Lateroconal Fascia Research Articles

Renal fascial pathway: posterior extension of pancreatic effusions within the anterior pararenal space.

Retrorenal extension of pancreatic effusion or phlegmon associated with pancreatitis has been described frequently and is generally considered to represent extension of these processes from the anterior into the posterior pararenal space. A series of meticulous cadaveric dissections (n = 8) and a review of a large number of patients with pancreatitis (n = 53) show that these posterior collections actually represent extension of pancreatitis from the anterior pararenal space to a potential space between the laminae of the posterior renal fascia. Of 40 patients with posterior extension of pancreatic effusion or phlegmon, interfascial involvement was observed in all 40 and was bilateral in nine (23%). True involvement of the posterior pararenal space was uncommon, as was extension into the perirenal space. This phenomenon appears as a continuum of the well-described thickening of the renal fascia secondary to pancreatitis. It can be explained by new observations of the relationships between the fascia of Gerota and the lateroconal fascia.

More on the roentgenology of the paracolonic gutter.

The studies of Whalen and his colleagues (1, 2) on the retroperitoneal fatty continuum show that the carcass of radiologic gross anatomy, bequeathed to us by earlier workers, still harbors savory morsels available to the diligent plucker. In addition to its well recognized visceral and neurovascular components, the retroperitoneal fatty layer contains several fascial planes such as the anterior and posterior layers of the renal (Gerota) fascia with a lateral prolongation from their point of fusion, the lateroconal fascia, which merges into the parietal peritoneum. Detailed anatomic study of these fasciae departs significantly from the usual textbook concepts (3, 4). At times, radiologic study of these fasciae yields information of real value in detecting disease of the kidney and adrenal (1). For several years we have been observing a hair-line shadow of water density in each flank, contrasted by fat on each side. Taking cue from Frimann-Dah1 (5), we considered this line the opposed peritoneal surfaces, marginated by retroperitoneal fat laterally and by serosal fat medially. This explanation has never been proved by marking the flank peritoneum with clips during surgery, despite a patient wait for a patient who presented preoperative visualization of this line. One of Whalen's patients (2) with massive ascites shows the line. At least in this patient, the mechanism of the radiologic visualization of the line given above, namely, opposition of visceral and parietal peritoneum, can not obtain, because filling of the paracolonic gutter by the ascitic fluid should obliterate the medial fatty contrast and should result in the disappearance of the line. The line, at least in this patient, must therefore be caused by another retroperitoneal fascial plane, lateral to the peritoneum, and marginated by retroperitoneal fat on both sides. Despite any change in concept of the radiologic mechanism of this line, at present an academic consideration, the validity of the radiologically thickened colonic “wall” continues unchanged as an indicator of (a) truly thickened colonic wall such as occurs in infarction, infection, or tumor (6), (b) a thin layer of blood lying in the paracolonic gutter, the earliest and best sign of ruptured viscus in our experience (7), and (c) retroperitoneal bleeding that has infiltrated the lateral serosa of the colon (8).

The extraperitoneal perivisceral fat pad. II. Roentgen interpretation of pathological alterations.

THE PURPOSE of this paper is to describe the roentgen manifestations of alterations of the normal anatomy of the extraperitoneal perivisceral fat pad and to emphasize that both intra- and extraperitoneal pathologic processes can affect the e. p. f. p. Intraperitoneal Disease A. Fluid: Intraperitoneal fluid in the upper abdomen frequently manifests itself radiologically by collecting adjacent to the properitoneal fat line as a linear density, displacing the colon medially and thinning the properitoneal fat. This shadow has been called the “flank stripe” (5). In addition, the medial margin of the “hepatic angle” may be lost (Fig. 1). What is the explanation for the loss of the hepatic angle by intraperitoneal fluid if the shadow of the hepatic angle is cast by the liver's contrasting with extraperitoneal Iat?3 The great pliability of the e. p. f. p. explains this finding. The intraperitoneal fluid fills the peritoneal recess about the posterior inferior portions of the liver, widening and blunting it. The fluid also displaces the liver medially and anteriorly. The pliable e. p. f. p. which encases this medial portion of the hepatic angle is thinned and flattened (similarly to the properitoneal fat line) by the combined fluid and liver in the peritoneal recess. The resultant anterior-posterior soft-tissue-fat interface disappears, rendering the hepatic angle invisible to the roentgen ray (Figure 2). A similar explanation applies to the loss of the splenic angle with intraperitoneal fluid. B. Mass: Intraperitoneal masses which significantly indent the e. p. f. p. may be visualized on plain supine films. These masses are located posteriorly in the peritoneum (Fig. 3). Anteriorly situated intraperitoneal masses are notoriously difficult to visualize except as they displace gas-containing portions of the gastrointestinal tract. The difficulty in demonstrating hydrops of the gallbladder on plain films is an example of this. Extraperitoneal Disease A. Fluid: Extraperitoneal fluid infiltrates the e. p. f. p. and by increasing the fat's density negates its contrast, causing loss of the normal shadows. The obliteration of the psoas and renal shadows by extraperitoneal fluid are well known radiological signs. Less well known manifestations of extraperitoneal fluid should, however, be emphasized. Extraperitoneal fluid in the posterior right upper quadrant may dissect superiorly and laterally. It can obliterate the hepatic angle by infiltrating the properitoneal fat laterally and, medially, the e. p. f. p. which juxtaposes the medial inferior border of the liver angle (Fig. 4). In addition, when the fluid is loculated in the perirenal space medial to the lateroconal fascia and without extension into the pararenal space, the hepatic angle can be lost, even though the properitoneal fat line is intact.