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

Target Volume Optimization for Localized Prostate Cancer

PURPOSE

To provide a comprehensive review of the means by which to optimize target volume definition for the purposes of treatment planning for patients with intact prostate cancer with a specific emphasis on focal boost volume definition.

METHODS

Here we conduct a narrative review of the available literature summarizing the current state of knowledge on optimizing target volume definition for the treatment of localized prostate cancer.

RESULTS

Historically, the treatment of prostate cancer included a uniform prescription dose administered to the entire prostate with or without coverage of all or part of the seminal vesicles. The development of prostate magnetic resonance imaging (MRI) and positron emission tomography (PET) using prostate-specific radiotracers has ushered in an era in which radiation oncologists are able to localize and focally dose-escalate high-risk volumes in the prostate gland. Recent phase 3 data has demonstrated that incorporating focal dose escalation to high-risk subvolumes of the prostate improves biochemical control without significantly increasing toxicity. Still, several fundamental questions remain regarding the optimal target volume definition and prescription strategy to implement this technique. Given the remaining uncertainty, a knowledge of the pathological correlates of radiographic findings and the anatomic patterns of tumor spread may help inform clinical judgement for the definition of clinical target volumes.

CONCLUSION

Advanced imaging has the ability to improve outcomes for patients with prostate cancer in multiple ways, including by enabling focal dose escalation to high-risk subvolumes. However, many questions remain regarding the optimal target volume definition and prescription strategy to implement this practice, and key knowledge gaps remain. A detailed understanding of the pathological correlates of radiographic findings and the patterns of local tumor spread may help inform clinical judgement for target volume definition given the current state of uncertainty.

Development and growth of the temporal fascia: a histological study using human fetuses

The temporal fascia is a double lamina sandwiching a thick fat layer above the zygomatic bony arch. To characterize each lamina, their developmental processes were examined in fetuses. We observed histological sections from 22 half-heads of 10 mid-term fetuses at 14-18 weeks (crown-rump length, 95-150 mm) and 12 near-term fetuses at 26-40 weeks (crown-rump length, 215-334 mm). The superficial lamina of the temporal fascia was not evident at mid-term. Instead, a loose subcutaneous tissue was attached to the thin, deep lamina of the temporal fascia covering the temporalis muscle. At near-term, the deep lamina became thick, while the superficial lamina appeared and exhibited several variations: i) a mono-layered thick membrane (5 specimens); ii) a multi-layered membranous structure (6) and; iii) a cluster of independent thick fasciae each of which were separated by fatty tissues (1). In the second and third patterns, fatty tissue between the two laminae was likely to contain longitudinal fibrous bands in parallel with the deep lamina. Varying proportions of the multi-layered superficial lamina were not attached to the zygomatic arch, but extended below the bony arch. Whether or not lobulation or septation of fatty tissues was evident was not dependent on age. The deep lamina seemed to develop from the temporalis muscle depending on the muscle contraction. In contrast, the superficial lamina developed from subcutaneous collagenous bundles continuous to the cheek. Therein, a difference in development was clearly seen between two categories of the fasciae.

Short-term and long-term outcomes after robotic radical surgery for rectal gastrointestinal stromal tumor

BACKGROUND

The optimal approach for ensuring both complete resection and preservation of anal function in rectal gastrointestinal stromal tumor (GIST) remains unknown. The aim of this study was to clarify short-term and long-term outcomes after robotic radical surgery for rectal GIST.

METHODS

A total of 13 patients who underwent robotic radical surgery for rectal GIST between December 2011 and April 2022 were included. All robotic procedures were performed using a systematic approach. A supplemental video of robotic radical surgery for rectal GIST is attached. The short-term outcome was the incidence of postoperative complications during the first 30 days after surgery. Surgical outcomes were retrieved from a prospective database. Long-term outcomes, including overall survival and recurrence-free survival, were determined in all patients.

RESULTS

Median distance from the tumor to the anal verge was 4.0 cm. Surgical margins were negative in all patients. Two patients underwent neoadjuvant imatinib therapy. All patients underwent sphincter-preserving surgery. None underwent conversion to open or laparoscopic surgery. The incidence of postoperative Clavien-Dindo grade II and grade ≥ III complications was 7.7% and 0%, respectively. The median postoperative hospital stay was 7 days. Twelve patients (92.3%) underwent stoma closure within 5 months of the initial surgery. Median follow-up time was 76 months. The 5-year overall survival and recurrence-free survival rates were both 100%. None of the patients had recurrence.

CONCLUSION

Short-term and long-term outcomes after radical robotic surgery for rectal GIST were favorable. Robotic surgery might be a useful surgical approach for rectal GIST.

Denonvilliers' fascia as a potential nerve-course marker for the female urinary bladder

OBJECTIVES

This study investigated the relationship between Denonvilliers' fascia (DF) and the pelvic plexus branches in women and explored the possibility of using the DF as a positional marker in nerve-sparing radical hysterectomy (RH).

METHODS

This study included eight female cadavers. The DF, its lateral border, and the pelvic autonomic nerves running lateral to the DF were dissected and examined. The pelvis was cut into two along the mid-sagittal line. The uterine artery, deep uterine veins, vesical veins, and nerve branches to the pelvic organs were carefully dissected.

RESULTS

The nerves ran sagitally, while the DF ran perpendicularly to them. The rectovaginal ligament was continuous with the DF, forming a single structure. The DF attached perpendicularly and seamlessly to the pelvic plexus. The pelvic plexus branches were classified into a ventral part branching to the bladder, uterus, and upper vagina and a dorsal part branching to the lower vagina and rectum as well as into four courses. Nerves were attached to the rectovaginal ligament and ran on its surface to the bladder ventral to the DF. The uterine branches split from the common trunk of these nerves. The most dorsal branch to the bladder primarily had a common trunk with the uterine branch, which is the most important and should be preserved in nerve-sparing Okabayashi RH.

CONCLUSION

The DF can be used as a marker for nerve course, particularly in one of the bladder branches running directly superior to the DF, which can be preserved in nerve-sparing Okabayashi RH.

Preservation versus resection of Denonvilliers' fascia in total mesorectal excision for male rectal cancer: follow-up analysis of the randomized PUF-01 trial

Traditional total mesorectal excision (TME) for rectal cancer requires partial resection of Denonvilliers' fascia (DVF), which leads to injury of pelvic autonomic nerve and postoperative urogenital dysfunction. It is still unclear whether entire preservation of DVF has better urogenital function and comparable oncological outcomes. We conducted a randomized clinical trial to investigate the superiority of DVF preservation over resection (NCT02435758). A total of 262 eligible male patients were randomized to Laparoscopic TME with DVF preservation (L-DVF-P group) or resection procedures (L-DVF-R group), 242 of which completed the study, including 122 cases of L-DVF-P and 120 cases of L-DVF-R. The initial analysis of the primary outcomes of urogenital function has previously been reported. Here, the updated analysis and secondary outcomes including 3-year survival (OS), 3-year disease-free survival (DFS), and recurrence rate between the two groups are reported for the modified intention-to-treat analysis, revealing no significant difference. In conclusion, L-DVF-P reveals better postoperative urogenital function and comparable oncological outcomes for male rectal cancer patients.

Customized Denonvilliers' Fascia Excision: An Advanced Total Mesorectal Excision Technique for Anteriorly Located Rectal Cancer

BACKGROUND

The role of Denonvilliers' fascia in achieving a negative circumferential resection margin during anterior total mesorectal excision has been controversial. Opinions on whether to dissect in the anterior or posterior surgical plane varies among researchers.

IMPACT OF INNOVATION

We performed total mesorectal excision with selective en bloc resection of Denonvilliers' fascia based on preoperative MRI staging, preoperative clinical tumor stage, and tumor level in selected patients with anterior rectal tumors adherent to Denonvilliers' fascia.

TECHNOLOGY MATERIALS AND METHODS

Between March and August 2021, 5 patients who underwent robotic (n = 4) and laparoscopic (n = 1) total mesorectal excision for anteriorly located low rectal adenocarcinomas after neoadjuvant chemoradiotherapy were enrolled in this study. Transabdominal total mesorectal excision dissection is performed by changing to a plane anterior to Denonvilliers' fascia, with partial or total excision tailored to the tumor level and depth of invasion as a further step in circumferential resection margin clearing. Customized excision of Denonvilliers' fascia was performed by dissecting through the extramesorectal plane. This anterior plane permits resection of Denonvilliers' fascia, exposing the prostate and seminal vesicles.

PRELIMINARY RESULTS

Two tumors were located at the seminal vesicle level and 3 were found at the prostate level. The mean distance from the anal verge to the distal margin of the tumor was 4.8 ± 0.9 cm. Denonvilliers' fascia was preserved in 1 patient and partially excised in 4. Customized Denonvilliers' fascia excision was performed in 3 robotic ultralow anterior resections with coloanal anastomosis, 1 laparoscopic ultralow anterior resection with coloanal anastomosis, and 1 robot-assisted abdominoperineal resection. The circumferential resection margins in all patients were negative.

CONCLUSIONS AND FUTURE DIRECTIONS

Anterior dissection in front of Denonvilliers' fascia can be selectively performed during total mesorectal excision based on preoperative planning, tumor location, and clinical tumor stage. Preoperative MRI and magnified operative views in minimally invasive platforms provide access to more precise surgical planes for clear circumferential resection, achieving optimal functional outcomes and oncological safety.

Predictive factors associated with anastomotic leakage after resection of rectal cancer: a multicenter study with the Hiroshima Surgical study group of Clinical Oncology

PURPOSE

Several factors have been reported as risk factors for anastomotic leakage after resection of rectal cancer. This study aimed to evaluate the risk factors for anastomotic leakage, including nutritional and immunological indices, following rectal cancer resection.

METHODS

This study used a multicenter database of 803 patients from the Hiroshima Surgical study group of Clinical Oncology who underwent rectal resection with stapled anastomosis for rectal cancer between October 2016 and April 2020.

RESULTS

In total, 64 patients (8.0%) developed postoperative anastomotic leakage. Five factors were significantly associated with the development of anastomotic leakage after rectal cancer resection with stapled anastomosis: male sex, diabetes mellitus, C-reactive protein/albumin ratio ≥ 0.07, prognostic nutritional index < 40, and low anastomosis under peritoneal reflection. The incidence of anastomotic leakage was correlated with the number of risk factors. The novel predictive formula based on odds ratios in the multivariate analysis was useful for identifying patients at high risk for anastomotic leakage. Diverting ileostomy reduced the ratio of anastomotic leakage ≥ grade III after rectal cancer resection.

CONCLUSIONS

Male sex, diabetes mellitus, C-reactive protein/albumin ratio ≥ 0.07, prognostic nutritional index < 40, and low anastomosis under peritoneal reflection are possible risk factors for developing anastomotic leakage after rectal cancer resection with the stapled anastomosis. Patients at high risk of anastomotic leakage should be assessed for the potential benefits of diverting stoma.

The Mesentery in Robot-Assisted Total Mesorectal Excision

In recent decades, surgery for rectal cancer has evolved from an operation normally performed under poor vision with a lot of blood loss, relatively high morbidity, and mortality to a safer operation. Currently, minimally invasive rectal procedures are performed with limited blood loss, reduced morbidity, and minimal mortality. The main cause is better knowledge of anatomy and adhering to the principle of operating along embryological planes. Surgery has become surgery of compartments, more so than that of organs. So, rectal cancer surgery has evolved to mesorectal cancer surgery as propagated by Heald and others. The focus on the mesentery of the rectum has led to renewed attention to the anatomy of the fascia surrounding the rectum. Better magnification during laparoscopy and improved optimal three-dimensional (3D) vision during robot-assisted surgery have contributed to the refinement of total mesorectal excision (TME). In this chapter, we describe how to perform a robot-assisted TME with particular attention to the mesentery. Specific points of focus and problem solving are discussed.

Minimally invasive, 'en-bloc' seminal vesicle excision for locally advanced rectal adenocarcinoma: surgical technique and short-term outcomes

BACKGROUND

Isolated seminal vesicle invasion is a rare occurrence in patients with locally advanced rectal cancers. This study describes the surgical technique and the perioperative outcomes of minimally invasive 'en-bloc' seminal vesicle excision, preserving the bladder and the prostate.

METHODS

A retrospective review of 23 consecutive patients who underwent minimally invasive, en-bloc resection of seminal vesicles for locally advanced, non-metastatic rectal adenocarcinoma between May 2016 and November 2021. Perioperative outcomes and short-term oncological outcomes were defined.

RESULTS

Eighteen patients underwent a laparoscopic procedure while five received a robotic resection. All patients received preoperative radiation with or without consolidation chemotherapy. The median age was 42 years (range 20-64 years) and the median hospital stay was 8 days (range 3-19 days), respectively. Serious complications (Clavien-Dindo ≥ IIIb) were seen in six patients (26.1%). Two patients (8.7%) had an involved circumferential resection margin. At a median follow up of 19 months (range 2-52 months), four patients developed recurrences. The 2-year overall and disease-free survival was 84.4% and 73.6%, respectively.

CONCLUSION

Minimally invasive, en-bloc resection of one or both seminal vesicles for locally advanced rectal adenocarcinoma, is feasible in a select group of patients with acceptable morbidity and short-term outcomes.

Effect of partial preservation versus complete preservation of Denonvilliers' fascia on postoperative urogenital function in male patients with low rectal cancer (PREDICTION): protocol of a multicentre, prospective, randomised controlled clinical trial

INTRODUCTION

Total mesorectal excision (TME) has been the gold standard for the surgical treatment of mid-low rectal cancer, but traditional TME removal of Denonvilliers' fascia (DVF) is too low and is prone to damage the connecting branches of the bilateral neurovascular bundles, which can lead to posturogenital dysfunction. A recently published multicenter randomised controlled trial revealed that TME with complete preservation of DVF (CP-DVF) has protective effects on postoperative urogenital function for male patients with rectal cancer with specific staging and location (preoperative staging T1-4N0-2M0, but T1-2 for anterior rectal wall). Our previous studies have confirmed that TME with partial preservation of DVF (PP-DVF) could also achieve satisfactory results regardless of the circumferential location of the tumour. However, there is a lack of randomised controlled trials to prove that the efficacy of TME with PP-DVF is equivalent to that with CP-DVF with respect to postoperative urogenital function.

METHODS AND ANALYSIS

This study is a prospective, multicentre, equivalent design, open-label randomised clinical trial in which 278 male patients with low rectal cancer will be recruited from 11 large-scale gastrointestinal medical centres in China. Patients will be randomly assigned to undergo PP-DVF or CP-DVF. We will test the hypothesis that PP-DVF is similar to CP-DVF with respect to sexual function at postoperative month 12 (5-item version of the International Erectile Function Index Questionnaire and ejaculation function classification). The secondary outcomes include the assessment of urinary function, surgical safety and oncological outcomes.

ETHICS AND DISSEMINATION

This trial has been approved by the Institutional Review Board of Fujian Medical University Union Hospital (2020YF016-01) and is filed on record by all other centres. Written informed consent will be obtained from all eligible participants before enrolment. The trial's results will be disseminated via peer-reviewed scientific journals and conference presentations.

TRIAL REGISTRATION NUMBER

ChiCTR2000034892.

Denonvilliers’ Fascia: The Prostate Border to the Outside World

Simple Summary

Prostate cancer is a very common neoplasm in men, with surgery being a valuable tool for its successful management. The prostate gland lies deep in the male pelvis with several sheets of fibrous membranes surrounding it along anterior, lateral, and posterior surfaces. These membranes are called fasciae. Arteries, veins, and nerve fibers that are important for erectile function and continence can be found within these fasciae. An important fascia covering the posterior surface of the prostate and separating it from the rectum is Denonvilliers’ fascia. This structure is important for the confinement of cancer within the prostate and for completing an operation without damaging the nerves responsible for erectile function and continence while also removing all neoplastic tissue. This review covers the anatomical aspects of this structure, along with providing some clinical insight on how to use this knowledge to improve clinical outcomes.

Abstract

The fascial structure around the prostate has been a controversial issue for several decades, but its role in radical prostatectomy is crucial to achieving successful nerve-sparing surgery. One of the fasciae surrounding the prostate is Denonvilliers’ fascia, forming its posterior border with the rectum and enclosing along its layers several fibers of the neurovascular bundle. This review focuses on embryological and anatomical points of Denonvilliers’ fascia, aiming to provide a summary for the operating general surgeons and urologists of this area.

Trajectory of change of low anterior resection syndrome over time after restorative proctectomy for rectal adenocarcinoma

BACKGROUND

Restorative proctectomy for rectal cancer is associated with a high incidence of low anterior resection syndrome (LARS), but few studies report longitudinal results for bowel function. The aim of our study was to examine the trajectory of change of LARS over the first 18 months after restorative proctectomy for rectal cancer.

METHODS

A prospective database measuring functional outcomes in rectal cancer patients from a single university-affiliated specialist colorectal referral center from 10/2018 to 03/2020 was queried. Patients were included in this study if they underwent restorative proctectomy for rectal cancer and had at least three assessments in the first 18 months after primary surgery or after closure of proximal diversion. Bowel function was assessed using the LARS score, administered at every surveillance follow-up after restoration of bowel continuity. Latent-class growth curve (trajectory) analysis was used to identify different trajectories of LARS changes over the first 18 months and group patients into these trajectory groups. These groups were then compared to identify predictors for each trajectory.

RESULTS

A total of 95 patients were included (63 males, mean age. 61.3 ± 12.5 years). Trajectory analysis identified three distinct trajectory groups. Group 1 had stable minimal LARS over time (26%). Group 2 had early LARS scores consistent with the minor LARS category and improved with time (28%). Group 3 had persistently high LARS scores (45%). Neoadjuvant therapy, intersphincteric resection, and proximal diversion were more common in group 3.

CONCLUSIONS

We identified three main trajectories of change of LARS in the 18 months after restorative proctectomy. These data may be used to better inform patients of their expected postoperative bowel function.

Denonvilliers’ fascia acts as the fulcrum and hammock for continence after radical prostatectomy

Background

Radical prostatectomy (RP) is the primary treatment of localized prostate cancer. Immediate urinary incontinence post-RP was still common and depressing without specific reason.

Methods

A multicenter cohort of 154 consecutive patients from 2018 to 2020, who was diagnosed with localized prostate cancer underwent either modified mini-incision retropubic radical prostatectomy (Mmi-RRP) or laparoscopic radical prostatectomy (LRP) or robotic-assisted radical prostatectomy (RARP). Seventy-two patients with Denonvilliers’ fascia (DF) spared were included in DFS (Denonvilliers’ fascia sparing) group. Whereas eighty-two patients with DF completely or partially dissected were set as Group Control. The primary outcome was immediate continence (ImC). Continuous data and categorical data were analyzed with t-test and Chi-square test, respectively. Odds ratios (ORs) were calculated with logistic regression.

Results

Urinary continence of Group DFS was significantly better than that of Group Control at each time point within one year after operation. Incidence rate of continence in Group DFS and Group Control were 83.3% vs 13.4% (P < 0.01) for ImC, 90.3% vs 30.5% (P < 0.01) at 3 months, 91.7% vs 64.6% (P < 0.01) at 6 months, and 93.1% vs 80.5% (P = 0.02) at 1 year after operation, respectively. Positive surgical margin (PSM) showed no significant difference (20.8% vs 20.7%, P = 1.0). In multivariate analysis, DFS showed importance for ImC post RP (OR = 26.4, P < 0.01).

Conclusions

Denonvilliers’ fascia acted as the fulcrum and hammock for continence post RP. Preservation of DF contributed to better continence after RP without increase of PSM.

Trail registration Our research was conducted retrospectively and approved by the ethical committees of Minhang Hospital, but not registered.

Three-dimensional anatomy of the Denonvilliers' fascia after micro-CT reconstruction

An understanding of the anatomy of the Denonvilliers’ fascia is essential for successful surgical outcomes for patients with rectal cancer in the mid- to lower regions, especially near the seminal vesicles and prostate in males. Whether the correct surgical plane during a total mesorectal excision should be anterior or posterior to the Denonvilliers’ fascia is currently under debate. This study aimed to investigate the Denonvilliers’ fascia using micro-computed tomography (micro-CT) to acquire three-dimensional images nondestructively for assessments of the relationship between the Denonvilliers’ fascia, the mesorectal fascia, and neurovascular bundles to elucidate the correct anterior total mesorectal excision plane. Eight specimens were obtained bilaterally from four fresh human cadavers. Four specimens were stained with phosphotungstic acid to visualize the soft tissue, and micro-CT images were obtained; the other four specimens were stained with Masson’s trichrome to visualize connective tissue. Micro-CT images corroborate that the Denonvilliers’ fascia consists of a multilayered structure that separates the rectum from the seminal vesicles and the prostate. Specimens stained with Masson’s trichrome showed that the urogenital neurovascular bundle located at the posterolateral corner of the prostate is separated from the mesorectum by the Denonvilliers’ fascia. For the preservation of autonomic nerves necessary for urogenital function and optimal oncologic outcomes in patients with rectal cancer, a successful mesorectal excision requires a dissection plane posterior to the Denonvilliers’ fascia.

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.

Advantages of robotic abdominoperineal resection compared with laparoscopic surgery: a single-center retrospective study

PURPOSE

Although robotic surgery for rectal cancer can overcome the shortcomings of laparoscopic surgery, studies focusing on abdominoperineal resection are limited. The aim of this study was to compare the operative outcomes between robotic and laparoscopic abdominoperineal resection.

METHODS

This retrospective cohort study was conducted from April 2010 to March 2020. Patients with rectal cancer who underwent robotic or laparoscopic abdominoperineal resection without lateral lymph node dissection were enrolled. The perioperative and oncological outcomes were compared.

RESULTS

We evaluated 33 and 20 patients in the robotic and laparoscopic groups, respectively. The median operative time and blood loss were comparable between the two groups. No significant differences in the overall complication rates were noted, whereas the rates of urinary dysfunction (3% vs. 26%, p = 0.02) and perineal wound infection (9% vs. 35%, p = 0.03) in the robotic group were significantly lower in comparison to the laparoscopic group. The median postoperative hospital stay was significantly shorter in the robotic group (8 days vs. 11 days, p < 0.01). The positive resection margin rates were comparable between the two groups.

CONCLUSION

Robotic abdominoperineal resection demonstrated better short-term outcomes than laparoscopic surgery, suggesting that it could be a useful approach.

Outcomes of robotic partial excision of the levator ani muscle for locally advanced low rectal cancer invading the ipsilateral pelvic floor at the anorectal ring level

PURPOSE

The purpose of this study is to evaluate partial excision of the levator ani muscle (PELM) enables preservation of anal sphincter function although levator ani muscle (LAM) was invaded.

METHODS

Functional outcomes and oncologic outcomes of 23 consecutive patients who underwent robotic PELM for low rectal cancer at the anorectal ring level invading or abutting the ipsilateral LAM are analysed.

RESULTS

Secured resection margins were achieved, especially for the circumferential resection margin. During a median follow-up of 44 months, the 3-year local recurrence rate was 14.4%. Among patients who underwent diverting ileostomy closure, mean Memorial Sloan Kettering Cancer Center Bowel Function Instrument and Wexner scores were 68.3 ± 11.9 and 10.7 ± 5.3, respectively, at 1 year after closure.

CONCLUSION

PELM is a sphincter-preserving alternative to abdominoperineal resection (APR) or extralevator APR for low rectal cancer invading the ipsilateral LAM at the level of the anorectal ring.

Short- and Long-Term Outcomes of Robotic Surgery for Rectal Neuroendocrine Tumor

Background. The optimal radical surgical approach for rectal neuroendocrine tumor (NET) is unknown. Methods. This study evaluated the short- and long-term outcomes of 27 patients who underwent robotic radical surgery for rectal NET between 2011 and 2019. Results. The median distance from the lower border of the tumor to the anal verge was 5.0 cm. The median tumor size was 9.5 mm. Six patients (22%) had lymph node metastasis. The incidences of postoperative complications of grade II and grade III or more according to the Clavien-Dindo classification were 11% and 0%, respectively. All patients underwent sphincter-preserving surgery, and no patients required conversion to open surgery. The median follow-up time was 48.9 months, and both the 3-year overall survival and relapse-free survival rates were 100%. Conclusions. Short- and long-term outcomes of robotic surgery for rectal NET tumor were favorable. Robotic surgery may be a useful surgical approach for rectal NET.

Initial experience of Chinese surgical robot "Micro Hand S″ assisted versus open and laparoscopic total mesorectal excision for rectal cancer: Short-term outcomes in a single center

BACKGROUND

A Chinese surgical robot, Micro Hand S, was introduced for clinical use as a novel robotic platform. This study aimed to comprehensively compare the early experience of the Micro Hand S robot-assisted total mesorectal excision (TME) with conventional approaches.

METHODS

Between May 2017 and April 2018, 99 consecutive patients who underwent open, laparoscopic and Micro Hand S robot-assisted TME (O-/L-/RTME) for rectal cancer were included. Clinical and pathological outcomes were retrospectively analyzed. Surgical success as the primary endpoint was defined as the absence of (i) conversion, (ii) incomplete TME, (iii) involved circumferential and distal resection margins (CRM/DRM), (iv) severe complications.

RESULTS

The rate of surgical success was similar (89.7 vs. 86.4 vs. 84.6%, p = 0.851) in the three groups and the respective incidences were as follows: conversion (not applicable, 4.5 vs. 2.3%, p = 1.000), incomplete TME (6.9 vs. 6.8 vs. 3.8%, p = 0.980), involved CRM/DRM (0 vs. 2.3 vs. 3.8%, p = 0.592), severe complications (3.4 vs. 4.5 vs. 7.7%, p = 0.844). Compared with open and laparoscopic surgery, the robotic surgery was associated with longer operative time, less blood loss, earlier first flatus time and liquid intake time, and shorter length of hospital stay (p < 0.05).

CONCLUSIONS

The Micro Hand S assisted TME is safe and feasible, showing comparable outcomes than conventional approaches, with superiority in blood loss, recovery of bowel function, length of hospital stay, but with increased operative time.

Potential urinary function benefits of initial robotic surgery for rectal cancer in the introductory phase

We aimed to evaluate the advantages and disadvantages of initial robotic surgery for rectal cancer in the introduction phase. This study retrospectively evaluated patients who underwent initial robotic surgery (n = 36) vs. patients who underwent conventional laparoscopic surgery (n = 95) for rectal cancer. We compared the clinical and pathological characteristics of patients using a propensity score analysis and clarified short-term outcomes, urinary function, and sexual function at the time of robotic surgery introduction. The mean surgical duration was longer in the robot-assisted laparoscopy group compared with the conventional laparoscopy group (288.4 vs. 245.2 min, respectively; p = 0.051). With lateral pelvic lymph node dissection, no significant difference was observed in surgical duration (508.0 min for robot-assisted laparoscopy vs. 480.4 min for conventional laparoscopy; p = 0.595). The length of postoperative hospital stay was significantly shorter in the robot-assisted laparoscopy group compared with the conventional laparoscopy group (15 days vs. 13.0 days, respectively; p = 0.026). Conversion to open surgery was not necessary in either group. The International Prostate Symptom Score was significantly lower in the robot-assisted laparoscopy group compared with the conventional laparoscopy group. Moderate-to-severe symptoms were more frequently observed in the conventional laparoscopy group compared with the robot-assisted laparoscopy group (p = 0.051). Robotic surgery is safe and could improve functional disorder after rectal cancer surgery in the introduction phase. This may depend on the surgeon’s experience in performing robotic surgery and strictly confined criteria in Japan.

Perirectal Fascial Anatomy: New Insights Into an Old Problem

BACKGROUND

The architecture of perirectal fasciae is complex as mirrored by different anatomical concepts.

OBJECTIVE

This study aimed to perform a comprehensive visualization of perirectal fasciae to facilitate strategies of rectal surgery such as total mesorectal excision, intersphincteric resection, and transanal total mesorectal excision.

DESIGN

Macroscopic dissection and histologic studies of perirectal fasciae and autonomic pelvic nerves were performed.

SETTINGS

This study was conducted in a university laboratory of macroscopic and microscopic anatomy.

PATIENTS

Thirteen (5 female) pelvic specimens were obtained from body donors (67-92 years of age).

MAIN OUTCOME MEASURES

The primary outcomes measured were the photodocumentation of perirectal fasciae, spaces and fusion zones, and histologic and immunohistochemical analysis of key structures.

RESULTS

The retrorectal space is a mesofascial interface between the mesorectal fascia and the parietal pelvic fascia. The parietal pelvic fascia is composed of 2 lamellae ensheathing the autonomic pelvic nerves. The outer lamella of the parietal pelvic fascia and the presacral fascia confine the presacral space. The presacral fascia covers the median sacral blood vessels. Approximately at the fourth sacral vertebra, all fascial layers fuse in the midline and are densely connected to the posterior rectal wall via the rectosacral ligament. The parietal pelvic fascia fuses with the pubococcygeal and longitudinal rectal muscles at the anorectal junction. Anterolaterally, the neurovascular bundles are closely related to this fascial fusion zone and the rectogenital septum.

LIMITATIONS

Because of the increased age of the body donors, the findings may be subjected to age-related degenerative processes.

CONCLUSIONS

The 2 lamellae of the parietal pelvic fascia and the fascial fusion zones are key structures of perirectal anatomy. For autonomic nerve preservation, the recognition of the inner lamella of the parietal pelvic fascia is crucial. To avoid inadvertent rectal perforation or accidental presacral dissection, the rectosacral ligament must be identified and transected for complete rectal mobilization. See Video Abstract at http://links.lww.com/DCR/B389. ANATOMÍA FASCIAL PERIRRECTAL: NUEVOS CONCEPTOS SOBRE UN ANTIGUO PROBLEMA: La arquitectura de las fascias perirrectales es compleja, reflejada por distintos conceptos anatómicos.Integración de conceptos sobre las fascias perirrectales para facilitar las estrategias de cirugía rectal, como la escisión mesorrectal total, la resección interesfintérica y la escisión mesorrectal total transanal.Disección macroscópica y estudios histológicos de fascias perirrectales y nervios pélvicos autonómicos.Laboratorio universitario de anatomía macroscópica y microscópica.Trece (5 mujeres) muestras pélvicas obtenidas de donantes de cuerpo (67-92 años).Foto documentación de fascias perirrectales, espacios y zonas de fusión, análisis histológico e inmunohistoquímico de estructuras claves.El espacio retrorectal es una interfaz mesofascial entre la fascia mesorrectal y la fascia pélvica parietal. Este último se compone de dos láminas que envuelven los nervios pélvicos autonómicos. La lámina externa de la fascia pélvica parietal y la fascia presacra definen el espacio presacro. La fascia presacra cubre los vasos sanguíneos sacros medianos. Aproximadamente en la cuarta vértebra sacra, todas las capas fasciales se unen en la línea media y están densamente conectadas a la pared rectal posterior a través del ligamento rectosacro. La fascia pélvica parietal se une con los músculos rectal pubococcígeo y longitudinal en la unión anorrectal. Anterolateralmente, los haces neurovasculares están estrechamente relacionados con esta zona de fusión fascial y el tabique rectogenital.Debido al aumento de la edad de los donantes de cuerpos, los hallazgos pueden estar sujetos a procesos degenerativos relacionados con la edad.Las dos láminas de la fascia pélvica parietal y las zonas de fusión fascial son estructuras claves de la anatomía perirrectal. Para la preservación del nervio autónomo de nervios pélvicos autonómicos, el reconocimiento de la lámina interna de la fascia pélvica parietal es importante. Para evitar la perforación rectal inadvertida o la disección presacra accidental, el ligamento rectosacro debe ser identificado y seccionado para una movilización rectal completa. Consulte Video Resumen en http://links.lww.com/DCR/B389.

Essential anatomy for total mesorectal excision and lateral lymph node dissection, in both trans-abdominal and trans-anal perspective

BACKGROUND AND PURPOSE

Total Mesorectal Excisions (TME) is the standard treatment of rectal cancer. It can be performed under laparoscopic, robotic or transanal approach. Inadvertent injury to surrounding structure like autonomic nerves is avoidable, no matter which approach is adopted. Lateral lymph node dissection (LLND) is a less commonly performed pelvic operation involving dissection in an unfamiliar area to most general surgeons. This article aims to clarify all the essential anatomy related to these procedures.

METHODS

We performed thorough literature search and revision on the pelvic anatomy. Our cases of TME and LLND, under either laparoscopic or transanal approach, were reviewed. We integrated the knowledge from literatures and our own experience. The result was presented in details, together with original figures and intra-operative photos.

MAIN FINDINGS

Anatomy of pelvic fascia, autonomic nerve system, anal canal and sphincter complex are core knowledge in performing TME and LLND.

CONCLUSIONS

Thorough understanding of the pelvic anatomy enables colorectal surgeons to master these procedures, avoid complication and perform extended resection. On the other hand, surgeons can appreciate the complex pelvic anatomy easier by seeing the pelvis in opposite angles (transabdominal and transaanal view).

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.

Identification of the surgical indication line for the Denonvilliers' fascia and its anatomy in patients with rectal cancer

Background

The high rate of urogenital dysfunction after traditional total mesorectal excision (TME) has caused doubts among scholars on the standard fashion of dissection. We have proposed the necessity to preserve the Denonvilliers’ fascia in patients with rectal cancer. However, how to accurately locate the Denonvilliers’ fascia is unclear. This study aimed to explore anatomical features of the Denonvilliers’ fascia by comparing autopsy findings and observations of surgical videos so as to propose a dissection method for the preservation of pelvic autonomic nerves during rectal cancer surgery.

Methods

Five adult male cadaver specimens were dissected, and surgical videos of 135 patients who underwent TME for mid‐low rectal cancer between January 2009 and February 2019 were reviewed to identify and compare the structure of the Denonvilliers’ fascia.

Results

The monolayer structure of the Denonvilliers’ fascia was observed in 5 male cadaver specimens, and it was located between the rectum, the bottom of the bladder, the seminal vesicles, the vas deferens, and the prostate. The Denonvilliers’ fascia was originated from the rectovesical pouch (or rectum‐uterus pouch), down to fuse caudally with the rectourethral muscle at the apex of the prostate, and fused to the lateral ligaments on both sides. The fascia was thinner on the midline with a thickness of 1.06 ± 0.10 mm. The crown shape of the Denonvilliers’ fascia was slightly triangular, with a height of approximately 5.42 ± 0.16 cm at midline. Nerves were more densely distributed in front of the Denonvilliers’ fascia than behind, especially on both sides of it. Under laparoscopic view, the Denonvilliers’ fascia was originated at the lowest point of the rectovesical pouch (or rectum‐uterus pouch), with a thickened white line which was a good mark for identifying the Denonvilliers’ fascia.

Conclusion

Identification of the surgical indication line for the Denonvilliers’ fascia could help us identify the Denonvilliers’ fascia, and it would improve our ability to protect the pelvic autonomic function of patients undergoing TME for rectal cancer.

Detailed and applied anatomy for improved rectal cancer treatment

Rectal anatomy is one of the most challenging concepts of visceral anatomy, even though currently there are more than 23,000 papers indexed in PubMed regarding this topic. Nonetheless, even though there is a plethora of information meant to assist clinicians to achieve a better practice, there is no universal understanding of its complexity. This in turn increases the morbidity rates due to iatrogenic causes, as mistakes that could be avoided are repeated. For this reason, this review attempts to gather current knowledge regarding the detailed anatomy of the rectum and to organize and present it in a manner that focuses on its clinical implications, not only for the colorectal surgeon, but most importantly for all colorectal cancer-related specialties.

Reconsideration of the Anterior Surgical Plane of Total Mesorectal Excision for Rectal Cancer

INTRODUCTION

Previous studies on total mesorectal excision suggested dissection anterior to Denonvilliers' fascia, which might lead to intraoperative pelvic autonomic nerves injury and a high incidence of urogenital dysfunction.

TECHNIQUE

We dissected 4 cases of cadavers, mainly focusing on anatomy of Denonvilliers' fascia, to study the relationship between Denonvilliers' fascia and rectum. In practice, instead of dissection 1 cm above peritoneal reflection, dissection of the peritoneum was performed at the lowest level of peritoneal reflection during laparoscopic resection for mid-low rectal cancer.

RESULTS

The cadaveric study revealed that there were loose tissues between Denonvilliers' fascia and rectal specimen, thus a surgical plane posterior to Denonvilliers' fascia did exist. During laparoscopic resection for mid-low rectal cancer, some loose reticulate structures between Denonvilliers' fascia and proper fascia of rectum would present after dissection of peritoneum at the lowest level of peritoneal reflection. Then dissection within the surgical plane posterior to Denonvilliers' fascia became easy and feasible. In this plane, both the pelvic nerves and postoperative urogenital function could be well protected by Denonvilliers' fascia.

CONCLUSIONS

The anterior surgical plane for total mesorectal excision should be reconsidered, and dissection posterior to Denonvilliers' fascia is feasible and practicable for patients without risk of positive anterior circumferential resection margin.

Surgical and histological boundary of the hepatic hilar plate system: basic study relevant to surgery for hilar cholangiocarcinoma regarding the "true" proximal ductal margin

BACKGROUND

We sought to expand the clinico-anatomical limit of the proximal ductal margin (Limit-PDM) for resectability of hilar cholangiocarcinoma (HCCA).

METHODS

The practical boundary of the hilar plate (PBHP) was defined as the location where the bile duct (BD) could not be isolated by dissection. The distance between PBHP and two well-known clinical landmarks of Limit-PDM, the right edge of the bifurcation of the anterior and posterior branch of the right portal vein (Posterior-Landmark) and the left edge of the umbilical portion of the portal vein (Left-Landmark), and histological features around the PBHP were assessed using 55 adult cadaver livers.

RESULTS

BD was almost always isolatable beyond the traditional clinical landmarks. The median distance was 6.9 mm (interquartile range [IQR] 6.0-8.3 mm) between the PBHP and the Posterior-Landmark, and 8.9 mm (IQR 6.7-10.2 mm) between the PBHP and the Left-Landmark. Histologically, the sheath surrounding the portal triad was loose, thick with few elastic fibers and small arteries near the hepatic hilum. Near the PBHP, the sheath was dense, thin, and abundant with elastic fibers and small arteries.

CONCLUSIONS

Limit-PDM is more peripheral than the traditional clinical landmark-based margin and histological transition near the PBHP was revealed.

Preservation of Denonvilliers' fascia for nerve-sparing laparoscopic total mesorectal excision: A neuro-histological study

Urogenital complications due to pelvic autonomic nerve damage frequently occur following rectal surgery. We investigated whether total mesorectal excision (TME) with preservation of the Denonvilliers' fascia (DVF) can effectively prevent the removal of pelvic autonomic nerves through microscopy. Twenty consecutive male patients with mid-low rectal cancer who received TME with preservation or resection of the Denonvilliers' fascia (P and R groups, respectively) were included. Serial transverse sections from surgical specimens were studied histologically. Nerve fibers at the surfaces of the mesorectum were counted. Clinical correlation between the amount of nerve fibers removed and post-operative sexual function was analyzed. Nerve fibers closely localized to the DVF in the R group displaying rich erectile activity (positive anti-nNOS immunostaining). At the anterior surface of the mesorectum, the mean numbers of nNOS-positive nerve fibers per specimen in the P group were significantly lower than the R group (3.0 ± 1.8 vs. 5.0 ± 2.3, P < 0.05). Compared to the R group, patients in the P group had higher IIEF scores and better erectile function at 3 and 6 months post-operatively. The DVF is a key risk zone for pelvic denervation during laparoscopic TME. Preservation of the DVF can prevent the removal of autonomic nerves and protect post-operative erectile function. Clin. Anat. 32:439-445, 2019. © 2019 Wiley Periodicals, Inc.

Short- and long-term outcomes of robotic-assisted laparoscopic surgery for rectal cancer: results of a single high-volume center in Japan

PURPOSE

Scientific evidence supporting robotic-assisted laparoscopic surgery (RALS) for rectal cancer remains inconclusive because most previous reports were retrospective case series or case-control studies, with few reports focusing on long-term oncological outcomes with a large volume of patients. The aim of this study was to clarify the short- and long-term outcomes of a large number of consecutive patients with rectal cancer who underwent RALS in a single high-volume center.

METHODS

The records of 551 consecutive patients who underwent RALS for rectal adenocarcinoma between December 2011 and March 2017 were examined to reveal the short-term outcomes. The oncological outcomes of the 204 patients who underwent surgery between December 2011 and March 2014 were evaluated.

RESULTS

Most patients had tumors located in the lower or mid-rectum (86.0%). Only 7.6% of patients underwent neoadjuvant chemoradiotherapy. Lateral lymph node dissection was performed for 191 patients (34.7%). The median operative time was 257 min, median blood loss was 10 mL, and no transfusions were needed. No conversion to open surgery was necessary. Eighteen patients (3.3%) had Clavien-Dindo grade III postoperative complications. Six patients (1.1%) had positive resection margins. The mean follow-up duration of the 204 patients was 43.6 ± 9.8 (months). The 5-year cancer-specific survival rate for stage I/II/III/IV was 100%/100%/100%/not reached, respectively. The 5-year relapse-free survival rate for stage I/II/III/IV was 93.6%/75.0%/77.6%/ not reached, respectively. The rate of local recurrence was 0.5%.

CONCLUSIONS

Our results suggest that RALS is technically feasible for rectal cancer and has good short- and long-term outcomes.

The impact of robotic surgery on quality of life, urinary and sexual function following total mesorectal excision for rectal cancer: a propensity score-matched analysis with laparoscopic surgery

AIM

Quality of life (QoL) and functional outcomes are at risk of being impaired after rectal surgery, but there has been no large prospective study to thoroughly assess QoL according to surgical approach. We have investigated the impact of laparoscopic and robotic total mesorectal excision (TME) on QoL and functional outcomes.

METHOD

Patients undergoing laparoscopic or robotic TME for rectal cancer between 2009 and 2013 were prospectively included in this questionnaire-based survey of QoL together with variations in urinary and sexual function. A propensity score analysis was retrospectively conducted to compare outcomes between groups in a cohort matched 1:1 for age, sex, body mass index, preoperative chemoradiation status and tumour height. The survey was performed preoperatively and 3, 6 and 12 months after surgery.

RESULTS

Global health status/QoL was similar between the two groups for 130 matched pairs, but the robotic group showed better role, emotional and social functioning and experienced less fatigue and financial difficulty. International Prostatic Symptom Scores in men increased postoperatively, with significantly less impairment in the robotic group at 6 months. These scores were comparable to preoperative scores at 6 months in the robotic group and at 12 months in the laparoscopic group. Of 48 sexually active men in each group, International Index of Erectile Function-5 scores decreased postoperatively, returning to preoperative levels at 6 months in the robotic group and at 12 months in the laparoscopic groups.

CONCLUSION

The robotic approach for TME was associated with less impairment of urinary and sexual function; QoL was comparable to the laparoscopic approach.

Essential Anatomy of the Anorectum for Colorectal Surgeons Focused on the Gross Anatomy and Histologic Findings

The anorectum is a region with a very complex structure, and surgery for benign or malignant disease of the anorectum is impossible without accurate anatomical knowledge. The conjoined longitudinal muscle consists of smooth muscle from the longitudinal muscle of the rectum and the striate muscle from the levator ani and helps maintain continence; the rectourethralis muscle is connected directly to the conjoined longitudinal muscle at the top of the external anal sphincter. Preserving the rectourethralis muscle without damage to the carvernous nerve or veins passing through it when the abdominoperineal resection is implemented is important. The mesorectal fascia is a multi-layered membrane that surrounds the mesorectum. Because the autonomic nerves also pass between the mesorectal fascia and the parietal fascia, a sharp pelvic dissection must be made along the anatomic fascial plane. With the development of pelvic structure anatomy, we can understand better how we can remove the tumor and the surrounding metastatic lymph nodes without damaging the neural structure. However, because the anorectal anatomy is not yet fully understood, we hope that additional studies of anatomy will enable anorectal surgery to be performed based on complete anatomical knowledge.

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.

Morphological study of the neurovascular bundle to elucidate nerve damage in pelvic surgery

PURPOSE

Postoperative sexual and urinary dysfunction may occur after rectal cancer surgery involving the pelvis, but this problem cannot be solved. The aim of this study was to examine the nerve morphology of the neurovascular bundle in cadavers to determine possible causes of nerve damage during surgery.

METHODS

Twenty-two formalin-fixed cadavers were used in the study. The cadavers were donated to the Tokyo Medical University. The study comprised histological evaluation of paraffin-embedded bilateral neurovascular bundle specimens from the cadavers. Four slides of 3-cm thick were made every 1 cm in a plane perpendicular to the rectum towards the pelvic floor from the peritoneal reflection in bilateral neurovascular bundles in 22 cadavers. The number of nerves, the mean nerve area, and the mean nerve diameter were measured in each slide.

RESULTS

The results were categorized into cases with high (group H) and low (group L) positions of the pelvis 1 cm above and 2 cm below the peritoneal reflection, respectively. There was no significant difference in the number of nerves between these groups. The nerve area and nerve diameter were significantly smaller in group L, and these characteristics were more marked in males.

CONCLUSIONS

Our results show that the nerves of the neurovascular bundle became smaller in the deep pelvis. This may cause these nerves to be more susceptible to injury, resulting in nerve damage in the deep pelvis that leads to postoperative dysfunction. Particularly, this type of nerve damage may be a cause of postoperative sexual dysfunction in males.

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.

Whole mount microscopic sections reveal that Denonvilliers' fascia is one entity and adherent to the mesorectal fascia; implications for the anterior plane in total mesorectal excision?

BACKGROUND

Excellent anatomical knowledge of the rectum and surrounding structures is essential for total mesorectal excision (TME). Denonviliers' fascia (DVF) has been frequently studied, though the optimal anterior plane in TME is still disputed. The relationship of the lateral edges of DVF to the autonomic nerves and mesorectal fascia is unclear. We studied whole mout microscopic sections of en-bloc cadaveric pelvic exenteration and describe implications for TME.

METHODS

Four donated human adult cadaveric specimens (two males, two females) were obtained from the Leeds GIFT Research Tissue Programme. Paraffin-embedded mega blocks were produced and serially sectioned at 50 and 250 μm intervals. Sections were stained with haematoxylin & eosin, Masson's trichrome and Millers' elastin. Additionally, a series of eleven human fetal specimens (embryonic age of 9-20 weeks) were studied.

RESULTS

DVF consisted of multiple fascial condensations of collagen and smooth muscle fibres and was indistinguishable from the anterior mesorectal fascia and the prostatic fascia or posterior vaginal wall. The lateral edges of DVF appeared fan-shaped and the most posterior part was continuous with the mesorectal fascia. Fasciae were not identified in fetal specimens.

CONCLUSION

DVF is adherent to and continuous with the mesorectal fascia. Optimal surgical dissection during TME should be carried out anterior to DVF to ensure radical removal, particularly for anterior tumours. Autonomic nerves are at risk, but can be preserved by closely following the mesorectal fascia along the anterolateral mesorectum. The lack of evident fasciae in fetal specimens suggested that these might be formed in later developmental stages.

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).

Denonvilliers' fascia revisited

Although several studies have reported that the peritoneum does not contribute to the formation of a fascia between the urogenital organs and rectum, Denonvilliers' fascia (DF), a fascia between the mesorectum and prostate (or vagina) in adults, is believed to be a remnant of the peritoneum. Remnants of the peritoneum, however, were reportedly difficult to detect in other fusion fasciae of the abdominopelvic region in mid-term fetuses. To examine morphological changes of the pelvic cul-de-sac of the peritoneum, we examined 18 male and 6 female embryos and fetuses. A typical cul-de-sac was observed only at 7 weeks, whereas, at later stages, the peritoneal cavity did not extend inferiorly to the level of the prostatic colliculus or the corresponding structure in females. The cul-de-sac had completely disappeared in front of the rectum at 8 weeks and homogeneous and loose mesenchymal tissue was present in front of the rectum at the level of the colliculus at 12-16 weeks. We found no evidence that linearly arranged mesenchymal cells developed into a definite fascia. Therefore, the development of the DF in later stages of fetal development may result from the mechanical stress on the increased volumes of the mesorectum, seminal vesicle, prostate and vagina and/or enlarged rectum. Therefore, we considered the DF as a tension-induced structure rather than a fusion fascia. Fasciae around the viscera seemed to be classified into (1) a fusion fascia, (2) a migration fascia and (3) a tension-induced fascia although the second and third types are likely to be overlapped.

Optimal plane for nerve sparing total mesorectal excision, immunohistological study and 3D reconstruction: an embryological study

AIM

Genito-urinary complications are frequent after rectal surgery and are often due to nerve damage. The relationship between the pelvic nerves and surgical planes are unclear. The aim of the study was to determine the relationship between the inferior hypogastric plexus and the fascia of the lateral pelvic wall and between Denonvilliers' fascia and the efferent branches of the inferior hypogastric plexus.

METHOD

Computer-assisted anatomical dissection was used. Serial histological sections were made from six human foetuses and a male adult. Sections were stained with haematoxylin and eosin, Masson's trichrome and immunostainings. The sections were then digitalized and reconstructed in three dimensions.

RESULTS

The inferior hypogastric plexus was situated in a virtual space between the fascia propria of the rectum and the fascia on the upper surface of the levator ani. During the lateral dissection, the optimal surgical plane is the plane of the fascia propria of the rectum. We located Denonvilliers' fascia in three dimensions. It plays the role of a protective sheet for the neurovascular bundle. The optimal plane for nerve preservation is situated behind Denonvilliers' fascia.

CONCLUSION

This study has enabled a clear visualization of the optimal planes to perform total mesorectal excision while ensuring nerve preservation. Three-dimensional visualization clearly helps to bridge the gap between histological examination and the findings of surgery.

Comparison of tumor recurrence between laparoscopic total mesorectal excision with sphincter preservation and laparoscopic abdominoperineal resection for low rectal cancer

BACKGROUND

By traditional open surgery, the tumor recurrence rate of total mesorectal excision with sphincter-preserving procedure was lower than that of abdominoperineal resection (APR) for the treatment of low rectal cancer. The present study aimed to rescrutinize whether the same conclusion can be drawn when both surgical procedures are performed laparoscopically.

METHODS

We retrospectively reviewed the prospectively recorded clinicopathologic data of 344 consecutive patients with low rectal cancer, in which 170 patients underwent preoperative chemoradiotherapy followed by laparoscopic total mesorectal excision (TME), whereas 174 patients underwent laparoscopic TME directly without chemoradiotherapy. Such patients were further stratified according to the pathologic tumor, node, metastasis stage (stage II or III disease) and surgical strategy (APR or sphincter-preserving operation [SPO]). The surgical procedures are presented in supplemental videos. The disease-free survival, recurrence patterns, and functional recovery of patient groups stratified as appropriate were compared.

RESULTS

In patients who received preoperative chemoradiotherapy, the estimated recurrence rate were similar between laparoscopic TME with SPO and laparoscopic APR with 10.6%, 7 of 66, versus 18.5%, 5 of 27, in stage II disease (p = 0.811, log-rank test); and 19.3%, 11 of 57, versus 20%, 4 of 20, in stage III disease (p = 0.980). In patients without preoperative chemoradiotherapy, the recurrence rate was significantly higher in laparoscopic APR than in the laparoscopic TME with SPO group of patients with stage III disease (45%, 9 of 20, vs. 19.3%, 16 of 83, p = 0.025), whereas the recurrence rate of the two procedures was similar (21.4%, 3 of 14, vs. 17.5%, 10 of 57, p = 0.702) in stage II disease.

CONCLUSIONS

When low rectal cancer was operated on by laparoscopic approach, the poorer prognosis of APR compared to SPO was only observed in stage III patients without preoperative chemoradiotherapy.

Male sexual function after laparoscopic total mesorectal excision

AIM

The aim of this prospective study was to clarify the frequency of male sexual dysfunction after laparoscopic total mesorectal excision (LTME) and to examine the relationship between pelvic autonomic nerve (PAN) preservation status and functional outcomes.

METHOD

Candidates for LTME were included in this study. PAN preservation status after LTME was examined in detail by video review. Patients completed a functional questionnaire (the International Index of Erectile Function) before and 3, 6 and 12 months after the operation.

RESULTS

Twenty-six patients who underwent LTME were assessable. Detailed video reviews identified inadvertent PAN damage during surgery. PAN injury was observed in 11 cases (41%), including eight cases (32%) of inadvertent PAN damage (incomplete preservation group). There was a trend toward increasing inadvertent PAN injury rate in patients with high body mass index and large tumours. The results from all patients who underwent LTME showed no deterioration in total International Index of Erectile Function or its domain scores 12 months after surgery. In the incomplete preservation group, these scores temporarily decreased (3 and 6 months after surgery), but such deterioration was not observed in the complete preservation group. Most of the 12 patients with potentially active erectile function before the operation recovered this function, and only one patient (7%) with PAN injury was still judged as inactive 12 months after surgery.

CONCLUSION

The proportion of patients with sexual dysfunction after LTME is low. With the enhanced visibility of the laparoscope, inadvertent PAN injury was detected in a significant number of cases and associated with transient deterioration of sexual function.