Forceps. Specialized forceps can be used to deliver the aftercoming head. Piper forceps, shown in Figure 28-11, or Laufe-Piper forceps may be applied electively or when the Mauriceau maneuver cannot be accomplished easily. The blades
FIGURE 28-11 Piper forceps for delivery of the aftercoming head. A. The fetal body is held elevated using a warm towel and the left blade of forceps is applied to the aftercoming head. B.The right blade is applied with the body still elevated. C. Forceps delivery of the aftercom ing head. Note the direction of movement shown by the arrow.
of the forceps are not applied to the aftercoming head until it has been brought into the pelvis by gentle traction, combined with suprapubic pressure, and is engaged. Suspension of the body of the fetus in a towel efectively holds the fetus up and helps keep the arms and cord out of the way as the forceps blades are applied.
Because the forceps blades are directed upward from the level of the perineum, some choose to apply them from a one-knee kneeling position. Piper forceps have a downward arch in the shank to accommodate the fetal body and lack a pelvic curve. This shape permits direct application of the cephalic curve of the blade along the length of the maternal vagina and fetal parietal bone. The blade to be placed on the maternal left is held in the provider's left hand. The right hand slides between the fetal head and left maternal vaginal sidewall to guide the blade inward and around the parietal bone. he opposite blade mirrors this application.
Once in place, the blades are articulated, and the fetal body rests across the shanks. The head is delivered by pulling gently outward and slightly raising the handle simultaneously. This rolls the face over the perineum, while the occiput remains beneath the symphysis until after the brow delivers. Ideally, the head and body move in unison to minimize neck hyperextension.
Modified Prague Maneuver. Rarely, the back of the fetus fails to rotate to the symphysis. The fetus still may be delivered using the modiied Prague maneuver. With this, two fingers of one hand grasp the shoulders of the back-down fetus from below while the other hand draws the feet up and over the maternal abdomen (Fig. 28-12).
FIGURE 28-12 Delivery of the aftercoming head using the modified Prague maneuver necessitated by failure of the fetal trunk to rotate anteriorly.
FIGURE 28-13 Duhrssen incision being cut at 2 o'clock, which is followed by a second incision at 10 o'clock. Infrequently, an additional incision is required at 6 o'clock. The incisions are so placed as to minimize bleeding from the laterally located cervical branches of the uterine artery. After delivery, the incisions are repaired as described in Chapter 41 (p.o763).
Head Entrapment. his emergency reflects either an incompletely dilated cervix or cephalopelvic disproportion. First, especially with a small preterm fetus, an incompletely dilated cervix can constrict around the neck and impede delivery of the aftercoming head. At this point, signiicant cord compression must be assumed, and time management is essential. With gentle traction on the fetal body, the cervix, at times, may be manually slipped over the occiput. If unsuccessful, then Diihrssen incisions may be necessary (Fig. 28-13). General anesthesia with halogenated agents or intravenous nitroglycerin is another option to aid lower uterine segment relaxation. As an extreme measure, replacement of the fetus higher into the vagina and uterus, followed by cesarean delivery, can rescue an entrapped breech fetus. This Zavaneli maneuver is classically performed to relieve intractable shoulder dystocia (Sandberg, 1988). However, case reports also have described its use for an entrapped aftercoming head (Sandberg, 1999; Steyn, 1994).