Does Size Matter? Correlation of Excised Gastric Specimen Size in Sleeve Gastrectomy to Postoperative Weight Loss and Comorbidities

Computed tomography-based gastric volumetry for morbid obesity to assess weight loss and fatty liver change

BACKGROUND/PURPOSE

Laparoscopic sleeve gastrectomy (LSG) is an effective treatment for patients with morbid obesity, but the optimal gastric volume (GV) for resection remains unclear. Accordingly, we aimed to determine the optimal percentage of excised stomach that could engender significant weight loss and improve fatty liver.

METHODS

This prospective study included 63 patients. Computed tomography (CT) scans were performed before and 1 year after LSG to evaluate the gastric lumen (GL) and GV. Specifically, the stomach was distended with effervescent powder, following water-contrast mixture (20:1) and assessed by three-dimensional reconstruction. The correlations of reduced gastric lumen/volume (RGL/RGV) with total body weight (BW) loss and liver-spleen density ratio (LSDR) changes were analyzed, and optimal RGL/RGV associated with significant BW and fatty liver changes were determined.

RESULTS

We noted a positive correlation between the percentage of RGV/RGL (%RGV/%RGL) and percentage of total weight loss (%TWL; r = 0.359, p = 0.004 and r = 0.271, p = 0.032). Furthermore, a %RGL value of >78.2% and %RGV value of >75.3% were associated with more significant BW loss than did limited excision (both p < 0.01). On the other hand, LSDR values increased significantly after LSG, corresponding to the improvement of fatty liver disease at %RGL and %RGV values of >59.1% and >56.4% (both p < 0.01), respectively.

CONCLUSION

%RGV and %RGL were determined to be factors affecting LSG outcomes. LSG engendered significantly more BW loss when %RGV was >75.3% and resulted in fatty liver disease improvement when %RGV was >56.4%.

Dietary supplements and bariatric surgery

Bariatric surgery or weight loss surgery has been in practice for achieving significant weight loss in patients who have failed to achieve weight loss after pharmacological interventions. The rising cases of obesity are a triggering factor for more bariatric surgeries worldwide. Interestingly, sustained weight loss achieved post-bariatric surgery offers metabolic advantages, and patients show improved glucose and lipid metabolisms. Bariatric surgery is directly linked to higher incidences of vitamin, mineral, and trace element deficiencies, thus making patients susceptible to anemia, osteoporosis, and cardiomyopathy. Reduced nutrient absorption capacity, dietary changes, dietary restriction, and altered gastrointestinal tract morphology are some reasons for nutritional deficiency observed in post-bariatric surgery procedures. Micro-and-macronutrient deficiency observed in patients during the postoperative phase requires continuous monitoring of nutritional parameters. Therefore, adequate multivitamin and mineral supplements become essential to prevent/overcome micronutrient deficiencies. Bariatric surgery also raises the risk of small for gestational age (SGA) babies. Hence, a 12 - 24 months gap is recommended between bariatric surgery and pregnancy to achieve desired weight loss targets. The topic of this review is the impact of bariatric surgery procedures on vitamin and mineral absorption and the role of dietary supplements in maintaining a healthy nutritional balance during the postoperative phase.

Role of the Autonomic Nervous System in Mechanism of Energy and Glucose Regulation Post Bariatric Surgery

Even though lifestyle changes are the mainstay approach to address obesity, Sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) are the most effective and durable treatments facing this pandemic and its associated metabolic conditions. The traditional classifications of bariatric surgeries labeled them as “restrictive,” “malabsorptive,” or “mixed” types of procedures depending on the anatomical rearrangement of each one of them. This conventional categorization of bariatric surgeries assumed that the “restrictive” procedures induce their weight loss and metabolic effects by reducing gastric content and therefore having a smaller reservoir. Similarly, the “malabsorptive” procedures were thought to induce their main energy homeostatic effects from fecal calorie loss due to intestinal malabsorption. Observational data from human subjects and several studies from rodent models of bariatric surgery showed that neither of those concepts is completely true, at least in explaining the multiple metabolic changes and the alteration in energy balance that those two surgeries induce. Rather, neuro-hormonal mechanisms have been postulated to underly the physiologic effects of those two most performed bariatric procedures. In this review, we go over the role the autonomic nervous system plays- through its parasympathetic and sympathetic branches- in regulating weight balance and glucose homeostasis after SG and RYGB.

Correlation Between Preoperative Gastric Volume and Weight Loss After Laparoscopic Sleeve Gastrectomy

Purpose

Long-term studies reported inadequate weight loss or weight regain after laparoscopic sleeve gastrectomy (LSG). This study investigated a possible relationship between preoperative gastric volume (GV) measured by CT volumetry and weight loss one year after LSG.

Methods

This prospective study included 120 patients scheduled for LSG. 3D CT gastric volumetry was done before surgery. The weight loss in the first year was serially recorded. The primary outcome measure was the correlation between preoperative GV and postoperative weight loss after one year. The secondary outcomes were the correlation between preoperative GV and other patients’ characteristics as age and body mass index (BMI).

Results

Weight and BMI decreased significantly up to 12 months. The percentage of excess weight loss (%EWL) at 6 and 12 months was significantly higher than at three months. Preoperative GV was 1021 ± 253, ranging from 397 to 1543 mL. GV was not related to sex, age, weight, height, postoperative weight, and BMI.

Conclusion

Preoperative gastric volume cannot predict weight loss one year after LSG. It is not correlated with age, sex, or preoperative weight, and BMI.

Micronutrients deficiences in patients after bariatric surgery

Bariatric surgery is an effective option for managing obesity and has gained general acceptance among patients in recent years. Generally, despite the high caloric intake, a bad nutritional habit of obese people results in the deficiency of several vitamins, minerals, and trace elements essential for body metabolism and normal physiological processes. Additionally, the current bariatric surgical approaches such as sleeve gastrectomy (SG), Roux-en-Y-gastric bypass (RYGB), laparoscopic adjustable gastric banding (LAGB), and jejunoileal bypass (JIB) can cause or exacerbate these deficiencies. Based on several reports, it appears that the various bariatric surgical procedures affect nutrient absorption differently. Being purely restrictive, LAGB and SG affect the absorption of iron, selenium, and vitamin B₁₂, while RYGB, JIB, and biliopancreatic diversion have a more profound impact on the absorption of essential vitamins, minerals, and trace elements. Nutritional deficiencies in vitamins, minerals, and trace elements may follow bariatric surgery and are associated with clinical manifestations and diseases, including anemia, ataxia, hair loss, and Wernicke encephalopathy. The present review summarizes some of the major vitamin and micronutrient deficiencies associated with bariatric surgery, particularly those presented post-surgically. To avoid any adverse consequences of vitamin and trace element deficiency, proper monitoring and tests are recommended at any stage, from pre- to post-surgery (periodical check-up), followed by specific and individual nutritional supplementation treatments and a proper healthy diet.

Measurement of Stomach Wall Thickness to Guide Staple Selection during Sleeve Gastrectomy

BACKGROUND

Sleeve gastrectomy has been considered a primary bariatric surgery; however, surgeons concerned with staple line leakage often query whether staples selected during stomach resection are of an appropriate size. This study aimed to measure gastric wall thickness using pathology laboratory measurements and to identify variables correlated with stomach wall thickness in patients who had undergone laparoscopic sleeve gastrectomy.

METHODS

We obtained fresh resected stomach wall specimens from 30 patients. Stomach wall thickness was immediately measured postoperatively, comprising the muscle layer of the antrum, body, and fundus. Results were correlated with body mass index (BMI), age, and sex and with diagnoses of presurgical diabetes, hypertension, hyperlipidemia, and fatty liver.

RESULTS

Stomach wall thickness ranged from 3.4 ± 4.3 mm to 1.0 ± 9.6 mm at the antrum. Except for the whole layer at the body wall, there was no significant correlation between wall thickness and other factors. At the body wall, whole layer wall thickness was found to positively correlate with age, sex, diabetes, and smoking (r = 0.469, - 0.391, 0.396, and 0.349, respectively; p < 0.05 in all patients).

CONCLUSION

Stomach wall thickness varied among patients who had undergone laparoscopic sleeve gastrectomy according to samples taken at three stomach wall sites. The range in wall thickness was normal, and thus, surgeons need not hesitate in selecting the staple height. Also, our study may be helpful to guide surgeon choice concerning the third or fourth staple around the body area when considering a patient's independent factors.

Impact of Resected Gastric Volume on Postoperative Weight Loss after Laparoscopic Sleeve Gastrectomy

Among the bariatric surgery community, it has recently emerged the idea of a possible association between resected gastric volume (RGV) and weight loss after laparoscopic sleeve gastrectomy (LSG). If the size of the sleeve depends on the bougie caliber, the resected volume of the stomach remains something which is not possible to standardize. The aim of the study was to investigate a possible relationship between RGV and weight loss after LSG. We developed a mathematical method to calculate the RGV, based on the specimen size removed during LSG. Ninety-one patients (63 females and 28 males) affected by morbid obesity were included in the study. They underwent LSG between 2014 and 2016. Mean preoperative BMI was 45 ± 6.4. At 1 year after LSG, the mean BMI was 30 ± 5.3 and the EWL% was 65 ± 20.2. The statistical analysis of RGV, BMI, and EWL% at 1-year follow-up did not find any correlation between the volume of stomach removed and the weight loss after LSG. Further studies in the future should clarify the potential role of RGV during LSG. This trial is registered with ClinicalTrials.gov NCT03938025.