Maternal Subcutaneous Seroma Following Open Maternal Fetal Surgery for Closure of Fetal Open Neural Tube Defects

Introduction: Maternal seroma has been noted following open maternal fetal surgery (OMFS) for fetal neural tube defect (fNTD) closure but the risk factors, timing of diagnosis, natural course and clinical significance have not been reported. Methods: Retrospective review of 340 patients who underwent OMFS for fNTD. Postoperative ultrasound images were reviewed and seroma details were recorded. Perioperative characteristics and delivery outcomes were then compared in patients that did or did not develop a seroma after OMFS. Multivariable logistic regression was performed to identify risk factors for seroma. Results: Of 330 patients with ongoing pregnancies at least 10 days after OMFS,122 patients (37%) had sonographic evidence of seroma on postoperative imaging. Median postoperative day at diagnosis was 11 with median time to resolution of 21 days. Median longest diameter at diagnosis was 5.23 cm with an initial volume of 9.66 mL. Seromas minimally increased in size prior to resolution. Multivariable logistic regression identified increasing maternal age and BMI as significant risk factors for seroma (OR 1.08 and 1.17). There was no difference in the incidence of post-OMFS complications in those who did and did not develop seroma, including no difference in the rate of membrane separation, oligohydramnios, preterm premature rupture of membranes, placental abruption, preterm labor, gestational age at delivery, fetal demise, or hysterotomy dehiscence. Following cesarean delivery, there was no difference in wound infection, but there was a higher incidence of wound separation in the group that had a seroma (7.4% vs 1.9%, p=0.019). Conclusion: In this cohort, one-third of patients undergoing OMFS developed seroma with no associated change in wound healing or prenatal course. Risk factors included older maternal age and increased BMI. Most were small and resolved, without intervention, prior to delivery. Following cesarean, there was an increased rate of wound separation in patients who previously developed seroma.