Correction of the pelvic incidence using a bilateral extending pelvic osteotomy: a proof of concept study

INTRODUCTION: The aim of this proof of concept human cadaver study was to quantify the effect of a bilateral extending pelvic osteotomy (BEPO) on pelvic incidence (PI) as a potential alternative for a pedicle subtraction osteotomy (PSO) in patients with severe spinal sagittal malalignment. MATERIALS AND METHODS: 10 fresh frozen human cadavers were treated with the BEPO technique. CT images were made before and after the osteotomy and pure sagittal images were created on which PI was measured. RESULTS: The mean pre-osteotomy PI was 47.9° (range 36.4–63.9) and the mean post-osteotomy PI was 36.5° (range 22.1–54.4). The mean correction was − 10.4° with a range of − 8.4° to − 17.3° (p = 0.03), which resulted in a mean decrease of 23% in the PI (range 16–42). CONCLUSIONS: There was a feasible and effective correction of PI using the BEPO technique on the os ilium. This was a preliminary cadaveric study. No conclusions could be made on global sagittal alignment. We postulate that an extending osteotomy of the ilium could be a potential alternative for a PSO reducing the complexity of spine surgery in patients with severe spinal sagittal malalignment.