Transurethral resection in the management of urethral and prostatic neoplasia in 6 dogs

OBJECTIVE: To assess cystoscopic transurethral resection (TUR) for the palliative management of dogs with neoplastic infiltration of the urethra. STUDY DESIGN: Prospective clinical trial. ANIMALS: Six client-owned dogs. METHODS: Cystoscopic examination and electrosurgical TUR were performed in dogs with urination difficulties caused by prostatic or urethral neoplasia. TUR was performed in a retrograde manner in female dogs and antegrade in male dogs via exploratory celiotomy and ventral cystotomy. Cystoscopic examination was used to determine the extent of neoplastic involvement of the urethra. TUR involved piecemeal removal of neoplastic tissue from the urethral lumen using an electrocautery cutting loop. Hemorrhage was controlled with a cystoscopic cauterized roller-ball. In 2 male dogs, intraoperative radiation therapy (IORT) was used to treat both prostatic neoplasia and the sublumbar lymph node bed. Surgical technique, complications, adjuvant treatment, and outcome were recorded. RESULTS: TUR was performed in 3 male dogs with prostatic carcinoma and 2 female dogs with urethral transitional cell carcinoma (TCC). In 1 female dog, TUR was attempted but not successful because of cystoscope diameter. Iatrogenic urethral perforation occurred during TUR in 3 dogs. In 2 dogs, prolonged exposure to lavage fluid resulted in clinical and biochemical abnormalities consistent with TUR syndrome. Dysuria resolved in 5 dogs within 10 days of TUR. Treatment-related complications included urinary tract infection and tumor seeding. Local tumor progression and metastasis occurred in all dogs. CONCLUSIONS: TUR (in combination with chemotherapy+/-IORT) resulted in rapid palliation of urination difficulties in male dogs with prostatic carcinoma. In female dogs with urethral TCC, however, electrosurgical TUR cannot be recommended because of a high intra- and postoperative complication rate with no improvement in postoperative management compared with historical reports of tube cystostomy. CLINICAL RELEVANCE: TUR is a novel alternative for the palliation of male dogs with prostatic carcinoma. In female dogs with urethral TCC, electrosurgical TUR does not provide any advantages compared with tube cystostomy.     

Radiologic study of the canine urethra

The structure and function of the canine urethra were studied during retrograde and voiding urethrography in 9 male and 8 female dogs. The lumen of the prostatic portion of the urethra was variable in diameter. During retrograde urethrography, the lumen was narrow with streaks of contrast medium outlining mucosal folds, but during voiding, it was dilated and a spindle-shaped seminal hillock was detected. Retrograde urethrography revealed other regions of the urethra of males and females had a smooth radiographic outline. During voiding urethrography, characteristic identical urethral contractions were observed in the caudal portion of the pelvic urethra (male) and in the caudal half of the urethra (female). Contractions were progressive, occurred where striated muscle was present in the urethral wall, and resulted in an intermittent flow of urine from the urethra. In the male, contractions had a rate of 2.02 +/- 0.23 contraction/s and 1.65 +/- 0.53 in the females. Contractions may have a role in the controlled voiding of small volumes of urine necessary for the repeated marking of territory, in the passage of the ejaculate along the male urethra during copulation, and in the clearance of any residual urine from the urethra at the completion of micturition.     

DIMENSIONS OF THE PROSTATIC AND MEMBRANOUS URETHRA IN NORMAL MALE DOGS DURING MAXIMUM DISTENSION RETROGRADE URETHROCYSTOGRAPHY*

Prostatic and membranous urethral diameter was measured in 24 normal mature male Beagle dogs during maximum distension retrograde urethrocystography. This technique involved retrograde urethral distension by infusion with contrast medium until the urinary bladder was distended and the vesicourethral junction remained opened as observed by fluoroscopy. Lateral and ventro-dorsal radiographs were made during subsequent injections of 5–10 ml of contrast medium. The prostatic urethra was consistently greater in diameter than the membranous urethra. However, the numerical ratio between the prostatic urethral diameter and the membranous urethral diameter varied among these dogs by a factor of 2 at the numerical extremes.     

An end‐to‐end urethral anastomosis after inguinal tunnelization: a new technique in a dog

An 8‐year‐old male dog was presented with a peri‐urethral intrapelvic mass with the characteristics of a sarcoma on computed tomography and cytology evaluation. A two‐step procedure leading to a permanent urinary diversion was performed. During the same procedure, the caudal pelvic urethra and mass were resected and an extrapelvic anastomosis of the pelvic portion of the urethra to its penile portion was performed after passage of the pelvic urethra through the inguinal canal. The procedure successfully produced a tension‐free end‐to‐end urethral anastomosis and no complications were observed during the postoperative period. Histologically, the lesion was reported as a narrowly excised liposarcoma. A 4‐week course of curative intent of radiotherapy was initiated 2 weeks after surgery. Eight months later, the dog was free of clinical signs.     

Sagittal pubic osteotomy in the investigation and treatment of intrapelvic neoplasia in the dog

Sagittal pubic osteotomy was used as the surgical approach in 24 cases of intrapelvic neoplasia in the dog. Thirteen cases involved the urethra, seven cases the colorectum, one case the prostate and three cases the iliac periosteum. Surgical excision was performed in 10 cases of urethral neoplasia, four cases of rectal neoplasia, two cases of periosteal fibrosarcoma and one case of chondrosarcoma. The remaining cases were assessed as inoperable due to the extent of disease and euthanasia was carried out. Access to intrapelvic structures via a caudal midline laparotomy, perineal or dorsal routes or via an episiotomy is severely limited. The structures within the pelvic canal most likely to require surgical attention are the urethra, rectum and prostate. Procedures which require wide excision, accurate anastomotic techniques or relocation of intrapelvic organs necessitate an approach that allows generous exposure. A simple method of pubic osteotomy has been employed which has allowed resection of intrapelvic neoplasms.     

Use of a retained urethral catheter in three dogs with prostatic neoplasia.

Percutaneous nephrostomy catheters modified by cutting off the tubing connectors were implanted in three dogs with prostatic neoplasia to relieve or prevent stranguria. One catheter was implanted with a guide wire through a perineal urethrotomy, and two catheters were implanted via celiotomy and cystotomy. Morbidity and complications were minimal. Inflammation of the abdominal incision was present from day 4 to day 8 in the dogs with celiotomy. Urinary incontinence was continuous in one dog and intermittent in two dogs. Hematuria occurred in two dogs. The retained urethral catheter was a suitable palliative treatment for urethral obstruction in three dogs with prostatic neoplasia.     

MRI characteristics of canine prostatic neoplasia

Magnetic resonance imaging (MRI) has been used to evaluate dogs with suspected prostatic neoplasia, however, published studies describing MRI characteristics of canine prostatic neoplasia are currently lacking. The aims of the current retrospective case series study were to describe MRI findings of the pelvic region in dogs with a histopathologic or cytologic diagnosis of prostatic neoplasia. Retrospective analysis of these images was then performed by a board-certified veterinary radiologist for shared imaging characteristics. The most consistent characteristics were heterogeneous hyperintensity of the tumor on T2-weighted images (10/10) and short tau inversion recovery images (10/10), prostatic capsular margin distortion by the tumor (10/10), cavitations (10/10), complete effacement of the prostatic architecture (9/10), neurovascular bundle (NVB) compression or invasion (9/10), heterogeneous isointensity of the tumor on T1-weighted images (9/10), and strong contrast enhancement of the tumor (8/10). Additional features included an overlying pattern of distorted radiating striations (7/10), regional lymphadenomegaly (5/10), mineralization within the mass (5/10), urinary bladder trigone involvement (6/10), and post-prostatic urethral involvement (7/10). These findings supported the use of MRI as an adjunct imaging modality for diagnosis and therapeutic planning of prostatic neoplasia and including prostatic neoplasia as a likely differential diagnosis for dogs with these MRI characteristics.     

Canine prostatic fluid: techniques of collection, quantitative bacterial culture, and interpretation of results

Specimens of prostatic fluid were collected by ejaculation from 104 dogs after collection of a specimen of urethral contents and after collection of a urine specimen by antepubic cystocentesis. For purposes of data analysis, results of bacterial culture of the specimens were grouped according to individual colony counts in each specimen group (ie, urine, urethra, prostatic fluid). For purposes of this study, prostatic infection was defined as greater than or equal to 2 log10 of one or more bacterial species in prostatic fluid over the number of colonies of the same species in the paired urethral specimens.     

Prostatic squamous metaplasia in a cat with interstitial cell neoplasia in a retained testis

An 11-year-old cat with a retained testis was presented with a chronic history of dysuria and bladder atony. Medical therapy failed to alleviate the clinical signs. Contrast radiography demonstrated a diffusely narrowed urethra. During a celiotomy and prepubic urethrostomy, a retained testis, stenosed urethra, and irregularly enlarged prostate were observed. Histopathologic diagnosis was retained testis with a well-differentiated interstitial cell tumor, a poorly differentiated interstitial cell tumor, and marked squamous metaplasia of the prostatic epithelium with suppurative prostatitis. Neoplastic interstitial cells were immunoreactive for Melan A, consistent with reports of Melan A expression in steroid hormone-producing tissue. This is the first report of prostatic squamous metaplasia associated with testicular neoplasia in a felid.     

Prostatic carcinoma causing urethral obstruction and obstipation in a cat

A 9-year-old intact male cat was presented for vomiting and straining to defecate. A large abdominal mass was palpated. The urinary bladder was full and non-expressible. Exploratory laparotomy revealed that the mass was compressing the colon and encircling the urethra caudal to the bladder. The mass was removed, the urethra transected, and the urinary bladder marsupialized to the ventral abdominal wall to allow urine drainage. Histopathologic examination of the mass revealed a prostatic carcinoma. The cat died approximately 6 weeks after removal of the mass. This is the first reported case of a prostatic carcinoma causing urethral obstruction and obstipation in a cat.     

ULTRASONOGRAPHIC APPEARANCE OF URETHRAL TRANSITIONAL CELL CARCINOMA IN TEN DOGS

The mucosal margin of the urethra is best assessed by positive contrast urethrography, but ultrasonography offers complementary information such as urethral wall thickness and size of medial iliac lymph nodes. Ultrasonography of the urethra is quick, noninvasive and does not require sedation or general anesthesia. In patients with complete urethral obstruction, ultrasonography may be the only way to image the urethra. Twelve dogs which were presented to Tufts University School of Veterinary Medicine with clinical signs referable to the urinary bladder, urethra or vagina were examined ultrasonographically. Seven were neutered females and five were neutered males. Each dog had a hyperechoic, nonshadowing line at the epithelial surface of the proximal urethra. In the seven female patients and one of the males, the urethral wall was also thick and hypoechoic to surrounding tissue. In the other males, the urethral epithelial changes were at the level of the prostate, and the limits of the urethra were not visible. In six dogs, the urethral change was the only abnormality seen, while in six, bladder wall, bladder luminal and/or prostatic parenchymal changes were also detected. Three patients had hydronephrosis, and one had enlarged medial iliac lyumph nodes. Biopsies were obtained via suction with urinary catheterization (n = 6), exploratory celiotomy (n = 3), urethroscopy (n = 2), or at post-mortem (n = 1). A histopathologic diagnosis of urethral transitional cell carcinoma was obtained in ten dogs. The ultrasonographic appearance was not pathognomonic for transitional cell carcinoma, as one dog with transitional cell dysplasia and one dog with severe ulcerative and necrosupperative cystitis and urethral stricture had similar findings.     

Urinary Incontinence after Prostatectomy in Dogs

Eleven dogs with prostatic disease were treated by total prostatectomy. Urinary incontinence persisted in three of nine dogs, two of which were also incontinent before surgery. The incidence of postoperative incontinence may be reduced by undermining the prostatic capsule to preserve as much prostatic urethra as possible. The risk of postoperative incontinence appeared greater if there was prostatic neoplasia or preoperative urinary incontinence.     

Neodymium:yttrium-aluminum-garnet laser ablation of a urethral web to relieve urinary outflow obstruction in a horse.

An 8-year-old Hanoverian gelding was examined because of urine dribbling and urethral obstruction. Mild proprioceptive deficits of the left hind limb were evident during neurologic examination. Ultrasonography per rectum revealed dilatation of the pelvic portion of the urethra. Endoscopy of the urethra revealed 2 webs of tissue: 1 was located 10 cm proximal to the external urethral opening; the other was located 65 cm proximal to the external urethral opening and prevented passage of the endoscope into the urinary bladder. The mass was ablated with a neodymium:yttrium-aluminum-garnet laser, using a transendoscopic noncontact technique. On follow-up examination 6 months after laser surgery, an endoscope could easily be passed into the bladder, and no urethral web was seen. The horse was able to void a stream of urine but continued to dribble urine intermittently. The proximal location of the urethral lesion in this horse would have made use of traditional surgical methods problematic, whereas transendoscopic laser photoablation was easy and effective.     

Vaginourethroplasty as a salvage procedure for management of traumatic urethral rupture in a cat

This report describes a cat that suffered pelvic urethral rupture associated with multiple pelvic fractures. A vaginourethroplasty was performed as a salvage procedure, via intrapelvic anastomosis of the proximal urethra to the caudal vagina, following failure of a primary urethral anastomosis. Urinary diversion was achieved via tube cystostomy and a vagino-urethral catheter was maintained for 3 days postoperatively. Anterograde cystourethrography was performed at 7 days and 14 days postoperatively. Absence of contrast leakage from the vagino-urethral anastomosis was documented at 14 days postoperatively and the tube cystostomy was removed. An Escherichia coli urinary tract infection was treated following removal of the tube cystostomy and subsequent urine culture revealed no evidence of urinary tract infection. The cat retained normal urinary continence and elimination behaviour during the 7-month follow-up period. Vaginourethroplasty could be considered as a salvage option for management of traumatic pelvic urethral rupture in the neutered female cat.     

Canine prostatic diseases

Prostatic diseases such as benign hyperplasia, prostatic cysts, acute bacterial prostatitis, chronic bacterial prostatitis, prostatic abscessation, and prostatic neoplasia are discussed. Also discussed are diagnostic techniques such as prostatic palpation and massage, evaluation of semen and urethral discharge, and radiography.     

Costal bone changes similar to hypertrophic osteopathy associated with pulmonary and abdominal mesothelioma in a dog

An 8-year-old male Irish Setter was admitted because of nonweight bearing lameness of the left forelimb. Radiography failed to reveal any bony lesions of the forelimb; however, extensive periosteal new bone formation over most rib surfaces and an atypical cardiac silhouette suggestive of a mediastinal mass with pleural effusion were observed. New bone formation was seen on the ilium and a filling defect in the urethra, distal to the prostate, was apparent with contrast urethrocystography. Necropsy revealed scirrhous mesothelioma of the thorax and abdomen, multifocal periosteal exostoses, paraprostatic cyst, and benign prostatic cystic hyperplasia. Tumor cells were associated with the periosteal exostotic costal bone. The specific cause of the lameness was not determined.     

Traumatic urethral avulsion at the preputial fornix in a cat

A cat with pelvic fractures from being hit by a car had voided no urine in 13 hours despite iv administration of fluids. Abdominal radiography had revealed the pelvic fractures and apparently intact urinary bladder. Urine did not flow from a urethral catheter, and contrast radiography revealed the catheter to be extra-urethral within the penis. Intravenous pyelography revealed intact ureters and urinary bladder; celiotomy confirmed intact urinary bladder. Cystotomy and normograde urethral catheterization allowed localization of the ruptured urethra within the deep subcutaneous tissues of the caudal portion of the abdomen. After closure of the cystotomy and celiotomy incisions, perineal urethrostomy was performed.     

Urethral recess in two male llamas

Contrast radiography revealed a urethral recess in 2 male llamas, and, in 1, an incidental cyst in the wall of the pelvic urethra. The urethral recess was similar to that found in cattle, sheep, goats, and camels. The presence of a urethral recess in llamas makes catheterization of the urinary bladder as difficult in this species as it is in the other species with urethral recesses.     

Immediate urodynamic and anatomic response to colposuspension in female Beagles

OBJECTIVE: To characterize urodynamic function and anatomy before and after colposuspension in anesthetized female Beagles. ANIMALS: 12 adult female Beagles. PROCEDURE; During general anesthesia (thiopental sodium induction and halothane maintenance), urethral pressure profiles, leak point pressure measurements with a 50-ml bladder volume, positive contrast cystograms, and retrograde vaginourethrocystograms were performed. A caudal midline laparotomy was used to perform colposuspension. Urodynamic and radiographic studies were repeated after surgery. RESULTS: Leak point pressures were increased (120 to 168.9 cm H2O), and maximum urethral closure pressures decreased (43.7 to 19.3 cm H2O ) after colposuspension. The urethra and bladder were moved cranially; the external urethral orifice was positioned closer to the pelvic cavity, and the neck of the bladder was positioned more cranially into the abdomen. Length of the urethra, as measured by use of vaginourethrocystograms, was increased by 3%. As measured by use of urethral pressure profiles, total profile length was increased by 19.9%, and functional profile length was increased by 19.2%. CONCLUSIONS AND CLINICAL RELEVANCE: Increased leak-point pressure correlated with the expected clinical improvement attributable to colposuspension. Increased exposure of the urethra to abdominal and pelvic cavity pressures may be the mechanism by which incontinent dogs become continent after colposuspension. Results of the leak-point pressure test may correlate with clinical behavior before and after colposuspension for treatment of incontinence.     

Retrograde CT urethrography using a power injector quantitatively reveals effects of bladder distension on urethral size in healthy male Beagle dogs

Quantitative analysis of the normal retrograde urethrogram is well reported in radiography, but studies on CT urethrography are lacking. Recently, a method of retrograde CT urethrography using a power injector was described. The purpose of the current, prospective, analytical study was to quantify the urethral size of five, healthy, intact, male Beagle dogs using retrograde CT urethrography and a power injector. With the injection rate of the power injector set at 0.3 mL/s, 1 mL/kg of diluted contrast medium (15 mg I/mL) was injected, and a CT examination was performed. The state of the initial urethrogram taken was defined as “empty bladder.” The same procedures were repeated with the injection of an additional 1 mL/kg of diluted contrast medium until the ureteral reflux was seen (distended bladder). There was a significant difference in volumes between the empty and distended bladder, but the membranous urethra showed the least difference (P = .0044) among the three regions (P < .0001 for the prostatic and penile urethra). Urethral diameters at six sites were measured from sagittal images, and the sites of measurements were adopted from the earlier radiographic studies. The most significant difference in the urethral diameters between the empty and distended bladder occurred at the cranial and middle prostatic urethra (P < .0001). The results of this study can be useful for interpreting the results of retrograde CT urethrography. Care must be taken when narrowing is suspected at the prostatic urethra, and if necessary, further distension of the urinary bladder should be tried.