Pelvic floor after childbirth — structured SAQ (15 marks)

(a) Sultan grading (4 marks)

One mark for the principle, then one mark per grade defined (max 4). ^[1][2]

• The Sultan classification grades third- and fourth-degree (obstetric anal sphincter) injuries by the structures involved.
• 3a — less than half the thickness of the external anal sphincter (EAS).^[1]
• 3b — more than half the thickness of the EAS.
• 3c — involvement of the internal anal sphincter (IAS).
• 4th degree — full-thickness disruption of EAS and IAS with involvement of the anorectal mucosa.^[1][2]

A reasoning mark for stating that accurate grading matters because anal incontinence incidence rises with grade (3a about 22.4% to fourth degree about 28.6% in the Okeahialam network meta-analysis).^[2]

(b) Immediate management (4 marks)

One mark per point, maximum four. ^[1][3]

• Escalate the environment: transfer to a properly lit theatre with adequate anaesthesia (regional or general), lithotomy position, an assistant and good exposure — do not repair on the delivery bed.^[3]
• Call for senior help: consultant or perineal trauma specialist to supervise or perform the repair.^[3]
• Repair technique: for the EAS, use the overlap technique where feasible (the Cochrane review found overlap associated with less faecal urgency at 12 months, RR 0.12, 95% CI 0.02 to 0.86); repair the IAS separately with interrupted absorbable sutures.^[3]
• Antibiotic prophylaxis and a stool softener or laxative to prevent constipation straining; catheterise if regional anaesthesia or impaired voiding.^[3]

(c) Post-repair care bundle and follow-up (4 marks)

One mark per point, maximum four. ^[2][3]

• Antibiotics and laxatives for the immediate post-repair period, with adequate analgesia.^[3]
• Pelvic floor muscle training (PFMT): start once pain allows, ideally supervised and individualised by a pelvic floor physiotherapist; PFMT is recommended as first-line for postpartum urinary incontinence (Cochrane), though anal incontinence is not proven to respond.^[3]
• Perineal clinic review at 6 to 12 weeks: assess continence, wound healing, sexual function and psychological wellbeing.^[2]
• Endoanal ultrasound for any persistent symptoms or a large residual defect; counsel on future mode of birth using continence status and imaging.^[2]

(d) Pelvic floor dysfunction despite an intact sphincter (3 marks)

Three marks for the neurological mechanism and the evidence. ^[4]

• Pelvic floor dysfunction after childbirth is not only a sphincter (mechanical) problem — it is also a neurological one. The pudendal nerve is stretched and compressed during descent of the fetal head and a prolonged second stage, causing partial denervation of the pelvic floor muscles.^[4]
• Allen's 1990 neurophysiological study of 96 nulliparae found EMG evidence of re-innervation after vaginal delivery in 80% — proof that partial denervation occurs in most first-time mothers.^[4]
• The degree of nerve damage tracked a long active second stage and heavier babies, while forceps delivery and perineal tears did not; in a few women the denervation was severe and associated with urinary and faecal incontinence. So a woman with an intact sphincter can still develop prolapse and incontinence from nerve injury alone.^[4]