It has been widely reported a vascular and neurologic damage of the lumbar muscles produced in the classic posterior approach for lumbar spinal fusions.

No significant differences in radiologic and clinical outcome were found, in either group. Both procedures appear to be safe and effective surgically and radiographically.

In this series, cortical violation is highly unlikely in patients whose stimulation threshold lies between 6 and 20 mA with values 60% to 65% decreased from the mean (98% negative predictive value). Although verification of screw placement should not depend solely on stimulation thresholds, pedicle screw stimulation provides rapid and useful intraoperative information on screw placement during procedures involving the use of thoracic pedicle screws.