**7. Weight loss procedure as a technique and selection of type of operation as a factor for weight regain after bariatric surgery**

The data review of different search engines about WR after well-known weight loss procedures worldwide is presented in **Table 2**. The data represent current estimated success of those procedures on a long-term follow-up. However, they do not represent the spread of different procedures and their popularity around the globe.

Sleeve Gastrectomy is the most common weight loss procedure all over the world so far. Its prevalence in United States and parts of Asia can be explained with eating habits or preferences of the patients there. For example, India's population is more than 50% vegetarian. Malabsorptive procedures such as Roux en Y or one anastomosis Gastric bypass have significant side effects on vegetarian patients and they struggle to compensate their protein and nutrient balance. So, the practice and experience reversed the type of weight loss procedures to Sleeve Gastrectomy (SLG) there. The growing number of weight loss operations all over the world, according to IFSO survey in 2016 total number of procedure, was 700,000 [46], provide enormous data about Bariatric procedures and patients. However, weight regain after bariatric surgery is one of the related topics with a relatively limited number of publications [47]. Long-term results of bariatric patient series reveal that after 2 years postoperatively, patients' rate of losing weight tends to decelerate [48]. Despite those results, Sleeve Gastrectomy is still the preferable operation for weight loss for patients and surgeons around the world. The numbers of Sleeve procedures are significantly higher than bypass procedures, according to data from IFSO Register and explanations of that status are not associated with long-term outcome


#### **Table 2.**

*Weight regain due to type of weight loss procedure: (electronic database data, including PubMed, MEDLINE, Embase, CINAHL, Web of Science and Scopus).*

and probability for WR [22]. Long-term results have shown that Sleeve Gastrectomy procedure is associated with significant WR within 10 years after surgery. The other main problem with that weight loss procedure is about development of a restrictive eating pattern and intractable gastroesophageal reflux, requiring revisional surgery in up to 20% of patients after primary procedure. The aspects of weight regain after SLG have been discussed in several publications; however, there are no systematic reviews, encompassing all surgical issues about the procedure. Anatomical/ surgical factors of weight regain after LSG are identified as: an initial large sleeve, incompletely resected fundus, and a large remnant antrum. We think there are three other issues about WR after Sleeve Gastrectomy as a technique and patient selection: Medical tourism as a factor for spread of the procedure**,** applicable to different Body Mass Index, even in super Obese patients as a first-stage procedure**,** the growing number of weight loss procedures performed privately, rather than in public Hospitals. The use of different bougies or dissection of the stomach to 2 or 4 cm above the pylorus has been investigated, and there are no standards about impact of that on weight regain. Several studies have showed no difference in dissection of the antrum as a predicting factor for weight regain after SLG. The learning curve of the surgeon and dissection around the short gastric vessels and left crura are also factors contributing to WR after LSG, according to different studies [2, 4, 5, 7, 8, 49, 50]. Medical tourism and offer of the SLG in private are another contributing factor for WR. Interestingly, there is a growing amount of data for patients, admitted to UK NHS hospitals in emergency after SLG abroad. One such example is about a case of our practice: a 45-year-old lady, who had a SLG in Turkey. She has developed bleeding from staple line, she has been transfused with 2 Units of blood there and sent home back on a commercial flight. The lady has been admitted from Airport to our Hospital with a HB of 89.0 g/l and urgent CT scan showed a big hematoma around the greater curvature of the stomach and spleen. Her management has been conservative, and outcome has been uneventful. However, she has been followed

#### *Predicting Factors for Weight Regain after Bariatric Surgery DOI: http://dx.doi.org/10.5772/intechopen.108715*

for 6 months only after surgery and her BMI at time of admission was 52.0. There are several other reports for admission of patients 1–2 weeks after SLG abroad, due to severe nausea, vomiting, or even dehydration and motility problems. It is known that about 15% of population in the United Kingdom has motility disorders of the esophagus. As we mentioned above, those disorders plus reflux after SLG are important factors for WR in those patients. The robust pre-operative investigations of bariatric patients and selection of the appropriate type of weight loss procedure are the key for long-term good results and prevention of substantial WR. Unfortunately, the economy recession and restrictions of funding about weight loss surgery are a serious concern about the increase of Bariatric procedures in NHS and the right of more Morbid Obese patients to have a proper selection and access to weight loss surgery. The other main issue is that in some parts of the United Kingdom, the only offered bariatric surgery in NHS is the Sleeve Gastrectomy. The patients with BMI over 50.0 are struggling to get an access for a bypass procedure, funded by NHS, in another Bariatric Center due to administrative problems. Weight regain after Roux en Y or one anastomosis Gastric bypass is also reported and documented. The WR after those two procedures is less than SLG, and the main reasons are associated with the volume and shape of the Gastric pouch, the diameter of gastro-jejunal anastomosis, and the length of biliary limb. The Surgeon, who first proposed mini-gastric bypass–Rutledge, describes his vision that dumping, as outcome of the procedure, contributes significantly to weight loss after surgery. Unfortunately, the motility of esophagus as a factor for WR after mini or one anastomosis gastric bypass is not investigated robustly so far. The quick transit of food from esophagus to stomach can accelerate appearance of eating disorders and minimize the effect of restriction. Most of the experts in bariatric surgery recommend the pouch-jejunal anastomosis not to be created immediately under esophago-gastric junction as the pouch will not be functioning optimally in terms of weight loss and long results can be disappointing. They also recommend the anastomosis between the pouch and jejunum to be on the side of the greater curvature and a length of 2–4 cm of the lesser curve of the stomach to be incorporated in the pouch.

It is known that Poiseuille's Law in physics postulates that the flow rate through a tube is inversely proportional to its length. Slow flow or emptying of the pouch is desirable after gastric bypass and contributes to the restriction [45, 51]. According to that law seems that the shape (length and diameter) may be rather more important than the size itself [52]. Another law in physics, known as LaPlace Law, postulates that the pressure required to distend a structure (tube) is inversely proportional to its radius. Interestingly, those two laws in physics have their application in creation of gastric pouch during bypass surgery. The shape and form of the pouch plus diameter of anastomosis with jejunum are mandatory for the optimal function of the gastric bypass. Literature review has confirmed that longer and narrower gastric pouch has a less dilatation in time after gastric bypass surgery. It combines slower emptying of the pouch, less probability for dumping syndrome, and less stretching 2 years after surgery. The Fobi Pouch Gastric bypass is an example for such a gastric pouch; however, evidence of long-term results is necessary to completely implement the postulate of the mentioned above physics law in Bariatric surgical practice [50]. WR, which is seen 3–5 years following laparoscopic gastric bypass surgery, is often explained because of enlargement of the pouch [22]. For durable restriction and therefore weight loss, a long narrow pouch is recommended. The length of pouch after one anastomosis gastric bypass (OAGB) is important about bile reflux and its complication also can contribute to WR.

There are still many debates about postoperative bile reflux after mini or one anastomosis gastric bypass and its significance about quality of life of patients and WR. The accepted standard in the technique is length of the sleeve—more than 16 cm. However, there are also different "tips" for avoiding the bile reflux and hence weight regain 5 years after the procedure. There are no statistically significant data to confirm the importance of the proposed "tips." The BMI over 50.0 kg/m2 before surgery, age of the patient at time of surgery, concurrent eating and metabolic disorders, length of the biliary limb, and diameter of the anastomosis are probably the predicting factors for outcome and WR after gastric bypass surgery [51, 53]. Innovations and suggestions as Fundo-Ring OAGB, wherein one anastomosis gastric bypass the proximal part of the pouch is wrapped with a fundus of the excluded part of the stomach to treat bile reflux and WR, are promising and interesting. However, long-term results are needed. The banding of Gastric pouch or the Gastric Sleeve with Fobi ring is another promising technique for surgical management of weight regain, and the long-term results will reveal more detailed information about feasibility and effectiveness of that proposed technique. The size of gastro-jejunal anastomosis is another important factor for WR. The recommendations are about a diameter of the anastomosis of 1.5–2.0 cm. Unfortunately, such diameter of anastomosis is a significant problem in the United Kingdom, whereas patients have esophageal dysmotility problems and their eating habits are different of those in patients from Europe and Middle East. Due to prevention of early complications with stricture and vomiting after Roux en Y Gastric bypass surgery, most Bariatric Centers in the United Kingdom prefer to do a stapled gastro-jejunal anastomosis with 45 mm reload. The short-term results and outcome of those patients are excellent; however, about 40% of them have a risk to develop significant WR 3–5 years after surgery. Unfortunately, the International Bariatric Registers are not giving adequate and exact information about the association between WR and the diameter of Gastro-jejunal anastomosis. Endoscopic management of the gastro-jejunal anastomosis as a size is effective and safe option in experienced hands as a first step for management of WR after Roux en Y Gastric bypass [54]. It allows several attempts in first instance to treat wide anastomosis or even peptic ulcers and is highly recommended opposite revisional surgery for management of WR in high-volume centers [51].

The length of biliary-pancreatic limb (BPL) has been the subject of several investigations about its effect on weight loss and hence WR after Gastric bypass surgery. The distalization of the biliopancreatic limb is associated with greater weight loss even in revisional surgery. The suggestion is based on data that patients with short biliary limb—between 50 and 60 cm, achieve less weight loss and regain a higher percentage of EXL within 5 years after surgery [14, 35]. However, the lessons of human anatomy should not be forgotten. The length of a small bowel in a human body is proportional to his height. The longer biliary limb in a bariatric patient postulates measurement of total small bowel length or at least of the common channel in order to avoid serious postoperative complications such as protein malnutrition and diarrhea [40, 55]. A study from the USA describes a racial difference in patients with distal biliary limb. According to Khattab et al. [34], patients with Afro-American and Asian origin do not tolerate the distal gastric bypass as well as white patients. There are other authors, who have several arguments toward the significance of the biliary limb length [35]. They think that reduction of common channel length should be tailored individually and there are other concomitant factors, which are responsible for weight loss and WR in every patient [35]. That factor, plus discrepancies in small bowel measurement during surgery, can play a significant role in mechanisms of weight regain after B/M Surgery.

#### *Predicting Factors for Weight Regain after Bariatric Surgery DOI: http://dx.doi.org/10.5772/intechopen.108715*

Several experimental studies have tried to interpret the presence of undiluted bile acids in the distal small bowel. They suggest that there are specific receptors, which are triggered by undiluted bile acids in the L cells in ileum, and those cells are responsible for enhanced release of GLP-1 and PYY hormones in the small bowel. Their theory explains why serum bile acid concentration is after Roux en Y Gastric bypass and that can lead to increased energy expenditure [17, 51]. Modern theories about better weight loss after malabsorptive procedures are based on hormonal mechanisms and interactions, which at the end achieve lower HbA1C levels, found among the group with longer biliary limb. Therefore, nutritional disturbances are more pronounced, and the diarrhea score significantly increased in the longer BPL group due to eating habits of the patient [24]. It is likely that these side effects will be observed in future reports on the patients with a longer BPL. So, the BPL length as a factor for WR is still in debate, and more randomized and long-term studies are required to obtain medical-based evidence for importance and influence of BPL over WR after Roux en Y Gastric bypass or one anastomosis bypass surgery. The length of BPL is in direct correlation with BMI of the patient nowadays. The standard length of BPL is 100 cm in length in patients with BMI between 40.0 and 48.0. When BMI is more than 48.0 and height of the patient is over 170 cm, BPL length is recommended to be 120–150 cm in length and the patient to have a common channel at least of 250 cm to avoid severe malnutrition, diarrhea, and vitamin deficiency.

Bariatric/Metabolic procedures, proposed for management of WR as SADI-S procedure, biliopancreatic diversion, and duodenal switch have been well investigated and documented, and their routine use has been largely abandoned due to abovementioned possibilities for complications and nutritional problems. Those patients need very close review and support by specialized Clinics and Hospitals for management of such nutritional and malabsorptive issues more than 2 years after primary procedure. However, the data of medical-based evidence and Guidelines of Bariatric Surgical Societies around the world are in a discrepancy about follow-up of patients after weight loss surgery. Data suggest that all B/MS patients to be reviewed and followed almost 5 years after surgery, but Guidelines recommend a cutoff up to 2 years after primary procedures, leaving a significant and not relevant burden of follow-up to General Practitioners.
