MECHANICAL COMPLICATIONS AND LOSS OF CORRECTION IN OSTEOTOMIES OF THE THREE COLUMNS

ABSTRACT Objectives: To observe the degree of correction and postoperative evolution of the spinopelvic parameters in patients with sagittal imbalance submitted to 3-column osteotomies. Methods: Retrospective analysis of 20 cases of 3-column osteotomies in patients with evident sagittal imbalance and minimum follow-up of one year, computing evolution of radiological data as a function of time, complications and reinterventions, and classification into subgroups by preoperative spinopelvic measures and complications. The variation of measures, quantitative and categorical variables, and differences between groups were evaluated using the Wilcoxon, Spearman, Fischer’s exact test, Kruskal-Wallis and Mann-Whitney tests. Results: There was improvement of all the sagittal parameters, ideal correction in 55% of the cases and maintained until the end of the follow-up in 40% of the cases. No correlation was found between obtaining optimal correction and data or preoperative measurements. Clinical and infectious complications did not affect the maintenance of the correction. The most common mechanical complications were pseudoarthrosis-related rod fracture at osteotomy (30%) and failures at the lower fixation level (15%). There was no significant difference in the maintenance of the correction between the groups with and without mechanical complications treated. In the untreated mechanical complications there was a significantly higher radiological worsening (p<0.05) in the maintenance parameters of the curve correction (loss of 27.5 ± 14.39o vs. 3.69 ± 3.68o) and increased pelvic tilt (PT) (increase of 12.25 ± 7.27o vs. 1.13 ± 1.93o). Conclusion: The perfect correction was obtained in 55% of cases and the significant loss of correction occurred only in cases of untreated mechanical complications.