Anatomy of the perirectal fascia at the level of rectosacral fascia revisited

Background:The relative anatomical understanding of the perirectal fasciae is of paramount importance for the proper performance of total mesorectal excision(TME).This study was to demonstrate the planes of TME and validates the intraoperative findings using cadaveric observations.Methods:In this combined retrospective and prospective study,bilateral attachment of the rectosacral fascia(RSF)was observed in 28 cadaveric specimens(male,n=14;female,n=14).From January 2018 to December 2019,surgical videos of 67 patients who underwent laparoscopic TME at the Affiliated Union Hospital of Fujian Medical University(Fuzhou,China)were reviewed and interpreted with the cadaveric findings.Results:The RSF(synonym:Waldeyer’s fascia)is the end of the pre-hypogastric fascia at the level of S4 and comprises two layers(upper and lower).These two layers provide double fascial protection for the venous sacral plexus.It inserts into the fascia propria of the rectum along a broad horizontal arc that merges anterolaterally in an oblique downward direction until it meets the posterolateral merge of Denonvilliers’fascia at the lateral rectal ligament(LRL).This ligament does not look like a true ligament but is more likely to be a fascial combination that cushions the rectal innervation and middle rectal vessels.Conclusions:Understanding the lateral attachment of RSF and its contribution to LRL provides invaluable surgical guidance to dissect this critical area.Therefore,lateral dissection is proposed from the anterior to the posterior direction to find the correct plane that guarantees an intact mesorectal envelope to protect the important nearby nerve structures.

Morphology of the anterior mesorectum:a new predictor for local recurrence in patients with rectal cancer

Background:Pre-operative assessment with high-resolution magnetic resonance imaging(MRI)is useful for assessing the risk of local recurrence(LR)and survival in rectal cancer.However,few studies have explored the clinical importance of the morphology of the anterior mesorectum,especially in patients with anterior cancer.Hence,the study aimed to investigate the impact of the morphology of the anterior mesorectum on LR in patients with primary rectal cancer.Methods:A retrospective study was performed on 176 patients who underwent neoadjuvant treatment and curative-intent surgery.Patients were divided into two groups according to the morphology of the anterior mesorectum on sagittal MRI:(1)linear type:the anterior mesorectum was thin and linear;and(2)triangular type:the anterior mesorectum was thick and had a unique triangular shape.Clinicopathological and LR data were compared between patients with linear type anterior mesorectal morphology and patients with triangular type anterior mesorectal morphology.Results:Morphometric analysis showed that 90(51.1%)patients had linear type anterior mesorectal morphology,while 86(48.9%)had triangular type anterior mesorectal morphology.Compared to triangular type anterior mesorectal morphology,linear type anterior mesorectal morphology was more common in females and was associated with a higher risk of circumferential resection margin involvement measured by MRI(35.6%[32/90]vs.16.3%[14/86],P=0.004)and a higher 5-year LR rate(12.2%vs.3.5%,P=0.030).In addition,the combination of linear type anterior mesorectal morphology and anterior tumors was confirmed as an independent risk factor for LR(odds ratio=4.283,P=0.014).Conclusions:The classification established in this study was a simple way to describe morphological characteristics of the anterior mesorectum.The combination of linear type anterior mesorectal morphology and anterior tumors was an independent risk factor for LR and may act as a tool to assist with LR risk stratification and treatment selection.

Chylous ascites has a higher incidence after robotic surgery and is associated with poor recurrence-free survival after rectal cancer surgery

Background:Postoperative chylous ascites is an infrequent condition after colorectal surgery and is easily treatable.However,its effect on the long-term oncological prognosis is not well established.This study aimed to investigate the short-term and long-term impact of chylous ascites treated with neoadjuvant therapy followed by rectal cancer surgery and to evaluate the incidence of chylous ascites after different surgical approaches.Methods:A total of 898 locally advanced rectal cancer patients treated with neoadjuvant chemoradiotherapy followed by surgery between January 2010 and December 2018 were included.The clinicopathological data and outcomes of the patients with chylous ascites were compared with those of the patients without chylous ascites.The primary endpoint was recurrence-free survival(RFS).To balance baseline confounders between groups,propensity score matching(PSM)was performed for each patient with a logistic regression model.Results:Chylous ascites was detected in 3.8%(34/898)of the patients.The incidence of chylous ascites was highest after robotic surgery(6.9%,6/86),followed by laparoscopic surgery(4.2%,26/618)and open surgery(1.0%,2/192,P=0.021).The patients with chylous ascites had a significantly higher number of lymph nodes harvested(15.6 vs.12.8,P=0.009)and a 3-day longer postoperative hospital stay(P=0.017).The 5-year RFS rate was 64.5%in the chylous ascites group,which was significantly lower than the rate in the no chylous ascites group(79.9%;P=0.007).The results remained unchanged after PSM was performed.The chylous ascites group showed a nonsignificant trend towards a higher peritoneal metastasis risk(5.9%vs.1.6%,P=0.120).Univariate analysis and multivariate analysis confirmed chylous ascites(hazard ratio=3.038,P<0.001)as an independent negative prognostic factor for RFS.Conclusions:Considering the higher incidence of chylous ascites after laparoscopic and robotic surgery and its adverse prognosis,we recommend sufficient coagulation of the lymphatic tissue near the vessel origins,especially during minimally invasive surgery.