Abstract
BackgroundStereotactic navigation could improve the quality of surgery for rectal cancer. Critical challenges related to soft tissue stereotactic pelvic navigation include the potential difference in patient anatomy between intraoperative lithotomy and preoperative supine position for imaging. The objective of this study was to determine the difference in patient anatomy, sacral tilt, and skin fiducial position between these different patient positions and to investigate the feasibility and optimal set-up for stereotactic pelvic navigation.MethodsFour consecutive human anatomical specimens were submitted to repeated CT-scans in a supine and several degrees of lithotomy position. Patient anatomy, sacral tilt, and skin fiducial position were compared by means of an image computing platform. In two specimens, a 10-degree wedge was introduced to reduce the natural tilt of the sacrum during the shift from supine to lithotomy position. A simulation of laparoscopic and transanal surgical procedures was performed to assess the accuracy of the stereotactic navigation.ResultsAn up-to-supracentimetric change in patient anatomy was noted between different patient positions. This observation was minimized through the application of a wedge. When switching from supine to another position, sacral retroversion occurred independent of the use of a wedge. There was considerable skin fiducial motion between different positions. Accurate stereotactic navigation was obtained with the least registration error (1.9 mm) when the position of the anatomical specimen was registered in a supine position with straight legs, without pneumoperitoneum, using a conventional CT-scan with an identical specimen positioning.ConclusionThe change in patient anatomy is small during the sacral tilt induced by positional changes when using a 10-degree wedge, allowing for an accurate stereotactic surgical navigation. This opens up new promising opportunities to increase the quality of surgery for rectal cancer cases where it is difficult or impossible to identify and dissect along the anatomical planes.
Highlights
Surgical navigation was developed by neurosurgeons who integrated medical imaging and stereotaxy [1]
Rectal surgery is performed in patients with variable degrees of lithotomy, a position that is different from the supine position used for acquisition of preoperative imaging
An up-to-supracentimetric change in patient anatomy was noted between different positions for all human anatomical specimens
Summary
Surgical navigation was developed by neurosurgeons who integrated medical imaging and stereotaxy [1]. It helps the surgeon to identify anatomical structures, which should be targeted or avoided These systems are currently mainly used in brain, skull base, and vertebral surgery, and they have proven to be an essential adjunct to surgical procedures where anatomical landmarks are obscured and cannot be used for topographic orientation [2]. Rectal surgery is performed in patients with variable degrees of lithotomy, a position that is different from the supine position used for acquisition of preoperative imaging. This positional change could alter the patient anatomy and subsequently render stereotactic pelvic navigation using preoperative imaging inaccurate. Sacral tilt, Presented at the SAGES 2017 Annual Meeting, March 22-25, 2017, Houston, Texas.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
