When conducting the Shouldice procedure the 4-layer suture of the transversalis fascia is usually done with Prolene worldwide. At the Shouldice hospital the wire has originally been used for these augmentation. During the last decade several Shouldice Surgeons started to use the Prolene due to occasional delivery problems of the wire from Germany.

The 1-year- recurrence rate at the Shouldice hospital is 1,15% (mainly wire-use). The published 1-year recurrence rate in Europe is 2%.

As quality assessment, this project intends to evaluate these two options for suturing (wire vs Prolene) in the elective inguinal hernia patient in terms of 1-year recurrence rate. The population of focus will be those who had a primary or secondary inguinal hernia operation at Shouldice Hospital and the project is estimated to take 3 months.

a. Study design A total of 1400 patients (n=700 with wire; n=700 with Prolene) who underwent Shouldice surgery at Shouldice Hospital will be contacted by telephone. They will be asked whether a relapse occurred after their surgery.

Sample size calculation:

The 1-year recurrence rate at Shouldice Hospital is 1.15% (mainly wire use). The published 1-year recurrence rate in Europe is 2% [1-3]. Statistics: non-inferiority: delta for non-inferiority (defined equivalence range) = 1%. Total N = 1120 (0% dropout), with 20% dropout: N = 1400.) The same number of patients will be analyzed with regard to Shouldice repair due to a first relapse (time period of data extraction 2019-2021).

Since over 6000 hernias are operated annually, a consecutive data extraction of patients operated in 2021 will be performed.

Inclusion Criteria:

• Adult patients of all sexes who have undergone inguinal hernia surgery in Shouldice technique.

Exclusion Criteria:

• Hernia repair using a mesh

Adult patients of all sexes who have undergone inguinal hernia surgery in Shouldice technique.