9.06 Acute Lumbar Strain
========================

("Mechanical" Low Back Pain, Sacroiliac Dysfunction)

agk's Library of Common Simple Emergencies

Presentation
------------

Suddenly or gradually after lifting, sneezing, 
bending, or other movement the patient develops 
a steady pain in one or both sides of the lower 
back. At times, this pain can be severe and 
incapacitating. It is usually better on lying 
down, worse with movement, and will perhaps 
radiate around the abdomen or down the thigh, 
but no farther. There is insufficient trauma to 
suspect bony injury (e.g., a fall or direct 
blow); and no evidence of systemic disease 
which would make bony pathology likely (e.g., 
osteoporosis, metastatic carcinoma, multiple 
myeloma). On physical examination, there may be 
spasm (i.e., contraction which does not relax, 
even when the patient is supine or when the 
opposing muscle groups contract, as with 
walking in place) in the paraspinous muscles; 
but there is no point tenderness over the 
spinous processes of lumbar vertebrae and no 
nerve root signs such as pain or paresthesia in 
dermatomes below the knee (especially with 
straight leg raising), foot weakness, or loss 
of the ankle jerk. There may be point tender- 
ness to firm palpation or percussion over the 
sacroiliac joint, especially if the pain is on 
that side.

What to do:
-----------

- Perform a complete history and physical exam- 
    ination of the abdomen, back, and legs, 
    looking for alternative causes for the back 
    pain.
- Consider plain x-rays of the lumbosacral 
    spine of those who have suffered injury 
    sufficient to cause bony injury, patients 
    under the age of 20 or over 50 who have had 
    pain more than a month, and patients who 
    are on long term corticosteroid medication 
    or have a history of cancer.
- Order an erythrocyte sedimentation rate (ESR) 
    on patients with a history of cancer or 
    intravenous drug abuse or signs or symptoms 
    of underlying systemic disease (e.g., 
    unexplained weight loss, fatigue, night 
    sweats, fever, lymphadenopathy, and back 
    pain at night or unrelieved by bed rest).
- For point tenderness over a sacroiliac joint 
    with no neurologic findings to suggest 
    nerve root compression, try an intra- 
    articular injection of a local anesthetic 
    mixed with a corticosteroid. Improvement of 
    pain is both diagnostic and therapeutic. 
    Draw up 10 mL of 0.5% bupivacaine 
    (Marcaine, Sensorcaine) mixed with 1 mL (40 
    mg) of methylprednisolone (DepoMedrol) or 
    1-2 mL (6-12 mg) of betamethasone 
    (Celestone, Soluspan). Using a 1.5" 25 
    gauge needle and sterile technique, inject 
    deeply into the sacroiliac joint at the 
    point of maximal tenderness or into the 
    dimple immediately lateral to the sacrum. 
    When the needle is in the joint there 
    should be a free flow of medication from 
    the syringe without causing soft tissue 
    swelling. During the injection, the patient 
    may feel a brief increase of pain, followed 
    by dramatic relief in 5-20 minutes which is 
    usually permanent.
- For point tenderness of the lumbosacral 
    muscles, inject 10-20 mL of 0.25-0.5% 
    bupivicaine (Marcaine, Sensorcaine) deeply 
    into the points of maximal tenderness of 
    the erector spinae and quadratus lumborum 
    muscles, using a 1.5-3.5" 25 gauge needle. 
    Quickly puncture the skin, drive the needle 
    into the muscle belly and inject the 
    anesthetic, slowly advancing or withdraw- 
    ing, fanning out the medication. Often one 
    fan block can reduce symptoms by 95% after 
    injection and yield a 75% permanent 
    reduction of painful spasms. Following 
    injection, teach stretching exercises.
- For severe pain that cannot be relieved by 
    injections of local anesthetic, it may be 
    necessary to provide the patient with one 
    to two days of bed rest, although the 
    majority of patients with acute low back 
    pain recover more rapidly with continuing 
    ordinary activities within the limits 
    permitted by their pain than with bed rest 
    or back-mobilizing exercises.
- Consider disk herniation when leg pain 
    overshadows the back pain. Back pain may 
    subside as leg pain worsens. Look for 
    weakness of ankle or great toe dorsiflexion 
    and sensory changes over the medial dorsal 
    foot with compression of the fifth lumbar 
    nerve root or weak plantarflexion, 
    diminished ankle reflex and paresthesias of 
    the lateral foot with the first sacral 
    root. Raise each leg thirty degrees from 
    the horizontal and consider the test 
    positive for nerve root compression if it 
    produces pain down the leg along a nerve 
    root distribution rather than pain in the 
    back, increased by dorsiflexion of the 
    ankle and relieved by plantarflexion. 
    Ipsilateral straight leg raising is a 
    moderatively sensitive but not a specific 
    test--a herniated intervertebral disk is 
    more strongly indicated when radicular pain 
    is reproduced in one leg by raising the 
    opposite leg. Prescribe short term bed rest 
    and non-steroidal anti-inflammatory 
    analgesics and arrange for general medical, 
    orthopedic or neurosurgical referral. Some 
    consultants recommend short term cortico- 
    steroid treatment such as prednisone 50 mg 
    qd x5 days. The patient shound try four to 
    six weeks of conservative treatment before 
    submitting to an operation on the herniated 
    disk. Eighty per cent of patients with 
    sciatica recover with or without surgery. 
    The rare cauda equina syndrome is the only 
    complication of lumbar disk herniation that 
    calls for emergent surgical referral. It 
    occurs when a massive extrusion of disk 
    nucleus compresses the caudal sac contain- 
    ing lumbar and sacral nerve roots, produc- 
    ing bilateral radicular leg pain or weak- 
    ness, bladder or bowel dysfunction, perin- 
    eal or perianal anesthesia, decreased 
    rectal sphincter tone in 60-80% and urinary 
    retention in 90%.
- Prescribe a short course of anti-inflammatory 
    analgesics (aspirin, ibuprofen, naprosyn) 
    for patients who are not already taking 
    NSAIDs. Because gastric bleeding and renal 
    insufficiency are common with long-term use 
    of NSAIDs, consider substituting 
    acetaminophen or salsalate.
- Prescribe ice to the acutely injured area, 20 
    minutes per hour for the first day . (This 
    therapy is unconventional, but works as 
    well as it does for any other musculoskel- 
    etal injury.)
- Refer patients with uncomplicated back pain 
    to their primary care provider for follow 
    up care in three to seven days. Reassure 
    them that back pain is seldom disabling and 
    that it usually resolves with their return 
    to normal activity. Tell them that 
    cigarette smoking, sedentary activity and 
    obesity are risk factors for back pain. 
    Teach them to avoid twisting and bending 
    when lifting and show them how to lift with 
    the back vertical, using thigh muscles and 
    holding heavy objects close to the chest, 
    to avoid re-injury.

What not to do:
---------------

- Do not be eager to use narcotic pain 
    medicines. The sensation of pain from an 
    acute musculoskeletal injury reminds the 
    patient not to use the damaged part and 
    exacerbate the injury, but instead to keep 
    it at rest and speed healing. Narcotics are 
    also apt to make the patient constipated, 
    and straining at stool can be especially 
    uncomfortable with a back injury.
- Do not be too eager to use anti-spasm 
    medicines. Many have sedative or 
    anticholinergic side effects.
- Do not apply lumbar traction. It has not been 
    proven any better than placebo for 
    relieving back pain.

Discussion
----------

Low back pain is a common and sometimes chronic 
problem which accounts for an enormous amount 
of disability and time lost from work. The 
approach discussed above is geared only to the 
management of acute injuries and flareups, from 
which most people recover on their own, only 
about 10% developing chronic problems. With 
acute pain, reassurance plus limited medication 
may be the most useful intervention.

History and physical examination are essential 
to rule out serious pathologic conditions which 
can present as low back pain but which require 
quite different treatment--aortic aneurysm, 
pyelonephritis, pancreatitis, pelvic 
inflammatory disease, ectopic pregnancy, 
retroperitoneal or epidural abscess.

The standard five-view x-ray study of the 
lumbosacral spine may entail 500 mrem and only 
1 in 2500 lumbar spine plain films of adults 
below age 50 show an unexpected abnormality. In 
fact, many radiographic anomalies such as spina 
bifida occulta, single-disk narrowing, spondyl- 
osis, facet joint abnormalities and several 
congenital anomalies are equally common in 
symptomatic and asymptomatic individuals. It is 
estimated that the gonadal dose of radiation 
absorbed from a five-view lumbosacral series is 
equivalent to that from six years of daily 
anterioposterior and lateral chest films. The 
World Health Organization now recommends that 
oblique views be reserved for problems 
remaining after review of AP and lateral films. 
For simple cases of low back pain, even with 
radicular findings, both CT and MRI are overly 
sensitive and often reveal anatomic abnormal- 
ities that have no clinical significance.

While adults are more apt to have disk 
abnormalities, muscle strain and degenerative 
changes associated with low back pain, 
athletically active adolescents are more likely 
to have posterior element derangements like 
stress fractures of the pars interarticularis. 
Early recognition of this spondylolysis and 
treatment by bracing and limitation of activity 
may prevent nonunion, persistant pain and 
disability.

Malingering and drug seeking are major 
psychological components to consider in 
patients who have frequent ED visits for back 
pain and whose responses seem overly dramatic 
of otherwise inappropriate. These patients may 
move around with little difficulty when they do 
not know they are being observed. They may 
complain of generalized superficial tenderness 
when you lightly pinch the skin over the 
affected lumbar area. If you are suspicious 
that the patient's pain is psychosomatic or 
nonorganic you can use the axial loading test, 
in which you gently press down on the head of 
the standing patient. This should not cause 
significant musculoskeletal back pain. You can 
also perform the rotation test, in which the 
patient stands with his arms at his sides. Hold 
his wrists next to his hips and turn his body 
from side to side, passively rotating his 
shoulders, trunk and pelvis as a unit. This 
maneuver creates the illusion that you are 
testing spinal rotation, but in fact you have 
not altered the spinal axis and any complainst 
of back pain should be suspect.

References
----------

- Deyo RA, Diehl AK, Rosenthal M: How many days 
    of bed rest for acute low back pain? *N Eng 
    J Med* 1986;315:1064-1070.
- Deyo RA, Rainville J, Kent DL: What can the 
    history and physical examination tell us 
    about low back pain? *J Am Med Assoc* 
    1992;268:760-765.
- Malmivaara A, Hakkinen U, Aro T et al: The 
    treatment of acute low back pain: bed rest, 
    exercise, or ordinary activity? *N Eng J 
    Med* 1995;332:351-355.
- Carey TS, Garrett J, Jackman A et al: The 
    outcomes and costs of care for acute low 
    back pain among patients seen by primary 
    care practitioners, chiropracters and 
    orthopedic surgeons. *N Eng J Med* 
    1995;333:913-917.
- Elam KC, Cherkin DC, Deyo RA: How emergency 
    physicians approach low back pain: choosing 
    costly options. *J Emerg Med* 1995; 
    13:143-150.

 ----------------------------------------------------
 from Buttaravoli & Stair: COMMON SIMPLE EMERGENCIES
 Longwood Information LLC 4822 Quebec St NW Wash DC
 1.202.237.0971 fax 1.202.244.8393 electra@clark.net
 ----------------------------------------------------