Low Back Pain

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Low Back Pain

• Anca Popescu, MD

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Trivia

• Low Back Pain affects at least 80 of the general
  population at some point in time
• 90 of back pain sufferers recover completely
  within 6 weeks
• For the 10 of patients who do not recover within
  a few weeks, back pain can be a painful,
  prolonged, costly and frustrating experience
• Most abnormalities seen on MRI scans are painless
• Physical and psychological factors contribute to
  a persons experience of back pain

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Sources of Back Pain

• Muscles
• Ligaments
• Tendons
• Bones
• Facet joints
• Discs (the outer rim of the disc, the annulus,
  can be a source of significant back pain due to
  its rich nerve supply and tendency towards
  injury)

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The Intervertebral Disc

• Jelly doughnut acting as shock absorber
• Two parts tough outer core (annulus fibrosus)
  and soft inner core (nucleus pulposus)
• At birth, 80 of the disc is water
• Aging ? disc dehydration ? micromotion
  instability ? inflammatory proteins of nucleus
  pulposus leak out of the disc space ?
  inflammation of structures next to the disc (e.g.
  nerve roots) ? pain

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The Facet Joints

• Paired joints
• Have cartilage on each surface and a capsule
  around them. Cartilage can degenerate as one ages
  ? degenerative arthritis
• The three-joint complex (2 facets and the disc)
  at each vertebral segment allows for motion in
  flexion, extension, rotation, and lateral bending
  (motion segment)

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The Nerve Roots

• In the cervical spine, the nerve root is named
  for the lower segment that it runs between (e.g.
  C6 at C5-C6 segment)
• In the lumbar spine, the nerve is named for the
  upper segment that it runs between (e.g. L4 at
  L4-L5 segment)
• The nerve passing to the next level runs over a
  weak spot in the disc space ? discs tend to
  herniate (extrude) right under the nerve root ?
  leg pain or arm pain (radiculopathy)

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The Nerve Roots (contd)

• A herniated disc may cause only leg pain and not
  low back pain ? may initially be thought to be a
  problem with the leg/arm.
• Leg pain from a lumbar disc herniation will
  usually run below the knee to the foot, and may
  be accompanied by numbness

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Anterior Longitudinal Ligament

• Anterior to the vertebral bodies and discs,
  resists extension
• Rupture by hyerextension injuries (esp cervical)

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Posterior Longitudinal Ligament

• Post aspect of vertebral bodies/ discs
• Forms anteromedial wall of spinal canal
• Hourglass shape in thoracolumbar, narrow over
  bodies flaring at disks
• Disrupted in hyperflexion injuries

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Ligamentum Flavum

• Bridges intervals between laminae
• Laterally-blends with ant capsule of facet joints
• Resists spinal flexion
• Buckles with disk dessication ? could lead to
  central cord contusion/syndrome

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The Vertebrae
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• 50 of flexion occurs at the hips, and 50
  occurs at the lumbar spine
• Motion is divided between the 5 lumbar motion
  segments, although a disproportionate amount of
  the motion is at L4-L5 and L3-L4
• Consequently, these two segments are the most
  likely to break down with degeneration ? may
  become unstable ? excess of motion ? pain

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• During embryological development there is a great
  deal of overlap of nerve supply to all of these
  structures
• Therefore, it impossible for the brain to
  distinguish between injury to one structure
  versus another ? a torn or herniated disc can
  feel identical to a bruised muscle or ligament
  injury

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Muscles that Support the Spine

• Extensors (back muscles erector spinae,
  cervical, thoracic and lumbar paravertebrals and
  gluteals)
• Flexors (abdominal muscles and iliopsoas)
• Obliques / rotators (side muscles)

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Role of Exercise

• Regular exercise stretches back muscles ?
  increase resistance to strain, tear or spasm ?
  less likely to develop back pain from muscle
  strain
• A complete exercise program consists of a
  combination of stretching, strengthening, and
  aerobic conditioning
• Most muscles do not get adequate exercise from
  daily activities and tend to weaken with age

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Muscle Strain

• Most common cause of acute low back pain
• Causes lifting heavy objects, sudden movements
  or falls
• Pathogenesis muscle strain ? inflammation ?
  spasm ? severe pain ? difficulty moving ?
  deconditioning
• Prognosis good (spontaneous healing due good
  muscle blood supply)
• Time course several hours ? few weeks
• Pain gt 2 weeks ? muscle weakness and wasting
  (disuse atrophy) ? muscles are less able to help
  hold up the spine ? more pain

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Axial Low Back Pain

• Description sharp or dull, constant or
  intermittent, mild or severe, worse with certain
  activities and position changes and relieved by
  rest
• Exact diagnosis as to which structure is causing
  the pain is rarely possible and has little
  significance to treatment
• The presence of a herniated, degenerative disc or
  bulging disc on MRI may have nothing to do with
  the pain episode

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Treatment of Axial Back Pain

• Rest
• Physical therapy
• Medications
• Recovery within 6 weeks (in 90 of cases)
• If pain persists gt 6 -8 weeks, additional testing
  and/or injections may be useful in diagnosing and
  treating the source of pain.
• Surgery is rarely recommended (unpredictable
  effect)

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Radicular Pain

• Description deep, steady, reproducible with
  certain activities (eg, sitting or walking)
  numbness and tingling, muscle weakness and loss
  of specific reflexes
• Distribution the affected extremity along the
  course of a spinal nerve root
• Etiology
• - Herniated disc with nerve compression
• - Foraminal stenosis from osteoarthritis
  / osteophytes
• - Diabetes
• - Nerve root injuries
• - Scarring from previous spinal surgery
• Pathogenesis compression, inflammation and/or
  injury to a spinal nerve root

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Lumbar Radiculopathy

• L5 runs over the top of the foot and for S1 it
  runs on the outside of the foot
• L5 radiculopathy weakness of foot dorsiflexion
  and big toe extension ? inability to heel walk
• S1 radiculopathy gastrocnemius weakness ?
  inability to toe walk and loss of ankle jerk

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Sciatica

• Distribution low back ? buttock ? back of the
  leg ? foot / toes
• Description burning/ tingling/ shooting pain
  down the leg, worse with sitting and standing up
• Associated symptoms weakness, numbness or
  difficulty moving the leg or foot
• Pathogenesis
• - herniated disc
• - lumbar spinal stenosis
• - degenerative disc disease
• - spondylolisthesis
• Prognosis good (improvement in two weeks to a
  few months)

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Treatment of Sciatica

• Physical therapy, osteopathic/ chiropractic
  procedures
• (relieve the pressure)
• Medical (NSAIDs, oral steroids, epidural steroid
  injections)
• for inflammation.
• Surgery (microdiscectomy/ laminectomy)
  
• relieves both pressure and inflammation

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Physical Therapy

• Strengthening
• General stretching
• McKenzie method of passive end-range stretching
• Conventional physical therapy
• hot packs
• massage and stretching
• flexibility
• coordination exercises

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• An Australian study indicated that a television
  campaign advising people with back pain to stay
  active and keep working reduced work-injury
  claims and medical expenses
• Buchbinder R, Jolley D. Population based
  intervention to change back pain beliefs three
  year follow up population survey
• BMJ 2004328321

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Muscle Relaxants

• Tizanidine (centrally acting alpha2 agonist)
  analgesia, sedation, myorelaxant
• Cyclobenzaprine ? Central effects (brainstem)
  used for short term only. Side effects
  dizziness, drowsiness, dry mouth. Likelihood of
  pain relief at 14 days is 5 times higher than
  with placebo highest efficacy early (first week)
  
• Browning R, Jackson JL, OMalley PG.
  Cyclobenzaprine and back pain a metaanalysis.
  JAMA 2001 1611613-20
• Carisoprodol and methocarbamol (central action).
  Side effects drowsiness, tremor, tachycardia,
  orthostasis
• Benzodiazepines (diazepam) increase GABA release
  (inhibitory)

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Analgesics

• Tramadol
• central effects mediated via mu receptors
• (affinity 6000 times less than the opioids)
• Opioids
• analgesia at different levels of CNS
• (spinal cord, basal ganglia, limbic system)
  morphine, codeine, hydrocodone, oxycodone,
  fentanyl, hydromorphone, methadone

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NSAIDs

• Central and peripheral mechanisms (reduction of
  cyclooxygenase and leukotrienes which sensitize
  nerve fiber endings to bradykinins and
  leukotrienes)
• Efficacy of analgesia is not proportional to a
  given NSAID antiinflammatory potency.
• McCormack K, Brune K. Dissociation between
  the antinociceptive and antiinflammatory effects
  of the nin-steroidal antiiflammatory drugs a
  survey of their analgesic effects. Drugs 1991
  41 533-47
• NSAIDs have roughly equivalent analgesic efficacy
• Gotzsche PC. Non-steroidal antiinflammatory
  drugs. Br Med J 2000 3201058-61

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Anticonvulsants

• Decrease pain by decreasing membrane excitability
  of neurons
• (raise depolarization potential threshold)
• No well designed, prospective, randomized
  controlled studies in radiculopathy
• Gabapentin, pregabalin, lamotrigine, topiramate
  (newer anticonvulsants) better tolerated than the
  old ones. Gabapentin enhances the the acute
  analgesic effect of morphine when administered
  concomitantly
• Eckhardt K, Ammon S, Hoffman U et al.
  Gabapentin enhances the analgesic effect of
  morphine in healthy volunteers. Reg Anesth Pain
  Med 2000 91 185-91

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Antidepressants

• Tricyclic and tetracyclic drugs small but
  consistent benefits in pain reduction in
  randomized trials in patients with chronic low
  back pain, without clinical depression (a 20 -40
  greater reduction in pain than with placebo,
  during 4-8 weeks)
• Staiger TO, Gaster B, Sullivan MD, Deyo RA.
  Systematic review of antidepressants in the
  treatment of chronic low back pain. Spine
  2003282540-5
• nortriptyline (25 to 100 mg)
• amitriptyline (50 to 150 mg)
• maprotiline (50 to 150 mg)

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Trigger Point Injections

• Taut bands of muscle, foci of irritability
• When compressed cause referred pain and
  tenderness (nociceptors?central and peripheral
  sensitization).
• May be active or latent
• Commonly in the multifidus, longissimus,
  iliocostalis, quadratus lumborum
• Injection technique thin gauge needle inserted
  rapidly through the skin ? twitch response
• Injections can be performed with saline,
  ketorolac, steroids, or dry needling technique

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When to Operate?

• Severe pain that is refractory to manual and
  medical treatments
• If there is significant muscle weakness.
• Radicular pain/leg pain gets relieved in 85 to
  90 of patients.
• Relief of low back pain is much less predictable.
  
• If nerve compression cannot be documented on an
  MRI or CT myelogram, surgery is unlikely to be
  successful

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Spinal Fusion Surgery

• Possible efficacy in patients with isolated one-
  or two-level spondylosis and few or no coexisting
  factors for chronic pain (e.g., disputed
  compensation issues, psychological distress, or
  other types of chronic pain)
• No better results in patients with multiple
  coexisting factors than aggressive nonoperative
  management
• Ivar Brox J, Sorensen R, Friis A, et al.
  Randomized clinical trial of lumbar instrumented
  fusion and cognitive intervention and exercises
  in patients with chronic low back pain and disc
  degeneration. Spine 2003281913-21

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Types of Lower Back Pain that Indicate a Surgical
Emergency

• Sudden bowel and/or bladder incontinence (cauda
  equina syndrome)
• Progressive weakness in the legs (cauda equina
  syndrome)
• Severe, continuous abdominal and back pain (e.g.
  abdominal aortic aneurysm)

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Cauda Equina Syndrome
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Patients Requiring an Immediate Evaluation
(Worrisome Symptoms)

• Fever and chills
• History of cancer with recent weight loss
• Severe trauma
• Significant leg weakness
• Pain worse at night (especially if it wakes up
  from deep sleep)

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Causes of Low Back Pain for Young Adults (lt 60)

• Disc herniation ? buttock/ leg pain radiating
  down to the foot, worse after a long period of
  standing or sitting numbness down the leg
• Degenerative disc disease ? mechanical low back
  pain (pain caused by movement bending forward,
  running). May result from a twisting injury that
  weakens the disc
• Stress fracture or spondylolisthesis ? stress on
  the disc ? low back pain leg pain worse when
  standing or walking

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Low Back Pain for Older Adults (gt60)

• Facet joint osteoarthritis (degenerative
  arthritis) ? low back pain that is worse in the
  morning and in the evening stiffness. Caused by
  a loss of the cartilage between the facet joints
  in the back
• Lumbar spinal stenosis or degenerative
  spondylolisthesis ? pain down the legs when
  walking and standing upright. Caused by pressure
  on the nerves at the point where they exit the
  spine

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Terminology used in Back Pain

• Spondylosis arthritis of the spine
• Spondylolisthesis anterior displacement of a
  vertebra on the one beneath it
• Spondylolysis a fracture in the pars
  interarticularis where the vertebral body and the
  posterior elements, protecting the nerves are
  joined
• Spinal stenosis local, segmental, or generalized
  narrowing of the central spinal canal
• Radiculopathy impairment of a nerve root
• Sciatica pain, numbness, tingling in the
  distribution of the sciatic nerve
• Cauda equina syndrome loss of bowel and bladder
  control and numbness in the groin and saddle area
  of the perineum, associated with weakness of the
  lower extremities
• Lordosis, kyphosis, scoliosis
• Piriformis syndrome thought to be a condition in
  which the piriformis muscle compresses or
  irritates the sciatic nerve

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Differential Diagnosis of Low Back Pain

• Mechanical low back or leg pain (97)
• Lumbar strain, sprain (70)
• Degenerative processes of disks and facets,
  usually age-related (10)
• Herniated disk (4)
• Spinal stenosis (3)
• Osteoporotic compression fracture (4)
• Spondylolisthesis (2)
• Traumatic fracture (lt1)
• Congenital disease (lt1)
• Severe kyphosis, Severe scoliosis, Transitional
  vertebrae Spondylolysis, Internal disk disruption
  or diskogenic low back pain

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Differential Diagnosis of Low Back Pain

• Visceral disease (2)
• Disease of pelvic organs
• (Prostatitis, Endometriosis, Chronic pelvic
  inflammatory disease)
• Renal disease (Nephrolithiasis, Pyelonephritis,
  Perinephric abscess)
• Aortic aneurysm
• Gastrointestinal disease (Pancreatitis,
  Cholecystitis, Penetrating ulcer)

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Differential Diagnosis of Low Back Pain

• Non-mechanical spinal conditions (1)
• Neoplasia (Multiple myeloma, Metastatic
  carcinoma, Lymphoma and leukemia, Spinal cord
  tumors, Retroperitoneal tumors, Primary vertebral
  tumors)
• Infection (Osteomyelitis, Septic diskitis,
  Paraspinous abscess, Epidural abscess, Shingles)
• Inflammatory arthritis (Ankylosing spondylitis,
  Psoriatic spondylitis, Reiter's syndrome
  Inflammatory bowel disease)
• Scheuermann's disease (osteochondrosis)
• Paget's disease of bone

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Vascular Claudication vs. Neurogenic
Pseudoclaudication

• Vascular Neurogenic claudication "pseudo
  claudication
• Femoral or aortic bruit 54 9
• Normal femoral, popliteal,
• and dorsalis pedis pulses 0 83
• Same distance to claudication 88 38
• Mean time to relief
• of walking-induced symptoms 5.0 minutes 12.7
  minutes
• Pain on standing alone 27 65
• Pain with coughing or sneezing 0 38
• Paresthesias on walking 12 43
• Sensory deficit 12 55
• Muscle weakness 12 39
• Limited straight leg raising 0 30

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Interventional Therapies for Low Pack Pain

• Sciatica or Prolapsed Lumbar Disc with
  Radiculopathy
• Chemonucleolysis (2B) moderate benefit
• Epidural Steroid Injection (2B) moderate
  benefit short term only
• Local Injections (2C) unable to determine
• Intradiscal Corticosteroid Injection (2C) no
  effect
• Presumed Discogenic Low Back Pain
• Intradiscal Electrothermal Therapy (2B) unable
  to determine
• Percutaneous Intradiscal Radiofrequency
  Thermocoagulation (2B) no effect
• Radiofrequency Denervation (2C) unable to
  determine
• Intradiscal Corticosteroid Injection (2C) no
  effect
• 2B (weak recommendation moderate quality
  evidence)
• 2C (weak recommendation low quality evidence)

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Interventional Therapies for Low Pack Pain

• Spinal Stenosis
• Epidural Steroid Injection (2C) no effect
• Presumed Facet Joint Pain
• Facet joint (intra-articular) injection (2C) no
  effect
• Medial Branch Block (Therapeutic) (2C) unable
  to determine
• Radiofrequency Denervation (2C) unable to
  determine
• Non-specific Low Back Pain
• Botulinum Toxin Injection (2C) moderate
  benefit short term only
• Epidural Steroid Injection (2C) unable to
  determine
• Local Injections (2C) unable to determine
• Prolotherapy (2B) no effect

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Chronic LBP w/o HNP
Facet Block x2
Positive
Negative
Diagnosis Facet Joint Pain
No SI joint features
SI joint features
SI injection
Provocative Discography
Negative
Positive
Provocative Discography
Concordant Pain
Diagnosis SI Joint Pain
Diagnosis Discogenic Pain
Positive
Negative
Diagnosis Discogenic Pain
Epidural injections
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