Perioperative management - Laparoscopic sleeve gastrectomy

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, nonsurgical treatment (diet, exercise, behavioral and drug-based therapies, alone or in combination) was found to have been unsuccessful.

BMI ≥ 35 kg/m² with one or more obesity-associated comorbidities such as T2DM; coronary artery disease; heart failure; hyperlipidemia; arterial hypertension; nephropathy; obstructive sleep apnea syndrome; obesity hypoventilation syndrome; Pickwick syndrome; nonalcoholic fatty liver or nonalcoholic fatty liver hepatitis; gastroesophageal reflux disease; asthma; chronic venous insufficiency; urinary incontinence; immobilizing joint disease; fertility limitations; or polycystic ovary syndrome.

Primary indication without previous attempt at nonsurgical treatment:

• • BMI ≥ 50 kg/m²
  • A nonsurgical treatment attempt is deemed unpromising or futile by the multispecialty team.
  • In patients with particularly severe concomitant and secondary diseases that do not allow postponement of surgery.

Primary indication for metabolic surgery is possible in the presence of BMI ≥ 40 kg/m² and coexisting T2DM, if the treatment goal is more to improve the glycemic metabolic state rather than to achieve weight loss. These patients do not require evidence of exhaustive nonsurgical treatment to establish the indication for bariatric surgery [American Diabetes Association 2017].

 The following parameters must be considered when choosing the procedure:

• • Patient baseline weight (BMI)
  • Expected weight loss (EWL)
  • Compliance
  • Age
  • Family planning not yet completed in women
  • Comorbidities (particularly diabetes)
  • Surgical risk

Other factors to consider include:

• • Gender
  • Profession
  • Eating habits

There is no single surgical procedure that can be recommended for all patients in general; rather, the choice of procedure should be tailored to the patient's personal medical, psychosocial, and general circumstances.

In patients with extreme obesity (BMI > 50 kg/m²) and/or significant comorbidity, a staged approach may be considered, e.g., sleeve gastrectomy first, followed by gastric bypass, to reduce the perioperative risk. Ideally, all procedures should be performed laparoscopically.

Sleeve gastrectomy (SG):

SG was initially introduced in biliopancreatic diversion with duodenal switch (BPD/DS) for additional transit restriction and ulcer prophylaxis. By now it has become established as a stand-alone surgical procedure. SG can easily be converted to gastric bypass if necessary. 

The excess weight loss two years after SG does not differ significantly from weight loss after pRYGB (proximal gastric bypass). However, in terms of long-term weight management, reflux management and diabetes remission it proved to be inferior to RYGB. But SG was associated with significantly fewer perioperative complications. 

Due to its low morbidity compared to the other procedures, SG is recommended in these cases:

• • Old age
  • Very young age because of the lower risk of malabsorption 
  • Very high BMI range due to the many options if conversion surgery becomes necessary
  • Procedure of choice in diseases requiring endoscopic access: Gastritis type A, access to the papilla, e.g., in bile duct stenosis.
  • Crohn disease 
  • Need to take medication with level monitoring

• • In T2DM, rather gastric bypass should be considered as better results can be expected
  • Sleeve gastrectomy is not appropriate for obese patients with severe heartburn/reflux.
  • Consuming diseases such as malignant neoplasms, untreated endocrine causes, chronic diseases exacerbated by postoperative catabolic metabolism.
  • Pregnancy
  • Poor compliance
  • Unstable mental conditions, untreated bulimia nervosa, active substance abuse
  • Gastric and duodenal disorders
  • Since bleeding in the gastric remnant cannot be treated endoscopically, sleeve gastrectomy is contraindicated in patients on
    • lifelong anticoagulants (phenprocoumon or ASA)
    • Chronic need for analgesics (ulcerogenic)

• • The following are not contraindications:
  • Advanced age (≥65 years) [18]
  • Chronic inflammatory bowel disease, e.g., Crohn disease and ulcerative colitis [19]
  • Family planning not yet completed 
  • Type 1 diabetes mellitus (T1DM) 

Preoperative gastroscopy should be performed before all bariatric procedures to rule out relevant diseases of the esophagus and stomach as their incidence is higher in obesity.

The following diseases should be noted and also assessed and treated before surgery:

• • Reflux
  • Erosive Gastritis
  • Helicobacter pylori infection 
  • Barrett esophagus 
  • Esophageal cancer 
  • Gastric tumors 
  • Gastric and duodenal ulcers

Risk assessment plays a key role in bariatric surgery. In addition to the standard diagnostic workup (ECG, chest x-ray, blood chemistry), this always includes pulmonary function testing and assessment of the nutritional status. 

Routine polysomnography is standard practice in US departments where between 77% and 88% of patients suffer from sleep apnea.

Preoperative measures with physical conditioning are initiated already prior to hospitalization:  No smoking, liquid diet at least two days before admission (ideally two weeks) and discontinuation of medication that could increase risk (metformin, oral anticoagulants, etc.).
General hygiene measures in preparation do not differ significantly from those in other procedures. Special attention should be paid to intertrigo in skin furrows and apposed skin surfaces, acute inflammatory leg ulcers, and diabetic changes in the lower extremities. Weight-adapted anticoagulants are started on the day of surgery.

The patients must be given comprehensive information as they will undergo an elective procedure. In addition to the general surgical risks associated with laparoscopy and the possible conversion to laparotomy, this must include the specific risks inherent in this procedure. The intraoperative risks, the short- and long-term sequelae including transfusion, and the mortality risk should be addressed. 

In general, sleeve gastrectomy involves major surgery with many potential complications even if it is a minimally invasive procedure.

General complications: 

• • Infection (including hepatitis), especially blood transfusion and transfusion of blood derivatives
  • Thrombosis and embolism 
  • Bleeding requiring blood transfusion
  • Secondary healing
  • Nerve damage
  • Skin and tissue damage caused by electric current, heat and/or disinfectants. This damage is rare and usually resolves spontaneously. 
  • Allergies and hypersensitivities (e.g., to medications, disinfectants, latex). 
  • Injury to the pharynx and esophagus when inserting the nasogastric tube. 
  • Injury to the urethra and bladder when inserting a urinary catheter 
  • Nerve and soft tissue damage during patient positioning with impaired sensation and very rarely paralysis of the arms and legs. The risk is considerably higher in extremely obese patients compared with those of normal weight. 
  • Gas insufflation during laparoscopic surgery may cause a feeling of pressure and shoulder pain. These quickly resolve, as does any crackling in the skin. If gas enters the pleural space (pneumothorax), this may require a chest tube.
  • There may be lingering numbness of the skin around the surgical scars
  • In some patients, the skin reacts with excessive scarring (keloid) because of impaired wound healing or patient predisposition; such scars can be painful and esthetically unappealing.

Special complications:

• • Sleeve gastrectomy is a surgical procedure irreversibly removing most of the stomach. The suture line on the gastric sleeve may result in complications such as leakage and fistula formation.
    • Conversion or redo surgery will become necessary in a percentage of cases that cannot yet be estimated ( treatment failure, refractory reflux)
    • Peritonitis necessitating reoperation may present secondary to suture line failure (leakage) 
    • Injury to the stomach, esophagus and other organs, such as the spleen and pancreas, is possible
    • In the event of splenic injury, splenectomy may be required resulting in increased susceptibility to infection 
    • The conversion from laparoscopic to open surgery may become necessary if complications arise or continuation of laparoscopic surgery is deemed to present an unacceptably high risk. This decision is taken by the surgeon.
    • Prior intra-abdominal operations, particularly in the left upper quadrant (stomach, diaphragmatic hernia, ...)  increase the surgical risk and degree of difficulty
    • Sometimes, surgery involving an abdominal incision can result in incisional hernia, which usually has to be repaired surgically. This may also occur at trocar sites in laparoscopic surgery. 
    • If the abdominal wall suture becomes dehiscent along its entire length after open surgery (burst abdomen), reoperation is unavoidable. 
    • Treatment success and avoidance of complications depend on patient cooperation. This requires the patient to be compliant with eating habits and adhere to follow-up visits. Failure to comply with the stated rules may lead to problems and reduce weight loss.