Incision
Sites of both abdominal and uterine incisions need careful consideration when performing any CS for suspected PASD. A longitudinal skin incision which can initially be placed sub umbilically has advantages. It aids access both for adhesiolysis especially if the uterus is adherent to the anterior abdominal wall and for peripartum hysterectomy if required. It can also protect against inadvertent bladder injury if the bladder is drawn up. Extension offers access to the upper uterus should a classical or fundal uterine incision be chosen for placental avoidance, which itself allows placental retention should there be no signs of separation and uterine preservation is requested. However, a longitudinal skin incision may be less cosmetically acceptable and associated with more postoperative morbidity than a transverse wound.
A classical uterine incision on the upper segment may obscure the degree of placental separation leading to delay in controlling blood loss and difficulty in gaining access to the retracted muscle to repair the defect obligating a second transverse incision to be made for visualization, potentially increasing the risk of uterine rupture in any subsequent pregnancy. A transverse incision in the lower segment or isthmocele almost inevitably disturbs the placenta which can initially cause heavy bleeding and rules out placental retention. However, the use of a single uterine transverse incision through the previous scar has the advantage of allowing the placenta to be delivered in a systematic way under direct vision from its attachment on the posterior uterine wall first followed by removal from the neovascularized anterior wall while tracing the boundary of the sheared posterior myometrial defect prior to repair. This moderates the initial high blood loss from the neovascularised isthmocele associated with the more orthodox anterior placental separation and helps in the management of the often unrecognized bleeding from the posterior myometrial defect and the bleeding from the anterior inferior muscle close to the level of the internal os prior to repair.
We advocate entry through a pre-existing skin incision, usually transverse and suprapubic followed by a transverse incision through the upper third of the isthmocele above the level of the uterovesical fold through which the fetus and placenta are delivered. This avoids unnecessary dissection of the bladder and risk of renal tract injury as well as disruption of troublesome bridging vessels which run over the isthmocele and in the bladder serosa but does have the drawback of the patient being subject to a higher peripartum blood loss.