Objective To investigate the effectiveness of sacroiliac screw implantation assisted by three-dimensional (3D) printed faceted honeycomb guide plate in the treatment of posterior pelvic ring fracture. Methods The clinical data of 40 patients with posterior pelvic ring fractures treated with sacroiliac screw implantation between December 2019 and December 2022 were retrospectively analyzed. Among them, 18 cases were treated with sacroiliac screws fixation assisted by 3D printed faceted honeycomb guide plate (guide plate group), and 22 cases were treated with sacroiliac screws percutaneously fixation under fluoroscopy (conventional group). There was no significant difference in baseline data (P>0.05) such as gender, age, time from injury to operation, and Dennis classification between the two groups. The implantation time, frequency of C-arm X-ray fluoroscopy, frequency of guide pin adjustment of each sacroiliac screw, and postoperative complications and bone healing were recorded. Majeed score was used to evaluate the functional recovery at 6 months after operation, and CT was used to observe whether the screw penetrated the bone cortex. The deviation between the virtual position and the actual position of the screw tip, the sacral foramen, and the screw entry point was measured on the sagittal CT images of the guide plate group. Results The number of screws implanted in S1 and S2 vertebral bodies was 14 and 16 respectively in the guide plate group, and 17 and 18 respectively in the conventional group. The implantation time of each sacroiliac screw, the frequency of C-arm X-ray fluoroscopy, and the frequency of guide pin adjustment in S1, S2, and all vertebrae in the guide plate group were significantly less than those in the conventional group (P<0.05). Patients in both groups were followed up 8-48 months, with an average of 19.7 months. There was no incision infection, screw displacement, or internal fixation loosening in both groups. Callus growth was observed in all patients at 12 weeks after operation, and bone healing was achieved in all patients. The healing time ranged from 12 to 24 weeks, with an average of 15.7 weeks. No sacroiliac screw penetrated the bone cortex in the guide plate group; 2 patients in the conventional group had sacroiliac screws penetrating the bone cortex without damaging blood vessels or nerves. In the guide plate group, the deviation between the virtual position and the actual position of the screw tip, the sacral foramen, and the screw entry point were (2.91±1.01), (2.10±0.74), and (1.67±0.70) mm, respectively, with an average deviation of (2.19±1.22) mm. There was no significant difference in Majeed function evaluation between the two groups at 6 months after operation (P>0.05). Conclusion The application of 3D printed faceted honeycomb guide plate in sacroiliac screw implantation for posterior pelvic ring fracture can shorten the screw implantation time, reduce the frequency of fluoroscopy and guide pin adjustment, and reduce the risk of screw penetration through the bone cortex.
ObjectiveTo evaluate the screw-placement accuracy and technical advantages of patient-specific three-dimensional (3D)-printed drill guide-assisted C2 pedicle screw placement in bone models derived from patients with basilar invagination, and to provide evidence for clinical screw-placement strategies in high-risk craniocervical junction deformities. MethodsPreoperative thin-slice CT data from 9 patients with basilar invagination treated between June 2016 and July 2025 were used. For each patient, two 1∶1-scale 3D-printed upper cervical spine models were fabricated, and assigned to the guide-assisted group and the freehand group by computer-generated block randomization. Bilateral C2 screws were inserted by the same spine surgeon according to a standardized protocol. In the guide-assisted group, screw placement was performed in the following sequence: guide positioning, guide pin insertion, guide removal followed by enlargement drilling, tapping, and screw insertion. In the freehand group, screw placement was performed by anatomical landmark-based localization, stepwise drilling with fluoroscopic correction, enlargement drilling and tapping, and screw insertion. The primary outcomes were postoperative CT-based Gertzbein-Robbins (GR) grading of screw position and the GR grade 0/1 acceptability rate. Secondary outcomes included entry-point deviation, axial angle deviation, and the number of fluoroscopic exposures. ResultsThe two assessors showed good agreement in GR grading, with a Kappa coefficient>0.80, indicating reliable evaluations. Postoperative CT assessment showed that the overall distribution of GR grades was significantly better in the guide-assisted group than in the freehand group (P<0.05). The GR grade 0/1 acceptability rate was higher in the guide-assisted group, but the difference was not significant (P>0.05). Entry-point deviation, axial angle deviation, and the number of fluoroscopic exposures were all significantly lower in the guide-assisted group than in the freehand group (P<0.05). ConclusionPatient-specific 3D-printed drill guides can reduce geometric deviations in C2 pedicle screw placement in basilar invagination and decrease the number of fluoroscopic exposures. They show a potential advantage in improving the GR grade 0/1 acceptability rate; however, further clinical studies with larger samples are needed for verification.