Clinical Findings

• 
  

  A 43-year-old man presented with left leg pain that was scored at 5/10 and back pain that was scored at 7/10 on the visual analog scale (VAS).

  
  
• 
  

  The patient’s chief complaint is left flank and buttock pain.

  
  
• 
  

  Preoperative imaging shows a left paramedian extrusion of a ruptured disk with upward migration at the L1-L2 level ( Fig. 18.10 ).

Preoperative Plan

• 
  

  The skin entry point is ~11 cm from midline ( Fig. 18.11 ).

  
  
• 
  

  Parallel or mild caudal to cranial angulation of trajectory is needed.

Surgical Procedures

1. 
   

   The angle of needle insertion is parallel to the upper end plate of the lower vertebral body, and the tip of the needle is positioned at the midpedicular line ( Fig. 18.12 ).

   
   
2. 
   

   After sequential dilators, the working channel is inserted ( Fig. 18.13 ).

• 
  

  The upward-migrated disk fragment is removed after making a caudal to cranial angulation of the working channel ( Fig. 18.14 ).