The Use of Intraoperative Ultrasound in Endoscopic Endonasal Surgery of the Craniovertebral Junction: A Technical Note

Background: The transoral approach to the craniovertebral junction (CVJ) is considered be the most standard and direct way to access this region of the upper cervical spine when decompression is mandated. However, because of the morbidity related to this surgical option, the endoscopic endonasal approach (EEA) to the cervicomedullary junction has emerged as a well-accepted modality for accessing this challenging area of the caudal skull base. Because visualization of the dura can be limited and the local anatomy can appear indistinct during decompression, the authors aimed to explore the use of intraoperative ultrasound to assist with capturing images of the surgeon's interaction with the surgical target during EEA to the CVJ.

Objective: The aim of this technical note is to describe the novel clinical application of the ultrasound in endoscopic, endonasal approach for the removal of the anterior arch of C1 and the odontoid process.

Materials and Methods: The authors used the Prosound Alpha 7 Premier (Aloka Co., LTD, Tokyo, Japan) ultrasound to assist with capturing real-time images of the craniovertebral junction and with determining the limit of ventral decompression. An illustrative case example describing the application of the device during surgery is discussed.

Conclusion: The initial experience with the ultrasound is promising. This device guided the authors intraoperatively to ultimately help establish when the surgical goal was achieved. In addition, this case suggests that during EEA the ultrasound is a feasible option for offering supplemental information regarding the localization of critical neural structures, such as the brain stem and spinal cord. Further studies are required to confirm its clinical impact in other areas of the skull base.