Abstract: Objective To evaluate the clinical effect of 3D printing-assisted minimal invasive surgery on pelvic fracture by plate
internal fixation through a small incision lateral to the rectus abdominis. Methods This retrospective study was conducted
among 50 patients with pelvic fracture undergoing anteromedial plate internal fixation between September, 2013 and June,
2015. Thin-layer computed tomography scan data of the patients were input into Mimics software in DICOM format for 3D
editing and virtual surgery before the operation. The pelvic model was created by 3D printing. Simulated operation was
performed to design the optimum location of the plate screw, prelflex of the plate, screw length measurement and screwing
approach. Diaplasis and internal fixation were performed through the extraperitoneal space with a small incision lateral to the
rectus abdominis. Matta standard was employed for diaplasis evaluation, and Majeed assessment was used for function
evaluation 6 months after the operation. Results According to Matta standard, excellent and good diaplases were achieved in
96% of the cases, as compared with 94% according to Majeed assessment. Radiographic examination showed a good
consistency between the internal fixation and simulated operation. No screw entry into the hip joint cavity occurred in these
cases. The mean operation time was 127 min in these cases with a mean intraoperative blood loss of 728 mL and a mean
incision length of 8.4 cm. Based on the postoperative VAS score, 12 patients reported severe pain, 28 reported moderate pain
and 10 reported mild pain. All the patients were advised for early functional exercise after the operation and clinical healing
was achieved in a mean of 8 weeks. Conclusions 3D printing with simulated operation can improve the accuracy and safety of
the operation. Preoperative simulation of plate preflex and screw length measurement can shorten the operation time. A small
incision lateral to the rectus abdominis allows minimally invasive operation for pelvic fractures.