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Equine Veterinary Journal ISSN 0425-1644 DOI: 10.1111/evj.12167
Experimental and Basic Research Studies
Ureteropyeloscopic anatomy of the renal pelvis of the horse S. G. PASQUEL, D. AGNEW†, N. NELSON‡, J. M. KRUGER‡, I. SONEA† and H. C. SCHOTT II* Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, USA † Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, USA ‡ Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, USA. *Correspondence email: [email protected]; Received: 20.03.13; Accepted: 02.08.13
Summary Reasons for performing study: Although the equine renal pelvis and terminal recesses have been described post mortem, little information exists about the endoscopic appearance of these structures in the living horse for guiding ureteropyeloscopy. Objectives: To further document the anatomy of the upper urinary collecting system, specifically the renal pelvis and terminal recesses, of the horse. Study design: Descriptive study of cadaver material. Methods: Kidneys were harvested from 10 horses. Magnetic resonance imaging was performed after distension of the renal pelvis with an elastomer casting material, followed by visual inspection of corrosion casts. Transurethral ureteropyeloscopy of the upper urinary tract was performed in 4 horses, followed by histological and immunohistochemical examination of the renal medulla and pelvis of 3 animals. Results: The equine renal pelvis was confirmed to be a funnel-shaped cavity, flattened dorsoventrally in the craniocaudal direction. Multiple papillary ducts (PDs) from the central part of the kidney open along a ∼3 cm long renal crest that protrudes into the renal pelvis, while PDs from each kidney pole open into 2 long (5–10 cm), narrow terminal recesses that terminate near either end of the renal crest. Openings of the terminal recesses narrow at their junction with the renal pelvis and could be visualised during ureteropyeloscopy in all horses. Minor anatomical variation of the renal crest and terminal recess openings was observed. Conclusions: Current endoscopic equipment can be used to visualise the renal pelvis but could not be advanced into the terminal recesses. The findings of this study will help guide future diagnostic and therapeutic ureteropyeloscopy. Keywords: horse; endoscopy; kidney; renal pelvis; terminal recess
Introduction Urethroscopy and cystoscopy have been performed in horses since the 1970s to examine the lower urinary tract [1–5]. However, evaluation of the upper urinary tract has largely been accomplished using indirect imaging techniques, including ultrasonography, i.v. and retrograde contrast pyelography, and nuclear scintigraphy [6–10]. In man, endoscopic examination of the ureter and renal pelvis (ureteropyeloscopy) has become a routine procedure for direct examination of the upper tract in patients with lithiasis, infection, neoplasia or haematuria [11–13]. Using long, flexible endoscopes with small diameters, ureteropyeloscopy is now possible in horses; however, knowledge of normal endoscopic anatomy of the equine upper urinary tract, specifically the renal pelvis, is a prerequisite for accurate diagnostic interpretation. The anatomy of collecting systems of the kidney varies widely across species. Anatomy textbooks describe the equine renal pelvis as a simple funnel-shaped dilation of the proximal ureter [14–18]. Opposite the outflow path of the ureter is a prominent, slightly concave ridge of tissue termed the renal crest [14–17]. Papillary ducts (PDs) from the central part of the kidney open onto the renal crest allowing urine to exit into the pelvis. In addition, 2 terminal recesses extend from the pelvis towards each kidney pole [14–18]. Papillary ducts from nephrons in the poles of the kidney open into these recesses. Illustrations and corrosion casts depict the terminal recesses to be tubular structures emanating from the renal pelvis [14–18] that might be accessible with a small diameter endoscope. The purpose of this study was to further investigate the anatomy of the upper urinary collecting system of the horse, specifically the renal pelvis and terminal recesses. In addition to direct examination of corrosion casts of the renal pelvis, a novel method using 3-dimensional (3D) reconstruction of magnetic resonance imaging (MRI) scans of proximal ureteral and renal pelvic casts was employed. The renal pelvis was also examined directly via ureteropyeloscopy. Finally, kidney sections were examined visually and microscopically and immunohistochemical labelling was performed to further describe the anatomy of the renal pelvis, terminal recesses, renal crest and inner medulla. Equine Veterinary Journal 45, Suppl. 45 (2013) 31–38 © 2013 EVJ Ltd
Materials and methods Horses studied and specimens collected Kidneys were harvested from 10 horses (7 geldings and 3 mares with a mean age of 6 ± 3 [s.d.] years), within 2 h of euthanasia. Horses were weighed (± 2 kg) on a scale and scored for body condition [19] immediately prior to euthanasia. All horses had normal renal function, assessed by production of concentrated urine and normal ultrasonographic appearance of the kidneys, and were subjected to euthanasia for reasons unrelated to this study. None of the horses studied had been administered nephrotoxic medications within the prior 30 days or had any procedure performed that may have affected renal structure or function. Ureteropyeloscopy was performed in 4 additional horses, 2 mares and 2 geldings with a mean age of 14 ± 9 years with normal renal function and normal ultrasonographic appearance of the kidneys. Immediately following ureteropyeloscopy, 3 of these horses (2 geldings and one mare) were subjected to euthanasia and their kidneys removed for sectioning, histology and immunohistochemistry. Both geldings were Thoroughbred racehorses donated due to chronic lameness; thus, nonsteroidal anti-inflammatory drugs had likely been administered to these horses in the prior several months, but neither had documented use of nephrotoxic medications within the preceding 2 weeks. The mare subjected to euthanasia had been receiving phenylbutazone (2.2 mg/kg bwt per os q. 12 h) for the previous 30 days for treatment of arthritis, while the other mare not subjected to euthanasia had no recent history of medication use. The study protocol and all procedures performed were approved by the Animal Care and Use Committee of Michigan State University.
Urethane hybrid elastomer cast preparation The kidneys and ∼15 cm of the proximal ureter were removed, dissected free of fat and other connective tissue, and weighed (± 10 g). Volume of the tissues was determined by water displacement (± 5 ml). After volume determination, a rapidly setting urethane hybrid elastomer (Bioplastic Corosion Polymer)a was infused using a 60 ml syringe and a plastic i.v. fluid
31
Ureteropyeloscopy in normal horses
3 4
S. G. Pasquel et al.
10
2 7
5 1
11
8
6 9
12
Fig 1: Three-dimensional reconstruction of elastomer within a left kidney detailing where measurements were made: 1. length of the cranial terminal recess; 2. length of caudal terminal recess; 3. renal crest length; 4. renal pelvis proximal diameter; 5. renal pelvis middle diameter; 6. renal pelvis distal diameter; 7. diameter of the pelvic end of the cranial terminal recess; 8. diameter of the midpoint of the cranial terminal recess; 9. diameter of the pole end of the cranial terminal recess; 10. diameter of the pelvic end of the caudal terminal recess; 11. diameter of the midpoint of the caudal terminal recess and 12. diameter of the pole end of the cranial terminal recess.
extension line placed into the ureter to fill the proximal ureter, renal pelvis and terminal recesses. All infusions were performed by the same investigator who held the free end of the ureter tightly around the extension line while elastomer was infused. Infusion was continued until the proximal ureter was fully distended, mild distension of the renal pelvis was visibly evident as subtle enlargement of the renal hilus and moderate resistance to further injection was appreciated. The extension line was removed as the ureter was ligated 5–10 cm from the hilus. The degree of pelvic/hilar distension and volume of elastomer infused (35–40 ml in all specimens) were standardised after attempts in 2 pilot horses (also subjected to euthanasia for reasons unrelated to this study) revealed that infusion with a larger volume and greater force resulted in disruption of the pelvis and extension of cast material into the renal parenchyma. After allowing the elastomer to harden for 15–20 min, T2-weighted MRI sequences of both kidneys (0.2 mm slices) were obtained (Magnetom Espree 1.5T)b with the pair of kidneys resting on their ventral surfaces. Two and 3D images of each kidney and the cast material within the renal pelvis and terminal recesses were reconstructed using commercial softwarec (Fig 1). Kidney volume was estimated after computer tracing and elimination of cast material. Additional measurements obtained from reconstructions of the casts included: diameter of the renal pelvis (craniocaudal direction at 3 locations), renal pelvis volume, renal crest length, length of the cranial and caudal terminal recesses, and diameter of the terminal recesses at 3 locations in a dorsal plane (Fig 1). After completion of the MRI scans, the kidneys were frozen for several days and after subsequent thawing, renal parenchyma was gently dissected away from the casts. The casts were then placed in a 1.0 N HNO3 solution until the remaining renal parenchyma could be rinsed-off to allow visual inspection of the casts.
urethra in mares or via the perineal urethrotomy incision in geldings. Once the ureteral orifice was visualised, a flexible guide wire (Weasel Wire, 0.035 in, standard hydrophilic, 150 cm)e was passed through the instrument channel and directed into the ureteral opening and advanced ∼10 cm. The index and middle fingers were used to grasp the end of the endoscope and manually guide it into the ureter. This procedure was easily accomplished in the 2 mares, but was more challenging in the 2 geldings. Consequently, a 1 ml conical plastic pipette tip (BioDot specific fit pipet tip)f was passed over the guide wire and into the distal ureter to dilate the ureteral orifices in the geldings [20]. Ureteral dilation allowed successful passage of the endoscope in 3 of 4 of the remaining ureters but one ureter was unable to be accessed. Further, the perineal urethrotomy incision was extended to ∼10 cm and a partial dorsal sphincterotomy had to be performed in both geldings to allow adequate manual access to the ureteral orifices. After the endoscope had been advanced ∼10 cm into the ureter, the guide wire was removed and isotonic saline was infused (10 ml/min) with a fluid pump through the channel of the endoscope to maintain dilation of the ureter. The endoscope was subsequently advanced without difficulty a further 50–60 cm to the renal pelvis, which was then explored. In 3 horses, phenol red (P353)g was administered (1 mg/kg bwt i.v.) to facilitate detection of urine excretion from PDs along the renal crest and from the openings of the cranial and caudal terminal recesses. After ureteropyeloscopy, the kidneys of the 3 horses subjected to euthanasia were collected for gross, histological and immunohistochemical examination.
Gross anatomy, histology and immunohistochemistry Within 2 h of euthanasia, harvested kidneys were infused with 60 ml of 10% formalin in a retrograde fashion through the ureter, in a manner similar to that used for elastomer infusion and the ureter ligated allowing the renal pelvis and terminal recesses to be fixed in a distended state. The kidneys were then submerged in 10% formalin. After 3 days of fixation, the kidneys were sectioned (5–10 mm slices) along a sagittal axis (Fig 2) and each section photographed. Subsections (0.5 cm thick x 2 cm long x 1.5 cm wide) of medulla, containing the terminal recesses or renal pelvis, were placed in tissue cassettes, sectioned at 4–5 μm and stained with haematoxylin and eosin. Additional 4–5 μm sections, adjacent to those examined by routine histology, were labelled with a murine monoclonal antibody against smooth muscle actin (αSMA), after being deparaffinised in xylene and hydrated. Heat-induced epitope retrieval was performed and endogenous peroxidase was blocked using a 3% hydrogen peroxide/methanol bath. After incubation with normal goat serum to limit nonspecific protein binding, sections were incubated with avidin and biotin for 15 min. Primary antibody slides were incubated for 60 min with a murine monoclonal
9
Lateral 8
10
7 6
11 5
Ureteropyeloscopy
Cranial
32
4 Caudal
Horses were restrained standing in stocks and sedated with detomidine hydrochloride (0.02 mg/kg bwt i.v.). An i.v. catheter was aseptically placed into the jugular vein. The tail was wrapped and pulled to the side, faeces were manually evacuated from the rectum and the perineum prepared as for cystoscopy (mares) or surgery (geldings). A urethral catheter was passed into the bladder of the geldings and a 7 cm vertical perineal urethrotomy was performed. In both sexes, 20 ml of a 2% lidocaine HCl solution were infused into the bladder through a bladder catheter for topical anaesthesia after emptying the bladder of urine. The urethral sphincter was subsequently manually dilated until the index and middle fingers of a hand within a sterile glove could be easily passed into the bladder and the ureteral orifices could be palpated [20]. The endoscope (GIF-N180 SlimSIGHT ultra-slim video gastroscope)d (110 cm working length, 4.9 mm outer diameter, 2.0 mm instrument channel, 120° field of view via angulation of 220/120°) was then passed into the bladder via the
12 3
13
2 14
1 15 16 Medial
Fig 2: Diagram of a left kidney showing the pattern used to section the kidney for gross anatomical and histological examination. Equine Veterinary Journal 45, Suppl. 45 (2013) 31–38 © 2013 EVJ Ltd
Ureteropyeloscopy in normal horses
S. G. Pasquel et al.
TABLE 1: Mean ± s.d. values (range) for kidney weight, kidney volume measured by water displacement and kidney volume estimated from MRI reconstructions in 10 horses Measurement
Left kidney
Right kidney
Weight (g) Volume (water displacement, cm3) Volume (MRI, cm3)
960 ± 130 (760–1200) 810 ± 140 (610–1060)
990 ± 180 (740–1400) 880 ± 180 (600–1240)*
820 ± 160 (610–1090)
890 ± 180 (620–1250)*
*denotes values significantly different (P
Equine Veterinary Journal ISSN 0425-1644 DOI: 10.1111/evj.12167
Experimental and Basic Research Studies
Ureteropyeloscopic anatomy of the renal pelvis of the horse S. G. PASQUEL, D. AGNEW†, N. NELSON‡, J. M. KRUGER‡, I. SONEA† and H. C. SCHOTT II* Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, USA † Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, USA ‡ Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, USA. *Correspondence email: [email protected]; Received: 20.03.13; Accepted: 02.08.13
Summary Reasons for performing study: Although the equine renal pelvis and terminal recesses have been described post mortem, little information exists about the endoscopic appearance of these structures in the living horse for guiding ureteropyeloscopy. Objectives: To further document the anatomy of the upper urinary collecting system, specifically the renal pelvis and terminal recesses, of the horse. Study design: Descriptive study of cadaver material. Methods: Kidneys were harvested from 10 horses. Magnetic resonance imaging was performed after distension of the renal pelvis with an elastomer casting material, followed by visual inspection of corrosion casts. Transurethral ureteropyeloscopy of the upper urinary tract was performed in 4 horses, followed by histological and immunohistochemical examination of the renal medulla and pelvis of 3 animals. Results: The equine renal pelvis was confirmed to be a funnel-shaped cavity, flattened dorsoventrally in the craniocaudal direction. Multiple papillary ducts (PDs) from the central part of the kidney open along a ∼3 cm long renal crest that protrudes into the renal pelvis, while PDs from each kidney pole open into 2 long (5–10 cm), narrow terminal recesses that terminate near either end of the renal crest. Openings of the terminal recesses narrow at their junction with the renal pelvis and could be visualised during ureteropyeloscopy in all horses. Minor anatomical variation of the renal crest and terminal recess openings was observed. Conclusions: Current endoscopic equipment can be used to visualise the renal pelvis but could not be advanced into the terminal recesses. The findings of this study will help guide future diagnostic and therapeutic ureteropyeloscopy. Keywords: horse; endoscopy; kidney; renal pelvis; terminal recess
Introduction Urethroscopy and cystoscopy have been performed in horses since the 1970s to examine the lower urinary tract [1–5]. However, evaluation of the upper urinary tract has largely been accomplished using indirect imaging techniques, including ultrasonography, i.v. and retrograde contrast pyelography, and nuclear scintigraphy [6–10]. In man, endoscopic examination of the ureter and renal pelvis (ureteropyeloscopy) has become a routine procedure for direct examination of the upper tract in patients with lithiasis, infection, neoplasia or haematuria [11–13]. Using long, flexible endoscopes with small diameters, ureteropyeloscopy is now possible in horses; however, knowledge of normal endoscopic anatomy of the equine upper urinary tract, specifically the renal pelvis, is a prerequisite for accurate diagnostic interpretation. The anatomy of collecting systems of the kidney varies widely across species. Anatomy textbooks describe the equine renal pelvis as a simple funnel-shaped dilation of the proximal ureter [14–18]. Opposite the outflow path of the ureter is a prominent, slightly concave ridge of tissue termed the renal crest [14–17]. Papillary ducts (PDs) from the central part of the kidney open onto the renal crest allowing urine to exit into the pelvis. In addition, 2 terminal recesses extend from the pelvis towards each kidney pole [14–18]. Papillary ducts from nephrons in the poles of the kidney open into these recesses. Illustrations and corrosion casts depict the terminal recesses to be tubular structures emanating from the renal pelvis [14–18] that might be accessible with a small diameter endoscope. The purpose of this study was to further investigate the anatomy of the upper urinary collecting system of the horse, specifically the renal pelvis and terminal recesses. In addition to direct examination of corrosion casts of the renal pelvis, a novel method using 3-dimensional (3D) reconstruction of magnetic resonance imaging (MRI) scans of proximal ureteral and renal pelvic casts was employed. The renal pelvis was also examined directly via ureteropyeloscopy. Finally, kidney sections were examined visually and microscopically and immunohistochemical labelling was performed to further describe the anatomy of the renal pelvis, terminal recesses, renal crest and inner medulla. Equine Veterinary Journal 45, Suppl. 45 (2013) 31–38 © 2013 EVJ Ltd
Materials and methods Horses studied and specimens collected Kidneys were harvested from 10 horses (7 geldings and 3 mares with a mean age of 6 ± 3 [s.d.] years), within 2 h of euthanasia. Horses were weighed (± 2 kg) on a scale and scored for body condition [19] immediately prior to euthanasia. All horses had normal renal function, assessed by production of concentrated urine and normal ultrasonographic appearance of the kidneys, and were subjected to euthanasia for reasons unrelated to this study. None of the horses studied had been administered nephrotoxic medications within the prior 30 days or had any procedure performed that may have affected renal structure or function. Ureteropyeloscopy was performed in 4 additional horses, 2 mares and 2 geldings with a mean age of 14 ± 9 years with normal renal function and normal ultrasonographic appearance of the kidneys. Immediately following ureteropyeloscopy, 3 of these horses (2 geldings and one mare) were subjected to euthanasia and their kidneys removed for sectioning, histology and immunohistochemistry. Both geldings were Thoroughbred racehorses donated due to chronic lameness; thus, nonsteroidal anti-inflammatory drugs had likely been administered to these horses in the prior several months, but neither had documented use of nephrotoxic medications within the preceding 2 weeks. The mare subjected to euthanasia had been receiving phenylbutazone (2.2 mg/kg bwt per os q. 12 h) for the previous 30 days for treatment of arthritis, while the other mare not subjected to euthanasia had no recent history of medication use. The study protocol and all procedures performed were approved by the Animal Care and Use Committee of Michigan State University.
Urethane hybrid elastomer cast preparation The kidneys and ∼15 cm of the proximal ureter were removed, dissected free of fat and other connective tissue, and weighed (± 10 g). Volume of the tissues was determined by water displacement (± 5 ml). After volume determination, a rapidly setting urethane hybrid elastomer (Bioplastic Corosion Polymer)a was infused using a 60 ml syringe and a plastic i.v. fluid
31
Ureteropyeloscopy in normal horses
3 4
S. G. Pasquel et al.
10
2 7
5 1
11
8
6 9
12
Fig 1: Three-dimensional reconstruction of elastomer within a left kidney detailing where measurements were made: 1. length of the cranial terminal recess; 2. length of caudal terminal recess; 3. renal crest length; 4. renal pelvis proximal diameter; 5. renal pelvis middle diameter; 6. renal pelvis distal diameter; 7. diameter of the pelvic end of the cranial terminal recess; 8. diameter of the midpoint of the cranial terminal recess; 9. diameter of the pole end of the cranial terminal recess; 10. diameter of the pelvic end of the caudal terminal recess; 11. diameter of the midpoint of the caudal terminal recess and 12. diameter of the pole end of the cranial terminal recess.
extension line placed into the ureter to fill the proximal ureter, renal pelvis and terminal recesses. All infusions were performed by the same investigator who held the free end of the ureter tightly around the extension line while elastomer was infused. Infusion was continued until the proximal ureter was fully distended, mild distension of the renal pelvis was visibly evident as subtle enlargement of the renal hilus and moderate resistance to further injection was appreciated. The extension line was removed as the ureter was ligated 5–10 cm from the hilus. The degree of pelvic/hilar distension and volume of elastomer infused (35–40 ml in all specimens) were standardised after attempts in 2 pilot horses (also subjected to euthanasia for reasons unrelated to this study) revealed that infusion with a larger volume and greater force resulted in disruption of the pelvis and extension of cast material into the renal parenchyma. After allowing the elastomer to harden for 15–20 min, T2-weighted MRI sequences of both kidneys (0.2 mm slices) were obtained (Magnetom Espree 1.5T)b with the pair of kidneys resting on their ventral surfaces. Two and 3D images of each kidney and the cast material within the renal pelvis and terminal recesses were reconstructed using commercial softwarec (Fig 1). Kidney volume was estimated after computer tracing and elimination of cast material. Additional measurements obtained from reconstructions of the casts included: diameter of the renal pelvis (craniocaudal direction at 3 locations), renal pelvis volume, renal crest length, length of the cranial and caudal terminal recesses, and diameter of the terminal recesses at 3 locations in a dorsal plane (Fig 1). After completion of the MRI scans, the kidneys were frozen for several days and after subsequent thawing, renal parenchyma was gently dissected away from the casts. The casts were then placed in a 1.0 N HNO3 solution until the remaining renal parenchyma could be rinsed-off to allow visual inspection of the casts.
urethra in mares or via the perineal urethrotomy incision in geldings. Once the ureteral orifice was visualised, a flexible guide wire (Weasel Wire, 0.035 in, standard hydrophilic, 150 cm)e was passed through the instrument channel and directed into the ureteral opening and advanced ∼10 cm. The index and middle fingers were used to grasp the end of the endoscope and manually guide it into the ureter. This procedure was easily accomplished in the 2 mares, but was more challenging in the 2 geldings. Consequently, a 1 ml conical plastic pipette tip (BioDot specific fit pipet tip)f was passed over the guide wire and into the distal ureter to dilate the ureteral orifices in the geldings [20]. Ureteral dilation allowed successful passage of the endoscope in 3 of 4 of the remaining ureters but one ureter was unable to be accessed. Further, the perineal urethrotomy incision was extended to ∼10 cm and a partial dorsal sphincterotomy had to be performed in both geldings to allow adequate manual access to the ureteral orifices. After the endoscope had been advanced ∼10 cm into the ureter, the guide wire was removed and isotonic saline was infused (10 ml/min) with a fluid pump through the channel of the endoscope to maintain dilation of the ureter. The endoscope was subsequently advanced without difficulty a further 50–60 cm to the renal pelvis, which was then explored. In 3 horses, phenol red (P353)g was administered (1 mg/kg bwt i.v.) to facilitate detection of urine excretion from PDs along the renal crest and from the openings of the cranial and caudal terminal recesses. After ureteropyeloscopy, the kidneys of the 3 horses subjected to euthanasia were collected for gross, histological and immunohistochemical examination.
Gross anatomy, histology and immunohistochemistry Within 2 h of euthanasia, harvested kidneys were infused with 60 ml of 10% formalin in a retrograde fashion through the ureter, in a manner similar to that used for elastomer infusion and the ureter ligated allowing the renal pelvis and terminal recesses to be fixed in a distended state. The kidneys were then submerged in 10% formalin. After 3 days of fixation, the kidneys were sectioned (5–10 mm slices) along a sagittal axis (Fig 2) and each section photographed. Subsections (0.5 cm thick x 2 cm long x 1.5 cm wide) of medulla, containing the terminal recesses or renal pelvis, were placed in tissue cassettes, sectioned at 4–5 μm and stained with haematoxylin and eosin. Additional 4–5 μm sections, adjacent to those examined by routine histology, were labelled with a murine monoclonal antibody against smooth muscle actin (αSMA), after being deparaffinised in xylene and hydrated. Heat-induced epitope retrieval was performed and endogenous peroxidase was blocked using a 3% hydrogen peroxide/methanol bath. After incubation with normal goat serum to limit nonspecific protein binding, sections were incubated with avidin and biotin for 15 min. Primary antibody slides were incubated for 60 min with a murine monoclonal
9
Lateral 8
10
7 6
11 5
Ureteropyeloscopy
Cranial
32
4 Caudal
Horses were restrained standing in stocks and sedated with detomidine hydrochloride (0.02 mg/kg bwt i.v.). An i.v. catheter was aseptically placed into the jugular vein. The tail was wrapped and pulled to the side, faeces were manually evacuated from the rectum and the perineum prepared as for cystoscopy (mares) or surgery (geldings). A urethral catheter was passed into the bladder of the geldings and a 7 cm vertical perineal urethrotomy was performed. In both sexes, 20 ml of a 2% lidocaine HCl solution were infused into the bladder through a bladder catheter for topical anaesthesia after emptying the bladder of urine. The urethral sphincter was subsequently manually dilated until the index and middle fingers of a hand within a sterile glove could be easily passed into the bladder and the ureteral orifices could be palpated [20]. The endoscope (GIF-N180 SlimSIGHT ultra-slim video gastroscope)d (110 cm working length, 4.9 mm outer diameter, 2.0 mm instrument channel, 120° field of view via angulation of 220/120°) was then passed into the bladder via the
12 3
13
2 14
1 15 16 Medial
Fig 2: Diagram of a left kidney showing the pattern used to section the kidney for gross anatomical and histological examination. Equine Veterinary Journal 45, Suppl. 45 (2013) 31–38 © 2013 EVJ Ltd
Ureteropyeloscopy in normal horses
S. G. Pasquel et al.
TABLE 1: Mean ± s.d. values (range) for kidney weight, kidney volume measured by water displacement and kidney volume estimated from MRI reconstructions in 10 horses Measurement
Left kidney
Right kidney
Weight (g) Volume (water displacement, cm3) Volume (MRI, cm3)
960 ± 130 (760–1200) 810 ± 140 (610–1060)
990 ± 180 (740–1400) 880 ± 180 (600–1240)*
820 ± 160 (610–1090)
890 ± 180 (620–1250)*
*denotes values significantly different (P
