Data from Buchwald H: Consensus Conference Panel: Consensus conference statement: Bariatric surgery for morbid obesity: Health implications for patients, health professionals, and third-party payers. Surg Obes Relat Dis 1:371–381, 2005.

PREOPERATIVE EVALUATION

A thorough preoperative assessment aimed at identifying modifiable risk factors is mandatory before bariatric surgery.

I. Cardiovascular: A preoperative electrocardiogram should be obtained for men older than 40 years, women older than 50 years, or patients with known coronary artery disease, diabetes mellitus, hypertension, obstructive sleep apnea, or arrhythmias. Patients with multiple cardiac risk factors should also undergo stress testing when possible. Unfortunately, this is not always feasible because most patients cannot tolerate even moderate exercise and thallium stress testing is inaccurate in patients with a BMI of more than 30. When available, transesophageal dobutamine stress echocardiogram is often the optimal study. In patients found to be at moderate or high cardiovascular risk, perioperative β-blockade may be recommended, although no study has yet demonstrated a benefit in this population.

II. Pulmonary: Between 40% and 80% of patients undergoing bariatric surgery have obstructive sleep apnea. Generally, patients should undergo preoperative sleep studies. If obstructive sleep apnea is shown, 4 weeks of CPAP or bilevel positive airway pressure (biPAP) is required before surgery. Long-standing OSA or reactive airway disease (also associated with obesity) can lead to pulmonary hypertension, which substantially increases operative risk. Systolic pulmonary artery pressures of greater than 50 mm Hg are a contraindication to surgery.

III. Psychiatric: More than 50% of candidates for bariatric surgery take psychotropic medication, most often for depression. The presence of inadequately treated psychiatric conditions has been correlated with inadequate weight loss and dissatisfaction after surgery. A structured interview with a psychologist or psychiatrist using a validated questionnaire, such as the Weight and Lifestyle Inventory or the Beck Depression Inventory, is recommended.

IV. Gastrointestinal: Nonalcoholic steatohepatitis (NASH) and cirrhosis are present in 40% and 2% of the severely obese population, respectively. Hepatic compromise is a contraindication to surgery, and liver function tests should, therefore, be obtained for all surgical candidates. Because of the high rate of postoperative cholelithiasis, some surgeons advocate screening for gallstones with a right upper quadrant ultrasound and, if the study is positive, removal of the gallbladder at the time of bariatric surgery.

V. Educational: Bariatric surgery results in the loss of 60% of excess body weight in most individuals, but requires extensive lifestyle changes postoperatively. Many patients have unrealistic expectations and require preoperative education. Postoperative referral to a support group may also be beneficial.

Does your patient have obesity-related comorbidities?

COMPONENTS OF THE PROCEDURE AND APPLIED ANATOMY

Preoperative Considerations

I. Sequential compression devices should be applied before the induction of anesthesia to prevent deep vein thrombosis (DVT). Some centers advocate preoperative treatment with subcutaneous heparin as well.

II. More than 50% of obese patients have gastroesophageal reflux disease. Supine positioning increases intra-abdominal pressure and the risk of aspiration during intubation. Intubation with the head of the table elevated at 15 degrees to 20 degrees is often preferred to decrease this risk.

III. Prophylactic antibiotics are administered before skin incision.

IV. A urinary catheter is placed to allow for continuous urine output monitoring.

V. A nasogastric tube is inserted to decompress the stomach.

Patient Positioning and Preparation

I. The patient is placed in the supine position with the arms extended. Pressure points are padded to prevent necrosis. Additionally, buttresses are constructed under the arms to minimize the amount of traction placed on the torso and to decrease the risk of brachial plexopathies.

II. The sterile preparation should extend to the nipples superiorly, to the pubis inferiorly, and to the posterior axillary lines laterally.

ALL PRESSURE POINTS SHOULD BE PADDED TO AVOID PRESSURE NECROSIS.

Roux-en-Y Gastric Bypass

Roux-en-Y gastric bypass (Fig. 9-1) has three major components: (1) construction of the gastric pouch, (2) division of the small bowel and creation of the Roux limb, and (3) creation of an anastomosis between the gastric pouch and jejunum (gastojejunostomy). Approaches to gastric bypass include: (1) laparoscopic, (2) hand-assisted laparoscopic, and (3) open. Specific techniques related to port placement and incisions for each approach are discussed first, followed by a discussion of the components of the procedure common to all three.

Figure 9-1 Roux-en-Y gastric bypass.

(From Kendrick ML, Dakin GF: Surgical approaches to obesity. Mayo Clin Proc 81[10 Suppl]:S18–S24, 2006.)

I. Laparoscopic Approach: Six ports are required for gastric bypass, including a camera port, two ports for the primary surgeon, a port for a liver retractor, and two ports for the assistant (Fig. 9-2).

B. The remaining ports are inserted under laparoscopic visualization.

II. Hand Assist: A hand port can replace one of the surgeon’s instrument ports (typically, the left-sided port) to allow for increased intracorporeal needle control and a faster operative time.

A. The first port is inserted as described under “Laparoscopic Approach,” and CO₂ is insufflated into the abdomen.

B. A left-sided vertical paramedical incision (i.e., an incision adjacent to the midline) is made. The incision should be just large enough to accommodate the surgeon’s hand.

C. The subcutaneous tissues are divided to expose the rectus fascia. The anterior rectus sheath, rectus muscle, posterior rectus sheath, and peritoneum are sequentially opened.

D. A laparoscopic system (GelPort) is inserted into the incision; this functions as a one-way valve, allowing the surgeon to place a hand into the abdomen without the loss of pneumoperitoneum.

E. The remaining ports are placed under laparsocopic visualization. A static liver retractor port is often unnecessary because the surgeon’s hand can retract the liver.

III. Open

A. An upper midline incision is made, extending from the xiphoid process toward the umbilicus. Generous incisions are sometimes required to allow for adequate exposure in severely obese patients.

B. The incision is carried down to the fascia through the fat.

C. The midline raphe is identified and incised sharply, preferably near the top of the incision over the liver to minimize the risk of inadvertent injury to abdominal viscera. Once the peritoneum is opened, the fascia is lifted up and the incision is extended.

IV. Exposure and Dissection

A. The liver is examined for signs of cirrhosis or fatty replacement indicative of NASH. The gallbladder is inspected for the presence of gallstones or sludge.

B. The mobility of the small bowel is assessed and the ligament of Treitz is identified.

V. Construction of the Biliopancreatic Limb: The jejunum is divided approximately 40 cm distal to the ligament of Treitz. The specific length of the resultant limb is less important than is the mobility of the bowel at the site of division. The distal bowel must reach the stomach without tension to allow for subsequent construction of an end-to-side gastrojejuostomy.

VI. Construction of the Jejunojejunostomy and Roux Limb

A. A side-to-side anastomosis is created between the proximal end of the divided jejunum and the jejunum 120 to 150 cm beyond the stapled division (Fig. 9-3).

B. The length of the resulting bypassed limb directly influences the degree of malabsorption after surgery. Some surgeons vary the length of the bypassed limb based on BMI (e.g., creating longer limbs in larger patients).

Figure 9-2 Trocar placement for laparoscopic Roux-en-Y gastric bypass.

(From Townsend CM, Beauchamp RD, Evers BM, Mattox KL [eds]: Sabiston Textbook of Surgery: The Biological Basis of Modern Surgical Practice, 17th ed. Philadelphia, Saunders, 2004.)

Figure 9-3 Side-to-side jejunojejunostomy.

(From Townsend CM, Beauchamp RD, Evers BM, Mattox KL [eds]: Sabiston Textbook of Surgery: The Biological Basis of Modern Surgical Practice, 17th ed. Philadelphia, Saunders, 2004.)

Carbohydrates and protein are primarily absorbed in the duodenum and the first 100 cm of the jejunum.

VII. Construction of the Gastric Pouch and Gastrojejunostomy

A. The patient is placed in the steep Trendelenburg position, allowing the small bowel and omentum to fall away from the diaphragmatic hiatus.

B. The left lobe of the liver is retracted laterally to expose the stomach.

C. The stomach is grasped and retracted toward the feet to expose the gastroesophageal junction.

D. The pars flaccida, the avascular portion of the gastrohepatic ligament, is identified and divided to expose the lesser sac.

E. Dissection is carried posteriorly around the back wall of the stomach toward the spleen.

F. Once the stomach has been adequately mobilized, a stapler is used to partition the gastric pouch from the remainder of the stomach. Typically, the staple line extends from the angle of His to the midportion of the lesser curve. The nasogastric tube is withdrawn into the esophagus during the creation of the pouch.

G. The Roux limb is brought up to the stomach either anterior or posterior to the transverse colon. If it is brought up posteriorly (i.e., retrocolic), a defect is created in the transverse colon mesentery through which the limb is passed.

H. A hole is made in the anterior wall of the gastric pouch, and an anastomosis is created between the gastric pouch and the distal end of the divided small bowel.

VIII. Testing of the Anastomosis and Closure

A. Once the procedure is complete and hemostasis is confirmed, the gastrojejunostomy may be inspected endoscopically. Any apparent leaks are repaired with interrupted stitches.