Urodynamic effects of a percutaneously controlled static hydraulic urethral sphincter in canine cadavers

ACVIM consensus statement on diagnosis and management of urinary incontinence in dogs

Urinary incontinence (UI) is a disorder of micturition that can occur in dogs of any age, sex, and breed depending on the underlying cause and time of onset. Diagnosis and treatment for various causes of UI in dogs have been described by multiple comprehensive single author review articles, but large prospective clinical trials comparing treatment outcomes in veterinary medicine are lacking. The objectives of this consensus statement therefore are to provide guidelines on both recommended diagnostic testing and treatment for various causes of UI in dogs. Specifically, pathophysiology directly related to the canine urinary system will be reviewed and diagnostic and therapeutic challenges will be addressed. A panel of 12 experts in the field (8 small animal internists [L. Adams, J. Bartges, A. Berent, J. Byron, J. Foster, A. Kendall, S. Vaden, J. Westropp], 2 neurologists [J. Coates, N. Olby], 1 radiologist [G. Oetelaar], and 1 surgeon [C. Adin]) was formed to assess and summarize evidence in the peer-reviewed literature and to complement it with consensus recommendations using the Delphi method. Some statements were not voted on by all panelists. This consensus statement aims to provide guidance for management of both male and female dogs with underlying storage or voiding disorders resulting in UI.

Artificial urethral sphincter in male dogs with urethral sphincter mechanism incompetence: 19 cases (2010-2017)

OBJECTIVE

To assess the outcome and safety of surgically placed artificial urethral sphincters in male dogs with urethral sphincter mechanism incompetence.

MATERIALS AND METHODS

We included dogs with urethral sphincter mechanism incompetence treated by placing an artificial urethral sphincter from January 1, 2010 to December 31, 2017. The continence score (scale 1 to 5, with 5 indicating complete continence) was evaluated before and after implantation. Follow-up information was obtained from the institution's medical records (short-term up to 12 months) and questionnaires were completed by telephone (long-term ≥12 months) for evaluation.

RESULTS

Nineteen Medical therapy was unsuccessful in 18 dogs and unknown in one dog before the artificial urethral sphincter placement. Short-term continence improved in 16 of the 19 (84%) dogs. Four patients were lost to follow-up. Nine of 15 (60%) dogs showed long-term continence improvement, eight of 15 (53%) remained completely continent. The median follow-up was 1785 (range 2 to 3234) days. The complication rate was 56% (9/16). Minor complications, including haematoma, stranguria/temporary dyssynergia and mild inflammation at the port, were reported in four of 16 (25%) dogs. Five of 16 (31%) experienced major complications, including stranguria/mechanical urethral obstruction, persistent dyssynergia, fistula at the port and port rotation.

CLINICAL SIGNIFICANCE

Artificial urethral sphincter placement is a valid option for treating incontinent male dogs that show an insufficient response or become refractory to medical or other prior surgical management. A high-complication rate is associated with this procedure.

Canine urethral sphincter pressure profile under incremental inflation of an artificial cuff: a cadaver study

OBJECTIVES

To determine whether artificial urethral sphincter filling volume is proportional to peak pressure exerted on the urethra.

MATERIALS AND METHODS

Urethral pressure profilometry was performed in five female, medium-sized, mixed-breed canine cadavers following artificial urethral sphincter placement. Maximum urethral pressure was recorded following sequential incremental inflation of 0.15 mL and compared to baseline pressure and between dogs using two-way analysis of variance.

RESULTS

Artificial urethral sphincter placement in cadavers was associated with an increase in urethral pressure, which was significantly correlated with inflation volume. The correlation was non-linear and demonstrated considerable individual variation. Maximum urethral pressures after artificial urethral sphincter placement exceeded those reported in conscious continent dogs within a narrow volume range, in which a 0.15 mL infusion more than doubled maximal urethral pressures.

CLINICAL SIGNIFICANCE

Rapid increases in urethral pressure from the artificial urethral sphincter over a small range of filling volumes (0.15 mL increments) might explain why some clinical cases can become suddenly dysuric following incremental inflations. We suggest that smaller increments of filling (0.05 to 0.1 mL) may achieve finer pressure control.

Long-Term Outcome of Female Dogs Treated with Static Hydraulic Urethral Sphincter for Urethral Sphincter Mechanism Incompetence

The purpose of the study was to report the postoperative outcome, complications, and long-term follow-up of the use of a static hydraulic urethral sphincter for the management of urethral sphincter mechanism incompetence in female dogs. Medical records were reviewed to extract information on long-term (>365 days) outcome data. Telephone owner questionnaire was performed to assess postoperative urinary continence scores (scale 1–10, where 10 is complete continence) and the presence and frequency of complications. Twenty female dogs were included. Mean (±standard deviation) time to follow-up was 1,205.1 (±627.4) days. Median continence score/10 (range) was 3.5 (2–6) preoperatively, and 9.0 (7–10) at the last follow-up. Median continence score was significantly higher at all time points postoperatively compared with before surgery (P < .001). Complete continence was achieved in 90% of bitches. Minor complications occurred in 13 bitches and included dysuria (8), bacterial cystitis (8), longer urination time (10), incisional seroma (5), urinary retention (3), hematuria (2), and pain when urinating (2). Major complications occurred in one dog (static hydraulic urethral sphincter removed 28 mo after placement). Continence scores were sustainably improved in the long-term. Complications were mostly minor. Urinary tract infections were the most common but resolved with conventional antibiotic treatment.

Evaluation of percutaneously adjustable hydraulic urethral sphincters with and without induced mechanical failure

OBJECTIVE

To describe (1) the radiographic appearance of intact hydraulic urethral sphincters (HUS) and (2) the success of leak detection using clinically feasible methods.

STUDY DESIGN

Prospective, blinded in vitro study.

SAMPLE POPULATION

Thirty HUS devices (10 each of 8, 10, and 12 mm diameter sizes).

MATERIALS AND METHODS

All devices were inflated with saline (0.9% NaCl) solution to complete occlusion, inspected, and weighed over a 24-hour period for manufacturing defects. HUS phantoms were created to mimic surrounding soft tissues. One randomly selected HUS of each size was evaluated radiographically at different inflation volumes and angles. All HUS systems were then evaluated in random order before and after puncture with volumetry, manometry, radiography, and contrast fluoroscopy. Volumetry was the total volume (mL) retrieved from each HUS system. Manometry was the pressure (cm H2 O) within each HUS system. The HUS devices were filled to a known volume before each measurement.

RESULTS

When all HUS sizes were considered, volumetry did not reveal significant differences before and after puncture, but manometry was significantly different (P < .001). Radiography was 63.8% sensitive and 88.3% specific for puncture diagnosis, with inter-observer agreement of 0.58. Contrast fluoroscopy was 78.4% sensitive and 100% specific, with inter-observer agreement of 0.97.

CONCLUSIONS

Of those methods tested, contrast fluoroscopy was the most sensitive, specific, and consistent method of leak detection. Manometry was also helpful, but may be difficult to use clinically. Volumetry and radiography were relatively poor indicators of leakage in this model.

Retrospective evaluation of urethral bovine cross-linked collagen implantation for treatment of urinary incontinence in female dogs

BACKGROUND

Transurethral collagen injections are an alternative treatment for canine urinary incontinence. There is controversy regarding the long-term effectiveness of collagen and the impact urethral coaptation and injection site have on outcome.

HYPOTHESIS/OBJECTIVES

To evaluate outcome and client satisfaction after urethral collagen injections, and correlation between degree of urethral coaptation and collagen placement with outcome.

ANIMALS

Thirty-six procedures on 31 dogs, 10 with ureteral ectopia.

METHODS

Retrospective review of records and video evaluation of injection procedures. Follow-up communication with owners was performed between 1 and 56 months after bovine cross-linked collagen implantation to evaluate duration of continence, need for additional medical therapy, and owner satisfaction. Continence score was evaluated before and after the procedure, and after additional medical therapy, if needed. Injection location and degree of urethral coaptation was assessed with respect to duration of continence.

RESULTS

Dogs had a significant increase in continence score after the procedure. Mean (SD) duration of continence in dogs without addition of medication was 16.4 (15.2) months, and 5.2 (4.3) months in dogs needing additional medical therapy. No significant difference was found with respect to degree of coaptation. Median client satisfaction with the procedure was 100%.

CONCLUSIONS AND CLINICAL IMPORTANCE

Transurethral collagen implantation may be a viable option for treatment of female dogs with urethral sphincter mechanism incompetence, particularly after medical failure. Duration and degree of improvement are variable. Client satisfaction was excellent despite lack of complete continence in some dogs, and highlights the importance of discussing outcome expectations with owners.

Acquired urinary incontinence in the bitch: update and perspectives from human medicine. Part 3: The urethral component and surgical treatment

Urethral sphincter mechanism incompetence (USMI) is the most common cause of urinary incontinence in dogs. Surgery may be recommended if the animal does not respond to medical treatment or becomes refractory. In this third part of a three-part review, surgical options for the treatment of USMI are described. Colposuspension is the most frequently described procedure and offers a fair prognosis, with about 50% of the dogs being continent after surgery and most of the reminder being improved or more responsive to medical treatment. Urethropexy offers a similar success rate, but with a higher rate of complications. Endoscopic injection of collagen is an attractive technique due to its minimally invasive nature and low risk of adverse effects. Initial results may however deteriorate with time. Other procedures have been reported, but involve a low number of cases and have resulted in variable success rates. In women, stress urinary incontinence is mainly treated by minimally invasive procedures involving vaginal placement of sub-urethral slings.

Evaluation of manufacturing variability, diffusion of filling solutions, and long-term maintenance of occlusion in silicone hydraulic occluders

OBJECTIVE

To evaluate manufacturing variability, diffusion of filling solutions, and maintenance of occlusion over time in 3 sizes of silicone hydraulic occluders (HOs).

SAMPLE POPULATION

2-, 5-, and 20-mm HOs (HO2, HO5, and HO20, respectively).

PROCEDURES

Manufacturing variability was analyzed by comparing variation in internal luminal areas and filling volumes within each size group. Occluders were filled to 100% occlusion with air (n = 4), saline (0.9% NaCl) solution (4), or sodium hyaluronate (4) and submerged in simulated body fluid. Changes in luminal area and weight were recorded for 133 days to evaluate maintenance of occlusion.

RESULTS

Considerable variability in uninflated luminal area and fill volumes was observed among the 3 sizes of HOs. Loss of occlusion developed in the first 12 hours in all air-filled HOs. Fluid-filled occluders were reliable in maintenance of occlusion after 133 days (99.99% for HO20, 99.59% for HO5, and 90.40% for HO2), although diffusion of saline solution and hyaluronate from all HOs was confirmed by detection of significant decreases in weight over time. There was no significant difference in weight loss between HOs filled with saline solution and HOs filled with sodium hyaluronate.

CONCLUSIONS AND CLINICAL RELEVANCE

Saline solution or sodium hyaluronate may be used as a filling solution in the HOs tested. Maintenance of occlusion was best in the larger sizes. Saline solution or sodium hyaluronate should be used in future clinical investigations of HOs. Retrograde filling to remove air should be used when filling HOs with fluid.