Evolution of patient-reported outcome measures, 1, 2, and 5 years after surgery for subaxial cervical spine fractures, a nation-wide registry study

Abstract

Background context: A longer duration of patient follow up arguably provides more reliable data on the long-term effects of a treatment. However, the collection of long-term follow up data is resource demanding and often complicated by missing data and patients being lost to follow up. In surgical fixation for cervical spine fractures, data are lacking on the evolution of patient reported outcome measures (PROMs) beyond 1-year of follow up. We hypothesized that the PROMs would remain stable beyond the 1-year postoperative follow up mark, regardless of the surgical approach.

Purpose: To assess the trends in the evolution of patient-reported outcome measures (PROMs) at 1, 2-, and 5-years following surgery in patients with traumatic cervical spine injuries.

Study design: Nation-wide observational study on prospectively collected data.

Patient sample: Individuals treated for subaxial cervical spine fractures with anterior, posterior, or combined anteroposterior approaches, between 2006 and 2016 were identified in the Swedish Spine Registry (Swespine).

Outcome measures: PROMs consisting of EQ-5D-3L_index and the Neck Disability Index (NDI) were considered.

Methods: PROMs data were available for 292 patients at 1 and 2 years postoperatively. Five-years PROMs data were available for 142 of these patients. A simultaneous within-group (longitudinal) and between group (approach-dependent) analysis was performed using mixed ANOVA. The predictive ability of 1-year PROMs was subsequently assessed using linear regression.

Results: Mixed ANOVA revealed that PROMs remained stable from 1- to 2-years as well as from 2- to 5-years postoperatively and were not significantly affected by the surgical approach (p<0.05). A strong correlation was found between 1-year and both 2- and 5-years PROMs (R>0.7; p<0.001). Linear regression confirmed the accuracy of 1-year PROMs in predicting both 2- and 5-years PROMs (p<0.001).

Conclusion: PROMs remained stable beyond 1-year of follow up in patients treated with anterior, posterior, or combined anteroposterior surgeries for subaxial cervical spine fractures. The 1-year PROMs were strong predictors of PROMs measured at 2, and 5 years. The 1-year PROMs were sufficient to assess the outcomes of subaxial cervical fixation irrespective of the surgical approach.

Keywords: Cervical spine; Fixation surgery; Patient-reported outcome measures; Subaxial spine fracture.