[Sonography aided computer assisted surgery (SACAS) in orbital surgery].

Area of Science:

• Neurosurgery
• Medical Imaging
• Computer-Assisted Surgery

Background:

• Intraoperative tissue shift in orbital surgery complicates computer-assisted procedures due to discrepancies between preoperative CT/MR datasets and actual anatomy.
• Accurate intraoperative imaging is crucial for navigating complex orbital structures, especially in cases involving frontobasal tumors.

Observation:

• A novel approach integrated intraoperative sonography with a navigation system in five patients undergoing orbital surgery for frontobasal tumors.
• The ultrasound unit was coupled to the navigation system after preoperative CT/MR data acquisition.

Findings:

• Registration, referencing, and calibration of the navigated ultrasound system were successful without complications.
• Sonography effectively visualized intraoperative tissue shift in the anterior and middle thirds of the orbit.
• Fusion of intraoperative sonography with preoperative CT/MR data allowed for repeated re-evaluation and visualization of anatomical structures.

Implications:

• Navigated sonography enhances surgeon's spatial orientation and identification of anatomical structures during orbital surgery.
• This technique facilitates increased operative radicality and improved tissue protection.
• The parallel application of navigated sonography and CT/MRT-based navigation systems addresses anatomical complexity in orbital tumor surgery.