Patient-special screw template 3D printed based on external fixation for treatment of pelvic fractures / 中华创伤骨科杂志

ABSTRACT

Objective To investigate the feasibility and accuracy of a patient-special template for antegrade pubic branch screwing and sacroiliac screwing which is 3D printed and based on the external fixation for treatment of pelvic fractures.Methods From January to April 2017,5 patients with Tile B fracture of the pelvis were treated by external fixation for damage control and closed reduction of the fracture at the first stage.They were 4 males and one female,aged from 42 to 65 years(average,54.8 years).By the Tile classification,there were one case of type B1 and 4 cases of type B2.After the CT scan data following external fixation were reconstructed and the screw trajectories were designed in 3D format,an individual template for the pelvic model was 3D printed.After the feasibility was confirmed by the preoperative operation,the patient-special template was used to insert antegrade pubic branch screws and sacroiliac screws in the surgery.The accuracy and safety of the actual screwing aided by the template were evaluated by comparing postoperative CT scans and preplanned trajectories of the screws.Results The individualized 3D printing templates based on external fixation led to precise screw placements into the superior ramus of the pubis and the sacroiliac joint.All the patient-special templates matched the external fixation well.Screw placement time ranged frown 5.1 to 17.5 min,averaging 10.3 min.The fluoroscopy frequency ranged from 6 to 16 times,averaging 9 times.The wound healed primarily.There was no damnage to the vessels or nerves.Verification of preoperative and postoperative CT scans showed an axial displacement deviation of 1.60 + 0.21 mm and an angle deviation of 2.0° ± 0.3°.The screws were basically in the bone channel without penetrating the cortex of important parts.Conclusion In the treatment of pelvic fractures,a patient-special screw template 3D printed based on external fixation can help accurate and safe insertion of the screws in a minimally invasive manner,significantly reducing the operation time and radiation exposure.