Perioperative and Postoperative Effects of Preoperative Low-Calorie Restrictive Diets on Patients Undergoing Laparoscopic Sleeve Gastrectomy

Low-calorie diets are effective for weight loss in patients undergoing benign upper gastrointestinal surgery: a systematic review and meta-analysis

BACKGROUND

Obesity may increase surgical complexity in patients undergoing abdominal surgery by limiting visualization and increasing the risk of peri-operative complications. A preoperative reduction in weight and liver volume may improve surgical outcomes. The aim of our study was to evaluate the efficacy of a low-calorie diet (LCD) versus a very low-calorie diet (VLCD) in reducing weight and liver volume prior to laparoscopic surgery.

METHODS

A systematic search was conducted using the following inclusion criteria: obese patients undergoing preoperative weight loss using a VLCD or LCD, evaluation of liver volume reduction, and the use of an imaging modality before and after the diet.

RESULTS

A total of 814 patients from 21 different studies were included in this systematic review and meta-analysis, with 544 female patients (66.8%) and a mean age range between 24 and 54 years old. There was a total mean weight loss of 6.42% and mean liver volume reduction of 16.7%. Meta-analysis demonstrated that a preoperative diet (LCD or VLCD) significantly reduced weight [SMD = - 0.68; 95% CI (- 0.93, - 0.42), I2 = 82%, p ≤ 0.01] and liver volume [SMD = - 2.03; 95% CI (- 4.00, - 0.06), I2 = 94%, p ≤ 0.01]. When assessed individually, a VLCD led to significant weight reduction [SMD = - 0.79; CI (- 1.24; - 0.34), p ≤ 0.01, I2 = 90%], as did an LCD [SMD = - 0.60; CI (- 0.90; - 0.29), p ≤ 0.01, I2 = 68%). Similarly, there was a significant reduction in liver volume following a VLCD [SMD = - 1.40; CI (- 2.77, - 0.03), p ≤ 0.01, I2 = 96%], and an LCD [SMD = - 2.66; CI (- 6.13, 0.81), p ≤ 0.01, I2 = 93%]. However, there was no significant difference between the two regimens.

CONCLUSIONS

Preoperative restrictive calorie diets are effective in reducing weight and liver volume prior to laparoscopic surgery. Whilst a VLCD was better than an LCD at reducing both weight and liver volume, the difference was not significant.

Multimodal approach utilising a weight management programme prior to bariatric surgery in patients with BMI ≥50 kg/m2: A propensity score matching retrospective cohort study

We evaluated preoperative weight loss and days from initial consult to surgery in patients with BMI ≥50 kg/m2 who were and were not enrolled in medical weight management (MWM) prior to laparoscopic sleeve gastrectomy. We retrospectively identified patients with BMI ≥50 kg/m2 who had primary sleeve gastrectomy between 2014 and 2019 at two bariatric surgery centres in our healthcare system. Patients presenting after 2017 that received preoperative MWM (n = 28) were compared to a historical cohort of non-MWM patients (n = 118) presenting prior to programme initiation in 2017 on preoperative percent total body weight loss (%TBWL) and days from initial consult to surgery. A total of 151 patients (MWM, 33; non-MWM, 118) met inclusion criteria. BMI was significantly greater in MWM versus non-MWM (p = .018). After propensity score matching, median BMI at initial consult in non-MWM versus MWM no longer differed (p = .922) neither were differences observed on the basis of weight, age, sex, race or ethnicity. After PSM, MWM had significantly lower BMI at surgery (p = .018), lost significantly more weight from consult to surgery (p < .001) and achieved significantly greater median %TBWL from consult to surgery (p < .001). We noted no difference between groups on 6-month weight loss (p = .533). Days from initial consult to surgery did not differ between groups (p < .863). A preoperative MWM programme integrated into multimodal treatment for obesity in patients with a BMI ≥50 kg/m2 resulted in clinically significant weight loss without prolonging time to surgery.

Evaluate the Effects of Different Types of Preoperative Restricted Calorie Diets on Weight, Body Mass Index, Operation Time and Hospital Stay in Patients Undergoing Bariatric Surgery: a Systematic Review and Meta Analysis Study

Previous studies investigated low-calorie diets (LCD), very-low-calorie diets (VLCD), and very-low-calorie ketogenic diets (VLCKD) in relation to weight loss and outcomes for bariatric surgery patients. However, the overall effects of these diets on various outcomes remain unclear. This study aimed to assess the impact of preoperative restricted calorie diets on weight, body mass index (BMI), operation time (OT), and hospital stay (HS) in bariatric surgery patients. Seventeen articles were analyzed, revealing the highest weight loss (-8.62) and BMI reduction (-5.75) with VLCKD. Due to insufficient data, the impact of these diets on OT and HS could not be determined. Further interventional studies are required to determine the ideal preoperative diet that achieves optimal weight loss, patient compliance, tolerance, acceptance, and surgical outcomes.

[Indications and preoperative planning for bariatric surgery]

These clinical practice guidelines represent the consensus opinion of a group of Austrian specialist physicians associated with the treatment of obesity. The recommendations incorporate the current literature and guidelines and aim to balance both procedural feasibility and patient acceptance and adherence. Special emphasis was placed on simplification of the preoperative clarification and maximum patient safety. Therefore, this article makes no claim to be complete in all fields.

Is It Possible to Estimate the Liver Left Lobe Volume Using Preoperative Data Before Bariatric Surgery?

PURPOSE

Retraction of the left lobe of the liver (LLL) is an important step in bariatric surgical procedures. A good liver retraction will both facilitate the operation and reduce complications. The aim of the study is to identify patients with large LLL with preoperative anthropometric and laboratory data, and to reveal complications due to large LLL.

MATERIALS AND METHODS

The data of 245 patients who underwent bariatric surgery in our department between April 2019 and March 2021 were retrospectively analyzed. The patients were divided into two groups according to the visibility of the caudate lobe of the liver, the left diaphragmatic artery-vein, and the fat pad on the esophagus after liver retraction.

RESULTS

Univariate analyses revealed significant differences in BMI, waist and hip circumferences, TG, DM, and HbA1c values, but only BMI (p = 0.001) and the presence of DM (p = 0.017) were found to be independent predictors of LLL size. BMI ≥ 42.1 kg/m² indicates the size of LLL with 83% sensitivity and 49% specificity. Retractor-related complications were significantly higher in the large LLL group (p = 0.036). There was no difference between the two groups in terms of complications related to trocar insertion (p = 0.014) and postoperative liver enzyme levels (p = 0.714). The operation time (laparoscopic sleeve gastrectomy [LSG]; p = 0.021) (laparoscopic Roux-N-Y gastric bypass [LRYGB]; p = 0.020) and the amount of bleeding (LSG; p < 0.001) (LRYGB; p = 0.011) are higher in patients with large LLL.

CONCLUSION

Large LLL can be predicted and complications may be reduced with the help of preoperative data.

Preoperative weight loss in women with obesity in gynaecologic oncology: A retrospective study

To retrospectively review the efficacy of short term supervised medical weight loss for women with obesity, body mass index (BMI ≥40 kg/m² ) in gynaecologic oncology, and the associated perioperative and pathologic outcomes. A retrospective study of a dedicated preoperative weight loss clinic for gynaecologic oncology patients from March to December 2019. Statistical analysis was performed with McNemar's test for correlated proportions, Pearson's correlation tests for continuous variables, and paired t-tests to compare means. Generalized estimating equations (GEE) were used to determine the factors associated with weight loss over time. A P-value of <.05 was used for statistical significance. Review of cases up-graded after surgery was performed by a gynaecologic pathologist. There were a total of 49 women included in the study. The most common referral reason was endometrioid carcinoma or hyperplasia of the endometrium (77.6%). Mean initial weight was 130.2 kg, and corresponding mean BMI 48.1 kg/m² . Patients attended on average nine preoperative weight loss visits. A significant difference between initial weight and weight at surgery was demonstrated, from 129.6 to 118.0 kg (8.4% weight loss) (P < .0001). This difference persisted to their post-surgical visit, with an additional mean loss of 1.89 kg (9.4% weight loss) (P = .044). The majority (92.1%) of patients with endometrial pathology had surgical management, and of these 85.7% were minimally invasive. Preoperative weight loss is a feasible option in gynaecologic oncology patients. Greater understanding of clinical significance, follow-up, and ideal target population for this intervention is needed.

Pediatric Metabolic and Bariatric Surgery

Childhood obesity can lead to comorbidities that cause significant decrease in health-related quality of life and early mortality. Recognition of obesity as a disease of polygenic etiology can help deter implicit bias. Current guidelines for treating severe obesity in children recommend referral to a multidisciplinary treatment center that offers metabolic and bariatric surgery at any age when a child develops a body mass index that is greater than 120% of the 95th percentile. Obesity medications and lifestyle counseling about diet and exercise are not adequate treatment for severe childhood obesity. Early referral can significantly improve quality and quantity of life.

Validity and efficacy of diets used for preoperative weight reduction among patients qualified for bariatric surgery

INTRODUCTION

Bariatric surgery is the most effective method of weight reduction among patients suffering from morbid obesity. Reduction of body weight before surgery is an important element. The aim of the study was to present the current knowledge on preoperative weight reduction and diet for this purpose.

MATERIAL AND METHODS

To achieve the aims of the paper, articles available in the PubMed / MEDLINE database published in 2005-2020 were used, as well as the guidelines of societies such as Metabolic and Bariatric Surgery Chapter of the Association of Polish Surgeons, American Association of Clinical Endocrinologists, The Obesity Society and American Society for Metabolic &amp; Bariatric Surgery, International Federation for Surgery of Obesity and Metabolic Disorders-European Chapter and European Association for the Study of Obesity.

RESULTS

Studies show that even a modest reduction in weight in the early preoperative period facilitates surgery and reduces the number of complications. The available data do not support the effect of preoperative weight loss on increased postoperative weight loss. The use of balanced, energy-restricted diet in the preoperative period prepares the patient for changes in the way of nutrition, which improves the nutritional status of patient. Low calorie (LCD) or very low calorie (VLCD) diet can be an effective method of weight loss before surgery, however, this approach does not allow to modify eating habits. The use of a very low calorie ketogenic diet (VLCKD) remains under discussion.

CONCLUSIONS

There is a need for large randomized trials to assess short and long term benefits of preoperative weight loss and methods of weight loss among patients qualified for bariatric surgery, also the standardization of nutritional management in the preoperative period.

Effectiveness of a Low-Calorie Diet for Liver Volume Reduction Prior to Bariatric Surgery: a Systematic Review

An energy-restricted diet is often prescribed before bariatric surgery to reduce weight and liver volume. While very-low-calorie diets (VLCDs, 450–800 kcal per day) have shown to be effective, the effectiveness of low-calorie diets (LCDs, 800–1500 kcal per day) is less obvious. The objective of this systematic review was to elucidate the effectiveness of LCD on liver volume reduction in patients awaiting bariatric surgery. Eight studies (n = 251) were included describing nine different diets (800–1200 kcal, 2–8 weeks). An LCD was effective in liver volume reduction (12–27%) and weight loss (4–17%), particularly during the first weeks. The LCD showed an acceptable patients’ compliance. Based on these findings, an LCD (800–1200 kcal), instead of a VLCD, for 2 to 4 weeks should be preferred.

Impact of a preoperative low-calorie diet on liver histology in patients with fatty liver disease undergoing bariatric surgery

BACKGROUND

A low-calorie diet (LCD) before bariatric surgery has been shown to reduce liver volume and facilitate ease of operation. It is estimated that 75%-100% of individuals undergoing bariatric surgery have nonalcoholic fatty liver disease (NAFLD).

OBJECTIVES

We aimed to investigate how an LCD affects liver histology in the setting of NAFLD.

SETTING

University Hospital, United States.

METHODS

Forty intraoperative liver specimens were analyzed histologically as follows: 20 with and 20 without a preoperative 2-week, 1200 kcal/d LCD. Weight was measured prediet, at surgery, and 6 months after surgery. NAFLD activity score was used to grade liver histology at surgery. The NAFLD activity score scores steatosis, lobular inflammation, hepatocellular ballooning, and fibrosis.

RESULTS

The non-LCD group (n = 20) had mean weight at surgery of 136.1 ± 24.1 kg. The LCD group (n = 20) had initial mean weight of 128.6 ± 25.4 kg, with presurgical weight loss of 3.43 kg (range, 0-9.3 kg), mean change in body mass index 1.24 kg/m² (2.66% total weight loss) on an LCD. The LCD group had significantly less steatosis (P = .02), fewer foci of lobular inflammation (P = .01), and less hepatocellular ballooning (P = .04) compared with the non-LCD group; with no difference in degree of fibrosis. Fewer patients in the LCD group had nonalcoholic steatohepatitis with ballooning (P = .04). Weight loss on an LCD before bariatric surgery was predictive of weight loss 6 months after surgery (P = .026).

CONCLUSIONS

A 2-week LCD before bariatric surgery is associated with significant improvement in steatosis, inflammation, and hepatocellular ballooning in NAFLD. Among LCD patients, preoperative weight loss was associated with improved 6-month weight loss and liver function.