How is ectopic ureter diagnosed in dogs and what are the outcomes of laser ablation treatment?

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Cystoscopy is the gold-standard diagnostic modality for ectopic ureter (EU) in dogs, with 100% sensitivity for identifying ureteral ectopia and the added advantage of allowing concurrent lower urinary tract evaluation and same-session treatment.10 Abdominal ultrasonography is a reasonable first-line screening tool, with a diagnostic accuracy of 95% for EU detection, and it allows concurrent assessment of the upper urinary tract for hydroureter, hydronephrosis, renal hypoplasia, and renal aplasia.10 CT and cystoscopy have the highest agreement with surgical and necropsy findings for both detection and phenotypic characterization of EU.2 Retrograde contrast fluoroscopy performed concurrently with cystoscopy confirms intramural course and identifies stenotic ureteral orifices.1 Phenotypic characterization at diagnosis directly determines treatment eligibility. Intramural EU accounts for 87%–99% of canine ureteral ectopia10 and is the only phenotype amenable to cystoscopic-guided laser ablation (CLA).2 Extramural EU requires open surgical correction. Concurrent urogenital anomalies — including pelvic bladder, short urethra, paramesonephric remnant, double vagina, and vaginal septum — are present in 81%–93% of EU cases and contribute substantially to persistent postoperative incontinence.11 CLA is the treatment of choice for intramural EU in female dogs, combining retrograde uretero-cystography and cystoscopy to identify the distal ureteral orifice, followed by laser ablation of the medial wall of the intramural tunnel to relocate the ureteral orifice into the bladder trigone.2 The Holmium:YAG (Ho:YAG) laser is the instrument used for ablation.1 The procedure is performed the same day as diagnosis and allows same-day discharge.9 Continence outcomes after CLA in female dogs range from 25%–80% without additional therapy, increasing to 67.7%–81% with adjunctive medical or surgical management.10 In a direct comparison of CLA versus neoureterostomy, CLA was associated with fe