Obesity Surgery, 2, 47-49

Weight Loss Comparison of Gastric Bypass and Silastic@ Ring Vertical Gastroplasty

Victoria Zimmerman, RD*; Christian T. Campos, MD; Henry Buchwald, MD, PhD, FACS

Departmenfs of Nutrition* and Surgery, University of Minnesofa, Minneapolis, MN, USA.

Thirty-five patients who had undergone primary bariatric surgery between 14 January 1988 and 18 September 1990 were selected for retrospective analysis based on the availability of 3-month and l-year (f3 months) follow-up visit records. Fourteen patients had undergone a Roux- en-Y gastric bypass (RGB), and 21 patients had under- gone a SIlastic@ ring vertical gastroplasty (SRVG). Weight loss, pre- and postoperative body mass index (BMI), and the postoperative incidence of dumping syndrome, ane- mia, and food intolerance were compared. At 1 year (f3 months), the average weight loss was 40 kg for the entire group. The RGB patients lost an average of 41.7 kg, while the SRVG patients lost an average of 39.4 kg (not signifi- cant). The average preoperative BMI was 48.4 kg/m’ for both the RGB and SRVG patients. The l-year post- operative BMI was 30.8 kg/m* for the RGB patients and 32.4 kg/m* for the SRVG patients (not significant). One RGB patient developed a dumping syndrome, and one RGB patient showed evidence of a nutritional anemia. Neither complication was incapacitating. The SRVG patients had far more difficulty in advancing the con- sistency and variety of their diet in the early postoperative period, with only 82% (13/21) of the SRVG patients de- monstrating an ability to tolerate a regular consistency diet at the end of 1 year. Seventy-six percent (18/21) of the SRVG patients reported occasional vomiting at 1 year, compared to only 7% (1114) of the RGB patients. This retrospective analysis documented comparable weight loss for the RGB and SRVG operations. A greater in- cidence of eating problems up to 1 year postoperatively was observed in patients following SRVG in comparison to RGB.

Key words: Gastric bypass, gastroplasty, obesity.

Presented at the Eighth Annual Meeting of the American Society for Bariatric Surgery, Dallas, Texas, 6 June 1991. Correspondence and reprint requests to: Victoria Zimmerman, Box 84, Nutrition Services, University of Minnesota Hospital and Clinics, Harvard Street at East River Road, Minneapblis. MN 55455, USA. Tel : 612-625-8446; fax: 612-625-3206.

0 1992 Rapid Communications of Oxford Ltd

Introduction

The two most frequently employed surgical proce- dures for the treatment of morbid obesity today are the Roux-en-Y gastric bypass (RGB) and the vertical banded gastroplasty (VBG).’ Reported weight loss for the RGB one year after operation has ranged from 39 to 47 kg.2,3 One-year weight loss following VBG has been reported to range from 32 to 40 kg.4*5 The consensus regarding these two bariatric surgical procedures has been that the weight loss following RGB may be slightly greater than the weight loss following VBG, but that this weight loss may have been achieved with an increased incidence of nutritional deficiencies.’ Both operations are currently performed at the University of Minnesota Hospital and Clinic for the management of morbid obesity. Thirty-five patient records were retrospectively evaluated for weight loss, pre- and postoperative body mass index (BMI), and the incidence of dumping syndrome, anemia, and food intolerance.

Materials and Methods

Thirty-five patients, who had undergone primary operations for the management of morbid obesity between 14 January 1988 and 46 September 1990 and having recorded follow-up visits at 3 months and I year (f3 months) postoperatively, were selected for retrospective analysis. This evaluation included 14 patients who had undergone a RGB and 21 patients who had undergone a Silastic@ ring vertical gastroplasty (SRVG). All operations were performed by the same surgeon (HB). Every effort was made to construct a 25-35 ml upper gastric pouch in both the RGB and the SRVG procedures. Pouch sizes were visually assessed. The gastrojejunostomy of the RGB

Obesity Surgery. 2. 19% 47

Zimmerman, Campos and Buchwald

was constructed on the greater curvature of the stomach with a 0.7-1.2 cm diameter. The RGB stomata were not externally reinforced. The SRVG was constructed using a no. 24 French Maloney dilator placed along the lesser curvature of the stomach prior to the firing of the notched TA-90 stapler. The dilator was left in place as a 44 mm Silastic@ ring was secured in position with a 210 Prolene@ suture. Care was taken to avoid compressing the Silastic@ ring or allowing it to move on the securing suture.

All patients received one preoperative and a minimum of three postoperative dietary counseling sessions. Written materials specific to each type of operation were given to each patient. The SRVG patients were counseled to follow a pureed consistency diet for I month following surgery to minimize vomiting.

Weight loss and BMI comparisons were made based on the actual weights recorded at the 1 year (f3 months) postoperative clinic visit. BMI was calculated as weight (kg)/height (m)‘. The data on dumping syndrome, anemia, and food intolerance were taken from the clinic visit chart notes and from the laboratory values recorded in the medical record. Means and standard deviations were calculated for the variables under review, and statistical significance was de- termined using a two-tailed Student’s f-test for continuous data and a chi-square test for categorical data. A p value less than 0.05 was considered indicative of statistical significance.

Table 2. Ability to tolerate solid foods

3 months post-op 1 year post-op

RGB 13114 (93%) 13114 (93%) SRVG 12/21 (57%) 13121 (62%)

RGB, Roux-en-Y gastric bypass; SRVG. Silastic@ ring vertical gastroplasty.

the RGB and the SRVG patients. The one-year mean postoperative BMI for the 14 RGB patients was 30.6 kg/m’, compared to a mean BMI of 32.6 kg/m2 in the 21 SRVG patients (Table 1). This difference was also not statistically significant.

Thirteen of the 14 RGB patients (93%) were able to tolerate solid foods at both 3 months and I year postoperatively. In comparison, only 12 of the 21 SRVG patients (57%) were able to tolerate solid foods at 3 months postoperatively. This increased to 13 of 21 (62%) by the end of the first year (Table 2).

Only two of the RGB patients (14%) reported any episodes of vomiting 3 months following surgery. This decreased to one patient (7%) by the end of the first year. Eighteen of the 21 SRVG patients (86%) reported at least occasional vomiting 3 months postoperatively. This only decreased to 16 of 21 patients (76%) by the end of the first year (p < 0.01 vs RGB) (Table 3).

Anemia was not documented in any of the SRVG patients. One case of iron deficiency anemia was recorded in a RGB patient. Dumping syndrome symptoms that were not readily managed by diet were reported by one of the RGB patients. These symptoms resolved completely by the one-year follow-up visit.

Discussion

Results

The one-year mean postoperative weight loss for the 35 patients was 40 kg (range: 20-93 kg). The 14 RGB patients had a mean weight loss of 41.7 f 12.6 kg; the 21 SRVG patients lost an average of 39.4 & 18.7 kg (Table 1). The difference in weight loss between the two groups was not statistically significant. The average postoperative BMI was 46.4 kg/m2 for both

In the University of Minnesota series, the RGB and SRVG operations were equally effective in achieving weight loss in the morbidly obese patient after one year. The preoperative BMIs were the same in the RGB and SRVG groups, indicating an equal magnitude of obesity in both groups. A BMI of 40 mg/m’ or greater is generally considered indicative of morbid Table 1. Weight loss and body mass index results

Weight loss BMI (kg/m*)

(kg) Preoperative Postoperative

RGB 41.7 + 12.6 46.4 + 7.3 30.6 f 5.0 SRVG 39.4 + 18.7 46.4 & 9.2 32.4 f 6.8

Results are presented as the mean & SD; all intergroup comparisons are not significant. RGB, Roux-en-Y gastric bypass; SVRG, Silastic ring vertical gastroplasty.

Table 3. Incidence of vomiting

3 months post-op 1 year post-op

RGB 2/14 (14%) l/14 (7%) SRVG 18121 (86%) 16/21 (76%)

RGB, Roux-en-Y gastric bypass; SRVG, Silasti@ ring vertical gastroplasty.

48 Obesity Slugery. 2, 1992

Weight Loss Comparison of Gastric Stapling Procedures

In conclusion, weight loss was comparable between the RGB and the SRVG patients in this limited, one-year, retrospective study. When selecting the appropriate bariatric operation for a morbidly obese patient, the risk of vomiting and food intolerance following SRVG must be weighed against the risk of dumping syndrome and anemia following RGB.

obesity. There was a slight difference in the one-year postoperative BMI values, but this did not achieve statistical significance.

The RGB patients reported minimal vomiting or problems with solid food intake, even in the early postoperative period. The main nutritional concern following RGB is the increased risk of anemia due to impaired iron or cyanocobalamin absorption.’ That only one patient in this series developed an anemia in the first year may not be representative of the true incidence of this problem, as iron deficiency anemia may take from 14 months to 7 years to develop’ and cyanocobalamin deficiency may take at least 2 years to become clinically apparent.6

The dumping syndrome has been reported in at least 50% of patients following RGB when these patients were ‘sweet eaters’.4 This problem can generally be managed by eliminating sweets from the diet and avoiding beverages at mealtimes. One RGB patient in this series reported dumping syndrome symptoms that were not responsive to the usual dietary measures. These symptoms were not debilitating and had resolved by the end of the first postoperative year.

The major complications following SRVG were poor tolerance of solid foods and occasional vomiting. Seventy-six percent of the SRVG patients continued to report at least occasional vomiting by the end of the first postoperative year. The majority of these patients become better able to manage solid foods after the first 3-6 months after surgery. Despite their inability to tolerate solid foods consistently, and the greater than 75% incidence of occasional vomiting, the SRVG patients were generally quite satisfied with the results of their operative procedure.

References

1. Hubbard VS, Hall WH. National Institutes of Health, Consensus Development Conference Statement on Gastrointestinal Surgery for Severe Obesity, 25-27 March 1991. Oh Surg 1991; 1: 25765.

2. Crowley LV, Seay J, Mullin G. Late effects of gastric bypass for obesity. Am] Gastroenferol 1984; 79: 850-60.

3. Thompson WR, Amaral JF, Caldwell MD, et al. Complications and weight loss in 150 consecutive gastric exclusion patients. Am ] Swg 1983; 146: 602-12.

4. Sugerman HJ, Starkey JV, Birkenhauer R. Randomized prospective trial of gastric bypass versus vertical banded gastroplasty for morbid obesity and their effects on sweets versus non-sweets eaters. Ann Swg 1987; 205: 613-24.

5. Makarewicz PA, Freeman JB, Burchett H, et al. Vertical banded gastroplasty: assessment of efficacy. Swgefy 1985; 98: 700-8.

6. Marcuard SP, Sinar DR, Swanson MS, et al. Absence of luminal intrinsic factor after gastric bypass surgery for morbid obesity. Dig Dis Sci 1989; 34: 1238-42.

(Received 20 ]uly 1991; accepted 5 October 1991)

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