Clinical Findings

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  A 36-year-old man presented with left L4 dermatomal pain for 1 month.

  
  
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  The VAS result was left leg pain 9/10 and back pain 3 to 4/10.

  
  
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  The preoperative sagittal MRI showed a herniated disk at the L3-L4 level with downward migration. The axial view showed a left paramedian ruptured disk fragment, and a CT scan revealed a soft disk ( Fig. 18.36A–C ).

Preoperative Plan

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  The skin entry point is selected by drawing various lines as shown in the axial MRI and the distance from midline is ~11.2 cm. The needle trajectory is directed 20 degrees cranial to caudal ( Fig. 18.36D ).

Surgical Procedures

1. 
   

   A slight downward angle of the needle is needed for an easier approach to the downward-migrated disk ( Fig. 18.37A,B ).

   
   
2. 
   

   The ventral surface of the superior facet and the superomedial corner of the pedicle are drilled to prepare a path to the disk ( Fig. 18.37C,D ).