Preservation of striated-muscle urethral sphincter function with use of a surgical technique for perineal urethrostomy in cats

It has been reported that perineal urethrostomy resulted in impairment of striated-muscle urethral sphincter function in male cats, as measured by urethral pressure profilometry and electromyography (EMG). Our study was undertaken to describe and evaluate a surgical technique for perineal urethrostomy that reduces trauma to the urethral branches of the pudendal nerve. Perineal urethrostomy was performed on 10 healthy neutered cats after demonstrating that they had normal urethral sphincter function by urethral pressure profilometry (maximal urethral closure pressure [MUCP] = 151 +/- 52 cm of water) and EMG activity at the level of the striated-muscle sphincter before surgery. All cats had normal urethral sphincter function 1 week (MUCP = 194 +/- 19 cm of water, EMG activity present) and 3 weeks (MUCP greater than 200 cm of water, EMG activity present) after surgery. These results indicated that preservation of the urethral branches of the pudendal nerve during urethrostomy preserved striated-muscle urethral sphincter function.     

Clinical response and urethral pressure profile changes after phenylpropanolamine in dogs with primary sphincter incompetence

Based on clinical response, urethral pressure profile changes, and lack of side effects, phenylpropanolamine was effective and safe in treating dogs with primary sphincter incompetence. Primary sphincter incompetence was diagnosed in 11 female and 8 male dogs with urinary incontinence. Urodynamics of the dogs were assessed, using a combined urethral pressure profile and urethral sphincter electromyography. Male and female dogs had significantly (P less than 0.05) lower maximal urethral closure pressures, when compared with clinically normally dogs (36.91 +/- 8.20 cm of H2O vs 79.72 +/- 4.61 cm of H2O for female dogs and 48.63 +/- 8.68 cm of H2O vs 99.77 +/- 11.71 cm of H2O for male dogs). After treatment with phenylpropanolamine, there was a significant increase in maximal urethral closure pressure in both sexes to within normal range (77.73 +/- 8.70 cm of H2O in females and 92.50 +/- 14.60 cm of H2O in males). Electromyographic activity was normal before and after treatment. Urinary incontinence resolved clinically in all but 1 male and 1 female dog; however, the condition in these 2 dogs improved considerably. Minimal side effects were seen clinically. Mean arterial blood pressure was not altered by treatment. Plasma estrogen and testosterone concentrations in 8 female dogs were not different from those in continent female dogs. The incontinence in these dogs was considered a sphincter incompetence rather than estrogen responsive.     

Use of fine-wire electrodes for electromyographic evaluation of the external urethral sphincter during urethral pressure profilometry in male cats

Evaluation of urethral pressure profilometry (UPP) with simultaneous fine-wire electromyography of the external urethral sphincter (EUS) was conducted in 11 healthy adult male cats sedated with xylazine and ketamine. A 3.5-F urethral catheter with a closed end and two 1-mm side-ports was infused with sterile 0.9% NaCl solution at a rate of 2 to 3 ml/min. A fine-wire electromyographic (EMG) electrode was placed percutaneously into or near the external urethral sphincter prior to the onset of the UPP. The maximal urethral pressure achieved and functional profile length were recorded from UPP. Setting both catheter withdrawal rate and paper speed at 5 mm/s enabled the measurement of actual urethral length directly from UPP. Sphincter EMG activity was rated as slight (+), moderate (+ +), or intense (+ + +). All recordings were replicated once during each trial for 8 cats and trials were replicated 5 to 7 days later in 4 cats. Before catheterization, EMG activity of the external urethral sphincter was rated slight (+), whereas intense (+ + +) activity accompanied insertion. The activity evoked by movement of the catheter subsided, but intense EMG activity of the external urethral sphincter was recorded from onset to completion of catheter withdrawal in all cats in both trials. The mean maximal urethral pressure was 93.1 +/- 13.29 cm H2O. The mean function urethral length was 8.1 +/- 0.93 cm. Maximal urethral pressure or function profile length did not differ significantly between recordings within trials or between trials. Simultaneous recording of EMG activity and UPP of the external urethral sphincter was shown to be a simple, noninvasive technique for assessing neuromuscular and anatomic urethral function.     

Stress leak point pressures and urethral pressure profile tests in clinically normal female dogs.

OBJECTIVE: To develop a stress leak point pressure (LPP) test for dogs, determine LPP for continent female dogs, and determine urethral pressure profile (UPP) values for nonanesthetized, continent female dogs. ANIMALS: 22 continent female dogs weighing from 21 to 29 kg. PROCEDURE: A standard UPP test and a modification of the LPP test used in women were performed on all dogs. On 3 occasions, dogs underwent UPP testing while awake. They then were anesthetized with propofol, and LPP was measured at bladder volumes of 75, 100, and 150 ml. For LPP tests, abdominal pressure was applied by inflating a human blood pressure cuff placed around the dog's abdomen. LPP were recorded through a urethral catheter (bladder LPP) and a rectal balloon catheter (abdominal LPP). RESULTS: Mean +/- SD and median maximal urethral closure pressure was 110.1+/-20.2 and 109.0 cm water, respectively. Mean bladder LPP for the 75, 100, and 150 ml bladder volumes was 172.4 cm water. Significant differences among LPP for the 3 bladder volumes were not detected. CONCLUSIONS: Stress LPP can be recorded in female dogs.     

Comparison of the effect of propofol and sevoflurane on the urethral pressure profile in healthy female dogs

OBJECTIVE: To compare the effects of propofol and sevoflurane on the urethral pressure profile in female dogs. ANIMALS: 10 healthy female dogs. PROCEDURE: Urethral pressure profilometry was performed in awake dogs, during anesthesia with sevoflurane at 1.5, 2.0, and 3.0% end-tidal concentration, and during infusion of propofol at rates of 0.4, 0.8, and 1.2 mg/kg/min. A consistent plane of anesthesia was maintained for each anesthetic protocol. Maximum urethral pressure, maximum urethral closure pressure, functional profile length, and functional area were measured. RESULTS: Mean maximum urethral closure pressure of awake dogs was not significantly different than that of dogs anesthetized with propofol at all infusion rates or with sevoflurane at 1.5 and 2.0% end-tidal concentration. Functional area in awake dogs was significantly higher than in anesthetized dogs. Functional area of dogs during anesthesia with sevoflurane at 3.0% end-tidal concentration was significantly lower than functional area for other anesthetic protocols. Individual differences in the magnitude of effects of propofol and sevoflurane on urethral pressures were observed. CONCLUSIONS AND CLINICAL RELEVANCE: Sevoflurane is an alternative to propofol for anesthesia in female dogs undergoing urethral pressure profilometry. Use of these anesthetics at appropriate administration rates should reliably distinguish normal from abnormal maximum urethral closure pressures and functional areas. Titration of anesthetic depth is a critical component of urodynamic testing.     

Evaluation of the urodynamic and hemodynamic effects of orally administered phenylpropanolamine and ephedrine in female dogs

OBJECTIVE: To compare the urodynamic and hemodynamic effects of different dosages of phenylpropanolamine and ephedrine and determine effective dosages in increasing urethral resistance in female dogs. ANIMALS: 20 sexually intact female Beagles. PROCEDURE: Dogs were allocated into 4 groups and received phenylpropanolamine once, twice, or 3 times daily, or ephedrine twice daily, for 14 days. On days 0, 7, and 14, urethral pressure profiles were performed while dogs were anesthetized with propofol. Variables recorded included maximum urethral pressure, maximum urethral closure pressure, integrated pressure, functional profile length, anatomic profile length, plateau distance, distance before maximum urethral pressure, and maximum meatus pressure. Arterial and central venous pressures were measured before anesthetic induction and 10 and 35 minutes after induction. RESULTS: Administration of phenylpropanolamine once daily or ephedrine twice daily significantly increased maximum urethral pressure and maximum urethral closure pressure. Values for integrated pressure were significantly increased after 14 days of once-daily administration of phenylpropanolamine. Variables did not change significantly from day 7 to day 14. Diastolic and mean arterial blood pressures increased significantly during the treatment periods, and arterial pressure decreased during propofol infusion. CONCLUSIONS AND CLINICAL RELEVANCE: Oral administration of phenylpropanolamine once daily or ephedrine twice daily increased urethral resistance in clinically normal dogs and may be recommended for management of urethral sphincter mechanism incompetence. Treatment efficacy may be assessed after 1 week. Dogs with concurrent cardiovascular disease should be monitored for blood pressure while receiving alpha-adrenergic agents because of the effects on diastolic and mean arterial pressure.     

'Simultaneous' urethral pressure profilometry in the bitch: methodology and reproducibility of the technique

The technique of 'simultaneous' urethral pressure profilometry in the bitch is described. Four consecutive recordings were made from each of 100 bitches. From each recording, the maximum urethral closure pressure and functional profile length were measured and assessed for reproducibility. Analyses of variance revealed no significant differences (P greater than 0.2) between the measurements of functional profile length (means: 3.84, 3.84, 3.83, 3.80 cm; standard error of the differences: 0.037) but there were significant variations (P less than 0.001) in maximum urethral closure pressure (means of square roots: 2.26, 2.18, 2.12, 2.08 cm water; standard error of the differences: 0.042). Overall, there was a significant dependence of maximum urethral closure pressure on the measurement order (P less than 0.001). Thus, while functional profile length is a highly reproducible parameter, maximum urethral closure pressure is subject to significant variation.     

Effects of xylazine on the urethral pressure profile of healthy dogs

Thirteen healthy male dogs and 11 healthy female dogs were subjected to urodynamic assessment, using a simultaneous urethral pressure profile and urethral sphincter electromyogram (EMG). The study was done on the dogs in the nonsedated state and after xylazine sedation. Results showed a significant decrease in maximal urethral closure pressures in dogs of both sexes after they were given xylazine (from 79.79 cm of H2O to 23.00 cm of H2O in female dogs, and from 99.77 cm of H2O to 41.77 cm of H2O in male dogs). There was a significant reduction in EMG activities in dogs of both sexes after they were given xylazine. There was also little variability in measurements made on the same dog on consecutive days. Simultaneous intravesicular pressure and urethral pressure monitoring indicated that the effect of bladder distention on the urethral pressure profile was minimal and that there were no spontaneous detrusor contractions. This study indicates that xylazine produced a significant artifact in the simultaneous urethral pressure profile/EMG.     

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

OBJECTIVE: To describe a percutaneously controlled static hydraulic urethral sphincter (SHUS) and evaluate urodynamic effects of the SHUS in canine cadavers. SAMPLE POPULATION: Cadavers of 6 adult female dogs. PROCEDURE: Cadavers were obtained immediately after dogs were euthanatized. Baseline maximal urethral closure pressure (MUCP) and cystourethral leak point pressure (CLPP) were measured by use of a urethral pressure profilometer. An SHUS system was constructed by use of a silicone vascular occluder and subcutaneous infusion port. The SHUS system was then placed around the pelvic urethra in each cadaver. Measurements of MUCP and CLPP were repeated after varying occlusion of the SHUS (0%, 25%, and 50% occlusion). Baseline MUCP and CLPP values were compared with values obtained at 0%, 25%, and 50% occlusion of the SHUS by use of repeated-measures ANOVA. RESULTS: Mean +/- SD MUCP for canine cadavers was 7 +/- 1.3 cm H2O at baseline, which increased to 127 +/- 53 cm H2O after 50% occlusion of the SHUS. Mean CLPP was 11 +/- 8.6 cm H2O at baseline, which increased to 73 +/- 38 cm H2O after 50% occlusion of the SHUS. Mean MUCP and CLPP were significantly associated with the amount of occlusion. CONCLUSIONS AND CLINICAL RELEVANCE: The SHUS had positive effects on MUCP and CLPP in canine cadavers. Therefore, additional evaluation of the SHUS in live dogs is warranted.     

Evaluation of a selective neurectomy model for low urethral pressure incontinence in female dogs

OBJECTIVE: To develop a model of low urethral pressure incontinence and compare the relative contributions of the pudendal and hypogastric nerves with urethral function by performing selective neurectomy and ovariohysterectomy in dogs. ANIMALS: 19 healthy Foxhounds. PROCEDURE: Dogs were allocated into 2 groups. The first group (10 dogs) underwent bilateral hypogastric neurectomy and ovariohysterectomy and subsequent bilateral pudendal neurectomy. The second group (9 dogs) underwent bilateral pudendal neurectomy and subsequent hypogastric neurectomy and ovariohysterectomy. Urethral pressure profilometry and leak point pressure (LPP) tests were performed before and after each neurectomy. RESULTS: Before surgery, mean +/- SD LPP and maximal urethral closure pressure (MUCP) in all dogs were 169.3 +/- 24.9 cm H2O and 108.3 +/- 19.3 cm H2O, respectively; these values decreased to 92.3 +/- 27 cm H2O and 60.7 +/- 20.0 cm H2O, respectively, after both selective neurectomy surgeries. There was a progressive decline of LPP after each neurectomy; however, MUCP decreased only after pudendal neurectomy. Fifteen dogs had mild clinical signs of urinary incontinence. All dogs appeared to have normal bladder function as indicated by posturing to void and consciously voiding a full stream of urine. Urinary tract infection did not develop in any dog. CONCLUSIONS AND CLINICAL RELEVANCE: Hypogastric and pudendal neurectomy and ovariohysterectomy caused a maximum decrease in LPP whereas pudendal neurectomy caused a maximum decrease in MUCP. IMPACT ON HUMAN MEDICINE: This model may be useful for evaluation of treatments for improving urinary control in postmenopausal women.     

Urodynamic and morphologic changes in the lower portion of the urogenital tract after administration of estriol alone and in combination with phenylpropanolamine in sexually intact and spayed female dogs

OBJECTIVE: To compare the urodynamic and morphologic effects of the administration of estriol alone and in combination with phenylpropanolamine on the lower portion of the urogenital tract in female dogs. ANIMALS: 3 sexually intact and 3 spayed female Beagles without urinary incontinence. PROCEDURE: Dogs received estriol (2 mg, PO) once daily for 7 days followed by estriol (2 mg, PO) and phenylpropanolamine (1.5 mg/kg, PO) once daily for 7 days. Urethral pressure profilometry, diuresis cystometry, and vaginourethrography were performed before treatment (day 0) and at days 7 and 14. The maximum urethral pressure (MUP) and closure pressure (MUCP), urethral functional and anatomic profile lengths, integrated pressure (IP), plateau, distance before MUP, maximum meatus pressure, threshold pressure, threshold volume, compliance, urethral length, and vaginal length and width were measured. RESULTS: Before treatment, no urodynamic differences were observed between the 2 groups; however, vaginal length and width were significantly shorter in spayed dogs. Compared with day 0 values, estriol treatment significantly increased MUP, MUCP, and IP values at day 7, but at day 14, this effect decreased despite phenylpropanolamine administration. No morphologic changes from baseline were detected after either treatment in any dog. CONCLUSIONS AND CLINICAL RELEVANCE: Data suggest that estriol mainly acts on the urethral sphincter mechanism by increasing urethral resistance in sexually intact and spayed female dogs without urinary incontinence. Administration of estriol and phenylpropanolamine did not increase the urethral resistance more than estriol alone. The urodynamic effects of estriol in female dogs with urinary incontinence remain to be elucidated.     

Immediate urodynamic and anatomic response to colposuspension in female Beagles

OBJECTIVE: To characterize urodynamic function and anatomy before and after colposuspension in anesthetized female Beagles. ANIMALS: 12 adult female Beagles. PROCEDURE; During general anesthesia (thiopental sodium induction and halothane maintenance), urethral pressure profiles, leak point pressure measurements with a 50-ml bladder volume, positive contrast cystograms, and retrograde vaginourethrocystograms were performed. A caudal midline laparotomy was used to perform colposuspension. Urodynamic and radiographic studies were repeated after surgery. RESULTS: Leak point pressures were increased (120 to 168.9 cm H2O), and maximum urethral closure pressures decreased (43.7 to 19.3 cm H2O ) after colposuspension. The urethra and bladder were moved cranially; the external urethral orifice was positioned closer to the pelvic cavity, and the neck of the bladder was positioned more cranially into the abdomen. Length of the urethra, as measured by use of vaginourethrocystograms, was increased by 3%. As measured by use of urethral pressure profiles, total profile length was increased by 19.9%, and functional profile length was increased by 19.2%. CONCLUSIONS AND CLINICAL RELEVANCE: Increased leak-point pressure correlated with the expected clinical improvement attributable to colposuspension. Increased exposure of the urethra to abdominal and pelvic cavity pressures may be the mechanism by which incontinent dogs become continent after colposuspension. Results of the leak-point pressure test may correlate with clinical behavior before and after colposuspension for treatment of incontinence.     

Results of cystometry and urethral pressure profilometry in dogs sedated with medetomidine or xylazine

OBJECTIVE: To compare effects of medetomidine and xylazine hydrochloride on results of cystometry and micturition reflexes in healthy dogs and results of urethral pressure profilometry (UPP) in sedated and conscious dogs. ANIMALS: 20 dogs. PROCEDURES: Urodynamic testing was performed 6 times in each dog (3 times after administration of xylazine [1 mg/kg of body weight, IV] and 3 times after administration of medetomidine (30 microg/kg, IM). Before each episode of sedation, UPP was performed. Heart and respiratory rates and indirect blood pressures were recorded prior to and 5, 10, 20, and 30 minutes after injection of sedative. Cystometry measurements included threshold volume, threshold pressure, and tonus limb. The UPP measurements included maximal urethral closure pressure (MUCP), functional profile length, and, in male dogs, plateau pressure. RESULTS: Mean MUCP was decreased markedly in xylazine- and medetomidine-sedated dogs. Xylazine and medetomidine also decreased plateau pressure in male dogs. The MUCP measurements were consistent among days for conscious and xylazine-sedated dogs but were inconsistent for medetomidine-sedated female dogs. The proportion of valid cystometry measurements was greater for xylazine (39 of 60) than for medetomidine (27 of 60). Cystometry was considered invalid when bladder pressure reached 30 cm H2O without initiation of a micturition reflex. CONCLUSIONS AND CLINICAL RELEVANCE: Medetomidine and xylazine have similar effects on measurement of UPP and cystometry. Medetomidine was less consistent among days for UPP in female dogs and produced fewer valid cystometry tests, compared with xylazine. For urodynamic evaluations, medetomidine administered IM cannot be substituted for xylazine administered IV.     

Cystometrography and urethral pressure profiles in healthy horse and pony mares

Cystometrography and urethral pressure evaluations were performed in 7 horse mares and 5 pony mares before and after sedation with xylazine. Before sedation, mean (+/- SD) maximal bladder contraction pressure was 91.4 +/- 16.5 cm of H2O in horses and was 86.0 +/- 14.4 cm of H2O in ponies, and maximal urethral closure pressure was 49.1 +/- 19.4 cm of H2O in horses and 37.7 +/- 14.4 cm of H2O in ponies. A significant difference was not found between values of nonsedated vs sedated animals. Only values for threshold volume were significantly different (P less than 0.05) between nonsedated horses (1,982 +/- 1,241 ml) and ponies (825 +/- 412 ml).     

The Immediate Effect of Colposuspension on Resting and Stressed Urethral Pressure Profiles in Anaesthetized Incontinent Bitches

The aim of this study was to document what changes in the resting and stressed urethral pressure profile occur in the incontinent bitch with urethral sphincter mechanism incompetence (SMI) immediately after colposuspension. Resting and stressed subtracted simultaneous urethral pressure profilometry was performed immediately pre- and postcolposuspension in 26 bitches diagnosed with SMI. All of the urethral pressure profiles were measured in anaesthetized bitches using a standard technique and two orientations of the catheter transducers (dorsal and left). Readable pre- and postoperative urethral pressure profiles were obtained in 20 of the 26 bitches. Subjective and objective evaluation of the profiles showed significant differences in the profiles pre- and postcolposuspension. Immediately postoperatively there were significant ( P < .05) increases in functional profile length, maximum urethral closure pressure (MUCP), and distance between the bladder neck and the first negative respiratory peak and stressed spike. There was a significant ( P < .001) decrease in the percentage of negative spikes extending below the resting intravesical pressure on the subtracted profile. The pressure transmission profiles were significantly ( P < .001) altered by surgery. The findings presented support the hypothesis that colposuspension may restore continence by increasing pressure transmission to the proximal urethra and bladder neck. The results also suggest that immediately after surgery functional urethral length and urethral resistance are increased.     

Esophageal manometry in horses, cows, and sheep during deglutition

Esophageal pressure events during deglutition were evaluated in healthy adult animals (6 horses, 6 cattle, and 5 sheep), using a 3-side hole catheter assembly perfused with water by use of a hydraulic-capillary infusion system. The peak postdeglutition pressure, contraction time, and contraction length were determined for the cranial and caudal esophageal sphincter regions and for each functionally different region within the body of the esophagus. The percentage of deglutitions in which relaxation developed at the sphincter regions and the propagation speed (velocity at which pressure waves traversed the esophagus) for the regions within the body of the esophagus also were determined. Mean (+/- SEM) resting pressures within the cranial and caudal esophageal sphincter regions in the horse were 84.8 +/- 4.39 and 12.7 +/- 0.61 mm of Hg, respectively, with postdeglutition peaks of 208.0 +/- 4.78 and 100.0 +/- 1.06 mm of Hg, respectively. Peak postdeglutition pressure was 92.3 +/- 1.59 mm of Hg in the cranial two thirds of the esophageal body and 100.9 +/- 1.31 mm of Hg in the caudal third. Mean resting pressure of the cranial esophageal sphincter region in the cow was 82.0 +/- 7.81 mm of Hg, whereas that of the caudal esophageal sphincter region was 20.5 +/- 0.36 mm of Hg. The peak postdeglutition pressures for the cranial esophageal sphincter region, proximal portion of the esophageal body, caudal portion of the esophageal body, and caudal esophageal sphincter region in the bovine esophagus were 238.1 +/- 2.93, 105.4 +/- 1.97, 114.5 +/- 1.49, and 112.0 +/- 1.20 mm of Hg, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Equine esophageal pressure profile

Esophageal motility was studied in 5 healthy adult horses, using a 4 side-hole catheter assembly continuously perfused with distilled water. Resting pressure and maximal pressures generated during swallowing were measured over the whole length of the esophagus (mean +/- S means = 132.7 +/- 2.31 cm). Four functionally distinct regions of the esophagus were demonstrated: cranial esophageal sphincter, caudal esophageal sphincter, and "fast" and "slow" regions in the body of the esophagus. The resting pressure of the cranial and caudal esophageal sphincters were 171.1 +/- 20.45 (x +/- S means) and 10.5 +/- 0.61 (x +/- S means) mm of Hg, respectively. The maximal pressure of the "fast" and the "slow" esophageal regions and caudal esophageal sphincter were 63.1 +/- 3.75 (x +/- S means), 71.9 +/- 3.65 (x +/- S means), and 63.1 +/- 2.60 (x +/- S means) mm of Hg, respectively. The length of each region and duration of pressure events were quantitated, establishing an equine esophageal pressure profile.     

Comparison of two catheter withdrawal speeds during simultaneous urethral pressure profilometry in anesthetized bitches.

Maximal urethral closure pressure, functional profile length, and number of respiratory peaks on the resting urethral pressure profile, expressed as a percentage of those occurring on the bladder pressure recording, were compared at catheter withdrawal speeds of 1 and 3 mm/s in 30 anesthetized bitches. Significant (P less than 0.001) differences were found in maximal urethral closure pressure and percentage of transmission of respiratory peaks between the 2 speeds. Significant difference was not detected in functional profile length.     

Experimental study of urodynamic changes after ovariectomy in 10 dogs

The urodynamic changes in 10 bitches up to 18 months after they had undergone ovariectomy were investigated. There were significant decreases in the maximum urethral closure pressure, the functional urethral length and the total integrated pressure profile 18 months after spaying, resulting in a caudal shift of the urethral profile, and a deterioration of urethral closure function. Each urethral pressure profile was divided into three equal sections; the mean cranial and middle integrated pressure decreased significantly and consistently over the 18-month observation period whereas the caudal integrated pressure increased.