Perioperative sonography.

Experience using intraoperative real-time sonographic examinations for over a thousand patients has delineated the advantages of this surgical adjunct for a number of cranial and spinal pediatric neurosurgical procedures. Unusual and unfamiliar angles of insonation call for careful attention to anatomy. The advantages of intraoperative sonography in localizing intracerebral tumors, brain abscesses, and foreign bodies are demonstrated. In addition, adequacy of tumor removal can be assessed better at the time of operation and the operative area can be inspected for bleeding even after dural closure. In the pediatric age group, intraoperative real-time sonography is used most commonly for placement of shunts, allowing positioning of the ventricular catheter tip away from the choroid plexus. The use of air as a contrast agent in conjunction with intraoperative sonography allows better identification of catheter tips and can demonstrate the intercommunication of potentially isolated cavities within the brain. Intraoperative sonography has been extremely helpful, especially for identifying cysts within and the extent of intramedullary spinal cord tumors. Visualization of a syrinx is exquisite. Some of the cases presented also serve to identify limitations of intraoperative sonography as a surgical adjunct.