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Overview of small animal urinary tract endoscopy (Proceedings)
Cystoscopy has not received much attention in clinical practice until recently.
Cystoscopy has not received much attention in clinical practice until recently. Equipment has become more cost-effective and is adaptable for other procedures such as rhinoscopy and laryngoscopy. Residents are being trained in cystoscopy at universities and thus are capable of performing this procedure in private practice. They will need technical assistance-technicians who know how to operate the equipment before, during and after the procedure, and know the "ins and outs" of performing a safe and timely endoscopic procedure.
Cystoscopy is defined as the visualization of the vagina, urethral opening, urethra, bladder and ureteral openings. Direct visualization, magnification, and optimal lighting are just a few of the advantages over invasive surgical procedures. Indications for performing cystoscopy include chronic urinary tract infections, neoplasia, trauma, hematuria, stranguria, pollakiuria and cystic and/or urethral calculi. General Anesthesia is required for this procedure.
Cystoscopies are considered a sterile procedure at the VMTH. Our rigid endoscopes and light cables are packaged and steam sterilized according to manufacturer's recommendations. Our flexible endoscopes are disinfected in 2.6% Glutaraldehyde solution and placed on a sterile drape. Sterile camera drapes are used over our cameras and camera cords, and all participants require sterile gowns and gloves. Patient preparation includes gentle shaving and surgical scrub around the prepuce or vaginal area and tip of the penis. Tails of females dogs and cats are wrapped with gauze and taped away from the field. We also flush the prepuce with a weak Betadine solution. The patient is then draped at the appropriate area. In male dogs sterile gloves are used to extrude the penis to allow the cystoscope to intubate the urethra.
Patient positioning in female dogs varies with the clinician's preference. Most endoscopists favor right or left lateral recumbency with the hind end as close to the end of the table as possible. Ventral-dorsal can also be utilized. Male dogs are always in lateral recumbency. Our male patients are placed with the left side down, which affords the endoscopist a better view of the video screen. Cats can be placed in lateral or dorsal recumbency.
Instrumentation differs between male and female patients. Male dogs require small outer diameter (O.D.) flexible endoscopes. An example is the Storz Flex X2 with an O.D. of 2.5 mm (7.5fr), a working length of 70 cm. and a 1.2 mm (3.6 fr.) biopsy channel. Additionally, the Flex X2 can also be used as a bronchoscope for smaller dogs and cats.
Female dogs need a rigid cystoscope, or telescope. An example is the Wolf Panview II telescope which has a 4mm (12 fr.) O.D., a 30 cm working length and a 25 deg. angle-of-view. This cystoscope would be adequate for large female dogs. The 25 deg. angle-of-view allows for a wider area of the bladder to be examined in one field.
In order to fully visualize the urinary tract, especially the urethra, the cystoscope must have ports for infusion/removal of fluids, retrieval of uroliths or foreign bodies and biopsy of masses or lesions. Flexible cystoscopes have a biopsy channel that is used for both flush and retrieval. Keep in mind that the channel size of these endoscopes is small--biopsy forceps can be difficult to find and mechanical suction should not be used, as it could collapse the channel. Telescopes for female dogs must have a sheath that fits over the working length and attaches near the lens. The sheath provides 2 ports for fluid infusion and retrieval, and a biopsy channel. Remember that the sheath will add to the outer diameter of the telescope (the example above will widen the telescope to 6.5mm [19.5 fr.]).
Feline cystoscopy is rarely performed at the VMTH and requires smaller endoscopes, such as a Karl Storz semi-rigid telescope with a 1.2 mm (3.6 fr.) O.D. and 20 cm working length for use in females, with no sheath and therefore no instrumentation available. Custom-made flexible endoscopes for male cats have a 1.1mm (3.2 fr) O.D. and a 55 cm working length. Be aware that some of these cystoscopes are not fully immersable for cleaning and disinfection. Check with the manufacturer if you are unsure.
Accessory instruments such as stone-retrieval baskets, foreign body retrieval forceps and balloon dilation catheters are available. You will need to know the channel size of your scope to order the appropriate size instrument.
Video systems can be attached to the cystoscope using a camera attachment for still images or video capture. A c-clamp adapter will attach to the cystoscope's viewing lens, allowing for a more comfortable and interactive procedure.
Procedure-Once the cystoscope is attached to the light source and camera, attach a 1 liter bag of saline flush to the biopsy port of the endoscope or accessory port of the sheath. The endoscopist should control the rate of flush infusing at the ports. A syringe attached to the administration set may be needed to distend the urethral lumen for optimum visualization. Always be aware of how much fluid has been infused! Keeping the endoscopist apprised of how much fluid has been infused in 100ml increments will remind the endoscopist to drain the bladder over time. Also gently palpate the bladder to ensure that it isn't too distended. Try to keep air out of the urinary tract, as bubbles will form and disrupt visualization. In females pinching the vulva closed will help distend the vaginal vault with fluid for better visualization.
In females the urethral opening will be ventral to the vaginal lumen and appear as a longitudinal slit. Once in the urethra, fluid should distend the folds and smooth out the mucosa, which should appear light pink and vascular. In males, the urethral mucosa should be light pink and a uniform shape throughout, with a slight narrowing at the end of the os penis and prostatic urethra.
Once in the bladder the endoscopist may need to remove the urine and replace with saline for maximum visualization. The normal bladder wall when distended should be light pink with visible sub-mucosal blood vessels. When distended the ureteral openings can be identified. They are located at the dorsolateral aspect of the trigone area where the bladder mucosa begins and the urethra ends. Urine should normally be seen "jetting" from both ureters. Biopsies can be obtained once all structures have been examined since blood from the biopsies could interfere with visualization.
Abnormal findings in the Urinary Tract System–
Neoplasia—Transitional Cell Carcinoma is the most common urinary tract tumor, usually found in the trigone area and could cause complete obstruction. It can appear as a raised mass in the bladder or have fringe-like projections when seen in the urethra. It is discovered most often in female dogs. Less commonly seen are leiomyomas, squamous cell carcinomas, and adenocarcinomas.
Inflammation—Urethritis and Cystitis grossly appear as hyperemic, thickened and edematous mucosal walls. Petechiations in the bladder, also called glomerulations, can also indicate an inflammatory process. As the bladder walls become thicker, distending the bladder becomes more difficult. Mucosal vessels also become more apparent. Polyps may also develop in the bladder from chronic inflammation. Urethral strictures can sometimes occur in severe cases. Strictures can be distended with urethral balloon dilators.
Prostatitis—Inflammation can occur at the prostatic area appearing as roughened and discolored mucosa. As a result, the urethra can stricture in that area causing complete occlusion.
Urethral and Cystic Calculi—Calculi can commonly occur in both dogs and cats. Size can range from gritty sand to large stones. Small stones can be removed with a basket snare that is placed through the biopsy channel. Once the stone is captured in the basket the cystoscope and basket are removed from the patients as one unit. Larger stones can either be removed surgically or broken into smaller pieces using laser lithotripsy and hydropropulsion.
Ectopic Ureters—Endoscopy is the procedure of choice when ureteral openings are misplaced in the urethra or vaginal area, causing urinary incontinence. Ureters can also be correctly placed but have an abnormal configuration. Ectopic ureters can be either unilateral or bilateral
Renal Hematuria—this disease is defined as blood coming from a ureter (from the kidney) with no definable cause. This idiopathic disease is usually unilateral. Cystoscopy is the procedure of choice to determine which kidney is affected, and, in cases of massive hemorrhage, should be removed.
It is my hope that when cystoscopy is integrated into your practice these notes will help you get "up and running" and be an even more valuable member of the veterinary team!