Distinction Between Intraperitoneal and Extraperitoneal Processes

Figure 15-30 illustrates that in the ascending or descending colon, two of the haustral rows face intraper-itoneal structures. The TO-TL sacculations are in relation to the lateral paracolic gutter and the TM-TL row to the medial paracolic sulcus and the small bowel loops. Intraperitoneal processes in these areas, then, produce predominant changes on these haustra. In contrast, the posterior TM-TO row is unique in bearing relationship only to extraperitoneal processes, which are often clinically occult and radiologically confusing. Changes limited to this haustral row thus clearly indicate the site of the abnormality as extraperitoneal in nature.

Ascending Retrocecal Appendicitis

These observations have been most useful in the diagnosis of ascending retrocecal appendicitis.11 An ascending retrocecal position of the appendix is surprisingly common; its incidence ranges from 26% in surgical cases12 to 65% in an autopsy series13 (Fig. 15-31). In this position, the appendix may be intraperitoneal or extra-peritoneal (Fig. 15-32). It may be identified on plain films, contrast studies, and sectional imaging studies (Fig. 15-33).

Many complications of appendicitis are related to anatomic variations in the position of the appendix, re-

Fig. 15—30. Intraperitoneal and extraperitoneal relationships.

In the ascending and descending colon, the TO-TL and TM-TL rows bear intraperitoneal relationships and the TM-TO haustra face extraperitoneal structures. (Reproduced from Meyers et al.5)

Extraperitoneal

Extraperitoneal

Postional Variation The AppendixPleural Gutters
Fig. 15—31. Incidence of variations in position of the appendix, as determined by Wakely.13

fleeted clinically in the problem of differential diagnosis of acute appendiceal disease and lesions of the gallbladder, liver, right kidney, and base of the right lung or pleura. The radiologic features, however, constitute a characteristic pattern that permits precise localization and diagnosis. Inflammation associated with an intraperitoneal ascending retrocecal appendix occurs in the right paracolic gutter and involves the lateral (TO-TL) haustral row of the ascending colon (Fig. 15-34). In contrast, inflammation associated with an extraperito-neal ascending retrocecal appendix affects primarily the posterior (TM-TO) haustral row (Figs. 15-35 through 15-38). Computed tomography may readily demonstrate the extraperitoneal inflammatory collection and its effect upon the colon14,15 (Fig. 15-39) and perhaps associated consequences17 (Fig. 15-40). A subhepatic appendix and its inflammatory complications may be readily evident (Figs. 15-41 through 15-43). The appendix itself may show definite abnormalities, including mass displacement (Fig. 15-34), sinus tracts (Fig. 1537), and opacification of the abscess cavity. Fulminating infection may infiltrate the flank wall and subcutaneous tissues (Fig. 15-44).

If the appendix is not visible, I have observed that its location can still be confidently inferred by the position of the ileocecal valve, owing to the embryologic development of rotation and fixation.11 If the appendix is in-traperitoneal and points inferiorly toward the pelvis, the ileum enters the cecum from the medial aspect so that the customary position of the ileocecal valve is on the medial wall. However, with an ascending retrocecal appendix, the ileum enters from behind so that the ileo-cecal valve may be seen on the posterior wall.

Retrocecal

Fig. 15-32. Normal variations in the position and peritoneal fixation of the appendix.

(a) Intraperitoneal, pointing over the brim of the pelvis.

(b) Intraperitoneal, ascending retrocecal.

(c) Extraperitoneal, ascending retrocecal. A paracecal fossa is present.

(d) Extraperitoneal, ascending retrocecal.

(e) Extraperitoneal, ascending retrocecal, lying anterior to the right kidney (K) deep to the liver, associated with an undescended subhepatic cecum. The terminal ileum, also extraperitoneal, enters the cecum from behind. (Reproduced from Meyers and Oliphant.11)

Fig. 15-32. Normal variations in the position and peritoneal fixation of the appendix.

(a) Intraperitoneal, pointing over the brim of the pelvis.

(b) Intraperitoneal, ascending retrocecal.

(c) Extraperitoneal, ascending retrocecal. A paracecal fossa is present.

(d) Extraperitoneal, ascending retrocecal.

(e) Extraperitoneal, ascending retrocecal, lying anterior to the right kidney (K) deep to the liver, associated with an undescended subhepatic cecum. The terminal ileum, also extraperitoneal, enters the cecum from behind. (Reproduced from Meyers and Oliphant.11)

Abdominal Trauma

In cases of abdominal trauma with medial displacement of the ascending or descending colon, identification of the haustral row primarily affected may be the key in the differential diagnosis between intraperitoneal and extraperitoneal bleeding. Intraperitoneal fluid in the lateral paracolic gutter tends to compress the TO-TL row. In contrast, extraperitoneal blood in relationship to the colon flattens particularly the TM-TO haustral row (Fig. 15-45).

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Subhepatic Cecum Image

Fig. 15-33. Ascending retrocecal appendix with an appendicolith.

(a) Plain film. A gas-containing appendix (arrows) can be visualized through the feces-laden ascending colon.

(b) Tortuous portions of the retrocecal appendix (arrows) are shown on CT. Incidentally noted is the opacified ureter anterior to the psoas muscle.

(c) An appendicolith is evident within its cephalad tip (arrow).

Fig. 15-33. Ascending retrocecal appendix with an appendicolith.

(a) Plain film. A gas-containing appendix (arrows) can be visualized through the feces-laden ascending colon.

(b) Tortuous portions of the retrocecal appendix (arrows) are shown on CT. Incidentally noted is the opacified ureter anterior to the psoas muscle.

(c) An appendicolith is evident within its cephalad tip (arrow).

Appendicitis Picture Inside Colon

Fig. 15—34. Intraperitoneal ascending retrocecal appendicitis.

(a) Frontal view shows mass displacement and nodular deformity of the lateral contour of the proximal ascending colon.

(b) Oblique view reveals gentle arcuate mass displacement of an ascending retrocecal appendix (arrows). The posterior wall of the proximal ascending colon is grossly intact.

(Reproduced from Meyers and Oliphant.11)

Fig. 15—34. Intraperitoneal ascending retrocecal appendicitis.

(a) Frontal view shows mass displacement and nodular deformity of the lateral contour of the proximal ascending colon.

(b) Oblique view reveals gentle arcuate mass displacement of an ascending retrocecal appendix (arrows). The posterior wall of the proximal ascending colon is grossly intact.

(Reproduced from Meyers and Oliphant.11)

Retrocecal Appendix

Fig. 15—35. Extraperitoneal appendicitis.

Lateral view. The extraperitoneal nature of the inflammatory process associated with an ascending retrocecal appendix is revealed by the predominant involvement of the TM-TO row (large arrows). The posterior border of the TO-TL row is relatively unaffected (small arrows).

(Reproduced from Meyers et al.5)

Badania Kontrastowe Dolnego Odcinka

Fig. 15—36. Extraperitoneal appendicitis.

Oblique view of barium enema study demonstrates anterior and medial displacement of the cecum and proximal ascending colon by a large abscess secondary to a perforated retrocecal appendix. The appendix is not opacified, but note the posterior position of the ileocecal valve.

Fig. 15-37. Extraperitoneal appendicitis.

(a) A prominent fixed irregular mass involves the posterolateral contour of the ascending colon, accompanied by some deformity of the opposing haustra.

(b and c) Associated inflammatory findings are suggested by the frequent spastic changes, producing further narrowing of the lumen over varying lengths. Minute sinus tracts extend from the tip of an ascending retrocecal appendix. (Reproduced from Meyers and Oliphant.11)

Intraperitoneal Sinus

Fig. 15—38. Extraperitoneal appendicitis.

Supine study demonstrates extrinsic flattening of the medial border of the TM-TO haustral row of the ascending colon (arrows). This change localizes the primary process to the extraperitoneal space. There is reflux into the terminal ileum but no opacification of the appendix.

Fig. 15—38. Extraperitoneal appendicitis.

Supine study demonstrates extrinsic flattening of the medial border of the TM-TO haustral row of the ascending colon (arrows). This change localizes the primary process to the extraperitoneal space. There is reflux into the terminal ileum but no opacification of the appendix.

Extraperitoneal Space

Fig. 15—39. Extraperitoneal appendicitis.

(a) CT demonstrates an inflammatory mass (M) in the right anterior pararenal space below the level of the kidney. The ascending colon, filled with oral contrast medium, shows irregular bowel-wall thickening posteriorly due to inflammatory edema (large arrow). There is associated thickening of the lateroconal and anterior renal fasciae (small arrows).

(b) A barium enema study performed 2 years earlier demonstrates a retrocecal position of the appendix. (Reproduced from Feldberg et al.16)

Retrocecal Subhepatic

Fig. 15—40. Retrocecal appendiceal abscess and pylephlebitis.

(a) CT reveals an abscess (arrows) secondary to a perforated retrocecal appendix and suspicion of thrombosis of the superior mesenteric vein (arrowheads).

(b) Transverse intraoperative ultrasound scan shows a thrombosed and thickened extrahepatic portal vein (P). Numerous venous collaterals (paired arrowheads) are present around the vein in the hepatoduodenal ligament. A = abdominal aorta.

(Reproduced from Farin et al.17)

Peritoneal Subhepatic

Fig. 15—41. Ascending subhepatic appendix.

(a) Plain film. Tubular radiolucency (arrows) is directed superiorly and medially beneath the edge of the liver, anterior to the right kidney.

(b) Barium enema study verifies the position of the appendix and its association with a mobile undescended cecum.

(Reproduced from Meyers and Oliphant.11)

Fig. 15—41. Ascending subhepatic appendix.

(a) Plain film. Tubular radiolucency (arrows) is directed superiorly and medially beneath the edge of the liver, anterior to the right kidney.

(b) Barium enema study verifies the position of the appendix and its association with a mobile undescended cecum.

(Reproduced from Meyers and Oliphant.11)

Subhepatic Cecum Image

Fig. 15—42. Subhepatic ascending appendix.

(a) Barium enema shows a nondescended subhepatic cecum and ascending appendix.

(b) CT displays the position of the retroperitoneal, ascending retrocecal appendix (arrows) anterior to the right kidney. (Reproduced from Feldberg et al.16)

Fig. 15—42. Subhepatic ascending appendix.

(a) Barium enema shows a nondescended subhepatic cecum and ascending appendix.

(b) CT displays the position of the retroperitoneal, ascending retrocecal appendix (arrows) anterior to the right kidney. (Reproduced from Feldberg et al.16)

Appendicitis Enema

Fig. 15-43. Retrocolic appendicitis with subhepatic abscess.

(a) A retrocolic appendix, collapsed and with a thickened wall, is present (arrow) along with periappendicular inflammatory changes.

(b) Secondary to perforation of the subhepatic appendix, a collection of air (arrow) with associated inflammatory changes has developed beneath the right lobe of the liver (RL) lateral to the hepatic flexure of the colon (C).

(Courtesy of Emil Balthazar, M.D., Bellevue Hospital, New York University School of Medicine, New York, NY).

Fig. 15-43. Retrocolic appendicitis with subhepatic abscess.

(a) A retrocolic appendix, collapsed and with a thickened wall, is present (arrow) along with periappendicular inflammatory changes.

(b) Secondary to perforation of the subhepatic appendix, a collection of air (arrow) with associated inflammatory changes has developed beneath the right lobe of the liver (RL) lateral to the hepatic flexure of the colon (C).

(Courtesy of Emil Balthazar, M.D., Bellevue Hospital, New York University School of Medicine, New York, NY).

Fig. 15-44. Extraperitoneal appendicitis with abscess formation across Petit's triangle.

Fulminant inflammatory changes secondary to perforation of an ascending retrocecal extraperitoneal appendix have led to abscess formation in the right psoas muscle, deep in the flank, and striking extension via Petit's triangle to the subcutaneous tis-

Fig. 15-44. Extraperitoneal appendicitis with abscess formation across Petit's triangle.

Fulminant inflammatory changes secondary to perforation of an ascending retrocecal extraperitoneal appendix have led to abscess formation in the right psoas muscle, deep in the flank, and striking extension via Petit's triangle to the subcutaneous tis-

Anterior Extraperitoneal Hematoma

Fig. 15—45. Extraperitoneal hematoma.

(a) The descending colon is medially displaced, but significantly, there is no pressure effect on its lateral TO-TL row.

(b) Oblique view shows some anterior displacement but with definite straightening of the contours of the posterior TM-TO row (arrows) by the mass. This finding localizes the mass to the extraperitoneal space and distinguishes it from an intraperitoneal fluid mass occupying the lateral paracolic gutter. (Reproduced from Meyers et al.5)

Fig. 15—45. Extraperitoneal hematoma.

(a) The descending colon is medially displaced, but significantly, there is no pressure effect on its lateral TO-TL row.

(b) Oblique view shows some anterior displacement but with definite straightening of the contours of the posterior TM-TO row (arrows) by the mass. This finding localizes the mass to the extraperitoneal space and distinguishes it from an intraperitoneal fluid mass occupying the lateral paracolic gutter. (Reproduced from Meyers et al.5)

Peritoneal Seeding

Malignant Seeding

Malignant intraperitoneal seeding, following the pathways of flow of ascitic fluid as described in Chapter 4, tends to localize to the TO-TL row of the ascending colon. Embolic metastases, in accord with the intramural arterial distribution, also tend to develop in the antimesenteric row of haustra.

Duplication of the Colon

Duplications of the colon have a well-developed smooth muscle layer, are lined by colonic mucosa, and are adherent to and often communicate with the large intes-tine.18 They typically displace the colon along the mes-enteric border and thus lie in relationship to the TM-TL haustral row of the ascending or descending colon and the TM-TO row of the transverse colon (Figs. 15-46 and 15-47). Because the two colons share a common blood supply and in most cases there is only a single mesentery, resection of the supernumerary colon or microcolon is usually impossible.19'20

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Responses

  • Lena
    Can the descending colon be fecal laden?
    3 years ago
  • maximilian
    What marks the border between intraperitoneal and extraperitoneal?
    3 years ago
  • KAROLIINA STENVALL
    What is extraperitoneal inflammation?
    2 years ago
  • samuel temesgen
    What is the difference between intaperitoneal and extraperitoneal?
    1 year ago
  • sofia
    What is difference between intra and extraperitoneal?
    6 months ago

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