title: Systematic Review and Meta-Regression of Factors Affecting Midline Incisional Hernia Rates: Analysis of 14,618 Patients.
abstract: BACKGROUND
  The incidence of incisional hernias (IHs) following midline abdominal incisions is difficult to estimate. Furthermore recent analyses have reported inconsistent findings on the superiority of absorbable versus non-absorbable sutures.
  
  
  OBJECTIVE
  To estimate the mean IH rate following midline laparotomy from the published literature, to identify variables that predict IH rates and to analyse whether the type of suture (absorbable versus non-absorbable) affects IH rates.
  
  
  METHODS
  We undertook a systematic review according to PRISMA guidelines. We sought randomised trials and observational studies including patients undergoing midline incisions with standard suture closure. Papers describing two or more arms suitable for inclusion had data abstracted independently for each arm.
  
  
  RESULTS
  Fifty-six papers, describing 83 separate groups comprising 14,618 patients, met the inclusion criteria. The prevalence of IHs after midline incision was 12.8% (range: 0 to 35.6%) at a weighted mean of 23.7 months. The estimated risk of undergoing IH repair after midline laparotomy was 5.2%. Two meta-regression analyses (A and B) each identified seven characteristics associated with increased IH rate: one patient variable (higher age), two surgical variables (surgery for AAA and either surgery for obesity surgery (model A) or using an upper midline incision (model B)), two inclusion criteria (including patients with previous laparotomies and those with previous IHs), and two circumstantial variables (later year of publication and specifying an exact significance level). There was no significant difference in IH rate between absorbable and non-absorbable sutures either alone or in conjunction with either regression analysis.
  
  
  CONCLUSIONS
  The IH rate estimated by pooling the published literature is 12.8% after about two years. Seven factors account for the large variation in IH rates across groups. However there is no evidence that suture type has an intrinsic effect on IH rates.
authors.affiliation: University Hospital of Wales, Cardiff, CF14 4XW, United Kingdom.
authors.forename: David C
authors.initials: DC
authors.lastname: Bosanquet
authors.affiliation: University Hospital of Wales, Cardiff, CF14 4XW, United Kingdom.
authors.forename: James
authors.initials: J
authors.lastname: Ansell
authors.affiliation: Royal Gwent Hospital, Newport, NP20 2UB, United Kingdom.
authors.forename: Tarig
authors.initials: T
authors.lastname: Abdelrahman
authors.affiliation: University Hospital of Wales, Cardiff, CF14 4XW, United Kingdom.
authors.forename: Julie
authors.initials: J
authors.lastname: Cornish
authors.affiliation: Morriston Hospital, Heol Maes Eglwys, Swansea, SA6 6NL, United Kingdom.
authors.forename: Rhiannon
authors.initials: R
authors.lastname: Harries
authors.affiliation: Glan Clwyd Hospital, Rhyl, LL18 5UJ, United Kingdom.
authors.forename: Amy
authors.initials: A
authors.lastname: Stimpson
authors.affiliation: University Hospital of Wales, Cardiff, CF14 4XW, United Kingdom.
authors.forename: Llion
authors.initials: L
authors.lastname: Davies
authors.affiliation: Cardiff University School of Medicine, Cardiff, CF14 4XN, United Kingdom.
authors.forename: James C D
authors.initials: JC
authors.lastname: Glasbey
authors.affiliation: Cardiff University School of Medicine, Cardiff, CF14 4XN, United Kingdom.
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Frewer
authors.affiliation: Cardiff University School of Medicine, Cardiff, CF14 4XN, United Kingdom.
authors.forename: Natasha C
authors.initials: NC
authors.lastname: Frewer
authors.affiliation: Swansea University College of Medicine, Swansea, SA2 8AA, United Kingdom.
authors.forename: Daphne
authors.initials: D
authors.lastname: Russell
authors.affiliation: Swansea University College of Medicine, Swansea, SA2 8AA, United Kingdom.
authors.forename: Ian
authors.initials: I
authors.lastname: Russell
authors.affiliation: University Hospital of Wales, Cardiff, CF14 4XW, United Kingdom.
authors.forename: Jared
authors.initials: J
authors.lastname: Torkington
mesh_terms: D034861:Abdominal Wall / Q000601:surgery*; D058107:Abdominal Wound Closure Techniques; D006801:Humans; D015994:Incidence; D000069290:Incisional Hernia / Q000453:epidemiology* / Q000209:etiology; D007813:Laparotomy / Q000009:adverse effects / Q000379:methods*; D064887:Observational Studies as Topic; D011183:Postoperative Complications / Q000453:epidemiology* / Q000209:etiology; D016032:Randomized Controlled Trials as Topic; D012044:Regression Analysis; D012307:Risk Factors; D013536:Suture Techniques