Stress urinary incontinence and midurethral sling — structured SAQ (15 marks)

(a) Diagnosis, mechanism and urodynamic subcategories (4 marks)

One mark per correct element; up to two marks for the diagnosis, one for the mechanism, one for the urodynamic subcategories.[1]

• Diagnosis: Stress urinary incontinence (SUI) — involuntary loss of urine on effort, exertion, coughing or sneezing, confirmed by the positive cough stress test.[1]
• Mechanism: weakness of urethral support (urethral hypermobility) or weakness of the urethral closure mechanism itself (intrinsic sphincter deficiency). The integral theory of Petros and Ulmsten (1990) frames the mid-urethra as the critical zone; a midurethral sling restores the pubourethral backboard.[1]
• Urodynamic subcategories to exclude:
  • Urethral hypermobility (Q-tip 30° or more; normal MUCP) — managed by either RP or TO sling.[1]
  • Intrinsic sphincter deficiency (ISD) (VLPP under 60 cm H₂O or MUCP under 20 cm H₂O) — favours the retropubic approach because TO fails more often in ISD (Ford 2016 meta-analysis).[6]
  • (Bonus point if the candidate names detrusor overactivity as the alternative diagnosis to exclude with mixed or pure urge components.)

(b) Conservative options already tried and the surgical next step (5 marks)

One mark per correct conservative option already deployed; two marks for naming the next surgical step and quoting the position statement.[1][2]

• Lifestyle and behavioural measures — weight loss for BMI 32 (acknowledged contributor), reduction in caffeine and total fluid loading, smoking status, treatment of chronic cough and constipation. Discussed and attempted.[2]
• Supervised pelvic floor muscle training (PFMT) — 14 weeks of supervised PFMT with a women's health physiotherapist, completed before surgical referral. The Cochrane 2018 numbers justify this minimum trial: 56% cure with PFMT vs 6% with no treatment for SUI (RR 8.38, 95% CI 3.68 to 19.07; 4 trials, 165 women; high-quality evidence).[2]
• Continence pessary (incontinence ring or dish) — a non-surgical option she has not yet tried. The Pelvic Floor Disorders Network trial showed 92% successful pessary fitting in women with SUI and POP-Q stage 2 or less. Worth a brief trial before surgery, especially given she would prefer to avoid an operation.
• Surgical next step: midurethral sling (MUS) — the operation of choice for female SUI in Australasia when conservative measures fail.
• RANZCOG statement: Position statement on midurethral slings (C-Gyn 32, July 2020, amended March 2022). Recommendation 1 (Evidence-based, Grade A): "MUS surgery is a recommended surgical procedure for SUI in routine cases." The Good Practice Point requires local credentialling, written information (including from the ACSQHC), audit and patient-reported outcomes.[1]

(c) Retropubic vs transobturator — approach, complications, preferred women (4 marks)

One mark per correct comparison element; max four.[1][4]

• RP preferred (routine): ISD; any woman in whom you want the routine option (C-Gyn 32, ACSQHC).[1]
• TO preferred: extensive previous abdominal surgery where retropubic adhesions raise the bowel/vascular injury risk; inability to cease anticoagulation (lower visceral injury risk); ISD is the contraindication to TO. C-Gyn 32 specifies TO only in exceptional circumstances with multidisciplinary discussion.[1]

(d) Consent — complications to discuss, with headline numbers (2 marks)

One mark per correct complication with its headline figure.[1]

• Mesh exposure / erosion: approximately 2% for both RP and TO.[1]
• Chronic pain: up to 5% (Federal Court of Australia ruling Gill v Ethicon 2019).[1]
• Severe pain requiring sling removal: approximately 1 in 150 (around 0.7%).[1]
• Voiding dysfunction needing sling loosening or division: approximately 0.6% (Laurikainen 2006, 9,040 TVTs nationwide) — and she must be told that sling release can leave her with recurrent SUI.[5]
• De novo urge incontinence or worsening of overactive bladder symptoms: 5–15%.[1]
• Bleeding; damage to bladder and urethra; bowel and major vessel perforation; recurrence of SUI after sling release; dyspareunia (and partner symptoms); failure of primary procedure. [1]
• Audit: her case will be logged on the UGSA database, the IUGA database, or the Australian Pelvic Floor Procedures Registry; adverse events reportable to the TGA in Australia or MEDSAFE in New Zealand.[1]