title: The etiology of indirect inguinal hernia in adults: congenital or acquired?
abstract: OBJECTIVE
  During hernioplasty focal thickened tissue containing smooth muscle is found at the neck of the hernia sac in most patients with indirect inguinal hernia. These thickenings may be related to the processus vaginalis and reveal the etiology of indirect inguinal hernia.
  
  
  METHODS
  The study included 50 male adults with indirect inguinal hernia and 50 male adults with direct inguinal hernia, all of them were initial cases. Hernioplasty and excision of the hernia sac were performed, meanwhile anatomical features of the hernia sac and the spermatic cord were recorded, then followed by histological investigation of the hernia sacs.
  
  
  RESULTS
  Focal thickenings were observed at the neck of the hernia sac in 88 % of adults with indirect inguinal hernia. Dense adhesion between the hernia sac and the spermatic cord was found where the thickening located. Histological examination identified smooth muscle cells in 57 % of the thickened tissues. No similar findings were observed in patients with direct inguinal hernia.
  
  
  CONCLUSIONS
  The focal thickening which contains smooth muscle tissue may be remnant of the processus vaginalis after its obliteration. In other word, the presence of the thickening means that fusion of the processus vaginalis has previously taken place. Thus, most indirect inguinal hernias in adults may represent acquired diseases.
authors.affiliation: Department of Gastrointestinal Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China.
authors.forename: Z P
authors.initials: ZP
authors.lastname: Jiang
authors.affiliation: Department of Gastrointestinal Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China.
authors.forename: B
authors.initials: B
authors.lastname: Yang
authors.affiliation: Department of Gastrointestinal Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China.
authors.forename: L Q
authors.initials: LQ
authors.lastname: Wen
authors.affiliation: Department of Gastrointestinal Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China.
authors.forename: Y C
authors.initials: YC
authors.lastname: Zhang
authors.affiliation: Department of Gastrointestinal Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China.
authors.forename: D M
authors.initials: DM
authors.lastname: Lai
authors.affiliation: Department of Gastrointestinal Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China.
authors.forename: Y R
authors.initials: YR
authors.lastname: Li
authors.affiliation: Department of Gastrointestinal Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, Guangdong, China. jzpsums@126.com.
authors.forename: S
authors.initials: S
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D006552:Hernia, Inguinal / Q000209:etiology* / Q000473:pathology* / Q000601:surgery; D059685:Herniorrhaphy / Q000009:adverse effects*; D006801:Humans; D007264:Inguinal Canal / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009130:Muscle, Smooth / Q000473:pathology; D010537:Peritoneum / Q000473:pathology; D013085:Spermatic Cord / Q000473:pathology*; D013737:Testis / Q000473:pathology
keywords: Etiology; Indirect inguinal hernia; Processus vaginalis; Smooth muscle