DISCUSSION
The IGB treatment is a well-recognized therapy for overweight/obesity[2,3,12,13] and have been successfully used for weight loss for the last 20 years.[14] The mechanism of action of IGB is multifactorial and incompletely understood.[21,22] Theoretically IGB affects both the stretch receptors and the gastric capacity, increases satiety while decreasing the residual volume available for food, as well enlarging the gastric emptying time, and therefore could be considered a restrictive procedure to treat obesity.[15] Other proposed mechanism include changes in appetite-regulating hormones (decrease in ghrelin and leptin and increase in CCK concentrations); however there are conflicting reports. [21,22] The better results with IGB occur when the treatment is associated with behavioral changes.[2,3,12,13]
However, it is not possible to define the ideal balloon size for a specific patient, as the threshold for nausea, vomiting and/or abdominal pain are not measurable or predictable.[8]Moreover, a decrease in IGB efficacy in promoting weight loss due to a reduction of the satiety effect after three months has been demonstrated in some studies.[15-17]. However, the traditional IGB have some limitations: a decrease in the efficacy in promoting weight loss after 2 to 3 months , a maximum length of treatment is 6-month and a significant rate of complications during the early implantation period (nausea, vomiting, and discomfort), leading balloon extraction in 4–5% of patients.[5,12, 15-17] It is not possible to define the ideal balloon size for a specific patient, as the threshold for nausea, vomiting and/or abdominal pain are not measurable or predictable.[8] The introduction of the Spatz3® Adjustable Balloon system offers features that address these limitations.
The main complication was the early removal of the balloon (removal before nine months post implantation). However, most of these (n=12, 6.66%) were not due to adaptation symptoms, but for various other reasons, such as desire to give up the treatment, weight loss considered insufficient by the patient, and psychological intolerance (desire to eat, desire to remove the foreign device from the inside of the body). Only two removals (1.11%) were performed due to severe symptoms (excessive vomiting) in patients who did not wish to do the downward adjustment and decided to quit the treatment. The incidence of early removal in the present study was 7.77%, being similar to that observed in other studies conducted with Spatz, Machytka et al (2014)[6] observed 7.79% and Brooks et al (2014)[14] 5.47%. However, this rate is higher than the observed in studies conducted with conventional IGB, Genco et al (2005)[9] observed 0.44%, Lopez-Nava et al (2011)[12] 0.8% and Sallet et al (2004)[1] 3.4% . It is important to note that from the 14 early removals in this study, only 2 (1.24%) were due to early intolerance, approaching to the results previously described. Furthermore, patients who underwent downward adjustment (n = 8; 4.44%), all, without exception, completed the minimum 9 months treatment, similar to what was observed in other Spatz® IGB studies.[6,14] Thus, it seems that the downward balloon adjustment may contribute to a better adaptation and a lower early removal rate.
There were three cases (1.66%) of spontaneous deflation before nine months post implantation, the minimum time length established for treatment, with immediate replacement of the defective balloon and permanence in the treatment. This index is lower than the observed by Machytka et al (2011)[8] in Spatz® initial series (11.11%), but they used first and second generation Spatz® balloons, while in the present study we used only the third generation, that was described as having easier implantation and extraction procedures which are less complicated with fewer steps.[6] When compared with the study conducted by Brooks et al (2014)[14], that also used third generation Spatz® balloons, the spontaneous deflation index of the present study (1.66%) was lower (vs. 4.1%).
In one (0.55%) patient it was detected, at the tenth week of treatment, gas production inside the balloon, when the patient started to vomit again. An x-ray of the abdomen was performed, being observed air-fluid level inside the balloon. The balloon was then completely emptied and filled again with 3% sterile saline plus 10 mL of 4% methylene blue, the patient remained in the treatment without any problems and without the need for removal or replacement of the balloon. This complication has not been reported in any other Spatz® balloon study, and is believed to have happened, possibly, due to contamination of the liquid inside the balloon by anaerobic bacteria from the gastrointestinal tract.
There was one case (0.55%) of upper gastrointestinal bleeding without hemodynamic repercussions. At the endoscopy, was detected the presence of a tear in the gastroesophageal junction due to excess vomiting after an upward balloon adjustment. It was then removed half of the upward adjustment volume, with prompt improvement in symptoms and permanence in the treatment, with no need for balloon removal. Machytka et al (2014)[6] also showed one case (1.29%) of upper gastrointestinal bleeding, but due to gastric ulcer.
Regarding gastric ulcers, six (3.33%) were diagnosed in the gastric antrum lesser curvature. One of them (0.55%) needed the removal of the balloon due to intense pain and depth of the lesion. When asked, the patient said that was not taking the prescribed proton pump inhibitor (PPI). Five (2.77%) other ulcers were asymptomatic and were diagnosed during treatment (during an adjustment procedure) or at the removal of the balloon. All of them were treated conservatively with increasing PPI dose and sucralfate, with adequate response and wound healing. The incidence of ulcers is higher in studies using Spatz®balloons (Machytka et al (2014)[6]- 1.29% and Brooks et al (2014)[14] – 2.73%) than in studies using traditional balloons (Genco et al (2005)[2]– 0.2% and Sallet et al (2004)[1] – 0%). This can be possibly explained by the fact that the Spatz®balloon does not have a completely smooth surface, since it has a tail, which acts as a compression point on gastric mucosa[8], and could generate a pressure ulcer. There was in this study no case of gastric perforation, esophageal perforation or death.
Weight loss has traditionally been the main outcome measure of the efficacy of IGB treatment and was observed in the majority of our patients. The %EWL in the present study was similar or slightly superior than that observed in other Spatz® series reported in the literature (Table 5 ).
However the weight loss after the upward adjustment in the present study was lower than in other Spatz® studies (Table 5 ). This can be possibly attributed to the fact that in our study the upward adjustment was performed latter (7.12±1.63 months) than in the studies conducted by Machytka et al (2014)[6] and Brooks et al (2014)[14] , in which the mean adjustment time was 4.1 and 5.8 months, respectively, allowing more time for further weight loss. Or, more feasible, the upward adjustment is not effective in promoting extra weight loss.
In this study, the upward adjustment was done in all patients in the upward adjustment group. The incidence of this procedure (47.77%, n=86 of 180) was higher compared to Spatz® series of Genco et al (2013)[9] and Machytka (2014)[6], with 22.5% and 19.48% of upward adjustments, mainly by weight plateau. However, the percent of excess weight loss of patients that did the adjustment was not significantly higher when compared to those that did not. Similarly, Genco et al (2013)[9] reported that final mean BMI of the patients who did upward adjustment was higher than patients with Spatz® who did not, but there was no statistical significance and they highlighted that this observation was in a few number of patients and needed to be confirmed.
Considering our study model, the sample size is limited, but reasonable for a prospective study, and larger than other studies with this balloon. This study has limitations and the major one is the absence of a sham group, difficult to be done in a private center. However, in our opinion, the possibility to evaluate the real life tolerance, efficacy and complications associated with the use of Spatz3®IGB, and the presence of a control group (non adjustment group) compensate the absence of a sham group.
The long lasting treatment (one year) allows a longer nutritional counseling, in order to increase patient compliance and to reinforce the necessity of behavior changes from the very early stages of treatment. Patients should be aware that is important not only to lose weight, but to keep a sustained loss, as described by different authors.[18-20] Even with one year treatment, the majority of the patients still have obesity (final BMI 32.84kg/m² only four patients with BMI<25kg/m²). The Spatz3® use does not represent a definitive treatment to obesity and is necessary to be associated with permanent behavioral changes and probably a second balloon treatment. At this time, there is no contraindication to use the Spatz3® for a sequential therapy as traditional IGBs.[9]
Therefore, this study shows that Spatz3® IGB treatment is an effective procedure for weight reduction, without mortality but with higher morbidity rates when compared to tradition IGBs. Currently, the IGBs offer a safe and effective weight loss option for patients. It is cristal clear that the downward adjustment reduces the incidence of early removals due to intolerance. However, it is not clear if the upward adjustment is effective in promote extra weight loss, since all the analyzed parameters did not show statistical difference between both groups. On the other hand, the adjustment group showed a slightly higher treatment success rate. Additional clinical trials are necessary to better understand the difficulties and problems with Spatz3® IGB use, and the efficacy of the upward adjustment.