Sinography in the investigation of draining tracts in small animals: retrospective review of 25 cases.

The signalment, history, clinical signs, radiographic findings, and surgical findings of 25 consecutive animals that had sinography were reviewed to assess the contribution made by sinography to diagnosing and surgically managing draining tracts in small animals. There were 23 dogs and 2 cats; a variety of breeds and both sexes were represented (18 males, 7 females). Before referral the mean duration of clinical signs was 9.8 months (range, 0.5 to 33 months) and a mean of 2.0 surgical procedures (range, 1 to 5) had been performed. Sinuses occurred in a variety of locations, most commonly the neck (10), head (6), and paws (5). The most common cause was foreign body (15). Survey radiographs showed abnormalities in 21 of 26 (78%) instances, including soft-tissue swelling (11), chronic-appearing periosteal reaction on adjacent bones (5), possible foreign body (4), and gas in soft tissues (2). Sinography (or fistulography) enabled definite diagnosis of the cause of the sinus (or fistula) in 15 of 26 (58%) instances and demonstrated 13 of 15 foreign bodies (sensitivity 87%; specificity 100%). Tracts caused by an esophageal perforation and otitis media were also correctly shown by fistulography. In 11 animals, sinography indicated that the position or extent of the lesion was different to that expected on the basis of clinical signs and survey radiographs.