Figure 1.

Photographs demonstrating the design and 3D printing of the external guide template. (a) Two nonparallel external fixation pins were inserted into the patient's iliac crest as markers for the design of the template. (b) 7.0 mm diameter cylinders were employed to simulate the tracks of S1, S2 iliosacral, or superior ramus screws. (c) The external template was designed based on the marker pins and virtual screw guide pins (2.5 mm diameter KW), and the template was cut into 2 pieces (shown in different colors) to facilitate the smooth sticking of the external fixation pins during the operation. (d) “Plum blossom” like guide holes (black arrow) could facilitate the microadjustment of the KW. (e) The 3D printed external template.