Biomechanical origin of the Denonvilliers’ fascia

Gynecological technical notes for appropriate spacer injections

BACKGROUND

Despite its efficacy, if adherence to dose constraints for surrounding normal tissues proves unattainable, the risk of late radiation-related adverse events after primary radiotherapy involving brachytherapy remains a noteworthy concern. Some studies suggest that similar to prostate radiotherapy, spacers may potentially reduce doses to surrounding healthy rectal or bladder tissues. However, guidance on spacer injections for gynecologic brachytherapy is scarce, and the optimal anatomical location for spacer placement remains undefined. We discuss maximizing the effects of spacers from an anatomical perspective.

FINDINGS

As vesicovaginal and rectovaginal septa form part of the endopelvic fascia and are not uniform tissues, spacer injection resistance varies. In pelvic organ prolapse surgery, saline is injected into the anterior and posterior vaginal walls as a spacer, and the vagina, vesicovaginal septum, and bladder can be fluidly dissected. Relatively firm vesicovaginal septum tissue is used as a reconstructive organ, whereas rectovaginal septum tissue is less dense. Cervical cancer is invasive, involving surrounding fascia and ligaments. Ideally, the vesicovaginal and rectovaginal septa should be resected in radical hysterectomy. Here, spacer adaptation and the technical details of injection are described. When using ultrasound guidance for spacer injection, the target site should be adequately magnified, and the spacer ideally injected into the incision layer during radical hysterectomy. Finally, posthysterectomy, the intestinal tract may adhere to the vaginal cuffs. Therefore, artificial ascites may be useful; however, the spread depends on perioperative manipulation.

CONCLUSIONS

Anatomical and surgical viewpoints are advantageous for safe, therapeutic, and replicable spacer injection administration.

From basic to clinical: Anatomy of Denonvilliers' fascia and its application in laparoscopic radical resection of rectal cancer

The total mesorectal excision (TME) approach has been established as the gold standard for the surgical treatment of middle and lower rectal cancer. This approach is widely accepted to minimize the risk of local recurrence and increase the long-term survival rate of patients undergoing surgery. However, standardized TME causes urogenital dysfunction in more than half of patients, thus lowering the quality of life of patients. Of note, pelvic autonomic nerve damage during TME is the most pivotal cause of postoperative urogenital dysfunction. The anatomy of the Denonvilliers' fascia (DVF) and its application in surgery have been investigated both nationally and internationally. Nevertheless, controversy exists regarding the basic to clinical anatomy of DVF and its application in surgery. Currently, it is a hotspot of concern and research to improve the postoperative quality of life of patients with rectal cancer through the protection of their urinary and reproductive functions after radical resection. Herein, this study systematically describes the anatomy of DVF and its application in surgery, thus providing a reference for the selection of surgical treatment modalities and the enhancement of postoperative quality of life in patients with middle and low rectal cancer.

Where is the optimal plane to mobilize the anterior rectal wall in female patients undergoing total mesorectal excision?

BACKGROUND

Since Heald proposed the total mesorectal excision (TME) procedure, the prognosis of patients with rectal cancer has been significantly improved. But Heald did not specifically describe the anterior surgical plane in female patients. And the surgical plane for mobilizing the anterior rectal wall during TME surgery in female patients remains controversial.

AIM

To investigate the anatomy of the female pelvis and identify the optimal plane for mobilizing the anterior rectal wall.

METHODS

We retrospectively collected surgical procedure videos and clinical data of female patients diagnosed with middle or low rectal cancer who underwent the TME procedure between January 2020 and October 2022 across six hospitals. The patients were divided into two groups based on the surgical approach used to mobilize the anterior rectal wall: The experimental group was to open the peritoneum at the lowest point of the peritonea reflection and enter the plane for mobilizing, while the control group was cut at 0.5-1 cm above the peritoneal reflection and enter another plan. Then, we compared the preoperative and postoperative information between the two groups. We also dissected and observed ten adult female pelvises to analyze the anatomic structure and compare the entry plane between the two approaches. Finally, we researched the pathological structure between the rectum and the vagina.

RESULTS

Finally, 77 cases that met the criteria were included in our study. Our observations revealed that the experimental group underwent a smooth procedure, entering the plane amidst the mesorectal fascia and adventitia of the vagina, whereas the control group entered the plane between the vaginal adventitia and muscle layers. Compared to the control group, the experimental group showed a significant decrease in intraoperative bleeding [22.5 (19.5-50) mL vs 17 (5-20) mL, P = 0.01], as well as a shorter duration of hospitalization [9 (7-11.25) d vs 7 (6-10) d, P = 0.03]. Through the examination of surgical videos and cadaveric studies, we discovered that Denonvilliers' fascia is absent in females. Additionally, pathological sections further revealed the absence of Denonvilliers' fascia in females, with only loose connective tissue present between the mesorectal fascia and adventitia of the vagina.

CONCLUSION

The plane amidst the mesorectal fascia and vaginal adventitia is the optimal surgical plane to mobilize the anterior rectal wall for female patients undergoing the TME procedure.

The "Y"-shaped Denonvilliers' fascia and its adjacent relationship with the urogenital fascia based on a male cadaveric anatomical study

BACKGROUND

Controversies regarding the anatomical structure of Denonvilliers' fascia and its relationship with surrounding fasciae have sparked a heated discussion, especially concerning whether Denonvilliers' fascia is multilayered. This study aimed to expound on the anatomical structure of Denonvilliers' fascia and its correlation with the peritoneum from the sagittal view and clarify the complex fascial relationship.

METHODS

Our study was performed on 20 adult male pelvic specimens fixed in formalin, including 2 entire pelvic specimens and 18 semipelvic specimens. The local adjacent organs and fasciae were dissected, and Denonvilliers' fascia was observed and removed for histological examination.

RESULTS

Denonvilliers' fascia was typically single-layered and tough. On the sagittal plane, the peritoneum constituting the peritoneal reflection and Denonvilliers' fascia formed a "Y" shape. Denonvilliers' fascia originated from the peritoneal reflection, extended along the ventral side of the seminal vesicles and prostate, continuing caudally; its bilateral sides closely connected to the urogenital fascia (UGF) of the pelvic wall. In addition, histology preliminarily indicated that the basal cell layers of the peritoneum and Denonvilliers' fascia were continuous and formed a "Y" shape. Furthermore, the basal cells of the two peritonea extended to Denonvilliers' fascia, creating a fused double-layered structure. Some tiny blood vessels or a network of such vessels extended from the peritoneum to Denonvilliers' fascia.

CONCLUSION

Denonvilliers' fascia, the extension of the peritoneum in the pelvic floor, appears as a single-layered "Y"-shape on the sagittal plane. Our study provides new support for the peritoneal fusion theory. Understanding the anatomical characteristics of Denonvilliers' fascia and its relationship with the UGF is of guiding significance for inexperienced colorectal surgeons to conduct rectal cancer surgery.

Positional relationship between the lateral border of Denonvilliers' fascia and pelvic plexus

Denonvilliers' fascia is an important landmark of the dissection layer during prostate or rectal surgeries. However, there are few reports on its lateral extension. This anatomical study aimed to define the lateral border of Denonvilliers' fascia and use it as an anatomical landmark to identify the origin and distribution of the nerve branches of the pelvic plexus. We investigated the lateral extent and position of the lateral border of Denonvilliers' fascia through macroscopic examination of 12 pelvic halves from eight cadavers and histological examination of two cadavers. The Denonvilliers' fascia extended laterally to be attached to the pelvic plexus on the lateral border. The origins of nerve branches from the pelvic plexus to the pelvic organs, except the rectum, were located anterior or anterosuperior to the lateral border of Denonvilliers' fascia. The origins of nerve branches to the prostate were mainly anterior to the lateral border of Denonvilliers' fascia; however, in 3/12 pelvic halves, the nerve branches originated in the region posteroinferior to the lateral border of Denonvilliers' fascia. The attachment point of Denonvilliers' fascia to the prostate was more superior in these three pelvic halves (distance from the top point of the posterior surface of the prostate to the attachment point, 5.6 ± 1.9 mm) than that in the other nine pelvic halves (10.1 ± 3.6 mm). The lateral border of Denonvilliers' fascia is closely related to the pelvic plexus, suggesting its usefulness as an anatomical landmark to identify the origin of nerve branches from the pelvic plexus.

Review of Denonvilliers' fascia: the controversies and consensuses

The Denonvilliers' fascia (DVF) plays an important role in rectal surgery because of its anatomic position and its relationship to the surrounding organs. It affects the surgical plane anterior to the rectum in the procedure of total mesorectal excision (TME). Anatomical and embryological studies have helped us to understand this structure to some extent, but many controversies remain. In terms of its embryonical origin, there are three mainstream hypotheses: peritoneal fusion of the embryonic cul-de-sac, condensation of embryonic mesenchyme, and mechanical pressure. Regarding its architecture, the DVF may be a single, two, or multiple layers, or a composite single-layer structure. In women, most authors deem that this structure does exist but they are willing to call it the rectovaginal septum rather than the DVF. Operating behind the DVF is supported by most surgeons. This article will review those mainstream studies and opinions on the DVF and combine them with what we have observed during surgery to discuss those controversies and consensuses mentioned above. We hope this review may help young colorectal surgeons to have a better understanding of the DVF and provide a platform from which to guide future scientific research.

The 'multilayer' theory of Denonvilliers' fascia: anatomical dissection of cadavers with the aim to improve neurovascular bundle preservation during rectal mobilization

AIM

Denonvilliers' fascia is thought to be a multilayered fascial structure, based on its embryological development with the neurovascular bundle embedded within it. Recently, this theory had been proven histologically and by confocal microscopy in many published articles. However, the literature does not report on how surgeons can identify these structures. We aimed to determine the optimal surgical approach for preserving these critical structures.

METHOD

Eighteen cadavers (13 male/five female) were included and treated according to the ethical considerations stated in the donation consent of our institution. Dissection was performed with the assistance of binocular loupes for better anatomical detail. The compositions of the prerectal fascia and the neurovascular bundle were observed and recorded at different levels of dissection using a high-definition camera.

RESULTS

The theoretical multilayered fascia was found in male specimens as three fascial layers originating from the perineal body, seminal vesicles and posterior bladder neck. The first layer merged posterolaterally and fused with the rectosacral fascia (Waldeyer's fascia). The neurovascular bundle in male specimens was observed piercing the second and third layers, while the first layer acted as a protective cover. Dissection of female specimens demonstrated only one layer in the prerectal space.

CONCLUSION

Intiating anterior rectal mobilization by incising the peritoneum posterior to its reflection seems to be anatomically correct to preserve DVF. However, its applicability may be difficult in a narrow chanllenging pelvis. The lateral rectal ligaments and Waldeyer's fascia should be dissected from their attachments to the proper fascia of the rectum.

Periodic acid-Schiff (PAS) reaction and plastination in whole body slices. A novel technique to identify fascial tissue structures

Since collagen rich fascial tissue is often very delicate and difficult to discern on native tissue slices, we have developed a method for staining full-body slices using the periodic acid-Schiff (PAS) reaction with subsequent plastination. Since the PAS reaction primarily stains carbohydrates, we could exploit the circumstance that different collagen types vary in carbohydrate content. Contrary to fasciae, tissues such as muscle, bone, nerves and blood vessels exhibit significantly less staining or remain unstained. We have validated the whole-body slice staining results in microscopic tissue slides which were stained with standard extracellular matrix stains such as Masson-Goldner trichrome stain and van-Gieson stain. Furthermore, we have performed immunofluorescence imaging to confirm the presence of collagen in the stained tissue. We achieved very good staining and plastination results and were able to clearly identify even very thin fascia in transversal body slices. This technique may prove useful in advancing our knowledge on the complex topography of fascial structures.

Rectal mobilization: the place of Denonvilliers' fascia and inconsistencies in the literature

Confusion remains as to what is meant by Denonvilliers' fascia. This review searched the literature on pelvic surgical anatomy to determine whether there is agreement with Denonvilliers' original description and its implication in defining the correct anterior plane of dissection when mobilizing the rectum. The original French description of the fascia was translated into English and then compared both with French and with English studies identified by searching PubMed, Medline and Scopus from 1836 to June 2015. Special emphasis was given to the years between 1980 and 2015 in order to capture the literature pertinent to, and following on from, the description of total mesorectal excision for rectal cancer. The final literature search revealed 16 studies from the original 2150 citations. Much of the debate was concerned with the origin and development of the fascia, arising from either the 'fusion' or the 'condensation' of local primitive tissue into a mature 'multilayered' structure. Controversy regarding the correct plane of rectal mobilization occurs as a result of different interpretations by surgeons, anatomists and radiologists and bears little resemblance to Denonvilliers' original description. This may reflect wide anatomical variability in the adult pelvis or a form of dissection artefact. Further study is required to investigate this. Logically, for both men and women, the plane of rectal mobilization should be behind Denonvilliers' fascia and between it and the fascia propria of the rectum.

Effect of preservation of Denonvilliers' fascia during laparoscopic resection for mid-low rectal cancer on protection of male urinary and sexual functions

The aim of this study was to investigate the effect of preservation of Denonvilliers' fascia (DF) during laparoscopic resection for mid-low rectal cancer on protection of male urogenital function. Whether preservation of DF during TME is effective for protection of urogenital function is largely elusive.Seventy-four cases of male mid-low rectal cancer were included. Radical laparoscopic proctectomy was performed, containing 38 cases of preservation of DF (P-group) and 36 cases of resection of DF (R-group) intraoperatively. Intraoperative electrical nerve stimulation (INS) on pelvic autonomic nerve was performed and intravesical pressure was measured manometrically. Urinary function was evaluated by residual urine volume (RUV), International Prostatic Symptom Score (IPSS), and quality of life (QoL). Sexual function was evaluated using the International Index of Erectile Function (IIEF) scale and ejaculation function classification.Compared with performing INS on the surfaces of prostate and seminal vesicles in the R-group, INS on DF in the P-group exhibited higher increasing intravesical pressure (7.3 ± 1.5 vs 5.9 ± 2.4 cmH2O, P = 0.008). In addtion, the P-group exhibited lower RUV (34.3 ± 27.2 vs 57.1 ± 50.7 mL, P = 0.020), lower IPSS and QoL scores (7 days: 6.1 ± 2.4 vs 9.5 ± 5.9, P = 0.002 and 2.2 ± 1.1 vs 2.9 ± 1.1, P = 0.005; 1 month: 5.1 ± 2.4 vs 6.6 ± 2.2, P = 0.006 and 1.6 ± 0.7 vs 2.1 ± 0.6, P = 0.003, respectively), higher IIEF score (3 months: 10.7 ± 2.1 vs 8.9 ± 2.0, P = 0.000; 6 months: 14.8 ± 2.2 vs 12.9 ± 2.2, P = 0.001) and lower incidence of ejaculation dysfunction (3 months: 28.9% vs 52.8%, P = 0.037; 6 months: 18.4% vs 44.4%, P = 0.016) postoperatively.Preservation of DF during laparoscopic resection for selective male mid-low rectal cancer is effective for protection of urogenital function.

Concepts of the rectovaginal septum: implications for function and surgery

INTRODUCTION

In the pelvis, the rectogenital septum (RGS) separates the urogenital compartment from the digestive compartment. In men, it corresponds to Denonvilliers' rectoprostatic fascia or rectovesical septum (RVS). Its purpose-and, indeed, its existence-are controversial in women. The purpose of this review was to update knowledge about the RGS in women and, in particular, to clarify its relationship to pelvic nerves in order to deduce practical consequences of pelvic surgery and compare it to the RVS in men.

METHODS

A review of the anatomical and surgical literature was undertaken. Evidence for embryological origin, composition, and surgical importance of the RGS in women and men is suggested.

RESULTS

This manuscript presents evidence of the existence of the RGS in both women (rectovaginal septum, RVaS) and men (rectovesical septum, RVS). It originates from the genital structures and extends from the rectogenital pouch to the perineal body. It is composed of connective tissue associated with bundles of smooth muscle cells and has lateral expansions in close contact with neurovascular bundles originating from the inferior hypogastric plexus. During pelvic surgery for carcinoma, preservation of nerve fibers of erectile bodies is necessary if possible. The RGS is thus an important surgical landmark during urogenital sinus surgery, prolapse surgery, and proctectomy in women as well as during proctectomy and prostatectomy in men.

CONCLUSIONS

The RGS is present in women as well as in men, with great similarities between the two sexes. It represents an important surgical landmark during pelvic nerve-sparing surgery.

Site-dependent and interindividual variations in Denonvilliers' fascia: a histological study using donated elderly male cadavers

Background

Site-dependent and interindividual histological differences in Denonvilliers’ fascia (DF) are not well understood. This study aimed to examine site-dependent and interindividual differences in DF and to determine whether changes in the current approach to radical prostatectomy are warranted in light of these histological findings.

Methods

Twenty-five donated male cadavers (age range, 72–95 years) were examined. These cadavers had been donated to Sapporo Medical University for research and education on human anatomy. Their use for research was approved by the university ethics committee. Horizontal sections (15 cadavers) or sagittal sections (10 cadavers) were prepared at intervals of 2–5 mm for hematoxylin and eosin staining. Elastic–Masson staining and immunohistochemical staining were also performed, using mouse monoclonal anti-human alpha-smooth muscle actin to stain connective tissues and mouse monoclonal anti-human S100 protein to stain nerves.

Results

We observed that DF consisted of disorderly, loose connective tissue and structures resembling “leaves”, which were interlacing and adjacent to each other, actually representing elastic or smooth muscle fibers. Variations in DF were observed in the following: 1) configuration of multiple leaves, including clear, unclear, or fragmented behind the body and tips of the seminal vesicles, depending on the site; 2) connection with the lateral pelvic fascia at the posterolateral angle of the prostate posterior to the neurovascular bundles, being clear, unclear, or absent; 3) all or most leaves of DF fused with the prostatic capsule near the base of the seminal vesicles, and periprostatic nerves were embedded in the leaves at the fusion site; and 4) some DF leaves fused with the prostatic capsule anteriorly and/or the fascia propria of the rectum posteriorly.

Conclusions

Site-dependent and interindividual variations in DF were observed in donated elderly male cadavers. All or most DF leaves are fused with the prostatic capsule near the base of the seminal vesicles and some DF leaves are fused with the fascia propria of the rectum posterior. Based on our results, surgeons should be aware of variations and search for them to create a suitable dissection plane to avoid iatrogenic positive margins and rectal injury.

Transanal endoscopic proctectomy and nerve injury risk: bottom to top surgical anatomy, key points

The transanal approach for rectal resection is a promising approach, because it increases the circumferential radial margin, especially for difficult cases. Meanwhile, functional sequelae are frequent after rectal cancer surgery and are often due to neurological lesions. There is little literature describing surgical anatomy from bottom to top. We combined our surgical experience with our fetal and adult anatomical research to provide a bottom-up surgical description focusing on neurological anatomy (see Video, Supplemental Digital Content 1, http://links.lww.com/DCR/A148).