Operative and non-operative treatment of symptomatic adult spinal deformity: a prospective multicenter observational study

Abstract Purpose Few prospective studies describe surgical treatment (ST) and non-surgical treatment (NST) of symptomatic adult spinal deformity (ASD). In this study, we aimed to describe short term outcomes following ST and to evaluate the feasibility and clinical course of a structured NST strategy in patients with symptomatic adult spinal deformity. Methods This is an observational multicenter study conducted in Norway, Sweden, and Japan. According to the study criteria, patients with symptomatic ASD were selected at outpatient clinics. The responsible surgeon and the patient decided on either surgery at the surgeon’s discretion or a non-surgical procedure guided by a physiotherapist. Oswestry Disability Index (ODI) was the primary outcome. Secondary outcomes included success defined as a ≥ 30% improvement in ODI score, failure (≥ 10% worsening in ODI), SRS-22, the numeric rating scale (NRS) for back and leg pain, and reoperation. Results We followed 76 ST and 16 NST patients for up to 12 months with no patients crossing over. A statistically significant improvement in ODI was only observed amongst the ST patients. The secondary outcomes measures aligned with the primary outcomes. Successful treatment (≥ 30% improvement in ODI) was achieved in 37 of 68 (54.4%), and nine out of 68 (13.2%) experienced treatment failure (≥ 10% worsening in ODI). Revision rate was 3/76 (3.9%) within 12 months. Among the 16 non-surgical patients, 1/16 (6.3%) achieved a successful result. The failure rate was 8/16 (50%) due to pain limiting the feasibility of the specific exercise protocol. Again, the secondary outcomes aligned with the primary outcomes. Conclusion A statistically significant improvement in ODI was only observed amongst the ST patients. Among the surgical patients, just over half experienced successful treatment, defined as a ≥ 30% improvement in ODI. Under the present implementation and patient selection, NST was associated with limited clinical improvement and substantial feasibility constraints due to pain, with patients, on average, experiencing a deterioration in their symptoms. This suggests that feasibility and tolerability, rather than intrinsic inefficacy of core strengthening, may explain the limited short term clinical improvement observed. The results primarily describe short-term outcomes following ST and the feasibility-limited implementation of the NST protocol, while between-group comparison should be considered exploratory. Trial registration Indication and Treatment of Adult Kyphoscoliosis (INTRAKS) Clinical Trials ID NCT04536909, protocol ID 1126, 27/04/2020. Retrospectively registered inclusion started in January 2020.