20.1 Case Presentation

A 59-year-old woman presents to the clinic complaining of a 9-month history of bilateral lower extremity pain and dysesthesias radiating into her right lateral thigh and medial calf. She describes her pain as constant and only improved when leaning forward. She states her pain is worsened with activity including standing and walking for extended periods of time. She denies any improvement in her pain after 6 months of physical therapy and epidural injections. On physical examination, the patient demonstrates weakness in great toe extension in the right foot and sensory deficits at the dorsum of the foot. There is no hyper- or hyporeflexia when eliciting the right Achilles’ tendon reflex. The patient’s radiographs and magnetic resonance imaging (MRI) are presented in Figs. 20.1, 20.2 . The patient was scheduled to undergo an open posterolateral lumbar fusion (PLF) of the L4–L5 interspace.

20.2 Indications

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  Lumbar nerve root compression.

  
  
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  Lumbar instability.

  
  
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  Posterior lumbar tumors.

  
  
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  Posterior lumbar infection or abscess.

20.3 Positioning

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  Prone position.

  
  
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  Superficial landmarks include the following:

  
  
  
  
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    Iliac crest:

    
    
    
    
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      Typically lies at the L4–L5 intervertebral disk level.

    
    
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    Spinous processes:

    
    
    
    
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      The ideal method of identifying the level of interest is to insert a needle into the spinous process and obtain a radiograph via fluoroscopy.