[Intraoperative anatomical observation of mesentery morphology of colonic splenic flexure].

Objective: At present, surgeons do not know enough about the mesenteric morphology of the colonic splenic flexure, resulting in many problems in the complete mesenteric resection of cancer around the splenic flexure. In this study, the morphology of the mesentery during the mobilization of the colonic splenic flexure was continuously observed in vivo, and from the embryological point of view, the unique mesenteric morphology of the colonic splenic flexure was reconstructed in three dimensions to help surgeons further understand the mesangial structure of the region. Methods: A total of 9 patients with left colon cancer who underwent laparoscopic radical resection with splenic flexure mobilization by the same group of surgeons in Union Hospital of Fujian Medical University from January 2018 to June 2019 were enrolled. The splenic flexure was mobilized using a "three-way approach" strategy based on a middle-lateral approach. During the process of splenic flexure mobilization, the morphology of the transverse mesocolon and descending mesocolon were observed and reconstructed from the embryological point of view. The lower margin of the pancreas was set as the axis, and 4 pictures for each patient (section 1-section 4) were taken during middle-lateral mobilization. Results: The median operation time of the splenic flexure mobilization procedure was 31 (12-55) minutes, and the median bleeding volume was 5 (2-30) ml. One patient suffered from lower splenic vessel injury during the operation and the bleeding was stopped successfully after hemostasis with an ultrasound scalpel. The transverse mesocolon root was observed in all 9 (100%) patients, locating under pancreas, whose inner side was more obvious and tough, and the structure gradually disappeared in the tail of the pancreatic body, replaced by smooth inter-transitional mesocolon and dorsal lobes of the descending colon. The mesenteric morphology of the splenic flexure was reconstructed by intraoperative observation. The transverse mesocolon was continuous with a fan-shaped descending mesocolon. During the embryonic stage, the medial part (section 1-section 2) of the transverse mesocolon and the descending mesocolon were pulled and folded by the superior mesenteric artery (SMA). Then, the transverse mesocolon root was formed by compression of the pancreas on the folding area of the transverse mesocolon and the descending mesocolon. The lateral side of the transverse mesocolon root (section 3-section 4) was distant from the mechanical traction of the SMA, and the corresponding folding area was not compressed by the tail of the pancreas. The posterior mesangial lobe of the transverse mesocolon and the descending mesocolon were continuous with each other, forming a smooth lobe. This smooth lobe laid flat on the corresponding membrane bed composed of the tail of pancreas, Gerota's fascia and inferior pole of the spleen. Conclusions: From an embryological point of view, this study reconstructs the mesenteric morphology of the splenic flexure and proposes a transverse mesocolon root structure that can be observed consistently intraopertively. Cutting the transverse mesocolon root at the level of Gerota's fascia can ensure the complete resection of the mesentery of the transverse colon.

A video guide of five access methods to the splenic flexure: the concept of the splenic flexure box.

AIM: The aim of this study was to describe all the possible approaches for laparoscopic splenic flexure mobilization (SFM), each suitable for specific situations, and create an illustrated system to show SFM approaches in an easy and practical way to make it easy to learn and teach. METHODS: Two different phases. First part: Cadaver-based study of the colonic splenic flexure anatomy. In order to demonstrate the different approaches, a balloon was placed through the colonic hepatic flexure in the lesser sac without sectioning any of the fixing ligaments of the splenic flexure. Second part: A real case series of laparoscopic SFM. RESULTS: First part: 11 cadavers were dissected. Five potential approaches to SFM were found: anterior, trans-omentum, lateral, medial infra-mesocolic, and medial trans-mesocolic. The illustrative system developed was named: Splenic Flexure "Box"(SFBox). Second part: One of the types of SFM described in first part was used in five patients with colorectal cancer. Each laparoscopic approach to the splenic flexure was illustrated in a video accompanied by illustration aids delineating the access. CONCLUSION: With the cadaver dissection and subsequent demonstration in real-life laparoscopic surgery, we have shown five types of laparoscopic splenic flexure mobilization. The Splenic Flexure "Box" is a useful way to learn and teach this surgical maneuver.

Standardize the Surgical Technique and Clarify the Relevant Anatomic Concept for Complete Mobilization of Colonic Splenic Flexure Using da Vinci Xi® Robotic System.

BACKGROUND: The present study is to set up a standardized approach for complete mobilization of colonic splenic flexure using da Vinci Xi® robotic system, based on clarification of the mesenteric structures of distal transverse colon. METHODS: The surgical outcomes and relevant anatomic structures of 104 consecutive patients undergoing robotic resection of primary colorectal cancer with the intent of complete mobilization of colonic splenic flexure using da Vinci Xi® robotic system were retrospectively reviewed. RESULTS: Complete mobilization of colonic splenic flexure can be efficiently performed by the Xi® robotic system, as demonstrated by short operation time, minimal intra-operative blood loss, and few surgical complications. Xi® robotic system has overcome the drawbacks of Si® robotic system for the mobilization of colonic splenic flexure. The present study defined the following anatomic hallmarks for the colonic splenic flexure: (1) The transverse mesocolon distal to the inferior mesenteric vein adheres to the low border of pancreas by the avascular fibrous connective tissues, which have been inappropriately named as "mesenteric root"; (2) The colonic splenic flexure abuts closely to spleen with an acute angle in 78.85% (n = 82/104); (3) Only a minority of patients presented with the Riolan branch (15.38%, n = 16/104) or the Moskowitz artery (8.65%, n = 9/104). CONCLUSION: With increased maneuverability of Xi® robotic arms and the clarification of relevant anatomic concept, the surgical technique for the complete mobilization of colonic splenic flexure can be standardized; and the standardization of surgical technique is the first step toward the enhanced automation in the rapidly evolving robotic systems.

Lymphatic Drainage of the Splenic Flexure Defined by Intraoperative Scintigraphic Mapping.

BACKGROUND: The optimal surgical management of splenic flexure cancer is debated, partly because of an incomplete understanding of the lymphatic drainage of this region. OBJECTIVE: This study aimed to evaluate the normal lymphatic drainage of the human splenic flexure using laparoscopic scintigraphic mapping. DESIGN: This was a clinical trial. SETTINGS: The study was conducted at a single tertiary care center. PATIENTS: Thirty consecutive patients undergoing elective colorectal resections without splenic flexure pathology were recruited. INTERVENTION: Technetium-99m was injected subserosally at the splenic flexure. MAIN OUTCOME MEASURES: Lymphatic scintigraphic mapping was undertaken at 15, 30, and 60 minutes using a laparoscopic gamma probe at the left branch of the middle colic, left colic, inferior mesenteric, and ileocolic (control) lymphovascular pedicles. RESULTS: Lymphatic drainage at 60 minutes was strongly dominant in the direction of the left colic pedicle (96% of patients), with a median gamma count of 284 (interquartile range, 113-413), versus the left branch of the middle colic count of 31 (interquartile range, 15-49; p < 0.0001). This equated to a median 9.2-times greater flow to the left colic versus the middle colic. Counts at the left colic were greater than all of the other mapped sites at 15, 30, and 60 minutes (p < 0.001), whereas middle colic and inferior mesenteric artery counts were equivalent. The protocol increased operative duration by 20 to 30 minutes without complications. LIMITATIONS: These results report lymphatic drainage from patients with normal splenic flexures, and caution is necessary when extrapolating to patients with splenic flexure cancers. CONCLUSIONS: The lymphatic drainage of the normal splenic flexure is preferentially directed toward the left colic in the high majority of cases. Retrieving these nodes should be prioritized in splenic flexure cancer resections, with important secondary emphasis on left middle colic nodes, supporting segmental (left hemicolectomy) resection as the procedure of choice. Additional development of colonic sentinel node mapping using these techniques may contribute to individualized surgical therapy morbidity. See Video Abstract at http://links.lww.com/DCR/A495.

Anatomical and embryological perspectives in laparoscopic complete mesocoloic excision of splenic flexure cancers.

BACKGROUND: Laparoscopic complete mesocoloic excision (CME) with central vascular ligation for splenic flexure cancer is technically challenging because of its anatomical complexity. Although embryological and anatomical consideration should be helpful to perform CME in colorectal cancer surgery, such studies on the splenic flexure are lacking. METHODS: The splenic flexure is located embryologically between the terminal portion of the midgut and the beginning of the hindgut, and is supplied by the superior mesenteric and inferior mesenteric arteries. The mesentery of the transverse and descending colon originally is a continuous sheet, although they rotate and partially fuse to each other during development. Our surgical strategy was excision of the transverse and descending mesocolon with ligation of the left colic artery and left branch of the middle colic artery, and extraction of the specimen in an intact package wrapped by the embryological planes. RESULTS: We performed laparoscopic surgery according to our surgical strategy in 17 patients with splenic flexure colon cancer. There were no conversions to open surgery or serious intraoperative complications. Two patients had pathological stage (pStage) I, 5 pStage II, 9 pStage III, and 1 pStage IV disease. No patient had recurrence except for 1 with pStage IV cancer, with a median follow-up of 16 months. CONCLUSIONS: Our laparoscopic CME technique is feasible for treatment of splenic flexure cancer. Knowledge of anatomy based on embryology is essential to perform this surgery.

The length of the large intestine in children determined by computed tomography scan.

Little information is available on the length of the normal large intestine and its component parts in children. This information would be useful for procedures such as colonoscopy. The aim of this study was to investigate the length of the large intestine and its component parts in New Zealand children. Archival deidentified pediatric supine abdominopelvic computed tomography (CT) scans were retrospectively analyzed. After exclusion criteria, a total of 112 scans (57 males and 55 females) were included in the study and divided into three age groups: 0-2 years (n = 33), 4-6 years (n = 40), and 9-11 years of age (n = 39). The length of the large bowel increased from a mean of 52 cm in children aged <2 years to 73 cm at 4-6 years and 95 cm at 9-11 years. In all age groups, the transverse colon was the longest segment, contributing ∼30% of the total length of the large bowel. In comparison to total large bowel length, the mean proportional length of the rectum (9-12%), sigmoid colon (23-27%), descending colon (19-22%), transverse colon (27-32%), and ascending colon (14-17%) varied little between the three age groups. There were no significant differences between males and females in all age groups. The cecum was located in the right upper quadrant in 27% of children aged 0-2 years but in the right lower quadrant in all 9-11 year olds. These data provide useful information on the length of the large intestine and its component parts in living children, which are particularly relevant to pediatric colonoscopy and surgery. Clin. Anat. 30:887-893, 2017. © 2017 Wiley Periodicals, Inc.

Anatomical siting of the splenic flexure using computed tomography.

INTRODUCTION Often, left-sided colorectal surgery requires splenic flexure mobilisation (SFM) to allow a tension-free anastomosis to be carried out. This step is difficult and not without risk. We investigated a system of anatomical siting of the splenic flexure using computed tomography (CT). METHODS The Shrewsbury Splenic Flexure Siting (SSFS) system involves siting of the splenic flexure using the vertebral level (VL) as a reference point. We asked three surgical registrars (SRs) to analyse 20 CT scans of patients undergoing colonic resection to ascertain the anatomical site of the splenic flexure using the SSFS system. The distance from the centre of the vertebral body to the lateral edge (CVBL) of the splenic flexure was measured, as was the distance from the centre of the vertebral body to the inner abdominal wall (CVBI) along the same line, on axial images. RESULTS VL assessment demonstrated substantial inter-observer agreement with a kappa (κ) value of 0.742 (95% confidence interval (CI), 0.463-0.890). CVBL and CVBI demonstrated very strong inter-observer agreement (CVBL: κ = 0.905 (95% CI, 0.785-0.961); CVBI: 0.951 (0.890-0.979) (p<0.001). Overall, there was strong correlation between assessments by all three SRs across the three variables measured. CONCLUSIONS The SSFS system is an accurate method to site the splenic flexure anatomically using CT. We can use the SSFS system to develop a validated scoring system to help colorectal surgeons assess the difficulty of SFM.

Quantitative morphometric analysis of the myenteric nervous plexus ganglion structures along the human digestive tract.

BACKGROUND/AIM: All the functions of the digestive system are controlled, guided and initiated by the autonomic nervous system. A special part of this system placed in the wall of the gastrointestinal tract is known as the enteric or metasympathetic nervous system. The aim of this study was to analyse myenteric nervous plexus in different parts of the digestive tract. METHODS: We examined the myenteric nervous plexus of the esophagus, stomach, duodenum, jejunum, ileum, transverse colon and rectum in tissue samples taken from 30 cadavers of persons aged 20-84 years. After standard histological processing sections were stained with hematoxylin-eosin, cresyl violet (CV) and AgNO3 method. Multipurpose test system M42 was used in morphometric analysis. The results were analyzed by t-test and analysis of variance. RESULTS: The number of neurons per cm² surface was the lowest in the esophagus (2.045 ± 310.30) and the largest in the duodenum (65,511 ± 5,639). The statistical processing showed significant differences (P < 0.001) in the number of neurons between the esophagus and all other parts of the digestive tract. The maximal value of the average surface of the myenteric nervous plexus neurons was observed in the esophagus (588.93 ± 30.45 µm²) and the lowest in the stomach (296.46 ± 22.53 µm²). CONCLUSION: There are differences in the number of ganglion cells among different parts of the human digestive tract. The differences range from a few to several tens of thousands of neuron/cm2. The myenteric nervous plexus of the esophagus was characterized by a significantly smaller number of neurons but their bodies and nuclei are significantly larger compared to other parts of the digestive tract.

CT Scan Mapping of Splenic Flexure in Relation to Spleen and its Clinical Implications.

Splenic flexure mobilization is a challenging step during left colon resection. The maneuver places the spleen at risk for injury. To minimize this risk, we conducted this study for CT scan mapping of splenic flexure in relation to the spleen. One hundred and sixty CT scans of abdomen were reviewed. The level of the splenic flexure was determined in relation to hilum and lower pole of spleen. These levels were compared with patient demographics. Statistical analysis was performed using Fisher's exact test. The splenic flexure was above the hilum of the spleen in 95 patients (67.86%), at the splenic hilum level in 11 patents (7.88%), between the hilum and lower pole of the spleen in 12 (8.57%), at the lower pole of the spleen in 15 (10.7%) patients and 7 (5%) patients has a splenic flexure that lied below the lower pole of the spleen. Patient demographics showed no statistical significance in regard to splenic flexure location. Splenic flexure lies above the hilum of the spleen in majority of patients. This should be considered as part of operative strategies for left colon resection.

Mechanical characterization of human gastrocolic ligament until failure.

Road accidents can lead to abdominal injuries ranging from severe to lethal, that include hemorrhage of organs and their attachment system. A good understanding and prediction of abdominal injuries therefore requires investigation of the mechanical properties of the attachment systems of abdominal organs. In particular, the gastrocolic ligament (GCL) is one major link between the stomach and the transverse colon. This study aims to investigate the mechanical properties of the GCL under very low and high strain rate uniaxial tensile tests until failure. Thirty-five GCL samples were dissected from 7 embalmed cadavers and tested at a rate of 1 mm/s and 1 m/s. Incidence of freezing was also evaluated. The mechanical response of GCL samples showed an approximately bilinear curve. Within the first linear region (less than 5% of ligament strain), the apparent elastic modulus was estimated at 247±144 kPa, while in the second region, it was estimated at 690±282 kPa. The average failure stress (σfail) and failure strain (εfail) were 131.6±50 kPa and 29%±8%, respectively. High strain rate loading also showed high sensitivity to strain rate. The estimated GCL mechanical properties in this study can be implemented in finite element models of the abdomen to further investigate the mechanical contribution of the organ attachment system under traumatic loading conditions.

Dynamic article: surgical anatomical planes for complete mesocolic excision and applied vascular anatomy of the right colon.

BACKGROUND: Lower local recurrence rates and better overall survival are associated with complete mesocolic excision with central vascular ligation for treatment of colon cancer. To accomplish this, surgeons need to pay special attention to the surgical anatomical planes and vascular anatomy of the colon. However, surgical education in this area has been neglected. OBJECTIVE: The aim of this study is to define the correct surgical anatomical planes for complete mesocolic excision with central vascular ligation and to demonstrate the correct dissection technique for protecting anatomical structures. DESIGN AND SETTINGS: Macroscopic and microscopic surgical dissections were performed on 12 cadavers in the anatomy laboratory and on autopsy specimens. The dissections were recorded as video clips. METHODS: Dissections were performed in accordance with the complete mesocolic excision technique on 10 male and 2 female cadavers. Vascular structures, autonomic nerves, and related fascias were shown. Within each step of the surgical procedure, important anatomical structures were displayed on still images captured from videos by animations. RESULTS: Three crucial steps for complete mesocolic excision with central vascular ligation are demonstrated on the cadavers: 1) full mobilization of the superior mesenteric root following the embryological planes between the visceral and the parietal fascias; 2) mobilization of the mesocolon from the duodenum and the pancreas and identification of vascular structures, especially the veins around the pancreas; and 3) central vascular ligation of the colonic vessels at their origin, taking into account the vascular variations within the mesocolonic vessels and the autonomic nerves around the superior mesenteric artery. LIMITATIONS: The limitation of this study was the number of the cadavers used. CONCLUSIONS: Successful complete mesocolic excision with central vascular ligation depends on an accurate knowledge of the surgical anatomical planes and the vascular anatomy of the colon.

[Anatomy of splenic flexure and surgical treatment in 52 patients with non-obstructive splenic flexure colon cancer].

OBJECTIVE: To investigate the anatomic characteristics of splenic flexure, surgical techniques, and oncologic outcomes in 52 patients with non-obstructive splenic flexure colon cancer. METHODS: Clinical data of 52 patients with non-obstructive splenic flexure colon cancer from March 2004 to March 2011 in the Department of General Surgery at the Henan Province Tumor Hospital were analyzed retrospectively. RESULTS: There were 37 patients of regular type, 5 of mobile type, and 10 of adhesive type. All the patients received radical operation. Eighteen patients received pre-small intestine anastomosis, including 12 cases with regular type, 4 with mobile type, and 2 with adhesive type. The difference in pre-small intestine anastomosis among the three types was not statistically significant(P=0.062). In addition, 32 cases received retro-ileum anastomosis. There were no significant differences in operative time, intraoperative blood loss, number of lymph node dissection and positive lymph node, and postoperation complication rate among the three types. Follow up was available in all the cases. Five-year survival rates of cases with regular type, mobile type and adhesive type were 62.5%, 59.2% and 58.7% respectively(P>0.05). CONCLUSIONS: Radical resection can provide satisfactory survival for splenic flexure colon cancer patients. The anatomy of splenic flexure does not affect the type of anastomosis. Retro-ileum anastomosis is a simple and effective method for reconstruction after radical resection of the tumor.

[Effects of splenic flexure and sigmoid colon variation on the types of anastomosis after left colectomy].

OBJECTIVE: To explore the effects of splenic flexure and sigmoid colon variation on anastomosis after left colectomy. METHODS: The clinical data of 76 descending colon patients were collected retrospectively from March 2004 to April 2011 at our hospital. Statistical analysis was performed for the types of splenic flexure and sigmoid colon with regards to the choice of anastomosis. RESULTS: There were mesenteric type (n = 55), mobile type (n = 7) and adhesive type (n = 14) for splenic flexure. And among 61 regular types, 15 were of variable type for sigmoid colon variation. There was significant difference of anastomosis between the types of sigmoid colon variation [43 (78.2%) vs 5 (71.4%) vs 9 (64.3%), P > 0.05] while no significant difference existed between the types of splenic flexure [I type 56(91.8%) vs II type 1 (14.3%), III or IV type 0, P < 0.05]. CONCLUSION: A clinician should pay more attention to the types of sigmoid colon variation. And it helps to select the right approach of anastomosis after left colectomy.

Two colons-two cancers: paradigm shift and clinical implications.

Embryological and physiological data suggest that proximal (in relation to the splenic flexure) and distal parts of the colon represent distinct anatomical and functional entities. Since 1990, molecular biologists have identified two distinct pathways, microsatellite instability (MSI) and chromosomal instability (CIN), which are involved in the pathogenesis of colon cancer (CC). Thus, a new paradigm has emerged with the discovery that CC is a heterogeneous disease; furthermore recent data have demonstrated that these two distinct pathways in colorectal carcinogenesis are characterized by a different clinical outcome. The implications for the clinicians are twofold; (1) tumors originating from the proximal colon have a better prognosis due to a high percentage of MSI-positive lesions; and (2) location of the neoplasm in reference to the splenic flexure should be documented before group stratification in ongoing trials of adjuvant chemotherapy for CC. In the future, clinical decision-making regarding adjuvant chemotherapy might be stratified according to the MSI status of cancers located proximally to the splenic flexure.

Sympathovagal balance fluctuates during colonoscopy.

BACKGROUND AND STUDY AIM: Colonoscopy is a common gastroenterological procedure for investigation of the bowel. The main side effects of colonoscopy are pain during investigation, cardiovascular complications and very rarely even death. The aim of this study was to compare the continuous fluctuation of heart rate variability (HRV) components during colonoscopy under normal conditions, analgesia/sedation, and total intravenous anesthesia. PATIENTS AND METHODS: 37 consecutive patients (aged 35 - 65), were randomly allocated to three groups: no sedation (control group 1); analgesia/sedation (group 2); and total intravenous anesthesia (group 3). Holter electrocardiography and subsequent frequency domain analysis were undertaken. The low-frequency (LF, 0.04 - 0.15 Hz) and the high-frequency (HF, 0.15 - 0.40 Hz) components were estimated using spectral analysis in the usual way. Normalized units (nu) were calculated from the following equations: LFnu = LF/(LF + HF), and HFnu = HF/(LF + HF). RESULTS: Groups 2 and 3 were found to have a significantly lower HFnu and higher LFnu than group 1 essentially throughout the procedure. A one-way analysis of variance and t-test confirmed that the differences were significant when the colonoscope reached the splenic flexure as were the LF/HF balances at the splenic and hepatic flexures and the cecum. The percentage change in LF/HF was also analyzed, and it was found that in group 3 the mean change was over 136 % when the colonoscope reached the sigmoid flexure, which was significantly higher than in the other two groups. CONCLUSION: Most changes in HRV components occurred during colonoscopy of the left side of the bowel. Analgesia/sedation and total intravenous anesthesia increased HRV by increasing the LF component.