Perioperative management - Sleeve Gastrectomy / Laparoscopic Gastric Sleeve

As with all other approaches in the treatment of obesity, surgical measures do not address the root cause, as the actual cause of obesity is complex and still largely unknown. Based on the guidelines in developed countries, surgery is indicated in the following patients:

BMI ≥ 40 kg/m², where nonsurgical treatment (diet, exercise, behavioural and drug-based therapies, alone or in combination) has been shown to be unsuccessful.

BMI ≥ 35 kg/m² with one or more obesity-associated comorbidities such as type 2 diabetes mellitus, coronary artery disease, heart failure, hyperlipidaemia, arterial hypertension, nephropathy, obstructive sleep apnoea syndrome, obesity hypoventilation syndrome, Pickwickian syndrome, non-alcoholic fatty liver or non-alcoholic steatohepatitis, gastro-oesophageal reflux disease, asthma, chronic venous insufficiency, urinary incontinence, immobilising joint disease, impaired fertility, or polycystic ovary syndrome.

Primary indication without a previous attempt at nonsurgical treatment:

• BMI ≥ 50 kg/m²
• A nonsurgical treatment attempt is deemed unpromising or futile by the multidisciplinary team.
• In patients with severe comorbidities and associated complications that do not allow postponement of surgical intervention.

A primary indication in the sense of metabolic surgery can be established in patients with a BMI ≥ 40 kg/m² and coexisting type 2 diabetes mellitus if the treatment goal is improvement of the glycaemic metabolic state rather than weight reduction. To establish the indication for surgery, evidence of exhausted conservative therapy in the sense of bariatric surgery is not required in these patients [American Diabetes Association 2017].

The following parameters must be considered when choosing the procedure:

• the patient's baseline weight (BMI)
• the expected weight loss (EWL)
• compliance
• age
• a possible wish to have children in women
• comorbidities (particularly diabetes mellitus)
• the surgical risk

Other factors to consider include:

• gender
• profession
• eating habits

There is no surgical procedure that can be recommended across the board for all patients; rather, the choice of procedure should be individually oriented to the patient's medical, psychosocial, and general life circumstances.

In patients with extreme forms of obesity (BMI > 50 kg/m²) and/or considerable comorbidity, staged concepts may be considered, e.g. sleeve gastrectomy first, then gastric bypass, in order to reduce the perioperative risk. Ideally, all procedures should be performed laparoscopically.

Sleeve gastrectomy (SG):

SG was initially established in biliopancreatic diversion with duodenal switch (BPD-DS) for additional food restriction and ulcer prophylaxis. It has since become established as a surgical procedure in its own right. The gastric sleeve can readily be converted to a gastric bypass if necessary.

Excess weight loss 2 years after SG does not differ significantly from weight loss after pRYGB (proximal gastric bypass). However, in long-term comparison it is inferior to RYGB with respect to weight control, reflux control, and diabetes remission. Perioperative complications, on the other hand, occur significantly less frequently after SG.

Because of its low morbidity compared to the other methods, SG is recommended in the following cases:

• old age
• very young age because of the lower risk of malabsorption
• very high BMI range because of the many options should conversion surgery become necessary
• procedure of choice in disorders requiring endoscopic access: type A gastritis, access to the papilla, e.g. in bile duct stenosis.
• Crohn disease
• need to take medication requiring level monitoring

• In type 2 diabetes, a bypass should rather be considered, as better results can be expected.
• Sleeve gastrectomy is not suitable for obese patients with severe heartburn/reflux.
• Wasting diseases such as malignant neoplasms, untreated endocrine causes, and chronic diseases that are exacerbated by a postoperative catabolic metabolism.
• pregnancy
• lack of compliance
• unstable psychopathological conditions, untreated bulimia nervosa, active substance dependence
• Disorders of the stomach and duodenum
• Since bleeding in the gastric remnant cannot be treated endoscopically, the procedure is contraindicated in patients on
  • lifelong anticoagulant medication (phenprocoumon or ASA)
  • chronic need for analgesics (ulcerogenic)

The following are not contraindications:

• Advanced age (≥ 65 years) [18]
• Chronic inflammatory bowel disease such as Crohn's disease and ulcerative colitis [19]
• Desire for future fertility
• Type 1 diabetes mellitus (T1DM)

Preoperative gastroscopy should be performed before all bariatric procedures to rule out relevant diseases of the oesophagus or stomach, whose incidence is increased in obesity.

The following diseases should be noted and investigated and treated before surgery:

• Reflux
• Erosive gastritis
• Helicobacter pylori infections
• Barrett's oesophagus
• Oesophageal carcinoma
• Gastric tumours
• Ulcera ventriculi et duodeni.

Risk evaluation has a high priority in obesity surgery. In addition to the standard diagnostics (ECG, chest X-ray, laboratory), it always includes a pulmonary function test and an assessment of the nutritional status.

Routine polysomnography is standard in US clinics, as between 77 and 88% of patients there have sleep apnoea.

Preoperative preparation is carried out in accordance with the recommendations of the current S3 guideline "Surgery for Obesity and Metabolic Disorders" as well as the standards of certified obesity centres. The aim is to optimise the perioperative risk profile and to ensure long-term treatment success.

Interdisciplinary indication

Before performing a bariatric operation, the indication should be reviewed and documented on an interdisciplinary basis in accordance with the requirements of the current S3 guideline. The preoperative evaluation particularly includes assessment by internal medicine, nutritional medicine, psychology/psychosomatics and surgery.

Preoperative weight reduction and liver conditioning

Preoperative weight reduction is recommended. Particularly in patients with pronounced visceral obesity or fatty liver, a calorie-reduced or formula diet (low-calorie diet, LCD, or very-low-calorie diet, VLCD) for 1–2 weeks preoperatively can lead to a reduction in liver volume and visceral adipose tissue, thereby improving operating conditions.

Nicotine abstinence

Patients should be urged to abstain consistently from nicotine. Smoking increases the risk of pulmonary complications, wound healing disorders and postoperative leaks and should be stopped, if possible, several weeks before the procedure.

Optimisation of comorbidities

Obesity-associated comorbidities should be optimally managed preoperatively. These include in particular:

Diabetes mellitus

Arterial hypertension

Obstructive sleep apnoea syndrome

Coronary heart disease

Heart failure

Chronic lung diseases

In patients with sleep apnoea syndrome, the perioperative availability of an existing CPAP therapy should be ensured.

Medication management

The adjustment of antidiabetic, anticoagulant and other risk-relevant medications is carried out in accordance with the current recommendations on perioperative medication management. Particular attention is paid to anticoagulants, platelet aggregation inhibitors and modern antidiabetic agents including GLP-1 receptor agonists.

Skin and infection status

Preoperatively, skin infections, intertrigo, chronic wounds as well as diabetes-related skin and soft tissue changes should be identified and treated. These can increase the risk of postoperative wound complications.

Thromboembolism prophylaxis

Patients with morbid obesity have an increased risk of venous thromboembolism. Perioperative prophylaxis comprises:

Early mobilisation

Physical measures (e.g. medical thromboprophylaxis stockings or intermittent pneumatic compression)

Weight-adapted medicinal thromboprophylaxis with low-molecular-weight heparin in accordance with the current guidelines

Due to the elective nature of the procedure, comprehensive informed consent must be obtained well in advance. In addition to the general risks of a laparoscopic operation, particular attention must be paid to explaining the procedure-specific risks, the long-term consequences of the intervention, and the importance of lifelong follow-up care.

General surgical risks

• The general risks include, in particular:
• Bleeding and secondary haemorrhage with possible need for transfusion
• Infections and wound healing disorders
• Thromboembolic complications
• Injury to adjacent organs, vessels or nerves
• Positioning injuries
• Complications of the laparoscopic technique, including pneumothorax or trocar injuries
• Need for conversion to laparotomy

Specific risks of the sleeve gastrectomy

• Sleeve gastrectomy is an irreversible procedure in which a large part of the stomach is permanently removed.
• The specific risks include, in particular:
• Staple line insufficiency (leakage) with the risk of peritonitis, sepsis and reoperation
• Secondary haemorrhage in the area of the resection line
• Stenoses or functional emptying disorders of the sleeve stomach
• Injury to adjacent organs, particularly the oesophagus, spleen and pancreas
• New-onset or increasing gastro-oesophageal reflux symptoms
• Insufficient weight loss or weight gain over the long term
• Need for later revisional or conversion surgery

Long-term outcomes and follow-up

• The patient must be informed that long-term treatment success depends substantially on their own cooperation. This includes in particular:
• Permanent dietary change
• Regular physical activity
• Attendance at the recommended follow-up examinations
• Long-term monitoring of possible vitamin, trace element and protein deficiency states
• The need for lifelong medical follow-up care should be explicitly addressed and documented.