Acute Back Pain

Gary Allen and Kevin Gilbert

Background 

  • >90% of back pain is nonspecific and musculoskeletal in nature
  • Acute = < 3 months, Chronic = > 3 months
  • Can’t Miss: spinal cord compression, cauda equina, cancer, infection (spinal abscess, discitis, or osteomyelitis), fracture
  • Corresponding “Red Flags”: urinary/bowel incontinence, weight loss, history of cancer/known active cancer, fevers/chills, IVDU, recent major trauma or osteoporosis risk factors.
  • Radicular pain = pain radiating down legs; radiculopathy = nerve deficit (weakness, numbness, etc.)
  • Axial pain = pain localized to back
  • Spondylosis = degeneration of vertebral column
  • Sponydylolysis = pars interarticularis defect
  • Spondylolisthesis = Vertebral malalignment compared to vertebra below
  • Anterolisthesis = forward movement of vertebra relative to one below it
  • Retro = backward movement of vertebra relative to one below it.

Presentation 

  • Lumbar strain: diffuse pain in lumbar muscles, may radiate
  • Degenerative disk or facet process: localized lumbar pain, similar to lumbar strain
  • Inflammatory arthritis: morning stiffness, improves with movement, systemic symptoms
  • Osteoarthritis: pain with activity, improves with rest
  • Herniated disk: radiating pain to legs, often below the knees
  • Compression fracture: older pts or osteoporosis, trauma, spine tenderness on exam
  • Spinal stenosis: pain improves with flexion (shopping cart sign)
  • Spondylolysis: pain with extension
  • Spondylolisthesis: pain with activity, improves with rest, can be seen with imaging (vertebrae out of alignment)
  • Scoliosis: abnormal spine curvature, seen on physical exam inspection

Evaluation 

  • Physical Exam
    • Inspection: posture, Adam’s Forward Bend Test (screens for scoliosis), limb length discrepancy, spine curvature (kyphosis, lordosis, scoliosis); compare to normal anatomy
    • Palpation/Percussion: sensitive for identifying spinal infection, metastases, or compression fractures
      • Spinous processes, lumbar “step-offs,” paravertebral muscles and SI joint
    • Range of motion: pain with flexion = disc / anterior column pathology; pain with extension = facet pathology / spinal stenosis
    • Neurologic examination
      • L2: hip flexion; L3: medial femoral condyle; L4: medial malleolus; L5: first dorsal webspace; S1: lateral malleolus
      • **Radicular pain does NOT have to match dermatome**
    • Waddell’s Signs: raise suspicion of non-organic pain
      • Superficial tenderness, pain that improves with distraction (attention diverted)
      • Pain with sham maneuvers (simulation)
      • Overreaction (disproportionate psychomotor responses)
      • Non-physiologic neurologic deficits
  • ESR/CRP: can be used if concern for infection or malignancy
Provocation Tests of the Lower Back

Test

Isolates

Action

Positive if
Seated Slump Test Lumbosacral nerve roots Pt is sitting, have them slump forward w/chin touching chest. Then passively extend knee and dorsiflex foot Positive if radicular pain is reproduced with knee extension, relieved by lifting chin/flexing knee. Sensitive for neuroforaminal stenosis
Straight Leg Raise Lumbosacral nerve roots Pt is supine, lift one leg (keep straight) while the other leg is resting flat Positive radicular pain is reproduced with leg elevation. Sensitive for neuroforaminal stenosis
Ankle Dorsiflexion Test Lumbosacral nerve roots At the end of SLR test, lower the leg slightly until pain resolves, then passively dorsiflex ankle Positive if radicular pain reproduced with dorsiflexion; Sensitive for neuroforaminal stenosis
Femoral Nerve Stretch Test Lumbosacral nerve roots Pt prone, maximally flex ipsilateral knee; can accentate by lifting knee off table Positive if radicular pain reproduced; Sensitive for neuroforaminal stenosis, particularly of upper nerve roots
Gaenslen’s Test Sacroiliac Joint Pt supine, brings knee of leg of side not being tested to chest and holds it; examiner extends straight leg being tested over edge of bed Reproduction of pain deep in upper buttocks
Patrick’s (Fabers) Test Sacroiliac Joint Pt supine, passively flex hip to 90º, maximally abduct and externally rotate at hip Reproduction of pain deep in upper buttocks
Sacral Thrust Sacroiliac Joint Pt prone, apply anteriorly directed thrust over sacrum Reproduction of pain deep in upper buttocks

Imaging

  • Indications: risk of fracture, red flag symptoms, evaluating for ankylosing spondylitis, no improvement in pain after conservative therapy after 6-12 weeks
  • AP and lateral plain films; bilateral oblique films (evaluate for spondylolysis); flextion/extension imaging (evaluates for instability iso listhesis)
    • Can show fractures, degenerative disc disease, neuroforaminal narrowing
    • Inferior to MRI for all of the above, but often obtained prior to MRI
  • MRI with and without contrast for suspected cancer, infection
  • MRI without contrast for suspected cauda equina (unless cancer or infection are suspected causes), fracture (can differentiate acute from chronic), refractory to conservative management (in combination with referral to spine specialist
  • T1 images = shows anatomy, fluids are dark, fat is bright
  • T2 images = focuses on pathology ideal for visualizing inflammation or edema. Water- based tissues are bright

Management 

  • First line: conservative therapy for 4 to 6 weeks, avoid bedrest
    • Refer to Spine PT program at VUMC
    • Medications: Tylenol +/- muscle relaxer (Robaxin / Flexiril)
    • Steroids (Medrol Dosepak) often prescribed, not demonstrated to improve outcomes
  • Indications to refer to Orthopedics or PM&R spine specialist
    • Refractory to conservative treatment
    • Severe, debilitating pain at the outset / unable to tolerate PT
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