ABSTRACT
Objective To discuss the 3D printing modeling used to assist minimally invasive fixation with hollow screws for unstable pelvic fractures.Methods From January 2014 to January 2016,137 patients with unstable pelvic fracture received minimally invasive fixation with hollow screws and obtained complete follow-up at our department.In 65 of them,the fixation was assisted by 3D printing modeling;they were 37 men and 28 women,with an average age of 33.1 ± 4.9 years.In the other 72 cases,conventional fixation was performed without assistance of 3D printing modeling;they were 45 men and 27 women,with an average age of 32.6 ±4.7 years.The 2 groups were compared in terms of operation time,frequency of intraoperative fluoroscopy,reduction quality and curative effect.Results This cohort were followed up for 6 to 15 months (average,9 months).The 3D printing modeling group needed significantly less operation time (58.6 ± 13.4 min) and intraoperative fluoroscopy (29.3 ± 3.6 frequencies) than the conventional group (72.4 ± 12.4 min and 36.6 ± 2.8 frequencies) (P ＜ 0.05).According to the Matta scoring criteria,the quality of pelvic reduction was evaluated as excellent in 21 cases,as good in 30 cases,as fair in 13 cases and as poor in one in the 3D printing group,yielding an excellent and good rate of 78.5％ while as excellent in 22 cases,as good in 36 cases,as fair in 12 cases and as poor in 2 cases in the conventional group,yielding an excellent and good rate of 80.6％.According to the Majeed scoring criteria,the curative effect was evaluated at the last follow-up as excellent in 27 cases,as good in 26 cases,as fair in 11 cases and poor in one in the 3D printing group,giving an excellent and good rate of 81.5％ while as excellent in 30 cases,as good in 28 cases,as fair in 13 cases and as poor in one in the conventional group,giving an excellent and good rate of 80.6％.There were no statistically significant differences between the 2 groups in reduction quality or curative effect (P ＞ 0.05).No nonunion or iatrogenic neurovascular lesions happened during the follow-up period.Conclusion 3D-printing modeling is helpful for a good reduction and minimally invasive fixation with hollow screws for unstable pelvic fractures by reducing operation time and intraoperative fluoroscopy.