A safety study of laparoscopic single-anastomosis duodeno-ileal bypass with gastric plication (SADI-GP) in the management of morbid obesity

Background Bariatric surgery is more effective in the management of morbid obesity and related comorbidities than is conservative therapy. Pylorus-preserving single-anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-SG) is a modified duodenal switch technique. Gastric plication (GP) is an alternate to SG. Methods Morbidly obese (BMI of > 40, or > 35 in the presence of diabetes or prediabetes) patients were recruited and operated on to perform SADI with GP. Complications related to surgery were recorded to assess the feasibility of the procedure. Weight-loss outcomes were analysed to determine efficacy. Minnesota Multiphasic Personality Inventory 2 (MMPI-2) was recorded after 1 year of follow-up, and test scales were used to describe physiological phenomena. Results Seventeen middle-aged (mean: 40 years) patients were involved in our study; 15 of them were females. The mean duration of surgery was 205 min. There were no complications of conversion, death, bleeding, VTE or 30-day readmission to hospital. We did experience CD4a (pulmonary insufficiency due to chronic lung disease) and a CD3b (anastomosis leakage treated laparoscopically) complications. Vomiting occurred in three cases (CD1). Obesity-related comorbidities showed favourable resolution rates (77.8% for hypertension, 81.2% for dyslipidaemia, 100% for diabetes at the 1-year follow-up). Weight-loss outcomes were favourable (53.20 EWL%, and 35.58 TWL% at 1-year follow-up). Greater weight loss caused significantly higher levels of Depression (t(13.958) =  − 2.373; p = 0.00; p < 0.05) and Low Positive Emotions (t(13.301) =  − 2.954; p = 0.00; p < 0.05) and Introversion/Low Positive Emotionality (t(13.408) =  − 1.914; p = 0.02; p < 0.05) in MMPI-2 data. Conclusion According to our safety study, SADI-GP is a promising malabsorptive procedure, but a long-term high-volume case series or a randomised controlled trial is necessary to evaluate complication rates and weight-loss outcomes. Emotional dysregulation is common among bariatric surgery patients according to personality inventory data; therefore, psychological follow-up and psychotherapeutic support are necessary for weight-loss maintenance. Supplementary Information The online version contains supplementary material available at 10.1007/s00423-021-02276-9.

LGP combined with omega-loop duodenal switch was described by Karcz et al. [43]. An experimental model described the superiority of SADJ-GP over SG in terms of efficacy in the remission of T2DM [44]. Two prospective observational studies reporting outcomes of a combination of LGP and OAGB were identified during a literature search [45,46]. SADJ-SG and SADI-SG seem to have advantages over gastric bypass procedures (LRYGB and OAGB) because a more physiologic anastomosis (duodeno-jejunal or -ileal) is performed. Therefore, anastomotic ulcers deriving from afferent limb bile reflux through gastro-jejunal anastomosis should occur less frequently [27][28][29][30][31][32][33][34][35]. SG is the first part of these procedures which is very popular among bariatric surgeons due to its simplicity; however, it is only a restrictive method without the advantages of exclusion duodenojejunal mucosa from digestion. The major concerns of LSG are bleeding, leakage and augmented symptoms of GERD after surgery [2-7, 15, 19, 20, 22, 24]. During LGP, greater curvature of the stomach is invaginated into the gastric lumen in two or three folds by two layers of laparoscopic interrupted or running sutures. Gastric release, dilatation and prolapse (probably synonyms of the same effect in different stages) are common complications after LGP instead of bleeding and leakage. Gastric necrosis or perforation occurs rarely. Nausea and vomiting are associated with LGP very frequently [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24].

Objective
This paper presents the short-term results of the LASA-GNE trial (LAparoscopic Single-Anastomosis duodenoileal bypass with Gastric plication (SADI-GP) in the maNagEment of morbid obesity) registered under number ISRCTN12800723 and approved by the institutional review board of Kanizsai Dorottya Hospital (hospital of Nagykanizsa) under protocol number KDK-2071-2/2019. The study is aimed to assess the safety and efficacy of SADI-GP based on a prospective cohort of patients recruited consecutively. We believe that combining well researched SADI with GP instead of SG could result in better complication rates and plausible metabolic outcomes.

Study design and setting
This trial used a cohort of consecutively admitted patients aiming at the assessment of complication rates and efficacy of SADI-GP. Patient recruitment began in October 2018 and ended in June 2019 (the last operation was performed in November 2019). Preoperative evaluation followed by surgery and postoperative follow-up visits (at 1, 3, 6 and 12 months) were planned.

Participants
Patients between 18 and 65 years, with BMIs of > 40 (without comorbidity related to morbid obesity) or > 35 (with comorbidity related to morbid obesity, especially glucose metabolism) were included. Patients who had previous bariatric surgery, who had severe mental disorders (drug addiction, alcohol consumption, the use of antipsychotics), who were regarded as socially vulnerable patients, who were completely immobile, who were unable to understand the purpose of the study and bariatric surgery, who denied or withdrew their informed consent, for whom duodeno-ileal bypass was not performed during surgery or who dropped out before the 6-month follow-up were excluded.

Variables
Primary endpoints of the study were to assess the safety of the investigated method and evaluate the risks due to surgery. Secondarily, weight-loss outcomes were analysed.

Procedure
Patients were operated in French position. The operating surgeon was positioned between the patient's legs and one assistant surgeon was placed on each side. Under combined (general and peridural) anaesthesia, a skin incision was made one span (15-20 cm) under the xiphoid process, then the abdominal wall was prepared and lifted directly to prepare carbon dioxide peritoneum with a Veres needle, and an optic trocar (15 mm) was placed into the intra-abdominal cavity. Under visualisation, ports were created left (5-10 mm) and right (5-12 mm) of the umbilicus in the mid-clavicular line under the xiphoid process (10-12 mm depending on the type of liver retractor) and under the left rib arc in the front axillary line (5 mm). A liver retractor was placed through the epigastrial port, and the left upper abdomen was explored. The gastrocolic and gastrolienal ligaments were dissected besides the stomach by electrosonic cutting coagulation device (Thunderbeat, Olympus Co., Japan). A 54-F bougie was placed into the gastric lumen and guided through the pylorus. Depending on the anatomical situation, a two-layer threefold 2/0 polydioxanone (Polydox, Chirana, Czech Republic) running suture was made from fundus to antrum or a 2/0 polydioxanone (Polydox, Chirana, Czech Republic) running suture was made from fundus (one-layer onefold) through the corpus (two-layer threefold) to the antrum (one-layer onefold). The line was knotted by hand with laparoscopic manipulators. The bougie was changed to a common nasogastric tube. Standard cholecystectomy was performed. The posterior wall of the duodenum was dissected from the pancreas to the line of the gastroduodenal artery. The duodenum was dissected 3-4 cm after the pylorus by cutting-closing laparoscopic tri-stapler (Endo-GIA 60, Covidien, Ireland). Viability of the duodenal stump was preserved. The omentum majus was dissected vertically. The ileum (measured 300 cm back from the ileocaecal junction orally) was positioned tension-free antecolic and tied to the posterior wall of the duodenal stump by 2/0 polyglactin sutures (Surgicryl, SMI AG, Belgium). The proximal duodenal staple line was excised and a lengthwise ileotomy was made. A running hand-sewn end-to-side duodeno-ileostomy was prepared by a 2/0 polydioxanone barbed suture (V-Loc, Covidien, Ireland) and the line was secured by Ligamaxx clips (Ethicon Inc., USA) if necessary. Air-water proofing was performed. The oral part of the sewn ileum was connected to the stomach by 2/0 polyglactin sutures (Surgicryl, SMI AG, Belgium) to protect the anastomosis and reduce alkaline reflux. Intra-abdominal drainage was placed through the right upper abdominal port. The cholecyst was removed from the abdomen. During trocar removal, abdominal wall sanguinations were visualised. After exsufflation, the skin wounds were closed. A short video report is available at online depository.

Perioperative period
Patients routinely spent the first 36-48 h after operation in ICU. On the first postoperative day, a swallowing X-ray was performed with gastrografin (Bayer Pharma AG, Germany). If there was no leak, the nasogastric tube would be removed. Patients were advised to drink by gulps, up to 200 ml on the first postoperative day, 500 ml on the second postoperative day and so on, finally reaching 2000 ml. Routinely, 6000NE enoxaparin (Clexane, Sanofi, France) injections were administered during the first month. Compression I elastic graduated stockings were applied perioperatively. Analgesics and antiemetics were part of routine treatment. Patients were advised to take oral vitamins (some kind of complex product containing types of vitamin B and D), iron supplementation (combination of 100 mg ferric (III) hydroxide polymaltose and 0.35 mg folic acid two times daily) and oral PPI (pantoprazole 40 mg one time daily) during the first postoperative month. In case of malabsorption, vitamin and iron supplementation was prolonged until serum levels were normalised or clinical signs were diminished. PPI intake was also continued in case of persistent symptoms of GERD. The postoperative diet was adapted to the change in upper gastrointestinal tract anatomy. Nutrition was set up depending on consistency of the meal during the first 8 weeks. Appropriate fluid (1500-2000 ml distributed in 200-300 ml portions per hour) and protein intake were emphasised. Initially, daily calorie intake was advised to be kept at 900-1000 kcal (protein: 73 g, carbohydrate: 73 g, fat: 43 g) which was raised to 1200 kcal (protein: 87 g, carbohydrate: 87 g, fat: 51.6 g) and 1500 kcal (protein: 109 g, carbohydrate: 109 g, fat: 64.5 g) for women and men, respectively, after the third week. Later, patients were advised to keep to a standardised diet containing equal quantities of carbohydrate and protein (30-30%) and 40% fat (1200 kcal for women, 1500 kcal for men). No added sugar was permitted. During the first 1-3 weeks, fat intake was calculated from the natural content of dishes. Afterward, the daily addition of 5-10 g of fat to food was advised. Five meals were taken every day. If necessary, meal replacements (Fresubin Protein Energy Drink, Fresenius Kabi, Ireland) or protein additives (Protifar, Nutricia, Netherlands) were permitted to complete the suggested carbohydrate, protein and fat intake. Appropriate replacement of vitamins and trace elements was necessary. After the first 8 weeks, patients were advised to keep to a balanced weight-loss diet containing equal quantities of carbohydrate, protein and fat to maintain a negative energy balance providing a deficit of 500-1000 kcal daily. The calorie requirement of each patient was calculated by Millfin St. Jeor BMR estimation formula corrected for age, gender, height, weight and activity level. Adequate weekly physical activity was advocated.

Study size
The sample size was calculated statistically to reduce skewness. Considering a normal distribution with a statistical power of 80% and a type I error of 5%, the sample size was calculated to be 32 patients. Considering a 10% dropout rate, 35 cases were planned for inclusion in the study.

Statistical analysis
Variables with normal distribution (analysed by Kolmogorov-Smirnov and Shapiro-Wilk tests) were presented by mean and SD; non-normally distributed variables were expressed by median and interquartile range. Categorical variables were presented as number and percentage. Means of continuous normally distributed records were analysed by two-sample t-test or ANOVA. The p-value was set to 0.05.

Participants
During enrolment, 26 patients were scheduled for surgery; nine of them were excluded from the trial for different reasons, leaving 17 cases for final evaluation (15 females, mean age of included patients 40 years). Details are shown in the flow diagram (Fig. 1).

Descriptive data
All surgeries were performed laparoscopically. On average, it took 205 min to perform SADI-GP. After 10 operations, procedures became faster. In two cases, cholecystectomy was performed earlier, but one of them had an uncomplicated Meckel diverticulum that was also resected during surgery. Only two patients had verified stones in the gallbladder before surgery, but pathological examination showed chronic inflammation in all specimens and cholesterolosis (non-neoplastic polyps) in 6 of 15 cases. Patients were observed on average for 42 h in the ICU and spent 7 days in hospital. Comorbid conditions related to obesity were frequent; the characteristics of the cases are presented in Table 1. Obesity-related comorbidities had shown favourable resolution rates (hypertension: 33%, 44.4%, 77.8% and 77.8%, dyslipidaemia: 36.4%, 36.4%, 72.7% and 81.2%, prediabetes and diabetes: 54.5%, 81.8%, 81.8% and 100% at 1-, 3-, 6-and 12-month follow-ups, respectively). Symptomatic GERD was frequent. Five patients presented gastritis at baseline, all of them were cured before surgery and there was no relapse observed during follow-up. NAFLD was present at a high rate (94.1%). In the first month, more patients presented higher levels of liver enzymes, which fell at 3and 6-month follow-ups and remained stable. High levels of uric acid were presented by 52.9% of cases at baseline, decreasing to 41.2%, 35.3%, 25% and 7.1% at 1-, 3-, 6-and 12-month follow-ups, respectively.

Primary outcomes
There was no conversion, death, bleeding, VTE or 30-day readmission to hospital after the surgeries. The overall perioperative complication rate was high (29.4%). There were two severe complications (11.8%). We experienced a CD4a (pulmonary insufficiency due to chronic lung disease) and a CD3b (anastomosis leakage treated laparoscopically by stitches) complication. Vomiting occurred in three cases (CD1) which represents 17.6% of patients with mild perioperative complication rate. We did not experience gastric wall prolapse or release after surgeries. All operated stomachs showed a cone shape around the cardia on the postoperative swallowing X-ray. Among late side effects, there were no clinical signs of bile reflux or narrowing of duodeno-ileal anastomosis. Mild anaemia (treated by iron supplementation) was frequent (7.1%, 33.3% and 38.5% at 3, 6 and 12 months of follow-up, respectively) in an increasing pattern of incidence but hypoproteinaemia (16.7% and 15.4% at 6 and 12 months of follow-up, respectively) was rare. Overall nutrient deficiency (17.6%, 35.7%, 66.7% and 23.1% at 1, 3, 6 and 12 months of follow-up, respectively), diarrhoea (52.9%, 41.2%, 52.9% and 23.5% at 1, 3, 6 and 12 months of follow-up, respectively) and hair loss (47.1%, 47.1% and 17.6% at 3, 6 and 12 months of follow-up, respectively) were frequent during the first 6 months after surgery, but the occurrence of these late side effects decreased remarkably by the end of the first year. Detailed results are listed in Table 2.

Secondary outcomes
Weight-loss outcomes were very favourable representing significant improvement (two-sample t-test, p < 0.001 for all variables at 1 year) in weight loss and decrease in BMI respectively. Patients presented a mean bodyweight of 142.54 kg (mean BMI: 50.21) at baseline, which decreased to 83.96 kg (mean BMI: 29.58) at 12-month follow-up, resulting in a mean loss of 24.71%, 38.91% and 53.20% of overweight and 11.62%, 18.54%, 26.46% and 35.58% of total bodyweight at the respective follow-up timepoints. After favourable initial (at the 1-and 3-month follow-ups) results, a 37-year-old female patient presented weight regain and worsened thyroid hypofunction; however, her metabolic parameters remained within an acceptable range. Psychological assessment by using Individual Focused Cognitive Behavioral Therapy (PF-CBT) via video call revealed chronic overeating tendencies since childhood deriving from instrumental intrafamilial physical abuse and school bullying. Such unresolved traumatic events along with social isolation due to the COVID-19 pandemic and householdchore-related stress factors overloaded the subject's coping abilities, leading to excess calorie intake. Another female patient (47 years old) regained weight (10 kg of the 34 kg lost) between the 6-and 12-month follow-ups. The reasons were disturbed microsocial circumstances, chronic diseaserelated care burden on the patient and foster care of the patient's grandchild due to drug-related criminal charges against the patient's offspring. Due to the aforementioned reasons, slow but steady loss of control over eating habits was detected and interventional PF-CBT was commenced by the second author in order to reverse the weight gain.
There was no weight regain observed among the remaining patients. Most of them experienced satisfactory  6 (3 patients were without treatment) 5 (4 patients were without treatment) 2 (7 patients were without treatment) 2 (7 patients were without treatment) Dyslipidaemia 11 7 (1 patient was in remission and 3 others were without treatment) 7 (1 patient was in remission and 3 others were without treatment) 3 (3 patients were in remission and 5 others were without treatment) 2 (2 patients had high serum lipid levels and 7 others were without treatment)     Table 3.

MMPI-2 results
Patients were grouped based on the physiological parameter of percentage total weight loss (based on 12-month results) into the groups of those with values below 30 (TWL-30b) and above 30 (TWL-30a) and their data on the Clinical Scales, Revised Clinical Scales, Supplemental Scales, Content Scales and PSY-5 Scales compared. Independent sample t-tests were applied to identify any differences, which was appropriate because scores fell into the normal and high ranges on most subscales. Low scores appeared only for one subscale (High/Low scores on Cynicism); the result for this subscale is discussed separately. Based on the test scores on the physiological parameter of percentage total weight loss (based on 12-month results), five patients were included in the TWL-30b group (all participants were females; age    (Rc3) subscale, patients showed both high and low scores, so we compared the groups using a 2 × 2 ANOVA (BMI × High/Low Cynicism), and there was no statistically significant difference between the groups (F(2) = 0.393; p = 0.67), but only some participants in the BMI-35b group had low scores on this subscale, and none in the other two groups (see Suppl. 9). Along the Supplemental Scales, we did not find any significant group differences (see Suppl. 10), nor along the Content Scales (see Suppl. 11). Along the PSY-5 Scales, we found no significant group differences (see Suppl. 12). We were able to group patients based on weight loss into the groups that lost at least 50 kg in a year (WL-50a) and who lost less than 50 kg (WL-50b) and compared their data on the Clinical Scales, Revised Clinical Scales, Supplemental Scales, Content Scales and PSY-5 Scales. Independent samples t-tests were applied to identify any differences, which was appropriate because scores fell into the normal and high ranges for most subscales. Low scores appeared only for one subscale (High/ Low scores on Cynicism); the result along this subscale is discussed separately. Based on the test scores on weight loss, eight patients were included in the WL-50b group (1 male/7 females; age M = 42.50; SD = 8.65) and eight in the WL-50a group (1 male/7 females; age M = 38.87; SD = 5.14). Along the Clinical Scales, we did not find any significant group differences (see Suppl. 13), nor on the Revised Clinical Scales (see Suppl. 14). On the High/Low Scores on Cynicism (Rc3) subscale, patients showed both high and low scores, so we compared the groups using a 2 × 2 ANOVA (weight loss × High/Low Cynicism), and there was no statistically significant difference between the groups (F(1) = 0.136; p = 0.72), but there was no participant in the WL-50b group with a low score on Cynicism (see Suppl. 15). Along the Supplemental Scales, we did not find any significant group differences (see Suppl. 16

Risk of bias
Sample size is smaller than expected which could lead to insecure parameters affecting complication rates and late side effects primarily. Weight loss outcomes could be biased by low number of allocated interventions at some timepoints, but 1-year records seem to be representative. MMPI-2 testing was performed only at 1-year follow-up, therefore, the results are only referential. There was no comparator to SADI-GP, thus, all of our observations are only descriptive.

Key results
Our study showed that SADI-GP is a promising method but there are some concerns. We experienced only one complication related to surgery, which was treated laparoscopically. Late side effects of duodeno-jejunal exclusion were over an acceptable range. Our patients presented favourable weightloss outcomes; in parallel, comorbid conditions related to obesity and QoL improved as expected. MMPI-2 tests showed that subjects with a weight loss of > 30 kg tended to show higher scores on the Depression (D) and Low Positive Emotions (Rc2) scales, which was supported by higher scores on Introversion

Limitations
In general, our study has limitations due to the small sample size and study design. We did not reach the projected number of included cases because we experienced a higherthan-expected dropout rate, and the number of patients with obesity applied for screening was too low considering the strict selection criteria. There is a huge selection bias in this cohort because 88% of the study population is female. It could skew our results that there was no control endoscopic or radiologic examination scheduled for gastric plicated patients. Routine cholecystectomy was performed in 15 cases which could bias operating time and occurrence of some complications. This paper presents only short-term results; therefore, the efficacy of the procedure cannot be determined this time. Psychological evaluation lacked longitudinal data sources for comparison.

Neagoe et al. performed a comparative trial of LSG and
LGP, which confirmed similar levels of safety of the methods, but LSG was superior to LGP in terms of efficacy after a 6-month follow-up. Most of the authors concluded that LGP is comparable to LSG in terms of postoperative complications; however, Albanese et al. experienced a high revision rate (60%) of LGP due to gastric wall prolapse [18]. To our knowledge, there are two meta-analyses and one systematic review available; each of them confirmed the superiority of LSG over LGP in terms of postoperative complications and weight-loss outcomes [51][52][53]. However, El Soueidy et al. regarded LGP as an acceptable low-budget treatment modality for obesity [54]. For a decade now, laparoscopic SADI or SADJ combined with LSG (regarded as simplified DS) has earned increasing popularity among bariatric surgeons due to its favourable complication rates and weight-loss outcomes. Sanchez-Pernaute et al. reported promising results on excellent weightloss outcomes and favourable complication rates [28]. The key question is this: how long a biliopancreatic limb should be planned? Some authors measure the whole length of the small intestine, and afferent limb longitude is determined depending on BMI and comorbidities [39,55]. OAGB is performed by a short 150-200-cm biliopancreatic limb [36,37,41,55], similarly to SADJ [27]. Others suggest taking the common limb at least 300-cm distant from the ileocecal valve to avoid hypoproteinaemia and anaemia [28,30,34]. High-volume studies reporting on consecutive patients regarded SADI-SG as safe and efficient [28, 30-32, 34, 35]. Schoar et al. concluded in their meta-analysis that SADI-SG is a promising bariatric procedure regarding weight-loss outcomes, but it should be standardised due to current technical variability [29]. A meta-analysis by Lee et al., including only cohort studies, concluded that SADI-SG among BPD-DS and LRYGB is efficient as a revisional procedure after LSG [33]. There are major concerns of loop bypass, especially for OAGB, bile reflux through gastro-jejunal or -ileal anastomosis resulting in marginal ulcers and, in the worst case, oesophageal reflux leading to Barret's metaplasia [55][56][57]; this is in contrast to SADI-SG and SADJ-SG, where it is reported rarely [27,28,[30][31][32]34] and results from preservation of the pylorus (functional barrier), which prevents bile reflux in physiological conditions [26].
Elbanna et al. [45] and Mohammed and Aldaaod [46] introduced laparoscopic gastro-ileal bypass with gastric plication (Mohammed and Aldaaod added pyloric plication to the method) which is similar to but not identical with our SADI-GP, because the physiological barrier of the pylorus is ceased; therefore, bile reflux to the stomach, resulting in high rates of anastomotic ulcers, should be expected. However, each short-term study reported the absence of serious biliary symptoms. There were no anastomotic ulcers observed by Elbanna et al. (sample size of 56), but it should be mentioned that Mohammed and Aldaaod experienced anastomotic ulcers in three cases (study population of 270 patients), which were treated conservatively. The studies reported low numbers of complications (two early abdominal collections treated by ultrasound-guided drainage observed by Elbanna et al. and two late perforations treated conservatively by Mohammed and Aldaaod). Side effects such as diarrhoea, anaemia and nutrient deficiencies were infrequent [45,46]. Hair loss was described in 53% of patients treated by Mohammed and Aldaaod [46]. The trials reported favourable weight loss (EWL% ranged between 72.5 and 90%) and metabolic outcomes [45,46].
MMPI-2 tests showed that greater weight loss carries a greater probability for depression along with a lesser likelihood of positive emotional experiences; therefore, psychological support during follow-up is necessary to maintain weight loss [58]. As an introverted personality setting is examined with greater weight loss, active psychological intervention is required in order to include and maintain subjects in therapy after the surgical procedure [59,60]. As subjects with a BMI of 35-40 score significantly higher on the Low Positive Emotions (Rc2) scale, we experienced that the transition from a BMI of > 40 towards a BMI of < 35 carries the risk of such a transition evoking anxiety and fear of the changing body. This idea is supported by the significantly high scores achieved by the aforementioned group on the Aberrant Experiences (Rc8) scale, which indicates the need for active guidance from medical professionals during this transition [61,62].

Comparison with other procedures
LRYGB had hegemony in bariatric surgery over the last decades. It was challenged by LSG (part of DS) because of simplicity and favourable efficacy. Perioperative mortality rates are proven to be below 0.2%. Overall, serious complications occur in less than 6% of patients for LSG and 9% of operated cases for LRYGB, respectively. Short-term reoperation rates should occur below 3% for LSG and 5% for LRYGB. The long-term TWL% of each method is around 20% [63]. The latest systematic reviews including metaanalysis comparing LYRGB with LSG proved controversial results in terms of efficacy and safety [64][65][66]. OAGB was described to be effective and safe compared to LYRGB [67,68]. A meta-analysis comparing pylorus-preserving bariatric surgery to duodeno-jejunal bypass liner (endoscopic treatment modality) regarded surgical procedures (mainly SADI-SG) as safer than comparator. Mortality, reoperation rates, overall complications and severe complications for SADI-SG and SADJ-SG were 0.3%, 2.5%, 12.4% and 5.7%, respectively. Overall TWL% at 1 year was described as 36,9% (34,6-39%) which are comparable or even superior to LRYGB and LSG [69]. Our pilot study on SADI-GP has shown that mortality was zero, and there was no conversion, bleeding, VTE or 30-day readmission to hospital after the surgeries. Overall perioperative complication rate was high (29.4%). There was only one severe complication related to surgery (5.9%) similar to more widespread methods (LSG, LRYGB, SADJ-SG and SADI-SG). The 17.6% of patients needed additional treatment due to mild perioperative complications (vomiting) which was a little over of described for SADJ-SG and SADI-SG. It is suggested to keep the common limb at least 300-cm distant from the ileocecal valve to avoid hypoproteinaemia and anaemia [28,30,34]. We followed these instructions; however, late side effects such as mild anaemia, nutrient deficiency, diarrhoea and hair loss as a result of malabsorption occurred frequently during the first 6 months after surgery contrary to expected but the occurrence of these adverse effects decreased remarkably by the end of first year. Weight loss outcomes were at least similar to SADI-SG and SADJ-SG and superior to LRYGB and LSG. However, it should be emphasised that the overall results of our small descriptive observational study are not really comparable to complication rates and efficiency of known and widely studied methods due to high risk of bias.

Conclusion
According to our safety study, SADI-GP is a promising pylorus-preserving malabsorptive procedure, but a longterm high-volume case series or a randomised controlled trial is necessary to evaluate complication rates and weightloss outcomes. Surgical procedures initiate the process of weight loss, but psychological interventions must take over in order to maintain it, due to the widespread changes in the psyche and behaviour of subjects following surgical intervention. The lack of these will decrease the efficacy of weight control in the long term.
Funding Open access funding provided by Hospital Library of County Zala Saint Rafael. LASAGNE trial (LAparoscopic Single-Anastomosis duodeno-ileal bypass with Gastric plication (SADI-GP) in the maNagEment of morbid obesity) registered under the number of ISRCTN12800723 was funded by Kanizsai Dorottya Hospital (Hospital of Nagykanizsa) and approved by the institutional review board under the protocol number of KDK-2071-2/2019.

Declarations
Ethics approval All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed consent Informed consent was obtained from all individual participants included in the study.

Conflict of interest The authors declare no competing interests.
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