Paravertebral Block and Reduction in Opioid Consumption After Mastectomy

Overview

This prospective randomized study evaluates the efficacy of paravertebral block in reducing opioid consumption during mastectomy and its impact on acute and chronic postoperative pain. Participants are women over 18 years of age, classified as ASA physical status I or II, with breast cancer and scheduled to undergo unilateral mastectomy with or without axillary lymph node dissection. Participants are randomly assigned to two groups: one receiving a paravertebral block and the other receiving multimodal analgesia. The primary outcome is intraoperative fentanyl consumption. Secondary outcomes include hypnotic and neuromuscular blocking agent consumption, the quality and time to emergence from anesthesia, adverse effects related to the paravertebral block, as well as acute postoperative pain and chronic pain assessed three months after surgery. The study aims to determine whether paravertebral block provides intraoperative opioid-sparing effects and contributes to improved postoperative pain management following mastectomy.

This was a prospective, randomized, blinded-assessor study conducted in the Department of Anesthesiology and Intensive Care at the Tunis Maternity and Neonatology Center. The study included women over 18 years of age, classified as ASA physical status I or II, with breast cancer and scheduled to undergo unilateral mastectomy with or without axillary lymph node dissection. Patients were randomly allocated immediately before entering the operating room into two groups according to a randomization table: Group A received a paravertebral block, while Group B received multimodal analgesia. In the paravertebral block group, the block was performed under ultrasound guidance on the side of the planned surgery. General anesthesia was then administered according to the study anesthesia protocol. Postoperative monitoring included close monitoring of vital signs and pain assessment at H0, H6, H12, and H24. Patients were subsequently assessed at three months to identify the presence of chronic postoperative pain and evaluate its severity using the Verbal Rating Scale and the Saint-Antoine Pain Questionnaire. The primary outcome was intraoperative fentanyl consumption. Secondary outcomes included hypnotic and neuromuscular blocking agent consumption, quality and time to emergence from anesthesia, adverse effects related to the paravertebral block, acute postoperative pain, analgesic consumption, time to ambulation, and chronic pain at three months. The study protocol included a sample size calculation based on an alpha risk of 5% and a statistical power of 90%. Statistical analysis was performed using SPSS version 20.0. The Chi-square or Fisher's exact test, Student's t-test, and Mann-Whitney U test were used according to the nature of the variables, with the significance threshold set at p \< 0.05. The study was conducted after obtaining approval from the local ethics committee and written informed consent from all participants.