Meckel's diverticulum

1. Meckel’s Diverticulum
Leor Arbel, MS-3

2. Background
• Most prevalent congenital anomaly of the GI tract
• True diverticula - contains all layers found in normal small intestine
• Usually located in the ileum, within 100 cm of the ileocecal valve
• ~60% contain heterotopic mucosa (gastric mucosa > pancreatic acini >
Brunner’s glands, pancreatic islets, colonic mucosa, etc)
• Neoplasms, MC carcinoid tumors, are found in ~0.5-3% of symptomatic
Meckel’s diverticula
• “Rule of 2’s” – useful (but crude) mnemonic
• 2% prevalence
• 2:1 male dominance
• 2 ft proximal to Ileocecal valve (in adults)
• Half of symptomatic pts are < 2 y/o

3. Pathophysiology
• In 8th wk of gestation, omphalomesenteric duct (aka vitelline duct) normally
obliterates, just before midgut returns to abdomen
• Failure or incomplete vitelline duct obliteration results in a spectrum of
abnormalities, including omphalomesenteric fistulas and enterocysts (image on
next slide)
• However, the MC abnormality associated with this is Meckel’s diverticulum
• Remnant of the Left Vitelline Artery may persist, too, forming a
mesodiverticular band tethering the Meckel’s diverticulum to the mesentery of
the ileum (image on next slide)

4. Pathophysiology cont’d
Left: Embryology
diagram of vitelline
duct incorporation
into umbilical cord
Right: Abnormalities
associated with failure
of vitelline duct
obliteration
Source:
GI Embryology Flash Cards

5. Pathophysiology cont’d
A. Meckel’s diverticulum
w/mesodiverticular band
B. Entrapment of intestine
by mesodiverticular band
Figure from Schwartz’s
Principles of Surgery, 10e

6. Pathophysiology cont’d
• May cause bleeding (classically painless rectal bleeding) - usually the result of ileal
mucosal ulceration that occurs adjacent to the acid-producing heterotopic gastric
mucosa within the diverticulum
• May cause intestinal obstruction – a/w the following mechanisms:
• Volvulus around fibrous band attaching diverticulum to umbilicus
• Entrapment by a mesodiverticular band
• Intussusception with the Meckel’s diverticulum serving as the lead point
• Stricture formation due to chronic diverticulitis
• May also be contained within inguinal or femoral hernia sacs -- this is known as
Littre’s Hernia
• If it becomes incarcerated, it can also cause intestinal obstruction

7. Clinical Manifestations
• Asymptomatic unless associated complications arise
• Lifetime incidence of complications in pts with Meckel’s diverticula has been
estimated to be btwn 4-6%
• It was previously thought that the risk of developing a complication decreases
with age – however, more recent data suggests that this is untrue and that the
risk of developing Meckel’s related complications does NOT change with
age! (Cullen et al)
• MC presentations a/w symptomatic Meckel’s diverticula are:
• Bleeding  MC presentation in pts < 18 y/o (> 50% of cases)
• Intestinal Obstruction  MC presentation in adults
• Diverticulitis  Presents w/a clinical picture that mimics acute appendicitis

8. Summary Slide: Complications a/w Meckel’s Diverticula
Source:
Castleden (1970)

9. Diagnosis
• Most are found incidentally (eg radiographic imaging, endoscopy, or during surgery)
• For pts presenting with symptoms suggestive of Meckel’s diverticulum,
confirmatory imaging may be sought (but there are some challenges to keep in mind)
• CT scans – sensitivity too low
• Enteroclysis – 75% accuracy but usu N/A during acute presentations
• Technetium-99m-pertechnetate scan (aka Meckel scan) – can be very helpful but this
test is only (+) when ectopic gastric mucosa (which can take up the tracer) is present.
Also, while the accuracy of this scan is 90% in pediatric pts, it is < 50% in adults
(images on next slide)
• Angiography – can localize site of bleed in pts presenting w/acute hemorrhage

10. Meckel’s Diverticulum Dx: 99mTc-Pertechnetate Scintigraphy
Meckel’s Diverticulum with ectopic gastric
tissue. Image shows an abnormal focus of
radiotracer uptake in the RLQ (arrow).
Figure from Schwartz’s Principles of
Surgery, 10e

11. Tx of Symptomatic Meckel’s Diverticula
• Surgical resection: Diverticulectomy + removal of associated
bands connecting diverticulum to abdominal wall or intestinal
mesentery
• Additional surgical considerations:
• If bleeding was the pt’s presentation, segmental resection of ileum that
includes both the diverticulum and the adjacent ileal ulcer should be
performed
• Segmental ileal resection may also be needed if there is a tumor
present, or if the base of the diverticulum is inflamed or perforated

12. Figure from Schwartz’s
Principles of Surgery, 10e

13. Tx of Asymptomatic Meckel’s Diverticula
• Unfortunately, mgmt. of asymptomatic (incidentally found) Meckel’s
diverticula is less straightforward – more controversy!
• Until recently, recommendation was against PPx removal, given the
relatively low lifetime incidence of complications
• However, more recently, there has been greater endorsement of PPx
diverticulectomy. Proponents argue that there is minimal morbidity a/w
Meckel’s diverticulectomy and that the lifetime incidence of complications
reported in the literature may be erroneously low.
• Still, others have advocated in favor of a more selective approach that
recommends removal only in cases where the diverticula is attached by
bands and or has a narrow base
• Minimal controlled data supporting/refuting any of these recommendations

14. References
• Tavakkoli A, Ashley SW, Zinner MJ. Small Intestine. In: Brunicardi F, Andersen
DK, Billiar TR, Dunn DL, Hunter JG, Matthews JB, Pollock RE. eds. Schwartz's
Principles of Surgery, 10e New York, NY: McGraw-Hill;
2015. http://accessmedicine.mhmedical.com.ezproxy.med.ucf.edu/content.aspx?book
id=980&sectionid=59610870. Accessed March 03, 2017.
• Cullen JJ, Kelly KA, Moir CR, et al. Surgical management of Meckel's diverticulum.
An epidemiologic, population-based study. Ann Surg 1994;220:564-9.
• Castleden, W.M. (1970) Meckel's diverticulum in umblical hernia. Br. J. Surg.,
57:932.