Recurrency After Inguinal Herniorraphy With Bi-layer Mesh (BLM)
Condition: Inguinal Hernia
MeSH terms: Hernia, Inguinal
Study type: Observational

Summary: 
      Aim The overall aim with this study is to improve outcome after inguinal hernia repair (IHR).
      It is not known today if a re-operation due to recurrence after bi-layer mesh IHR is more
      complicated than compared with the golden standard method.

      Method This project is a registry study. The National hernia register (Svenskt bråckregister,
      SBR) which started in 1992 include data that cover nearly 100% of all the country's hernia
      operations.

      Patient data are collected from SBR. Patients who at the time of surgery were between 18-75
      years of age and operated on due to primary inguinal hernia with any of the two mentioned
      techniques between 1992-2012 are eligible
    

Detailed description: 
      Background Surgical repair for inguinal hernia is the most common surgical procedure in the
      world. Since the introduction of repair with mesh reinforcement, relapses have decreased
      significantly. Recurrence of inguinal hernia affects only 1-2% after inguinal hernia repair
      (IHR) [1] and is no longer considered to be a big problem. One problem is that a large
      proportion of patients undergoing surgery develop chronic pain from the surgical area [2-4].
      New meshes, with new design and new materials are continuously being introduced, with the aim
      of reducing the incidence of chronic pain. One of the most common meshes in use today is the
      so-called "double-mesh" (bi-layer mesh) [1, 5]. Several studies have shown that bi-layer mesh
      can lead to some gains for the patient initially after surgery, but there is no scientific
      evidence available that suggest that bi-layer mesh is superior the traditional tension-free
      mesh repair in the long term [6, 7]. Several reports have shown that bi-layer mesh repair
      give results as good as the golden standard method, where a single sheet mesh is used.

      The surgical technique differ somewhat with respect to which layer of the abdominal is being
      used [8], when using a bi-layer- or a single sheet mesh. With the bi-layer mesh you use the
      abdominal layer that is usually used (the pre-peritoneal space) in case of re-operation due
      to recurrence after open mesh repair. Re-operation after bi-layer mesh IHR is incompletely
      studied and it is unclear if this is a more difficult surgical procedure compared with
      re-operation for recurrence after standard IHR.

      Aim The overall aim with this study is to improve outcome after IHR. It is not known today if
      a re-operation due to recurrence after bi-layer mesh IHR is more complicated than compared
      with the golden standard method.

      Method This project is a registry study. The National hernia register (Svenskt bråckregister,
      SBR) which started in 1992 include data that cover nearly 100% of all the country's hernia
      operations.

      Patient data are collected from SBR. Patients who at the time of surgery were between 18-75
      years of age and operated on due to primary inguinal hernia with any of the two mentioned
      techniques between 1992-2012 are eligible.

      Statistics Parametric and non-parametric statistical methods for descriptive analysis will be
      used for comparison within and between the groups. Students t-test.

      Power calculation The primary outcome variable for this registry study is the prevalence of
      recurrence after bi-layer mesh IHR. This is incompletely mapped. There is no need of a power
      calculation because the material of the registry is very large and any relevant differences
      between the groups should easily be detected.

      Gain of knowledge The results of the study could show that either method of IHR (eg bi-layer
      mesh) is less suitable in surgical repair of inguinal hernia, which could be troublesome for
      those patients who had surgery with the method.
    

Observational model: Cohort
Time perspective: Retrospective
Sampling method: Non-Probability Sample
Study population: 
        patinets with relapse after inguinal hernia surgery