Background: The aim of this study was to identify the incidence of early mechanical failure in the first post-surgical year in patients who had undergone spinal surgery and to assess the related risk factors. Methods: A retrospective observational study was conducted examining all patients who consecutively underwent arthrodesis surgery. The incidence of postoperative mechanical failure during the first year was calculated as the primary outcome. Results: A total of 237 patients were identified for statistical analysis. The median age of the group of patients was 47 years (IQR of 44), and 66.6% were female. The incidence of mechanical failure in the first postoperative year was 5.1% overall, with 12 events, and the median time between surgery and the need for revision surgery was 5 months (IQR = 7.75). ASA score (OR = 2.39; p = 0.134), duration of the surgical procedure (OR = 1.27; p = 0.118), and inability to walk at discharge (OR = 7.86; p = 0.007) were independent risk factors associated with the mechanical failure. Conclusions: A higher ASA score and longer duration of surgery were risk factors for mechanical failure in the first year in patients who had undergone spinal surgery and must be carefully considered when planning spinal surgery. Early recovery of ambulation must be encouraged to prevent mechanical failure.

PURPOSE: The aim of this study was to identify the incidence of early mechanical failure in the first post-surgical year in patients who had undergone spinal surgery, and to assess the related risk factors. METHODS: Retrospective observational study of a prognostic cohort was conducted at an orthopaedic hospital, examining all patients with spine degenerative disease who consecutively underwent arthrodesis surgery between March 2018 and March 2019. The incidence of postoperative mechanical failure during the first year was calculated as primary outcome; the time between the date of the implant surgery and diagnosis of the mechanical failure was calculated as secondary outcome. RESULTS: A total of 237 patients were identified for statistical analysis. The median age of the group of patients was 47 years (IQR of 44), and 66.6% were female. The incidence of mechanical failure in the first postoperative year was 5.1% overall with 12 events and the median time between surgery and the need for revision surgery was 5 months (IQR=7.75). ASA score (OR= 2,39; p=0.134), duration of the surgical procedure (OR=1,27; p=0,006) and inability to walk at discharge (OR=7,86; p=0,072) were independent risk of factor associated with the mechanical failure. CONCLUSION: Higher ASA score and longer duration of surgery are risk factors for mechanical failure in the first year in patients who had undergone spinal surgery and must be carefully considered when planning spinal surgery. During hospitalization, recovery of ambulation must be encouraged to prevent mechanical failure. All these factors are useful in identifying patients with a closer follow-up is needed.