Acs0507 Surgical Treatment Of Morbid Obesity 2008


Published on

1 Like
  • Be the first to comment

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Acs0507 Surgical Treatment Of Morbid Obesity 2008

  1. 1. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 5 GI TRACT AND ABDOMEN 7 SURGICAL TREATMENT OF MORBID OBESITY — 1 7 SURGICAL TREATMENT OF MORBID OBESITY Eric J. DeMaria, MD, FACS, and Christopher J. Myers, MD It is clear that severe obesity is associated with a significant anastomotic leakage). The ensuing discussion begins by increase in morbidity1 and a decreased life expectancy.2 focusing on issues that the surgeon should carefully consider Morbid obesity—defined as (a) a body weight that exceeds when operating on an extremely overweight patient. 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.3,4 To date, attempts to manage Much has been written about the increased health risks morbid obesity with medical weight reduction programs have inherent in central (android) fat deposition as compared with met with an unacceptably high incidence of recidivism.5 The peripheral (gynoid) fat deposition. It is thought that in the approach that has had the greatest and longest-lasting success former, the increased metabolic activity of mesenteric fat is associated with increased metabolism of amino acids to in achieving weight loss is bariatric surgery. sugar, which leads to hyperglycemia and hyperinsulinism. Hyperinsulinism gives rise to increased sodium absorption Preoperative Evaluation and hypertension. Furthermore, central obesity has been linked to hypercholesterolemia. Hence, these patients have Many surgeons are afraid to operate on the morbidly a significantly higher incidence of diabetes, hypertension, obese patient because they presuppose a marked increase in hypercholesterolemia, and gallstones8—which explains the perioperative morbidity and mortality. It is now possible, higher mortality of the apple distribution of body fat in com- however, to stratify the mortality risk for patients undergoing parison with the pear distribution. In the past, fat distribution gastric bypass (GBP) by using a scoring system known as the was measured on the basis of the waist-to-hip ratio; however, Obesity Surgery Mortality Risk Score (OS-MRS), which computed tomographic scanning has shown that abdominal includes five independent variables that can be identified pre- circumference is a more accurate measurement of central fat operatively: (1) BMI greater than or equal to 50 kg/m2, (2) distribution.9 Morbidly obese women have significantly male gender, (3) hypertension, (4) pulmonary embolus risk increased intra-abdominal pressure (IAP), and this increase (including previous thrombosis, pulmonary embolus, inferior is associated with stress and urge overflow urinary inconti- vena cava [IVC] filter, right-side heart failure, and obesity nence.10 With weight loss comes a significant decrease in hypoventilation syndrome [OHS]), and (5) patient age greater bladder pressure and correction of incontinence. IAP, as than or equal to 45 years. These factors were associated with reflected in bladder pressure, appears to be closely correlated a greater 90-day mortality in a prospective study of 2,075 with sagittal abdominal diameter and waist circumference but patients who underwent GBP at a single institution,6 which not with waist-to-hip ratio (many morbidly obese patients was the basis for the initial proposal of this scoring system. have both central and peripheral obesity). The increased IAP The OS-MRS was subsequently validated in a multicenter associated with central obesity may give rise to other comorbid study involving four institutions and 4,431 patients.7 With the factors as well, including venous stasis ulcers, OHS [see Respiratory Insufficiency of Obesity, below], gastroesophageal presence of each variable equal to 1 point, each patient’s reflux, and inguinal and incisional hernias. 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 Obese patients are at risk for respiratory difficulties, which B; mortality, 1.1%); and those with a score of 4 or 5 had a may be present before operation or may be exacerbated by an high mortality risk (group C; mortality, 2.4%). These findings operation. The term pickwickian syndrome (which derives suggest that the OS-MRS is a valuable tool that can be from The Posthumous Papers of the Pickwick Club, by Charles effectively used to stratify risk and facilitate surgical decision Dickens) was resurrected from the late 1800s to describe a making and patient discussion regarding bariatric surgery. morbidly obese 52-year-old man who fell asleep in a poker Although the morbidly obese patient is certainly at greater game while holding a hand containing a full house.11 He was risk, this risk can be markedly reduced by paying careful taken to the hospital by friends who presumed he was ill. attention to detail in preoperative and postoperative care. The The pickwickian syndrome is now known to comprise two increased risks encountered in these patients include wound pulmonary syndromes associated with morbid obesity: SAS infection, dehiscence, thrombophlebitis, pulmonary embolism and OHS.12 (PE), anesthetic calamities, acute postoperative asphyxia in patients with obstructive sleep apnea syndrome (SAS), acute Sleep Apnea Syndrome respiratory failure, right ventricular or biventricular cardiac SAS is a potentially fatal complication of morbid obesity. failure, and missed acute catastrophes of the abdomen (e.g., A diagnosis of SAS should be suspected when there is a DOI 10.2310/7800.2008.S05C07 05/08
  2. 2. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 5 GI TRACT AND ABDOMEN 7 SURGICAL TREATMENT OF MORBID OBESITY — 2 history of loud snoring, frequent nocturnal awakening with or have additional pulmonary problems, such as asthma, shortness of breath, and daytime somnolence. It is estimated sarcoidosis, idiopathic pulmonary fibrosis, or recurrent PE. that 2% of middle-aged women and 4% of middle-aged men One study of patients who underwent operation for morbid in the US workforce have SAS, and the incidence is markedly obesity showed no statistically significant difference in weight higher in the severely obese.13 Patients will often admit to between those who had OHS and those who did not.12 falling asleep while driving and waking up with their car on Chronic, severe hypoxemia is associated with three com- the road’s median strip or bumping its guardrail. It is plications that put patients with OHS at risk: polycythemia, extremely important that trauma surgeons be aware of the pulmonary arterial vasoconstriction, and pulmonary hyper- relation between obesity and somnolence should a morbidly tension. The polycythemia further increases the already signifi- obese patient be seen in the emergency department after an cant risk of venous thrombosis and PE. If the hemoglobin automobile accident in which he or she fell asleep at the (Hb) concentration is 16 g/dl or greater, phlebotomy to a wheel. Patients with SAS suffer from repeated attacks of concentration of 15 g/dl should be performed to reduce the upper airway obstruction during sleep. The cause is probably postoperative risk of venous thrombosis. If the pulmonary related to a large, fat tongue, as well as to excessive fat depo- arterial pressure (PAP) is 40 mm Hg or higher, consideration sition in the uvula, pharynx, and hypopharynx. The normal should be given to prophylactic insertion of an IVC filter genioglossus reflex is depressed, but this depression may be because of the high risk of a fatal pulmonary embolism in secondary to the excessive weight of the tongue. These these patients.16 Placement of an IVC filter can be a challenge patients are notorious snorers. As a result of inadequate stage because the appropriate landmarks cannot be identified in IV and rapid eye movement (REM) sleep, they are markedly the operating room with fluoroscopy. It is necessary, before somnolent during the day. operation, to tape a quarter to the patient’s back over the Patients with SAS are at high risk for acute upper airway second lumbar vertebra with the aid of fixed radiographs obstruction and respiratory arrest when undergoing an opera- and then, during operation, to aim for the quarter with the tion and general anesthesia. Therefore, any patients with sus- insertion catheter, using fluoroscopy. Because these patients pected SAS should undergo preoperative polysomnography are usually too heavy for angiography tables, the filter at a sleep center to confirm the diagnosis. Medications are usually cannot be inserted percutaneously in the radiology usually ineffective. Stimulants, such as methylphenidate department. hydrochloride (Ritalin), should not be used. If a patient has Chronic hypoxemia also leads to pulmonary arterial vaso- a respiratory disturbance index (RDI) greater than 25— constriction and severe pulmonary hypertension and eventu- indicating more than 25 apneic or hypopneic episodes per ally to right-side heart failure or cor pulmonale with neck hour of sleep—or has cardiac dysrhythmias in association vein distention, tricuspid valvular insufficiency, right upper with apnea, treatment by nocturnal nasal continuous positive quadrant tenderness secondary to acute hepatic engorge- airway pressure (nasal CPAP) should be provided. With ment, and massive peripheral edema.17,18 Such patients may this technique, air flowing through a nasal mask against a also have a significantly elevated pulmonary artery wedge constant airway resistance enters the nasal pharynx and pressure (PAWP), which suggests left ventricular dysfunc- pushes the tongue forward to prevent recurrent obstruction.14 tion.17 Morbidly obese patients with a history of pulmonary The pressure can be adjusted for each patient. Unfortunately, disease or a BMI greater than 50 kg/m2 should have pre- many patients cannot tolerate the device, because it is cum- operative determinations of blood gas values. If arterial bersome and noisy and tends to dry out the upper airway, blood gas (ABG) measurement reveals severe hypoxemia though dryness can be prevented with an inexpensive room (i.e., arterial oxygen tension [PaO2] f55 mm Hg), severe humidifier. If the patient has severe SAS with an RDI greater hypercapnia (arterial carbon dioxide tension [PaCO2] g47 than 40 and does not respond with elimination of the apneic mm Hg), or both, the patient should undergo Swan-Ganz episodes or cannot tolerate nasal CPAP, a tracheostomy catheterization. If the PAWP is 18 mm Hg or greater, intra- should be considered. An extra-long tracheostomy tube is venous furosemide should be administered for diuresis before usually necessary because of the depth of the trachea in the elective operation. However, some patients may require a morbidly obese patient. high ventricular filling pressure. A low cardiac output and hypotension may follow diuresis, necessitating volume Obesity Hypoventilation Syndrome reexpansion. OHS is a condition associated with morbid obesity in which It is highly probable that some of the elevated PAP and a person suffers from hypoxemia and hypercapnia when PAWP measurements are caused by the increased IAP in the breathing room air while awake but resting.15 Spirometry morbidly obese patient [see Figure 2]).19,20 The high IAP leads reveals decreases in forced vital capacity, residual lung to an elevated diaphragm, which in turn increases intrapleural volume, expiratory reserve volume, functional residual capa- pressure and thereby PAP and PAWP; if the pleural pressure city, and maximum minute volume ventilation, usually with- is measured with an esophageal transducer, the transmyocar- out obstruction of airflow [see Figure 1]. The most profound dial pressure can be estimated. For this reason, these patients decrease is that in expiratory reserve volume; it is probably may require a markedly elevated PAWP to maintain an secondary to increased IAP and a high-riding diaphragm. adequate cardiac output, and excessive diuresis may lead to Thus, these patients have a restrictive rather than an obstruc- hypotension. The same reasoning may be applied to a patient tive pulmonary disease. The decreased expiratory reserve with a distended abdomen resulting from peritonitis and pan- volume implies that many alveolar units are collapsed at end- creatitis in whom what seem to be unusually high cardiac expiration, which leads to perfusion of unventilated alveoli, filling pressures are necessary. Therefore, one must rely or shunting. Patients with OHS often are heavy smokers on relative changes in cardiac output in response to either 05/08
  3. 3. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 5 GI TRACT AND ABDOMEN 7 SURGICAL TREATMENT OF MORBID OBESITY — 3 100 Figure 1 Impaired pulmonary function in the morbidly * * obese improved * * * significantly 80 after weight loss (% of predicted Value) Pulmonary Function * induced by gastric operation.12 60 ERV = expiratory reserve volume; FEV1 = forced expiratory volume in one second; FRC 40 = functional residual capacity; FVC = forced vital capacity; MVV = 20 maximal voluntary ventilation; TLC = FVC FEV1 MVV ERV FRC TLC total lung capacity. Before Operation After Weight Loss *p < .01 Compared with Preoperative Values volume challenge or diuresis to determine the optimal PAWP open upper abdominal operations, when patients experience in morbidly obese patients. a decrease in incisional pain.21 Patients with OHS respond rapidly to supplemental oxygen. It is important to emphasize that morbidly obese patients, However, oxygen administration is occasionally associated especially those with respiratory insufficiency, should be with significant CO2 retention, which necessitates intubation placed in the reverse Trendelenburg position to maximize and mechanical ventilation. Because their pulmonary disease diaphragmatic excursion and to increase residual lung is restrictive rather than obstructive, these patients are usually volume.22 These patients will often complain of air hunger easy to ventilate without high peak airway pressures. ABG and respiratory distress when they lie supine. So-called break- measurements need not return to normal values before ing of the bed at the waist may exacerbate the problem extubation; it is only necessary that they return to their by pushing the abdominal contents into the chest, thereby preoperative values. These values are achieved early after raising the diaphragm and further reducing lung volumes. laparoscopic procedures and, on average, 4 days after major Placing these patients in the leg-down position may predis- pose them to venous stasis, phlebitis, and PE; this tendency should be offset with intermittent venous compression boots [see Thrombophlebitis, Venous Stasis Ulcers, and Pulmonary 4.5 35 Embolism, below].23 Both SAS and OHS can be completely corrected with Wedge Pressure (mm Hg) Cardiac Index (L/min/m2) weight reduction after gastric operation for morbid obesity: 3.5 * 25 the nocturnal apneas resolve, the PaO2 rises, and the PaCO2 * falls to normal as lung volumes improve.12 *   2.5 15 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 RESUS of this increased risk for cardiac dysfunction, preoperative 1.5 5 electrocardiography should be performed on all obese patients 0 5 10 15 20 25 30 30 years of age or older. Abdominal Pressure (mm Hg above Baseline) Cardiac dysfunction in the morbidly obese patient is Cardiac Index Wedge Pressure usually associated with respiratory insufficiency of obesity, *p < .05 versus Baseline especially OHS.11 An elevated PAP in these patients may be secondary to hypoxemia-induced pulmonary arterial vaso- Figure 2 In a porcine model, raising intra-abdominal pressure (IAP) caused cardiac index to fall and pulmonary constriction, to elevated left atrial pressures secondary to left artery wedge pressure (PAWP) to rise. At an IAP of 25 mm ventricular dysfunction, or to a combination of these; it may Hg, saline was given to restore intravascular volume; cardiac also be secondary to the increased pleural pressures arising index returned to baseline levels, but PAWP remained from an elevated diaphragm secondary to increased IAP.17,20,23 elevated.20 It is unusual for morbidly obese patients without respiratory 05/08
  4. 4. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 5 GI TRACT AND ABDOMEN 7 SURGICAL TREATMENT OF MORBID OBESITY — 4 insufficiency to experience significant cardiac dysfunction in and at appropriate intervals thereafter (depending on the the absence of severe coronary artery disease. Morbidly obese type of heparin used) for at least 2 days or until the patient patients often have systemic hypertension, which can aggra- is ambulatory. Because respiratory function in the morbidly vate left ventricular dysfunction; however, mild left ventricu- obese patient is greatly enhanced with the reverse Trendelen- lar dysfunction can be documented in many morbidly obese burg position, intermittent sequential venous compression patients in the absence of systemic hypertension.24,25 Circulat- boots should be used to counteract the increased venous ing blood volume, plasma volume, and cardiac output increase stasis and the propensity for clotting. It is important that in proportion to body weight.25 Massively obese patients may the intermittent venous compression boots be used before occasionally present with acute heart failure: it is reasonable induction of anesthesia and throughout the operative proce- to assume that the enormous metabolic requirements of such dure. Such boots are usually part of a standard preoperative patients can present a greater demand for blood flow than protocol in gastric procedures for weight control; their use the heart can provide. Vigorous diuresis often corrects such should not be unintentionally neglected in preparation for acute heart failure. Significant weight loss corrects pulmonary other elective or emergency procedures on morbidly obese hypertension [see Figure 3], as well as the left ventricular patients. Patients with severe venous stasis disease (e.g., dysfunction associated with respiratory insufficiency.17,26 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 Morbidly obese individuals have difficulty walking, tend to attempt to walk during the evening after operation. Bariatric be sedentary, have a large amount of abdominal weight rest- surgery–induced weight loss will correct the venous stasis ing on their IVC, and have increased intrapleural pressure disease in most cases.29 (which impedes venous return).18,20 All of these conditions Venous stasis ulcers can be quite difficult to treat in a thin increase the tendency toward phlebothrombosis. Patients are person; they are almost impossible to cure in a patient with most at risk when immobilized in the supine position for long morbid obesity [see Figure 4]. The most important goal in periods in the OR. These patients have been shown to have the management of these ulcers is weight loss, which almost low levels of antithrombin, which may increase their tendency invariably leads to healing of the ulcer, probably as a result of toward venous thrombosis.27 It has also been suggested that decreased IAP.29 starvation, particularly in the postoperative period, may be  associated with high levels of free fatty acids, which may pre- dispose to perioperative thrombotic complications.28 Patients Approximately one third of morbidly obese patients either with severe OHS often have a noticeably elevated PAP, which have had a cholecystectomy or may have had gallstones noted can lead to right-side heart failure and can increase the risk at the time of another intra-abdominal operative procedure of venous stasis and thrombosis. Investigators have noted that (e.g., a gastric operation for morbid obesity). Preoperative patients with primary idiopathic pulmonary hypertension are evaluation of the gallbladder may be technically quite difficult at significant risk for fatal PE.13 in morbidly obese patients because ultrasonography may The risk of deep vein thrombosis (DVT) increases with fail to visualize gallstones. Intraoperative ultrasonography a prolonged operation or a postoperative period of immobili- is probably much more accurate. Should symptomatic gall- zation, and it increases even further in the morbidly obese stones be present in a patient undergoing a gastric procedure patient. Standard or low-molecular-weight heparin should be for obesity, the gallbladder should be removed if the surgeon administered subcutaneously 30 minutes before operation judges it safe to perform this additional procedure. If 80 Pulmonary Arterial Pressure (mm Hg) 70 60 50 40 30 20 10 0 Before 3–9 Months Operation after Operation Figure 3 Mean pulmonary arterial pressure was signifi- Figure 4 This chronic venous stasis ulcer was present for cantly improved in 18 patients 3 to 9 months after gastric several years in a morbidly obese patient. Healing followed surgery–induced weight loss of 42% P19% of excess weight. weight loss induced by a gastric operation. 05/08
  5. 5. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 5 GI TRACT AND ABDOMEN 7 SURGICAL TREATMENT OF MORBID OBESITY — 5 placement of an adjustable gastric band is contemplated, the and sodium pentobarbital induction. One person elevates the cholecystectomy should be undertaken first and the indwell- jaw, hyperextends the neck, and ensures a tight fit of the ing device placed only in the absence of intra-abdominal bile mask, using both hands. To ensure adequate oxygen delivery, spillage during the procedure. a second person compresses the ventilation reservoir bag, In past studies, rapid weight loss led to the development using two hands because of the resistance to air flow from of gallstones in 25 to 40% of patients who underwent GBP. the poorly compliant, heavy chest wall. After ventilation with The risk of cholelithiasis in this setting can be reduced to 100% oxygen for several minutes, intubation is attempted. 2% by administering ursodeoxycholic acid, 300 mg orally If difficulties are encountered within 30 seconds, the steps twice daily.30 Laparoscopic cholecsytectomy at the time of above should be repeated until the patient has been suc- laparoscopic gastric bypass can be technically challenging; cessfully intubated. A volume ventilator is required during consequently, many surgeons prefer to take an expectant operation. Placing the patient in the reverse Trendelenburg approach to the gallbladder rather than complicate the bar- position expands total lung volume and facilitates ventila- iatric procedure with a simultaneous cholecystectomy (unless tion22; however, the reverse Trendelenburg position increases cholecystectomy is clearly indicated in a particular patient). 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 Pseudotumor cerebri is an unusual complication of morbid or a digital pulse oximeter. obesity that is associated with benign intracranial hyperten-       sion, papilledema, blurred vision, headache, and elevated  cerebrospinal fluid pressures.31 It has been our experience that patients with pseudotumor cerebri are not at any addi- Bariatric surgical procedures, like most other general surgi- tional perioperative risk and that CSF need not be removed cal procedures, have undergone a transition from an open before anesthesia and major abdominal operations. There is approach to one that places more emphasis on minimally some theoretical concern that gastrointestinal contamination invasive or laparoscopic techniques. Laparoscopic GBP was during GBP may cause shunt infection in patients who have first described in 1994 and became widely accepted in 1999, been previously treated with indwelling shunts to relieve though it was not until 2004 that, according to a national elevated CSF pressures. Successful weight reduction cures audit of bariatric surgery performed at academic centers, the pseudotumor cerebri.32,33 number of laparoscopic GBP procedures performed exceeded the number of open GBP procedures.   At present, the laparoscopic approach to GBP is favored Degenerative osteoarthritis of the knees, hips, and back is because it achieves a comparable degree of weight loss a common complication of morbid obesity. Weight reduction while possessing some notable advantages over its open coun- alone may greatly reduce the pain and immobility that afflict terpart.21 Open GBP is performed through an upper midline these patients. In some cases, the damage may be so extensive incision, whereas laparoscopic GBP is performed through five that a total joint replacement is desirable; however, joint or six small incisions. Abdominal wall retractors and mechan- replacement in patients who weigh more than 250 lb is ical retraction of the abdominal viscera, which are necessary associated with an unacceptable incidence of loosening.34 for adequate exposure during an open procedure, are not Weight reduction by means of a gastric bariatric operation required during a laparoscopic procedure, which makes use may be the most sensible initial approach, to be followed by of gas insufflation (for pneumoperitoneum) and the effects joint replacement after weight loss if pain and dysfunction of body positioning and gravity to facilitate intraoperative persist. exposure. With the elimination of the large surgical incision and mechanical retraction, the laparoscopic GBP patient experiences less operative trauma, less postoperative pain, Operative Planning and fewer wound-related complications. In addition, laparo- scopic GBP yields less impairment of immediate postopera-      tive pulmonary function and a lower systemic stress response.  A 2007 study of 22,422 patients who underwent Roux-en-Y Morbidly obese patients can be intimidating to the anes- GBP for treatment of morbid obesity compared the outcomes thesiologist because they are at significant risk for com- of laparoscopic procedures (n=16,357) with those of open plications from anesthesia, especially during induction. The procedures (n=6,065).35 The mean length of hospital stay risk is particularly great for obese patients with respiratory was significantly lower in the laparoscopic group (2.7 days insufficiency. An obese patient often has a short, fat neck and versus 4.0 days), as were the overall complication rate (7.4% a heavy chest wall, which make intubation and ventilation versus 13.0%), the 30-day readmission rate (2.6% versus a challenge. If endotracheal intubation proves difficult, 4.7%), the in-hospital mortality (0.1% versus 0.3%), and the however, such a patient can usually be well ventilated with a mean cost ($13,743 versus $14,585 [US]). 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 The gastric operations performed for morbid obesity personnel be present during induction and intubation for include both GBP procedures and gastric restrictive proce- patients with respiratory insufficiency of obesity. An oral dures (i.e., gastroplasty and gastric banding). Randomized, airway is inserted after muscle paralysis with succinylcholine prospective trials have conclusively shown that GBP is as 05/08
  6. 6. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 5 GI TRACT AND ABDOMEN 7 SURGICAL TREATMENT OF MORBID OBESITY — 6 effective for weight control as the malabsorptive jejunoileal has been associated with a high incidence of deficiencies of (JI) bypass is, while resulting in significantly fewer complica- fat-soluble vitamins, hypocalcemia-induced osteoporosis, and tions.36,37 JI bypass is associated with a substantial incidence protein-calorie malnutrition.50 These nutritional deficiencies of both early complications (e.g., acute cirrhosis, electrolyte may be more common in the United States, where fat intake imbalance, and fulminant diarrhea)38 and late complications is high, than in many other countries. In Italy, for example, (e.g., cirrhosis, interstitial nephritis, arthritis, enteritis, neph- starch intake (as in pasta) probably outstrips fat intake; still, rocalcinosis, and recurrent oxalate renal stones).39 If evidence a number of Italian patients have had to be readmitted for of cirrhosis, renal failure secondary to interstitial nephritis, or parenteral nutrition and extension of the common absorptive other complications mandates reversal of a JI bypass, the intestinal tract because of refractory malnutrition. In some patient, if not extremely ill, should be converted to a GBP; patients, it might be possible to convert a failed proximal otherwise, all the lost weight is sure to be regained, and the GBP into a modified BPD with a 150 cm absorptive obesity-related comorbidity will return. Admittedly, however, ileal limb (a procedure often referred to as distal GBP); how- some patients have done well after JI bypass and do not need ever, these patients must also be monitored carefully for to have the operation reversed. deficiencies of fat-soluble vitamins, for osteoporosis, and for Several randomized, prospective trials have found that hor- malnutrition. izontal gastroplasty yields poorer results than GBP.40-42 Fail- Superobese patients—defined as those whose weight is ure of horizontal gastroplasty has generally been attributed to 225% of ideal body weight or greater or whose body mass technical causes (e.g., enlargement of the proximal pouch or index (BMI) is 50 kg/m2 or higher—will lose, on average, the stoma or disruption of the staple line). Vertical banded only about half of their excess weight, rather than two-thirds, gastroplasty (VBG) was developed in the hope that it would after standard GBP. In these patients, a 150 cm proximal solve these technical problems and yield weight loss compa- Roux-en-Y procedure (so-called long-limb GBP [see Open rable to that seen after GBP without incurring the significant Proximal Gastric Bypass, Operative Technique, below]) risk of iron, calcium, and vitamin B12 deficiencies associated may increase weight loss in the first few years after operation with GBP. In the 1990s, a procedure known as adjustable without causing an increase in nutritional complications.51 silicone gastric banding was developed, which involved placement of a restrictive ring around the proximal stomach In choosing the appropriate surgical approach, it is impor- to create a small gastric pouch. In this restrictive procedure, tant to take into account the tremendous surgical revolution which can be done laparoscopically in the vast majority that laparoscopy has brought about in the treatment of morbid of patients, weight loss can be enhanced and vomiting obesity. Now that every operation performed to treat obesity minimized by adjusting the ring diameter via transcutaneous can be done laparoscopically, laparoscopic bariatric surgery access to the subcutaneous reservoir. is not only common but, in many centers, predominant. Although VBG and, presumably, other restrictive proce- For this reason, as well as because laparoscopic obesity treat- dures appear to be excellent from a technical point of view,43 ment requires advanced technical skills, minimally invasive multiple randomized, prospective trials have found such bariatric procedures have become a cornerstone of training approaches to be significantly less effective than standard for surgeons now learning laparoscopic surgery. GBP. In one comparison trial, patients addicted to sweets lost much more weight after GBP than after VBG because Vertical Banded Gastroplasty 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 The first step in VBG is to make a circular stapled opening candy or drinking nondietetic sodas. Subsequent random- in the stomach 5 cm from the esophagogastric junction. A ized, prospective trials confirmed the superiority of GBP.45,46 90 mm bariatric stapler with four parallel rows of staples is Furthermore, maintenance of successful weight loss after then applied once between this opening and the angle of His. GBP appears to continue for as long as 14 years after opera- (At this point, according to Mason, the originator of the tion: in the average patient, weight loss amounts to about two-thirds of excess weight at 1 to 3 years after operation, procedure, the volume of the pouch should be measured by three-fifths at 5 years, and more than half in years 5 through means of an Ewald tube placed by the anesthetist; ideally, 10.47,48 It has been suggested that standard (i.e., proximal) pouch volume should be 15 ml.) GBP will fail in 10 to 15% of patients because these patients Next, a strip of polypropylene mesh is wrapped around the will frequently nibble on high-fat snacks (e.g., corn chips, gastrogastric outlet on the lesser curvature and sutured to potato chips, and buttered popcorn). Such patients may have itself—but not to the stomach—in such a way as to create to be converted to a combined restrictive and malabsorptive an outlet with a circumference of 5 cm for the small upper procedure, such as partial biliopancreatic diversion (BPD).49 gastric pouch [see Figure 5a]. Some surgeons have used a The original BPD procedure involves hemigastrectomy and stomal outlet 4.5 cm in circumference, but this smaller outlet anastomosis of the distal 250 cm of intestine to the stomach; has not led to better weight loss; in fact, many patients the bypassed small intestine is reanastomosed to the ileum with the 4.5 cm outlet exhibit maladaptive eating behavior, 50 cm from the ileocecal valve. BPD with duodenal switch is drinking high-calorie liquids because meat tends to get caught a variant of the original procedure in which a linear gastric in the small stoma. tube based on the lesser curvature is created (sleeve gastrec- Silastic ring gastroplasty [see Figure 5b] is a variant of VBG tomy), with the pylorus left intact, and an ileal Roux limb is that uses a vertical staple line and a stoma reinforced with brought up for anastomosis to the proximal duodenum. BPD Silastic tubing. 05/08
  7. 7. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 5 GI TRACT AND ABDOMEN 7 SURGICAL TREATMENT OF MORBID OBESITY — 7 a b Figure 5 Vertical banded gastroplasty (VBG). Depicted are (a) standard VBG and (b) Silastic ring gastroplasty, a variant of VBG in which the stoma is reinforced with a Silastic tube.  Laparoscopic Adjustable Gastric Banding Complications of VBG include erosion of the polypro- Gastric banding is another form of gastroplasty, in which a pylene mesh used to restrict the gastroplasty stoma into the synthetic band is placed around the stomach just below the gastric lumen, enlargement of the pouch, stomal stenosis, esophagogastric junction. In several series, gastric banding reflux esophagitis, and mild vitamin deficiencies.52 To date, has yielded markedly variable results with respect to achieve- mesh erosion has been infrequently observed after VBG. ment of weight loss. Furthermore, it has been associated with Pouch enlargement is fairly common with horizontal gastro- slipping or kinking of the banded stoma, obstruction at the plasty but is much less likely to occur with VBG, in which the band, and intractable vomiting. vertical staple line is placed in the thicker, more muscular Laparoscopic adjustable gastric banding (LAGB) is signifi- part of the stomach. In addition, stomal diameter remains cant advance over open gastric banding procedures, primarily fixed with the mesh band. If mesh erosion, pouch enlarge- because of the adjustability of the band. Open gastric banding ment, stomal stenosis, disabling GI reflux, or recurrent procedures have used a variety of materials to constrict the vomiting occurs, it is probably best to convert the patient to gastric lumen and carry a recognized risk of postoperative GBP. In particular, patients with a Silastic ring VBG may nausea and vomiting that do not respond to any treatment exhibit intractable vomiting of solid foods with no evidence short of reoperation. The adjustable gastric bands available of mechanical obstruction. In our experience, conversion of for use in LAGB [see Figure 6] are silicone devices with an these patients to GBP yields good results and eliminates inflatable reservoir that can be inflated or deflated postopera- the vomiting problem. Finally, vitamin deficiencies can tively through a subcutaneous port placed deep in the abdom- usually be prevented by having VBG patients take a standard inal wall for percutaneous access. Saline is injected into or multivitamin daily for life. withdrawn from the reservoir to adjust gastric luminal diam- eter. 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 Figure 6 Laparoscopic adjustable gastric banding. Shown is 39% and a mean overall loss of 18% of baseline body weight. the adjustable gastric banding device used in the procedure. However, 28% of patients lost less than 10% of their initial 05/08
  8. 8. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 5 GI TRACT AND ABDOMEN 7 SURGICAL TREATMENT OF MORBID OBESITY — 8 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 place- ment 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 Figure 7 Laparoscopic adjustable gastric banding. Once in hospitalization were significantly shorter in LAGB patients. the correct position on the proximal stomach, the adjustable Complication rates and reoperation rates were similar in the band is locked into place. 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, buckle—so as to hold the device in position. The band tubing compared with 39% for LAGB patients. Thereafter, weight is brought through the left midclavicular trocar port, which is loss slowed, remaining nearly unchanged at 3 years (63%). placed via the left midclavicular line subcostal trocar incision Patients who underwent LAGB initially lost weight more slowly, but the ongoing weight loss was continuous, eventu- and fixed to the abdominal wall fascia with sutures. The ally approaching that of LRYGB. At 3 years, the %EBWL for tubing is connected to the reservoir, which is filled with LAGB patients was 55%. saline.    LAGB is performed by using a five-port technique. Initial It is essential to place the band properly during the initial abdominal access is obtained via a supraumbilical trocar, and procedure. The results to date suggest that the proximal the remaining ports are placed sequentially along the right pouch must be very small to optimize weight loss. In and left costal margins. The liver is retracted via the subxi- addition, proper placement minimizes—though it does not phoid port, and the proximal stomach is visualized with a eliminate—the risk of band slippage and the complications laparoscope inserted through the umbilical port. thereof. Subsequent steps are done according to the pars flaccida Several techniques have been suggested for posterior technique. A retrogastric tunnel for band insertion is created fixation of the band, but they are more difficult than anterior at the posterior confluence of the diaphragmatic crura in a fixation techniques. With the pars flaccida technique, plane of dissection that is easily developed with minimal posterior fixation of the band is not necessary to prevent band blunt dissection after electrocauterization of the peritoneal slippage. Anterior fixation, however, is routinely performed, membrane. This tunnel is placed cephalad to the posterior with interrupted sutures of nonabsorbable material placed peritoneal reflection, so that the free space of the lesser sac between the distal and the proximal stomach to allow tissue posterior to the stomach is not entered. Additional dissection to be apposed over the band and held in place. is then carried out laterally at the angle of His to open the Although LAGB appears easier than many of the proce- peritoneum and start clearing a plane behind the proximal dures done to treat obesity, there is a definite learning stomach. curve. A number of surgical misadventures have been A specially designed implement is inserted behind the reported, including gastric perforation, splenic injury, and stomach from the lesser curvature to the angle of His and malpositioning of the band. 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 Band slippage (anterior, posterior, or concentric) may [see Figure 7]. Gastrogastric sutures are placed to create a occur even after proper placement, resulting in intolerance of tunnel of stomach overlying the banding device—but not the oral intake and vomiting. Such complaints are an indication 05/08
  9. 9. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 5 GI TRACT AND ABDOMEN 7 SURGICAL TREATMENT OF MORBID OBESITY — 9 for an upper GI series, which usually reveals dilatation of the   proximal pouch and rotation of the band [see Figure 8]. Initial How successful LAGB is at achieving weight loss over the treatment consists of evacuating all saline from the band. long term remains unclear. The adjustability and reversibility Frequently, however, the proximal pouch does not return of the operation, as well as the decreased disability that to its normal size, and symptoms recur or fail to resolve. results, make it attractive to both patients and physicians. Laparoscopic or open revision of the banding procedure is The procedure appears to avoid some of the major post- then required; if the patient also has not lost a sufficient operative complications associated with open GBP (e.g., amount of weight, conversion to GBP may be recommended. incisional hernia, marginal ulcer, and stomal stenosis). Band It is noteworthy that band erosion into the stomach, a not slippage remains a major postoperative concern, however, infrequent complication of the use of mesh in VBG or in the though the incidence of slippage does appear to decrease as Angelchik prosthesis for gastroesophageal reflux treatment, the surgeon’s experience with the procedure increases. More has not been frequently reported. Longer follow-up is significant, there appears to be a high frequency of failed necessary to evaluate the true extent of this risk. weight loss—as high as 15 to 20% of all patients undergoing As after any form of gastroplasty, the patient may fail to the procedure and possibly even higher. European data lose weight or may regain lost weight. Inappropriate eating confirm that there is a significant failure rate but also suggest behaviors (e.g., intake of high-calorie sweets) are the most that the remaining patients achieve a degree of weight loss likely cause. If obesity-related comorbid conditions persist, approaching that seen with proximal GBP. Whether these conversion to proximal GBP is appropriate. reports will withstand the scrutiny of long-term follow-up remains to be seen. Open Proximal Gastric Bypass a Proximal GBP results in greater weight loss than the gastric restrictive procedures (see above) and carries a lower inci- dence 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 super- imposed 55 or 90 mm staple lines are placed across the prox- imal 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 laparoscopi- cally, but an isolated gastric pouch is created with stapled transection of the stomach.   b 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 pro- cess 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 aggres- sive 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, includ- ing examination of the liver for possible signs of liver disease. Other incidental findings may become apparent as well. Figure 8 Laparoscopic adjustable gastric banding. Contrast Troubleshooting Unexpected significant liver disease is studies illustrate (a) a normally positioned laparoscopic occasionally discovered at the time of operation. If the patient adjustable gastric band and (b) a slipped band. has cirrhosis without portal hypertension, one should perhaps 05/08
  10. 10. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 5 GI TRACT AND ABDOMEN 7 SURGICAL TREATMENT OF MORBID OBESITY — 10 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 gastro- hepatic omentum and the lateral angle of His, which is identified by the encircling rubber drain. The blunt tip of a Figure 9 Open proximal gastric bypass. Depicted is the large 28 French red rubber tube is placed behind the stomach completed procedure. in a medial-to-lateral direction along this dissected path to encircle the stomach [see Figure 10]. The open end of the red proceed with bypass if the patient’s comorbid conditions rubber tube is subsequently brought through the previously make it mandatory; liver transplantation carries increased created mesenteric opening with a large right-angle clamp. risk in morbidly obese patients. The gallbladder should be The stomach is now ready for stapling, and the red rubber palpated for gallstones, which, if found, may be an indication tube serves as a guide for introduction of the stapler. At this for cholecystectomy at the time of the bypass procedure. If point, all intraluminal tubes and devices (e.g., the nasogastric there are no visual or palpable gallbladder abnormalities, tube and the esophageal stethoscope) are removed from the intraoperative ultrasonography may be used to examine the esophagus by the anesthetist. gallbladder. It is not unusual to discover other previously unrecognized Troubleshooting When a tube is inadvertently stapled conditions during GBP, primarily because symptoms may within the stomach, excising it from the nontransected 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 subse- quent blunt mobilization of the distal esophagus. To prevent esophageal injury, the nasogastric tube is carefully palpated within the lumen of the esophagus during mobilization, Figure 10 Open proximal gastric bypass. After dissection of and blunt dissection proceeds widely around this important the avascular tissue on the posterior gastric wall, a red rubber landmark. Laterally, dissection must be at the level of the catheter is passed through the resulting space to encircle the esophagus or higher. stomach. 05/08
  11. 11. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 5 GI TRACT AND ABDOMEN 7 SURGICAL TREATMENT OF MORBID OBESITY — 11 gastric staple line can be a technical challenge. To remove the stapled tube, it is generally necessary to use a stapler to tran- sect 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 some- what more distally to enhance mobilization of what will become the Roux limb if the mesentery appears foreshort- ened—at which point the jejunum is divided with a stapler. An 8 to 12 cm segment of jejunum may be resected at this Figure 11 Open proximal gastric bypass. The stomach is point to create a larger mesenteric defect, which should stapled to create the small proximal pouch. The stapler is facilitate mobilization of the limb to the proximal stomach. fired three times to create three superimposed staple lines, Mesenteric dissection is carried posteriorly in fat with the thereby decreasing the risk of staple line disruption. 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 A 1 cm anastomosis is created between the proximal stom- Roux limb). ach pouch and the Roux limb. We prefer a handsewn anas- A side-to-side jejunojejunostomy is then created with a tomosis for this procedure, using an outer layer composed 60 mm linear stapler at least 45 cm beyond the initial point of interrupted 2-0 or 3-0 silk sutures and an inner layer of jejunal division for standard proximal GBP. Some sur- composed of a continuous absorbable 3-0 polyglycolic acid geons perform this anastomosis 150 cm downstream for the (Dexon) suture. When the posterior aspect of the anastomo- long-limb modification of the procedure used in superobese sis is complete, a 30 French dilator is placed orally by the patients [see Operative Planning, Choice of Surgical Proce- anesthetist and is guided through the anastomosis by the sur- dure, above] or even further distally for the distal GBP geon to ensure that the stoma has the appropriate diameter modification, which greatly enhances malabsorption. It is [see Figure 12]. The anterior aspect of the anastomosis is then important not to narrow the efferent lumen at the jejunoje- completed. junostomy site, particularly with the longer-limb modifica- tions, in which the lumen at the distal end of the Roux limb Troubleshooting A significant concern for many bariat- may be quite small. The enterotomies made to allow place- ric surgeons has been a high incidence of staple line disrup- ment of the stapler can usually be closed with a 55 mm tion causing failed weight loss or weight regain; in one series, stapler loaded with 3.5 mm staples; however, if stapling the incidence of such disruption was 35%. To minimize would cause undue narrowing of the lumen, the closures this risk, some surgeons advocate transecting the stomach. should be handsewn instead. Currently, this step is routinely carried out as part of a 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 stom- ach, 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 posi- tioned red rubber tube. Once it is determined that the staple line will reach completely across the stomach and that the Figure 12 Open proximal gastric bypass. When the posterior stomach is not folded on itself, the stomach is stapled aspect of the gastrojejunal anastomosis has been completed, a three times in such a way that the three staple lines are 30 French dilator is placed through the stoma to confirm that superimposed [see Figure 11]. the opening is correctly sized. 05/08
  12. 12. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 5 GI TRACT AND ABDOMEN 7 SURGICAL TREATMENT OF MORBID OBESITY — 12 laparoscopic GBP. In an open GBP, one may transect the feeding if a fistula develops. Fortunately, such fistulas are stomach either by applying a linear cutting stapler with 3.5 or rare. When they do occur, they often heal if (1) they are well 4.8 mm staples (depending on the estimated gastric wall drained, (2) there is no distal obstruction or local abscess, thickness) or by inserting two parallel noncutting transverse and (3) the patient is receiving nutritional support with no anastomosis (TA)–90 staplers and cutting between them with oral intake. A gastrostomy tube should also be placed in the a scalpel after the staplers are fired. Other surgeons, however, distal gastric pouch when extensive adhesions from a previous prefer to leave the stomach undivided and oversew the staple procedure or a difficult gastric reoperation increase the risk of line. In our version of open GBP, we find that placing three postoperative gastric distention. or four precisely superimposed staple lines reduces the incidence of staple line disruption to less than 2%. Step 7: Closure Another advantage of gastric transection besides reduction When the absence of leakage is confirmed or when any of staple line disruption is that it allows the Roux limb to leaks identified have been controlled, the tip of the nasogas- be brought up to the gastric pouch via a retrocolic and retro- tric tube may be positioned further down in the Roux limb gastric tract, which is substantially shorter and places less and left to continuous suction overnight. All mesenteric tension on the limb. This approach is particularly helpful defects—at the jejunojejunostomy, at the mesocolon, and in severely obese patients with a fatty and foreshortened behind the Roux limb (Peterson hernia)—are then closed mesentery, in whom it is difficult to free the Roux limb to prevent an internal hernia. The abdominal fascia is reap- sufficiently to reach the proximal stomach without tension. proximated with a continuous double-looped No. 2 suture, The possibility that gastric transection may prove helpful subcutaneous tissues are irrigated with a crystalloid solution, in a specific patient is another reason why it is advisable to and the skin is closed with skin staples. No subcutaneous delay stapling the stomach until the Roux limb has been sutures or drains are used in routine cases. mobilized.  Step 6: Assessment of Anastomosis Proximal GBP is associated with a significant incidence When the entire anastomosis is complete, the dilator is of stomal stenosis and with marginal ulcer.55 The former removed and an 18 French nasogastric tube is advanced by responds to endoscopic stomal dilatation, and the latter the anesthetist while the tip is carefully guided through the usually responds to proton pump inhibitor (PPI) therapy. anastomosis by the surgeon. The Roux limb is occluded with Addition of sucralfate to this regimen may be helpful. The the assistant’s left hand or with an atraumatic intestinal risk of marginal ulcer appears to be increased in smokers and clamp, and the esophagus is occluded by placing tension on in patients who consume nonsteroidal anti-inflammatory the rubber drain surrounding it while the anesthetist injects a drugs (NSAIDs). We routinely discourage NSAID use after series of 10 ml aliquots of methylene blue dye through the GBP. Perforation of the proximal gastric pouch, probably nasogastric tube to determine whether the anastomosis is arising from perforation of a deep ulcer, has been seen with leaking. A total of 30 to 60 ml of methylene blue must usually administration of high-dose NSAIDs or with untreated ulcer be injected; lesser amounts will not stress the suture line diathesis. enough to constitute an adequate test. Alternatively, the Iron, vitamin B12, and folic acid deficiencies may occur anastomosis can be tested by performing intraoperative but can usually be corrected with oral supplementation52; gastroscopy. If leakage is present, the air insufflated during accordingly, GBP patients, like VBG and gastric banding the procedure will be visible bubbling from the leaking patients, should be advised to take a multivitamin daily for areas when the air-distended anastomosis is submerged in life. Compared with gastroplasty and gastric banding, GBP irrigation fluid. results in significantly lower serum hemoglobin and iron concentrations. This is primarily a problem in menstruating Troubleshooting When an intraoperative leak is identi- women. All menstruating women who have undergone GBP fied, the area of leakage should be oversewn with silk sutures should be treated prophylactically with supplemental oral until injection of additional methylene blue dye via the naso- ferrous sulfate, 325 mg/day. As many as six iron tablets a day gastric tube yields no further leakage. The most difficult area may be required if menstrual bleeding is heavy. Hormonal to repair is the posterior suture line, which is quite close to therapy to control or temporarily eliminate menses may be the gastric staple line. Posterior leaks are usually repaired by helpful. On occasion, intramuscular iron injections or, rarely, reinforcing the posterior suture line with additional sutures hysterectomy may be necessary. The risk of vitamin B12 between the excluded stomach and the jejunal limb; often, deficiency is higher after GBP than after gastroplasty or the entire posterior suture line is oversewn. In addition, a gastric banding, but this condition can be prevented with viable pedicle of omentum may be mobilized and placed supplemental oral vitamin B12, 500 mg/day. A few patients around the anastomosis for further reinforcement. Closed may require (or prefer) monthly B12 injections, which they suction drains may also be placed in this area, both to detect can learn to administer themselves. possible postoperative leakage and to control a postoperative Concerns have been expressed that GBP can lead to other leak or fistula. divalent cation deficiencies. Our group has not encountered Finally, a gastrostomy tube may be placed in the excluded zinc deficiencies 5 to 9 years after GBP, though we have portion of the stomach. This measure provides postoperative observed calcium deficiencies leading to osteoporosis, which decompression, which should prevent the development may take many years to become manifest and may not of undue tension on the Roux limb as a result of gastric be biochemically evident because of normal serum calcium distention. In addition, it establishes a route for enteral levels. It is therefore recommended that all GBP patients 05/08
  13. 13. © 2008 BC Decker Inc ACS Surgery: Principles and Practice 5 GI TRACT AND ABDOMEN 7 SURGICAL TREATMENT OF MORBID OBESITY — 13 take oral calcium supplements. Some may require vitamin D Laparoscopic Gastric Bypass supplementation. Magnesium deficiencies should be treated Laparoscopic GBP is currently the most popular bariatric with MgSO4 supplementation. procedure in the United States, both because of the rapid Although nutritional deficiencies do not appear to be a weight loss it achieves and because of the strong overall surgi- greater problem with long-limb GBP than with standard cal trend toward minimally invasive approaches. As noted [see proximal GBP, monitoring patients for possible malabsorp- Operative Planning, Laparoscopic versus Open Approach to tion of the fat-soluble vitamins A, D, and E after long-limb Bariatric Surgery, above], laparoscopic GBP achieves the GBP is advisable. same weight-loss results as open GBP but yields less pain, BPD may be associated with all of the complications seen reduced disability, and a shorter duration of hospitalization. after GBP. In addition, patients who undergo BPD may Physiologically, laparoscopic GBP results in less operative experience diarrhea, severe protein malnutrition (manifested trauma than open GBP, less impairment of pulmonary func- as hypoalbuminemia), and deficiencies of vitamins A (mani- tion, and a less pronounced stress response. In addition, the fested as severe night blindness), D (manifested as severe laparoscopic technique is associated with lower incidences of osteoporosis), and E.50 Hypoalbuminemia may respond to oral pancreatic enzymes but often must be treated with total major wound infections and incisional hernias. Accordingly, parenteral nutrition. In some patients, it may prove necessary we recommend laparoscopic GBP over any other bariatric to lengthen the absorptive intestinal tract from 50 cm to procedure. 200 cm. Laparoscopic GBP poses significant technical challenges, even for surgeons with advanced laparoscopic skills. Most   of the variations seen at different institutions are related to A series of 672 open proximal GBP procedures reported various techniques for creation of the gastrojejunal anastomo- a 1.2% incidence of anastomotic leakage with peritonitis, sis, with some groups using a circular stapler, others a linear a 4.4% incidence of severe wound infections (defined as stapler, and still others a handsewn technique. The anvil of infections serious enough to delay hospital discharge), an the circular stapler may be placed within the proximal gastric 11.4% incidence of minor wound infections and seromas pouch either by means of flexible upper GI endoscopy, (which were easily treated at home), a less than 1% incidence through an approach similar to the snare-and-wire technique of gastric staple line disruption with the use of three superim- used for placement of a percutaneous endoscopic gastros- posed applications of a 90 mm linear stapler, a 15% incidence tomy (PEG) tube [see 5:18 Gastrointestinal Endoscopy], or by of stomal stenosis, a 13% incidence of marginal ulcer, a means of a gastrotomy of the stomach before pouch creation 16.9% incidence of incisional hernia, and a 10% incidence for intra-abdominal anvil placement, followed by staple of cholecystitis necessitating cholecystectomy.47 Gallstones closure of the gastrotomy. Peroral placement of the stapler’s developed in 32% of the GBP patients who had a normal anvil can be problematic: even the small 21 mm anvil is hard intraoperative gallbladder sonogram within 6 months of to pass through the proximal esophagus in some patients. surgery, and sludge was observed in another 10%. In a mul- To facilitate esophageal passage, a “flip-top” anvil design has ticenter randomized, prospective trial, the incidence of been introduced. With this design, a 25 mm anvil can gener- gallstones within 6 months of GBP was reduced from 32% to ally be passed without undue difficulty, thereby lowering the 2% by giving patients ursodeoxycholic acid, 300 mg twice risk of postoperative stenosis. We routinely use the linear daily.56 Gallstone formation beyond 6 months is uncommon. stapling method to create the gastrojejunal anastomosis; it is The operative mortality in this series was less than 1%. easier than circular stapling in this setting, and there is no risk Patients with respiratory insufficiency of obesity had an oper- of esophageal trauma from anvil passage. ative mortality of 2.2%, whereas those without pulmonary dysfunction had an operative mortality of 0.4%.   Neither the data from this randomized, prospective trial Step 1: Initial Access and Trocar Placement nor the data from selective studies support the contention that VBG is safer than GBP. Although GBP includes one Initial access to the abdomen is obtained through a small more anastomosis than VBG, complications such as leaks and left subcostal incision. Gas is insufflated into the abdomen via peritonitis occur with both operations. A common criticism a Veress needle to a pressure of 15 mm Hg; on occasion, a of GBP is that it is difficult to evaluate the distal gastric pouch pressure of 18 to 20 mm Hg may be necessary. A dilating and duodenum after the operation. Such evaluation, how- 5 mm trocar is then placed in this location. Many surgeons ever, can be done in 75% of patients by means of retrograde use commercially available trocars that allow direct vision passage of an endoscope into the duodenum and the stomach through the scope during passage of a 12 mm trocar. We and in other patients by means of percutaneous distal disten- encourage preinsufflation of the abdominal cavity before such tion gastrography. Bleeding from either the distal gastric a device is employed so as to enhance identification of the pouch or a duodenal ulcer is rare. Gastric mucosal metaplasia peritoneal sac and avoid organ injury. Additional trocars of the bypassed portion of the stomach may occur in some are placed in specific locations [see Figure 13]. The liver is 5% of patients after retrograde endoscopy, a finding that has retracted with a metal Nathanson liver retraction device raised concerns regarding the risk of carcinoma arising at that anchored to the bed, which is inserted after a 5 mm sharp location. To date, however, although many thousands of trocar is used to develop a tract into the abdominal cavity these procedures have been performed over the past four in the subxiphoid position and removed. If the left lateral decades, few cases of cancer in the bypassed stomach have section of the liver is very large (as in patients with steatosis), been reported. additional liver retractors may be necessary. 05/08