Delivery of Placenta
A low lying placenta may be situated within the isthmocele or attached to the previous scar depending on its level (within or above the endocervical canal). If the placenta is not adherent, it will separate spontaneously with or without uterotonics. If it is adherent, manual removal will be required. Regardless of method of placental delivery, both leave a non-retractile isthmocele which may be bleeding profusely from the retracted muscle rings at its boundary and the numerous bridging vessels lying in the serosa. We recommend a posterior rather than an anterior starting approach for the manual removal of the placenta to reduce the risk of bleeding from the aberrant vessels present anteriorly where the tissue planes are obscured. This has the added advantages of reducing risk of bladder injury and helping in identification of the posterior myometrial defect as described in the original method.
If manual removal is required, we advocate the following steps:
1 . After uterine entry the operator’s right hand is inserted through the incised isthmocele and directed towards the upper border of the placental attachment on the posterior uterine wall (Fig. 1) from where detachment is initiated, working laterally, bilaterally, to expose the posterior uterine wall defect (Fig. 2).
2. The exposed retracted inferior and superior posterior muscles are then grasped with Green Armytage clamps (Fig. 3). In some instances, the sheared posterior defect may be large and the inferior myometrial boundary difficult to identify. Recognition may be aided by the assistant’s right hand raising the outer aspect of the uterus below the utero sacral ligament facilitating application of the Green Armytage clamps to the lower posterior retracted muscle within.
3. Once the lateral aspects of the placenta are reached the operator’s left index and middle fingers are inserted into the endocervical canal to the anterior fornix (Fig. 4) to lift the cervix (Fig. 5) and allow the retracted anterior inferior muscle edges to be identified and clamped, before detaching any residual attached placenta. This muscle ring is normally found at the level of the internal cervical os and needs to be isolated prior to application of clamps to avoid damage to the bladder base. Once the anterior ring of inferior muscle has been caught securely, the bleeding starts to slow and the bladder can be separated safely from the lower segment of the uterus working from the lateral aspects medially.
4. The myometrial defect, the boundaries of which are shown in Figure 6, is then repaired as previously described. (10). Success of this technique involves correct recognition of the retracted muscles at the boundary of the myometrial defect and repair of the muscle edges. As the posterior myometrial defect is closed and the uterine angles are secured the bleeding slows further allowing completion of the repair. Any redundant fascia forming the isthmocele, if not already ruptured, is incorporated into the anterior repair to build up the anterior uterine wall at the site of the scar and reduce the bleeding from the overlying aberrant vessels which can be difficult to control.