Perineal trauma and OASIS — structured SAQ (15 marks)

(a) Assessment of the genital tract (4 marks)

One mark per element, maximum four. Marks are for the step and its justification. ^[1]

• Explain, consent and provide effective analgesia before you look — inhalational analgesia at minimum; the examination is uncomfortable and an inadequate examination is the commonest source of a missed injury.^[1]
• Optimise the conditions — lithotomy position, a good light, an assistant to retract. Maintain lithotomy only as long as the assessment and repair require.^[1]
• Systematic visual assessment — identify all structures involved, find the apex of the injury, and assess the bleeding. Look specifically for extension of the episiotomy.^[1]
• Digital rectal examination in every woman — with pill-rolling and pinch tests to assess the external and internal anal sphincters and to exclude an anorectal mucosal (buttonhole) tear. Anal sphincter injury cannot be excluded without it, and increased vigilance can double detection.^[1][6]
• Grade the injury out loud and have a second clinician confirm the grade, then document the anatomy pictorially. Refer to a more experienced clinician if uncertain.^[1]

(b) Classification and setting for repair (3 marks)

• Classification: a third-degree tear, grade 3b — more than 50 percent of the external anal sphincter thickness is torn, with an intact internal anal sphincter and intact anorectal mucosa. (1 mark) ^[1]
• The uncertainty rule: if I could not decide between less and more than 50 percent, I would classify to the higher degree — 3b, never 3a. (1 mark) ^[1]
• Setting: theatre, under regional or general anaesthesia, with good lighting, appropriate instruments and an assistant, performed by an appropriately trained clinician or a trainee under supervision. Anaesthesia is not for comfort alone — it allows retrieval of retracted sphincter ends and full definition of the injury. Repair in the delivery room only after discussion with a senior obstetrician; if bleeding is excessive, insert a vaginal pack and transfer to theatre promptly. (1 mark) ^[1]

(c) The repair (5 marks)

One mark per correctly named layer with its technique and suture; maximum five. No marks for "repair the sphincter" without specifics. ^[1][2]

Additional marks are available for: avoiding figure-of-eight sutures anywhere in the repair because they are haemostatic and cause tissue ischaemia; burying the surgical knots beneath the superficial perineal muscles to minimise suture migration; a swab and needle count; and a digital rectal examination after the repair to identify and remove any suture inadvertently passed through the anorectal mucosa.^[1]

(d) Postoperative management and follow-up (3 marks)

• Drugs: broad-spectrum antibiotics after the repair to reduce infection and dehiscence; a laxative such as lactulose for about 10 days, titrated to keep the stool soft but not loose; regular simple analgesia. Do not add a routine bulking agent — lactulose plus ispaghula husk produced more immediate postpartum incontinence than lactulose alone (32.86 percent versus 18.18 percent). (1 mark) ^[4][5][1]
• Immediate care: indwelling catheter while the block wears off, observation of the wound, pelvic floor physiotherapy referral, and written information about the injury sustained. (1 mark) ^[1]
• Follow-up and documentation: review at 6 to 12 weeks postpartum, ideally in a dedicated perineal clinic with access to endoanal ultrasonography and anal manometry, by a clinician with a special interest. Refer to a urogynaecologist or colorectal surgeon if she has incontinence or pain. Document the structures involved, the method of repair and the suture materials used, and counsel about the next birth: recurrence risk 5 to 7 percent, and elective caesarean offered if she is symptomatic or has abnormal imaging or manometry. (1 mark) ^[1][2]