Efficacy and safety of laser lithotripsy in fragmentation of urocystoliths and urethroliths for removal in dogs

Nephrology in Veterinary Medicine

Veterinary nephrology is a specialized field of veterinary medicine providing a high level of care for animals with all types of kidney disease. Veterinarians complete extensive training to become board-certified in veterinary nephrology-urology. Companion animal nephrology is the most advanced field; however, all species are afflicted by a variety of renal disorders. Most naturally occurring animal kidney diseases have similar disorders found in people; where veterinary research is lacking, clinical management is often modified from standard of care in people. Veterinarians have become adept at scaling down procedures to safely perform them on dogs and cats weighing only a few kilograms. Advanced diagnostics (renal biopsy, cystoscopy, fluoroscopic studies, etc. ) and therapeutics (renal replacement therapy, interventional endourology, etc. ) are commonly performed within the practice of veterinary nephrology-urology. Collaboration between veterinary and human nephrologists may advance both disciplines and improve care for people and animals alike.

Comparison of percutaneous cystolithotomy and open cystotomy for removal of urethral and bladder uroliths in dogs: Retrospective study of 81 cases (2014-2018)

OBJECTIVE

Compare percutaneous cystolithotomy (PCCL) and open cystotomy (OC) for removal of bladder and urethral uroliths.

DESIGN

Retrospective study.

ANIMALS

Client-owned dogs and cats that underwent PCCL (n = 41) or OC (n = 40) between January 1, 2014 and February 28, 2018 at a referral center.

METHODS

Medical records of dogs and cats that underwent a PCCL or an OC were reviewed. History, signalment, physical examination, diagnostic tests, length of the procedure and anesthesia, complications, and duration of hospitalization were recorded.

RESULTS

A total 17 cats (PCCL = 10; OC = 7) and 64 dogs (PCCL = 31; OC = 33) were included. There was no significant difference, regardless of species, in the mean surgical time (45 min [24-160 min] and 48.5 min [15-122 min] with P = .54 in dogs, P = .65 in cats) nor mean duration of anesthesia (90 min [50-120 min] and 98 min [54-223 min] with P = .87 in dogs, P = .08 in cats) in the PCCL and OC groups respectively. Number of uroliths did not affect duration of surgery in either group. Complete urolith removal was achieved in 98% of dogs and cats in both groups. The median hospitalization time was significantly shorter in the PCCL group for dogs (11.3 hours [range 4 to 51.3] in the PCCL vs 56.6 hours [range 7.3 to 96] in the OC group; P < .001) but did not differ for cats (24.5 hours [range 8.3 to 30] in the PCCL vs 56.6 hours [range 10.1 to 193.2] in the OC group; P = .08).

CONCLUSION AND CLINICAL RELEVANCE

Bladder urolith removal by PCCL procedure is no longer than OC. Further studies are needed to compare the pain related to procedure between PCCL and OC.

Endoscopic-guided laser lithotripsy for removal of an encrusted ureteral stent in a dog

CASE DESCRIPTION

An 8-year-old spayed female Dalmatian was evaluated because of recurrent urinary tract infections following ureteral stent placement 3 years earlier.

CLINICAL FINDINGS

Polyuria, pollakiuria, and hematuria were reported by the owner. Abdominal radiography revealed well-defined, faintly mineralized material superimposed over the distal portion of the previously placed ureteral stent. Abdominal ultrasonography revealed thickening of the bladder wall, right hydroureter, and right pyelectasia; the ureteral stent appeared to extend into a region containing cystic calculi. Cystoscopy revealed small uroliths and mineralized encrustation of the distal portion of the ureteral stent.

TREATMENT AND OUTCOME

A holmium:yttrium-aluminum-garnet laser was used to fragment mineralized material from the distal end of the stent and allow endoscopic transurethral removal. Stone analysis revealed ammonium urate as the major component of the mineralized material. The owner was instructed to feed the dog a diet formulated to decrease the likelihood of urate stone recurrence and to administer marbofloxacin for 6 weeks because of suspected pyelonephritis. Follow-up bacterial culture of a urine sample and abdominal ultrasonography revealed resolution of urinary tract infection, pyelectasia, hydroureter, and associated clinical signs.

CLINICAL RELEVANCE

Results suggested that endoscopic-guided laser lithotripsy can be used as a minimally invasive alternative to surgery for removal of severely encrusted ureteral stents in dogs.

Radiographic features of suspected suture-associated cystic calculi in dogs

This retrospective case series describes the radiographic features of suspected suture-associated cystic calculi in six dogs with a history of at least one or multiple prior cystotomies. One of the dogs presented twice. Suspected suture-associated cystic calculi were multifocal, short, predominantly linear mineral opacities localized in the center of the urinary bladder on abdominal radiographs. One patient (n = 1) presented with multifocal round, pin point, and linear radiopaque calculi. The calculi were all calcium oxalate in composition. On gross examination, the calculi had a hollow center. Six cystotomies used monofilament absorbable suture material (polydioxanone [n = 4] or poliglecaprone 25 [n = 1]) in prior cystotomies. Suture material in two of the cases was unknown. Suspected suture-associated cystic calculi are a rare occurrence in veterinary medicine but should be considered in dogs that have a history of prior cystotomy, hollow core on gross analysis, and radiographic evidence of mineral opaque, predominantly linear, cystic calculi.

Transurethral cystoscopy in dogs with recurrent urinary tract infections: Retrospective study (2011-2018)

Background

Urinary tract infections (UTIs) are common in female dogs and recurrent infections often require investigation by transurethral cystoscopy.

Hypothesis/Objectives

Describe the findings of transurethral cystoscopy in dogs presented for recurrent urinary tract infections (RUTI).

Animals

Fifty‐three client‐owned dogs with RUTI were included in the study.

Methods

Retrospective study. Data collected from medical records included signalment, clinical findings, bladder wall culture, cystoscopic, and histopathologic findings. UTI was defined as: presence of compatible clinical signs and at least 2 out of 3 of the following criteria: (1) pyuria, (2) positive urine culture, (3) resolution of clinical signs with antibiotic treatment. Recurrence of UTI was defined as at least 2 episodes of UTI within 6 months or at least 3 or more in 1 year.

Results

The mean age at presentation was 3.8 years with a majority of female dogs (48/53), 40/48 of which were spayed. Main breeds were Labrador (10/53), Australian Shepherd (4/53), and Miniature Schnauzer (3/53). A hooded vulva was noted in 33/48 of females. Transurethral cystoscopy showed anomalies in 45/53 of cases: mucosal edema (19/53), vestibulovaginal septal remnant (15/48), lymphoid follicles (8/53), short urethra (6/53), and ectopic ureter (5/53). Urine culture at the time of cystoscopy was positive in 13/49. Bladder wall edema and ulceration were the most common findings on histopathology (25/39).

Conclusion and Clinical Importance

RUTI occurred more frequently in spayed female dogs. Transurethral cystoscopy is useful in the diagnosis and treatment of anomalies in dogs with RUTIs.

Technological Advances in Endoscopic Equipment in Exotic Pet Medicine

The aim of this article is to review some of the technological advances in endoscopy and endosurgery. The article focuses on a few key areas relevant to exotic pets, including advances in urolith management, visualization, and laparoscopic surgery.

Minimally Invasive Management of Uroliths in Cats and Dogs

Urolithiasis commonly affects cats and dogs. The American College of Veterinary Internal Medicine established guidelines for the treatment of uroliths that reflect modern techniques prioritizing minimally invasive procedures with an emphasis on prevention strategies to limit morbidity and mortality. Extracorporeal shockwave lithotripsy and endoscopic nephrolithotomy constitute some of the minimally invasive treatment modalities available for upper urinary tract uroliths. Cystoscopic-guided basket retrieval, cystoscopic-guided laser lithotripsy, and percutaneous cystolithotomy are minimally invasive options for the management of lower urinary tract uroliths. Following stone removal, prevention strategies are essential to help reduce morbidity and mortality associated with stone recurrence.

Feline Calcium Oxalate Urolithiasis: Risk factors and rational treatment approaches

PRACTICAL RELEVANCE

Uroliths occur commonly in the bladder and/or urethra of cats and can be lifethreatening if urethral obstruction occurs. Calcium oxalate accounts for 40-50% of urocystoliths and these stones are not amenable to medical dissolution; therefore, removal by surgery or minimally invasive techniques is required if uroliths must be treated. Medical protocols for prevention involve decreasing urine saturation for minerals that form uroliths.

ETIOPATHOGENESIS

Formation of uroliths is not a disease, but rather a complication of several disorders. Some disorders can be identified and corrected (such as infection-induced struvite urolith formation); others can be identified but not corrected (such as idiopathic hypercalcemia). In most cats with calcium oxalate urolith formation the underlying etiopathogenesis is not known. A common denominator of all these disorders is that they can from time to time create oversaturation of urine with one or more crystal precursors, resulting in formation of crystals.

BASIC CONCEPTS

In order to develop rational and effective approaches to treatment, abnormalities that promote urolith formation must be identified, with the goal of eliminating or modifying them. It is important, therefore, to understand several basic concepts associated with urolithiasis and the factors that promote urolith formation that may be modified with medical treatment; for example, the state of urinary saturation, modifiers of crystal formation, potential for multiple crystal types, and presence of bacterial infection or urinary obstruction.

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.

Cystoscopy in dogs and cats

Cystoscopy has become an important and widely available component of the diagnostic evaluation of diseases of the lower urinary tract in dogs and cats. In addition, a large number of cystoscopic guided procedures have been described that can be used to treat disease processes that were previously treatable only with invasive surgical procedures. This article reviews the indications and contraindications for cystoscopy, cystoscopy equipment and techniques for male and female dogs and cats, potential complications associated with cystoscopy, and management options for these complications.

Interventional urology: endourology in small animal veterinary medicine

The use of novel image-guided techniques in veterinary medicine has become more widespread, especially in urologic diseases. With the common incidence of urinary tract obstructions, stones disease, renal disease, and urothelial malignancies, combined with the recognized invasiveness and morbidity associated with traditional surgical techniques, the use of minimally invasive alternatives using interventional radiology and interventional endoscopy techniques has become incredibly appealing to owners and clinicians. This article provides a brief overview of some of the most common procedures done in endourology in veterinary medicine to date, providing as much evidence-based medicine as possible when comparing with traditional surgical alternatives.

Complications of lower urinary tract surgery in small animals

Surgical procedures of the lower urinary tract are commonly performed in small animal practice. Cystotomy for removal of uroliths and urethrostomy diverting urine outflow due to urethral obstruction are the most commonly performed surgical procedures of the bladder and urethra respectively. Surgical procedures of the lower urinary tract are typically associated with few complications, including leakage of urine, loss of luminal diameter (stricture or stenosis), urine outflow obstruction, tissue devitalization, denervation, urinary incontinence, urinary tract infection, and death. Complications can result from inappropriate or inadequate diagnosis, localization, and surgical planning; failure to respect regional anatomy, and other causes.

Diagnostic rigid endoscopy: otoscopy, rhinoscopy, and cystoscopy

Diagnostic examinations are markedly improved by using rigid endoscopy in the ear, nasal cavity, and urinary tract. This article presents the procedure, equipment, indications, and examples of abnormalities of rigid endoscopy in these areas. Textbooks, "hands-on" courses, and in-hospital training are methods for learning about these techniques and their applications. In addition to improving diagnostics, endoscopy can also be used for therapy in these three body areas.