Gastrojejunostomy

Anatomy and Physiology

Anatomy and Physiology of the Stomach

The stomach is a well-vascularized organ that resides in the left upper quadrant of the abdomen; the stomach starts just below the diaphragmatic hiatus where the esophagus enters it at the gastroesophageal junction. This most proximal part of the stomach is known as the cardia and gives rise to the main body of the stomach as well as the fundus, which is the floppy, distensible superior most portion of the stomach. The parts of the stomach distal to the body are the antrum followed by the pylorus, which enters the duodenum. The greater omentum is attached to the inferior border of the stomach along the greater curvature and hangs down over the viscera below. The lesser omentum makes a connection between the stomach and the liver and is also known as the gastrohepatic ligament.

The stomach has a robust blood supply from the branches of the celiac trunk and even has a collateral flow from the superior mesenteric artery via the gastroduodenal arteries. The venous drainage is through left gastric and right gastric draining into the portal vein, the left gastroepiploic draining into the splenic vein, and the right gastroepiploic vein draining into the superior mesenteric vein. The stomach is innervated by both the right and left vagus nerve and also has a robust lymphatic drainage system. Given the proximity of the stomach to such vital structures as the pancreas, portal triad, aorta, inferior vena cava, and spleen, to name a few, any surgeon operating on the stomach must have a full understanding of all of these anatomic structures to perform a gastrojejunostomy safely.[5]

The physiology of the stomach involves a complex interplay of hormonal and neural messengers to regulate the stomach's motility, distensibility, and acidity, and a full summary of the entire physiology of the stomach is beyond the scope of this article.[5] There are a few key points worth covering more closely, although any healthcare provider planning to operate on the stomach should have a full understanding of its physiology.

Firstly, the antrum of the stomach contains the G cells, which produce the hormone gastrin, which increases acid production when the pH in the stomach is too high. If there is retained antrum after resection of the stomach, the antral G cells are separated from the parietal cells in the stomach remnant and bathed in alkali fluid from the duodenum. This high pH environment causes them to secrete excess gastrin, which in turn causes the stomach remnant to produce excess acid, leading to ulceration.[6]

Secondly, the stomach digests food into a nutrient-rich chyme, which then passes into the duodenum for further digestion. Disrupting the natural flow of the nutrients so that they deposit directly into the jejunum can lead to dumping syndrome, which will be discussed further in the complications section.[7]

Thirdly, the acid produced by the stomach is typically neutralized by basic pancreaticobiliary secretions in the duodenum. When the stomach and the jejunum are directly connected, this neutralizing environment is bypassed and predisposes the jejunal area closest to the stomach to develop ulcers.[8]

Anatomy and Physiology of the Jejunum

The jejunum starts at the ligament of Trietz and extends for approximately 250 cm before transitioning into the ileum. Its blood supply comes from the superior mesenteric artery. Its venous drainage is via the superior mesenteric vein. The jejunum contains few Brunner glands, which are chiefly found in the duodenum, and few Peyer patches, which are primarily found in the ileum. The jejunum is the site where the highest amount of absorption of nutrients and vitamins takes place except iron, which is chiefly absorbed in the duodenum and vitamin B12, which is absorbed in the terminal ileum. The jejunum is primarily lined with enterocytes and has long villi, which increase its surface area, which can be used for absorption. The motility of the jejunum is regulated by vagal stimulation, migrating myoelectric complexes, and the hormone motilin.[9]

Indications

There are three main indications to perform a gastrojejunostomy:

• It can be performed to bypass an obstruction of the distal stomach or proximal small bowel such as in the setting of cancer or scarring from an ulcer or other cause.[10]
• It can be performed to bypass much of the small intestine as part of a weight-loss procedure, as is the case when a Roux-en-Y procedure is performed.[11]
• It can be performed as part of a reconstruction procedure after subtotal gastrectomy for cancer.[12]

Contraindications

The only contraindication to performing a gastrojejunostomy is when the procedure cannot be safely performed, or the odds of anastomotic leak is very high.

The procedure is unable to be performed safely in the setting of extensive adhesions, massive ascites, abdominal carcinomatosis, extensive gastric varices, or if the anatomy is very altered from previous procedures. These are all relative contraindications, and it is up to the attending surgeon to determine if the procedure can be performed with less severe complications in the setting of these issues.

The primary reason for an unacceptably high risk of an anastomotic leak is malnutrition, particularly in patients that have gastric malignancy or ulcers. If there is a concern for malnutrition in a patient that requires a gastrojejunostomy, then nutritional labs should be checked and, if low, parenteral or enteral nutrition via a distal feeding tube should be initiated and the malnutrition corrected before performing the procedure.

Equipment

If the gastrojejunostomy is to be performed laparoscopically, then the following equipment is required:

• Nasogastric or orogastric tube
• Liver retractor
• A laparoscope with a light source and monitor
• Insufflation equipment
• Laparoscopic trocars
• Bowel graspers
• Harmonic scalpel or Ligasure
• Electrocautery equipment
• Laparoscopic suction irrigator
• Laparoscopic linear cutting stapler or end-to-end anastomotic stapler depending on the planned technique
• Esophagogastroduodenal scope

If the gastrojejunostomy is to be performed open, then the following equipment is required:

• Nasogastric or orogastric tube
• Liver retractor
• Bowel clamps
• Bowel forceps
• Harmonic scalpel or Ligasure
• Electrocautery equipment
• Suction irrigator
• Linear cutting stapler, end-to-end anastomotic stapler, or appropriate suture depending on the planned technique
• Needle driver
• Esophagogastroduodenal scope

Personnel

To perform a gastrojejunostomy, a fully staffed operation room is required, including a surgeon, assistant surgeon, scrub tech, anesthesiologist, and a circulating nurse.

Additional personnel to assist in both pre- and post-operative care depends on the indication for the procedure performed and may include:

• Gastroenterologist
• Oncologist
• Dietician
• Psychiatrist
• Pharmacist
• ICU or floor nurses
• Discharge planner

Preparation

The appropriate preparation before performing gastrojejunostomy varies depending on the indication for the procedure.

If the gastrojejunostomy is being performed after resection of malignancy, then preparation may include neoadjuvant chemotherapy, nutritional support, and planning follow-up care in conjunction with an oncology team.

If the gastrojejunostomy is being performed to bypass an obstruction such as that which might occur from an ulcer, then ensuring that the patient is not malnourished is the initial preparation. This could include consulting a nutritionist, as well as potentially starting parenteral nutrition or placing a distal feeding tube.

If the gastrojejunostomy is being performed as part of a weight-loss procedure, then the patient requires a full bariatric work-up including meeting with a dietician, establishing a preoperative weight loss plan, meeting with a psychologist or psychiatrist for evaluation, and optimizing other risk factors such as glucose and blood pressure control.

Technique or Treatment

As noted previously, there are many indications for gastrojejunostomy, which will alter how the procedure is performed. The technique for a gastrojejunostomy as part of a Roux-en-Y bypass has been described in a previous StatPearls article.[13] Thus the technique noted here will focus on the creation of gastrojejunostomy in the setting of distal gastric obstruction.

Step 1: Obtain Access to the Abdominal Cavity

The patient should be placed in a supine position with the arms abducted at right angles and a nasogastric or orogastric tube placed to decompress the stomach. The abdominal cavity can be accessed by making an incision from the xiphoid to the umbilicus and may be extended if greater exposure is needed. If a laparoscopic technique is being used, then the abdominal cavity may be accessed using a Hasson, Veress, or Visiport technique, after which the other needed trocars.Once access is obtained, the liver should be retracted laterally in both the open or laparoscopic techniques.

Step 2: Determine the Site of the Gastrostomy

The site of the gastrostomy should be selected 3-5 cm from either the obstructing mass, be it an ulcer or malignancy, or from the pylorus. The area chosen should be low on the greater curvature, as selecting the site too high can lead to intractable biliary reflux and reduced gastric emptying.

Step 3: Approximating the Jejunal Loop

Next, a loop of jejunum 10-15 cm from the ligament of Trietz should be selected and approximated near the gastrostomy chosen site using the bowel clamps in an antecolic fashion, although retrocolic techniques exist. If a retrocolic technique is chosen, it is vital to close the transverse mesocolon defect, also known as Petersen space. Care should be taken that the loop is not under tension when near the stomach and is in an isoperistaltic conformation. Once an appropriate loop is in place, a permanent suture is used to fix the jejunum to the stomach using seromuscular bites.

Step 4: Creation of the Jejunostomy and Gastrostomy

Openings in the stomach and jejunum are created approximately 1 cm from the seromuscular stitches and about 5 cm in length. The suction irrigator should be at the ready for this stage to remove any leaked gastric or intestinal contents.

Step 5: Creation of the Anastomosis

Full-thickness posterior stitches using absorbable suture with the first knot placed outside the lumen of the stomach and the jejunum. The posterior and anterior segments of the anastomosis are sutured using Connel stitches, which is a running horizontal mattress stitch. The anterior outer layer is then oversewn using Lembert stitches in the seromuscular layer.

Step 6: Hemostasis and Leak Test

The anastomosis should be carefully inspected for any bleeding, and areas of significant bleeding may be oversewn. The anastomosis should then be placed underwater using the suction irrigator, and the esophagogastroduodenal scope advanced into the stomach. The stomach can then be inflated, and the anastomosis investigated for any leaks.

Stapled Technique

Stapled techniques are similar except the stapler is used to approximate the jejunum, and the stomach rather than suture and the gastrostomy and jejunostomy only need to be large enough to allow the stapler in. The gastrostomy and jejunostomy sites can then be closed with suture or an additional staple load.

Postoperative Care

Patients are typically admitted after the creation of a gastrojejunostomy, especially if it is combined with a gastric resection. Patients are usually started on a low volume diet of clear liquids and gradually advanced as tolerated. It often takes patients a few days to tolerate enough oral intake to prevent becoming dehydrated.[14] The patient should be maintained on supplemental intravenous fluids until they can tolerate sufficient oral intake.

Complications

Since gastrojejunostomy is a complicated surgical procedure, it comes with a significant amount of possible complications including, but not limited to:

Postoperative Nausea and Emesis

This typically resolves spontaneously with supportive treatment, although persistent nausea and emesis may indicate a technical error and possible bowel obstruction.

Hemorrhage

Always a possible complication for any operation. This may range from a small bleed, which resolves spontaneously to a significant bleed requiring operative revision.

Deep Vein Thrombosis and Possible Embolus

Always a possible complication for any operation. Patients should be kept on an anticoagulation regimen until they are ambulating.

Anastomotic Leak

Anastomotic leak is a feared complication of gastrojejunostomy, which most commonly presents on the third to fifth postoperative day. The first sign is typically tachycardia, followed by abdominal pain, and any patient with these symptoms should be evaluated for a possible anastomotic leak.[15]

Bowel Obstruction

The bowel may be obstructed early secondary to a technical error such as excessive kinking of the bowel or late secondary to adhesions or other issues. While a trial of supportive care is not unreasonable, the prolonged obstruction will require operative revision.

Internal Herniation

After altering the native anatomy to create a gastrojejunostomy, there exists the possibility of a loop of bowel herniating through a non-native space, such as Petersen space. An internal hernia is always a surgical emergency as it creates a closed-loop obstruction and can strangulate the bowel.[16]

Nutritional or Micro Nutritional Deficiency

By definition, a gastrojejunostomy bypasses at least some of the absorptive surface of the small bowel. If a significant enough amount of intestine is bypassed, the patient may lack the ability to absorb sufficient nutrients and become malnourished. Additionally, depending on the portion of bowel bypassed, certain micronutrients may not be sufficiently absorbed, causing a specific micronutrient deficiency.[17]

Dumping Syndrome

In anastomosing the stomach directly to the jejunum, high osmotic chyme is dumped directly from the stomach. There are early and late types of dumping syndrome, both of which can be prevented by eating multiple small meals rather than a few larger ones.[7]

Marginal Ulcer

By directly connecting the acidic stomach to the jejunum, which lacks the protective mechanisms of the duodenum, a gastrojejunostomy predisposes the region of the jejunum closest to the stomach to developing an ulcer.[18]

Bile Reflux

In connecting the stomach to the jejunum bile from the duodenum proceeds in an antegrade fashion and can enter the stomach from the anastomotic site. This bile can then irritate the stomach in a condition termed bile reflux.

Clinical Significance

Gastrojejunostomy plays a role in treating several ailments ranging from gastric outlet obstruction to morbid obesity. Healthcare providers of all levels should be aware of this procedure and its potential complications to ensure optimal outcomes. Patients who have undergone any procedure that includes a gastrojejunostomy are at risk for numerous complications, as mentioned previously, and any healthcare provider caring for this patient population must understand how the altered anatomy may cause specific issues to present.

Enhancing Healthcare Team Outcomes

Any procedure that includes a gastrojejunostomy permanently alters the patient's anatomy; therefore, the care of this patient population includes not just the perioperative period but the patient's entire life. While signs and symptoms concerning a bowel obstruction can be treated in a typical patient with nasogastric decompression and bowel rest, it may represent an internal hernia and, therefore, a life-threatening condition in a patient with a gastrojejunostomy. Every individual involved in the care for a patient with a gastrojejunostomy must be aware of the procedure performed so that they may be vigilant for signs or symptoms that are typically benign in the average patient but highly concerning in gastrojejunostomy patients. Therefore clear and constant communication between the entire healthcare team throughout is particularly critical in this patient population to ensure that subtle but significant findings are not missed.

Nursing, Allied Health, and Interprofessional Team Interventions

As noted previously, the most critical component in caring for a patient with a gastrojejunostomy is clear and constant communication between all facets of the care team. In many instances, complications secondary to a surgery that includes a gastrojejunostomy is promptly proceeding to the operating room and ensuring that is not delayed can be the most critical part of the patient's care. Typical interventions for issues with the small bowel, such as nasogastric decompression, are ineffective in the setting of an internal hernia and therefore, should not be relied upon in patients with gastrojejunostomies. Ultimately, the best intervention for a patient who has had this type of surgery is an early intervention, therefore focus should be on early diagnosis and prompt return to the operation room should any significant problem arise.

Nursing, Allied Health, and Interprofessional Team Monitoring

Healthcare providers at any level caring for a patient with a gastrojejunostomy should recall that the patient's anatomy is significantly different from the average patient, and they require much more attention. Subtle findings such as difficulty passing stool and flatus or nausea and emesis may indicate an internal hernia and thus, a closed-loop obstruction requiring immediate operative intervention. Unfortunately, the complications secondary to a gastrojejunostomy may not declare themselves on plain abdominal films or even CT scans, which may lead to significant delays in diagnosis. It is thus imperative that even relatively minor changes in the patient's status such as tachycardia or persistent but moderate abdominal pain immediately to be reported to the entire healthcare team to ensure complications are not missed.