title: Giant ventral hernia-relationship between abdominal wall muscle strength and hernia area.
abstract: BACKGROUND
  Symptoms arising from giant ventral hernia have been considered to be related to weakening of the abdominal muscles. The aim of this study was to investigate the relationship between the area of the abdominal wall defect and abdominal wall muscle strength measured by the validated BioDex system together with a back/abdominal unit.
  
  
  METHODS
  Fifty-two patients with giant ventral hernia (>10 cm wide) underwent CT scan, clinical measurement of hernia size and BioDex measurement of muscle strength prior to surgery. The areas of the hernia derived from CT scan and from clinical measurement were compared with BioDex forces in the modalities extension, flexion and isometric contraction. The Spearman rank test was used to calculate correlations between area, BMI, gender, age, and muscle strength.
  
  
  RESULTS
  The hernia area calculated from clinical measurements correlated to abdominal muscle strength measured with the Biodex for all modalities (p-values 0.015-0.036), whereas no correlation was seen with the area calculated by CT scan. No relationship was seen between BMI, gender, age and the area of the hernia.
  
  
  CONCLUSIONS
  The inverse correlation between BioDex abdominal muscle strength and clinically assessed hernia area, seen in all modalities, was so robust that it seems safe to conclude that the area of the hernia is an important determinant of the degree of loss of abdominal muscle strength. Results using hernia area calculated from the CT scan showed no such correlation and this would seem to concur with the results from a previous study by our group on patients with abdominal rectus diastasis. In that study, defect size assessed clinically, but not that measured by CT scan, was in agreement with the size of the diastasis measured intra-operatively. The point at which the area of a hernia begins to correlate with loss of abdominal wall muscle strength remains unknown since this study only included giant ventral hernias.
authors.affiliation: Department of Surgical and Perioperative Sciences, Umeå University, Umeå, S-901 87, Sweden. karin.strigard@umu.se.
authors.forename: K
authors.identifier: http://orcid.org/0000-0001-5838-9133
authors.initials: K
authors.lastname: Strigård
authors.affiliation: Department of Surgery, CLINTEC, Karolinska Institutet, Stockholm, S-171 64, Sweden, Karolinska University Hospital, Stockholm, S-171 64, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Clay
authors.affiliation: Department of Molecular Medicine and Surgery, Karolinska Institutet and Department of plastic and reconstructive surgery, Karolinska University Hospital, Stockholm, S-171 64, Sweden.
authors.forename: B
authors.initials: B
authors.lastname: Stark
authors.affiliation: Department of Surgical and Perioperative Sciences, Umeå University, Umeå, S-901 87, Sweden.
authors.forename: U
authors.initials: U
authors.lastname: Gunnarsson
authors.affiliation: Fibrinolysis Laboratory/Tissue Centre, Deptartment of Surgery, Institute of Clinical sciences, Sahlgrenska Academy, at University of Gothenburg, Sahlgrenska University Hospital/Ostra, Göteborg, S-416 85, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Falk
mesh_terms: D000009:Abdominal Muscles / Q000503:physiopathology*; D034861:Abdominal Wall / Q000503:physiopathology*; D000328:Adult; D000368:Aged; D005260:Female; D006555:Hernia, Ventral / Q000000981:diagnostic imaging* / Q000503:physiopathology* / Q000601:surgery; D059685:Herniorrhaphy; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D014057:Tomography, X-Ray Computed
keywords: Abdominal muscle strength; Biodex; Giant ventral hernia; Hernia area