Defining Substantial Clinical Benefits of PROMIS Pain Interference and Physical Function in Patients Undergoing Lumbar and Thoracolumbar Spine Surgery.

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

This study aims to define Substantial Clinical Benefit (SCB) thresholds for PROMIS physical function (PF) and pain interference (PI) in lumbar or thoracolumbar spine surgery population.

SUMMARY OF BACKGROUND DATA

Patient-reported outcome measures (PROMs) are widely used in spine surgery to assess treatment efficacy. SCB is a relatively new concept that represents a substantial improvement perceived by the patient.

METHODS

This is a prospective study that included adults aged 21-85 years, undergoing lumbar/ thoracolumbar surgery for degenerative spine disease, and reporting at least 3/10 back or leg pain on a numeric rating scale. PROMs including Oswestry Disability Index, PROMIS PF, and PROMIS PI were collected preoperatively and at one year postoperatively. The North American Spine Surgery Patient Satisfaction (NASS) Index was collected one year postoperatively. SCB thresholds of absolute and percentage changes were calculated using anchor-based methods with ODI and NASS index as anchors. ROC analysis was used to determine optimal SCB cutoffs.

RESULTS

We included 137 patients. Using a fixed 19-point reduction in ODI as an anchor yielded SCB thresholds of 6.8 and 11.3 points for PROMIS PF and PI respectively. When using a dynamic anchor based on preoperative disability (50% ODI improvement), SCB thresholds were defined as achieving 18 and 27% of maximum possible improvement for PROMIS PF and PI respectively. Using NASS index, thresholds were 11 points or 24% for PROMIS PF, and 11.2 points or 21% for PROMIS PI. ROC values ranged from 0.81 to 0.9, with the dynamic ODI anchor cutoffs demonstrating the best discrimination.

CONCLUSION

Our study is the first to define SCB thresholds for PROMIS PF and PROMIS PI using both fixed and dynamic cutoffs based on preoperative disability in lumbar and thoracolumbar patients. These thresholds will help in patient counseling and outcome evaluation for spine surgery research.