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OG26.1-2 | Genital Injuries and Fistulae — SDL Guide (Part 3)
Self-Assessment
You have now covered the full clinical arc for genital injuries and fistulae — from the presentation of acute obstetric lacerations to the pathophysiology of pressure necrosis, the classification of urogenital and rectovaginal fistulae, the two-step dye-test diagnostic approach for distinguishing VVF from UVF, and the fundamental principle that timing of surgical repair determines success or failure. Before you attempt the questions below, mentally rehearse the key decision points: What makes VVF clinically different from UVF? What is the first investigation you would order and what result would confirm each diagnosis? What is the minimum waiting period before elective repair of an obstetric VVF with oedematous tissues, and why? Which fistula type requires ureteric reimplantation rather than a simple vaginal repair? Use the questions below to test the precision of your recall — pay attention to the details that distinguish closely related options.
SELF-CHECK
Which of the following correctly describes a third-degree (3b) perineal tear?
A. Skin and vaginal mucosa only; no muscle involvement
B. Perineal muscles torn; external anal sphincter intact
C. More than 50% of the external anal sphincter torn; internal anal sphincter intact
D. External anal sphincter, internal anal sphincter, AND anorectal mucosa all disrupted
Reveal Answer
Answer: C. More than 50% of the external anal sphincter torn; internal anal sphincter intact
The grading is: 1st = skin/mucosa only; 2nd = perineal muscles + intact EAS; 3rd = EAS involvement (3a = <50%, 3b = >50%, 3c = EAS + IAS torn); 4th = EAS + IAS + anorectal mucosa. Option C correctly describes 3b. Option D describes a fourth-degree tear. Third and fourth degree tears together are called OASIS (obstetric anal sphincter injuries).