Comparing erector spinae plane (ESP) and thoracic paravertebral (TPV) block analgesic effect after elective video-assisted thoracic surgery: a randomized, multiple-blinded, non-inferiority trial

Introduction

Video-assisted thoracic surgery (VATS) is regarded as the gold standard minimally invasive surgical technique for anatomic and non-anatomic lung resections (1). When compared to open thoracotomy, VATS has the advantages of a quicker recovery, less intense perioperative discomfort, and lower postoperative morbidity (2-4). However, pain following VATS impedes deep breathing, limiting lung function and coughing, which might lead to a higher risk of cardiorespiratory problems (>15%), a longer recovery period, and higher expenses (2). Within the enhanced recovery after surgery (ERAS) perspective, and not only, it is crucial to identify the correct analgesic methodology to prevent factors that delay postoperative recovery as well as issues that cause complications (5,6). Sometimes some of these complications are related to opioid use, so regional anesthesia for pain management is strongly recommended (7). The optimal perioperative analgesic strategy after VATS remains debated (8). Thoracic epidural analgesia (TEA) is regarded as the gold standard analgesic approach (9). The drawbacks of epidural analgesia include its intrusive nature, the requirement for bladder catheterization owing to temporary impairment of bladder function, the possibility of uncommon but serious neurologic consequences, and failure rates as high as 30% (10).

In the era of ERAS protocols, a less invasive approach to post-operative pain management is an increasingly interesting topic in the field of clinical research. Thoracic paravertebral (TPV) block has fulfilled this research (8) as it has proven to be very often useful in pain management with less hemodynamic resentment than TEA (11-17). Specific-shot or continuous TPV may be a good substitute for TEA or systemic opioid administration, since there is no evidence to support a specific regional method that is better for relieving pain following VATS (8,18). Although there is nowadays a widespread use of ultrasound techniques, it is important to emphasize that performing a TPV requires advanced expertise to minimize possible complications due to the proximity of structures such as the pleura and epidural space (19,20). Not least in importance, it is useful to remember that TPV is a deep blockade that must be performed with the same caution and pharmacological suspension as TEA (21). As mentioned above, the trend in surgical procedures is increasingly oriented towards less invasiveness, so it is useful that anesthesiologic techniques also pursue this goal. The erector spinae plane (ESP) block is one example of an ultrasound-guided interfacial plane block that has been reported recently in VATS (22,23). The goal of this block is to inject local anesthetics in an interfacial plane where peripheral nerves pass, away from the spinal cord. While the population is small, ESP block is thought to be technically simpler to execute than TEA (24) and appears to be a clinically safe alternative regional anesthesia approach for thoracic surgery, such as VATS. Among the many other wall blocks, ESP is of particular importance because of its proximity to the paravertebral space without acquiring the contraindications of an anesthesia technique such as TPV. In addition, it blocks both the dorsal and ventral branches (25), sometimes providing minimal analgesia, even visceral analgesia. The mechanism of operation is not entirely clear (26,27).

Currently, there is growing information in the literature regarding the use of these infiltrative blocks, so we thought it would be useful to augment the data with a randomized, non-inferiority, multiple-blind study where we compared ESP with TPV in post-operative analgesia in VATS with primary outcome opioid consumption. We present this article in accordance with the CONSORT reporting checklist (available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-1548/rc).

Methods

The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). The study, under risk category A, according to ClinO, Art. 61 (clinical trial with intervention with minimal risks and burdens, investigating neither therapeutic products, nor devices, nor transplant products) was approved by the ethics committee of Ticino (No. 022-01759, Rif CETI 4206) and was registered on https://clinicaltrials.gov with the ID NCT05798585. Informed consent was taken from all the patients.

This study was conducted at the Regional Hospital of Bellinzona and Valli (ORBV). This is a tertiary regional hospital performing general thoracic surgery with an operating volume of over 350 procedures/year.

Patients over 18 years of age undergoing elective VATS lung resection at ORBV were evaluated to be included during the pre-anesthetic assessment. After careful explanation of the study procedures, written informed consent was signed. Patients with inability to consent, contraindications to standard care, or factors that can cause bias in interpretation and with absolute contraindications to the regional anesthesia techniques studied were excluded.

Study protocol and standard of care

Patients screened for study participation were scheduled for elective surgical procedures, performed with VATS approach (intention to treat). Patients who agreed to take part in the study were randomized in a 1:1 ratio by a computer-generated random number sequence through the 5dBase software system on the day of the surgical procedure to receive, after general anesthesia, either an ESP block with local anesthetic and a TPV block with saline (Anest ESP) or an ESP block with saline and a TPV block with local anesthetic (Sham ESP) at T5 according to a computer-generated random list.

A stratification was also performed according to the type of surgery the patient underwent: major and minor, based on whether the resection was anatomical or extra-anatomical. The rational for this subdivision is based on different average duration that the two groups of procedures usually imply, and consequently on the surgical trauma caused to the chest wall. The study coordinator, attending anesthesiologist, surgeons, data collection residents, and patients were all blinded to the treatment group assignment.

Both blocks were performed, under ultrasound guidance, in lateral decubitus after standardized general anesthesia was performed and the lung to be operated on was excluded from ventilation to further reduce the risk of complications.

VATS procedures were performed either by broad-certified thoracic surgeons or by supervised residents. Surgical approach was 3-port VATS with 7 to 4 cm incisions depending on the type of resection, with no use of rib spreader. A single chest drain was placed at the end of procedures. Anatomical lung resections included lobectomies and segmentectomies with lymphadenectomy, in case of lung cancer, whereas extra-anatomical lung resections included wedges, bullectomies, and lung volume reduction surgery. In case of intraoperative conversion to open thoracotomy, the patient was withdrawn from the study and a TEA was placed at the end of the procedure.

Postsurgical care included initial monitoring in the high-dependency unit and subsequent transfer to a dedicated ward when clinically indicated. Where pain, assessed by NRS numeric scale ≥8 at rest, or otherwise not tolerable (as 10 after coughing), was evident at the time of awakening and post-operative monitoring, we adopted as an escape strategy the placement of a peridural catheter for continuous analgesia. Post-operative pain management was standardized with the administration of paracetamol every 6 hours and ketorolac every 8 hours, as well as patient-controlled intravenous morphine. Standard pathways of care included early mobilization and respiratory physiotherapy.

Demographic data, smoking and medical history, and chronic use of non-steroidal anti-inflammatory drugs (NSAIDs) were recorded. Required and obtained morphine boluses, numeric rating scale (NRS) at rest and after cough, hemodynamic and respiratory parameters, episodes of nausea or urinary retention were collected to assess the course of post-operatory period. Postoperative cardiopulmonary complications were recorded according to the European Society of Cardiothoracic Surgery definitions (28).

Perioperative management and ultrasound-guided nerve blocks

Perioperative preparation time and procedures for both study groups were consistent. Patients were monitored, including intermittent non-invasive blood pressure measurement, continuous electrocardiographic (ECG) recording, and continuous transcutaneous oxygen saturation. Anesthesia induction and maintenance protocols were standardized according to the centers’ clinical practice. After induction of general anesthesia, each patient in the study group received either an ESP block and a paravertebral block with local anesthetic and saline solution at T5 level according to the randomization group. The calculated volume per injection was 0.4 mL/kg [ideal body weight (IBW)]. The local anesthetic used was ropivacaine 0.375%. Anesthesia was made using a special needle for ultrasound-guided blocks (REGANESTH unoplex, TRANSMED, Bad Wünnenberg, Germany) with a length of 50 or 80 mm, depending on the patient’s anatomy. During the perioperative period both groups received intravenous non-opioid analgesics (paracetamol 1 g, ketorolac 30 mg, mephameson 0.1 mg/kg, and morphine 0.1 mg/kg). At the end of surgery, patients were monitored in the recovery room or intensive care unit, depending on the type of surgery they underwent (major surgery in intensive care unit).

The monitoring of the patients for the collected data lasted 48 hours after surgery. We measured as primary outcome:

• Cumulative dose of rescue opioids consumed after 24 and 48 postoperative hours. Each patient received rescue morphine on-demand, via an intravenous patient-controlled electronic pump.

And as secondary outcomes:

• Pain scores at 4, 8, 24, and 48 hours, measured on an NRS;
• Cardio-pulmonary complications (28);
• Procedure time and immediate complications (29,30);
• Need for rescue anti-nausea medication (dosage, doses, and time points);
• Episodes of vomiting occurred in the first 48 hours postoperatively;
• Episodes of urinary retention in the first 48 hours postoperatively;
• Need for epidural catheter for ineffective analgesia;
• Length of stay (LOS) in hospital.

Statistical analysis

The study was powered as a non-inferiority study for postoperative opioid consumption starting from a study (31) where the opioid consumption in VATS after 24 hours with TPV could be deduced by converting oxycodone consumption to morphine equivalents (morphine equivalent dose). If there was truly no difference between the standard and experimental treatment, then 18 patients were required to be 90% sure that the lower limit of a one-sided 95% confidence interval (or equivalently a 90% two-sided confidence interval) would be above the non-inferiority limit of 5 mg.

Considering the possibility of dropout, conversion to thoracotomy resulting in the need for peridural catheter placement, and the need for peridural catheter as escape therapy for ineffective analgesia we decided to enroll 50 patients (32).

To address possible confounders on primary outcomes, we performed a linear regression between co-variates other than Anest ESP/Sham ESP.

The statistical software package Jamovi version 2.3.28.0 (The Jamovi Project, n.d.) was used to conduct the statistical analysis. Categorical data are expressed as numbers and percentages, whereas continuous variables are expressed as mean ± standard deviation (SD) or median with interquartile range (IQR). The independent t-test or Mann-Whitney U test for continuous variables and the Chi-squared test or Fisher exact test for categorical variables, respectively, were used to assess differences between groups. Statistical significance was defined as P<0.05.

Results

Between January 2023 and January 2024, a total of 50 patients were enrolled in the study, with three subsequently excluded due to protocol deviations. One patient withdrew consent, while two received fentanyl instead of remifentanil during induction of general anesthesia, contrary to the trial protocol (Figure 1). We performed a total of 22 major resections (19 lobectomies and three segmentectomies). In all cases indication was malignant disease, therefore lymphadenectomy was always performed. As minor surgeries, we enrolled seven wedge resections, five bullectomies and three lung volume reductions.

Figure 1 Flow of patient randomization and categorization into treatment groups. ESP, erector spinae plane; TEA, thoracic epidural analgesia.

Patients were randomly assigned to two groups:

• Sham ESP group: received an ESP block with saline and a TPV block with local anesthetic (ropivacaine 0.375%);
• Anest ESP group: received an ESP block with local anesthetic (ropivacaine 0.375%) and a TPV block with saline.

A total of 47 patients were analyzed: 23 in the Sham ESP group and 24 in the Anest ESP group (see Table 1 for patient characteristics).

In the Sham ESP group, 8 (34,7%) patients required the placement of a peridural catheter. Of these, three were excluded from the study after conversion to thoracotomy, while the remaining five had ineffective blocks requiring the escape strategy, which in our study was defined as peridural catheter.

In the Anest ESP group, 12 (50%) patients needed a peridural catheter. Of these, four were excluded after conversion to thoracotomy, and the other eight required the escape strategy, which in our study was defined as peridural catheter.

There was no statistically significant difference between the Anest ESP and Sham ESP groups in the need for an escape strategy due to block ineffectiveness (P=0.31). All conversions to thoracotomy occurred during anatomical resections.

Linear regression analyses did not show any statistical significant impact of co-variates (age, gender, body mass index, use of NSAIDs, duration of surgery, oncological, cardiovascular, and pulmonary comorbidities) and primary outcomes (dose of rescue opioids at 24 and 48 hours).

Linear regression analyses did not show any statistical significant impact of co-variates (age, gender, body mass index, use of NSAIDs, duration of surgery, oncological, cardiovascular and pulmonary comorbidities) and primary outcomes. Opioids consumption at 24 hours: adjusted R²=0.11; F(9, 16) =1.5; P=0.28. Opioids consumption at 48 hours: adjusted R²=0.12; F(9, 16) =1.41; P=0.26. Details are displayed in Table 2.

We conducted a one-sided equivalence test to assess the non-inferiority of ESP block (Anest ESP) compared to TPV block (Sham ESP) in morphine consumption at 24 hours, yielding non-statistically significant results (P=0.69) (Figure 2). Analysis of morphine usage in the first 48 hours revealed no statistically significant differences between groups (P=0.09 at 24 hours; P=0.12 at 48 hours) (Anest ESP 24 hours 17.9 mg, Sham ESP 24 hours 10.7 mg; Anest ESP 48 hours 19.8 mg; Sham ESP 48 hours 12.6 mg). Evaluation of pain using the NRS scale showed no significant difference at 4 hours at rest (P=0.08), neither after coughing (P=0.15). Secondary outcomes included low rates of nausea (one patient in the Anest ESP group, 8.33%), no vomiting occurred in the first 48 hours postoperatively, and urinary retention in four cases (three randomized in the Sham ESP group, 18.75%, and one in the Anest ESP group 8.33%). Block execution was uncomplicated, with mean durations of 3 (SD, 1.84) minutes for ESP and 3.74 (SD, 2.23) minutes for TPV.

Figure 2 One-sided equivalence test.

Cardiopulmonary complication occurred in one patient who had postoperative atrial fibrillation after lobectomy. Considering the low rate of complications, no further analysis was conducted. The median LOS was 2.3 days in the Sham ESP group and 2.5 days in the Anest ESP group, resulting in a non-significant difference (P=0.81).

A sub-analysis based on the type of surgery was performed. Where major surgery are the anatomical resections and minor surgery are the extra-anatomical resections, we can say that 22 (46%) patients underwent anatomical resections and 25 (54%) underwent extra-anatomical resections. Among those undergoing VATS anatomical resections, 11 were randomized to the Sham ESP group and 11 to the Anest ESP group.

As postulated, patients undergoing major surgery reported significant greater pain compared to those who had minor surgeries [median NRS scale after coughing 8 (IQR, 2.5) vs. 5 (IQR, 4), P=0.045, instead at rest 6 (IQR, 4) vs. 3 (IQR, 4), P=0.049]. Nevertheless, this was not sufficient to require more peridural in the first group. Indeed, of the 11 patients undergoing major surgery in the Sham ESP group, six had ineffective blockade requiring peridural catheter placement, with three requiring catheters due to conversion to thoracotomy. In the non-anatomical resection group, 12 and 13 patients were randomized to the Sham ESP and Anest ESP groups, respectively, with two and four requiring peridural catheters in each group. There was no statistically significant difference between major surgery and minor surgery groups in the need for an escape strategy due to block ineffectiveness (P=0.14).

Discussion

In this prospective, randomized, multiple-blinded study, we aimed to evaluate the effectiveness, in a perspective of non-inferiority, of the ESP block compared to the paravertebral TPV block in video-assisted thoracoscopic surgery, starting from the known efficacy of the TPV block in VATS (1). Altogether, our study did not formally demonstrate non-inferiority of the ESP block compared to the TPV block. However, looking at each evaluated outcome, we did not find statistically significant difference between the two procedures. For the main outcome (cumulative dose of opioids consumed via patient-controlled intravenous morphine) there was no relevant difference.

Although VATS is less invasive than thoracotomy, it can still result in interfering pain, leading to complications such as respiratory distress and chronic pain (2-4). Thus, optimizing post-operative pain management is essential.

Traditionally, TEA has been used for pain management and it has been historically used in our experience, but it can be invasive and challenging to perform (5). Our study aimed to explore less invasive alternatives, such as the TPV and ESP blocks, which are easier to perform. In our study, both ESP and TPV were performed without any complication with a mean execution time of few minutes. TEA has been used as escape strategy in case of ineffective blocks due to the consolidated experience with this procedure, and to the conversion from a single shot technique to a patient-controlled analgesia. Standardizing analgesic approaches may contribute to improved pain management outcomes. Despite numerous studies, there is no consensus on the gold standard for pain management, aside from TEA, which carries inherent risks (5), therefore, finding a valid and safe alternative is desirable. Our results suggest that a regional analgesia with single shots might be a viable strategy with few considerations. We could speculate about different techniques for different type of surgery. Based on conversions to open thoracotomy that all append during anatomical lung resections, and on the fact that these patients, even operated on with VATS, experienced more intense pain compared to those who had minor procedures, we might suggest to start using single blocks for non-anatomical resections. This might also be supported by the different mean time of pleural drain stay (1.3 days in minor procedures vs. 2.3 days in major procedures), meaning that a more complex surgery requiring longer drain stay and hospital stay might need different pain management.

Regarding the best technique, unfortunately, we cannot make any definitive conclusions. Indeed, our study did not clearly state the non-inferiority of ESP over TPV, but we did not find major differences when comparing single outcomes. For example, the rate of TEA placed for block failure was equal in both groups. The no statistically significant difference in the first 24 hours of several outcomes considered in our study confirms what was stated in the meta-analysis by Capuano et al. (33).

A reasonable and cautious approach for those units that want to gradually explore differentiated strategy for pain management after thoracic surgery, would be to introduce single shots analgesia for minor procedures performed with minimally invasive access. The shorter surgical trauma on chest wall and intercostal nerves, along with a possible shorter drain stay, could make this group of patients the best candidates to start with. With enough confidence and skills, and with a good selection of patients, blocks might be extended also to major surgeries, along with other pain management modalities. In our study there was a statistically significant difference in pain severity experienced by patients who had minor vs. major surgeries, however the discrepancy was not marked and not so relevant to require different escape strategies (TEA). We believe that, single shot regional analgesia could be widely used in different types of resections with good outcomes. The best strategy needs to be addressed and it could also rely on preferences and expertise. Once the technique is perfected, further analysis should be performed to better select patients and procedures to minimize the risk of escape strategies and broaden indications.

Certainly, our study has several limitations. Firstly, locoregional anesthesia was performed after general anesthesia, preventing evaluation of block efficacy preoperatively and potentially leading to treatment failures requiring rescue therapy, such as thoracic epidurals. Furthermore, our study raises concerns regarding the mechanism of action of the ESP block. Performing both blocks with different solutions supports the possibility of compartmental communication and dilution of the anesthetic by the saline solution, suggesting the need for further investigation. Having had only one cardiopulmonary complication in the whole series, we could not make any relevant analysis on the effect of ESP and TPV on complications, which is the best indicator of effective pain management in real world.

Conclusions

In conclusion, our study contributes to the ongoing discussion on pain management strategies in VATS, highlighting the potential of both ESP and TPV blocks as alternatives to traditional approaches like TEA. However, the study’s limitations, including the timing of locoregional anesthesia administration and concerns about block efficacy and mechanism of action, underscore the need for further research in this area. Future studies should focus on optimizing patients’ selection, standardizing analgesic protocols, and elucidating the underlying mechanisms of locoregional anesthesia techniques to enhance post-operative pain management and patient outcomes.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the CONSORT reporting checklist. Available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-1548/rc

Trial Protocol: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-1548/tp

Data Sharing Statement: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-1548/dss

Peer Review File: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-1548/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-1548/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). The study, under risk category A, according to ClinO, Art. 61 (clinical trial with intervention with minimal risks and burdens, investigating neither therapeutic products, nor devices, nor transplant products), was approved by the ethics committee of Ticino (No. 022-01759, Rif CETI 4206) and was registered on https://clinicaltrials.gov with the ID NCT05798585. Informed consent was taken from all the patients.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Steinthorsdottir KJ, Wildgaard L, Hansen HJ, et al. Regional analgesia for video-assisted thoracic surgery: a systematic review. Eur J Cardiothorac Surg 2014;45:959-66. [Crossref] [PubMed]
2. Falcoz PE, Puyraveau M, Thomas PA, et al. Video-assisted thoracoscopic surgery versus open lobectomy for primary non-small-cell lung cancer: a propensity-matched analysis of outcome from the European Society of Thoracic Surgeon database. Eur J Cardiothorac Surg 2016;49:602-9. [Crossref] [PubMed]
3. Bendixen M, Jørgensen OD, Kronborg C, et al. Postoperative pain and quality of life after lobectomy via video-assisted thoracoscopic surgery or anterolateral thoracotomy for early stage lung cancer: a randomised controlled trial. Lancet Oncol 2016;17:836-44. [Crossref] [PubMed]
4. McKenna RJ Jr, Houck W, Fuller CB. Video-assisted thoracic surgery lobectomy: experience with 1,100 cases. Ann Thorac Surg 2006;81:421-5; discussion 425-6. [Crossref] [PubMed]
5. Ljungqvist O, Scott M, Fearon KC. Enhanced Recovery After Surgery: A Review. JAMA Surg 2017;152:292-8. [Crossref] [PubMed]
6. Kehlet H, Wilmore DW. Evidence-based surgical care and the evolution of fast-track surgery. Ann Surg 2008;248:189-98. [Crossref] [PubMed]
7. Batchelor TJP, Rasburn NJ, Abdelnour-Berchtold E, et al. Guidelines for enhanced recovery after lung surgery: recommendations of the Enhanced Recovery After Surgery (ERAS®) Society and the European Society of Thoracic Surgeons (ESTS). Eur J Cardiothorac Surg 2019;55:91-115. [Crossref] [PubMed]
8. Haager B, Schmid D, Eschbach J, et al. Regional versus systemic analgesia in video-assisted thoracoscopic lobectomy: a retrospective analysis. BMC Anesthesiol 2019;19:183. [Crossref] [PubMed]
9. De Cosmo G, Aceto P, Gualtieri E, et al. Analgesia in thoracic surgery Minerva Anestesiol 2009;75:393-400. review. [PubMed]
10. Mungroop TH, Veelo DP, Busch OR, et al. Continuous wound infiltration versus epidural analgesia after hepato-pancreato-biliary surgery (POP-UP): a randomised controlled, open-label, non-inferiority trial. Lancet Gastroenterol Hepatol 2016;1:105-13. [Crossref] [PubMed]
11. Joshi GP, Bonnet F, Shah R, et al. A systematic review of randomized trials evaluating regional techniques for postthoracotomy analgesia. Anesth Analg 2008;107:1026-40. [Crossref] [PubMed]
12. Messina M, Boroli F, Landoni G, et al. A comparison of epidural vs. paravertebral blockade in thoracic surgery. Minerva Anestesiol 2009;75:616-21. [PubMed]
13. Thavaneswaran P, Rudkin GE, Cooter RD, et al. Brief reports: paravertebral block for anesthesia: a systematic review. Anesth Analg 2010;110:1740-4. [Crossref] [PubMed]
14. Marret E, Bazelly B, Taylor G, et al. Paravertebral block with ropivacaine 0.5% versus systemic analgesia for pain relief after thoracotomy. Ann Thorac Surg 2005;79:2109-13. [Crossref] [PubMed]
15. Karmakar MK. Thoracic paravertebral block. Anesthesiology 2001;95:771-80. [Crossref] [PubMed]
16. Davies RG, Myles PS, Graham JM. A comparison of the analgesic efficacy and side-effects of paravertebral vs epidural blockade for thoracotomy--a systematic review and meta-analysis of randomized trials. Br J Anaesth 2006;96:418-26. Erratum in: Br J Anaesth 2007;99:768. [Crossref] [PubMed]
17. Powell ES, Cook D, Pearce AC, et al. A prospective, multicentre, observational cohort study of analgesia and outcome after pneumonectomy. Br J Anaesth 2011;106:364-70. [Crossref] [PubMed]
18. Piccioni F, Ragazzi R. Anesthesia and analgesia: how does the role of anesthetists changes in the ERAS program for VATS lobectomy. J Vis Surg 2018;4:9. [Crossref] [PubMed]
19. Chen N, Qiao Q, Chen R, et al. The effect of ultrasound-guided intercostal nerve block, single-injection erector spinae plane block and multiple-injection paravertebral block on postoperative analgesia in thoracoscopic surgery: A randomized, double-blinded, clinical trial. J Clin Anesth 2020;59:106-11. [Crossref] [PubMed]
20. Gürkan Y, Aksu C, Kuş A, et al. Erector spinae plane block and thoracic paravertebral block for breast surgery compared to IV-morphine: A randomized controlled trial. J Clin Anesth 2020;59:84-8. [Crossref] [PubMed]
21. Kietaibl S, Ferrandis R, Godier A, et al. Regional anaesthesia in patients on antithrombotic drugs: Joint ESAIC/ESRA guidelines. Eur J Anaesthesiol 2022;39:100-32. [Crossref] [PubMed]
22. Semyonov M, Fedorina E, Grinshpun J, et al. Ultrasound-guided serratus anterior plane block for analgesia after thoracic surgery. J Pain Res 2019;12:953-60. [Crossref] [PubMed]
23. Wilson JM, Lohser J, Klaibert B. Erector Spinae Plane Block for Postoperative Rescue Analgesia in Thoracoscopic Surgery. J Cardiothorac Vasc Anesth 2018;32:e5-e7. [Crossref] [PubMed]
24. Finnerty DT, McMahon A, McNamara JR, et al. Comparing erector spinae plane block with serratus anterior plane block for minimally invasive thoracic surgery: a randomised clinical trial. Br J Anaesth 2020;125:802-10. [Crossref] [PubMed]
25. Forero M, Adhikary SD, Lopez H, et al. The Erector Spinae Plane Block: A Novel Analgesic Technique in Thoracic Neuropathic Pain. Reg Anesth Pain Med 2016;41:621-7. [Crossref] [PubMed]
26. El-Boghdadly K, Pawa A. The erector spinae plane block: plane and simple. Anaesthesia 2017;72:434-8. [Crossref] [PubMed]
27. Bang S. Erector spinae plane block: an innovation or a delusion? Korean J Anesthesiol 2019;72:1-3. [Crossref] [PubMed]
28. Fernandez FG, Falcoz PE, Kozower BD, et al. The Society of Thoracic Surgeons and the European Society of Thoracic Surgeons general thoracic surgery databases: joint standardization of variable definitions and terminology. Ann Thorac Surg 2015;99:368-76. [Crossref] [PubMed]
29. Hamilton DL. Reducing the risk of pneumothorax following erector spinae plane block. J Clin Anesth 2019;56:3. [Crossref] [PubMed]
30. Aksu C, Gürkan Y. Erector spinae plane block: A new indication with a new approach and a recommendation to reduce the risk of pneumothorax. J Clin Anesth 2019;54:130-1. [Crossref] [PubMed]
31. Zhao H, Xin L, Feng Y. The effect of preoperative erector spinae plane vs. paravertebral blocks on patient-controlled oxycodone consumption after video-assisted thoracic surgery: A prospective randomized, blinded, non-inferiority study. J Clin Anesth 2020;62:109737. [Crossref] [PubMed]
32. Sealed Envelope Ltd. Power calculator for continuous outcome non-inferiority trial. 2012. Accessed Feb 26, 2024. Available online: https://www.sealedenvelope.com/power/continuous-noninferior/
33. Capuano P, Hileman BA, Martucci G, et al. Erector spinae plane block versus paravertebral block for postoperative pain management in thoracic surgery: a systematic review and meta-analysis. Minerva Anestesiol 2023;89:1042-50. [Crossref] [PubMed]