Choice of Abdominal Incision and Risk of Trauma to the Urinary Bladder and Bowel in Multiple Cesarean Sections

Abstract

The Pfannenstiel incision is commonly used in women having a first cesarean section (CS) and is also generally viewed as being safe for a second CS. Some clinicians believe, however, that a vertical midline subumbilical (MLSU) incision is less hazardous after multiple CS deliveries. This study compared the risk of bladder and bowel injuries associated with these incisions in a retrospective series of 3164 women having a repeat CS at a referral maternity hospital over a 4-year period in 1999–2003. Exclusion criteria included previous uterine rupture, previous dehiscence or rupture of a uterine scar, previous classic incision, need for a cesarean hysterectomy, or absence of any needed clinical data. Participants averaged 2.6 (range, 1–8) cesarean deliveries. The Pfannenstiel incision was used in 86% of cases and the MLSU incision in 14%. Surgeons appeared to have increasingly favored the latter approach as the number of previous sections increased. Bladder injuries totaled 19 and were significantly more frequent with the midline incision (odds ratio, 6.7; 95% confidence interval, 1.6–16.5). Factors associated with bladder injury were determined by multiple regression analysis, and only the presence of adhesions and anterior placenta previa were significantly associated with bladder trauma. Injuries did not always correlate with the surgeon’s level of experience, and no surgeon caused more than one injury. It also made no difference whether CS was done electively or on an emergency basis. Neither maternal body weight nor fetal birth weight influenced the risk of bladder injury. The incidence of bladder injury increased with the number of cesareans for both kinds of incisions, but increased more with the MLSU incision. Bladder injury was more frequent with the MLSU incision even after controlling for possibly confounding factors by multivariate analysis. Bowel injuries were also more numerous with the midline incision (relative risk, 5.5), but this trend did not reach statistical significance. All injuries at both sites were recognized and treated during CS. The Pfannenstiel abdominal incision caused fewer bladder and bowel injuries than the MLSU technique in women in this study who had multiple CS deliveries. The investigators recommend using the former approach unless a midline incision is clearly indicated.