low back problems

5. Lack of need for special investigations unless danger signs are present (see text)

6. Effectiveness and risks of commonly available diagnostic and further treatment measures to be considered should symptoms persist

2. Medications
Acetaminophen and NSAIDs

1. Acetaminophen is reasonably safe and is acceptable for treating patients with acute low back problems (strength of evidence = C).

2. NSAIDs, including aspirin, are acceptable for treating patients with acute low back pain (strength of evidence = B).

3. NSAIDs have a number of potential side effects. The most common complication is gastrointestinal irritation. The decision to use these medications can be guided by comorbidity, side effects, cost, and patient and provider preference (strength of evidence = C).

3. Physical treatments
Spinal manipulation

1. Manipulation can be helpful for patients with acute low back problems without radiculopathy when used within the first month of symptoms (strength of evidence = B).

2. A trial of manipulation in patients without radiculopathy with symptoms longer than a month probably is safe, but efficacy is unproven (strength of evidence = C).

4. Activity modification
Activity recommendations for bed rest and exercise

1. A gradual return to normal activities is more effective than prolonged bed rest for treating acute low back problems (strength of evidence = B).

2. Prolonged bed rest for >4 days may lead to debilitation and is not recommended for treating acute low back problems (strength of evidence = B).

3. Low-stress aerobic exercise can prevent debilitation due to inactivity during the first month of symptoms and thereafter may help to return patients to the highest level of functioning appropriate to their circumstances (strength of evidence = C).

Ratings for strength of evidence: A, strong research-based evidence (multiple relevant and high-quality studies); B, moderate research-based evidence (one relevant high-quality, or multiple adequate studies); C, limited research-based evidence (one adequate scientific study); D, studies did not meet inclusion criteria.
NSAIDs, nonsteroidal anti-inflammatory drugs.

Nonnarcotic analgesics such as NSAIDs help make patients comfortable while their injury heals. NSAIDs with rapid onset of action (e.g., aspirin 600 mg four times per day, ibuprofen 400–800 mg three times per day, diflunisal 500 mg twice per day, ketoprofen 25–50 mg three to four times per day, diclofenac 50 mg three times per day, or naproxen 250–500 mg twice per day) are most appropriate. In general, all NSAIDs should be used for a limited time (e.g., 2–6 weeks) when treating patients with acute mechanical back pain. The choice of any of these NSAIDs must be made in consideration of both patient and drug characteristics. For example, some patients prefer twice-per-day drug administration, whereas a few prefer more frequent dosing. In general, NSAIDs are effective for short-term symptomatic relief of low back pain but are less effective for sciatica (32). A systematic review of NSAID studies has confirmed the benefit of the active drugs compared to placebo for acute low back pain (33). Some groups of patients are especially vulnerable to the side effects of these drugs. Particularly important are the gastrointestinal and renal toxicity that occur often in elderly patients, especially women, who take NSAIDs. These drugs must be used with great caution or avoided in this population. Chapter 77 describes NSAID use in detail.

The cytochrome cyclooxygenase-2 (COX-2) inhibitors decrease the risk for gastrointestinal toxicities in older patients. However, COX-2 inhibitors and nonselective NSAIDs have been associated with an increased number of cardiovascular events compared to placebo with variable durations of exposure. Therefore, the benefits and risks of these agents must be determined for each patient. For the older patient who is sensitive to NSAIDs, pain control with acetaminophen alone (or occasionally with small doses of a narcotic for a short time) is generally preferred. Narcotic analgesia may be an appropriate therapy for individuals with comorbid conditions that preclude the use of NSAIDs (34,35).

Muscle relaxants should be considered for the patient with significant muscle spasm on physical examination. Only a small number of clinical trials have defined the benefits of muscle relaxants (36). Clinical trials have reported the benefits of using cyclobenzaprine 5 mg three times per day compared to placebo in patients with acute muscle spasm of the lumbar or cervical spine (37). The 5-mg dose was as effective as the 10-mg dose but was associated with fewer toxicities, including sedation. An interesting finding of the study was the absence of any sedation in 71% of patients who had complete resolution of muscle spasm with the 5-mg dose. Taking the drug at least 2 hours before bedtime may limit early-morning drowsiness. The efficacy of

P.1174


cyclobenzaprine can be judged after a 7- to 10-day trial. If cyclobenzaprine is ineffective, other muscle relaxants that may be useful include methocarbamol 750 mg four times per day, chlorzoxazone 500 mg four times per day, or orphenadrine citrate 100 mg twice per day. Drugs used for muscle spasticity (e.g., tizanidine 1 or 2 mg at night) may be helpful in some patients. Diazepam is no more effective than placebo in improving back spasm.

Biofeedback, transcutaneous electrical nerve stimulation, and acupuncture are not recommended by the AHCPR for the treatment of patients with acute low back pain (24).

During the recovery period, the patient should be advised to avoid activities that greatly increase the forces applied to the lower spine (e.g., lifting, pushing, force on outstretched upper extremity, as when making beds or vacuuming, lurching, or bending). If the patient does not respond or pain recurs, the patient should be reexamined 3 to 4 weeks later to investigate the possibility of a medical (systemic) cause of back pain. If a mechanical cause remains the most likely diagnosis, a modification of drug therapy (prescribing an alternative nonsteroidal and, if needed, muscle relaxant drug) is indicated.

For the patient who is recovering satisfactorily, various exercise programs have been advocated. One simple back-strengthening exercise program combines isometric gluteal and abdominal muscle contractions and pelvic tilt (Fig. 71.3). These exercises, which are performed standing with the back against a wall, should be recommended as soon as tolerated. These exercises strengthen the muscles that support the spine and may relieve current symptoms and help prevent future episodes of back pain. The exercises should be performed for a few minutes four to six times per day. Exercises designed to strengthen the abdominal musculature, such as sit-ups with the knees flexed, increase intradiscal pressure, may exacerbate symptoms, and are not recommended (however, see Management of the Intercritical Period).

Braces are reserved for the occasional patient with persisting back pain who must remain active while healing continues. However, only limited data support their use. Lumbosacral supports theoretically help relieve back pain by increasing intra-abdominal pressure, which results in greater support of the vertebral column, allowing paraspinous muscles to relax. The lumbosacral support may be a cloth corset fitted with metal stays posteriorly or a smaller cloth brace with a molded plastic insert. The patient should be provided a prescription for the corset or brace, which will be fitted by an orthotist or physical therapist. The patient should use the support while working and then remove the appliance. Use of a lumbosacral support weakens supporting back muscles, so patients should be weaned gradually but steadily from their supports. It is important for this group of patients to return gradually to full activity because an abrupt return may cause a recurrence of low back pain. Although use of a prophylactic lumbar brace will not prevent the onset of low back pain, use of such a device seems to decrease the degree of pain workers experience while continuing to work (38).

Patient education is an important component of the healing process. Patient education can be as effective as an exercise program or chiropractic manipulation treatments at a much reduced cost (39). Patients should be informed about the natural history to recovery with low back pain. They should be made aware of the potential for recurrence of low back pain over the next 12 months. Individuals educated about their problem are less likely to be dissatisfied with their care. A number of educational materials with information that removes misconceptions regarding this common disorder are available (40,41).

Herniated Intervertebral Disk

The intervertebral disk is composed of the annulus fibrosus and the nucleus pulposus. The annulus fibrosus maintains pressure on the contents of the nucleus pulposus, allowing the intervertebral disk to cushion the forces placed on the spine. Tears in the annulus fibrosus allow the contents of the nucleus pulposus to herniate beyond their normal confines. Tears in the annulus may be associated with transient episodes of low back pain. Controversy exists regarding the amount of discomfort that is associated with anatomic alterations of intervertebral disks without modifications of surrounding structures. Discogenic back pain is the term associated with individuals with disk abnormalities who have pain reproduced by a provocative discogram (a procedure that involves injecting dye into an intervertebral disk). Studies have demonstrated the inability of discography to identify the level of disk disease that is causing an individual's low back pain (42). Considerable disagreement exists regarding the amount of back pain associated with this entity and its appropriate treatment (43).

Herniation of the nucleus may result in sudden severe pain if neural elements are compressed and inflamed by the nuclear contents (Fig. 71.4). A sudden pressure placed on the lumbar spine that may occur with flexion (e.g., bending over to lift a heavy object, lifting with the arms extended away from the body, a sudden lurch, or even a sneeze or cough) can precipitate the rupture. However, many patients who have a herniated disk do not give a history of injury or of a sudden increase in pressure. Lumbar disk disease is most common at the L4–5 and L5–S1 levels and is less common between the other vertebral bodies.

Diagnosis

Patients with herniated intervertebral disks complain of sharp lancinating pain. The pain radiates from the back down the leg in the anatomic distribution of the affected

P.1175


nerve root. The pain may be so severe that the patient resists examination and splints the back in an awkward position of lateral lumbar flexion and hip flexion. Patients with bilateral sciatica (pain in the distribution of the sciatic nerve L5–S1 roots [buttocks, posterior thighs, and extending below the knees]), progressive muscle weakness, or bladder or bowel incontinence should be evaluated for cauda equina compression (see Physical Examination). The diagnosis of acute intervertebral disk herniation is most likely when physical examination reveals signs of nerve root compression with loss of motor function, loss of deep tendon reflexes, or localized sensory deficit. Specific disk herniations may result in well-defined motor, sensory, and reflex deficits that aid in their diagnosis (Table 71.3). Patients with progressive neurologic deficits, particularly muscle weakness, should be referred to an orthopedist or neurosurgeon for close observation. These patients may benefit from early surgical intervention.

 

FIGURE 71.3. Exercises: abdominal muscles and pelvic tilt.

Documentation of the anatomic abnormality associated with radicular pain is necessary for patients who have continued pain despite a 3- to 4-week course of conservative

P.1176


therapy. A number of radiographic techniques may be useful for demonstrating disk herniation. In the past, CT and myelography were the preferred techniques for identifying herniated disks. In most circumstances, MRI examination has replaced the myelogram as the preferred test by most surgeons for documenting disk herniation. MRI readily identifies the location of herniated disks without the need for myelographic dye or radiation exposure (44). Preliminary studies suggest that uptake of MRI contrast (gadolinium) by sequestrated disks may identify abnormalities that will resorb spontaneously without the need for surgical excision (45). Electromyography occasionally is necessary for demonstrating the nerve root level associated with denervation of leg muscles. Electromyography also may be able to differentiate by the pattern of muscle involvement patients with herniated disk and those with peripheral sciatic nerve abnormalities secondary to another problem such as trauma, tumor, or piriformis syndrome. Piriformis syndrome is associated with compression of the sciatic nerve deep in the buttocks by the piriformis muscle. Compression of the nerve results in sciatic pain that may radiate to the foot, following no specific dermatome or association with definitive neurologic deficits. Electromyography is recommended only after consultation with an orthopedist, rheumatologist, neurosurgeon, or neurologist.

 

FIGURE 71.4. A: Normal disk. B: Herniated disk.

TABLE 71.3 Common Findings in Lumbar Disk Herniations

Level of Disk
Herniation

Nerve Root Compressed

Pain

Numbnessa

Weakness

Reflexes (Decreased or Absent)

L3-4

L4

Sacroiliac joint, hip, posterolateral thigh, anterior aspect of leg

L4 dermatome

Extension of knee (quadriceps)

Knee jerk

L4-5

L5

Sacroiliac joint, hip

L5 dermatome (includes great toe)

Dorsiflexion of great toe (extensor hallucis longus)

 

L5-S1

S1

Lateral aspect of leg and foot

S1 dermatome (includes lateral toes)

Unusual (plantar flexion of foot)

Ankle jerk

Massive midline lumbar disk herniation

Multiple roots in dural sac

Midline of back, posterior aspect of both thighs and legs

Perineum, posterior thighs, plantar aspect of feet

Paralysis of feet and sphincters

Absent ankle jerk

Cauda equina syndrome (usually L4 or L5)

aSee Figure 78.2.
Adapted from Vanden Briuk KD, Edmonson AS. The spine. In: Edmonson AS, Crenshaw AH, eds. Campbell's operative orthopaedics. St. Louis: CV Mosby, 1980, with permission.

P.1177

 

Management

For most patients with a herniated disk, treatment is nonoperative because 80% of patients respond to conservative therapy (see below) and are completely free of pain within 2 months. In patients whose pain and other neurologic abnormalities remit without surgical reduction of the disk, an adjustment of the annulus and posterior longitudinal ligament relative to the herniated disk fragment is the most likely reason for the diminution of edema, inflammation, back pain, and leg pain. Desiccation of the fragment may play a role in resolution of symptoms.

Conservative therapy consists of limiting physical activity, with the patient at bed rest in the semi-Fowler position (hips and knees flexed, supported by pillows) for 2 days. NSAIDs and muscle relaxants (as described above) and narcotic analgesics (if the pain is severe) should be prescribed. Physical therapy usually is unnecessary for patients with acute disk herniations. Active exercise programs may intensify acute symptoms and should be avoided. Therapy such as ultrasound, short-wave diathermy, heat packs, or cold packs may provide short-term pain relief only (as they do in lumbosacral pain) but do not alter disk lesions or have any long-term effect on symptoms. Lumbar traction has not been shown to be more effective than bed rest for treatment of lumbar disk disease and low back pain and is not indicated (46). Patients should be prescribed such a conservative regimen for 3 to 4 weeks, and if this therapy fails, they should be asked to consider an epidural corticosteroid injection. A series of three injections over 3 to 6 weeks may improve back and leg pain (47). Epidural injections can help reduce pain and improve sensory function early in the course of sciatica secondary to a herniated disk (48). Surgical decompression of the appropriate disk space is indicated for persistent pain resistant to conservative therapy. The size of the disk herniation does not correlate with a lack of response to conservative management. Large herniated disks are more likely to decrease in size as documented by CT and contrast MRI (49). New minimally invasive techniques are being used for the removal of accessible disk fragments. These surgeries are associated with less damage to paraspinous soft tissues. Further investigation is needed to determine the efficacy of these techniques, such as arthroscopic discectomy, in comparison with standard discectomies (50). For management of the intercritical period, seeManagement of the Intercritical Period.

Osteoarthritis and Spinal Stenosis

The lumbar spine is one of the common locations for osteoarthritis. This joint disease is associated with joint pain, stiffness, deformity, and limitation of motion. Alterations over time secondary to osteoarthritis result in loss of disk volume, increased pressure on apophyseal joints, and hypertrophy of soft tissue and bony structures, resulting in a decrease in the size of the spinal canal. Chapter 75 discusses osteoarthritis in full.

Diagnosis

Initially, patients may complain of pain after repeated episodes of hyperextension that traumatizes the apophyseal (facet) joints, resulting in stretching or tearing of the ligamentous capsule of the apophyseal joint. Typically, back flexion (bending forward) relieves the pain, whereas hyperextension (e.g., a painter working overhead) exacerbates it. Patients also may experience back pain related to gradual degeneration of the intervertebral disk or the development of osteophytes, either of which may impinge on a nerve root. Patients with lumbar osteoarthritis or degenerative disk disease describe back, buttock, or unilateral lower extremity pain. Examination usually reveals evidence of irritation of a specific nerve root, resulting in loss of a localized motor or sensory neurologic function or of an absent deep tendon reflex (L5–S1 disk, ankle or L3–4 disk, knee). The SLR test may be positive. Many of these patients respond to conservative therapy because the anti-inflammatory action of NSAIDs is effective in diminishing the swelling of soft tissues, which causes nerve impingement.

As patients grow older, particularly during the fifth to seventh decade, back symptoms become suggestive of impingement of multiple nerve roots at different levels on both sides of the spinal cord. Spinal stenosis occurs most commonly in men, who complain of chronic low back pain with unilateral or bilateral lower extremity discomfort that is exacerbated by extension of the spine while standing. They also may develop frank hyperesthesia or dysesthesias (Table 71.1). They also may have a history of disk surgery. Many patients with spinal stenosis have symptoms of claudication mimicking those of peripheral vascular insufficiency. These patients develop lower extremity pain while standing or walking or hyperextending the spine in the absence of any evidence of peripheral vascular disease. Painful paresthesias are present in the feet or legs and may radiate to the hip girdle or lower trunk. Patients may experience lower extremity numbness and weakness. These symptoms are relieved by rest or flexion of the spine (the patient may report relief by bending forward as if to tie shoelaces). Physical examination may show no abnormalities until the patient is asked to walk. In this regard, the patient suspected of having spinal stenosis should be walked until pain develops—sometimes this requires many minutes—and then examined in the sitting position; abnormal motor or sensory deficits may be present only after such increased activity. Other physical findings may include the loss of peripheral pulses and atrophic skin (51).

Plain x-ray films show degenerative changes in the apophyseal joints (facet joints) and decreased anteroposterior canal diameter. CT is the best diagnostic radiographic

P.1178


technique for demonstrating spinal stenosis because CT shows the narrowed canal or impingement of osteophytes on the intervertebral foramina.

Management

Most patients with spinal stenosis can be treated nonsurgically. Activities that bring on pain should be discouraged. Patients may respond to NSAIDs or a course of epidural corticosteroid injections (administered by a consulting rheumatologist, neurosurgeon, anesthesiologist, or orthopedist). Operative therapy for spinal stenosis is reserved for patients who are severely incapacitated by their condition. Surgery for spinal stenosis requires decompression of the bony impingement of the spinal cord and nervi erigentes. If vertebral instability is documented before surgery, fusion of the vertebral bodies also is accomplished. Postoperative relief of pain is seen within approximately 1 week and full recovery, when surgery is successful, within 1 month. Patients treated successfully with surgery have a more rapid and greater improvement in neurogenic claudication than medically treated patients. However, only two thirds of patients describe improvement with initial decompressive surgery (52). Also, medically treated patients have no severe deterioration of neurologic function. Therefore, medical treatment for 2 to 3 years before considering surgery seems to be a good approach for most patients with spinal stenosis (53). Another study reported that 80% of individuals experienced immediate postsurgical improvement of neurogenic claudication. At 4-year followup, 70% of the surgical group continued with improved symptoms compared with 52% of patients treated nonsurgically (54).

Medical (Systemic) Back Pain Syndromes

Spondyloarthropathies

Patients with spondyloarthropathies (ankylosing spondylitis, reactive arthritis, psoriatic spondylitis, enteropathic spondylitis) often complain of low back, buttock, or leg pain. These patients have morning stiffness as a major component of their symptom complex. Although back pain is the first symptom in a number of young patients, it is often associated with other symptoms and signs of the specific disorder (iritis, conjunctivitis, or skin rash). A clue to the presence of a spondyloarthropathy on physical examination is tenderness with percussion over the axial skeleton or sacroiliac joints. The sacroiliac joints may be painful when stressed while the patient is in the prone or supine position. Early identification of a patient with spondyloarthropathy is important because new therapies are available that prevent progressive calcification of spinous structures (55). Chapter 78 discusses conditions affecting the axial skeleton and sacroiliac joints.

Infections

Although rare, infection of the axial skeleton (osteomyelitis, discitis, or septic arthritis) must be considered in any patient with back pain (56). Osteomyelitis is an infection of the vertebral bodies. Discitis is an infection of the intervertebral disk. Septic arthritis of the back is an infection of the sacroiliac joints. Chapter 40 discusses these conditions in detail.

Vertebral Fractures

Vertebral compression fractures are common, especially among the elderly, and usually result from a flexion injury when the spine is abruptly flexed, for example, during jumping. Fractures conceivably could be classified as a regional (mechanical) cause of back pain. It is arbitrarily classified as a medical (systemic) cause of low back pain because it most typically occurs in the elderly and often is a manifestation of a systemic disorder such as osteoporosis. The thoracic spine is most commonly involved. The force needed to compress a vertebral body in healthy bone is considerable. However, when the bone is diseased, as occurs with osteoporosis, myeloma, metastatic cancer, or hyperparathyroidism, the injury may be insignificant. Pain usually is localized and immediate, although it may be delayed for several days after the fracture. Often tenderness over a single vertebra indicates the presence of a fracture, but an x-ray film is necessary to confirm the diagnosis.

Other radiographic techniques are useful for identifying the locations of fractures that may not be detected by plain x-ray films. A bone scan often is useful in demonstrating whether there are single or multiple fractures. CT or MRI is indicated for patients with compression fractures who also have neurologic deficits. These techniques can localize abnormalities associated with nerve impingement. Not all processes that weaken bone are detected by bone scan (e.g., multiple myeloma). Blood chemistries, including the concentration of serum proteins, and the serum and urine electrophoretic pattern of proteins are helpful in identifying patients with myeloma.

With lumbar or thoracic vertebral compression fractures, management includes rest, adequate analgesia, and gradual ambulation when the patient is free from severe pain. Medical therapy in the form of intranasal calcitonin may be beneficial in controlling fracture pain through the release of endogenous β-endorphin (57). Kyphoplasty is a percutaneous technique for reexpanding collapsed vertebral bodies through the use of an inflatable balloon and injectable bone cement. This technique offers pain relief with the potential for restoration of vertebral body height (58). A lumbosacral support or, for the patient with a thoracic vertebral fracture, a chairback or hyperextension brace may be helpful in alleviating pain. These items can be obtained by prescription from an orthopedic appliance shop.

P.1179


The pain from a vertebral fracture may persist for several months, although the severe and incapacitating component usually lasts for only 2 to 3 weeks.

Tumors

Tumors of the lumbar spine are unusual causes of back pain; however, these diseases are associated with the highest morbidity, mortality, and dysfunction. Patients with tumors of the lumbar spine usually have back pain as their initial complaint. Commonly, patients with tumor-associated pain have increased discomfort with recumbency. Physical examination demonstrates localized tenderness and neurologic dysfunction if the spinal cord or a nerve root is compressed. Although laboratory evaluation often yields nonspecific results, radiographic evaluation is useful in identifying the location and type of neoplastic lesion. In general, benign tumors are located in the posterior elements of vertebrae (spinous, transverse process), and malignant (both primary and metastatic) tumors are located in the anterior components of vertebrae (body). The most common neoplastic lesion of the lumbar spine is a metastatic tumor. The most common primary tumor located in the lumbar spine is myeloma. The definitive diagnosis of a tumor must be derived from histologic examination of biopsy material obtained from the lesion. The most effective therapy for both benign and malignant tumors is removal of the lesions that are accessible to surgical excision. When excision is impossible, partial resection, radiation therapy, corticosteroids, or chemotherapy may be indicated to control symptoms and compression of the spinal cord and nerve roots.

Referred Pain

Disease processes that affect organs in the retroperitoneum not only may cause pain locally but may refer pain in the distribution of the sensory nerve supplying the diseased tissue. Diseases of the vascular, genitourinary, and gastrointestinal systems may refer pain to the lumbar spine. Characteristically, referred pain is unaffected by the physical position of the patient. Patients usually have symptoms in the affected organ, raising the possibility of a medical cause of the patient's back pain (Tables 71.4 and 71.5).

Management of Chronic Back Pain

Although most patients with low back pain have complete remission of symptoms within 3 to 4 weeks, many patients experience a recurrence (5). Patients should return to the caregiver's office even if they have had a resolution of their pain. The purpose of these visits is to discuss ways to prevent recurrent attacks of back pain by focusing education on posture, weight control, exercise, and work activities. In addition, a small but significant number of individuals with low back pain have persistent pain resistant to therapies effective for acute episodes.

TABLE 71.4 Medical Causes of Low Back Pain

Systemic: Constitutional symptoms, severe localized pain, morning stiffness are clues suggestive of generalized disorder.
   Rheumatologic: spondyloarthropathies, polymyalgia rheumatica, fibromyalgia
   Infectious: vertebral osteomyelitis, Pott disease (tuberculosis of spine), discitis, septic arthritis, epidural abscess, herpes zoster
   Neoplastic:
   Benign: osteoid osteoma, osteochondroma, giant cell tumor
   Malignant: metastatic, multiple myeloma, chondrosarcoma, chordoma, lymphoma, retroperitoneal sarcoma, neural tumor
   Neurologic-psychiatric: neuropathic (Charcot) joints, femoral neuropathy, depression, hysteria
   Miscellaneous: vertebral sarcoidosis, Paget disease, retroperitoneal fibrosis
Referred pain: Absence of any tenderness, limitation of motion, or aggravation of pain or spasm during the physical examination is suggestive of referred pain (see Table 71.5 for dermatome to which pain from various visceral structures may be referred).
   Lower thoracic and upper lumbar pain from an upper abdominal disease process (e.g., pancreas)
   Low lumbar pain from a lower abdominal disease process (e.g., aortic aneurysm)
   Sacral pain from a pelvic problem (e.g., endometriosis, prostate cancer)

Figure 71.5 shows some correct and incorrect postures and practical advice that may be useful to give to patients

P.1180


who have experienced low back pain. Weight reduction is desirable in the obese patient, because excessive weight directly increases the load on the lower vertebral column and its supporting structures. Exercise initiated as soon as the acute pain subsides (usually 2–4 days after onset) may improve function and decrease pain (59). At a minimum, such exercises alert patients to their back problem, which increases the likelihood of performing daily activities in a way that may allow them to avoid reinjury. Prolonged bed rest weakens back muscles and should be avoided.

P.1181


Certain advice to the patient regarding lifting is prudent. Sudden loading of the spine when the back is flexed and the knees are straight markedly increases forces placed on the lumbar spine (Fig. 71.2) compared with a position where the knees are bent and the back is straight. Exercises that strengthen the quadriceps (extend knees) are theoretically sound for anyone who may have to lift at all. These exercises include swimming, cycling, or jogging on a flat even surface. The patient should be advised to exercise only if it does not initiate or increase back pain. In addition, because the abdominal muscles are important in supporting the spine when a weight is brought to bear on it, exercises that strengthen the abdominal muscles (Fig. 71.3) are helpful. Patient education is an effective component in the treatment of all patients who have experienced back pain. Education about such matters may improve a patient's lifestyle and the likelihood of returning to work. So-called back schools, which generally are conducted by physical therapists, have been organized in many work sites. However, a large controlled trial of an educational program to prevent low back injuries organized as a back school for postal workers failed to prevent work-associated back injury in employees with or without a history of back injury, although the knowledge of safe behavior was increased by the training (60).

 

FIGURE 71.5. Incorrect and correct postural attitudes.

TABLE 71.5 Dermatome to which Pain from Various Visceral Structures May Be Referred

Dermatomea

Viscera

L1

Kidney, ureter, body of uterus, abdominal aorta, small intestine

L2

Bladder, abdominal aorta, ascending colon

L3

Abdominal aorta

L4

Abdominal aorta

L5, S1, S2

S3

Rectum, anus, lower portion of bladder, cervix, upper vagina, prostate

S4

Rectum, anus, base of bladder, cervix, upper vagina, prostate

S5

aSee Figure 86.2 for cutaneous pattern of dermatomes.
Modified from Borenstein DG, Wiesel SW, Boden SD. Low back and neck pain. Philadelphia: WB Saunders, 2004;64, with permission.

Complementary therapies are used frequently for a variety of medical problems, including low back pain (61). A wide variety of therapies has been promoted for the therapy of low back pain, including spinal manipulation, massage, acupuncture, and magnets. Chapter 5discusses acupuncture and chiropractic.

Spinal manipulation seems to help many patients and has been recommended by the practice guidelines published by the AHCPR (24). These guidelines do not specifically recommend that manipulation be done by a chiropractor. Initial evaluation of low back pain by a chiropractormay not include screening evaluation with history and physical examination for systemic disorders. Also, chiropractors generally do not offer additional therapies beyond those offered by an experienced physical therapist. Patient satisfaction with chiropractors seems to be related to the chiropractor's willingness to spend more time with the patient and to listen to his or her concerns (62). Too often physicians and physical therapists do not show such a level of concern and may even minimize the patient's problems. Studies of manipulation of the back do not define precisely what a standard manipulation is or what it accomplishes physiologically, making comparisons of it with other treatments impossible. Concerns also arise between the applicability of manipulation to chronic low back pain versus acute back pain. In general, manipulation may be helpful but is of no greater benefit than conventional therapies (63).

Therapeutic massage has benefited many individuals with chronic low back pain. This therapy given once per week for 10 weeks has demonstrated benefit months after the last treatment. The efficacy of this form of treatment is limited to the availability of experienced massage therapists (64). This same study failed to identify significant benefit of acupuncture for chronic low back pain. Acupuncture techniques can vary, and this may have an effect on the outcome of a clinical trial. Anecdotally, patients have described benefit of additional analgesia associated with acupuncture treatments. Additional trials are warranted to determine the efficacy of this treatment.

Magnets have been suggested as effective for treatment of low back pain. A pilot double-blinded, placebo-controlled trial using magnets for low back pain demonstrated no significant difference between study groups (65).

The patient may need to modify work or athletic activities once an episode of back pain occurs. Of note, however, there is no convincing evidence to support the concept that heavy labor or lifting predisposes to the development of the initial episode of back pain. Certain factors do predispose patients to injury, including improper technique in lifting, sitting for prolonged periods or not at all during the workday, and sudden maximal physical activity (e.g., participation in an occasional vigorous game without conditioning). Furthermore, back pain occurs more often in people who consider their occupation to be physically hard and in those who believe their work to be stressful to the spine or who are dissatisfied with their work (66,67).

Specific References*

For annotated General References and resources related to this chapter, visit http://www.hopkinsbayview.org/PAMreferences.

  1. Hart LG, Deyo RA, Cherkin DC. Physician office visits for low back pain: frequency, clinical evaluation, and treatment patterns from a US national survey. Spine 1995;20:11.
  2. Wilke H, Need P, Caimi M, et al. New in vivo measurements of pressures in the intervertebral disc in daily life. Spine 1999;24:755.
  3. Nerlich AG, Schleicher ED, Boos N. 1997 Volvo award winner in basic science studies: immunologic markers for age-related changes of human lumbar intervertebral discs. Spine 1997;22:2781.
  4. Dillane JB, Fry J, Kalton G. Acute back syndrome: study from general practice. BMJ 1966;3:82.
  5. Van den Hoogen HJM, Koes BW, van Eijk JTM, et al. The prognosis of low back pain in general practice. Spine 1997;22:1515.
  6. Deyo RA, Rainville J, Kent DL. What can the history and physical examination tell us about low back pain? JAMA 1992;268:760.
  7. Vroomen PC, de Krom MC, Knottnerus JA. Diagnostic value of history and physical examination in patients suspected of sciatica due to disc herniation: a systematic review. J Neurol 1999;246:899.
  8. Vaz M, Wadia RS, Gokhale SD. Another cause of positive crossed-straight-leg-raising test. N Engl J Med 1978;295:779.
  9. Shapiro S. Medical realities of cauda equina syndrome secondary to lumbar disc herniation. Spine 2000;25:348.
  10. Waddell G, McCulloch JA, Kummel E, et al. Nonorganic physical signs in low-back pain. Spine 1980;5:117.

P.1182

 

  1. Main CJ, Waddell G: Behavioral responses to examination: a reappraisal of the interpretation of “nonorganic signs.” Spine 1998;2367.
  2. McCombe PF, Fairbank JCT, Cockersole BC, et al. Reproducibility of physical signs in low back pain. Spine 1989;14:908.
  3. Jensen OH. The level-diagnosis of a lower lumbar disc herniation: the value of sensitivity and motor testing. Clin Rheumatol 1987;6:564.
  4. Ensink F, Saur PMM, Frese K, et al. Lumbar range of motion: influence of time of day and individual factors on measurements. Spine 1996;21:1339.
  5. Jarvik JG, Deyo RA. Diagnostic evaluation of low back pain with emphasis on imaging. Ann Intern Med 2002;137:586.
  6. Borenstein D. Does osteoarthritis of the lumbar spine cause chronic low back pain? Curr Rheumatol Rep 2004: 6:14.
  7. Albeck MJ, Hilden J, Kjaer L, et al. A controlled comparison of myelography, computed tomography, and magnetic resonance imaging in clinically suspected lumbar disc herniation. Spine 1995;20:443.
  8. Alexander AR. Magnetic resonance imaging of the spine and spinal cord tumors. Spine State Art Rev 1988;2:499.
  9. Weishaupt D, Zanetti M, Hodler J, et al. MR imaging of the lumbar spine: prevalence of intervertebral disk extrusion and sequestration, nerve root compression, end plate abnormalities, and osteoarthritis of the facet joints in asymptomatic volunteers. Radiology 1998;209:661.
  10. Borenstein DG, O’Mara JW Jr, Boden SD et al. The value of magnetic resonance imaging of the lumbar spine to predict low-back in asymptomatic subjects: A seven-year follow-up study. J Bone Joint Surg 2001: 83A:1306.
  11. Albeck MJ, Taher G, Lauritzen M et al. Diagnostic value of electrophysiological tests in patients with sciatica. Acta Neurol Scand 2000;101:249.
  12. Deyo RA. Diagnostic evaluation of LBP: reaching a specific is often impossible. Arch Intern Med 2002;162:1444.
  13. Coste J, Delecocuillerie G, Cohen de Lara A, et al. Clinical course and prognostic factors in acute low back pain: an inception cohort study in primary care practice. BMJ 1994;308:577.
  14. Bigos SJ, Bowyer O, Braen G, et al. Acute low back problems in adults. Clinical Practice Guideline No. 14. AHCPR Publication No. 95-0642. Rockville, MD: Agency for Health Care Policy and Research, Public Health Service, U.S. Department of Health and Human Services, December 1994.
  15. Bouter LM, Pennick V, Bombardier C, et al. Cochrane back review group. Spine 2003;1215.
  16. Cherkin DC, Wheeler KJ, Barlow W, et al. Medication use for low back pain in primary care. Spine 1998;23:607.
  17. Deyo RA, Diehl AK, Rosenthal M. How many days of bed rest for acute low back pain? N Engl J Med 1986;315:1064.
  18. Malmivaara A, Hakkinen U, Aro T, et al. The treatment of acute low back pain: bed rest, exercises, or ordinary activity? N Engl J Med 1995;332:351.
  19. Rozenberg S, Delval D, Rezvani Y et al. Bed rest or normal activity for patients with acute low back pain: a randomized controlled trial. Spine 2002;27:1487.
  20. Faas A, Chavannes AW, van Eijk JTM, et al. A randomized, placebo-controlled trial of exercise therapy in patients with acute low back pain. Spine 1993;18:1388.
  21. Nadler SF, Steiner DJ, Erasala GN, et al. Continuous low-level heat wrap therapy provides more efficacy than ibuprofen and acetaminophen for acute low back pain. Spine 2002;27:1012.
  22. Koes BW, Scholten RJPM, Mens JMA, et al. Efficacy of non-steroidal anti-inflammatory drugs for low back: a systematic review of randomized clinical trials. Ann Rheum Dis 1997;56:214.
  23. van Tulder MW, Scholten RJPM, Koes BW, et al. Nonsteroidal anti-inflammatory drugs for low back pain: a systematic review within the framework of the Cochrane Collaboration Back Review Group. Spine 2000;25:2501.
  24. Mahowald ML, Singh JA, Majeski P. Opioid use by patients in an orthopedics spine clinic. Arthritis Rheum 2005;52:312.
  25. Borenstein D. Opioids: to use or not to use? That is the question. Arthritis Rheum 2005;52:6.
  26. Bernstein E, Carey TS, Garrett JM. The use of muscle relaxant medications in acute low back pain. Spine 2004;29:1346.
  27. Borenstein DG, Korn S. Efficacy of a low-dose regimen of cyclobenzaprine hydrochloride in acute skeletal muscle spasm: results of two placebo-controlled trials. Clin Ther 2003;25:1056.
  28. van Poppel MNM, Koes BW, van der Ploeg T, et al. Lumbar supports and education for the prevention of low back pain in industry: a randomized controlled trial. JAMA 1998;279:1789.
  29. Cherkin DC, Deyo RA, Battie M et al. A comparison of physical therapy, chiropractic manipulation, and provision of an educational booklet in the treatment of patients with low back pain. N Engl J Med 1998;339:1021.
  30. Dunkin MA. All you need to know about back pain. Atlanta, GA: Arthritis Foundation, 2002.
  31. Borenstein D. Back in control: a conventional and complementary prescription for eliminating back pain. New York: M Evans, 2001.
  32. Carragee EJ. Clinical practice. Persistent low back pain. N Engl J Med 2005;352:1891.
  33. Carragee EJ, Alamin TF, Miller JL et al. Discographic, MRI and psychological determinants of low back pain disability and remission: a prospective study in subjects with benign persistent back pain. Spine J 2005;5:24.
  34. Boden SD. The use of radiographic imaging studies in the evaluation of patients who have degenerative disorders of the lumbar spine. J Bone Joint Surg 1996;78A:114.
  35. Komori H, Okawa A, Haro H, et al. Contrast-enhanced magnetic resonance imaging in conservative management of lumbar disc herniation. Spine 1998;22:67.
  36. Beurskens AJ, de Vet HC, Koke AJ, et al. Efficacy of traction for nonspecific low back pain: 12-week and 6-month results of a randomized clinical trial. Spine 1997;22:2756.
  37. Spaccarelli KC. Lumbar and caudal epidural corticosteroid injections. Mayo Clin Proc 1996;71:169.
  38. Carette S, Leclaire R, Marcoux S, et al. Epidural corticosteroid injections for sciatica due to herniated nucleus pulposus. N Engl J Med 1997;336:1634.
  39. Komori H, Okawa A, Haro H, et al. Contrast-enhanced magnetic resonance imaging in conservative management of lumbar disc herniation. Spine 1998;22:67.
  40. Hermantin FU, Peters T, Quartararo L, et al. A prospective, randomized study comparing the results of open discectomy with those of video-assisted arthroscopic microdiscectomy. J Bone Joint Surg 1999;81A:958.
  41. Bell GR. Office evaluation of patients with spinal stenosis. Semin Spine Surg 1999;11:191.
  42. Herno A, Airaksinen O, Saari T, et al. Surgical results of lumbar spinal stenosis: a comparison of patients with or without previous back surgery. Spine 1995;20:964.
  43. Johnsson K, Uden A, Rosen I. The effect of decompression on the natural course of spinal stenosis: a comparison of surgically treated and untreated patients. Spine 1991;16:615.
  44. Atlas SJ, Keller RB, Robson D, et al. Surgical and nonsurgical management of lumbar spinal stenosis: four-year outcomes from the Maine Lumbar Spine Study. Spine 2000;25:556.
  45. Reveille J, Arnett FC. Spondyloarthritis: update on pathogenesis and management. Am J Med 2005;118:592.
  46. Alamin TF, Hanley EN. Profiles of patients with spine infections. Semin Spine Surg 2000;12:212.
  47. Gennari C. Analgesic effect of calcitonin in osteoporosis. Bone 2002;30[5 Suppl]:67S.
  48. Kasperk C, Hillmeier J, Noldge G, et al. Treatment of painful vertebral fractures by kyphoplasty in patients with primary osteoporosis: a prospective nonrandomized controlled study. J Bone Miner Res 2005;20:604.
  49. Hayden JA, van Tulder MW, Malmivaara AV, et al. Meta-analysis: exercise therapy for nonspecific low back pain. Ann Intern Med 2005;142:765–775.
  50. Daltroy LH, Iversen MD, Larson MG, et al. A controlled trial of an educational program to prevent low back injuries. N Engl J Med 1997;337:332.
  51. Eisenberg DM, Davis RB, Ettner SL, et al. Trends in alternative medicine use in the United States, 1990-1997: results of a follow-up national survey. JAMA 1998;280:1569.
  52. Cherkin DC, MacCornack FA. Patient evaluations of low back pain care from family physicians and chiropractors. West J Med 1989;150:351.
  53. Cherkin DC, Sherman KJ, Deyo RA et al. A review of the evidence for the effectiveness, safety, and cost of acupuncture, massage therapy, and spinal manipulation for back pain. Ann Intern Med 2003;138;898.
  54. Cherkin DC, Eisenberg D, Sherman KJ, et al. Randomized trial comparing traditional Chinese medical acupuncture, therapeutic massage, and self-care education for chronic low back pain. Arch Intern Med 2001;161:1081.
  55. Collacott EA, Zimmerman JT, White DW, et al. Bipolar permanent magnets for the treatment of chronic low back pain: a pilot study. JAMA 2000;283:1322.
  56. Bigos SJ, Battie MC, Spengler DM, et al. A prospective study of work perceptions and psychosocial factors affecting the report of back injury. Spine 1991;16:1.
  57. Krause N, Ragland DR, Fisher JM, et al. Psychological job factors, physical workload, and incidence of work-related spinal injury: a 5-year prospective study of urban transit operators. Spine 1998;23:2507.


If you find an error or have any questions, please email us at admin@doctorlib.info. Thank you!