Skin graft donor site management is one of the most critical and challenging issues in clinical care after burn injury. Studies have shown that multimodal pain management is also needed for burns that require autologous skin grafting. Also, by controlling pain after skin graft harvest, the need for readmission can be extended, hospitalization time extended, total narcotic use reduced, and costs reduced [1-3]. The use of regional nerve blocks in combination with narcotics can be beneficial in pain management; Studies have shown that Peripheral nerve blocks can lead to hospital stays, reduced use of narcotics, and lower pain scores [4-6]. Few studies have been performed to evaluate regional anesthesia (RA) at skin graft donor-site pain. The results of RA techniques on pain relief and narcotic consumption are challenging and should be evaluated . Hence, the present study's purpose was to evaluate the efficacy and outcome of RA in a population of adult burn injury patients to diminish narcotic consumption .
Systematic literature searches were performed by May 2021 in electronic databases including PubMed, Cochrane Library, Embase, Endnote X8 software was used for reference, PubMed database was searched based on mesh expressions. The present study is based on the critical considerations of the PRISMA  statement and used to achieve the results of the PICO strategy (Table 1).
Inclusion criteria: Randomized controlled trials (RCT) studies, prospective and retrospective cohort studies, adult burn injury patients, and published in the English language. In vitro studies, reviews, animal studies and clinical studies, and incomplete data were excluded [10-12].
Data Extraction and method of analysis
Cochrane Collaboration  and MINORS tools were used to evaluate the quality of RCT and Non-RCT studies; Thus, in the Cochrane Collaboration tool, scores were considered 1 for low risk and 0 for high and uncertain risk; A score higher than 4 indicated the high quality of the study. A score above 16 in the MINORS instrument indicated higher study quality .
Two browsers independently reviewed the data of the selected studies and were then reviewed and validated by the third browser. Meta-analysis was performed using STATA software version 16; 95% confidence interval (CI) of the mean difference with the fixed-effect model and inverse variance method was performed [15-17]. The fixed-effect model and Mantel-Hansel method were used to investigate the risk difference. Random effects were used to evaluate the heterogeneity between studies; The I2 coefficient indicates heterogeneity; If this number is above 50%, it indicates high heterogeneity in the studies (p<0.05), and vice versa, it indicates low heterogeneity (p> 0.05) [18-20].
The initial search of the databases was performed with the desired keywords, at this stage, 24 articles were found, one article was repeated twice, which was removed from the study, and the abstract of 23 studies was reviewed; Studies that did not meet the inclusion criteria or included exclusion criteria were excluded from the study. Finally, the full text of 9 studies was reviewed, and studies that had incomplete data or were not in line with the purpose of the present study were excluded from the study. Finally, three articles were selected (Figure 1).
Three studies (RCT study and two prospective cohort studies) were included. The number of patients in the RA and control group was 47, a total of 94. 94 participants requiring split-skin grafting for burn injuries between 15-18% total body surface areas were randomized to control (74 participants) or intervention group (47 participants) (Table 2).
According to Cochrane Collaboration tool, one study  had an overall score of 5/6, also according to MINORS score, one study had an overall score of 21/24 , and one study had an overall score of 24/24 . This result revealed a low risk of bias in all studies.
Mean difference of cumulative Morphine requirements was -49.01 (MD, -49.01 95% CI 56.36, -41.67. p-value= 0.00) and heterogeneity was high (I2=95.35%; P =0.00). There was a statistically significant difference between continuous RA and the control group of cumulative Morphine requirements (Figure 2). Mean difference of cumulative Morphine requirements was -49.07 (MD, -49.01 95% CI 56.14, -42.00. P-value=0.00) and heterogeneity was high (I2=95.21%; P =0.00). There was a statistically significant difference between single-shot RA and the control group of cumulative Morphine requirements (Figure 3). This result showed both RA had statically significantly lower total morphine consumption.
The difference of Donor Site Visual Analog Scale (VAS) Pain Scores was 0.37 (RR, 0.37 95% CI 20, 54. P-value= 0.00) and heterogeneity was low (I2<0%; P =0.78). There was a statistically significant difference between continuous RA and the control group of pain scores (Figure 4). In all studies, Donor Site VAS pain score in the continuous RA group reported 0. The results demonstrated continuous RA improved analgesia [24-26].
The difference of Dynamic Visual Analog Scale (VAS) Pain Scores was 0.50 (RR, 0.50 95% CI 0.30, 0.70. P-value = 0.00) and heterogeneity was low (I2<0%; P-value=0.70). There was a statistically significant difference between continuous RA and the control group of pain scores (Figure 5). The difference of Dynamic Visual Analog Scale (VAS) Pain Scores was 0.37 (RR, 0.37 95% CI 0.14, 0.59. P P-value=0.00) and heterogeneity was low (I2<0%; P-value=0.70). There was a statistically significant difference between single-shot RA and the control group's pain score (Figure 6). RA appears to decrease pain during hip flexion and dynamic movement .
Few studies have been performed on RA skin graft donor-site pain management [31-33]. The present study was conducted to evaluate the effectiveness and outcome of RA in the population of adult burn injury patients to diminish narcotic consumption and pain . In the present study, only three studies were found that were steady with the reason of the study, the low risk of bias reported according to RCT and Non-RCT tools [35-37]. Still, in some results, high heterogeneity was observed between studies. The present study results showed that RA would significantly reduce pain and narcotic consumption compared to the control group . Other studies have examined variables such as using a local anesthetic cream and tumescent solution before transplantation [39-41]. Burn injuries cause severe pain and predispose the patient to increased narcotic consumption to reduce pain . One of the goals of RA is to reduce narcotic consumption. Studies reported RA has side effects such as toxicity of anesthesia, temporary muscle weakness, and catheter-related infections. Advance studies are required to evaluate RA and length of hospital stay.
This study showed that RA can reduce pain in burns. Some studies have shown that the average of patients with burns is around 8.8 to 12.3%. Also, the average length of hospital stays for patients with 10% average TBSA was 14 days. In the present study, accurate tools were used to evaluate the low-quality studies. Further studies in this area are needed to provide strong evidence. Regional anesthesia is an essential critical issue of pain management in reconstructive burn surgery. The result showed RA reduced total morphine consumption and pain. Further studies, especially RCT studies, are required to supply more grounded proof by assist study.
We would like to thank all the people who helped in preparing and compiling the article and collecting the available data.
How to cite this article: Hamidreza Alizadeh Otaghvar, Nastaran Khodakarim, Amir Molaei, Mahdy Saboury*, Ali Akbar Jafarian, Marzieh Delavar. Medical evaluation of the effectiveness and outcome of regional anesthesia in burn populations to reduce drug use: a systematic review and meta-analysis. Eurasian Chemical Communications, 2022, 4(6), 473-480. Link: http://www.echemcom.com/article_147128.html
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