Background To compare the clinical efficacy of unilateral unstable sacral fractures (USFs) involving the lumbosacral region treated with and without robot-aided triangular osteosynthesis (TOS). Methods Patients of the unilateral USF combined with the ipsilateral lumbosacral junction injury (LSJI) treated with TOS were retrospectively analyzed and divided into two groups: the robot group (TOS with robotic assistance) and the conventional group (TOS with open procedure). Screw placement was assessed using the modified Gras criterion. Patients were followed up with routine visits for clinical and radiographic examinations. At the final follow-up, clinical outcomes were recorded and scored using the Majeed scoring system. Results Eleven patients in the robot group and seventeen patients in the conventional group were recruited into this study. Significant differences in surgical bleeding (P < 0.001) and fluoroscopy time (P = 0.002) were noted between the two groups. Operation time (P = 0.027) and fracture healing time (P = 0.041) was shorter in the robot group. There was no difference in postoperative residual displacement between the two groups (P = 0.971). According to the modified Gras criterion, the percentages of grade I for sacroiliac screws in the two groups were 90.9% (10/11) and 70.6% (12/17), and for pedicle screws were 100% (11/11) and 100% (17/17), respectively. The rate of incision-related complications was 0% (0/11) in the robot group and 11.8% (2/17) in the conventional group. Statistical differences were shown on the Majeed criterion (P = 0.039), with higher scores in the robot group. Conclusion TOS with robotic assistance for the treatment of unilateral USFs combined with ipsilateral LSJIs is safe and feasible, with the advantages of less radiation exposure and fewer incision-related complications.

BackgroundTo compare the therapeutic effects of triangular osteosynthesis (TOS) with and without robotic assistance for unilateral unstable sacral fractures (USFs) involving lumbosacral junction injuries (LSJIs).Methods Patients with unilateral USF involving ipsilateral LSJI fixed with TOS were retrospectively analyzed and divided into two groups: the robot group (TOS with robotic assistance) and the conventional group (open reduction and TOS fixation). Screw position was assessed with Gras criterion. Patients were followed up with routine visits for clinical and radiographic examination. Clinical function outcome was recorded and scored with Majeed scoring system at last follow-up.Results Eleven patients in the robot group and seventeen patients in the conventional group were recruited into this study. Significant differences in surgical bleeding (P<0.001) and fluoroscopy times (P=0.002) were noted between the two groups. Operation time (P=0.027) and fracture healing time (P=0.041) was shorter in the robot group.There was no difference on postoperative residual displacement between the two groups (P=0.971). According to the modified Gras criterion, the percentages of grade I on sacroiliac screws were 90.9% (10/11) and 70.6% (12/17), and that on pedicle screws were 100% (11/11) and 100% (17/17), respectively. The rate of incision-related complications was 0% (0/11) in the robot group and 11.8% (2/17) in the conventional group. Statistical difference was shown on the Majeed criterion (P=0.039), with higher scores in the robot group.ConclusionTOS with robotic assistance for the treatment of USFs involving LSJIs was minimally invasive and feasible, with the advantages of decreasing fluoroscopy and incision-related complications.

Background Despite their seldom appearance, unstable bilateral sacral fractures are severe injuries and always cause surgical management difficulties. Lumbopelvic fixation is reliable for rigid method, but wound-related complications with open procedure have been relatively common. Methods Data of 8 patients with unstable bilateral sacral fractures who were treated surgically in our institution from March 2016 to April 2019 were retrospectively analyzed. There were 5 men and 3 women with an average age of 38.5 years (range, 19-60years). According to the sharp of sacral fractures, there were one case with simple bilateral vertical fracture lines, 6 cases with “U” and one case with “H”. According to Roy-Camille classification, 7 of 8 sacral fractures involving sacral canal were classified with type I 2 cases, type II 4 cases and type III 1 case. Three-dimensional(3D) printing pelvis were performed to simulate lumbopelvic and sacroiliac screw fixation for preoperative planning. Eight bilateral sacral fractures were treated with minimally invasive lumbopelvic fixation under robotic guidance. Results The screws inserted with robotic assistance were exposed to radiation with an average of 41.6±10.2 times (range, 27–53 times) intraoperatively. The total fluoroscopy time was 32–59 s, and the average fluoroscopy time for each screw was 4.2±0.6s. According to modified Gras classification of screw position, there were Grade I in 7 cases and Grade II in one case (left S1 screw). The average operation time was 150.6 min (range, 95-220 min), and intraoperative blood loss was 87.5 ml (range, 60-120 ml). Eight patients were followed up consecutively for at least 12 months, with an average of 17.0 months (range, 12–24months). No patient suffered a neurovascular injury intraoperatively. There were no incision-related complications. All fractures healed with an average time of 4.2 months (range, 3–10 months). According to Majeed functional assessment investigation, the mean score was 88.4 points (range, 78–98 points), which were graded as follows: 5, excellent and 3, good. Conclusion Under robot guidance, minimally invasive lumbopelvic fixation for unstable bilateral sacral fractures is a feasible option with the advantages of accuracy, less radiation and safety. Simulated operation with 3D printing for preoperative planning can simplify the actual surgery.