Water-soluble intrathecal contrast material was used for radiographic identification of the cord target in 13 patients undergoing percutaneous lateral cervical cordotomy. Adequate visualization of the dentate ligament, considered essential for successful placement of the electrode, was achieved in seven cases. In the remaining six patients, four with suboptimal definition and two with nonvisualization of the ligament, an additional injection of contrast medium using a modified coaxial needle system outlined the entire thickness of the cervical cord. This technique improved needle-tip positioning in relation to the cord and resulted in successful surgery in all six patients.
