Development of More Precise Measurement to Predict Pain 1 Month Postoperatively Based on Use of Acute Postoperative Pain Score in Patients With Distal Radial Fracture.

BACKGROUND

A method for modeling the acute pain trajectory using the simple linear fit of an individual's pain intensity scores after surgery was developed and affords more precise measurement than conventional pain assessment. However, the method has the disadvantage of using only the slope without considering the intercept. The purpose of this study was to verify our modification of the pain trajectory model including slope and intercept and to identify clusters.

METHODS

The pain intensity was measured in 60 patients after surgery, and we calculated their pain trajectories. The pain trajectory normally resolves in intensity over a period of days, and the linear fit of an individual patient's pain intensity score defines the trajectory. In this simple linear model (x axis, days; y axis, pain intensity), each patient's trajectory has the slope and the intercept. A multiple regression analysis model known as structural equation modeling was used to predict postoperative pain at 30 days after surgery. Finally, we performed hierarchical cluster analysis using the pain trajectory.

RESULTS

The slope and intercept model was the best fit among the models. Based on cluster analysis results, we created 4 pain trajectory groups (slope and intercept).

CONCLUSION

Our results suggest that the pain trajectory using the slope and intercept is quite useful for predicting postoperative pain at 30 days after surgery. Additionally, patients were classified into 4 groups using the slope and intercept. By considering both the slope and intercept, clinicians may be able to detect the risk for prolonged pain earlier than other methods.