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. 

Since sleeve gastrectomy can only be performed by laparoscopy or laparotomy, this requires either general anesthesia or general anesthesia in pneumoperitoneum.
Generally, fiberoptic intubation must be possible in obese patients. Video laryngoscopy markedly facilitates intubation.

Ileus positioning
Maximum relaxation is required throughout the entire operation to assure maximum range of motion in the surgical field already constricted by the abdominal and visceral fat. In addition, the anesthesiologist should be aware that anti-Trendelenburg positioning may increase ventilation pressure, thus necessitating PEEP ventilation.

Central venous catheter
In high-volume centers it is generally possible to forgo a central venous catheter (CVC) since in extremely obese patients this is associated with its own morbidity. However, in lower-volume centers and for longer operating times a CVC is recommended. Furthermore, a CVC provides good venous access during the critical first 24-28 hours post surgery when the peripheral venous situation is generally precarious.
This central venous line may also be placed “peripherally” in the brachial or radial vein to avoid the risk of pneumothorax.

Nasogastric tube:
A nasogastric tube (calibration bougie) must be placed during the operation and moved as directed by the surgeon when fashioning the gastric sleeve. Following gastric resection, the sleeve is filled with methylene blue to check for any leakage. This also requires close cooperation with the surgeon. Usually, the nasogastric tube can be carefully removed following successful leakage testing. 

Place the patient in anti-Trendelenburg position on the bariatric operating table rated for the patient weight. These tables should also be equipped with side extensions to accommodate very wide patients. Position the video monitors above the patient’s left and right shoulders. Both arms abducted. Spread both legs.

The surgeon stands between the patient’s spread legs. The assistant operating the camera stands to the left of the patient. A pneumatic liver retractor on the patient‘s right side retracts the left hepatic lobe. The scrub nurse stands to the left of the patient.

• • Basic laparoscopy set
  • Optical trocar (in the video Xcel trocar)
  • One 5 mm trocar
  • Three 12 mm trocars 
  • Ultrasonic or bipolar electrocautery sealing hemostatic systems for dissection and division
  • One RF device
  • Laparoscopic staplers/ Echelon 60 mm (green to blue cartridges)
  • Atraumatic intestinal graspers 
  • Laparoscopic needle holders
  • Calibration bougie 32 Fr
  • 30° laparoscope recommended
  • High-volume insufflator
  • Pneumatic holder for liver retractor

Postoperative analgesia: 

Intravenous, non-ulcerogenic standard medication will generally suffice.
Follow this link to Prospect (Procedures Specific Postoperative Pain Management)
Follow this link to the current German guideline Behandlung akuter perioperativer und posttraumatischer Schmerzen [Treatment of acute perioperative and posttraumatic pain].

Postoperative medical management:

• • Remove the nasogastric tube at the end of the operation. Routine radiography is not required. 
  • Vitamin supplementation: Since the normal digestive pathway is maintained during this procedure, vitamin and mineral deficiencies are quite rare. However, because the gastric sleeve usually results in rapid massive weight loss, vitamin and mineral supplementation is still recommended in consultation with a physician. Should “intrinsic factor” no longer be produced in sufficient quantity, vitamin B12 may have to be administered as short-term i.v. infusion or by intramuscular injection.
  • Weight reduction is not possible if high-calorie foods and liquids are ingested. Therefore, strict compliance with the recommended diet is mandatory for adequate weight loss. Good nutritional counseling, also as part of postoperative management, is strongly recommended for the patient.
  • Proton pump inhibitors (PPI) for two weeks; special attention should be paid to reflux disorder during SG follow-up since there is the potential risk of developing Barrett epithelium.
  • Sport: Motivation for sustained exercise optimizes weight loss and stabilizes it in the long term. The patient should run, cycle or do aerobics for at least 30 minutes five times a week. In primary wound healing, a muscle building weight-training program for the upper body may also be recommended after postoperative week 6. 
  • Follow-up: During the first year all patients are seen for follow-up visits every three months to monitor their appropriate dietary and exercise habits. Thereafter, at least once a year indefinitely in order to diagnose malnutrition and malnourishment at an early stage and be able to address this. Long-term monitoring by a nutritionist is advisable to prevent vitamin, mineral and protein or even fluid deficiencies.
  • Cosmetic plastic surgery  

Deep venous thrombosis prophylaxis: 

Venous thromboembolism with secondary pulmonary embolism is a serious perioperative risk, especially for the combination of obesity and major abdominal surgery.

While the current guidelines classify the risk of thrombosis as moderate, most centers consider this to be a high risk.

The 2010 NICE guidelines issued the following recommendations:

• • Every bariatric patient without an increased risk of bleeding should receive deep venous thrombosis prophylaxis with low-molecular-weight heparin in a weight-adjusted dosage. The reported higher risk of bleeding while receiving DVT prophylaxis is 1.8%.
  • Mechanical thrombosis prophylaxis using anti-embolism stockings should be started on hospital admission. Intraoperative intermittent pneumatic compression is recommended.
  • DVT prophylaxis should be continued until the patient is fully ambulant, usually until postoperative day 5 to 7.

Note: Renal function, HIT II (history, platelet check)
Follow this link to the current German guideline Guideline on prophylaxis in venous thromboembolism.

Ambulation: 

Start already in the evening of the day of surgery; increasing ambulation is desirable but lifting anything heavier than around 3 kg should be avoided until postoperative week 6.

Physical therapy: 

Possibly prophylactic respiratory therapy for pneumonia

Diet: 

In the first two weeks after surgery, the patient may only ingest liquid food. This is followed by a gradual change to a pulpy and then light diet, ideally under the supervision of a dietitian. In the long term, patients will have to divide their food intake into about five to seven smaller meals per day.

Bowel movement: 

Since the normal digestive tract is preserved, other than a mild laxative from postoperative day 3 no further measures are needed.

Work disability: Patients are normally discharged on postoperative day 3 to 5 provided that their fluid intake is adequate.