MANEJO OPERATIVO DE LESIONES GSTRICAS

Indications Malignant tumors. Benign tumors. Intractable bleeding. Chronic ulceration and inflammation.

Contraindications Absolute Inability to completely resect primary cancer. Distant metastases. Relative High operative risk because of age or comorbidities.

Informed Consent Operative mortality rates range from 3%–7%. Resection of the spleen, pancreas, or colon may be required if a gastric tumor has invaded adjacent organs. Expected Benefits Surgical treatment of gastric malignancy with curative intent. Resolution of bleeding or obstruction from benign or malignant gastric tumors or disease processes. Potential Risks Anastomotic leak. Wound infection. Pancreatic fistulae. Intra-abdominal abscesses.

Equipment A self-retaining retractor is necessary for optimal exposure. Gastrointestinal anastomosis (GIA), thoracoabdominal (TA), and end-to-end anastomosis (EEA) staplers are often used for resection and reconstruction, and should be available.

Patient Preparation All patients should undergo fiberoptic endoscopy when neoplasm is suspected, and the diagnosis should be confirmed by multiple biopsies. Preoperative tests should be performed to determine whether distant metastases are present. Abdominal and pelvic CT scans, endoscopic ultrasound, or laparoscopy may be required for adequate staging. A first- or second-generation cephalosporin is adequate as antibiotic prophylaxis for most gastric operations. Deep venous thrombosis prophylaxis should be administered. Bowel preparation is only useful in complicated cases when intestinal decompression is required and may serve to lessen the bacterial load if an intestinal resection is required. Electrolyte and coagulation deficits should be corrected before operation.

Patient Positioning The patient should be supine, with the operating surgeon on the right side of the patient. An upper midline incision is made from the xiphoid to the umbilicus to enter the abdomen. Reverse Trendelenburg positioning facilitates exposure. Once the abdomen has been entered, a routine exploration should be performed and a nasogastric tube placed by the anesthetist.

Procedure Overview and Surgical Anatomy Figure 6–1A-C: Overview of surgical options for resection of gastric lesions. For lesions involving the cardia of the stomach, esophagogastrectomy with esophagogastrostomy is performed (Figure 6–1A). A thoracotomy combined with laparotomy may be required. To ensure blood supply to the gastric remnant, the right gastroepiploic vessels are preserved. For lesions in the body of the stomach, total gastrectomy with esophagojejunostomy is typically performed (Figure 6–1B). For antral lesions, subtotal gastrectomy with gastrojejunal reconstruction is performed (Figure 6–1C). Figure 6–2: Surgical anatomy of the stomach. The esophagus terminates in the stomach after penetrating the diaphragm at the esophageal hiatus. The stomach is divided into the fundus, body, and antrum based on differences in mucosal histology. The fundus lies to the left and superior to the esophagogastric junction. The junction of the body and antrum is approximately 6–8 cm proximal to the pylorus along the lesser curvature, to a point one-third the distance from the pylorus to the esophagogastric junction along the greater curvature. Subtotal gastrectomy resects up to 75% of the stomach, and resection is defined as distal if at least 50% remains after resection. Figure 6–1A–C Figure 6–2 Distal and Subtotal Gastrectomy For distal lesions, distal or subtotal gastrectomy has an equivalent oncologic result and fewer complications when compared with total gastrectomy. A partial gastrectomy begins with a full Kocher maneuver that mobilizes the duodenum. The lesser sac must then be entered to allow early evaluation of the posterior stomach and to aid in division of the greater omentum. With cephalad retraction of the greater omentum, the avascular plane above the transverse colon is entered to the left of the midline, avoiding disruption of the middle colic vessels. Figure 6–3: The gastrocolic omentum is then dissected from the stomach. The dissection begins at the pylorus with ligation of the right gastroepiploic artery and continues along the greater curvature. In the circumstances of benign disease, the gastroepiploic vessels may be preserved. Figure 6–4: For 50% resection, the dissection ends halfway between the pylorus and the esophagogastric junction, sparing the left gastroepiploic artery and the short gastric vessels. For a subtotal or 75% resection, the left gastroepiploic artery and a portion of the short gastric vessels are divided. The tissue attachments of the posterior antrum are then separated from the anterior pancreas and the base of the transverse mesocolon. Figure 6–5: The gastrohepatic ligament is incised, and the lesser curvature is dissected. Figure 6–6: The right gastric vessels are ligated close to the stomach. If the pylorus is inflamed, care must be taken in this area to avoid injury to both the hepatic artery and the common bile duct. Figure 6–7: The proximal duodenum is divided carefully, avoiding injury to the common bile duct. Figure 6–8: The proximal stomach is divided with a TA-90 or a GIA stapler. Figure 6–9: The gastric staple line is oversewn at the superior portion with either a continuous or running suture. Traction sutures may be used at either end of the stapled closure to prevent retraction of the gastric remnant from the operative field. Figure 6–3 Figure 6–4 Figure 6–5 Figure 6–6 Figure 6–7 Figure 6–8 Figure 6–9 Gastric Reconstruction for Distal and Subtotal Gastrectomy Figure 6–10A-C: Billroth I/Gastroduodenostomy. For gastroduodenostomy reconstruction, the duodenum is apposed to the inferior gastric staple line (Figure 6–10A). Posterior seromuscular sutures are placed using interrupted silk sutures. The stapled end of the duodenum and the inferior gastric staple line are then excised using electrocautery. All layers of the duodenum and stomach are incorporated in the inner mucosal closure, using a continuous absorbable suture (Figure 6–10B). The closure is continued anteriorly and a final anterior seromuscular layer is placed using interrupted silk sutures (Figure 6–10C). A stapled gastroduodenostomy may also be created using an EEA stapling device (not shown). A gastrotomy is created on the anterior stomach, at least 3 cm from the stapled closure using electrocautery. The EEA is passed into the anterior gastrotomy without the anvil, with the rod advancing through the posterior gastric wall. The anvil is then reattached. The EEA anvil is introduced into the duodenum after a purse-string suture has been placed using an automatic device, and the purse-string suture is tied. The stapler is fired and the anastomosis is inspected for hemostasis. The anterior gastrotomy is closed using a TA stapling device. Figure 6–11A-D: Billroth II/Gastrojejunostomy. For gastrojejunostomy reconstruction, a proximal loop of jejunum is delivered through an incision in the transverse mesocolon or anterior to the transverse colon (Figure 6–11A). Interrupted sutures are placed in a seromuscular fashion between the posterior gastric wall and the antimesenteric border of the jejunum. Incisions are then created with electrocautery in the jejunum and stomach, partially excising the stapled gastric closure. The posterior mucosal closure is initiated with a continuous absorbable suture. Corner stitches should include the anterior gastric wall, the posterior gastric wall, and the jejunum (Figure 6–11B). The posterior mucosal suture is continued along the length of the anterior aspect of the anastomosis (Figure 6–11C). An anterior layer of interrupted nonabsorbable sutures completes the closure (Figure 6–11D). A stapled gastrojejunostomy may also be created using a GIA stapling device (not shown). The anastomotic site on the posterior gastric wall is usually 2–3 cm proximal from the stapled closure. The GIA limbs are inserted in matching gastrotomy and antimesenteric enterotomy incisions are made with electrocautery. The staple line is inspected for hemostasis, and the GIA defect is closed using a TA stapler. A gastrojejunostomy may also be created in a Roux-en-Y fashion (see Figures 6–17A, 6–17B, C, 6–18, and 6–19). Figure 6–10A–C Figure 6–11A–D Total Gastrectomy For large or proximal gastric lesions, a total gastrectomy is required. Figure 6–12A: The initial steps of total gastrectomy mirror those of distal gastrectomy. Figure 6–12B: The dissection requires a complete omentectomy and continues along the length of the greater curvature, to include the left gastroepiploic artery and the short gastric vessels (if the neoplasm does not involve the spleen). Figure 6–13: Division of the gastrohepatic ligament. The right gastric artery is ligated, and if the inferior phrenic vein is encountered it can be controlled with clamps and ligated. The dissection is continued proximally by dividing the peritoneum overlying the esophagus. Figure 6–14: The stomach is then retracted cephalad to expose the left gastric artery. The vascular pedicle is encircled and clamps are placed. It is important to avoid injury to the nearby pancreas. Figure 6–15: When the entire stomach has been mobilized, the surgeon can inspect the distal esophagus and determine whether additional esophageal length is required. Mobilization of the distal esophagus within the mediastinum may be required if the neoplasm extends into the esophagus. Figure 6–16A, Figure 6–16B: Once satisfied that adequate esophageal length has been achieved, stay sutures are placed laterally in the distal esophagus to prevent retraction (Figure 6–16A). The esophagus is transected, and the stomach is removed. A purse-string suture is placed in the distal esophagus using monofilament suture in preparation for the esophagojejunal anastomosis (Figure 6–16B). Figure 6–12A Figure 6–12B Figure 6–13 Figure 6–14 Figure 6–15 Figure 6–16A Figure 6–16B Gastric Reconstruction for Total Gastrectomy Figure 6–17A, Figure 6–17B,C: Roux-en-Y esophagojejunostomy. The proximal jejunum is divided approximately 10–20 cm distal to the ligament of Treitz (Figure 6–17A). An opening is made in the transverse mesocolon to the left of the middle colic vessels above the ligament of Treitz (Figure 6–17B). The Roux limb/distal end of the transected jejunum is passed in a retrocolic fashion to the area of the distal esophagus (Figure 6–17C). The Roux limb must be placed carefully, without angulation or tension. Figure 6–18: Esophagojejunal anastomosis. The stapled jejunal end is excised to permit passage of an EEA stapler. The EEA stapler is introduced through the open end of the Roux-en-Y limb. The rod should be positioned to exit 3 cm proximally along the antimesenteric border of the jejunum. The anvil is then inserted into the distal esophagus through the purse-string suture and the purse-string is secured. The stapler is fired, completing an end-to-side esophagojejunostomy. The EEA device is removed and inspected for intact tissue rings from the esophagus and the jejunum. The anastomosis is inspected for hemostasis, and the defect of the EEA device in the jejunum is closed with a TA stapler. A nasogastric tube may then be placed with the surgeon's guidance through the anastomosis and may be used to test for anastomotic integrity after the operative field has been filled with saline. The absence of bubbling after air insufflation of the anastomosis suggests an intact suture line. Figure 6–19A, B: Completion of Roux-en-Y reconstruction. The completed esophagojejunal anastomosis is shown (Figure 6–19A). Intestinal continuity is restored by an end-to-side enteroenterostomy, approximately 50 cm distal to the esophagojejunal anastomosis (Figure 6–19B). The mesenteric defect is closed to prevent internal herniation. Figure 6–17A Figure 6–17B, C Figure 6–18 Figure 6–19A–B Lymph Node Distribution for Gastric Cancer: Figure 6–20 Figure 6–20 For a potentially curative resection of gastric cancer, en bloc resection of the lymph node groups draining the primary tumor should also be performed. This should include omental, pyloric, and lesser curvature lymph nodes. For lesions of the proximal stomach and along the greater curvature, splenectomy should also be considered to include the splenic hilar nodes. For adequate TNM staging, a minimum of 15 lymph nodes must be excised and examined histopathologically before assigning an exact N-classification. Anatomic gastric nodal groups have been described as: N1 (lesser and greater curvature perigastric nodes). N2 (splenic, left gastric, celiac axis nodes). N3 (distant hepatoduodenal and root of mesentery nodes). N4 (distant aortic and middle colic areas). Gastric resection has been classified as: D0: Removal of involved stomach and less than all relevant N1 nodes. D1: Removal of involved stomach or the entire stomach, complete omentectomy, and all N1 lymph nodes (safe standard). D2: Excision of omental bursa along with the front leaf of the transverse mesocolon, and removal of all N1 and N2 lymph nodes; splenectomy is also required. D3: Resection of above structures, as well as N3 and N4 nodes. More radical surgery (beyond D1) has not been shown to increase survival in western countries and may lead to higher complication rates.

Postoperative Care Nothing by mouth. Monitoring for return of bowel function. Early nutritional support. Parenteral or jejunal feedings are not routinely necessary but may be considered for delayed bowel function or delayed emptying. Postgastrectomy diet (six or more small meals daily, high protein, low carbohydrate, decreased liquids with meals).

Potential Complications Early Complications from general anesthesia. Wound infection. Anastomotic leak. Bleeding. Subphrenic or intra-abdominal abscess and peritonitis. Early dumping syndrome. Acute afferent loop syndrome. Rupture of duodenal stump. Late Late dumping syndrome. Obstruction. Marginal ulcer disease (in jejunum no more than 2 cm from gastrojejunal anastomosis). Pernicious anemia (caused by vitamin B12 deficiency). Alkaline reflux gastritis. Chronic afferent and efferent loop syndromes.

Pearls and Tips The extent of gastric resection required is determined by the ability to obtain microscopic disease-free margins. For distal gastrectomy, the dissection ends halfway between the pylorus and the esophagogastric junction, sparing the left gastroepiploic artery and short gastric vessels. For subtotal resection, the left gastroepiploic artery and a portion of the short gastric vessels are divided. For total gastrectomy, the dissection includes the right and left gastroepiploic arteries, and the right and left gastric vessels. In western countries, extensive lymph node resection for gastric cancer has not been shown to increase survival rates and may have more complications. A D1 resection is considered a safe standard in the United States.

References Ajani J, Bekalii-Saab T, D'Amico TA, et al. Gastric Cancer. In: NCCN Practice Guidelines in Oncology, v.1.2006. Available at: http://www.nccn.org/professionals/physician_gls/PDF/gastric.pdf. Bell RH Jr, Rikkers LF, Mulholland MW, eds. Digestive Tract Surgery. Philadelphia, PA: Lippincott-Raven Publishers; 1996. Braasch JW, Sedgewick CE, Veidenheimer MC, Ellis FH Jr, eds. Atlas of Abdominal Surgery. Philadelphia, PA: WB Saunders; 1991. Sabiston DC Jr, ed. Atlas of General Surgery. Philadelphia, PA: WB Saunders; 1994. Zinner MJ, Schwartz SI, Ellis H, eds. Maingot's Abdominal Operations. Stamford, CT: Appleton & Lange; 1997.