The rate of postoperative morbidity, including wound infections, is highly increased among patients who are obese. Transverse incisions may be more prone to infection when they are located in the moist folds of the panniculus. However, these incisions may provide more secure wound closure and reduce postoperative discomfort, resulting in earlier mobility and fewer respiratory complications. Vertical incisions provide improved surgical access and may be less prone to infection. Wall and colleagues studied the rate of postoperative wound complications with transverse and vertical incisions in obese women who were undergoing their first cesarean delivery.
The authors used hospital records to identify and assess women with a body mass index (BMI) of 35 or greater before pregnancy who were undergoing a primary cesarean delivery. Skin incisions were classified as transverse or vertical, and variables such as maternal age, gestational age at delivery, smoking history, indications for cesarean delivery, blood loss, operative time, and complications of pregnancy and delivery were recorded. The outcome of interest was any wound complication, further divided into infectious and noninfectious etiologies.
Data were available for 239 mothers, about two thirds of whom were white. The average age was 28 years. The women had high rates of preeclampsia, diabetes, and hypertension. The groups were comparable with regard to many characteristics, but those undergoing vertical incisions were significantly heavier (BMI 44.1 ± 6 compared with 41.2 ± 4.8) and significantly more likely to have wound complications despite greater use of subcutaneous sutures or drains.
The overall incidence of wound infection was 12.1 percent. Women with wound infections had longer hospital stays and an increased rate of endometritis. Wound complications were recorded in 20 of 213 (9.4 percent) transverse incisions and nine of 26 (34.6 percent) vertical incisions. Infectious wound complications were recorded in 7 percent of transverse incisions compared with 19 percent of vertical incisions; the rates of non-infectious complications were 2 and 15 percent, respectively. These differences were all highly significant statistically.
On statistical analysis, the only factors independently associated with wound complications were vertical skin incision and postpartum endometritis. A high preoperative hematocrit level was protective against wound complications. Other factors, including smoking status, use of subcutaneous drains or sutures, operative time, or use of regional anesthesia, were not independently associated with wound complications.
The authors conclude that primary cesarean delivery in severely obese patients is frequently complicated by wound infections. However, contrary to expectations, infections in vertical incisions appear to be associated with higher rates of wound complications than infections in transverse incisions.