Neural correlates of postoperative pain in patients with rotator cuff tear following arthroscopic surgery: a resting-state fMRI study

This study aims to explore the neural correlates of postoperative pain and its relationship with preoperative psychological issues in patients with rotator cuff tear (RCT). Functional MRI data were collected from 78 RCT patients and 48 healthy controls (HC). Voxel-wise comparisons assessed regional homogeneity (ReHo) differences between groups. Pearson correlation and mediation analyses investigated the links between clinical data and brain changes. Additionally, machine learning using support vector machines (SVM) classified RCT patients based on postoperative pain intensity. RCT patients showed functional alterations in brain areas such as the dorsal anterior cingulate cortex (dACC), primary somatosensory cortex (SI), precuneus, and cerebellum. Increased depression levels correlated positively (r² = 0.249, P < 0.001) with ReHo in the dACC. The relationship between depression and postoperative pain intensity was mediated by dACC ReHo (indirect effect: 0.22, CI: 0.01-0.26). The combined analysis of ReHo patterns and clinical data achieved a classification accuracy of 90.4% for distinguishing RCT patients with postoperative pain. Our findings indicate a notable link between depression and postoperative pain in RCT patients, potentially linked to functional abnormalities in the dACC. Neuroimaging markers may help identify individuals at higher risk for postoperative pain.