domingo, 11 de febrero de 2018

GASTRECTOMIA

Current Procedures: Surgery > Chapter 6. Operative Management of Gastric Lesions >

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.

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.






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).

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).






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.



Lymph Node Distribution for Gastric Cancer: 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. 

APENDICECTOMIA

Current Procedures: Surgery > Chapter 20. Appendectomy >

Indications
  • Clinical suspicion of appendicitis in an ill-appearing patient.
Contraindications
Absolute
  • None.
Relative
  • Presence of large periappendiceal abscess, which may be treated best with initial drainage and interval appendectomy.
  • Suspicion of Crohn's disease involving the cecum at the base of the appendix.
Informed Consent
Expected Benefits
  • Treatment of acute appendicitis.
Potential Risks
  • Bleeding requiring reoperation.
  • Surgical site infection (deep or superficial).
  • Fecal fistula.
  • Conversion to open appendectomy.
  • Need for midline laparotomy.
  • Open wound.
  • Need for additional tests or procedures.
Equipment
  • The open procedure requires no special equipment.
  • The laparoscopic procedure requires the following equipment:

    • 5-mm angled laparoscope.
    • Veress needle or Hasson trocar.
    • Endoscopic stapler.
    • Endoscopic retrieval bag for removal of the appendix.
Patient Preparation
  • No oral intake; maintenance intravenous fluids.
  • Preoperative antibiotics to cover enteric flora.
Patient Positioning
Open Appendectomy
  • The patient should be supine with both arms extended.
  • The entire abdomen is prepared and draped in case a midline incision is needed (eg, unexpected disease is encountered or the operative course dictates it).
Laparoscopic Appendectomy
  • Figure 20–1: The patient is supine with both arms tucked at the sides. The operating surgeon and assistant stand on the patient's left.
  • A Foley catheter is placed to decompress the bladder.
  • The patient's entire abdomen is prepared and draped.
Procedure
Open Appendectomy
  • The classic transverse incision can be made with two thirds of the incision lateral to McBurney's point.
  • Alternatively, the point of maximal tenderness or the location of the appendix based on preoperative imaging can be used to determine the location of the incision.
  • Figure 20–2: A scalpel is used to incise the epidermis and the dermis. Bovie electrocautery is used to dissect down to the external oblique aponeurosis.

    • The aponeurosis is opened in a superolateral to inferomedial direction along the direction of its fibers to expose the internal oblique muscle.
    • The internal oblique muscle is bluntly divided perpendicular to the direction of its fibers.
    • The transverse abdominal muscle is similarly divided and the peritoneum is identified.
  • Figure 20–3: The peritoneum is grasped with forceps and incised with a 15-blade knife.
  • Attention is now focused on locating the appendix.

    • If the cecum is visualized, it can be used as a guide to help identify the appendix.
    • Babcock forceps can be used to grasp the taeniae coli and advanced until the appendix is externalized.
  • Alternatively, a finger can be swept around the cecum, beginning superolaterally and continuing inferomedially to locate the appendix.
  • Figure 20–4: Once identified, the mesoappendix is dissected and the appendiceal vessels are divided between clamps and ligated with silk sutures.
  • Figure 20–5: A silk purse-string suture is placed around the base of the appendix. A right-angle clamp is applied to the base of the appendix and used to crush the tissue.
  • The clamp is moved distally and an absorbable suture is used to ligate the appendix at the base at the site of the crushed tissue. A 15-blade is used to excise the appendix proximal to the level of the clamp.
  • Figure 20–6A, B: The mucosa of the appendiceal stump may then be obliterated with electrocautery (Figure 20–6A). The purse-string suture is then used to invert the stump (Figure 20–6B).
  • The wound is irrigated with warm saline to remove any inflammatory debris and hemostasis is achieved.
  • Figures 20–7 and 20–8. The peritoneum and fascial layers are closed with running absorbable sutures.
  • The skin is closed with monofilament absorbable suture.






Laparoscopic Appendectomy
  • A 12-mm infraumbilical incision is made and access to the abdomen is achieved using either a Veress needle or Hasson technique (see Figure 20–1). The peritoneal cavity is then insufflated with carbon dioxide gas and a 5-mm angled laparoscope is inserted.
  • A 5-mm port is placed in the midline above the pubic bone and a second 5-mm port is placed laterally in the left lower quadrant (see Figure 20–1). The laparoscope is inserted through this lateral port, while the surgeon operates through the midline ports.
  • Exploration of the abdomen is performed to rule out other disease. Attention then turns to the right lower quadrant.
  • The patient is placed into steep Trendelenburg position with right side up to facilitate exposure.
  • The omentum and small bowel are swept cephalad.
  • The terminal ileum is identified by its antimesenteric fat (fold of Treves).
  • The terminal ileum is then followed to the cecum. The appendix can usually be identified by following the teniae of the cecum.
  • In the case of a retrocecal appendix, the cecum and ascending colon may need to be mobilized by division of the lateral retroperitoneal attachments.
  • Inflammatory adhesions between small bowel, cecum, and appendix are often encountered and can usually be divided using blunt dissection, although sharp dissection may be required.
  • Cautery should be avoided near the bowel.
  • Once visualized, the tip of the appendix is grasped and elevated anteriorly off of the cecum.
  • A Maryland dissector is used to create a window between the base of the appendix and the mesoappendix as shown in Figure 20–4.
  • The safest orientation of dissection is to place the appendix and its mesoappendix parallel to the lateral abdominal wall, thus minimizing the risk of bowel injury.
  • The mesoappendix is divided with an endoscopic stapler using a vascular staple load.
  • The appendix is divided at its base using a second load of the endoscopic stapler, making sure that the stapler is apposed to the cecum so that an appendiceal stump is not left in place.
  • The appendix is placed into an endoscopic retrieval bag and removed through the supraumbilical port.
  • The appendiceal and mesoappendiceal staple lines are assessed for integrity and hemostasis.
  • The abdomen is irrigated in all quadrants to prevent abscess formation.
  • The small bowel is returned to the lower abdomen and the omentum is draped over the appendiceal stump.
  • The laparoscope is placed back into one of the midline ports, and the remaining ports are removed under direct visualization to ensure hemostasis at the anterior abdominal wall.
  • The 5-mm ports do not require fascial closure, but the fascia of the supraumbilical port should be closed with absorbable sutures.
  • The skin is closed with monofilament suture or skin adhesive.
Postoperative Care
  • Patients should be advanced to a regular diet as tolerated and discharged home when they can tolerate oral intake and manage pain with oral medication only.
Potential Complications
  • Injury to bowel or other adjacent structures.
  • Intra-abdominal abscess.
  • Superficial wound infection (more common with open appendectomy).
  • Colonic fistula.
Pearls and Tips
  • It is useful to place the incision where the patient's pain is the greatest or where preoperative imaging has identified the appendix. This is particularly important in pregnant patients, as the appendix may be in an atypical location.
  • Conversion to an open procedure should be considered if visualization or dissection is difficult during laparoscopic appendectomy.
References
Andersen BR, Kallehave FL, Andersen HK. Antibiotics versus placebo for prevention of postoperative infection after appendicectomy. Cochrane Database Syst Rev. 2005;3: CD001439.
Doria AS, Moineddin R, Kellenberger CJ, et al. US or CT for diagnosis of appendicitis in children and adults? A meta-analysis. Radiology. 2006;241:83–94.[PubMed: 16928974] [Full Text]
Jones PF. Suspected acute appendicitis: trends in management over 30 years. Br J Surg. 2001;88:1570–1577.[PubMed: 11736966] [Full Text]
Sauerland S, Lefering R, Neugebauer EA. Laparoscopic versus open surgery for suspected appendicitis. Cochrane Database Syst Rev. 2004;4:CD001546.