Since Victor Bonney first reported cesarean myomectomy in 1914, obstetricians have debated whether myomectomy should be performed simultaneously during CS until today. Obstetricians who oppose the indicated procedure believe the CM may carry a higher risk of complications, such as intraoperative and postpartum hemorrhage, prolonged operation time, even obstetric hysterectomy. However, leaving the fibroids untouched may affect uterine contraction, which leads to uterine atony and postpartum hemorrhage. In the long run, the still existing fibroids may bring about degeneration, menorrhagia, anemia, and compression on surrounding organs. Moreover, resection of fibroids is essential to improve the intrauterine microenvironment, increase the chance of conception, and improve subsequent pregnancy outcomes .
In a meta-analysis, Song et al. suggested that CM may not be appropriate for pregnant women with intramural fibroids. Roman et al. found that the incidence of hemorrhage in pregnant women with intramural fibroids was 21.2% when the fibroids were enucleated, compared with 12.8% for only cesarean section,but this increase did not reach statistical significance. Kim et al. reported the types of fibroids in patients who received CM with complications, and found that subserosal fibroids accounted for 10%, and the remaining 90% were intramural fibroids.
Contrary to the above point of views, our data revealed that intramural fibroids could be safely removed in CS. The incidence of intraoperative hemorrhage was 4.0% in the EM group and 8.3% in the SM group, blood transfusion rate was 2.0% and 8.3% in the above group, respectively. Furthermore, EM was associated with shorter operation and postoperative ventilation time than SM. It seems to provide another feasible solution to deal with intramural fibroids in CS correctly.
The EM technique should be particularly applicable to enucleate the intramural fibroids in CS due to uterine anatomical features and the consideration of taking full advantage of the incision made in the lower uterine segment. Studies have shown that as the uterus increases in size during pregnancy, the pseudocapsule of the fibroids becomes larger and more elastic, making it easier to remove completely. Our experience suggests that EM technique is more suitable for larger uterine fibroids. Because most of the uterine muscle wall is occupied by large fibroids, the remaining muscle layer becomes thinner, and it is easier to squeeze the fibroids into the uterine cavity, which facilitates the enucleation of the tumor nucleus through the endometrial incision during the operation. Thinner incision of the muscle layer is also conducive to less intraoperative bleeding. Conversely, it is difficult to expose smaller fibroids in the direction of the uterine cavity, and the transendometrial approach requires incision of the same or deeper myometrium compared with SM, so the advantage is not obvious.
In a multicenter study, Zhao et al. suggested that CM did not cause additional intraoperative bleeding and blood transfusion risks. The incidence of blood transfusion was only 0.7% in this study, which is much lower than our findings. It is worth noting that only 13.4% of fibroids in their study were larger than 5 cm in diameter, while the proportion of fibroids larger than 5 cm in the EM group and SM group in present study was 80% and 83.3%, respectively. Reviewing the literature, the incidence of major complications during CM is tightly correlated with the size of the fibroid, the cut-off point of fibroid size range from 5.0 cm to 8.0 cm in several studies, which could explain the significant differences in the incidence of blood transfusion.
In fact, this is not the first time our team has attempted to remove fibroids via lower uterine incision during CS. Previously, we successfully developed a surgical method to remove anterior uterine wall fibroids using the transverse incision in the lower uterine segment during CS. The principle of this procedure is squeezing the tumor in the direction of the lower uterine incision, then cut to the tumor wall at the most protruding part of the incisal margin, thus the tumor can be removed without additional incisions on the surface of the uterus. Previous studies have confirmed the efficacy of fibroids removal by transverse incision of lower uterine segment [23], the perioperative indicators such as intraoperative blood loss, blood transfusion rate and postoperative fever rate were not significantly different from those of the control group who underwent conventional trans-serosal method to remove the fibroids. However, the disadvantages of this procedure are obvious, as it cannot deal with fibroids in the posterior wall and those in the upper part of the uterine corpus and at the fundus, which are distant from the incision margin.
Uterine posterior wall fibroids with large size may makes it difficult to expose the uterus from the abdominal incision. Extensive and tight adhesions of the bowel to the posterior uterine wall caused by severe endometriosis also contribute to the above circumstance. In that situation, enucleation of posterior wall fibroids through uterine serosa becomes extremely difficult. Furthermore, it will prolong the operation time and increase the risk of massive bleeding during the operation. Resection of intramural myoma of the posterior wall via endometrial approach without large-scale adhesion separation is conducive to shortening the operation time and reducing the risk of bleeding. In addition, keeping the serosal surface intact prevents surgery interference on the intestine and reduces the incidence of postoperative ileus. This may explain why in present study, the time of operation and postoperative ventilation were shorter than that in the SM group.
Theoretically, intrauterine adhesions may occur in EM group because the incision is in the uterine cavity. However, no intrauterine adhesions were found by routine saline infusion sonography at six weeks postpartum in Hatinaz's study. Further research conducted by Huang et al. addressed this issue excellently. They longitudinally followed 63 patients who had undergone previous EM procedures, compared the surgical and obstetric outcomes of subsequent cesarean section with data of the first pregnancy. Results showed that the incidence of preterm birth and premature rupture of membranes decreased in subsequent pregnancies, while gestational age and neonatal birth weight increased significantly. There was no difference in the incidence of placenta previa, placental abruption, and uterine rupture. Thus cited authors concluded that EM procedure might improve the obstetric outcomes of subsequent pregnancy by getting rid of the influence caused by fibroids.
The main strength of this study is that it provided more evidence on how to manage the intramural fibroids in posterior wall of the uterus during CS properly. Despite much literature having investigated CM recently, there are few reports on intramural fibroids. Second, our data suggested that the dilemma of large fibroids in the posterior wall can be well resolved by EM procedure. The main limitation of this study is that it was a single-center retrospective analysis, In addition, data on long-term outcomes were not included in this study, especially effects on subsequent pregnancies such as the chance of conception, risk of uterine rupture, obstetric and surgical outcomes.