Thoracic Paravertebral Blockade Reduces Chronic Postsurgical Pain in Breast Cancer Patients: A Randomized Controlled Trial

OBJECTIVE: To evaluate the effect of multilevel single-shot thoracic paravertebral blockade (PVB) on the occurrence of chronic postsurgical pain (CPSP) in patients undergoing breast cancer surgery. DESIGN: A randomized controlled trial with two parallel groups. SETTING: A tertiary hospital. METHODS: Patients scheduled for breast cancer surgery were randomized to receive either ultrasound-guided multilevel single-shot PVB from T2 to T5 (the PVB group) or nothing (the control group). Surgery was then performed under general anesthesia. Patients were followed up for 12 months after surgery. The primary end point was incidence of CPSP at six months after surgery. RESULTS: A total of 218 patients were enrolled and randomized; of these, 208 and 204 completed six- and 12-month follow-up, respectively. The incidence of CPSP at six months was significantly lower in the PVB group (12.5% [13/104]) than in the control group (24.0% [25/104], relative risk = 0.52, 95% CI = 0.28–0.96, P = 0.031). Pain scores within 48 hours both at rest and with movement were lower in the PVB group than the control group (P = 0.006 and P < 0.001, respectively). The percentages of patients with neuropathic pain were also lower in the PVB group than the control group at both six and 12 months after surgery (P = 0.016 and 0.028, respectively). Adverse events did not differ between groups. CONCLUSIONS: For patients undergoing breast cancer surgery, multilevel single-shot PVB reduces the incidence of CPSP at six months; it also improves early postoperative analgesia and reduces neuropathic pain at six and 12 months after surgery.