Indications. This incision is usually avoided because it encompasses the active upper uterine segment and thus is prone to rupture with subsequent pregnancies. Some indications stem from diiculty in exposing or safely entering the lower uterine segment. For example, a densely adhered bladder from previous surgery is encountered; a leiomyoma occupies the lower uterine segment; the cervix has been invaded by cancer; or massive maternal obesity precludes safe access to the lower uterine segment. A classical incision is also preferred for placenta previa with anterior implantation, especially those complicated by placenta accrete syndromes. In extreme cases of this, the typical classical hysterotomy may be placed even higher in the uterine body or posteriorly to avoid the placenta. As such, fetuses with cephalic presentation are then delivered in a manner similar to total breech extraction (Chap. 28, p. 548).
In other instances, fetal indications dictate the need. Transverse lie of a large etus, especially if the membranes are ruptured and the shoulder is impacted in the birth canal, usually necessitates a classical incision. A fetus presenting as a back-down transverse lie is particularly di.cult to deliver through a transverse uterine incision. In instances when the fetus is very small and breech, a classical incision may be preferable (Osmundson, 2013). In such cases, the poorly developed lower uterine segment provides inadequate space for the manipulations required for breech delivery. Or, less commonly, the small fetal head may become entrapped by a contracting uterine fundus following membrane rupture. Last, with multiple fetuses, a classical incision again may provide suitable room for extraction of fetuses that may be malpositioned or preterm (Osmundson, 2015).
Uterine Incision and Repair. A vertical uterine incision is initiated with a scalpel beginning as low as possible and preferably within the lower uterine segment (Fig. 30-11). If adhesions, insu.cient exposure, a tumor, or placenta percreta preclude development of a bladder flap, then the incision is made above the level of the bladder. Once the uterus is entered with a scalpel, the incision is extended cephalad with bandage scissors until it is long enough to permit delivery of the fetus. With scissor use, the fingers of the nondominant hand are insinuated between the myometrium and fetus to prevent fetal laceration. As the incision is opened, numerous large vessels that bleed profusely are commonly encountered within the myometrium. The remainder of fetal and placental delivery mirrors that with a low transverse hysterotomy.
For incision closure, one method employs a layer of 0-or no. 1 chromic catgut with a running stitch to approximate the
FIGURE 30-11 An initial small vertical hysterotomy incision is made in the lower uterine segment. Fingers are insinuated between the myometrium and fetus to avoid fetal laceration. Scissors extend the incision cephalad as needed for delivery. (Reproduced with permission from Johnson DD: Cesarean delivery. In Yeomans ER, Hoffman BL, Gilstrap LC III, et al (eds): Cunningham and Gilstrap's Operative Obstetrics, 3rd ed. New York, McGraw-Hili Education, 201o7.) deeper length of the incision (Fig. 30-12). he outer layer of myometrium is then closed along its length with similar suture and with a running suture line. To achieve good approximation and to prevent the suture from tearing through the myometrium,
FIGURE 30-12 Classical incision closure. The deeper half (left) and superficial half (middle) of the incision are closed in a running fashion. The serosa is then closed (right). (Reproduced with permission from Johnson DD: Cesarean delivery. In Yeomans ER, Hoffman BL,