Disorders of placental invasion:
- Accreta – abnormal adherence of placenta to myometrium
- Increta – invasion of placenta into myometrium
- Percreta – invasion through serosa to adjacent structures
Incidence increasing with C-section rates ? 1 in 500 to 1 in 3000.
Main risk factor is prior C-section, and then implantation into the myometrial scar. Advanced age also a risk factor.
Risk is severe haemorrhage with foetal or maternal demise.
Haematuria may occur in 25 % of patients with bladder involvement, but patients are often asymptomatic.
Principles of management:
Pre-delivery:
- Early identification
- Best imaging available – MRI and ultrasound
- MDT formation – O&G, gynae-onc, MFM, paediatricians, IR, urology, gen surg, anaesthetics
- Specialised tertiary centre
- Appropriate counselling from urology prior regarding potential procedures
- Planning for elective procedure – generally around 34 weeks with steroid loading, generally Caesar-hysterectomy
- Cystoscopy to assess invasion can be considered, but do not biopsy due to excess bleeding
Operatively:
- Internal iliac balloon tamponade catheters can be placed
- Ureteric catheters reduce risk of ureteric injury
- Cell saver, blood available
- Internal iliac ligation or temporary aortic clamping is last resort for troublesome bleeding despite hysterectomy
- Attempts to separate uterus and bladder may cause excess bleeding, and cystotomy and partial cystectomy should be strongly considered – risk of VVF following.