Femoral nerve palsy. An unusual complication of anterior lumbar interbody fusion.

SUMMARY OF BACKGROUND DATA: Compression neuropathy of the femoral nerve has been reported as an uncommon complication of bleeding into the iliopsoas muscle.

OBJECTIVE

The authors detected anatomic reasons of direct injury to the femoral nerve at the lower lumbar level.

METHODS

Keeping the hip in extension during the course of carrying out anterior fusion on a previously failed posterior fusion was considered another causative factor of femoral nerve injury. Anatomical dissection confirmed the likelihood of this injury being produced in this situation.

RESULTS

Femoral nerve traction and compression can occur after prolonged compression of the nerve within the psoas muscle stretched between an immobile lower lumbar spine and the lesser trochanter when the hip is kept in extension. In the patients described no other reasons for direct or indirect injury were identified.

CONCLUSION

Although uncommon, the complication should be kept in mind. It can be avoided by intraoperative hip flexion.