Page 221 Guide to Pain Management in Low-Resource Settings

Chronic Nonspecifi c Back Pain 209

Why is the “6-week rule” is When is periodic back pain
so important? “normal” and chronic back pain
“not normal”?
Most normal connective tissues heal within 6–12 weeks
unless instability or malignant or infl ammatory tissue Th e lumbar spine can support heavy loads in relationship
destruction is present. Th erefore, in any prolonged back to its cross-sectional area. It resists anterior gravitational
pain, these pain etiologies should be ruled out. Pain that movement by maintaining lordosis in a neutral posture.
radiates to the legs in a radicular pattern should be thor- Unlike the thoracic spine, the lumbar spine is unsupport-
oughly investigated, especially if sensory or motor defi - ed laterally. Th e intervertebral disks are composed of the
cits are noted in the patient. outer annulus fi brosis and the inner nucleus pulposus.
Th e outer portion of the annulus inserts into the verte-
If the pain etiologies mentioned bral body and accommodates nociceptors and proprio-
above are ruled out and the back ceptive nerve endings. Th e inner portion of the annulus
pain persists, how should the pain encapsulates the nucleus, providing the disk with extra
strength during compression.
should be interpreted?
Th e nucleus pulposus of a healthy interverte-
bral disk constitutes two-thirds of the surface area of
Overinterpretation of CT or MRI fi ndings should be
avoided. Although disk protrusions have been popular- the disk and supports more than 70% of the compres-
sive load. Until the third decade of life, the gel of the in-
ized as causes of LBP, asymptomatic disk herniations on
CT and MRI are common even in young adults. Fur- ner nucleus pulposus is composed of approximately 90%
water; however, the water content gradually diminishes
thermore, there is no clear relationship between the ex-
tent of disk protrusions and the degree of clinical symp- over the next four decades to approximately 65%. Until
the third decade of life, approximately 85% of the weight
toms. Th erefore, other causes for persistent LBP have to
be taken into consideration. If diagnostic studies reveal is transmitted across the disk. However, as disk height
decreases and the biomechanical axis of loading shifts
no structural cause, physicians and patients alike should
question whether the pain has a psychosomatic, rather posteriorly, the posterior articulations (facet joints) bear
a greater percentage of the weight distribution. Bone
than purely somatic, cause. Physical and nonphysical
factors, interwoven in a complex fashion, infl uence the growth compensates for this increased biomechanical
stress to stabilize the trijoint complex.
transition from acute to chronic LBP. Th e identifi cation
of all contributing physical and nonphysical factors en- Th erefore, to some extent, hypertrophy of the
facets and bony overgrowth of the vertebral endplates
ables the physician to design a comprehensive approach
with the best likelihood for success. constitute a normal physiological reaction to the age-de-
pendent degeneration of the disks to stabilize the spine.
Only in patients with inadequate “self-stabilization” do
Is low back pain a these changes contribute to progressive foraminal and
worldwide problem? central canal narrowing. Spinal stenosis reaches a peak
later in life and may produce radicular, myelopathic, or
Disability because of LBP has reached endemic propor-
vascular syndromes such as pseudoclaudication and
tions, with enormous socioeconomic consequences, in
spinal cord ischemia. LBP is most common in the early
industrialized societies. Studies indicate that the preva-
stages of disk degeneration and “self-stabilization.”
lence of LBP is not as dependent on genetic factors that
could predispose persons of specifi c ethnicity or race to
this disorder. Men and women are aff ected equally. But What types of pain
lifestyle may be one of the most important predisposing may be identifi ed?
factors for LBP. Th erefore, LBP is starting to become a
major health care problem in all countries in which eco- Specifi c pain
nomic and cultural changes are transforming their soci- Back pain that lasts longer than 3 weeks with major
eties to modern industrialized societies for the benefi t functional impairment should be thoroughly evaluated
of their citizens. to identify serious causes, especially malignant diseases