•
Diagnostic Radiology
Renal Fascia in Urinary Tract Disease 1 Zoran Barbaric, M.D. The renal fascia is rarely detected on excretory urograms. When seen, it is usually associated with disease processes such as focal renal scarring, acute renal infection, renal calculi, and intrarenal and perirenal masses. In all cases of normal appearing kidneys with visualization of the renal fascia, undetected renal disease should be suspected. INDEX TERMS:
Kidneys, diseases
Radiology 118:561-565, March 1976
•
• fascia. "High-dose urography" was usually employed. Nephrotomography was used for the majority of patients over 35 years of age. The renal fascia could not be detected on the vast majority of excretory urograms. In only 37 cases was it clearly visualized, usually as a pencil-thin line and less frequently thicker (up to about 2 mm). It was always seen parallel to the renal outline unless displaced by a mass and could usually be identified lateral to the renal outline on the frontal projection or, less often, anterior or posterior to the kidney in the appropriate oblique projection. Analysis of the 37 cases in which the renal fascia was seen on excretory urography is presented in TABLE I. In only 4 cases was it seen around radiographically normal kidneys. The first patient had hypertension (Fig. 2), the second cystinuria, renal calculi in the contralateral kidney, and a history of passing stones from the ipsilateral kidney (Fig. 3). The vast majority of patients had focal parenchymal scarring with blunted calyces, due either to chronic focal pyelonephritis or to refluxing uropathy. The renal fascia was usually seen along the entire lateral border of the scarred kidney (Fig. 4). Even more frequently, it was thickened and seen just opposite to the parenchymal scars (Fig. 5). Rarely was it present opposite the blunted calyx and without identifiable renal scarring (Fig. 6). The fascia was seen less frequently in other disease states; these included 2 cases of polycystic kidney disease, the first complicated by a renal calculus (Fig. 7), the second by pyuria probably caused by an infected cyst. Thickened renal fascia was clearly seen in a case of gas-forming acute pyelonephritis, with gas localized in the perinephric space (Fig. 8). One patient had renal papillary necrosis, proved by history and biopsy to be due to analgesic abuse (Fig. 9). It is of interest that a number of patients showed renal calculi either at the time of the study or before (TABLE II).
ISPLACEMENT of the renal fascia from its usual anatomical position aids significantly in the diagnosis of perirenal hematomas, abscesses, and other masses (2). The fascia plays a significant role in compartmentalization of the retroperitoneal space, restricting the flow of retroperitoneal fluid collections, and inhibiting the retroperitoneal spread of renal infections (3). Because of the radiological and clinical importance of the renal fascia, a prospective one-year study was conducted to determine (a) its normal appearance; (b) how frequently it can be detected; and (c) what diseases are associated with abnormally appearing or displaced renal fascia.
D
ANATOMY OF THE RENAL FASCIA
The renal fascia is a thin layer of connective tissue surrounded by pararenal adipose tissue (Fig. 1) which envelops the kidney, suprarenal glands, perirenal adipose tissue, and capsular vessels (4). Anterior and posterior renal fascial planes fuse superiorly, adhering to the diaphragmatic fascia; laterally they fuse to form the lateroconal fascia, which joins the peritoneum (3). The layers meet medially only along the more inferior margin. At the level of the renal pelvis, the posterior layer fuses with the psoas fascia, and both layers blend with the retroperitoneal connective tissue around the great vessels. The layers meet and fuse inferiorly with the iliac fascia. Three spaces are thus formed: (a) the perirenal space between the renal capsule and the renal fascia; (b) the anterior pararenal space between the anterior renal fascial plane and the peritoneum; and (c) the posterior para renal space between the posterior renal fascial plane and the transversalis fascia. This space communicates with the properitoneal fat. CASE MATERIAL
All excretory urograms obtained from adults at the University of Rochester Medical Center during a oneyear period (about 4,000) were carefully examined at the time of the study for radiographic evidence of renal
DISCUSSION
The renal fascia is rarely associated with radiographically normal kidneys. Despite the fact that it is bordered
1 From the Department of Radiology, University of Rochester School of Medicine and Dentistry, Rochester, N. Y. Accepted for publication in August 1975. ss
561
562
ZORAN BARBARIC
FIG. 1.
Schematic drawing of the renal fascial. 1 = transversalis fascia; 2
March 1976
= posterior renal fascial plane; 3
= anterior renal fascial plane; 4 = lateroconal fascia; 5 = renal capsule; 6 = peritoneum; a = posterior pararenal space; b = perirenal space; c = anterior pararenal space; d = properitoneal fat. on both sides by the radiolucent perinephric and paranephric fat, it is too thin and has too meager a blood supply to be visualized on an excretory urogram. It is not unusual for renal infections to extend beyond the renal capsule into the perinephric space (1); it is conceivable that this extension of the renal process can in-
volve the renal fascia as well. Thickening and hypervascularity are responses to inflammation (2), and these probably remain as permanent sequelae, even after the primary renal infection has become quiescent and the renal parenchyma has become scarred. The great majority of our patients in whom the renal fascia was visu-
FIG. 2. Left kidney in the left posterior oblique projection. Note the line of fusion between the posterior renal fascial plane (open arrow) and the anterior renal fascial plane (black arrow). FIG. 3. Left kidney in the left posterior oblique projection: anterior renal fascial plane.
Vol. 118
RENAL FASCIA IN URINARY TRACT DISEASE
563
Diagnostic Radiology
FIG. 4. Left kidney, anteroposterior projection: focal parenchymal scarring with blunted calyces. Note the renal fascia along the lateral renal margin. FIG. 5. Left kidney, anteroposterior projection: focal parenchymal scarring with blunted calyces. There is thickened renal fascia opposite the scars.
FIG. 6. Right kidney, anteroposterior projection: caliceal blunting. no parenchymal scarring. The fascia is opposite the blunted calyx.
FIG. 7. Left kidney: polycystic kidney disease and distal left ureteral obstruction due to a ureteral calculus.
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37.
(P.V.) (H.D.) (P.R.) (N.W.) (C.M.) (N.D.) (C.G.) (K.M.) (K.V.) (J.H.) (M.e.) (S.H.) (S.R.) (W.A.) (S.L.) (H.S.) (W.E.) (B.D.) (C.F.) (K.R.) (B.D.) (E.J.) (A.C.) (M.P.) (W.H.) (F.J.) (G.G.) (M.A.) (B.D.) (H.W.) (S.W.) (S.K.) (P.M.) (E.M.) (D.S.) (T.H.) (C. B.}
Age (yr.)
48 51 61
60 85 26 50 40 14 21 48 59 59 60 35 30 60 32 78 80 52 55 64 46 70 76 23 55 44 50 59 71 60 56 18 61
(Fig. 2)
(Fig. 3)
(Fig. 7)
(Fig. 5) (Fig. 9)
(Fig. 4)
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History of Urinary PapilMedullary Ureteral Chronic Tract History lary NecroObRenal I nof Sponge Normal sis struction Failure fection Calculus Kidney Kidney
-----~----------------------------------------------
X
------------------------------------
Case
Analysis of 37 Cases
Acute Urinary Ileal PolyTract Loop Small Focal Renal Smooth cystic InDiverRenal Blunted Renal Surgery Calyces Calculi Scarring Mass Kidneys Kidneys fection sion
Table I:
o
m
....
CD
tr
f
o·
> JJ
OJ
> JJ
CD
> z
JJ
N
0
~
01 0>
565
RENAL FASCIA IN URINARY TRACT DISEASE
Vol. 118
FIG. 9. Right kidney: parenchymal scarring.
FIG. 8. Right kidney: acute gas-forming pyelonephritis with perirenal extension. The renal fascia is thickened and in some places displaced from the renal margin.
Table II:
analgesic nephropathy, papillary necrosis,
alized had radiographically identifiable pathological processes within the kidney. Whenever the renal fascia is visualized but the kidney appears normal, one should suspect that an undetected renal abnormality is present. Department of Radiology University of Rochester School of Medicine and Dentistry Rochester, N. Y. 14642
Summary of Case Findings
Scarred kidneys with or without blunted calyces Scarred kidneys with or without blunted calyces with calculi Small kidneys (smooth) Mass alone Polycystic kidney disease Acute pyelonephritis Heminephrectomy Medullary sponge kidney Normal TOTAL
Diagnostic Radiology
17 7
3 1 2 1 1 1 4
37
REFERENCES 1. Evans JA, Meyers MA, Bosniak MA: Acute renal and perirenal infections. Semin Roentgenol 6:274-291, Jul 1971 2. Meyers MA, Whalen JP, Evans JA: Diagnosis of perirenal and subcapsular masses. Anatomic-radiologic correlation. AM J RoentgenoI121:523-538, Jul 1974 3. Meyers MA, Whalen JP, Peelle K, et al: Radiologic features of extraperitoneal effusions. Radiology 104:249-257, Aug 1972 4. Mitchell GAG: The renal fascia. Br J Surg 37:257-266, Jan 1950
Diagnostic Radiology
Renal Fascia in Urinary Tract Disease 1 Zoran Barbaric, M.D. The renal fascia is rarely detected on excretory urograms. When seen, it is usually associated with disease processes such as focal renal scarring, acute renal infection, renal calculi, and intrarenal and perirenal masses. In all cases of normal appearing kidneys with visualization of the renal fascia, undetected renal disease should be suspected. INDEX TERMS:
Kidneys, diseases
Radiology 118:561-565, March 1976
•
• fascia. "High-dose urography" was usually employed. Nephrotomography was used for the majority of patients over 35 years of age. The renal fascia could not be detected on the vast majority of excretory urograms. In only 37 cases was it clearly visualized, usually as a pencil-thin line and less frequently thicker (up to about 2 mm). It was always seen parallel to the renal outline unless displaced by a mass and could usually be identified lateral to the renal outline on the frontal projection or, less often, anterior or posterior to the kidney in the appropriate oblique projection. Analysis of the 37 cases in which the renal fascia was seen on excretory urography is presented in TABLE I. In only 4 cases was it seen around radiographically normal kidneys. The first patient had hypertension (Fig. 2), the second cystinuria, renal calculi in the contralateral kidney, and a history of passing stones from the ipsilateral kidney (Fig. 3). The vast majority of patients had focal parenchymal scarring with blunted calyces, due either to chronic focal pyelonephritis or to refluxing uropathy. The renal fascia was usually seen along the entire lateral border of the scarred kidney (Fig. 4). Even more frequently, it was thickened and seen just opposite to the parenchymal scars (Fig. 5). Rarely was it present opposite the blunted calyx and without identifiable renal scarring (Fig. 6). The fascia was seen less frequently in other disease states; these included 2 cases of polycystic kidney disease, the first complicated by a renal calculus (Fig. 7), the second by pyuria probably caused by an infected cyst. Thickened renal fascia was clearly seen in a case of gas-forming acute pyelonephritis, with gas localized in the perinephric space (Fig. 8). One patient had renal papillary necrosis, proved by history and biopsy to be due to analgesic abuse (Fig. 9). It is of interest that a number of patients showed renal calculi either at the time of the study or before (TABLE II).
ISPLACEMENT of the renal fascia from its usual anatomical position aids significantly in the diagnosis of perirenal hematomas, abscesses, and other masses (2). The fascia plays a significant role in compartmentalization of the retroperitoneal space, restricting the flow of retroperitoneal fluid collections, and inhibiting the retroperitoneal spread of renal infections (3). Because of the radiological and clinical importance of the renal fascia, a prospective one-year study was conducted to determine (a) its normal appearance; (b) how frequently it can be detected; and (c) what diseases are associated with abnormally appearing or displaced renal fascia.
D
ANATOMY OF THE RENAL FASCIA
The renal fascia is a thin layer of connective tissue surrounded by pararenal adipose tissue (Fig. 1) which envelops the kidney, suprarenal glands, perirenal adipose tissue, and capsular vessels (4). Anterior and posterior renal fascial planes fuse superiorly, adhering to the diaphragmatic fascia; laterally they fuse to form the lateroconal fascia, which joins the peritoneum (3). The layers meet medially only along the more inferior margin. At the level of the renal pelvis, the posterior layer fuses with the psoas fascia, and both layers blend with the retroperitoneal connective tissue around the great vessels. The layers meet and fuse inferiorly with the iliac fascia. Three spaces are thus formed: (a) the perirenal space between the renal capsule and the renal fascia; (b) the anterior pararenal space between the anterior renal fascial plane and the peritoneum; and (c) the posterior para renal space between the posterior renal fascial plane and the transversalis fascia. This space communicates with the properitoneal fat. CASE MATERIAL
All excretory urograms obtained from adults at the University of Rochester Medical Center during a oneyear period (about 4,000) were carefully examined at the time of the study for radiographic evidence of renal
DISCUSSION
The renal fascia is rarely associated with radiographically normal kidneys. Despite the fact that it is bordered
1 From the Department of Radiology, University of Rochester School of Medicine and Dentistry, Rochester, N. Y. Accepted for publication in August 1975. ss
561
562
ZORAN BARBARIC
FIG. 1.
Schematic drawing of the renal fascial. 1 = transversalis fascia; 2
March 1976
= posterior renal fascial plane; 3
= anterior renal fascial plane; 4 = lateroconal fascia; 5 = renal capsule; 6 = peritoneum; a = posterior pararenal space; b = perirenal space; c = anterior pararenal space; d = properitoneal fat. on both sides by the radiolucent perinephric and paranephric fat, it is too thin and has too meager a blood supply to be visualized on an excretory urogram. It is not unusual for renal infections to extend beyond the renal capsule into the perinephric space (1); it is conceivable that this extension of the renal process can in-
volve the renal fascia as well. Thickening and hypervascularity are responses to inflammation (2), and these probably remain as permanent sequelae, even after the primary renal infection has become quiescent and the renal parenchyma has become scarred. The great majority of our patients in whom the renal fascia was visu-
FIG. 2. Left kidney in the left posterior oblique projection. Note the line of fusion between the posterior renal fascial plane (open arrow) and the anterior renal fascial plane (black arrow). FIG. 3. Left kidney in the left posterior oblique projection: anterior renal fascial plane.
Vol. 118
RENAL FASCIA IN URINARY TRACT DISEASE
563
Diagnostic Radiology
FIG. 4. Left kidney, anteroposterior projection: focal parenchymal scarring with blunted calyces. Note the renal fascia along the lateral renal margin. FIG. 5. Left kidney, anteroposterior projection: focal parenchymal scarring with blunted calyces. There is thickened renal fascia opposite the scars.
FIG. 6. Right kidney, anteroposterior projection: caliceal blunting. no parenchymal scarring. The fascia is opposite the blunted calyx.
FIG. 7. Left kidney: polycystic kidney disease and distal left ureteral obstruction due to a ureteral calculus.
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37.
(P.V.) (H.D.) (P.R.) (N.W.) (C.M.) (N.D.) (C.G.) (K.M.) (K.V.) (J.H.) (M.e.) (S.H.) (S.R.) (W.A.) (S.L.) (H.S.) (W.E.) (B.D.) (C.F.) (K.R.) (B.D.) (E.J.) (A.C.) (M.P.) (W.H.) (F.J.) (G.G.) (M.A.) (B.D.) (H.W.) (S.W.) (S.K.) (P.M.) (E.M.) (D.S.) (T.H.) (C. B.}
Age (yr.)
48 51 61
60 85 26 50 40 14 21 48 59 59 60 35 30 60 32 78 80 52 55 64 46 70 76 23 55 44 50 59 71 60 56 18 61
(Fig. 2)
(Fig. 3)
(Fig. 7)
(Fig. 5) (Fig. 9)
(Fig. 4)
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History of Urinary PapilMedullary Ureteral Chronic Tract History lary NecroObRenal I nof Sponge Normal sis struction Failure fection Calculus Kidney Kidney
-----~----------------------------------------------
X
------------------------------------
Case
Analysis of 37 Cases
Acute Urinary Ileal PolyTract Loop Small Focal Renal Smooth cystic InDiverRenal Blunted Renal Surgery Calyces Calculi Scarring Mass Kidneys Kidneys fection sion
Table I:
o
m
....
CD
tr
f
o·
> JJ
OJ
> JJ
CD
> z
JJ
N
0
~
01 0>
565
RENAL FASCIA IN URINARY TRACT DISEASE
Vol. 118
FIG. 9. Right kidney: parenchymal scarring.
FIG. 8. Right kidney: acute gas-forming pyelonephritis with perirenal extension. The renal fascia is thickened and in some places displaced from the renal margin.
Table II:
analgesic nephropathy, papillary necrosis,
alized had radiographically identifiable pathological processes within the kidney. Whenever the renal fascia is visualized but the kidney appears normal, one should suspect that an undetected renal abnormality is present. Department of Radiology University of Rochester School of Medicine and Dentistry Rochester, N. Y. 14642
Summary of Case Findings
Scarred kidneys with or without blunted calyces Scarred kidneys with or without blunted calyces with calculi Small kidneys (smooth) Mass alone Polycystic kidney disease Acute pyelonephritis Heminephrectomy Medullary sponge kidney Normal TOTAL
Diagnostic Radiology
17 7
3 1 2 1 1 1 4
37
REFERENCES 1. Evans JA, Meyers MA, Bosniak MA: Acute renal and perirenal infections. Semin Roentgenol 6:274-291, Jul 1971 2. Meyers MA, Whalen JP, Evans JA: Diagnosis of perirenal and subcapsular masses. Anatomic-radiologic correlation. AM J RoentgenoI121:523-538, Jul 1974 3. Meyers MA, Whalen JP, Peelle K, et al: Radiologic features of extraperitoneal effusions. Radiology 104:249-257, Aug 1972 4. Mitchell GAG: The renal fascia. Br J Surg 37:257-266, Jan 1950
