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[Clincial effect of 3D printing-assisted minimal invasive surgery through a small incision lateral to the rectus abdominis for pelvic fracture].

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.