A Switch to the Duodenal Switch

Background: Duodenal Switch (DS) is a procedure that combines a Sleeve-Forming Gastrectomy (SFG) plus a biliopancreatic diversion (BPD) for the treatment of morbid obesity (MO) with a higher weight loss and resolution of comorbidities Objectives: Report our experience with 950 consecutive DS operations performed from 1994 to 2016. Setting: Mix of teaching and private institution in a county hospital of Spain. Methods: We report an observational, retrospective and longitudinal study of 950 consecutive morbidly obese patients treated by DS surgery. Results: We performed 518 open and 432 laparoscopic DS. Operative mortality was 0.84% (1.38% in DS and 0.38% in LDS), 4.84% had leaks, two had hepatic failures (0.2%) and malnutrition was present in 3.1%. At 5 years, the percentage of BMI lost was 80%, and percentage of expected BMI loss was more than 100%. Conclusions: DS is the most aggressive bariatric surgery (BS) technique, but with the best long-term weight loss. We describe operative complications and long-term follow-up guidelines. Research Article A Switch to the Duodenal Switch Aniceto Baltasar*, Nieves Pérez, Rafael Bou, Marcelo Bengochea and Carlos Serra Alcoy County Hospital and San Jorge Clinic, Alcoy, Alicante, Spain Received: 20 August, 2018 Accepted: 23 March, 2019 Published: 25 March, 2019 *Corresponding author: Aniceto Baltasar, Alcoy County Hospital and San Jorge Clinic, Alcoy, Alicante, Spain, Tel: +34 616.231.021; E-mail:


Introduction
Hess [2], measures the entire small intestine, at low bowel tension, from ligament of Treitz to the ileocecal valve and uses 50% of its length as Biliopancreatic Loop (BPL), 40% as Alimentary Loop (AL) and 10% as Common Loop (CL).
Marceau [3], used the standard BPD until 1991 and one year later he changed to DS and he was the fi rst to publish the DS [4], as parietal gastrectomy plus BPD and compared 252 BPD with distal gastrectomy and 465 DS with a 1.7% operative mortality. Lagacé [5], reported in 1995 the fi rst good DS results in 61 patients with a new type of gastrectomy. Hess [6], uses a suture to invert the gastric serosa to cover the SFG staples and avoid leakage at the staple-line. Baltasar [7,8], describes the gastric part of the operation as SFG [7,8].
To measure weight loss results the Quetelet Body Mass Index (BMI) is used. BMI = kg/m 2 , but… after reviewing 7,410 patients our mathematician developed the concept of predictive or expected BMI [28], to calculate BMI as Initial BMI (IBMI) any BMI superior to 25 and make the calculation not from IBMI but of IBMI in excess of 25. The % of excess weight lost (%EWL) are not equal in a MO patient grade 2 compared with the ones with triple obesity. Molina has reported that the expected BMI is useful [29].

DS by Open Laparotomy (ODS):
The patient is in Trendelenburg position. A supraumbilical transverse incision Is made between the two coastal margins (Figure 2 A-B). The round and triangular ligaments are sectioned. The gallbladder and appendix are removed. The open transverse approach gives better exposure and fewer hernias than the average laparotomy, but since laparoscopy its use today is restricted to re-operations.
The abdomen is closed in two layers of continuous Maxon. After weight loss, the scar shortens by one third in length ( Figure 2b) and allows the superior wound to reach the pubic area in the abdominoplasty at the body contour surgery ( Figure  2c). We started the ODS on 17.03.1994 with mean surgical times of 91 minutes.

Laparoscopic CD (LDS):
It's done by three surgeons. Six ports are used ( Figure 3). The Optical Trocar or "main port" is Ethicon # 12. It enters the abdomen under vision at the lateral edge of the right rectus, three fi ngers below the costal margin. A 10 mm central supraumbilical port is used for the mid-line camera.
There are four 5 mm ports, two sub-costal located on the right and left, one in the left hypochondrium and the other in the epigastrium used to retract the liver (Figure 3). To avoid slippage, we use Termanian trocars.
The entire small intestine is measured from the ileocecal valve to Treitz ligament with forceps at 5 cm steps to avoid lesions of the intestinal serosa. The CL is marked with a clip.
The upper AL is divided with linear stapler. The BPL starts at the fi rst part of the duodenum (D1) and joins at the union of AL-CL as end--lateral Roux-Y (RY) jejunal-ileal anastomosis (JIA) with a continuous monoplane resorbable suture. The mesenteric defect is closed with a non-absorbable suture.
The greater gastric curvature vascular supply is divided starting 3 cm distal to the pylorus and up to the angle of His. A 12 mm nasogastric probe is passed along the inner curvature of the stomach and used as a guide to divide the stomach sequentially with linear staplers starting at the pylorus. Then both gastric walls, posterior and anterior of the staple-line and the omentum are sutured together with a continuous inverting suture to avoid torsion and leakage of the gastric tube.
A retro-duodenal tunnel is created in D1, distal to the right gastric artery, which allows the duodenal division with a linear stapler before the Oddi sphincter. The distal duodenal stump is also reinforced with continuous inverting suture.
The proximal AL passes retro-colic, on the right, and a Duodenum-Ileal Anastomosis (DIA) is performed. The operation has four sutures-lines (gastric staple-line reinforcement, distal duodenal stump, DIA, and the jejunum-ileal RY anastomosis) and drainages are placed, one next to the gastric tube and the other in DIA.
All anastomoses are hand-sutured with a monolayer continuous suture. All sutures start with the sliding and selfblocking knot of Serra-Baltasar [30][31] and end with Cuschieri one [32]. The stomach is removed without a protective bag. A Maxon suture closes the 12 mm port fascia to prevent hernias. We started the LDS on 10   The fi rst occurred 6 months after surgery, included in the urgent list of liver transplantation but died due to lack of a donor. The second patient suffered liver failure three years after and she was treated successfully with a liver transplant plus BPD reversal and is healthy four years later. A patient died 13 years after ODS due to alcoholism. 4) Caloric-protein malnutrition (CPM). Thirty-three patients (3.3%) developed CPM and 24 required CL elongation. 13 of them were open without complications. In 11 cases, the CL was laparoscopically lengthened and in two of them the small intestine was injured by the dissecting forceps that easily perforated the weaken wall ( Figure 4). Both cases were diagnosed intra-operatively and repaired, but they died later due to re-leakage. Multiple hernias were found in the weak muscular wall between the mesentery vessels. These types of hernias have not been previously reported. Therefore, we recommend laparotomy for intestinal lengthening.   Catheter-related sepsis-3.

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Long-term Mortality: An acute appendicitis not diagnosed at two years. Intestinal necrosis by internal hernia at 3 years. There were other causes of death not related to the CD (cancer, melanoma, myocardial infarction, etc.)

Weight loss results
The fi gure 6 graph shows in blue the average expected BMI that was around 30 and in red the % expected excess BMI lost and that at the end was around 100%.
The fi gure 7 graph shows in blue the evolution of the average BMI over the months (it starts at 49 and ends at about 30) and in red the% of patients followed (starts at 100, continues with 38.5 at age 5, 25.8 at age 10 and ends in 0.9 at 20 years Therefore, the fi nal %EWL was excellent at 90% in these series and is probably better than with any other obesity operation. The DS is also very effective in the SSO. A patient with IBMI-100 fell to FBMI-34 ( Figure 8).

Correction of comorbidities
Diabetes type II (DM2): DS is a very effective operation to treat diabetes. 98% of our patients are normoglycemic with normal glycosylated hemoglobin. Two non-diabetic patients suffered severe hypoglycemia and the BPD was reversed.
Hypertension was corrected in 73% of cases and sleep apnea in 100%.

Quality of life
We use the Horia-Ardelt [33],

Discussion
DS has never been a popular therapy among surgeons; Hess [6], describes how after seeing a video of ours in Seatle-1996 at the ASBS Meeting, modifi ed the procedure with an invagination suture of greater curvature and only had a leak in 188 cases.
Very few surgeons continued making the DS and in fact a subdivision was created in the ASBS called "The switchers" with its own logo.
The DS remained unpopular, and we had to meet, for years, outside the congress venues as a separate group of 25-30 surgeons (Figure 9).
The unpopular "Switchers" have continued doing the intervention and many patients, even extra-national ones, knew about its advantages and looked for this therapy. We have  Three patients required an emergency tracheotomy [35,36].
In 2000, we used non-removable rigid stent [37], and then removable ones [38], to treat leaks. Nine patients required total gastrectomy [39]. In three patients we used a Y-Roux derivation [40,41] and this technique of 2007 is today the therapy of choice when the removable endoprosthesis fails [42].
Buchwald [49], at the 2004 consensus conference stated that in OM, surgery should be considered for patients with obesity greater than class IBMI 30-34.9 kg/m 2 with associated comorbidities. Morbi-mortality should be low and obtain an optimal and sustained %EWL with minimal side effects. No BS technique is 100% successful or durable in all patients and there is no single standard procedure and probably never will be. In addition, BS cannot be the solution for the 1.7 billion with OM. SFG leaks are a cause of signifi cant morbidity manifested in the specifi c SFG meetings of Deitel [50]. The DS is a long and diffi cult procedure that requires experienced and experienced surgeons. Operative mortality should be <1% and morbidity <5%. Our 0.38% mortality for LDS has been quite low. Since patients with DS have four suture lines, early detection of leaks is essential.
Mason [51] drew attention to tachycardia as the fi rst warning sign of leakage and no patient should be discharged with tachycardia.
Although our stay after LDS is 2-3 days, we instruct patients to enter to a telematic database [53,54], the pulse and temperature digitally, and notify us these parameters every four hours, for two weeks. Patients with signifi cant change in these parameters need immediate and urgent consultation. The %EWL was 81% at 12, 88% at 24 and 83% at 36 months.
Patients with HbA1C above 6% decreased from 38% to 1.4%. Biron [61], studied the quality of life of 112 patients at 8.8 years. He observed some decrease in the quality of life in the long term after the initial changes that occurred 1-2 years after the surgery, during the so-called "honeymoon period". The DS improves the specifi c quality of life of the disease in the short and long term.
Prachand [62], observed %EWL at 2 years in 350 patients of 54% in 152 GBP patients versus 68% in 198 patients with DS with only one deceased (P = not signifi cant). %EWL at 3 years were DS = 68.9% was much higher than with GB = 54.9% and showed that the DS was more effective.
Strain [63], also had greater weight loss DS than GBP. The average weight decreased by 31.2% after the GBP and 44.8% after the DS.
Topart [64 in 2002-2009 had 83 DS and 97 GBP, with IMCI >55. After 3 years of follow-up, the average %EWL was 63.7% after the GBP and 84.0% after the DS (P> 0.0001). The results were signifi cantly better with DS.
Våge [65], 2001-2008 treated 182 consecutive patients with DS without 30-day mortality. A patient needed surgery due to a leak; three patients due to bleeding and one due to leakage of bile. Six patients (3.2%) underwent surgical revision due to PCM, data similar to ours (3.3%).
In summary, patients undergoing DS constantly reduce BMI more than patients with GBP. So, why are there so few patients had DS?
Angrisani [66], reports that in 2018 there were 685,874 global bariatric operations; 92.6% primary and 7.4% revision. 96% of them surgical and 4% endoluminal. SFG-53.6%, GBP-30.1% and OAGBP-4.8% and only 1.3% LDS. Is the DS a too complex operation or the results are not so good? At the DS the SFG is irreversible but intestinal continuity can be restored to normal. The LDS can be performed in two stages, SFG as initial operation, in high-risk patients with IMCI >60.
Rabkin [67], reports that the DS is not associated with extensive nutritional defi ciencies. Annual laboratory studies, which are required after any type of bariatric operation, appear to be suffi cient to identify unfavorable trends. In selected patients, additional iron and calcium supplements are necessary.
Keshishian [68], performed a preoperative needle biopsy of the liver in 697 patients with DS. There was transient worsening of the AST (13%, P <.02) and ALT (130-160% of the reference levels, P <.0001) up to 6 months after the DS. And he observed a progressive improvement of 3 degrees in the severity of NASH and 60% in hepatic steatosis at 3 years after DS.

Type 2 diabetes
Buchwald [69], reports that DS and BPD have diabetes resolution rates that exceed 90%. In comparison, the GBP rate is approximately 70%. Tsoli [70], showed that SFG was comparable to DBP in the resolution of T2D but lower in dyslipidemia and blood pressure. In our fi rst diabetes surgery [71], a low IBMI-35 patient had a and successfully performed a LDS without SFG to treat diabetes with excellent results.
Våge [72], thinks that DS is effective in T2D, hypertension and hyperlipidemia. And that the duration of diabetes and the age of the patients are the most important preoperative predictors. DBP without SFG is still rare as the only weight loss procedure; but in patients whose clinical indications justify the omission of SFG, the isolated DBP has better weight loss results. In this series, weight loss at 2 years compares favorably with other commonly performed bariatric operations.

DS done by stages
We believe that BPD without SFG is totally reversible and this is an advantage, since the SFG can be added at any later time.
The bowel surgery of the BPD is easier in the SO patient than the infra diaphragmatic of the SFG. In addition to leakage, the most serious long-term complication of is CPM. Surgical correction is simple when using the "Kiss-X" technique" as a jejunal-jejunal anastomosis to lengthen the CL, preferably by laparotomy.
Today we are privileged with endocrinology units, compared with 15 years ago when they did not believe in surgery and their support was very limited. So is the support of bariatric nursing and nutritionists.