Understanding the surgical pitfalls in total mesorectal excision: Investigating the histology of the perirectal fascia and the pelvic autonomic nerves

Abstract

AimExcellent understanding of the arrangement of fasciae and nerves surrounding the rectum is necessary for total mesorectal excision (TME). However, the fasciae anterolateral to the mesorectum and surrounding the low-rectum are still poorly understood. We studied the perirectal fascia along the complete length of the rectum in en-bloc cadaveric specimens and the University Medical Center Utrecht (UMCU) pelvic dataset, and describe implications for TME. MethodsFour 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 m 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. ResultsMultiple fascial layers surrounded the upper rectum. In the 'holy plane' of TME, laminae merged with the mesorectal and parietal fascia. Nerves ran directly laterally to the mesorectal fascia. More caudally, the mesorectal fascia approached the longitudinal layer of the rectal muscularis propria with the neurovascular bundles situated anterolaterally. The mesorectal fascia had a variable appearance in terms of thickness and completeness, which was most prominent anterolaterally. Conclusion 3Optimal TME requires dissection on the mesorectal fascia to preserve the nerves. Rectal surgeons are challenged in doing so as the mesorectal fascia varies in thickness and is often absent in some areas. More caudally, a wider excision may be needed to avoid incomplete specimens.4

Using fluorescence lymphangiography to define the ileocolic mesentery: proof of concept for the watershed area using real-time imaging

“…This demarcation can be used to determine the appropriate mesenteric lymphadenectomy. There are clinical implications for using these boundaries to guide optimal oncological resection, similar to the concept of the "holy plane" for TME (3,4,16).…”

Anatomy of the female pelvic nerves: a macroscopic study of the hypogastric plexus and their relations and variations

“…As described, the 'Holy Plane' is a well-known cleavage region between the neurovascular structures of the pelvis and the innermost layers of the fascia surrounding the rectum, known as visceral mesorectal fascia, and the anterior leaf of the parietal mesorectal fascia (Heald, 1988;Balta et al, 2015). It has been used for more than 30 years as the dissection plane with low risk of autonomic nerve damage during total mesorectal excision (Faucheron, 2005;Balta et al, 2015;Kraima et al, 2015). While dissecting the 'Holy Plane', the surgeon must pass anterior to the SHP, medial to the left and right hypogastric nerves.…”

“…For instance, after nerve-sparing rectal cancer resection, micturition disorders in 25% and sexual dysfunction in 18-28% of the patients were noted (Abdelli et al, 2017). Different intervention sites in the lesser pelvis were explored, such as the perirectal fascia, but the dataset with regard to the autonomic nerve supply is still contradictory, even for the specific nerve-deprived layer between the superior hypogastric plexus and the mesorectum, termed the 'Holy Plane' (Heald, 1988;Kraima et al, 2015). While the autonomic innervation as a potential cause of these dysfunctions has been thoroughly investigated for males (Beveridge et al, 2015), very limited data exist today with regard to the autonomic plexuses of the female pelvis (e.g.…”

Internal anal sphincter nerves – a macroanatomical and microscopic description of the extrinsic autonomic nerve supply of the internal anal sphincter

“…The latter part corresponds in its anterolateral portion to the pubococcygeal muscle which merges with the longitudinal muscle layer of the rectum to form the conjoint longitudinal muscle. Whereas the mesorectal fascia and the parietal pelvic fascia are distinguishable at higher levels of the small pelvis, they become incomplete and condensed at the anorectal junction and eventually merge towards the conjoint longitudinal muscle and the perineal body . Thus, preservation of the IAS nerves is a challenging task due to absence of clearly identifiable planes and easy‐to‐open interfaces.…”