Postoperative adhesions: an underappreciated complication of cesarean deliveries

Abstract

Cesarean deliveries now account for approximately one-third of all deliveries and represent the most common surgical procedure performed in the United States. Thus, there is a significant need to review the future maternal complications following cesarean deliveries (and multiple prior cesarean deliveries), the impact on the fetus, as well as long-term maternal outcomes. These issues are presented in the articles by Dr Lyell on perioperative complications of cesarean delivery and Drs Clark and Silver on long-term maternal outcomes. An underappreciated concern following cesarean delivery is development of postoperative adhesions. Several reports have identified the incidence of adhesions following cesarean delivery as 40-65%, with increasing occurrence following repeat cesarean deliveries. Interestingly, while the incidence is higher than many obstetricians may have anticipated, it is nonetheless, less than rates identified after another uterine procedure, myomectomy, in which rates are approximately 85% of patients. This raises the question of what accounts for this difference in the incidence of adhesions following surgery on the pregnant vs nonpregnant uterus. Possible explanations for the difference may range from aspects of the surgical procedure itself, to anatomical and physiologic factors, to molecular biologic differences induced by pregnancy. Regarding the former, cesarean deliveries are generally of shorter duration than myomectomies, with possible differences in myometrial (number of layers) and peritoneal closure, suture used, the number of uterine incisions, and the use of electrosurgery, as well as use of retractors and packing. Cesarean incisions are generally on the lower anterior surface and do not involve the posterior uterine surface (with its proximity to the adnexal structures), which is at increased risk for postsurgical adhesions. Additionally, uterine involution and/or the filling and emptying of the bladder may result in disruption of the fibrinous bands (the forerunner of adhesions that may form after cesarean delivery) connecting the anterior uterine and parietal peritoneal surfaces, thereby diminishing adhesion development. Finally, pregnancy per se, whether due to hormonally induced changes or other factors, may influence peritoneal repair. For example, plasminogen activator activity, which is responsible for degradation of the fibrinous mass, is enhanced during pregnancy and may thereby, reduce development of adhesions by elimination of the fibrinous mass prior to fibroblast infiltration, with deposition of collagen and other forms of extracellular matrix. Delineation of the reason(s) for differences in adhesions in the pregnant and nonpregnant uterus will also be of significance for women undergoing repeat cesarean delivery. Just as in nonpregnant women, in whom adhesion reformation is more common than de novo adhesion formation, the likelihood of uterine adhesions increases with multiple cesarean deliveries. Associated with repeat cesarean delivery are reports of enhancement of adverse maternal and fetal outcomes, including longer times to delivery, longer total surgical times, lower Apgar score at 1 minute, and increased incidence of maternal bladder injury, hemorrhage, and need for blood transfusions. Further evaluation is needed to determine whether these deleterious outcomes are due to adhesions per se or other factors, such as coexisting fibrosis in the anterior abdominal wall and/or the lower uterine segment. Inherent in such evaluations is also the question of the explanation for the interindividual variation in adhesions/fibrosis between individuals, as well as the question of why, within an individual, adhesions develop at one location but not adjacent locations. While answers to these critical questions are awaited, the final article by Drs Bates and Shomento provides approaches for current consideration of adhesion reduction following surgical procedures including cesarean delivery. I wish to thank Adam Perahia, MD; Joseph Melton, PhD; and InterQuest Medical & Scientific Communications for their editorial assistance in the preparation of these manuscripts within the supplement.