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Pediatrics: Surgery > General Surgery
Meckel Diverticulum: Surgical Perspective
Article Last Updated: May 17, 2007
AUTHOR AND EDITOR INFORMATION
Section 1 of 12  
Author: Mark V Mazziotti, MD, Assistant Professor of Pediatric Surgery, Department of Surgery, Baylor College of Medicine, Texas Children's Hospital
Mark V Mazziotti is a member of the following medical societies: Alpha Omega Alpha, American College of Surgeons, American Medical Association, American Pediatric Surgical Association, and Phi Beta Kappa
Editors: Robert K Minkes, MD, PhD, Staff Pediatric Surgeon, Houston Pediatric Surgeons, Texas Children's Hospital; Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine.com, Inc; Nicholas A Shorter, MD, Professor of Clinical Surgery and Clinical Pediatrics, State University of New York-Downstate University; Division Chief, Department of Surgery, Division of Pediatric Surgery, State University of New York-Downstate Medical Center; H Biemann Othersen Jr, MD, Professor of Surgery and Pediatrics, Emeritus Head, Division of Pediatric Surgery, Medical University of South Carolina; Harsh Grewal, MD, FACS, FAAP, Professor of Surgery and Pediatrics, Temple University School of Medicine; Chief, Section of Pediatric Surgery, Temple University Children's Medical Center
Author and Editor Disclosure
Synonyms and related keywords:
omphalomesenteric duct, omphalomesenteric duct remnant, vitelline duct, vitelline duct remnant, yolk stalk, yolk stalk remnant, pedunculus vitellinus, laparoscopic Meckel diverticulectomy, Meckel diverticulum, Meckel diverticulitis, bowel obstruction, Meckel fibrous band, Littre hernia, mesodiverticular band, umbilical drainage, patent omphalomesenteric duct, urachal remnant, Meckel diverticulectomy, ectopic mucosa, Meckel scan, intussuscepted Meckel diverticulum
A Meckel diverticulum is an embryologic abnormality that is part of a spectrum of anomalies known as yolk stalk or omphalomesenteric duct remnants. Depending on the type of anomaly, patients may be completely asymptomatic or may present with bleeding, inflammation, obstruction, or umbilical drainage.
History of the Procedure
Fabricus Hildanus first described a Meckel diverticulum in 1598. In 1809, Johann Meckel, an anatomist, described this anomaly in detail. He identified the origin of the diverticulum as the omphalomesenteric duct and emphasized that this anatomic abnormality was a potential cause of disease. In 1904, Salzer became the first to identify ectopic mucosa within the diverticulum.
Frequency
Meckel diverticula are found in approximately 2% of the population. The prevalence of symptomatic Meckel diverticula is estimated to be 4-35% of the at-risk population, depending on the age group studied. More than 60% of patients who develop symptoms from this anomaly are aged 2 years or younger.
Etiology
The existence of a Meckel diverticulum or one of its variants is due to simple embryology. The yolk sac of the developing embryo is connected to the primitive gut by the yolk stalk or vitelline (ie, omphalomesenteric) duct. This structure typically regresses between the fifth and seventh weeks of fetal life. If this process of regression fails, various anomalies can occur. This spectrum of defects includes a Meckel diverticulum, a fibrous cord attaching the distal ileum to the abdominal wall, an umbilical-intestinal fistula, a mucosa-lined cyst, or an umbilical sinus.
Pathophysiology
The pathophysiology varies depending on the etiology of symptoms (see Clinical).
Clinical
Meckel diverticula and omphalomesenteric variants may result in various clinical presentations, including painless bleeding, bowel obstruction, Meckel diverticulitis, and umbilical drainage. - Painless bleeding: Lower gastrointestinal hemorrhage is the most common symptom in patients with a symptomatic Meckel diverticulum. The mean age is 2 years, although this problem may occur in older children and even adults. The bleeding is typically painless; it can be massive and may require blood transfusion. Other causes of bleeding that may occur in this same age group include anal fissure, juvenile retention polyps, hemangiomas, peptic ulcer disease, inflammatory bowel disease, and primary hematologic disorders. Bleeding is secondary to ulcerated ileal mucosa resulting from ectopic gastric mucosa that is contained within the Meckel diverticulum. The gastric mucosa secretes acid, which results in ulceration of the adjacent normal ileal mucosa.
- Bowel obstruction: In children, obstruction is the second most common symptom in patients with symptomatic Meckel diverticula and occurs in approximately 25% of symptomatic patients. Obstruction can be caused by several mechanisms. Volvulus of the small intestine may occur around a Meckel fibrous band attached to the umbilicus. Intussusception of the Meckel diverticulum may also result in intestinal obstruction. Incarceration of the diverticulum in a hernia, known as a Littre hernia, is a third cause of obstruction. Another cause of bowel obstruction is entrapment of small bowel beneath the blood supply of the diverticulum, also known as a mesodiverticular band.
- Meckel diverticulitis: Diverticulitis may occur in as many as 20% of patients with complications from a Meckel diverticulum. Meckel diverticulitis is commonly misdiagnosed as acute appendicitis. Inflammation of the diverticulum may be due to obstruction of the lumen, which is analogous to the pathophysiology of acute appendicitis. Progression of such inflammation may lead to perforation and peritonitis. The possibility of Meckel diverticulitis underscores the need to explore the distal small bowel in patients with suspected appendicitis when a normal appendix is found.
- Umbilical drainage: Drainage of succus entericus or feculent discharge is due to a patent omphalomesenteric duct, whereas clear drainage should prompt a search for a urachal remnant.
- Umbilical mass or infection: Omphalomesenteric duct remnants may persist as an actual cystic structure, typically just beneath the umbilicus. This structure may be palpable upon physical examination or, if infected or ruptured, may lead to inflammatory changes in the umbilicus.
- Perforation: Because a Meckel diverticulum may contain ectopic gastric mucosa, the bordering small intestine mucosa may ulcerate, which may cause actual perforation of the intestine. This leads to peritonitis and free intraperitoneal air, which can be seen on plain abdominal films.
Indications for operation depend on the patient's presentation, as follows:
- Painless bleeding: As mentioned above, initial bleeding from a Meckel diverticulum can be massive. Therefore, the patient must be adequately resuscitated, which may require the transfusion of packed RBCs to return the hematocrit level to approximately 30%. Two large-bore intravenous lines must be in place in case bleeding recurs, and crossmatched blood should be available. If Meckel diverticulum bleeding is suspected, technetium-99m pertechnetate radioisotope scanning is the test of choice. This isotope is readily taken up by the ectopic gastric mucosa within the Meckel diverticulum. Once a positive result is obtained, the patient can be taken to the operating room for a Meckel diverticulectomy. False-negative results occur less than 2% of the time. The accuracy of such scanning may be increased with the use of pentagastrin, histamine-blockers, and glucagon.
- Bowel obstruction: Patients present with bowel obstruction due to volvulus, intussusception, a mesodiverticular band, or incarceration of the Meckel diverticulum in a hernia (although the presence of a Meckel diverticulum in a hernia does not actually increase the risk of incarceration). Despite these different causes, the clinical presentation is bowel obstruction. Patients present with obstipation, crampy abdominal pain, and vomiting, which may be bilious. Plain abdominal radiographs reveal dilated loops of small bowel with air-fluid levels and a paucity of gas distally. This classic presentation of bowel obstruction is all that is necessary to warrant transporting the patient to the operating room for an urgent laparotomy.
- Meckel diverticulitis: The presentation of Meckel diverticulitis may be indistinguishable from that of appendicitis. As with appendicitis, the course is progressive and may result in perforation, diffuse peritoneal contamination, and septic shock. Exploration is usually performed for suspected appendicitis, an inflamed Meckel diverticulum must be sought if a normal-appearing appendix is discovered.
- Umbilical drainage: Drainage of succus entericus or feculent material indicates a persistent connection between the intestine and the umbilicus. Ultrasonography or contrast studies may be used to confirm the diagnosis. An exploration can then be performed to resect the fistula.
The omphalomesenteric or vitelline duct typically arises from a point approximately 2 feet proximal to the ileocecal valve in adults. The Meckel diverticulum is an antimesenteric structure but receives its blood supply from the mesentery of the ileum. Thus, a typical feeding vessel (vitelline artery, also described as the omphalomesenteric mesentery) may be identified. It crosses from the mesentery of the ileum, across the intestine itself, and along the length of the diverticulum. This feeding vessel must be individually clipped and divided during a laparoscopic Meckel diverticulectomy. Meckel diverticula may contain ectopic mucosa. The 2 most common types of ectopic mucosa are gastric and pancreatic. As many as 50% of all diverticula contain gastric mucosa, whereas 5% contain pancreatic mucosa. Ectopic gastric mucosa results in secretion of acid onto adjacent ileal mucosa, causing ulceration and bleeding.
Because many of the operations for omphalomesenteric remnants are used in emergency situations, surgery has relatively few contraindications. However, patients must be adequately prepared for surgery, even given short notice. In patients who are bleeding, the blood volume must be returned to acceptable levels, and adequate intravenous access must be obtained. In patients with bowel obstruction and repeated emesis, electrolyte abnormalities must be corrected while hydration is restored.
Lab Studies
- CBC count: In patients with a bleeding Meckel diverticulum, assessment of the hemoglobin level is critical. This helps guide transfusion therapy and should be repeated following transfusion to ensure that the hemoglobin level has adequately risen. This test is also important in the assessment of the patient with Meckel diverticulitis. An increased WBC count and a left shift can support the diagnosis.
- Electrolyte levels: In patients with vomiting due to bowel obstruction, electrolyte abnormalities are common. Obtain serum levels of sodium, potassium, chloride, carbon dioxide, BUN, and creatinine. Studies are repeated as abnormalities are corrected.
Imaging Studies
- Technetium 99-m pertechnetate radioisotope scanning: Also known as the Meckel scan, this study is important in the evaluation of Meckel diverticula that contain ectopic gastric mucosa. The isotope is readily taken up by this mucosa. A Foley catheter can be placed to drain the bladder and to reduce signal intensity from this area. Because the false-negative result rate may approach 2%, pentagastrin (to stimulate the uptake of the radioisotope), histamine-blockers (to inhibit the secretion of the pertechnetate once it is taken up), and glucagon (to inhibit peristalsis and thereby decrease "wash-out" of the pertechnetate) may be used to increase the sensitivity of the test.
- Plain abdominal radiography: In patients with a Meckel diverticulum that causes bowel obstruction, plain radiography is needed and may reveal dilated bowel loops with air-fluid levels and a paucity of distal gas. In a protracted clinical course, perforation may occur, and free air may be seen on upright radiographs.
- Ultrasonography: Many centers use ultrasonography in the evaluation of abdominal pain. If the patient has Meckel diverticulitis, a thickened noncompressible tubular structure may be seen. These are many of the same criteria that are used to confirm the diagnosis of appendicitis using ultrasonography. Ultrasonography is also helpful in assessing patients with persistent umbilical drainage. Structures such as fistulous tracts and persistent cysts may be readily identified using ultrasonography.
- CT scanning: In many centers, abdominal-pelvic CT scanning is the radiologic test of choice if abdominal pain is present. In patients with Meckel diverticulitis, an inflammatory mass with peridiverticular stranding may be observed.
Diagnostic Procedures
- Diagnostic laparoscopy: Some patients have an unusual presentation and adjunctive assessment results that do not clearly lead to a particular diagnosis. In patients who have continued abdominal pain, laparoscopy may be useful. Laparoscopy has the advantage of being a minimally invasive approach to establish the diagnosis of intra-abdominal pathology. Laparoscopy can also be the primary form of treatment in various disorders.
Histologic Findings
A Meckel diverticulum is a true diverticulum, containing all 4 layers of the bowel wall. Ectopic mucosa is commonly found within a Meckel diverticulum. Gastric and pancreatic mucosa are the 2 most common types of ectopic mucosa. The remainder of the diverticulum lining is typical ileal mucosa.
Medical therapy
Medical treatment has no role in the management of a Meckel diverticulum.
Surgical therapy
The indications for surgical intervention in Meckel diverticulum vary based on the patient's presentation. In all cases, patients should be adequately resuscitated, and prophylactic antibiotics should be administered. - Painless bleeding
- Once a Meckel diverticulum has been diagnosed, laparotomy or laparoscopy can be used for resection. The goal is to resect the Meckel diverticulum, all ectopic gastric mucosa, and any ulcerated intestine to prevent recurrent bleeding.
- Many authors feel that laparoscopy is not adequate because it involves stapling the diverticulum at its junction with the ileum. Although most ectopic mucosa is at the tip of the diverticulum, this is not always the case. Furthermore, using laparoscopy may leave ulcerated ileum, which may bleed.
- To avoid these problems, the author uses a technique of laparoscopic-assisted bowel resection. A large umbilical port is placed, and the Meckel diverticulum is identified, grasped, and brought up to this umbilical incision. The port is then removed as the Meckel diverticulum and ileum are brought up through the umbilical incision (the incision is widened as needed).
- The author then resects of the Meckel diverticulum and ileum with primary anastomosis. A wedge resection of the diverticulum with inspection of the ileal mucosa to look for ulceration can also be performed. This wedge can then be closed, avoiding a circumferential suture line.
- Bowel obstruction
- Laparotomy is the procedure of choice for bowel obstruction. It typically involves a midline or transverse incision, which is cosmetically superior in children.
- If the volvulus is around a fibrous Meckel band, the bowel must be untwisted and observed after the band is divided. Frankly necrotic intestine must be resected.
- Another cause of bowel obstruction is an intussuscepted Meckel diverticulum. The Meckel diverticulum sags into the bowel lumen and then serves as a lead point and allows telescoping of the small intestine into first the distal ileum and then the large intestine. Attempts to reduce such a mass are sometimes difficult. Typically, the intussuscepted mass must be resected, and primary anastomosis must be performed.
- A third cause of bowel obstruction is an incarcerated hernia that contains a Meckel diverticulum, also called a Littre hernia. The hernia is reduced, and the Meckel diverticulum is resected.
- For a mesodiverticular band, the small bowel is reduced, and the diverticulum and its blood supply are resected.
- Meckel diverticulitis: The surgical approach is similar to the one used in acute appendicitis. Open or laparoscopic surgery can be used, and the diverticulum is divided at its base. The closure is performed perpendicular to the axis of the intestine to avoid any narrowing of the ileum. If perforation has occurred, the abdomen is copiously irrigated after resection of the diverticulum has been completed.
- Umbilical drainage: A periumbilical incision is made, and the abdomen is entered. The fistulous tract is identified and removed. After its connection with the ileum is divided, the enterotomy is closed with interrupted absorbable sutures in 1 or 2 layers (per the surgeon's preference).
Postoperative details
Postoperative care depends on the type of procedure performed. Patients with a relatively minor procedure such as diverticulectomy for diverticulitis or umbilical exploration for persistent fistula can resume a regular diet soon after surgery. Those with bowel obstruction or peritoneal contamination must wait until bowel function has returned to resume a regular diet.
Follow-up
A standard postoperative follow-up visit 7-10 days after surgery is recommended. If no problems are reported, no further testing or additional visits are required.
Complications are rare but may include bleeding and infection, wound dehiscence, or intra-abdominal abscess formation.
Patients do not have further bleeding episodes once the Meckel diverticulum and ectopic gastric mucosa have been excised. Patients who require exploratory laparotomy for bowel obstruction are at risk for adhesive bowel obstruction in the future.
The 2 controversies regarding Meckel diverticulum include the use of laparoscopy and the use of incidental diverticulectomy. Laparoscopy for diagnosis or excision of an inflamed diverticulum is not controversial. However, questions arise when laparoscopy is used in the setting of a bleeding Meckel diverticulum. Some have advocated routinely using laparoscopy in this situation. Opponents argue that, because the base of the diverticulum and the ileum cannot be palpated, ectopic mucosa could be left behind. Some surgeons routinely send the diverticulum for frozen section examination of the margin to determine that no ectopic mucosa remains. Others argue that ulcerated areas of the ileum remain, and, thus, the patient is still at risk for bleeding episodes in the immediate postoperative period. No randomized controlled studies have been performed to answer these questions. The other major controversy involves what to do with a Meckel diverticulum when it is discovered during an exploration for other reasons. The argument weighs the probability for future complications from a currently asymptomatic Meckel diverticulum against the potential morbidity of incidental Meckel diverticulectomy. If a thickening appears to be present upon palpation, the diverticulum may contain ectopic mucosa. These patients are at an increased risk of complications, and resection is warranted. Likewise, if the diverticulum has a narrow base, the likelihood of luminal obstruction and diverticulitis may be higher, and resection is appropriate. In most other cases, the diverticulum may be left in situ.
Media file 1:
Diagram depicting possible complications associated with different omphalomesenteric remnants. Meckel diverticula are symptomatic in 4-35% of patients. Infants and young children are more likely to present with symptoms.
- Figure A shows Meckel diverticulitis. These are true diverticula, which usually become inflamed due to obstruction.
- Figure B shows Meckel diverticula, which may contain ectopic gastric, pancreatic, or colonic mucosa. In the gastric ectopic mucosa, the acid secretion produced by the parietal cells erodes the adjacent intestinal mucosa, generating ulcers at the base of the diverticulum.
- Figure C shows the omphalomesenteric (vitelline) duct that connects the primitive gut to the yolk sac. It normally regresses between the fifth and seventh weeks of fetal life. When failed regression results in a fibrous band, the midgut may volvulate around it.
- Figure D shows fibrous bands, which also produce abnormal peritoneal spaces through which an internal hernia may result.
- Figure E shows an omphalointestinal fistula. If a patent connection persists between the intestine and the umbilicus, the entity is recognized as an omphalointestinal fistula.
- Figure F shows a persistent fibrous cord with a cyst. Failed regression of the vitelline duct may also lead to umbilical polyps, umbilical sinus, or umbilical cyst. Image courtesy of Jaime Shalkow, MD.
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| Media file 2:
The test of choice for a bleeding Meckel diverticulum is a technetium-99m pertechnetate isotope scan (Meckel scan). It concentrates the isotope in ectopic gastric mucosa, with a sensitivity of 85% and a specificity of 95%. In this scan, the isotope is seen in the stomach and the bladder (normal), with a radiotracer signal in the mid abdomen, suggesting the presence of a Meckel diverticulum with ectopic gastric mucosa. Image courtesy of Jaime Shalkow, MD. |
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| Media file 3:
Newborn infant with a persistent omphalomesenteric remnant. The remnant is being resected to prevent obstruction and to close the umbilical defect. Image courtesy of Kenneth Gow, MD, BSc, MSc, FRCSC, FACS, FAAP. |
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Laparoscopic image, courtesy of Charles L Snyder, MD. |
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| Media file 5:
Large Meckel diverticulum on the antimesenteric surface of the terminal ileum. Image courtesy of Richard A Falcone, Jr, MD. |
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The Meckel diverticulum has been opened after resection, revealing an ulcer and ectopic tissue, as indicated by the forceps. Image courtesy of Richard A Falcone, Jr, MD. |
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Resected Meckel diverticulum demonstrating an ulcer. |
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Meckel Diverticulum: Surgical Perspective excerpt Article Last Updated: May 17, 2007
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