Transiliac-transsacral screw fixation is challenging in clinical practice as the screws need to break through six layers of cortical bone. Transiliac-transsacral screws provide a longer lever arm to withstand the perpendicular vertical shear forces. However, the screw channel is so long that a minor discrepancy can lead to iatrogenic neurovascular injuries. The development of medical robots has improved the precision of surgery. The present protocol describes how to use a new teleoperated robotic system to execute transiliac-transacral screw fixation. The Robot was operated remotely to position the entry point and adjust the orientation of the sleeve. The screw positions were evaluated using postoperative computed tomography (CT). All the screws were safely implanted, as confirmed using intraoperative fluoroscopy. Postoperative CT confirmed that all the screws were in the cancellous bone. This system combines the doctor's initiative with the Robot's stability. The remote control of this procedure is possible. Robot-assisted surgery has a higher position-retention capacity compared with conventional methods. In contrast to active robotic systems, surgeons have full control over the operation. The robot system is fully compatible with operating room systems and does not require additional equipment.

Abstract Background The use of interlocked intramedullary nail has become the preferred method of treatment for intertrochanteric fracture of the femur. This study explored a new guide awl with a distal positioner assisting the guide wire insertion and opening canal, and verification the accuracy and security of our new guide awl.Methods 42 patients with intertrochanteric fracture treated by locking intramedullary nailing were retrospectively analyzed. Three patients with insufficient follow-up were excluded from analysis. 19 patients underwent the operation using the new guide awl, the other 20 patients in the control group were operated with the help of the conventional guide apparatus. Describe the new guide awl with a distal positioner usage in the operations. Operation time, the success rate of one-time insertion, fluoroscopy time, blood loss and bone healing time were recorded.Results 42 patients (25 males and 17 females) were treated with Gamma 3 and PFNA with the help of the new guide awl with a distal positioner or the conventional conventional guide apparatus. The surgical time in new guide awl group was significantly shorter compared to the control group. The success rate of one-time needle insertion in the new guide apparatus group was 89.5%, which was higher than the 65% of the control group. The fluoroscopy time in new guide apparatus group is obviously lower than in the control group. There was no significant difference in intraoperative blood loss and bone healing time.Conclusion The new guide awl with a distal positioner we designed could reduce the difficulty in opening the femur for inserting the interlocked intramedullary nail. It is especially suitable for obese patients.

Objective:To evaluate the significance of S1 posterior edge inlet view for placement of percutaneous sacroiliac screws.Methods:1. CT data of the pelvis were collected from 134 normal adults and introduced into Mimics Medical 21.0 system. Anatomical parameters of sacral vertebrae were measured and analyzed to observe the anatomical disparities between the anterior and posterior edges of S1 vertebral body. A mathematical model was established using the data acquired. 2. Manual placement of sacroiliac screws was performed using a conventional S1 posterior edge inlet view on the pelvic specimens from 5 adult cadavers in simulation of actual surgical situations. After placement, the inlet views from both the S1 anterior and posterior edges were taken to observe the imaging differences and to check if the screws had pierced the sacral canal. 3. A retrospective study was conducted of the 11 patients with posterior pelvic ring fracture who had been treated at Department of Orthopaedics, Tongji Hospital from January 2019 to October 2020. Their fractures were fixated by percutaneous sacroiliac screws under the guidance of a C-arm X-ray machine. The manual placement of the screws was guided intraoperatively by the inlet views from both the S1 anterior and posterior edges to secure a safe placement. Pelvic CT examinations were performed to check any screw dislocation.Results:1. CT measurements in the normal adults showed that the angle of S1 anterior edge inlet view (20.71°±11.89°) was smaller than that of S1 posterior edge inlet view (41.99°±11.67°) and the width of S1 upper end plate [(32.22±3.41) mm] greater than that of S1 lower end plate [(20.10±3.28) mm], showing significant disparities in anatomy between the anterior and posterior edges of S1 vertebral body ( P<0.05). 2. In 2 of the 5 cadaveric specimens, imaging differences were observed between the inlet views of the anterior and posterior edges of S1 and the screws pierced out of the sacral canal. 3. Satisfactory closed reduction was achieved in all the 11 patients. A total of 17 screws were placed, with 12 ones into S1 and 5 ones into S2. Operation time ranged from 84 to 141 min (average, 114.4 min), fluoroscopy frequency from 69 to 101 times (average, 89.6 times), and intraoperative blood loss from 110 to 463 mL(average, 296.6 mL). No screw dislocation was observed on postoperative CT. Conclusion:As there is a difference between the inlet views of the anterior and posterior edges of S1 vertebral body, the inlet view of the posterior edge of S1 can display the posterior edge of S1 more clearly so as to improve the safety of placement of percutaneous sacroiliac screws.

BACKGROUND:The transiliac-transsacral screw placement is a clinical challenge for surgeons. This study explored a point-to-point coaxial guide apparatus assisting the transiliac-transsacral screw insertion and aimed to investigate the feasibility and accuracy of the guide apparatus in the treatment of posterior ring unstable pelvic fracture compared with a free-hand technique.METHODS:A retrospective study was performed to evaluate patients treated with transiliac-transsacral screws assisted by the point-to-point coaxial guide apparatus or free-hand technique. The intraoperative data of operative time and radiation exposure times were recorded. Postoperative radiographs and CT scans were performed to scrutinize the accuracy of screws position. The quality of the postoperative fracture reduction was assessed according to Matta radiology criteria. The pelvic function was assessed according to the Majeed scoring criteria at 6 months postoperatively.RESULTS:From July 2017 to December 2019, a total of 38 patients were included in this study, 20 from the point-to-point guide apparatus group and 18 from the free-hand group. There were no significant differences between the two groups in gender, age, injury causes, pelvic fracture type, screws level, and follow-up time (P > 0.05). The average operative time of the guide apparatus group for each screw was significantly less than that in the free-hand group (25.8 ± 4.7 min vs 40.5 ± 5.1, P < 0.001). The radiation exposure times were significantly lower in the guide apparatus group than that in the free-hand group (24.4 ± 6.0 vs 51.6 ± 8.4, P < 0.001). The intraosseous and juxtacortical rate of screw placement (100%) higher than in the free-hand group (94.4%).CONCLUSION:The point-to-point coaxial guide apparatus is feasible for assisting the transiliac-transsacral screw in the treatment of posterior unstable pelvic fractures. It has the advantages of simple operation, reasonable design and no need for expensive equipment, and provides an additional surgical strategy for the insertion of the transiliac-transsacral screw.