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Renal Anatomy for Endourologic Stone Removal
0022-534 7/83/1304-064 7$02.00/0 Vol. 130, October Printed in U.S.A.
THE JOURNAL OF UROLOGY
Copyright© 1983 by The Williams & Wilkins Co.
Original Articles RENAL ANATOMY FOR ENDOUROLOGIC STONE REMOVAL KEITH W. KAYE From the Department of Urologic Surgery, University of Minnesota Medical School, Minneapolis, Minnesota
ABSTRACT
A transparent kidney model that shows the position of the calices in relation to the surface can be fabricated easily and is invaluable in planning percutaneous nephrostolithotomies and other endourological procedures. For endourological removal of renal calculi (nephrostolithotomy) to succeed the operator must have an accurate 3-dimensional mental image of the location of the stone. However, many practitioners have difficulty imagining the exact position of the calices and visualizing the collecting system in 3 dimensions on the basis of the excretory urogram (IVP). To remedy
METHOD
The perirenal and peripelvic fat, and the blood vessels are removed from a cadaver kidney and a mixture of RTV-11 silicone rubber compound and catalyst* is injected into the ureter to fill the renal pelvis and caliceal system. After this material has set (approximately 30 minutes with STO curing p
Posterior calyces
20° " \ .......... Brodel's line of incision
···········
"""''---+-+-- Frontal plane of kidney
Anterior calyces
FIG. 1. Anterior view of completed model of left kidney. Note especially appearance of anterior calices.
this situation a transparent kidney model was created within which the collecting system can be seen easily. The clinical and radiological aspects of renal anatomy highlighted by the use of a transparent kidney model are described. Accepted for publication March 4, 1983. Read at annual meeting of American Urological Association, Las Vegas, Nevada, April 17-21, 1983.
FIG. 2. a, transverse section of kidney shows arrangement of anterior (A) and posterior (P) rows of calices. b, diagram of collecting system shows anterior (2, 4 and 6) and posterior (3, 5 and 7) rows of calices.
agent) the kidney is immersed halfway in another batch of the same RTV-11 mixture in a deep plastic bowl. When this has * General Electric Co., RTV Products Department, Waterford, New York 12188.
647
648
KAYE Long axis of posterior calyces
~o·
/ ~ Percutaneous nephrostomy entering posterior calyx along Brodel's line of incision I
~
--I-/. lI
1 ~~/
r 1 :,,- ,,- /
Frontal plane of kidney 30 ,
Coronal plane of body
7
30'
/ / /
/
/ /
.....,;.,,, _ _ _..;;;._ _ _ _;;...._ _ _ _ _ _ _._Table top
FIG. 3. Site of percutaneous nephrostomy
hardened its surface is smeared with petroleum jelly to make it easier to separate the mold later, and a third batch of RTV-11 catalyst mixture is poured into the bowl until the kidney is submerged. After the compound has set the mold is turned out of the bowl and separated. The kidney tissue is cut away from the endocast of the collecting system and the mold, clean of tissue, then is reassembled with the endocast inside. The mold is filled with casting resin. After it has hardened the mold is removed, and the model is buffed and polished to provide a clear view of the renal collecting system (fig. 1). DISCUSSION
Although renal anatomy differs considerably from 1 person to another the transparent kidney model has been of considerable use when planning nephrostolithotomy, teaching endourology and in mental translation of 2-dimensional radiographic images into 3-dimensional reality. Caliceal arrangement. In the classic type of kidney with a true renal pelvis there are 4 to 12 (most often 8) calices arranged in a generally uniform pattern that can be understood best in
relation to the frontal (coronal) plane of the kidney, which passes through the renal hilus and the most convex surface of the lateral margin (fig. 2, a). In the upper and lower poles the calices usually are compound and often lie at various angles within the frontal plane (fig. 2, b, 1 and 8). The remaining calices are arranged in 2 distinct rows, 1 in the anterior half (fig. 2, b, 2, 4 and 6) and 1 in the posterior half (fig. 2, b, 3, 5 and 7) of the kidney. The anterior calices usually form an angle of approximately 70 degrees with the frontal plane and, thus, are directed almost straightforward facing the anterior surface of the kidney. The posterior calices usually form an angle of approximately 20 degrees from the frontal plane and face a line slightly posterior to the lateral convex border of the kidney (fig. 2, a). Comparison with the !VP. On a standard IVP the anterior row of calices usually is seen more peripherally and laterally as cup-shaped structures, whereas the posterior row is seen more medially and frontally as round concentrations of contrast medium. This is understandable if one remembers that in situ the hilar aspect of the kidney is rotated medially on the psoas major muscle, which rotates the lateral renal margin posteriorly some 30 to 45 degrees behind the coronal plane (fig. 3). Therefore, the anterior calices are swung out laterally and are seen from the side, whereas the posterior calices move medially to point almost directly backwards and are seen end on. Positioning the patient for percutaneous nephrostomy. A good knowledge of renal anatomy is essential for a well placed percutaneous nephrostomy. Many radiologists prefer to puncture the kidney just posterior to its lateral margin and to enter the collecting system through the infundibulum of the lower most calix of the posterior row (fig. 2, b, 7). Thus, the needle enters the renal parenchyma in or near the avascular plane of Brodel's line of incision (fig. 2, a). If the patient is lying prone on the fluoroscopy table and tilted upward 30 degrees on the operative side the posterior row of calices will project almost vertically upward, presenting an easy target for the percutaneous needle (fig. 3).
THE JOURNAL OF UROLOGY
Copyright© 1983 by The Williams & Wilkins Co.
Original Articles RENAL ANATOMY FOR ENDOUROLOGIC STONE REMOVAL KEITH W. KAYE From the Department of Urologic Surgery, University of Minnesota Medical School, Minneapolis, Minnesota
ABSTRACT
A transparent kidney model that shows the position of the calices in relation to the surface can be fabricated easily and is invaluable in planning percutaneous nephrostolithotomies and other endourological procedures. For endourological removal of renal calculi (nephrostolithotomy) to succeed the operator must have an accurate 3-dimensional mental image of the location of the stone. However, many practitioners have difficulty imagining the exact position of the calices and visualizing the collecting system in 3 dimensions on the basis of the excretory urogram (IVP). To remedy
METHOD
The perirenal and peripelvic fat, and the blood vessels are removed from a cadaver kidney and a mixture of RTV-11 silicone rubber compound and catalyst* is injected into the ureter to fill the renal pelvis and caliceal system. After this material has set (approximately 30 minutes with STO curing p
Posterior calyces
20° " \ .......... Brodel's line of incision
···········
"""''---+-+-- Frontal plane of kidney
Anterior calyces
FIG. 1. Anterior view of completed model of left kidney. Note especially appearance of anterior calices.
this situation a transparent kidney model was created within which the collecting system can be seen easily. The clinical and radiological aspects of renal anatomy highlighted by the use of a transparent kidney model are described. Accepted for publication March 4, 1983. Read at annual meeting of American Urological Association, Las Vegas, Nevada, April 17-21, 1983.
FIG. 2. a, transverse section of kidney shows arrangement of anterior (A) and posterior (P) rows of calices. b, diagram of collecting system shows anterior (2, 4 and 6) and posterior (3, 5 and 7) rows of calices.
agent) the kidney is immersed halfway in another batch of the same RTV-11 mixture in a deep plastic bowl. When this has * General Electric Co., RTV Products Department, Waterford, New York 12188.
647
648
KAYE Long axis of posterior calyces
~o·
/ ~ Percutaneous nephrostomy entering posterior calyx along Brodel's line of incision I
~
--I-/. lI
1 ~~/
r 1 :,,- ,,- /
Frontal plane of kidney 30 ,
Coronal plane of body
7
30'
/ / /
/
/ /
.....,;.,,, _ _ _..;;;._ _ _ _;;...._ _ _ _ _ _ _._Table top
FIG. 3. Site of percutaneous nephrostomy
hardened its surface is smeared with petroleum jelly to make it easier to separate the mold later, and a third batch of RTV-11 catalyst mixture is poured into the bowl until the kidney is submerged. After the compound has set the mold is turned out of the bowl and separated. The kidney tissue is cut away from the endocast of the collecting system and the mold, clean of tissue, then is reassembled with the endocast inside. The mold is filled with casting resin. After it has hardened the mold is removed, and the model is buffed and polished to provide a clear view of the renal collecting system (fig. 1). DISCUSSION
Although renal anatomy differs considerably from 1 person to another the transparent kidney model has been of considerable use when planning nephrostolithotomy, teaching endourology and in mental translation of 2-dimensional radiographic images into 3-dimensional reality. Caliceal arrangement. In the classic type of kidney with a true renal pelvis there are 4 to 12 (most often 8) calices arranged in a generally uniform pattern that can be understood best in
relation to the frontal (coronal) plane of the kidney, which passes through the renal hilus and the most convex surface of the lateral margin (fig. 2, a). In the upper and lower poles the calices usually are compound and often lie at various angles within the frontal plane (fig. 2, b, 1 and 8). The remaining calices are arranged in 2 distinct rows, 1 in the anterior half (fig. 2, b, 2, 4 and 6) and 1 in the posterior half (fig. 2, b, 3, 5 and 7) of the kidney. The anterior calices usually form an angle of approximately 70 degrees with the frontal plane and, thus, are directed almost straightforward facing the anterior surface of the kidney. The posterior calices usually form an angle of approximately 20 degrees from the frontal plane and face a line slightly posterior to the lateral convex border of the kidney (fig. 2, a). Comparison with the !VP. On a standard IVP the anterior row of calices usually is seen more peripherally and laterally as cup-shaped structures, whereas the posterior row is seen more medially and frontally as round concentrations of contrast medium. This is understandable if one remembers that in situ the hilar aspect of the kidney is rotated medially on the psoas major muscle, which rotates the lateral renal margin posteriorly some 30 to 45 degrees behind the coronal plane (fig. 3). Therefore, the anterior calices are swung out laterally and are seen from the side, whereas the posterior calices move medially to point almost directly backwards and are seen end on. Positioning the patient for percutaneous nephrostomy. A good knowledge of renal anatomy is essential for a well placed percutaneous nephrostomy. Many radiologists prefer to puncture the kidney just posterior to its lateral margin and to enter the collecting system through the infundibulum of the lower most calix of the posterior row (fig. 2, b, 7). Thus, the needle enters the renal parenchyma in or near the avascular plane of Brodel's line of incision (fig. 2, a). If the patient is lying prone on the fluoroscopy table and tilted upward 30 degrees on the operative side the posterior row of calices will project almost vertically upward, presenting an easy target for the percutaneous needle (fig. 3).