Clinical Findings

• 
  

  A 37-year-old man presented with pain in the right buttock radiating to the lateral, which worsens during sitting or standing.

  
  
• 
  

  The patient underwent a diskectomy at the left L4-L5 in 2005.

  
  
• 
  

  The physical examination revealed weakness of the right leg and difficulty in walking.

  
  
• 
  

  An MRI showed an upward-migrated extruded herniated fragment at the L4-L5 level ( Fig. 18.60A ). The axial view showed central to right compression of the nerve root, and the CT scan showed a migrated soft fragment ( Fig. 18.60B,C ).

Surgical Procedures

1. 
   

   The tip of the forceps should face upward in the spinal canal during removal of the upward-migrated herniated fragment under continuous fluoroscopy ( Fig. 18.61A ).

• 
  

  The cannula and the drill tip are positioned at the L4-L5 level during foraminotomy, as confirmed with fluoros-copy in the AP view ( Fig. 18.61B ).

  
  
• 
  

  Decompression is completed with the Ellman tip facing upward in the spinal canal ( Fig. 18.61C ).

  
  
• 
  

  The positions of the needle, dilator, and working cannula are identified and diskography is performed at the L4-L5 level ( Fig. 18.62 ).