Data Extraction and Quality assessment
Articles retrieved from the systematic search were exported to EndNote Reference Library software, and any duplicates found were discarded. The remaining articles were initially screened based on abstract and title, then a review of the entire text was conducted to assess relevance. Screening of the articles was distributed amongst two reviewers, (M.H, H.M), and any inconsistencies were resolved by discussion till consensus or by the third reviewer (A.R.S.S). The following baseline characteristics were extracted onto an online Microsoft Excel Spreadsheet: study characteristics (First author’s name along with publication year, study design, number of patients) population characteristics (patient age in years, male gender percentage, Body mass index (BMI)(kg/m2), ASA score, mean operation time, subgroups of dosage of drug). The baseline characteristics are given in