Low Back Pain – McMaster2009

Low Back Pain

  • Acute <6wk, subacute 6-12wk, chronic >12wk
  • Lifetime prevalence: 90% & 90% resolved in 6wk, <5% become chronic
  • Peak prevalence: 45-60yo
  • Most common cause of chronic disability in <45yo

1) In a patient with undefined acute low-back pain (LBP):
a) Rule out serious causes (e.g., cauda equina syndrome, pyelonephritis, ruptured abdominal aortic aneurysm, cancer) through appropriate history and physical examination.
b) Make a positive diagnosis of musculoskeletal pain (not a diagnosis of exclusion) through an appropriate history and physical examination.

1) Sx emergency
  1. cauda equina syndrome: areflexia, lower extremity weakness, decreased anal tone, saddle anesthesia, fecal incontinence, urinary retention
  2. Ruptured AAA (pulsatile abd mass)
2) Medical conditions:
  • Neoplastic, infectious (osteomyelitis), metabolic, rheumatologic,
  • referred pain – herpes
  • UTI – pyelonephritis
  • Compression fracture
  • spondylosis / spondylolisthesis / disc herniation / spinal stenosis
  • Mechanical / MSK back pain
Red flags: T-BACKPAINS (ref for Tx within 1-2d)
  • Trauma: mild trauma – Compression fracture: acute bony tenderness, osteoporosis – check for stability
  • Bowel (fecal incontinence) or bladder dysfunction (acute urinary retention / overflow incontinence)
    • Cauda Equina (emergency – ref within hrs)
  • Anesthesia: saddle / perineal numbness, loss of sphincter tone, leg weakness, change in sexual function
    • Cauda Equina (emergency)
  • Cancer / Constitutional Symptoms: night pain, wt loss, hx of cancer
  • K-Chronic Dz: worsening symptoms
  • Paresthesia:
  • Age>50 (if first ever episode of serious back pain) – Ref within weeks
  • Infection / IVDU hx / osteomyelitis: fever, chills, sweats
  • Neurologic deficit
  • Spinal cord: Neuromotor deficits (motor/sensory)

Patients with red flags indicating a high likelihood of serious underlying pathology should be referred for immediate evaluation and treatment to an appropriate resource depending on what is available in your region (e.g., emergency room, relevant specialist.)

Yellow flags (psychosocial barriers to recovery) – indicates long-term disability & work loss risk
  • Attitude + belief that pain and activity are harmful
    • Educate & consider referral to active rehab
  • Behaviour: sickness behaviours
    • Educate & consider pain clinic ref
  • Compensation issues: problems with claims
    • Connect with stakeholders and case manager
  • Dx + Tx issues: Hx of back pain, time-off, other claims, persistent pain for 4-6 weeks with little to no improvement in symptoms
    • f/u regularly, ref if recovering slowly
  • Emotions: low / negative mood, social withdrawal
    • Assess for psychopathology & Tx
  • Family: overprotective family or lack of support
    • Educate family & pt
  • Work: poor job satisfaction, problems at work, heavy work, unsociable hours (shift work)
    • Engage case management through disability carrier
    • f/u regularly ref if recovering slowly

Primary care evaluation should include assessment for psychosocial risk factors (‘yellow flags’) and a detailed review if there is no improvement.

Dx: 98% mechanical cause
  • pain worse w/ movement, better with rest
  • sprain (ligament), strain (mm),
  • facet jt degeneration, disc degeneration/herniation, spinal stenosis
  • spondylosis, spondylolisthesis, compression #, pregnancy
2% non-mechanical
  • pain is worse at rest, does not change with position
  • Neurological exam:
    • L2 – hip flexion, L3 – knee extension, L4 – ankle dorsiflexion, L5 – great toe extension, S1 – ankle plantar flexion, S2 – knee flexion
    • Power, reflexes, sensation – to determine level of spinal involvement
  • peripheral pulses, posture, ROM
  • Percussion of spine – illicit # / infection
  • special tests:
    • straight leg raise – pain at <70 & aggravated by ankle dorsiflexion → sciatica
      • crossed straight leg raise – more specific
    • femoral stretch test – prone, flexed knee, examiner extends hip → L4 radiculopathy

Herniated disc:
  • Protrusion of nucleus pulposus, most common secondary to flexion / lifting injury
  • Pain either back (central herniation) or leg (lateral herniation) dominant
  • Abrupt onset of pain, worse with sitting, walking, standing, coughing, flexion
  • Numbness / weakness may be present in nerve root distribution
Lumbar Spinal Stenosis / neurogenic claudication:
  • Narrowing of spinal canal causing nerve compression
  • Risk factor: >60yo
  • Pain is radicular ± back pain, progresses proximal to distal & gradual onset
Sciatica –
pain, numbness, leg weakness caused by pressure on the sciatic nerve (L4-S3)
  • multiple dx shoulder be considered
  • Aggravated by extension, leg pain often subsides with lying / sitting
  • poor walking / standing tolerance
Mechanical back pain
  • Most common cause are degenerative disc or facet processes & muscle / ligament related injuries
  • NO red flags on Hx + PEx & Ix generally not needed
  • Most improve in 1 mo with conservative Tx

Compression #:
local pain (spinal) & no pain radiation
Herniated disc:
Positive SLR & worse with flexion
Spinal stenosis:
worse with extension
Vascular claudication:
worse with walking set distance, better when stop walking <2min, muscular cramping pain
Neurogenic claudication:
worse with walking or standing (distance variable) & better when change position >10min
Mechanical Back pain:
resolved in 2-3 wk, no red flags, often paraspinal pain

2 In a patient with confirmed mechanical low back pain:
a) Do not over-investigate in the acute phase.
b) Advise the patient:
– that symptoms can evolve, and ensure adequate follow-up care.
– that the prognosis is positive (i.e., the overwhelming majority of cases will get better).

Ix: no b/w or imaging unless + red flags
  • If cancer/infection suspected: CBC, ESR
  • X-ray not recommended in initial evaluation
  • If neurologic deficits worsening / infection/ca suspected: CT / MRI
Indications for L-spine X-ray
  • No improvement after 1 month
  • >38oC
  • unexplained w loss
  • prolonged corticosteroid use
  • sig trauma
  • progressive neurological deficit
  • suspicion of ankylosing spondylitis
  • Hx of Ca – r/o mets
  • EtOH / drug abuse – risk of OM, trauma, #

Further Ix if no improvement after 1month

3 In a patient with mechanical low back pain, whether it is acute or chronic, give appropriate analgesia and titrate it to the patient’s pain.


  • Reassurance / educate – nearly always benign & 70% improve in 2 weeks and 90% in 6 weeks
  • Conservative / self care strategies
    • limited bed rest (no evident)
    • stay active and continue usually activities within limits of pain
      • Patients should be advised to stay active and continue their usual activity, including work, within the limits permitted by the pain.
      • Physical exercise is recommended. Patients should limit/pace any activity or exercise that causes spread of symptoms (peripheralization).
    • notes for work & early return to work / activity
      • Refer workers with low back pain beyond 6 weeks to a comprehensive return to-work rehabilitation program.
      • Effective programs involve case management, education about keeping active, psychological or behavioral treatment and participation in an exercise program.
      • Working despite some residual discomfort poses no threat and will not harm patients.
    • Heat or cold packs:
      • In the first 72 hours recommend cold packs (ice), after that, alternate cold and heat as per patient’s preference.
      • Heat or cold should not be applied directly to the skin, and not for longer than 15 to 20 minutes.
    • massage, acupuncture:
      • For some patients with subacute or chronic non-specific low back pain, massage may be beneficial, especially with education and exercises.
      • Some evidence suggests that acupuncture massage may be more effective than classic massage but more studies are required to confirm these results.
    • spinal traction, spinal manipulation, TENS  (no evident)
      • Patients who are not improving may benefit from referral for spinal manipulation provided by a trained spinal care specialist such as a physical therapist, chiropractor, osteopathic physician or physician who specializes in Musculoskeletal (MSK) medicine.
    • The use of shoe insoles or orthoses is not recommended for prevention of back problems.
  • Meds:
    • Prescribe medication, if necessary, for pain relief preferably to be taken at regular intervals.
    • Analgesia: 1st line: tylenol, 2nd line: NSAIDS
    • 3rd line: muscle relaxant (<7d) may be useful )s/e: drowsiness, dizziness, dependency)
    • don’t Rx opioids (last resort)
    • Neuropathic pain – Amitriptyline 10-100mg qhs (start low & go slow) > gabapentin 100mg hs to max of 1200mg tid
  •  Sx:
    • Emergency: cauda equina / AAA
    • worsening neuro deficit
    • intractable pain not responding to conservative Tx
  • Team approach: physio etc ± physiatrist referral & Neuro Sx if appropriate
  • Analgesia: Acetaminophen > NSAIDs > Low-dose TCA > cyclobenzaprine > T#3 > opioids (find the lowest dose, switch to sustained release & short-acting prn for breakthrough pain)

4 Advise the patient with mechanical low back pain to return if new or progressive neurologic symptoms develop.
5 In all patients with mechanical low back pain, discuss exercises and posture strategies to prevent recurrences.

Cases Requiring Further Evaluation: Instruct pt to Schedule an urgent appointment with a physician if any of the red flags are present.

Reassess patients whose symptoms are not resolving.

  • Follow-up in one week if pain is severe and has not subsided.
  • Follow-up in three weeks if moderate pain is not improving.
  • Follow-up in 6 weeks if not substantially recovered.

Approach to Non-traumatic Low Back Pain

Back Dominant (pain greatest above gluteal fold)
  • Pattern 1
    • Worse with flexion & constant / intermittent
    • Normal neuro exam
      • Fast Responder: improves with extension
      • Slow responder: no change or worsens with extension
    • Pathology: arising from intervertebral discs or adjacent ligaments
    • Tx: Scheduled extension, lumbar roll, night lumbar roll, med prn
  • Pattern 2
    • Worse with extension & never with with flexion & always intermittent
    • Normal neuro exam ± improves with flexion
    • Pathology: posterior jt complex (associated ligaments and capsular structures)
    • Tx: scheduled flexion & limited extension. Night lumbar roll + med prn
Leg Dominant (pain greatest below gluteal fold)
  • Pattern 3
    • Pain changes with back movement / position; currently/previously constant
    • PEx: leg pain can improve but not disappear
      • + Straight Leg raise ± conduction loss
      • Fast responder: improves with specific back position
      • Slow responder: not better with position changes
    • Pathology: Sciatica
    • Tx: Prone extension, Supine Z lie, lumbar roll, night lumbar roll, med prn
  • Patter 4
    • Worse with activity & improves with rest & postural change. Intermittent/short duration
    • PEx: No irritative findings ± conduction loss
    • Pathology: Neurogenic claudication
    • Tx: Abdominal exercise, night lumbar roll. Sustained flexion & med prn


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Posted in 61 Low-back Pain, 99 Priority Topics, FM 99 priority topics, Rheum

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