Clinical Findings

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  A patient presented with right leg pain having lasted for 4 months.

  
  
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  Weakness of the right hallux for plantar flexion was observed.

  
  
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  A preoperative MRI showed a right-side herniated disk lying mainly in the axillary portion of the S1 nerve root at the L5-S1 level ( Fig. 18.107 ).

Preoperative Plan

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  The initial needle target point is just below the superior end plate of S1.

  
  
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  It is possible to have a potential working space in the axillary portion ( Fig. 18.108 ).

  
  
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  The working cannula can be shifted slightly upward from this location to remove the herniated fragment.

  
  
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  The intended trajectory and the skin entry point are midway between the S1 pedicle and midline ( Fig. 18.108 ).

Surgical Procedures

1. 
   

   The needle tip is located in the lower half of the inter-laminar window, which is midway between the inter-spinous and medial pedicular line ( Fig. 18.109A ).

   
   
2. 
   

   The working cannula is then shifted toward the disk space for removal of the intracanalicular herniated fragment and then for the removal of the loose intradiskal nuclear fragments. The tip of the forceps is in the posterior confines of the disk space ( Fig. 18.109B ).