Measuring Timing and Defining Phases of Reversal Surgical Effect for Cervical Myelopathy Patients Surgical Intervention

Introduction: Patient reported outcomes provide valuable information about the progress and quality of care provided. However, there is significant variation in PRO between patients and over time. It is imperative to identify stability of the metric. This study explores the Patient-Reported Outcomes Measurement Information System (PROMIS) and the Modified Japanese Orthopaedics Assosciation Scale (mJOA) stability through evaluating the reversal surgical effect for cervical myelopathy as defined by reversal of their clinical status between subsequent time point measurements.

Methods: We retrospectively assessed (mJOA) and PROMIS PH and MH scores for 200 patients receiving cervical surgery for cervical myelopathy between 2020-2022. Reversal surgical effect was defined as conversion from improvement to worsening or worsening to improving that crosses the minimal clinical important difference (MCID). Switch-point analysis was used to estimate states that define postoperative recovery over time.

Results: The reversal surgical effect at least once was reported in approximately 10% of patients when PROMIS used and 2.5% when mJOA used. After POD#630, 95% of patients stabilized in PH and MH scores (p < 0.05) and 99% of patients in mJOA score. Switch point analysis showed roughly 3 “stages” of surgical effect reversal: 1) Initial stable phase until ~POD#300 2) Improving phase between POD#300 and POD#630 and 3) a stabilization/plateau phase beyond POD#630.

Conclusion : mJOA is a more stable metric when compared to PROMIS PH and MH particularly in the first 6 months post-operatively but all metrics become increasingly stable until around 2 years. Future studies should focus on 1) the causes of measured differences in functional and quality of life recovery and 2) favoring monitoring patients up to 2 years following surgery prior to re-operation.