Eric J. DeMaria, MD, FACS
Professor of Surgery, Duke University School of Medicine, and Vice Chair and Chief of Network General Surgery and Director of EndoSurgery and Bariatric Surgery, Duke University Medical Center
Christopher J. Myers, MD
Minimally Invasive Surgery Fellow, Duke University School of Medicine
10.2310/7800.2008.S05C07
It is clear that severe obesity is associated with a significant increase in morbidity1 and a decreased life expectancy.2 Morbid obesity—defined as (a) a body weight that exceeds the ideal body weight by 100 lb or more or (b) a body mass index (BMI) greater than 35 kg/m2—has been shown to have a significant genetic basis.34 To date, attempts to manage morbid obesity with medical weight reduction programs have met with an unacceptably high incidence of recidivism.5 The approach that has had the greatest and longest-lasting success in achieving weight loss is bariatric surgery.
Preoperative Evaluation
Many surgeons are afraid to operate on the morbidly obese patient because they presuppose a marked increase in perioperative morbidity and mortality. It is now possible, however, to stratify the mortality risk for patients undergoing gastric bypass (GBP) by using a scoring system known as the Obesity Surgery Mortality Risk Score (OS-MRS), which includes five independent variables that can be identified preoperatively: (1) BMI greater than or equal to 50 kg/m2, (2) male gender, (3) hypertension, (4) pulmonary embolus risk (including previous thrombosis, pulmonary embolus, inferior vena cava [IVC] filter, right-side heart failure, and obesity hypoventilation syndrome [OHS]), and (5) patient age greater than or equal to 45 years. These factors were associated with a greater 90-day mortality in a prospective study of 2,075 patients who underwent GBP at a single institution,6 which was the basis for the initial proposal of this scoring system. The OS-MRS was subsequently validated in a multicenter study involving four institutions and 4,431 patients.7 With the presence of each variable equal to 1 point, each patient’s potential score ranged from 0 to 5. Patients with a score of 0 or 1 had a low mortality risk (group A; mortality, 0.2%); those with a score of 2 or 3 had an intermediate mortality risk (group B; mortality, 1.1%); and those with a score of 4 or 5 had a high mortality risk (group C; mortality, 2.4%). These findings suggest that the OS-MRS is a valuable tool that can be effectively used to stratify risk and facilitate surgical decision making and patient discussion regarding bariatric surgery.
Although the morbidly obese patient is certainly at greater risk, this risk can be markedly reduced by paying careful attention to detail in preoperative and postoperative care. The increased risks encountered in these patients include wound infection, dehiscence, thrombophlebitis, pulmonary embolism (PE), anesthetic calamities, acute postoperative asphyxia in patients with obstructive sleep apnea syndrome (SAS), acute respiratory failure, right ventricular or biventricular cardiac failure, and missed acute catastrophes of the abdomen (e.g., anastomotic leakage). The ensuing discussion begins by focusing on issues that the surgeon should carefully consider when operating on an extremely overweight patient.
Morbidity Associated with Central Fat Deposition
Much has been written about the increased health risks inherent in central (android) fat deposition as compared with peripheral (gynoid) fat deposition. It is thought that in the former, the increased metabolic activity of mesenteric fat is associated with increased metabolism of amino acids to sugar, which leads to hyperglycemia and hyperinsulinism. Hyperinsulinism gives rise to increased sodium absorption and hypertension. Furthermore, central obesity has been linked to hypercholesterolemia. Hence, these patients have a significantly higher incidence of diabetes, hypertension, hypercholesterolemia, and gallstones8—which explains the higher mortality of the apple distribution of body fat in comparison with the pear distribution. In the past, fat distribution was measured on the basis of the waist-to-hip ratio; however, computed tomographic scanning has shown that abdominal circumference is a more accurate measurement of central fat distribution.9 Morbidly obese women have significantly increased intra-abdominal pressure (IAP), and this increase is associated with stress and urge overflow urinary incontinence.10 With weight loss comes a significant decrease in bladder pressure and correction of incontinence. IAP, as reflected in bladder pressure, appears to be closely correlated with sagittal abdominal diameter and waist circumference but not with waist-to-hip ratio (many morbidly obese patients have both central and peripheral obesity). The increased IAP associated with central obesity may give rise to other comorbid factors as well, including venous stasis ulcers, OHS [see Respiratory Insufficiency of Obesity, below], gastroesophageal reflux, and inguinal and incisional hernias.
Respiratory Insufficiency of Obesity
Obese patients are at risk for respiratory difficulties, which may be present before operation or may be exacerbated by an operation. The term pickwickian syndrome (which derives from The Posthumous Papers of the Pickwick Club, by Charles Dickens) was resurrected from the late 1800s to describe a morbidly obese 52-year-old man who fell asleep in a poker game while holding a hand containing a full house.11 He was taken to the hospital by friends who presumed he was ill. The pickwickian syndrome is now known to comprise two pulmonary syndromes associated with morbid obesity: SAS and OHS.12
Sleep Apnea Syndrome
SAS is a potentially fatal complication of morbid obesity. A diagnosis of SAS should be suspected when there is a history of loud snoring, frequent nocturnal awakening with shortness of breath, and daytime somnolence. It is estimated that 2% of middle-aged women and 4% of middle-aged men in the US workforce have SAS, and the incidence is markedly higher in the severely obese.13 Patients will often admit to falling asleep while driving and waking up with their car on the road’s median strip or bumping its guardrail. It is extremely important that trauma surgeons be aware of the relation between obesity and somnolence should a morbidly obese patient be seen in the emergency department after an automobile accident in which he or she fell asleep at the wheel. Patients with SAS suffer from repeated attacks of upper airway obstruction during sleep. The cause is probably related to a large, fat tongue, as well as to excessive fat deposition in the uvula, pharynx, and hypopharynx. The normal genioglossus reflex is depressed, but this depression may be secondary to the excessive weight of the tongue. These patients are notorious snorers. As a result of inadequate stage IV and rapid eye movement (REM) sleep, they are markedly somnolent during the day.
Patients with SAS are at high risk for acute upper airway obstruction and respiratory arrest when undergoing an operation and general anesthesia. Therefore, any patients with suspected SAS should undergo preoperative polysomnography at a sleep center to confirm the diagnosis. Medications are usually ineffective. Stimulants, such as methylphenidate hydrochloride (Ritalin), should not be used. If a patient has a respiratory disturbance index (RDI) greater than 25—indicating more than 25 apneic or hypopneic episodes per hour of sleep—or has cardiac dysrhythmias in association with apnea, treatment by nocturnal nasal continuous positive airway pressure (nasal CPAP) should be provided. With this technique, air flowing through a nasal mask against a constant airway resistance enters the nasal pharynx and pushes the tongue forward to prevent recurrent obstruction.14 The pressure can be adjusted for each patient. Unfortunately, many patients cannot tolerate the device, because it is cumbersome and noisy and tends to dry out the upper airway, though dryness can be prevented with an inexpensive room humidifier. If the patient has severe SAS with an RDI greater than 40 and does not respond with elimination of the apneic episodes or cannot tolerate nasal CPAP, a tracheostomy should be considered. An extra-long tracheostomy tube is usually necessary because of the depth of the trachea in the morbidly obese patient.
Obesity Hypoventilation Syndrome
OHS is a condition associated with morbid obesity in which a person suffers from hypoxemia and hypercapnia when breathing room air while awake but resting.15 Spirometry reveals decreases in forced vital capacity, residual lung volume, expiratory reserve volume, functional residual capacity, and maximum minute volume ventilation, usually without obstruction of airflow [see Figure 1]. The most profound decrease is that in expiratory reserve volume; it is probably secondary to increased IAP and a high-riding diaphragm. Thus, these patients have a restrictive rather than an obstructive pulmonary disease. The decreased expiratory reserve volume implies that many alveolar units are collapsed at end-expiration, which leads to perfusion of unventilated alveoli, or shunting. Patients with OHS often are heavy smokers or have additional pulmonary problems, such as asthma, sarcoidosis, idiopathic pulmonary fibrosis, or recurrent PE. One study of patients who underwent operation for morbid obesity showed no statistically significant difference in weight between those who had OHS and those who did not.12
Chronic, severe hypoxemia is associated with three complications that put patients with OHS at risk: polycythemia, pulmonary arterial vasoconstriction, and pulmonary hypertension. The polycythemia further increases the already significant risk of venous thrombosis and PE. If the hemoglobin (Hb) concentration is 16 g/dl or greater, phlebotomy to a concentration of 15 g/dl should be performed to reduce the postoperative risk of venous thrombosis. If the pulmonary arterial pressure (PAP) is 40 mm Hg or higher, consideration should be given to prophylactic insertion of an IVC filter because of the high risk of a fatal pulmonary embolism in these patients.16 Placement of an IVC filter can be a challenge because the appropriate landmarks cannot be identified in the operating room with fluoroscopy. It is necessary, before operation, to tape a quarter to the patient’s back over the second lumbar vertebra with the aid of fixed radiographs and then, during operation, to aim for the quarter with the insertion catheter, using fluoroscopy. Because these patients are usually too heavy for angiography tables, the filter usually cannot be inserted percutaneously in the radiology department.
Chronic hypoxemia also leads to pulmonary arterial vasoconstriction and severe pulmonary hypertension and eventually to right-side heart failure or cor pulmonale with neck vein distention, tricuspid valvular insufficiency, right upper quadrant tenderness secondary to acute hepatic engorgement, and massive peripheral edema.1718 Such patients may also have a significantly elevated pulmonary artery wedge pressure (PAWP), which suggests left ventricular dysfunction.17 Morbidly obese patients with a history of pulmonary disease or a BMI greater than 50 kg/m2 should have preoperative determinations of blood gas values. If arterial blood gas (ABG) measurement reveals severe hypoxemia (i.e., arterial oxygen tension [Pao2] f55 mm Hg), severe hypercapnia (arterial carbon dioxide tension [Paco2] g47 mm Hg), or both, the patient should undergo Swan-Ganz catheterization. If the PAWP is 18 mm Hg or greater, intravenous furosemide should be administered for diuresis before elective operation. However, some patients may require a high ventricular filling pressure. A low cardiac output and hypotension may follow diuresis, necessitating volume reexpansion.
It is highly probable that some of the elevated PAP and PAWP measurements are caused by the increased IAP in the morbidly obese patient [see Figure 2]).1920 The high IAP leads to an elevated diaphragm, which in turn increases intrapleural pressure and thereby PAP and PAWP; if the pleural pressure is measured with an esophageal transducer, the transmyocardial pressure can be estimated. For this reason, these patients may require a markedly elevated PAWP to maintain an adequate cardiac output, and excessive diuresis may lead to hypotension. The same reasoning may be applied to a patient with a distended abdomen resulting from peritonitis and pancreatitis in whom what seem to be unusually high cardiac filling pressures are necessary. Therefore, one must rely on relative changes in cardiac output in response to either volume challenge or diuresis to determine the optimal PAWP in morbidly obese patients.
Patients with OHS respond rapidly to supplemental oxygen. However, oxygen administration is occasionally associated with significant CO2 retention, which necessitates intubation and mechanical ventilation. Because their pulmonary disease is restrictive rather than obstructive, these patients are usually easy to ventilate without high peak airway pressures. ABG measurements need not return to normal values before extubation; it is only necessary that they return to their preoperative values. These values are achieved early after laparoscopic procedures and, on average, 4 days after major open upper abdominal operations, when patients experience a decrease in incisional pain.21
It is important to emphasize that morbidly obese patients, especially those with respiratory insufficiency, should be placed in the reverse Trendelenburg position to maximize diaphragmatic excursion and to increase residual lung volume.22 These patients will often complain of air hunger and respiratory distress when they lie supine. So-called breaking of the bed at the waist may exacerbate the problem by pushing the abdominal contents into the chest, thereby raising the diaphragm and further reducing lung volumes. Placing these patients in the leg-down position may predispose them to venous stasis, phlebitis, and PE; this tendency should be offset with intermittent venous compression boots [see Thrombophlebitis, Venous Stasis Ulcers, and Pulmonary Embolism, below].23
Both SAS and OHS can be completely corrected with weight reduction after gastric operation for morbid obesity: the nocturnal apneas resolve, the Pao2 rises, and the Paco2 falls to normal as lung volumes improve.12
Cardiac Dysfunction
Morbidly obese patients are at significant risk for coronary artery disease as a result of an increased incidence of systemic hypertension, hypercholesterolemia, and diabetes. Because of this increased risk for cardiac dysfunction, preoperative electrocardiography should be performed on all obese patients 30 years of age or older.
Cardiac dysfunction in the morbidly obese patient is usually associated with respiratory insufficiency of obesity, especially OHS.11 An elevated PAP in these patients may be secondary to hypoxemia-induced pulmonary arterial vasoconstriction, to elevated left atrial pressures secondary to left ventricular dysfunction, or to a combination of these; it may also be secondary to the increased pleural pressures arising from an elevated diaphragm secondary to increased IAP.172023 It is unusual for morbidly obese patients without respiratory insufficiency to experience significant cardiac dysfunction in the absence of severe coronary artery disease. Morbidly obese patients often have systemic hypertension, which can aggravate left ventricular dysfunction; however, mild left ventricular dysfunction can be documented in many morbidly obese patients in the absence of systemic hypertension.2425 Circulating blood volume, plasma volume, and cardiac output increase in proportion to body weight.25 Massively obese patients may occasionally present with acute heart failure: it is reasonable to assume that the enormous metabolic requirements of such patients can present a greater demand for blood flow than the heart can provide. Vigorous diuresis often corrects such acute heart failure. Significant weight loss corrects pulmonary hypertension [see Figure 3], as well as the left ventricular dysfunction associated with respiratory insufficiency.1726
Thrombophlebitis, Venous Stasis Ulcers, and Pulmonary Embolism
Morbidly obese individuals have difficulty walking, tend to be sedentary, have a large amount of abdominal weight resting on their IVC, and have increased intrapleural pressure (which impedes venous return).1820 All of these conditions increase the tendency toward phlebothrombosis. Patients are most at risk when immobilized in the supine position for long periods in the OR. These patients have been shown to have low levels of antithrombin, which may increase their tendency toward venous thrombosis.27 It has also been suggested that starvation, particularly in the postoperative period, may be associated with high levels of free fatty acids, which may predispose to perioperative thrombotic complications.28 Patients with severe OHS often have a noticeably elevated PAP, which can lead to right-side heart failure and can increase the risk of venous stasis and thrombosis. Investigators have noted that patients with primary idiopathic pulmonary hypertension are at significant risk for fatal PE.13
The risk of deep vein thrombosis (DVT) increases with a prolonged operation or a postoperative period of immobilization, and it increases even further in the morbidly obese patient. Standard or low-molecular-weight heparin should be administered subcutaneously 30 minutes before operation and at appropriate intervals thereafter (depending on the type of heparin used) for at least 2 days or until the patient is ambulatory. Because respiratory function in the morbidly obese patient is greatly enhanced with the reverse Trendelenburg position, intermittent sequential venous compression boots should be used to counteract the increased venous stasis and the propensity for clotting. It is important that the intermittent venous compression boots be used before induction of anesthesia and throughout the operative procedure. Such boots are usually part of a standard preoperative protocol in gastric procedures for weight control; their use should not be unintentionally neglected in preparation for other elective or emergency procedures on morbidly obese patients. Patients with severe venous stasis disease (e.g., pretibial stasis ulcers or bronze edema) are at significantly increased risk for fatal PE.29 Prophylactic insertion of an IVC filter should be considered in these patients (as for patients with OHS and a high PAP). All patients should make every attempt to walk during the evening after operation. Bariatric surgery–induced weight loss will correct the venous stasis disease in most cases.29
Venous stasis ulcers can be quite difficult to treat in a thin person; they are almost impossible to cure in a patient with morbid obesity [see Figure 4]. The most important goal in the management of these ulcers is weight loss, which almost invariably leads to healing of the ulcer, probably as a result of decreased IAP.29
Gallstones
Approximately one third of morbidly obese patients either have had a cholecystectomy or may have had gallstones noted at the time of another intra-abdominal operative procedure (e.g., a gastric operation for morbid obesity). Preoperative evaluation of the gallbladder may be technically quite difficult in morbidly obese patients because ultrasonography may fail to visualize gallstones. Intraoperative ultrasonography is probably much more accurate. Should symptomatic gallstones be present in a patient undergoing a gastric procedure for obesity, the gallbladder should be removed if the surgeon judges it safe to perform this additional procedure. If placement of an adjustable gastric band is contemplated, the cholecystectomy should be undertaken first and the indwelling device placed only in the absence of intra-abdominal bile spillage during the procedure.
In past studies, rapid weight loss led to the development of gallstones in 25 to 40% of patients who underwent GBP. The risk of cholelithiasis in this setting can be reduced to 2% by administering ursodeoxycholic acid, 300 mg orally twice daily.30 Laparoscopic cholecsytectomy at the time of laparoscopic gastric bypass can be technically challenging; consequently, many surgeons prefer to take an expectant approach to the gallbladder rather than complicate the bariatric procedure with a simultaneous cholecystectomy (unless cholecystectomy is clearly indicated in a particular patient).
Pseudotumor Cerebri
Pseudotumor cerebri is an unusual complication of morbid obesity that is associated with benign intracranial hypertension, papilledema, blurred vision, headache, and elevated cerebrospinal fluid pressures.31 It has been our experience that patients with pseudotumor cerebri are not at any additional perioperative risk and that CSF need not be removed before anesthesia and major abdominal operations. There is some theoretical concern that gastrointestinal contamination during GBP may cause shunt infection in patients who have been previously treated with indwelling shunts to relieve elevated CSF pressures. Successful weight reduction cures pseudotumor cerebri.3233
Degenerative Osteoarthritis
Degenerative osteoarthritis of the knees, hips, and back is a common complication of morbid obesity. Weight reduction alone may greatly reduce the pain and immobility that afflict these patients. In some cases, the damage may be so extensive that a total joint replacement is desirable; however, joint replacement in patients who weigh more than 250 lb is associated with an unacceptable incidence of loosening.34 Weight reduction by means of a gastric bariatric operation may be the most sensible initial approach, to be followed by joint replacement after weight loss if pain and dysfunction persist.
Operative Planning
Anesthesia in Patients with Respiratory Insufficiency
Morbidly obese patients can be intimidating to the anesthesiologist because they are at significant risk for complications from anesthesia, especially during induction. The risk is particularly great for obese patients with respiratory insufficiency. An obese patient often has a short, fat neck and a heavy chest wall, which make intubation and ventilation a challenge. If endotracheal intubation proves difficult, however, such a patient can usually be well ventilated with a mask. Awake intubation can be performed, with or without fiberoptic aids, but is quite unpleasant and rarely necessary.
It is extremely important that at least two anesthesia personnel be present during induction and intubation for patients with respiratory insufficiency of obesity. An oral airway is inserted after muscle paralysis with succinylcholine and sodium pentobarbital induction. One person elevates the jaw, hyperextends the neck, and ensures a tight fit of the mask, using both hands. To ensure adequate oxygen delivery, a second person compresses the ventilation reservoir bag, using two hands because of the resistance to air flow from the poorly compliant, heavy chest wall. After ventilation with 100% oxygen for several minutes, intubation is attempted. If difficulties are encountered within 30 seconds, the steps above should be repeated until the patient has been successfully intubated. A volume ventilator is required during operation. Placing the patient in the reverse Trendelenburg position expands total lung volume and facilitates ventilation22; however, the reverse Trendelenburg position increases lower-extremity venous pressure and therefore mandates the use of intermittent sequential venous compression boots. It is helpful to monitor blood gases through a radial arterial line or a digital pulse oximeter.
Laparoscopic Versus Open Approach to Bariatric Surgery
Bariatric surgical procedures, like most other general surgical procedures, have undergone a transition from an open approach to one that places more emphasis on minimally invasive or laparoscopic techniques. Laparoscopic GBP was first described in 1994 and became widely accepted in 1999, though it was not until 2004 that, according to a national audit of bariatric surgery performed at academic centers, the number of laparoscopic GBP procedures performed exceeded the number of open GBP procedures.
At present, the laparoscopic approach to GBP is favored because it achieves a comparable degree of weight loss while possessing some notable advantages over its open counterpart.21 Open GBP is performed through an upper midline incision, whereas laparoscopic GBP is performed through five or six small incisions. Abdominal wall retractors and mechanical retraction of the abdominal viscera, which are necessary for adequate exposure during an open procedure, are not required during a laparoscopic procedure, which makes use of gas insufflation (for pneumoperitoneum) and the effects of body positioning and gravity to facilitate intraoperative exposure. With the elimination of the large surgical incision and mechanical retraction, the laparoscopic GBP patient experiences less operative trauma, less postoperative pain, and fewer wound-related complications. In addition, laparoscopic GBP yields less impairment of immediate postoperative pulmonary function and a lower systemic stress response. A 2007 study of 22,422 patients who underwent Roux-en-Y GBP for treatment of morbid obesity compared the outcomes of laparoscopic procedures (n=16,357) with those of open procedures (n=6,065).35 The mean length of hospital stay was significantly lower in the laparoscopic group (2.7 days versus 4.0 days), as were the overall complication rate (7.4% versus 13.0%), the 30-day readmission rate (2.6% versus 4.7%), the in-hospital mortality (0.1% versus 0.3%), and the mean cost ($13,743 versus $14,585 [US]).
Choice of Surgical Procedure
The gastric operations performed for morbid obesity include both GBP procedures and gastric restrictive procedures (i.e., gastroplasty and gastric banding). Randomized, prospective trials have conclusively shown that GBP is as effective for weight control as the malabsorptive jejunoileal (JI) bypass is, while resulting in significantly fewer complications.3637 JI bypass is associated with a substantial incidence of both early complications (e.g., acute cirrhosis, electrolyte imbalance, and fulminant diarrhea)38 and late complications (e.g., cirrhosis, interstitial nephritis, arthritis, enteritis, nephrocalcinosis, and recurrent oxalate renal stones).39 If evidence of cirrhosis, renal failure secondary to interstitial nephritis, or other complications mandates reversal of a JI bypass, the patient, if not extremely ill, should be converted to a GBP; otherwise, all the lost weight is sure to be regained, and the obesity-related comorbidity will return. Admittedly, however, some patients have done well after JI bypass and do not need to have the operation reversed.
Several randomized, prospective trials have found that horizontal gastroplasty yields poorer results than GBP.40-42 Failure of horizontal gastroplasty has generally been attributed to technical causes (e.g., enlargement of the proximal pouch or the stoma or disruption of the staple line). Vertical banded gastroplasty (VBG) was developed in the hope that it would solve these technical problems and yield weight loss comparable to that seen after GBP without incurring the significant risk of iron, calcium, and vitamin B12 deficiencies associated with GBP. In the 1990s, a procedure known as adjustable silicone gastric banding was developed, which involved placement of a restrictive ring around the proximal stomach to create a small gastric pouch. In this restrictive procedure, which can be done laparoscopically in the vast majority of patients, weight loss can be enhanced and vomiting minimized by adjusting the ring diameter via transcutaneous access to the subcutaneous reservoir.
Although VBG and, presumably, other restrictive procedures appear to be excellent from a technical point of view,43 multiple randomized, prospective trials have found such approaches to be significantly less effective than standard GBP. In one comparison trial, patients addicted to sweets lost much more weight after GBP than after VBG because they experienced symptoms of dumping syndrome when ingesting sweets.44 The failure rate was high after VBG because these patients experienced no difficulties when eating candy or drinking nondietetic sodas. Subsequent randomized, prospective trials confirmed the superiority of GBP.4546 Furthermore, maintenance of successful weight loss after GBP appears to continue for as long as 14 years after operation: in the average patient, weight loss amounts to about two-thirds of excess weight at 1 to 3 years after operation, three-fifths at 5 years, and more than half in years 5 through 10.4748 It has been suggested that standard (i.e., proximal) GBP will fail in 10 to 15% of patients because these patients will frequently nibble on high-fat snacks (e.g., corn chips, potato chips, and buttered popcorn). Such patients may have to be converted to a combined restrictive and malabsorptive procedure, such as partial biliopancreatic diversion (BPD).49
The original BPD procedure involves hemigastrectomy and anastomosis of the distal 250 cm of intestine to the stomach; the bypassed small intestine is reanastomosed to the ileum 50 cm from the ileocecal valve. BPD with duodenal switch is a variant of the original procedure in which a linear gastric tube based on the lesser curvature is created (sleeve gastrectomy), with the pylorus left intact, and an ileal Roux limb is brought up for anastomosis to the proximal duodenum. BPD has been associated with a high incidence of deficiencies of fat-soluble vitamins, hypocalcemia-induced osteoporosis, and protein-calorie malnutrition.50 These nutritional deficiencies may be more common in the United States, where fat intake is high, than in many other countries. In Italy, for example, starch intake (as in pasta) probably outstrips fat intake; still, a number of Italian patients have had to be readmitted for parenteral nutrition and extension of the common absorptive intestinal tract because of refractory malnutrition. In some patients, it might be possible to convert a failed proximal GBP into a modified BPD with a 150 cm absorptive ileal limb (a procedure often referred to as distal GBP); however, these patients must also be monitored carefully for deficiencies of fat-soluble vitamins, for osteoporosis, and for malnutrition.
Superobese patients—defined as those whose weight is 225% of ideal body weight or greater or whose body mass index (BMI) is 50 kg/m2 or higher—will lose, on average, only about half of their excess weight, rather than two-thirds, after standard GBP. In these patients, a 150 cm proximal Roux-en-Y procedure (so-called long-limb GBP [see Open Proximal Gastric Bypass, Operative Technique, below]) may increase weight loss in the first few years after operation without causing an increase in nutritional complications.51
In choosing the appropriate surgical approach, it is important to take into account the tremendous surgical revolution that laparoscopy has brought about in the treatment of morbid obesity. Now that every operation performed to treat obesity can be done laparoscopically, laparoscopic bariatric surgery is not only common but, in many centers, predominant. For this reason, as well as because laparoscopic obesity treatment requires advanced technical skills, minimally invasive bariatric procedures have become a cornerstone of training for surgeons now learning laparoscopic surgery.
Vertical Banded Gastroplasty
Operative Technique
The first step in VBG is to make a circular stapled opening in the stomach 5 cm from the esophagogastric junction. A 90 mm bariatric stapler with four parallel rows of staples is then applied once between this opening and the angle of His. (At this point, according to Mason, the originator of the procedure, the volume of the pouch should be measured by means of an Ewald tube placed by the anesthetist; ideally, pouch volume should be 15 ml.)
Next, a strip of polypropylene mesh is wrapped around the gastrogastric outlet on the lesser curvature and sutured to itself—but not to the stomach—in such a way as to create an outlet with a circumference of 5 cm for the small upper gastric pouch [see Figure 5a]. Some surgeons have used a stomal outlet 4.5 cm in circumference, but this smaller outlet has not led to better weight loss; in fact, many patients with the 4.5 cm outlet exhibit maladaptive eating behavior, drinking high-calorie liquids because meat tends to get caught in the small stoma.
Silastic ring gastroplasty [see Figure 5b] is a variant of VBG that uses a vertical staple line and a stoma reinforced with Silastic tubing.
Complications
Complications of VBG include erosion of the polypropylene mesh used to restrict the gastroplasty stoma into the gastric lumen, enlargement of the pouch, stomal stenosis, reflux esophagitis, and mild vitamin deficiencies.52 To date, mesh erosion has been infrequently observed after VBG. Pouch enlargement is fairly common with horizontal gastroplasty but is much less likely to occur with VBG, in which the vertical staple line is placed in the thicker, more muscular part of the stomach. In addition, stomal diameter remains fixed with the mesh band. If mesh erosion, pouch enlargement, stomal stenosis, disabling GI reflux, or recurrent vomiting occurs, it is probably best to convert the patient to GBP. In particular, patients with a Silastic ring VBG may exhibit intractable vomiting of solid foods with no evidence of mechanical obstruction. In our experience, conversion of these patients to GBP yields good results and eliminates the vomiting problem. Finally, vitamin deficiencies can usually be prevented by having VBG patients take a standard multivitamin daily for life.
Laparoscopic Adjustable Gastric Banding
Gastric banding is another form of gastroplasty, in which a synthetic band is placed around the stomach just below the esophagogastric junction. In several series, gastric banding has yielded markedly variable results with respect to achievement of weight loss. Furthermore, it has been associated with slipping or kinking of the banded stoma, obstruction at the band, and intractable vomiting.
Laparoscopic adjustable gastric banding (LAGB) is significant advance over open gastric banding procedures, primarily because of the adjustability of the band. Open gastric banding procedures have used a variety of materials to constrict the gastric lumen and carry a recognized risk of postoperative nausea and vomiting that do not respond to any treatment short of reoperation. The adjustable gastric bands available for use in LAGB [see Figure 6] are silicone devices with an inflatable reservoir that can be inflated or deflated postoperatively through a subcutaneous port placed deep in the abdominal wall for percutaneous access. Saline is injected into or withdrawn from the reservoir to adjust gastric luminal diameter. These diameter changes can be measured by means of barium contrast evaluation, but currently, most adjustments are made without x-ray guidance. If intractable vomiting develops, saline can be removed from the band to alleviate the problem; similarly, if the patient fails to lose weight after operation, additional saline may be injected into the band to narrow the gastric lumen further.
Use of the laparoscopically placed adjustable gastric band (Lap-Band, Allergan Corp., Irvine, CA) was approved by the US Food and Drug Administration in June 2001. Key data on safety and effectiveness were provided by a prospective, single-arm trial involving 299 patients at eight centers in the United States. In this study, patients who completed 36 months of follow-up achieved a mean reduction in BMI of 39% and a mean overall loss of 18% of baseline body weight. However, 28% of patients lost less than 10% of their initial body weight (a clear definition of failed weight loss). More than half (62%) of these patients lost more than 25% of their excess weight. Most patients (76%) experienced at least one adverse event, and 33% of patients required removal of the banding system.
Subsequent studies have yielded similar results. A 2007 review of two multicenter prospective, single-arm surgical trials evaluating a total of 485 patients who underwent placement of a gastric band (92% laparoscopically) between June 1995 and June 2001 suggested that the procedure was as effective as was previously believed.53 The change in mean BMI (kg/m2) was 38 to 47% at 1 year and 39% at 3 years. The percentage of initial body weight lost was 17 to 18% at 1 year and 18% at 3 years. Similarly, most patients (66 to 76%) experienced upper GI symptoms at 1 year. In one of the trials, 33% of the patients (96/292 patients) had had their bands removed at 9 years, either because of complications or because of inadequate weight loss.53
In a 2006 study comparing outcomes, LAGB proved to be just as safe as, cheaper than, and almost as effective as laparoscopic Roux-en-Y gastric bypass (LRYGB).54 This retrospective review of 590 bariatric procedures (120 LRYGB, 470 LAGB) performed between November 2000 and July 2004 suggested that both operating time and duration of hospitalization were significantly shorter in LAGB patients. Complication rates and reoperation rates were similar in the two groups. Patients who underwent LRYGB initially lost weight more rapidly: their mean percentage of excess body weight lost (%EBWL) was 65% during postoperative year 1, compared with 39% for LAGB patients. Thereafter, weight loss slowed, remaining nearly unchanged at 3 years (63%). Patients who underwent LAGB initially lost weight more slowly, but the ongoing weight loss was continuous, eventually approaching that of LRYGB. At 3 years, the %EBWL for LAGB patients was 55%.
Operative Technique
LAGB is performed by using a five-port technique. Initial abdominal access is obtained via a supraumbilical trocar, and the remaining ports are placed sequentially along the right and left costal margins. The liver is retracted via the subxiphoid port, and the proximal stomach is visualized with a laparoscope inserted through the umbilical port.
Subsequent steps are done according to the pars flaccida technique. A retrogastric tunnel for band insertion is created at the posterior confluence of the diaphragmatic crura in a plane of dissection that is easily developed with minimal blunt dissection after electrocauterization of the peritoneal membrane. This tunnel is placed cephalad to the posterior peritoneal reflection, so that the free space of the lesser sac posterior to the stomach is not entered. Additional dissection is then carried out laterally at the angle of His to open the peritoneum and start clearing a plane behind the proximal stomach.
A specially designed implement is inserted behind the stomach from the lesser curvature to the angle of His and used to grasp the tubing of the banding device and pull it around the stomach. The banding device is then locked into place at the chosen location on the proximal stomach [see Figure 7]. Gastrogastric sutures are placed to create a tunnel of stomach overlying the banding device—but not the buckle—so as to hold the device in position. The band tubing is brought through the left midclavicular trocar port, which is placed via the left midclavicular line subcostal trocar incision and fixed to the abdominal wall fascia with sutures. The tubing is connected to the reservoir, which is filled with saline.
Troubleshooting
It is essential to place the band properly during the initial procedure. The results to date suggest that the proximal pouch must be very small to optimize weight loss. In addition, proper placement minimizes—though it does not eliminate—the risk of band slippage and the complications thereof.
Several techniques have been suggested for posterior fixation of the band, but they are more difficult than anterior fixation techniques. With the pars flaccida technique, posterior fixation of the band is not necessary to prevent band slippage. Anterior fixation, however, is routinely performed, with interrupted sutures of nonabsorbable material placed between the distal and the proximal stomach to allow tissue to be apposed over the band and held in place.
Although LAGB appears easier than many of the procedures done to treat obesity, there is a definite learning curve. A number of surgical misadventures have been reported, including gastric perforation, splenic injury, and malpositioning of the band.
Complications
Band slippage (anterior, posterior, or concentric) may occur even after proper placement, resulting in intolerance of oral intake and vomiting. Such complaints are an indication for an upper GI series, which usually reveals dilatation of the proximal pouch and rotation of the band [see Figure 8]. Initial treatment consists of evacuating all saline from the band. Frequently, however, the proximal pouch does not return to its normal size, and symptoms recur or fail to resolve. Laparoscopic or open revision of the banding procedure is then required; if the patient also has not lost a sufficient amount of weight, conversion to GBP may be recommended. It is noteworthy that band erosion into the stomach, a not infrequent complication of the use of mesh in VBG or in the Angelchik prosthesis for gastroesophageal reflux treatment, has not been frequently reported. Longer follow-up is necessary to evaluate the true extent of this risk.
As after any form of gastroplasty, the patient may fail to lose weight or may regain lost weight. Inappropriate eating behaviors (e.g., intake of high-calorie sweets) are the most likely cause. If obesity-related comorbid conditions persist, conversion to proximal GBP is appropriate.
Outcome Evaluation
How successful LAGB is at achieving weight loss over the long term remains unclear. The adjustability and reversibility of the operation, as well as the decreased disability that results, make it attractive to both patients and physicians. The procedure appears to avoid some of the major postoperative complications associated with open GBP (e.g., incisional hernia, marginal ulcer, and stomal stenosis). Band slippage remains a major postoperative concern, however, though the incidence of slippage does appear to decrease as the surgeon’s experience with the procedure increases. More significant, there appears to be a high frequency of failed weight loss—as high as 15 to 20% of all patients undergoing the procedure and possibly even higher. European data confirm that there is a significant failure rate but also suggest that the remaining patients achieve a degree of weight loss approaching that seen with proximal GBP. Whether these reports will withstand the scrutiny of long-term follow-up remains to be seen.
Open Proximal Gastric Bypass
Proximal GBP results in greater weight loss than the gastric restrictive procedures (see above) and carries a lower incidence of weight regain; consequently, it is often considered the gold standard for bariatric surgery. Compared with the version of GBP performed at our institution, the original GBP created a much larger proximal gastric pouch and a much wider anastomotic opening, and it was often associated with inadequate weight loss. In the later version, three superimposed 55 or 90 mm staple lines are placed across the proximal stomach in such a way as to create a gastric pouch no larger than 30 ml with a Roux limb at least 45 cm long and a stoma no larger than 1 cm [see Figure 9]. This anatomic situation is largely replicated when GBP is done laparoscopically, but an isolated gastric pouch is created with stapled transection of the stomach.
Operative Technique
Step 1: Initial Incision and Abdominal Exploration
Once the patient is anesthetized, the abdomen receives a thorough, careful cleansing with povidone-iodine and is draped in a sterile fashion. An upper midline incision is made and extended through the fascia alongside the xiphoid process to facilitate cephalad exposure. The incision is routinely carried down to the supraumbilical area. The deep layer of subcutaneous fat can often be separated bluntly with aggressive lateral traction applied by the surgeon and the assistant, and the midline usually can then be identified for fascial incision. The electrocautery is used to enter the abdominal cavity, and a thick layer of subfascial preperitoneal fat is often encountered before entry into the peritoneal cavity. Abdominal exploration is undertaken in every patient, including examination of the liver for possible signs of liver disease. Other incidental findings may become apparent as well.
Troubleshooting
Unexpected significant liver disease is occasionally discovered at the time of operation. If the patient has cirrhosis without portal hypertension, one should perhaps proceed with bypass if the patient’s comorbid conditions make it mandatory; liver transplantation carries increased risk in morbidly obese patients. The gallbladder should be palpated for gallstones, which, if found, may be an indication for cholecystectomy at the time of the bypass procedure. If there are no visual or palpable gallbladder abnormalities, intraoperative ultrasonography may be used to examine the gallbladder.
It is not unusual to discover other previously unrecognized conditions during GBP, primarily because symptoms may not be obvious in morbidly obese patients and because their large size tends to make radiologic imaging difficult or even impossible. For example, intraoperative discovery of pelvic cysts and tumors is not uncommon in obese female patients. Such lesions may be excised during GBP; on occasion, if they appear benign and their location prevents safe excision, they may be managed with careful follow-up.
Step 2: Mobilization of Esophagus
The bypass procedure itself is begun by mobilizing the distal esophagus and encircling it with a soft rubber drain 0.5 in. in diameter. The gastrohepatic omentum is bluntly entered at a point overlying the caudate lobe, with care taken to look for and avoid injury to an aberrant left hepatic artery. The phrenoesophageal ligament overlying the anterior and lateral distal esophagus is sharply incised to facilitate subsequent blunt mobilization of the distal esophagus. To prevent esophageal injury, the nasogastric tube is carefully palpated within the lumen of the esophagus during mobilization, and blunt dissection proceeds widely around this important landmark. Laterally, dissection must be at the level of the esophagus or higher.
Troubleshooting
If dissection is too low laterally, it may result in blunt injury to the short gastric vessels, bleeding, and the need for urgent splenectomy, which is no easy task in a morbidly obese patient. In addition, it may lead to creation of an inappropriately large pouch by keeping the surgeon from recognizing that some of the stomach is above the level at which the encircling rubber drain is placed.
Step 3: Division of Mesentery and Dissection around Stomach
Once the esophagus is mobilized, the assistant’s left hand is placed through the gastrohepatic omental opening behind the stomach wall on the lesser curvature. The space between the first and second branches of the left gastric artery is then identified as a landmark for location of the gastric staple line, both to ensure that the pouch created is no larger than 30 ml and to prevent injury to the left gastric artery, which usually runs cephalad to this location. With the surgeon’s posterior finger pressing anteriorly to place tension on the tissue, a fine-tip right-angle clamp and the electrocautery pencil are used to divide the mesentery carefully at this level immediately alongside the stomach wall so as to create a mesenteric opening that will admit a large right-angle clamp.
The avascular tissue on the posterior wall of the stomach is then bluntly dissected between the opening in the gastrohepatic omentum and the lateral angle of His, which is identified by the encircling rubber drain. The blunt tip of a large 28 French red rubber tube is placed behind the stomach in a medial-to-lateral direction along this dissected path to encircle the stomach [see Figure 10]. The open end of the red rubber tube is subsequently brought through the previously created mesenteric opening with a large right-angle clamp. The stomach is now ready for stapling, and the red rubber tube serves as a guide for introduction of the stapler. At this point, all intraluminal tubes and devices (e.g., the nasogastric tube and the esophageal stethoscope) are removed from the esophagus by the anesthetist.
Troubleshooting
When a tube is inadvertently stapled within the stomach, excising it from the nontransected gastric staple line can be a technical challenge. To remove the stapled tube, it is generally necessary to use a stapler to transect the stomach, thereby creating the potential for significant injury to the gastric tissue unless the transection is precisely superimposed over the previous staple line. The tube can then be excised from each side (proximal and distal) of the divided gastric staple lines.
Step 4: Creation and Mobilization of Roux Limb and Jejunojejunostomy
The ligament of Treitz is identified, and the jejunum is measured to a point 45 cm beyond the ligament—or somewhat more distally to enhance mobilization of what will become the Roux limb if the mesentery appears foreshortened—at which point the jejunum is divided with a stapler. An 8 to 12 cm segment of jejunum may be resected at this point to create a larger mesenteric defect, which should facilitate mobilization of the limb to the proximal stomach. Mesenteric dissection is carried posteriorly in fat with the sequential application of clamps until further dissection appears either unnecessary for mobilization or unwise (i.e., likely to cause mesenteric vascular injury or ischemia of the Roux limb).
A side-to-side jejunojejunostomy is then created with a 60 mm linear stapler at least 45 cm beyond the initial point of jejunal division for standard proximal GBP. Some surgeons perform this anastomosis 150 cm downstream for the long-limb modification of the procedure used in superobese patients [see Operative Planning, Choice of Surgical Procedure, above] or even further distally for the distal GBP modification, which greatly enhances malabsorption. It is important not to narrow the efferent lumen at the jejunojejunostomy site, particularly with the longer-limb modifications, in which the lumen at the distal end of the Roux limb may be quite small. The enterotomies made to allow placement of the stapler can usually be closed with a 55 mm stapler loaded with 3.5 mm staples; however, if stapling would cause undue narrowing of the lumen, the closures should be handsewn instead.
Troubleshooting
It may be preferable to mobilize the Roux limb before committing to stapling the stomach so that it can be determined whether the limb can be extended to reach the proximal stomach without being placed under tension. In those rare cases in which the mesentery is too foreshortened to permit the limb to reach the proximal stomach, it is advisable to change the procedure to VBG or gastric banding rather than create a gastrojejunal anastomosis under tension and thereby incur the increased risk of leakage.
Step 5: Gastric Stapling and Gastrojejunostomy
The Roux limb is brought through the mesentery of the transverse colon with blunt dissection and then brought up to the proximal stomach. The 55 or 90 mm stapler, loaded with 4.8 mm staples, is guided behind the stomach by inserting its open-mouthed end into the lumen of the previously positioned red rubber tube. Once it is determined that the staple line will reach completely across the stomach and that the stomach is not folded on itself, the stomach is stapled three times in such a way that the three staple lines are superimposed [see Figure 11].
A 1 cm anastomosis is created between the proximal stomach pouch and the Roux limb. We prefer a handsewn anastomosis for this procedure, using an outer layer composed of interrupted 2-0 or 3-0 silk sutures and an inner layer composed of a continuous absorbable 3-0 polyglycolic acid (Dexon) suture. When the posterior aspect of the anastomosis is complete, a 30 French dilator is placed orally by the anesthetist and is guided through the anastomosis by the surgeon to ensure that the stoma has the appropriate diameter [see Figure 12]. The anterior aspect of the anastomosis is then completed.
Troubleshooting
A significant concern for many bariatric surgeons has been a high incidence of staple line disruption causing failed weight loss or weight regain; in one series, the incidence of such disruption was 35%. To minimize this risk, some surgeons advocate transecting the stomach. Currently, this step is routinely carried out as part of a laparoscopic GBP. In an open GBP, one may transect the stomach either by applying a linear cutting stapler with 3.5 or 4.8 mm staples (depending on the estimated gastric wall thickness) or by inserting two parallel noncutting transverse anastomosis (TA)–90 staplers and cutting between them with a scalpel after the staplers are fired. Other surgeons, however, prefer to leave the stomach undivided and oversew the staple line. In our version of open GBP, we find that placing three or four precisely superimposed staple lines reduces the incidence of staple line disruption to less than 2%.
Another advantage of gastric transection besides reduction of staple line disruption is that it allows the Roux limb to be brought up to the gastric pouch via a retrocolic and retrogastric tract, which is substantially shorter and places less tension on the limb. This approach is particularly helpful in severely obese patients with a fatty and foreshortened mesentery, in whom it is difficult to free the Roux limb sufficiently to reach the proximal stomach without tension. The possibility that gastric transection may prove helpful in a specific patient is another reason why it is advisable to delay stapling the stomach until the Roux limb has been mobilized.
Step 6: Assessment of Anastomosis
When the entire anastomosis is complete, the dilator is removed and an 18 French nasogastric tube is advanced by the anesthetist while the tip is carefully guided through the anastomosis by the surgeon. The Roux limb is occluded with the assistant’s left hand or with an atraumatic intestinal clamp, and the esophagus is occluded by placing tension on the rubber drain surrounding it while the anesthetist injects a series of 10 ml aliquots of methylene blue dye through the nasogastric tube to determine whether the anastomosis is leaking. A total of 30 to 60 ml of methylene blue must usually be injected; lesser amounts will not stress the suture line enough to constitute an adequate test. Alternatively, the anastomosis can be tested by performing intraoperative gastroscopy. If leakage is present, the air insufflated during the procedure will be visible bubbling from the leaking areas when the air-distended anastomosis is submerged in irrigation fluid.
Troubleshooting
When an intraoperative leak is identified, the area of leakage should be oversewn with silk sutures until injection of additional methylene blue dye via the nasogastric tube yields no further leakage. The most difficult area to repair is the posterior suture line, which is quite close to the gastric staple line. Posterior leaks are usually repaired by reinforcing the posterior suture line with additional sutures between the excluded stomach and the jejunal limb; often, the entire posterior suture line is oversewn. In addition, a viable pedicle of omentum may be mobilized and placed around the anastomosis for further reinforcement. Closed suction drains may also be placed in this area, both to detect possible postoperative leakage and to control a postoperative leak or fistula.
Finally, a gastrostomy tube may be placed in the excluded portion of the stomach. This measure provides postoperative decompression, which should prevent the development of undue tension on the Roux limb as a result of gastric distention. In addition, it establishes a route for enteral feeding if a fistula develops. Fortunately, such fistulas are rare. When they do occur, they often heal if (1) they are well drained, (2) there is no distal obstruction or local abscess, and (3) the patient is receiving nutritional support with no oral intake. A gastrostomy tube should also be placed in the distal gastric pouch when extensive adhesions from a previous procedure or a difficult gastric reoperation increase the risk of postoperative gastric distention.
Step 7: Closure
When the absence of leakage is confirmed or when any leaks identified have been controlled, the tip of the nasogastric tube may be positioned further down in the Roux limb and left to continuous suction overnight. All mesenteric defects—at the jejunojejunostomy, at the mesocolon, and behind the Roux limb (Peterson hernia)—are then closed to prevent an internal hernia. The abdominal fascia is reapproximated with a continuous double-looped No. 2 suture, subcutaneous tissues are irrigated with a crystalloid solution, and the skin is closed with skin staples. No subcutaneous sutures or drains are used in routine cases.
Complications
Proximal GBP is associated with a significant incidence of stomal stenosis and with marginal ulcer.55 The former responds to endoscopic stomal dilatation, and the latter usually responds to proton pump inhibitor (PPI) therapy. Addition of sucralfate to this regimen may be helpful. The risk of marginal ulcer appears to be increased in smokers and in patients who consume nonsteroidal anti-inflammatory drugs (NSAIDs). We routinely discourage NSAID use after GBP. Perforation of the proximal gastric pouch, probably arising from perforation of a deep ulcer, has been seen with administration of high-dose NSAIDs or with untreated ulcer diathesis.
Iron, vitamin B12, and folic acid deficiencies may occur but can usually be corrected with oral supplementation52; accordingly, GBP patients, like VBG and gastric banding patients, should be advised to take a multivitamin daily for life. Compared with gastroplasty and gastric banding, GBP results in significantly lower serum hemoglobin and iron concentrations. This is primarily a problem in menstruating women. All menstruating women who have undergone GBP should be treated prophylactically with supplemental oral ferrous sulfate, 325 mg/day. As many as six iron tablets a day may be required if menstrual bleeding is heavy. Hormonal therapy to control or temporarily eliminate menses may be helpful. On occasion, intramuscular iron injections or, rarely, hysterectomy may be necessary. The risk of vitamin B12 deficiency is higher after GBP than after gastroplasty or gastric banding, but this condition can be prevented with supplemental oral vitamin B12, 500 mg/day. A few patients may require (or prefer) monthly B12 injections, which they can learn to administer themselves.
Concerns have been expressed that GBP can lead to other divalent cation deficiencies. Our group has not encountered zinc deficiencies 5 to 9 years after GBP, though we have observed calcium deficiencies leading to osteoporosis, which may take many years to become manifest and may not be biochemically evident because of normal serum calcium levels. It is therefore recommended that all GBP patients take oral calcium supplements. Some may require vitamin D supplementation. Magnesium deficiencies should be treated with MgSO4 supplementation.
Although nutritional deficiencies do not appear to be a greater problem with long-limb GBP than with standard proximal GBP, monitoring patients for possible malabsorption of the fat-soluble vitamins A, D, and E after long-limb GBP is advisable.
BPD may be associated with all of the complications seen after GBP. In addition, patients who undergo BPD may experience diarrhea, severe protein malnutrition (manifested as hypoalbuminemia), and deficiencies of vitamins A (manifested as severe night blindness), D (manifested as severe osteoporosis), and E.50 Hypoalbuminemia may respond to oral pancreatic enzymes but often must be treated with total parenteral nutrition. In some patients, it may prove necessary to lengthen the absorptive intestinal tract from 50 cm to 200 cm.
Outcome Evaluation
A series of 672 open proximal GBP procedures reported a 1.2% incidence of anastomotic leakage with peritonitis, a 4.4% incidence of severe wound infections (defined as infections serious enough to delay hospital discharge), an 11.4% incidence of minor wound infections and seromas (which were easily treated at home), a less than 1% incidence of gastric staple line disruption with the use of three superimposed applications of a 90 mm linear stapler, a 15% incidence of stomal stenosis, a 13% incidence of marginal ulcer, a 16.9% incidence of incisional hernia, and a 10% incidence of cholecystitis necessitating cholecystectomy.47 Gallstones developed in 32% of the GBP patients who had a normal intraoperative gallbladder sonogram within 6 months of surgery, and sludge was observed in another 10%. In a multicenter randomized, prospective trial, the incidence of gallstones within 6 months of GBP was reduced from 32% to 2% by giving patients ursodeoxycholic acid, 300 mg twice daily.56 Gallstone formation beyond 6 months is uncommon. The operative mortality in this series was less than 1%. Patients with respiratory insufficiency of obesity had an operative mortality of 2.2%, whereas those without pulmonary dysfunction had an operative mortality of 0.4%.
Neither the data from this randomized, prospective trial nor the data from selective studies support the contention that VBG is safer than GBP. Although GBP includes one more anastomosis than VBG, complications such as leaks and peritonitis occur with both operations. A common criticism of GBP is that it is difficult to evaluate the distal gastric pouch and duodenum after the operation. Such evaluation, however, can be done in 75% of patients by means of retrograde passage of an endoscope into the duodenum and the stomach and in other patients by means of percutaneous distal distention gastrography. Bleeding from either the distal gastric pouch or a duodenal ulcer is rare. Gastric mucosal metaplasia of the bypassed portion of the stomach may occur in some 5% of patients after retrograde endoscopy, a finding that has raised concerns regarding the risk of carcinoma arising at that location. To date, however, although many thousands of these procedures have been performed over the past four decades, few cases of cancer in the bypassed stomach have been reported.
Laparoscopic Gastric Bypass
Laparoscopic GBP is currently the most popular bariatric procedure in the United States, both because of the rapid weight loss it achieves and because of the strong overall surgical trend toward minimally invasive approaches. As noted [see Operative Planning, Laparoscopic versus Open Approach to Bariatric Surgery, above], laparoscopic GBP achieves the same weight-loss results as open GBP but yields less pain, reduced disability, and a shorter duration of hospitalization. Physiologically, laparoscopic GBP results in less operative trauma than open GBP, less impairment of pulmonary function, and a less pronounced stress response. In addition, the laparoscopic technique is associated with lower incidences of major wound infections and incisional hernias. Accordingly, we recommend laparoscopic GBP over any other bariatric procedure.
Laparoscopic GBP poses significant technical challenges, even for surgeons with advanced laparoscopic skills. Most of the variations seen at different institutions are related to various techniques for creation of the gastrojejunal anastomosis, with some groups using a circular stapler, others a linear stapler, and still others a handsewn technique. The anvil of the circular stapler may be placed within the proximal gastric pouch either by means of flexible upper GI endoscopy, through an approach similar to the snare-and-wire technique used for placement of a percutaneous endoscopic gastrostomy (PEG) tube [see 5:18 Gastrointestinal Endoscopy], or by means of a gastrotomy of the stomach before pouch creation for intra-abdominal anvil placement, followed by staple closure of the gastrotomy. Peroral placement of the stapler’s anvil can be problematic: even the small 21 mm anvil is hard to pass through the proximal esophagus in some patients. To facilitate esophageal passage, a ‘flip-top’ anvil design has been introduced. With this design, a 25 mm anvil can generally be passed without undue difficulty, thereby lowering the risk of postoperative stenosis. We routinely use the linear stapling method to create the gastrojejunal anastomosis; it is easier than circular stapling in this setting, and there is no risk of esophageal trauma from anvil passage.
Operative Technique
Step 1: Initial Access and Trocar Placement
Initial access to the abdomen is obtained through a small left subcostal incision. Gas is insufflated into the abdomen via a Veress needle to a pressure of 15 mm Hg; on occasion, a pressure of 18 to 20 mm Hg may be necessary. A dilating 5 mm trocar is then placed in this location. Many surgeons use commercially available trocars that allow direct vision through the scope during passage of a 12 mm trocar. We encourage preinsufflation of the abdominal cavity before such a device is employed so as to enhance identification of the peritoneal sac and avoid organ injury. Additional trocars are placed in specific locations [see Figure 13]. The liver is retracted with a metal Nathanson liver retraction device anchored to the bed, which is inserted after a 5 mm sharp trocar is used to develop a tract into the abdominal cavity in the subxiphoid position and removed. If the left lateral section of the liver is very large (as in patients with steatosis), additional liver retractors may be necessary.
On occasion, the enlarged fatty falciform ligament must be dissected from the anterior abdominal wall with an ultrasonic scalpel or a bipolar cautery device. The advent of long laparoscopic graspers, staplers, and energy dissectors has facilitated operating on the proximal stomach and allows the use of trocar locations away from the abdominal midline. A 12 mm port placed in the right paramedian position serves as the surgeon’s primary operative port; two lateral subcostal 5 mm ports allow both surgeon and assistant to employ two-handed techniques for the entire procedure. In most patients, a 45° angled viewing 5 mm laparoscope is inserted via a supraumbilical 5 mm trocar. A longer 10 mm scope may enhance visibility, particularly for especially heavy or tall patients, in whom a 5 mm scope may be subject to damage from excessive torque. High-definition imaging improves visualization during the procedure.
Step 2: Creation of Roux Limb and Jejunojejunostomy
In most reports of laparoscopic GBP, regardless of how the gastrojejunostomy is done, the approach to creating the Roux limb is essentially the same. The patient is placed in a supine position, and graspers are used to bring the omentum upward into the upper abdomen so that the transverse colon and the underlying mesocolon are exposed. Graspers are then placed on the transverse mesocolon and used to elevate it anteriorly so that the ligament of Treitz is exposed. The position of the ligament of Treitz is confirmed by careful manipulation and verification that the bowel is attached to the retroperitoneum at this location; this may be a more difficult task in patients who have previously undergone abdominal procedures.
With the help of a measuring instrument, the small bowel is measured to a point 50 cm from the ligament of Treitz, where it is transected with the endoscopic gastrointestinal anastomosis (GIA) stapler, loaded with 2.5 mm staples. A 0.5 in. Penrose rubber drain may be sutured to the cut end of the Roux limb so that it is not confused with the other cut end of the bowel. The Roux limb is then measured to a length of 45 to 60 cm. (As in open GBP, the Roux limb should be significantly longer—up to 150 cm—if the long-limb modification is being performed.) The afferent side of the previously transected small bowel is then attached with a simple absorbable suture to the proposed jejunojejunostomy site on the Roux limb. Intracorporeal suturing is facilitated by using an automatic suturing device. Positioning is important: the afferent limb should be kept toward the mesocolon (toward the left side of the surgeon’s field of view), with the Roux limb brought toward the surgeon (visualized on the right side of the operative field of view).
Two holding sutures are placed, one proximal to the proposed site of the enterotomy for the anastomosis and the other distal to this site, to help manipulate the bowel onto the stapler. A small (1 cm) enterotomy is made with the electrocautery in each of the two adjacent bowel limbs in preparation for passage of the linear stapler, loaded with 2.5 mm staples in a 60 mm cartridge, into the bowel. The stapler is then fired, creating a 60 mm side-to-side anastomosis. A suture is placed at the staple line to elevate the corner of the anastomosis for subsequent stapled closure of the defect, and a third holding suture is placed at the midpoint of the enterotomy. The three sutures are grasped to facilitate closure of the enterotomy by another application of the linear stapler, with great care taken to avoid narrowing at the junction of the Roux limb and the large common channel of the anastomosis. To facilitate closure without obstruction, all three knots should be visible above the stapler, but tissue amputation should be minimal. Once completed, the anastomosis is inspected both for integrity and for possible narrowing. At this point, cephalad traction is applied to the remaining suture (in the medial position) to facilitate placement of a continuous suture to close the mesenteric defect.
Some surgeons prefer to create a loop gastrojejunostomy, thereby avoiding the technical challenges associated with creating a Roux limb laparoscopically. This approach was abandoned years ago in open GBP because of the unacceptably high incidence of postoperative bile reflux and the increased severity of complications resulting from high output of digestive juices when leakage occurred at the gastrojejunal anastomosis; it should be abandoned in laparoscopic GBP as well. The practice of using such suboptimal methods for the purpose of performing this complex operation more expeditiously is poorly conceived.
Step 3: Passage of Roux Limb
Next, the greater omentum is divided from its free edge to its junction with the transverse colon so that the limb can be brought up in an antecolic fashion between the divided halves of the omental ‘apron,’ which reduces tension on the limb. Alternatively, a retrocolic, retrogastric tunnel may be created so that the Roux limb can be advanced to the proximal stomach for anastomosis. The retrocolic, retrogastric approach is superior if the antecolic approach appears to be placing undue tension on the limb as it is advanced to the proximal pouch. For retrocolic passage, the ligament of Treitz is identified by lifting the transverse mesocolon anteriorly, and a spot 1 to 2 cm anterior and to the left of the ligament is chosen as the starting point for electrocautery dissection. The middle colic artery should be medial to this point of entry into the mesocolon. The goal of the dissection is to identify the posterior wall of the stomach, which may be difficult in patients who are extremely obese, have a fatty, foreshortened mesocolon, or have previously undergone abdominal surgery.
Once the stomach is visible, it is grasped and elevated through the mesocolic window, and the end of the Penrose drain is grasped and brought through the mesocolic defect into the lesser sac. When the Penrose is in place in the lesser sac, the omentum is pulled down from the epigastrium to allow visualization of the stomach, and the patient is placed into a steep reverse Trendelenburg position. The Penrose drain will be exposed when the cutting stapler is employed to create the proximal gastric pouch, and care must be taken to avoid stapling the drain.
There has been some controversy regarding the relative merits and deficiencies of antecolic and retrocolic techniques for passage of the Roux limb. The original open GBP often made use of a retrocolic, antegastric approach. The subsequent evolution of gastric transection methods led to a retrocolic, retrogastric approach to limb passage, which decreased the distance the limb had to travel to reach the proximal stomach and reduced the tension placed on the gastrojejunal anastomosis. Eventually, the antecolic, antegastric technique was introduced; this approach became popular with laparoscopic surgeons because it usually made the procedure faster to perform. The advantages of this technique were confirmed by a study that prospectively compared 33 consecutive patients who underwent retrocolic LRYGB with 33 who underwent antecolic LRYGB over a 3-year follow-up period.57 The results suggested a similar decrease in BMI (from 45 kg/m2 before operation to 34 kg/m2 at 36 months) and a similar incidence of complications (e.g., internal hernias and strictures). Operating time was significantly shorter for the antecolic procedure (mean, 188 minutes) than for the retrocolic procedure (mean, 219 minutes).
Other issues that have been raised in comparing the two techniques include the risk of internal hernias through mesenteric defects and the various risks inherent in an anastomosis performed under tension (e.g., leakage, ischemic stricture, and ulceration). In addition, retrocolic passage of the Roux limb during LRYGB leaves a short segment of the limb that is not easily visualized; unrecognized twisting of this segment may occur and lead to postoperative obstruction. A 2007 study that evaluated 754 LRYGB patients (300 retrocolic, 454 antecolic) over a median follow-up period of 16 months found that the rate of complications (e.g., surgical exploration for intestinal obstruction and internal hernias) was higher after the retrocolic procedure.58 Another 2007 study that evaluated 353 LRYGB patients (218 retrocolic, 135 antecolic) over a mean follow-up period of 28 weeks found that the incidence of postoperative gastrojejunal leakage was higher after the antecolic procedure.59 These varying study outcomes suggest that a prospective, randomized trial will ultimately be required to determine whether antecolic Roux limb passage is superior or inferior to retrocolic passage with respect to outcomes or complication rates.
Both techniques continue to be employed today, and the current evidence is not sufficient to support a blanket recommendation favoring one over the other. We would maintain, however, that if undue tension is evident when the Roux limb is passed via the antecolic pathway, it is advisable to switch to the shorter route available via the retrocolic, retrogastric pathway.
Step 4: Dissection around Stomach and Creation of Gastric Pouch
The mesentery of the lesser curvature is transected with a bipolar electrocautery device to provide hemostasis. Despite the potential for problems with transection of the neurovascular bundle, no clear evidence of such problems has been found in hundreds of procedures performed with this access technique. Dissection posterior to the stomach is performed in the avascular free plane of the lesser sac. Additional dissection along the lesser curvature is not recommended, because it may increase the devascularization of the pouch. Further dissection is done at the angle of His to create a connection with the posterior gastric space. A linear endoscopic GIA stapler loaded with 3.5 mm staples in 60 mm cartridges is then employed in sequential firings to transect the stomach and create the proximal gastric pouch; three or four firings are usually necessary [see Figure 14]. When revisional bariatric surgery is performed on the previously operated-on stomach or when buttressing materials are used to reinforce the staple line, a staple height of 4.8 mm is usually required.
Step 5 (Circular Stapling): Placement of Stapler in Gastric Pouch
As noted (see above), surgeons use several different techniques to complete the gastrojejunal anastomosis. If a linear stapler is used, the next step is gastrojejunostomy [see Step 6b (Linear Stapling), below]. With the technique reported in Wittgrove’s original description of the procedure,60 however, in which the anvil of a circular stapler is passed down the patient’s esophagus, the next step in the procedure is to have an assistant perform flexible upper GI endoscopy of the gastric pouch. The pouch wall is transilluminated by the endoscope light, and a site is chosen for the gastrojejunostomy. The endoscopist then places an endoscopic snare, which can be seen pressing against the tissue of the pouch wall. A small opening is made in the pouch with the electrocautery scissors so that the snare can be pushed through the gastric wall at this location. The snare is then used to grasp a wire placed through a needle across the abdominal wall in the left abdomen, and snare and wire are withdrawn through the mouth along with the scope.
The anvil of the stapler is attached to the end of the wire that was drawn through the mouth, and the surgeon pulls on the other end of the wire to deliver the anvil through the mouth, down the esophagus, and into the gastric pouch, where it can be visualized. The electrocautery is used to enlarge the opening in the gastric wall slightly, and the stem of the stapler is then brought through the gastrotomy. To prevent anastomotic leakage after stapling, the gastrotomy should be no larger than the diameter of the stem; if it is too large, it can be closed around the stem by placing one or two simple sutures.
An alternative technique for anvil placement in the pouch involves making a gastrotomy distal to the planned staple line before transection of the stomach. After the anvil is introduced into the abdomen via a dilated trocar site, a long sharpened dissector is employed to grasp a suture tied to the anvil stem. The dissector is then passed into the lumen of the stomach and used to perforate the future pouch in location that is appropriate for the eventual anastomosis. Once the anvil stem has been advanced through the perforation, the dissector is withdrawn. Stapling of the stomach may include amputation of the gastrotomy site. The pouch is created by stapling around the anvil and thus can be made very small.
Troubleshooting
Difficulty in passing the anvil perorally may arise at the level where the trachea separates from the esophagus in the deep pharynx. This difficulty can usually be overcome either by having the endoscopist perform a jaw-thrust maneuver or by placing a large laryngoscope blade deep in the pharynx to make the anvil visible in the proximal esophagus and then nudging the anvil forward with either the tip of the blade or a McGill forceps. Transiently deflating the endotracheal tube balloon may also help. Occasionally, a large, blunt esophageal dilator is used to place pressure on the top of the anvil. Given the potential for esophageal injury if the anvil will not advance, it is important not to apply excessive force. In one case from our experience, the anvil became lodged in the proximal esophagus beyond the laryngoscopic view, and the long suture holding it broke; retrograde passage of an esophageal dilator placed via a gastrotomy in the pouch was required to dislodge the anvil. Other surgeons who use wire to draw the anvil down the esophagus have identified nontransmural esophageal injuries on postoperative contrast studies or have seen subcutaneous emphysema in the neck after operation. There is at least one case report describing an esophageal perforation with this technique.
Step 6a (Circular Stapling): Gastrojejunostomy
In the circular stapling technique, the stapled end of the Roux limb is opened to permit introduction of the stapler. A 12 mm trocar site in the left upper quadrant is dilated so that the circular stapler can be inserted through the abdominal wall without the need for a trocar. Lubrication is helpful for this step, and covering the device with a sterile plastic bag helps to protect the wound from contamination when the device is extracted. The transabdominal stapler then cannulates the Roux limb. The stapler is advanced 3 to 4 cm down the limb, and the spike on the body of the device is brought through the antimesenteric portion of the bowel by unscrewing the stapler under direct vision. Once the stapler has been opened completely, it is laparoscopically joined to the anvil protruding from the gastric pouch, then closed and fired.
Once fired, the stapler is removed from the abdominal wall, and a balloon trocar device is used to close the dilated abdominal wall opening. A single firing of the endoscopic GIA stapler, loaded with 2.5 mm staples, is often all that is required to close the enterotomy left from passage of the stapler. Interrupted or continuous absorbable sutures are then placed around the stapled anastomosis to provide added security and reduce tension on the staple line.
Step 6b (Linear Stapling): Gastrojejunostomy
Initially, a continuous posterior row of nonabsorbable suture material is placed to secure the Roux limb to the posterior gastric pouch. An enterotomy and a gastrotomy are performed that are large enough to admit the jaws of the endoscopic GIA stapler, which is loaded with 3.5 mm staples in a 45 mm cartridge for a side-to-side anastomosis [see Figure 15] by means of the same techniques employed in creating the jejunojejunostomy. The cartridge is inserted to its full length and fired to create an inner stapled layer [see Figure 16]. We use the full length of the staple cartridge because we have found that our technique (a complete two-layer anastomosis that includes 360° oversewing of the anastomosis over a 30 French dilator or a flexible 9 to 11 mm gastroscope) can lead to obstruction if the full cartridge length is not employed. The remaining gastroenterotomy defect is closed in two layers with continuous sutures (absorbable for the inner layer, nonabsorbable for the outer).
In our experience, using the linear stapler for the gastrojejunostomy simplifies the procedure, reduces operating time, and eliminates the concerns about injury to the body of the esophagus that arise with passage of the circular stapler.
Step 6c (Handsewn Anastomosis): Gastrojejunostomy
Some surgeons employ laparoscopic suturing techniques to create a handsewn gastrojejunostomy, usually with a single layer of continuous nonabsorbable suture material. In particular, robotic surgery techniques usually include hand suturing, using the robotic effectors to grasp the tissue and the needle and, ultimately, to tie the suture. Robotic techniques are hampered by the setup time required for placement of the robotic arms, but they have been touted as being particularly useful for operating on superobese persons, in whom manipulation of traditional laparoscopic instruments is made difficult by the extreme thickness of the abdominal wall, which interferes with the trocar’s fulcrum effect. In such cases, use of a robotic technique appears to improve the ergonomics of the procedure and relieve the surgeon’s hand and arm fatigue.
Step 7: Assessment of Anastomosis
In every case, regardless of which anastomotic technique is employed, flexible upper GI endoscopy is performed to assess the anastomosis. The Roux limb is occluded with an intestinal clamp to prevent excessive bowel and distal gastric dilatation. The patient is placed in the supine position, and the area around the anastomosis is irrigated with saline; the presence of air bubbles, easily detectable in the irrigant, indicates that the anastomosis is leaking. In most cases, the pouch and the Roux limb can be distended tightly, and even tiny air leaks are reinforced with additional sutures. The anastomosis and the staple lines are visualized, and the endoscope is navigated through the anastomosis into the Roux limb whenever possible. After adequate visualization and testing, the gas is suctioned from the intestine, the Roux limb is unclamped, and the endoscope is removed. Alternatively, some surgeons prefer to distend the anastomosis with methylene blue dye to exclude leakage.
Step 8: Closure
Finally, a 10 mm closed suction drainage tube may be placed adjacent to the anastomosis to permit monitoring for postoperative leaks. In our program, we no longer do this on a routine basis. If a drain is placed, it is usually removed after the patient begins oral intake. Selected patients undergo upper GI series to evaluate for postoperative leakage [see Figure 17]. This radiographic study is considered mandatory in patients with equivocal postoperative signs and symptoms of leakage, though surgical reexploration may be preferable and is a more definitive assessment in such patients.
In antecolic Roux-en-Y procedures involving division of the greater omentum, the lateral tongue of greater omentum may be wrapped in a lateral-to-medial direction posteriorly around the gastrojejunostomy, then sutured to the anterior pouch tissue so as to reinforce the anastomosis. We do not do this routinely—only when we have technical concerns about the integrity of the anastomosis. We also sometimes use the distal gastric remnant as a live tissue patch over areas of concern in a difficult anastomosis. The liver retractor is removed under direct vision to ensure that no bleeding occurs. When dilating trocars have been employed, the trocar sites are not routinely closed. Trocar sites manually dilated to permit extraction of a specimen (e.g., gallbladder) or passage of a circular stapler should be closed with sutures to avoid risk of hernia formation; we have found that such closure increases postoperative incisional pain at these sites. Skin wounds are closed with minimal subcuticular sutures, and the epidermis is reapproximated with commercially available skin closure adhesives.
Hand-Assisted Laparoscopic Gastric Bypass
Because total intracorporeal laparoscopic GBP is such a challenging technical adventure, a hand-assisted version of the procedure was developed.61 This technique served as a bridge to the total intracorporeal approach, in that it made it possible to learn the technical aspects of a difficult, highly advanced laparoscopic procedure while enjoying the security provided by the presence of a hand within the abdomen for palpation and manipulation during the procedure. This added security is the major advantage of the hand-assisted approach. The major disadvantage is the potential for complications at the incision used for manual access. The complications seen at this site are reminiscent of those seen after open GBP, including major wound infection, dehiscence, and hernia formation.
In a series of hand-assisted laparoscopic GBP procedures from our institution, there was one major wound infection in the hand incision and one instance of postoperative fascial dehiscence. Subsequent study suggested that the hand-assisted procedure did not reduce the incidence of wound-related complications and incisional hernias and that it significantly increased the cost of surgical treatment when compared with open GBP. It appears, therefore, that the primary role of hand-assisted laparoscopic GBP may be in helping surgeons to negotiate the steep learning curve associated with total laparoscopic GBP. Some surgeons, however, have persisted with hand-assisted techniques, and large series have been published.
Complications
The complications observed to date after laparoscopic GBP include the usual problems that occur in some patients after open GBP, including marginal ulcer and stenosis at the gastrojejunal anastomosis necessitating dilatation. On rare occasions, a gastrogastric fistula may lead to a treatment-resistant marginal ulcer. The major advantage of laparoscopic GBP over open GBP is likely to be reduced wound complications (e.g., major wound infection and incisional hernia). We have seen several relatively minor trocar site infections after laparoscopic GBP but none that carried the long wound-care disability characteristic of a major wound infection after open GBP. Intermediate-term weight loss with laparoscopic GBP appears to be identical to that with open GBP.
Postoperative Management
After operation, the obese patient should be kept in the reverse Trendelenburg position and should not be extubated until he or she is fully alert and showing evidence of adequate ventilatory effort [see 8:6 Mechanical Ventilation]. In the absence of respiratory insufficiency, most obese patients can be extubated in the OR or the recovery room and returned to a standard hospital room.
Patients with obstructive SAS may have to be managed with overnight mechanical ventilation in the ICU, particularly if an open bariatric procedure was performed. Patients who were receiving ventilatory support with nasal CPAP before operation should have this treatment reinstituted after operation; monitoring for prolonged apnea should be continued in the ICU or in a stepdown unit with digital oximetry. If apnea occurs, simply waking the patient should correct the problem.
Patients with OHS may require prolonged mechanical ventilation until the pain of breathing resolves, particularly after open procedures. Such patients cannot be expected to manifest normal ABG values, and they should be weaned to their preoperative values—hence the value of obtaining. baseline ABG values before operation in these patients. The weaning process may require several days. It is important that these patients remain in the reverse Trendelenburg position to maximize diaphragmatic excursion by reducing the pressure on the chest cavity that may result from the often very large and heavy abdominal cavity. Swan-Ganz catheters, inserted preoperatively in patients with severe OHS, are useful in monitoring postoperative intravascular volume and oxygen delivery status. Excessive diuresis or restriction of fluids should be avoided.
It is extremely important to encourage early postoperative ambulation for the morbidly obese patient. These patients often experience less pain than one might expect, and it is frequently possible to get motivated patients up and walking in the afternoon or early evening after a major abdominal procedure. If the patients have been advised preoperatively of the merits of early postoperative ambulation and know it is for their own welfare, they may be more willing to cooperate.
These basic principles of postoperative management generally apply to laparoscopic cases as well, but with some differences. Unlike patients who have undergone open GBP, those who have undergone laparoscopic GBP usually do not have a nasogastric tube left in place. The bariatric surgical patient may begin to drink small amounts of liquids on postoperative day 1 and may be kept on a liquid diet with liquid protein supplementation for several weeks. Alternatively, many programs advance postoperative patients to a pureed diet with no sugar or concentrated sweets as soon as they can tolerate it. We have found that when patients consume only liquids during the edematous healing phase of the anastomosis, there is less need for urgent dietary counseling during the first few weeks after surgery. Discharge usually takes place between 1 and 3 days after operation. Vitamin administration should be initiated early after operation; chewable tablets may be used if necessary. Thiamine deficiency is very uncommon but can be quite serious if it progresses to the Wernicke-Korsakoff syndrome of neurologic damage. Such deficiency may develop within weeks in patients who are kept on a liquid-only diet without multivitamins but appears to be more common in patients who experience persistent vomiting. Any postoperative bariatric surgical patient with unexplained neurologic symptoms (e.g., visual changes, confusion, sensory changes in the extremities, or gait disturbance) should be considered for evaluation of potential nutritional causes, including thiamine deficiency and vitamin B12 deficiency.
The basic principles of postoperative management apply to both laparoscopic and open cases.
General Complications of Surgery in the Morbidly Obese Patient
The following are some of the main complications that may be associated with any abdominal operation (open or laparoscopic GBP, VBG, or LAGB) in a severely obese patient.
Abdominal Catastrophe
It may be very difficult to recognize an abdominal catastrophe in patients who are very young, very old, or morbidly obese or who are receiving high doses of steroids. For example, the obese patient may present in the ED with a perforated duodenal ulcer or a ruptured diverticulum, complaining of abdominal pain, and yet on abdominal examination have no evidence of peritoneal irritation (i.e., no guarding, tenderness, or rigidity). This situation has been well documented in patients in whom an anastomotic or gastric leak has developed after operation for morbid obesity.62 Symptoms include shoulder pain, pelvic or scrotal pain, back pain, tenesmus, urinary frequency, and, of great importance, marked anxiety. Signs of infection (e.g., fever, tachypnea, and tachycardia) may be absent, though tachycardia is often the first sign of a significant problem. Patients with peritonitis often have clinical symptoms and signs suggesting a massive pulmonary embolus: severe tachypnea, tachycardia, and sudden hypotension. Such acute pulmonary failure is probably secondary to sepsis-induced acute respiratory distress syndrome (ARDS). Thus, peritonitis must be suspected in any morbidly obese patient with acute respiratory failure. One advantage of the laparoscopic approach to bariatric surgery is that if there is concern about a possible leak, reexploration can be carried out without the need to reopen a large abdominal incision.
Because a high index of suspicion of peritonitis is required to detect the condition in morbidly obese patients, radiographic contrast studies with water-soluble agents such as diatrizoate meglumine may be indicated even when there are few clinical signs. If a perforated viscus is suspected, exploratory laparoscopy or laparotomy may be necessary despite normal findings on radiographic contrast study.
Internal Hernia
GBP places patients at risk for internal hernia with a closed-loop obstruction, leading to bowel strangulation. There are three typical locations for these internal hernias: the jejunojejunostomy anastomosis, the opening in the transverse mesocolon through which the retrocolic Roux limb is brought, and the Petersen hernia (located posterior to the Roux limb between the Roux mesentery and the transverse mesocolon). The primary symptom of an internal hernia is periumbilical pain, usually in the form of cramping consistent with visceral colic. These internal hernias may be very difficult to diagnose. Upper GI radiographic series and abdominal CT scans are often normal, providing a false sense of security. The resulting assumption that no problem exists may be devastating for the patient should bowel infarction occur as a consequence of closed-loop obstruction. The plain abdominal radiograph should always be carefully inspected for abnormal placement or spreading of the staples in the Roux-en-Y anastomosis. The safest course of action in patients with recurrent attacks of cramping periumbilical pain is abdominal surgical exploration. The frequency of this complication seems to have increased with the advent of laparoscopic GBP, presumably because of the difficulty of closing the potential hernia spaces completely. Some attribute the problem to the decreased tendency toward adhesion formation after laparoscopic surgery or to reduction of the intra-abdominal fatty tissue in the mesentery after successful weight loss surgery. We have seen one patient who had a patent mesenteric defect despite an intact suture; the apparent cause of the defect was a dramatic reduction in the mesenteric fat incorporated in the closure.
Acute Gastric Distention
After GBP, massive gaseous distention occasionally develops in the distal bypassed stomach, sometimes leading to a gastric perforation or disruption of the gastrojejunostomy. The primary symptoms of this complication are hiccups and a bloated sensation reported by the patient. Massive gastric dilatation can lead to severe left shoulder pain and shock. During the era when open GBP was predominant, gastric paralytic ileus was a known cause of this complication, particularly in patients requiring extensive adhesiolysis at the time of the bypass. Currently, with the advent of laparoscopic GBP, the problem is usually secondary to transient edema or to mechanical obstruction at the jejunojejunostomy anastomosis. The diagnosis is made by means of an urgent upright abdominal radiograph, which reveals the markedly dilated and air-filled bypassed stomach. Occasionally, the stomach is filled with fluid, and the diagnosis may be more difficult; in such cases, CT scanning may be helpful. Percutaneous transabdominal skinny-needle decompression can aid in the management of this complication and allow time for tissue edema at the jejunojejunostomy to resolve. If the dilatation recurs or the patient experiences serious difficulty, an emergency laparotomy should be performed, a gastrostomy tube inserted, and the jejunojejunostomy evaluated.
Altered Insulin Requirements in Diabetic Patients
Patients with type 2 diabetes may require large amounts of insulin for blood glucose control because of significant insulin resistance. It is not unusual, however, to note a complete absence of the requirement for insulin in the immediate postoperative period in morbidly obese patients. Therefore, insulin should be withheld on the morning of operation. In morbidly obese patients who have undergone GBP, there is often a marked reduction in the requirement for insulin throughout the postoperative period and even at discharge, possibly because of increased release of gastric inhibitory peptide (GIP) from the proximal small bowel. Therefore, regular subcutaneous insulin should be administered to GBP patients according to a sliding scale after operation until insulin requirements can be determined. Before discharge, the patient should be taking an appropriate dose of insulin, but afterward, he or she must perform frequent finger-stick blood glucose determinations, given that the need for insulin will decrease progressively with weight loss.
In one study of 23 patients with diabetes mellitus who underwent gastric bariatric operation, the average requirement for insulin decreased from 74 units/day before operation to 8 units/day after operation.63 Fourteen of the 23 patients were able to discontinue insulin completely, 11 by the time of discharge from the hospital 1 week after operation. These benefits were maintained during long-term follow-up to 39 months and were a result of a major decrease in insulin resistance that was associated with decreased food intake, as well as with weight loss.
Failed Weight Loss and Weight Regain
A postoperative problem that deserves special mention is the risk of failed weight loss or weight regain. This is one of the most difficult problems associated with bariatric surgery and may arise after any gastric procedure for morbid obesity. Patients who have undergone gastroplasty or gastric banding may have difficulty with solid foods and come to exhibit maladaptive eating behavior involving frequent ingestion of high-calorie liquid carbohydrates (a common reason for failure of a bariatric procedure). Conversion to GBP appears to be a successful management strategy for these patients. In a study in which 53 VBG patients were converted to GBP, the average loss of excess weight after VBG was 31 P5%; 2 years after conversion to GBP, the average loss of excess weight increased to 67 P2%, a value virtually identical to that in the primary GBP group.64
Inadequate weight loss is also seen in GBP patients. In some, stomal dilatation eventually develops after the procedure; however, no correlation between stomal size and weight loss has been demonstrated for GBP patients, and reoperation to make the pouch or the stoma smaller has not yielded any benefit over time when the initial procedure has failed. New techniques for narrowing the dilated gastrojejunostomy stoma endoscopically are currently being tested, but there remains the larger question as to whether such interventions are of any real value for long-term weight control. In a small percentage of patients, the failure of GBP may be attributable to either the loss or the absence of dumping syndrome symptoms, which leads to resumed ingestion of high-calorie sweets or, more commonly, to frequent ingestion of high-fat junk foods (e.g., potato or corn chips, microwave popcorn, and peanut butter crackers) that crumble easily and empty quickly from the pouch, thereby keeping the patient from feeling full. Repeated dietary counseling over a period of years is required to educate patients to eat low-calorie, high-fiber foods (e.g., raw carrots, broccoli, cauliflower, apples, and oranges) that stay in the small gastric pouch longer and provide a sensation of early satiety.
We make clear to patients, well in advance of the operation, that bariatric surgery is designed to provide them with a tool that will assist them in behavior modification and thereby help them help themselves. Obesity can be beaten by surgical treatment, but patients must continue to make good food choices. Patients who begin to ingest more than 1,100 kcal/day often begin to gain weight; even if the weight gain is only 0.5 lb/month, this amounts to 6 lb/year, or 60 lb in 10 years. Bariatric surgical patients may need lifelong nutritional counseling to optimize the results of surgical management of morbid obesity. In addition, appropriate regular physical exercise is an important adjunct to surgical treatment, and patients who comply with exercise treatment not only lose more weight but also are better able to maintain their weight loss. Accordingly, we recommend that patients follow a suitable exercise regimen for the rest of their lives
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