Evidence Review Process - ESRA
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Inguinal Hernia Repair 2019

Evidence Review Process

An explanation of PROSPECT methodology and Working Group processes can be found at the following link: http://esraeurope.org/prospect-methodology

For the open inguinal hernia repair review, the Subgroup members were:

  • S Coppens1*
  • J Gidts1*
  • P Huynen1
  • M Van de Velde1†
  • GP Joshi2
  1. Department of Cardiovascular Sciences, Section Anesthesiology, KU Leuven and University Hospital Leuven, Belgium.
  2. Department of Anesthesiology and Pain Management, University of Texas Southwestern Medical Center, Dallas, Texas, USA.

* S Coppens and J Gidts equally share first authorship

† Corresponding author

Open inguinal hernia repair literature search

  • Systematic review of the literature associated with analgesia after open inguinal hernia repair between January 1st 2009 and August 31st 2019.
  • The following databases were searched: the US National Library of Medicine Database (MEDLINE), the Excerpta Medica database (EMBASE), PubMed, and Cochrane Databases (Cochrane Central Register of Controlled Trials, Cochrane Database of Abstracts or Reviews of Effects, Cochrane Database of Systematic Reviews) (Search strategy).
  • Included studies were RCTs in English assessing postoperative pain after open inguinal hernia repair using analgesic, anaesthetic or surgical interventions.
  • Of 620 records identified, 324 were screened and 203 full-text articles were assessed for eligibility.
  • 37 RCTs met the inclusion criteria for qualitative analysis (Summary of literature selection; Included studies).
  • 166 articles were excluded after full-text screening.
  • The reasons for exclusion were: laparascopic procedure (n=49); focus on chronic pain (n=45); no full text (n=14); paediatric population (n=18); no focus on pain scores (n=40).

Literature search history

  • The PROSPECT recommendations for pain management after open inguinal hernia repair have been published previously (Joshi 2012), based on a literature search conducted between January 1966 and March 2009. That search identified 79 studies meeting the inclusion criteria.
  • The first PROSPECT recommendations for pain management after hernia repair (open or laparoscopic) were based on a systematic review of the literature from 1966–January 2004 (Archive: Herniorraphy 2004).

Assessments of the quality of study methodology and reporting

All included studies were assessed for quality according to PROSPECT methodology (Joshi 2019, http://esraeurope.org/prospect-methodology). The study quality assessments for open inguinal hernia repair are summarised here: Quality assessments and level of evidence assigned to included trials.

The majority of the studies included in this systematic review were determined to be of high quality.

  • Data extraction and data analysis for open inguinal hernia repair adhered to the PROSPECT methodology (Joshi 2019, http://esraeurope.org/prospect-methodology).
  • Pain intensity scores were used as the primary outcome measure.
  • In this study, we defined a change of more than 10 mm on the VAS or NRS as clinically relevant.
  • The effectiveness of each intervention for each outcome was evaluated qualitatively by assessing the number of studies showing a significant difference between treatment arms (p < 0.05 as reported in the study publication).
  • A meta-analysis was not performed due to heterogeneity in study design and result reporting, restricting pooled analysis.

Recommendations were made according to PROSPECT methodology (Joshi 2019, http://esraeurope.org/prospect-methodology). This involved a grading of A–D according to the overall level of evidence, as determined by the quality of studies included, consistency of evidence and study design: Relationship between quality of the study and levels of evidence (LoE) and grades of recommendation.

The proposed recommendations were sent to the PROSPECT Working Group for review and comments and a modified Delphi approach was used. Once a consensus was achieved the lead authors drafted the final document, which was ultimately approved by the working group.

The limitations of this review are related to those of the included studies:

  • Considerable heterogeneity between studies with regards to dosing regimens and route of administration as well as timing of pain assessments
  • The small size of most studies has the potential for estimation effect and does not provide a safety profile of the analgesic interventions
  • In a majority of the studies the analgesic intervention was not evaluated against an optimised multimodal analgesic regimen.

The AGREE II instrument (Brouwers 2010) is used internationally to assess the methodological rigour and transparency of practice guidelines. As far as possible, the methodology of the PROSPECT Open Inguinal Hernia Repair review meets the requirements of ‘Domain 3: Rigour of development’ of the AGREE II instrument:

  • Systematic methods were used to search for evidence
  • The criteria for selecting the evidence are clearly described
  • The strengths and limitations of the body of evidence are clearly described
  • The methods for formulating the recommendations are clearly described
  • The health benefits, side effects, and risks have been considered in formulating the recommendations
  • There is an explicit link between the recommendations and the supporting evidence
  • The guideline has been externally reviewed by experts prior to its publication. (The evidence and recommendations are made available on the website after peer review and publication)
  • A procedure for updating the guideline is provided. (Methodology is provided so that the systematic review can be updated as required).