6 mm Medial Displacement

 

Patient  is a 42 year old female who underwent repair of a two level pseudoarthrosis  from L4-S1.  The L45 and L5S1 levels were instrumented following L45 XLIF and L5S1 PLIF.  Neuromonitoring was employed during the procedure, and all pedicle screws tested greater than 20 milliamps - suggesting screw placement within the walls of the pedicles.

Approximately one month postoperatively, the patient developed intermittent numbness localized to  the L4 dermatome on the left.  The patient did not experinece any pain or motor weakness. The numbness persisted for 6 weeks without change.  Because the patient found the sensory changes annoying,  the left sided instrumentation was removed with immediate  resolution of her symptoms.  After three months, she returned to driving a school bus without further issues.