The Effect of Preoperative Ultrasound-Guided Erector Spinae Plane Block on Chronic Postsurgical Pain After Breast Cancer Surgery: A Propensity Score-Matched Cohort Study

Introduction The high incidence of chronic postsurgical pain (CPSP) has been a major issue after breast cancer surgery (BCS). The impact of regional anesthesia (RA) techniques on CPSP remains conflicting. In this propensity score-matched cohort study, we aimed to investigate the effect of preoperative single-shot erector spinae plane block (ESPB) adding to general anesthesia (GA) on the incidence of CPSP at 1 year following BCS. Methods Data of adult female patients who underwent unilateral BCS between October 2019 and June 2020 were retrospectively collected. Patients were grouped to ESPB combined with GA (ESPB + GA) and GA alone, respectively. All patients were prospectively followed up at 1 year after surgery. CPSP and neuropathic pain (NP) were measured using the brief pain inventory-short form (BPI-SF) and ID Pain scale. Eleven confounding factors were managed by propensity score matching (PSM) to achieve between-group balance. The primary outcome was the incidence of CPSP at 1 year after BCS. The secondary outcomes include proportion of NP, severity, and interference of CPSP at 1 year after surgery, acute postoperative pain, postoperative nausea and vomiting (PONV), hospital length of stay (LOS), and adverse events. Results After PSM, data for 194 patients were available for analysis (97 in each group). No significant difference in the incidence of CPSP (P = 1.000) nor percentage of patients with NP (P = 0.442) was found between the two groups. Both matched groups had similar intensity of CPSP (P = 0.547) measured by BPI-SF as well as the rates of moderate to severe CPSP (P = 1.000). A significant decrease in acute pain scores (P = 0.043) and rates of rescue analgesics demand (P = 0.042) were observed in the ESPB + GA group compared to the GA group. Multivariate logistic regression on the total study cohort showed that axillary lymph node dissection (ALND) (OR 3.541, 95% CI: 1.273-9.851, P = 0.015), radiotherapy (OR 1.918, 95% CI: 1.067-3.448, P = 0.029) and acute postoperative pain within 24 h (OR 2.109, 95% CI: 1.097-4.056, P = 0.036) were independent risk factors for the development of CPSP. Conclusions We found that preoperative single-shot ESPB was not associated with reduced incidence of CPSP at 1 year after BCS. ALND, radiotherapy, and acute postoperative pain within 24 h were independent risk factors for the development of CPSP after BCS.