In a time when repeat cesarean deliveries are becoming more frequent, it can be difficult to deliver an infant when the vertex is "floating" high out of the pelvis. Often, maximal fundal pressure is not adequate and the physician needs to use a vacuum device such as the Kiwi or forceps to complete the delivery.
Lyman G. Barton, MD, designed forceps with a hinged anterior blade for use in vaginal deliveries when the fetal head is arrested in the transverse position at the pelvic inlet.1,2 Although this type of operative vaginal delivery is no longer part of obstetric practice, we have found Barton's forceps to be useful in delivery when the fetal head is in the high transverse position, which frequently is encountered during a cesarean delivery. This is particularly true in repeat cesarean deliveries through a low transverse incision on a woman with a thick abdominal wall.
First described by Megison, Barton's forceps were successfully used in 300 cesarean deliveries without reported complications.3
The forceps have 2 fenestrated blades with a sliding lock. The posterior blade has a deep cephalic curve and the anterior blade has a hinge that extends the blade from the shank at about a 50° angle when in use (Figure 1).
Once the hysterotomy has been performed and the membranes are ruptured, the operator confirms the transverse position of the head. We recommend first placing the fixed posterior blade. This is in contrast to the procedure described for vaginal delivery in which the anterior (hinged) blade is wandered into position first.
To facilitate placement of the posterior blade, the operator places one hand under the head and slides the curved blade between the operator's fingers, moving the fetal head into position (Figures 2 and 3).
The anterior blade then is applied directly to the correct position on the cheek in front of the anterior ear. To achieve direct access, either the operator or the assistant inserts a finger into the upper open part of the hysterotomy, lifting gently to facilitate sliding the blade into place. This is easier to do if the blade is introduced from the patient's left side so that the shanks will lock without crossing. Once the shanks are locked, the deeper blade in the uterus is pulled back to the standard locked position.
At this point, the operator palpates the position of the forceps on the head to confirm that the sagittal suture is oriented transversely between the blades. Traction now is applied, without rotation, along the long axis of the mother. Extraction of the fetus is assisted by fundal pressure. While guiding the head out of the incision, the vertex may be flexed by digital pressure on the bones converging at the posterior fontanel.