Etiology of inguinal hernia: ultrastructure of rectus sheath revisited

In the last decade, in the search for abdominal-wall hernia etiology, attention has been brought to alterations in the connective tissue ultrastructure as the probable etiological factor. These may cause weakening of connective tissue, which in turn may form ground for hernia formation. To investigate this hypothesis in depth, we compared the ultrastructure of the connective tissue in hernia patients and the control group. The study group consisted of five patients with primary inguinal hernia (Nyhus II = 4, Nyhus IIIa = 1). Another five patients posted for emergency appendectomy created the control group. Tissue specimens, harvested intraoperatively from the rectus muscle sheath (RAMS) and fixed in 4% glutaraldehyde, underwent staining by the Masson, H-E and methylene blue techniques and were assessed by microscopy (light and scanning electron). The examinations showed significant differences in the rectus sheath ultrastructure. They included altered architecture, placement and quantity of collagen and elastic fibers, differences in the caliber of individual fibers and disrupted ground matter-to-fiber ratio. In patients with hernias, chaotic arrangement of collagen fibers was seen, as well as their thinning and a decrease in the general amount of elastic fibers, replaced by ground matter. Our research has shown significant differences in the structure of the RAMS between patients with hernias and healthy individuals. This supports the theory linking connective tissue alterations with the etiology of hernia, and stating that these alterations include connective tissue at locations distant from the hernia site as well, as the rectus sheath itself does not form a hernial defect.