Identification of the fascia propria by magnetic resonance imaging and its relevance to preoperative assessment of rectal cancer

PURPOSE: If rectal cancer does not penetrate the fascia propria of the rectum and the rectum is removed with the fascial envelope intact (extrafascial excision), then local recurrence of the cancer will be minimal. Modern imaging techniques have identified a fascial plane surrounding the rectum and mesorectum, and it has been suggested that this is the fascia propria. The aim of this study was to identify whether this plane is the rectal fascia propria and whether tumor invasion through this fascia can be identified preoperatively. METHODS: Two separate experiments were performed: 1) pelvic magnetic resonance imaging was performed before and after dissection and marking of the plane of extrafascial dissection of the rectum of a cadaver; and 2) magnetic resonance imaging was performed in 43 rectal cancer patients preoperatively. Two radiologists independently reported the depth of tumor invasion in relation to the fascia propria. The tumors were resected by extrafascial excision, and a pathologist independently reported the relation of the tumor to the fascia propria. RESULTS: The marker inserted in the extrafascial plane showed that the plane visualized on pelvic magnetic resonance imaging was the fascia propria dissected in extrafascial excision of the rectum. The magnetic resonance imaging detected tumor penetration through the fascia propria with a sensitivity of 67 percent, a specificity of 100 percent, and an accuracy of 95 percent. CONCLUSION: The surgical fascia propria can be identified on preoperative magnetic resonance imaging in patients with rectal cancer. Tumor invasion through this fascia can be detected on magnetic resonance imaging. This method of assessment offers a new way to select those patients who require preoperative radiotherapy.Supported by a research grant from The Maurice and Phyllis Paykel Trust, Parnell, Auckland, New Zealand.     

Definition of total mesorectal excision, including the perineal phase: technical considerations

BACKGROUND: Total mesorectal excision (TME) has contributed to a decline in local recurrence. The operation is difficult because of the complicated anatomy of the pelvis and the narrow spaces in the pelvis. We review the anatomy related to TME and we present our surgical technique. ANATOMY: The pelvis can be divided into a parietal compartment and a visceral compartment. Both compartments are covered by a fascial layer: the parietal and the visceral fascia. A space between these fascial layers can be opened by dividing loose areolar tissue. The pelvic autonomic nerves consist of the sympathetic hypogastric nerve and the parasympathetic sacral splanchnic nerve. At the pelvic sidewall these nerves join in the inferior hypogastric plexus. SURGERY: We present our surgical technique based on careful dissection under direct vision and describe our approach to abdominoperineal resection in the knee-chest position. This position enables en bloc resection of the levator ani muscle with the mesorectum, preventing positive circumferential margins in distal rectal tumor. CONCLUSION: TME is a difficult and challenging operation. Continuous attention to surgical technique and anatomy is important to keep up the high standards of contemporary rectal surgery.     

Operating Behind Denonvilliers’ Fascia for Reliable Preservation of Urogenital Autonomic Nerves in Total Mesorectal Excision: A Histologic Study Using Cadaveric Specimens, Including a Surgical Experiment Using Fresh Cadaveric Models

Purpose Little is known about which urogenital nerves are liable to be injured along surgical planes in front of or behind Denonvilliers’ fascia. Methods and Results Using semiserial histology for five fixed male pelves, we demonstrated that: 1) left/right communicating branches of bilateral pelvic plexuses run immediately in front of Denonvilliers’ fascia; and 2) a lateral continuation of Denonvilliers’ fascia separates the urogenital neurovascular bundle from the mesorectum. Notably, the mesorectum contains no or few extramural ganglion cells. At the level of the seminal vesicles, incision in front of Denonvilliers’ fascia seems likely to injure superior parts of the pelvic plexus and the left/right communication. Moreover, at the prostate level, this incision misleads the surgical plane into the neurovascular bundle. Fresh cadaveric dissections of five unfixed male pelves confirmed that the surgical plane in front of Denonvilliers’ fascia continues to a fascial space for the pelvic plexus containing ganglion cell clusters lateral and/or inferior to the seminal vesicles. Conclusions To preserve all autonomic nerves for urogenital function, optimal total mesorectal excision for rectal cancer requires dissection behind Denonvilliers’ fascia.     

The surgical anatomy of the rectum — a review with particular relevance to the hazards of rectal mobilisation

The major complications of rectal surgery that are wholly or partially avoidable by the use of an anatomically based dissection are haemorrhage from presacral veins, perforation of the rectum, damage to pelvic autonomic nerves and inadequate clearance of a rectal cancer. Important technical points in minimising the incidence of these complications are: (1) posterior dissection in the presacral space; (2) entry to this space by sharp dissection immediately posterior to the superior rectal artery; (3) deliberate incision of the rectosacral fascia; (4) anterior dissection posterior to Denonvilliers fascia in benign disease; (5) removal of the entire mesorectum for low rectal cancer. Other anatomical points not widely appreciated are: 1. The middle rectal artery does not run in the lateral ligaments of the rectum, but below them, on levator ani. It reaches the rectum by penetrating Denonvilliers' fascia. 2. The lateral ligaments may contain an accessory middle rectal artery in 25% of cases. 3. The pelvic autonomic nerves are buried in endopelvic fascia on the pelvic side wall, but come to lie close to the anterior aspect of the rectum at the level of the prostate or upper vagina.     

Total mesorectal excision and preservation of autonomic nerves]

The procedure of total mesorectal excision (TME) becomes a gold standard for the treatment of rectal cancer. The reason is the marvelously low incidence of local recurrence after TME even without other adjuvant treatment, which has been reported by several independent groups. Although controversy still exists about the role of TME in upper rectal cancer, it is now widely accepted for cancers of the middle and lower third. There are number of histopathological evidences that cancer cells can spread distally several centimeters from the lower margin of cancer, and cancer bearing lymph nodes are found in the distal portion of the mesorectal tissues far from the cancer. Therefore, the distal clearance of mesorectum should be performed downwardly to the level of pelvic diaphragm (puborectalis) and the rectum is divided within a few centimeters from the pelvic floor musculature. TME defines an en-bloc procedure, along the plane between parietal and visceral pelvic fasciae. If the dissection plane is breached, the chance of visceral pelvic fascia tearing is raised and mesorectal tissue might reside in the pelvis. There are problems in auditing the procedure. As many surgeons agree, this procedure requires a learning curve. Theoretically, the autonomic nerves run between the visceral and parietal pelvic fasciae since the nerves must be preserved to make visceral fascial envelop. Any patient who become incontinent or impotent after the surgery should have received decorticating surgery other than TME. Thus, the high quality of TME should fulfill two clinical measurements: absence of impotence or incontinence and at least single digit, 5-year, cumulative recurrence rate regardless of adjuvant therapy.     

Denonvilliers筋膜的微创解剖认识及其临床价值

1836年,法国外科学家Charles-Pierre Denonvilliers首次描述在男性的直肠与膀胱、精囊腺和前列腺之间存在薄层致密组织,后被称为Denonvilliers筋膜。1982年英国外科学家R.J. Heald教授提出全直肠系膜切除术（TME）理念,历经数十年的临床实践,TME已成为中低位直肠癌手术的金标准。根据TME理念,直肠后方及侧方均应在盆筋膜壁层内面与直肠固有筋膜间分离,而在直肠前方于Denonvilliers筋膜前方分离、肿瘤下方2 cm处倒U形离断并切除部分Denonvilliers筋膜。然而,资料显示,由于盆腔自主神经（PAN）的损伤,TME术后排尿及性功能障碍发生率居高不下。因此,进一步理清盆腔筋膜和自主神经解剖的认识,对于改善患者术后功能尤为重要。在国内外众多学者研究的基础上,我们从胚胎发育学、解剖学、组织学和外科手术角度对盆腔筋膜及外科层面进行深入探索,指出Denonvilliers筋膜不属于直肠固有筋膜的范畴、如非肿瘤浸润应予保留,并提出保留Denonvilliers筋膜全直肠系膜切除术（iTME）的理念;并采用多中心临床试验加以验证。在此基础上我们联合国内直肠癌外科领域专家,发布iTME中国专家共识,旨在提高从业者对神经功能保护的认识,规范手术操作,造福广大患者。     

The "meso" of the rectum and the "meso" of the pancreas: similar terms but distinct concepts in surgical oncology

A correspondence between the "meso" of the rectum and of the pancreas has recently been reported. Here we highlight the differences between mesorectum and mesopancreas. Based on anatomical findings from a series of 89 consecutive pancreaticoduodenectomies and 71 consecutive total mesorectal excisions, we observed that in contrast to the mesorectum, the mesopancreas did not have well-defined anatomic boundaries and was continuous and connected through its components with the para-aortic area. In rectal cancer,tumor deposits and nodal involvement could be confined to the mesorectum(i.e., within the mesorectal fascia), whereas in pancreatic carcinoma, tumor deposits and nodal metastases occurred in the boundless mesopancreatic area. Total mesorectal excision was made en bloc with the rectum by dissecting along the mesorectal fascia; this was not the case for mesopancreatic excision since anatomical demarcation of the mesopancreas did not exist. Moreover, the growth pattern of pancreatic cancer showed greater dispersion, which was more prominent at the invasive front of the tumor and could potentially affect the status of the resection margin. These findings indicate that the mesorectum and mesopancreas are completely distinct from the pathological, surgical, and oncological standpoints.     

Studies of the vascular anatomy of the mesorectum support the concept of the total mesorectal excision

The relation between the mesorectal vessels and the mesorectal fascia needs to be clarified, as a total mesorectal excision (TME) probably derives its advantage from the fact that the visceral or mesorectal fascia can be regarded as a “tumor-tight packaging” and does not contain anatomically preformed perforations. The purpose of this investigation was to study both rectal arterial supply and vascular distribution pattern within the mesorectum. The arterial supply to the rectum was studied with the injection technique in 12 porcine and 28 human TME specimens. We stain-marked 12 porcine and 15 human specimens. Thirteen human specimens were angiographed after filling their arterial bed with a radio-opaque substance. The superior rectal artery is the main rectal artery. Terminal branches extend downwards and forward around the rectum to the level of the levator and muscle. The superior rectal artery and vein were found to be enclosed in a fibrous sheath. The main mesorectal vessels do not penetrate the mesorectal fascia. This study supports the hypothesis of bilateral somatic and one central visceral compartment in the pelvis and implies the absolute necessity of tumor removal within an intact mesorectal fascia. Received: 15 August 2000 / Accepted in revised form: 1 October 2000     

Vascular organization in the mesorectum: angiography of rectal resection specimens

The technical advances in rectal cancer surgery are known as the total mesorectal excision. The resection in an anatomically defined plane under direct vision and with sharp dissection distinguishes it conventional rectal surgery. The result must be a complete mesorectum without deep gouges. We performed specimen angiography to confirm completeness of the removed mesorectum. Thirteen total mesorectal excision specimens were examined by angiography after continence-preserving resection of rectal carcinoma. In 11 of the 13 cases the vascular supply was exclusively via the superior rectal artery. In two cases with hypoplastic left terminating branches of the superior rectal artery there was additional perfusion via a caudally ascending vessel or via smaller vessels connected laterally. In all specimens both arterial supply and venous outflow were located within the mesorectal fascial sheath. There was no radio-opaque substance leaking from the mesorectal surface in the case of a complete mesorectal specimen. Tiny vascular branches running laterally occurred in 7 of the 13 cases. We found no larger vascular connections branching off in the lateral direction. The rectal blood supply comes almost exclusively through the superior rectal vessels. Thus the fascia covering the mesorectum forms, as far as rectal vascularization is concerned, a closed compartment. The mesorectal vessels are enclosed in the fibrous avascular mesorectal fascia. They run close above the fascia. In the case of an incomplete mesorectal excision the specimen angiography shows a stain leaking from the mesorectal fascia. Our method can be used to confirm the completeness of the removed mesorectum.     

Laparoscopic-assisted low anterior resection of the rectum��a review of the fascial composition in the pelvic space

Introduction

Outcomes of rectal cancer treatment depend on the operative technique, and complication rates vary. Complications can occur during mobilization of the rectum, with damage to the ureter, autonomic nerves, and the rectum itself. Frequencies of these complications can be reduced by careful dissection of the correct tissue plane in the pelvic space.

Methodology

This paper reviews the fascial composition of the rectum for low anterior resection of the rectum. To date, fascial composition of the pelvic space has been considered based on clinical anatomy and histological examination of cadaveric specimens. However, clarification of fascial composition is clearly limited, to a certain extent, in histological examinations compared with clinical anatomy.

Conclusions

First, some degree of dissociation must exist between the histological examination and clinical anatomy. Second, surgeons should not consider fascia encountered intraoperatively as an artifact. To address these difficult issues, consideration should be made purely from the perspective of clinical anatomy. Originally, the trunk was embryologically regarded as a multi-layered structure (like an onion). Understanding the fascial composition of the abdomen is comparatively easy when approached from this perspective. If this theory is adapted to the pelvic space in order to avoid antilogy, an understanding of the fascial composition of the pelvic space should also be possible. We review previous papers based on this theory.     

Mesorectal Lymph Nodes: Their Location and Distribution Within the Mesorectum

PURPOSE: Total mesorectal excision is an alternative surgical approach for resectable rectal cancer and is associated with favorable results and a low rate of local recurrence. Despite the popularity of this technique, few data exist regarding the location and distribution of lymph nodes within the rectal mesentery. The purpose of this study was to define the distribution, size, and location of lymph nodes within the mesorectum and on the pelvic side wall. METHODS: Seven fresh cadavers at our institution's Fresh Tissue Dissection Laboratory were studied. The rectum, its mesentery, and all fatty tissue from both pelvic side walls were removed and placed in a lymph node clearing solution for 24 hours. After appropriate dissection, the distribution, size, and location of lymph nodes within the rectal mesentery and pelvic side wall tissue were documented. RESULTS: A total of 174 lymph nodes were identified (approximately 25 per patient). The majority (>80 percent) of lymph nodes were smaller than 3 mm in diameter. Fifty-six percent of the nodes within the rectal mesentery were located in the posterior mesentery, and most were located in the upper two-thirds of the posterior rectal mesentery. CONCLUSIONS: The majority of perirectal lymph nodes are small. There are few lymph nodes within the mesentery of the lower third of the rectum and relatively few in the right and left lateral portions of the mesorectum. We confirm that the majority of nodes are located in the proximal two-thirds of the posterior rectal mesentery. It is possible that removal of these nodes is responsible for the superior oncologic results found with total mesorectal excision in contrast to more traditional surgical techniques.     

Laparoscopic lateral lymph node dissection in two fascial spaces for locally advanced lower rectal cancer

BACKGROUNDThe procedure for lateral lymph node (LLN) dissection (LLND) is complicated and can result in complications. We developed a technique for laparoscopic LLND based on two fascial spaces to simplify the procedure.AIMTo clarify the anatomical basis of laparoscopic LLND in two fascial spaces and to evaluate its efficacy and safety in treating locally advanced low rectal cancer (LALRC).METHODSCadaveric dissection was performed on 24 pelvises, and the fascial composition related to LLND was observed and described. Three dimensional-laparoscopic total mesorectal excision with LLND was performed in 20 patients with LALRC, and their clinical data were analyzed.RESULTSThe cadaver study showed that the fascia propria of the rectum, urogenital fascia, vesicohypogastric fascia and parietal fascia lie side by side in a medial-lateral direction constituting the dissection plane for curative rectal cancer surgery, and the last three fasciae formed two spaces (Latzko''s pararectal space and paravesical space) which were the surgical area for LLND. Laparoscopic LLND in two fascial spaces was performed successfully in all 20 patients. The median operating time, blood loss and postoperative hospitalization were 178 (152-243) min, 55 (25-150) mL and 10 (7-20) d, respectively. The median number of harvested LLNs was 8.6 (6-12), and pathologically positive LLN metastasis was confirmed in 7 (35.0%) cases. Postoperative complications included lower limb pain in 1 case and lymph leakage in 1 case.CONCLUSIONOur preliminary surgical experience suggests that laparoscopic LLND based on fascial spaces is a feasible, effective and safe procedure for treating LALRC.     

Denonvilliers’ Fascia Lies Anterior to the Fascia Propria and Rectal Dissection Plane in Total Mesorectal Excision

PURPOSE Opinion is divided whether Denonvilliers fascia lies anterior or posterior to the anatomic fascia propria plane of anterior rectal dissection in total mesorectal excision. This study was designed to evaluate this anatomic relationship by assessing the presence or absence of Denonvilliers fascia on the anterior surface of the extraperitoneal rectum in specimens resected for both nonanterior and anterior rectal cancer in males.METHODS Surgical specimens were collected prospectively from males undergoing total mesorectal excision for mid and low rectal cancer, with a deep dissection of the anterior extraperitoneal rectum to the pelvic floor. Specimens were histopathologically analyzed using best practice methods for rectal cancer. The anterior aspects of the extraperitoneal rectal sections were examined microscopically for the presence or absence of Denonvilliers fascia.RESULTS Thirty rectal specimens were examined. Denonvilliers fascia was present in 12 (40 percent) and absent in 18 specimens (60 percent). Denonvilliers fascia was significantly more frequently present when tumor involved (55 percent) rather than spared the anterior rectal quadrant (10 percent; difference between groups 45 percent; 95 percent confidence interval, 30–60 percent; P = 0.024, Fishers exact test).CONCLUSIONS When tumors were nonanterior, rectal dissection was conducted on fascia propria in the usual anatomic plane, and Denonvilliers fascia was not present on the specimen. It was almost exclusively found in anterior tumors, deliberately taken by a radical extra-anatomic anterior dissection in the extramesorectal dissection plane. Denonvilliers fascia lies anterior to the anatomic fascia propria plane of anterior rectal dissection and is more closely applied to the prostate than the rectum.Presented at the meeting of the Association of Coloproctology of Great Britain and Ireland, Brighton, United Kingdom, July 10 to 12, 2000.Reprints are not available.     

Laparoscopic low anterior resection with total mesorectal excision for rectal cancer

Rectal resections are the only treatment with curative intent currently accepted world wide. When performed in elective circumstances, laparoscopic rectal excision is technically feasible in surgical approach of mid-rectal cancer in a considerable number of patients. There are many benefits of the laparoscopic approach to rectal resection such as short hospitalization, less pain, less postoperative complications and improved quality of life. However, one mandatory condition in laparoscopic resection of rectum includes complete excision of the rectum and mesorectum, generally ensuring a minimal distal margin of 2cm and circumferential radial clearance before performing a coloanal anastomosis. Here, we present a laparoscopic approach for rectal cancer treatment consisting in a wide resection of the rectum, including the entire fascia with the enclosed mesentery of the rectum.     

Laparoscopic mesorectal excision with preservation of the pelvic autonomic nerves for rectal cancer

BACKGROUND/AIMS: Laparoscopic mesorectal excision with preservation of the autonomic pelvic nerves for rectal cancer including selected advanced lower rectal cancer is now challenging. The aims of the study were to assess the surgical results and short-term outcomes of this procedure prospectively. METHODOLOGY: Seventy-four of 281 rectal cancer patients, since the introduction of laparoscopic colorectal surgery in our hospital, have undergone laparoscopic rectal surgery. The location of the tumor distributed in upper rectum; 33, middle; 22, and lower 19. The mesorectal excision with preservation of the autonomic pelvic nerves was performed for all the patients. The laparoscopic mesorectal excision was performed under 8 to 10 cmH2O CO2 pneumoperitoneum and lymph node dissection was performed along the feeding artery depend on individuals. Ipsilateral lateral lymph node dissection was added for 5 cases of advanced lower rectal cancer. RESULTS: Open conversion occurred in 4 cases, 2 of those were due to locally advanced tumors and 2 technical difficulties in transaction of the distal rectum. There were 15 postoperative complications, 7 anastomotic leakage (10.6%), 3 transient urinary retention (4.1%), 4 wound infection (5.3%), and 1 small bowel obstruction (1.4%). No mortality was recorded in this series. Time of operation was 203 +/- 54 min in mesorectal excision cases and 270 +/- 42 min mesorectal excision with lateral lymph node dissection cases. Blood loss was 92 +/- 90g and 276 +/- 66 g respectively. The hospital length-of-stay was 11.7 days in average. CONCLUSIONS: Laparoscopic mesorectal excision with preservation of autonomic pelvic nerves for rectal cancer patients including selected advanced lower rectal cancer is favorable.     

Discontinuous Rectal Cancer Spread in the Mesorectum and the Optimal Distal Clearance Margin in Situ

PURPOSE: We examined the frequency, mode, and extent of discontinuous spread of rectal cancer in the mesorectum to determine the optimal distal clearance margin in situ. METHODS: Forty consecutive patients with rectal cancer undergoing locally curative resection were studied prospectively. Discontinuous cancer spread in the mesorectum and the extent of distal spread was examined microscopically. A tissue shrinkage ratio comparing the distal clearance margin measured before transection to that measured after fixation in each case, was used to convert microscopically measured extent of distal spread to extent in situ. RESULTS: Discontinuous cancer spread in the mesorectum was observed in 17 cases (43 percent); lymph node metastasis in 15 cases (38 percent) and small deposits other than nodal metastases in 8 cases (20 percent). Distal cancer spread (either intramural or mesorectal) was observed in 6 cases (15 percent). The mean distal clearance margin before transection and after fixation was 3.2 cm and 2 cm, respectively. The mean tissue shrinkage ratio was 60 percent. The maximum extent of microscopic distal spread and adjusted distal spread in situ were 20 and 24 mm, respectively. CONCLUSIONS: Excising the mesorectum with fascia propria circumferentially intact is essential for rectal surgery. The optimal distal clearance margin for the rectal wall as well as the mesorectum in situ can be reduced to 3 cm with a right angle.