Use of Sleeve Gastrectomy in Adolescents and Young Adults with Severe Obesity

Abstract

Purpose of review

The prevalence of pediatric obesity and its associated complications is increasing around the world. Treatment of obesity is challenging, and metabolic and bariatric surgery (MBS) is currently the most effective treatment for this condition. At this time, vertical sleeve gastrectomy (VSG) is the most commonly performed bariatric procedure in adolescents. However, knowledge regarding the efficacy, safety and durability of VSG in adolescents is still evolving. This review summarizes the most recent updates in the field of MBS particularly VSG in adolescents.

Recent findings

MBS is recommended to treat moderate to severe obesity, especially when complicated by comorbidities. The use of VSG for weight loss is increasing among adolescents and produces similar weight loss at five years in both adolescents and adults. The physiologic mechanisms causing weight loss after VSG are multifactorial and still being investigated. The complication rate after VSG ranges between 0–17.5 %.

Summary

VSG appears to be a safe and effective procedure in adolescents. However, it continues to be underutilized despite the increasing prevalence of moderate to severe obesity in adolescents. It is thus important to educate providers regarding its benefits and safety profile.

Introduction

Obesity is a chronic, relapsing neurobehavioral disease, characterized by dysfunctional adipose tissue accumulation that leads to adverse metabolic, biomechanical, and psychosocial sequelae. Because childhood obesity tracks into adult obesity (1, 2), and children with obesity are at a higher risk of early onset of several comorbidities [depression, type 2 diabetes (T2D), hypertension (HTN), obstructive sleep apnea (OSA), nonalcoholic steatohepatitis (NASH)], early aggressive treatment is necessary to induce weight loss and prevent and/or treat these comorbidities. Currently, the most effective strategy for weight loss is metabolic and bariatric surgery (MBS). According to the American Society for Metabolic and Bariatric Surgery (ASMBS), MBS is indicated in adolescents with moderate to severe obesity (3), particularly with comorbidities. In agreement with this, the American Academy of Pediatrics (AAP) recommends that pediatricians follow the 2019 practice level measures for managing severe obesity, and by understanding the efficacy, hazards, advantages, and long-term health consequences of MBS, provide a family-oriented decision-making approach to their patients (4). MBS has proven to achieve substantial and sustained weight loss and improvement/remission of major comorbidities (5–18). Moreover, a recent study showed that adults and adolescents have the same percent weight loss at five years following MBS (only Roux-en-Y gastric bypass (RYGB) was reported in this study, as this was the most commonly performed MBS until a decade ago) (19). Data regarding the short- and long-term benefits and safety of VSG in adolescents are still evolving. In this review, we summarize the latest studies in VSG.

Disease Burden

Nearly 5 % of all adolescents and children in the United States have severe obesity, and the risk is highest in African American, Hispanic and Native American youth (20–24). Data indicate that severe pediatric obesity has a high probability of progressing into adulthood (6, 25, 26), and obesity has a cumulative health-deteriorating effect, making it essential to treat obesity sooner (20). Moreover, adolescents with moderate to severe obesity suffer from comorbidities seen in adults- type 2 Diabetes (T2D) (27), non-alcoholic liver disease (NAFLD), dyslipidemia (DL) (28), early-onset atherosclerosis (overt or subclinical) (29), hypertension (HTN) (30), obstructive sleep apnea (OSA) (31), and polycystic ovary syndrome (PCOS) (32, 33). Adolescents with obesity are also at a markedly increased risk of psychological disorders (34).

Current Non-Surgical Therapeutic Options for Pediatric Obesity

Evidence suggests that behavior-modifying interventions of moderate intensity (26 or more hours of provider interaction) may decrease the body mass index (BMI) z-score by 0.2 kg/m² in children with mild obesity (35–37). While potent anti-obesity drugs are becoming available for adults (such as the newer glucagon like peptide -1 (GLP-1) analogs), FDA-approved medications are still scarce in youth (20). The only FDA approved medications include orlistat in children and phentermine for adolescents 16 years and older (33). Pharmacological options in youth are therefore limited.

Metabolic and Bariatric Surgery as a Therapeutic Option for Pediatric Obesity

Commonly performed MBS procedures are shown in Table 1 (20, 38–41). In adolescents with severe obesity, MBS is superior to other therapeutic approaches in achieving efficient and durable BMI reduction and remission of comorbidities, although there is significant individual variability in the magnitude of weight loss after surgery (42–44). Despite its efficacy, MBS remains significantly underutilized in children and adolescents (45, 46). One study estimated that only 0.1% of qualifying adolescents in five large pediatric surgical centers get MBS (46).

Table 1.

Different Types of Bariatric Surgery and Their Characteristics

	Vertical Sleeve Gastrectomy (VSG)	Roux-en-Y Gastric Bypass (RYGB)	Adjustable Gastric Banding (AGB)
Mechanism	Most of the greater curvature of the stomach is resected (gastric volume reduced by ~ 80%) (38).	Malabsorptive and restrictive. A small (< 30 mL) proximal gastric pouch is separated from the distal stomach and anastomosed to a Roux-limb of small bowel.	Purely restrictive procedure that compartmentalizes the proximal stomach by inserting a tight, adjustable prosthetic band through the posterior esophago-gastric tunnel
Advantages	Less intricate procedure and lower risk for micronutrient deficits, compared to RYGB. Greater weight loss than AGB.	Considered gold standard for surgical management of severe obesity regardless of age (20, 39, 40). Long-term outcomes in relation to weight loss and comorbidity improvement are well-known.	Simple procedure
Drawbacks	Long-term weight loss may be less than that achieved from RYGB Long-term data in adolescents evolving	Higher risk for nutritional deficiencies compared with VSG especially iron deficiency;	Foreign body complications (41). Not FDA approved for patients under 18 years of age
Outcomes	Weight loss and improvement of comorbidities.	Weight loss and improvement of comorbidities.	Weight loss and improvement of comorbidities.

VSG was introduced as a “pilot” bariatric surgery for patients with extreme obesity (BMI > 50 kg/m2) (47), only to gain worldwide popularity as a standalone procedure, increasing from 4.5% of all MBS in 2008 to the most commonly used procedure in the United States in 2015 for adolescents and adults (48–50).

• Eligibility:

  MBS, including VSG, is indicated in adolescents with (i) BMI ≥ 35 kg/m² or ≥ 120% of the 95th percentile for sex and age (class II obesity) with the presence of at least one comorbidity, or (ii) BMI ≥ 40 kg/m² or ≥ 140% of the 95th percentile (class III obesity) with/without comorbidity (3). In addition to BMI and comorbidity status, maturity of the patient (physiologic, psychological, and developmental) is a consideration (25). Selecting surgical candidates entails joint decision-making that includes the patient (and family) and the multidisciplinary medical team.

• Contraindications:

  According to ASMBS 2018 Guidelines, Metabolic and Bariatric Surgery (MBS) (including VSG) is contraindicated in adolescents in the following scenarios:

  • Obesity that can be medically treated
  • Untreated or poorly controlled substance abuse within the past year
  • Existing or intended future pregnancy within 12 to 18 months of the planned surgical procedure
  • Current history of eating disorder
  • Medical, psychiatric, psychosocial, or cognitive hindrance to complying with postsurgical recommendations and required lifestyle modifications (3).

• Preoperative Assessment:

  Adolescent VSG should be offered by a multidisciplinary team with expertise in such surgery. The healthcare team should include, but not be limited to, an experienced bariatric surgeon, a pediatric obesity medicine expert, dietician, and pediatric psychologist or psychiatrist (51–53).

  Adolescents and their caregivers should receive education around healthy lifestyle and behaviors, the expected changes after surgery, the need for lifelong vitamin supplementation and monitoring, particularly around pregnancy, alterations in bone health, and preparation for major transitions such as moving away from home.

• Postoperative management

  Adolescents usually stay in the hospital from one to three days after VSG (54, 55). After VSG, patients gradually advance through several dietary stages - from high-protein shakes to ingestion of larger volumes and more solid foods over the first six post-operative months. Frequent follow up with one of the team members is recommended in the first three to six months. Management may need adjustment if inadequate weight loss, weight regain, micronutrient deficiencies or dietary intolerance occur (56). Table 2 describes the long-term postsurgical management (57, 58).

Table 2.

Postsurgical Management After Bariatric Surgery

Long Term Diet/Exercise Follow-Up	Nutritional Supplements	Annual Monitoring
30–60 minutes daily exercise Consume protein first at each meal (1 g/kg of ideal body weight) 3–4 portion-controlled, high-protein meals daily Minimize snacking Avoid fat and carbohydrate dense foods, and sugary drinks to avoid malabsorption and dumping Daily vitamin and mineral supplementation	Standard multivitamin with folate and iron, or prenatal vitamin if female (pregnancy) Vitamin B12: 500 micrograms orally/sublingually daily, or 1000 micrograms intramuscularly monthly Calcium (as calcium citrate) 1200 mg to 1500 mg daily with 800 to 1000 IU of vitamin D In case of severe postoperative emesis, vitamin B1 (thiamine) deficiency can develop quickly (57). Prophylactic vitamin B1 supplementation (50 mg orally daily) during the first 6 months postoperatively (58).	Complete blood count with differential Serum iron, ferritin, folate, vitamin B12, Thiamine Liver Function tests Calcium, 25-hydroxyvitamin D, parathyroid hormone Dual-energy x-ray absorptiometry (DXA) scan to monitor bone density: (optional and may not be needed in patients with good nutritional status and not high risk) (58).

Genetic and Other Predisposition to Success of Surgery

Like all treatments of obesity, the magnitude of weight loss after VSG is also influenced by genetics. During a 2-year post-VSG follow-up in 1014 patients with severe obesity, Cooiman et al. found that those harboring melanocortin 4 receptor (MC4R) mutations had lower percent total body weight loss relative to patients lacking a molecular diagnosis (59). Furthermore, a longer follow-up (6-year) study by Li Y et al. patients with obesity and monogenic mutations had lower weight loss after MBS (60). Some data suggest that MBS did not perform as well in adolescents with Prader-Willi Syndrome (PWS), as compared to children without syndromic obesity (61). On the other hand, a case-control study by Alqahtani et al. which studied 24 children and adolescents with and without PWS showed that VSG led to similar weight loss in both groups within the first 12 months (62). Hence the data on the weight loss benefit of VSG with syndromic obesity are still conflicting. In a study by Bretault et al. in adolescents with hypothalamic obesity associated with craniopharyngioma, RYGB was better at sustaining effective long-term weight reduction than VSG (63–65).

Pregnancy and Effects on the Next Generation

A study by B-Aricha-Tamir et al. found that in paired pregnancies (same women before and after MBS), rates of hypertension and diabetes mellitus during pregnancy decreased after MBS. Also, birthweight of offspring was lower after MBS leading to lower rates of cesarean delivery or shoulder dystocia after surgery (66). The metabolic outcomes of fetuses born after MBS are improved compared to their siblings born before MBS (67).

Physiological Changes After VSG

There are numerous changes that occur after VSG that may contribute to weight loss and its metabolic benefits. Besides the mechanical restriction caused by the decreased volume of the stomach, VSG is associated with (i) a reduction in ghrelin levels (orexigenic hormone) (68, 69), (ii) a nutrient-driven massive increase in serum glucagon-like peptide-1 (GLP-1), an incretin (70–75), (iii) an increase in peptide YY (PYY) (iv) an increase in postprandial total bile acids (76) (77) and (v) changes in the gut microbiome. Decreased ghrelin levels following VSG (22,28) can be attributed to the reduction in ghrelin-secreting cells from the gastric antrum (resected during VSG). The rise in GLP-1 happens acutely (days) after surgery and is thought to promote weight loss and improve glycemia early on by stimulating insulin release while inhibiting glucagon secretion, blocking hepatic gluconeogenesis, and decreasing food intake (16,17). Peptide YY (PYY), which plays a role in the central regulation of appetite and food intake, also increases post-prandially acutely and long term (20,21) following VSG and may contribute to a decrease in food intake (22). Bile acids play a pivotal role in regulating glucose, lipid and energy metabolism, and much of the benefits of VSG were mitigated in a mouse model when the bile acid receptor was knocked out (78). Gut microbiota play a crucial role in host metabolism (energy biogenesis, biosynthesis of steroids and bile acid metabolism). VSG resulted in overgrowth of Bacteroidetes phyla which is relatively low in individuals with obesity (79).

Outcomes

Long-term outcome data after VSG in adolescents is still evolving with current studies having limited follow-up (less than 5 years) and significant loss-to-follow up (80, 81).

Weight Loss:

In the Teen longitudinal assessments of bariatric surgery (Teen-LABS) study which includes both RYGB and VSG patients, an average weight loss of 27% was observed at three years (82). A recent study evaluating percent weight loss up to four years after VSG showed greater benefit in adolescents than adults, suggesting greater gains from early surgery. Moreover, unlike the adult cohort in this study, adolescents did not show greater weight loss after RYGB as compared to VSG. This is encouraging that a simpler procedure (VSG) than RYGB can produce similar weight loss in adolescents (83). According to a Nationwide Retrospective analysis conducted in 2017, there was no difference in weight loss and obesity-related conditions remission rates based on gender or race (84). Moreover, the operative technique, particularly the distance between the resection margin and the pylorus is associated with better and sustained weight loss after VSG (85).

• Endocrine: A cohort of 52 adolescents was followed for three years following VSG, and demonstrated an 88% remission rate of T2D (86) Another study showed similar results with 87% of adolescents having resolution of T2D after MBS (both VSG and RYGB) compared to only 54% of adults (83). Surgical intervention is certainly more effective than pharmacotherapy in treating T2D in adolescents with severe obesity (87). In a recent study, researchers found that two weeks after MBS (RYGB/VSG) insulin resistance decreased and β-cell function improved due to an increase in GLP-1 levels (88).

• Cardiovascular: The Teen-LABS cohort showed a 74% remission rate for hypertension and 66% for dyslipidemia following surgery (17). Even in those without complete remission, there was a dose reduction in hypertensive pharmacotherapy in almost 59% of subjects who underwent VSG (89). The resolution of HTN after VSG is greater in adolescents than adults, again demonstrating the greater metabolic fluidity and greater resolution of obesity related comorbidities when VSG is performed at a younger age (83)

• Hepatic: Teen-LABS study showed that VSG improves NAFLD in around 85% of patients (3). A small controlled study of adolescents with NASH (steatosis to fibrosis) demonstrated benefit from VSG as compared to no improvements with lifestyle interventions (REF).

• Psychosocial Well Being and Mental Health: Quality of life has been demonstrated to improve acutely after VSG (82). A recent meta-analysis in adolescents with severe obesity showed that bariatric surgery was associated with sustained improvement in quality of life (QoL) (90).

  Patients with severe anxiety/depression present before surgery maybe at an increased risk for postoperative mental health deterioration (91). While data in adults after RYGB suggest a mild increase in self-injurious behavior, there are no data available in adolescents following VSG (92).

Complications

The main complications following VSG are insufficient weight reduction, weight regain, or severe GERD (89). Surgical complications are rare, mostly minor (15%), and occur acutely in the postoperative stage (25, 82, 93). The re-operative rate prior to hospital discharge is similar in both pediatric and adult populations (2.7% in Teen-LABS cohort) [143]. Complications can be intraoperative (rare), occur in the acute post-operative phase (up to 30 days postoperatively), or long-term.

• Intraoperative Complications (~1%): Risks are comparable to those of other laparoscopic abdominal operations. Nonetheless, comorbidities that accompany obesity increase the risk of complications and the risk increases with higher BMI (94). These include:

  • Anesthesia-related events
  • Injury to bowels, spleen or liver
  • Damage to major vasculature (e.g. inferior vena cava, portal vein)
  • Bowel ischemia
• Acute Postoperative Complications:

  • Anastomotic leak is the most common and usually happens within one week postoperatively. The classic alarming sign is unexplained tachycardia (> 120 bpm).
  • Nausea, vomiting and dehydration
  • Surgical site infection
  • Rare complications, mostly in adults, include myocardial infarction, hemorrhage and deep vein thrombosis
• Long Term Complications:

  • Internal hernias/marginal ulcers are less common with VSG than RYGB
  • Micronutrient deficiencies more common after RYGB but may also occur after VSG (especially folate and iron)
  • Weight regain after VSG is possible as with other bariatric procedures. Regular monitoring with the obesity medicine physician is highly encouraged.
  • Bone health –Recent data in adolescents after VSG suggest adverse areal bone density and bone microarchitectural changes, but no change in bone strength estimates one year after VSG (95). Longer follow-up studies are needed to better inform us of bone outcomes following VSG.

Conclusion

Obesity is a multifactorial disease, , instigated by the interplay of genetics, environment, and metabolic pre-wiring (96). Adolescents with obesity suffer from substantial stigma and are frequently held responsible for their disease (46, 96, 97). MBS is effective in treating severe obesity in adolescents and should be considered when appropriate under the auspice of a multidisciplinary team while assessing the risk benefit ratio (3, 98). VSG has become the most widely used and recommended surgery in adolescents with severe obesity, and has a better effect on weight loss and comorbidity resolution when done at a younger age. It is critical to supplement post-operative patients with lifelong vitamins, and routine monitoring by their bariatric team is highly encouraged. More long-term studies evaluating the outcomes of VSG in adolescents are needed.

Key Points.

• VSG is successful and safe in adolescents and may have greater benefits than seen in adults.

• VSG significantly improves cardiovascular and endocrine risk factors (dyslipidemia, hypertension, insulin resistance, T2D).

• Long-term vitamin supplementation and follow up with the bariatric team is recommended after VSG.