GASTRIC BYPASS

Roye, G Dean

In the United States, fFrom 1980 to 1999 the percentage of obese people, defined as being greater than 30% of ideal body weight, increased from 15% to 27%.1 In Rhode Island 18% of adults are obese and 1.5% of these are classified as morbidly obese (class III obesity).2 Obesity is one of the risk factors for many other diseases, such as heart disease, sleep apnea, diabetes and hypertension. Obesity is defined in different ways; however, the Body Mass Index (BMI), calculated as weight in kilograms divided by the square of height in meters, gives physicians a measure of obesity across many different body types. While BMI does not account for muscle mass, people whose BMI is greater than 30 are defined as obese. Obesity can be further ranked in classes (I, II, III) based on increasing risk of developing medical problems.3 (Table 1)

GASTRIC BYPASS

Medical therapies, from diets to medication, are often the first line of treatment for obesity, yet for obesity refractory to these measures, surgery can be considered for the highly motivated patient. Surgery for weight loss, or bariatric surgery, has gone through many developments. Gastric stapling, the vertical banded gastroplasty, was for many years the standard bariatric operation. However, the gastric bypass, developed by Dr. Mason at the University of Iowa and first reported in 1967, is the current standard surgical approach. Initially devised as a gastric pouch with the bypass constructed as a loop gastrojejunostomy, it has been modified over the past 3 decades to the current Roux-en-Y technique. (Figures 1, 2)4 Trends in the operation have been to a smaller gastric pouch, a longer Roux limb and a vertical rather than a horizontal created gastric pouch.

While the innovations are generally accepted, several controversies as to technical aspect of the surgery exist. Debate exists over the need for division of the stomach during the gastric partitioning. Current techniques either divide the stomach and separate the pouch from the distal stomach or staple the stomach in continuity with at least 8 rows of staples to create a functional division of the stomach. Both methods are effective with gastro-gastric fistula rates and staple line disruption rates of 12%?6 A small percentage of patients may have dilation of the gastro-jejunal anastamosis and have subsequent weight regain. Fobi has advocated enforcement of the gastric outlet with a silastic ring (Fobi procedure) to reduce the possibility of late dilation of the gastric outlet and loss of restriction. However, there is no evidence that this reduces the incidence of recidivism and does have a 2-3% risk of erosion of the ring into the stomach.7

A recent innovation, that has been partially responsible for the current enthusiasm for bariatric surgery, is the laparoscopic approach, ors. Wittgrove and Clark reported the first laparoscopic gastric bypass in 1994.8 Since 1994, there have been numerous reports from different authors reporting their techniques and results for laparoscopic gastric bypass surgery. A current search of the National Library of Medicine (PubMed) revealed 171 articles related to laparoscopic gastric bypass. Large series have confirmed the efficacy and safety of the laparoscopic approach, but the technique is limited by the size of the patient and the presence of intraabdominal adhesions.9,10

PATIENT SELECTION

Patient selection for bariatric surgery has evolved from using the criteria of greater than 100 pounds over ideal weight based on the Metropolitan Life tables to criteria outlined by the 1991 NIH Consensus Development Panel.” Patients are candidates if:

1. BMI > or = 40 kg/m2 or BMI > or = 35 with two obesity related comorbid diseases and

2. Have failed of nonsurgical attempts at weight loss and

3. Have no endocrine disorders that cause massive obesity and

4. Psychologically stable

Patients also need to understand the operation, why it works and why it fails. Lastly, they need to commit to long-term post-operative follow up and have no alcohol or substance abuse problems.12

RESULTS

The gastric bypass produces durable long-term weight loss. Pories showed that the weight loss peaks at approximately 18 months with about 75% of excess bodyweight lost (EBW). Further follow up of this cohort demonstrated that patients had gained back some weight but still had lost 58% of EBW at an average of 5 years, and 55% loss of EBW at 10 years.12 From August 2000 to December 2002 the authors have performed 231 gastric bypass operations with patients having average weight loss of 64% of EBW at one year.

In addition to weight control the gastric bypass improves or cures multiple obesity related diseases. 99% of patients with impaired glucose tolerance have correction of insulin resistance and 83% of patients with diabetes mellitus type II (NIDDM) have the disease effectively controlled. Other benefits include an improvement or cure in patients with sleep apnea (90%), hypertension (43%), and dyslipidemias (>95).14 Gastro-esophageal reflux disease (GERD), venous stasis, and urinary stress incontinence, that are related to increased intra-abdominal pressure associated with obesity, are also improved. 89% of patients with GERD are off medications following surgery.14 Pulmonary hypertension related to obesity-hypoventilation syndrome is improved after surgery and cerebrospinal fluid pressure, felt to be related to development of pseudotumor cerebri, is also reduced with weight loss.16-19

COMPLICATIONS

Every medical treatment has complications and the gastric bypass is no exception. Monitoring of results and complications aids in quality assurance and improvement in patient care. Complications after gastric bypass surgery can be broken down into major (life threatening) and minor morbidity. Complications related to gastric bypass surgery are outlined in Table 2 and the authors’ results are compared with the current literature.12,20 (Table 2)

CONCLUSIONS

There are potentially 11,000 patients in Rhode Island who are candidates for gastric bypass surgery.2 Though die operation has risks, for many people, the gastric bypass represents the beginning of a thinner and healthier life. These obese patients, who have major comorbidities and significant surgical risks, have the most to gain with a successful bariatric procedure. Surgery may be their only chance for normal life expectancy.

REFERENCES

1. National Center for Chronic Disease Prevention and Health Promotion, www.cclc.gov/ nccdphp/dnpa/obesity/defining.htm. Accessed April 15,2003.

2. Buechner JS Med Health RI 2003:86:81-2.

3. Clinical Cuidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults-The Evidence Report. National Institutes of Health. Obes Res 1998; 6:23S-33S.

4. Mason E.E, Ito C. Surg Clin N Am 1967:47:1345-51.

5. BrolinR. Surg 1993;! 13:484-90.

6. MacLean L, Rhodes B, Sampalis J, et al. Am J Surg 1980; 140:750-4.

7. Fobi MA, Lee H, Holness R. et at WoM J Surg 1998:22:925-35.

8. Wittgrove AC, Clark CW, Schubert KR. Obes Surg 1996;6:500-4.

9. Schauer PR. Ikramuddin S, Gourash W, et al. Ann Surg2000;232:515-29.

10. Wittgrove AC, Clark CW. Obes Surg 2000:10:233-9.

11. NIH Conference: Gastrointestinal surgery for severe obesity. Consensus Development Conference Panel. Ann Intern Med 1991:115:95661.

12. Brolin R.: Castric bypass. Surg CIm N Am 81:1077-1095,2001.

13. Pories WJ, Swanson MS, MacDonald KG, et al. Arm Surg 1995:222:339-50; discussion 350-2.

14. Dhabuwala A, Cannan RJ, Stubbs RS. Obes Surg 2000:10:428-35.

15. Smith SC, Edwards CB, Goodman CN. Obes Surg 1997:7:479-84.

16. Sugerman HJ. Surg Clin North Am 2001:81:1063-75.

17. Sugerman H, Baron P, Fairman R. et al. Ann Surg 1988; 207:604-9.

18. Sugerman HJ, Felton WL 3rd, Salvam JB Jr, et al. Neural 1995; 45:1655-9.

19. Sugerman H, Windsor A, Bessos M, et al. J Intern Med 1997:241:71-9.

20. Byrne T. Surg Clin NAm 2001 ;81:1181 -93.

G. DEAN ROYE, MD, AND DAVID T. HARRINGTON, MD

G. Dean Roye, MD, is Assistant Professor of Surgery and Director of Bariatric Surgery, Brown Medical School.

DavidT. Harrington, MD, is Assistant Professor of Surgery and Associate Residency Program Director, Brown Medical School.

CORRESPONDENCE:

G. Dean Roye, MD

University Surgical Associates

2 Dudley St., Suite 470

Providence, RI 02905

Phone: (401) 553-8310

Fax: (401) 868-2301

e-mail: Groye@usasurg.org

Copyright Rhode Island Medical Society Feb 2004

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