Terminology and nomenclature in colonic surgery: universal application of a rule-based approach derived from updates on mesenteric anatomy

Peritonectomy and resection of mesentery during Visceral-Peritoneal Debulking (VPD) in patients with stage IIIC-IV ovarian cancer: A phase I-II trial

OBJECTIVE

To describe the surgical technique, assess feasibility, efficacy, and safety of peritonectomy and/or resection of mesentery (P-Rme) during Visceral-Peritoneal Debulking (VPD) in patients with stage IIIC-IV ovarian cancer (OC).

METHODS

In April 2009 we registered a protocol study on the safety and feasibility of P-Rme. In the period April 2009-December 2022, 687 patients with FIGO stage IIIC-IV ovarian cancer underwent VPD. One hundred and twenty-nine patients (18.7%) had extensive disease on the mesentery and underwent P-Rme. Feasibility was assessed as the number of procedures completed. Efficacy was measured as the rate of Complete Resection (CR). Safety was defined by the intra- and post-operative morbidity rate specifically associated with these procedures.

RESULTS

In all patients P-Rme was successfully completed. P-me was performed in 82 patients and R-me in 47, both procedures in 23 patients. CR was achieved in all 129 patients with an efficacy of 100%. Intra-operatively 5 patients out of 129 experienced small bowel loop surgical devascularization. They required small bowel resection and anastomosis. The procedure specific morbidity was 3.8%. No post-operative complication was related to P-Rme. At 64 months median follow-up, survival outcomes in the study group were similar to patients in the control group.

CONCLUSION

Overall, almost 20% of the VPD patients needed P-Rme to obtain a CR. P-Rme was a safe and effective step during VPD. The rate of CR in the study group was 100% achieved thanks to the addition of the P-Rme. No procedure specific post-operative complications occurred but 3.8% of the patients had unplanned additional surgery related to these procedures.

piRNA-18 Inhibition Cell Proliferation, Migration and Invasion in Colorectal Cancer

Colorectal cancer is one of the most prevalent malignancies worldwide. Evidences indicate that piRNA-18 are closely involved and contributed to tumorigenesis and cancer progression. Therefore, it is very necessary to investigate the effects of piRNA-18 on the proliferation, migration, and invasiveness of colorectal cancer cells, so as to provide theoretical basis for finding new biomarkers and accurate diagnosis and treatment of colorectal cancer. Here, Five pairs of colorectal cancer tissue samples and their corresponding adjacent samples were analyzed by real-time immunofluorescence quantitative PCR and the difference in piRNA-18 expression among colorectal cancer cell lines was further verified. MTT assay were used to study the changes in the proliferation of colorectal cancer cell lines after piRNA-18 overexpression. Wound-healing assay and Transwell assay were used to study the changes in migration and invasion. Flow cytometry were used to study the changes in apoptosis and cycle. SC inoculation of colorectal cancer cell lines into nude mice were used to observe the effect in the proliferation. piRNA-18 was lowlier expressed than adjacent tissues and normal intestinal mucosal epithelial cells in colorectal cancer and colorectal cancer cell line. After overexpression of piRNA-18, cell proliferation and migration as well as invasiveness in SW480 and LOVO cells decreased. The cell lines with piRNA-18 overexpression had obvious G1/S phase arrest in cell cycle, and the weight and volume of subcutaneously transplanted tumors are decreased. Our findings highlighted that piRNA-18 may play an inhibitory role in colorectal cancer.

"Flexures and bends of the large intestine: Current terminology and a suggestion to simplify it"

There are a number of inconsistencies in the description of the bends of the colon down to the anus. This is historically based on the fact that anatomists saw the colon in its position in the abdominal cavity down to the pelvis and thus from the "outside" and also described it in this way. This view is still useful in clinical practice today (e.g. for the abdominal surgeons). For the greater part of clinicians, however, the view has shifted due to modern endoscopy. This allows examiners to see the terminal section of the intestine and the colon from the "inside". To accommodate both "ways of looking" in terms of modern medicine, we have been guided by today's clinical needs, and here we attempt to reconcile these with the historically evolved anatomical terms to create a nomenclature that meets all the needs of students, anatomists and clinicians looking at the large intestine from the inside and outside. With this in mind, we propose to speak of colic flexures (right colic flexure = RCF = hepatic flexure, flexura coli sinistra; left colic flexure = LCF = splenic flexure, flexura coli dextra; descending-sigmoid flexure = DSF; sigmoid-rectum flexure = SRF) for the colon (colon). For the rectum (rectum), we suggest the term bend (superior, intermediate and inferior) when viewed in the frontal plane, the term curvature (sacral curvature; anorectal curvature = perineal curvature) when viewed in the sagittal plane.

There is no fusion fascia in the abdomen and extraperitoneal fascia always surrounds the mesentery

Toldt's fascia has always been described as a fusion fascia formed by two layers of visceral peritoneum when the mesentery attaches to the posterior abdominal wall. However, there is still no consensus about the mesentery and its surrounding fascia based on the current anatomic theories. This study aimed to determine the anatomical structures of the abdomen and provide a correct surgical plane for mesenteric-based surgery. Surgical videos of 121 patients who underwent laparoscopic operations of the digestive tract were reviewed to identify and compare the anatomical structures of the mesentery and associated fascia. Twenty-one postoperative specimens were stained with hematoxylin and eosin to indicate the histological appearance of the mesentery and its surrounding fascia. Furthermore, dynamic models had been established to explain the formation mechanism of the associated histological structures in different regions during the progression of mesenteric attachment. The fasciae surrounding the mesentery, including the submesothelial connective tissue, the subserosal connective tissue, Toldt's fascia, and "angel hair," have the same histological characteristic to extraperitoneal fascia. The general anatomical structure of the abdomen can be divided into three layers (abdominal wall, urogenital system, and digestive system) and two interlayers (transversalis fascia and extraperitoneal fascia). The extraperitoneal fascia surrounds the entire digestive system and is the natural layer separating adjacent structures from each other. Typical histological structures in the regions of posterior attachment include the fascia propria of the mesentery, mesofascial plane, extraperitoneal fascia, retrofascial plane, and anterior renal fascia. The urogenital system is surrounded by similar histological structures. There is no fusion fascia in the abdomen due to retreat of the visceral peritoneum, and all of the fasciae surrounding the mesentery are extraperitoneal fascia. This study demonstrates that the typical histological structures in the regions of attachment and mesofascial plane are the correct anatomic interface for mesenteric-based surgery.

Radiology of the Mesentery

The recent description and re-classification of the mesentery as an organ prompted renewed interest in its role in physiological and pathological processes. With an improved understanding of its anatomy, accurately and reliably assessing the mesentery with non-invasive radiological investigation becomes more feasible. Multi-detector computed tomography is the main radiological modality employed to assess the mesentery due to its speed, widespread availability, and diagnostic accuracy. Pathologies affecting the mesentery can be classified as primary or secondary mesenteropathies. Primary mesenteropathies originate in the mesentery and subsequently progress to involve other organ systems (e.g., mesenteric ischemia or mesenteric volvulus). Secondary mesenteropathies describe disease processes that originate elsewhere and progress to involve the mesentery with varying degrees of severity (e.g., lymphoma). The implementation of standardized radiological imaging protocols, nomenclature, and reporting format with regard to the mesentery will be essential in improving the assessment of mesenteric anatomy and various mesenteropathies. In this article, we describe and illustrate the current state of art in respect of the radiological assessment of the mesentery.

Anatomy of the Mesentery

It is clear that despite the importance of multimodal therapy, the most impactful weapon in the arsenal of treatment in a patient with colorectal cancer is high-quality surgery. This has been shown time and time again and surgery remains the bedrock in the management of visceral, and particularly colorectal, cancer. The reason for this is an anatomical one, based upon embryological planes. One cannot truly understand and perform high-quality surgery without an appreciation of the fascial and mesenteric anatomy of the abdomen and pelvis.

R. J. (“Bill”) Heald greatly advanced the management of rectal cancer with his description of the anatomical foundation of total mesorectal excision. He popularized usage of the term “mesorectum” and was an early pioneer in the commitment to mesenteric-based surgery. This concept has been extended by Werner Hohenberger to mesocolic excision for colon cancer surgery.

These all rely on the principle that, in general, cancer tends to remain within its embryological compartment of origin, making it amenable to dissecting out as an oncological surgical envelope or package. There have been some theories put forth as to why, but it remains the fact that, far more often than not, an excision within the mesenteric plane affords better outcomes than the one that breaches it.

Thus an understanding of the anatomy of the mesentery is important and is the scientific foundation of the art that is cancer surgery.

Herein the author outlines the history of the development of our understanding of mesenteric anatomy and where we are today.

Does cranial-medial mixed dominant approach have a unique advantage for laparoscopic right hemicolectomy with complete mesocolic excision?

BACKGROUND

Complete mesocolic excision (CME) with central vascular ligation (CVL) was proposed by Hohenberger in 2009. The CME principle has gradually become the technical standard for colon cancer surgery. How to achieve CME with CVL in laparoscopic right hemicolectomy (LRH) is controversial, and a unified standard approach is not yet available. In recent years, the authors’ team has integrated the theory of membrane anatomy, tried to combine the cephalic approach with the classic medial approach (MA) for technical optimization, and proposed a cranial-medial mixed dominant approach (CMA).

AIM

To explore the feasibility of operational approaches for LRH with CME.

METHODS

In this retrospective cohort study, the clinical data of 57 patients with right-sided colon cancer (TNM stage I, II, or III) who underwent LRH with CME from January 2016 to June 2020 were collected and summarized. There were 31 patients in the traditional MA group and 26 in the CMA group.

RESULTS

There were no significant differences in baseline data between the two groups. The operation was shorter and the number of lymph nodes dissected was higher in the CMA group than in the MA group, but there was no significant difference in the number of positive lymph nodes, intraoperative blood loss, postoperative exhaust time, feeding time, postoperative hospital stay or postoperative complication incidence.

CONCLUSION

Our study shows that the CMA is a safe and feasible procedure for LRH with CME and has a unique advantage.

Re-interpreting mesenteric vascular anatomy on 3D virtual and/or physical models: positioning the middle colic artery bifurcation and its relevance to surgeons operating colon cancer

Background

The impact of the position of the middle colic artery (MCA) bifurcation and the trajectory of the accessory MCA (aMCA) on adequate lymphadenectomy when operating colon cancer have as of yet not been described and/or analysed in the literature. The aim of this study was to determine the MCA bifurcation position to anatomical landmarks and to assess the trajectory of aMCA.

Methods

The colonic vascular anatomy was manually reconstructed in 3D from high-resolution CT datasets using Osirix MD and 3-matic Medical and analysed. CT datasets were exported as STL files and supplemented with 3D printed models when required.

Results

Thirty-two datasets were analysed. The MCA bifurcation was left to the superior mesenteric vein (SMV) in 4 (12.1%), in front of SMV in 17 (53.1%) and right to SMV in 11 (34.4%) models. Median distances from the MCA origin to bifurcation were 3.21 (1.18–15.60) cm. A longer MCA bifurcated over or right to SMV, while a shorter bifurcated left to SMV (r = 0.457, p = 0.009). The main MCA direction was towards right in 19 (59.4%) models. When initial directions included left, the bifurcation occurred left to or anterior to SMV in all models. When the initial directions included right, the bifurcation occurred anterior or right to SMV in all models. The aMCA was found in 10 (31.3%) models, following the inferior mesenteric vein (IMV) in 5 near the lower pancreatic border. The IMV confluence was into SMV in 18 (56.3%), splenic vein in 11 (34.4%) and jejunal vein in 3 (9.4%) models.

Conclusion

Awareness of the wide range of MCA bifurcation positions reported is crucial for the quality of lymphadenectomy performed. The aMCA occurs in 31.3% models and its trajectory is in proximity to the lower pancreatic border in one half of models, indicating that it needs to be considered when operating splenic flexure cancer.

Supplementary information

The online version of this article (10.1007/s00464-020-08242-8) contains supplementary material, which is available to authorized users.

Surgical treatment of a colon neoplasm of the splenic flexure: a multicentric study of short-term outcomes

AIM

The optimal surgical treatment of splenic flexure neoplasm is still not well defined. Extended right hemicolectomy (ERH) and left colic resection (LCR) have been proposed but conclusive evidence concerning postoperative morbidity and oncological results is lacking. The aim of this study was to analyse the short-term outcomes after surgery for splenic flexure cancer with regard to surgical procedure and surgeon's specialty.

METHODS

This was a multicentre study on patients who underwent surgery for primary colon cancer of the splenic flexure.

RESULTS

From 2004 to 2015, 324 patients fulfilled the criteria for inclusion into the study; 270 (83.4%) had elective surgery while 54 (16.6%) had emergency resection: 158 (48.8%) underwent ERH and 166 (51.2%) LCR; 176 (54.3%) procedures were performed by colorectal surgeons, 148 (46.7%) by general surgeons. In the ERH group a significantly higher rate of emergency operations was carried out (P = 0.005). After elective surgery, no significant differences between ERH and LCR concerning 30-day mortality (3.3% vs 2.0%) and the need for reoperation (10.6% vs 7.4%) were found. Nodal harvesting was significantly higher in the ERH and colorectal surgeon groups in any clinical scenario. At multivariate analysis, age and smoking habit were predictive of the need for reoperation and major morbidity while the general surgeon group showed a higher risk of anastomotic failure (OR = 1.92; P = 0.168).

CONCLUSION

We analysed the largest series in literature of curative resections for splenic flexure tumours. The optimal procedure still remains debatable as ERH and LCR appear to achieve comparable short-term outcomes. Surgeon's specialty seems to positively affect patient's outcomes.

The Toldt fascia: A historic review and surgical implications in complete mesocolic excision for colon cancer

To clarify the anatomic concept of Toldt fascia, based on the literature review and the surgical anatomic dissection using laparoscopic or robotic approach. We undertook review of the historic literature and surgical videos from 250 patients with colorectal cancer operated on laparoscopically or robotically to discuss the surgical implications of Toldt fascia in complete mesocolic excision for colon cancer. Toldt fascia, sandwiched by the overlying mesothelial layer of the mesocolon and underlying mesothelial layer of the retroperitoneum, comprised loose fibrous tissues with minute vessels inside, and was contiguous from the ileocecal mesentery radix to the upper rectum. Surgical dissection plane is readily developed within the Toldt fascia; however, any attempt to dissect along the interface between Toldt fascia and the overlying mesocolon or underlying retroperitoneum failed. Within the anatomic territory of kidney, Toldt fascia fused with Gerota fascia, and then extended in all directions: upward to the dosal surface of the duodenum, liver and pancreas; medially to fuse with the adventitia layer of the abdominal aorta; laterally, it tapered at the area below the reflection of visceral and parietal peritoneum; and downward, it became a thin membranous structure covering the gonadal vessels, ureters and retroperitoneal structures and ended at the upper rectum, where it met the junction of endopelvic fascia and proper fascia of the rectum. The present study demonstrated that Toldt fascia is a natural embryonic dissection plane for the precise conduction of complete mesocolic excision for colon cancer.

Inclusion of the Mesentery in Ileocolic Resection for Crohn's Disease is Associated With Reduced Surgical Recurrence

BACKGROUND AND AIMS

Inclusion of the mesentery during resection for colorectal cancer is associated with improved outcomes but has yet to be evaluated in Crohn's disease. This study aimed to determine the rate of surgical recurrence after inclusion of mesentery during ileocolic resection for Crohn's disease.

METHODS

Surgical recurrence rates were compared between two cohorts. Cohort A [n = 30] underwent conventional ileocolic resection where the mesentery was divided flush with the intestine. Cohort B [n = 34] underwent resection which included excision of the mesentery. The relationship between mesenteric disease severity and surgical recurrence was determined in a separate cohort [n = 94]. A mesenteric disease activity index was developed to quantify disease severity. This was correlated with the Crohn's disease activity index and the fibrocyte percentage in circulating white cells.

RESULTS

Cumulative reoperation rates were 40% and 2.9% in cohorts A and B [P = 0.003], respectively. Surgical technique was an independent determinant of outcome [P = 0.007]. Length of resected intestine was shorter in cohort B, whilst lymph node yield was higher [12.25 ± 13 versus 2.4 ± 2.9, P = 0.002]. Advanced mesenteric disease predicted increased surgical recurrence [Hazard Ratio 4.7, 95% Confidence Interval: 1.71-13.01, P = 0.003]. The mesenteric disease activity index correlated with the mucosal disease activity index [r = 0.76, p < 0.0001] and the Crohn's disease activity index [r = 0.70, p < 0.0001]. The mesenteric disease activity index was significantly worse in smokers and correlated with increases in circulating fibrocytes.

CONCLUSIONS

Inclusion of mesentery in ileocolic resection for Crohn's disease is associated with reduced recurrence requiring reoperation.

Anatomy of the mesentery: Historical development and recent advances

Recent appraisals of mesenteric anatomy clarify its structure and show a continuous and helical-shaped organ. This new model signifies a departure from the conventional model which described multiple, separate "mesenteries". Renaissance anatomists depicted the mesentery as a continuous structure. Events that led to replacement of a continuous with a fragmented model span several centuries. In effect, the scientific and clinical community has come full circle and back to the Renaissance model. Here we review the historical development of our understanding of the mesentery. We discuss how the fragmented model replaced the continuous model. Additionally, we examine factors that contributed to recent advances in mesenteric anatomy as these present new opportunities for systematic investigation.

The development of the dorsal mesentery in human embryos and fetuses

The vertebrate intestine has a continuous dorsal mesentery between pharynx and anus that facilitates intestinal mobility. Based on width and fate the dorsal mesentery can be subdivided into that of the caudal foregut, midgut, and hindgut. The dorsal mesentery of stomach and duodenum is wide and topographically complex due to strong and asymmetric growth of the stomach. The associated formation of the lesser sac partitions the dorsal mesentery into the right-sided "caval fold" that serves as conduit for the inferior caval vein and the left-sided mesogastrium. The thin dorsal mesentery of the midgut originates between the base of the superior and inferior mesenteric arteries, and follows the transient increase in intestinal growth that results in small-intestinal looping, intestinal herniation and, subsequently, return. The following fixation of a large portion of the abdominal dorsal mesentery to the dorsal peritoneal wall by adhesion and fusion is only seen in primates and is often incomplete. Adhesion and fusion of mesothelial surfaces in the lesser pelvis results in the formation of the "mesorectum". Whether Toldt's and Denonvilliers' "fasciae of fusion" identify the location of the original mesothelial surfaces or, alternatively, represent the effects of postnatal wear and tear due to intestinal motility and intra-abdominal pressure changes, remains to be shown. "Malrotations" are characterized by growth defects of the intestinal loops with an ischemic origin and a narrow mesenteric root due to insufficient adhesion and fusion.

Intraoperative Archive of Right Colonic Vascular Variability Aids Central Vascular Ligation and Redefines Gastrocolic Trunk of Henle Variants

BACKGROUND

Vascular supply to the right colon has become an issue because of high variability and subsequent impact on minimally invasive surgery. Past cadaveric or radiologic anatomic assessments are noncomprehensive.

OBJECTIVE

Intraoperative charting of right colonic arteriovenous anatomy was undertaken to determine the incidence and scope of vascular variations.

DESIGN

Vascular anatomy variations were documented in snapshot images, captured during laparoscopic video recordings or through open surgical digital photography.

SETTINGS

Data were drawn from consecutive right hemicolectomies, routinely entailing complete mesocolic excision with central vascular ligation.

PATIENTS

Seventy patients (mean age, 62.7 years; 37 women (52.8%); 33 men (47.2%)), each with surgically treatable right-sided colon cancer, were prospectively studied.

RESULTS

Both ileocolic and middle colic arteries were regularly identified (100%), with right colic artery present in 41.4% of patients. Ileocolic and middle colic veins consistently drained into the right colon. Although the ileocolic vein always emptied into the superior mesenteric vein, drainage of the middle colic vein was split (superior mesenteric vein, 94.3%; gastrocolic trunk of Henle, 5.3%), as was drainage of the right colic (superior mesenteric vein, 43.3%; gastrocolic trunk of Henle, 56.7%) and accessory middle colic veins (superior mesenteric vein, 54.5%; gastrocolic trunk of Henle, 45.5%), present in 42.9% and 15.7% of patients. Gastrocolic trunk of Henle was found in 88.6% of patients, usually draining into the superior mesenteric vein. No significant sex-related differences were present regarding the incidence and scope of variability displayed by the right colic artery, right colic vein, accessory middle colic vein, or gastrocolic trunk of Henle classification (p > 0.05).

LIMITATIONS

The inconsistency between cadaver and live surgery anatomy and the low BMI of the Asian population might be drawbacks of our study.

CONCLUSIONS

Variations in right colonic arteriovenous channels, assessed intraoperatively, corroborate those established by cadaveric and radiologic means, prompting a new gastrocolic trunk of Henle classification.

The mesentery: structure, function, and role in disease

Systematic study of the mesentery is now possible because of clarification of its structure. Although this area of science is in an early phase, important advances have already been made and opportunities uncovered. For example, distinctive anatomical and functional features have been revealed that justify designation of the mesentery as an organ. Accordingly, the mesentery should be subjected to the same investigatory focus that is applied to other organs and systems. In this Review, we summarise the findings of scientific investigations of the mesentery so far and explore its role in human disease. We aim to provide a platform from which to direct future scientific investigation of the human mesentery in health and disease.

Laparoscopic Complete Mesocolic Excision for Stage II/III Left-Sided Colon Cancers: A Prospective Study and Comparison with D3 Lymph Node Dissection

BACKGROUND

To investigate the similarities and differences of laparoscopic complete mesocolic excision (CME) to a colon resection with a D3 lymphadenectomy for the stage II/III left-sided colon carcinoma.

METHODS

Patients between July 2011 and August 2014 were randomized into D3 and CME groups. Mesenteric area, log odds of positive lymph nodes (LODDS), and other operative parameters were collected and assessed.

RESULTS

The average specimen sizes were 5730 ± 828 mm(2) in superior rectal artery (SRA)-preserving D3, 8145 ± 1022 mm(2) in SRA-nonpreserving D3, and 8745 ± 1039 mm(2) in the CME group; the differences were significant (P < .0001). The number of lymph nodes collected from CME specimens was larger, but the CME specimens did not contain an elevated value of LODDS or positive nodes or lymph node ratio (LNR). There were also no significant differences between recovery times of bowel function. Although it took more operation time in D3 approach, especially in SRA-preserving D3 operation, the difference was not significant. Concerning the leakage rate (P = .34) and vessel-related complications (P = .64), there were no significant differences either.

CONCLUSIONS

Both standard D3 resection and CME could achieve a high quality of mesocolic plane grade for stage II/III colon cancer. The LODDS and LNR were comparable, and those were not relevant to mesenteric size.

Laparoscopic complete mesocolic excision with central vascular ligation in right colon cancer: A comprehensive review

Aim of the study is to comprehensively review the latest trends in laparoscopic complete mesocolic excision (CME) with central vascular ligation (CVL) for the multimodal management of right colon cancer. Historical and up-to-date anatomo-embryological concepts are analyzed in detail, focusing on the latest studies of the mesenteric organ, its dissection by mesofascial and retrofascial cleavage planes, and questioning the need for a new terminology in colonic resections. The rationale behind Laparoscopic CME with CVL is thoroughly investigated and explained. Attention is paid to the current surgical techniques and the quality of the surgical specimen, yielded through mesocolic, intramesocolic and muscularis propria plane of surgery. We evaluate the impact on long term oncologic outcome in terms of local recurrence, overall and disease-free survival, according to the plane of resection achieved. Conclusions are drawn on the basis of the available evidence, which suggests a pivotal role of laparoscopic CME with CVL in the multimodal management of right sided colonic cancer: performed in the right mesocolic plane of resection, laparoscopic CME with CVL demonstrates better oncologic results when compared to standard non-mesocolic planes of surgery, with all the advantages of laparoscopic techniques, both in faster recovery and better immunological response. The importance of minimally invasive meso-resectional surgery is thus stressed and highlighted as the new frontier for a modern laparoscopic total right mesocolectomy.

Complete mesocolic excision: Techniques and outcomes

Complete mesocolic excision (CME) for the treatment of colon cancer was first introduced in the West in 2008. The first aim of this procedure is to remove the afflicted colon and its accessory lymphovascular supply by resecting the colon and mesocolon in an intact envelope of visceral peritoneum, which holds potentially involved lymph nodes. The second component of CME is a central vascular tie to remove completely all lymph nodes in the central (vertical) direction. In its original iteration, CME was performed via laparotomy, although many centers preferentially perform laparoscopic surgery, with its associated benefits and similar oncological outcomes, as the standard treatment for colonic cancer. Here, we present the surgical techniques for CME in open and laparoscopic surgery, as well as the surgical, pathological and oncological outcomes of the procedure that are available to date. Because there are no randomized control trials comparing CME to “standard” colon surgery, the principles underlying CME seem anatomical and logical, and the results published from the Far East, reporting an 80% 5-year survival rate for Stage III cancer, should guide us.

Navigating the mesentery: a comparative pre- and per-operative visualization of the vascular anatomy

AIM

Awareness of anatomy is critical for performing safe surgery within the root of the mesentery. Our aim was to investigate the anatomical relationship between the superior mesenteric artery (SMA) and vein (SMV) and their branches within a predefined D3 area of the right colon and to compare preoperatively established three-dimensional (3D) mesenteric vessel anatomy from CT with that found at surgery.

METHOD

Prospective data were collected on 139 patients included in the 'Safe Radical D3 Right Hemicolectomy for Cancer Through Preoperative Biphasic Multi-detector Computed Tomography (MDCT) Angiography' trial. CT data sets were 3D reconstructed before surgery and compared with photographs taken during the operation.

RESULTS

The ileocolic artery was present and correctly identified in all patients and crossed the SMV anteriorly in 58 (41.7%). Seventeen patients had a right colic artery at surgery and there were three false-negative and one false-positive CT findings, yielding a diagnostic accuracy of 97.1%, sensitivity of 85.7% and specificity of 95.2%. Positive and negative predictive values were 94.7% and 97.5%, respectively. The middle colic artery was absent in one (0.7%) patient and multiple (nine double and one triple) in 10 (7.2%) patients. A mean of 3.8 ± 1.2 jejunal arteries and 2.0 ± 0.8 jejunal veins arose from the SMA and SMV. Jejunal veins crossed the SMA in the D3 area anteriorly in 30.9% of patients. In 26 (18.7%) patients, additional veins drained into the SMV, including pancreaticoduodenal in 16, right colic in six and both in two. The inferior mesenteric vein entered the SMV in 58 (41.7%) patients and crossed the D3 area in three (2.2%).

CONCLUSION

CT-reconstructed anatomy has high specificity, sensitivity, accuracy and reliability.

Low rectal cancer: Sphincter preserving techniques-selection of patients, techniques and outcomes

Low rectal cancer is traditionally treated by abdominoperineal resection. In recent years, several new techniques for the treatment of very low rectal cancer patients aiming to preserve the gastrointestinal continuity and to improve both the oncological as well as the functional outcomes, have been emerged. Literature suggest that when the intersphincteric resection is applied in T1-3 tumors located within 30-35 mm from the anal verge, is technically feasible, safe, with equal oncological outcomes compared to conventional surgery and acceptable quality of life. The Anterior Perineal PlanE for Ultra-low Anterior Resection technique, is not disrupting the sphincters, but carries a high complication rate, while the reports on the oncological and functional outcomes are limited. Transanal Endoscopic MicroSurgery (TEM) and TransAnal Minimally Invasive Surgery (TAMIS) should represent the treatment of choice for T1 rectal tumors, with specific criteria according to the NCCN guidelines and favorable pathologic features. Alternatively to the standard conventional surgery, neoadjuvant chemo-radiotherapy followed by TEM or TAMIS seems promising for tumors of a local stage T1sm2-3 or T2. Transanal Total Mesorectal Excision should be performed only when a board approved protocol is available by colorectal surgeons with extensive experience in minimally invasive and transanal endoscopic surgery.

Image-guided real-time navigation for transanal total mesorectal excision: a pilot study

BACKGROUND

Frameless stereotaxy for real-time, image-guided surgery has been most utilized for neurological and orthopedic surgery. Recently, our center has reported the application of real-time navigation for transanal total mesorectal excision.

METHODS

During a 5-month period (June 2013-October 2013), three male patients underwent transanal minimally invasive surgery for total mesorectal excision with image-guided real-time navigation during the transanal portion of the operation. This was completed using a frameless stereotactic navigational system as shown in a demonstration video. Male patients with anterior, locally advanced rectal cancer were selected for enrollment into the pilot study.

RESULTS

Three male patients (mean age 69) underwent transanal total mesorectal excision with stereotactic navigation during a 5-month study period. Mean operative time was 402 min, and there were no intra-operative complications recorded. The mean distance from anal verge of the tumor was 6.3 cm (range 4-8 cm). The navigational accuracy was computed to be ±3.69 mm (range ±3.20 to ±4.02 mm). The average navigation setup time was 47 min, not including scan time. The surgical specimens were found to have completely intact mesorectal envelopes (Quirke 3) in all cases. All margins, including radial and distal margins, were negative. Mean postoperative length of stay was 5 days. At a median of 18-month follow-up, there was no evidence of locoregional recurrence or distant metastatic disease.

CONCLUSION

This is the first pilot series to report the use of frameless stereotactic navigation for TAMIS-TME. Stereotactic navigation for transanal total mesorectal excision is shown to be feasible, and may aid in providing colorectal surgeons with the ability to better perform safe, high-quality surgery in select cases.

Historical development of mesenteric anatomy provides a universally applicable anatomic paradigm for complete/total mesocolic excision

Although total mesorectal excision has now become the ‘gold standard' for the surgical management of rectal cancer, this is not so for colon cancer. Recent data, provided by Hohenberger and West et al. and others, have demonstrated excellent oncological outcomes when mesenterectomy is extensive (as is implicit in the concept of a ‘high tie') and the mesenteric package not violated. Such studies highlight the importance of understanding the basics of the mesenteric organ (including the small intestinal mesentery, mesocolon, mesosigmoid and mesorectum) and of abiding to principles of planar surgery. In this review, we first offer classic descriptions of the mesocolon and then detail contemporary thinking. In so doing, we provide an anatomical basis for safe and effective complete mesocolic excision (CME) in the management of colon cancer. Finally we list opportunities associated with the new anatomical paradigm, demonstrating benefits across multiple disciplines. Perhaps most importantly, we feel that a crystallized view of mesenteric anatomy will overcome factors that have hindered the general uptake of CME.