The design and application of an individualized 3D printing assisted guide plates in assisting sacroiliac screws insertion.

OBJECTIVE

Currently, the sacroiliac screws insertion still faces several challenges in the fixation of pelvic and acetabular injuries. This study was aimed to design a personalized three-dimensional (3D) printing assisted guide plates to assist sacroiliac screws insertion, so as to provide a reference for further clinical applications.

METHODS

Eight pelvic specimens (5 males and 3 females) of normal adults were used to simulate actual operation. After thin-layer CT scanning, the 3D models of pelvis were established based on the images data. Furthermore, in Mimics 17.0 software, the screw entry points and screw channels of sacroiliac screws were further simulated and designed, and the appropriate range of the posterior superior iliac spine was selected to establish and print the virtual guide plates. Then, the simulated screws insertion was performed in vitro, the pelvic specimens after screws insertion were scanned again by CT, and the effect of screws insertion was further evaluated.

RESULTS

A total of 16 sacroiliac screw guide plates were designed and printed, and 48 screws were inserted on both sides. Therein, 45 screws were completely located in the sacral vertebra, which was determined as grade 0, with an accuracy rate of 93.2%. The other 3 screws penetrated the anterior cortex or sacral canal of sacral vertebra, including 2 screws in Grade 1 (4.1%) and 1 screw in Grade 2 (2.1%). Compared with the simulated screw channels, the anterior and posterior offset angles of the cross section were (0.912 ± 0.625) ° and (0.802 ± 0.681) ° respectively, with no significant difference (p > 0.05). The upper and lower offset angles of coronal plane were (1.158 ± 0.823) ° and (1.034 ± 0.908) ° respectively, and there was no significant difference (p > 0.05).

CONCLUSIONS

3 D printing guide plates assisted sacroiliac screws insertion can enhance the stability of pelvic posterior ring fixation and assist surgeons to reduce the difficulty of operation.