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Objective: To evaluate outcome in 60 dogs with cystine urolithiasis treated with surgical removal with and without castration and postoperative therapeutic diet to determine frequency of recurrence and urolith-free duration., Methods: Patient records were reviewed for dogs with documented cystine urolithiasis from September 2010 to December 2020. Medical records, client interviews, and referring veterinarians were contacted to document the absence of clinical signs associated with subsequent urolith formation and to evaluate risk factors for urolith reoccurrence., Results: 80 patients were identified with cystine uroliths, with 60 qualifying for inclusion in the study. Seven dogs were neutered prior to surgery, and 25 dogs were neutered at the time of the first surgery. Recurrence occurred in 20 dogs; 17 of those patients were intact (85%) at the time of recurrent urinary signs. Of the 20 dogs with recurrence, 50% (10 of 20) were being treated with dietary modifications., Conclusions: The risk of recurrence among neutered pets was 23% versus 47% for intact pets, but this difference was not statistically significant; however, neutered pets had a longer urolithiasis-free duration. There was no statistically significant difference in risk of recurrence and urolith-free duration between pets with and without therapeutic diet management, (30% vs 32.5%) respectively. Multivariant analysis showed no significant interaction between surgical intervention with therapeutic diet, with nonsignificant hazard ratios (HRs) for neuter status (HR = 0.503), diet (HR = 1.056), and their interaction (HR = 4.32 to 9)., Clinical Relevance: Sexually intact (vs castrated) male dogs should be monitored more closely for recurrence of surgical cystine urolithiasis.

Objective: To describe the surgical technique and clinical outcome of small ruminants treated for obstructive urolithiasis using a modified tube cystostomy (MTC) technique., Animals: 15 goats and 2 sheep treated with an MTC between March 2018 and February 2023., Clinical Presentation: Animals were diagnosed with obstructive urolithiasis on the basis of history, physical examination, and ultrasonographic examination. An MTC was performed with sedation and a local block. Postoperative medical management was instituted to help reestablish urethral patency, and Foley catheters were removed after successful urination., Results: Animals were hospitalized an average of 3 nights (range, 0 to 14 nights). Complications included urine spillage in the abdomen and accidental deflation of the Foley balloon. Six animals were euthanized due to poor prognosis or failure to regain urethral patency. Foley catheters were removed an average of 15.7 days postoperatively in animals that regained urethral patency. Long-term (> 1-month) follow-up was available for 8 animals, with an average postoperative survival time of 19.4 months (range, 1 to 58 months). Four animals were lost to long-term follow-up., Clinical Relevance: This MTC technique is an effective means of catheterizing the urinary bladder in small ruminants. It can be performed under field conditions and serve as a standalone procedure for providing temporary urine egress. Patient size is limited by the length of the introducer, and an intact, distended urinary bladder and plan for reestablishing urethral patency are important considerations.

Objective: To assess the clinical outcome of a ferret undergoing a ureteroneocystostomy for treatment of urolithiasis., Animal: A 10-month-old spayed female ferret., Clinical Presentation, Progression, and Procedures: The ferret was evaluated for straining to urinate and defecate, hematochezia, and a rectal prolapse. Plain radiographs revealed large cystic and ureteral calculi. Clinicopathologic analyses indicated the ferret was anemic with an elevated creatinine concentration. Exploratory laparotomy defined bilateral ureteral calculi that were unable to be successfully moved into the bladder. A cystotomy was performed to remove a large cystic calculus. Serial abdominal ultrasonographic examinations showed progressive hydronephrosis of the left kidney and persistent pyelectasia of the right kidney secondary to bilateral ureteral calculi. This confirmed a left ureteral obstruction secondary to the distal calculus while the right ureter remained patent., Treatment and Outcome: A ureteroneocystostomy was performed to allow for left renal decompression. The ferret recovered well despite worsening hydronephrosis of the left kidney in the perioperative period. The ferret was discharged from the hospital 10 days after initial evaluation. At 3-week follow-up, abdominal ultrasonography confirmed resolution of hydronephrosis and ureteral dilation of the left kidney and ureter., Clinical Relevance: A ureteroneocystostomy successfully allowed renal decompression and ureteral patency in a ferret with urolithiasis. To the authors' knowledge, this is the first time this procedure has been reported in a ferret for treatment of a ureteral calculus obstruction and may result in good long-term outcome.

Objective: To report the presence of urolithiasis in dogs long-term after gradual attenuation of congenital extrahepatic portosystemic shunts (cEHPSS)., Animals: 25 client-owned dogs that underwent gradual attenuation of a cEHPSS, of which 19 had a closed cEHPSS and 6 developed multiple acquired portosystemic shunts (MAPSS) following surgery., Procedures: A retrospective study with prospective follow-up was performed. Dogs that underwent cEHPSS surgery and had their postoperative cEHPSS status determined by transsplenic portal scintigraphy or CT angiography 3 months postoperatively were prospectively contacted and invited for a long-term follow-up visit (a minimum of 6 months postoperatively). Retrospective data were collected, and during the prospective follow-up visit a thorough history, blood tests and urinalysis, and ultrasonography of the urinary tract were performed to assess the presence of urinary signs and urolithiasis., Results: Of 25 included dogs, 1 of 19 (5%) dogs with closed cEHPSS and 4 of 6 (67%) dogs with MAPSS had urolithiasis at long-term follow-up. Three (50%) dogs with MAPSS developed new uroliths. Long-term, dogs with closed cEHPSS that initially presented with and without urolithiasis had significantly less urolithiasis compared to dogs with MAPSS (P = .013 and P = .010, respectively). In the 4 dogs with closed cEHPSS that initially presented with nephrolithiasis, nephroliths became smaller or were no longer visible at the long-term follow-up visit., Clinical Relevance: Dogs that developed MAPSS following cEHPSS surgery are at greater risk of urolithiasis compared to those with closed cEHPSS. Furthermore, ammonium urate uroliths might dissolve if portosystemic shunting ceases to exist.

Urolithiasis is the most common cause of urinary tract disease in small ruminants and has significant economic and production impacts worldwide. Urolithiasis is multifactorial in origin and generally begins with the formation of cystoliths followed by urethral obstruction. The condition is most common in males. Clinical signs are variable depending on the severity of the obstruction. Uroliths can be calcium, struvite, or silicate based; however, struvite and amorphous magnesium calcium phosphate are the most common urolith types observed in small ruminants. Although urethral process (vermiform appendage) amputation is widely considered the first line of treatment, reobstruction is common within the first 36 hours. Surgical interventions such as temporary tube cystostomy, perineal urethrostomy (PU), modified proximal perineal urethrostomy, vesico-preputial anastomosis (VPA), and urinary bladder marsupialization (BM) are reported to carry an improved prognosis for long-term survival. PU carries a lower proportion of long-term success (> 12-month survival time) when compared with VPA and BM. Stoma stricture and urine scald are the most commonly observed surgical complications. Currently, the literature provides minimal direction for clinician decision-making in managing these cases while accounting for patient history, client financial ability, composition of calculi, and potential treatment complications. Small ruminant urinary obstructions are challenging and complicated conditions to treat, due to their multifactorial etiology, ruminant urogenital anatomy, and the variety of imperfect treatment options available. The purpose of this article this article is to provide veterinary practitioners with decision trees to guide management and treatment of urolithiasis in small ruminants.

Case Description: A 6-year-old castrated male Bactrian camel was evaluated because of a 14hour history of oliguria and stranguria that progressed to anuria., Clinical Findings: Perineal urethral pulsations and intermittent tail flagging with no accompanying urination were observed. Ultrasonography of the urethra revealed multiple hyperechoic foci with shadowing artifact indicative of calculi present in the penile urethra distal to the sigmoid flexure. Rectal palpation revealed a pulsating hard urethra and intact distended urinary bladder. Further clinical examination was not possible because of challenges associated with handling the camel., Treatment and Outcome: Urethral catheterization through a perineal urethral incision failed to achieve urinary bladder decompression. Tube cystostomy was performed to prevent bladder rupture. Urethrocystography performed 3 days after surgery revealed a urethral rupture at the level of the prepuce. Five weeks after surgery, the camel could urinate a steady stream via the urethrotomy site. Seven weeks after surgery, the cystostomy tube was removed, and the urethrotomy site was modified to provide a permanent urethral opening via perineal urethrostomy. During 6 years of subsequent periodic follow-up by telephone, the owner reported that the camel continued to do well and urinate through the revised opening., Clinical Relevance: To the authors' knowledge, this is the first detailed description of a tube cystostomy in an adult camel with obstructive urolithiasis that includes information on the patient's long-term outcome. This technique was a viable option in the surgical management of obstructive urolithiasis in this camel and may be useful for other large camelids as well.

OBJECTIVE To describe the ultrasonographic appearance of the urinary bladder incision site in dogs that underwent cystotomy for treatment of urolithiasis. DESIGN Prospective, longitudinal study. ANIMALS 18 client-owned dogs. PROCEDURES Dogs underwent urinary bladder ultrasonography at baseline (≤ 1 day before surgery) and at 1 day and approximately 2, 6, and 12 weeks after cystotomy for urocystolith removal. A baseline ratio between ventral (cystotomy site) and corresponding dorsal midline wall thickness was calculated and used to account for measurement variations attributable to bladder distension at subsequent visits. Patient signalment, weight, medications administered, urocystolith composition, and culture results were recorded. Clinical signs, reoccurrence of hyperechoic foci, and suture visualization were recorded at follow-up examinations. Variables were evaluated for association with cystotomy site thickening and resolution of thickening. RESULTS Median wall thickness at the ventral aspect of the bladder was significantly greater than that of the corresponding dorsal aspect at baseline. Cystotomy site thickening peaked 1 day after surgery and decreased at subsequent visits in a linear manner. Twelve weeks after surgery, 5 of 10 clinically normal dogs evaluated had persistent cystotomy site thickening. Eleven of 18 dogs had reoccurrence of hyperechoic foci within the bladder at some time during the study (median time to first detection, 17 days after surgery). CONCLUSIONS AND CLINICAL RELEVANCE Persistent cystotomy site thickening can be present up to 3 months after cystotomy for urolithiasis in dogs without lower urinary tract signs. Reoccurrence of hyperechoic foci in the bladder, although subclinical, was detected earlier and at a higher rate than anticipated.

CASE DESCRIPTION A 5-year-old sexually intact female guinea pig was evaluated because of mild dysuria and a subcutaneous mass located cranioventral to the urogenital openings. CLINICAL FINDINGS Non-contrast-enhanced CT and surgical exploration of the distal aspect of the urethra revealed a urethral diverticulum with an intraluminal urolith. Analysis revealed that the urolith was composed of calcium carbonate and struvite. TREATMENT AND OUTCOME The urolith was surgically removed and ablation of the urethral diverticulum was attempted. Approximately 3 months later, the guinea pig was reevaluated for masses in the perineal region, and positive-contrast urethrocystography revealed 2 uroliths present in the same diverticulum. Uroliths were manually expressed with the patient under general anesthesia. Approximately 2 weeks later, urethroplasty was performed to create an enlarged stoma with the diverticulum, thereby preventing urine from pooling in the diverticulum and potentially reducing the risk of future urolith formation. The urethroplasty site healed well with no reported complications or evidence of urolith recurrence 6 months after surgery. CLINICAL RELEVANCE Urolithiasis is common in guinea pigs, and urethral diverticulum and intraluminal urolith formation should be considered as a potential differential diagnosis for a subcutaneous mass along the distal aspect of the urethra. Creation of a urethral stoma from a urethral diverticulum via urethroplasty achieved a successful outcome in this patient.

Case Description: An 11-year-old Arabian gelding was evaluated for hematuria, stranguria, and pollakiuria that had been observed for 1 week., Clinical Findings: Transrectal palpation revealed a 5-cm firm round mass in the urinary bladder. Cystoscopy and transrectal ultrasonography confirmed the diagnosis of urinary bladder urolithiasis., Treatment and Outcome: A multiportal transparalumbar fossa laparoscopic approach was selected for cystotomy and urolith removal. Cystotomy and urolith removal was performed with sedation and local anesthesia with the horse standing. No perioperative complications were observed. Urination returned to normal 5 days after surgery. The horse returned to its previous level of activity at 3 weeks after surgery., Clinical Relevance: Findings suggested that minimally invasive transparalumbar fossa laparoscopic approach can be successfully used for cystotomy and urolith extraction in standing horses; this avoids the disadvantages of conventional laparocystotomy for removal of large uroliths in male equids and the potential complications of general anesthesia and recovery. The technique provided excellent viewing and access to the bladder, permitting extraction of the urolith and secure closure of the cystotomy with minimal tension and tissue trauma to the bladder.

Objective: To compare efficacy, required resources, and perioperative complications between laser lithotripsy and cystotomy for urolith (ie, urocystoliths and urethroliths) removal in dogs., Design: Retrospective case-control study., Animals: 66 dogs with urolithiasis treated by laser lithotripsy (case dogs) and 66 dogs with urolithiasis treated by cystotomy (control dogs)., Procedures: Medical records were reviewed. Complete urolith removal rate, resources (ie, duration of hospitalization, procedure time, anesthesia time, procedure cost, and anesthesia cost), and complications (ie, hypotension, hypothermia, incomplete urolith removal, and requirement of an ancillary procedure) were compared between cystotomy group dogs and lithotripsy group dogs., Results: Duration of hospitalization was significantly shorter for lithotripsy group dogs, compared with cystotomy group dogs. Procedure time was significantly shorter for cystotomy group dogs, compared with lithotripsy group dogs. Cost of anesthesia was significantly less for cystotomy group dogs, compared with lithotripsy group dogs. No significant differences were found between cystotomy group dogs and lithotripsy group dogs with regard to urolith removal rate, procedure cost, anesthesia time, or any of the evaluated complications., Conclusions and Clinical Relevance: Laser lithotripsy is a minimally invasive procedure that has been shown to be safe and effective in the removal of urocystoliths and urethroliths in dogs. No significant differences were found in the required resources or complications associated with laser lithotripsy, compared with cystotomy, for removal of uroliths from the lower portions of the urinary tract of dogs. Laser lithotripsy is a suitable, minimally invasive alternative to surgical removal of urethroliths and urocystoliths in dogs.

Case Description: An 11-month-old female dog was evaluated because of a 3- to 4-day history of stranguria and hematuria., Clinical Findings: Rectal and vaginal examination and abdominal radiography revealed a large (4 x 2 cm), firm, ovoid object in the area of the pelvic inlet, between the vagina and colon., Treatment and Outcome: Surgical exploration revealed an abscess and moderate amount of seropurulent fluid in the left caudal abdominal quadrant. A large urethrolith (3.7 x 2.0 x 1.5 cm) was evident in the proximal portion of the urethra. The urethrolith was associated with a 3 x 1-cm area of necrosis in the ventral aspect of the proximal portion of the urethra and a 3 x 3-cm area of necrosis in the area of the bladder trigone. The necrotic areas were débrided, and the defect was repaired with an axial pattern flap constructed from the rectus abdominis muscle. During a follow-up examination 2.5 years after surgery, the dog was clinically normal with no history of urinary incontinence. During rigid cystoscopy, the ure-thral mucosa appeared grossly normal, and there was no evidence of stricture., Clinical Relevance: Findings suggested that axial pattern flaps constructed from the rectus abdominis muscle flap may be useful in reconstructing large urinary bladder and urethral defects.

Objective: To determine trends in urolith composition in cats., Design: Retrospective case series., Sample Population: 5,230 uroliths., Procedures: The laboratory database for the Gerald V. Ling Urinary Stone Analysis Laboratory was searched for all urolith submissions from cats from 1985 through 2004. Submission forms were reviewed, and each cat's age, sex, breed, and stone location were recorded., Results: Minerals identified included struvite, calcium oxalate, urates, dried solidified blood, apatite, brushite, cystine, silica, potassium magnesium pyrophosphate, xanthine, and newberyite. During the past 20 years, the ratio of calcium oxalate stones to struvite stones increased significantly. When only the last 3 years of the study period were included, the percentage of struvite stones (44%) was higher than the percentage of calcium oxa-late stones (40%). The most common location for both types of uroliths was the bladder. The number of calcium oxalate-containing calculi in the upper portion of the urinary tract increased significantly during the study period. The number of apatite uroliths declined significantly and that of dried solidified blood stones increased significantly, compared with all other stone types. No significant difference in the number of urate stones was detected., Conclusions and Clinical Relevance: The increasing proportion of calcium oxalate uroliths was in accordance with findings from other studies and could be a result of alterations in cats' diets. However, the decreased percentage of calcium oxalate calculi and increased percentage of struvite calculi observed in the last 3 years may portend a change in the frequency of this type of urolith.