Episiotomy and Repair Technique

In an episiotomy, the perineum is incised with scissors or a scalpel as the infant’s head is crowning. Two types of episiotomy have been described: midline (median) and mediolateral (see the image below). ^[19] Generally, midline episiotomies are more commonly performed in the United States, whereas mediolateral episiotomies are more common in other parts of the world.

Incisions for mediolateral and midline (median) episiotomy. Image courtesy of Wikimedia Commons (Available at: https://commons.wikimedia.org/wiki/File:Medio-lateral-episiotomy.gif).

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In a risk assessment based on clinical anatomy, Garner et al found that midline incisions increased the risk of direct and indirect injury to the subcutaneous portion of the external anal sphincter. Mediolateral incisions posed a higher risk of injury to ipsilateral nerve, muscle, erectile, and gland tissues. ^[20]

The incision is generally repaired after delivery of the placenta is completed. Repair of an episiotomy should take place in a setting that contains appropriate instruments, exposure, and lighting.

Procedure

A midline episiotomy may be performed after adequate anesthesia has been confirmed. Protecting the fetal head during the procedure is of utmost importance. Generally, the index and middle fingers are inserted into the vagina between the fetal head and the perineum. This maneuver provides space for making the incision.

A vertical incision is made in the midline of the perineum from the posterior fourchette toward the anus. Most commonly, the incision is made just before delivery of the fetal head, at the time when the perineum is thinned and stretched. At present, however, the evidence is insufficient to establish any particular time as the most appropriate for performing an episiotomy.

Repair

Repair of any perineal laceration, including episiotomy, serves the following 2 important functions:

• Hemostasis

• Tissue reapproximation for lacerated vaginal mucosa, soft tissue, and muscle

Accordingly, delivering providers must have a comprehensive understanding of perineal anatomy.

Various types of sutures have been used for episiotomy repair, and only limited evidence suggests the superiority of one material over another. Both chromic catgut and synthetic materials have been used successfully, and many providers now prefer braided standard or rapid-absorption polyglycolic acid sutures (typically Vicryl, Polysorb), given their minimally reactive nature. Additionally, monofilament sutures with more rapid absorption, such as Caproysn, may be used for perineal laceration repair.

Generally, the smallest-diameter suture that provides adequate tensile and knot strength for the surgical task should be used. In most instances, 2-0 and 3-0 sutures are suitable for reapproximation and repair of soft tissue in an episiotomy repair. For optimal visualization, repair should take place in a labor and delivery room or an operating room with appropriate lighting.

The ensuing description focuses on a standard episiotomy repair without extension, which is equivalent to a second-degree perineal laceration. A thorough examination of the perineum should always be performed to evaluate for extension to a third- or fourth-degree laceration. Further information regarding repair of third- and fourth-degrees lacerations is available in several standard obstetric references. ^{[18, 21, 22, 23]}

The repair is initiated by placing a suture approximately 1 cm proximal to the apex of the laceration within the vagina. The suture is secured with a knot, and the repair is continued in a continuous fashion (locked or nonlocked) to the level of the hymenal ring. The vaginal mucosa and submucosal tissue must be sufficiently reapproximated with the continuous suture, and all dead space must be closed. Careful attention must be directed to preventing sutures from passing deep enough to traverse the rectal mucosa.

Next, the hymen is reapproximated with the suture in a nonlocked fashion. This suture is then tucked through the hymenal ring posterior to the perineal body for the remainder of the repair. At this point, the muscular tissue of the perineal body is reapproximated; this includes an interrupted “crown stitch” of the bulbocavernosus muscles and interrupted or running sutures of the transverse perineal muscles.

The suture is then run posteriorly to the posterior apex of the incision to reapproximate the remainder of the perineal body. This is followed by a subcuticular skin closure run anteriorly to the introitus. Finally, the suture is secured with a knot inside the hymenal ring.

Procedure

As with a midline episiotomy, the data are insufficient to determine the optimal time for performing a mediolateral episiotomy. Most surgeons recommend making the incision immediately before delivery. The index and middle fingers are placed into the vagina between the fetal head and the perineum.

An incision is begun at the posterior fourchette and continued downward at an angle of at least 45° relative to the perineal body. The angle of the incision may approach 90° (perpendicular to the posterior fourchette) if the perineum is significantly stretched by the fetal head, so that upon relaxation of the perineum the angle will approach 45°. The incision can be performed on either side and is generally 3-4 cm in length.

The anatomic structures involved in a mediolateral episiotomy include the vaginal epithelium, transverse perineal muscle, bulbocavernosus muscle, and perineal skin. A deep or large mediolateral episiotomy may expose the ischiorectal fossa.

Repair

First, the delivering provider should examine the extent of the laceration after delivery, carefully evaluating for possible extension to third- or fourth-degree laceration. Either 2-0 or 3-0 sutures (of the same materials as used for midline episiotomy) may be used for the repair.

With 2 fingers placed in the vagina for retraction, the apex of the episiotomy site is identified, and a suture is secured approximately 1 cm proximally. The submucosal tissue and vaginal mucosa are reapproximated in a continuous fashion (either nonlocked or locked). A deep episiotomy or laceration may require additional submucosal sutures for appropriate tissue reapproximation and closure of dead space.

The bulbospongiosus muscle generally must be repaired. The fascial sheath of the muscle on both sides of the incision should be repaired in an interrupted fashion before closure of the skin, which is performed with a subcuticular stitch. Sutures should be placed perpendicular to the angle of the incision to prevent anatomic distortion of the perineum and vaginal opening.

Bleeding

Bleeding is one of the most common complications of episiotomy. The perineum and surrounding tissues have an extensive vasculature, and the blood supply to these areas is increased by the physiologic changes of pregnancy and labor.

Immediately after delivery, the episiotomy site should be inspected for bleeding. Because episiotomy is usually performed at the time of crowning, it sometimes happens that an incision is made through blood vessels that have been rendered invisible by compression from the fetal head. Inspection should include an evaluation for arterial bleeding, which may require suture ligation.

Typical episiotomy site bleeding can generally be controlled with conservative measures (eg, compression) while the repair is being performed to achieve hemostasis. Because of muscle involvement, a mediolateral episiotomy may give rise to more bleeding than a midline episiotomy. Careful inspection prior to and during the repair is required to assess for hematoma formation, which can cause significant maternal morbidity in the rare instances in which deep hematomas dissect proximally toward the upper vagina and the broad ligament.

Extension to higher-order lacerations

Another common complication of episiotomy is extension to higher-order perineal lacerations. Among primiparous women, the reported risk of third- or fourth-degree lacerations is 1% without an episiotomy, 9% with a mediolateral episiotomy, and 20% with a midline episiotomy. ^[24] Performance of a midline episiotomy may be the biggest risk factor for extension of a laceration into the rectum. ^{[8, 9]}

Close inspection and examination of the incision after delivery is of utmost importance; failure to identify an extension or higher-order laceration can result in infection, dehiscence, fecal incontinence, or fistula formation. Various perineal techniques (eg, warm compresses) may also be used in an effort to reduce perineal trauma. ^[25]

Infection

Because the site of the episiotomy is heavily colonized by bacteria and frequently contaminated by fecal matter during the process of delivery, a significant risk of infection exists. Infection generally manifests within the first week following delivery. Signs and symptoms of episiotomy infection include fever, focal tenderness at the wound site, and purulent or malodorous drainage.

Most episiotomy infections are localized and respond to appropriate wound care and oral antibiotics. If an abscess forms, drainage may be required, or spontaneous wound breakdown may ensue. In rare cases, necrotizing fasciitis may occur; this can be life-threatening if not appropriately evaluated and treated.

Routine antibiotic prophylaxis is not recommended after an episiotomy or repair of an obstetric laceration. However, infection increases the risk of perineal repair breakdown, particularly for higher order (third- or fourth-degree) lacerations. ^[26] Because breakdown of higher order lacerations may result in incontinence of stool or flatus, sexual dysfunction, or rectovaginal fistula, the use of prophylactic antibiotics in this setting has been evaluated.

Data from a single randomized trial suggests that administration of a second-generation cephalosporin (cefoxitin or cefotetan; if penicillin allergy, clindamycin) decreases the risk of perineal wound complications. ^[27] However, this study had a high rate of loss to follow-up (27%), and its findings have not been replicated in other studies.

Given the lack of evidence following a meta-analysis of data from the Cochrane Pregnancy and Childbirth Group's trial register, Buppasiri et al indicated that additional data are necessary before routine antibiotic prophylaxis for third- or fourth-degree perineal tears is recommended. ^[28] The American College of Obstetricians and Gynecologists (ACOG) also does not recommend universal prophylaxis due to lack of evidence, ^[29] but the Royal College of Obstetricians and Gynaecologists (RCOG) recommends routine prophylaxis owing to the severity of the outcomes following infection. ^[30]

Dehiscence

Breakdown of an episiotomy repair is infrequent (< 2% of cases of higher-order lacerations) but may be a particularly challenging complication for patients and providers. ^[31] Dehiscence can occur with or without wound infection. Small defects may heal spontaneously without closure; however, many defects require surgical closure.

Historically, delayed closure (2-3 months after delivery) was performed. Over the past 20 years, early closure has been reported to represent an appropriate and successful approach. ^{[32, 33, 34]} . Measures such as debridement or parenteral antibiotic therapy may be necessary before wound closure.