title: Skip segment Hirschsprung's disease: a systematic review.
abstract: OBJECTIVE
  Hirschsprung's disease is characterised by the congenital absence of ganglion cells beginning in the distal rectum and extending proximally for varying distances. 'Zonal aganglionosis' is a phenomenon involving a zone of aganglionosis occurring within normally innervated intestine. 'Skip segment' Hirschsprung's disease (SSHD) involves a 'skip area' of normally ganglionated intestine, surrounded proximally and distally by aganglionosis. While Hirschsprung's disease is believed to be the result of incomplete craniocaudal migration of neural crest-derived cells, the occurrence of SSHD has no clear embryological explanation. The aim of this study was to perform a systematic review of SSHD, reported in the literature between 1954 and 2009, in order to determine the clinical characteristics of this rare entity and its significance.
  
  
  METHODS
  The first reported case of SSHD was published in 1954. A systematic review of SSHD cases in the literature, from 1954 to 2009, was carried out using the electronic database 'Pubmed'. Detailed information was recorded regarding the age, gender, presenting symptoms and location of the skip segment in each patient.
  
  
  RESULTS
  24 cases of SSHD have been reported in the literature to date. 18/24 (75%) of these cases were males and 6/24 (25%) were females. Of these, 22/24 (92%) were cases of total colonic aganglionosis (TCA), and 2/24 (8%) were rectosigmoid Hirschsprung's disease. Of the 22 TCA cases, 9 (41%) had a skip segment in the transverse colon, 6 (27%) in the ascending colon, 2 (9%) in the caecum and 5 (23%) had multiple skip segments. In both rectosigmoid Hirschsprung's disease cases, the skip segment was in the sigmoid colon. Overall, the length of the skip segment was variable, with the entire transverse colon ganglionated in some cases.
  
  
  CONCLUSIONS
  SSHD occurs predominantly in patients with TCA. The existence of a skip area of normally innervated colon in TCA may influence surgical management, enabling surgeons to preserve and use the ganglionated skip area during pull-through operations.
authors: National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Dublin 12, Ireland.
authors: Anne-Marie
authors: AM
authors: O'Donnell
authors: Prem
authors: P
authors: Puri
mesh_terms: D003106:Colon / Q000294:innervation*; D017615:Enteric Nervous System / Q000473:pathology*; D005260:Female; D006627:Hirschsprung Disease / Q000196:embryology / Q000473:pathology*; D006801:Humans; D008297:Male