Dear Editor,
We read with great interest the article titled ‘Hemihepatic versus total hepatic inflow occlusion for laparoscopic hepatectomy: a randomized controlled trial’ published in the recent issue of the International Journal of Surgery1. This study quantified the relative efficacy and safety of video-assisted thoracic surgery (VATS) patients receiving 18 different regional analgesic interventions and attempted to find an optimal approach that could be used as a reference for clinical medicine. The authors concluded that thoracic paravertebral block showed superior analgesia, ranking highest in reducing pain scores and lowering opioid consumption in the early postoperative period. This study provides available clinical evidence on the choice of the best regional analgesia technique for patients undergoing VATS. We would like to revisit this article from the following three perspectives to further refine this important study.
The authors searched the target articles in the following four databases: Embase, Cochrane Library, PubMed, and Web of Science citation index. Nevertheless, the search of English databases should be expanded appropriately, and other commonly used databases including PsycINFO, Google Scholar, Scopus, and ClinicalTrial.gov should also be considered. In addition, the authors emphasized that the search process had no language limitation. Therefore, some commonly used Chinese databases such as Wanfang and China Knowledge Network should also be searched comprehensively.
Secondly, we believe that the authors did not fully follow the inclusion criteria they set in the identification of studies. The authors clearly emphasized the inclusion of only randomized controlled trials in the text, so why include a nonrandomized prospective study2 and a retrospective study3 in the analysis? In addition, we found that the authors did not accurately assess the risk of bias in the included studies. For example, in the study of Dikici et al.4, the method of randomization was not described in detail in the text, thus the risk of randomization should be unknown; Dikici et al. simply stated in the text that the anesthesiologist was blinding, but this does not mean that the patients were also blinded, so the risk of performance bias was high. For another example, Fiorelli et al.5 emphasized that blindness was limited to anesthesiologists, but the authors considered performance bias to be a low risk. Therefore, we believe that the authors should reassess the risk of bias in all studies.
Another worrying drawback is the high heterogeneity of the pooled outcomes in pair-wise analyses, which may affect the accuracy of the conclusions. The heterogeneity of outcomes is mainly caused by a combination of various confounding factors including different designs among studies, different patient characteristics, diversity in drug doses, differences in surgical and anaesthetic techniques and inconsistent follow-up time points, which are inevitable to some extent. However, we suggest that the authors use inverse variance heterogeneity models to validate the true effect sizes of the outcomes. The inverse variance heterogeneity model can solve the known problems of underestimating statistical error and false overconfidence estimation using the random effect model. In addition, although the authors included 38 randomized controlled studies, the number of studies and sample size on which most of the pooled outcomes were based was limited. Therefore, it was difficult for the authors to reveal the sources of heterogeneity in the results through subgroup analysis and meta-regression analysis. More high-quality randomized controlled trials are needed in the future to further elucidate the optimal regional analgesia technique in patients with VATS.
Ethical approval
Not applicable.
Sources of funding
1. 2019 Gansu Provincial Hospital in-hospital fund project-general project, No. 2019-375.
2. 2022 Gansu Provincial Hospital Cultivation Plan, Project Number: ZX-62000001-2022-291.
3. Provincial science and technology project of Gansu Provincial Science and Technology Department, project number: 21JR7RA602.
Author contribution
The author read and approved the final version of the letter to the Editor.
Conflicts of interest disclosure
There are no conflicts of interest.
Research registration unique identifying number (UIN)
Not applicable.
Guarantor
Ruhuang Si.
Provenance and peer review
Commentary, internally reviewed.
Footnotes
Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article.
Published online 4 May 2023
Contributor Information
Bingqiang Ma, Email: edustusoso@163.com.
Ruohuang Si, Email: rsrsopp@163.com.
References
- 1.Peng Y, Yang Y, Chen K, et al. Hemihepatic versus total hepatic inflow occlusion for laparoscopic hepatectomy: a randomized controlled trial. Int J Surg 2022;107:106961. [DOI] [PubMed] [Google Scholar]
- 2.Baldinelli F, Capozzoli G, Pedrazzoli R, et al. Are thoracic wall blocks efficient after video-assisted thoracoscopy surgery-lobectomy pain? a comparison between serratus anterior plane block and intercostal nerve block. J Cardiothorac Vasc Anesth 2021;35:2297–2302. [DOI] [PubMed] [Google Scholar]
- 3.Xia Z, Depypere L, Song Y, et al. Uniportal thoracoscopic wedge resection of lung nodules: paravertebral blocks are better than intercostal blocks. Surg Innov 2020;27:358–365. [DOI] [PubMed] [Google Scholar]
- 4.Dikici M, Akesen S, Yavaşcaoğlu B, et al. Comparison of intraoperative and post-operative effects of serratus anterior plane block performed with ultrasound and infiltration block in patients undergoing video-assisted thoracoscopic surgery. Agri 2022;34:23–32. [DOI] [PubMed] [Google Scholar]
- 5.Fiorelli S, Leopizzi G, Menna C, et al. Ultrasound-guided erector spinae plane block versus intercostal nerve block for post-minithoracotomy acute pain management: a randomized controlled trial. J Cardiothorac Vasc Anesth 2020;34:2421–2429. [DOI] [PubMed] [Google Scholar]