The American Society for Metabolic and Bariatric Surgery (ASMBS) Pediatric Committee has recently updated their guidelines [3]. Adolescents with class II obesity and a diagnosed co-morbidity or with class III obesity should be considered for MBS [14].

Pratt et al. recently recommended treatment teams to conduct a thorough pre-operative evaluation including metabolic profiling but also to provide sufficient education about the surgical interventions and the postoperative lifestyle changes that will be necessary [14].

In Europe, indications for MBS in morbidly obese adolescents vary between countries. Nevertheless, the European Association for the Study of Obesity and the European Chapter of the International Federation for the Surgery of Obesity have agreed upon interdisciplinary European guidelines on MBS in adolescents in 2013 [15]. According to these guidelines, bariatric surgery can be considered in patients

Moreover, bariatric surgery can even be considered in patients with genetic syndromes such as Prader–Willi syndrome, but only after careful consideration by an expert medical, pediatric, and surgical team [15].

The German guideline published by the German Society for General and Visceral Surgery describe a BMI ≥ 35 kg/m² and at least one diagnosed somatic and/or psychosocial comorbidity as indication for bariatric surgery in children and adolescents. In patients with a BMI ≥ 50 kg/m², surgery can be considered even without any comorbidity. The patient, however, should have reached 95% of the predicted final height or Tanner stage IV. Before surgery, the adolescents should have undergone at least 6 months of unsuccessful conservative interdisciplinary lifestyle intervention programs [16].

Exclusion criteria for bariatric surgery in adolescents include:

• Severe psychiatric disorders (unstable psychosis, borderline personality, severe depression and personality disorders, active suicidality) and diagnosed eating disorders;
• Alcohol and/or drug abuse;
• Pregnancy (present or planned within 18 months after surgery);
• Inability of the patient to participate in a long-term interdisciplinary follow-up at the obesity center.

Immediately preoperatively, most multidisciplinary bariatric surgery programs nowadays recommend a protein-rich liquid diet to induce weight loss and decrease the mass of the liver size. Such conditioning improves surgical safety, operative times, and intraoperative blood loss [12].

Moreover, psychologists should examine the adolescents’ readiness and suitability for bariatric surgery. Amongst others, motivation, adherence, and the ability to understand pre- and postoperative requirements should be assessed [17].

When dealing with obese adolescents who may qualify for bariatric surgery, the role of the parents should not be underestimated because parental attitudes towards the weight status of their children may pose significant barriers to their consideration of treatment options [18]. It has been shown that most parents of overweight children fail to recognize that their child has a weight problem [19,20]. Moreover, in their telephone survey, Singh and Chernoguz found that only half of the parents with obese children concerned for their child’s future health would consider metabolic surgery, and most parents who would consider metabolic surgery would wait until their child was over age 18. However, provider counseling seems to significantly increase parents’ likelihood to consider bariatric surgery [18]. The authors concluded that “more detailed provider education on the current state of bariatric surgery in the treatment of severe adolescent obesity is necessary.” [18].

Despite a recent increase in the number of these surgeries, adolescents still constitute only a very small proportion of patients undergoing bariatric procedures. In the United States, adolescents constitute only 0.1% of all patients subjected to metabolic and bariatric procedures [21]. As a consequence, and according to the present guidelines, MBS should be performed in high-volume centers specialized in the medical and surgical treatment of morbid obesity at any age. Thus, it seems highly advisable for pediatric surgeons to join a high-volume center for adult bariatric surgery. In the US, the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) requires for adolescent bariatric surgery that a children’s hospital conducting fewer than 25 stapling cases per year invites an MBSAQIP-verified bariatric surgeon on each case [14].

Pathophysiologically, a fundamental distinction is made between the so-called restrictive versus the malabsorptive procedures. Restrictive procedures “simply” tighten the stomach, for example, by placing an adjustable band around the fundus (laparoscopic adjustable gastric banding, LAGB). This maneuver creates a pouch and a small channel into the remaining stomach. The volume of food passing through the band may be adjusted by changing the diameter of the band. The continuity of the gastrointestinal tract remains intact.

The Roux-Y gastric bypass (RYGB) remains the “gold standard” of all malabsorptive procedures. Technically, the stomach is resected close to the gastroesophageal junction, leaving only a small pouch of approximately 20 mL. A loop of the small bowel is anastomosed to this gastric pouch (alimentary loop), while the rest of the stomach, duodenum, and the adjoining proximal small intestinal loops are initially excluded from the food route (biliodigestive loop). Further distally (100–170 cm), both loops are joined (common channel), allowing the absorption of food.

Sleeve gastrectomy (LSG, Laparoscopic Sleeve Gastrectomy) may serve both principles. Basically, the stomach is resected longitudinally, leaving a “restricted” volume of approx. 50–100 mL. This procedure was first recommended by the authors as a “stand-alone” technique for young adolescents in 2008 [22]. Metabolically, it is assumed that resection of the gastric fundus also extensively removes ghrelin production. Since ghrelin induces feelings of hunger in the central nervous system (arcuate nucleus), the removal of ghrelin-producing cells induces changes in the eating behavior [23,24,25]. Valid studies have shown that it is almost as effective as RYGB in inducing weight loss and improving co-morbidities [26]. Thus, LSG has gained general acceptance and has become the most commonly performed MBS procedure in adolescents [3].