Journal of Feline Medicine and Surgery http://jfm.sagepub.com/
Cystourethroscopy in the cat: What do you need? When do you need it? How do you do it? Allyson Berent Journal of Feline Medicine and Surgery 2014 16: 34 DOI: 10.1177/1098612X13516570 The online version of this article can be found at: http://jfm.sagepub.com/content/16/1/34
Disclaimer The Journal of Feline Medicine and Surgery is an international journal and authors may discuss products and formulations that are not available or licensed in the individual reader's own country. Furthermore, drugs may be mentioned that are licensed for human use, and not for veterinary use. Readers need to bear this in mind and be aware of the prescribing laws pertaining to their own country. Likewise, in relation to advertising material, it is the responsibility of the reader to check that the product is authorised for use in their own country. The authors, editors, owners and publishers do not accept any responsibility for any loss or damage arising from actions or decisions based on information contained in this publication; ultimate responsibility for the treatment of animals and interpretation of published materials lies with the veterinary practitioner. The opinions expressed are those of the authors and the inclusion in this publication of material relating to a particular product, method or technique does not amount to an endorsement of its value or quality, or the claims made by its manufacturer.
Published by: International Society of Feline Medicine
American Association of Feline Practitioners
and http://www.sagepublications.com
Additional services and information for Journal of Feline Medicine and Surgery can be found at: Email Alerts: http://jfm.sagepub.com/cgi/alerts Subscriptions: http://jfm.sagepub.com/subscriptions Reprints: http://www.sagepub.com/journalsReprints.nav Permissions: http://www.sagepub.com/journalsPermissions.nav
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Journal of Feline Medicine and Surgery (2014) 16, 34–41
CLINICAL REVIEW
CYSTOURETHROSCOPY IN THE CAT What do you need? When do you need it? How do you do it? Allyson Berent
Practical relevance: Diagnostic and therapeutic cystourethroscopy has become very popular in the diagnosis and treatment of canine lower and upper urinary tract disease in the past 5–7 years. As expertise is expanding, the use of similar techniques in feline patients is growing. Outline: This is a brief overview of the indications, equipment needed and procedure for performing cystourethroscopy in feline patients. The principal focus is normal feline lower urinary tract anatomy. Some examples of abnormalities that might be seen are also provided, and therapeutic cystourethroscopy is touched upon.
Indications for cystourethroscopy
Signs of lower urinary tract disease in feline patients are among the most common presenting complaints by owners attending small animal veterinary practice.1,2 These signs include dysuria, hematuria, pollakiuria, nocturia, periuria, stranguria, vulvar or prepucial discharge and incontinence. Other indications for endoscopic evaluation are abnormal findings on ultrasound examination or contrast studies, recurrent urinary tract infections and the presence of urinary calculi. Imaging of the vestibule, vagina, urethra, bladder and ureterovesicular junctions can be accomplished with diagnostic cystourethroscopy to confirm normal anatomy and/or the presence of tumors, strictures, stones, foreign bodies, bladder wall lesions and upper tract renal/ ureteral bleeding from the ureterovesicular junction, among other abnormalities.3,4 In addition to the diagnostic utility of cystourethroscopy, numerous therapeutic interventions can be performed simultaneously, including stone removal (basketing, voiding, laser lithotripsy), cystoscopic-guided laser ablation of ectopic ureters, polyp resection, stricture balloon dilation or stenting, malignant obstruction biopsy and/or stenting, injection of bulking agents for incontinence, cauterization for bleeding, and endoscopic retrograde ureteral stenting for ureteral obstructions.3–16
Equipment
New techniques on the horizon: ‘endourology’ An accompanying article on pages 51–65 of this Special Issue discusses new interventional treatments for urinary tract disease in veterinary patients.
Various flexible, rigid and semi-rigid endoscopes can be used for cystourethroscopy in cats (Figure 1): < A rigid cystoscope (1.9 mm 30° endoscope with a 3 French [Fr] working channel) is most commonly used in female cats for vaginal, urethral, bladder and/or ureteral access. For male cats, rigid cystourethroscopy can be performed from an antegrade approach (advancing through the bladder apex and down the urethra), but does not allow imaging of the penile urethra. < A flexible ureteroscope can be used for urethral evaluation when the rigid scope is too large (small female cats), or when antegrade urethroscopy is needed for the more distal aspect of the pelvic urethra. < A semi-rigid cystoscope for male cats is available, though the image quality obtained is relatively poor compared with a rigid scope. Allyson Berent DVM Dipl ACVIM The Animal Medical Center, New York, USA Email: [email protected]
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DOI: 10.1177/1098612X13516570 © ISFM and AAFP 2014
R E V I E W / Cystourethroscopy
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A newer prototype is under way that is 4.5 Fr in diameter and has a 0.018" (0.46 mm) working channel, making irrigation and wire intervention possible. Room set-up and use of good quality monitors are both important factors when performing cystourethroscopy in order that everything can be visualized appropriately. The monitor should ideally be positioned directly in line with the scope so that the operator is always looking forwards (Figure 2a,b). If this is not possible, the monitor can also be positioned to the left of the operator (Figure 2c,d). Figure 1 Equipment needed for cystourethroscopy, including (a) light box, (b) light guide cable, (c) camera and camera box and (d) various cystoscopes. The five cystoscopes displayed are: (1) semi-rigid male/feline endoscope, (2) 1.9 mm 30° rigid cystoscope, (3) 2.7 mm 30° rigid cystoscope, (4) 4 mm 30° rigid cystoscope and (5) 2.5 mm flexible fiberoptic cystoureteroscope
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Figure 2 Room set-up for routine cystourethroscopy. (a,b) Clinicians at the Animal Medical Center have the advantage of a high-tech set-up enabling them to face forwards during the procedure. While in practice this is seldom possible (c,d), good visualization remains key and is achievable. Images (c) and (d) courtesy of Christiane Stengel, Tierklinik Hofheim, Germany
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R E V I E W / Cystourethroscopy
fpr Anatomic considerations Female feline patients Female cats have a vestibule which, when entered, leads to two openings – the dorsal vaginal opening and the more ventral slit of the urethral opening (Figures 3 and 4).1,2 Cystourethroscopy in the author’s practice is performed in dorsal recumbency, so the vagina is typically seen towards the bottom of the field of view and the urethral opening towards the top. The urethra in a female cat is narrow, thin and relatively long compared with its canine counterpart.1,2 The thinwalled feline urinary bladder is in the peritoneal cavity. The ureterovesicular junctions are typically on the ureteral papilla which sits just caudal to the bladder neck at the urethrovesicular junction, in the proximal urethra.
Figure 3 In the female cat the vagina sits dorsal to the urethral opening and the urethra is long with a slight bend to it. The ureters enter the proximal urethra after traversing intramurally through the bladder neck Figure 4 The vestibule of a female cat seen during dorsal cystourethroscopy. The vagina is a small round opening (black arrow) and the urethra is a longitudinal slit (white arrow) above the vagina. Dorsal is towards the bottom of the image; ventral towards the top
An understanding of normal anatomy is important to perform urethrocystography safely and effectively.
Male feline patients Male cats have a very narrow (1–2 mm) distal urethral lumen, the penile urethra (Figure 5), which sits in a prepuce. The penile urethra dilates from 1–2 mm to 3–6 mm in diameter at the ischium, becoming the pelvic urethra. Male cats have a bulbo urethrogland at the ischium and a prostate gland in the proximal pelvic urethra. The bladder, ureteral and pelvic urethral anatomy is similar to that of the female cat.
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Figure 5 The male cat has a very narrow penile urethra that is ventral and caudal to the pelvic urethra. At the ischium is the bulbourethral gland where the urethra takes a right angle and then runs parallel within the pelvis until it reaches the bladder. A small prostate gland sits around the proximal urethral lumen; the ureteral openings are also located in the proximal urethra
R E V I E W / Cystourethroscopy
The feline bladder can typically hold between 5 and 25 ml/kg of fluid. Care must be taken to avoid overdistension.
a Figure 6 (a) A 2.7 mm 30° rigid cystoscope. Yellow arrow indicates the eyepiece that attaches to the camera; red arrow indicates the working channel of the endoscope; black and white arrows indicate the ports for ingress or egress of irrigation fluids; blue arrow indicates the adaptor for the light guide cable; purple arrow indicates the end of the endoscope, demonstrating the 30° angle. (b) The same endoscope attached to the camera head (yellow arrow), showing the fluid line for irrigation (black arrow), working channel cap (red arrow) and light guide cable (blue arrow)
b
A fluid bag of warm sterile saline (1 l) should be hanging. The author prefers to use a pressure bag to maintain good fluid flow through the narrow working channel of the endoscope, and typically warms the fluid in a fluid warmer. Care must be taken to ensure the bladder is never overdistended, as this could result in excessive bleeding and, potentially, bladder rupture. The feline bladder can typically hold between 5 and 25 ml/kg of fluid and care must be taken to ensure that the bladder is not overfilled.
The cystoscope typically has three ports: a working channel, an ingress and an egress port. Fluids should be attached to one port for ingress, and an extension set to one port for egress. The working channel port needs a good quality cap to prevent fluids from running out of the channel during interventions requiring the channel to be open (Figure 6). An eyepiece attaches to the camera head and the rigid scope has a 30° angle to facilitate visualization at different angles throughout the urethra and bladder (Figure 6). Additional equipment needed for therapeutic cystourethroscopy is described in more detail in the accompanying article in this Special Issue series.
Cystourethroscopy procedure
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Figure 7 Endoscopic images of a female cat during urethroscopy in dorsal recumbency. (a) The distal urethra is very narrow and often more pale than the mid-proximal urethra. The folds of the urethral tissue are seen and small stones are visualized in this image. (b) The pelvic urethra has a dorsal bulge of tissue (bottom) that extends as far as the ureteral papillae. Note the parallel folds of urethral tissue ventrally. Note also that the lumen of the urethra is maintained towards the bottom of the screen to retain the 30° angle, keeping the endoscope straight in the urethral lumen to prevent urethral trauma. (c) The proximal urethra, with a view of the urethrovesicular junction/trigone. (d) The ureteral papilla at the urethrovesicular junction prior to entering the urinary bladder
For both male and female cats the author positions the patient in dorsal recumbency with the perineum aligned with the end of the table, and the tail hanging straight down. Placing the patient in a small trough will help to keep it upright and secure. The entire area of the vulva/prepuce and perineum is clipped and aseptically prepared. The vulva or prepuce is flushed with dilute chlorhexidine solution. For male and smaller female cats the abdomen is clipped and scrubbed as well, in case antegrade cystourethroscopy is needed. Ideally, the patient is then covered with a sterile patient drape, with a hole made in the area of the vulva/prepuce, using towel clamps to hold it in place. The author always gowns and gloves for the procedure. Female cats Using a 1.9 mm 30° rigid cystoscope the vulva is entered and the endoscope is aimed down towards the vestibule (Figure 4). Once the urethral opening, which typically appears as a
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R E V I E W / Cystourethroscopy
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Figure 8 Endoscopic images of a female cat during dorsal cystourethroscopy showing (a) the ureteral papilla (arrow) in the proximal urethra. (b) The ureterovesicular junction is seen as a small hole on the top of the papilla (arrow). (c) Close-up image of the ureteral opening (arrow)
vertical slit, is visualized the vaginal opening is inspected but the vagina is not entered, as this is considered more contaminated than the urethra. The endoscope is then gently passed into the urethral lumen, being careful to avoid overfilling the urethra and bladder with aggressive fluid irrigation but using enough irrigation to allow the urethra to distend for safe endoscope passage. If the endoscope feels tight or is hitting resistance the procedure a should be aborted, as the smallest rigid endoscope can be too large for smaller female cats. In such cases, exchanging for a flexible ureteroscope or semi-rigid male cat cystoscope should be considered. If this is not possible then antegrade cystourethroscopy can be performed (see later). Once the urethra is entered care should be taken to maintain the lumen of the urethra at the bottom of the screen to keep the endoscope straight and the 30° angle of the cystoscope aiming up b (Figure 7). The most distal aspect of the urethra is often the most narrow and is lighter in color than the proximal urethra. As the mid-urethra is entered, a dorsal ridge will be seen at the bottom of the screen (Figure 7b,c); this is a normal feature in cats. At the most proximal aspect of this ridge are the ureteral papillae (Figure 7d) that sit in the proximal urethra. Each ureteral opening (ureterovesicular junction) appears as a slit on the top of each papilla (Figure 8).
On entering the bladder, the irrigation fluid should be turned off immediately and the bladder drained through the egress port. The entire bladder from apex to trigone should be carefully evaluated for vascularity (Figure 9), thickness, nodules, smoothness, urachus and size. Finally the endoscope should be turned with the 30° angle facing down (towards the floor), keeping the camera in the same position, so that the dorsal (dependent) aspect of the bladder and urethra can be carefully visualized. This allows the ureteral openings to be investigated (Figure 8). The ureteral openings sit in the proximal urethra, just caudal to the bladder neck; the openings appear as a small slit on each ureteral papilla. Urine should be visualized coming from each orifice to be sure there is no blood and that each ureter is patent. If stones are present they may be seen on the bladder floor as they will fall to the dependent portion of the bladder (Figure 10). Figure 10 Bladder stones on the dependent surface of the urinary bladder seen during cystourethroscopy. Note the pale bladder wall
Figure 9 Cystoscopic images of the bladder wall in two cats. (a) Normal vasculature of the bladder wall. (b) Thickened pale bladder wall with minimal vasculature seen in a cat with chronic cystitis and stone disease
The normal feline ureteral openings are found in the proximal urethra, rather than the bladder, and thus these are not ectopic.
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R E V I E W / Cystourethroscopy
fpr Antegrade cystourethroscopy
Figure 11 Schematic of the PCCL procedure (discussed further in the accompanying article)
Antegrade cystourethroscopy is a procedure that is most commonly used in the author’s practice for the removal of bladder stones in male and female cats (percutaneous cystolithotomy, PCCL), and for diagnostic imaging in small female cats or male cats in which an intervention might be needed (biopsy, stent placement, etc). This is performed through a 1 cm skin incision over the apex of the urinary bladder. Through this small incision, on the ventral midline, the urinary bladder is isolated and stay sutures are used to secure it to the body wall (Figure 11). Using a screw trocar with a diaphragm (Figure 12), a small stab incision is made into the apex to maintain a closed system for bladder distension during access for the rigid endoscope. Then, from an antegrade direction, the urinary bladder, proximal ureterovesicular junctions and proximal urethra can be carefully evaluated (Figure 13). Once cystourethroscopy is complete, the hole for the trocar is closed using Figure 12 Screw trocar absorbable suture material and the used to maintain irrigation and distension abdominal wall is closed in three layers during antegrade routinely. This is considered an outcystourethroscopy (PCCL procedure) patient procedure.
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Figure 13 Antegrade cystourethroscopy (PCCL procedure) in a male cat with bladder stones. (a) Normal bladder wall. (b) Stones (calcium oxalate) on the dependent surface of the bladder wall. (c) Proximal urethra showing the ureteral papilla and the slits of the ureterovesicular junction. (d) Midurethral lumen viewed with the rigid cystoscope
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R E V I E W / Cystourethroscopy
Abnormalities
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Figure 14 Urethroscopic images of a male cat during semi-rigid cystourethroscopy. The image quality is not as good as that provided by a rigid endoscope. This is a 0° endoscope so the image does not need to be angled and the lumen should remain in the center of the screen. (a) Distal penile urethra, (b) mid-pelvic urethra, (c) proximal pelvic urethra and (d) ureteral papilla in the proximal urethra
Male cats In male cats cystourethroscopy can either be performed in a retrograde manner using a semi-rigid endoscope or in an antegrade manner using a 1.9 mm rigid cystoscope (see page 39). The semi-rigid scope allows visualization of the penile urethra but the image quality and ability to irrigate, biopsy or perform therapeutic interventions is limited due to the absence of, or only a very small, working channel (Figure 14).
The most common abnormalities seen in the urethra in the author’s experience are strictures, stones and tumors (Figure 15). Interestingly, strictures are most commonly seen by the author in the pelvic urethra after trauma or congenitally in the very proximal urethra at the ureterovesicular junction. Ectopic ureteral openings are not commonly seen in cats and the operator should realize that the normal feline ureteral openings are found in the proximal urethra, rather than the bladder, and thus these are not ectopic. In the urinary bladder, tumors, stones, polyps and glomerulations, associated with feline idiopathic cystitis, can be seen endoscopically. A diagnosis can be obtained using various instruments/biopsy methods (cup biopsy forceps, basket, snare) (Figure 16). Therapeutically, wires, catheters, snares, lasers and stents can be employed (Figure 17), and this is expanded on in the accompanying article.
Figure 15 Endoscopic biopsy cup forceps being used to
Figure 16 Bladder stone being retrieved with a stone
sample a bladder tumor
retrieval basket during PCCL in a male cat
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Figure 17 Urethral abnormalities seen during urethroscopy in three different female cats. (a) Congenital urethral stricture located between the ureteral openings and the bladder trigone. Note that the ureteral openings (black arrow) are on the distal side of the stricture. The narrow urethral opening is shown with a red arrow. (b) Bladder stones within the urethral lumen. (c) Proximal urethral transitional cell carcinoma causing an obstruction
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R E V I E W / Cystourethroscopy
KEY POINTS < Cystourethroscopy is a valuable diagnostic tool in the evaluation of feline patients with lower urinary tract disease.
< Care should be taken as the feline urethra and bladder are very fragile and can be easily traumatized during cystourethroscopy.
6 7
< Therapeutic cystourethroscopy is being more commonly employed in feline patients for the treatment of stone disease, incontinence, neoplasia and ureteral obstructions/disease.
< To perform this technique safely and effectively suitable
training should be undertaken to ensure appropriate technique is used and the best instruments are available.
< Knowledge of the anatomical normals is vital in the diagnosis of disease.
8 9 10
Funding
The author received no specific grant from any funding agency in the public, commercial or not-forprofit sectors for the preparation of this article.
Conflict of interest
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The author is an advisor for Infiniti Medical and Norfolk Vet Products.
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References
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McCarthy T. Cystourethroscopy and biopsy of the feline lower urinary tract. Vet Clin North Am Small Anim Pract 1996; 26: 463–482. Chew DJ, Buffington T, Kendall MS, Osborn SD and Woodsworth BE. Urethroscopy, cystoscopy, and biopsy of the feline lower urinary tract. Vet Clin North Am Small Anim Pract 1996; 26: 441–462. Messer JS, Chew DJ and McLoughlin MA. Cystoscopy: techniques and clinical applications. Clin Tech Small Anim Pract 2005; 20: 52–64. Cannizzo KL, McLoughlin MA, Chew DJ and DiBartola SP. Uroendoscopy. Evaluation of the lower urinary tract. Vet Clin North Am Small Anim Pract 2001; 31: 789–807. Berent A and Weisse C. Interventional radiology and endourology. In: Bonagura JD (ed).
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Current veterinary therapy XV. Elsevier. In Press 2014. Berent A. Urinary stenting in dogs and cats. In: Polzin J and Bartges D (eds). Nephrology and urology of small animals. Wiley Blackwell, 2011, pp 329–339. Berent A. Urologic interventional techniques in the feline patient. In: August JR (ed). Consultations in feline internal medicine. Vol 6. St Louis: Saunders, Elsevier, 2009, pp 516–532. Weisse C and Berent A. Potential applications of interventional radiology in veterinary medicine. J Am Vet Med Assoc 2008; 233: 1564–1574. Berent A, Weisse C and Bagley D. Feline ureteral stenting for the treatment of benign ureteral obstruction in cats: 2006–2012. J Am Vet Med Assoc. In Press 2014. Horowitz C, Berent A, Weisse C, Langston C, and Bagley D. Predictors of outcome for cats with ureteral obstructions after interventional management using ureteral stents or a subcutaneous ureteral bypass device. J Feline Med Surg 2013; 15: 1052–1062. Defarges A, Berent A and Dunn M. New alternatives for minimally invasive management of uroliths: ureteroliths. Compend Contin Educ Pract Vet 2013; 35(3): E4. Defarges A, Dunn M and Berent A. Lithotripsy and minimally invasive removal of lower urinary tract stones: lower urinary tract uroliths. Compend Contin Educ Pract Vet 2013; 35(1): E1. Holmes ES, Weisse C and Berent A. Use of fluoroscopically guided percutaneous antegrade urethral catheterization for the treatment of urethral obstruction in male cats: 9 cases (2000–2009). J Am Vet Med Assoc 2012; 241: 603–607. Zaid MS, Berent AC, Weisse C and Caceres A. Feline ureteral strictures: 10 cases (2007–2009). J Vet Intern Med 2011; 25: 222–229. Runge J, Berent A, Weisse C and Mayhew P. Transvesicular percutaneous cystolithotomy for the retrieval of cystic and urethral calculi in dogs and cats: 27 cases (2006–2008). J Am Vet Med Assoc 2011; 239: 344–349. Berent A. Ureteral obstructions in dogs and cats: a review of traditional and new interventional diagnostic and therapeutic options. J Vet Emerg Crit Care 2011; 21: 86–103.
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Cystourethroscopy in the cat: What do you need? When do you need it? How do you do it? Allyson Berent Journal of Feline Medicine and Surgery 2014 16: 34 DOI: 10.1177/1098612X13516570 The online version of this article can be found at: http://jfm.sagepub.com/content/16/1/34
Disclaimer The Journal of Feline Medicine and Surgery is an international journal and authors may discuss products and formulations that are not available or licensed in the individual reader's own country. Furthermore, drugs may be mentioned that are licensed for human use, and not for veterinary use. Readers need to bear this in mind and be aware of the prescribing laws pertaining to their own country. Likewise, in relation to advertising material, it is the responsibility of the reader to check that the product is authorised for use in their own country. The authors, editors, owners and publishers do not accept any responsibility for any loss or damage arising from actions or decisions based on information contained in this publication; ultimate responsibility for the treatment of animals and interpretation of published materials lies with the veterinary practitioner. The opinions expressed are those of the authors and the inclusion in this publication of material relating to a particular product, method or technique does not amount to an endorsement of its value or quality, or the claims made by its manufacturer.
Published by: International Society of Feline Medicine
American Association of Feline Practitioners
and http://www.sagepublications.com
Additional services and information for Journal of Feline Medicine and Surgery can be found at: Email Alerts: http://jfm.sagepub.com/cgi/alerts Subscriptions: http://jfm.sagepub.com/subscriptions Reprints: http://www.sagepub.com/journalsReprints.nav Permissions: http://www.sagepub.com/journalsPermissions.nav
>> Version of Record - Dec 20, 2013 What is This? Downloaded from jfm.sagepub.com at TEXAS SOUTHERN UNIVERSITY on November 28, 2014
Journal of Feline Medicine and Surgery (2014) 16, 34–41
CLINICAL REVIEW
CYSTOURETHROSCOPY IN THE CAT What do you need? When do you need it? How do you do it? Allyson Berent
Practical relevance: Diagnostic and therapeutic cystourethroscopy has become very popular in the diagnosis and treatment of canine lower and upper urinary tract disease in the past 5–7 years. As expertise is expanding, the use of similar techniques in feline patients is growing. Outline: This is a brief overview of the indications, equipment needed and procedure for performing cystourethroscopy in feline patients. The principal focus is normal feline lower urinary tract anatomy. Some examples of abnormalities that might be seen are also provided, and therapeutic cystourethroscopy is touched upon.
Indications for cystourethroscopy
Signs of lower urinary tract disease in feline patients are among the most common presenting complaints by owners attending small animal veterinary practice.1,2 These signs include dysuria, hematuria, pollakiuria, nocturia, periuria, stranguria, vulvar or prepucial discharge and incontinence. Other indications for endoscopic evaluation are abnormal findings on ultrasound examination or contrast studies, recurrent urinary tract infections and the presence of urinary calculi. Imaging of the vestibule, vagina, urethra, bladder and ureterovesicular junctions can be accomplished with diagnostic cystourethroscopy to confirm normal anatomy and/or the presence of tumors, strictures, stones, foreign bodies, bladder wall lesions and upper tract renal/ ureteral bleeding from the ureterovesicular junction, among other abnormalities.3,4 In addition to the diagnostic utility of cystourethroscopy, numerous therapeutic interventions can be performed simultaneously, including stone removal (basketing, voiding, laser lithotripsy), cystoscopic-guided laser ablation of ectopic ureters, polyp resection, stricture balloon dilation or stenting, malignant obstruction biopsy and/or stenting, injection of bulking agents for incontinence, cauterization for bleeding, and endoscopic retrograde ureteral stenting for ureteral obstructions.3–16
Equipment
New techniques on the horizon: ‘endourology’ An accompanying article on pages 51–65 of this Special Issue discusses new interventional treatments for urinary tract disease in veterinary patients.
Various flexible, rigid and semi-rigid endoscopes can be used for cystourethroscopy in cats (Figure 1): < A rigid cystoscope (1.9 mm 30° endoscope with a 3 French [Fr] working channel) is most commonly used in female cats for vaginal, urethral, bladder and/or ureteral access. For male cats, rigid cystourethroscopy can be performed from an antegrade approach (advancing through the bladder apex and down the urethra), but does not allow imaging of the penile urethra. < A flexible ureteroscope can be used for urethral evaluation when the rigid scope is too large (small female cats), or when antegrade urethroscopy is needed for the more distal aspect of the pelvic urethra. < A semi-rigid cystoscope for male cats is available, though the image quality obtained is relatively poor compared with a rigid scope. Allyson Berent DVM Dipl ACVIM The Animal Medical Center, New York, USA Email: [email protected]
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DOI: 10.1177/1098612X13516570 © ISFM and AAFP 2014
R E V I E W / Cystourethroscopy
1
2
3
4
5
a
b
c
A newer prototype is under way that is 4.5 Fr in diameter and has a 0.018" (0.46 mm) working channel, making irrigation and wire intervention possible. Room set-up and use of good quality monitors are both important factors when performing cystourethroscopy in order that everything can be visualized appropriately. The monitor should ideally be positioned directly in line with the scope so that the operator is always looking forwards (Figure 2a,b). If this is not possible, the monitor can also be positioned to the left of the operator (Figure 2c,d). Figure 1 Equipment needed for cystourethroscopy, including (a) light box, (b) light guide cable, (c) camera and camera box and (d) various cystoscopes. The five cystoscopes displayed are: (1) semi-rigid male/feline endoscope, (2) 1.9 mm 30° rigid cystoscope, (3) 2.7 mm 30° rigid cystoscope, (4) 4 mm 30° rigid cystoscope and (5) 2.5 mm flexible fiberoptic cystoureteroscope
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b
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Figure 2 Room set-up for routine cystourethroscopy. (a,b) Clinicians at the Animal Medical Center have the advantage of a high-tech set-up enabling them to face forwards during the procedure. While in practice this is seldom possible (c,d), good visualization remains key and is achievable. Images (c) and (d) courtesy of Christiane Stengel, Tierklinik Hofheim, Germany
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R E V I E W / Cystourethroscopy
fpr Anatomic considerations Female feline patients Female cats have a vestibule which, when entered, leads to two openings – the dorsal vaginal opening and the more ventral slit of the urethral opening (Figures 3 and 4).1,2 Cystourethroscopy in the author’s practice is performed in dorsal recumbency, so the vagina is typically seen towards the bottom of the field of view and the urethral opening towards the top. The urethra in a female cat is narrow, thin and relatively long compared with its canine counterpart.1,2 The thinwalled feline urinary bladder is in the peritoneal cavity. The ureterovesicular junctions are typically on the ureteral papilla which sits just caudal to the bladder neck at the urethrovesicular junction, in the proximal urethra.
Figure 3 In the female cat the vagina sits dorsal to the urethral opening and the urethra is long with a slight bend to it. The ureters enter the proximal urethra after traversing intramurally through the bladder neck Figure 4 The vestibule of a female cat seen during dorsal cystourethroscopy. The vagina is a small round opening (black arrow) and the urethra is a longitudinal slit (white arrow) above the vagina. Dorsal is towards the bottom of the image; ventral towards the top
An understanding of normal anatomy is important to perform urethrocystography safely and effectively.
Male feline patients Male cats have a very narrow (1–2 mm) distal urethral lumen, the penile urethra (Figure 5), which sits in a prepuce. The penile urethra dilates from 1–2 mm to 3–6 mm in diameter at the ischium, becoming the pelvic urethra. Male cats have a bulbo urethrogland at the ischium and a prostate gland in the proximal pelvic urethra. The bladder, ureteral and pelvic urethral anatomy is similar to that of the female cat.
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Figure 5 The male cat has a very narrow penile urethra that is ventral and caudal to the pelvic urethra. At the ischium is the bulbourethral gland where the urethra takes a right angle and then runs parallel within the pelvis until it reaches the bladder. A small prostate gland sits around the proximal urethral lumen; the ureteral openings are also located in the proximal urethra
R E V I E W / Cystourethroscopy
The feline bladder can typically hold between 5 and 25 ml/kg of fluid. Care must be taken to avoid overdistension.
a Figure 6 (a) A 2.7 mm 30° rigid cystoscope. Yellow arrow indicates the eyepiece that attaches to the camera; red arrow indicates the working channel of the endoscope; black and white arrows indicate the ports for ingress or egress of irrigation fluids; blue arrow indicates the adaptor for the light guide cable; purple arrow indicates the end of the endoscope, demonstrating the 30° angle. (b) The same endoscope attached to the camera head (yellow arrow), showing the fluid line for irrigation (black arrow), working channel cap (red arrow) and light guide cable (blue arrow)
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A fluid bag of warm sterile saline (1 l) should be hanging. The author prefers to use a pressure bag to maintain good fluid flow through the narrow working channel of the endoscope, and typically warms the fluid in a fluid warmer. Care must be taken to ensure the bladder is never overdistended, as this could result in excessive bleeding and, potentially, bladder rupture. The feline bladder can typically hold between 5 and 25 ml/kg of fluid and care must be taken to ensure that the bladder is not overfilled.
The cystoscope typically has three ports: a working channel, an ingress and an egress port. Fluids should be attached to one port for ingress, and an extension set to one port for egress. The working channel port needs a good quality cap to prevent fluids from running out of the channel during interventions requiring the channel to be open (Figure 6). An eyepiece attaches to the camera head and the rigid scope has a 30° angle to facilitate visualization at different angles throughout the urethra and bladder (Figure 6). Additional equipment needed for therapeutic cystourethroscopy is described in more detail in the accompanying article in this Special Issue series.
Cystourethroscopy procedure
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Figure 7 Endoscopic images of a female cat during urethroscopy in dorsal recumbency. (a) The distal urethra is very narrow and often more pale than the mid-proximal urethra. The folds of the urethral tissue are seen and small stones are visualized in this image. (b) The pelvic urethra has a dorsal bulge of tissue (bottom) that extends as far as the ureteral papillae. Note the parallel folds of urethral tissue ventrally. Note also that the lumen of the urethra is maintained towards the bottom of the screen to retain the 30° angle, keeping the endoscope straight in the urethral lumen to prevent urethral trauma. (c) The proximal urethra, with a view of the urethrovesicular junction/trigone. (d) The ureteral papilla at the urethrovesicular junction prior to entering the urinary bladder
For both male and female cats the author positions the patient in dorsal recumbency with the perineum aligned with the end of the table, and the tail hanging straight down. Placing the patient in a small trough will help to keep it upright and secure. The entire area of the vulva/prepuce and perineum is clipped and aseptically prepared. The vulva or prepuce is flushed with dilute chlorhexidine solution. For male and smaller female cats the abdomen is clipped and scrubbed as well, in case antegrade cystourethroscopy is needed. Ideally, the patient is then covered with a sterile patient drape, with a hole made in the area of the vulva/prepuce, using towel clamps to hold it in place. The author always gowns and gloves for the procedure. Female cats Using a 1.9 mm 30° rigid cystoscope the vulva is entered and the endoscope is aimed down towards the vestibule (Figure 4). Once the urethral opening, which typically appears as a
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R E V I E W / Cystourethroscopy
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Figure 8 Endoscopic images of a female cat during dorsal cystourethroscopy showing (a) the ureteral papilla (arrow) in the proximal urethra. (b) The ureterovesicular junction is seen as a small hole on the top of the papilla (arrow). (c) Close-up image of the ureteral opening (arrow)
vertical slit, is visualized the vaginal opening is inspected but the vagina is not entered, as this is considered more contaminated than the urethra. The endoscope is then gently passed into the urethral lumen, being careful to avoid overfilling the urethra and bladder with aggressive fluid irrigation but using enough irrigation to allow the urethra to distend for safe endoscope passage. If the endoscope feels tight or is hitting resistance the procedure a should be aborted, as the smallest rigid endoscope can be too large for smaller female cats. In such cases, exchanging for a flexible ureteroscope or semi-rigid male cat cystoscope should be considered. If this is not possible then antegrade cystourethroscopy can be performed (see later). Once the urethra is entered care should be taken to maintain the lumen of the urethra at the bottom of the screen to keep the endoscope straight and the 30° angle of the cystoscope aiming up b (Figure 7). The most distal aspect of the urethra is often the most narrow and is lighter in color than the proximal urethra. As the mid-urethra is entered, a dorsal ridge will be seen at the bottom of the screen (Figure 7b,c); this is a normal feature in cats. At the most proximal aspect of this ridge are the ureteral papillae (Figure 7d) that sit in the proximal urethra. Each ureteral opening (ureterovesicular junction) appears as a slit on the top of each papilla (Figure 8).
On entering the bladder, the irrigation fluid should be turned off immediately and the bladder drained through the egress port. The entire bladder from apex to trigone should be carefully evaluated for vascularity (Figure 9), thickness, nodules, smoothness, urachus and size. Finally the endoscope should be turned with the 30° angle facing down (towards the floor), keeping the camera in the same position, so that the dorsal (dependent) aspect of the bladder and urethra can be carefully visualized. This allows the ureteral openings to be investigated (Figure 8). The ureteral openings sit in the proximal urethra, just caudal to the bladder neck; the openings appear as a small slit on each ureteral papilla. Urine should be visualized coming from each orifice to be sure there is no blood and that each ureter is patent. If stones are present they may be seen on the bladder floor as they will fall to the dependent portion of the bladder (Figure 10). Figure 10 Bladder stones on the dependent surface of the urinary bladder seen during cystourethroscopy. Note the pale bladder wall
Figure 9 Cystoscopic images of the bladder wall in two cats. (a) Normal vasculature of the bladder wall. (b) Thickened pale bladder wall with minimal vasculature seen in a cat with chronic cystitis and stone disease
The normal feline ureteral openings are found in the proximal urethra, rather than the bladder, and thus these are not ectopic.
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R E V I E W / Cystourethroscopy
fpr Antegrade cystourethroscopy
Figure 11 Schematic of the PCCL procedure (discussed further in the accompanying article)
Antegrade cystourethroscopy is a procedure that is most commonly used in the author’s practice for the removal of bladder stones in male and female cats (percutaneous cystolithotomy, PCCL), and for diagnostic imaging in small female cats or male cats in which an intervention might be needed (biopsy, stent placement, etc). This is performed through a 1 cm skin incision over the apex of the urinary bladder. Through this small incision, on the ventral midline, the urinary bladder is isolated and stay sutures are used to secure it to the body wall (Figure 11). Using a screw trocar with a diaphragm (Figure 12), a small stab incision is made into the apex to maintain a closed system for bladder distension during access for the rigid endoscope. Then, from an antegrade direction, the urinary bladder, proximal ureterovesicular junctions and proximal urethra can be carefully evaluated (Figure 13). Once cystourethroscopy is complete, the hole for the trocar is closed using Figure 12 Screw trocar absorbable suture material and the used to maintain irrigation and distension abdominal wall is closed in three layers during antegrade routinely. This is considered an outcystourethroscopy (PCCL procedure) patient procedure.
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Figure 13 Antegrade cystourethroscopy (PCCL procedure) in a male cat with bladder stones. (a) Normal bladder wall. (b) Stones (calcium oxalate) on the dependent surface of the bladder wall. (c) Proximal urethra showing the ureteral papilla and the slits of the ureterovesicular junction. (d) Midurethral lumen viewed with the rigid cystoscope
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R E V I E W / Cystourethroscopy
Abnormalities
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Figure 14 Urethroscopic images of a male cat during semi-rigid cystourethroscopy. The image quality is not as good as that provided by a rigid endoscope. This is a 0° endoscope so the image does not need to be angled and the lumen should remain in the center of the screen. (a) Distal penile urethra, (b) mid-pelvic urethra, (c) proximal pelvic urethra and (d) ureteral papilla in the proximal urethra
Male cats In male cats cystourethroscopy can either be performed in a retrograde manner using a semi-rigid endoscope or in an antegrade manner using a 1.9 mm rigid cystoscope (see page 39). The semi-rigid scope allows visualization of the penile urethra but the image quality and ability to irrigate, biopsy or perform therapeutic interventions is limited due to the absence of, or only a very small, working channel (Figure 14).
The most common abnormalities seen in the urethra in the author’s experience are strictures, stones and tumors (Figure 15). Interestingly, strictures are most commonly seen by the author in the pelvic urethra after trauma or congenitally in the very proximal urethra at the ureterovesicular junction. Ectopic ureteral openings are not commonly seen in cats and the operator should realize that the normal feline ureteral openings are found in the proximal urethra, rather than the bladder, and thus these are not ectopic. In the urinary bladder, tumors, stones, polyps and glomerulations, associated with feline idiopathic cystitis, can be seen endoscopically. A diagnosis can be obtained using various instruments/biopsy methods (cup biopsy forceps, basket, snare) (Figure 16). Therapeutically, wires, catheters, snares, lasers and stents can be employed (Figure 17), and this is expanded on in the accompanying article.
Figure 15 Endoscopic biopsy cup forceps being used to
Figure 16 Bladder stone being retrieved with a stone
sample a bladder tumor
retrieval basket during PCCL in a male cat
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Figure 17 Urethral abnormalities seen during urethroscopy in three different female cats. (a) Congenital urethral stricture located between the ureteral openings and the bladder trigone. Note that the ureteral openings (black arrow) are on the distal side of the stricture. The narrow urethral opening is shown with a red arrow. (b) Bladder stones within the urethral lumen. (c) Proximal urethral transitional cell carcinoma causing an obstruction
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R E V I E W / Cystourethroscopy
KEY POINTS < Cystourethroscopy is a valuable diagnostic tool in the evaluation of feline patients with lower urinary tract disease.
< Care should be taken as the feline urethra and bladder are very fragile and can be easily traumatized during cystourethroscopy.
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< Therapeutic cystourethroscopy is being more commonly employed in feline patients for the treatment of stone disease, incontinence, neoplasia and ureteral obstructions/disease.
< To perform this technique safely and effectively suitable
training should be undertaken to ensure appropriate technique is used and the best instruments are available.
< Knowledge of the anatomical normals is vital in the diagnosis of disease.
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Funding
The author received no specific grant from any funding agency in the public, commercial or not-forprofit sectors for the preparation of this article.
Conflict of interest
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The author is an advisor for Infiniti Medical and Norfolk Vet Products.
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References
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Current veterinary therapy XV. Elsevier. In Press 2014. Berent A. Urinary stenting in dogs and cats. In: Polzin J and Bartges D (eds). Nephrology and urology of small animals. Wiley Blackwell, 2011, pp 329–339. Berent A. Urologic interventional techniques in the feline patient. In: August JR (ed). Consultations in feline internal medicine. Vol 6. St Louis: Saunders, Elsevier, 2009, pp 516–532. Weisse C and Berent A. Potential applications of interventional radiology in veterinary medicine. J Am Vet Med Assoc 2008; 233: 1564–1574. Berent A, Weisse C and Bagley D. Feline ureteral stenting for the treatment of benign ureteral obstruction in cats: 2006–2012. J Am Vet Med Assoc. In Press 2014. Horowitz C, Berent A, Weisse C, Langston C, and Bagley D. Predictors of outcome for cats with ureteral obstructions after interventional management using ureteral stents or a subcutaneous ureteral bypass device. J Feline Med Surg 2013; 15: 1052–1062. Defarges A, Berent A and Dunn M. New alternatives for minimally invasive management of uroliths: ureteroliths. Compend Contin Educ Pract Vet 2013; 35(3): E4. Defarges A, Dunn M and Berent A. Lithotripsy and minimally invasive removal of lower urinary tract stones: lower urinary tract uroliths. Compend Contin Educ Pract Vet 2013; 35(1): E1. Holmes ES, Weisse C and Berent A. Use of fluoroscopically guided percutaneous antegrade urethral catheterization for the treatment of urethral obstruction in male cats: 9 cases (2000–2009). J Am Vet Med Assoc 2012; 241: 603–607. Zaid MS, Berent AC, Weisse C and Caceres A. Feline ureteral strictures: 10 cases (2007–2009). J Vet Intern Med 2011; 25: 222–229. Runge J, Berent A, Weisse C and Mayhew P. Transvesicular percutaneous cystolithotomy for the retrieval of cystic and urethral calculi in dogs and cats: 27 cases (2006–2008). J Am Vet Med Assoc 2011; 239: 344–349. Berent A. Ureteral obstructions in dogs and cats: a review of traditional and new interventional diagnostic and therapeutic options. J Vet Emerg Crit Care 2011; 21: 86–103.
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