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. TRIAL REGISTRATION: The study was registered in the Chinese Clinical Trial Registry (ID: ChiCTR2000038464, date of registration: September 23, 2020).