Evaluation of Temporary Urethral Stents in the Management of Malignant and Nonmalignant Urethral Diseases in Dogs

Urethral stent placement is a minimally invasive interventional procedure commonly performed by specialists to alleviate urethral obstruction. However, the availability of urethral stents is limited by their high cost and the need for special equipment. The aim of this retrospective study was to describe the construction and placement of an inexpensive temporary urethral stent and to report on its outcome in managing dogs with naturally occurring urethral disease. Temporary stents were placed in the urethra of 17 dogs with malignant and nonmalignant urethral pathologies. The most common indication for temporary stent placement was urethral obstruction. In this population, urethral patency was restored in all dogs. The most frequently reported complication was urinary incontinence. To manage this complication, dogs were diapered. Temporary urethral stents served as a durable and inexpensive alternative to expanding metallic stents. Because temporary stents were constructed from readily available materials and inserted without special equipment, practitioners capable of catheterizing the urethra can insert them on demand

Urinary metals in a spontaneous canine model of calcium oxalate urolithiasis.

Calcium oxalate urolithiasis is a common and painful condition in people. The pathogenesis of this disease is complex and poorly understood. Laboratory animal and in vitro studies have demonstrated an effect of multiple trace metals in the crystallization process, and studies in humans have reported relationships between urinary metal concentrations and stone risk. Dogs are a spontaneous model of calcium oxalate urolithiasis, and the metal content of canine calcium oxalate stones mirrors that of human stones. The aim of this study was to test for a relationship between urinary metals and calcium oxalate urolithiasis in dogs. We hypothesized that urinary metals would differ between dogs with and without calcium oxalate urolithiasis. Urine from 122 dogs (71 cases and 51 stone-free controls) was analyzed for calcium and 12 other metals. The cases had higher urinary calcium, copper, iron, and vanadium and lower urinary cobalt. Higher urinary vanadium in the cases was associated with being fed a therapeutic stone-prevention diet. Urinary calcium had a strong positive correlation with strontium and moderate positive correlations with chromium, nickel, and zinc. The results of this study complement the findings of similar human studies and suggest a potential role of trace metals in calcium oxalate urolithiasis. Further investigation into how trace metals may affect stone formation is warranted

Prevalence and Predictors of Radiographically Apparent Upper Urinary Tract Urolithiasis in Eight Dog Breeds Predisposed to Calcium Oxalate Urolithiasis and Mixed Breed Dogs

Data on upper urinary tract (UUT) uroliths in dogs are important to understanding their etiology. The aim of this retrospective case-control study was to determine the prevalence and identify predictors of radiographically apparent UUT uroliths in dog breeds at increased risk for calcium oxalate uroliths (CaOx risk breeds) and mixed breed dogs. Radiologist reports of three-view abdominal radiographs were reviewed from 251 purebred dogs of 8 CaOx risk breeds and 68 mixed breed dogs. UUT uroliths were more common in CaOx risk breeds than mixed breed dogs (23% versus 6%, respectively; OR = 4.8, 95% confidence interval [CI] 1.7–18.9, p < 0.001). UUT uroliths were more common in dogs with lower urinary tract (LUT) uroliths (predominantly calcium-containing) than those without (41% versus 5%, respectively; OR = 13.6, 95% CI 6.3–33.1, p < 0.001), and LUT uroliths predicted the presence of UUT uroliths in the multivariable regression (OR = 6.5, 95% CI 2.8–16.7, p < 0.001). Increasing age (p < 0.001) and lower body weight (p = 0.0016) were also predictors of UUT urolith presence in the multivariable regression. The high prevalence of UUT uroliths in dogs with LUT uroliths supports a shared mechanism for their formation

Characteristics of the 122 study dogs.

<p>Cases are dogs with confirmed CaOx urolithiasis, and controls are stone-free as determined by abdominal radiography. Age at the time of urine sampling is reported as mean ± standard deviation, and weight is reported as median (range).</p

Reduced multivariable regression models for the effects of CaOx stone status and environmental factors on log-transformed urinary element-to-creatinine ratios (Ca/Cre, Co/Cre, Cu/Cre, Fe/Cre and V/Cre).

<p>For variables with 1 degree of freedom, the status corresponding to the estimate is in parentheses.</p

Urinary element-to-creatinine ratios in dogs with CaOx urolithiasis (cases) and stone-free controls.

<p>Values are reported in mg/g for urinary Ca/Cre and μg/g for the other urinary element-to-creatinine ratios.</p

Heat map of correlation coefficients between urinary metals in dogs with and without CaOx urolithiasis.

<p>Correlation coefficients in bold font had p-values < 0.05.</p