In dogs, fusion of the paramesonephric (mullerian) duct is responsible for the formation of the uterus, uterine tubes, cervix, and vagina,1–4 whereas the urogenital sinus develops into the vestibule, urethra, and urinary bladder.2–4 The caudal aspect of the fused ducts projects into the urogenital sinus, becomes canalized, and forms the vaginal opening, with a membrane resulting in the hymen.3,4 Abnormal development during this embryological process can result in malformations of the urinary tract, including an imperforate or persistent hymen, vestibulovaginal stenosis, vaginal segmental hypoplasia or aplasia, and PPMRs.1,3–6
Definitions of these abnormalities in the literature lack consistency. The general term VVSR is used to describe any dorsoventrally or ventrolaterally directed band or wall of tissue in the vagina present between the cervix and vestibule, starting at the vaginal opening. A PPMR is a membrane in which the tissue extends cranially from the vestibulovaginal junction < 1 cm, excluding a lesion that can be digitally perforated, like an imperforate hymen. A vaginal septum is a membrane in which the tissue extends cranially > 1 cm, stopping prior to the cervix. A dual vagina is a membrane in which the tissue extends from the vestibulovaginal junction to the cervix, splitting the vagina into 2 compartments.
The clinical implications of various VVSRs are currently unclear. These may be an incidental finding in some dogs, whereas others may develop a variety of signs, including difficulty during natural breeding, persistent urinary incontinence, vaginal pooling of urine, chronic recurrent UTIs, dysuria, infertility, recurrent vaginitis, dystocia, vulvar dermatitis, and ambiguous external genitalia.1–5,7,8 These anomalies have no reported genetic or breed predisposition.1,4 The overall prevalence of these malformations is also unknown, given that most dogs are spayed early in life, are never bred, and may never have clinical signs warranting further investigation.1,2,4,9 These defects often occur concurrently with other congenital malformations and were recently reported in 93% of female dogs with ectopic ureters.10 Multiple malformations in the same patient also make the clinical implications of VVSR difficult to elucidate.
Even though there are questionable clinical implications for these malformations, various treatments have been attempted, most of which are performed via invasive open surgery. Some of these include episiotomy for surgical transection of the vertical septum, T-shaped vaginoplasty, vaginal resection and anastomosis with a pelvic osteotomy, and vaginectomy.2–5,8,11,12 Complications and risks associated with surgical correction of the malformations include dysuria, pollakiuria, vaginal bleeding, iatrogenic urethral damage, neurologic damage, urinary incontinence, urethral or colonic obstructions from scar tissue, and the inability to breed following surgery.4,8,12 These risks appear considerable, particularly when few data are available on the clinical necessity of fixing these malformations.
The use of ELA for treatment of vaginal malformations is a noninvasive alternative to surgery for the fixation of these remnants.5,7,10,13,14 The purpose of the study reported here was to describe a noninvasive diagnostic and therapeutic option for various vaginal malformations (PPMR, vaginal septum, and dual vagina) with an ELA technique and retrospectively review the patients' clinical signs and short- and long-term outcomes. Our hypothesis was that this procedure would be both safe and effective for the permanent resolution of various VVSRs in dogs, avoiding the need for more invasive surgical approaches for correction for this condition, which has unknown clinical implications for patients.
Materials and Methods
Case selection criteria—Female dogs with PPMR, vaginal septum, or dual vagina (Figure 1) examined and treated endoscopically from April 2007 to March 2011 were included. These patients were treated at either the Matthew J. Ryan University of Pennsylvania (2007 to 2009) or the Animal Medical Center (2009 to 2011). All patients with vaginal remnants were treated with ELA by 1 author (ACB). Patients were excluded if they did not have an opening to their vagina, if the band could be digitally torn without the need for ELA, or if they had < 6 months of follow-up after ELA of vaginal remnants.
Endoscopic images of the vagina of 3 patients with various VVSRs before (A, B, and C) and after (D, E, and F) ELA of septal remnants. Patients are positioned in dorsal recumbency. A—A 1-year-old spayed female Laborador Retriever with a persistent paramesonephric remnant (< 1 cm in length; white arrow) before ELA. B—A 7-month-old spayed female Golden Retriever with a vaginal septum (> 1 cm in length; white arrow) that ends midvagina before ELA. C—A 9-month-old spayed female Golden Retriever with a dual vagina having a complete septum to the level of the cervix (black arrow). D—The same dog as in panel A after ELA. Notice the urethral meatus (yellow arrow) and the neovaginal orifice. E—The same dog as in panel B with a vaginal septum after ELA. The opening to the cervix is seen at the end of the blue catheter showing the septum is approximately halfway down the length of the vagina after it is cut. F—The same dog as in panel C with a dual vagina after ELA when the septum (black arrow) is cut to the level of the cervical opening. In panels A, B, and D, the urethral opening is indicated by the yellow arrow.
Citation: Journal of the American Veterinary Medical Association 244, 8; 10.2460/javma.244.8.944
Historical and laboratory data—All dogs underwent a CBC, serum biochemical analysis, urinalysis, and bacteriologic culture of urine and antimicrobial susceptibility testing prior to the procedure. Data regarding signalment, continence, history of a UTI or vaginitis, previous imaging findings, clinical signs, duration of signs, findings of physical examination including a digital vaginal examination, morphology of the malformation (PPMR, vaginal septum, or dual vagina and vaginal and vulvar anatomy), and the presence of concurrent urogenital tract abnormalities (eg, ectopic ureters, pelvic bladder, bladder shape, renal anatomy and dimensions, and length of urethra) were recorded when available.
ELA procedure—Patients were anesthetized and positioned in dorsal recumbency, and the vulva was clipped of hair and aseptically prepared. Cefazolin (22 mg/kg [10 mg/lb], IV, q 2 h) was administered prophylactically during surgery to patients that were not being treated with an antimicrobial for a previously diagnosed UTI. A rigid cystoscopea–c was advanced into the vestibule with saline (0.9% NaCl) solution irrigation. The vaginal opening was identified and then the urethra was entered in a retrograde manner for a full cystourethroscopy, allowing for evaluation of the urethra, ureteral openings, and urinary bladder. Correction of any anomalies that could be performed endoscopically was conducted (ie, ELA of ectopic ureters). The length of the urethra (cm) was recorded. The presence of an intrapelvic bladder or short urethra was also recorded. Then, the vagina was entered, and each malformation identified was classified as either a PPMR, vaginal septum, or dual vagina (Figure 1) on the basis of measurements of the septum with an open-ended ureteral catheterd with 1-cm marks throughout its length.
The open-ended ureteral catheterd was advanced over a guide wiree through the working channel of the endoscope to the level of the cervix (Figure 2). Next, the endoscope was removed over the guide wire–catheter combination and replaced next to the guide wire and catheter inside the vestibule at the opening of the vagina. A laser fiber was then placed inside the working channel of the endoscope. The laser used was either a diode laser with a 600-μm end-fire laser fiberf (18 to 22 W) or a holmium:yttrium-aluminum-garnet laserg (10 to 12 Hz; 0.7 to 1.2 J; pulse width, 700 milliseconds) with a 400-μm end-fire laser fiber. The malformation was then laser ablated from the caudal aspect to the most cranial aspect. The catheter was used to mark the contralateral vaginal compartment until the vagina was an open tube with a single opening.
Endoscopic images of a 9-month-old spayed female Wheaten Terrier with a vaginal septum during ELA. The dog is in dorsal recumbency. Notice the green-light laser beam of the holmium:yttrium-aluminum-garnet laser. A—The vaginal remnant (black arrowhead) prior to entering the vagina, with images acquired from the vestibule. B—A catheter (red arrow) entering the left opening of the vaginal remnant (black arrowhead) as the laser fiber (black arrow) is guided through the working channel of the endoscope. C—The catheter is in the left compartment of the vagina (red arrow) while the laser (black arrow) is cutting the remnant. Notice that there is no bleeding. D—As the remnant is lasered (black arrow) from a caudal to cranial direction, the catheter (red arrow) is able to be seen more clearly, demarcating the left compartment. E—The vaginal septum is nearly completely cut by the laser (black arrow). The catheter is still visible (red arrow). F—The entire vaginal septum is cut, and the vaginal opening is seen from the vestibulovaginal junction, showing the entire catheter (red arrow). In panels A and B, the yellow star is the urethral meatus.
Citation: Journal of the American Veterinary Medical Association 244, 8; 10.2460/javma.244.8.944
Dogs were administered meloxicam (0.1 mg/kg [0.5 mg/lb], SC) on recovery from the laser procedure if there was no concern for impaired renal function, and the urethra, vagina, and vestibule were infused topically with a bupivicaine (0.3 mg/kg [0.14 mg/lb]) and saline solution mixture (1:1 [vol/vol]) for local transurethral analgesia.
Postsurgical management—On discharge of animals from the hospital, owners were provided with an analgesic to be administered for signs of discomfort as needed. This was typically an NSAID, specifically meloxicam (0.1 mg/kg, PO, q 24 h), to be administered for 1 to 3 days if dogs were nonazotemic and had no evidence of hydroureter or hydronephrosis. Alternatively, tramadol was administered (2 to 5 mg/kg [0.9 to 2.3 mg/lb], PO, q 8 h for 24 hours). Patients were administered amoxicillin-clavulanic acid (15 mg/kg [7 mg/lb], PO, q 12 h) for 3 to 7 days, depending on underlying disease (PPMR alone vs ectopic ureters). Bacteriologic culture of urine was performed 2 to 4 weeks after antimicrobial treatment in all patients and was recommended to be repeated at 8 weeks, 3 months, and 6 months, and then every 6 months thereafter.
Follow-up—For most dogs in which concurrent ELA of ectopic ureters was performed, a cystoscopic examination was performed 6 to 8 weeks after the procedure as part of a concurrent prospective study10 for correction of ureteral ectopia. At that time, each vaginal remnant was reassessed (Figure 3). Owners were asked to complete a written questionnaireh grading continence status, recurrence of UTIs, quality of life, and any concurrent medical concerns of their pet. Incontinence was defined as any persistent or intermittent involuntary leakage of urine. Continence was graded on a scale of 1 through 10 as previously reported,10 where 1 was minimally continent (leaking all the time), 5 was moderately continent (leaking when lying down or when the bladder is full but able to hold urine between urinations and to produce a stream and puddle of urine), and 10 was perfectly continent (no leakage at all). All owners were contacted and asked to complete the questionnaire 1 week after the procedure, 6 to 8 weeks after the procedure, and at last follow-up.
Endoscopic image of the vaginal vestibule of a 9-month-old spayed female mixed-breed dog 6 weeks after ELA of a septal remnant, with the patient in dorsal recumbency. The black arrow is where the remnant was prior to ELA, and the yellow star is the urethral meatus.
Citation: Journal of the American Veterinary Medical Association 244, 8; 10.2460/javma.244.8.944
Statistical analysis—Normality of distribution of baseline continuous parameters was assessed with the Shapiro-Wilk test. No continuous variables followed a normal distribution, so median, IQR, and range were used to describe these parameters. Categorical variables were presented as frequencies or percentages. A Wilcoxon signed rank test for matched pairs was used to compare preprocedure continence scores with continence scores at 1 week and at the final data collection point. The McNemar test was used to compare frequency of UTI before the procedure with frequency of UTI after the procedure. Statistical analyses were performed with a commercial software program.i Values of P < 0.05 were considered significant.
Results
Thirty-six female dogs with vaginal malformations were included in the study. Eighteen (50%) dogs were spayed, and 18 dogs were sexually intact at the time of the procedure. All dogs were spayed during the course of the study. There were 4 mixed-breed dogs and 32 purebred dogs, including the following breeds: Golden Retriever (n = 13), Wheaten Terrier (3), Labrador Retriever (3), English Bulldog (2), Newfoundland (2), and 1 each of Bichon Frise, Rottweiler, Doberman Pinscher, Miniature Poodle, Havanese, Weimeranar, Jack Russell Terrier, Miniature Schnauzer, and Bernese Mountain Dog. Median weight at initial evaluation was 17.8 kg (39.2 lb; IQR, 10.0 to 24.8 kg [22.0 to 54.6 lb]; range, 2.5 to 49.5 kg [5.5 to 108.9 lb]), and the median adult weight was 24.1 kg (53.0 lb; IQR, 17.3 to 29.0 kg [38.1 to 63.8 lb]; range, 3.6 to 49.4 kg [7.9 to 108.7 lb]. Median age at the time of the procedure was 12 months (IQR, 6 to 24 months; range, 3 to 173 months).
Twenty-six of 36 (72%) dogs had urinary incontinence, 2 (6%) had UTIs, and 8 (22%) had both urinary incontinence and UTIs. The age of onset of urinary incontinence was < 6 weeks in 20 of 36 (56%) dogs and > 6 years in 1. In 9 (25%) dogs, urinary incontinence was present since the dogs were owned; age of onset was unknown in 6 (17%). Vaginitis was present in 2 dogs, as determined on the basis of physical examination findings and cytologic evaluation. White perivulvar plaques were present in one of these dogs, and the other dog had vulvar erythema, pruritis, and vaginal discharge. Cytologic evaluation confirmed the presence of fungal infection in one dog and bacterial infection in the other. A hooded vulva was reported in 13 of 36 (36%) dogs. Preanesthetic serum biochemical concentrations were evaluated in all patients, and no abnormalities were detected. A history of a positive result of a bacteriologic culture of urine was documented in 28 of 32 (87.5%) dogs, and Escherichia coli was the predominate isolate (5/28 dogs). Abdominal ultrasonography was performed in 11 dogs. Abnormalities included ureteral ectopia (4/11), pyelectasia (3/11), hydroureter (1/11), and abnormal bladder position (2/11). Five dogs had a history of previous surgical treatment of their ectopic ureters.
Endoscopic evaluation confirmed the presence of a vaginal malformation in all 36 dogs, including a PPMR in 19 (53%), vaginal septum in 11 (30%), and dual vagina in 6 (17%). For ELA of vaginal remnants, the diode laser was used in 28 of 36 dogs and a holmium:yttrium-aluminum-garnet laser was used in 8. The median energy for the diode laser was 20 W (range, 18 to 25 W) and for the holmium:yttrium-aluminum-garnet laser was 10 W (range, 10 to 12 W) or 1 J (range, 0.7 to 1.2 J) at 10 Hz (range, 10 to 12 Hz). The median procedure time was 47.5 minutes (range, 30 to 120 minutes), including the time for all concurrent procedures performed (ELA of ectopic ureters).
Concurrent urogenital anomalies were found in 32 of 36 (89%) of dogs. Ectopic ureters were present in 30 of 36 (83%) dogs, of which 5 were previously treated surgically and 25 were treated via ELA of ectopic ureters at the time of the ELA of the vaginal remnant. A short urethra and an intrapelvic bladder were found in 16 (44%) and 13 (36%) of dogs, respectively. Other less common malformations included hydroureter (5/36 [14%]), urachal diverticulum (4/36 [11%]), bladder polypoid mass (2/36), ureteroceole (1/36), and a urethral inflammatory polyp (1/36).
Six complications occurred, including mild dysuria in 5 dogs and vaginal wall perforation in 1 dog. The dysuria resolved in all 5 dogs within 24 hours, and 4 of 5 dogs had concurrent ELA of ectopic ureters performed during the cystourethroscopy. One of these 5 dogs had a hydraulic occluder placed at the time of ELA of vaginal remnants for persistent incontinence after surgical treatment of the ectopic ureters failed to improve the incontinence. In another dog, the laser perforated the lateral aspect of the vaginal wall. This was because of dislodgement of the contralateral vaginal catheter to mark the end of the vaginal remnant, which aids in demarcating the vaginal wall. This patient was reassessed endoscopically 8 weeks later, and the perforation healed with no necessary intervention. There were no short- or long-term effects from this complication.
Eighteen (50%) dogs had a recheck endoscopy 6 weeks after ELA of vaginal remnant. At that time, 100% were fully healed with no reoccurrence of the malformation and a fully open vaginal lumen (Figure 3). Both dogs with vaginitis prior to laser ablation had complete resolution of their clinical signs. There was a significant improvement in median continence scores in all dogs evaluated after the ELA (n = 36). The median score prior to ELA of vaginal remnant (n = 36) was 3 of 10 (IQR, 1 to 6.0). The median score at 1 week (n = 32) was 10 (IQR, 8.25 to 10; P < 0.001). The median score at the time of last follow-up (n = 36) was 9.25 (IQR, 8 to 10; P < 0.001). Twenty-eight of 32 (87%) dogs had a positive urine culture result recorded before ELA of vaginal remnants, compared with 23 of 36 (64%) at any point within the follow-up period following ELA of vaginal remnants (P = 0.039). One dog died of presumptive pyelonephritis 4 months following the procedure. All other dogs were still alive at last follow-up. The median follow-up time was 34 months (range, 8 to 57 months).
Discussion
In the present study of 36 dogs treated over a 4-year period, results indicated that ELA provided an effective, safe, and minimally invasive treatment option for various VVSRs, avoiding the need for more invasive surgery. In this study, vaginoscopy was used as a sole diagnostic tool for VVSR and was able to identify vaginal malformations in all cases, providing simultaneous treatment via ELA. The most common malformation observed was PPMR (53%), followed by a vaginal septum (30%) and then a dual vagina (17%). This ELA procedure was found to be both safe and effective in removing this membrane and maintaining a normal vaginal opening long term and was associated with minimal morbidity.
The definitions of the various vestibulovaginal malformations treated in patients in the present study are not consistent in the literature, which makes diagnosis, treatment options, and outcomes difficult to discuss and compare. In the present study, VVSRs included PPMRs, vaginal septa, and dual vaginas. Vestibulovaginal stenosis, referring to an annular narrowing of the vestibulovaginal junction, was not found in any patient. The definition of a persistent imperforate hymen remains as a thin membrane at the junction of the paramesonephric tubercle and urogenital sinus, and these cases were not included in this study because they do not typically require ELA and can be digitally broken.
Sexually intact female dogs (50%) were affected as often as were spayed female dogs (50%). Young large-breed dogs, most commonly Golden Retrievers (36%), were most affected. Sixty-seven percent of dogs in this study were evaluated because of urinary incontinence that was evident at < 6 weeks of age. The specific role of vaginal malformations in urinary incontinence, vaginitis, and UTIs is not clear, given that they may be an incidental finding in some animals but potentially contributing to or causing clinical signs in others.2,3,8,9,11 It has been suggested that VVSRs can allow for pooling of urine in the vagina and keep the urethral meatus open, both of which contribute to leakage of urine, vaginitis, and recurrent UTIs.2,3,5,8,12
Significantly (P < 0.001) improved short-term (1 week) and long-term (> 6 months) median continence scores (10 and 9.25, respectively) were attained, compared with that of the dogs prior to ELA (median score, 3). There was also a significant (P = 0.039) decrease in the rate of UTIs from prior to the procedure to the final data collection point in all dogs. The 2 dogs with vaginitis documented prior to the procedures had complete resolution of signs after the procedure. Concurrent anomalies were found and corrected if possible in 32 of 36 (89%) dogs that had vaginal malformations, with 30 (83%) having concurrent intramural ectopic ureters. Other abnormalities found included short urethras, intrapelvic bladders, hydroureter, urachal diverticulum, bladder polypoid masses, ureteroceole, and urethral dysplastic abnormality. As a result, we feel that it is extremely likely that the improvement in clinical signs observed was related to fixation of the concurrent abnormalities, rather than the VVSRs alone, especially considering a previous report10 in which significant improvement occurred in dogs with incontinence secondary to ELA of ectopic ureters alone. The high postoperative UTI rate (64%), although improved, also suggests that concurrent abnormalities play a role in clinical signs. The anatomic defect found in these dogs may predispose them to chronic UTIs for the rest of their life. We suggest that this further emphasizes the importance of having a noninvasive treatment option for this condition, considering that the traditional surgical treatment alternatives have more risks, compared with ELA,4,5,8,12,15 and the clinical implications of vaginal remnants remain unclear.
Unfortunately, statistical evaluation of the effects of the procedure on continence scores or incidence of UTI in dogs with vaginal malformations alone, without concurrent malformations, was of low yield because there were only 6 of these dogs. All 6 dogs had improvement or resolution of their lower urinary tract signs (3 dogs were incontinent, 2 had recurrent UTIs, and 1 dog had both) after ELA of vaginal remnants. The main goal of this study was to describe the ELA of vaginal remnant technique and evaluate longevity in maintaining a patent vaginal lumen. A future goal is to attempt to further characterize and describe the potential clinical benefits of VVSR fixation alone.
Complications with endoscopy are possible and may include urethral tears, vaginal tears, and mucosal trauma.4,5,15 In the present study, laser ablation was used, with a minimal complication rate. The dog with laser perforation of the vaginal wall healed well at reevaluation and did not have any known ill effect from this event. None of the animals that were reevaluated with endoscopy had recurrence of the vaginal band.
The limitations of this study include its retrospective nature and small sample size, in addition to the simultaneous correction of multiple anomalies in the same dog. As a result, improvement in clinical signs is unable to be attributed to the fixation of one anomaly versus another. The variable number of procedures performed may have been a confounding factor in determining the number of postoperative complications and procedure time associated with ELA of vaginal remnants.
In conclusion, ELA of vaginal remnants was found to be a safe alternative to surgery for the treatment of many vestibulovaginal defects in dogs and was an effective long-term solution for VVSRs. Diagnosis and treatment can occur concurrently with this technique, eliminating the need for separate anesthetic episodes. Endoscopic-guided laser ablation of vaginal remnants is a cost-effective option with potentially less morbidity than the surgical alternatives, especially for a disease process that currently has unknown implications for the patient.
ABBREVIATION
| ELA | Endoscopic-guided laser ablation |
| IQR | Interquartile range |
| PPMR | Persistent paramesonephric septal remnant |
| UTI | Urinary tract infection |
| VVSR | Vestibulovaginal septal remnant |
Rigid endoscope, 1.9-mm 30° lens, Karl Storz Endoscopy, Culver City, Calif.
Rigid endoscope, 2.7-mm 30° lens, Richard Wolf, Vernon Hills, Ill.
Rigid endoscope, 4-mm 30° lens, Karl Storz Endoscopy Inc, Culver City, Calif.
4-5F open-ended ureteral catheter, Cook Medical Inc, Bloomington, Ind.
Weasel Wire 0.025- or 0.035-inch hydrophilic angle-tipped guidewire, Infiniti Medical LLC, Menlo Park, Calif.
600-μm diode laser fiber and 25-W diode laser, Lumenis Inc, Santa Clara, Calif.
400-μm Hol:YAG laser fiber and 30-W Hol:YAG lithotrite, Convergent Inc, Alameda, Calif.
A copy of the questionnaire is available from the corresponding author.
Stata, version 12, StatCorp LP, College Station, Tex.
References
1. Root MV, Johnston SD, Johnston GR. Vaginal septa in dogs: 15 cases (1983–1992). J Am Vet Med Assoc 1995; 206:56–58.
2. Kyles AE, Vaden S, Hardie EM, et al. Vestibulovaginal stenosis in dogs: 18 cases (1987–1995). J Am Vet Med Assoc 1996; 209:1889–1893.
3. Holt PE & Sayle B. Congenital vestibulo-vaginal stenosis in the bitch. J Small Anim Pract 1981; 22:67–75.
4. Wykes PM, Soderberg SF. Congenital abnormalities of the canine vagina and vulva. J Am Anim Hosp Assoc 1983; 19:995–1000.
5. Whitacre MD, Tate LP, Estill CT, et al. Transendoscopic Nd:YAG laser ablation of vaginal septa in a bitch. Vet Surg 1991; 20:257–259.
6. Cannizzo KL, McLoughlin MA, Mattoon JS, et al. Evaluation of transurethral cystoscopy and excretory urography for diagnosis of ectopic ureters in female dogs: 25 cases (1992–2000). J Am Vet Med Assoc 2003; 223:475–481.
7. Wang KY, Samii VF, Chew DJ, et al. Vestibular, vaginal and urethral relationships in spayed and intact normal dogs. Theriogenology 2006; 66:726–735.
8. Kieves NR, Novo RE, Martin RB. Vaginal resection and anastomosis for treatment of vestibulovaginal stenosis in 4 dogs with recurrent urinary tract infections. J Am Vet Med Assoc 2011; 239:972–980.
9. Wang KY, Samii VF, Chew DJ, et al. Vestibular, vaginal and urethral relations in spayed dogs with and without lower urinary tract signs. J Vet Intern Med 2006; 20:1065–1073.
10. Berent AC, Weisse C, Mayhew PD, et al. Evaluation of cystoscopic-guided laser ablation of intramural ectopic ureters in female dogs. J Am Vet Med Assoc 2012; 240:716–725.
11. Crawford JT, Adams WM. Influence of vestibulovaginal stenosis, pelvic bladder, and recessed vulva on response to treatment for clinical signs of lower urinary tract disease in dogs: 38 cases (1990–1999). J Am Vet Med Assoc 2002; 221:995–999.
12. Mathews KG. Surgery of the canine vagina and vulva. Vet Clin North Am Small Anim Pract 2001; 31:271–290.
13. Berent AC, Mayhew PD & Porat-Mosenco Y. Use of cytoscopicguided laser ablation for treatment of intramural ureteral ectopia in male dogs: four cases (2006–2007). J Am Vet Med Assoc 2008; 232:1026–1034.
14. Smith AL, Radlinsky MG, Rawlings CA. Cystoscopic diagnosis and treatment of ectopic ureters in female dogs: 16 cases (2005–2008). J Am Vet Med Assoc 2010; 237:191–195.
15. Holt PE, Gibbs C & Latham J. An evaluation of positive contrast vagino-urethrography as a diagnostic aid in the bitch. J Small Anim Pract 1984; 25:531–549.
