Intraoperative ultrasound imaging of the spinal cord: syringomyelia, cysts, and tumors--a preliminary report.

Dynamic intraoperative imaging of the spinal cord was done using a real-time ultrasound scanner. Prior to opening the dura mater the neurosurgeon is able to "explore" the intradural space and with a 7.5 MHz transducer visualize the normal spinal cord, including the central canal and the dentate ligaments. Anterior and posterior spinal arteries may be seen in certain patients. In syringomyelia the fluid-filled cavities may be visualized with ultrasound and drained or shunted with intraoperative ultrasound guidance. Spinal cord cysts or cystic components of tumors can be precisely identified and drained using ultrasound. Intramedullary tumors can be demonstrated sonographically, as can the location and extent of intradural extramedullary tumors and tumors that have both extradural and intradural components. Experience to date with intraoperative imaging of the spinal cord and with the real-time ultrasound scanner is very encouraging, and in the future it should allow for a more precise characterization of and operative approach to lesions of the spinal cord.