Canine retrograde urohydropropulsion. Lessons from 25 years of experience

Urethral entrapment by an overlapping dislocation of the pubic symphysis in a cat

Case summary

A 1-year-old neutered male domestic shorthair cat was referred with suspected uroperitoneum. Ultrasonography showed peritoneal effusion. CT further revealed a bilateral sacroiliac joint disruption associated with an overlapped dislocation of the pubic symphysis, resulting in an abnormal trajectory of the urethra with extramural urethral compression. An open reduction and internal fixation of the pubis with correction of the urethral trajectory was performed under general anaesthesia. The uroperitoneum was determined to originate from a cystocentesis.

Relevance and novel information

This report describes an unusual case of urethral obstruction secondary to overlapping dislocation of the pubic symphysis with urethral entrapment and concurrent bilateral sacroiliac luxation. To the authors' knowledge, acute urethral obstruction owing to fractures of the pubis, without urethral laceration, has never been described.

Comparison of radiographic methods for detecting radiolucent uroliths in dogs

The purpose of this study was to evaluate and compare positive cystography techniques at 5%, 10%, and 20%, as well as three different double-contrast protocols for detecting radiolucent uroliths with a diameter of less than 3.0 mm in dogs. Six cadavers were used, one was selected at random to represent the negative control, and the others were submitted to urolith implantation in the bladder by urethral catheter. Three radiology professionals blindly accessed ventrodorsal and -lateral projections of each test. Contrast at 20% showed greater diagnostic sensitivity, but with greater difficulty identifying the number and size of the uroliths. Consequently, double-contrast techniques are better and should be used for diagnostic and therapeutic planning. Sensitivity and specificity tests demonstrated that positive 5% cystography and different concentrations of double contrast obtained better results in terms of sensitivity and specificity. However, due to the presence of a greater amount of artifacts in the 5% cystography, it is suggested that double contrast is used for this purpose, especially with the removal of contrast excess (protocol 2).

Computed tomographic assessment of retrograde urohydropropulsion in male dogs and prediction of stone composition using Hounsfield unit in dogs and cats

Background

Persistent uroliths after a cystotomy in dogs are a common cause of surgical failure.

Objectives

This study examined the following: the success rate of retrograde urohydropropulsion in male dogs using non-enhanced computed tomography (CT), whether the CT mean beam attenuation values in Hounsfield Units (mHU) measured in vivo could predict the urolithiasis composition and whether the selected reconstruction kernel may influence the measured mHU.

Methods

All dogs and cats that presented with lower urinary tract uroliths and had a non-enhanced CT preceding surgery were included. In male dogs, CT was performed after retrograde urohydropropulsion to detect the remaining urethral calculi. The percentage and location of persistent calculi were recorded. The images were reconstructed using three kernels, from smooth to ultrasharp, and the calculi mHU were measured.

Results

Sixty-five patients were included in the study. The success rate of retrograde urohydropropulsion in the 45 male dogs was 55.6% and 86.7% at the first and second attempts, respectively. The predominant components of the calculi were cystine (20), struvite (15), calcium oxalate (8), and urate (7). The convolution kernel influenced the mHU values (p < 0.05). The difference in mHU regarding the calculus composition was better assessed using the smoother kernel. A mHU greater than 1,000 HU was predictive of calcium oxalate calculi.

Conclusions

Non-enhanced CT is useful for controlling the success of retrograde urohydropropulsion. The mHU could allow a prediction of the calculus composition, particularly for calcium oxalate, which may help determine the therapeutic strategy.

ACVIM Small Animal Consensus Recommendations on the Treatment and Prevention of Uroliths in Dogs and Cats

In an age of advancing endoscopic and lithotripsy technologies, the management of urolithiasis poses a unique opportunity to advance compassionate veterinary care, not only for patients with urolithiasis but for those with other urinary diseases as well. The following are consensus-derived, research and experience-supported, patient-centered recommendations for the treatment and prevention of uroliths in dogs and cats utilizing contemporary strategies. Ultimately, we hope that these recommendations will serve as a foundation for ongoing and future clinical research and inspiration for innovative problem solving.

Urethrotomy of the glans penis in three male dogs with urolithiasis

Three intact male dogs with stranguria and haematuria caused by uroliths in the penile urethra underwent urethrotomy using a novel surgical approach directly over the caudal part of the os penis because conservative procedures to resolve the obstructions had failed. Haemorrhage was minimal, and the incisions healed rapidly by second intention. Complications did not occur during the 6-month follow-up period. Urethrotomy directly over the os penis is straightforward, associated with few complications and holds promise for the removal of urinary calculi in the penile urethra.

Extraction of urethral calculi by transabdominal cystoscopy and urethroscopy in nine dogs

OBJECTIVES

To describe a minimally invasive technique for treating urethral obstructions in male dogs and to review the postoperative results.

METHODS

All dogs (n=9) had urethral obstruction due to calculi. Obstructions were verified by radiographic and ultrasonographic examinations. Dogs with impaired kidney function were not included in the study. A 5-mm diameter trocar and cannula were placed in the ventral midline, 2 cm cranial to the umbilicus, allowing placement of a 10-mm diameter cannula under visual guidance, adjacent to the apex of the bladder. The bladder was then partially exteriorised and sutured to the skin. A 5-mm diameter cystoscopy sheath was introduced into the bladder lumen and advanced into the urethra. Continuous retrograde flushing was used to dislodge the calculi from the site of obstruction and collect them upstream.

RESULTS

The nine dogs were followed up for a minimum of 6 months. No major postoperative complications were identified. One dog exhibited transient macroscopic haematuria (for 3 weeks postoperatively). All urethral calculi were removed in the nine dogs. No recurrence was found during the follow-up period.

CLINICAL SIGNIFICANCE

A minimally invasive approach is used to treat urethral obstructions resulting from calculi in the male dogs.

Changing paradigms in ethical issues and urolithiasis

This article defines the ethics involved in the medical treatment of patients. Using a case example, the authors discuss the treatment of uroliths from an ethical and medical perspective. Uroliths are defined, and treatment is discussed and explained.