Management of bilateral ureteral trauma using ureteral stents and subsequent subcutaneous ureteral bypass devices in a cat

Antimicrobial and Antiproliferative Coatings for Stents in Veterinary Medicine-State of the Art and Perspectives

Microbial colonization in veterinary stents poses a significant and concerning issue in veterinary medicine. Over time, these pathogens, particularly bacteria, can colonize the stent surfaces, leading to various complications. Two weeks following the stent insertion procedure, the colonization becomes observable, with the aggressiveness of bacterial growth directly correlating with the duration of stent placement. Such microbial colonization can result in infections and inflammations, compromising the stent's efficacy and, subsequently, the animal patient's overall well-being. Managing and mitigating the impact of these pathogens on veterinary stents is a crucial challenge that veterinarians and researchers are actively addressing to ensure the successful treatment and recovery of their animal patients. In addition, irritation of the tissue in the form of an inserted stent can lead to overgrowth of granulation tissue, leading to the closure of the stent lumen, as is most often the case in the trachea. Such serious complications after stent placement require improvements in the procedures used to date. In this review, antibacterial or antibiofilm strategies for several stents used in veterinary medicine have been discussed based on the current literature and the perspectives have been drawn. Various coating strategies such as coating with hydrogel, antibiotic, or other antimicrobial agents have been reviewed.

Feline ureteral rupture with para-ureteral urinomas following blunt trauma: clinical presentation and long-term outcome after treatment by urinary diversion for five cases from 2012 to 2019

CASE HISTORY

Medical records were reviewed for cats that underwent surgical treatment of traumatic ureteral rupture (TUR) using urinary diversion procedures between 2012 and 2019.

CLINICAL FINDINGS AND TREATMENT

Five cats had presented with injuries associated with road traffic accidents. These included three cats with abdominal hernias that required surgical management. At a median of 15 days after the accident, cats represented with lethargy, the presence of an abdominal mass or with lower urinary tract symptoms and in all cats contrast diagnostic imaging showed proximal unilateral TUR with associated para-ureteral urinoma. Four cats received subcutaneous ureteral bypass (SUB) device placement and one had ureteral anastomosis over a stent. Unilateral cyst-like retroperitoneal fluid consistent with para-ureteral urinoma was observed in all cats and a diffuse retroperitoneal haematoma was noticed in four cats. No immediate major complications occurred, and all cats had post-operative serum creatinine concentration within the reference interval. The cat that had received a ureteral stent subsequently required placement of a SUB following stent encrustation 15 months after surgery. Median follow-up time was 34 (min 28, max 58) months and renal function was normal in all cats at the last follow-up.

CLINICAL RELEVANCE

Urinary diversion procedures provided long-term stable renal function following proximal TUR in these five cats. Delayed, subtle non-specific clinical signs subsequent to high-energy blunt trauma causing abdominal hernia and associated diffuse retroperitoneal haematoma, should raise suspicion of TUR.

ABBREVIATIONS

AFAST: Abdominal focused assessment with sonography for trauma; SUB: Subcutaneous ureteral bypass; TUR: Traumatic ureteral rupture.

Urinary Tract Trauma in Cats: Stabilisation, Diagnosis and Management

PRACTICAL RELEVANCE

Traumatic injury of the urinary tract may be caused by external accidental trauma or due to iatrogenic injury (typically as a result of catheterisation procedures). Thorough patient assessment and careful attention to patient stabilisation are essential, with diagnosis and surgical repair delayed until the patient is stable, if necessary. Treatment depends on the location and severity of the trauma. If diagnosed and treated promptly, the chance of survival of a patient without other concurrent injuries is good.

CLINICAL CHALLENGES

Following accidental trauma, at the initial presentation urinary tract injury can be overshadowed by other injuries, but if left undiagnosed or untreated it can lead to serious morbidity and potentially mortality. Many of the surgical techniques described for management of urinary tract trauma can be associated with complications, and so comprehensive communication with the owners is necessary.

PATIENT GROUP

The main population affected by urinary tract trauma is young, adult male cats, owing to their roaming behaviour, as well as their anatomy and the resulting increased risk of urethral obstruction and its associated management.

AIMS

This article aims to serve as a guide to all veterinarians who treat cats for the diagnosis and management of urinary tract trauma in cats.

EVIDENCE BASE

This review summarises the current knowledge available from a number of original articles and textbook chapters in the literature that cover all aspects of feline urinary tract trauma, and is supported by the authors' own clinical experience.

Stents in Veterinary Medicine

Stenting in veterinary medicine has been a rapidly growing method of interventional surgery for several years. This procedure is usually performed in the respiratory and urinary tracts, but there are cases of stenting of blood vessels or gastrointestinal structures. It is based on maintaining the permeability of a given tubular structure, thus allowing the passage of gas or liquid. This procedure is often performed as a first-line treatment in situations where pharmacological agents do not work and as an alternative method, often cheaper than the classically performed ones. There are also cases where stenting is used as a palliative treatment, e.g., to enable defecation in colonic obstruction due to tumour infiltration of the colon wall. Stenting is often a life-saving or comfort-improving procedure for animals, but one should also be aware of possible postoperative complications and be prepared for any adversity. For this reason, this review provides an insight into the current knowledge in veterinary medicine about stenting and the consequences associated with this procedure.

Multicenter retrospective evaluation of transmural migration of subcutaneous ureteral bypass devices within the digestive tract in catsone

BACKGROUND

Placement of a subcutaneous ureteral bypass (SUB) device is an effective method to relieve all causes of ureteral obstruction in cats. Complications involving migration within the gastrointestinal tract have been seldomly described.

OBJECTIVES

To characterize transmural migration of SUB devices within the digestive tract in cats.

ANIMALS

Eleven migrated SUB catheters identified in 8 cats between 2017 and 2021.

METHODS

Retrospective review of medical records of cats with a SUB device in which migration into the gastrointestinal tract was identified.

RESULTS

The median time from SUB device placement to implant migration was 928 days (201-2298 days). Seven cats had obstruction of the SUB device and a positive urine culture at diagnosis. The migration was identified by ultrasound in 6/11, pre-operative contrast radiography in 2/2, and only at time of surgery in 3 SUB devices. All cats underwent surgical correction. Four nephrostomy and 7 cystotomy catheters migrated. Migration occurred into the duodenum (3/11), jejunum (7/11), and colon (1/11). SUB devices were removed in 7 cats and replaced in 2 cats, with 1 cat diagnosed with 2 migration events. Gastrointestinal resection and anastomosis were performed in 7/8 cats and an enterotomy in 2 cats. Six cats survived to discharge. The median follow-up time after migration diagnosis was 365 days (range, 0-1114 days) and 2 cats are still alive.

CONCLUSIONS AND CLINICAL IMPORTANCE

Although a rare complication, migration of SUB device should be considered in cats with SUB device obstruction and a positive urine culture.

Renal pelvic rupture, intrapelvic haematoma and retroperitoneal haemorrhage associated with obstructive ureterolithiasis in a cat

A neutered female cat presented with a 9-day history of hyporexia and depression. The referring veterinarian had identified moderate non-regenerative anaemia, haematuria and suspected unilateral obstructive ureterolithiasis. Subsequent ultrasonography revealed moderate distension of the left renal pelvis with echogenic material, ureteral distension and ureterolithiasis. A partial ureteral obstruction was suspected. After 4 days of medical management, there was further distension of the renal pelvis with well-delineated echogenic material and an accumulation of perinephric fluid. A left nephroureterectomy was performed. Renal pelvic rupture with intrapelvic haematoma and retroperitoneal haemorrhage was confirmed by histopathology. Eighteen months following surgery, the cat remained clinically well with normal renal values.

Placement of ureteral stents in three rabbits for the treatment of obstructive ureterolithiasis

Management of ureteral obstruction with stenting is often associated with a lower rate of complications than ureterotomy in domestic carnivores, but this treatment has not been previously evaluated in rabbits. Three rabbits (7, 6 and 10 years old) were diagnosed with unilateral obstructive ureterolithiasis associated with hydronephrosis and hydroureter on abdominal ultrasound. Decreased overall renal function was confirmed in all three cases. Ureteral stents were placed retrogradely via cystotomy without complication in two cases and anterogradely via nephrostomy in the third case. Survival after stent placement was 30, 3 and 8 months, with encrustation of the stent and re-obstruction occurring 18, 1 and 6 months after stent placement in successive cases. Ureteral stenting can be considered for short-term management of ureterolithiasis in rabbits to improve renal function and maintain quality of life. Ultrasound or radiographic monitoring is recommended to detect encrustation of the stent. Studies comparing ureteral stenting to ureterotomy in rabbits are needed to determine the effectiveness of these techniques.

Use of a subcutaneous ureteral bypass device for treatment of bilateral proximal ureteral injury in a 9-month-old cat

Case summary

A 9-month-old male domestic longhair cat presented following iatrogenic ureteral trauma after an attempted laparoscopic ovariectomy. Prior to identifying that the cat was male, both ureters were transected approximately 4 mm from the renal pelves. Initial management involved a left-sided Boari flap neoureterocystostomy, cystonephropexy and right ureteronephrectomy. Thirty-six hours later, the cat developed uroabdomen due to leakage from the neoureterocystostomy site. At a tertiary referral institution, the ureter was reconstructed via end-to-end anastomosis and a left-sided subcutaneous ureteral bypass (SUB) device was placed in the event the anastomosis failed. Five weeks after SUB placement, the cat was dysuric and stranguric. A urine culture was negative and clinical signs were attributed to sterile cystitis secondary to device placement. Blood urea nitrogen (BUN) was 22 mg/dl and creatinine was 1.2 mg/dl. Contrast pyelography confirmed device patency, but no contrast was identified through the ureteral anastomosis. At 12 months, BUN and creatinine were 1.5 mg/dl and 25 mg/dl, respectively, and a subclinical urinary tract infection was identified (Enterococcus faecalis). Antibiotic therapy was not prescribed in order to prevent multidrug resistance. At 42 months, BUN was 38 mg/dl and creatinine was 2.0 mg/dl. The cat had occasional and intermittent signs of pollakiuria and stranguria but was otherwise doing well.

Relevance and novel information

To our knowledge, this is the first case report to describe the use of a SUB device for management of traumatic proximal ureteral injury in a cat with one kidney. The case outcome provides valuable information about the direct effect of the SUB device and the presence of chronic Enterococcus species infection on long-term renal function.

Interventional Radiology and Interventional Endoscopy in Treatment of Nephroureteral Disease in the Dog and Cat

Interventional endoscopy and interventional radiology have led to the development of minimally invasive techniques for management of kidney and ureteral diseases in the dog and cat including idiopathic renal hematuria, ureteral obstruction, and ectopic ureters. Sclerotherapy is a renal-sparing chemical cauterization technique used in cases of idiopathic renal hematuria. Diagnosis of ureteral obstruction is challenging in some cases based on ultrasound alone and antegrade pyelography should be considered. Treatment options for obstructions include nephrostomy tubes, ureteral stents, and subcutaneous ureteral bypass devices. Treatment with cystoscopic-guided laser ablation provides similar outcomes to surgery in dogs with intramural ectopic ureters.

Use of a Boari flap and renal descensus as treatment for proximal ureteral rupture in a cat

CASE DESCRIPTION A 6-year-old neutered male domestic shorthair cat was evaluated because of signs of abdominal pain and anuria of 12 hours' duration after vehicular trauma. CLINICAL FINDINGS Lethargy, mydriasis, bradycardia, abdominal distension, and signs of pain on abdominal palpation were observed. Abdominal ultrasonography revealed moderate urinary bladder distension without evidence of free abdominal fluid; hematologic evaluation revealed leukocytosis with high BUN and serum creatinine concentrations. TREATMENT AND OUTCOME The patient was hospitalized, medical stabilization was attempted, and an indwelling urinary catheter was placed. Urinary output was < 1 mL/kg/h (< 0.45 mL/lb/h), and signs of abdominal pain persisted despite treatment. The next day, ultrasonographic examination revealed fluid in the retroperitoneal space, and ureteral rupture was suspected. Exploratory laparotomy confirmed retroperitoneal fluid accumulation; a large hematoma surrounded the right kidney and perirenal structures. An abdominal drain was placed to aid patient stabilization. Three days later, IV pyelography revealed rupture of the proximal part of the right ureter. Ureteroneocystostomy was performed with elongated cystoplasty through a Boari flap and caudal transposition of the right kidney (renal descensus). On follow-up examination 18 months after treatment, the cat was free of clinical signs, and results of ultrasonography, CBC, and serum biochemical analysis were unremarkable. CLINICAL RELEVANCE Results suggested that a Boari flap procedure with renal descensus could be a feasible alternative in the management of proximal ureteral rupture in cats, but research is needed in this area.

[Subcutaneous ureteral bypass devices as a treatment option for bilateral ureteral obstruction in a cat with ureterolithiasis]

A 6-year-old female spayed Domestic Shorthair cat was presented with acute lethargy, dehydration, marked azotemia, metabolic acidosis, left-sided renomegaly, and bilateral hydronephrosis. Ureterolithiasis and ureteral obstruction were suspected based on further diagnostics including abdominal sonography. Medical treatment was not successful. Fluoroscopically guided antegrade pyelography confirmed the diagnosis of bilateral ureteral obstruction due to ureterolithiasis. Subcutaneous ureteral bypass (SUB) devices were placed bilaterally, followed by close patient monitoring. Frequent reassessment of patient parameters and blood work served to adjust the fluid needs of the patient and to ensure proper hydration, correction of azotemia at an appropriate rate, and cardiovascular stability. After significant improvement of all patient parameters within 5 days, the patient was discharged from the hospital. Treatment included a dietary change to reduce the risk of stone formation as well as a phosphorus binder. Clinical and clinicopathologic parameters were unchanged at the 1- and 4- and 7-month rechecks (consistent with IRIS CKD stage II-NP-AP0), and both SUB devices continued to provide unobstructed urine flow. Bilateral placement of subcutaneous ureteral bypass devices may be a safe and potentially effective treatment option for acute bilateral ureteral obstruction in cats with ureterolithiasis. Strict patient monitoring and patient-centered postoperative treatment decisions are crucial to successful treatment outcomes.

Feline double pigtail ureteric stents for management of ureteric obstruction: short- and long-term follow-up of 26 cats

The objective of this study was to determine the outcome of cats with ureteric obstruction managed with double pigtail ureteric stents and to document the incidence of lower urinary tract signs at long-term follow-up. Data were obtained retrospectively from the medical records (2009-2012) of 26 cats that underwent ureteric stent placement. Owners were contacted for follow-up, and a quality of life questionnaire completed. Survival to discharge after stent placement was 85% (22/26). Prevalence of postoperative uroabdomen necessitating further surgery was 15% (4/26). Stents were replaced 4-28 months after the initial surgery in four cats because of migration, fracture, encrustation causing luminal obstruction or sterile cystitis, respectively. Nine cats were alive at follow-up, which was 3-28 months after the original surgery. Nine cats had azotaemic chronic kidney disease and nine had signs related to sterile cystitis; three of these cats were euthanased as a result of the severity of the signs. Preoperative serum creatinine of the survivors (9.4 mg/dl, n = 9) was not significantly different from that of the non-survivors (6.5 mg/dl, n = 13; P = 0.295). Quality of life was assigned a mean score of 8/10. Median survival of cats following discharge was 419 days (range 44-994 days). Signs consistent with sterile cystitis affected 35% of cats. It was concluded that ureteric stent placement in cats was associated with a 15% mortality rate before hospital discharge. Long-term management of ureteric stents is associated with a high rate of lower urinary tract signs.