Opening the skin and sheath with monopolar diathermy pencilette
SAC technique: Large curvi-linear transverse incision in the rectus sheath (monopolar diathermy with protection of the underlying muscle provided by Roberts).
SAC technique: The sheath is carefully dissected away from the recti muscles to the level of the umbilicus
SAC technique: After vertical division of the inner rectus sheath layer (midline) we use a careful 'cold' opening approach to the peritoneum
Choice of Abdominal Incision
The choice of skin incision should be individualised to each woman, taking account of all past surgical history (potential for adhesions) as well as the degree of PAS suspected, extent of surgical intervention anticipated, gestation, BMI and size of panus.
A 15-20cm transverse incision, made 2-4cm above the pubic symphysis, may be adequate if the antenatal suspicion of PAS is not high.
Alternatively, modified Cherney or Maylard approach (with or without muscle cutting) may improve the pelvic and abdominal access. This is achieved via a transverse skin incision by transecting the rectus muscles either at, or 3-8cm above, their insertion onto the pubic symphysis respectively.
Traditionally a midline laparotomy has been recommended.
Advantages of vertical incision
An easily extendable and less haemorrhagic incision
Reduced incidence of superficial nerve injury
Disadvantages of vertical incision
Increased wound dehiscence
Increased risk of subsequent incisional hernia
Increased infection rate
Longer operative time
The SAC Incision
The SAC technique achieves excellent surgical access for the vast majority of cases via a novel hybrid transverse/vertical abdominal entry. The modification from Maylard is not cutting the muscles thereby decreasing the morbidity of the incision. Adequate access is gained by a large curvilinear incision in the rectus sheath and then reflecting the sheath off the recti muscles to the level of the umbilicus and vertically dividing the inner sheath midline.
SAC abdominal entry
1. A curvi-linear transverse incision 25-30cm long from anterior superior iliac spine (ASIS) to ASIS, passing 5-6 cm above the pubic symphysis in the centre line is made in the skin.
2. The subcutaneous layers are opened in the routine manner (with monopolar diathermy to reduce blood loss).
3. A large curvi-linear transverse incision is made in the external layer of the rectus sheath.
4. The abdominal wall muscles are then carefully reflected off the inner layer of the rectus sheath.
5. Vertical division of the inner rectus sheath layer (midline) starting from the arcuate ligament and extending up to the umbilicus allows access to the uterine fundus.
Advantages of SAC incision
Less risk of incisional hernia
Disadvantages of SAC incision
Potential risk of needing vertical extension in an emergency
Risk of nerve trauma if operator is not fully aware of the anatomy
Regardless of choice of skin incision made, we recommend performing the initial skin cut with cold scalpel; followed by the use of monopolar energy (settings 35:35 - blend:spray) to open the abdomen in layers with haemostatic control; before reverting to cold opening of the peritoneum