Treatment of canine perineal hernia with a fascia lata graft is noninferior to the elevation of the internal obturator muscle: a prospective randomized trial of 66 dogs.

OBJECTIVE: To compare the recurrence rate after herniorrhaphy of canine perineal hernia (PH) using elevation of the internal obturator muscle (EIOM) or fascia lata graft (FLG) and assess how clinical signs related to defecation evolve during 12 months postoperatively. ANIMALS: 66 client-owned male dogs undergoing PH surgery between March 1, 2017, and December 31, 2020. METHODS: Dogs were randomized into 2 groups (EIOM = 36; FLG = 30) applying 2 stratification factors: preoperative bladder location and the defecation signs score (DSS). Follow-up visits were at 2 weeks and 3, 6, and 12 months postoperatively. The main outcome, the recurrence of PH was evaluated by rectal examination. We evaluated the noninferiority of FLG to EIOM from the difference in recurrence proportions between the techniques (95% CI), comparing the CI with a pre-defined noninferiority margin (15%). To evaluate defecation signs, the DSS was calculated from the owner questionnaire and assessed with a linear mixed model (P < .05 significant). RESULTS: In 63 dogs attending the 12-month follow-up, the recurrence rate was 8.8% (3/34) in the EIOM and 10.3% (3/29) in the FLG group. The CI (-11.94% to 14.99%) was below the pre-defined margin, indicating the noninferiority of FLG. After surgery, the DSS decreased (P < .001), remaining low during the follow-up. CLINICAL RELEVANCE: FLG was non-inferior to EIOM when considering recurrence. The DSS decreased postoperatively and complications were uncommon. FLG is a useful alternative for the treatment of canine PH.

Dimensional and spatial computed tomographic abnormalities of the rectum and prostate are only partly reversible after surgical repair of perineal hernia in dogs.

Caudal protrusion of pelvic organs and dilatation and deviation of the rectum with perineal hernia (PH) have not previously been studied using CT, and it is not known how completely the changes normalize after PH repair. Objectives of this prospective experimental case series were to evaluate the dimensions and shape of the rectum and the volume, location, and other features (enhancement pattern, presence of cysts, and mineralizations) of the prostate of 66 dogs on CT before and 3 months after PH repair. The rectal cross-sectional areas were measured at intrapelvic and caudal locations, and the shape was categorized as straight, deviated, flexure, or caudal fold on dorsal images. According to paired samples t-tests, the caudal rectal dimensions were significantly larger (P < .001) than the intrapelvic dimensions both before and 3 months after PH repair, and according to linear mixed models, the intrapelvic dimensions increased significantly (P < .001) after repair. Before PH repair, the most common rectal shape was flexure (69.2%); after repair, the number of dogs having a straight rectum increased significantly (P < .001) according to the McNemar paired-samples proportion test. We were also able to show that rectal dimensions increased after PH repair despite straightening in most dogs. According to the linear mixed model, prostate ratio volume, and according to Wilcoxon signed ranks test, the number of prostates with intraprostatic cysts decreased significantly (both P < .001) after PH repair, but the proportion of prostates located in the caudal or perineal area did not. Small mineralizations remained in some dogs.

CT measurement of prostate volume using OsiriX® viewer is reliable, repeatable, and not dependent on observer, CT protocol, or contrast enhancement in dogs.

Computed tomography (CT) is an established method for evaluating dogs with suspected prostatic disease; however, publications assessing the effects of varying factors on prostate volume measurements are lacking. The objectives of this two-part, observer agreement, methods comparison study were to assess observer agreement and the effects of varying CT technical parameters for volume measurements of canine prostate glands on CT images using OsiriX® DICOM viewer software. In the first retrospective study, two observers measured prostate volumes of 13 client-owned dogs thrice on noncontrast and contrast CT images. In the second prospective study, two observers measured the prostate volume of 10 cadavers using five different CT protocols and eight cadavers using three slice thicknesses. Observer agreement analyses were performed, and prostatic CT volume measurements were compared with water displacement volume measurements. Intra- and interobserver variability and the effect of contrast enhancement were found to be minimal when a one-way analysis of variance model and intraclass correlation coefficients were used. No significant differences emerged between different protocols and slice thicknesses using a linear mixed effects model. When the prostate CT volume was compared using a Bland-Altman plot with the reference volume acquired by the water displacement method, agreement without consistent bias between the methods was shown, and over 90% of measurements were located within the 95% limits of agreement. The findings supported using OsiriX® software for CT prostatic volume measurements in dogs.

CT imaging of dogs with perineal hernia reveals large prostates with morphological and spatial abnormalities.

The etiology of canine perineal hernia (PH) remains unclear, although as a disease of older male dogs, it is likely to be hormonal. The role of the prostate in the formation of PH has been questioned; however, prospective and systematic evaluation of prostates in these dogs is absent in the literature. In this prospective case-control study, CT imaging was used to assess prostatic changes in dogs with PH (n = 46) and compare these findings with those of intact age-matched male dogs (n = 23). Using the OsiriX® DICOM viewer, we measured prostatic volume and correlated it with the size of the dog by using the length of the sixth lumbar vertebra. In addition, we recorded spatial and morphological changes of the prostate, such as heterogenicity, intra- and paraprostatic cysts, and mineralizations, as well as prostatic location and rotation. We found that dogs with PH had larger prostates (P < .001) that more often contained cysts (P < .001) and had larger cyst diameters (P = .013) than age-matched controls. Prostates of PH dogs also contained paraprostatic cysts (17.4%) and focal mineralizations (32.6%), which were absent in the control group. Abnormal rotation and location of the prostate were common in dogs with PH. In conclusion, these findings support the use of CT as an adjunct diagnostic imaging modality for the evaluation of the prostate in dogs with PH. Further studies are needed to evaluate nonprostatic CT findings in the pelvic cavity of PH dogs.