Longitudinal cumulative outcome after adult spinal deformity surgery

Backgrounds: The primary aim of this study was to investigate how the level of disability, pain, and health-related quality of life (HRQL) change during comprehensive longitudinal follow-up period after adult spinal deformity (ASD) surgery. A secondary aim was to evaluate the prevalence and time of revision surgeries due to mechanical complications. Methods: Altogether 138 ASD patients were operated at Central Finland Central Hospital between 2007 and 2019. Patients’ HRQL was followed up with the following patient-reported outcome questionnaires; the Oswestry Disability Index (ODI), the Pain Visual Analogue Scale (Pain-VAS) and the Scoliosis Research Society questionnaire version 30 (SRS-30). The operation criterion was severe symptomatic sagittal and/ or coronal spinal deformity. Results: Altogether, 128 patients were included. The ODI (p < 0.001), the leg Pain-VAS (p < 0.001), and the back Pain-VAS (p < 0.001) continued to improve up to five to seven years after ASD surgery. The achieved level remained significant at follow-up (p < 0.001). The improvement that was achieved in the first year in the SRS-30 domains did not deteriorate notably at longitudinal follow-up. Ten years cumulative prevalence of mechanical failure after surgery was 24% (95% CI: 12–44%). Conclusions: Patient-reported outcomes improve up to five to seven years after ASD surgery and seemed to remain significantly better than preoperative scores at longitudinal follow-up. The majority of the mechanical complications cumulated over the first two years of follow-up.