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.