An episiotomy is a surgical incision of the female perineum performed at the time of delivery to increase the diameter of the soft tissue pelvic outlet and facilitate a vaginal delivery. It is one of the most commonly performed surgical procedures in women in the United States, yet it is controversial.
For many decades the episiotomy was thought to provide protection to the female genital tract.1,2 It is thought to prevent perineal tearing by substituting a straight surgical incision for a ragged spontaneous laceration that may have a worse outcome after repair. It was also believed that an episiotomy resulted in decreased postoperative pain and improved healing when compared to a tear. These original beliefs have been challenged. There is a growing body of evidence demonstrating increased injury to the pelvic floor with the routine use of an episiotomy.3–6 A recent Cochrane database review of eight randomized controlled trials concluded that there is less posterior perineal trauma, less suturing, and fewer complications with a restrictive use versus the liberal use of an episiotomy.7 Currently, the evidence does not support a liberal or routine use of an episiotomy.8 These practice patterns are reflected in a steady decline in the use of an episiotomy from 1.6 million in 1992 to 716,000 in 2003.9,10
Nonetheless, there is a place for the episiotomy in modern obstetrics. The indications for an episiotomy today are based primarily on the clinical situation at the time of delivery. Another important reason to make an episiotomy is the prevention of a long and irregular spontaneous perineal laceration. The repair of a controlled surgical incision might be easier to repair, and the anatomical planes easier to recognize. Good clinical judgment is still the best guide to proceed or not with an episiotomy.11
The most critical area of the perineum is the distance from the vestibular fossa to the anus. This area is known as the pudenda, or more commonly as the perineal body. It is usually 3 to 4 cm in length in the nonpregnant woman.10,11 The perineal body is a complex fibromuscular mass into which many structures insert. It is bordered cephalad by the rectovaginal septum (Denonvilliers' fascia), caudad by the perineal skin, anteriorly by the posterior wall of the vagina, posteriorly by the anterior wall of the anorectum, and laterally by the ischial rami.12
The perineal body is the center of the hub of a wheel that includes the transverse perineal muscles, the capsule of the external anal sphincter muscle, and the bulbospongiosus muscle (Figure 132-1). The perineal body attaches to the ischial tuberosities and to the inferior pubic rami through the perineal membrane and superficial transverse perineal muscles. The bulbospongiosus muscles are located laterally to the introitus and deep to the labia majora. They insert ...