Online Module: Spine

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Online Module Spine

• Degenerative Disc Disease and Low Back Pain
• Herniated Nucleus Pulposus
• Cervical Spinal Stenosis
• Lumbar Spinal Stenosis

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Degenerative Disc Disease and Low Back Pain
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Degenerative Disc Disease (DJD)

• Unfortunately, DJD seems to be sort of a
  wastebasket term that is often used to describe
  age-related changes on MRI, etc.
• While these changes are indeed degenerative,
  this happens as we age and is not necessarily
  indicative of any significant underlying
  pathology or condition.
• The majority of individuals gt 60 will show some
  type of degenerative change(s) on lumbar imaging.

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DJD

• Degeneration of an individual disc space
  typically refers to loss of disc height, loss of
  water content, fibrosis, end plate
  sclerosis/defects, osteophyte complexes, etc.

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Low Back Pain (LBP)

• LBP is extremely common a majority of
  individuals will experience at least one episode
  of it in their life.
• 85 of LBP is idiopathic, even with workup.
• Most patients with LBP improve on their own in
  time (even without treatment).
• Physical therapy and pain meds (even
  nonprescription such as NSAIDs) are appropriate
  mainstays of initial treatment.

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Taking a history in a pt. with LBP

• Evaluation of patients with LBP should be geared
  towards identification of those patients with a
  potentially serious underlying etiology.
• Cancer
• Infection osteomyelitis, abscess, etc.
• Fracture
• Cauda Equina Syndrome

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Things that should raise a red flag

• Previous hx of cancer, unexplained weight loss
• Immunosuppression, hx of steroid use, hx of IV
  drug abuse, hx of skin/other infection(s)
• Hx of recent falls or trauma (including surgery)
• Bladder dysfunction (usually urinary retention or
  overflow incontinence) or fecal incontinence,
  saddle anesthesia, leg weakness
• Pain that doesnt improve with rest failure to
  improve after 4 weeks conservative management

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Other things to check with LBP

• Social factors are important to ask about.
• Employment status
• Any pending litigation?
• Vitals can give clues (fever with infection,
  etc).
• Routine labs are usually sufficient.
• Good physical exam should pick up neurological
  compromise, if present.
• Palpation of the spine looking for tenderness,
  etc., also important (trauma, infection).

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Radiography

• Currently, radiographic imaging is not
  recommended for patients with no red flags on
  history and physical if they have had symptoms
  less than 4 weeks duration.
• If red flags present, or persistent symptoms
  beyond 4 weeks, radiographic evaluation is
  recommended.
• Then referral as/if appropriate.

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Herniated Nucleus Pulposus
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Concept

• Intervertebral discs can be thought of,
  conceptually, kind of like a jelly donut. The
  outside is the annulus fibrosus, and the inside
  jelly is the more watery nucleus pulposus.
• Intervertebral discs act as shock absorbers
  between the vertebral bodies.
• Just like jelly donuts have a weak spot where
  the jelly squirts out if you squeeze them, the
  annulus of discs is weak posteriorly where the
  nucleus pulposus can herniate through, causing
  symptoms.

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Presentation

• The classic presentation of Herniated Nucleus
  Pulposus (HNP), both for cervical and lumbar
  spine, is radiculopathy.
• The disc herniation impinges upon a nerve root,
  causing characteristic pain.
• Thoracic disc hernations are much, much rarer.
• Though it can cause myelopathy in the cervical
  spine (see Cervical Spinal Stenosis, later),
  Cauda Equina Syndrome in lumbar spine (see
  module), etc., other presentations wont be
  discussed here.

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Lumbar HNP

• Sciatica is the classic radiculopathy of lumbar
  HNP, though the exact presentation depends upon
  the nerve root(s) involved.
• Motor weakness can occur, which again is
  representative of the nerve root(s) involved.
• L4 quadriceps (knee extension)
• L5 tibialis anterior (foot dorsiflexion)
• S1 gastrocnemius (foot plantar flexion)
• Lower Motor Neuron signs

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Lumbar HNP

• 90 of herniated discs are paracentral (slightly
  off to one side) and affect the nerve root that
  corresponds to the lower vertebral level.
• Example a typical L4/5 disc herniation would
  cause symptoms referrable to the L5 nerve root.
• As many as 10 of herniated discs, however, are
  far lateral and impinge upon the nerve root
  that corresponds to the upper vertebral level.
• A far lateral disc hernation at L4/5, then, would
  be expected to cause symptoms relative to the L4
  root.

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Lumbar HNP when to operate

• The natural history of herniated discs is to
  resolve over time. If conservative management
  can adequately treat a patients pain, this is
  the preferred course of action.
• If conservative management fails to adequately
  control pain, surgery can be performed (often
  times on an outpatient basis).

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Lumbar HNP

• Emergent surgery only for new or progressive
  motor deficit, or Cauda Equina Syndrome.
• Urgent surgery sometimes for severe,
  incapacitating pain clearly referrable to a disc
  herniation that is not being adequately treated
  with pain meds/conservative management.
• Diagnostic modality of choice is non-contrast
  MRI.
• Can do myelogram in patients who cant get MRI.

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Cervical HNP

• Classic presentation is to wake up with it.
  Usually no identifiable factor.
• Causes painful limitation of neck motion and
  symptoms corresponding to the affected nerve
  root(s)
• The majority of cervical herniated discs will
  catch the nerve root corresponding to the lower
  vertebral level.
• Ex A C6/7 disc herniation will impinge upon the
  C7 root.

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Cervical HNP

• Just as is the case with Lumbar HNP, conservative
  therapy is the mainstay of treatment.
• Surgery indicated for those that dont improve
  with conservative management, or with
  new/progressive neurologic deficit.

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Cervical Spinal Stenosis
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Cervical Spinal Stenosis (CSS)

• Stenosis a constriction or narrowing of a duct
  or passage.
• Cervical spinal stenosis, thus, is narrowing of
  the spinal canal (within which lies the cervical
  spinal cord).
• This narrowing can be from any of a multitude of
  causes. Usually, though, this is referring to
  more chronic types of processes, rather than
  acute or sudden ones.

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CSS

• More than half of adults older than 50 yrs. Will
  show significant degenerative cervical spine
  disease on radiography (CT/MRI)
• (i.e., Everybody has degenerative disc disease.
  And probably their dogs and cats too.
• however, only a fraction of these patients will
  actually experience any type of significant
  neurological symptoms.

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CSS when it causes problems

• Radiculopathy from nerve root compression.
• The term radiculopathy refers to disease of the
  nerve roots LMN signs, pain/parasethesias.
• Myelopathy from spinal cord compression.
• The term myelopathy refers to pathological
  changes of the spinal cord itself.
• Pain and sensory changes in the back of the head,
  neck, and shoulders.

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CSS - Myelopathy

• The goal here is to avoid missing patients who
  are myelopathic, because once stenosis has
  evolved to the point that it is compressing (and
  causing damage to) the spinal cord, the
  progression of symptoms may be variablebut it is
  going to progress.

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CSS myelopathy - History

• Some patients attribute weakness to getting
  old, and because they arent having neck pain
  (many myelopathic patients dont), they dont
  realize theres a problem that needs addressing.
• Ask about fine motor movements, like buttoning
  buttons, tying shoes, signing checks, handwriting
  changes, using utensils, etc. Clumsiness with
  fine motor skills is common.

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CSS myelopathy - Physical Exam

• Hyperactive reflexes are the most common physical
  exam finding in myelopathy.
• Remember the difference between Upper Motor
  Neuron and Lower Motor Neuron signs.
• Remember symmetry a Hoffmans on one side, if
  not on the other, should raise a red flag.
• Remember that a Babinski reflex, if present, is
  ALWAYS abnormal.

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• T2 weighted MRI, sagittal view This patient has
  multilevel degenerative changes of the cervical
  spine. The bottom two arrows show mild stenosis
  with CSF (white, fluid signal) still flowing
  around the cord. However, the top arrow is
  pointing to the C3/4 level where there is severe
  cervical spinal stenosis, no CSF around the cord
  (compression), and signal change within the
  spinal cord itself (indicating damage).

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Surgery

• The goal of surgery is to halt the progression of
  myelopathy through adequate decompression of the
  area(s) of stenosis.
• Once patients are clinically myelopathic,
  complete return of function and/or remission of
  symptoms almost never occurs.
• This is why they need to be identified early!

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Clinical Pearl

• Future anesthesiologists take note Blood
  Pressure is the spinal cords friend! If you run
  these patients hypotensive under anesthesia, they
  can wake up paralyzed!
• Hypotension can induce an ischemic event within
  the cord at the area of compression/stenosis.
  DONT DO IT!

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Lumbar Spinal Stenosis
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Lumbar Spinal Stenosis (LSS)

• Just as we discussed with Cervical Spinal
  Stenosis, Lumbar Spinal Stenosis can occur
  secondary to anything which narrows the lumbar
  spinal canal, and it can occur in conjunction
  with other conditions/diseases. But when we
  mention it, we are usually referring to a
  chronic, degenerative process that causes spinal
  canal narrowing over time (i.e. spine aging).

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Lumbar Spinal Stenosis

• Remember that the Spinal Cord ends at the Conus
  Medullaris, which is typically located at the
  L1/2 interspace in adults.
• L1/2 is the lumbar level least likely to be
  affected by Lumbar Spinal Stenosis.
• Thus, Lumbar Spinal Stenosis doesnt cause
  myelopathy when it affects the motor system,
  lower motor neuron signs are what youll find.

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LSS - presentation

• The classic presentation of Lumbar Spinal
  Stenosis is Neurogenic Claudication (NC), or
  pseudoclaudication. (60 sensitivity, but
  gt90 specificity).
• Gradually progressive back, thigh, buttock,
  and/or leg pain that is relieved by rest and/or,
  characteristically, a change in posture usually
  through flexion at the hips (sitting or
  squatting, etc.).

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Neurogenic Claudication

• Neurogenic Claudication is thought to arise from
  compression of, irritation to, or ischemia of the
  lumbosacral nerve roots.
• This is in contrast to Vascular Claudication
  (VC), which is secondary to insufficiency of
  vascular supply to meet demand of muscles (pain
  is ischemic, but from muscles).
• Differentiating between the two isnt always
  easy, but you should understand the difference!

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• Anthropoid posture (walking bent-over as though
  theyre pushing a shopping cart) is common in NC,
  and pain may be reproduced with lumbar extension.
• Vascular Lab Studies may help differentiate
  between NC and VC
• Ankle-Brachial Index (ABI)
• Ultrasound

Table 14-18 adapted from Greenbergs Handbook of
Neurosurgery, 6th ed.
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Management

• Unless there is severe neurological deficit,
  conservative medical management is usually tried
  prior to pursuing surgery.
• Pain meds, epidural steroid injections, etc.
• If medical management is unsuccessful, surgery
  for Lumbar Spinal Stenosis is aimed at removing
  the bony lamina and soft tissue elements that are
  contributing to the canal stenosis.