Yumin Jo and Seyeon Park are contributed equally to this work as first co-authors.
Various regional analgesia techniques are used to reduce postoperative pain in patients undergoing video-assisted thoracic surgery (VATS). This study aimed to determine the relative efficacy of regional analgesic interventions for VATS using a network meta-analysis.
We searched the Medline, EMBASE, Cochrane Controlled Trial Register, Web of Science, and Google Scholar databases to identify all randomized controlled trials (RCTs) that compared the analgesic effects of the following interventions: control, thoracic paravertebral block (TPVB), erector spinae plane block (ESPB), serratus plane block (SPB), and intercostal nerve block (INB). The primary outcome was opioid consumption during the first 24 h postoperative period. Pain scores were also collected during three different postoperative periods: the early (0–6 h), middle (6–18 h), and late (18–24 h) periods.
A total of 21 RCTs (1,391 patients) were included. TPVB showed the greatest effect on opioid consumption compared with the control (mean difference [MD]: −13.2 mg, 95% CI [−16.2, −10.1]). In terms of pain scores in the early period, ESPB had the greatest effect compared to control (MD: −1.6, 95% CI [−2.3, −0.9]). In the middle and late periods, pain scores showed that TPVB, ESPB and INB had superior analgesic effects compared to controls, while SPB did not.
TPVB had the best analgesic efficacy following VATS, though the analgesic efficacy of ESPBs was comparable. However, further studies are needed to determine the optimal regional analgesia technique to improve postoperative pain control following VATS.
The use of video-assisted thoracic surgery (VATS), a minimally invasive alternative to open thoracotomy, has increased over the years, which has led to a significant reduction in postoperative pain and shorter hospital stays [
Thoracic paravertebral block (TPVB) provides unilateral thoracic analgesia comparable to TEA. Additionally, not only is it less invasive than TEA, but can also maintain hemodynamic stability and carries lower risk of complications due to anticoagulation therapy associated with anticoagulation [
Recently, however, various regional analgesia techniques, such as the erector spinae plane block (ESPB) and the serratus plane block (SPB), have superseded the traditional TPVB through their comparable analgesic effect along with reduced associated complications [
Therefore, we identified and reviewed all the articles that investigated the effects of various techniques used for postoperative analgesia for VATS, and performed an NMA to the rank order of the regional analgesia in terms of effectiveness for VATS. Our primary outcome was opioid consumption during the first 24 h postoperative period, and we also evaluated pain severity during three different postoperative periods (the early, middle, and late periods).
This study was conducted in accordance with the recommended Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines [
The literature search was conducted to identify eligible studies for this systematic review and meta-analysis. Two researchers (S.P. and B.H.) independently searched the following electronic databases: Medline, EMBASE, Cochrane Controlled Trial Register, Web of Science, and Google Scholar for relevant studies published in English. Articles published between September 2005 and December 2020 in peer-reviewed journals were included. The primary search was conducted on January 28, 2021; however, an additional search was conducted on February 28, 2021 to include more recent studies. In addition, the studies referenced in the selected articles were searched manually.
The search strategy was as follows: (“Video assisted thoracoscopy surgery” or VATS) and [(“Thoracic paravertebral block” or TPVB) or (“paravertebral block” or PVB) or (“Serratus plane block” or “Serratus anterior plane block” or “Serratus interfascial plane block” or SPB) or (“Erector spinae plane block” or ESPB) or (“Intercostal nerve block” or INB)].
Studies were considered eligible if they were randomized controlled trials (RCTs) published in English that reported postoperative pain scores or total postoperative opioid consumption in both the experimental and control groups as outcomes. Non-RCTs (quasi-experimental designs), abstracts, conference proceedings, unpublished gray literature, and review studies were excluded. Among the regional analgesia techniques, continuous blocks via catheterization were also excluded.
We performed six steps to select the studies. First, two researchers (S.P. and B.H.) imported the titles and abstracts of the articles identified in the searches into reference management software (EndNote 20, ClarivateTM) and performed a preliminary review. Second, duplicate papers were identified and eliminated using the reference management software. Third, two researchers (S.P. and B.H.) independently reviewed the imported studies. We excluded all of the imported studies that did not clearly meet the inclusion criteria (due to the study design, participants, types of intervention, and comparison groups). Fourth, they also independently screened the titles, abstracts, and methodology sections of the studies that appeared to meet the inclusion criteria. Fifth, we retrieved the full texts of the papers that met all the inclusion criteria for data extraction and linked multiple reports of the same study. Finally, the studies included in the final selection were confirmed and coded for analysis by two researchers (B.H. and Y.J.). These coding sheets were independently checked for accuracy by researchers who were not involved in the review process. If there were any differences between the codes provided by the two reviewers, the discrepancies were resolved by consulting a third independent reviewer (C.O.).
The information from the included articles was independently extracted by two reviewers (B.H. and Y.J.), and each selected article was reviewed twice by both reviewers. To determine the outcomes of individual studies, pain scores and opioid consumption were determined for each group and recorded as the means and standard deviations (SDs). Medians and interquartile ranges (IQRs), as approximations of the mean and SDs, were determined using the estimation method proposed by Wan et al. [
The primary outcome was cumulative opioid consumption during the first 24 h postoperative period. All opioids were converted to equianalgesic intravenous (IV) morphine doses (IV morphine 1 mg = IV fentanyl 10 µg = IV sufentanil 2 µg = IV tramadol 10 mg). The secondary outcome was pain scores assessed during three different periods in the first 24 h, namely, the early (0–6 h), middle (6–18 h), and late (18–24 h) periods. For studies that included several time points within each time period, pain scores close to 1 h for early, close to 12 h for middle, and close to 24 h for late were used. In the one study that timetable was expressed as an interval (ex. 6 a.m. to 2 p.m.), a similar period expected to include the interval was used. Pain scores that were assessed using visual analogue scales (VAS) were converted to a 0–10 analogue scale to allow for statistical evaluation.
A random-effects NMA within a frequentist framework was performed using the R software version 4.0.3 (R Foundation for Statistical Computing, Austria) and the “netmeta” package for frequentist NMA [
The literature screening process and results are shown in
Individual studies were assessed using the Cochrane Collaboration’s Risk of Bias tool [
The results of the I2 and Q statistics (based on the full design-by-treatment interaction random-effects model) indicated that a random-effects model may be suitable for revealing any inconsistency or heterogeneity in our network model (
Of the included studies, 17 [
During proofreading, we noticed that the article which included our analysis had been retracted from its journal [
Various regional analgesia techniques are used in clinical settings to improve postoperative pain management in VATS, and our NMA not only demonstrated the potential benefits of these but also ranked them based on efficacy. When compared with mere systemic analgesia, all four regional analgesic techniques significantly reduced cumulative opioid consumption during the first 24 h postoperative period. In particular, TPVB showed remarkable effectiveness in reducing opioid consumption. Additionally, ESPB ranked highest for lowering the pain score in the early postoperative period, while the effect size of TPVB was clinically similar to that of ESPBs. In the case of SPB, however, even though the statistical significance of opioid consumption was clear, the effect size was approximately half that of the other methods. Moreover, the pain scores measured in the middle and late periods were not significantly different compared to control.
Statistically significant differences are not always clinically significant— e.g., a difference of 10 mg or more in parenteral morphine [
TPVB showed a reduction of 13.2 mg in opioid consumption along with a reduction of more than 1 point in the pain score, which were viewed as clinically significant. For ESPB, the reduction in opioid consumption was 8.71 mg, which was less than 10 mg, but the decrease in the pain score was 1.6, showing the best results in the early postoperative period. However, this result had direct and indirect inconsistencies; therefore, caution should be taken when interpreting these results. Two studies, which were performed by Ciftci et al. [
ESPB is an emerging technique that has been widely applied in multiple fields. Importantly, it can be easily administered even by trainees [
According to a recent Cochrane review, while TPVB was as effective as TEA for controlling acute pain, TPVB was associated with fewer complications, such as hypotension, urinary retention, nausea, and vomiting [
INB is a well-known traditional technique for pain management after thoracic surgery. INB can be performed easily using various techniques, such as ultrasonography or blind techniques. In addition, a thoracic surgeon can directly inject inside the thorax [
SPB can be easily performed in the lateral decubitus position, which is the surgical position for thoracic surgery [
This study has several limitations. First, the included studies were highly heterogeneous. Although the present study included only RCTs in patients who underwent VATS, the concentrations of drugs and technical details were not consistent. In addition, various drugs were used for multimodal analgesia. Second, the time points at which pain scores were measured were not consistent between studies and were not always presented as accurate values. To reduce any bias, we divided the time period into three intervals and used the values corresponding to each interval as representative values. Third, the sample size was insufficient to draw definitive conclusions. Lastly, ESPB and SPB are currently developing techniques, which may lead to possible publication bias. In conclusion, in this study, NMA was conducted to compare regional analgesia techniques in terms of their efficacy at improving postoperative pain control after VATS. TPVB showed outstanding analgesic effects and ESPB led to the greatest reduction in pain scores during the early postoperative period. However, given the significant reduction in opioid consumption seen with all the four regional analgesic techniques evaluated, using any of these regional blocks after VATS seems reasonable. Further and more refined studies are needed to determine the optimal regional analgesia technique to improve postoperative pain control after VATS.
This work was supported by research funding from the National Research Foundation of Korea (NRF-2019R1G1A1099660).
No potential conflict of interest relevant to this article was reported.
Yumin Jo (Writing – original draft; Writing – review & editing)
Seyeon Park (Data curation; Formal analysis; Methodology; Visualization)
Chahyun Oh (Investigation; Software; Validation)
Yujin Pak (Methodology; Project administration; Resources)
Kuhee Jeong (Visualization; Writing – review & editing)
Sangwon Yun (Visualization; Writing – review & editing)
Chan Noh (Formal analysis; Resources; Validation)
Woosuk Chung (Conceptualization; Writing – review & editing)
Yoon-Hee Kim (Resources; Supervision; Writing – review & editing)
Young Kwon Ko (Conceptualization; Supervision; Writing – review & editing)
Boohwi Hong (Conceptualization; Data curation; Supervision; Writing – original draft; Writing – review & editing)
24 hours opioid consumption.
Pain score at postoperative early (up to 6 hours) period.
Pain score at postoperative middle (6 to 18 hours) period.
Pain score at postoperative late (18 to 24 hours) period.
Confidence rating of each outcomes.
24 hours opioid consumption after removal of retracted article.
Study flow diagram.
Assessment of risk of bias of included studies. The overall quality of the included studies were deemed satisfactory.
Network plots and forest plots for the network meta-analysis. (A) opioid consumption in the first 24 h post-operation, (B) early postoperative period (up to 6 h) pain scores, (C) middle postoperative period (6–18 h) pain scores, and (D) late postoperative period (18–24 h) pain scores. The mean difference (MD) and 95% CI are shown. ESPB: erector spinae plane block, INB: intercostal nerve block, SPB: serratus plane block, TPVB: thoracic paravertebral block.
Characteristics of the Included Studies
Author & Year | Country | Surgery | Port | Group(s) (n) | Block level | Localization | Local anesthetics | Block timing | Opioid data | Pain score data representation method (early, middle, late period [h]) |
---|---|---|---|---|---|---|---|---|---|---|
Liu, 2021 [ |
China | Lobectomy, wedge resection, segmentectomy | 1 | ESPB (40); control (40) | T5 | Ultrasound | 25 ml of 0.4% ropivacaine | Before induction | Sufentanil | Table (2, 8, 24) |
Hu, 2021 [ |
China | Wedge resection | 1 | TPVB (30); control (30) | T4, intrathoracic approach | Thoracoscopic-assisted | 20 ml of 0.375% ropivacaine | End of surgery | Sufentanil | Table (6, 12, 24) |
Zhao, 2020 [ |
China | Lobectomy, wedge resection, segmentectomy | NA | ESPB (33); TPVB (33) | ESPB: T4 and T6 | Ultrasound | 30 ml of 0.4% ropivacaine | Before induction | Oxycodone | Table (NA, NA, 24) |
Yao, 2020 [ |
China | Lobectomy, segmentectomy | NA | ESPB (37); control (38) | T5 | Ultrasound | 25 ml of 0.5% ropivacaine | Before induction | Sufentanil | Table (1, 8, 24) |
Viti, 2020 [ |
Italy | Lobectomy, segmentectomy | 3 | SPB (46); control (44) | Fifth rib | Ultrasound | 30 ml of 0.3% ropivacaine | After induction | No data | Plot (NA, 6 a.m. to 2 p.m. POD 1, 2 p.m. to 10 p.m. POD 1) |
Turhan, 2020 [ |
Turkey | Lobectomy, segmentectomy | 2 | ESPB (35); TPVB (35); INB (36) | ESPB, TPVB: fifth rib | ESPB, TPVB: ultrasound | 20 ml of 0.5% ropivacaine | TPVB, ESPB: before induction | Morphine mg equivalent | Table (1, 12, 24) |
INB: T4–T7 | INB: thoracoscopic-assisted | INB: after induction | ||||||||
Lee, 2020 [ |
Korea | Lobectomy | 3 | INB (23); SPB (23) | Fifth rib | INB: thoracoscopic-assisted | 20 ml of 0.375% ropivacaine | INB: end of the surgery | Fentanyl | Table (2, 12, 24) |
SPB: ultrasound | SPB: after induction | |||||||||
Kim, 2020 [ |
Korea | Wedge resection for primary spontaneous pneumothorax | 1 | INB (25); SPB (25) | Fifth rib | INB: thoracoscopic-assisted | 20 mL of | INB: end of the surgery | Fentanyl, | Table (3, 12, NA) |
SPB: ultrasound | 0.375% ropivacaine | SPB: after induction | no standard time (chest tube removal) | |||||||
Finnerty, 2020 [ |
Ireland | Wedge resection, pleurodesis, pleurectomy, lobectomy, decortication, bullectomy, or pleural biopsy | NA | ESPB (30); SPB (30) | T5, fifth rib | Ultrasound | 30 ml of 0.25% levobupivacaine | After induction | Oxycodone | Plot (1, 12, 24) |
Ciftci, 2020 [ |
Turkey | Lobectomy, wedge resection | 3 | ESPB (30); TPVB (30); control (30) | T5 | Ultrasound | 20 ml of 0.25% bupivacaine | Before induction | Fentanyl, 48 h of data only | Plot (1, 8, 24) |
Ciftci, 2020 [ |
Turkey | Lobectomy | NA | ESPB (30); control (30) | T5 | Ultrasound | 20 ml of 0.25% bupivacaine | Before induction | Fentanyl | Table (2, 8, 24) |
Chu, 2020 [ |
China | Lobectomy, wedge resection, segmentectomy | NA | TPVB (25); control (24) | T4, T7 | Ultrasound | 20 ml of 0.375% ropivacaine | Unknown | Sufentanil, no data | Table (1, NA, 24) |
Cheng, 2020 [ |
China | Lobectomy | 1 | SPB (25) (modified intercostal nerve block); control (25) | Fourth and fifth rib | Ultrasound | 10 ml of 0.35% ropivacaine | After induction | Sufentanil | NA |
Chen, 2020 [ |
China | Lobectomy, wedge resection, segmentectomy | 2 | TPVB (24); INB (24); ESPB (24) | TPVB: T5, T6, T7 | Ultrasound | 20 ml of 0.375% ropivacaine | After induction | Morphine mg equivalent | Plot (2, 8, 24) |
INB: T4–T9 | ||||||||||
ESPB: T5 | ||||||||||
Gaballah, 2019 [ |
Egypt | Wedge resection, decortication, bullectomy, pleural biopsy, pleurodesis, repair of bronchopleural fistula, diaphragmatic plication | NA | ESPB (30); SPB (30) | ESP: T5 | Ultrasound | 20 ml of 0.25% bupivacaine | After induction | Pethidine | Plot (1, 12, 24) |
SPB: T7 | ||||||||||
Wu, 2018 [ |
China | Wedge resection, lobectomy, bilobectomy, pneumonectomy | NA | TPVB (34); INB (32) | TPVB: T5 | Ultrasound | 0.3 ml/kg of 0.5% ropivacaine | Before induction | Sufentanil | Plot (1, 10, 24) |
INB: fourth and seventh intercostal space | ||||||||||
Okmen, 2018 [ |
Turkey | Wedge resection, lobectomy | NA | SPB (20); control (20) | Fifth rib | Ultrasound | 20 ml of 0.25% bupivacaine | End of surgery | Tramadol | Table (2, 12, 24) |
Kim, 2018 [ |
Korea | Lobectomy, wedge resection, segmentectomy | 2 or 3 | SPB (42); control (43) | Fifth rib | Ultrasound | 0.4 ml/kg of 0.375% ropivacaine | After induction | Morphine mg equivalent | Plot (NA, 12, 24) |
Ahmed, 2017 [ |
Pakistan | Elective diagnostic VATS | NA | INB (30); control (30) | 5 level | Bone landmark | 20 ml of 0.25% bupivacaine | End of surgery | Morphine | Plot (1, 12, 24) |
Kaya, 2006 [ |
Turkey | Wedge resection, lung biopsy, pleural biopsy | NA | TPVB (25); control (22) | T4–T8, 5 level | Bone landmark | 20 ml of 0.5% bupivacaine | Before induction | Morphine | Table (1, 8, 24) |
Vogt, 2005 [ |
Switzerland | Biopsy, lung resection, pleurodeses, resection of intrathoracic tumor | NA | TPVB; control | T6 | Bone landmark | 0.4 ml/kg of 0.375% bupivacaine | After induction | Morphine | Plot (1, NA, 24) |
ESPB: erector spinae plane block, INB: intercostal nerve block, SPB: serratus plane block, TPVB: thoracic paravertebral block, NA: not applicable.
Results of Model, Heterogeneity, Consistency Test, and GRADE Quality of Evidence Assessment for the Primary and Secondary Outcomes
Outcomes | No. of studies | No. of patients | No. of pairwise comparisons | No. of designs | I2 (%) | Consistency test |
Quality of the evidence (GRADE) | Comments | |
---|---|---|---|---|---|---|---|---|---|
Global P value | Local P value | ||||||||
Opioid consumption | 17 | 1073 | 21 | 9 | 86.9 | 0.833 | All comparisons were insignificant | ⊕⊕ | Downgraded for concerns related to inconsistency and publication bias |
Low quality | |||||||||
Early postoperative period (up to 6 h) pain scores | 18 | 1146 | 24 | 9 | 92.1 | 0.353 | ESPB vs. control significant (P = 0.014), other comparisons insignificant | ⊕⊕ | Downgraded for concerns related to inconsistency and publication bias |
Low quality | |||||||||
Middle postoperative period (6 to 18 h) pain scores | 16 | 1062 | 22 | 9 | 92.6 | 0.159 | ESPB vs. control significant (P = 0.004), other comparisons insignificant | ⊕⊕ | Downgraded for concerns related to inconsistency and publication bias |
Low quality | |||||||||
Late postoperative period (18 to 24 h) pain scores | 17 | 1250 | 23 | 9 | 81.8 | 0.935 | All comparisons were insignificant | ⊕ | Downgraded for concerns related to imprecision, inconsistency, and publication bias |
Very low quality |
I2: Higgins’ I2, global inconsistency based on the full design-by-treatment interaction random-effects model [
Network League Table for All the Interventions in Regard to Opioid Consumption and Pain Scores at the Early (up to 6 h), Middle (6–18 h), and Late (18–24 h) Post-operative Periods
Opioid consumption | ||||
Control | 8.59 (5.22, 11.96) | 7.00 (−2.24, 16.24) | 7.09 (2.94, 11.24) | 12.64 (8.30, 16.98) |
8.71 (6.06, 11.35) | ESPB | 2.75 (−1.78, 7.28) | −6.47 (12.95, 0.02) | 5.08 (1.42, 8.74) |
9.55 (5.89, 13.21) | 0.85 (−2.63, 4.32) | INB | −1.50 (11.94, 8.94) | 3.69 (0.15, 7.23) |
5.92 (2.48, 9.35) | −2.79 (−6.57, 1.00) | −3.63 (−8.14, 0.88) | SPB | - |
13.17 (0.12, 16.21) | 4.46 (1.53, 7.39) | 3.62 (0.43, 6.80) | 7.25 (3.03, 11.47) | TPVB |
Early postoperative period (up to 6 h) pain scores | ||||
Control | 2.25 (1.37, 3.14) | 1.10 (-0.63, 2.83) | 0.85 (-0.44, 2.14) | 1.25 (0.41, 2.09) |
1.59 (0.88, 2.29) | ESPB | 0.43 (-0.98, 1.84) | -0.20 (-1.60, 1.20) | 0.43 (-0.70, 1.56) |
1.36 (0.50, 2.23) | -0.22 (-1.13, 0.69) | INB | -0.40 (-1.79, 0.98) | 0.37 (-0.71, 1.46) |
1.05 (0.17, 1.94) | -0.53 (-1.45, 0.38) | -0.31 (-1.27, 0.65) | SPB | - |
1.47 (0.76, 2.17) | -0.12 (-0.94, 0.71) | 0.11 (-0.76, 0.97) | 0.42 (-0.59, 1.43) | TPVB |
Middle postoperative period (6–18 h) pain scores | ||||
Control | 1.98 (1.15, 2.81) | 0.40 (-1.23, 2.03) | 0.04 (-1.26, 1.34) | 1.25 (0.27, 2.23) |
1.28 (0.59, 1.97) | ESPB | 0.62 (-0.86, 2.09) | 0.06 (-1.25, 1.37) | 0.49 (-0.60, 1.58) |
0.93 (0.09, 1.78) | -0.35 (-1.23, 0.54) | INB | 0.04 (-1.22, 1.31) | 0.32 (-0.70, 1.34) |
0.78 (-0.07, 1.64) | -0.50 (-1.37, 0.38) | -0.15 (-1.06, 0.76) | SPB | - |
1.30 (0.53, 2.07) | 0.02 (-0.81, 0.85) | 0.37 (-0.47, 1.20) | 0.52 (-0.48, 1.52) | TPVB |
Late postoperative period (18–24 h) pain scores | ||||
Control | 1.15 (0.61, 1.69) | 0.70 (-0.19, 1.59) | 0.21 (-0.47, 0.88) | 0.88 (0.42, 1.35) |
0.88 (0.48, 1.28) | ESPB | 0.39 (-0.45, 1.22) | -0.73 (-1.49, 0.03) | 0.21 (-0.30, 0.72) |
0.86 (0.33, 1.38) | -0.03 (-0.58, 0.52) | INB | - | 0.15 (-0.43, 0.73) |
0.18 (-0.35, 0.72) | -0.70 (-1.25, 0.15) | -0.67 (-1.38, 0.03) | SPB | - |
0.97 (0.59, 1.35) | 0.09 (-0.33, 0.51) | 0.11 (-0.38, 0.60) | 0.79 (0.17, 1.40) | TPVB |
Estimates are presented as mean differences (95% CI). Mean differences < 0 favor the column intervention and mean differences > 0 favor the row intervention. The upper triangle displays only the pooled effect sizes of the direct comparisons that were available in our network. No direct comparison is expressed in the empty field. The lower triangle contains the estimated effect sizes for each comparison, even those for which only indirect evidence was available. ESPB: erector spinae plane block, INB: intercostal nerve block, SPB: serratus plane block, TPVB: thoracic paravertebral block.
P-scores and Ranking of the Included Blocks in Terms of Opioid Consumption and Pain Scores in the First 24 Hours Postoperative Period
Outcomes | 1 | 2 | 3 | 4 | 5 |
---|---|---|---|---|---|
Opioid consumption | TPVB | INB | ESPB | SPB | Control |
0.9963 | 0.6598 | 0.5610 | 0.2829 | 0.0001 | |
Early postoperative period (up to 6 h) pain scores | ESPB | TPVB | INB | SPB | Control |
0.7918 | 0.6937 | 0.6148 | 0.3969 | 0.0027 | |
Middle postoperative period (6–18 h) pain scores | TPVB | ESPB | INB | SPB | Control |
0.7927 | 0.7815 | 0.5066 | 0.4060 | 0.0132 | |
Late postoperative period (18–24 h) pain scores | TPVB | ESPB | INB | SPB | Control |
0.8310 | 0.7185 | 0.6895 | 0.1979 | 0.0632 |
ESPB: erector spinae plane block, INB: intercostal nerve block, SPB: serratus plane block, TPVB: thoracic paravertebral block.