Not accounting for the manufacturing defects of the actual stapling device, the rest of the staple line misfiring is due to incorrect choices or inappropriate use of the device itself. The key elements in avoiding these problems are adequate choice of cartridge staple heights (especially if buttressing material is used), avoidance of bunched up tissue within the jaws of the stapler, careful evaluation of the crossing of staple lines, and appropriate tissue compression time. In general, all the staple lines should be carefully evaluated, and when in doubt, redo stapling or oversewing should be implemented.

Intraoperative air leak test of the Gastrojejunal anastomosis is currently considered the standard of care during gastric bypass surgery. The different types of leak test include pneumatic (either by gastric tube or endoscope) or blue dye (usually methylene blue).

As previously described by others, the reproducible air leak is the one that requires intervention [2]. If the actual location of the air leak is clearly recognized, suture closure with adjuncts of omental patch or fibrin glues or sealants is acceptable. However, if the site is not clearly identifiable, or the former intervention is ineffective, redoing the anastomosis is mandatory. Furthermore, drainage of the area should be considered even by surgeons who do not routinely drain anastomosis. Under these circumstances the need for remnant gastrostomy tube should be individualized, and it should be considered in the reoperative cases. Also, it is the authors’ strong belief that a postoperative upper gastrointestinal (GI) study is beneficial in this scenario both from a clinical and medical legal standpoint.

Most of these perioperative peripheral neuropathies are due to traction or compression injuries at the time of patient positioning in the operative table. The most common locations are the brachial plexus (overextension of the arms on the arm boards), ulnar neuropathy (from compression at the elbow), and lower extremities neuropathy. The main symptom is usually paresthesia. The mechanism of nerve injury is usually neuropraxia, due to the injury to the endoneurial capillaries with resulting edema and conduction block. Since there is no degeneration of the axon, the return of sensation is rapid and usually complete within 1 week or less. When the trauma is more significant and causes segmental demyelinization, the functional recovery occurs within few months.

A rare but typical peripheral neuropathy is meralgia paresthetica [3]. This is caused by the compression of the lateral cutaneous nerve against the inguinal ligament. Symptoms vary from hypersensitivity and paresthesia to pain in the lateral anterior aspect of the thigh. This typically occurs after laparoscopic procedures and tends to resolve spontaneously with conservative treatment. Occasionally a local nerve block may be helpful in reducing symptoms.

Rhabdomyolysis is a syndrome caused by injury to the skeletal muscle. In most cases the pathogenesis is due to ischemia-reperfusion syndrome causing sarcolemmal damage of the skeletal muscle and resulting in the release of proteins and renal tubules damage. Besides the well-known acute renal insufficiency, RML can cause severe hyperkalemia, hypocalcemia, compartment syndrome, disseminated intravascular coagulation, cardiac arrhythmias, and even death. Its incidence has been reported between 12.9 and 37.8 % [4]. Contributing risk factors for the development of RML are male gender, higher BMI (>50 kg/m²), current therapy with statins, operative time >4 h, and the use of propofol injection. Propofol infusion syndrome is very rare, but it is more frequent in obese patients due to the lipophilic characteristics of the drug. Careful padding of all pressure points, early patient mobilization, and reduction of operating room time can contribute to the prevention of this syndrome. The diagnosis is both clinical and biochemical (increased CPK levels five times higher than the normal and the presence of myoglobin in the urine). The treatment is mostly supportive with aggressive fluid resuscitation, correction of electrolytes abnormalities, and, in some cases, alkalinization of the urine.

Other common early complications related to anesthesia and the medical aspects of obesity, such as cardiac complications, venous thromboembolic events, hypoxia/hypercarbia, hyperglycemia, and hypertensive crisis, are outside the scope of this chapter and will be addressed elsewhere.

Leaks remain the second leading cause of death after RYGB surgery. Potential sites of leaks include the Gastrojejunal anastomosis, gastric pouch, gastric remnant, the jejunal blind end, and the Jejunojejunal anastomosis. Approximately 70–80 % of the leaks occur at the Gastrojejunal anastomosis, 10–15 % at the gastric pouch, 5 % at the Jejunojejunal anastomosis, and 3–5 % at the excluded stomach. Factors involved in the development of these leaks include tension, ischemia, and staple misfiring. Different techniques have been described for the Gastrojejunal anastomosis using a circular stapler, linear stapler (with stapled or hand-sewn closure of the anterior wall), and completely hand sewn. The available data comparing the techniques has never been able to convincingly show the difference in leak rates of the three techniques. A recent collaborative study showed an increased incidence of hemorrhage and wound infection with the circular stapled technique [5]. The other variable potentially involved in the degree of tension on the anastomosis is the route of the Roux limb. Although it is true that the retrocolic-retrogastric route is the shortest one, leak rates between this technique and the antecolic-antegastric one have not been definitively proven to be different. Only one study was able to demonstrate a significant difference with higher leak rates of the antecolic (3 %) versus the retrocolic (0.5 %) [6]. Some of the risk factors associated with higher incidence of leaks include male gender, super morbid obesity, age >55 years, and revisional procedures [6].

Unquestionably, an early diagnosis and treatment significantly affects the patient outcome, not only in terms of hospital, and in particular ICU stay, but also in terms of survival. It is then important to have a degree of suspicion, even when the workup remains negative. Common, but not uniformly present, signs and symptoms of leak include sustained tachycardia, abdominal pain, fever, nausea and vomiting, oliguria, hemodynamic instability, and sense of impending doom. The diagnosis can be obtained or confirmed by radiographic modalities such as contrast upper gastrointestinal fluoroscopic evaluation (UGI) or CT scan. Although the specificity of the UGI is very high for GJ leaks, its sensitivity is only in the 20 % range [7]. CT scan adds sensitivity to the diagnosis of GJ leaks because of the ability to show not only contrast extravasation and extraluminal collections but also indirect signs of leak, such as surrounding inflammatory changes, intra-abdominal free air, and left pleural effusion. Also, the CT scan is able to show additional sites of potential leaks, such as the gastric remnant, JJ anastomosis, gastric remnant distention, etc. Occasionally, the diagnosis of leak is made by the character of the fluid obtained from the intraoperative drain. In these circumstances a specific, but not sensitive, adjunct diagnostic modality is the use of oral dye, such as methylene blue.

The goals of treatment are antibiotic treatment, bowel rest, control of secretions, wide drainage, and early nutrition. Although the standard means of obtaining these goals is by operative intervention, the hemodynamic status of the patient and the time of occurrence of the leak might dictate a nonoperative approach. During the operative approach, the key steps include extensive irrigation; repair of the leak, if feasible and safe; placement of enteral access distal to the leak site; and extensive closed suction drain placement. Based on the surgeon’s individual skills and experience, these steps can be either accomplished laparoscopically or via an open approach. Whenever the patient’s hemodynamic status allows, the local sepsis control can be accomplished via percutaneous drainage or with the drains previously placed at the time of surgery. It is important in these cases to continue to monitor symptom progression, as failure of nonoperative treatment has been reported in 12 % of the cases [7]. Regardless of the approach utilized, the mortality of a leak remains high (10 %) [8].

Gastrogastric fistula (GGF) refers to an abnormal communication between the excluded gastric pouch and the gastric remnant. The incidence of GGF varies between 0 and 46 % in the literature [9]. In our own experience, the incidence has been 1.2 % [10]. Overall the incidence of GGF, similar to other complications after gastric bypass, has been steadily decreasing. Reasons for the dramatic reduction include better instrumentation, improved techniques, and increased experience among surgeons performing these procedures.

Common presenting symptoms include nausea, vomiting, and epigastric pain, which are present in approximately 80 % of patients. Up to 53 % of patients will have a marginal ulcer or a complication of it (bleeding, perforation) as presenting symptoms. Another subset of patients will present with failure of weight loss or weight regain. The latter category of patients, upon further questioning, always report some element of nausea or vomiting, epigastric pain, or a history of marginal ulcers.

The time of onset and location of GGF vary significantly depending on etiology (Table 2). In fact, GGF can be classified into 6 categories based on their etiology [11], including the following:

The diagnosis of GGF is usually based on symptoms and confirmed either by endoscopy or upper GI study. The upper endoscopy is unfortunately positive in approximately half of the patients. The most sensitive test, however, remains the upper GI study. This is commonly performed in different patient’s positions, including decubitus. Additional information can also be obtained by an abdominal CT scan, such as gastric remnant distention with gas and contrast.

The initial treatment is medical and consists of protein pump inhibitors, with the addition of sucralfate in case of a documented concomitant ulcer. The aim of the treatment is to reduce the acid production in the gastric remnant, which is now enhanced by the presence of food. In the presence of a marginal ulcer responding to medical therapy and in the absence of additional symptoms, observation and reevaluation in 6 weeks is acceptable. The minority of patients that do not respond adequately to medical treatment and present with weight regain or failure of weight loss will require additional interventions. Some authors advocate endoscopy as a first-line therapeutic intervention, claiming no increased complication if a future revisional surgery is necessary [12]. Unfortunately, although often technically feasible, endoscopic closure has a very high recurrence rate. The success rate is inversely proportional to the diameter of the fistula itself. Fistulae larger than 1 cm have a much less chance of remaining closed after endoscopic treatment. Endoscopic techniques include injection or fibrin glue, plasma coagulation, clipping, stenting, and various endoscopic suturing techniques.

A much more effective treatment, although more invasive, is surgical intervention. The type of approach is dictated by the type of fistula. It is important to not only address the anatomic abnormality but also to understand the physiologic derangement, if any, that led to the fistula in the first place. In the case of acid hypersecretion and chronic marginal ulcer, pouch trimming and redo Gastrojejunostomy are fundamental. In the case of refractory marginal ulcer with proven acid hypersecretion in the pouch, a truncal vagotomy might be added. Remnant gastrectomy has also been advocated by our group as a treatment option for GGF [12]. In the cases of fistulae related to the failure of separation of the remnant from the gastric pouch, simple stapling across the previously undivided gastric bridge will be appropriate. This is especially true when the fistula is not in proximity of the Gastrojejunal anastomosis. A thorough knowledge of the anatomy of the previous gastric bypass, as well as a review of the previous operative reports, helps in strategizing the surgical approach. Whenever Gastrojejunal anastomosis resection has to be carried out, it is important to have information about the length of the Roux limb and its location in relationship to the stomach and colon. In fact, resecting the pouch and the anastomosis without having enough Roux limb length to achieve a tension-free new anastomosis will require revision of the Jejunojejunostomy to a more distal position as well. It is then important to have a thorough preoperative evaluation both by EGD and upper GI study to acquire as much information as possible concerning the gastric pouch size, the anastomotic status, and the Roux limb length.

Postoperative hemorrhage has been reported in 1.9–4.4 % of gastric bypass procedures [13]. The bleeding could be either intraluminal or extraluminal, and it usually originates from the staple lines of the GJ or JJ anastomosis, gastric remnant, or gastric pouch. Although some mostly retrospective studies showed decreased incidence of postoperative bleeding with staple line reinforcement, a recent meta-analysis of three randomized trials reports no difference in bleeding episodes [14]. It is important to use standardized postoperative protocols to avoid system errors and automatic DVT prophylaxis anticoagulation administration before a full patient assessment. The signs and symptoms vary based on the entity of the bleeding from mild tachycardia to signs of hypovolemic shock with hypotension and oliguria. It is important to remember that intraluminal bleeding can also determine intestinal obstruction and devastating complications (anastomotic leak, gastric remnant perforation) even if the bleeding is self-limiting. Whenever intestinal obstruction is suspected, imaging studies with upper GI contrast study and CT scan are warranted. Although most of the immediate postoperative hemorrhages are self-limiting and can be managed with blood product transfusion, stopping anticoagulation, and aggressively correcting coagulation derangements, the presence of hemodynamic instability or the continuous requirement of blood transfusion is an indication for immediate intervention. In the early postoperative period, the role of endoscopy for the evaluation of intraluminal bleeding is limited to the evaluation and potential treatment of the Gastrojejunal anastomosis. More aggressive endoscopic procedures (enteroscopy and double-balloon enteroscopy) to evaluate Jejunojejunostomy and gastric remnant should be reserved for late postoperative bleeding. Whenever endoscopic intervention is not feasible or appropriate, operative intervention should not be delayed. The hemodynamic status of the patient along with the surgeon’s comfort level will determine if a laparoscopic or laparotomic approach is chosen. Often the intra-abdominal source of bleeding is not found, but hematoma evacuation and washout expedites the patient’s recovery. In the presence of an intraluminal bleeding source, the affected anastomosis can be approached directly or intraluminally via an adjacent enterotomy.