Clinical Findings

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  A 47-year-old female presented with right leg pain having lasted for 6 weeks.

  
  
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  Hypoesthesia in the right S1 dermatome was observed.

  
  
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  A preoperative MRI showed a right-side disk herniation that was high-grade upward migrated at L5-S1. A pre-operative CT scan also showed a soft disk ( Fig. 18.101 ).

Preoperative Plan

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  A three-dimensional CT scan helped to visualize the interlaminar space and intended needle trajectory ( Fig. 18.102 ).

  
  
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  The safe space for needle insertion in this case is at the shoulder region of the S1 nerve root ( Fig. 18.103 ).

  
  
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  In addition, another factor favoring the shoulder approach is the medial displacement of the S1 nerve root by the herniated disk taking into account that the origin site of the S1 nerve root is just beyond the disk space.

Surgical Procedures

1. 
   

   The needle is inserted in the shoulder region ( Fig. 18.104A ).

   
   
2. 
   

   The needle tip is close to the medial aspect of the facet joint as identified in the preoperative CT images. Epidurography and radiculography can be used for confirmation of the correct position of the needle tip on the shoulder of the S1 nerve root ( Fig. 18.104B ).

   
   
3. 
   

   The working cannula is placed at an upward angle over the disk space ( Fig. 18.104C ).

   
   
4. 
   

   The working cannula can be seen in the shoulder position in ( Fig. 18.104D).

   
   
5. 
   

   The endoscopic forceps are then used to grasp the upward-migrated disk fragment ( Fig. 18.104E ).

   
   
6. 
   

   The endoscopic forceps can be seen in the shoulder position in Fig. 18.104F .