In 2017, researchers in Australia published the first data from a study that is comparing sleeve gastrectomy vs sleeve gastrectomy with a MiniMizer Ring (Bariatric Solutions) in 400 obese patients. Bariatric News talked to the lead investigator, Dr Chris Couch from the Perth Obesity Surgery clinic, about the causes of weight regain after surgery and the aims of the study.
“The body’s homeostatic mechanisms favour increased eating in order to regain weight after weight loss. Almost all bariatric procedures fail to some degree over time, due to this built-in homeostasis.”, he began. “This increased eating can in turn stretch any pouch or sleeve created by bariatric surgery. The laws of physics also come into play here, specifically La Place’s law which states: “The larger the vessel radius, the larger the wall tension required to withstand a given internal fluid pressure.” It is more difficult to stretch a narrow cylinder than a wider cylinder. In this case, as the pouch or sleeve enlarges, the stretching becomes easier.”
He explained that one solution is to prevent the initial stretching of the stomach. Placing a Ring during a sleeve gastrectomy could be advantageous in helping to prevent post-operative weight regain. However, he added that the case for placing a Ring in conjunction with a sleeve gastrectomy in order to prevent weight regain is still to be proven.
“Placing the MiniMizer Ring restricts the diameter to a set measurement, at the point of placement. For example, currently I am using the widest (8cm) setting, limiting the lumen size, at that point, to about a finger width. This impedes the natural process of stretching at that site. This restriction has the added benefit of making the patient aware when they are over eating by creating a sensation of fullness or discomfort. Of course, it does not mean that the sleeve cannot stretch above the Ring if the patient is persistent and forces food down. In short, the Ring may reduce the chance of the sleeve stretching by encouraging smaller meal sizes over the long term, due to the fixed diameter at the level of the Ring.”
Despite the possible advantages that the Ring may bring, there are some patients he might advise against receiving a Ring. Such patients are those who present with thickened or scarred tissue in the placement zone, as this may make placement difficult and possibly unsafe. Patients who present with scarred tissue in this region are commonly undergoing a revisional procedure following a gastric band and in this situation, he claims that the scar tissue might be advantageous as it could carry out a similar role as the Ring. In such cases where the scar tissue is particularly thick, he is reluctant to place a Ring.
He added that some patients who have undergone previous bariatric surgery involving stapling or those who have significant anatomical distortion, may be precluded from having a sleeve gastrectomy with or without a Ring, as might also be the case with patients who present with severe gastro-oesophageal reflux disease (GERD).
Dr Couch has performed over 450 ringed sleeves since September 2013. To date, he is aware that five or six of these Rings have been removed due to obstructive symptoms, sufficient to warrant their removal. He added that obstructive symptoms could result from the Ring being too tight, slipping or by it causing the sleeve to kink. With regards to erosion and device migration, he is not aware of any cases in his study group, although these issues are unlikely to be diagnosed unless they cause problems.
One of the questions the study is seeking to answer is, at what level below the oesophageal-gastric junction is the optimal site for the Ring. During the study, Dr Couch has used a range of difference positions (from 3.5cm to 6cm) below the oesophago-gastric junction. Once all the data is collected it is hoped it will reveal which position is the most effective and which causes the least problems and thereby give some indication about the optimal site for placement.
To assist with Ring placement, he added that it is sometimes beneficial to open the lesser omentum (Image 1), in order to view the advancing tip of the Ring as it is passed from the patient’s left to the right. During the procedure, he also uses landmarks on the Ligasure device as a measuring tool to assist with accurate placement of the Ring. He cautions against placing the ring if the surgeon is unable to place it in the desired position.
Minimizer ring on sleeve
“The study was designed to answer several questions. Firstly we are hoping to qualify and quantify any risks that might accompany placement of a MiniMizer Ring on a gastric sleeve. Secondly, we want to compare the long-term weight loss resulting from sleeve gastrectomy without the Ring with the long term weight loss resulting from sleeve gastrectomy with the Ring. We are comparing the post-surgery meal size between these two groups and also the impact, if any, the two procedures have on GERD symptoms and on the amount of post op regurgitation.” he explained.
It is hoped the study will also determine the optimal position below the oesophageal-gastric junction for placement of the MiniMizer Ring and the optimal diameter setting for the MiniMizer Ring. During the period of the study, different diameter settings were chosen, with the aim of creating a uniform gap size between the stomach and the Ring. The research team are also looking at whether repair of the oesophageal hiatus and whether the primary or revisional status of the surgery have any effect on the outcomes listed above. Patient satisfaction between the two groups is also being compared.
In total, 100 consecutive patients have undergone a sleeve gastrectomy without a Ring, followed by the next 300 consecutive patients who have undergone a sleeve gastrectomy with a MiniMizer Ring. All procedures were performed by Dr Couch and apart from the addition of the MiniMizer Ring in the last 300 patients, there were no changes made in the surgical technique for all 400 procedures. All procedures were performed using a 36 FG bougie in situ. Prior to the start of the trial, Dr Couch had completed 64 sleeve gastrectomies (learning curve) and by this time he had established his surgical technique.
To date, the initial results have shown no increase in the risk of post op leak or post op bleed when the Minimizer Ring was added to the sleeve gastrectomy. There were no deaths in either group. The leak rate was 1% in both groups. The post op bleed rate without the MiniMizer Ring was 1% and with the Ring was 0.7%. Overall, he said there appears to be no significant additional safety issues associated with use of the Ring in relation to the above criteria.
“We have up to 4.5 years of follow-up data on the first 100 patients who received a sleeve gastrectomy only and up to 3.5 years follow up on the patients who received a sleeve gastrectomy with the Ring. We are hopeful that there might be some trends identified in the 2-4 years post-procedure. For example, if a significant trend emerges with regards to better long term weight loss with the addition of the Minimizer Ring, then this would be an indicator that a ringed sleeve does bring with it a significant benefit.”
Outcomes from this study are available at: https://perthobesitysurgery.com.au/