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International Journal of Open 5 (2016) 11–19

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International Journal of Surgery Open

journal homepage: www.elsevier.com/locate/ijso

Review Article Overview of Elroy Patrick Weledji *

Department of Surgery, Faculty of Health Sciences, University of Buea, Cameroon

ARTICLE INFO ABSTRACT

Article history: Gastric bypass surgery is indicated for several clinical reasons including benign and malignant upper gas- Received 7 June 2016 trointestinal tract pathologies. Any gastric resection or bypass procedure interferes with gastric emptying Received in revised form 17 September and the aim of reconstruction is to minimize the disturbance to the upper gastrointestinal physiology. 2016 Gastric bypass procedures induce early satiety, with or without concomitant impaired absorption of nu- Accepted 19 September 2016 trients, and offer the best solution for morbid . The long-term health benefits of gastric bypass Available online 21 September 2016 surgery for morbid obesity must be found to outweigh the operative risks and side-effects of gastric bypass and thus patient selection is fundamental. The aim of the study was to review the indications, compli- Keywords: Gastric bypass cations, sequelae and outcome of gastric bypass procedures. Indications © 2016 The Author. Published by Elsevier Ltd on behalf of Surgical Associates Ltd. This is an open Complications access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Sequelae

1. Introduction 2. Gastrojejunostomy

The history of gastric bypass surgery began in 1880 when the By diverting away from the , anastomo- Polish surgeon Ludwik Rydygier performed a for sis of the to a loop of was once used to treat [1]. In 1885, the Austrian surgeon Theodor duodenal ulcer but carried a high recurrence (50%) rate [12]. Gas- Billroth (Fig. 1) performed a first-stage gastrojejunostomy to alle- trojejunostomy was then used as a drainage procedure following viate the symptoms of an obstructing large pyloric tumour followed truncal for peptic ulcer disease but has fallen into disuse by a second-stage resection of the tumour with restoration of gas- since the advent of effective medical treatment to suppress gastric troduodenal continuity [1,2]. Most modern forms of with acid output and antral invasion [13,14]. Lapa- gastrojejunal (Billroth II) are modelled on this oper- roscopic gastrojejunostomy (LGJ) has been proposed as the technique ation and described for the treatment of peptic ulcer disease in 1911 preferred over open gastrojejunostomy for relieving gastric outlet [2–4]. With the success of antral Helicobacter pylori eradication triple obstruction (GOO) due to malignant and benign disease with im- therapy for peptic ulcer disease which includes antibiotics and a re- proved outcome and an acceptable complication rate [15].

versible chemical vagotomy with H2 receptor antagonist or proton Gastrojejunostomy would also bypass congenital pre-ampullary du- pump inhibitor, surgery is now indicated only for the emergency odenal obstruction from a duodenal web/atresia/stenosis and an complications of perforation, severe vomiting from pyloric steno- annular , with no or minimal early or long term compli- sis and haemorrhage [5]. It was also well recognized that Billroth cations including [16]. Although resection of a primary II (partial) gastrectomy is associated with and several gastric tumour provides better palliation than bypass surgery pro- variations of this procedure have been used effectively in the sur- vided the patient’s general health will allow this, patients with gical treatment of morbid obesity with benefit lasting for up to 10 unresectable distal gastric tumours may benefit from a high antecolic years [4,6–11]. The restriction of volume of ingested food togeth- gastrojejunostomy [17–19]. The control of the rate of delivery of the er with altered absorption of nutrients, especially contributes gastric contents to the that allows adequate mixing to achieving the weight loss and the malabsorptive procedures alter with and pancreatic juices and avoids overwhelming the di- the digestive process in different ways [8–11]. The aim of this review gestive and absorptive capacity of the small intestine requires an was to evaluate the common gastric bypass procedures with regard intact and innervated . The importance of attempting to pre- to their indications, sequelae and outcome. serve normal gastric emptying in gastric bypass procedures without compromising oncological results is seen with the more physio- logical post-operative digestive function of the pylorus – preserving partial for pancreatic head cancer than with the partial stomach resection of the classical Kausch–Whipple * Department of Surgery, Faculty of Health Sciences, University of Buea, PO Box 126, Limbe, S. W. Region, Cameroon. Fax: 237 633322179. procedure [20]. The Whipple’s procedure is also occasionally indi- E-mail address: [email protected]. cated in cases of duodenal or pancreatic head trauma. Following a

http://dx.doi.org/10.1016/j.ijso.2016.09.004 2405-8572/© 2016 The Author. Published by Elsevier Ltd on behalf of Surgical Associates Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/). 12 E.P. Weledji / International Journal of Surgery Open 5 (2016) 11–19

tomy) (Fig. 1) [2–4]. The Polya gastrectomy with retrocolic end-to- side gastrojejunostomy has become a commonly performed modification of the Billroth II procedure [2]. Franz von Hofmeister described a partial gastrectomy with a retrocolic gastrojejunos- tomy involving the greater curvature [2,28]. Reconstruction following partial gastrectomy may be simple or difficult depending partly on the build of the patient and partly on the extent and nature of the disease process. Thus Billroth II gastrectomy is usually used for an emergency perforated large duodenal ulcer not suitable for simple omental patch closure and when a duodenal anastomosis (Billroth 1) cannot easily be made [29]. A gastrectomy is not a bypass procedure and is suitable for a resistant benign gastric ulcer after excluding malignancy [14,27]. The Billroth II is associated with prob- lems of bile reflux into the gastric remnant and oesophagus, and a higher risk of stomal ulceration. Thus, approximately two-thirds of stomach should be resected to avoid repeated antral exposure to bile [6,14]. For the theoretical benefits of delaying gastric emptying Fig. 1. Diagram of Billroth II gastrectomy. and preventing reflux of duodenal contents into the stomach, a Hofmeister ‘valve’ can often be fashioned by reducing the stoma length to around 5 cm through closing part of the opening in the gastric retroperitoneal duodenal injury, options for duodenal repair may stump and the rest being used for the actual anastomosis [28]. include a pyloric exclusion effected through a . The pyloric ring is closed with a continuous suture or stapling which breaks down 3.1. Complications after several weeks. The procedure is combined with a gastrojeju- nostomy and the addition of octreotide and intravenous acid Billroth II gastrectomy was favoured for many years for its rel- suppression may improve duodenal healing and decrease stomach atively low peptic ulcer recurrence rate (less than 5%) [2,4,6]. ulceration. Roux-en-Y loop (Roux-en-Y duodenojejunostomy) drain- However, it has a high mortality and complication rate [6,14]. Leakage age of the defect from significant tissue loss in the second part of may occur from either the duodenal stump or from the anastomo- the duodenum is the procedure of choice in the stable patient [21]. sis. Leakage from the duodenal stump is usually due to afferent loop Both the duodenum and the are triply bypassed with a obstruction. This risk is reduced by the formation of a Roux-en-Y gastroenterostomy, and a retrocolic Roux-en-Y hepatico- reconstruction. If there is controlled leak without or gener- for a duodenal obstructive, locally-advanced pancreatic head car- alized conservative treatment is indicated with parenteral cinoma [22]. However a prophylactic gastrojejunostomy may suffice nutrition. Otherwise exploration is required to drain any sepsis and for an obstructive unresectable periampullary carcinoma [23]. to establish drainage of the afferent loop. A useful technique for the latter is to insert a T tube into the duodenum and, therefore, es- 2.1. Complications tablish a controlled fistula, and to decompress the afferent loo obstruction [6,30,31]. It is unlikely that direct suture of a leak will Early technical complications from a gastrojejunostomy would be feasible. Treatment of a gastrojejunal leak is problematic. More include: (a) haemorrhage which is usually from the gastric side of commonly the leak is delayed, occurring 7–14 days postopera- the anastomosis and usually only starts when the clamps are re- tively. If there are clinical features to indicate that this is limited leased, by which time the lumen is not visible. It occasionally requires and localized, then conservative treatment with nutritional support, exploration; (b) leakage may occur as a result of tension on the anas- gastrointestinal decompression and antibiotics is indicated .Other- tomosis. Difficulty in bringing the stomach and jejunum together wise, reoperation is required. without tension may require opening the gastrocolic omentum and performing a retrocolic posterior gastroenterostomy. Otherwise, there 3.2. Side effects and post-prandial sequelae is little advantage over the simple antecolic gastroenterostomy [24,25]; (c) an internal if the mesenteric defects are not closed; 3.2.1. Early satiety (d) sepsis, either as a wound infection or an intraabdominal ; Early satiety arises from the loss of reservoir function of the (e) early obstruction follows oedema around the stoma or kinking, stomach and it is important to obtain good early dietary advice and or, later due to progression of malignancy especially if done for pal- limit meal size. The excision of 80% of the stomach leads to reduced liation. Late complications include stomal ulceration which can be gastric volume resulting in early satiety and hence weight loss. prevented by proton pump inhibition and pancreatitis due to af- Gastric bypass surgery not only reduces the gut’s capacity for food ferent loop obstruction [6,24]. but also dramatically lowers levels compared to both lean controls and those that lost weight through dieting alone [32,33]. 3. Billroth II gastrectomy Ghrelin, the “hunger hormone”, is a peptide hormone produced by ghrelinergic cells in the which functions as a The Billroth II gastrectomy is often indicated for refractory peptic neuropeptide in the central nervous system. Besides regulating ap- ulcer disease and gastric adenocarcinoma [14,26,27]. Except in the petite, ghrelin also plays a significant role in regulating the aged, most surgeons now opt for a partial gastrectomy to treat a distribution and rate of use of energy [34]. It prepares the body for resistant peptic ulcer after excluding acid hypersecretion from a pan- food intake by acting on hypothalamic brain cells to increase hunger, creatic islet cell gastrinoma [14,26]. Following resection of the distal gastric acid secretion and gastrointestinal motility [35,36]. Ghrelin stomach, reconstruction can be performed by either fashioning a is secreted when the stomach is empty, but secretion stops when new lesser curve and creating an end-to-end gastroduodenal anas- the stomach is stretched. Bariatric involving excision of tomosis (Billroth I gastrectomy) described in 1881, or, by an end- the fundus as in vertical reduce plasma ghrelin to-side anastomosis of the gastric remnant to a loop of jejunum, levels by about 60% in the long term [37]. However, studies are con- with closure of the duodenal stump (Billroth II or Polya gastrec- flicting as to whether or not ghrelin levels return to nearly normal E.P. Weledji / International Journal of Surgery Open 5 (2016) 11–19 13 with gastric bypass patients in the long term after weight loss has lowing a meal (late dumping). Dietetic input is crucial and involves stabilized [38]. reducing amount of carbohydrate in main meals with regular glucose in-between (glucose tablets) [6,39,42]. 3.3. Post-prandial sequelae 3.3.3. Diarrhoea There is a distressing array of new gastrointestinal symptoms Diarrhoea is caused by truncal or inevitable vagotomy, early (‘post gastrectomy syndrome’) resulting from the loss of reservoir dumping, and bacterial overgrowth [39,41,42]. The combination of function, denervation, disruption of the pyloric mechanism and the loss of gastric acid and formation of blind loops results in accumu- type of reconstruction. Post gastrectomy syndromes include lation of aerobic and anaerobic organisms normally found in colon. metabolic/nutritional alterations, , bile reflux gas- Faecal bacteria release toxins that destroy brush borders vital to di- tritis, , afferent/efferent limb syndromes, the Roux gestion and consume B . They deconjugate bile acids syndrome and postvagotomy diarrhoea. About 25% of patients will essential for normal fat absorption in the proximal small intes- develop post gastrectomy syndrome but only 1–4% develop severe tine. The increased faecal result in steatorrhoea and weight loss. debilitating symptoms. It is made worse by bad technique. Too ex- Investigation involves 14C glycocholate breath test and treatment in- tensive a resection predisposes to a high incidence of postprandial cludes the antibiotics (metronidazole/neomycin) and (fresh symptoms including early dumping that severely limits calorie intake unpasteurized yoghurt) to inhibit recolonization with and after an- [14,39]. tibiotics. Relative pancreatic insufficiency may also result in steatorrhoea but once bacterial overgrowth is excluded, it can be 3.3.1. Early dumping treated with pancreatic enzyme supplementation (Creon). Post va- Post gastrectomy complications may occur as vasomotor gotomy diarrhoea is due to vagal denervation leading to intestinal ‘dumping’ due to rapid gastric evacuation from loss of pyloric reg- dysmotility, rapid gastric emptying of liquids, hypoacidity, malab- ulation and receptive relaxation resulting in a hypertonic load to sorption of bile acids and bacterial overgrowth in the proximal bowel. the small intestine triggering autonomic reflexes and release of va- Severe form of post vagotomy diarrhoea may have 10–20 epi- soactive peptides. Fluid shifts can cause hypotension triggering sodes per day, often explosive with no temporal relationship with autonomic catecholamine surge. Multiple gut hormones impli- food and occurring at all times even during sleep. It is associated cated include serotonin, vasoactive intestinal peptide (VIP), with malnutrition, weight loss, and weakness [6,42].1%ofpostva- (CCK), neurotensin, peptide YY, enteroglucagon etc. gotomy diarrhoea are refractory to medical treatment (dietary The rapid filling of proximal small intestine with hypertonic food modifications, bile chelator (cholestyramine), oral neomycin, also leads to rapid movement of fluid into the gut from extracel- antidiarrhoeal agents) and severe enough for surgical interven- lular space resulting in diarrhoea. The characteristic symptoms of tion. The antiperistaltic jejunal interposition 75–100 cm from the early dumping are epigastric fullness, sweating, faintness and pal- ligament of Treitz or the Cuschieri reversed distal ileal onlay graft pitations 30 min after eating and may last for an hour. These can gives relief for the majority [43], lead to food avoidance with reduced quality of life and malnutri- tion. It is more troublesome following subtotal gastrectomy or where 3.3.4. Bilious vomiting pylorus is destroyed or bypassed. Dumping symptoms are quite Bile reflux gastritis is more common after Billroth II gastrec- common in the first weeks or months but improve over the months tomy and less with Roux-en-Y procedure. It commonly occurs after from small bowel adaptation or unconscious modification of diet gastric reconstruction with debilitating symptoms in 1–2%. The symp- [40,41]. 1–2% have debilitating symptoms but because of genuine toms of alkaline bile reflux are epigastric discomfort, heartburn, and reassurance to the patient, dietary advice to eat small meals, re- vomiting. Persistent reflux can lead to stricturing and strict carbohydrate intake and avoid too much fluid less than 1% [43,44]. It would be diagnosed by upper gastrointestinal endosco- requires surgical intervention. In many patients there is develop- py and Tech 99M HIDA scanning. Gastric emptying study would rule ment of malnutrition, manifested as anaemia and weight; loss in out gastroparesis [44,45]. Medical management with PPIs and H2 the first few months after operation to a new level which then stays blockers is rarely helpful thus requiring revisional surgery. Biliary steady [14,41]. diversion is used most often for severe bilious vomiting or if symp- As many of the postgastrectomy problems are due to by-pass of toms are unremitting as treatment options are limited and only often the duodenum and loss of gastric capacity, dumping may be di- successful. A simple version is jejuno-jejunostomy between the af- minished by conversion to a Billroth I anastomosis, a Roux-en-Y ferent and efferent limbs of a gastrojejunostomy (Uddin loop) where reconstruction or by interposing a 10–15 cm segment of proximal the former is quite long. An alternative common variety is a sub- jejunum aimed at slowing down gastric emptying [14,27]. Unfor- total (80%) gastrectomy with Roux-en-Y reconstruction with the tunately, the use of gastric pouches or jejunal interpositions has not efferent loop some 40–50 cm distal to the stoma or lengthening of significantly improved on the results of more standard reconstruc- Roux loop which gives 80% relief [46]. Again proton pump inhibi- tions. A particular hazard of jejunal interposition is an increased risk tion would reduce the risk of gastrojejunal ulceration [14]. of bile and alkaline reflux with consequent peptic ulceration at the Gastro-oesophageal reflux disease (GORD) is more prevalent as new gastrojejunal junction. The defect of normal peristalsis in the (BMI) increases. There is reduced long-term ef- long jejunal limb may also result in voluntary and involuntary re- fectiveness of anti-reflux () procedure in obese gurgitation. And so this operation should only be used in those with patients (BMI >30). Laparoscopic Roux-en-Y gastric bypass is the most severe degree of dumping or small stomach syndrome and a proton effective and recommended option as it treats GORD, reduces weight, pump inhibitor (PPI) given. The beneficial effect of the Roux-en-Y and improves [47]. Likewise, bile reflux following is thought to be due to transection of the neural plexuses that ef- gastric bypass for morbid obesity will benefit from the very effec- fectively slow gastric emptying in the long jejunal limb [41]. tive and much simpler anti-reflux (laparoscopic Nissen fundoplication) procedure than revision surgery [48]. 3.3.2. Reactive hypoglycaemic attacks Gastroparesis is delayed gastric emptying in the absence of me- Complex neurohumoral response produces unpleasant gastro- chanical obstruction. It is the most common (50%) of the post intestinal and cardiovascular symptoms. Rapid carbohydrate gastrectomy syndromes especially with associated truncal va- absorption stimulates excessive or asynchronous secretion gotomy, and, generally inversely proportional to the extent of gastric causing a rebound hypoglycaemia, blackouts, and seizures 2–3 h fol- resection [49,50]. The patient is unable to tolerate diet 7–14 days 14 E.P. Weledji / International Journal of Surgery Open 5 (2016) 11–19 after surgery but the vast majority improves with time or with growth in the jejunum. The effects are complex, but prokinetic agents. Other causes i.e. metabolic (electrolyte, endo- of fat, B12 and other B vitamins is usually present. A course crine, medications), mechanical (stoma oedema, small leaks, of broad-spectrum antibiotics will usually temporarily restore adhesions, kinking, haematoma, intussusception, stricture) should vitamin B12 absorption to normal, but complete cure may require be ruled out. Sometimes surgery is required with the original op- revisional surgery [6,14,53]. Patients should be supplemented with eration dictating the corrective procedure, i.e. further resection vitamin B during and after treatment. malabsorption following a partial resection. Most advocate R-Y reconstruction and results in osteomalacia especially in post-menopausal women. Thus completion vagotomy [51] . all patients >70 years would receive calcium supplements and undergo 5-yearly assessments for metabolic bone disease. 3.3.5. Afferent/efferent loop syndromes Afferent loop syndrome is a mechanical problem with partial ob- 4.2. Iron deficiency anaemia struction of the afferent limb from kinking, angulation, stenosis or adhesions. The afferent limb being almost always 30–40 cm or longer Iron deficiency anaemia is present in 40–50% of patients fol- is a predisposing factor and always occurs with a Billroth II bypass. lowing partial gastrectomy [42]. In addition to impaired dietary Treatment is always surgical. It entails either revision of Billroth II, intake, is associated with impaired absorption of iron conversion of Billroth II to Billroth I, conversion of a Billroth II to in the duodenum and jejunum as reduced ferrous (Fe2) rather than R-Y with a long Roux limb and complete vagotomy to prevent mar- food ferric (Fe3) ion is absorbable. Iron malabsorption is not nor- ginal ulcer or fashioning an entero-enterostomy below the stoma mally an issue unless vegetarian, as small intestine takes over if adhesions are present [30]. The Chronic type is more common. absorption. Iron and vitamin C supplements should be considered The severe post prandial pain, bile and pancreatic secretions build for the first post-operative year [42,53]. up in the afferent limb until the intraluminal pressure overcomes the obstruction resulting in projectile bilious vomiting with im- 5. Gastric cancer mediate relief of pain. The efferent loop syndrome is less common and difficult to distinguish from afferent loop syndrome or bile reflux The risk of Gastric malignancy in the remnant stomach is in- gastritis. It is usually due to adhesions or an internal hernia of the creased about 4-fold. The exact mechanism is unclear, but limb behind the gastrojejunal anastomosis and treatment is always achlorhydria, atrophic gastritis, persistent bile reflux, denervation surgical. of the and bacterial invasion of the gastric stump have been regarded as possible aetiologies [54,55]. The gastric 3.3.6. The Roux syndrome mucosa of the patients who underwent gastric surgery for malig- The Roux syndrome is a complex of symptoms including post nancy tends to develop recurrent cancer, less than 10 years after prandial epigastric fullness, nausea, intermittent vomiting and often surgery at the anastomosis site and new cancers at the non- weight loss. It is thought to be the result of an atonic roux limb that anastomosis site. Those patients with initially benign disease may impedes gastric emptying. Studies have demonstrated that it is a develop cancer but more than 10 years after at the anastomosis site result of loss of the duodenal pacesetter potentials which are fastest [56]. By attenuating the chronic gastritis–metaplasia–dysplasia– in the duodenum and spread distally to the terminal . The fre- carcinoma sequence, there is a role for H. pylori eradication therapy quency is decreased when the jejunum is resected and ectopic in preventing anastomotic recurrence or a new primary [27,56]. pacemakers spread retrogradely to the stomach. It is thus com- moner with a large gastric remnant and after truncal vagotomy. 6. Bariatric surgical procedures that involve gastric bypass Treatment is with a trial of prokinetic agents or aggressive gastric resection with R-Y reconstruction [52]. Morbid obesity defined as a body mass twice ‘ideal’ (Body mass index >39 kg/m2) has a high health risk and excess mortality [7]. 4. Nutritional problems The National Institute of health and Clinical Evaluation (NICE) guide- lines (2006) recommend as a treatment option for Malnutrition following gastric bypass is usually due to failure people with morbid obesity (BMI >40 kg/m2) or who have lower BMI to ingest sufficient calories especially in total gastrectomy pa- (35 kg/m2) plus other significant disease such as type 2 mel- tients. Malabsorption is a rare cause of malnutrition in non- litus and that could improve if they lost weight. Because bariatric gastric bypass surgery. Carbohydrate absorption is usually of the risks, surgery is only offered when all appropriate non- satisfactory but protein and particularly fat absorption is reduced surgical measures are unsuccessful [8]. Several variations of Billroth resulting in weight loss. Close dietetic follow-up should ensue after II gastrectomy as a form of biliopancreatic bypass have been de- bacterial overgrowth, early satiety, dumping, and relative pancre- scribed and not surprisingly the more complex operations are atic insufficiency have been excluded. associated with a higher incidence of morbidity [9]. The most com- monly performed procedure is the Roux-en-Y gastric bypass (RYGB)

4.1. Vitamin B12 deficiency and macrocytic anaemia [10]. Biliopancreatic diversion (BPD), with or without (BPD-DS), is less commonly performed but is often consid-

As vitamin B12 is bound to secreted by the pari- ered in extremely obese individuals [11]. All procedures can be etal cells in the body and fundus of the stomach and absorbed in performed laparoscopically with a lower rate of complications such the terminal ileum, there is virtually no absorption of B12 post gas- as wound infection and incisional [57,58]. trectomy. B12 deficiency is always seen following total gastrectomy and in about 50% of those patients who undergo partial gastrec- 6.1. Roux-en-Y gastric bypass (RYGB) tomy. Methyl-methionine testing is more accurate than serum B12 in the presence of proton pump inhibitor use. Vitamin B12 deficien- RYGB is a combination of both restriction and malabsorption. The cy usually takes some years to develop because of the large body creation of a small stomach pouch leads to early satiety combined stores of the vitamin [6,42]. All gastrectomy patients require with the bypassing of the stomach, duodenum and up to 200 cm 3-monthly hydroxocobalamin injections. The stagnant loop syn- of jejunum leading to malabsorption. Release of distal gut hor- drome which arises as a consequence of anatomical abnormalities mones and changes in taste also have a role in the mechanism of of the small intestine including blind loops results in bacteria over- action. Technically, the stomach is divided (stapled) into an upper E.P. Weledji / International Journal of Surgery Open 5 (2016) 11–19 15

Fig. 2. Diagram of Roux-en-Y gastric bypass.

gastric pouch, which is 15–30 ml in volume, and a lower gastric remnant. The gastric pouch is anastomosed to the jejunum after it has been divided some 30–75 cm distal to the ligament of Treitz; this distal part is brought up as a ‘Roux-limb’. The excluded biliary limb, including the gastric remnant, is connected to the bowel some 75–150 cm distal to the gastrojejunostomy (Fig. 2) [53]. The small size of the upper gastric pouch is so reduced that it “restricts” or limits the amount of food intake. It also provides satiety with smaller portions of food. The lower gastric remnant no longer receives, stores, and mixes food but remains secretory. The malabsorptive element Fig. 3. Omega loop mini gastric bypass. in gastric bypass is achieved as a result of the Roux-en-Y forma- tion “bypassing” the upper part of the intestine. The length of the Roux-en-Y limb was determined by the patient’s BMI; 100 cm for dysplastic changes of the gastric and oesophageal mucosa. As a result, those with a BMI of up to 48 kg/m2 and 150 cm for patients with a MGBP remains a controversial subject, particularly as only one higher BMI. This surgery can result in two-thirds of excess weight monocentric randomized trial has compared it to the RYGBP, which loss within 2 years, albeit, with specific nutritional deficiencies re- remains the gold standard [62]. quiring replacement [8–10,53]. The complication rates are about 10% in expert centres [10]. The main technical problem after gastric bypass is anastomotic leakage, which in large series may reach 5% 6.3. Biliopancreatic diversion [5]. It is a feared early complication appearing most commonly at the gastrojejunostomy in RYGB with the incidence associated mor- Bilio-pancreatic diversion (BPD) is a combination of being ini- tality of 0.1% [53,58,59]. Higher BMI, male gender, re-operation, older tially restrictive but ultimately malabsorptive. Technically, BPD involves age and surgeon’s experience are associated with higher anasto- a distal gastrectomy leaving a proximal stomach volume of 150– motic leakage rates [60,61]. 400 ml. Depending on the BMI the ileum is divided 260–360 cm proximal to the ileocecal valve, and the alimentary limb is con- 6.2. Omega loop mini gastric bypass (MGBP) nected to the gastric pouch to create a Roux-en-Y gastroenterostomy. An anastomosis is performed between the excluded biliopancreatic MGBP is being promoted as a quick and effective alternative to limb and the alimentary limb 60 cm proximal to the terminal ileum the standard Roux-en-Y gastric bypass procedure. It works both by (Fig. 4). There is 1.1% 30 day mortality and a predicted 70–80% weight restricting food intake at any one time, and by altering gut hor- loss at 2 years [11,63]. mones involved in appetite control. It seems more efficient on weight Bilio-pancreatic diversion with duodenal switch (BPD-DS) is mildly loss (70–80% at 2 years) and co-morbidities than the RYGBP, with restrictive and mainly malabsorptive. It is technically a modifica- the advantage of being less technically difficult and less morbid, es- tion of the BDS incorporating a sleeve gastrectomy and a longer pecially for multi-complicated obese and/or the super obese. There common limb. In BPD-DS, a vertical sleeve gastrectomy (SG) is con- is immediate improvement of diabetes, with some patients coming structed and the duodenum is divided 4 cm distal to the pylorus. off insulin within a few days post-surgery [62]. It consists of a unique The small bowel is divided at mid-point and the distal small bowel gastro-jejunal anastomosis between a long gastric pouch (restric- (alimentary limb) is anastomosed to the duodenum. The ilio- tive part) and a jejunal omega loop of 150–200 cm (malabsorptive pancreatic limb (proximal small bowel) is anastomosed to the ileum part) (Fig. 3). In effect, therefore, about 2 m of small bowel has been 100 cm proximal to the terminal ileum (Fig. 5) [64]. There is a pre- bypassed before absorption of food (and calories) can take place. dicted 75–80% excess weight loss at 2 years especially as the excision Fewer calories absorbed means weight loss. It is clear that in the of the fundus in the sleeve gastrectomy would decrease circulat- case of the MGBP there is only one anastomosis, whereas in ing Ghrelin and reduce appetite [63]. However, the outcome of sleeve the RYGBP there are two – an upper and a lower. Because of this gastrectomy when used primarily is the same as gastric bypass the MGBP can be done in less time than the RYGBP and – at least [61,63]. In BPD-DS, leakage from the staple line is more common theoretically – with fewer early complications. However, this pro- than anastomotic leakage and the total enteric leakage rate is 5% cedure could be at risk of biliary reflux and anastomotic ulcers with [65]. Dumping syndrome and anastomotic ulcers are less likely as 16 E.P. Weledji / International Journal of Surgery Open 5 (2016) 11–19

Fig. 4. Diagram of biliopancreatic diversion.

Fig. 6. (a, b) Single anastomosis duodeno-ileal anastomosis (SADI) procedure.

excess weight loss 5 years after SADI procedure remains compa- rable to the DS at 90% (compared with 50–70% for the sleeve or bypass) [67]. Fig. 5. Diagram of biliopancreatic diversion with duodenal switch. 7. Complications compared to a BPD procedure because of the preservation of the Patient education, thorough pre-operative work-up and regular pylorus in BPD-DS [65]. follow-up avoid most complications of bariatric surgery. The surgery- related complications are the usual complications of gastrointestinal 6.4. Single anastomosis duodeno- (SADI) surgical procedures and are managed similarly. These include haemorrhage, anastomotic leak, and anastomotic strictures [68–70]. 10–20% of patients have a sub-optimal result following bypass The complications general to any abdominal operation include pneu- or sleeve surgery. BPD-DS is quite a significant malabsorptive pro- monia, , urinary retention and ileus. Small cedure as there is usually only 1 m of ‘common’ limb of small bowel. bowel motility returns within a few hours and gastric and colonic The extra weight loss in BPD-DS is offset by a significant risk of motility after a few days, depending on the degree of surgical trauma protein or vitamin deficiency unless they are assiduous with their [7–9]. diet, and a poorer quality of life from diarrhoea (6–8 times per day). Single-anastomosis duodeno-ileal bypass with sleeve gastrec- 7.1. Management of side-effects of bariatric surgery tomy is a simplification of the duodenal switch that may behave as a standard biliopancreatic diversion but easier and quicker to The early unfavourable side effects of the bariatric gastric bypass perform. Given its effectiveness as a primary surgery it is hypoth- surgery are dehydration and constipation, and the dumping syn- esized that it would be successful as a second-step operation. The drome. Dehydration and constipation is a common problem and anastomosis between the duodenum and the small bowel is central patients must get used to drinking on a regular basis aiming for 1.5– to the procedure, and with a ‘common limb’ of small bowel mea- 2 l/day. Re-education and occasional laxatives are advised. Almost suring 3 m long the increased bowel frequency is much less 85 percent of patients who have gastric bypass (bariatric) surgery compared to BPD-DS (Fig. 6a,b) [66]. Initial reports suggest that the will experience the ‘dumping syndrome’ but surgical revision is a E.P. Weledji / International Journal of Surgery Open 5 (2016) 11–19 17 last resort [7–9]. Dumping syndrome requires re-education of patient dures and new surgical techniques where the mesentery windows with avoidance of precipitating food stuffs. Highly restrictive gastric are surgically closed may reduce the rate to as low as 1% [77]. pouch patients are advised to eat low volume meals frequently up Incisional hernias can occur but are less common with the in- to 6 times a day and avoid a carbohydrate load which can lead to creased use of laparoscopic techniques [58,59]. The risk of additional dumping [71]. Although the mass is small, stoma ul- surgery for symptomatic from the inadvertent va- ceration remains a problem. Anastomotic ulcers are usually late gotomy is prevented by a prophylactic during the complications of bariatric surgery and occur in 2% of patients within bariatric gastric bypass procedures [7–11]. Hypersideroblastosis is the first post-operative year, and then in 0.5% for up to five years an uncommon problem due to hyperplasia of the B cells of the pan- [72]. They are common in smokers and patients who are H. pylori creas as a result of excessive weight loss giving rise to chronic positive. Such ulceration may respond to proton pump inhibition hypoglycaemia. Pancreatic resection may be required [71]. but revisional surgery may be required if the ulcer is resistant. Serum gastrin levels may become excessive and the excluded stomach may 8. Revision gastric bypass (bariatric) surgery require resection [60,61]. A fistula between the pouch and the re- maining stomach must be excluded [71]. As the number of primary bariatric procedures increases so does Nutritional and vitamin deficiencies are late complications and the rate of re-operations as a consequence of either a failed primary patient compliance is the major cause of such problems. BPD and procedure or complication. It is important to evaluate whether the BPD-DS would initially require a post-operative diet high in protein cause is a technical failure or due to poor patient compliance. Dis- (60–80 mg) [42,73]. Vitamin supplementation on a daily basis is es- cussion at the bariatric MDT is important in managing such patients sential and a B12 injection at maintenance dose usually suffices [73]. with re-referral to both dietetics and psychology. Redo bariatric Internal hernias may easily develop after laparoscopic gastric bypass surgery is associated with a higher mortality (2%) and morbidity in which small mesenteric defects (transverse mesocolon, entero- (13% leak rate) compared with the primary operation [71]. Ana- enterostomy or behind the Roux limb) can be created and there are tomical assessment includes plain radiography, contrast swallows, fewer adhesions to tether small bowel loops and prevent them from and contrast follow-through studies for a ‘road map’ of the surgi- herniating [74]. In addition patients who have greater degree of cally altered anatomy of the upper GI tract. is a useful weight loss after laparoscopic Roux-en-Y gastric bypass may be more adjunct in looking at anastomotic strictures, ulcers and assessing prone to internal hernia because of loss of the protective space- pouch sizes. Blood tests are needed for a full haematological and occupying effect of mesenteric fat [75]. The reported frequency ranges biochemical profile including trace elements and vitamin D. The from 0.4% to 5.5% in RYGB [76]. Long-term data over seven years revisional surgical approaches may include reversal of the obso- record a hernia rate of 38% in BPD/BPD-DS [77]. High index of sus- lete jejunal–ileal bypass (high incidence of malabsorption), reversal/ picion is required in all patients with abdominal pain with or without revision of Roux-en-Y gastric bypass and BPD/switch for small . Delayed diagnosis may lead to life- malabsorption, removal of eroded pre-anastomotic rings in threatening complications of strangulation in the early or late post- Roux-en-Y bypass pouches (e.g. Fobi ring) and revision of gastric operative period [76,77]. Although the laparoscopic approach may pouches, gastrojejunostomies, jejunal-jejunostomies, remnant gas- result in higher rates, closure of potential defects at time of primary trectomies for enlargements, strictures, and gastrogastric fistulae, surgery is not, however, universal. Standardization of the proce- respectively [53,78,79]. These revision procedures carry with them

Table 1 Summary of gastric bypass procedures.

Procedure Principle of action Malabsorptive/bypassed limb Mean excess 30-day Side effects weight loss mortality (%)

Billroth II gastrectomy Non- primary bariatric 50–70% at 2 yrs 0.5 Bile reflux gastritis, stomal (restrictive) ulcers, dumping syndrome Diarrhoea Mild B12 deficiency Iron deficiency anaemia Roux-en-Y gastroduodenal Primary bariatric (restrictive Gastric pouch (15–30 ml) 60–80% at 2 yrs 0.1 Dehydration and constipation, bypass and malabsorptive) 100 cm jejunum (BMI <48 kg/ dumping syndrome, m2) anastomotic ulcers, nutrition 150 cm jejunum (BMI >48 kg/ and vitamin (B12,D) m2) deficiencies, internal hernias Omega loop mini gastric Primary bariatric (restrictive Long gastric pouch (restrictive 70–80% at 2 yrs 0.1 Biliary reflux, anastomotic bypass (MGBP) and malabsorptive) part), jejunal omega loop of ulcer, dysplasia 150–200 cm (malabsorptive part) Bilio-pancreatic diversion Primary bariatric (restrictive Gastric pouch (150–400 ml) 70–80% at 2 yrs 1.1 Dumping syndrome, (BPD) and malabsorptive) Absorptive ‘common’ limb anastomotic ulcers, vitamin (60 cm proximal to terminal deficiency, bone ileum) demineralization, protein deficiency, diarrhoea, foul smelling stool, anaemia, internal hernias more frequent Bilio-pancreatic diversion Primary bariatric (mildly Sleeve gastrectomy 75–80% at 2 yrs 1.1 Similar to BPD but less with duodenal switch restrictive and mainly Absorptive ‘common’ limb dumping syndrome and (BPD-DS) malabsorptive) (100 cm proximal to terminal anastomotic ulcers, severe ileum) protein deficiency Diarrhoea (8×/day) Single anastomosis Primary bariatric (restrictive Duodeno-ileal bypass 75–80% at 2 yrs, 90% at 5 yrs Less diarrhoea than BPD-DS, duodeno-ileostomy and significantly ‘common’ limb 3 m protein deficiency (SADI) malabsorptive) 18 E.P. Weledji / International Journal of Surgery Open 5 (2016) 11–19 a higher risk of complication than the original procedure, revi- Guarantor sions must be performed by experienced surgeons. Prof Marcelin Ngowe Ngowe, Dean, Faculty of Health Sciences, University of Buea. 9. Outcome of bariatric surgery

Research registration UIN Metabolic (bariatric) surgery results in better glucose control than medical therapy and overwhelmingly leads to disease remission This was not required in this review article. [7–10]. Results at 2 years showed DM remission of 0% in a medical cohort, 75% in the gastric bypass group and 95% for the biliopancreatic diversion group [78]. Operative intervention is more Appendix: Supplementary material effective than conservative measures at present in treatment of obesity, resolution of co-morbidities and cost effectiveness. At 1 year Supplementary data to this article can be found online at the mean total % weight loss from all surgical approaches is 20– doi:10.1016/j.ijso.2016.09.004. 21.6% and 1.4–5.5% from non-surgical approaches. At 2 years there is 16–28% weight loss following surgery but weight gain of 0.1– References 0.5% with non-surgical approaches [80]. 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