Lower Back Pain

Low Back Pain

The accurate, objective study of low back pain (LBP), itsnatural history, and its effective treatment is difficult because of the multiple factors involved. This includes the

favorable natural history and spontaneous resolution of most LBP regardless of treatment, the presence of secondary and monetary gain for LBP in Western societies, and the methodological problems in setting up studies. The incidence of low back disability appears to have dramatically increased in Western society since about 1970. Waddell (1998) concluded, however, that this is

not indicative of an increase in the prevalence of LBP but rather of an increase in work loss, sick certification, compensation, and long-term disability awards.

Among industrialized nations, the United States has the highest rate of spinal surgery-five times that of Great Britain, for example (Taylor 1994). Studies examining the outcome of operative and non-operative treatment of back pain have not shown a distinct advantage for surgery. In Weber's (1983) prospective study of 280 patients with herniated nucleus pulposis diagnosed by myelography, the surgical group demonstrated a more rapid recovery than the non-operative treatment group.

At four years, however, the outcomes were roughly equivalent, and at ten years there were no appreciable differences in outcome.

Definitions and Common Terms

Acute Mechanical Low Back Pain

The pain is "mechanical"-that is, it varies with physicalactivity (e.g., prolonged sitting, bending forward) and with time. This pain is located in the lumbosacral region, The leg pain (unilateral) is described by the patient buttocks, and thighs, with no radiation to foot or toes. as worse than the back pain. Numbness and paresthesia (if present) are found in the same nerve root distribution.

Sciatica (Nerve Root Pain) Straight-leg raise (SLR) testing reproduces the leg pain.

Motor, sensory, or reflex changes are classically limited to

The term neroe root pain is preferable to the use of "scia single nerve root.

atica" because it more accurately describes the pathologic Thus, the term "sciatica," or nerve root pain, is used origin. Nerve root pain may arise from disc herniation, to describe leg pain that predominates in the distribution spinal stenosis, or postoperative scarring. Nerve root pain of a lumbosacral nerve root, with or without neurologic radiates down one leg in a dermatomal pattern. deficit.

Disc Herniation

Several studies have shown gradual l'esorption and disappearance of herniated discs on serial MRls withDisc herniation describes the protrusion of the gelatinous out surgical intervention. The larger disc herniations material of the disc (nucleus pulposus) through the annuwere

found to have had more resorption. This favorable natural history shows why up to 50% of patients with confirmed, painful herniated discs recover without surgery within 1 to 6 months.

Incidence of Low Back Pain

Mechanical LBP is very common, affecting between 70 and 85% of American adults at some point during theirlives. An estimated 1.3 billion days a year are lost from work in the United States because of LBP. Back pain complaints are second only to upper respiratory conditions as a cause of work absenteeism. Back pain is also the most common cause of disability in patients younger than 40 years. In 90% of patients, LBP resolves within 6 weeks (self·limited). In another 5% of patients, the pain re· solves by 12 weeks after initiation. Less than 1% of back pain is due to "serious" spinal disease (e.g., tumor, infection). Less than 1% of back pain stems from inflammatory

disease (rheumatologic work-up and treatment required).

Less than 5% of back pain is true nerve root pain. Most patients with LBP have one or more of four symptoms:

1. Back pain.

2. Leg pain.

3. Neurologic symptoms.

4. Spinal deformity.

Low Back Pain Evaluation

Diagnostic triage of back pain should be based primarily

on an accurate, focused clinical assessment (history and

physical examination) rather than the growing trend of

cursory examination and overreliance on imaging techniques.

Asymptomatic patients with no back pain have

been found to have a high incidence of "positive" MRI or

CT findings. Jensen and coworkers (1994) found that

64% of asymptomatic individuals who underwent an

MRI had "abnormal".appearing lumbar discs at some

level. Overreliance on the "shotgun approach" of diagno.

sis with a cursory examination and "knee-reflex" MRI

imaging will often obtain an incorrect diagnosis.

Because of the high incidence of false-positive results

on MRI (e.g., MRI reading a right-sided Ll-3 disc "herniation"

in a patient with mechanical LBP only), the

physician must correctly correlate the clinical symptoms

(right leg L5 sensory and motor changes) with the MRI

findings (right herniated disc at the L4-5 level).

"Abnormalities" seen on MRI or CT scan (e.g., agerelated

disc changes) often are not the origin for the patient's

back pain (i.e., these tests are highly sensitive, but

not specific). The crucial part of accurate diagnosis is the

physician's clinical findings and their correlation with

imaging findings.

We recommend that the primary care physician allow

the "back specialist" to order the MRI, CT, or myelogram

because different radiologic studies are employed for

different suspected clinical diagnosis (e.g., spinal stenosis

versus disc space infection versus herniated disc).

Risk Factors Previously Associated

with the Development of Low

Back Pain

Almost all of us (70 to 85%) will develop LBP at some

point. For this reason, it is inappropriate for physicians

to tell patients that LBP results from being obese, inac·

tive, or other factors.

Gordon Waddell's recommended text (1998) critically

reviews the poor methodology and science behind

studies that have described risks for LBP including:

• Heavy manual labor.

• Repetitive lifting and twisting.

• Postural stress.

• Whole body vibration.

• Monotonous work.

• Lack of personal control at work.

• Low job satisfaction.

• Poor physical fitness.

• Poor or inadequate trunk strength.

• Smoking.

Waddell, after critical review of these studies,

reached several interesting conclusions.

• Most people get back pain; heredity, gender, and

body build make little difference.

• It is good general health advice to stop smoking,

avoid or correct obesity, and get physically fit. These

may possibly help reduce the likelihood of developing

new episodes of back pain.

• Waddell asserts that "social class" is probably the

strongest personal predictor of incurring back trouble.

This is in part related to heavy manual labor and

in part to "social disadvantage."

"Social class" in Waddell's discussion reflects occupation

(manual rather than clerical labor) and social disadvantage

(e.g., poor medical care). The prevalence of back

pain appears to be slightly higher in those patients who

perform more manual types of labor. It is unclear which

particular aspect of work, social disadvantage (e.g., poor

medical care), lifestyle, attitudes, or behavior influences

this "social class" finding.

Back pain does have a greater impact on people in

heavy manual labor jobs. They are more likely to stay off

work and stay off longer than "clerical" laborers. This

may be a reflection of the effect of their back pain (i.e.,patient cannot lift the heavy loads required at work) or

may reflect the medical advice given to them by their

physicians (stay off work because of the possibility of aggravating

the back pain with resumption of heavy labor).

Classification of Low Back Pain Syndromes

Mechanical or Activity-related Causes

Segmental and discal degeneration

Myofascial or soft tissue injury/disorder/strain

Disc herniation with possible radiculopathy

Spinal instability with possible spondylolisthesis or fracture

Vertebral body fracture

Spinal canal or lateral recess stenosis

Arachnoiditis, including postoperative scarring

Spondylosis

Facet syndrome

Degenerative joint disease of spine

Systemic Disorders

Primary or metastatic neoplasm, including myeloma

Osseous, discal, or epidural infection

Inflammatory spondyloarthropathy

Metabolic bone disease, including osteoporosis

Vascular disorders such as atherosclerosis or vasculitis

Neurologic Syndromes

Myelopathy from intrinsic or extrinsic processes

Lumbosacral plexopathy, especially from diabetes

Neuropathy, including inflammatory demyelinating type

(e.g., Guillain-Barre)

Mononeuropathy, including causalgia

Myopathy, including myositis and metabolic causes

Referred Pain or Psychogenic Etiology

Gastrointestinal disorders

Genitourinary disorders, including nephrolithiasis, prostatitis,

and pyelonephritis

Gynecologic disorders, including ectopic pregnancy and

pelvic inflammatory disease

Abdominal aortic aneurysm

Hip pathology

Psychosocial causes

Compensable injury

Somatoform pain disorder

Psychiatric syndromes, including delusional pain

Drug seeking

Abusive relationships

Seeking disability or out-of-work status

Modified from Wheeler AH: Low back pain and sciatica. Am Fam

The examiner should evaluate and rule out potential

emergent causes of LBP during history and physical examination.

Careful history and review of systems may detect

nonmusculoskeletal origin of LBP. Our approach to

the work-up of LBP is to first rule out emergent or

nonmusculoskeletal causes of LBP. Once this is done,

the appropriate examinations and tests are performed to

confirm or rule out mechanical, nerve root, tumor, infectious,

traumatic, systemic, or inflammatory etiology.

Red Flags: Indicate Probable Serious Spinal

Pathology Requiring Active Work-up and

Evaluation of Back Pain

Red Flags

• Presentation age <20 yr or onset >55 yr (tumor?).

• Violent trauma, e.g. fall from a height, MVA (tumor?).

• Constant, progressive, nonmechanical pain.

• Thoracic pain.

• Previous history

• Carcinoma.

• Systemic steroids.

• Drug abuse, HIV.

• Systemically unwell

• Weight 1055.

• Persisting severe restriction of lumbar flexion.

• Widespread neurologic symptoms.

• Structural deformity.

• Positive studies

• ESR > 25.

• Plain x-ray: vertebral collapse or bone destruction.

Cauda Equina Syndrome and/or Widespread Neurologic

Disorder

• Difficulty with micturition/urinary retention.

• Loss of anal sphincter tone or fecal incontinence.

• Saddle anesthesia about the anus, perineum, or genitals

(numb).

• Widespread (>one nerve root) or progressive motor

weakness in the legs or gait disturbance.

• Sensory level.

Inflammatory Disorders (Ankylosing Spondylitis and

Related Disorders)

• Gradual onset before age 40 yr.

• Marked morning stiffness.

• Persisting limitation of spinal movements in all directions.

• Peripheral joint involvement.

• Iritis, skin rashes (psoriasis), colitis, urethral discharge.

MVA, motor vehicle accident.

From Waddell G: The Back Pain Revolution. New York, Churchill

Emergent Etiologies of Low Back Pain

Cauda Equina Syndrome

Emergent surgical decompression required.

Only entity affecting the lumbar spine that requires

emergent operative intervention.

Low incidence- « 1%).

Usual cause is extrinsic pressure on the cauda equina by

massive central herniated nucleus pulposus (HNP).

Other possible causes include:

• Epidural abscess.

• Epidural hematoma.

• Trauma.

• Epidural tumor.

Signs and symptoms include:

• Urinary retention

• May exhibit overflow incontinence.

• "Increased frequency."

• Saddle anesthesia

• Numbness In the distribution of the saddle (perineum,

anus, genitals).

• Bilateral sensory or motor deficits.

• Lumbar spine pain.

Requires emergent surgical intervention.

Ruptured Abdominal Aortic Aneurysm

• Pulsatile abdominal mass mayor may not be palpable

(50% of cases).

• Diminished pulses in the lower extremities.

• Unstable hemodynamically.

• Usually older than 50 yr.

• Requires immediate vascular surgery consultation and

dramatic cardiovascular rescue/stabilization.

Fracture of lumbar Spine

• High-velocity trauma (e.g., motor vehicle accident) is the

typical mechanism.

• Requires immobilization and workup by orthopaedic surgeon/

neurosurgery trauma team and appropriate shortterm

and long-term spine stabilization.

• See a spinal fracture text for further review.

Epidural Abscess

• Symptoms usually progress within a week.

• Spinal pain with fever.

• Nerve root pain.

• Weakness.

• Paralysis.

• Central nervous system signs.

• Sepsis.

Predictors

Predictors of Return,to,Work Status of

Patients with Back Pain (Chronicity)

Cats-Barril and Frymoyer (1991) followed 250 patients to

evaluate which of numerous factors best predicted who

was still off work (no return to work) after 6 months.

They found the best predictors, in order of decreasing

accuracy, were

1. Job characteristics: work history, occupation,

job satisfaction, satisfaction with policies and

benefits.

2. Patient beliefs about whether back pain was compensable,

party at fault, and legal involvement (social

factors).

3. Past hospitalization for back pain.

4. Educational level.

Workplace and social factors were by far the most

powerful influences on chronicity (84% accurate in

predicting who will be chronically disabled). These were

more predictive than type of injury, health behavior, or

other factors.

Risk Factors for Chronicity of Low Back Pain

• Previous history of LBP

• Significant work loss (due to LBP) in past year

• low job satisfaction

• Adversarial medicolegal proceedings

• Radiating leg pain

• Reduced SLR (positive test)

• Signs of nerve root involvement

• Reduced trunk muscle strength and endurance

• Poor physicaI fitness

• Self-rated poor health

• Heavy smoking

• Psychological distress and depressive symptoms

• Disproportionate illness behavior

• Personal problems-alcohol, marital, financial

Low educational attainment and heavy physical occupation

slightly increase the risk of LBP and chronicity but markedly

increase the difficulty of rehabilitation and job retraining.

Evaluation of Patients with Low

Back Pain

A thorough history and examination allows an accurate

~orking diagnosis to be made in 90% of patients with

LBP.

Be wary of constant pain unrelated to activity

or position, nocturnal pain, pain refractory to treatment,

or concomitant constitutional symptoms (Table

9-1).

Tension Tests

Straight-Leg Raises Test (see Fig. 9 - 5)

.ALR stretches the L5 and S1 nerve roots. Therefore,

-a~ abnormal SLR suggests pathology of the L5 or S 1

nerve root. The sciatic nerve runs down the posterior

thigh and is formed by L4, L5, Sl, 52, and S3

nerve roots.

• This test is done with the patient lying comfortably

flat. The leg is slowly elevated with the knee in full

extension (straight). In normal patients, some hamstring

tightness will be felt at 80 to 90 degrees of hip

flexion.

• In the presence of sciatica or nerve root

irritation, the patient complains of shooting pain

Lasegue Test (see Fig. 9-6)

• This test is an adjunct to the SLR. When the patient

complains of reproduction of sciatic pain with an

SLR, the examiner passively dorsiflexes the foot of

the leg being raised. If this dorsiflexion worsens the

sciatica, the Lasegue test is positive.

Crossed Straight-Leg Raises Test (see Fig. 9- 7)

• The examiner performs an SLR test on the leg opposite

to that with the sciatica. If this is positive

(e.g., an uninvolved left leg SLR produces the rightsided

sciatica), the result is very sensitive and specific

for a herniated L5 -S1 or L4-5 lumbar disc.

Figure 9-9. Slump test.

Figure 9-10. Femoral nerve stretch test.

Bowstring Sign (see Fig. 9-8)

• The examiner starts the test by performing an SLR

test until the radicular pain is produced. The knee is

then flexed to 90 degrees, typically relieving the patient's

symptoms. The examiner then places pressure

with the fingers over the posterior aspect of the sciatic

nerve in the popliteal fossa. If this reproduces

the pain, sciatica is confirmed.

SLump Test (see Fig. 9-9)

• This is a variant of the SLR test and Lasegue test,

designed to place tension across the sciatic nerve

roots.

• The patient, initially sitting erect, is encouraged to

slump forward and then fully forward flex the cervical

spine.

• At the same time, the patient performs an SLR.

• The patient then dorsiflexes this same foot (duplicating

the Lasegue sign). Repeat for each leg. Reproduction

of the radicular pain during these maneuvers

is very suggestive of sciatic nerve root

tension.

Femoral Nerve Stretch Test (see Fig. 9-10)

• The femoral nerve stretch test is designed to compress

the L2, L3, or J4 nerve roots. Compression of

these upper lumbar roots is not common.

• The patient is positioned prone on the table with the

knee flexed to at least 90 degrees. The examiner

then passively extends the hip by lifting the thigh off

the examination table. A positive test reproduces the

570 Clinical Orthopaedic Rehabilitation

patient's radicular pain in the anterior thigh, rather

than a mild feeling of tightness.

Rectal Examination (Sphincter Tone)

Five signs that suggest nonorganic pathology (Wag'/

dell sigll§) -~

1. Superficial or nonanatomic tenderness to palpation

• Patient reports disproportionate pain to extremely

light touch, or tenderness that does correlate

with anatomic structures.

2. Simulation sign

• Axial compression of the head or rotational simulation

maneuver (similar to a standing logroll

with no true rotation of the affected area) elicits

"pain" despite no actual provocation.

3. Distraction sign

• The same test {e.g., SLR supine versus sitting

[Fig. 9-ll]} performed on the "distracted" patient

does not cause pain, unlike when performed

on the patient initially and was "very

painful."

4. Regional sensory or motor disturbance

• A nonanatomic distribution of abnormal sensation

(e.g., the entire leg) is reported rather than

an anatomic, dermatomal distribution of pain or

numbness.

5. Overreaction

• Patient verbally or physically reacts in an inappropriate,

theatrical manner to light touch or

gentle examination.

Other Important Areas That Should Be

Examined Simultaneously

• Hip{s) {internal and external rotation testing of the

hip to rule out intra-articular arthritic involvemend-

pain produced on internal or external rota-

Figure 9-11. Distraction sign.

tion of the hip is more indicative of intra-articular

hip pathology rather than back origin.

• SI joints (FABER maneuver and palpation of the SI

joints to rule out sacroiliitis).

• Abdominal examination (e.g., rule out gallbladder,

aortic aneurysm).

• Pulses of lower extremities (rule out vascular claudication).

• Sacrum (fracture, tumor).

• Coccyx (rule out coccydynia).

• Lymph nodes (rule out lymphadenopathy associated

with sexually transmitted diseases [STDsJ, infection,

rumor).

• Genitalia or meatus or vaginal discharge (STDs).

Figures 9-12 to 9-14 and Tables 9-4 and 9-5 illustrate

lumbar disc levels, neurologic levels, and associated

motor, sensory, and reflex findings.

We also employ the single-leg hyperextension test

(stork test, Fig. 9-15) to evaluate for possible spondylolysis

in children performing repetitive spine flexion and ex