Perioperative complications of sleeve gastrectomy: Review of the literature.

Sleeve gastrectomy (SG) has known a spectacular rise worldwide during the last decade. The absence of digestive anastomosis simplifies the surgical technique, reducing anastomosis-related complications such as fistula, stricture and marginal ulcer. Furthermore, the respect for digestive continuity preserves the functions of pylorus, that regulates gastric emptying, and duodenum, where calcium, B vitamins and iron are absorbed. Despite the multiple advantages, SG also has specific complications such as bleeding, stenosis, portal thrombosis and leak. The staple line leak at the oesophagogastric junction is the most feared complication and its prevention remains difficult, as the involved mechanisms have been only partially elucidated. Its management is long and requires a multidisciplinary technical platform including Intensive Care Unit, digestive endoscopy and interventional radiology as well as a specialised surgeon. The aim of this review is to explain in detail the perioperative complications of SG, their prevention and treatment, referring to the most recent available literature.

INTRODUCTION

Sleeve gastrectomy (SG) has known a spectacular rise worldwide during the last decade.[1] The absence of digestive anastomosis simplifies the surgical technique, reducing anastomosis-related complications such as fistula, stricture and marginal ulcer. Furthermore, the respect for digestive continuity preserves the functions of pylorus, that regulates gastric emptying, and duodenum, where calcium, B vitamins and iron are absorbed. Nevertheless, SG also has specific complications that can be potentially life threatening and need a multidisciplinary and specialised management. The aim of this review is to explain in detail the perioperative complications specific to SG, their prevention and treatment.

METHODS

Review strategy

We conducted a systematic review on PubMed, Embase and Cochrane Library databases, adhering to PRISMA statement. The search was conducted in September 2017 and was not limited to any date range. We used as search terms: «sleeve gastrectomy», «complications», «post-operative morbidity», «postoperative mortality», «bleeding», «stenosis», «leak», «fistula», «portal thrombosis», «surgical treatment», «endoscopic treatment».

Data search was restricted to studies reporting on complications specific to SG. Experimental studies on animals were excluded from the study. Abstracts of the references retrieved were reviewed, and the full text of all potentially relevant studies was analysed for eligibility. Information from each study was extracted using a standardised data extraction form. Authors were not contacted.

We decided to divide the review in four paragraphs concerning intraoperative complications, post-operative mortality, post-operative morbidity and management of post-operative complications.

The following intraoperative complications specific to SG were retained: bleeding and splenic ischaemia.

The following post-operative complications specific to SG were retained: bleeding, stenosis, gastric leak and portal thrombosis.

Extraction of data and final synthesis was performed to provide an actualised picture of the above-mentioned topics. When the available data were not concordant, the authors selected those extracted from studies of superior methodological quality.

DISCUSSION

Intra-operative complications

Bleeding

Bleeding can occur during the division of the greater curvature vessels or during gastric stapling. The division of the short gastric vessels during the mobilisation of the gastric fundus in proximity to the splenic upper pole particularly exposes to the risk of haemorrhage. In case of bleeding, the injured vessel can retract, making any attempts to achieve haemostasis very difficult. If bleeding occurs, mechanical compression should be attempted first followed by the placement of haemostatic gauze. This technique results in the reduction of bleeding in most cases and helps to identify the vessel that may be coagulated or controlled with a metallic clip. The bleeding on the staple line can be controlled by stitches, metallic clips or bipolar coagulation. All these techniques are generally very effective and conversion to laparotomy for bleeding is unusual.

Splenic ischaemia

The division of the last fundus attachments can lead to the section of an artery vascularising the upper pole of the spleen, inducing a partial splenic ischaemia. The presence of adherences due to previous surgery (such as gastric banding) or anatomical variants such as a splenic artery to the upper pole of the spleen coming from the posterior gastric artery facilitates the occurrence of this complication. Change of colour of the splenic parenchyma is often immediate, giving a quick diagnosis. Clinical signs and biological repercussions depend on the extent of splenic ischaemia. Hyperthermia and biological signs of inflammation can often be mistaken for other complications such as a leak. Computed tomography (CT) confirms the diagnosis and helps to quantify the extent of splenic ischaemia. Antibiotics may be necessary according to importance of clinical signs, while in most cases, the evolution is spontaneously favourable.[2]

Post-operative mortality

The early post-operative mortality rate of bariatric surgery has been estimated between 0.12% and 2.8% according to national studies including a large population.[34567] A French study extracting data from a national prospective database reported a 0.13% mortality rate after SG between 2007 and 2012, based on a population of 47,092 patients.[8] The analysis of the mortality rate evolution over the study period showed a three-fold reduction, from 0.25% in 2007 to 0.08% in 2012. A similar decrease in mortality was also observed after gastric bypass (GB). On multivariate analysis, the following risk factors were associated with post-operative mortality: male gender, age >50 years, body mass index (BMI) >50 kg/m2, hypertension, type 2 diabetes, laparotomy versus laparoscopy and the hospital volume of bariatric procedures.[8]

Post-operative morbidity

The main studies in the literature show a post-operative morbidity more important after GB than after SG.[91011] Carlin et al., after matching 2949 patients operated on for SG with equal numbers of GB and band patients in the context of a state-wide registry, found that overall complication rate was lower after SG than after GB (6.3% vs. 10%, P < 0.0001).[12] Nevertheless, major complications’ rate was similar between SG (2.4%) and GB (2.5%, P = 0.736). The length of hospital stay, the rate of reoperation and readmission were also similar between SG and GB.[12]

Stroh et al. showed that hospitals with a volume of <100 procedures per year have a significantly higher complication rate compared to centres with a higher caseload (overall post-operative complication rate of 7.1% vs. 4.4% and post-operative surgical complication rate of 5.7% vs. 3.3%).[13]

Bleeding after SG is reported at an average rate of 2%.[14] Bleeding can be either intraperitoneal or endoluminal. Tachycardia and significant haemoglobin decrease on blood test guide the diagnosis. Pain is often absent or moderate. In case of endoluminal bleeding, melena is a typical but late sign, often preceded by general signs. CT scan eliminates other diagnoses and helps estimating the amount of an intraperitoneal bleeding for orientating management. Main risk factors for haemorrhage are related to the patient (hypertension, anticoagulant therapy and portal hypertension)[15] and to the surgical technique.[16] Hypertension must be controlled before surgery. Liver cirrhosis is no more considered as an absolute contraindication for bariatric surgery except in case of decompensation.[17] Nevertheless, portal hypertension enhances the risk of bleeding both at the level of the gastric staple line and at the level of the vessels of the greater curvature. In case of cirrhosis with portal hypertension, placement of a transjugular intrahepatic portosystemic shunt before bariatric surgery can reduce portal hypertension and consequently the risk for bleeding.

The choice of the cartridge height in relation to the thickness of the stomach and the respect of the length of tissue compression before stapling are two key elements to prevent bleeding.[16] Several technical options exist to reinforce the staple line: oversewing (by stitches or running sutures), metallic clips, biological sealants and buttress materials either absorbable or permanent. The meta-analysis by Wang et al. showed that staple line reinforcement through buttress material reduces the risk for bleeding (relative risk [RR] = 0.609, 95% confidence interval [CI] = 0.439–0.846, P = 0.003), while oversewing increases operative time without lowering complication rate.[18] Similarly, Gayrel et al. recently reported that the use of bioabsorbable staple line buttressing in patients at risk significantly reduces the postoperative bleeding rate (0 vs. 8.6%, P = 0.005).[15]

Stenosis

Stenosis is a rare complication after SG. Brethauer et al. found a rate of stenosis necessitating endoscopic or surgical treatment of about 0.6%.[19] Patients usually complain of vomiting with a feeling of fullness and regurgitation. Two kinds of stenosis have been described: anatomical and functional.[20]

Anatomical stenosis is usually situated at the level of the gastric angulus and is due to a wrong placement of the calibration tube. A running suture on the staple line can also lead to gastric stenosis, especially if it is performed without a calibration tube in place.

Two different types of functional stenosis after SG can be identified: type 1 is a localised twist of the gastric tube with the endoscopic appearance of an ‘antireflux valve’, while type 2 is owing to a spiral course of gastric stapling that winds around the stomach.[20]

Upper gastrointestinal (GI) endoscopy allows establishing diagnosis and dilating anatomical stenosis. Diagnosis of functional stenosis can be hard since the endoscope easily passes through and upper GI series is often noncontributory. CT scan with tridimensional reconstruction of the SG makes the diagnosis easy to establish.

The endoluminal bougie should be placed distally into the antrum to calibrate the SG along the entire length of the staple line. However, using an endoluminal bougie does not protect from creating a twisted SG. To avoid a twist, every successive staple firing must be performed along the same line. Excessive lateral traction by the surgeon on the posterior wall of the stomach is often involved in determining this complication. Finally, when the bougie is pushed too distally, it can bring to a longitudinal distension of the stomach. After withdrawal, stomach retracts, and the resultant SG will be shorter and larger than expected (‘accordion effect’).

Gastric leak

Gastric leak is the most feared complication of SG because of its complex management and its clinical evolution that may be particularly long. Up to 90% of SG leaks occur at the esophagogastric junction (EGJ) and rarely at the distal part of the staple line.[21] Leak rate is reported at 2.2%–2.4% according to two large systematic reviews of the literature.[2122] Noel et al., in a monocentric study of >2000 SG over 10 years, showed that leak rate decreased depending on the learning curve, with an average rate of 1% (0%–5.7%).[23] The same tendency was observed by Stroh et al., who analysed the German registry reporting 11,800 SG performed between 2007 and 2013.[13] More recently, Berger et al. reported a leak rate of <1% in 189,477 SG performed by 1634 surgeons at 720 American centres from 2012 to 2014 and included in the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP).[24] Several mechanisms are considered to be involved in the occurrence of leaks and include high pressure inside the gastric tube that is situated between two sphincters (pylorus and lower oesophageal sphincter), the presence of a functional or anatomical stenosis of the gastric tube beneath the leak, the precarious vascular supply to the EGJ which depends on left diaphragmatic artery and oesophageal descending arteries and the type of cartridge used for gastric stapling. A technical artifice, which is recommended, is avoiding to perform the last stapling too close to the oesophagus and/or to apply excessive lateral traction on the removed stomach. The stapler should, therefore, be applied about 1 cm lateral to the EGJ.

Multiple risk factors for a leak after SG have been identified. Stroh et al. demonstrated that intraoperative complications increased the risk of leak (RR: 2.27 and 95% CI: 2.12–7.44).[13] Male gender was found to be a risk factor in a multicentre study including 2834 patients,[25] but this result was not confirmed by Stroh et al. on multivariate analysis.[13] Age is not likely to increase the risk of surgical complications, particularly leaks, as shown by Stroh et al.[13] and by Sakran et al.[25] Nevertheless, a selection bias could explain this finding: it could be argued that older patients probably undergo a more thorough selection concerning severe comorbidities responsible for increasing the operative risk. Most studies reported no correlation between BMI and risk of fistula.[2225]

Several studies reported the conversion of band into SG to be associated with a higher risk of leak.[26] The evoked mechanisms are the presence of a fibrous capsule around the stomach that can interfere with healing and effectiveness of stapling as well as the technical difficulties.[26] Schneck et al. recently confirmed the superiority of the two-step conversion in terms of global complication rate (15.9% vs. 12.7%; P = 0.009) and shorter stay in Intensive Care Unit and lower re-hospitalisation rate.[27]

Concerning the surgical technique, the size of the calibration tube, the cartridge height and the use of staple line reinforcement materials have been analysed. Parikh et al. demonstrated that fistula rate is significantly lower when the size of the calibration bougie is >40 Fr.[22] The choice of the cartridge adapted to the thickness of the stomach is also important to minimise bleeding and leaks from the staple line. Nevertheless, no objective method exists allowing to correctly assess the thickness of the stomach before stapling. Several studies demonstrated that the thickness of the stomach changes significantly between the antrum and the fundus, which is the thinnest part of the stomach.[16] In addition, a recent study showed that the antrum was thicker in men, whereas the body and fundus were thicker in women. This study also demonstrated an important interindividual variability.[16] In case buttress materials are used, it must be considered that the thickness of the stomach to staple will be increased.[28]

Literature is more controversial about the impact of staple line reinforcement materials. A meta-analysis by Gagner et al. including 88 studies and 8920 patients showed that fistula and bleeding rates are significantly reduced when using glycolide copolymer as reinforcement compared to other types of reinforcement, staple line oversewing or the absence of reinforcement.[28] In a recent update, Gagner et al. reported a leak rate of 0.67% when the glycolide copolymer reinforcement was used.[29] Stroh et al. reported that the risk of leak was maximal when reinforcement and oversewing were associated.[13] A more recent study by Berger et al. reported that the use of staple line reinforcement significantly increased the risk of leak (0.96% vs. 0.65%, odds ratio: 1.20 95% CI: 1.00–1.43).[24] Although this study was retrospective and simply observational in its nature, the authors’ conclusions are those that only a well-conducted randomised trial would allow. Furthermore, this study lacks important information on the type of cartridge, stapler, type of reinforcement, type of suture, clip, glue and many other surgical details that may play an important role in the occurrence of a staple line leak.[30] The methods used in this study have also been highly criticised. Indeed, a model of intention to treat analysis based on surgeon level information is built to capture cases where anatomical or technical factors leading a surgeon to perform additional manoeuvres to prevent problems such as the staple line reinforcement and/or suture. However, this resulted in the splitting of the initial population in many categories reducing the power of the statistical analysis.[31]

Portal thrombosis

Portal thrombosis is a rare complication of SG occurring in approximately 0.3% of cases.[32] Several mechanisms are evoked including splenic ischaemia, post-operative dehydration, exposition of the splenic vein and its close contact to the stapling line and/or deep fluid collection, the variation in blood flow following section of the vessels from the greater curvature and thrombophilia syndromes. Traumas to the left liver lobe by retractors were evoked by some authors, but it cannot be explained why portal thrombosis is far rarer after the other bariatric procedures demanding liver retraction such as GB.[32]

Management of post-operative complications

Most authors agree concerning the interest of a temporary discontinuation of anticoagulation treatment. Patients who are haemodynamically unstable as well as those with an important intraperitoneal haematoma are candidates for surgery. Surgical exploration allows blood clots evacuation and eventually the identification and treatment of the bleeding source. Evacuation of the hematoma simplifies the post-operative course because spontaneous resorption is longer and needs monitoring. Furthermore, the hematoma can open into the stomach through the staple line and/or get infected secondarily. In case of intraluminal bleeding at the staple line that persists after conservative treatment, endoscopy can achieve haemostasis. In case of endoscopic failure or impossibility to perform endoscopy, haemostasis can be achieved by oversewing the whole staple line with running sutures.

Endoscopy with balloon dilatation is often sufficient to dilate a localised stricture of the gastric tube even if multiple sessions are generally necessary.[2033] An endoscopic stent can be placed in case of recurring strictures resistant to endoscopic dilatations. In case of failure, conversion into GB is the standard surgical option.[34]

Leak

More than 50% of leaks show clinical signs within 10 days from surgery, often when the patient has already been discharged.[2125] Leaks are classified according to the timing of clinical signs because of its impact on their management: early (within 2 weeks), intermediate (between 2 and 6 weeks) and late (after 6 weeks).[35]

Tachycardia (>120 bpm) represents the most important clinical sign indicating the need for reoperation. The association of tachycardia, fever and tachypnea has a high positive predictive value for a leak. These clinical signs are also evocative of pulmonary embolism and generally lead to perform a CT scan. Abdominal examination is often poorly informative but signs of peritoneal irritation can sometimes be present. In case of early leaks an emergency reoperation is mandatory. Laparoscopy is often feasible and must include a thorough peritoneal washing associated to the placement of a drain at the level of the leak. A feeding jejunostomy is not systematic. Suturing the leak orifice is systematically unsuccessful and is therefore not recommended. Once the leak has been effectively drained, therapeutic management is based on one side on appropriate nutrition, control of the sepsis, nil by mouth and on local treatment of the leak on the other side, usually by endoscopy.

Management of intermediate leaks is different because a reoperation is followed by a higher mortality (up to 10%) and 50% morbidity and necessitates in half of the cases a conversion to open surgery.[35] A conservative treatment is most often done, with either radiologic or endoscopic drainage of the collection, associated to a targeted antibiotic therapy, nil by mouth with either a parenteral nutrition or an enteral nutrition through a nasojejunal tube. Endoscopic treatment permits healing of intermediate leaks in about 90% of cases within 5 weeks.[3536] Success of conservative treatment varies between 40% and 80% in series reporting late leaks.[35] Concerning endoscopic treatment, several options are available, which can be combined, including: the use of stents to cover the leak, the drainage of the leak-related intrabdominal collection into the gastric lumen and the direct closure of the leak orifice.[373839404142] The strategy depends on the endoscopic expertise of the bariatric team, characteristics of the leak and presence of eventual gastric stenosis. The size of the leak orifice plays a major role: in case of a small orifice leak (diameter <1 cm), the treatment of choice consists in the drainage of the cavity into the gastric lumen through one or multiple double pigtail drains (DPDs); if leak orifice is larger (>1 cm), a stent is placed to cover the wall defect.[39]

Recently, long endoscopic stents have been created specifically for the stomach. The main indication for stent placement is a leak with large orifice (>1 cm) associated to the presence of a stricture beneath the leak.[3839] The scope of the stent is to cover a wide communication, allow oral feeding as well as the ‘home management’ of the patient. Endoscopic stent must be placed as soon as possible once surgical or radiologic drainage of the leak has been achieved. Endoscopy also permits to perform the debridement of the abscess cavity around the leak.

Drainage by DPD can be performed once the collection and/or fistula tract is no more in communication with the rest of the peritoneal cavity. The main advantage is the absence of percutaneous drainage reducing the need for patient's care and therefore increasing patient's comfort.[404142] The intraluminal drainage also reduces the risk for the fistula tract to reach the skin, creating a gastrocutaneous fistula which is hard to treat conservatively. DPD is removed after healing of the collection. The residual orifice communicating with a blind cavity can be either closed with an OVESCO endoscopic clip or its edges revive to facilitate healing.

Leaks persisting >4 months despite a well-conducted conservative treatment are considered as chronic and are very unlikely to heal without surgery. Two main options exist: the first is fashioning a Roux-en-Y eso-jejunostomy associating a gastrectomy of variable extension,[43] while the second is the apposition of a Roux-en-Y limb as a patch over the fistula defect. Esojejunostomy can be performed earlier because the abdominal esophagus can be easily identified above the inflammatory area. To fashion a safe anastomosis, the transection must be performed above the fistula orifice, usually at the level of the esophagus or even at the level of the proximal stomach, leaving a small gastric stump when possible.[44] The gastric sleeve below the anastomosis can be completely resected or a remnant of the body and antrum below the leak orifice can be left in place (determining a proximal, total or subtotal gastrectomy).[43] The apposition of a Roux-en-Y limb as a patch has the advantage of maintaining the gastric sleeve and can be even technically easier providing a sufficient time interval for acute inflammation to be over. Nevertheless, regression of gastric inflammation can take a relatively long time. Rosenthal et al. advocated a minimum delay of 12 weeks between the initial management and an eventual reoperation for the treatment of a leak.[45] The key technical point is to approach the abdominal esophagus from the right, as in the case of an anti-reflux surgery. This allows the exposure of the fistula tract that is always situated on the left side of the EGJ. The second technical point concerns the management of the fistula orifice that should not be enlarged since the easiest option consists in patching the Roux-en-Y loop over the fistula orifice on a length of 5–7 cm without mucosa-to-mucosa anastomosis.[44]

Clinical presentation can be dramatic with digestive ischaemia needing surgical exploration or less important with only abdominal pain. CT scan usually leads to diagnosis, while Doppler ultrasound allows monitoring the evolution. Treatment depends on clinical severity and includes rehydration and fasting. If an abdominal collection is found, drainage and targeted antibiotic therapy are recommended. Anticoagulation therapy must be started as soon as possible either by subcutaneous low molecular weight heparin (1.5–2 mg/kg/day in two injections) or by intravenous continuous infusion of heparin (target thromboplastin time 60–90 s). After the early phase, treatment can be switched to oral anticoagulants (target INR between 2.5 and 3) to be maintained for 3–6 months. Anticoagulation allows thrombosis regression in most of early-diagnosed cases, preventing from pre-hepatic portal hypertension.[46] Surgery is reserved to complications of thrombosis such as digestive ischaemia with necrosis.

CONCLUSION

SG has known an incredible rise in popularity during the last decade. Despite the multiple advantages, it may result in severe complications. The staple line leak at the EGJ is the most feared complication and its prevention remains difficult, as the involved mechanisms have been only partially elucidated. Its management is long and requires a multidisciplinary technical platform including Intensive Care Unit, digestive endoscopy and interventional radiology as well as a specialised surgeon.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.