Guidelines—Ann IM 2007;147:478; Nejm 2001;344:363; Ann IM 1990;112:598

Cause:Ruptured herniated intervertebral disc; musculoligamentous strains/trauma; osteoarthritis of facet joints; perhaps leg length discrepancies; in elderly, vertebral compression fractures

Pathophys:Myofascial, skeletal, disc, and/or ligamentous entrapment/compression of nerve conduction/vascular flow causing secondary edema, spasm and contracture, and/or neurosensory hyperstimulation or deficits

65% of the population have low-back sx sometime in life; M = F; onset age 30-50 yr

Sx:Focal (segmental) pain distal radiation of burning/shooting pain and/or paresthesias, often worsened by cough; decr range of motion due to pain and/or muscular restriction

(see Diagnostic Algorithm for low Back Pain Syndromes)

Si:rv of exam (Bull Rheum Dis 1983;33:4)

Straight leg raising <60° on affected side induces sx; if SLR on opposite side induces, this positive “crossed-leg sign” is highly specific for central disc rupture

Levels: Depression or loss of knee jerk = L_3-4 (L₄ root); ankle jerk = L₅-S₁ (S₁ root); toe extensors, esp extensor hallucis longus (big toe extensor), and sensation loss medial foot, esp between 1st and 2nd toes = L_4-5 (L₅ root)

Most (>90%) improve with conservative rx over several days-weeks, and no workup is required unless motor loss present and does not improve or worsens over this time period. 2/3 recur within 1 yr; pain lasts 2 mo on average (Spine 1993;18:1388)

Workman’s compensation (Ann IM 1978;89:992); cauda equina syndrome w rectal or bladder dysfunction

r/o SPINAL STENOSIS (Nejm 2008;358:794, 818; 2007;356:1241, 2257): prevalent in elderly, usually over 50 yr, esp over 65 yr. Caused by spondylolisthesis. Sx of pain, pseudoclaudication, numbness, worse with hips extended, eg, walking downhill; unlike vascular claudication, no pain in calf or foot and not predictably induced by walking a distance; bilateral in 2/3. Rx is surgical; but many can be managed with PT, with which sx tend to improve; beware excessive fusions (Jama 2010;303:71)

Xray:MRI/CT good if observed abnormality correlates with sx and si, but 1/3 of CTs interpreted as abnormal (Spine 1984;9:549); and, in normal asx people, bulges (50%) and protrusions (25%) are present on MRI (Jama 2010;303:71, Nejm 1994;301:69). Initial plain films adequate (Jama 2003;289:2810)

Scanograms for leg length are the only way to measure but rarely needed; tapes are inaccurate (Spine 1983;8:643)

Rx: (guidelines—Ann IM 2007;147:492, 505)

(see Diagnostic Algorithm for low Back Pain Syndromes)

Prevention: exercise programs w aerobic conditioning and leg/back strenghthening helps; back belts no help (Jama 2000;284:2727)

Primary care strategy (Ann IM 1994;121:187), 70% better by 1 mo:

• Educate re chronic/recurrent nature but that severe flareups are time-limited
• Pain rx only as time-limited, scheduled regimens, not prn; limited (<2 d) bed rest
• Referral for surgical evaluation only for abnormal neurologic findings
• Graded increasing activity even if pain not better/resolved

Education and/or lumbar supports of questionable value (Jama 1998;279:1789)

Bed rest: even 2 d bed rest slows recovery as do exercises, best strategy is cont’d normal activity as tolerated (Nejm 1995;332:351), true even if have sciatic sx (Nejm 1999;340:418); hard bed/bed board not helpful? (Lancet 2003;362:1599)

NSAIDs; tricyclics, tetracyclics; heat; massage; muscle strengthening and flexibility exercises as well as a progressive fitness program (BMJ 1995;310:151); manipulation probably speeds recovery of acute and subacute types by 10-20% (RAND meta-analysis—Ann IM 1992;117:590); short-acting opiods for limited time periods. But exercise rx of acute pain is no help (Spine 1993;18:1388) but is helpful when chronic (>4 wk) (BMJ 1999;319:279). Steroid injections no help (Nejm 1997;336:1634; 1991;325:1002). TENS no help in chronic back pain (ACP J Club 2001;135:99)

Manipulative techiques if not better in 3 wk, including high velocity low amplitude, strain/counterstrain, and craniosacral; chiropractic or PT care of acute low-back pain is more expensive though more satisfying for pt w same result as primary care doc care (meta-analysis—Ann IM 2003;138:871; Nejm 1998;339:1021; 1995;333:913). Accupuncture similarly helpful (Ann IM 2005;142:651)

Heat

Surgery if worsening motor weakness after 2 wk; recovery faster and pain less if operate at 8-14 wk after onset rather than 24+ wk later (Nejm 2007;356:2245), but long term, the latter comes out the same if combined with medical rx (Jama 2006;296:2441, 2451, 2483, 2485)

of chronic low-back pain: transcutaneous electrical nerve stimulator (TENS) 30 min tiw × 3 wk helps (Jama 1999;281:818); magnets no help (Jama 2000;283:1322); multidisciplinary pain center referral; opioids not that helpful