Subcutaneous Ureteral Bypass Device Research Articles

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

BackgroundPlacement 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.ObjectivesTo characterize transmural migration of SUB devices within the digestive tract in cats.AnimalsEleven migrated SUB catheters identified in 8 cats between 2017 and 2021.MethodsRetrospective review of medical records of cats with a SUB device in which migration into the gastrointestinal tract was identified.ResultsThe 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 ImportanceAlthough a rare complication, migration of SUB device should be considered in cats with SUB device obstruction and a positive urine culture.

Use of tetrasodium EDTA acid for the treatment of intraluminal obstruction of subcutaneous ureteral bypass devices.

ObjectivesThe aim of this study was to evaluate the efficacy and tolerability of a 4% tetrasodium EDTA (tEDTA) infusion protocol in the subcutaneous ureteral bypass (SUB) devices of cats with intraluminal obstruction at a veterinary teaching hospital between July 2017 and April 2020.MethodsThis was a retrospective controlled study. Cats with an obstructed SUB device underwent a 4% tEDTA infusion protocol. Obstruction of the device was diagnosed based on renal pelvic dilation, dilatation of the ureter, mineralized material within the device (cystostomy or nephrostomy catheters) seen on ultrasound, the absence of visible bubbles within the renal pelvis and/or urinary bladder following ultrasound-guided flushing of the device with saline.ResultsA total of 16 tEDTA infusion protocols were performed in 14 cats. The infusion protocol was considered successful in 11/16 SUB devices (68.8%). Six devices (n = 6/11; 54.5%) had recurrence of obstruction with a median time of 87 days. One or more episodes of self-limiting pollakiuria and/or hematuria following infusion was seen in eight patients (n = 8/14; 57.1%).Conclusions and relevanceInfusions of 4% tEDTA successfully relieved intraluminal obstruction in patients with occluded SUB devices; however, the recurrence of obstruction was common. Additional studies evaluating case selection and optimal protocols are warranted.

Subcutaneous Ureteral Bypass Device for Treatment of Ureteral Obstruction in Persian Breed Female Cat

In the recent years, benign ureteral obstruction by nephrolithiasis has an increased incidence in the feline population, whose causes are not yet fully established. Its diagnosis is based on clinical signs, biochemical analyzes and imaging methods such as radiography and ultrasound. For its treatment, initially one can resort to pharmacological therapy. However, when this is ineffective or contraindicated due to the risk of deterioration of the renal condition, there is a need for surgical intervention. Currently, the subcutaneous ureteral bypass implantation technique is being used more frequently, despite the high cost and periodic mainitance of system functionally. In this case report, we describe the implantation of the subcutaneous ureteral bypass system in a 9-year-old Persian breed female cat with azotemia associated with total obstruction of the right ureter and partial obstruction of the left ureter by nephrolithiasis. In function of total obstruction of right ureter lumen and risk of total obstruction of left ureter lumen was decided by immediate surgery intervention with use of subcutaneous ureteral bypass system. After the implantation of the subcutaneous ureteral bypass system, there was disappearance of azotemia and improvement in the clinical picture and quality life of the cat female.

Subcutaneous ureteral bypass device placement in 81 cats with benign ureteral obstruction (2013-2018).

BackgroundBenign ureteral obstructions (BUOs) present a therapeutic challenge in cats.Hypothesis/ObjectivesThe purpose of this study was to determine the outcome and complications associated with placement of subcutaneous ureteral bypass (SUB) device in cats.AnimalsEighty‐one client‐owned cats (117 kidneys) with BUO treated by placement of a SUB.MethodsRetrospective study. Medical records of cats with BUO and treated by SUB device placement between 2013 and 2018 were reviewed. Outcome and complications were documented.ResultsHospital discharge rate was 94% (76/81). Serum creatinine on admission and at the time of discharge was 5.3 mg/dL (range, 1.2 to >15 mg/dL) and 2.1 mg/dL (range, 1.1‐12.5 mg/dL), respectively. Luminal obstructions were documented in 17% (18/109) of the SUB devices of 16 cats discharged from the hospital. Infection was documented in 26% (20/76) of discharged cats. Kink of the device was documented in 10% (12/117) of devices. Time to luminal obstruction and kink were 204 days (range, 21‐1678 days) and 58 days (range, 2‐601 days), respectively. Fourteen of 81 (17%) cats required a revision surgery in order to restore patency of the device. At the time of writing, 53% (43/81) of cats were alive, with a mean survival time of 821 days (range, 1‐2170 days) after surgery. Of those that died, 52% (20/38) died of urinary related causes.Conclusion and Clinical ImportanceThis study suggests that SUB device placement is associated with good outcomes and could be considered for the treatment of BUO in cats.

Cutaneous seeding of transitional cell carcinoma of the urinary bladder after placement of a subcutaneous ureteral bypass device in a dog with bilateral ureteral obstruction

A 12-year-old spayed female Jack Russell Terrier was presented with pollakiuria and stranguria. Transitional cell carcinoma (TCC) of the urinary bladder trigone and urethra was diagnosed via CT, cystoscopic, and histologic examinations. Azotemia developed 2 weeks following diagnosis, secondary to bilateral ureteral obstruction. Percutaneous antegrade ureteral stenting was unsuccessful; therefore, a subcutaneous ureteral bypass (SUB) device with 2 nephrostomy and 1 cystostomy catheters was surgically placed. Two months following placement of the SUB device, the dog developed a firm, multilobulated cutaneous mass at the site of the subcutaneous access port of the SUB device. Results of cytologic examination of cells aspirated from the mass were consistent with TCC. Within 1 month of confirmation of TCC of the cutaneous mass, the mass was ulcerated and infected, and the dog was euthanized because of signs of pain and perceived poor quality of life. Seeding of neoplastic cells is a known complication of needle aspiration or biopsy or surgery in people and dogs with carcinomas. The occurrence of TCC at the SUB port site suggested caution with the placement of a SUB device in dogs with obstructive TCC.

Subcutaneous ureteral bypass device placement with intraoperative ultrasound guidance, with or without microsurgical ureterotomy, in 24 cats.

The aim of this study was to describe a method of subcutaneous ureteral bypass (SUB) device placement with intraoperative ultrasound guidance, with or without microsurgical ureterotomy, for the treatment of benign ureteral obstruction(s) in cats. A secondary aim was to describe the complications and outcomes in our population, and compare the two groups with and without ureterotomy. The medical records of cats with benign ureteral obstruction(s) treated with SUB device placement with intraoperative ultrasound guidance between April 2013 and June 2018 were reviewed. Twenty-four cats with 30 obstructed ureters had a SUB device placement with intraoperative ultrasound guidance in 26 surgeries. A microsurgical ureterotomy was performed in 14/26 surgeries. Median age was 10.07 years (range 4-16.6). Eleven of 24 cats (46%) had a previous history of chronic kidney disease (CKD). All cats, including two patients with minimal pelvic dilation (⩽4 mm), had a successful intrapelvic placement of the SUB device. Median survival time was 1555 days (4.25 years); this was not significantly different between the two groups (P = 0.4494). Stone analysis and bacterial culture, where available for review, revealed calcium oxalate in 12/12 and a negative culture in 6/7. The ureterotomy significantly prolonged the procedure duration (180 vs 125 mins) without significantly decreasing the short- and long-term complications (P = 0.1588 and P = 0.2921, respectively), or the survival time (P = 0.8437). SUB device placement with intraoperative ultrasound guidance is an effective alternative for the treatment of ureteral obstruction. Ultrasound guidance may be a more accessible option when a trained veterinarian does not have access to fluoroscopy. Microsurgical ureterotomy did not show any advantage and prolonged the anesthesia. Our median survival time emphasizes a good outcome of SUB device placement, even in cats with a previous history of CKD.

Complications and survival after subcutaneous ureteral bypass device placement in 24 cats: a retrospective study (2016-2019).

The aim of this study was to document survival, complications and risk factors for the development of complications and mortality prior to discharge after placement of a subcutaneous ureteral bypass (SUB) device in cats. The medical records of cats with SUB placement between January 2016 and August 2019 were retrospectively analysed. The development of complications (overall, intraoperative, perioperative, short- and long-term complications) and risk factors for mortality prior to discharge were statistically assessed with univariate binary logistic regression. All variables with a P value ⩽0.10 in the univariate analysis were assessed in a multivariate model. Variables were significant if P <0.05. Twenty-four cats were included; 12 (50.0%) received a unilateral SUB, 11 (45.8%) a bilateral nephrostomy tube with single cystostomy catheter and the remaining cat (4.2%) two unilateral SUBs. Nearly 80% of the cats developed complications, ranging from mild to fatal, including (partial) SUB obstruction (33.3% of complications), lower urinary tract infection (20.8%), pyelonephritis (20.8%) and sterile cystitis (12.5%). Five cats (20.8%) died prior to discharge. Six cats (25.0%) underwent revision surgery. The overall median survival time (MST) was 274 days (range 1-311 days). Complications were most common in the long-term period (14/16 cats), followed by the short-term (9/18 cats), perioperative (10/23 cats) and intraoperative (4/24 cats) periods. Older cats had an increased risk for developing perioperative complications (P = 0.045) and were less likely to survive to discharge (P = 0.033). An increased haematocrit at presentation was a risk factor for the occurrence of short-term complications (P = 0.03). Although complications similar to those previously described were observed, the complication rate was higher and the MST shorter than previously reported in cats undergoing SUB placement. Despite good short-term survival, the development of complications may necessitate regular and intensive control visits. Owners that consider SUB placement should be informed that follow-up can be strenuous and expensive.

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

Case summaryA 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 informationTo 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.

Use of a subcutaneous ureteral bypass device for treatment of benign ureteral obstruction in cats: 174 ureters in 134 cats (2009-2015).

OBJECTIVE To determine outcomes of subcutaneous ureteral bypass (SUB) device placement for treatment of benign ureteral obstruction in cats. DESIGN Retrospective case series. ANIMALS 134 cats with SUB devices placed in 174 obstructed ureters during 144 hospitalizations. PROCEDURES Medical records of cats that underwent SUB device placement for treatment of benign ureteral obstruction between 2009 and 2015 were reviewed. The SUB device was placed by use of fluoroscopic and surgical methods. Signalment, history, diagnostic imaging results, postprocedural results, duration of hospitalization, complications, and short- and long-term outcomes were recorded. RESULTS Ureteral obstructions were caused by ureterolithiasis (114/174 [65.5%]), stricture (28/174 [16.1%]), both ureterolithiasis and stricture (29/174 [16.7%]), or pyonephrosis (1/174 [0.6%]); in 2 (1.1%) cats, the cause was not recorded. Fifty-two of the 134 (39%) cats had bilateral ureteral obstruction. At admission, 127 (95%) cats were azotemic. Median serum creatinine concentrations at admission and 3 months after SUB device placement were 6.6 and 2.6 mg/dL, respectively. Median renal pelvis diameters before and after the procedure were 9.2 and 1.5 mm, respectively. Postsurgical complications included device occlusion with blood clots (14/172 [8.1%]), device leakage (6/172 [3.5%]), and kinking of the device tubing (8/174 [4.6%]). Cats survived to hospital discharge after 135 of the 144 (94%) hospital admissions. The most common long-term complication was catheter mineralization (40/165 [24.2%]), which was documented a median of 463 days after device placement. A high postoperative serum ionized calcium concentration was significantly associated with SUB device occlusion. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that SUB device placement may be a viable option for treatment of cats with benign ureteral obstruction.

Treatment of ureterolithiasis in feline patients

Ureterolithiasis is becoming more frequently diagnosed in feline patients as diagnostic imaging has become more available and the understanding of the clinical signs suggestive of this disease process has grown. The presence of ureteral stones can be diagnosed by radiography and ultrasonography. As 98% of ureteral stones in cats are calcium oxalate, medical management may not be an option for the majority of cases. Subcutaneous ureteral bypass, nephroureterectomy, ureteral stenting and lithotripsy are all techniques that can be used for the treatment of ureteral obstruction caused by ureteral stones; this article focuses on the subcutaneous ureteral bypass device (SUB). This paper outlines how ureterolithiasis is diagnosed, briefly outlines treatment options then focuses on how the SUB device is placed. Postoperative care following a SUB placement is discussed as these patients need careful medical management in the immediate postoperative period to resolve azotaemia without causing fluid overload as well as lifelong follow-up care to ensure the SUB device stays patent and to support renal function.

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

This report describes a cat that presented with abdominal pain and worsening azotaemia following unknown trauma. Further diagnostic investigations and surgery confirmed bilateral ureteral trauma. The cat was initially managed surgically by bilateral ureteroureterostomy over ureteral stents. The clinical signs and biochemical parameters rapidly resolved, but 2 months later the cat developed signs consistent with sterile cystitis that was unresponsive to medical management. Removal of the ureteral stents resulted in severe azotaemia as a result of stricture formation at the previous ureteral anastomosis site. The ureteral stents were initially replaced with soft stents, but subsequently cut short owing to the persistence of clinical signs of cystitis. Following shortening of the ureteral stents severe azotaemia was again observed. The resulting pelvic dilatation allowed for placement of bilateral subcutaneous ureteral bypass (SUB) systems, which resulted in alleviation of all clinical signs 12 months after SUB placement.

Predictors of outcome for cats with ureteral obstructions after interventional management using ureteral stents or a subcutaneous ureteral bypass device

Novel treatment alternatives for feline ureteral obstruction(s) include placement of a double pigtail ureteral stent and a subcutaneous ureteral bypass (SUB) device. This study evaluated parameters for the prediction of hospitalization times, peri-operative survival, renal recovery and long-term survival in cats with benign ureteral obstructions after successful decompression with either a ureteral stent or SUB device. The medical records of 41 cats treated for benign ureteral obstruction(s) were retrospectively reviewed. Preoperative historical, biochemical and imaging parameters, along with intra- and postoperative biochemical parameters and complications were evaluated for predictors of hospitalization length, survival to discharge, 3-, 6- and 9-month post-procedure creatinine, and overall survival time. All patients had successful decompression of their renal pelvis. Hospitalization time was positively associated with presenting creatinine, perioperative complications, post-procedure creatinine and potassium, but was negatively associated with post-procedure sodium. No parameters were associated with survival to discharge. A higher creatinine at discharge was positively associated with a higher creatinine at follow-up. A decreased overall survival was associated with a higher presenting blood urea nitrogen, higher creatinine at hospital discharge and in over-hydrated patients during hospitalization. Cats with International Renal Interest Society stage 1 and 2 kidney disease, versus stage 3 and 4, at 3 months and 6 months post-procedure, lived longer. Cats with ureteral obstruction(s) treated with a ureteral stent or SUB device had an overall good survival and no admitting parameter was associated with survival to discharge. No single parameter was associated with all outcomes in this study, making predicting patient survival and cost prior to ureteral decompression difficult.