Meta-Analysis
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Feb 26, 2022; 10(6): 1852-1862
Published online Feb 26, 2022. doi: 10.12998/wjcc.v10.i6.1852
Impact of adding opioids to paravertebral blocks in breast cancer surgery patients: A systematic review and meta-analysis
Meng-Hua Chen, Zheng Chen, Da Zhao
Meng-Hua Chen, Lanzhou University Medical College, Lanzhou 730000, Gansu Province, China
Zheng Chen, Department of Breast, Shandong Second Provincial General Hospital, Jinan 250021, Shandong Province, China
Da Zhao, Department of Oncology, The First Hospital of Lanzhou University, Lanzhou 730000, Gansu Province, China
Author contributions: Chen MH conceived and designed the study, analyzed the data, and wrote the paper; Chen Z and Zhao D were involved in literature search and data collection and reviewed and edited the manuscript; all authors read and approved the final manuscript.
Conflict-of-interest statement: The authors deny any conflict of interest.
PRISMA 2009 Checklist statement: The authors have read the PRISMA 2009 Checklist, and manuscript was prepared and revised according to the PRISMA 2009 Checklist.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Da Zhao, MD, Doctor, Department of Oncology, The First Hospital of Lanzhou University, No. 1 Donggang West Road, Lanzhou 730000, Gansu Province, China. zhaoda_dr@163.com
Received: July 19, 2021
Peer-review started: July 19, 2021
First decision: October 16, 2021
Revised: October 21, 2021
Accepted: January 19, 2022
Article in press: January 19, 2022
Published online: February 26, 2022
Processing time: 219 Days and 10 Hours
Abstract
BACKGROUND

Several breast cancer studies have reported the use of adjuvant opioids with the paravertebral block (PVB) to improve outcomes. However, there is no level-1 evidence justifying its use.

AIM

To elucidate if the addition of opioids to PVB improves pain control in breast cancer surgery patients.

METHODS

We conducted an electronic literature search across PubMed, Embase, Scopus, and Google Scholar databases up to October 20, 2020. Only randomized controlled trials (RCTs) comparing the addition of opioids to PVB with placebo for breast cancer surgery patients were included.

RESULTS

Six RCTs were included. Our meta-analysis indicated significantly reduced 24-h total analgesic consumption with the addition of opioids to PVB as compared to placebo [standardized mean difference (SMD) -1.57, 95% confidence interval (CI): -2.93, -0.21, I2 = 94%]. However, on subgroup analysis, the results were non-significant for studies using single PVB (SMD: -1.76, 95%CI: -3.65, 0.13 I2 = 95.09%) and studies using PVB infusion (SMD: -1.30, 95%CI: -4.26, 1.65, I2 = 95.49%). Analysis of single PVB studies indicated no significant difference in the time to first analgesic request between opioid and placebo groups (mean difference -11.28, 95%CI: -42.00, 19.43, I2 = 99.39%). Pain scores at 24 h were marginally lower in the opioid group (mean difference -1.10, 95%CI: -2.20, 0.00, I2 = 0%). There was no difference in the incidence of postoperative nausea and vomiting between the two groups.

CONCLUSION

Current evidence suggests a limited role of adjuvant opioids with PVB for breast cancer surgery patients. Further homogenous RCTs with a large sample size are needed to clarify the beneficial role of opioids with PVB.

Keywords: Opioids; Pain; Surgery; Breast cancer; Nerve block; Paravertebral block

Core Tip: The use of opioids as adjuvants for nerve blocks has been increasing. However, it is not clear if the addition of opioids to paravertebral block (PVB) improves outcomes for breast cancer surgery patients. In our first systematic review and meta-analysis, we pooled data from six randomized controlled trials assessing the role of adjuvant opioids for PVB in patients undergoing breast cancer surgery. Our results indicate that the addition of opioids to PVB has a limited role in reducing 24-h analgesic consumption, time to first analgesic request, and pain scores as compared to placebo. Further high-quality studies are required to strengthen the evidence.