Area under the Curve: Analysis of Approach-Related Recovery Time in 165 Operative Cervical Spondylotic Myelopathy Patients with a 2-Year Follow-Up

Abstract

Introduction Much debate about postoperative outcomes regarding surgical approaches for cervical spondylotic myelopathy (CSM) exists in the literature with no clear evidence of superiority. We propose a novel method for assessing health-related quality of life (HRQOL) outcomes by taking into account each patient's baseline at postoperative time points and analyzing the “area under the curve” (AUC), a proxy for suffering time. Patients and Methods Post hoc analysis of a prospective, multicenter database of patients with CSM. A total of 165 patients met the following inclusion criteria: symptomatic CSM, age older than 18 years, and 2-year follow-up with modified Japanese Orthopaedic Association (mJOA) and neck disability index (NDI). The anterior approach group (AAG) ( n = 110) and posterior approach group (PAG) ( n = 55) were compared at baseline, 1 year, and 2 years for each HRQOL. This comparison was repeated with normalization, using the patient's baseline as the anchor, followed by an integration and comparison of AUC. Results and Conclusion: For the first time, AUC analysis was applied to evaluating patients with CSM. Nonnormalized HRQOLs demonstrated the AAG started higher and met better standards at all times points compared with the PAG. Normalized mJOA demonstrated the PAG actually did better at 2 years, whereas NDI suggested that the AAG did better, although this was not significant. AUC analysis further supported the superiority of the PAG, with statistical significance at 1 and 2 years' time points, suggesting that patients who undergo the posterior approach may suffer less in the first 2 years of their postoperative course.