Radicality and safety of total mesopancreatic excision in pancreatoduodenectomy: a systematic review and meta-analysis.

BACKGROUND: Pancreatic head cancer patients who undergo pancreatoduodenectomy (PD) often experience disease recurrence, frequently associated with a positive margin status (R1). Total mesopancreas excision (TMpE) has emerged as a potential approach to increase surgical radicality and minimize locoregional recurrence. However, its effectiveness and safety remain under evaluation. METHODS: We conducted a systematic review and meta-analysis to synthesize current evidence on TMpE outcomes. A systematic search of MEDLINE, EMBASE, Cochrane, and Web of Science databases was conducted up to March 2024 to identify studies comparing TMpE with standard pancreatoduodenectomy (sPD). The risk ratio (RR) or mean difference (MD) was pooled using a random effects model. RESULTS: From 452 studies identified, 9 studies with a total of 738 patients were included, with 361 (49%) undergoing TMpE. TMpE significantly improved the R0 resection rate (RR 1.24; 95% CI 1.11-1.38; P < 0.05), reduced blood loss (MD -143.70 ml; 95% CI -247.92, -39.49; P < 0.05), and increased lymph node harvest (MD 7.27 nodes; 95% CI 4.81, 9.73; P < 0.05). No significant differences were observed in hospital stay, postoperative complications, or mortality between TMpE and sPD. TMpE also significantly reduced overall recurrence (RR 0.53; 95% CI 0.35-0.81; P < 0.05) and local recurrence (RR 0.39; 95% CI 0.24-0.63; P < 0.05). Additionally, the risk of pancreatic fistula was lower in the TMpE group (RR 0.66; 95% CI 0.52-0.85; P < 0.05). CONCLUSION: Total mesopancreas excision significantly increases the R0 resection rate and reduces locoregional recurrence while maintaining an acceptable safety profile when compared with standard pancreatoduodenectomy. Further prospective randomized studies are warranted to determine the optimal surgical approach for total mesopancreatic resection.

Thick mesopancreas is a novel predictor of surgical outcomes of patients who undergo pancreaticoduodenectomy.

PURPOSE: Mesopancreas resection is a crucial but difficult procedure when performing pancreaticoduodenectomy. This study evaluated the influence of mesopancreas thickness on surgical outcomes in patients undergoing pancreaticoduodenectomy. METHODS: We measured the thickness of the fat tissue on the right side of the superior mesenteric artery from the dorsal margin of the confluence of the superior mesenteric vein and portal vein to the ventral margin of the left renal vein on preoperative contrast-enhanced computed tomography and defined it as the mesopancreas thickness. We evaluated the correlation between mesopancreas thickness and intraoperative and postoperative variables in 357 patients who underwent pancreaticoduodenectomy. RESULTS: Multivariate analysis revealed that a thick mesopancreas was significantly associated with a long operative time (ß = 10.361; 95% confidence interval, 0.370-20.353, p = 0.042), high estimated blood loss (ß = 36.038; 95% confidence interval, -27.192-99.268, p = 0.013), and a low number of resected lymph nodes (ß = -1.551; 95% confidence interval, -2.662--0.439, p = 0.006). This analysis further revealed that thick mesopancreas was a significant risk factor for overall morbidity (odds ratio 2.170; 95% confidence interval 1.340-3.520, p = 0.002), major morbidity (odds ratio 2.430; 95% confidence interval 1.360-4.340, p = 0.003), and a longer hospital stay (ß = 2.386; 95% confidence interval 0.299-4.474, p = 0.025). CONCLUSION: A thick mesopancreas could predict a longer operation time, higher estimated blood loss, fewer resected lymph nodes, more frequent overall and major morbidities, and a longer hospital stay in patients who underwent pancreaticoduodenectomy more precisely than the body mass index.

Levels of Robotic Mesopancreas Dissection According to Malignancy and Vascular Anatomy: What Surgeons Need to Know.

INTRODUCTION: The robotic approach is attracting increasing interest among the surgical community, and more and more series describing robotic pancreatoduodenectomy have been reported. Thus, surgeons performing robotic pancreatoduodenectomy should be confident with this critical step's potential scenarios. MATERIALS AND METHODS: According to Yosuke et al., there are three different levels of mesopancreas dissection. We describe the main steps for a safe mesopancreas dissection by robotic approach. RESULTS: This multimedia article provides, for the first time in literature, a comprehensive step-by-step overview of the mesopancreas dissection during robotic pancreatoduodenectomy (PD) and its three different levels according to tumor type. CONCLUSIONS: Through the tips and indications presented in this multimedia article, we aim to familiarize surgeons with the mesopancreas dissections levels according to type of malignancy and vascular anatomy.

Pancreaticoduodenectomy with superior mesenteric artery first-approach combined total meso-pancreas excision for periampullary malignancies: A high-volume single-center experience with short-term outcomes.

Backgrounds/Aims: Pancreaticoduodenectomy (PD) is the only radical treatment for periampullary malignancies. Superior mesenteric artery (SMA) first approach combined with total meso-pancreas (MP) excision was conducted to improve the oncological results. There has not been any previous research of a technique that combines the SMA first approach and total MP excision with a detailed description of the MP macroscopical shape. Methods: We prospectively assessed 77 patients with periampullary malignancies between October 2020 and March 2022 (18 months). All patients had undergone PD with SMA first approach combined total MP excision. The perioperative indications, clinical data, intra-operative index, R0 resection rate of postoperative pathological specimens (especially mesopancreatic margin), postoperative complications, and follow-up results were evaluated. Results: The median operative time was 289.6 min (178-540 min), the median intraoperative blood loss was 209 mL (30-1,600 mL). Microscopically, there were 19 (24.7%) cases with metastatic MP, and five cases (6.5%) with R1-resection of the MP. The number of lymph nodes (LNs) harvested and metastatic LNs were 27.2 (maximum was 74) and 1.8 (maximum was 16), respectively. Some (46.8%) patients had pancreatic fistula, but mostly in grade A, with 7 patients (9.1%) who required re-operations. Some 18.2% of cases developed postoperative refractory diarrhea. The rate of in-hospital mortality was 1.3%. Conclusions: The PD with SMA first approach combined TMpE for periampullary malignancies was effective in achieving superior oncological statistics (rate of MP R0-resection and number of total resected LNs) with non-inferior short-term outcomes. It is necessary to evaluate survival outcomes with long-term follow-up.

Reappraisal of surgical and survival outcomes of 500 consecutive cases of robotic pancreaticoduodenectomy.

BACKGROUND: The role of the robotic approach for pancreaticoduodenectomy has not been well established with robust data. This study aimed to reappraise feasibility and justification of robotic pancreaticoduodenectomy (RPD) over time. METHODS: A total of 500 patients undergoing RPD were enrolled and divided into early (first 250 patients) and late (last 250 patients) groups for a comparative study. RESULTS: The conversion rate was 8.8% overall and was significantly lower in the late group (5.6% vs. 12.0%; p = .012). The overall median intraoperative blood loss was 130 mL. Radicality of resection was similar between early and late groups. The overall surgical mortality after RPD was 1.3%. The overall surgical morbidity and major complication was 44.1% and 13.2%, respectively, and similar between early and late groups. Chyle leakage was the most common complication after RPD (25.0%), followed by postoperative pancreatic fistula (POPF). The POPF rate was 8.6% overall, with 5.9% in the early group and 11.0% in the late group, p = .051. The overall delayed gastric emptying rate was 3.5%. The late group had better survival outcomes than those of the early group after RPD for ampullary adenocarcinoma (p = .027) but not for pancreatic head adenocarcinoma. CONCLUSIONS: Reappraisal of this study has confirmed that RPD is not only technically feasible without increasing surgical risks but also oncologically justified without compromising survival outcomes for both pancreatic head and other periampullary cancers over time. Moreover, RPD is associated with the benefits of low surgical mortality, blood loss, and delayed gastric emptying.

A more radical perspective on surgical approach and outcomes in pancreatic cancer-a narrative review.

Background and Objective: Pancreatic adenocarcinoma remains a dismal disease and is expected to become an even greater burden in the near future. This review focuses on the different surgical aspects for pancreaticoduodenectomy (PD), distal and total pancreatectomy (TP), incorporating lessons from both the western and eastern visions in treating pancreatic cancer. Methods: We conducted an extensive literature review through PubMed, prioritizing papers published in the last 5 years, but older emblematic papers were also included. We included articles that explored the treatment of pancreatic adenocarcinoma, with focus on the surgical aspect and strategies to improve outcomes. References of selected articles were also reviewed to identify any missed studies. Only papers in English were included. Key Content and Findings: As evidence continues to build, it is clear that both systemic and surgical therapies have a fundamental and complementary role. State of art surgical treatment encompasses complete mesopancreas excision for radical lymphadenectomy. Preoperative planning of dissection planes, extensive knowledge of vascular anatomic variations, oncological principles and expertise for vascular resections are mandatory to perform a more radical operation, in pursuit of improved outcomes. Conclusions: Based on current data, patient selection remains key and a more radical surgical approach brings more accomplishing results bringing as to believe that more is better.

Perioperative Outcomes of Systematic Mesopancreas Dissection for Pancreatic and Periampullary Carcinoma at a Tertiary Referral Center From a Low Middle-Income Country.

Introduction Systematic mesopancreas dissection (SMD) is an emerging surgical approach in pancreatic cancer surgery. There is still debate about early postoperative and pathological outcomes using SMD in pancreatic cancer surgery. This study has been conducted to compare the perioperative outcomes, the lymph node yield, and the margin status in patients who underwent standard pancreaticoduodenectomy (ST-PD) and SMD-PD for pancreatic and periampullary carcinoma. Methods A retrospective comparative study was conducted in patients who underwent PD for pancreatic and periampullary carcinoma in a single unit of gastrointestinal and hepatopancreatobiliary surgery at Tribhuvan University Teaching Hospital, Nepal. Early perioperative and pathological outcomes were compared between the SMD-PD and ST-PD. Results The demographic data of 30 patients who underwent SMD-PD was comparable with the historical data of 40 patients who underwent ST-PD. The intraoperative blood loss and postoperative complications were found to be comparable between ST-PD and SMD-PD. However, the median operative time for SMD-PD was longer than ST-PD (360 minutes [IQR: 90 minutes] vs. 360 minutes [IQR: 60 minutes]). The rate of margin negative resection was similar between both groups. The median lymph node yield was significantly high in patients who underwent SMD-PD (17.5 (IQR: 6.5) vs. 11 [IQR-10.75]; p < 0.05). Conclusion SMD is safe and feasible for treating periampullary carcinoma and is particularly helpful in increasing lymph node yield.

Comparative study of pancreatic vessels and mesopancreas of rhesus monkeys and humans.

Introduction: With the introduction of the concept of mesopancreas defining the perineural structures that includes neurovascular bundle and lymph nodes extending from the posterior surface of the pancreatic head to behind the mesenteric vessels,Total Mesopancreas Excision (TMpE) based on this theory has facilitated the development of pancreatic cancer surgery in clinical practice in recent years. However, the existence of so called mesopancreas in the human body is still in debate and the comparative study of mesopancreas of rhesus monkey and human have not been well investigated. Purpose: The aim of our study is to compare the pancreatic vessels and fascia of human and rhesus monkeys in anatomical and embryological perspectives and to support the utilization of rhesus monkey as animal model. Methods: In this study, 20 rhesus monkey cadavers were dissected and their mesopancreas location, relationships and arterial distribution were analyzed. We compared the location and developmental patterns of mesopancreas in macaques and humans. Results: The results showed that the distribution of pancreatic arteries in rhesus monkeys was the same as that in humans, which is consistent with phylogenetic similarities. However, the morphological features of the mesopancreas and greater omentum is anatomically different from that of humans, including (1) the greater omentum is not connected to the transverse colon in monkeys. (2) The presence of the dorsal mesopancreas of the rhesus monkey suggests that it be an intraperitoneal organ. Comparative anatomical studies of mesopancreas and arteries in macaques and humans showed characteristic patterns of mesopancreas and similarities in pancreatic artery development in nonhuman primates, consistent with phylogenetic differentiation.

Surgical Anatomy of the Mesopancreas in Obese Patients: A Retrospective Study.

Introduction The mesopancreas is described as a triangle formed by the superior mesenteric vein, celiac axis (CA), and superior mesenteric artery (SMA). It is the most likely site of residual cancer and local recurrence after surgical resection, making it the key site of the current radical resection of pancreatic head cancer. The surgical anatomy of the mesopancreas triangle has not been studied in detail. Furthermore, to the best of our knowledge, no information is available on the impact of obesity on the anatomy of the mesopancreas triangle. Methods Between January 2016 and August 2016, 200 consecutive triple-phase computed tomography scans of the abdomen were performed and included in this retrospective study aiming to define the anatomical relation of the left renal vein (LRV) to the root of the SMA and focusing on the relevance of the LRV as a landmark to guidance for the dissection of the mesopancreas. Furthermore, by studying six surgically relevant anatomical parameters namely the thickness of the areolar tissue separating the LRV from the root of the SMA, IVC from the root of the SMA, the left adrenal vein (LAV) from the root of the SMA, splenic vein from the aorta, and CA from the SMA at two levels, we investigated the impact of obesity on the mesopancreas anatomy. Results The mean distance from the upper border of the LRV to the root of the SMA (LRV-SMA distance) was 2.3 ± 5.4 mm. There was no correlation between this distance and patient's age (r = -0.02), height (r = -0.07), BMI (r = -0.01), visceral fat area (r = -0.04), or abdominal circumference (r = -0.02). There was no correlation between the distance from the IVC to the root of the SMA, and patient's age (r = 0.01), height (r = 0.11), BMI (r = 0.15), or abdominal circumference (r = 0.00). However, there was a negligible correlation between the IVC-SMA distance and patient's visceral fat area (r = 0.15, p = 0.036). Conclusion In the current study, the LRV was reliably identified in more than 99% of the studied patients, and in 96% of patients, the LRV crosses anterior to the aorta at the level of the second lumbar vertebra, making it easily accessible following mobilization of the duodenum and the head of the pancreas. The relationship between the LRV and SMA remains unchanged following Kocherization. Most importantly, we demonstrated that the LRV-SMA distance does not correlate with patient's age, height, BMI, visceral fat area, or abdominal circumference. This makes the LRV a reliable landmark in both obese and non-obese patients.

Pancreatic head cancer - Current surgery techniques.

Pancreatic head cancer is a highly fatal disease. For now, surgery offers the only potential long-term cure albeit with a high risk of complications. However, the progress of surgical technique during the past decade has resulted in 5-year survival approaching 30% after resection and adjuvant chemotherapy. This paper presents current data on the recommended extent of lymphadenectomy, the resection margin, on the definition of resectable and borderline resectable tumors and mesopancreas. Surgical techniques proposed to improve PD are presented: the artery first approach, the uncinate process first, the mesopancreas first approach, the triangle operation, periarterial divestment, and multiorgan resection.

A safety study of intraoperative radiation therapy following stereotactic body radiation therapy and multi-agent chemotherapy in the treatment of localized pancreatic adenocarcinoma: study protocol of a phase I trial.

BACKGROUND: Localized pancreatic adenocarcinoma carries a poor prognosis even after aggressive therapy. Up to 40% of patients may develop locoregional disease as the first site of failure. As such, there may be a role for intensification of local therapy such as radiation therapy. Radiation dose escalation for pancreatic cancer is limited by proximity of the tumor to the duodenum. However, the duodenum is removed during Whipple procedure, allowing the opportunity to dose escalate with intraoperative radiation therapy (IORT). Although prior studies have shown potential benefit of IORT in pancreatic cancer, these studies did not utilize ablative doses (biologically effective dose [BED10] > 100 Gy). Furthermore, the optimal radiation target volume in this setting is unclear. There has been increased interest in a "Triangle Volume" (TV), bordered by the celiac axis, superior mesenteric artery, common hepatic artery, portal vein, and superior mesenteric vein. Dissection of this area, has been advocated for by surgeons from Heidelberg as it contains extra-pancreatic perineural and lymphatic tracts, which may harbor microscopic disease at risk of mediating local failure. Interestingly, a recent analysis from our institution indicated that nearly all local failures occur in the TV. Therefore, the purpose of this protocol is to evaluate the safety of delivering an ablative radiation dose to the TV with IORT following neoadjuvant chemotherapy and stereotactic body radiation therapy (SBRT). METHODS: Patients with non-metastatic pancreatic adenocarcinoma centered in the head or neck of the pancreas will be enrolled. Following treatment with multi-agent neoadjuvant chemotherapy, patients will undergo SBRT (40 Gy/5 fractions) followed by IORT (15 Gy/1 fraction) to the TV during the Whipple procedure. The primary objective is acute (< 90 days) toxicity after IORT measured by Clavien-Dindo classification. Secondary objectives include late (> 90 days) toxicity after IORT measured by Clavien-Dindo classification, overall survival, local progression-free survival, distant metastasis-free survival, and progression-free survival. DISCUSSION: If the results show that delivering an ablative radiation dose to the TV with IORT after neoadjuvant chemotherapy and SBRT is safe and feasible, it warrants further investigation in a phase II trial to evaluate efficacy of this approach. Trial Registration This study was registered at ClinicalTrials.gov on 12/2/2021 (NCT05141513). https://clinicaltrials.gov/ct2/show/NCT05141513.

The Story Retold: The Kocher Manoeuvre.

The Kocher manoeuvre is used for mobilization of the duodenum and head of the pancreas and bears the name of Theodor Kocher, who published it in 1903. We describe the embryology of the duodenum and pancreas, relating it to surgical anatomy applied during the procedure. Finally, we present the key points of the procedure, providing more insights into the anatomical structures that are mainly involved.

Total mesopancreas excision is the better staging tool of the mesopancreas in pancreatic head carcinoma.

Preoperative imaging staging based on tumor, node, metastasis classification cannot be effective to avoid R1 resection because only further improvements in imaging technologies will allow the precise assessment of perineural and lymphatic invasion and the occurrence of microscopic tumour deposits in the mesopancreas. However, waiting for further improvements in imaging technologies, total mesopancreas excision remains the only tool able to precisely assess mesopancreatic resection margin status, maximize the guarantee of radicality in cases of negative (R0) mesopancreatic resection margins, and stage the mesopancreas.

Dissection Around the Superior Mesenteric Artery (SMA) Using LigaSure Maryland During Left Posterior Approach for Pancreaticoduodenectomy.

R0 resection for pancreatic head cancer without exposing the tumor demands complete resection of "mesopancreas". In other words, dividing the proximal jejunal artery and vein at their roots of the superior mesenteric artery (SMA) and superior mesenteric vein (SMV) respectively during pancreaticoduodenectomy (PD) is absolutely essential. We present here our standardized dissection procedures around the SMA during the left posterior approach for PD. This procedure is safe and reproducible owing to the secure sealing performance of LigaSureTM Maryland.

Feasibility of "cold" triangle robotic pancreatoduodenectomy.

BACKGROUND: Triangle pancreatoduodenectomy adds to the conventional procedure the en bloc removal of the retroperitoneal lympho-neural tissue included in the triangular area bounded by the common hepatic artery (CHA), the superior mesenteric artery (SMA), and the superior mesenteric vein/portal vein. We herein aim to show the feasibility of "cold" triangle robotic pancreaticoduodenectomy (C-Tr-RPD) for pancreatic cancer (PDAC). METHODS: Cold dissection corresponds to sharp arterial divestment performed using only the tips of robotic scissors. After division of the gastroduodenal artery, triangle dissection begins by lateral-to-medial divestment of the CHA and anterior-to-posterior clearance of the right side of the celiac trunk. Next, after a wide Kocher maneuver, the origin of the SMA, and the celiac trunk are identified. After mobilization of the first jejunal loop and attached mesentery, the SMA is identified at the level of the first jejunal vein and is divested along the right margin working in a distal-to-proximal direction. Vein resection and reconstruction can be performed as required. C-Tr-RPD was considered feasible if triangle dissection was successfully completed without conversion to open surgery or need to use energy devices. Postoperative complications and pathology results are presented in detail. RESULTS: One hundred twenty-seven consecutive C-Tr-RPDs were successfully performed. There were three conversions to open surgery (2.3%), because of pneumoperitoneum intolerance (n = 2) and difficult digestive reconstruction. Thirty-four patients (26.7%) required associated vascular procedures. No pseudoaneurysm of the gastroduodenal artery was observed. Twenty-eight patients (22.0%) developed severe postoperative complications (≥ grade III). Overall 90-day mortality was 7.1%, declining to 2.3% after completion of the learning curve. The median number of examined lymph nodes was 42 (33-51). The rate of R1 resection (7 margins < 1 mm) was 44.1%. CONCLUSION: C-Tr-RPD is feasible, carries a risk of surgical complications commensurate to the magnitude of the procedure, and improves staging of PDAC.

Anatomical Study of the Duodenojejunal Uncinate Process Vein: A Key Landmark for Mesopancreatoduodenal Resection During Pancreaticoduodenectomy.

Background: The mesopancreas or mesopancreatoduodenum is an important anatomical concept during pancreaticoduodenectomy (PD) in patients with periampullary carcinoma. This study investigated whether the duodenojejunal uncinate process vein (DJUV), which is defined as the vein draining from the upper jejunum to the superior mesenteric vein adjacent to the uncinate process, is a useful anatomical landmark for the caudal border of mesopancreatoduodenum resection during PD. Methods: This study enrolled 100 adult patients with hepatobiliary pancreatic disease who underwent preoperative multidetector-computed tomography (CT). The anatomy of the key blood vessels involved during PD, and the relationship between these vessels and the DJUV, were analyzed by preoperative CT. Results: The first jejunal vein was the DJUV in 85 cases, whereas the second jejunal vein was the DJUV in 15 cases. Furthermore, the DJUV was classified into two subtypes depending on its positional relationship with the superior mesenteric artery (SMA). The inferior pancreaticoduodenal artery and vein were located on the cranial side of the DJUV in all cases. The distance between the middle colonic artery, used as a guide for regional lymph nodes, and the point where the DJUV intersected the SMA was within 10 mm in 80% of cases. These results imply that using the DJUV as a landmark for the caudal border of the mesopancreatoduodenum provides a safe approach and enables sufficient dissection of regional lymph nodes and tissues around the SMA. Conclusion: The DJUV may be a useful anatomical landmark for the caudal border of the mesopancreatoduodenum resection during PD.

Application and progress of medical imaging in total mesopancreas excision for pancreatic head carcinoma.

Pancreatic head carcinoma (PHC) is one of the common gastrointestinal malignancies with a high morbidity and poor prognosis. At present, radical surgery is still the curative treatment for PHC. However, in clinical practice, the actual R0 resection rate, the local recurrence rate, and the prognosis of PHC are unsatisfactory. Therefore, the concept of total mesopancreas excision (TMpE) is proposed to achieve R0 resection. Although there have various controversies and discussions on the definition, the range of excision, and clinical prognosis of TMpE, the concept of TMpE can effectively increase the R0 resection rate, reduce the local recurrence rate, and improve the prognosis of PHC. Imaging is of importance in preoperative examination for PHC; however, traditional imaging assessment of PHC does not focus on mesopancreas. This review discusses the application of medical imaging in TMpE for PHC, to provide more accurate preoperative evaluation, range of excision, and more valuable postoperative follow-up evaluation for TMpE through imaging. It is believed that with further extensive research and exploratory application of TMpE for PHC, large-sample and multicenter studies will be realized, thus providing reliable evidence for imaging evaluation.

Pre-Operative MDCT Staging Predicts Mesopancreatic Fat Infiltration-A Novel Marker for Neoadjuvant Treatment?

The rates of microscopic incomplete resections (R1/R0CRM+) in patients receiving standard pancreaticoduodenectomy for PDAC remain very high. One reason may be the reported high rates of mesopancreatic fat infiltration. In this large cohort study, we used available histopathological specimens of the retropancreatic fat and correlated high resolution CT-scans with the microscopic tumor infiltration of this area. We found that preoperative MDCT scans are suitable to detect cancerous infiltration of this mesopancreatic tissue and this, in turn, was a significant indicator for both incomplete surgical resection (R1/R0CRM+) and worse overall survival. These findings indicate that a neoadjuvant treatment in PDAC patients with CT-morphologically positive infiltration of the mesopancreas may result in better local control and thus improved resection rates. Mesopancreatic fat stranding should thus be considered in the decision for neoadjuvant therapy. Background: Due to the persistently high rates of R1 resections, neoadjuvant treatment and mesopancreatic excision (MPE) for ductal adenocarcinoma of the pancreatic head (hPDAC) have recently become a topic of interest. While radiographic cut-off for borderline resectability has been described, the necessary extent of surgery has not been established. It has not yet been elucidated whether pre-operative multi-detector computed tomography (MDCT) staging reliably predicts local mesopancreatic (MP) fat infiltration and tumor extension. Methods: Two hundred and forty two hPDAC patients that underwent MPE were analyzed. Radiographic re-evaluation was performed on (1) mesopancreatic fat stranding (MPS) and stranding to peripancreatic vessels, as well as (2) tumor diameter and anatomy, including contact to peripancreatic vessels (SMA, GDA, CHA, PV, SMV). Routinely resected mesopancreatic and perivascular (SMA and PV/SMV) tissue was histopathologically re-analyzed and histopathology correlated with radiographic findings. A logistic regression of survival was performed. Results: MDCT-predicted tumor diameter correlated with pathological T-stage, whereas presumed tumor contact and fat stranding to SMA and PV/SMV predicted and correlated with histological cancerous infiltration. Importantly, mesopancreatic fat stranding predicted MP cancerous infiltration. Positive MP infiltration was evident in over 78%. MPS and higher CT-predicted tumor diameter correlated with higher R1 resection rates. Patients with positive MP stranding had a significantly worse overall survival (p = 0.023). Conclusions: A detailed preoperative radiographic assessment can predict mesopancreatic infiltration and tumor morphology and should influence the decision for primary surgery, as well as the extent of surgery. To increase the rate of R0CRM- resections, MPS should be considered in the decision for neoadjuvant therapy.

Paraaortic dissection in "total mesopancreas excision" and "mesopancreas-first resection" pancreaticoduodenectomies for pancreatic cancer: Useless, optional, or necessary?A systematic review.

The mesopancreas does not have well-defined boundaries but is continuous and connected through its components with the paraaortic area. The mesopancreatic resection margin has been indicated as the primary site for R1 resection after PD in pancreatic head cancer and total mesopancreas excision has been proposed to achieve adequate retropancreatic margin clearance and to minimize the likelihood of R1 resection. However, the anatomy of the mesopancreas requires extended dissection of the paraaortic area to maximize posterior clearance. The artery-first surgical approach has been developed to increase local radicality at the mesopancreatic resection margin. During PD, the artery-first approach begins with dissection of the connective tissues around the SMA. However, the concept of the mesopancreas as a boundless structure that includes circumferential tissues around the SMA, SMV, and paraaortic tissue highlights the need to shift from artery-first PD to mesopancreas-first PD to reduce the risk of R1 resection. From this perspective the "artery-first" approach, which allows for the avoidance of R2 resection risk, should be integrated into the "mesopancreas-first" approach to improve the R0 resection rate. In total mesopancreas excision and mesopancreas-first pancreaticoduodenectomies, the inclusion of the paraaortic area and circumferential area around the SMA in the resection field is necessary to control the tumour spread along the mesopancreatic resection margin rather than to control or stage the spread in the nodal basin.

Reconsideration of the Appropriate Dissection Range Based on Japanese Anatomical Classification for Resectable Pancreatic Head Cancer in the Era of Multimodal Treatment.

Patients with resectable pancreatic cancer are considered to already have micro-distant metastasis, because most of the recurrence patterns postoperatively are distant metastases. Multimodal treatment dramatically improves prognosis; thus, micro-distant metastasis is considered to be controlled by chemotherapy. The survival benefit of "regional lymph node dissection" for pancreatic head cancer remains unclear. We reviewed the literature that could be helpful in determining the appropriate resection range. Regional lymph nodes with no suspected metastases on preoperative imaging may become areas treated with preoperative and postoperative adjuvant chemotherapy. Many studies have reported that the R0 resection rate is associated with prognosis. Thus, "dissection to achieve R0 resection" is required. The recent development of high-quality computed tomography has made it possible to evaluate the extent of cancer infiltration. Therefore, it is possible to simulate the dissection range to achieve R0 resection preoperatively. However, it is often difficult to distinguish between areas of inflammatory changes and cancer infiltration during resection. Even if the "dissection to achieve R0 resection" range is simulated based on the computed tomography evaluation, it is difficult to identify the range intraoperatively. It is necessary to be aware of anatomical landmarks to determine the appropriate dissection range during surgery.