Ultrasonographic and Radiographic Assessment of Prostate Gland in Perineal Hernia Dogs

Background: Prostate gland affections are considered as common cause for perineal hernia in intact male dogs. Normal prostate gland is usually less distinct, radiographically; however, when enlarged it alters the anatomical position of rectum and urinary bladder and can be distinguished for its objective assessment. Radiography fails to differentiate the parenchymal abnormalities of prostate however, ultrasonography can. Therefore, this study was aimed to assess the involvement of prostate gland using radiography and ultrasonography in perineal hernia affected dogs. 
Methods: Thirty-eight intact male dogs, suffering from perineal hernia and presented during the entire year of 2018, were investigated. Both radiographic (subjective and objective) and ultrasonographic modalities were applied to assess the enlargement of prostate gland. The subjective assessment parameters on radiography (n=38) included the lifting/displacement of rectum from normal position and cranial displacement of urinary bladder. The objective parameters (n=29) included the prostate length and depth measured using inbuilt calliper of computerized radiography system and ultrasonography and comparing it with 70% of the pubic brim to sacral promontory distance. 
Result: The mean prostatic length was significantly more than the prostate depth on both radiography and ultrasonography. There was a significant positive correlation between the radiographic pubic brim to sacral promontory distance and the prostate length and depth measured on both the diagnostic modalities. The subjective assessment of prostate over emphasized the prostate depth and under estimated the prostate length compared to objective measurements on radiography. There was a significant correlation between the prostate lengths measured on radiography and ultrasonography and the lengths were not significantly different on two diagnostic modalities. Objective analysis on radiography revealed the prostate length and or/depth of 54.72% perineal hernia dogs (15/29) to be more than 70% of pubic brim to sacral promontory distance. In conclusion, the prostate affections may not always be the primary aetiology in dogs suffering from perineal hernia and prior investigation of prostate is recommended as a deciding factor for whether castration should be done a few weeks prior to or simultaneously with the perineal herniorrhaphy. The increased length of the prostate is a better indicator of prostatomegaly than the depth.