Minimally invasive triangular osteosynthesis for highly unstable sacral fractures: Technical notes and preliminary clinical outcomes

Abstract

Triangular osteosynthesis involves unilateral L5 iliac posterior instrumentation combined with an iliosacral screw fixation. The aim of this study was to describe this procedure and report the preliminary clinical results in patients with unstable sacral fractures treated with minimally invasive triangular osteosynthesis (MITO). Between 2012 and 2017, 10 patients (6 men and 3 women, mean age, 50 ± 23 years) with sacral fractures were treated with MITO and were followed up for a mean of 15.0 ± 8.5 months in our institution. Classification of sacral fracture, operative time, intraoperative bleeding, timing of full weight bearing, bone union, complications, and clinical outcomes were investigated. Two cases were classified as Denis zone 1, 2 cases as zone 2, and 6 as zone 3. Four patients had Roy-Camille type 1 fracture and 2 patients had type 2. All patients underwent MITO, which involved bilateral lumbopelvic fixation and a uni/bilateral iliosacral screw with stab incisions for percutaneous fixation or central longitudinal incision. The operative time was a mean of 182 ± 64 minutes, and the amount of intraoperative bleeding was a mean of 63 ± 74 g. Full-weight bearing was initiated at a mean of 8.2 ± 2.4 weeks. Eight fractures healed; 1 patient had pulmonary embolism and 1 had implant loosening. Based on Majeed score, 8 patients had "excellent" clinical outcomes, 1 patient had a "good" clinical outcome, and the other had a "fair" clinical outcome. MITO could be less invasive on the soft tissues and be a reliable procedure for bony union. It might provide sufficient stability to accelerate the commencement of post-operative rehabilitation, even in patients with highly unstable sacral fractures.

Figure 1

Skin incision. Each incision was 3 cm long, and they were placed bilaterally 1 cm to 1.5 cm lateral to the lateral edge of the L5 pedicles and 2 cm medial to the posterior superior iliac spine (PSIS).

Figure 2

Intra-operative pictures showing percutaneous L5 pedicle and ilia screw fixation.

Figure 3

Male, 26-years-old, crush injury. A. Radiograph on admission showing a vertically displaced sacral fracture on left. B. Axial CT view of S1 on admission showing a crescent fracture on right. C. Radiograph taken after external fixation. D. Axial CT view of S1 after external fixation. The sacral fracture on the left side is reduced. E. Post-operative radiograph: posterior pelvic ring was stabilized by MITO, and anterior subcutaneous internal fixation was applied. F. Post-operative axial CT view of S1 showing appropriate insertion of a trans-sacral screw. G. Iliac screws are not bulging from the surface of posterior superior iliac crests. CT = computed tomography, MITO = minimally invasive triangular osteosynthesis. H. Radiograph at 12 months post-injury. Implants were removed.

Figure 3 (Continued)

Male, 26-years-old, crush injury. A. Radiograph on admission showing a vertically displaced sacral fracture on left. B. Axial CT view of S1 on admission showing a crescent fracture on right. C. Radiograph taken after external fixation. D. Axial CT view of S1 after external fixation. The sacral fracture on the left side is reduced. E. Post-operative radiograph: posterior pelvic ring was stabilized by MITO, and anterior subcutaneous internal fixation was applied. F. Post-operative axial CT view of S1 showing appropriate insertion of a trans-sacral screw. G. Iliac screws are not bulging from the surface of posterior superior iliac crests. CT = computed tomography, MITO = minimally invasive triangular osteosynthesis. H. Radiograph at 12 months post-injury. Implants were removed.