Minimally Invasive 360° Fusion Using a Combination of INFIX and Minimally Invasive Spinopelvic Fixation by Intraoperative Computed Tomography Navigation for Unstable Pelvic Ring Fracture: A Technical Note

Abstract

Objective: Fluoroscopy is often used in the surgery of unstable pelvic ring fractures, and improved safety in implant placement is an issue. An anterior subcutaneous pelvic fixator (INFIX) combined with a percutaneous screw has been reported to be a minimally invasive and effective surgical technique for unstable pelvic ring injuries. However, although percutaneous screw fixation is minimally invasive, its indications for fracture fixation and fractures with large fragment displacements in the vertical plane remain controversial. Therefore, this technical note aims to describe a new technique for unstable pelvic ring fractures.

Methods: We describe a 360° fusion of the pelvic ring to treat unstable pelvic ring fractures, including vertical shear pelvic ring fractures, using an intraoperative CT navigation system. Seven patients were treated with 360° fusion for type C pelvic ring fractures. In surgery, after reducing the fracture with external fixation, intraoperative CT navigation is used to perform a 360° fusion with INFIX and minimally invasive surgical spinopelvic fixation (MIS-SPF). We will introduce a typical case and explain the procedure.

Results: A 360° fixation was performed, and no perioperative complications were noted. The mean blood loss was 253.2 ± 141.0 mL, and the mean operative time was 224.3 ± 67.4 min. In a typical case, bone union was obtained 1 year after surgery, and we removed all implants.

Conclusions: MIS-SPF has a strong fixation force and helps reduce fractures' horizontal and vertical planes. In addition, 360° fusion with intraoperative CT navigation may help treat unstable pelvic ring fractures.

Keywords: 360° fusion; Anterior subcutaneous pelvic fixator; Intraoperative CT navigation; Minimally invasive surgical spinopelvic fixation; Pelvic ring fracture.

Fig. 1

Measurement of the pelvic deformity index (PDI), vertical displacement (VD), and pubic symphyseal width (PSW) using 3D CT reconstruction. VD was measured from the top of the iliac crests, from a line perpendicular to the L5 reference line. X or Y is the diagonal length from the inferior sacroiliac joint (iliac side) to the inferior aspect of the teardrop. PDI = absolute (X − Y)/(X + Y). PSW was the largest width of the symphysis pubis.

Fig. 2

Preoperative plain radiograph (A) and 3D CT reconstruction (B) of pelvic ring fracture indicated a type C1.3 fracture with Denis II fracture.

Fig. 3

Anterior screw insertion method using intraoperative CT navigation. (A) Navigated pedicle probe and (B) navigated CD Horizon® Ballast screw.

Fig. 4

Intraoperative obturator outlet fluoroscopic view showing teardrop for the anterior screw.

Fig. 5

After INFIX with external fixation. Intraoperative x‐rays before (A) and after (B) external fixation indicate posterior vertical dislocation (arrow).

Fig. 6

Minimally invasive surgical spinopelvic fixation (MIS‐SPF) technique for unstable pelvic ring fractures with vertical shear. Navigation‐assisted (A) percutaneous pedicle screws (PPS) insertion and (B) rod insertion; (C) distraction technique between the gripper and offset connector; (D) surgical field after distraction; (E) fluoroscopic image after distraction (arrow); (F) fluoroscopic image after lateral compression (arrow), and connection of the rod to the lower pairs of screws on both sides. From (E) to (F): dislocation of the sacroiliac joint has been reduced due to the lateral compression force applied to the iliac screw.

Fig. 7

The postoperative (A) pelvic anteroposterior (AP) view and (B) 3D CT reconstruction of the pelvic ring fracture confirmed the reduction of the vertical shear dislocation and pubic symphysis dissociation of the fracture. (C) There is no deviation of each anterior (dashed arrow) and posterior screw (solid arrow) in the obturator outlet view by 3D CT reconstruction.

Fig. 8

Postoperative plain radiograph 1 year after surgery. (A) Pelvic anteroposterior (AP) view; (B) pelvic inlet view; and (C) pelvic outlet view. Postoperative plain radiograph 1 year after surgery showed bone union, and all implants were removed.