History of the Procedure
The operations most commonly associated with this complication include distal or subtotal gastrectomies for peptic ulcer disease or gastric malignancies with Billroth II reconstructions, pancreaticoduodenectomies, and gastrojejunostomies performed to bypass other foregut pathology. The pathophysiology and signs and symptoms associated with ALS result from partial or complete obstruction of the afferent loop.
ALS is included in the constellation of resectional gastric surgical complications known as the postgastrectomy syndromes. The following syndromes are included:
- Early dumping syndrome
- Late dumping syndrome
- Postvagotomy diarrhea
- Chronic gastric atony
- Roux stasis syndrome
- Small gastric remnant syndrome
- Alkaline reflux gastritis
- Afferent loop syndrome
- Efferent loop syndrome
Patients with ALS may present with an acute, completely obstructed form or with a chronic, partially obstructed form. The syndrome can manifest at any time from the first postoperative day to many years after surgery. The acute form usually occurs in the early postoperative period (1-2 wk), but it has been described to occur 30-40 years after surgery.
In 1942, McNealy first described acute ALS as a cause of early postoperative duodenal stump leakage. Lake is credited with recognizing the chronic form in 1948. Roux and coworkers coined the term afferent loop syndrome in 1950. The first detailed exegesis in the English literature on the etiology, clinical presentation, and treatment of ALS was contributed by Wells and Welbourn in 1951.
Problem
ALS manifests in acute and chronic forms. Acute ALS represents complete obstruction of the afferent loop and is a true surgical emergency. It must be diagnosed and corrected expeditiously. Chronic ALS is associated with partial obstruction. It is not a surgical emergency but does require corrective surgery.
Frequency
In the United States, ALS affects approximately 1% of patients undergoing gastric resection and Billroth II gastrojejunostomies. This figure may be an underestimation because this complication is probably underdiagnosed. Overall, the incidence of this complication decreased dramatically during the final quarter of the 20th century as elective gastric surgery for complications of peptic ulcer disease underwent a logarithmic decline.
Internationally, rates for the development of this complication appear to be similar in other nations.
Mortality/Morbidity: Mortality rates of up to 57% have been reported for acute ALS. Mortality is most frequently associated with a delay in diagnosis that leads to bowel infarction or rupture and peritonitis. Patients in whom a timely diagnosis is made or who present with chronic manifestations of the disease can undergo corrective surgery with acceptably low morbidity and mortality rates.
Sex: According to Tovey et al, one or more of the postgastrectomy syndromes is more likely to occur in female patients.
Age: ALS favors no particular age group on a per capita basis.
Etiology
Postoperative conditions
Each of the following postoperative conditions can cause ALS in a patient with a gastrojejunostomy:
- Entrapment or compression of the afferent loop by postoperative adhesions
- Internal hernia (eg, through a mesocolic defect)
- Volvulus of the intestinal segment
- Enteroenteral or enterogastric intussusception
- Kinking of the afferent limb at the gastrojejunostom
- Scarring due to marginal (stomal) ulceration
- Recurrence of cancer at or near the anastomotic site
- Enteroliths in the afferent limb
- Bezoars in the afferent limb or at the anastomosis
- Foreign bodies in the afferent limb or at the anastomosis
Surgical technique
Patients have an increased chance of developing ALS if one or more of the following conditions is met:
- The jejunal portion of the afferent limb is longer than 10-15 cm
- The gastrojejunostomy is placed in an antecolic position instead of a retrocolic position.
- Mesocolic defects are not properly closed after construction of a retrocolic gastrojejunostomy.
Bushkin and Woodward reported an equal incidence of ALS in patients with short, retrocolic afferent limbs. However, according to Eagon and coworkers, most authors opine that longer, redundant, and antecolic afferent limbs are more prone to kinking, volvulus, and entrapment by adhesions.
Pathophysiology
An afferent loop is composed of the duodenal stump, the remainder of the duodenum, and the segment of jejunum located proximal to a Billroth II–type gastrojejunostomy. ALS is caused by complete or partial mechanical obstruction at the gastrojejunostomy or at a point along the jejunal portion of the afferent loop.
Passage of food and gastric secretions through the gastrojejunostomy and into the efferent loop triggers release of secretin and cholecystokinin. These enteric hormones stimulate secretion of bile, pancreatic enzymes, and pancreatic bicarbonate and water into the afferent loop. Under gastrointestinal hormonal influence, up to 1-2 L of pancreatic and biliary secretions can enter the afferent loop each day.
Symptoms associated with ALS are caused by increased intraluminal pressure and distension due to accumulation of enteric secretions in a partially or completely obstructed afferent limb. ALS is one of the main causes of duodenal stump blowout in the early postoperative period and is also an etiology for postoperative obstructive jaundice, ascending cholangitis, and pancreatitis due to transmission of high pressures back to the biliopancreatic ductal system. High luminal pressures and distension increase bowel wall tension in the afferent loop (in accord with the Laplace law) and can lead to ischemia and gangrene with subsequent perforation and peritonitis.
Secondarily, prolonged stasis and pooling of secretions with partial obstruction facilitate bacterial overgrowth in the afferent loop. Bacteria deconjugate bile acids, which can lead to steatorrhea, malnutrition, and vitamin B-12 deficiency. Iron deficiency can occur because of bypassing of the proximal small bowel.
The severity at presentation mainly depends on the degree and duration of obstruction.
Clinical
History
Acute ALS
Acute ALS is caused by complete obstruction of the afferent loop. Patients with acute ALS typically present with a sudden onset of epigastric and/or right or left upper quadrant abdominal pain, with associated nausea and vomiting.
With acute ALS, the vomitus is not bilious because the biliary and pancreatic secretions remain trapped in the obstructed bowel loop. If the afferent loop is not decompressed, the patient becomes acutely ill and can subsequently develop peritonitis and shock if intestinal perforation or infarction ensues.
Chronic ALS
Chronic ALS is caused by partial obstruction of the afferent loop. Approximately 10-20 minutes to an hour postprandially, the patient experiences abdominal fullness and epigastric pain. These symptoms usually last from several minutes to an hour, although they occasionally last as long as several days.
Projectile bilious vomiting is a classic manifestation of ALS with partial obstruction. The distended afferent loop decompresses forcefully, providing rapid relief of symptoms. Note that the vomitus usually contains no food because it has progressed along the unobstructed efferent limb. Vomiting may occur after each meal or only occasionally. Also, symptoms in the immediate postprandial period may be minimized if the patient assumes a recumbent position.
Prolonged chronic ALS with stasis and bacterial overgrowth can be further complicated by steatorrhea, diarrhea, and vitamin B-12 deficiency anemia. These effects are primarily due to bacterial deconjugation of bile salts. The aforementioned factors, in addition to bypassing the duodenum and proximal jejunum, can result in iron deficiency anemia.
PhysicalPhysical examination can reveal one or more of the following findings:
- An ill-defined mass in the right upper abdominal quadrant
- Localized midepigastric or right upper abdominal quadrant tenderness
- Peritonitis and/or a rigid abdomen if necrosis or perforation of the bowel wall has occurred
- Jaundice
- Signs of pancreatitis (eg, upper abdominal pain radiating to the flank or back
Differential diagnoses
- Abdominal abscess
- Abdominal hernias
- Acute mesenteric ischemia
- Anemia
- Bacterial overgrowth syndrome
- Benign gastric tumors
- Benign neoplasm of the small intestine
- Bile duct strictures
- Bile duct tumors
- Biliary colic
- Biliary obstruction
- Carcinoma of the ampulla of Vater
- Choledochal cysts
- Choledocholithiasis
- Esophagogastroduodenoscopy
- Gastric outlet obstruction
- Gastric sarcoma
- Gastric ulcers
- Gastric volvulus
- Gastritis (acute, atrophic, or chronic)
- Intestinal perforation
- Mesenteric artery ischemia
- Mesenteric artery thrombosis
- Mesenteric tumors
- Omental torsion
Other problems to be considered
- Bile reflux gastritis
- Pancreatic pseudocyst or cystic tumor
- Mesenteric cyst
- Mesenteric lymphoid hamartoma
- Intra-abdominal abscess
- Cystic metastases
Medical therapy
Acute ALS
In patients with acute ALS, a favorable outcome is correlated with an expedient diagnosis and corrective surgery. Medical therapy has no role.
Chronic ALS
Patients with chronic ALS can be severely malnourished and anemic. They may benefit from preoperative specialized nutritional support or transfusion before undergoing corrective surgery. However, do not delay surgery if signs and symptoms consistent with complete obstruction develop.
Surgical therapy
The treatment of ALS is surgical. Conservative measures can be temporarily used to resuscitate the patient, but the definitive treatment is corrective surgery. When ALS is caused by recurrent or unresectable malignancies, successful palliation is frequently accomplished using interventional radiologic techniques. Several references are described in the preceding section.
Surgical correction is effected by deconstructing the Billroth II gastrojejunostomy and restoring gastrointestinal continuity with an alternate method. Several procedures have been described, but the 2 predominant operations are Billroth I gastroduodenostomy and Roux-en-Y gastrojejunostomy.
Vettoretto and associates reported a case of afferent loop obstruction caused by an adhesive band following distal gastrectomy and reconstruction for gastric cancer. The authors performed diagnostic laparoscopy and laparoscopic lysis of adhesions, resulting in resolution of the ALS.
Aimoto and colleagues described 2 cases of malignant ALS in patients who had undergone pancreaticoduodenectomy. In both patients, recurrence of pancreatic cancer was found at laparotomy. Bypass procedures were performed in each case to effect palliation.
Consultations: Early consultation with a surgeon is mandatory.
Preoperative details
The patient is properly identified. The patient (or a legal representative) is counseled about the operation and signs the informed consent documents.
Intravenous access is established, and intravenous fluid resuscitation is begun. A nasogastric tube is placed to decompress the stomach, and preoperative antibiotics are administered.
Intraoperative details
Billroth I gastroduodenostomy
This procedure creates a direct anastomosis between the stomach and duodenum. It is the most physiologic procedure and is therefore the operation of choice. Several factors may preclude its use, including previous subtotal gastrectomy or extensive scarring around the duodenum. In these situations, the surgeon may be unable to gain enough mobility on the stomach and duodenum to create an anastomosis without excessive tension.
Roux-en-Y gastrojejunostomy
For a Roux-en-Y gastrojejunostomy, the jejunum is divided several centimeters distal to the ligament of Treitz. The proximal portion of the distal jejunal segment is anastomosed to the stomach. The distal end of the Roux limb is anastomosed to the distal jejunal segment. This jejunojejunostomy is created approximately 40 cm downstream from the gastrojejunostomy in order to minimize the possibility of developing alkaline (bile) reflux gastritis.
Van Stiegmann and Goff described a variant of this operation in which the jejunum is not divided. This is the so-called uncut Roux-en-Y gastrojejunostomy. The procedure was developed to avoid Roux stasis syndrome, which was thought to be caused by interruption of jejunal intestinal pacesetting potentials.
In an uncut Roux procedure, a loop gastrojejunostomy is fashioned. The afferent limb of this loop is occluded—but not divided—by a staple line. A jejunojejunostomy is made between the afferent and efferent jejunal limbs just proximal to the occluding staple line. This operation has not gained wide acceptance, partially because of the problem of dehiscence of the occluding staple line, as reported by Mulholland and colleagues.
Other surgical procedures
The following remedial operations have also been used:
- Revision of the gastrojejunostomy
- Side-to-side enteroenterostomy
- Jejunal segment interposition (between the gastric remnant and duodenum to create a modified Billroth I–type anastomosis)
- Resection of the redundant portion of the afferent jejunal loop
Postoperative details
Further inpatient care
Intravenous fluids
Resuscitative and maintenance intravenous fluids are provided postoperatively. These are usually administered as a balanced salt solution (eg, lactated Ringer solution). If the patient has hypochloremic metabolic alkalosis due to nasogastric suctioning or other causes, normal saline can be substituted. Intravenous fluid support is continued until the patient successfully resumes oral intake.
Activity
Early activity, including arising from the bed to a chair and ambulating frequently, is encouraged.
Diet and nutrition
Patients are kept nil per os (NPO) for varying durations depending on the preference of the operating surgeon. Because correction of ALS entails reoperative gastric and small bowel surgery, many surgeons choose to advance patients slowly.
Following nasogastric tube removal, patients can be started on liquids and advanced to a full diet as tolerated. Postgastrectomy diet counseling by a registered dietitian is helpful. Patients may find that they tolerate 5-6 smaller feedings per day better than the traditional 3 meals.
Depending on the patient's preoperative nutritional status, a period of specialized nutritional support might be warranted. This can range from enteral tube feedings to peripheral hyperalimentation to total parenteral nutrition. In addition, multivitamin and iron supplementation may be indicated.
Drains
A nasogastric tube is typically left in place postoperatively. Ensuring that the tube functions continuously and remains unclogged is crucial. Criteria for removal of a nasogastric tube include diminishing output and return of bowel function as manifested by bowel sounds or the passage of flatus.
A Foley catheter remains in place in the early postoperative period to monitor hydration status and to serve as a guide for fluid resuscitation. Once the patient is stabilized and no further major fluid shifts occur, the catheter can be removed.
Pulmonary toilet
Instruct patients to cough and to take frequent deep breaths. The incentive spirometer is an important adjunct and should be used every 1-2 hours while the patient is awake. Early mobilization of the patient assists with maintaining good pulmonary toilet.
Monitoring
Vital signs are monitored per protocol. Intake and output records are kept to monitor intravenous fluids given, oral intake, and urine and nasogastric tube outputs. Pulse oximetry may be used to measure oxygen saturation.
Antibiotics
Unless bowel perforation has occurred, a single dose of antibiotics as prophylaxis against wound infection usually suffices. Patients with abdominal catastrophes, such as bowel perforation or infarction, require a full course of antibiotic therapy aimed at gut flora.
Pain control
An epidural catheter can be placed by anesthesia personnel for postoperative pain control. Alternately, a patient-controlled anesthesia regimen can be ordered.
Deep venous thrombosis prophylaxis
Prophylaxis against deep venous thrombosis is crucial because deep venous thrombosis and pulmonary embolism are significant sources of postoperative morbidity and mortality. Available modalities include subcutaneous heparin, subcutaneous fractionated heparin preparations, and sequential compression stockings.
Aspiration precautions
The head of the bed can be kept elevated at 30-45° or sometimes higher in elderly patients or during sleep.
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