Anesthesia for myelomeningocele surgery in fetus

Comparison of terbutaline and atosiban as tocolytic agents in intrauterine repair of myelomeningocele: a retrospective cohort study

BACKGROUND

Myelomeningocele (MMC) is a neural tube defect disease. Antenatal repair of fetal MMC is an alternative to postnatal repair. Many agents can be used as tocolytics during the in utero fetal repair such as β2-agonists and oxytocin receptor antagonists, with possible maternal and fetal repercussions. This study aims to compare maternal arterial blood gas analysis between terbutaline or atosiban, as tocolytic agents, during intrauterine MMC repair.

METHODS

Retrospective cohort study. Patients were divided into two groups depending on the main tocolytic agent used during intrauterine MMC repair: atosiban (16) or terbutaline (9). Maternal arterial blood gas samples were analyzed on three moments: post induction (baseline, before the start of tocolysis), before extubation, and two hours after the end of the surgery.

RESULTS

Twenty-five patients were included and assessed. Before extubation, the terbutaline group showed lower arterial pH (7.347 ± 0.05 vs. 7.396 ± 0.02 for atosiban, p = 0.006) and higher arterial lactate (28.33 ± 12.76 mg.dL-1 vs. 13.06 ± 6.35 mg.dL-1, for atosiban, p = 0.001) levels.

CONCLUSIONS

Patients who received terbutaline had more acidosis and higher levels of lactate, compared to those who received atosiban, during intrauterine fetal MMC repair.

Manejo anestésico en histerotomía más corrección intrauterina de espina bífida abierta o mielomeningocele

La correcta puesta en marcha de la anestesia pediátrica y obstétrica es determinante para óptimos desenlaces en el manejo quirúrgico de las mujeres que durante su embarazo han presentado diagnóstico de mielomeningocele fetal (MMC). El objeto de realizar la resolución de ésta entidad antes del nacimiento se basa en menor requerimiento de derivaciones ventrículo peritoneal y mejoría en la función motora de los miembros inferiores. Dentro de las variables que representa este reto quirúrgico se encuentra la morbilidad materna, dehiscencia de histerorrafia, ruptura uterina secundaria a histerotomía y los consiguientes partos al actual por cesárea. La presente es una revisión no sistemática de la literatura acerca del manejo anestésico para el binomio madre-producto con MMC y con ello socializar al servicio de anestesiología la mejor estrategia en el manejo perioperatorio de estos pacientes.

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

OBJECTIVE

To describe changes in fetal Doppler parameters during a novel technique for open fetal microneurosurgery for open spina bifida (OSB) repair.

METHODS

This was a prospective study of 44 fetuses undergoing open fetal surgery for OSB repair using a novel microneurosurgery approach that is characterized by a mini-hysterotomy (diameter of 15 mm), minimal fetal manipulation and maintenance of a constant normal amniotic fluid volume throughout the procedure. Doppler velocimetry of the umbilical artery (UA), fetal middle cerebral artery (MCA) and ductus venosus (DV) was performed before the start of surgery and at prespecified timepoints during fetal surgery. UA pulsatility index (PI) > 95^th percentile, DV-PI > 95^th percentile, MCA-PI < 5^th percentile and cerebroplacental ratio (CPR) < 5^th percentile were considered abnormal.

RESULTS

Median gestational age at fetal surgery was 25.2 weeks (range, 22.9-27.9 weeks). Doppler recordings were successfully obtained in all cases during all timepoints throughout the surgery. As compared with Doppler values before surgery, there was a significant increase in the proportion of fetuses with MCA-PI < 5^th percentile (63.6% vs 13.6%; P < 0.001), CPR < 5^th percentile (65.9% vs 15.9%; P < 0.001) and DV-PI > 95^th percentile (22.7% vs 0%; P = 0.01) and a non-significant increase in the proportion of fetuses with UA-PI > 95^th percentile (11.4% vs 0%; P = 0.12) during fetal surgery. None of the fetuses showed absent or reversed end-diastolic velocity in the UA or absent or reversed DV a-wave at any stage during OSB repair. All abnormal Doppler parameters returned to normal after surgery.

CONCLUSIONS

During open fetal surgery for OSB repair, a small hysterotomy, reduced fetal manipulation and maintenance of a normal amniotic fluid volume seem to prevent severe fetal Doppler abnormalities. The mild Doppler changes observed during fetal surgery could be a manifestation of fetal adaptation to the stress of fetal surgery. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Open intrauterine repair of spina bifida aperta: Historical aspects, current availability, and clinical outcomes from the Latin American Spina Bifida Consortium

OBJECTIVE

To determine the historical aspects, current availability, and clinical outcomes of open intrauterine repair of spina bifida aperta (IRSBA) in Spanish-speaking Latin American countries.

METHODS

Cases were collected from centers with at least 2 years of experience and a minimum of 10 open IRSBA interventions by December 2020. Clinical variables were compared to the results of the Management of Myelomeningocele Study (MOMS) trial.

RESULTS

Clinical experience with 314 cases from seven centers was reviewed. Most cases (n = 189, 60.2%) were performed between 24 and 25.9 weeks' gestation. Delivery at less than 30 weeks' gestation occurred in 36 cases (11.5%) and the overall perinatal mortality rate was 5.4% (17 of 314). The rate of maternal complications was low, including the need for blood transfusion (n = 3, 0.9%) and dehiscence or a thin uterine scar (n = 4, 1.3%). No cases of maternal death were recorded. Fifteen neonates required additional surgical repair of the spinal defect (4.8%) and 63 of 167 infants (37.7%) required a cerebrospinal fluid diversion procedure. Only two of the seven centers reported preliminary experience with fetoscopic IRSBA.

CONCLUSIONS

Clinical experience and outcomes were within the expected results reported by the MOMS trial. There is still very limited experience with fetoscopic IRSBA in this part of the world.

Effects of general anaesthesia during pregnancy on neurocognitive development of the fetus: a systematic review and meta-analysis

BACKGROUND

The US Food and Drug Administration warned that exposure of pregnant women to general anaesthetics may impair fetal brain development. This review systematically evaluates the evidence underlying this warning.

METHODS

PubMed, EMBASE, and Web of Science were searched from inception until April 3, 2020. Preclinical and clinical studies were eligible. Exclusion criteria included case reports, in vitro models, chronic exposures, and exposure only during delivery. Meta-analyses were performed on standardised mean differences. The primary outcome was overall effect on learning/memory. Secondary outcomes included markers of neuronal injury (apoptosis, synapse formation, neurone density, and proliferation) and subgroup analyses.

RESULTS

There were 65 preclinical studies included, whereas no clinical studies could be identified. Anaesthesia during pregnancy impaired learning and memory (standardised mean difference -1.16, 95% confidence interval -1.46 to -0.85) and resulted in neuronal injury in all experimental models, irrespective of the anaesthetic drugs and timing in pregnancy. Risk of bias was high in most studies. Rodents were the most frequently used animal species, although their brain development differs significantly from that in humans. In a minority of studies, anaesthesia was combined with surgery. Monitoring and strict control of physiological homeostasis were below preclinical and clinical standards in many studies. The duration and frequency of exposure and anaesthetic doses were often much higher than in clinical routine.

CONCLUSION

Anaesthesia-induced neurotoxicity during pregnancy is a consistent finding in preclinical studies, but translation of these results to the clinical situation is limited by several factors. Clinical observational studies are needed.

PROSPERO REGISTRATION NUMBER

CRD42018115194.

Low Transverse versus Midline Abdominal Skin Incisions for in utero Spina Bifida Repair

OBJECTIVE

The 2 types of maternal skin incisions for in utero spina bifida repair are low transverse (LT) incision perceived to be cosmetic benefit and midline longitudinal (ML) incision, typically associated with a reduction in surgical time and lower blood loss. Our objective was to compare short- and long-term outcomes associated with these 2 types of skin incisions following in utero spina bifida repair.

METHODS

Prospective observational cohort of 72 patients undergoing fetal spina bifida repair at a single institution between September 2011 and August 2018. The decision for the type of incision was at the discretion of the surgeons. The primary outcome was total operative time. Secondary outcomes included an analog scale of wound pain score on postoperative day 3, duration of postoperative stay, and postoperative wound complications within the first 4 weeks. The Patient Scar Assessment Questionnaire, a validated questionnaire, was obtained for all patients (≥6 months from delivery) using 4 categories (appearance, consciousness, satisfaction with appearance and with symptoms), with higher scores reflecting a poorer perception of the scar.

RESULTS

There were 43 women (59.7%) in the LT group and 29 (40.3%) in the ML group. In all patients, the same incision was used during cesarean delivery. The total operative time was higher in the LT group by 33 min (p < 0.001), primarily due to abdominal wall incision time (open and closure). No significant differences were found between the groups in pain score, length of postoperative stay, or the rate of wound complications. Fifty-three patients (73.6%) responded to the questionnaire, 36/43 from the LT group and 17/29 from the ML group. There was no difference in the scores of appearance, consciousness, and satisfaction with appearance and symptoms between the groups.

CONCLUSION

ML incisions shorten operative times without altering long-term incision-related satisfaction when compared to LT incisions.

Open Fetal Microneurosurgery for Intrauterine Spina Bifida Repair

OBJECTIVES

The aim of the study was to describe the feasibility of open fetal microneurosurgery for intrauterine spina bifida (SB) repair and to compare perinatal outcomes with cases managed using the classic open fetal surgery technique.

METHODS

In this study, we selected a cohort of consecutive fetuses with isolated open SB referred to our fetal surgery center in Queretaro, Mexico, during a 3.5-year period (2016-2020). SB repair was performed by either classic open surgery (6- to 8-cm hysterotomy with leakage of amniotic fluid, which was replaced before uterine closure) or open microneurosurgery, which is a novel technique characterized by a 15- to 20-mm hysterotomy diameter, reduced fetal manipulation by fixing the fetal back, and maintenance of normal amniotic fluid and uterine volume during the whole surgery. Perinatal outcomes of cases operated with the classic open fetal surgery technique and open microneurosurgery were compared.

RESULTS

Intrauterine SB repair with a complete 3-layer correction was successfully performed in 60 cases either by classic open fetal surgery (n = 13) or open microneurosurgery (n = 47). No significant differences were observed in gestational age (GA) at fetal intervention (25.4 vs. 25.1 weeks, p = 0.38) or surgical times (107 vs. 120 min, p = 0.15) between both groups. The group with open microneurosurgery showed a significantly lower rate of oligohydramnios (0 vs. 15.4%, p = 0.01), preterm rupture of the membranes (19.0 vs. 53.8%, p = 0.01), higher GA at birth (35.1 vs. 32.7 weeks, p = 0.03), lower rate of preterm delivery <34 weeks (21.4 vs. 61.5%, p = 0.01), and lower rate of perinatal death (4.8 vs. 23.1%, p = 0.04) than the group with classic open surgery. During infant follow-up, the rate of hydrocephalus requiring ventriculoperitoneal shunting was similar between both groups (7.5 vs. 20%, p = 0.24). All patients showed an intact hysterotomy site at delivery.

CONCLUSION

Intrauterine spina repair by open fetal microneurosurgery is feasible and was associated with better perinatal outcomes than classic open fetal surgery.

Prenatal Repair of Spina Bifida: A 2-Center Experience with Open Intrauterine Neurosurgery in Chile

OBJECTIVE

To report the experience with prenatal repair of open spina bifida (OSB) from 2 centers in Chile.

METHODS

Women with a second-trimester fetus with OSB were offered intrauterine neurosurgical repair following the protocol from the Management of Myelomeningocele Study (MOMS) trial. Pediatric follow-up with infants reaching 12 and 30 months of life was also reviewed.

RESULTS

Fifty-eight fetuses with OSB underwent intrauterine repair at an average (±SD) gestational age of 24.8 ± 0.9 weeks. There were 3 (5.1%) intrauterine deaths. The average gestational age at delivery of the remaining 55 cases was 33.3 ± 3.6 weeks, and the average birth weight was 2,172 ± 751 g. Delivery before 30 weeks occurred in 11 cases (20.0%). Two (3.6%) neonatal deaths (<28 days) occurred. At 12 months, a ventriculoperitoneal shunt or an endoscopic third ventriculostomy was required in 25% of the cases. At 30 months, 72.4% of the infants were able to walk.

DISCUSSION

Prenatal neurosurgical repair of OSB is a complex and challenging intervention. Major complications include perinatal death and severe prematurity. No major maternal complications occurred in our series. A reduction in the need for cerebrospinal fluid diversion and an improved ability to walk seem to be the greatest long-term advantages of this procedure.

Peri-operative management of percutaneous fetoscopic spina-bifida repair: a descriptive review of five cases from the United Kingdom, with focus on anaesthetic implications

We present a case-based review of the first five percutaneous fetoscopic in-utero spina bifida repair procedures undertaken in the UK. Our focus is on implications of anaesthesia and analgesia for the mother and fetus, provision of uterine relaxation and fetal immobilisation while providing conditions conducive to surgical access. Minimising risks for fetal acidosis, placental and fetal hypoperfusion, maternal and fetal sepsis and maternal fluid overload were the foremost priorities. We discuss optimisation strategies undertaken to ensure fetal and maternal well-being under anaesthesia, shortcomings in the current approach, and possible directions for improvement.

Use of plastic wound retractor at hysterotomy site in prenatal repair of myelomeningocele: a new technique

Objective: To describe the use of a self-retaining thermoplastic polyurethane wound retractor for the management of hysterotomy during prenatal repair of myelomeningocele.Methods: The preliminary experience with 16 consecutive cases of open surgery for prenatal repair of myelomeningocele using a new technique is presented. Under general anesthesia, the gravid uterus was partially exteriorized through a low transverse abdominal incision and a high 3-4-cm midline vertical mini-hysterotomy was performed. After chorioamniotic membranes were opened with scissors, the internal ring of the retractor was placed into the amniotic cavity to compress the chorioamniotic membranes against the internal uterine wall and permit full retraction of the hysterotomy. Once the neurosurgical intervention was completed, the retractor was removed manually and uterine and abdominal incisions were closed using conventional techniques. Intra- and post-operative complications, as well as short-term pregnancy outcomes, were evaluated.Results: Intrauterine surgery was performed at a mean gestational age of 25.3 weeks and all except two of the interventions were completed within 3.0 h. When compared with the technique described in the Management of Myelomeningocele study (MOMS) trial, the use of the retractor was associated with a lower, although statistically nonsignificant, rate of chorioamniotic membrane separation (20/78 (26%) versus 2/16 (13%), respectively), preterm rupture of membranes (36/78 (46%) versus 4/16 (25%), respectively), and persistent oligohydramnios (16/78 (21%) versus 1/16 (6%), respectively) as well as higher gestational age at delivery (34.1 weeks ± 3.1 versus 36.0 weeks ± 1.93, respectively) and birthweight (2383 g ± 688 versus 2790 g ± 529, respectively). There were no intra- or post-operative complications associated with the use of the device. Only one (6%) of the hysterotomy scars was noted to be thin at the time of the cesarean delivery and no cases of dehiscence occurred.Conclusions: The use of a plastic wound retractor at the hysterotomy site provides a less traumatic approach than the conventional technique for the management of the uterine incision during open intrauterine surgery. Our experience with this technique was associated with short-term pregnancy outcomes that are similar and perhaps even superior to the technique reported in the MOMS trial. Because the device is inexpensive, easy to use, and widely available, its use during open intrauterine surgery should be considered. However, further clinical experience is required to reach a definitive conclusion regarding whether this technique should be incorporated into the protocol of prenatal repair of myelomeningocele.