Biliopancreatic diversion (BPD) is an obesity surgery procedure whose effect, as a purely malabsorptive procedure (procedure that results in poorer utilization of food), is only partially based on a reduction in the amount of food. The main effect of the procedure is primarily to delay the mixing of the food pulp with the digestive enzymes and bile acid. In particular, the late mixing prevents the fat contained in the food from being fully digested. Biliopancreatic diversion may be offered for obesity with a BMI ≥ 35 kg/m2 or greater with one or more obesity-associated comorbidities when conservative therapy has been exhausted. Biliopancreatic diversion can also be combined with restrictive surgical procedures so that the effect of the procedure can be improved.
Indications (areas of application) for bariatric surgery [according to S3 guideline: Surgery for obesity and metabolic diseases, see below]
- In patients with a BMI ≥ 40 kg/m2 without concomitant diseases and without contraindications, bariatric surgery is indicated after exhaustion of conservative therapy after comprehensive education.
- Patients with a BMI ≥ 35 kg/m2 with one or more obesity-associated comorbidities such as type 2 diabetes mellitus, heart failure, hyperlipidemia, arterial hypertension, coronary artery disease (CAD), Nephropathy, obstructive sleep apnea syndrome (OSAS), obesity hypoventilation syndrome, Pickwick syndrome, nonalcoholic fatty liver (NAFLD), or nonalcoholic fatty liver hepatitis (NASH), Pseudotumor cerebri, gastroesophageal reflux disease (GERD), bronchial asthma, chronic venous insufficiency (CVI), urinary incontinence, immobilizing joint disease, fertility limitations, or polycystic ovary syndrome (PCO syndromeM) should be offered bariatric surgery when conservative therapy is exhausted.
- In certain circumstances, a primary indication for bariatric surgery may be made without a prior attempt at conservative therapy. The primary indication may be given when any of the following conditions exist: in patients.
- With a BMI ≥ 50 kg/m2.
- In whom a conservative therapy attempt was classified by the multidisciplinary team as not promising or hopeless.
- With particular severity of concomitant and secondary diseases that do not allow postponement of a surgical intervention.
Contraindications
- Unstable psychopathological conditions
- Untreated bulimia nervosa
- Active substance dependence
- Poor general health
- Lack of indication – should obesity be caused by a disease (e.g., hypothyroidism, Conn syndrome (primary hyperaldosteronism, PH), Cushing’s disease, pheochromocytoma)
Before surgery
Before biliopancreatic diversion, a detailed physical examination and a comprehensive medical history of the patient must be performed. Exclusion of diseases that may be considered the cause of the presenting obesity must be performed. Thus, hypothyroidism (hypothyroidism), adrenocortical hyperfunction (hypercorticism/hypercortisolism; Cushing’s disease), psychological diseases, and disorders must not be present.
The surgical procedure
The basic principle of biliopancreatic diversion is based, among other things, on reducing the capacity of the stomach. The target volume of the stomach after the procedure is usually 200-300 ml. In contrast to tubular stomach surgery, biliopancreatic diversion is partially reversible due to leaving the antrum (mouth of the stomach) in place. The procedure involves an exclusively functional shortening of the small intestine. The jejunum (middle part of the small intestine) is cut at the transition into the colon and anastomosed (surgically connected) to the gastric pouch (“artificially miniaturized stomach”). A special feature of the procedure is that the digestive enzymes are introduced via a so-called biliodigestive loop into the common channel (common digestive tract), where the digestive enzymes from bile and pancreatic secretion (secretion of the pancreas) mix with the food.This leads to malassimilation (disturbance of predigestion in the stomach, of enzymatic breakdown of food components (exocrine pancreatic insufficiency/disease of the pancreas associated with insufficient production of enzymes), of fat emulsification (e.g. bile acid deficiency in cholestasis/bile stasis) and of resorption or removal of the absorbed food; in this case fat. Fat, due to lack of enzymatic breakdown of the same. Furthermore, a permanent influence of the hunger hormone ghrelin (acronym for Growth Hormone Release Inducing; this is an appetite-stimulating hormone produced in the gastric mucosa) is prevented, since the fundus (stomach floor; dome-shaped curved part of the stomach, located to the left of the gastric inlet (cardia)) is left in place. Thus, the physiologic sensation of hunger is only slightly affected.
After surgery
During the first postoperative days, in addition to radiologic evaluation of the surgical result, the patient must undergo a slow diet buildup and mobilization. After bariatric surgery, both regular and long-term interdisciplinary follow-up is necessary. In addition to follow-up care by the surgeon, diabetologists and nutritionists in particular are essential to support and counsel the patient. The frequency of follow-up should be higher, especially in the first year after biliopancreatic diversion, because the complication rate is highest during this period. Studies have shown that patients who regularly participate in postoperative follow-up have a significantly higher weight loss than the comparison group that forgoes follow-up visits. Furthermore, participation in a support group is advised.
Potential complications
Early complications
- Thrombosis (vascular disease in which a blood clot (thrombus) forms in a vessel).
- Pulmonary embolism (occlusion of a pulmonary artery, due to an engulfed blood clot).
- Gastric perforation (rupture of the stomach)
Late complications
- Malabsorption – the procedure may cause deficiencies of various nutrients, such as vitamin B12. Occurring deficiencies can usually be treated or avoided by consistent substitution.
- Nephrolithiasis (kidney stones) – as a result of increased oxalate resorption kidney stones can occur.
- Anal diseases (diseases of the rectum/anus) – steatorrhea (increased excretion of fats) can lead to the development of anal diseases.
- Night blindness – vitamin A is necessary for the ability to see in the dark. As a result of the procedure, absorption in the gastrointestinal tract may be reduced.
