COMPARISON OF WEIGHT LOSS, FOOD CONSUMPTION AND FREQUENCY OF VOMITINGAMONG ROUX-EN-Y GASTRIC BYPASS PATIENTS WITH OR WITHOUT CONSTRICTIONRING

INTRODUCTION

Obesity is often accompanied by various co-morbidities and poor quality of life.Bariatric surgery is the only treatment that promotes successful weight loss andlong-term maintenance of weight loss²⁶. However, the standard of success after bariatric surgery is, besidesexcess weight loss, control of co-morbidities arising from obesity as well asimprovement in the quality of life of patients¹.

However, the debate continues over what and how would be the best procedure to befollowed^1-3. Currently the most frequently performed procedure isRoux-en-Y gastric bypass (RYGBP), which combines gastric restriction with intestinalmalabsorption and causing significant weight loss and long-term maintenance ofweight²⁶. As part of thisprocedure, the pylorus is not included in the new gastric pouch. Accordingly, Fobi etal^14-16 initiated description of alternative methods to prevent rapidgastric emptying, alleviate dumping syndrome, alleviate and avoid weight regain due tothe possible dilatation of the gastro-jejunal anastomosis³. Such methods include placing a ring around the gastricpouch, giving rise to the so-called "banded" RYGBP.

However, some studies have shown decreased quality of life due to the reduced diameterthat some rings can cause at the base of the gastric pouch provoking frequentvomiting¹ and intolerance tosome foods⁷ without showingsignificant differences in weight loss nor in resolution of co-morbidades². Some patients require the removal of thering years after surgery, with immediate resolution of symptoms²⁴. There is still no consensus on the needof placing a ring during RYGBP²³ andstudies monitoring the results with and without the placement of the ring are few andfar between³.

Thus, the aim of this study was to compare weight loss, consumption of macronutrients(carbohydrates, protein and lipids) and frequency of vomiting among patients whounderwent RYGBP with and without the placement of the constrictive ring around thegastric pouch.

METHODS

This was a retrospective study in which medical records from the Gastrocirurgia Clinicof Brasília, in Brasília, DF, Brazil, were analyzed. The objective was tocompare data from two different groups of patients: those who underwent RYGBP with theplacement of the constrictive ring around the gastric pouch (group with a ring) andthose who underwent the same procedure without placement of the ring (group without aring). Inclusion criteria were: availability of data on weight, food consumption andprevalence of vomiting during a period of one year or more after surgery; and havingbeen operated on by the same surgical team. The standard ring used was one of silicone,6.9 cm in length.

Food consumption data were collected using three random 24-hour recalls registeredduring postoperative nutritional care sessions at the end of the first year after theoperation. The Diet Win® program was used to calculate these data. The time sinceoperation was considered that relative to the last nutritional consultation. Data onpercentage of excess weight loss and the occurrence of vomiting were collected using theweight and the registers of this same session. Excess weight loss was calculated basedon ideal body weight as established by tables produced by the Metropolitan LifeInsurance Co, USA¹⁹.

The register of the occurrence of vomiting was ​​based on the following parametersaccording to the frequency of the individual patient: never, rarely, occasional,monthly, once weekly, twice or more times per week. Accordingly, for purposes ofanalysis, the frequency was divided into: never, rarely, occasionally and frequently.Thus, the term "frequently" included patients who reported vomiting monthly, weekly andtwice or more times per week.

To compare the mean values ​​of variables between the groups with and without a ring,Student t tests and the nonparametric Mann-Whitney tests were used. To compare thefrequency of vomiting between groups, the chi-square test was used.

RESULTS

There were 60 patients included in this study, 30 in the group with a ring (men: 20%,women: 80%) and 30 in the group without a ring (men: 13%, women: 87%). The mean timesince operation for the group with a ring was 87.83±17.50 months, and for thegroup without a ring, 50.69±15.29 months. Excess weight loss did not differbetween groups. The consumption of protein (g), protein/kg of body weight, % of proteinrelative to the total energy value and fibers (g) was higher in the group without a ring(p=0.028; p=0.025; p<0.01 and p˂0.01, respectively). Fat intake (g) and % of lipidsin relation to total energy intake was higher in the group with a ring (p=0.01 andp˂0.01, respectively) (Table 1).

The frequency of vomiting differed significantly between the groups (p˂0.01) since thepercentage of patients who never reported the occurrence was statistically higher in thegroup without a ring (80%vs46%). The percentage who reported frequent occurrence wasstatistically higher in the group with a ring (25%vs0%) (Table 2).

DISCUSSION

One factor that optimizes the effects of satiety after RYGBP is the constriction made​​in the distal part of the gastric pouch, which causes a delay in gastric emptying andconsequent decrease in food intake. One of the ways that some surgeons achieve this goalis by placing a ring around the gastric pouch^5,14. Fobi et al.^14,15,16 pioneered the use ofconstrictive rings in gastric bypass procedures, placing them near the gastro-jejunalanastomosis.

In this study, no difference in weight loss between patients operated with and withoutthe placement of the ring was found. A similar result was observed by Arceo-olaiz et al(2008)², in a study of 60 RYGBPpatients with and without a constrictive ring of 6.5 cm in length, made ofpolypropylene. In this study, excess weight loss did not differ between the groups after6,12 and 24 months postoperatively.

These results lead to reflection on other factors that influence postoperative weightloss. Eating habits^9,10, physical activity and changes in hormone and energymetabolism resulting from the operação^11,12, for example, seem tobe great predictors of postoperative weight loss. Furthermore, the inclusion of amultidisciplinary team approach in bariatric surgery programs has improved weight lossand patient adherence to treatment, regardless of the presence of a constrictive ring.Besides this, ethnic and cultural characteristics may play a role in the success ofsurgery².

Awad (2012) et al³ studied weight lossand quality of life of patients with and without a constrictive ring, 6.5 cm in lengthmade of polypropylene. Excess weight loss up to 24 months postoperatively did not differbetween the groups, but from 36 months to ten years after their operation, the groupwith a ring showed significantly greater weight loss. Despite this, excess weight lossin the group without a ring continued, from 36 months postoperative, at around 60%,which is still considered to be a successful postoperative outcome, showing long-termweight loss maintenance even without placing a ring.

Stubbs et al. (2006)²³ believe thatthe decision on the use of a ring is essentially based on the balance between the weightloss maintenance and quality of diet. In the study by Awad et al (2012)³ the group with a ring had greaterdifficulty in eating. It is known that the quality and variety of food decreases inproportion to the length of the ring²⁵. In this study, similar results could be seen as in the case of proteinand fiber consumption which was significantly lower, with significantly higherconsumption of lipids in the group with a ring. Stubbs et al. (2006)²³ observed that, indeed, meat consumptionbecomes less frequent as the ring length is decreased.

It is known that the quality of food has great influence on the quality of weight lossafter RYGBP^9,10. The study by Awad et al (2012)³, despite having observed long-term parameters and havingfound greater weight loss in patients with a ring, did not measure body composition inorder to assess whether such weight loss was predominantly in the form fat, as isdesired.

In this study, it was observed that the group with a ring had a average protein intake(in grams) below the lower recommended limit for bariatric patients (60 g)¹⁷. An inadequate protein intake canprovoke greater loss of lean mass and still deprive the patient of a number of nutrientsessential to health¹³. Thus, onecannot conclude as being positive the greater weight loss observed in the study groupwith a ring in the study of Awad et al. (2012)³ base exclusively on data presented in the study. In order toconclude that such weight loss was of good quality and that the patient's health waspreserved, biochemical parameters and body composition should have been analyzed.

Fobi et al (1998)¹⁴ supported placingthe constrictive ring around the gastric pouch, arguing that it is able to containfuture expansion of a sutured stoma, which could result in increased volume of foodintake and resultant weight regain if it were to be greater than 18 mm. However, weightregain seems to have varied causes that go beyond a patient's simple ability to eatlarger volumes. One possible cause, as shown by the authors of the present study in2009, is the lower energy expenditure that such patients may present¹¹, and furthermore, specific eatinghabits, such as excessive consumption of caloric liquids, especially alcoholic beveragesand the development of binge eating habits¹⁰ which can also impair weight loss after RYGBP.

The placement of a ring in order to maintain the size of the gastric pouch is still usedby some surgeons in weight loss operations. Polypropylene, double knit, heavy sutures,Silastic®, Dacron® and Gore-Tex® are some of the materialsutilized^5,14; however, none has been shown to immune tocomplications. Tadeucci et al. (2008)²⁵ believe that complications associated with a ring may outweigh itsbenefit. Complications such as band erosion, nausea, vomiting, malnutrition anddysphagia for solids and liquids can occur²⁴. Thus, most RYGBP surgeons now opt not to use a ring²².

Although it can occur, the development of vomiting after RYGBP is not common². Nevertheless, it can reach a frequencyof 68.8%^7,14. Most causes of vomiting due to stenosis of theanastomosis¹⁵ that can occurdepending on the placement of the ring.

Since the ring showed no indication of having caused any difference in weight loss inthis study, the group of patients with a ring showed significantly higher levels offrequent vomiting. Some other studies have reported the occurrence of vomiting relatedto a constrictive ring^1,2. This study finds that one fourth of thepatients with a ring reported the occurrence of vomiting as being frequent. Reports ofits frequency show happen monthly, once/twice a week or even more. Arasaki etal.(2005)¹ consider chronic"vomiters" after bariatric surgery as those vomiting more than ten times a month. Othersconsider that the classification should be given to those who vomit more than threetimes per week². Thus, not allpatients who reported their vomiting as being frequent in this study can be consideredchronic. Unfortunately, there are no data available here on the nutritional status ofthese patients. However, it is known that a register of "frequent" is importantinformation, since vomit have serious concern when it become chronic provokingmalnutrition⁸.

Another factor to consider is the length of the ring to be placed. The high prevalenceof vomiting observed as a function of the ring is due to the reduced flow of food itcauses. Arasaki et al. (2005)¹compared two groups of RYGBP patients: one of patients who received a ring 6.2 cm inlength and another with 7.7 cm which allowed 100% flow of food through the gastricoutlet. The chance of becoming chronic regurgitants was 4.5 times greater in the groupwith the shorter length than the other. Significant higher prevalence of chronicvomiting was seen among shorter rings (23%vs8%). The same was observed by Stubbs et al.(2006)²³, wherein the frequencyof regurgitation was also higher in patients with 5.5 cm ring, compared with those of6.5 cm. These results show that excessive restriction of output of the gastric pouch canworsen the quality of life of patients and, without proper treatment, may increasechances of nutritional risk, which in turn, may lead to other serious complications,such as acute neuropathy⁶.

The initial recommendation of Fobi et al.^14-16 was to place ring of5.5 cm long. However, this size provoked a high removal rate (20% of patients), whichmade ​​him to change his recommendation for larger ring length, 6-6.5 cm incircumference. The ring size used in this study was even higher - 6.9 cm long - but thisdid not prevent the onset of complications, such as vomiting and food intakedifficulties for the group with ring.

Treatment for vomiting after bariatric surgery usually consists of nutritionalre-education, use of prokinetics and psychological support. In failure, the symptoms areinterrupted only by removing the ring^1,7,14,25. Laparoscopic removal is feasible andsafe, with immediate and complete resolution of symptoms, and rapid recovery^24,25. In addition, laparoscopic surgery placing constrictive ring is moreexpensive, since it represents a longer procedure with higher cost, worsening even morethe cost-benefit of placing a ring during RYGBP.

This study has some limitations. Some authors suggest other hypotheses to explain theoccurrence of vomiting after RYGBP; among them, the hypotony of the lower esophagealsphincter¹, psychiatricdiseases²¹, nutritionaldisabilities¹⁸, ingestion oflarge volumes of food⁴, insufficientchewing and drinking fluids during meals^5,20. These parameters werenot examined in this study and may act as results confounders. Thus, medium and morelong-term data, collected under better controlled conditions, comparing patients weightloss, body composition and other parameters that assess their health and quality of lifewith and without ring, are needed to draw meaningful conclusions in this regard.

CONCLUSION

The placement of a constrictive ring during RYGBP does not offer advantages in weightloss and provokes lower consumption of protein and fibers with a higher incidence ofvomiting. These factors negatively influence the quality of weight loss, the quality oflife and the maintenance of health of the bariatric patient.