Treatment of posterior face presentations

Abstract

The treatment of 8 cases of posterior face position in labor and of one before the onset of labor is described. The latter was converted to an occiput presentation by the abdominal maneuver of Schatz.During labor four of these positions were converted by the Thorn maneuver to the occiput anterior and safely delivered. Two others were rotated to a mentum anterior and delivered as such with forceps. One patient was delivered by a low flap cesarean section, and one by a supravesical extraperitoneal cesarean section. There were no maternal deaths or stillbirths. The two infants delivered by forceps in the mentum anterior position died during the neonatal period apparently to the effects of birth trauma.Version was not attempted in this series primarily because of (1) a contracted or borderline pelvis; (2) a tight, thin uterus with membranes long ruptured; and (3) an incompletely dilated cervix.The etiology of this abnormal position was not always clear but one constant finding seemed to be relative disproportion between the size of the infant and pelvis. The pelvic asymmetry was demonstrated by the three small android pelves which we were able to check by x-ray, and the fetal factor by one large eleven-pound child and by one small five-pound, twelve-ounce child in a large multiparous woman. Multiparity and relaxed abdominal walls did not seem to be important, as there were four young primiparas with firm musculature and only two had had more than two children. A differential between primary and secondary dolichocephaly could not be established, but it is interesting to note that of the 6 babies whose head measurements were recorded, 5 had an occipitofrontal diameter of 12.5 cm. or greater. The exception was the small child mentioned above whose occipitofrontal measurement was 9.5 cm.Early diagnosis and accurate determination of size and shape of pelvis are essential to the proper conduct of this type of dystocia. X-ray pelvimetry is of assistance but not always conclusive. Where definite cephalopelvic disproportion exists, cesarean section is the method of choice, except that in the cases where labor is far advanced the choice lies between extraperitoneal section, hebosteotomy, and craniotomy.In the borderline case, conversion to the occiput anterior is the safest course. If descent does not then follow, forceps delivery must be added to the three procedures mentioned in advanced cases. In patients with ample pelves, spontaneous rotation to the mentum anterior is the rule. We believe that this explains the constant finding of small pelves in this group of persistent posterior face presentations. This also raises the question of the advisability of rotation to the mentum anterior and forceps delivery in cases with relatively contracted pelves. Extraperitoneal cesarean section and hebosteotomy are definitely less harmful to the infant.