Pain modulation in amputees: Exploring conditioned pain modulation and its influencing factors on amputated and non-amputated sides: A cross-sectional study

Abstract

Background

Amputation leads to significant physical, psychological, and emotional challenges, with chronic pain being among the most debilitating outcomes. Conditioned Pain Modulation (CPM) is a key mechanism for understanding pain modulation reflecting the central nervous system’s capacity to regulate pain.

Objective

This study aimed to evaluate CPM in amputees, comparing CPM between the amputated and non-amputated sides, and to identify factors influencing CPM in this population.

Method

Eighty-six amputees participated in the study. Sociodemographic and pain-related variables, including age, occupation, smoking status, pre-amputation pain duration, phantom limb pain, and pressure pain threshold, were assessed. Multiple linear regression models were performed to explore factors associated with CPM on both sides, with additional t-tests to compare CPM values between sides.

Results

The multivariate model for the amputated side explained 26.3% of CPM variability, with significant associations found for pre-amputation pain duration and retirement status, as well as PPT mean of the amputated side, smoking, and phantom limb pain and age. In contrast, the non-amputated side model explained 26.5% (Adjusted R-squared) of the variability, with the following significant variables: duration of pre-amputation pain (negative correlation), smoking history, phantom limb pain (negative correlation), and frequency of telescoping sensation (negative correlation). There were no significant differences in CPM between amputated and non-amputated sides (p > 0.05).

Conclusion

The findings suggest that CPM on the amputated side is more influenced by pain experience and sociodemographic variables, while the non-amputated side shows less variability and is more resilient to these influences.