You are in: eMedicine Specialties > Pediatrics: Surgery > General Surgery Alimentary Tract DuplicationsArticle Last Updated: Jan 24, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 12
  Author: Marc Michalsky, MD, Assistant Professor of Clinical Surgery, Department of Pediatric Surgery, Columbus Children's Hospital, Ohio State University Marc Michalsky is a member of the following medical societies: American College of Surgeons and American Medical Association Coauthor(s): Gail E Besner, MD, Professor of Surgery and Pediatrics, Department of Surgery, Ohio State University College of Medicine and Public Health; Director, Pediatric Surgical Research, Department of Surgery, Children's Hospital Editors: Mary L Hilfiker, MD, PhD, Chief, Division of Pediatric Surgery, Assistant Professor, Department of Surgery, University of California at San Diego Medical Center; Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine.com, Inc; Michael G Caty, MD, Associate Professor of Surgery and Pediatrics; Surgeon-in-Chief, Department of Pediatric Surgery, State University of New York at Buffalo; Consulting Staff, Children's Hospital of Buffalo; H Biemann Othersen Jr, MD, Professor of Surgery and Pediatrics, Emeritus Head, Division of Pediatric Surgery, Medical University of South Carolina; Marleta Reynolds, MD, Professor of Surgery, Feinberg School of Medicine, Northwestern University; Interim Head, Division of Pediatric Surgery, Department of Surgery, Children's Memorial Hospital of Chicago Author and Editor Disclosure Synonyms and related keywords: alimentary tract duplications, duplication cysts, enteric cysts, intestinal diverticulum, intestinal diverticula, enterocystomas, enterogenous cysts, supernumerary accessory organs, ileum duplex, giant diverticulum, giant diverticula, unusual Meckel diverticulum, unusual Meckel diverticula, alimentary tract malformation, intestinal duplication, esophageal duplication, thoracoabdominal duplication, gastric duplication, duodenal duplication, jejunal duplication, ileal duplication, tubular duplication, colonic duplication, rectal duplication, hindgut duplication, spina bifida, hemivertebrae, myelomeningocele, diaphragmatic herniation, esophageal atresia, hypertrophic pyloric stenosis, volvulus, intussusception, imperforate anus INTRODUCTIONSection 2 of 12
  Congenital alimentary tract malformations are rare developmental errors that have been assigned several different names, including enterocystomas, enterogenous cysts, supernumerary accessory organs, ileum duplex, giant diverticula, and unusual Meckel diverticulum. The term intestinal duplication was first used by Fitz1 but was not widely used until it was popularized by Ladd in the 1930s,2 with further classifications by Gross in the 1950s.3 This article reviews the incidence, embryology, anatomy, common clinical presentations and principals of diagnosis, and surgical interventions of the spectrum of alimentary tract duplications. History of the ProcedureFitz first used the term intestinal duplication in 1844 when he published a paper in which he suggested that alimentary tract duplications arose from persistent omphalomesenteric remnants.1 Because of the relative scarcity of such anomalies, current literature mainly consists of small populations and case reports rather than any large single or multi-institutional series. ProblemIntestinal duplications are intimately attached to an adjacent segment of normal intestine (ie, share a common wall). Such anomalies possess at least one exterior coat of smooth muscle and are lined with various types of GI mucosa. FrequencyApproximately two thirds of all intestinal duplications are discovered within the first 2 years of life, with one third identified in the newborn period. Although the exact incidence is unknown, Potter reported 2 cases in 1961 in more than 9000 fetal and neonatal autopsies.4 EtiologyBecause duplication of the alimentary tract takes many different forms, the application of a single embryologic theory is not likely to be considered valid. This has led to the proposal of several different theories in an attempt to explain the embryologic events that culminate in intestinal duplication. PathophysiologyThe split notochord theory proposes a neural tube traction mechanism as an explanation for the 15% of enteric duplications with associated vertebral defects. Specifically, an embryologic error may result in abnormal diverticularization of the GI endoderm through the developing notochord at 4 weeks' gestation. A second theory suggests that a failure in the regression of embryonic diverticula occurs, resulting in the formation of enteric cysts. A third proposal offers the suggestion that external compression of adjacent loops of bowel may result in side-by-side duplication caused by adherence of 2 loops. Finally, errors in epithelial recanalization (believed to occur at 5-8 weeks' gestation) have been proposed as a possible explanation for the existence of small submucosal duplications. ClinicalAlthough many duplications are incidentally diagnosed, most patients present with a combination of pain and obstructive symptoms. These symptoms may be the direct effects of distention of the duplication or may be caused by compression of adjacent organs (including their associated blood supplies). In addition, abrupt hemorrhage with hemodynamic instability can be encountered in the case of a cyst lined with gastric mucosa5 that ulcerates and eventually erodes into adjacent organs and/or vessels. INDICATIONSSection 3 of 12
Indications for surgical intervention with regard to duplications of the alimentary tract often arise in an acute setting. Specifically, patients with previously undetected duplications may present in the setting of bowel obstruction or severe GI hemorrhage (ie, ulcerating gastric mucosa within a duplication cyst). If incidentally encountered, duplications should be surgically addressed to avoid future complications. RELEVANT ANATOMYSection 4 of 12
A review of literature regarding alimentary tract duplications in more than 500 patients reveals a widely varied anatomic distribution (see Media file 1). Approximately 75% of duplications have been reported to be located within the abdominal cavity, whereas the remaining are intrathoracic (20%) or thoracoabdominal (5%). Jejunal and ileal lesions are the most commonly encountered (53%), followed by mediastinal (18%), colonic (13%), gastric (7%), duodenal (6%), rectal (4%), thoracoabdominal (2%), and cervical (1%) lesions. Seventy-five percent of duplications are considered cystic, with no communication to adjacent intestine, whereas the remaining duplications are true cylindrical structures that may or may not have one or more direct communications across the common septum. All intestinal duplications contain at least one layer of smooth muscle and some type of intestinal mucosal layer within the lumen. They are often intimately attached to an adjacent segment of the normal GI tract; sacrificing a segment of normal intestinal tract is sometimes necessary during the resection of a duplication cyst. The mucosal lining within alimentary tract duplications does not necessarily correspond with the adjacent normal intestine and may display components of several different types of GI tract mucosa. Noncommunicating duplications typically contain clear alkaline fluid, except in cases in which gastric mucosa is present (25%) and acidic fluid is observed. In addition, nonactivated pancreatic enzymes may also be observed in cases of ectopic pancreatic tissue within the duplication lesion. Cervical and thoracic duplications Esophageal duplications are relatively uncommon, and patients tend to present at a later age compared with those who have duplications in other areas of the alimentary tract. Although duplications of the esophagus are reported throughout its length, most are located in its distal half. These lesions are cystic and located in the posterior mediastinum (more commonly on the right side than the left side), with a high association of vertebral abnormalities (eg, spina bifida, hemivertebrae, myelomeningocele) compared with nonthoracic duplications. Additionally, posterolateral diaphragmatic herniation and esophageal atresia have been reported in association with esophageal duplications. Gastric mucosa has been reported to be present inapproximately30%ofesophagealduplications; it frequently gives rise to bleeding secondary to mucosal ulceration and erosion into adjacent structures. Thoracoabdominal duplications These duplications are also considered to be rare and are believed to represent long diverticula that originate in the intestine and extend into the thoracic cavity. Thoracoabdominal lesions are more often located on the right side of the posterior mediastinum than on the left (similar to thoracic duplications). Gastric duplications Duplications involving the stomach are the least common of the abdominal duplications (approximately 5%), they are more prevalent in males than in females, and patients present at a mean age of 3 years (one third are diagnosed during the neonatal period). Gastric duplications are typically noncommunicating cystic structures located along the greater curve or posterior aspect of the stomach but have been reported at the level of the pylorus and may be mistaken for hypertrophic pyloric stenosis. Duodenal duplications Duodenal duplications vary in size and are most often located posteromedially, sharing a common wall with the true duodenum and often partially embedded in the head of the pancreas. Obstruction is the most common clinical presentation; however, pancreatitis6, 7 and peptic ulceration of gastric mucosa within the duplication have also been reported. Jejunal and ileal duplications Duplications of the ileum represent the most common location of all alimentary tract duplications and typically appear as noncommunicating spherical cysts of varying sizes. Because of their common location at the mesenteric border, they may be easily mistaken for mesenteric or omental cysts, only to be clarified by identification of a mucosal rather than endothelial lining. Tubular duplications These may be extremely short or comprise a large amount of the length of the normal intestine. As opposed to spherical cysts, the tubular variety may communicate with the normal intestine at one or several points along the common wall. Duplications of the colon and rectum Cystic and tubular duplications of the colon are rare entities. Cystic duplications have been reported to cause obstruction of the large bowel as a result of direct compression, volvulus, and intussusception,8 whereas tubular duplications of the rectum have been described as having direct communication with the peroneum. Hindgut duplications Another entity that has been described is hindgut duplication, wherein the distal ileum, cecum, appendix, and entire colon are duplicated and drain through one or several perineal openings. This malformation may be accompanied by imperforate anus, involving both the normal anus and the pathologic opening; it has been associated with bladder abnormalities, duplication of external genitalia, and extrapulmonary sequestration9 with esophageal communication. Colonic and/or rectal duplications may distend secondary to inadequate distal drainage, resulting in obstruction and even perforation. CONTRAINDICATIONSSection 5 of 12
No specific contraindications to the surgical management of alimentary tract duplication are recognized. WORKUPSection 6 of 12
Lab Studies
Imaging Studies
Histologic FindingsHistologic analysis of alimentary tract duplications typically reveals at least one outer muscular layer with an inner GI mucosal lining. The mucosal lining does not necessarily correspond to that of the adjacent normal intestine and may be composed of several different types of GI mucosa. TREATMENTSection 7 of 12
Surgical therapySurgical treatment of alimentary tract duplications is largely dictated by the specific anatomic location of the lesion and its relation to normal anatomic structures. Attention to vital structures (eg, bile duct, named vessels) must be considered when attempting to resect an intestinal duplication cyst. Preoperative detailsAlthough the diagnosis of alimentary tract duplication is often not made until the patient is in the operating room, preoperative preparation is based on standard surgical principles of adequate hemodynamic status and the use of appropriate preoperative medications as deemed necessary (eg, antibiotics). The use of bowel prep should be considered as part of the preoperative routine. Intraoperative detailsIn most instances, cystic duplications can be completely excised. Resection of normal intestine must often accompany removal of the lesion because of the intimate attachment of the common wall or because isolated resection of the cyst would compromise blood flow to the adjacent intestinal segment (see Media file 4). An alternative approach involves marsupialization of the cystic structure. This consists of a partial cystectomy combined with mucosal stripping of the remaining cyst wall to preserve normal anatomy. Resection of tubular duplications follows the same principles as cystic duplications but may pose a more complicated venture, especially when the patient has a long tubular segment or total intestinal duplication involving the upper GI tract and small bowel (incidence of gastric mucosa is high). Again, marsupialization combined with mucosal stripping becomes an important tool in the surgical treatment of these entities. Tubular duplication of the hindgut may be left in situ if adequate drainage (by surgically joining the 2 lumens) or mucosal stripping of the defunctionalized portion can be achieved. Postoperative detailsPostoperative care is considered to be routine and is directed at the specific surgical intervention undertaken. Follow-upBecause of the significant incidence of synchronous lesions, follow-up imaging (eg, CT scanning, ultrasonography) of additional body cavities should be performed in the event that the diagnosis of alimentary tract duplication was made intraoperatively. COMPLICATIONSSection 8 of 12
Complications related to the discovery of an intestinal duplication cyst include bowel obstruction and hemorrhage. Because most intestinal duplications are cystic and appear in the ileum, requiring a limited resection, complications related to surgical intervention are typically nonspecific and include postoperative bleeding, infection, and bowel obstruction. However, in patients with large tubular duplications, injury to the normal intestine with resultant short bowel syndrome must be considered. Other complications include scattered reports of intestinal carcinomas found within duplication cysts. OUTCOME AND PROGNOSISSection 9 of 12
Although current literature does not specifically address the prognosis and outcome related to the diagnosis of alimentary tract duplications, the overall outcome is generally accepted as favorable. FUTURE AND CONTROVERSIESSection 10 of 12
As with many types of surgical interventions, several reports have been published promoting the use of minimally invasive instrumentation (ie, laparoscopy) for the definitive diagnosis and treatment of alimentary tract duplications.10, 11 MULTIMEDIASection 11 of 12
REFERENCESSection 12 of 12
Alimentary Tract Duplications excerpt Article Last Updated: Jan 24, 2008 | |||||||||||||||||||||||||||||||||
