Chapter 137. Symphysiotomy

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 approximately 80% 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 Presently, a symphysiotomy is performed quite regularly and successfully in rural areas of the world where medical resources are not as abundant as in developed countries.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. It enters the perineal region via the lesser sciatic foramen and around the sacrospinous ligament to supply the muscles of the perineum.7 Anesthesia to the perineal region can be accomplished by performing a pudendal nerve block.

Symphysiotomy is indicated in any difficult delivery in the presence of fetal distress, when labor is obstructed, and when an Obstetrician is not immediately available. It has traditionally been reserved for complicated breech deliveries or cases of cephalopelvic disproportion in which the fetal head is presenting vertex and at least one-third of the fetal head has entered the pelvic brim and cervical dilatation is no more than 7 cm.1 Symphysiotomy has been advocated more recently for the relief of intractable shoulder dystocia.5,6

There are no absolute contraindications to performing a symphysiotomy. Some authors have recommended limiting symphysiotomy to mothers weighing between 50 to 80 kg and a fetus with an estimated mass of 2700 to 3700 g.10,16 Other relative contraindications include the presence of maternal spinal deformities, hip deformities, pelvic deformities, and gross obesity.10 Symphysiotomy has been performed after a prior cesarean section without added complications despite concerns regarding the safety of symphysiotomy in the presence of a previous cesarean scar.10

• Local anesthetic solution
• Povidone iodine or chlorhexidine solution
• Sterile gloves and gown
• Face mask and cap
• Urethral catheter set
• Sterile drapes
• #10 scalpel blade on a handle
• Mayo scissors
• Finger guard
• Hemostats
• Sterile gloves
• Neonatal resuscitation equipment
• Infant warmer

Explain the risks, benefits, and potential complications to the patient and/or their representative. Obtain an informed consent to perform this procedure if time allows. Place the patient in the lithotomy position with the thighs separated no more than 90°. This position is necessary to prevent undue strain on the sacroiliac joints. Two assistants should be available to maintain proper maternal leg positioning. Insert a Foley catheter into the bladder (Chapter 142).

Prepare the surgical area. Shaving the mons pubis is optional. Apply povidone iodine or chlorhexidine solution onto the skin overlying the pubic symphysis and surrounding area and allow this to dry. The Emergency Physician must perform this procedure using aseptic technique. This includes wearing sterile gloves, a sterile gown, a cap, and a face mask. Apply sterile drapes to form a sterile field. Infiltrate the anterior and inferior aspects of the pubic symphysis and the surrounding skin with 5 to 10 mL of local anesthetic solution to anesthetize the pubic symphysis. Leaving the needle in place may be useful in identifying the pubic symphysis joint. Equipment for infant resuscitation should be readily available, as with all deliveries. Notify the neonatal resuscitation team and a Neonatologist of the impending procedure and delivery.

Place the nondominant index finger into the vagina and against the posterior aspect of the pubic symphysis (Figure 137-1). Advance the finger approximately 2 to 3 cm beyond the superior aspect of the pubic symphysis to displace the bladder and urethra. Do not move this finger until the procedure is complete.

Grasp the scalpel in the dominant hand with the cutting edge of the blade facing you (Figure 137-2). The scalpel blade must be kept in a strict midsagittal plane and perpendicular to the skin overlying the pubic symphysis. Resting the hypothenar eminence of the dominant hand against the patient's pubic ramus will help maintain fine control of hand and finger movements.2

Make a midline stab incision 1 cm below the upper edge of the pubic symphysis (Figure 137-3). Very little resistance should be met as the scalpel blade pierces the hyaline cartilage of the pubic symphysis if the scalpel is in the midline. Carefully and slowly advance the scalpel blade until the tip is just felt through the anterior vaginal wall. Resistance is usually a result of lateral deviation of the scalpel blade against the pubic bones. Withdraw the scalpel blade 2 to 3 mm and re-advance it in the midline. Use extreme caution so that the scalpel does not lacerate the vagina, the urethra, or the finger.

Lower the handle of the scalpel blade cephalad, toward the abdomen, using the upper portion of the pubic symphysis as a fulcrum. Cut through the lower half of the pubic symphysis, dividing the cartilage and associated ligaments. Remove the scalpel blade and reinsert it with the cutting edge in the opposite direction and facing the cephalad. Repeat the same maneuver but with the scalpel handle lowered caudally to divide the upper portion of the pubic symphysis, thereby completing the separation.

Use the nondominant index finger to confirm complete separation of the pubic symphysis. The symphysiotomy is complete when the index finger pressing through the vaginal wall can fit into the space between the pubic symphysis. Reinsert the scalpel to complete the division if any ligaments or cartilage remains. The entire procedure should take 2 to 3 minutes. A variation of the above technique involves simply dividing the pubic symphysis in a single step by a repeated slow stabbing motion.

Once the symphysiotomy is completed, delivery of the infant should follow. Delivery of the infant usually requires more downward traction than is usually necessary.

Deliver the placenta and control any postpartum hemorrhage. Carefully return the mother to the supine position with the thighs in normal anatomic position. Close the skin and subcutaneous tissue with simple interrupted 4-0 nylon sutures. Some authors have recommended binding the knees for 12 to 48 hours to prevent inadvertent abduction or external rotation of the hips.11 Admit the patient to the hospital for observation and monitoring of any potential complications. Leave the Foley catheter in place until any bleeding resolves or the patient begins to walk. Patients may begin ambulation with assistance between the second and fifth days. They should be warned against any unusual straining or heavy lifting.

Experience and careful case selection appear to be the most important factors in determining outcome and morbidity associated with this procedure.2 While symphysiotomies do not cause maternal death, immediate complications include bladder lacerations, urethral lacerations, subcutaneous bleeding, and urinary incontinence.10,11 Some patients develop gait instability immediately after the operation that tends to be transient and does not appear to affect subsequent pelvic stability.13

Lacerations to the Emergency Physician's fingers are a significant concern.12,15 Prevent lacerations by using the utmost of care and slowly transect the cartilage and ligaments of the pubic symphysis. The nondominant hand should be double-gloved at a minimum.12 The use of a Kevlar glove that is resistant to scalpel injury may also be used.15 A third option is to apply a malleable splint over the palmar aspect of the index finger before double gloving.12

Long-term complications include, but are not limited to, stress urinary incontinence, recurrent urinary tract infections, sepsis, and vesicovaginal fistulas.14 Vaginal fistulas are frequently due to nonplacement of a Foley catheter during the procedure.3 This important step should never be omitted. The effect of a symphysiotomy on subsequent pregnancies has not been studied in detail. However, the limited data available suggest that a symphysiotomy permanently enlarges the pelvis so that subsequent vaginal deliveries are in fact easier.13

In developed countries, modern surgical techniques and obstetrical advances have diminished the practice of symphysiotomy. However, it still remains a simple and safe method to overcome the common and lethal problems of cephalopelvic disproportion, shoulder dystocia, and breech deliveries. Complications are uncommon when performed correctly. Emergency Physicians can master this procedure.12 A symphysiotomy is a viable and potentially lifesaving option for those who may be working outside the confines of a well staffed and equipped hospital.