22.1 Case Presentation

A 52-year-old woman presents to the clinic with right leg pain of 6-month duration. The patient denies any benefit from nonoperative management prescribed by her primary care physician, which included nonsteroidal anti-inflammatory drugs (NSAIDs), epidural steroid injections, and physical therapy. On physical examination, the patient exhibits a positive straight leg test and sensory deficits along the lateral leg. The patient also demonstrates mild weakness on great toe dorsiflexion. There is no noted hypo- or hyperreflexia or Babinski’s sign present. Lumbar radiographs are shown in Figs. 22.1 and 22.2 . The patient’s radiographs and magnetic resonance imaging (MRI) are presented. The patient is subsequently scheduled to receive a minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) of the L5S1 disk space.

22.2 Indications

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  Lumbar disk herniations.

  
  
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  Compression of lumbar nerve roots.

  
  
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  Lumbar instability.

  
  
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  Access to the posterior lumbar spine with minimal blood loss and shortened patient recovery time.

22.3 Positioning

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  Prone.

  
  
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  Landmarks identified through fluoroscopic imaging:

  
  
  
  
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    Spinous processes.

    
    
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    Pedicular line (lateral edge of the pedicle).

22.4 Approach

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  Superficial dissection:

  
  
  
  
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    The skin incision is made lateral to the midpedicular line (1.0 cm; Fig. 22.3a ):

    
    
    
    
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      Lateral fluoroscopy is utilized to confirm the location of the placed dilators at the correct level ( Fig. 22.3b ).

      
      
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      There is no true internervous plane here, as the incision and entry point is made in between the paraspinal muscles, which are segmentally innervated.

    
    
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    Dilators are docked over the lamina at the level of pathology with removal of residual paraspinal musculature.

  
  
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  Deep dissection:

  
  
  
  
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    The lamina and facet joint are resected:

    
    
    
    
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      The superior articular process of the caudal vertebrae is removed first during the facetectomy:

      
      
      
      
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        Inadequate facet removal can result in a narrowed working space, increasing the risk for excessive nerve root retraction and interbody cage misplacement/migration.

    
    
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    Once laminectomy and facetectomy are completed, the ligamentum flavum is removed:

    
    
    
    
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      The disk space, dura, and nerve root are exposed ( Fig. 22.4 ).

      
      
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      Veins overlying the disk space and dura can cause profuse bleeding.