For the obstetric patient, several factors influence the surgeon’s choice of abdominal incision and closure. Patient elements include the surgical indication, the urgency for operative intervention, and comorbid preoperative conditions. Specific to the wound, the presence of prior abdominal scars and circumstances affecting wound integrity also direct appropriate incision selection. Ideally, incisions are chosen to provide appropriately rapid entry, adequate exposure, and closure that will reduce the likelihood of infection or dehiscence.

An intelligent choice of incision depends on a thorough understanding of abdominal wall anatomy. First, distribution of anterior abdominal wall vessels and nerves can affect postoperative healing and function. Knowledge of their location enables surgeons to minimize injury risk to these. Moreover, abdominal wall characteristics such as the direction of muscle contractility and the lines of skin and fascial tension may also alter wound healing and the resultant scar appearance and strength. Therefore, important anatomic parameters to consider include the overlying skin, subcutaneous tissue depth, abdominal wall vessels, and abdominal wall muscles and their fascial sheaths and aponeuroses. Anterior wall anatomy is discussed and illustrated in Chapter 3 (p. 27).

Incisions that are most useful for obstetric patients include the midline (vertical) incision and the Pfannenstiel, Maylard, Cherney, and supraumbilical (transverse) incisions (Fig. 4-1). Of these, transverse incisions follow Langer lines of skin tension. Thus, excellent cosmesis can usually be achieved with the Pfannenstiel, Maylard, Cherney, and transverse supraumbilical incisions. According to a study by Rees and Coller (1943), the force required to approximate the edges of a vertical incision in the lower abdomen is 30 times greater than that required to reapproximate a transverse incision. Additionally, decreased rates of fascial wound dehiscence and incisional hernia are noted. Specifically, proponents suggest that transverse incisions are as much as 30 times stronger than midline incisions. Mowat and Bonnar (1971), for example, observed that abdominal wound dehiscence after cesarean delivery was eight times more frequent with a vertical incision than with a transverse incision. Older literature also reported that wound evisceration was three to five times more common, and hernias developed two to three times more often when vertical incisions were used (Helmkamp, 1977; Thompson, 1949; Tollefson, 1954). That said, some studies indicate that this increased incidence of eviscerations with vertical incisions was secondary to inappropriate closures. Indeed, more recent studies show an advantage of midline vertical incisions compared with transverse incisions to avoid dehiscence, or note no difference (Farnell, 1986; Greenburg, 1979). Dehiscence and herniation aside, cosmesis is clearly better with transverse incisions.

Transverse Incisions

These incisions not only produce good cosmetic results but are also less painful. Additionally, when these incisions are placed in the lower abdomen, they interfere less with postoperative respiratory movement, thereby aiding easier recovery. Transverse incisions, however, do have certain disadvantages. Of primary importance, a transverse incision often offers less abdominal operating room than a low transverse incision. Others include: (1) the division of multiple layers of fascia and muscle can result in the formation of dead spaces; (2) there is comparatively more bleeding; (3) these incisions are relatively more time consuming; and (4) transverse incisions may result in division of nerves, most notably the ilioinguinal and iliohypogastric nerves (Tollefson, 1954). These latter nerves pierce the fascial sheath of the internal oblique just medial to the anterior superior iliac spine and superior to the inguinal ligament. Coursing medially, they provide sensory innervation to the suprapubic area, mons pubis, and medial upper thigh (Fig. 4-2). Studies have demonstrated anatomic variation in the courses of these nerves (Rahn, 2010; Whiteside, 2003). This, combined with difficulty in visual identification, makes them vulnerable to disruption and entrapment even with a properly performed Pfannenstiel incision.

Pfannenstiel Incision

This is an excellent incision that offers adequate exposure for cesarean delivery and optimal cosmesis. As such, it is the preferred incision for nonobese women when the extra speed of delivery afforded by a vertical incision is not essential. With a Pfannenstiel incision, exposure of the pregnant uterus often is marginal, particularly in the obese woman. Also, the potential to lengthen the incision is limited. Moreover, extending the incision laterally is difficult, and the required dissection often leads to small-vessel injury. This may compromise hemostasis and necessitate a subfascial closed drainage system. Thus, the Pfannenstiel incision can be less than ideal if rapid entry, greater operating room, or upper abdominal access is critical. Examples include emergency cesarean delivery or reexploration of a patient with suspected hemorrhage or bowel injury.

To begin, the skin incision follows a semielliptical curve. Its lateral points are directed toward the anterior superior iliac spines. The midportion of the incision lies within the area of clipped pubic hair and approximately 1 to 2 cm above the symphysis pubis. Its length depends upon the amount of exposure required. The average incision begins and ends 2 or 3 cm below and medial to the anterior iliac crests. During skin incision, the scalpel blade is oriented perpendicular to the skin throughout. This avoids beveled skin edges, which degrade wound reapproximation and healing.

The adipose layer is also cut transversely. Bleeding can be minimized using an electrosurgical blade to coagulate vessels of this layer, with special attention to the superficial epigastric artery. As shown in Figure 4-2, this artery runs longitudinally and can be found approximately 3 cm from the midline in this incision. Alternatively, blunt dissection of the adipose tissue with a retractor, from medial to lateral, moves the superficial epigastric arteries away from the dissection, which can decrease bleeding.

The anterior fascial sheath of the rectus abdominis muscles is exposed. It is then incised transversely in the midline sufficiently to expose the anterior surface of these muscles (Fig. 4-3). On each side, this dissection is carried laterally, using scissors or an electrosurgical blade. Ideally, this lateral extension cuts each layer individually (Fig. 4-4). This permits identification and, ideally, avoidance of the iliohypogastric and ilioinguinal nerves as they run between these two fascial layers. Moreover, the fascia is elevated off the muscle to prevent muscle fiber transection or bleeding.

Next, the superior fascial edge is grasped with a Kocher clamp on either side of the midline. Traction is directed cephalad and slightly outward. Blunt dissection beneath the anterior fascia is then used to separate the fascia off the underlying rectus abdominis muscles (Fig. 4-5). The dissection begins just lateral to the linea alba and is carried laterally. During this separation of the anterior fascial sheath off the rectus abdominis muscle bellies, methodical dissection ideally isolates small perforating vessels. These can be coagulated and then transected. The fascia separates easily from the bellies of the rectus muscle, but it may be densely adhered along the midline and require sharp dissection with curved Mayo scissors (Fig. 4-6). Upon completion of this dissection, a semicircular area with a radius of 6 to 8 cm has been created. The area inferior to the initial fascial incision is then similarly separated.

Thereafter, the rectus abdominis muscles are bluntly parted from each other longitudinally in the midline. The pyramidalis muscle, located superficial to the rectus abdominis muscle, usually requires sharp division in the midline.

After separation of the rectus muscle bellies, the thin, filmy peritoneum is identified, grasped with two hemostats, elevated away from potential bowel and omentum, and sharply incised. Incision of the underlying peritoneum is made in a vertical fashion and extended cephalad to the extent that the rectus abdominis muscles are divided and extended caudad to the dome of the bladder (Fig. 4-7). Cystotomy is always a concern. Decompressing the bladder with an indwelling catheter and performing the inferior portion of this dissection in layers helps to prevent bladder laceration (Fig. 4-8). Following peritoneal entry, the planned operation is completed. For fascial closure, a running suture line is usually selected for a clean or clean-contaminated wound (Fig. 4-9). A complete discussion of closure technique is found on page 60.

Cherney Incision

In some cases a low transverse abdominal incision will not be large enough to deliver the infant safely or to obtain adequate exposure for hemostasis. The practice of “half transecting” the rectus abdominis muscles in this situation is discouraged for reasons explained later. Thus, under the noted circumstances, a Cherney incision may be preferred (Cherney, 1941). This incision divides the caudal tendons of both rectus abdominis muscle bellies to provide additional operating space. The Cherney incision is approximately 25-percent longer than a midline vertical incision made from the umbilicus to the symphysis pubis. It also exposes the pelvic sidewall when needed, for example, for internal iliac artery ligation.

During tendon transection, the bladder is at risk for injury. Preventively, a surgeon can insert one finger between the tendon and bladder and into the space of Retzius, which is the retropubic space. If the peritoneum is already incised, the space of Retzius can be developed by blunt dissection. Downward traction and pressure in the relatively bloodless midline beneath the rectus abdominis muscle can easily open the space of Retzius. At this level on the anterior abdominal wall, the inferior epigastric vessels are located laterally so injury can be avoided and their ligation is not required. The surgeon’s finger is inserted into the space of Retzius and deep to the tendons (Fig. 4-10). The pyramidalis muscles and the tendinous distal rectus abdominis muscle are then sharply divided near their insertion into the pubis. Bleeding is negligible in this portion of the muscle.

The muscles are then reflected cephalad to reveal the peritoneum. The peritoneal incision can be extended laterally at a level approximately 2 cm cephalad to the bladder (Fig. 4-11).

For abdominal closure, the peritoneum is approximated separately with a fine-gauge chromic or polyglycolic acid suture in a running fashion. The need for drainage of the subfascial space is assessed individually, but in general, drains are avoided. The ends of the rectus tendons are reapproximated to the inferior portion of the rectus sheath with six to eight interrupted or horizontal mattress stitches using permanent suture (Fig. 4-12). The rectus tendons are not sutured directly to the symphysis pubis to avoid osteomyelitis. A running fascial closure can then be accomplished with no. 1 or no. 2 delayed-absorbable suture, as in the Pfannenstiel incision. Also, closure of the subcutaneous layer and skin is similar to that for the Pfannenstiel incision.

Maylard Incision

The true transverse muscle-cutting incision, the Maylard or Maylard-Bardenheuer incision, is a poor choice for cesarean delivery because of the greater operating time required. However, this incision affords excellent pelvic exposure and is used for radical pelvic surgery, including exenterations and removal of large adnexal masses (Maylard, 1907). For the obstetric patient, this incision can be used for exploratory laparotomy for postpartum bleeding, internal iliac artery ligation, or hysterectomy. It is an excellent choice for the woman treated by radical hysterectomy for cervical cancer in early pregnancy. Although it may be used for pregnant women with adnexal masses, exposure of the upper abdomen for possible surgical cancer staging is limited.

Importantly, some feel that a Pfannenstiel incision can be converted into a Maylard incision simply by incising the rectus abdominis muscles and avoiding the inferior epigastric vessels. As noted in the last section, this approach should not be pursued, as the dissection for a Pfannenstiel incision includes separation of the anterior fascial sheath from the underlying rectus abdominis muscle. The true Maylard incision does not include this dissection. Consequently, final reapproximation of the fascial incision with a Maylard incision also brings the divided rectus muscle bellies in apposition. However, if the rectus muscles are transected after Pfannenstiel dissection, this muscle fiber apposition is compromised.

The Maylard incision begins with a transverse skin incision made 3 to 8 cm above the symphysis pubis. Distance from the symphysis is selected depending on the woman’s size and indications for surgery. As shown in Figure 4-2, anterior abdominal wall anatomy varies depending on this distance from the symphysis. Thus, with lower incisions, the pyramidalis muscles are noted, and the inferior epigastric arteries lie lateral to the rectus bellies. With more cephalad incisions, the pyramidalis muscle are not seen and inferior epigastric vessels course more medially and behind the rectus abdominis bellies. In either instance, this transverse incision lies below the arcuate line. As such, the aponeurosis of the external and internal oblique muscles coalesces only on the anterior surface of the rectus abdominis muscle.

After incising the skin and subcutaneous layer, a transverse fascial incision is made in the midline and carried well lateral to the borders of the rectus muscles. Next, blunt dissection separates the overlying rectus muscle bellies from their underlying peritoneum. The muscles are divided using the scalpel or electrosurgical blade (Fig. 4-13). During or prior to this incision, the inferior epigastric vessels are identified lying on the posterior midportion of each muscle. The vessels are ligated with suture prior to further incision of the rectus muscles. This helps avoid vessel tearing, vessel retraction, and hematoma formation. In contrast, some surgeons advocate preserving these vessels, even when the rectus muscles are transected (Parson, 1968).