Study Of The Application Of Computer-assisted Technology In Pelvic Surgeries

Objective:To investigate the application of computer-assisted technology in pelvic surgeries,including preoperative virtual surgical planning,computer-assisted surgical navigation and medical augmented reality technology,to improve the preoperative planning,accuracy,safety and ultimately the quality of pelvic surgeries.Materials and Methods:Six cases of acetabular fractures underwent pelvic CTA scan.Based on the scanned data the three-dimensional reconstruction of the pelvis,peripheral blood vessels,skin and soft tissue was completed after segmentation.Then virtual planning of fracture reduction,the design of internal fixation and the optimal operative approach was performed,which served as a guide in the operation.After surgery,the consistency between the real surgery and virtual surgical planning was analyzed;5 titanium screw marks were fixed along the iliac wing on the cadaveric pelvic specimen and then CTA scan was performed.The scanned data was then imported into Mimics software to complete three-dimensional reconstruction of the pelvis,surrounding vessels and bladder.And the ideal path for the sacroiliac screw was virtually planed.After registration,the position of the pelvis and the surgical instrument were tracked in real time.Under the 3D real-time guidance demonstrated on the computer screen of the navigation system,the operator inserted the pin and then the screw.Postoperatively,the three-dimensional model of the pelvis was constructed following CT scan,the position of the screw was evaluated,and the position of the actually drilled screw was compared with the planned virtual path;After the virtual planning of the sacroiliac screw path,the preoperative calibration and registration of surgical instrument,and the calibration of augmented reality helmet,the 3D virtual images shown on the helmet display and real pelvis came to real-time fusion.With the real time 3D guidance of the augmented reality helmet,the surgeon inserted the pins and screws following the virtual path.3D reconstruction of the pelvic was done after postoperative CT scan.The positions of drilled screws were evaluated,and the distance between the virtual planned screw path and the actually drilled screw on the S1 sacral nerve root tunnel level,and their distances at bony insertion point and the screw tip together with the angular deviation were measured.Results:Preoperative virtual surgical planning for 6 cases of acetabular fractures was successfully completed.The designed virtual plates matched the pelvic well.The planned surgical approaches in all 6 cases were identical to the real surgery.The virtual planned fracture reduction was consistent with the intraoperative conditions in 5 patients,and partly consistent in 1 patient.All surgeons were highly satisfied with the virtual planning system;In this study,we realized the real-time 3D navigation in the pelvic surgery without intraoperative radiation,and successfully transformed the preoperative virtual planning results into the operation.Under the intraoperative real-time 3D navigation four S1 sacroiliac joint screws were successfully implanted along the path of the virtual planning.And the postoperative CT scan suggested that the screw positions were satisfying,and consistent with the virtual planned path with no penetration of the cortical cortex;Under the augmented reality navigation we successfully inserted twelve percutaneous S1 sacroiliac screws.Postoperative CT image showed excellent screw position with no penetration of the cortical cortex.The distances between the screw path of virtual planning and the actually drilled screw on the S1 sacral nerve root tunnel level,at the screw insertion point and the screw tip were 3.6±1.0mm,2.7±1.2mm and 3.7±1.1mm respectively,and the angular difference was 2.9°±1.1°.Conclusion:Computer-assisted technology is feasible and shows promising prospect in preoperative planning and intraoperative navigation in pelvic surgeries.It helps orthopedic surgeons to make accurate and individualized preoperative plan,to ensure the accuracy and safety in the surgery,to decrease the possibility of intraoperative damage to adjacent blood vessels and organs,and ultimately to improve the quality of the pelvic surgery.