Incomplete Healing of the Uterine Incision After Caesarean Section: Is it Preventable?

Abstract

It is not unusual for a wedge-shaped distortion to compromise the integrity of a uterine incision scar resulting from cesarean section. Although it has been implicated in later uterine rupture, ectopic pregnancy, abnormal uterine bleeding, and dysmenorrhea, little is known about its cause or how to prevent it. This prospective, randomized trial compared 2 suturing techniques, full-thickness suturing that included the endometrial (decidual) layer of the uterine wall and split-thickness suturing that excluded the endometrial layer. Of the 78 nulliparous women in the study, 45 were in labor at the time of operative delivery and 33 had an elective cesarean. The Kerr technique was used for the uterine incision. Forty patients were assigned to full-thickness suturing and 38 to the split-thickness method. Transvaginal ultrasonography, with transverse and longitudinal sections, was scheduled 40 to 42 days postoperatively. A lack of complete apposition of the cranial and caudal edges of the incision, resulting in ballooning out toward the anterior abdominal wall, was considered evidence of incomplete healing. The final analysis included 38 women having full-thickness closure and 32 having the split-thickness procedure. The 2 groups were comparable in all respects. There were no immediate postoperative complications. Sonography demonstrated a wedge-type healing defect at the site of the uterine incision in 69% of the split-thickness and 45% of the full-thickness groups, a statistically significant difference (odds ratio, 2.72; 95% confidence interval, 1.02-7.27). Women whose scar healed incompletely had significantly less cervical dilation preoperatively as well as a thinner anterior and a thicker posterior uterine wall. On logistic regression analysis, significant factors in the state of healing 40 days postoperatively included the method used to suture the uterine incision, the degree of cervical dilation, and the thickness of the anterior and posterior uterine walls. In addition to the method used to suture the uterine scar at cesarean section, the degree of cervical dilation and possibly the contractile strength of uterine muscle influence the completeness of healing. When the cervix is closed, drainage of the uterine cavity may depend on vigorous uterine activity that leads to a thicker posterior uterine wall and thinning at the uterine incision site, particularly if the relatively strong endometrial layer is not included when repairing the uterine incision.