Intraoperative ultrasound for immediate evaluation of anterior cervical decompression and discectomy.

Abstract

An evaluation of whether the immediate operative results can be improved in anterior cervical surgery in patients in whom disc fragments could remain hidden behind a vertebral body or far laterally in the foramen or in canal stenosis that involved a significant amount of a vertebral body. To determine whether intraoperative ultrasonography can provide immediate evaluation of the decompression. The anterior cervical approach has anatomic limitations that prevent good visualization of deep structures. Sequestered disc fragments can be hidden behind the bone of the vertebral body. Even careful preoperative measurements cannot ensure adequate length and width of decompression for stenotic lesions. Three groups of patients were studied. Group 1 contained seven patients with soft disc herniations that were either behind the vertebral body or extended laterally into the neural foramen. Group 2 consisted of five patients with canal stenosis involving at least one third of the length of a vertebral body and causing myelopathic signs and symptoms. Group 3 consisted of four patients with radicular and cord symptoms. All were studied with either magnetic resonance imaging or computed tomography myelography or both. The size of the desired decompression was measured from these studies. A standard anterior decompression using magnification was performed that satisfied the surgeon's visual and tactile evaluation. The operative site was imaged ultrasonically and the decompression extended until preset imaging criteria were met. These criteria were clear root visualization for radiculopathy and good dural pulsations for stenotic lesions. Twelve of the 16 patients did not meet the set criteria on initial imaging, and 11 had their decompression extended. A hidden lateral disc fragment was found in one. In this selected group of 16 patients with complicated cervical pathology, 14 improved neurologically after the use of ultrasonic guidance intraoperatively. One error of interpretation was made. One patient who did not meet the ultrasonic decompression criteria and did not have the decompression extended did not improve after surgery. In complicated anterior cervical decompressions, intraoperative ultrasonic imaging provides immediate evaluation of the extent of the decompressive procedure and may improve the operative result.