1. SURGICAL ANATOMY OF THE PANCREAS 1.1. Topographic anatomy The pancreas is a central abdominal organ, located in the retroperitoneum. It is important to highlight its relationship with the superior mesenteric vessels, both artery, and vein. In order to access the retroperitoneal structures and, therefore, surgically locate the pancreas, it is necessary to open the lesser sac, which is a peritoneal recess between the stomach and the posterior abdominal wall. 1.2. Internal structure The pancreatic parenchyma is divided into head, neck, body and tail. There are two main pancreatic ducts: · The main pancreatic duct (or Wirsung) originates in the pancreas’ tail and goes through the gland. Drains in the POSTERIOR INFERIOR portion of the head of the pancreas (papilla of Vater). · The accessory pancreatic duct (or Santorini) usually drains into the ANTERIOR SUPERIOR portion of the pancreas head. 1.3. Vascularization The arterial vascularization of the pancreas should be divided according to each anatomical region: · The head and the uncinate process are supplied by the pancreaticoduodenal arteries; the SUPERIOR, branch of the gastroduodenal artery, and the INFERIOR, which comes from the superior mesenteric artery (SMA). · The body and tail receive arterial supply from the pancreatic branches of the splenic artery. This vessel, which runs along the upper edge of the pancreatic body and tail, gives, along its trajectory, the dorsal, the inferior and the large pancreatic branches. In pancreatic surgery, it is mandatory to always identify the common hepatic artery, because there is significant variability in its origin, which can lead to an unwanted resection of arterial branches: · “Standard” branch of the celiac trunk · RIGHT hepatic artery arises from the SMA (16%) · COMMON hepatic artery arises from SMA (2-4,5%) · LEFT hepatic artery is a branch of the left gastric artery (14%) As for the pancreas’ venous drainage system, it is a system that runs parallel to the arterial one. It ends in the portal vein, the confluence of the splenic and superior mesenteric veins. Just as the splenic artery is located above the pancreatic body, its homologous vein does so on the posterior face. 2.KEY ANATOMICAL CONCEPTS IN PANCREATIC SURGERY 2.1. Anatomical ways for approaching the Superior Mesenteric Artery The “artery-first” approach (AFA) This is based on the fact that the arterial invasion of the tumor is the main conditioner of its resectability. Therefore, the first step in surgery should be to determine the degree of arterial involvement before performing an irreversible surgical step. The advantages are: · The possibility of completely dissecting the posterolateral margin of the tumor with a lower risk of bleeding. · To determine the degree of resectability in borderline tumors. · To determine the degree of resectability in tumors that have received neoadjuvant treatment, since it can produce periarterial stranding and make it difficult to re-stage it by computed tomography. · To make easier complex resections of Borderline or locally advanced pancreatic tumors, by favoring the arterial dissection from tumor and facilitating complex vein reconstructions. Under the heading of artery-first approach, up to 6 different techniques have been described for the SMA approach: posterior, superior, right/medial uncinate, left posterior, mesenteric and anterior approaches. There is no better technique than another. The surgeon’s decision to perform one or the other will depend on the location and size of the tumor. One must know all these approaches in order to achieve an optimal pancreatic tumor resection. Compared to conventional pancreatoduodenectomy (“artery-last”), an artery-first approach with the systematic mesopancreas dissection achieved: · Less operative time. · Less blood loss. · Lower rates of postoperative pancreatic fistula. · Lower rates of delayed gastric emptying. · Same postoperative stay, mortality and R0 rates. 2.2. The mesopancreas (SMD) The mesopancreas is the neurovascular bundle that connects the pancreatic head to the SMA and right celiac ganglion. It was first proposed by Gockel et al. (2007) in analogy to total mesorectal excision in rectal cancer, defining the concept “Systematic Mesopancreas Dissection” (SMD), which includes: · 1st and 2nd pancreatic head nerve plexuses (plPh-I and plPh-II). · Inferior pancreatoduodenal arteries (IPDAs). · Jejunal arteries and veins (JAs and JVs). · Lymph nodes (LNs). The importance of knowing the mesopancreas lies in the fact that pancreatic ductal adenocarcinoma has been seen to have perineural invasion (PNI) in 70 to 100% of cases. The perineurium contains blood vessels within it. Therefore, the ability of cancer to spread through the surrounding neuronal tissue has been demonstrated, acting as a “cancer highway”. The SMD levels of dissection were classified by Inoue et al. (2015) into 3 planes according to the extension around and along the superior mesenteric artery. The dissection through the correct plane that separates the mesopancreas from the arteries and veins (plane 3 of Inoue), allows a separation of the tumor, avoiding arterial resections, and turning unresectable tumors in resectable. This concept is called “periarterial divestment”, and has been reported in detail in a recent paper from Heidelberg University. 2.3. Periarterial divestment Based on the same concept that arterial invasion determines tumor resectability, it is mandatory to name the periarterial divestment technique, a novel operative technique which consists of the clearence of the neurolymphatic tissue around the peripancreatic visceral arteries. Its importance lies in borderline and locally advanced tumors after having received neoadjuvant treatment. This is a novel idea because it presents as an alternative to arterial resection, which has great morbidity and mortality rates. The Heidelberg group reported the importance of this technique approaching locally advanced pancreatic tumors in the Triangle operation scenario. BIBLIOGRAPHY AND REFERENCES · Sanjay P, Takaori K, Govil S, Shrikhande SV, Windsor JA. ‘Artery-first’ approaches to pancreatoduodenectomy. Br J Surg. 2012 Aug;99(8):1027-35. doi: 10.1002/bjs.8763. Epub 2012 May 9. PMID: 22569924. · Nakao A. The Mesenteric Approach in Pancreatoduodenectomy. Dig Surg. 2016;33(4):308-13. doi: 10.1159/000445014. Epub 2016 May 25. PMID: 27215213. · Inoue Y, Saiura A, Yoshioka R, Ono Y, Takahashi M, Arita J, Takahashi Y, Koga R. Pancreatoduodenectomy With Systematic Mesopancreas Dissection Using a Supracolic Anterior Artery-first Approach. Ann Surg. 2015 Dec;262(6):1092-101. doi: 10.1097/SLA.0000000000001065. PMID: 25587814. · Schneider M, Strobel O, Hackert T, Büchler MW. Pancreatic resection for cancer-the Heidelberg technique. Langenbecks Arch Surg. 2019 Dec;404(8):1017-1022. doi: 10.1007/s00423-019-01839-1. Epub 2019 Nov 14. PMID: 31728630. · Gockel I, Domeyer M, Wolloscheck T, et al. Resection of the mesopancreas (RMP): a new surgical classification of a known anatomical space. World J Surg Oncol. 2007;5:44. · Gasparini G, Pellegatta M, Crippa S, Lena MS, Belfiori G, Doglioni C, Taveggia C, Falconi M. Nerves and Pancreatic Cancer: New Insights into a Dangerous Relationship. Cancers (Basel). 2019 Jun 26;11(7):893. doi: 10.3390/cancers11070893. PMID: 31248001; PMCID: PMC6678884. · Schünke, Schulte, Schumacher, Voll, Wesker. PROMETHEUS, Texto y Atlas de Anatomía. Tomo 2: “Órganos internos”. 2nd Ed. · Martín-Pérez, Sabater-Ortí, Sánchez-Bueno. CIRUGÍA BILIOPANCREÁTICA. Guías Clínicas de la Asociación Española de Cirujanos. 2nd Ed. · Rohen, Yokochi, Lütjen-Drecoll. ATLAS DE ANATOMÍA HUMANA. Estudio fotográfico del cuerpo humano. 7th Ed. · Delaney C. et al. (2014). NETTER’S SURGICAL ANATOMY AND APPROACHES. 1st Ed.
Published
Dec 2020
According to the International Study Group of Pancreatic Surgery (ISGPS), there are 4 main complications that should be taken into account whenever pancreatic surgery is performed. 1) Postoperative pancreatic fistula (POPF) Definition: exit through drainage of any volume of measurable liquid with an amylase level > 3 times the upper limit of normal serum amylase, associated or not with relevant clinical repercussion directly related to POPF. Incidence: 10-15% in pancreatoduodenectomy, 10-30% in distal pancreatectomy and 30% in tumor enucleation. Classification according to its severity: · Biochemical leak (formerly “Grade A”): by definition, it has no clinical relevance. · Grade B: it comes with clinical repercussion but without organ failure. · Grade C: characterized by one of these three scenarios: a need for reoperation, the presence of one or multiple organ failure and/or mortality attributable to the PF. 2) Bile leakage (BL) Definition: bilirubin concentration in the drain fluid at least 3 times the serum bilirubin concentration on or after postoperative day 3, or as the need for radiological intervention or surgical reintervention as a result of biliary collections or biliary peritonitis. Classification according to its impact on patients’ clinical management: Grade A: it has little or no impact on patients' clinical management. Grade B: it requires active therapeutic intervention but is manageable without relaparotomy. Grade C: those cases in which relaparotomy is required. BL has an incidence of 0.8-4% of all hepaticojejunostomies performed in the context of pancreatoduodenectomy. In most cases they are clinically well tolerated and have good prognosis with conservative management and drainage. The initial management usually consists of interventional radiology, by stent dilation or placement. Another option when the previous ones fail is re-hepaticojejunostomy. 3) Postpancreatectomy hemorrhage (PPH) It is one of the most serious and feared complications in pancreatic surgery because it is potentially the most lethal one, especially if not diagnosed and treated immediately. According to the ISGPS 2007 consensus, it can be defined by 3 parameters: · Onset: early (≤24h after the end of the index operation) or late (>24h). · Location: intraluminal or extraluminal. · Severity: mild (Hb loss of <3 g/dL and without clinical repercussions) or severe (Hb loss of ≥3 mg/dL and/or clinical repercussion). Classification: GradeOnsetLocationSeverityAEarlyIntra/extraluminalMildB1EarlyIntra/extraluminalSevereB2LateIntra/extraluminalMildCLateIntra/extraluminalSevere An abdominal CT scan with arterial contrast should be performed immediately once hemorrhage is suspected. Usually, early postpancreatectomy hemorrhage is the result of inadequate intraoperative hemostasis, so it typically needs immediate reintervention. On the other hand, late postpancreatectomy hemorrhage usually comes from a pseudoaneurysm rupture, originated from an inflammatory process (i.e. POPF, intestinal ulceration…). Treatment is performed with endovascular coil embolization or covered stent placement. 4) Delayed gastric emptying (DGE) Definition: functional gastroparesis without any mechanical obstruction. It is the most common complication after pancreatic surgery. Its definition and severity is based in these features: · Permanence of the nasogastric tube beyond POD 4. · Inability to start oral intake from POD 7. · Presence of nausea and vomiting. · Need to use prokinetic drugs. Classification: DGE GradeNasogastric tube requiredDays of oral intoleranceVomiting/gastric distensionUse of prokineticsA4-7 days or reinsertion > POD 37+/-+/-B8-14 days or reinsertion > POD 714++C>14 days or reinsertion > POD 1421++ DGE clinical management: · Total parenteral nutrition if the patient is expected to remain ≥7 days without oral intake. · Keep the nasogastric tube in intermittent aspiration. · Prokinetic drugs: · Metoclopramide IV 10 mg every 8 hours. · Erythromycin IV 250 mg every 6 hours. · Domperidone PO 10 mg every 8 hours before meals.
Published
Jul 2020
Case A 30 years old male patient, with history of smoking, grandparents that suffered from colorectal, breast and lung cancer (appeared at an age of 45); suffered from chest pain. He underwent a thoracic X-Ray that showed a mediastinal mass. Further investigation was performed with a CT-Scan that demonstrates a lesion of almost 6 cm in the middle third of the esophagus, this mass had annular form and was producing mild dilatation of the proximal esophagus, there was contact with the trachea and aorta. By upper endoscopy the lesion was at 21 cm from the dental arch, with normal mucosa and produced extrinsic compression of the lumen. The endoscopic ultrasound corroborate the annular disposition of the tumor, non pathological lymph nodes were found. The biopsy and immunohistochemistry obtained by fine needle puncture were compatible with benign leiomyoma. Treatment This patient was proposed to perform surgical treatment and underwent a minimally invasive enucleation of the tumor. The approach was accomplished by thoracoscopy, using a 3D camera with a flexible tip. A total of 3 ports were used, one of 12mm for the camera at the 7th intercostal space and two of 5mm placed at the 5th and 9th intercostal space. The patient was positioned in prone position, using selective airway intubation. The key steps of the procedure included: opening of the parietal pleura, ligation of the azygos vein, division of the muscular wall and individualization of the tumor (hook and blunt dissection), closure of the muscular wall, revision for hemostasis and extraction of the specimen, a single fine chest tube was placed. Surgical time was 120 min without any events. Outcome The patient had an correct postoperative course, oral intake started on second day after surgery and the chest tube was removed two days later. Hospital stay was five days and the follow up one month after surgery was correct.
Published
Sep 2014
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