title: Understanding the surgical pitfalls in total mesorectal excision: Investigating the histology of the perirectal fascia and the pelvic autonomic nerves.
abstract: OBJECTIVE
  Excellent understanding of fasciae and nerves surrounding the rectum is necessary for total mesorectal excision (TME). However, fasciae anterolateral to the rectum and surrounding the low rectum are still poorly understood. We studied the perirectal fascia enfolding the extraperitoneally located part of the rectum in en-bloc cadaveric specimens and the University Medical Center Utrecht (UMCU) pelvic dataset, and describe implications for TME.
  
  
  METHODS
  Four donated human adult cadaveric specimens (two males, two females) were obtained through the Leeds GIFT Research Tissue Programme. Paraffin-embedded blocks were produced and serially sectioned at 50 and 250 μm intervals. Whole mount sections were stained with haematoxylin & eosin, Masson's trichrome and Millers' elastin. Additionally, the UMCU pelvic dataset including digitalised cryosections of a female pelvis in three axes was studied.
  
  
  RESULTS
  The mid and lower rectum were surrounded by a multi-layered perirectal fascia, of which the mesorectal fascia (MRF) and parietal fascia bordered the 'holy plane'. There was no extra constant fascia forming a potential surgical plane. Nerves ran laterally to the MRF. More caudally, the mesorectal fat strongly reduced and the MRF approached the rectal muscularis propria. The MRF had a variable appearance in terms of thickness and completeness, most prominently at the anterolateral lower rectum.
  
  
  CONCLUSIONS
  Dissection onto the MRF allows nerve preservation in TME. Rectal surgeons are challenged in doing so as the MRF varies in thickness and shows gaps, most prominently at the anterolateral lower rectum. At this site, the risk of entering the mesorectum is great and may result in an incomplete specimen.
authors.affiliation: Department of Anatomy & Embryology, Leiden University Medical Center, Leiden, The Netherlands; Pathology and Tumour Biology, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK.
authors.forename: A C
authors.initials: AC
authors.lastname: Kraima
authors.affiliation: Pathology and Tumour Biology, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK.
authors.forename: N P
authors.initials: NP
authors.lastname: West
authors.affiliation: Pathology and Tumour Biology, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK.
authors.forename: D
authors.initials: D
authors.lastname: Treanor
authors.affiliation: Pathology and Tumour Biology, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK.
authors.forename: D R
authors.initials: DR
authors.lastname: Magee
authors.affiliation: Department of Anatomy, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: R L A W
authors.initials: RL
authors.lastname: Bleys
authors.affiliation: Department of Surgery, Catharina Hospital Eindhoven, Eindhoven, The Netherlands; GROW School of Oncology and Developmental Biology, University of Maastricht, Maastricht, The Netherlands.
authors.forename: H J T
authors.initials: HJ
authors.lastname: Rutten
authors.affiliation: Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: C J H
authors.initials: CJ
authors.lastname: van de Velde
authors.affiliation: Pathology and Tumour Biology, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK.
authors.forename: P
authors.initials: P
authors.lastname: Quirke
authors.affiliation: Department of Anatomy & Embryology, Leiden University Medical Center, Leiden, The Netherlands. Electronic address: m.c.de_ruiter@lumc.nl.
authors.forename: M C
authors.initials: MC
authors.lastname: DeRuiter
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017776:Autonomic Pathways / Q000473:pathology*; D002102:Cadaver; D003082:Colectomy / Q000379:methods*; D005205:Fascia / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010388:Pelvis / Q000294:innervation*; D012004:Rectal Neoplasms / Q000473:pathology / Q000601:surgery*
keywords: Autonomic nerves; Mesorectal fascia; Perirectal fascia; Rectal cancer; Total mesorectal excision