Embryonic developmental process and clinical anatomy of the preperitoneal fascia and its clinical significance.

PURPOSE: Many researchers have different views on the origin and anatomy of the preperitoneal fascia. The purpose of this study is to review studies on the anatomy related to the preperitoneal fascia and to investigate the origin, structure, and clinical significance of the preperitoneal fascia in conjunction with previous anatomical findings of the genitourinary fascia, using the embryogenesis of the genitourinary system as a guide. METHODS: Publications on the preperitoneal and genitourinary fascia are reviewed, with emphasis on the anatomy of the preperitoneal fascia and its relationship to the embryonic development of the genitourinary organs. We also describe previous anatomical studies of the genitourinary fascia in the inguinal region through the fixation of formalin-fixed cadavers. RESULTS: Published literature on the origin, structure, and distribution of the preperitoneal fascia is sometimes inconsistent. However, studies on the urogenital fascia provide more than sufficient evidence that the formation of the preperitoneal fascia is closely related to the embryonic development of the urogenital fascia and its tegument. Combined with previous anatomical studies of the genitourinary fascia in the inguinal region of formalin-fixed cadavers showed that there is a complete fascial system. This fascial system moves from the retroperitoneum to the anterior peritoneum as the preperitoneal fascia. CONCLUSIONS: We can assume that the preperitoneal fascia (PPF) is continuous with the retroperitoneal renal fascia, ureter and its accessory vessels, lymphatic vessels, peritoneum of the bladder, internal spermatic fascia, and other peritoneal and pelvic urogenital organ surfaces, which means that the urogenital fascia (UGF) is a complete fascial system, which migrates into PPF in the preperitoneal space and the internal spermatic fascia in the inguinal canal.

Peritoneal disease: key imaging findings that help in the differential diagnosis.

The peritoneum is a unique serosal membrane, which can be the site of primary tumors and, more commonly, secondary pathologic processes. Peritoneal carcinomatosis is the most common malignant condition to affect the peritoneal cavity, and the radiologist plays an important role in making the diagnosis and assessing the extent of disease, especially in sites that may hinder surgery. In this review, we address the role of the radiologist in the setting of peritoneal pathology, focusing on peritoneal carcinomatosis as this is the predominant malignant process, followed by revising typical imaging findings that can guide the differential diagnosis.We review the most frequent primary and secondary peritoneal tumor and tumor-like lesions, proposing a systemic approach based on clinical history and morphological appearance, namely distinguishing predominantly cystic from solid lesions, both solitary and multiple.

Assessment of peritoneal thickness using CT in relation to dialysis adequacy in peritoneal dialysis patients.

Studies assessing peritoneal thickness by CT in peritoneal dialysis (PD) patients are lacking. In this study, we aimed to investigate the association between peritoneal thickness as measured by CT and dialysis adequacy with peritoneal membrane characteristics in PD patients. Ninety-four PD patients were enrolled. Peritoneal thickness was measured by CT. Patients with and without a decrease in Kt/V of at least 0.3 over time were classified as Group 1 and Group 2, respectively. An increase of 0.1 unit of dialysate/plasma (D/P) creatinine over time were considered significant. The relationship between peritoneal membrane thickness, change in Kt/V, and peritoneal membrane characteristics were investigated. There were 31 (33.0%) patients in Group 1. The duration of PD (86.0 ± 64.1 vs. 59.6 ± 45.2 months, p: 0.023), peritoneal thickness (1.02 ± 0.37 vs. 0.87 ± 0.21 mm, p: 0.015), peritoneal calcification (7 [22.6%] vs. 3 [4.8%] patients, p: 0.013], increased D/P creatinine ratio (14 [45.2%] vs. 14 [22.2%] patients, p: 0.031) and CRP (13.9 ± 11.2 vs. 7.1 ± 4.8 mg/L, p: 0.045) were significantly higher in Group 1, whereas albumin (3.6 ± 0.5 vs. 3.8 ± 0.6 g/dL, p: 0.047) and parathyroid hormone (355.2 ± 260.2 vs. 532.1 ± 332.9 ng/L, p: 0.015) levels were significantly lower. Peritoneal thickness was significantly correlated with duration of PD (r: 0.775, p < 0.001) and CRP (r: 0.282, p: 0.006). Regression analysis showed that peritoneal thickness (Exp (B) [95% CI]: 0.029 [0.003-0.253], p: 0.001) was independent predictor of decreased Kt/V in PD patients. In conclusion, prolonged PD duration and increased peritoneal thickness are associated with a decrease in Kt/V over time. CT may be an alternative and noninvasive method instead of peritoneal biopsy for determining the structural changes of the peritoneal membrane .

The development and structure of the mesentery.

The position of abdominal organs, and mechanisms by which these are centrally connected, are currently described in peritoneal terms. As part of the peritoneal model of abdominal anatomy, there are multiple mesenteries. Recent findings point to an alternative model in which digestive organs are connected to a single mesentery. Given that direct evidence of this is currently lacking, we investigated the development and shape of the entire mesentery. Here we confirm that, within the abdomen, there is one mesentery in which all abdominal digestive organs develop and remain connected to. We show that all abdominopelvic organs are organised into two, discrete anatomical domains, the mesenteric and non-mesenteric domain. A similar organisation occurs across a range of animal species. The findings clarify the anatomical foundation of the abdomen; at the foundation level, the abdomen comprises a visceral (i.e. mesenteric) and somatic (i.e. musculoskeletal) frame. The organisation at that level is a fundamental order that explains the positional anatomy of all abdominopelvic organs, vasculature and peritoneum. Collectively, the findings provide a novel start point from which to systemically characterise the abdomen and its contents.

Evaluation of the distance from the anterior cervicovaginal junction to the anterior peritoneal reflection for anterior colpotomy during vaginal hysterectomy in Korean women.

ABSTRACT: This study aimed to know the distance of the cervicovaginal junction (CVJ) to the anterior peritoneal reflection (APR) as measured in surgical specimens, and assess the distance between the CVJ and APR to ensure safe anterior colpotomy for vaginal hysterectomy among Korean women.Patients who underwent vaginal hysterectomy were included in the analysis. According to the presence of pelvic organ prolapse or menopausal status, the distance from the CVJ to the APR was assessed preoperatively through transvaginal ultrasonography (TV-US), as well as intraoperatively using surgical specimens. The intraclass correlation coefficient was used to determine the reliability between 2 measurements.In total, 171 patients were included. The median distance from the CVJ to the APR measured on TV-US was 19.8 (3.3-41.3) mm. Meanwhile, the median distance from the CVJ to the APR measured using the surgical specimen was 26.0 (12.0-55.0) mm. The intraclass correlation coefficient for the absolute agreement between 2 measurements was 0.353 (95% confidence interval: 0.002-0.570; P < .001), which is indicative of poor reliability. The median distance from the CVJ to the APR measured using the surgical specimen did not differ significantly between the 2 groups according to pelvic organ prolapse (26.0 [12.0-55.0] vs 27.5 [17.0-55.0] mm, P = .076] and menopausal status (27.0 [15.0-55.0] vs 26.0 [12.0-55.0] mm, P = .237).TV-US does not an accurately measure the dissection plane length from the CVJ to the APR during anterior colpotomy. During vaginal hysterectomy, the median distance from the CVJ to the APR measured using the surgical specimen was 26 (12.0-55.0) mm, which can help decrease surgical complications.

Carl Toldt Centennial, Surgeon and Anatomist.

Carl Florian Toldt was an Austrian anatomist who made meaningful contributions worldwide and defined what is one of the most important surgical landmarks in abdominal surgery. Through his research studies, the embryologic dissection plane known as the "White Line of Toldt" represents an important anatomical landmark that helps to mobilize either the ascending or descending colon. His career spanned over 45 years, beginning in Verona and continuing to Prague and Vienna. He was an author of several innovative books and scientific articles regarding micro- and macroscopic anatomy. In addition, he received numerous recognitions and prizes for his work, making him an essential figure in the medical scientific community. Even a street in Vienna, Karl-Toldt-Weg, is named in his honor. The purpose of this historical article is to celebrate and honor Toldt 100 years following his death, remembering his scientific contributions to the medical and surgical fields and giving thanks for his numerous accomplishments. This article brings light to the man behind the eponym.

Rectus abdominis muscle thickness as a predictor of peritoneal catheter dysfunction in emergency-start peritoneal dialysis patients.

BACKGROUND: Percutaneous insertion of a peritoneal dialysis catheter (PDc) is an alternative to open surgical techniques, and the anatomical characteristics of the abdominal wall may predict PDc dysfunction. We evaluated the role of rectus abdominis muscle (RAM) thickness as a predictor of PDc dysfunction. MATERIALS AND METHODS: A prospective cohort of emergency-start PD patients (EmPD) who had their first percutaneous PDc insertion were included. PDc failure was defined as the removal of a PDc due to mechanical failure within the first 30 PD fluid exchanges. Clinical variables were recorded. The skin to parietal peritoneum depth and RAM thickness were determined by abdominal ultrasound. Univariate and multivariate logistic regression models were developed to test associations between clinical parameters and PDc dysfunction. RESULTS: Over 6 months, 119 patients underwent PDc insertion; 73 (61.3%) were males, with a mean age of 46.0 ± 17.8 years. The mean skin-to-peritoneum depth was 2.5 ± 1.0 cm, the RAM thickness was 0.91 ± 0.3 cm, and catheter implantation was successful in 116 (97.4%) patients. Insertion failed in 3 (2.5%) cases, and 30 (25.8%) patients presented with catheter dysfunction. Univariate analysis indicated that RAM thickness ≥ 1.0 cm, skin-to-peritoneum depth > 2.88 cm, abdominal waist > 92.5 cm, and skin-to-RAM fascia distance > 2.3 cm were associated with PDc dysfunction; in multivariate logistic regression analysis, only greater RAM thickness remained a significant predictor (OR 1.6, 95% CI 1.38 - 1.88, p < 0.001). CONCLUSION: In EmPD patients, RAM thickness is associated with PDc dysfunction and could aid in identifying patients at risk for PDc dysfunction in emergency settings. Additional adequately powered studies are needed to confirm our findings.

Anatomical Distance From the Cervicovaginal Junction to the Uterovesical Peritoneal Reflection.

OBJECTIVE: The objective of this study was to measure the anatomical distance from the cervicovaginal junction to the uterovesical peritoneal reflection (CJ-PR). METHODS: A total of 120 hysterectomy patients were selected as study subjects. The uterus was removed, and the CJ-PR distance was immediately measured. For total vaginal hysterectomy, measurement was performed intraoperatively. The cervical length was also measured postoperatively. RESULTS: The median (interquartile) CJ-PR distance for all subjects was 3.3 (2.9-3.7) cm. Comparison of premenopausal and postmenopausal women without prolapse revealed median CJ-PR distances of 3.3 (3.0-3.6) cm and 3.0 (2.6-3.4) cm, respectively. The CJ-PR distance was longer in women with prolapse (4.6 [3.7-5.6] cm) than in those without prolapse (3.2 [2.8-3.6] cm). The median cervical lengths were 3.1 (2.7-3.6) cm for postmenopausal patients without prolapse and 4.4 (3.6-5.8) cm for postmenopausal patients with prolapse. CONCLUSIONS: Knowledge of the CJ-PR distance may help gynecologists predict how far the uterovesical PR is from the anterior vaginal incision.

Variations in Laminar Arrangements of the Mesocolon and Retropancreatic Fascia: a Histological Study Using Human Fetuses Near Term.

OBJECTIVE: The embryonic mesentery of the ascending and descending colons as well as the pancreas disappears due to peritoneal fusion, but there might be no or few photographic demonstrations of the intermediate morphologies during the process. The aims of this study were to characterize the morphological relationship of the interface between the renal fascia and peritoneum. METHODS: Fourteen late-stage fetuses with crown rump lengths (CRLs) of 250-325 mm (gestational age: 30-38 weeks) were histologically examined. RESULTS: The renal fascia, a thick or thin layer consisting of densely-distributed abundant fibers, was consistently separated from the renal capsule by a perirenal space containing fat. The transverse colon carried a typical mesocolon histologically different from the renal fascia. The ascending and descending mesocolons were irregularly divided into multiple laminae and the colic external longitudinal muscle appeared to directly contact the renal fascia. There was a spectrum of variations from multiple laminae to a single thick fascia between the pancreatic body and the left kidney or adrenal. CONCLUSIONS: A fascial development after retroperitoneal fusion of the mesentery showed great individual and site-dependent differences in proportion of 1) a complete fusion with the renal fascia and 2) a multilaminar structure including the remnant peritoneum. These variations masked the likely stage-dependent change.

Structure and surgical dissection layers of the bare area of the liver.

BACKGROUND: The bare area was reportedly formed by direct adhesion between the liver and diaphragm, meaning that the bare area lacked serosal components. This study aimed to analyze the structure of the bare area by an integrated study of surgical and laparoscopic images and pathological studies and describe surgical procedures focusing on the multilayered structure. METHODS: Several surgical specimens of hepatectomy were analyzed histologically to evaluate the macroscopic structure of the bare area. Laparoscopic images and cadaver anatomy of the bare area were also examined. RESULTS: The multilayered structure of the bare area comprised the liver, sub-serosal connective tissue, liver serosa, parietal peritoneum, retroperitoneal connective tissue, epimysium of the diaphragm, and diaphragm, in order from the liver to the diaphragm. The liver serosa and the parietal peritoneum fused with each other. This multilayered structure of the bare area is observed almost constantly. There are two layers in the dissection of the bare area in surgical procedures, an outer layer of the fused peritoneum (near the diaphragm) and an inner layer of the fused peritoneum (near the liver). Laparoscopic images enabled us to recognize the multilayered structure of the bare area. CONCLUSIONS: Histopathological findings showed the bare area to be a multilayered structure. In cases where tumors are located underneath the bare area, it could be important to dissect the bare area, with careful attention to its multilayered structure. Surgical dissection of the bare area in the outer layer of the fused peritoneum could allow a sufficient safety margin.

The Peritoneum: What Nuclear Radiologists Need to Know.

The peritoneum is the largest and most complex serous membrane in the human body. The peritoneal membrane is composed of a layer of mesothelium supported by a thin layer of connective tissue. The peritoneum is one continuous sheet, forming two layers and a potential space between them - the peritoneal cavity- which is subdivided into multiple communicating spaces containing small amount of serous fluid that facilitates frictionless movement of mobile intraabdominal viscera. Peritoneum also contributes to fluid exchange mechanism and plays a role in immune response. The peritoneum is subject to many neoplastic and non-neoplastic processes including infections, trauma, developmental and inflammatory processes. Different Nuclear Medicine imaging techniques can be used to diagnose peritoneal diseases, most of these techniques can be customized depending on the clinical scenario and expected findings. Peritoneal scintigraphy can detect abnormal peritoneal communication or compartmentalization. Several nuclear medicine techniques can help characterize intraperitoneal fluid collections and differentiate sterile from infected fluid. PET imaging plays an important role in imaging of different neoplastic and non-neoplastic peritoneal pathologies. Nuclear radiologists need to be familiar with peritoneal anatomy and pathology to interpret peritoneal findings in dedicated peritoneal nuclear medicine imaging studies, as part of more general nuclear medicine scans, or on CT or MRI component of hybrid imaging studies. The purpose of this article is to review the normal peritoneal anatomy, various pathologic processes involving the peritoneum, and different nuclear medicine and hybrid imaging techniques that can help detect, characterize, and follow up peritoneal pathology.

[Rise and mix of membrane anatomy].

Membrane anatomy is the anatomy of mesentery in broad sense and its beds, which was merged from clinical results of surgical practice, optic observation and traditional theories contradiction or omission. Membrane anatomy is not only a plane, but also a body or bloc which is surrounded by fascia and serous membrane. It is not only fascia, but also a channel or pathway, in which the life event occurred. It is not only mesentery anatomy, but included mesentery beds, on which the mesentery was lied, even buried in. Following the new version of this anatomy map, surgical hazard during operation and postoperative oncological recurrence will be decreased simultaneously. And, following the definition of the mesentery in broad sense, new mesenteries will be discovered under macro surgery, which will optimize surgical operation and get better surgical and oncological results.

[Are various theoretical models of membrane anatomy mutually exclusive or inclusive?]

The theory of membrane anatomy is now widely accepted due to the observation of fine anatomical structure with the help of laparoscopic magnifying effect. From the perspective of systematic anatomy, the mesentery is considered as an integral organ in the theory of mesenteric anatomy. Interfascial anatomy belongs to regional anatomy, which focuses on the guiding significance of fascial space for operation. The theory of membrane anatomy belongs to surgical anatomy or applied anatomy, which emphasizes the anatomy of membrane and mesangial bed, and reveals the existence of 'metastasis V' in the mesentery. It is considered that the essence of membrane anatomy operation is to prevent cancer leakage. Various theories of membrane anatomy seek common ground while reserving differences, complement each other, and upgrade iteratively. They help to explain the structure and function of membrane from different perspectives and they are of great benefit to improve the quality of operations. Thus, they should be treated in an eclectic manner.

[Concept of membrane anatomy in laparoscopic sleeve gastrectomy procedure].

Membrane anatomy refers to the fascia and/or serosa enveloping the organs and their blood vessels and hanging on the posterior wall of the body cavity, which emphasizes the entirety and integrity of the membrane during operation. The concept can also be applied to most surgical operations. This article mainly expounds the application of the concept of membrane anatomy in the process of laparoscopic sleeve gastrectomy, which is embodied in the key steps of separating the greater omentum, mobilizing the fundus, mobilizing the posterior wall of the stomach, cutting the greater curvature of the stomach, reinforcing the staple line of the stomach, and suturing the greater omentum with staple line, in order to make the laparoscopic sleeve gastrectomy more accurate and precise with less bleeding, fewer complications and faster postoperative recovery.

[Total mesorectal excision with preservation of Denonvilliers' fascia (iTME) based on membrane anatomy].

Total mesorectal excision (TME) has been advocated as the golden standard of mid-low rectal cancer surgery for nearly 30 years. However, the complication of postoperative urinary and sexual dysfunctions due to intraoperative nerve injury has yet to be improved. Based on the concept of membrane anatomy, we carried out a systematic study on the important membrane anatomical structure anterior to the rectum--Denonvilliers' fascia. From multiple aspects including anatomy, physiology, histochemistry and surgical practice, we verified the importance of Denonvilliers' fascia for TME surgery in prevention of intraoperative nerve injury and postoperative urogenital dysfunction. Moreover, based on anatomical study of the surgical marker line of Denonvilliers' fascia (Wei's line) and surgical plane, we proved that total mesorectal excision with preservation of Denonvilliers' fascia (iTME) was feasible and practical. Therefore, we conducted a large multicentric randomized controlled trial (RCT). The mid-term result demonstrated that compared with traditional TME surgery, iTME was more effective in reducing the incidence of postoperative urinary and sexual dysfunctions in male patients with mid-low rectal cancer, without sacrifice of short-term tumor radical outcome. We believe that the final RCT result of iTME, based on membrane anatomy, will provide solid evidence for the update of concepts of rectal cancer surgery.

[Better understanding of interfacial planes in colorectal cancer surgery and the value of small vessels on fascia in the identification of interfacial planes].

The introduction of total mesorectal excision and wider use of laparoscopic surgery pushed the field of colorectal surgery into an era of interfasical dissection. The Japanese suggestion of fascial arrangement of the trunk in a multilaminar, symmetrical and parallel way helps in better understanding of fascial relationship and interfascial planes surrounding the colon and the rectum. However, different interpretations of the multilayer retroperitoneal fascial relationship, complexity of fascial structures within the pelvis and dense adhesion between two apposed fasciae at special points make it still challenging for the surgeon to decide on the precise interfascial plane for colorectal mobilization. Small vessels on fasica propria of the rectum and various retroperitoneal fascia, especially ureterohypogastric fascia show distinctive features. The root of small vessels on fascia propria of the rectum helps to identify the anterolateral and posterolateral interfascial plane in the middle and low rectum. The longitudinal trajectory of small vessel on ureterohypogastric fascia and scarcity interfascial vascular communication between mesocolic and retroperitoneal fascia help the surgeon to find and stay in the interfacial plane during colorectal mobilization. More knowledge of fascial and interfascial plane will certainly help achieve better mesocolic mesorectal integrity and reduce the risk of injuries to autonomic nerves. More anatomical, histological and embryological studies are warranted with respect to relationship between small vessels and fasciae.

[Effects of sleeve gastrectomy base on "membrane anatomy" concept on postoperative nausea and vomiting in patients with obesity or metabolic diseases].

Objective: To explore the effects of the application of membrane anatomy concept in sleeve gastrectomy on postoperative nausea and vomiting (PONV) in patients with obesity or metabolic diseases. Methods: A retrospective cohort study was conducted. Clinical data of 88 patients with obesity or metabolic diseases who underwent laparoscopic sleeve gastrectomy in The First Affiliated Hospital of Jinan University from September 2018 to June 2019 were retrospectively analyzed. Forty patients underwent sleeve gastrectomy with membrane anatomy concept as membrane anatomy group, and the other 48 patients underwent traditional sleeve gastrectomy as traditional operation group. There were no significant differences in baseline data between the two groups (all P>0.05). The PONV score of and the times of antiemetic drugs used during 0-6 h and 6-24 h after operation were compared between the two groups. Higher PONV represents more serious nause and vomiting, the score ≥5 is defined as clinical significant PONV. Results: All patients of the two groups successfully completed the operation, and there was no conversion to open, reoperation, and operation-related death. The intraoperative blood loss in the membrane anatomy group was significantly less than that in the traditional surgery group [median: 5.0 (5.0, 5.8) ml vs. 10.0 (5.0, 10.0) ml, Z=-3.265, P=0.001]. There were no significant differences between the two groups in terms of operative time, postoperative hospital stay, gastroesophageal reflux, pain score and postoperative complications (all P>0.05). There was no postoperative bleeding or gastric leakage in either groups. There were no significant differences in PONV score, incidence of clinically significant PONV and use of antiemetics 0-6 h after operation between two groups (all P>0.05). From 6 to 24 hours after operation, compared with traditional surgery group, the membrane anatomy group had lower PONV score (4.6±0.9 vs. 5.1±0.7, t=-2.192, P=0.007), lower incidence of clinically significant PONV [55.0% (22/40) vs. 83.3% (40/48), χ(2)=8.414, P=0.004] and less use of antiemetics [3 times: 10.0% (4/40) vs. 27.1% (13/48), Z=-2.880, P=0.004]. Postoperative follow-up ranged from 1 to 6 months (median 3), 32 cases in membranous anatomy group and 38 cases in the traditional operation group were followed up. One case in the traditional operation group received symptomatic treatment in the local hospital due to functional intestinal obstruction 1 month after surgery and was discharged after recovery. The remaining patients had no postoperative complications and were not readmitted to hospital. Conclusion: Sleeve gastrectomy based on membrane anatomy in the treatment of patients with obesity or metabolic syndrome can make surgical procedure more precise and meticulous, reduce the intraoperative bleeding and the incidence of PONV.