Sonographic Evaluation of Visceral Fat After Bariatric Surgery
Condition: Morbid Obesity
MeSH terms: Obesity, Morbid
Study type: Observational

Summary: 
      Excess visceral fat is a key factor in the development of metabolic syndrome associated with
      obesity. After bariatric surgery, patients experience weight loss accompanied by a decrease
      in the amount of total body fat. It is unclear how the different surgical procedures vary in
      their effect on the visceral and subcutaneous fat change. Ultrasonography (US) is an
      effective, efficient method in assessing this metabolically active layer of fat even when
      compared with gold standard techniques such as computed tomography and magnetic resonance
      imaging. Only a few studies managed to show the actual decrease in the visceral fat layer
      after these kinds of surgeries. The aim is to compare by ultrasound evaluation the extent of
      fat layers reduction after laparoscopic adjustable gastric banding (LAGB), laparoscopic
      sleeve gastrectomy (LSG) and laparoscopic roux-en-y gastric bypass (LRYGB). The hypothesis is
      that the sleeve gastrectomy and gastric bypass being not only a restrictive procedure but
      also a malabsorptive procedure will have the best results in decreasing the amount of
      visceral fat.
    

Detailed description: 
      excess visceral fat is a key factor in the development of metabolic syndrome associated with
      obesity. After bariatric surgery, patients experience weight loss accompanied by a decrease
      in the amount of total body fat. It is unclear how the different surgical procedures vary in
      their effect in reducing the amount of the visceral fat layer . Ultrasonography (US) is an
      effective, efficient method in assessing this metabolically active layer of fat even when
      compared with gold standard techniques such as computed tomography and magnetic resonance
      imaging. Only a few studies managed to show the actual decrease in the visceral fat layer
      after these kinds of bariatric surgeries. The aim is to compare by ultrasound evaluation the
      extent of fat layers reduction after laparoscopic adjustable gastric banding (LAGB),
      laparoscopic sleeve gastrectomy (LSG) and laparoscopic roux-en-y gastric bypass (LRYGB).

      Visceral fat (VF) will be defined as the depth, in centimeters, from the rectus abdominis
      muscle to the aorta; and subcutaneous fat (SCF) defined as the depth, in centimeters, from
      the skin to the rectus abdominis muscle. Results will be compared with anthropometric
      measures as weight and waist circumference as well as laboratory results to try and find
      correlation between sonographic improvement and anthropometric and laboratory improvement.

      The hypothesis is that the sleeve gastrectomy and gastric bypass being not only a restrictive
      procedure but also a malabsorptive procedure will have the best results in decreasing the
      amount of visceral fat.
    

Observational model: Case-Only
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Morbid obese patients admitted electively to our surgery ward after receiving detailed
        explanation about each type of surgery and after independently choosing to undergo either a
        laparoscopic adjustable gastric banding, a sleeve gastrectomy or a gatsric bypass will be
        offered to participate in the study.

        The patients must meet criteria for being morbid obese as defined as a body mass index
        greater than 40 kg/meter*meter or a body mass index greater than 35 with relevant
        comorbidities. The patients must meet other inclusion and exclusion criteria as defined
        below.

        The patients will be offered to participate in the study regardless of their gender or
        race.
      
Keywords: morbid obesity; intra-abdominal visceral fat; gastric bypass; sleeve gastrectomy; gastric banding; visceral fat