Doppler changes in umbilical artery, middle cerebral artery, cerebroplacental ratio and ductus venosus during open fetal microneurosurgery for intrauterine open spina bifida repair

Fetal cardiovascular changes during open and fetoscopic in-utero spina bifida closure

OBJECTIVE

Fetoscopic closure of spina bifida using heated and humidified carbon dioxide gas (hhCO2) has been associated with lower maternal morbidity compared with open closure. Fetal cardiovascular changes during these surgical interventions are poorly defined. Our objective was to compare fetal bradycardia (defined as fetal heart rate (FHR) < 110 bpm for 10 min) and changes in umbilical artery (UA) Doppler parameters during open vs fetoscopic closure.

METHODS

This was a prospective cohort study of 22 open and 46 fetoscopic consecutive in-utero closures conducted between 2019 and 2023. Both cohorts had similar preoperative counseling and clinical management. FHR and UA Doppler velocimetry were obtained systematically during preoperative assessment, every 5 min during the intraoperative period, and during the postoperative assessment. FHR, UA pulsatility index (PI) and UA end-diastolic flow (EDF) were segmented into hourly periods during surgery, and the lowest values were averaged for analysis. Umbilical vein maximum velocity was measured in the fetoscopic cohort. At each timepoint at which FHR was recorded, maternal heart rate and systolic and diastolic blood pressure were measured.

RESULTS

Fetal bradycardia occurred in 4/22 (18.2%) cases of open closure and 21/46 (45.7%) cases of fetoscopic closure (P = 0.03). FHR decreased gradually in both cohorts after administration of general anesthesia and decreased further during surgery. FHR was significantly lower during hour 2 of surgery in the fetoscopic-repair cohort compared with the open-repair cohort. The change in FHR from baseline in the final stage of fetal surgery was significantly more pronounced in the fetoscopic-repair cohort compared with the open-repair cohort (mean, -32.4 (95% CI, -35.7 to -29.1) bpm vs -23.5 (95% CI, -28.1 to -18.8) bpm; P = 0.002). Abnormal UA-EDF (defined as absent or reversed EDF) occurred in 3/22 (13.6%) cases in the open-repair cohort and 23/46 (50.0%) cases in the fetoscopic-repair cohort (P = 0.004). There were no differences in UA-EDF or UA-PI between closure techniques at the individual stages of assessment.

CONCLUSIONS

We observed a decrease in FHR and abnormalities in UA Doppler parameters during both open and fetoscopic spina bifida closure. Fetal bradycardia was more prominent during fetoscopic closure following hhCO2 insufflation, but FHR recovered after cessation of hhCO2. Changes in FHR and UA Doppler parameters during in-utero spina bifida closure were transient, no cases required emergency delivery and no fetoscopic closure was converted to open closure. These observations should inform algorithms for the perioperative management of fetal bradycardia associated with in-utero spina bifida closure. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Effect of Combining Intrauterine Cerebral Blood Flow Changes with Electrical Activity on Prognostic Evaluation of Brain Injury

OBJECTIVES

We sought to investigate the value of combining intrauterine cerebral blood flow changes with brain electrical activity examination in evaluating the prognosis of brain injury.

METHODS

A total of 90 preterm infants were enrolled and divided into 2 groups: the brain damaged preterm infants group (n = 55) and the nonbrain damaged preterm infants group (n = 35). The diagnostic efficacy of combining intrauterine cerebral blood flow changes with electroencephalogram (EEG) activity examination in predicting the prognosis of preterm infants with brain injury was evaluated using T-test. Pearson linear correlation was applied to analyze the relationship between fetal intrauterine cerebral blood flow changes combined with electrical activity examination and the prognosis of brain injury.

RESULTS

Significant differences were seen in pulse index, the ratio of peak systolic velocity to end diastolic velocity ratio, and other indexes between the 2 groups (P < 0.05). The combined approach of intrauterine cerebral blood flow changes with EEG activity examination demonstrated significantly higher values for area under the curve, sensitivity and negative predictive value compared to using intrauterine cerebral blood flow changes or EEG activity examination alone (P < 0.05). A positive correlation was found between fetal intrauterine cerebral blood flow and electrical activity examination (P < 0.05).

CONCLUSIONS

Combining the assessment of intrauterine cerebral blood flow changes with cerebral electrical activity examination proved beneficial in diagnosing the prognosis of brain injury and provided an important reference for early clinical intervention.

Middle Cerebral Artery Doppler before and after Fetal Spina Bifida Repair: An Indirect Sign of Hindbrain Compression and Decompression?

INTRODUCTION

Reduced middle cerebral artery resistance indices (MCA-RI) in fetuses with spina bifida (fSB) are commonly observed. Compression of neuronal pathways in the brainstem due to hindbrain herniation (HH) and disturbed cerebrospinal fluid circulation likely cause an imbalance of the autonomic nervous system. This may increase systemic vasoconstriction and compensatory increase cerebral vasodilation (like brain sparing). The aim of this study was to systematically analyze all fetal MCA-RI before and after fSB repair and to compare their correlation with the presence and postsurgical resolution of HH.

METHODS

173 patients were included. Standardized ultrasound examinations including MCA and umbilical artery (UA) Doppler as well as assessment of HH presence and regression were performed. Fetuses with MCA-RI <5th percentile (P) before fetal surgery were compared to the group with normal MCA-RI and correlated to the presence of HH before and its regression after fSB repair.

RESULTS

30% (49/161) fetuses showed RI's <5th P before fSB repair. All fetuses had normal UA-RI. 99.4% of fetuses (160/161) showed normal of MCA-RI before delivery. Normalization occurred within a mean of 1.3 ± 1.2 weeks. HH regression was observed in 97% in the group with normal MCA-RI and in 96% in the group with MCA-RI <5th P before surgery (p = 0.59). Time lapse to HH regression after fSB repair was 1.8 ± 1.7 and 1.9 ± 1.6 weeks, respectively.

CONCLUSION

In fetuses with MCA-RIs <5 P before fSB repair, a parallel timely course of MCA-RI normalization and HH regression was noted. To suggest common pathogenic factor(s), more studies are needed. However, normalization of the fetal cerebral circulation could be a further benefit of fSB repair.

Double Myelomeningocele Repair by Fetal Surgery with a Single Micro-Hysterotomy

INTRODUCTION

Open spina bifida (OSB) is the most common congenital anomaly of the central nervous system. It is associated with severe neurodevelopmental delay, motor impairment, hydrocephalus, and bowel and bladder dysfunction. In selected cases, intrauterine spina bifida repair has been shown to improve neonatal outcomes. Rarely, the spine can have a double defect compromising two different segments and there is a lack of evidence on the feasibility and benefits of intrauterine repair in these cases.

CASE PRESENTATION

We present a case with both cervicothoracic and lumbosacral myelomeningocele, Arnold-Chiari malformation type II and bilateral ventriculomegaly, that was treated successfully at 25 weeks with open micro-neurosurgery. Double myelomeningocele was successfully treated through a single 2-cm micro-hysterotomy, by performing external versions to sequentially expose and repair both defects. Weekly postoperative follow-up showed no progression of ventriculomegaly or complications attributable to the procedure. Preterm rupture of membranes prompted a conventional cesarean delivery at 32 weeks of gestation. Neurodevelopmental outcome at 20 months was within normal ranges, having achieved ambulation without orthopedic support and with no need for ventriculoperitoneal shunting.

CONCLUSION

This report demonstrates for the first time the feasibility of double OSB repair through a single 2-cm micro-hysterotomy, suggesting that selected isolated cases of double myelomeningocele could be candidates for fetal intervention. Further prospective studies should be carried out to assess the potential benefit of double OSB intrauterine open repair.

Impact on postoperative, neonatal and 2-year neurodevelopmental outcomes of UA-AREDF during and after fetal spina bifida repair

OBJECTIVE

Absent or reversed end-diastolic flow (AREDF) in the umbilical artery (UA) on Doppler is a known phenomenon during fetal interventions, such as fetal open spina bifida (OSB) repair. We aimed to evaluate the clinical importance of these Doppler findings by investigating the impact of UA-AREDF on postoperative, neonatal and 2-year neurodevelopmental outcomes.

METHODS

This was a prospective study of pregnancies undergoing fetal OSB repair at the Zurich Center for Fetal Diagnosis and Therapy between 2010 and 2019. The group with UA-AREDF during or immediately after the intervention was compared to the group with normal UA Doppler. Primary endpoint was the FIGO scores of cardiotocography (CTG) 1, 2 and 6 h postoperatively and on day 1 after surgery. Secondary endpoints were the neonatal parameters and 2-year neurodevelopmental outcome assessed using the Bayley Scales of Infant and Toddler Development, Third Edition.

RESULTS

Data of 130 patients were analyzed. None of the fetuses had UA-AREDF before OSB repair. Normal UA Doppler was observed in 107 (82%) patients and UA-AREDF was observed in 23 (18%) during or immediately after OSB surgery. UA-AREDF was more often observed after version of the fetus (P = 0.045). Seventeen (13%) cases had absent end-diastolic flow (UA-AEDF) and six (5%) cases had reversed end-diastolic flow (UA-REDF). UA-AREDF disappeared in all 23 cases within the first day after OSB surgery. One-third of all CTGs were restricted in oscillation after surgery, but no significant difference in CTG 1, 2 and 6 h postoperatively or on the first postoperative day was found between the UA-AREDF and normal-Doppler groups (P > 0.05). Gestational age at delivery, UA pH, 5-min Apgar score and birth weight were comparable between the two groups, and there was no difference in the 2-year neurodevelopmental outcome (P > 0.05). The neonatal and 2-year neurodevelopmental outcomes also did not differ significantly between the UA-REDF and UA-AEDF groups.

CONCLUSIONS

Postoperative CTG abnormalities occur and recover at a similar rate in fetuses with transitory UA-AREDF and those with normal Doppler during fetal OSB repair. UA-AREDF during fetal OSB repair did not negatively influence postnatal or 2-year neurodevelopmental outcomes. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Anesthesia for fetal operative procedures: A systematic review

Objective

The anesthetic management of fetal operative procedures (FOP) is a highly debated topic. Literature on fetal pain perception and response to external stimuli is rapidly expanding. Nonetheless, there is no consensus on the fetal consciousness nor on the instruments to measure pain levels. As a result, no guidelines or clinical recommendations on anesthesia modality during FOP are available. This systematic literature review aimed to collect the available knowledge on the most common fetal interventions, and summarize the reported outcomes for each anesthetic approach. Additional aim was to provide an overall evaluation of the most commonly used anesthetic agents.

Methods

Two systematic literature searches were performed in Embase, Medline, Web of Science Core Collection and Cochrane Central Register of Controlled Trials up to December 2021. To best cover the available evidence, one literature search was mostly focused on fetal surgical procedures; while anesthesia during FOP was the main target for the second search. The following fetal procedures were included: fetal transfusion, laser ablation of placental anastomosis, twin-reversed arterial perfusion treatment, fetoscopic endoluminal tracheal occlusion, thoraco-amniotic shunt, vesico-amniotic shunt, myelomeningocele repair, resection of sacrococcygeal teratoma, ligation of amniotic bands, balloon valvuloplasty/septoplasty, ex-utero intrapartum treatment, and ovarian cyst resection/aspiration. Yielded articles were screened against the same inclusion criteria. Studies reporting anesthesia details and procedures’ outcomes were considered. Descriptive statistical analysis was performed and findings were reported in a narrative manner.

Results

The literature searches yielded 1,679 articles, with 429 being selected for full-text evaluation. A total of 168 articles were included. Overall, no significant differences were found among procedures performed under maternal anesthesia or maternal-fetal anesthesia. Procedures requiring invasive fetal manipulation resulted to be more effective when performed under maternal anesthesia only. Based on the available data, a wide range of anesthetic agents are currently deployed and no consistency has been found neither between centers nor procedures.

Conclusions

This systematic review shows great variance in the anesthetic management during FOP. Further studies, systematically reporting intraoperative fetal monitoring and fetal hormonal responses to external stimuli, are necessary to identify the best anesthetic approach. Additional investigations on pain pathways and fetal pain perception are advisable.

Open surgery for in utero repair of spina bifida: Microneurosurgery versus standard technique - A systematic review

BACKGROUND/OBJECTIVES

Prenatal myelomeningocele (MMC) repair has been shown to improve neurological outcomes. It has been suggested that decreases in the hysterotomy diameter during surgery can improve perinatal outcomes without altering neurologic outcomes. The objective of this study is to describe and compare the main maternal and fetal outcomes of fetuses undergoing open surgery for MMC repair, through the different modifications (standard-classical, mini-hysterotomy, and microneurosurgery).

DATA SOURCE

MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Ovid, SciELO, LILACS, PROSPERO.

RESULTS

From a total of 112 studies, seven case series were selected including 399 fetuses with open fetal surgery, five studies using the classical technique (n = 181), one with mini-hysterotomy (n = 176), and one with the microneurosurgery technique (n = 42). The mini-hysterotomy and microneurosurgery techniques presented a lower risk of preterm delivery (21.4% and 30%, respectively) compared to the classic technique (47.3%), premature rupture of membranes (78%, 62%, and 72.5 %, respectively), oligohydramnios (0% and 72.5%, respectively), dehiscence of hysterotomy, maintaining the same frequency of Chiari reversion (78%, 62%, and 72.5%, respectively), postnatal correction requirement (0%, 4.8%, and 5.8%, respectively), and lower frequency of requirement for a ventriculoperitoneal shunt placement (13.0%, 7.5%, and 29.1%, respectively).

CONCLUSION

The least invasive techniques (minihysterotomy-microneurosurgery) are possible and reproduceable, as they are associated with better maternal and perinatal outcomes.

Brain Doppler abnormalities in fetuses with open spina bifida

BACKGROUND

To describe the brain Doppler changes in fetuses with isolated open spina bifida (OSB).

STUDY DESIGN

Doppler ultrasound measurements including the umbilical artery (UA) pulsatility index (PI), middle cerebral artery (MCA) PI, and their combination into the cerebroplacental ratio (CPR) and umbilicocerebral ratio (UCR) were performed in a cohort of fetuses with OSB. Included patients were individually matched to a control group without structural anomalies and similar gestational ages. MCA-PI and/or CPR values below the 5th centile were considered abnormal and indicative of cerebral blood redistribution, while UCR and UA-PI above the 95th centile were considered abnormal.

RESULTS

During the study period, 266 fetuses were recruited, 133 normally grown fetuses with OSB and 133 matched controls. Doppler recordings were successfully obtained in all fetuses at a median gestational age of 30.9 weeks. All cases showed UA-PI within normal ranges, but fetuses with OSB showed significantly higher frequency of cerebral blood redistribution (15.0 vs. 3.0%, p < .01), MCA-PI <5th centile (10.5% vs. 3.0%, p = .01), decreased CPR (9.8% vs. 2.3%, p = .01) and increased UCR (17.2 % vs 7.5 %, p =.02). The rate of cerebral blood redistribution was significantly higher in the OSB group with ventriculomegaly in comparison to those with OSB and normal lateral ventricle diameter (18.6% vs. 3.2%, respectively; p <.05).

CONCLUSION

A proportion of fetuses with isolated open spina bifida showed cerebral blood redistribution.