DOI: https://doi.org/10.21203/rs.2.22941/v1
Background: Ultrasound-guided Erector Spinae Plane Block (ESPB) has been increasingly applied in patients for postoperative analgesia. Its safety and effectiveness remain uncertain. This meta-analysis aimed to determine the clinical safety and efficacy of ultrasound-guided ESPB in adults undergoing general anesthesia (GA) surgeries.
Methods: A systematic databases search was conducted in PubMed, Embase, and the Cochrane Library for randomized controlled trials (RCTs) comparing ESPB with control or placebo. Primary outcome was iv. opioid consumption 24 h after surgery. Standardized mean differences (SMDs) or risk ratios (RRs) with 95% confidence intervals (CIs) were calculated with a random-effects model.
Results: A total of 11 RCTs consisting of 540 patients were included. Ultrasound -guided ESPB showed a reduction of iv. opioid consumption 24 h after surgery (SMD=-2.15; 95% confidence interval (CI) -2.76 to -1.5,p<0.00001), pain scores at 1st hour (SMD=-0.97;95% CI -1.84 to -0.1,p=0.03) and pain scores at 6th hour (SMD=-0.64,95% CI -1.05 to -0.23,p=0.002), Also, it lessened the number of patients who required postoperative analgesia ( RR=0.41,95% CI 0.25 to 0.66,p=0,0002) and time to first rescue analgesia (SMD=4.56,95% CI 1.89 to 7.22, p=0.0008). Differences were not significant with the pain score at 12th hour,24th hour and postoperative nausea and vomiting (PONV).
Conclusions: Ultrasound-guided ESPB provides postoperative analgesic efficacy in adults undergoing GA surgeries with no increase in PONV.
Ultrasound-guided Erector Spinae Plane Block (ESPB) is a novel regional anesthesia technique that local anesthetic(LA) injection is performed into the fascial plane situated between the transverse process of the vertebra and the erector spinae muscles, and it works by infiltration of LA into the thoracic paravertebral space[1].With the ease of complications and relatively security, its clinical application is increasing. Followed by first description in providing thoracic analgesia by Tulgar[2],it has been reported subsequently to relief both acute and chronic pain in various case reports and cadaveric studies[3–7].Nowadays, there are published a number of randomized controlled trials (RCTs) of ultrasound-guided ESPB for postoperative analgesia, owing to the modest sample size and inconsistent conclusion, We therefore conducted a meta-analysis to examine the clinical safety and efficacy of ultrasound-guided ESPB among adults undergoing general anesthesia (GA) surgery.
This systematic review and meta-analysis of RCTs was reported abiding by the Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) statement[8].It was conducted base on the statement of the Cochrane Handbook for Systematic Reviews of Interventions[9]. No formal protocol was registered for this meta-analysis.
PubMed, EMBASE, and the Cochrane Library were searched from inception to August 2019 with no language restriction. The search terms used were:('erector spinal plan block' OR 'erector spinal block' OR 'erector spinal plan blocks' OR 'erector spinal blocks'). The bibliographies of included trials were manually searched for any eligible trials missed by the electronic search. This process was conducted iteratively until no extra reference could be verified.
Two of us independently performed the preliminary data search, after removing duplicate references, the titles and abstracts were screening for the eligible trials. We included all RCTs in adults who were undergoing GA surgery with the intervention of ultrasound-guided ESPB regardless the anaesthetic drug, volume and concentration administered. The control group should be conducted with a sham technique with saline or placebo. Trials were excluded for the following criteria: animal or cadaveric studies; reviews; did not report opioid consumption or pain scores as an outcome; Any discrepancies were resolved by double-check of the source data and discussion with coauthors.
Data were collected for each eligible trial on first author, publication year, patient number, patient characteristics, American Society of Anesthesiologists (ASA) physical status, surgical procedure, ESPB group (position, dosage and concentration), control group (placebo or no invention) and outcome data. Any uncertainty arose were figured out though a consensus achieved. For continuous data, we calculated mean and SD, if not provided, we contacted authors. Median and interquartile range were seen as means and standard deviation(SD) approximately as follows if we did not get reply: the median was considered equal to the mean, and the SD was calculated as the interquartile range divided by 1.35[10]. The primary outcome of this meta-analysis was i.v. opioid consumption during the 24 h postoperatively, the secondary outcomes included pain scores at the 1st hour,6st hour,12st hour,24st hour following surgery, no. need rescue analgesia requirement, time to first rescue analgesic and postoperative nausea or vomiting (PONV).
Two authors (JH and J-C l) evaluated the methodological quality of the trials according to the Cochrane risk-of-bias tool[11]. Each item was categorized as having a ‘low’, ‘unclear’, or ‘high’ risk of bias. Any uncertainty arose were resolve by discussion between two researches until a consensus was achieved.
The relative risks (RRs) with 95% confidence intervals (CIs) was calculated for dichotomous outcome data. For continuous outcome data, standardized mean differences (SMDs) with 95% Cis were reported. A random effects model was selected to acquire the most conservative effects estimate. An I² statistic of 25%-50% were defined as low heterogeneity, an I² statistic of 50%-75% were described as moderate heterogeneity, and those with an I² statistic of > 75% were considered as high heterogeneity[12], The heterogeneity was substantial when an I² value was over 50%. Subgroup analyses for the first outcomes based on using a patient-controlled analgesia device (PCA) or not was planned. Publication bias was evaluated using funnel plots. Statistical analyses were calculated using the Review Manager Version 5.3 (Nordic Cochrane Centre, Cochrane Collaboration)
Study identification and characteristics
A total of 675 studies were obtained by the literature search. No further citations were found by hand searching.211 records were excluded for duplicate studies and a further 449 records removed by screening titles and abstracts. 15 full text publications remained were scrutinized for conclusive identified.4 of them were excluded because 2 did not report data of interest[13, 14], one was currently ongoing study[15],one was review article[16].Finally,11 RCT[17-27] satisfied our inclusion criteria. A flowchart of the literature search is shown in（Fig. 1.）The main characteristics of the 11 RCTs included are presented in Table 1.
Quality Assessment
Four trials at a low risk of bias, and 7 trials at an unclear risk of bias. The randomisation procedure was adequately generated in 10 trials, the concealment of treatment allocation was described in 6 trials. Since we subjectively judge the outcome measurement was little prone to be changed by lacking of blinding, all RCTs included were classified as low risk of bias at blinding of outcome assessments. Assessment of risk-of-bias summary of all RCTs are presented in (Fig.2).
Primary outcomes
All RCTs reported data for 24 h postoperative iv. opioid consumption in the study patients. Pooled analysis showed a significant reduction of opioid requirement with ESPB (95% CI -2.76 to -1.53; P<.00001; Fig3). There was substantial heterogeneity in the overall analysis of 24 h opioid consumption (P for heterogeneity<.00001; I²=88%). The heterogeneity remained when subgroup analysis base on the PCA administration was conducted. (Fig.4) Publication bias by appraisal of the funnel plot (Fig.5)
Secondary outcomes
Ultrasound-guided ESPB significantly decrease pain scores at the 1 h(95% CI -1.84 to -0.1; P=.03,I²=89%) and 6 h[95% CI -1.05 to -0.23; P=.002,I²=65%).Furthermore, No. need rescue analgesia requirement (95% CI 0.25 to 0.66; P=.0002, I²=67%) and time to first rescue analgesic (95% CI 1.89 to 7.22 ; P=.0008,I²=95%) was lower in the ESPB group. However, pain scores of the 12 h(95% CI -0.66 to 0.33; P=.51,I²=76%),24 h(95% CI -1.78 to 0.12; P=.09,I²=94%) and PONV(95% CI 0.20 to 1.00; P=.05,I²=84%) did not achieve statistical significant significance. The outcomes of the selected trials are reported in Table 2.
The main finding of this meta-analysis is that performing ESPB constitutes an effective postoperative analgesic for reducing opioid consumption 24 hours after surgery, pain scores at 1 h and 6 h following surgery. Furthermore, it has been shown there is a significant reduction on patients who need rescue analgesia and prolongation in the time to first request of rescue analgesia. However, PONV was not significantly lower in patients treated with ESPB.
The significant decrease postoperative opioid is of great value for patients to enhance comfortable feelings and recovery following surgery. PONV is one of opioid dose-related side effects, which is not conducive to the rapid recovery after surgery[28], one study reported the use of postoperative opioids is related to PONV with a high rate of 79% among 4 risk factors[29]
Therefore, we hypothesized that a decrease in opioid use could lessen PONV, however, on the contrary, the PONV difference was not statistically significant while opioid consumption and rescue analgesia reduced in our meta-analysis. The most likely Interpretation for this result was the PONV prophylaxis intraoperatively by applying antiemetic drugs such as iv. tropisetron or dexamethasone.
Despite ESPB has been successfully applied in postoperative analgesia with few adverse reactions, the mechanism of ESPB is still controversial. Altinpulluk EY[3], Forero M[2] and Chin KJ[30]observated an extensive spread to ventral rami and dorsal rami in the paravertebral space when ESPB is utilized, at the same time, Aponte A[31] found posterior rami of spinal nerves was diffused, while no spread to the paravertebral space and anterior rami. Elsharkawy H[32] described the paravertebral space infiltrated was not observed too. The optimum concentration and volume of LA in ESPB have not been described in the clinical guideline. Only one RCT[33] make a comparison between different concentration of bupivacaine. Therefore, future research should focus on investigating the pattern of LA spread and impact of LA concentration and volume in ESPB.
Several factors may account for the extensive heterogeneity of the analysis. First, various severity of illness and surgery types (open and endoscopic surgeries) are undoubtedly play an important role in heterogeneity, Second, opioid (fentanyl, tramadol, morphine and so on) doses were not converted to morphine-equivalent doses which could make a wide dissimilarity between the data. Besides, utilizing supplementary analgesics such as paracetamol[25, 26]added an extra heterogeneity, Last, a short of clinical studies to use this technique make a difference among those studies.
Several notable limitations should be considered when interpreting the results. Firstly, the trials included have a modest sample size which could magnify the treatment effect. Secondly, the substantial heterogeneous make our results less convincing. Furthermore, owing to all patients were under GA surgeries, sensory blocking could not be evaluated adequately to detect potential block failures in all trails included.
In summary, ESPB block provide an effective analgesic and serve as a promising alternative option for postoperative pain management. However, the results should be interpreted cautiously since insufficient evidence, although accumulating. Further large-scale RCTs are required to support our results.
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Competing interests
The authors declare that they have no competing interests
Funding
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Authors’ contributions
JH and JC L participated in the entire procedure including the design and coordination of the study, the literature search, data extraction, performed the statistical analysis, drafted the manuscript, revised submitted the manuscript. All authors read and approved the final manuscript.
Acknowledgements
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Authors’ information
First Affiliated Hospital of Guangxi Medical University,6 shuangyong Road, Nanning 530021, Guangxi Zhuang Autonomous Region, P.R. china.
Jiao Huang, Jingchen Liu
Corresponding author: Jingchen Liu
ESPB: erector Spinae Plane Block;
GA: general anesthesia;
LA: local anesthetic;
RCTs: randomized controlled trials;
PRISMA: Preferred Reporting Items for Systematic Reviews and Meta Analyses;
RCTs: American Society of Anesthesiologists;
PONV: postoperative nausea or vomiting RRs: relative risks;
SD: standard deviation;
SMDs: confidence intervals (CIs) standardized mean differences;
PCA: patient-controlled analgesia device
Table1: main characteristics of randomized controlled trials included in the meta-analysis.
|
|
No. Of patients
|
Surgical procedure |
ASA |
Patient Characteristics |
ESPB group |
Control group |
GA induction |
|
Abu Elyazed
|
60(30/30) |
Midline epigastric
|
I–II |
18–65 years of age |
Bilateral ultrasound- Guided ESPB at the level of T7 transverse process using 10 mL of bupivacaine 0.25% on each side |
Bilateral sham
|
Propofol 2–2.5 mg/kg and fentanyl 1μg/kg,
0.15mg/kg |
|
Tulgar et al (2018) |
30(15/15) |
Laparoscopic
|
I–II |
18–65 years of age |
Bilateral ultrasound- Guided ESPB at the level of T9 transverse process using 10 mL of bupivacaine 0.375% on each side |
Received no
|
Propofol 2–3 mg kg−1,fentanyl 100 μg and rocuronium bromide 0.6 mg kg−1 |
|
Gürkan et al (2018) |
50(25/25) |
Elective breast
|
I–II |
Aged 20–65 years |
Ultrasound (US)-guided ESP block with 20 ml 0.25% bupivacaine
|
Received no
|
Propofol (2–3 mg kg−1) and fentanyl (2 mg kg−1) iv, rocuronium 0.6 mg kg−1 |
|
Singh et al(2019) |
40(20/20) |
Elective lumbar
|
I–Ⅲ |
18–65 years of age |
Ultrasound (US)-guided ESP block with total 20 ml 0.5% bupivacaine at the T10 vertebral level |
Received no
|
Propofol 2 to3 mg/kg, morphine 0.1 mg/kg
|
|
Gürkan et al (2019) |
50(25/25) |
Elective unilateral
|
I–II |
Aged 18–65 years |
Ultrasound (US) guided ESP block with 20 ml
|
Received no
|
Propofol (2–3 mg kg−1 )
(2 μg kg−1 ) iv and rocuronium 0.6 mg kg−1
|
|
Singh et al (2019) |
40(20/20) |
Modified radical
|
I–II |
Female patients
|
Ultrasound (US)-guided ESP block with total 20 ml 0.5% bupivacaine at the T5 vertebral level |
Received no
|
Propofol 2–3 mg kg−1 ，
0.1 mg kg−1 |
|
Aksu et al (2019) |
46(23/23) |
Laparoscopic
|
I–II |
20–75 years of age |
Ultrasound (US) guided ESP block with 20 ml
level |
Received no
|
Propofol (2-3 mg kg-1) and fentanyl (2 mg kg-1) iv and Rocuronium (0.6 mg kg-1)IV |
|
Ciftci et al (2019) |
60(30/30) |
Video-Assisted
|
I–II |
18–65 years of age |
Ultrasound guided Bilateral ESP block with20ml of 0.375% bupivacaine at the T5 vertebral level |
Received no
|
Propofol (2-2.5 mg/kg)
(1-1.5 mg/kg) and rocuronium bromide (0.6mg/kg) |
|
Yayik et al (2019) |
60(30/30) |
Lumbar Spinal
Surgery |
I–Ⅲ |
18–65 years of age |
Ultrasound guided Bilateral ESP block with 0.25% bupivacaine 20 mL at the L3 vertebral level |
No intervention
|
2 mg/kg IV propofo，
|
|
Hamed et al (2019) |
60(30/30) |
Abdominal
|
I–Ⅲ |
Women aged 40–70 years old and weighed 50–90 kg |
Ultrasound-guided ESPB at T9 vertebrae level with 20 ml bupivacaine 0.5%. |
Underwent the
|
Fentanyl 2 mcg.kg−1 and propofol 2 mg.kg1 Followed by atracurium 0.5 mg.kg−1 |
|
40(20/20) |
Hip and proximal
surgery |
I–Ⅲ |
Aged 18–65 years |
Ultrasound-guided ESPB at T9 vertebrae level with
|
Underwent the
|
Propofol 2-3mg/kg,
|
Table2: Outcome data of RCTs included in the meta-analysis.
|
Outcome |
Studies include |
RR or Std.mean differance [95%CI] |
P-value for
|
P-value for
|
I² test for
|
|
Opiod consumption in the first 24 hour(mg) |
17-27 |
-2.15[-2.76,-1.53] |
<0.00001 |
<0.00001 |
88% |
|
VAS/NRS scores at the 1st hour |
17,18,20,24,27 |
-0.97[-1.84,-0.1] |
0.03 |
<0.00001 |
89% |
|
VAS/NRS scores at the 6th hour |
17,18,20,21, 24,25,27 |
-0.64[-1.05,-0.23] |
0.002 |
0.01 |
65% |
|
VAS/NRS scores at the 12th hour |
17,18,20,21, 24,25,27 |
-0.16[-0.66,0.33] |
0.51 |
0.0008 |
76% |
|
VAS/NRS scores at the 24th hour |
17-21,25,27, |
-0.83[-1.78,0.12] |
0.09 |
0.0001 |
94% |
|
Rescue analgesia requirement(n) |
18,19,22,23,26 |
0.41[0.25,0.66] |
0.0002 |
0.006 |
67% |
|
Time to first rescue analgesic(min) |
17,23,26 |
4.56[1.89,7.22] |
0.0008 |
0.00001 |
95% |
|
POVN( postoperative nausea and vomiting ) |
17-19,21,24-27 |
0.45[0.20,1.00] |
0.05 |
<0.00001 |
84% |