Symphysiotomy is the artificial division and separation of the
pubic symphysis in order to facilitate vaginal delivery. This is
not to be confused with a pubiotomy, or the severance of the pubic bone
a few centimeters lateral to the symphysis, for the same purpose.
First performed in the seventeenth century, it is indicated in cases
of cephalopelvic disproportion and may be a life-saving alternative
to cesarean delivery.1 The reported success rate of this
procedure is about 80 percent when performed appropriately.2
The procedure itself is well described and can be accomplished
under local anesthesia.2 Early reports of urologic and
orthopedic complications led to its decline and lack of acceptance
in modern obstetrical practice despite initial successes.3 Symphysiotomy
is performed quite regularly and successfully in developing countries
where medical conditions are not as favorable as in the United States.4
Indications for a symphysiotomy include breech delivery, cephalopelvic
disproportion, and for the relief of shoulder dystocia.1,5,6 Each
of these conditions poses significant potential risks to mother
and child, even under optimal conditions. Emergency Physicians should
be familiar with the indications and technique of symphysiotomy
as expeditious delivery is vital in these scenarios.
The pelvis is composed of four bones: the sacrum, the coccyx,
and the two innominate bones. Each innominate bone is made up of
the fused ischium, ilium, and pubis. The innominate bones are connected
at the sacrum by the sacroiliac ligaments and at the pubic symphysis
by the superior and arcuate pubic ligaments.7 Together
they determine the size and shape of the pelvis. The fetus
assumes positions during labor that are primarily determined by
the conformation of the mother’s pelvis.8
The pelvis is divided into a true pelvis and a false pelvis.
They are separated by the linea terminalis, an anatomic boundary
formed by the pelvic brim (superior pelvic aperture). The true pelvis lies
below the linea terminalis and is the more relevant portion in delivery.9 Dense
ligaments hold the walls of the true pelvis together. The posterior
wall is the anterior surface of the sacrum and coccyx. The lateral
boundaries are formed by the inner surface of the ischial bones
as well as the sacrosciatic notches and ligaments. The ischial spines
can be readily palpated during the vaginal or rectal examination.
They serve as important landmarks in determining to which level
the presenting part has descended into the true pelvis. The true
pelvis is bounded anteriorly by the pubic bones, the ascending superior
rami of the ischial bones, and the obturator foramina.
The ligaments of the pubic symphysis and the sacroiliac ligaments
allow mobility and contribute to the increase in pelvic diameter
during pregnancy.8 The sacral nerves, the coccygeal nerves,
and the pelvic portion of the autonomic nervous system innervate
the pelvis. The important pudendal nerve arises from the sacral
plexus and accompanies the internal pudendal artery. ...