title: Inguinal hernia: measurement of the biomechanics of the lower abdominal wall and the inguinal canal.
abstract: BACKGROUND
  The stability of the lower abdominal wall may play a considerable role in the development of inguinal hernia. Therefore, the strength of the individual wall layers needs to be quantified. Despite numerous advances in hernia repair, comparatively few systematic biomechanic and morphometric analyses have been performed. Our aim was to establish and apply a standardised procedure for testing the abdominal wall layers' stability.
  
  
  METHODS
  After dissecting the abdominal walls of 16 cadavers into separate layers, we used a spherical punch and a force transducer to investigate the forces necessary to foraminate the layer. In addition, maximum tensile-strength and suction tests and histologic morphometry were performed.
  
  
  RESULTS
  The transversalis fascia was torn up on an average of 10.5 N, the peritoneum including pre- and subperitoneal tissue on 46.6 N, the aponeurosis of obliquus internus abdominis muscle on 51.7 N, and the aponeurosis of obliquus externus abdominis muscle on 92.6 N. Tensile tests of tissue strips obtained from defined areas showed comparable results. In contrast, surgical mesh revealed values between 60 and 150 N in punching tests. Left-right comparisons, as well as comparisons of the individual areas, revealed considerable intra- and inter-individual differences.
  
  
  CONCLUSIONS
  Biological hernia repair should focus on a reinforcement of the tissue layers with the highest biomechanic stability. Reinforcement of the transversal fascia must be questioned according to our results of poor mechanical resistance.
authors.affiliation: Department of Anatomy, Johannes Gutenberg-Universität Mainz, Saarstrasse 21, 55099, Mainz, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Wolloscheck
authors.forename: A
authors.initials: A
authors.lastname: Gaumann
authors.forename: A
authors.initials: A
authors.lastname: Terzic
authors.forename: A
authors.initials: A
authors.lastname: Heintz
authors.forename: T
authors.initials: T
authors.lastname: Junginger
authors.forename: M A
authors.initials: MA
authors.lastname: Konerding
mesh_terms: D034861:Abdominal Wall / Q000473:pathology / Q000502:physiology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D001707:Biopsy, Needle; D002102:Cadaver; D005260:Female; D006552:Hernia, Inguinal / Q000601:surgery*; D006801:Humans; D007150:Immunohistochemistry; D007264:Inguinal Canal / Q000473:pathology / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D013526:Surgical Mesh; D013718:Tensile Strength