85th percentilea (overweight)
95th percentilea (obesity)
99th percentileb (extreme obesity)
120 % of 95th percentilec (severe or class II)
140 % of 95th percentilec (class III)
Selected BMI for age percentile curves for male. At approximately age 18, the 85th percentile correlates with adult overweight, 95th percentile with adult class I obesity, 99th or 120 % of 95th percentile with adult class II obesity, and 140 % of 95th percentile with adult class III obesity. Sources—50th, 85th, and 95th percentiles: CDC. 99th percentile: Barlow SE et al. Pediatrics 2007.
Most centers define candidacy for operative intervention as either a BMI of >40 kg/m2 alone or a BMI of >35 kg/m2 with major comorbidities. About 3 % of US adolescents meet these criteria. Skeletal and physiologic maturity is widely accepted as a prerequisite to surgery. Age (13 years for girls and 15 years for boys) is often used as a surrogate. Comorbid medical and psychiatric conditions should be well stabilized prior to surgery. A treatment algorithm is shown in Fig. 47.2.
Treatment algorithm for patients referred to a multidisciplinary pediatric obesity clinic.
In order to achieve both superior safety and outcomes, there must be commitment to a team approach and close follow-up by both a multidisciplinary weight loss team and the patient and the patient’s family. Adolescent candidates for weight loss procedures, in comparison to adults, face the added challenges of psychological immaturity, peer pressure, poor compliance, a propensity for risk-taking behaviors, and possible loss to follow up when beginning college or a career. A 6-month trial of behavioral interventions should be attempted prior to planning an operation, during which compliance and the family and social environment should be evaluated.
Assent of the patient younger than 18 years and a well-informed consent from the parents are necessary. It must be very clear that the family possesses a thorough understanding of risks and realistic expectations of outcomes and the work ahead, and that adequate family and community resources and support are available prior to scheduling an operation.
Patient Positioning and Room Setup
Setup is similar to sleeve gastrectomy and gastric bypass. The patient should be placed in reverse Trendelenburg position in order to visualize the upper abdomen. A footplate is needed to keep the patient from gradually sliding caudally down the table. In all bariatric procedures, padding of all prominences to protect against the skin, vessel, and nerve injury takes on special importance. Even on well-padded surfaces, patients with a BMI upward of 50 are at risk of rhabdomyolysis with a long procedure.
Deep vein thrombosis prophylaxis should consist of pre- and postoperative enoxaparin at a prophylactic dose (e.g., 40 mg subcutaneous for individuals with a BMI ≤50 kg/m2 and 60 mg for individuals with a BMI ≥50 kg/m2) and sequential compression devices placed on both calves prior to induction of anesthesia. Antibiotic prophylaxis against wound infection and covering skin flora are given prior to incision.
The surgeon stands on the right of the patient with the first assistant directly across and both patient arms out. Some surgeons prefer to place both of the patient’s legs in stirrups and work alternatively from the right and from between the patient’s legs to avoid working at angles.
Trocar Position, Instrumentation, and Technique
Roux-en-Y Gastric Bypass
Roux-en-Y gastric bypass (RYGB) was first reported in 1975 and is the most common procedure performed in adolescents, and nearly all are performed laparoscopically. This is consequently the best-studied procedure in adolescents. RYGB results in a reduced-capacity stomach and diversion of ingested nutrients, as well as removal of parietal cells responsible for the production of ghrelin. A small stomach pouch is created and a Roux limb is brought up at about 50 cm from the ligament of Treitz in order to bypass biliopancreatic secretions and to prevent significant caloric absorption until the common limb is reached (Fig. 47.3). The laparoscopic approach to RYGB is currently the standard in all abdomens without thick adhesions. We begin with construction of the pouch; however the Roux limb can be created first.
Roux-en-Y gastric bypass surgical anatomy . From Naik RD, Choksi YA, Vaezi MF. Consequences of bariatric surgery on esophageal function in health and disease. Nature Reviews Gastroenterology and Hepatology 2016;13:111–119. Reprinted with permission from Nature Publishing Group.
A 12-mm optical-entry trocar is placed in a supraumbilical position slightly left of midline, loaded on a 10-mm zero-angle scope. The abdomen is insufflated to 10 mmHg. A 30-degree 10-mm scope is used for the procedure.
Under direct visualization , two 5-mm ports are placed, triangulated with the xiphoid on both sides of the abdomen to allow the surgeon to work from any angle and to receive support from a first or second assistant.
A Nathanson liver retractor is placed through a 5-mm subxiphoid incision made with a 5-mm trocar, the liver is elevated to expose the lesser curvature of the stomach, and the retractor is attached to a fixed post.
A Tru-Cut biopsy of the liver is taken to test for Non-alcoholic fatty liver disease (NAFLD) .
Gastric pouch creation begins with dissection of the left crus to provide access to the left side of the cardia.
The hepatogastric ligament is then taken down with an EnSeal® (Ethicon) or Harmonic Ace Shears (Ethicon) about 4 cm down from the gastroesophageal junction (Fig. 47.4).
Pitfall—Care is taken to preserve the first two gastric branches of the left gastric artery (to prevent pouch ischemia) and, if present, a replaced left hepatic artery. Be alert for an accessory left hepatic artery as coming partially across one can lead to significant bleeding.
The hepatogastric ligament is carefully opened while evaluating for replaced or accessory left gastric vessels.
A retrogastric tunnel is bluntly dissected beginning at the lesser curvature, entering the lesser sac, separating the pancreas and other tissues from the back wall of the stomach to allow for stapling, until the dissecting instrument can be seen at the previously created opening in the left phrenoesophageal membrane.
A 45-mm laparoscopic stapler (with 3.5-mm blue-load staples) is fired horizontally starting at the lesser curve about 4 cm below the GE junction. The horizontal staple line should be approximately 4 cm long.
Pearl—This can be measured with an open grasper, which is approximately 2 cm from tip to tip.
A 32-Fr blunt-end bougie or Ewald tube is placed at the level of the horizontal staple line for sizing of the gastric pouch. The goal is a 30–50-cc pouch, about the size of an egg.
Subsequent vertical firings complete the pouch. Staple-line bleeding can be controlled with surgical clips.
Pitfall—Care is taken to provide clearance from the gastroesophageal junction by angling the final staple load slightly toward the fundus.
Pitfall—Care is taken to keep the stomach taut with a grasper and to not let the back wall of the stomach fold so that four layers of the stomach wall are being crossed.
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50 cm of the small bowel is measured distal to the ligament of Treitz with hand-over-hand technique.
Pearl—Place a piece of white tape on one grasper 10 cm proximal to the tip to more accurately measure the length of the bowel.
100 cm are further measured distally along the jejunum. This distance may vary depending on whether BMI is greater or less than 50 kg/m2. A white load (3.1-mm staples) is used to divide the jejunum. An absorbable stitch is placed for identification on the end that will be anastomosed to the gastric pouch.
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