Low Back Pain
Introduction
Low back problems affect virtually everyone at some time during their
life. The prevalence in working-age adults is 50 percent with 10-20 percent of these
seeking medical care. It is a common presenting complaint to the GMO and perhaps the most
common cause of lost productivity. Low back pain is the most common cause of disability
for those under age 45. For this reason it is imperative that the GMO be competent in
assessing and treating low back pain.
This chapter will focus on acute low back pain, which will be defined as activity
intolerance due to lower back or back related leg symptoms of less than 3 months duration.
Nearly 90 percent of patients spontaneously recover from low back pain symptoms and resume
normal daily activities within 3 months.
Initial Assessment
A focused medical history and physical examination are sufficient to assess the patient
with acute or recurrent limitations due to low back symptoms less than 4 weeks of
duration. A "red flag" is defined as a debilitating condition or disease that
should be considered in the work-up of every patient.
Red Flags
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Fractures.
Major trauma such as vehicle accident, aircraft mishap, or fall from height.
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Possible tumor or Infection. Look for any history of cancer. Constitutional symptoms can include recent fever, chills,
or unexplained weight loss. Look for a source of an infection, such as urinary tract
infection, IV drug abuse, or immune suppression (steroids, positive HIV). A pattern of
worsening back pain at night, worse when supine. (Note: spinal cancer is less likely in
active duty age range).
-
Possible Cauda Equina Syndrome. Evaluate for saddle anesthesia, bladder dysfunction, such as urinary retention, increased
frequency, or overflow incontinence. Also assess for a severe or progressive neurologic
deficit in the lower extremities.
Acute low back symptoms
Symptoms can then be classified into one of three working categories:
-
Potentially serious spinal conditions - tumor, infection, spinal fracture,
decompression sickness (Type I), or a major neurologic compromise, such a cauda equina
syndrome.
-
Sciatica. Back related lower limb symptoms suggesting lumbosacral nerve root
compromise or compression.
-
Nonspecific back symptoms. These occur primarily in the back and suggesting
neither nerve root compromise nor a serious underlying condition.
Medical History
These questions are directed primarily at activity tolerance, not pain.
-
What are your symptoms? Do you have pain, numbness, weakness, stiffness, onset acute or
gradual?
-
Location? - primarily in back, leg, or both?
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How do these symptoms limit you? How long can you sit, stand, and walk? How much weight
can you lift?
-
When did the current limitations begin and how long have your activities been limited?
(More than 4 weeks?) Have you had similar episodes previously? Have you had any previous
testing or treatment?
-
What do you hope we can accomplish during this visit?
Physical Examination
The physical examination should include:
Addressing Red Flags
Physical examination evidence of severe neurologic compromise that correlates with
the medical history may indicate a need for immediate consultation. The examination may
further modify suspicions of tumor, infection, or significant trauma. A medical history
suggestive of nonspinal pathology mimicking a back problem may warrant examination of the
chest, abdomen, pelvis, pulses, or other areas.
Observation and Regional Back Examination
Check for limping; guarding of lumbar motion (guarding in all plains may suggest
spinal infection); vertebral point tenderness (this may suggest fracture or infection).
Neurologic Screening
Identify any nerve root impairment, peripheral neuropathy or spinal cord dysfunction.
Remember that over 90 percent of all clinically significant, lower extremity
radiculopathies due to disc herniation involve either the L5 or S1 nerve root at the L4-L5
or L5-S1 discs level.
Clinical tests for sciatic tension
The straight leg raising (SLR) test produces leg pain by stretching the L5 and/or
S1 nerve roots. Performance testing involves having the patient lie in a supine position.
Place your hand over the anterior thigh and your other hand beneath the heel. Be certain
that the leg is straight and ask the patient to relax. Gradually raise the leg at the heel
while keeping the knee extended and allowing for simultaneous flexion of the hip. Ask the
patient to state when the symptoms occur. Ask where the pain is felt and where the most
distal area of discomfort is located (back, hip, thigh, knee, or below the knee). Pain
below the knee at less than 70 degrees of straight leg raising, aggravated by dorsiflexion
of the ankle and relieved by ankle planter flexion or external limb rotation, is most
suggestive of tension on the L5 or S1 nerve root related to disc herniation. Reproducing
back pain alone with SLR testing does not indicate significant nerve root tension.
Crossover pain
Pain is elicited in the affected leg (sciatica) while the well limb is straight leg
raised. Crossover pain is a stronger indication of nerve root compression than pain
elicited from "straight leg raising" (SLR) the painful limb.
Sitting knee extension
This is also used to test for sciatic tension. The patient with significant nerve
root irritation tends to complain or lean backward in order to reduce tension on the
nerve. While the patient is sitting on the table with both hips and knees are flexed at 90
degrees, slowly extend the knee as if evaluating the patella or bottom of the foot. This
maneuver stretches nerve roots as much as a moderate degree of supine SLR.
Initial Care Patient Education
Back education will vary from patient to patient. If no red flags are discovered
during the initial assessment, reassure the patient that no dangerous problems have been
found and that a rapid recovery can be expected. If the patient does not recover in
several weeks, a repeat medical evaluation including special studies should be
recommended. Also review the type of treatment and activities that the patient has
followed since the last visit.
Patient comfort
The vast majority of patients will obtain adequate comfort with a prudent
restriction of activities and non-prescription analgesics.
Medications
The safest effective medication is for pain relief is acetaminophen. NSAIDs
including aspirin and Ibuprofen, are also effective but may cause gastrointestinal
irritation / ulceration or (less commonly) renal or allergic problems. Acetaminophen
may
also be used safely in combination with NSAIDs. Muscle relaxants are no more effective
than NSAIDs either by themselves or in combination with NSAIDs. Remember muscle relaxants
cause drowsiness. Opioids should be avoided whenever possible. If prescribed, these should
be given for only a short period of time. Poor patient tolerance, risk of drowsiness,
decreased reaction time, clouded judgment, and potential misuse are reasons not to
prescribe narcotics. Patients should be warned about these potentially debilitating
problems.
Physical Methods
Activity Alteration
To avoid both undue back irritation and debilitation from inactivity,
recommendations for alternate activity can be helpful. Most patients will not require bed
rest. Prolonged bed rest (more than 4 days) has potential debilitating effects, and the
efficacy in the treatment of acute low back problems is unproven. Two to four days of bed
rest are reserved for patients with the most severe limitations (due primarily to leg
pain).
Avoiding undue back irritation
Activities and improper posture can aggravate back symptoms. Patients limited by
back symptoms can minimize the stress of lifting by keeping any lifted object close to the
body at the level of the navel. Twisting, bending, and reaching while lifting also
increases stress on the back. Sitting may aggravate symptoms for some patients as well.
Advise patients to avoid prolonged sitting and to change position often. A soft support
placed at the small of the back, armrests to support some bodyweight, and a slight recline
of the chair back may make required sitting more comfortable.
Avoiding debilitation
Until the patient returns to normal activity, aerobic (endurance) conditioning exercise
such as walking, stationary biking, swimming, and even light jogging may be recommended to
avoid debilitation from inactivity. An incremental, gradually increasing regimen of
aerobic exercise (up to 20-30 minutes daily) can usually be started within the first 2
weeks after symptoms have resolved. Such activities have been found to stress the back no
more than sitting for an equal period of time on the side of a bed. Patients should be
informed that exercise might increase symptoms slightly at first. If intolerable, some
exercise alteration is usually helpful.
-
Specific conditioning exercises for trunk muscles are more mechanically stressful to the
back than aerobic exercise. Such exercises are not recommended during the first few weeks
of symptoms, although they may later help patients regain and maintain activity tolerance.
-
There is no evidence to indicate that back-specific exercise machines are effective for
treating acute low back problems. Neither is there evidence that stretching of the back
helps patients with acute symptoms.
Sitting and unassisted lifting
When prescribing work restrictions, remember that even moderately heavy unassisted
lifting may aggravate back symptoms. Restrictions are intended to allow for improvements
in recovery time. Restrictions should only be for a short period of time, and should never
exceed 3 months since no benefit is apparent after 3 months.
Recommendations for sitting
periods and weight lifting
-
Employees without low back symptoms should not sit for more than 50 minutes without
getting a break to get up and walk around.
-
Employees with mild pain should not sit more than 30 minutes
-
Employees with moderate pain should not sit for more than 20 minutes.
-
Workers without back symptoms should not routinely be lifting more than 80 pounds (men)
and 40 pounds (women).
-
Workers with severe or moderate symptoms should not lift more than 20 pounds.
-
Workers with mild symptoms should not lift more than 60 pounds (men) and 35 pounds
(women).
Special studies and diagnostic considerations
Routine testing (laboratory tests, plain x-rays of the lumbosacral spine) and
imaging studies are not recommended during the first month of activity limitation due to
back symptoms except when significant trauma or other "red flag(s) " are
present; then selected studies are appropriate, as is referral to a specialist.
Summary
The overall plan for otherwise healthy Navy members with acute low back symptoms should
include the following guidelines:
-
a competent and thoroughly documented evaluation.
-
optimism that a full recovery is likely.
-
pain control with mild analgesic medications.
-
early return to modified work.
-
appropriate work activity restrictions.
-
a progressive program of exercise and escalating activity tolerance.
In the absence of red flags or severe neurological compromise, few patients should be
at complete bed rest.
Reference
-
Agency for Health Care Policy and Research, Acute Low Back Pain problems in Adults,
Clinical Guide and Quick Reference Guide #14, website address: (http://www.ahcpr.gov/).
Reviewed by CAPT John S. Webster, MC, USN, Chairman, Orthopedic Department, Residency
Program Director, Naval Medical Center San Diego, and LCDR Geoffrey McCullen, MC, USNR,
Director, Orthopedic Spine Service, Naval Medical Center San Diego, San Diego, CA (1999).
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Preface
· Administrative Section
· Clinical Section
The
General Medical Officer Manual , NAVMEDPUB 5134, January 1, 2000
Bureau
of Medicine and Surgery, Department of the Navy, 2300 E Street NW, Washington, D.C.,
20372-5300
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