obesity surgery: pros and cons
TRANSCRIPT
J. Endocrinol. Invest. 25: 925-928, 2002
OPINION
Obesity surgery: Pros and cons
J.A. Waitman*, and L.J. Aronne** *Memorial Sioan Kettering Cancer Center, New York, New York, **Weill Medical College of Cornell University, New York, New York, USA
INTRODUCTION
Overweight and obesity are reaching epidemic proportions throughout the world. Surgery is considered by many as the most effective therapy for obesity, a complex, multi-factorial disorder that has become a leading cause ofserious illness such as Type 2 diabetes, hypertension, hyperlipidemia, coronary artery disease, and sleep apnea. While abdominal surgery is clearly an intensive intervention, the burden that extreme obesity and its comorbidities place on patients and on society, coupled with our inability to treat it as effectively by less invasive methods, make obesity surgery an option to consider in eligible patients. Despite advancing research in the pharmacological management of obesity, surgery has consistently produced the greatest weight loss and best weight maintenance. The procedures that are currently in use include the Roux-en-Y Gastric Bypass (RYGB), Vertical Banded Gastroplasty (VBG), Laparoscopic Adjustable Silicone Gastric Band (LASGB), and Biliopancreatic Diversion with Duodenal Switch (BPDS). Criteria for the selection of patients for bariatric surgery have been developed by a Consensus Development Conference of the United States National Institutes of Health (NIH) in 1991 (1) and have been widely disseminated since. The 2 main criteria include a BMI ~40 or a BMI ~35 in a patient suffering from associated comorbidities. Another NIH panel (2) has recommended that for optimal care, a multi-disciplinary team, including a psychologist, dietitian, internist and the operating surgeon should evaluate all surgical candidates. The
©2002, Editrice Kurtis
Key-words: Obesity, surgery.
Correspondence: Prof. Louis J. Aronne, Weill Medical College of Carnell University. 1165 York Avenue. New York. NY 10021.
E-mail: [email protected]
Accepted September 2.2002.
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candidate must have a clear understanding of the risks and benefits associated with the procedure, as weil as realistic expectations of the weight loss that can be achieved. Patients should understand that the operation will impact the way that they eat and live, and recognize the need for long term medical follow-up and nutritional support (2, 3).
RYGB
The RYGB achieves weight loss through 2 separate mechanisms. A small gastric pouch prevents the patient from eating large quantities at a single sitting and a gastrojejunostomy produces a dumping syndrome if the patient ingests high carbohydrate foods. In the longest follow up of patients after RYGB, Pories showed 58%, 55%, and 49% loss of excess weight (defined as the patient's weight - patient's ideal bw) at 5, 10, and 14 yr post-operatively (4). As a result of its efficacy, RYGB has become the procedure of choice in the surgical management of obesity. Since Wittgrove et al. first performed the RYGB using minimally invasive techniques, laparoscopic RYGB has become increasingly common (5). Comparisons of laparoscopic and open RYGB demonstrate similar efficacy with either approach (6). RYGB has been associated with improvement in cardiorespiratory symptoms, Type 2 diabetes mellitus, pseudotumor cerebri, dyslipidemias, gastroesophageal reflux*, and overall quality of life (1-4, 7, 8). The overall mortality following RYGB is less than 1 %, and is further reduced in patients with a lower BMI, the leading cause being pulmonary embolism. Another early serious complication is an anastomotic leak (1 .5-5%) that can lead to peritonitis, abscess formation, and sepsis. Other early postoperative complications include wound infections (4%), marginal ulcers (5%), stomal stenosis (6.6%), small bowel obstruction (1-2%), splenic laceration (3%), gastrointestinal hemorrhage (1 %), intraabdominal hemorrhage (2.2%), atalectasis (12%), and wound dehiscence (8).
Fig. 1 - Malabsorptive bariatric procedures. (A) Jejunoileal bypass; (B) biliopancreatic diversion; (C) duodenal switch. From (3) with permission.
Schauer et al. reported that 9.8% of the post laparoscopic RYGB patients required surgical intervention after the initial operation (8). Several authors have reported that the laparoscopic RYGB has a significant learning curve, such that many of the post-operative complications become less frequent as the experience of the surgeon increases. The advent of laparoscopic techniques has decreased the incidence of hernias and wound infections, but increased the incidence of anastomotic strictures and leaks. The most common late complication following RYGB is the development of symptomatic gallstones. In a placebo-controlled trial, Sugerman demonstrated that the use of ursodiol in the 6 months postoperatively reduced the incidence of symptomatic gallstones from 32% to 2% (9). Stomal stenosis remains a frequent occurrence; Nguyen reported an incidence of 20% (6) . These stenoses can usually be managed through endoscopic dilatation. In a group of patients 13-15 yr post-RYGB surgery, 68.8% reported continued problems of vomiting and 42.7% of "plugging " (10). The recognized metabolic consequences of the bypass procedure include deficiencies of iron, calcium, thiamin, vitamins A. C. D, and B12 . WernickeKorsakoff syndrome, secondary to thiamin deficiency can cause irreversible neurologic damage if not recognized early. Sheu et al. demonstrated el-
Fig. 2 - Restrictive bariatric procedures. (A) VBG; (B) adjustable gastric banding; (C) Roux-en-Y GBP. From (3) with perm iss ion.
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Obesity surgery: Pros and cons
evated levels of homocysteine in the 6 months post-operatively (11) . These metabolic consequences of the RYGB necessitate the patient's cooperation with long-term medical follow-up, and a regimen of vitamin supplementation. It has been suggested that the RYGB is specifically suited to sweet eaters because dumping syndrome will result if patients attempt to eat soft, high caloric sweets which may pass through the pouch unimpeded. This provides an advantage in efficacy over pureIy restrictive procedures such as VBG and LASGB.
VERTICAL BANDED GASTROPLASTY
Mason, who first described gastroplasty for weight loss in 1971, also introduced the VBG in 1980 (12, 13). The VBG is a purely restrictive procedure. At present the technique involves partitioning the stomach and placing a 5-cm band around the lumen of the remaining portion of stomach. As is the ca se with RYGB, the VBG is routinely performed laparoscopically at this time. The RYGB has been shown to be more effective in achieving sustained weight loss than the VBG. Nightengale et al. showed that only 38% of VBG patients were able to sustain at least 50% of excess weight loss 3 years post-operatively (14) . An estimated 4-10% of patients who have VBG will not experience the expected post-operative weight loss. VBG does have relative benefits compared to other procedures, however. Because the VBG is exclusiveIya restrictive procedure, the malabsorptive complications associated with the RYGB are avoided, reducing the need for long-term follow-up. Furthermore, it is simpler to perform and is associated with fewer complications than RYGB. The overall mortality associated with the procedure is 0.5-1 %. The most common post-operative complications are atalectasis, pulmonary effusion, gastrointestinal leak, and stomal stenosis. Pulmonary embolism can also be seen in the immediate post-operative period. Staple line-dehiscence, given adequate surgical experience, is generally less than 10%. Patients are unable to eat large volumes at a single sitting . However, patients can ingest high caloric liquids without suffering any ill effects. It is for this reason that purely restrictive procedures are not recommended for patients who are partial to sweets.
LAPAROSCOPIC ADJUSTABLE SILICONE GASTRIC BANDING
LASGB has rapidly replaced VBG as the restrictive procedure of choice. An inflatable device that encircles the stomach is inserted laparoscopically.
IA. Waitman, and L.I Aronne
Adjustment of the stoma is readily accomplished by inflating the device with saline, via a subcutaneous port. It is less invasive than the VBG, because the stomach is not transected or stapled; in most instances, it can also be reversed laparoscopically, if necessary. This procedure carries less mortality risk and nutritional deficiencies are not common. However, failure to lose weight and esophageal dilatation are more common than with malabsorptive procedures. In addition, gastric erosion and obstruction, band leaks and slippage, and port infections are complications unique to this device. By far the most common of these late complications, which usually occurs within 12 months of surgery, is band slippage. The rate of this complication ranges from 9-40%. Most studies show that with increasing experience there is a decrease in the frequency ofthis complication. Approximately 13% of patients who have LASGB will require reoperation within the first post-operative year (15). Weight loss with LASGB is more gradual than with other techniques, because the band is not inflated until several weeks post-operatively. Results reported in the literature with this technique are mixed, and could reflect differences in patient selection, operating experience, or band inflation protocols. After 38-44 months, the average excess weight loss was 65% in one study (16). O'Brien et al. reported that the mean excess weight loss at 12, 24, 36, and 48 months were 51 %, 58.3%, 61.6%, and 68.2% respectively (17). Belachew et al. reported 80% of their patients lost 60% excess weight at 12 months (15). On the other hand, Kothari et al. reported only 19% excess weight loss following LASGB, with removal of 50% of bands for reasons including failure to lose weight, esophageal dilatation, and band leaks (18). Demaria et al. reported 50% of patients required LASGB removal within 42 months after surgery and only 11 % of patients achieved a BMI <35 and/or at least 50% reduction in excess weight without complications (19).
BILIOPANCREATIC DIVERSION WITH DUODENAL SWITCH
BPDS is the most complex procedure in widespread use for the treatment of obesity. This procedure is unique in that food intake is not restricted. The procedure carries a perioperative mortality rate of 0.5-2%. Marceau et al. showed that after an average follow-up time of 4.1 yr 81 % of patients who had a BPDS had a BM1<35, while only 6% had a BMI>40 (20).63% of patients reported a decreased appetite after the operation (20). Baltasar et al. found a mean fall in BMI of 37% in the obese and 43% in the su-
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per obese (21). Aside from weight loss there are additional benefits to this surgery. Improvements have been reported in blood glucose, cholesterol, cirrhosis, and blood pressure (22). The most common side-effects reported were malodorous stools and flatus, abdominal bloating, heartburn and abdominal pain, and diarrhea or more than 3 stools per day. 34% of patients reported that malodorous stools and flatus were a major problem. Metabolie derangements are also common, including lron deficiency (9%), hypocalcemia (8%), elevated PTH (17%), and Vitamin A deficiency (5%) (20). Protein deficiency is a major concern after this procedure. The yearly hospitalization rate for protein deficiency following BPDS is approximately 1 % (22). There have also been reports of liver failure and pancreatitis following the procedure. BPDS can now be performed laparoscopically in a 2-step procedure.
DISCUSSION
Surgical procedures for obesity are currently the most effective form of treatment available. Surgery is not a eure, however, and is associated with a number of short-term complications and long-term side-effects requiring vitamin supplementation and medical nutritional care. The need for re-operation and intervention is significant in the post-operative period. Nonetheless, the significant reduction in the risk of obesity-related comorbidities following surgery makes it an important form of management. At present, the most commonly performed procedure in the United States is the open and laparoscopic RYGB. Although insertion of the LASGB is easier to perform than RYGB and has fewer complications, less weight is lost and patients appear to have more drive to eat; longer-term data will be necessary to determine if the results achievable with this technique are lasting. The BPDS, while most effective and devoid of a restrictive component, also carries the greatest short and long-term complications and side effects. The decision to perform one procedure or another must consider many factors including the patient's weight, clinical status reliability, willingness to follow with the team for nutritional counseling, and eating pattern, as weil as the surgeon's experience and skill set.
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