Endoscopic coverage of fetal myelomeningocele in utero

Fetoscopic Myelomeningocele (MMC) Repair: Evolution of the Technique and a Call for Standardization

Fetal surgery has made significant strides over the past 40 years, facilitated by advances in technology and imaging modalities enabling the diagnosis and treatment of congenital anomalies in utero. The Management of Myelomeningocele Study (MOMS), a multicenter randomized controlled trial, established open fetal myelomeningocele (MMC) repair as the gold standard for improving neurological outcomes compared to postnatal repair. However, this approach is associated with increased maternal complications and preterm birth due to hysterotomy, prompting the exploration of minimally invasive alternatives. Due to the lack of an existing randomized control trial with fetoscopic MMC repair and variations in technique (percutaneous versus laparotomy/transuterine access, different trocar configurations, closure methods, and patch applications) among different fetal centers, more studies are needed to optimize this approach as an alternative to the standard of care. This paper proposes to assess the basics tenets of open fetal MMC repair and to establish guiding principles for a fetoscopic approach that could prove to be equivalent or superior to open fetal MMC repair in maternal and fetal outcomes and lead to clinical implementation.

Minimally Invasive Fetoscopic Resection of Life-Threatening Amniotic Band Constrictions in a Human Fetus at 22 + 2 Weeks of Gestation Complicated by Subtotal Chorioamniotic Separation and Partial Placental Abruption

Amniotic band syndrome is a constrictive phenomenon in fetal development that can provoke limb autoamputation, malformation, trunk division, and umbilical cord strangulation. The latter two complications will ultimately lead to fetal demise if left untreated. If detected early enough, select cases may benefit from prenatal resection of the amniotic bands, thus preventing amputation and fetal death. Yet, especially in the presence of complete chorioamniotic separation, these procedures are rare, technically difficult, and not without significant risk.

OBJECTIVES

The purpose of this report is to present the surgical technique and outcome of a challenging percutaneous fetoscopic intervention in a human fetus with amniotic band constrictions of a fetal thigh, retroplacental hematoma, partial placental abruption, subtotal chorioamniotic separation, and multiple amniotic bands encircling the umbilical cord.

METHODS

Minimally invasive, fetoscopic surgery to salvage the fetal life and lower leg was performed at 22 + 2 weeks of gestation under general maternofetal anesthesia.

RESULTS

Total resection of all amniotic bands was achieved, notwithstanding the aforementioned challenges. No surgical complications were observed. Despite preterm delivery at 25 + 4 weeks of gestation, the postnatal experience for the infant was favorable and uncomplicated as it furthermore benefitted from neonatal intensive care. At almost three years of age, the child remains healthy and demonstrates normal function of the formerly constricted leg.

CONCLUSIONS

Our case shows that the combination of tested percutaneous fetoscopic techniques, high-risk obstetrics, and modern neonatology can overcome multiple obstacles in order to save a fetal patient stuck in a near-hopeless situation.

Advances in Fetal Surgical Repair of Open Spina Bifida

Spina bifida remains a common congenital anomaly of the central nervous system despite national fortification of foods with folic acid, with a prevalence of 2-4 per 10,000 live births. Prenatal screening for the early detection of this condition provides patients with the opportunity to consider various management options during pregnancy. Prenatal repair of open spina bifida, traditionally performed by the open maternal-fetal surgical approach through hysterotomy, has been shown to improve outcomes for the child, including decreased need for cerebrospinal fluid diversion surgery and improved lower neuromotor function. However, the open maternal-fetal surgical approach is associated with relatively increased risk for the patient and the overall pregnancy, as well as future pregnancies. Recent advances in minimally invasive prenatal repair of open spina bifida through fetoscopy have shown similar benefits for the child but relatively improved outcomes for the pregnant patient and future childbearing.

Minimally Invasive Bimanual Fetal Surgery—A Review

Background: The aim of this review is to discuss experimental and clinical techniques and interventions of fetal surgery which have been performed minimally invasively by the means of a three-port approach for the fetoscope and instruments for the left and right hand of the surgeon (bimanual minimally invasive fetal surgery). Methods: a print and electronic literature search was performed; the titles and abstracts were screened and included reports were reviewed in a two-step approach. First, reports other than minimally invasive fetal surgery were excluded, then a full text review and analysis of the reported data was performed. Results: 17 reports were included. The heterogeneity of the included reports was high. Although reports on human fetoscopic surgical procedures can be found, most of them do not pick out bimanual fetal surgery as a central theme but rather address interventions applying a fetoscope with a working channel for a laser fiber, needle or flexible instrument. Most reports were on experimentation in animal models, the human application of minimally invasive fetoscopic bimanual surgery is rare and has at best been explored for the prenatal treatment of spina bifida. Some reported bimanual fetoscopic procedures were performed on the exteriorized uterus via a maternal laparotomy and can therefore not be classified as being truly minimally invasive. Discussion: our results demonstrate that minimally invasive fetoscopic bimanual surgery is rare, even in animal models, excluding many other techniques and procedures that are loosely termed ‘minimally invasive fetal surgery’ which we suggest to better label as ‘interventions’. Thus, more research on percutaneous minimally invasive bimanual fetoscopic surgery is warranted, with the aim to reduce the maternal, uterine and fetal trauma for correction of congenital malformations.

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.

Postnatal Repair of Open Neural Tube Defects: A Single Center with 90-Month Interdisciplinary Follow-Up

After publication of the Management of Myelomeningocele Study (MOMS) there is confusion regarding which treatment of open neural tube defects (NTD) is best. We report our results of postnatally repaired open NTDs born between 2007–2018 (n = 36) in critical reflection of the MOMS study. Neurosurgical, orthopedic, and urologic data were assessed. We also introduce a new entity: “status post prenatal repair”. FU ranged from 29 to 161 months (mean: 89.1 m) in 7 cases of myeloschisis and 24 myelomeningoceles in the final collective n = 31. The shunt rate was 41.9%, and the endoscopic third ventriculostomy rate was 16.1%. Hydrocephalus requiring treatment was not associated with the anatomical level, but with premature birth (p = 0.048). Myeloschisis was associated with shunt placement (p = 0.008). ROC analysis revealed birth <38.5th week predicts the necessity for hydrocephalus treatment (sensitivity: 89%; specificity: 77%; AUC= 0.71; p = 0.055). Eight (25.8%), patients are wheelchair-bound, 2 (6.5%) ambulate with a posterior walker, 10 (32.3%) with orthosis and 11 (35.5%) independently. One (3.2%) patient underwent detethering at 5.5 years. A total of three patients underwent five Chiari decompressions (9.6%). Further, nineteen orthopedic procedures were performed in nine patients (29.0%). A total of 17 (54.8%) patients self-catheterize, which was associated with an anatomical lesion at L3 or below (p = 0.032) and 23 (74.2%) take anticholinergic medication. In conclusion, shunt dependency is associated with myeloschisis, not with the anatomical defect level. Hydrocephalus treatment is associated with premature birth. In this postnatal cohort with significantly longer follow-up data than the MOMs study, the ambulation rate is better, the shunt rate lower and the secondary tethered cord rate better compared to the MOMS study.

From non-invasive to invasive fetal therapy: A comprehensive review and current update

"Fetus as patient" indicates fundamental concept of fetal therapy. With advance in maternal serum analysis and fetal imaging, prenatal screening has become standard of care. Accurate diagnosis in early gestation allows intervention to reverse pathophysiology and delay progression immediately. Non-invasive, minimally invasive and invasive therapies demonstrate their therapeutic potential in certain diseases. Recently, stem cell and gene therapies have been developed to avoid irreversible impairment. To elevate efficacy of treatment modality, extensive studies should be conducted according to regulatory authority. Striking a balance between scientific and ethical integrity is essential, so long-term follow up should be arranged for protecting mother and fetus.

Modern fetal surgery-a historical review of the happenings that shaped modern fetal surgery and its practices

The history of fetal surgery is one of constant evolution. Over the last 50 years, fetal surgery has progressed from a mere idea to an internationally respected innovative field of surgery. This article aims to provide a historical review of how the enterprise of maternal-fetal surgery came to be its modern version. This review is less focused on the history of specific therapies for a relatively small number of conditions, and more on how the whole field of maternal-fetal surgery evolved. The various internal and external influences that steered the field's evolution are discussed in chronologic order. Since the start of modern fetal surgery in the 1980s, large paradigm shifts have characterized the growth of the field as a whole. Innovative interventions are now based on physiologic manipulation as opposed to simple anatomic repair, fetoscopy has become the more frequently preferred surgical approach, and rigorous scientific evaluation with randomized controlled trials is now the standard expected by the community. In a very similar fashion to when the field first began in the early 1980s, recently community's leaders have risen to protect the integrity of maternal-fetal surgery by publishing ethical guidelines for innovation and clinical practice. This incredible history of innovation, rigorous science and ethical contemplation is the foundation on which modern maternal-fetal surgery rests.

Fetoscopic myelomeningocoele closure: Is the scientific evidence enough to challenge the gold standard for prenatal surgery?

Since the completion of the Management of Myelomeningocoele Study, maternal-fetal surgery for spina bifida has become a valid option for expecting parents. More recently, multiple groups are exploring a minimally invasive approach and recent outcomes have addressed many of the initial concerns with this approach. Based on a previously published framework, we attempt to delineate the developmental stage of the surgical techniques. Furthermore, we discuss the barriers of performing randomized controlled trials comparing two surgical interventions and suggest that data collection through registries is an alternative method to gather high-grade evidence.

Prenatal Neural Tube Anomalies: A Decade of Intrauterine Stem Cell Transplantation Using Advanced Tissue Engineering Methods

Neural tube defects (NTDs) are among the most common congenital defects during neurulation. Spina bifida is a type of NTD that can occur in different forms. Since myelomeningocele (MMC) is the most severe form of spina bifida, finding a satisfactory treatment for MMC is a gold standard for the treatment of spina bifida. The Management of Myelomeningocele Study (MOMS) demonstrated that intrauterine treatment of spina bifida could ameliorate the complications associated with spina bifida and would also reduce the placement of ventriculoperitoneal (VP) shunt by 50%. Recently developed tissue engineering (TE) approaches using scaffolds, stem cells, and growth factors allow treatment of the fetus with minimally invasive methods and promising outcomes. The application of novel patches with appropriate stem cells and growth factors leads to better coverage of the defect with fewer complications. These approaches with less invasive surgical procedures, even in animal models with similar characteristics as the human MMC defect, paves the way for the modern application of less invasive surgical methods. Significantly, the early detection of these problems and applying these approaches can increase the potential efficacy of MMC treatment with fewer complications. However, further studies should be conducted to find the most suitable scaffolds and stem cells, and their application should be evaluated in animal models. This review intends to discuss advanced TE methods for treating MMC and recent successes in increasing the efficacy of the treatment.

Imaging of open spinal dysraphisms in the era of prenatal surgery

Over the last decade fetal surgery to repair open spinal dysraphisms has become an acceptable and in some cases desirable alternative to the traditional method of postnatal closure. Fetal MRI is an essential part of the workup in these patients, not only to select the appropriate candidates for fetal surgery but also to guide prenatal counseling and perinatal management. In this article we review current surgical techniques for prenatal repair, relevant imaging findings in the era of fetal surgery, and expected imaging findings of the brain and spine in the fetal and postnatal periods.

Retrieving the Moral in the Ethics of Maternal-Fetal Surgery

Open-uterine surgery to repair spina bifida, or 'fetal surgery of open neural tube defects,' has generated questions throughout its history-and continues to do so in a variety of contexts. As clinical ethics consultants who worked (Mark J. Bliton) and trained (Virginia L. Bartlett) at Vanderbilt University-where the first successful cases of open-uterine repair of spina bifida were carried out-we lived with these questions for nearly two decades. We worked with clinicians as they were developing and offering the procedure, with researchers in refining and studying the procedure, and with pregnant women and their partners as they considered whether to undergo the procedure. From this experience in the early studies at Vanderbilt, we learned that pregnant women and their partners approach the clinical uncertainty of such a risky procedure with a curious and unique combination of practicality, self-reflection, fear, and overwhelming hope. These early experiences were a major contributing factor to the inclusion of an ethics-focused interview in the informed consent process for the Management of Myelomeningocele Study (MOMS) trial study design.

Current perspective and scope of fetal therapy: part 1

Fetal therapy term has been described for any therapeutic intervention either invasive or noninvasive for the purpose of correcting or treating any fetal malformation or condition. Fetal therapy is a rapidly evolving specialty and has gained pace in last two decades and now fetal intervention is being tried in many malformations with rate of success varying with the type of different fetal conditions. The advances in imaging techniques have allowed fetal medicine persons to make earlier and accurate diagnosis of numerous fetal anomalies. Still many fetal anomalies are managed postnatally because the fetal outcomes have not changed significantly with the use of fetal therapy and this approach avoids unnecessary maternal risk secondary to inutero intervention. The short-term maternal risk associated with fetal surgery includes preterm labor, premature rupture of membranes, uterine wall bleeding, chorioamniotic separation, placental abruption, chorioamnionitis, and anesthesia risk. Whereas, maternal long-term complications include risk of infertility, uterine rupture, and need for cesarean section in future pregnancies. The decision for invasive fetal therapy should be taken after discussion with parents about the various aspects like postnatal fetal outcome without fetal intervention, possible outcome if the fetal intervention is done, available postnatal intervention for the fetal condition, and possible short-term and long-term maternal complications. The center where fetal intervention is done should have facility of multi-disciplinary team to manage both maternal and fetal complications. The major issues in the development of fetal surgery include selection of patient for intervention, crafting effective fetal surgical skills, requirement of regular fetal and uterine monitoring, effective tocolysis, and minimizing fetal and maternal fetal risks. This review will cover the surgical or invasive aspect of fetal therapy with available evidence and will highlight the progress made in the management of fetal malformations in last two decades.

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.

Foetal therapies and their influence on preterm birth

Foetal therapy aims to improve perinatal survival or to prevent severe long-term handicap. Foetal medicine opens a new territory by treating the foetus as a patient. The mother has nothing to gain in terms of health benefits, yet she is inherently also undergoing treatment. In utero foetal interventions can be divided into ultrasound-guided minimally invasive procedures, fetoscopic procedures and open hysterotomy procedures, which carry an inherent risk of ruptured membranes and preterm birth. In this review, we summarise the conditions that may benefit from foetal therapy and review the current therapies on offer, each with their associated risk of ruptured membrane and preterm birth. We also look into some risk limiting and preventative strategies to mitigate these complications.

Intra-Amniotic Delivery of CRMP4 siRNA Improves Mesenchymal Stem Cell Therapy in a Rat Spina Bifida Model

Neural tube defects (NTDs) result in prenatal mortality and lifelong morbidity, and available treatments have limited efficacy. We previously suggested that prenatal bone marrow-derived mesenchymal stem cell (BMSC) transplantation could treat neuron deficiency in NTD rats; however, BMSC-based therapy is limited by the low survival rate of BMSCs when used to treat severe NTDs. Herein, a new therapy using combined BMSC transplantation and small interfering RNA of collapsin response mediator protein 4 (CRMP4 siRNA), which was identified as a novel potential target for the NTD treatment, is proposed. The intra-amniotic CRMP4 siRNA, BMSC, and CRMP4 siRNA + BMSC injections repaired skin lesions, improved motor neural function, reduced neuronal apoptosis, and promoted expression of neural differentiation-related molecules and neurotrophic factors in the spinal cord of spina bifida rat fetuses. Therapeutic effects in the CRMP4 siRNA + BMSC injection group were superior to those of the CRMP4 siRNA only or BMSC only injection groups. CRMP4 siRNA + BMSC injection resulted in a 45.38% reduction in the skin lesion area and significantly shorter latency and higher amplitude of motor-evoked potentials (MEPs) in spina bifida fetuses. Our results suggest that intrauterine Ad-CRMP4 siRNA delivery with BMSCs is an innovative platform for developing fetal therapeutics to safely and efficaciously treat NTDs.

Fetal open spinal dysraphism repair through a mini-hysterotomy: Influence of gestational age at surgery on the perinatal outcomes and postnatal shunt rates

OBJECTIVE

To analyze the impact of gestational age (GA) at the time of fetal open spinal dysraphism (OSD) repair through a mini-hysterotomy on the perinatal outcomes and the infants' ventriculoperitoneal shunt rates.

METHODS

Retrospective study of cases of fetal OSD correction performed from 2014 and 2019.

RESULTS

One hundred and ninety women underwent fetal surgery for OSD through a mini-hysterotomy, and 176 (176/190:92.6%) have since delivered. Fetal OSD correction performed earlier in the gestational period, ranging from 19.7 to 26.9 weeks, was associated with lower rates of postnatal ventriculoperitoneal shunting (P: .049). Earlier fetal surgeries were associated with shorter surgical times (P: .01), smaller hysterotomy lengths (P < .001), higher frequencies of hindbrain herniation reversal (P: .003), and longer latencies from surgery to delivery (P < .001). Median GA at delivery was 35.3 weeks. Multivariate binary logistic regression showed that both fetal lateral ventricle-to-hemisphere ratio (%; P < .001; OR: 1.14 [95% CI: 1.09-1.21]) and GA at the time of fetal surgery (P: .016; OR: 1.37 [95% CI: 1.07-1.77]) were independent predictors of postnatal ventriculoperitoneal shunting.

CONCLUSION

Fetuses with OSD who were operated on earlier in the gestational interval, which ranged from 19.7 to 26.9 weeks, were less prone to receiving postnatal ventriculoperitoneal shunts.

Fetal repair of myelomeningocele: current status and urologic implications

Over the last 40 years, vast changes have occurred in the care of children with open neural tube defects. Not only has newborn survival dramatically improved but survival into adulthood has improved as well. Now, the ability to accurately identify and repair myelomeningocele (MMC) lesions before birth has become a reality. Pioneering efforts at several institutions in the United States paved the way for such advancements in care. Substantial data now exist to support the positive benefits of fetal MMC repair from a neurosurgical standpoint, chiefly the significant reduction in hindbrain herniation, decrease in shunt-dependent hydrocephalus, and improvement in lower-extremity motor function. However, until only recently, the urological impact of fetal repair has not been nearly as positive overall. Multiple retrospective reports of newborn bladder function from the United States suggest that prenatal repair has provided neither short-term nor long-term improvements in bladder function. Yet, the retrospective nature of these data and their focus upon urodynamic studies (UDS) parameters have hampered the ability to draw conclusions. Recently, published data from the landmark Management of Myelomeningocele Study indicate that fetal repair may improve certain aspects of bladder function when compared with conventional repair. This review provides an overview of the history and timeline of fetal repair in the United States and brings the reader quickly up to date on the current impact of repair on both neurosurgical and urological outcomes.

Prenatal and postnatal MRI findings in open spinal dysraphism following intrauterine repair via open versus fetoscopic surgical techniques

PURPOSE

The purpose of the study is to examine MRI findings of the brain and spine on prenatal and postnatal MRI following intrauterine repair of open spinal dysraphism (OSD) by open hysterotomy and fetoscopic approaches.

MATERIALS AND METHODS

This study is a single-center HIPAA-compliant and IRB-approved retrospective analysis of fetal MRIs with open spinal dysraphism from January 2011 through December 2018 that underwent subsequent prenatal repair of OSD.

RESULTS

Sixty-two patients met inclusion criteria: 47 underwent open repair, and 15 underwent fetoscopic repair, with an average gestational age of 22.6 ± 1.4 weeks at initial MRI. On postnatal MRI, spinal cord syrinx was seen in 34% (16/47) of patients undergoing open versus 33.3% (5/15) undergoing fetoscopic repair (P = 0.96). Postnatally, there was no significant difference in hindbrain herniation between the open versus fetoscopic repair groups (P = 0.28). Lateral ventricular size was significantly larger in the open (20.9 ± 6.7 mm) versus the fetoscopic repair (16.1 ± 4.9 mm) group (P = 0.01).

CONCLUSION

Though lateral ventricular size in the open repair group was larger than the fetoscopic repair group, this can likely be explained by initial selection criteria used for fetoscopic repair. Other postoperative imaging parameters on postnatal MRI were not significantly different between the two groups.

Advances in Fetal Surgery: Current and Future Relevance in Plastic Surgery

Scarless healing has long been the holy grail for plastic surgery. While historically fetal surgery has tempted plastic surgeons with the allure of scarless correction of congenital abnormalities, the risks far outweighed the benefits and these interventions never materialized. Current advances in fetal surgery with minimally invasive fetoscopic surgery have made these early fetal interventions safer, leading to expanding applications. While the plastic surgeon's role is limited as of yet, this article provides a review of the history of fetal surgery and the advances that may become relevant to the future plastic surgeon.

Biomaterials in fetal surgery

Fetal surgery and fetal therapy involve surgical interventions on the fetus in utero to correct or ameliorate congenital abnormalities and give a developing fetus the best chance at a healthy life. Historical use of biomaterials in fetal surgery has been limited, and most biomaterials used in fetal surgeries today were originally developed for adult or pediatric patients. However, as the field of fetal surgery moves from open surgeries to minimally invasive procedures, many opportunities exist for innovative biomaterials engineers to create materials designed specifically for the unique challenges and opportunities of maternal-fetal surgery. Here, we review biomaterials currently used in clinical fetal surgery as well as promising biomaterials in development for eventual clinical translation. We also highlight unmet challenges in fetal surgery that could particularly benefit from novel biomaterials, including fetal membrane sealing and minimally invasive myelomeningocele defect repair. Finally, we conclude with a discussion of the underdeveloped fetal immune system and opportunities for exploitation with novel immunomodulating biomaterials.

Fetal surgery for spina bifida

The two-hit hypothesis of neural injury in the wake of open neural tube defects suggests an opportunity for preservation of function and potential reversibility of early morphological changes in the fetus diagnosed with myelomeningocele. The Management of Myelomeningocele Study (MOMS) demonstrated reduced need for shunting and improved neurological function in patients treated in utero relative to postnatally, thereby offering level 1 evidence supporting fetal repair. Subsequent studies have offered additional information about urological, orthopedic, radiological, and maternal factors surrounding fetal repair. The quest for robust long-term neurocognitive and motor function data is underway and poised to shape the future of fetal repair. In addition, technical innovations such as fetoscopic surgery aim to minimize maternal morbidity while conferring the beneficial effects observed with open intrauterine intervention.

Spinal Dysraphia, Chiari 2 Malformation, Unified Theory, and Advances in Fetoscopic Repair

Fetal spina bifida, the most common nonlethal birth defect of the central nervous system, results in substantial neurologic morbidity. The unified theory describes the complex relationship between local spinal lesions and development of Chiari 2 malformation, contributing to hydrocephalus. Prenatal ultrasonography reliably allows diagnosis, but fetal MR imaging is an important complement to identify additional brain abnormalities. Fetal surgery improves neurologic and motor outcomes, but various approaches, either open hysterotomy or minimally invasive to the uterus, carry substantial obstetric risks. Optimization of the fetoscopic approach aims to minimize maternal and obstetric risks, but data regarding longer-term outcomes are awaited.

Fetoscopic spina bifida repair

INTRODUCTION

Spina bifida is the most common non-lethal congenital birth defect of the central nervous system that causes chronic disability due to the combined effects of local nerve damage and the sequelae of non-communicating hydrocephalus. This abnormality can be identified early in gestation and the damage can be progressive over the course of pregnancy. Advances in fetal treatment have made minimally invasive prenatal surgery a realistic consideration for spina bifida in order to improve the outcome for children affected this condition.

EVIDENCE ACQUISITION

Prenatal surgery for spina bifida via open fetal surgery with hysterotomy decreases the rate of ventriculoperitoneal shunt placement and improves motor function compared to standard postnatal surgery. Maternal risks of open fetal surgery are primarily related to complications of the hysterotomy including thinning or rupture that begins in the index pregnancy but persists for every future pregnancy. Minimizing maternal risks is the largest impetus to explore and optimize a minimally invasive fetoscopic alternative. Techniques vary from using a complete percutaneous approach to open fetoscopy, which requires laparotomy but is minimally invasive to the uterus. This allows vaginal delivery at term and no scar complications are reported thus far. Fetal short-term neurosurgical outcomes compare favorably with improvement in hindbrain herniation >70% and decreased need for treatment for hydrocephalus between 40-45% after prenatal surgery performed either fetoscopically or through open fetal surgery.

EVIDENCE SYNTHESIS

Maternal obstetric outcomes are superior for fetoscopic spina bifida repair compared to open fetal surgery and avoids the ongoing risk in future pregnancy. Neonatal and infant benefits appear equivalent. The open fetoscopic approach minimizes the risk of ruptured membranes and subsequent preterm delivery as opposed to a completely percutaneous procedure. International collaboration is ongoing to share experience and assess long term treatment effects.

CONCLUSIONS

Continued refinement of a minimally invasive strategy for prenatal treatment of spina bifida is necessary to maximize benefits to the child and further minimize maternal risks and preterm birth.

Fetal surgery for spina bifida aperta

Spina bifida aperta (SBA) is one of the most common congenital malformations. It can cause severe lifelong physical and neurodevelopmental disabilities. Experimental and clinical studies have shown that the neurological deficits associated with SBA are not simply caused by incomplete neurulation at the level of the lesion. Additional damage is caused by prolonged exposure of the spinal cord and nerves to the intrauterine environment and a suction gradient due to cerebrospinal fluid leakage, leading to progressive downward displacement of the hindbrain. This natural history can be reversed by prenatal repair. A randomised controlled trial demonstrated that mid-gestational maternal-fetal surgery for SBA decreases the need for ventriculoperitoneal shunting and hindbrain herniation at 12 months and improves neurological motor function at 30 months of age. This came at the price of maternal and fetal risks, the most relevant ones being increased prematurity and a persistent uterine corporeal scar. Recently minimally invasive fetal approaches have been introduced clinically yet they lack extensive experimental or clinical trials. We aim to provide clinicians with the essential information necessary to counsel SBA parents as the basis for considering referral of selected patients to expert fetal surgery centres. We review the reported clinical outcomes and discuss recent developments of potentially less invasive fetal SBA approaches.

Partial amniotic carbon dioxide insufflation for fetal surgery

Partial amniotic carbon dioxide insufflation (PACI) involves insufflating the amniotic sac with carbon dioxide (CO₂ ) and, in some cases, draining some of the amniotic fluid. The creation of a gaseous intra-amniotic compartment improves visualization, even in the presence of limited bleeding, and creates the work space required for complex fetoscopic procedures. Clinically, PACI is mostly used to perform fetoscopic myelomeningocele (MMC) repair, enabling a minimally invasive alternative to open fetal surgery. However, evidence of the fetal safety of PACI is limited. Previous animal experiments in sheep demonstrate that PACI induces fetal hypercapnia and acidosis with largely unknown short and longer term implications. In this review, we examine the literature for the physiological effects of intrauterine insufflation pressure, duration, humidity, and the role of maternal hyperventilation on fetal physiology and well-being.

Safety and efficacy of fetal surgery techniques to close a spina bifida defect in the fetal lamb model: A systematic review

OBJECTIVE

To determine the safety and efficacy of different neurosurgical techniques for closure of spina bifida (SB) in the fetal lamb model.

METHOD

Systematic review of studies reporting on fetal lambs undergoing induction and closure of SB compared with non-operated normal lambs (negative controls) and/or lambs not undergoing closure of the defect (positive controls). Primary outcomes were (1) survival at birth (safety) and/or (2) presence of Somatosensory Evoked Potentials on hind limbs and/or improvement in quantitative histological spinal cord findings and/or reversal of hindbrain herniation (efficacy).

RESULTS

Out of 1311, 36 full-text articles were eligible. Nineteen were included for quality assessment. Due to high bias, only 2 adequately powered studies were included in the final analysis. An open approach using a 2-layer closure (muscle flap or acellular-dermal-matrix patch plus skin) was the only safe (patch + skin) and effective (both techniques) technique for prenatal closure in this animal model. No comparable level of evidence was identified for other techniques.

CONCLUSION

The experimental literature on prenatal SB closure underscores the lack of standardization. At present, there is animal experimental evidence that a 2-layer closure by hysterotomy is safe and effective. This technique is currently clinically used in a subset of patients. As new clinical techniques are introduced, it would seem logic to preclinically validate them against this experimental standard.

Two-Port Fetoscopic Repair of Myelomeningocele in Fetal Lambs

OBJECTIVE

The aim of this study was to assess the feasibility and the effectiveness of a fetoscopic myelomeningocele (MMC) repair with a running single suture using a 2-port access in the sheep model.

METHODS

Eighteen fetuses underwent surgical creation of a MMC defect at day 75. Fetuses were then randomized into 3 groups. Four fetuses remained untreated (control group). In the other 14 fetuses, a prenatal repair was performed at day 90: 7 fetuses had an open repair (oMMC), and 7 fetuses had a fetoscopic repair (fMMC) using a single-layer running suture through a 2-port access. Lambs were sacrificed at term, and histological examinations were performed.

RESULTS

Hindbrain herniation was observed in all live lambs in the control group. A complete closure of the defect was achieved in all the lambs of the fMMC group. A complete healing of the defect and no hindbrain herniation were observed in all live lambs of the oMMC and fMMC groups. The durations of surgeries were not statistically different between the oMMC and the fMMC groups (60 vs. 53 min, p = 0.40), as was the risk of fetal loss (fMMC: 1/7, oMMC: 3/7, p = 0.56).

DISCUSSION

Fetoscopic repair of MMC can be performed using a single-layer running suture through a 2-port access and may be promising to reduce the risk of premature rupture of membranes.

Minimally Invasive Fetal Surgery

Fetal surgery corrects severe congenital anomalies in utero to prevent their severe consequences on fetal development. The significant risk of open fetal operations to the pregnant mother has driven innovation toward minimally invasive procedures that decrease the risks inherent to hysterotomy. In this article, we discuss the basic principles of minimally invasive fetal surgery, the general history of its development, specific conditions and procedures used to treat them, and the future of the field.

Maternal-fetal surgery for myelomeningocele: some thoughts on ethical, legal, and psychological issues in a Western European situation

BACKGROUND

The results of the Management of Myelomeningocele Study (MOMS) randomized controlled trial have demonstrated that maternal-fetal surgery (MFS) for myelomeningocele (MMC) compared to postnatal MMC repair has clear neurological benefits for the child at 12 and 30 months of age. Level I evidence nevertheless does not provide answers to many questions in this delicate field. Since the beginning of 2012, our fetal center has been offering MFS for spina bifida aperta (SBA) to patients from different European and non-European countries, in a societal context where termination of pregnancy is the option chosen by most patients when being informed of this diagnosis.

METHODS

We aim to explore in this text some of the ethical, legal, and psychological issues that we have encountered.

RESULTS

For many of these questions, we do not have definite answers. A pregnant patient when diagnosed with a MMC fetus is a vulnerable subject. She needs to be referred to a highly specialized center with sufficient expertise in diagnosis and in all therapeutic options. Objective but compassionate counseling is of paramount importance. It is required that a multidisciplinary professional team obtains full voluntary consent from the mother after providing an appropriate information including diagnosis, short-, medium-, and long-term prognosis as well as benefits and harms of the fetal surgery.

CONCLUSION

The latter should be offered with full respect for maternal choice and individual assessment and perception of potential risks taking into consideration legislation in the fetal center and the parents' country legislation.

Prenatal surgery for myelomeningocele: review of the literature and future directions

Open spina bifida or myelomeningocele (MMC) is one of the most common serious congenital malformations. Historically, this condition has been treated with closure of the MMC defect shortly after birth. The goal of postnatal closure is to cover the exposed spinal cord and prevent infection. However, postnatal surgery does not reverse or prevent the neurologic injury seen in MMC, reverse hindbrain herniation, or prevent hydrocephalus. The neurologic defects result from primary incomplete neurulation and secondary chronic prenatal damage to the exposed neural elements through mechanical and chemical trauma. In a hope to reduce the numerous surgical procedures, medical complications, and lifelong disabilities associated with MMC, the proposal of prenatal closure was put forth more than two decades ago. After promising results in animal models and some clinical series, a randomized controlled trial, the Management of Myelomeningocele Study (MOMS), was conducted. The MOMS trial demonstrated that closure during the prenatal period could be performed relatively safely and can result in significant benefit to the child. Specifically, prenatal closure results in improved motor function, reduced hindbrain herniation, and reduced need for a cerebral spinal fluid diversion. Long-term outcomes of the patients in the MOMS trial continues in the MOMS 2 study as these children grow. Additionally, investigations are underway on modifications to the open fetal MMC closure techniques.

Fetal surgery: a critical review

Therapeutic fetal surgical procedures are predicated upon the ability to make an accurate fetal diagnosis. The earliest open fetal surgical procedures were introduced in the 1960s to treat Rh isoimmunisation. They were introduced when it became possible to predict impending fetal demise. Open procedures were abandoned when percutaneous approaches proved superior. The introduction of fetal ultrasound allowed the diagnosis of other congenital anomalies, some being amenable to fetal interventions. Open fetal surgical procedures were initially utilised, with significant maternal morbidity. For some anomalies, percutaneous approaches became favoured. In general, all of these procedures involved significant risks to the mother, to save a baby that was likely to die before or shortly after birth without fetal intervention. Fetal repair for myelomeningocele was a "sea change" in approach. The same maternal risks were taken to improve the quality of life of the affected fetus, not save its life. The completion of the "MOMs Trial" has occasioned a "tsunami" of centres in North America applying this approach. Others are attempting percutaneous repairs, with mixed results. This paper reviews the history of fetal surgery, focusing on the themes of the tension between accurate diagnosis and prognosis and open versus "minimally invasive" approaches.

Procedure-related complications of open vs endoscopic fetal surgery for treatment of spina bifida in an era of intrauterine myelomeningocele repair: systematic review and meta-analysis

OBJECTIVE

To assess and compare the rate of procedure-related complications after intrauterine treatment of spina bifida by endoscopic surgery and by open fetal surgery.

METHODS

Systematic literature searches in PubMed and SCOPUS databases were performed on 20 September 2015 to identify randomized controlled trials and observational studies on treatment of human spina bifida by endoscopic or open fetal surgery techniques. Only studies with ≥ 10 cases that were published in or after 2000 were included in the meta-analysis in order to reduce the risk of bias. Primary outcomes (complete dehiscence, focal dehiscence and/or markedly thin hysterotomy scar; preterm delivery < 34 weeks; mean gestational age at delivery) and secondary outcomes (oligohydramnios, prelabor rupture of membranes, placental abruption, chorioamnionitis and perinatal death) were assessed for both techniques. Precision of the estimated proportions was evaluated with 95% CIs. Inconsistency was assessed using the I(2) statistic.

RESULTS

The search identified 1080 records that were examined based on title and abstract, of which 28 full-text articles were examined completely for eligibility. Nine records were excluded because cases were also described in other studies, leaving 19 records for analysis. When comparing endoscopic vs open fetal surgery, the rate of complete dehiscence, focal dehiscence and/or markedly thin hysterotomy scar was, respectively, 1% (95% CI, 0-4%) vs 26% (95% CI, 12-42%); preterm delivery < 34 weeks was 80% (95% CI, 41-100%) vs 45% (95% CI, 38-53%); oligohydramnios was 39% (95% CI, 9-75%) vs 14% (95% CI, 7-24%); prelabor rupture of membranes was 67% (95% CI, 12-100%) vs 38% (95% CI, 26-50%); and perinatal death was 14% (95% CI, 1-38%) vs 5% (95% CI, 3-8%).

CONCLUSION

Open fetal surgery for spina bifida seems to show lower rates of procedure-related complications than does endoscopic surgery, but the rate of hysterotomy scar complications is high after open surgery. Because of the low quality of evidence, the conclusions should be interpreted with caution. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Outcomes of infants followed-up at least 12 months after fetal open and endoscopic surgery for meningomyelocele: a systematic review and meta-analysis

OBJECTIVE

To assess the outcomes of infants followed-up at least 12 months after open and endoscopic fetal surgery for the treatment of spina bifida.

METHODS

A searching in The Cochrane Library, LILACS, PubMed and SCOPUS databases for fetal meningomyelocele (MMC) open or endoscopic surgery in humans from 2003 on-wards with follow-up at least 12 months. The rate of the estimated proportions was evaluated by the 95% confidence interval (CI).

RESULTS

A total of 19 studies were finally included (17 open and 2 endoscopic surgery). The results suggested that the rate for ventriculoperitoneal shunt placement were 40% (29%, 51%) versus 45% (34%, 56%) for open surgery group and endoscopic surgery group. The rate of hindbrain herniation reversal was 34% (28%, 52%) versus 86% (49%, 97%), the lower extremity function rates for both groups were 47% (30%, 64%) versus 86% (49%, 97%), and bladder dysfunction rates for both groups were 72% (53%, 88%) versus 29% (8%, 64%), respectively. Open and endoscopic fetal surgery for MMC presented similar ventriculoperitoneal shunt rates.

CONCLUSION

Open and endoscopic fetal surgery for MMC presented similar ventriculoperitoneal shunt rates in infants followed at least 12 months.

Fetoscopic versus Open Repair for Spina Bifida Aperta: A Systematic Review of Outcomes

Objective: To compare outcomes of fetoscopic spina bifida aperta repair (FSBAR) with the results of the open approach (OSBAR) as in the Management Of Myelomeningocele Study (MOMS). Methods: This was a systematic comparison of reports on FSBAR with data from the MOMS (n = 78). Inclusion criteria were studies of spina bifida aperta patients who underwent FSBAR and were followed for ≥12 months. Primary outcome was perinatal mortality. Secondary outcomes included operative, maternal, fetal, neonatal and infant outcomes. Results: Out of 16 reports, we included 5 from 2 centers. Due to bias and heterogeneity, analysis was restricted to two overlapping case series (n = 51 and 71). In those, FSBAR was technically different from OSBAR, had comparable perinatal mortality (7.8 vs. 2.6%, p = 0.212) and shunt rate at 12 months (45 vs. 40%, p = 0.619), longer operation time (223 vs. 105 min, p < 0.001), higher preterm prelabor membrane rupture rate (84 vs. 46%, p < 0.001), earlier gestational age at birth (32.9 vs. 34.1 weeks, p = 0.03), higher postnatal reoperation rate (28 vs. 2.56%, p < 0.001) and absence of uterine thinning or dehiscence (0 vs. 36%, p < 0.001). Functional outcomes were not available. Conclusion: FSBAR utilizes a different neurosurgical technique, takes longer to complete, induces more prematurity, requires additional postnatal procedures, yet has a comparable shunt rate and is not associated with uterine thinning or dehiscence. Long-term functional data are awaited.

Endoscopic surgery for the antenatal treatment of myelomeningocele: the CECAM trial

BACKGROUND

A recent randomized clinical trial named Management of Myelomeningocele Study (MOMS trial) showed that prenatal correction of open spina bifida (OSB) via open fetal surgery was associated with improved infant neurological outcomes relative to postnatal repair, but at the expense of increased maternal morbidity.

OBJECTIVE

We sought to report the final results of our phase I trial (Cirurgia Endoscópica para Correção Antenatal da Meningomielocele [CECAM]) on the feasibility, safety, potential benefits, and side effects of the fetoscopic treatment of OSB using our unique surgical technique.

STUDY DESIGN

Ten consecutive pregnancies with lumbosacral OSB were enrolled in the study. Surgeries were performed percutaneously under general anesthesia with 3 ports and partial carbon dioxide insufflation. After appropriate surgical positioning of the fetus, the neuroplacode was released with scissors and the skin was undermined to place a biocellulose patch over the lesion. The skin was closed over the patch using a single running stitch. Preoperative, postoperative, and postnatal magnetic resonance imaging were performed to assess hindbrain herniation. Neurodevelopmental evaluation was performed before discharge and at 3, 6, and 12 months. All cases were delivered by cesarean delivery, at which time the uterus was assessed for evidence of thinning or dehiscence.

RESULTS

The median gestational age at the time of surgery was 27 weeks (range 25-28 weeks). Endoscopic repair was completed in 8 of 10 fetuses. Two cases were unsuccessful due to loss of uterine access. The mean gestational age at birth was 32.4 weeks with a mean latency of 5.6 weeks between surgery and delivery (range 2-8 weeks). There was 1 fetal and 1 neonatal demise, and 1 unsuccessful case underwent postnatal repair. Of the 7 infants available for analysis, complete reversal of hindbrain herniation occurred in 6 of 7 babies. Three babies required ventriculoperitoneal shunting or third ventriculostomy. Functional motor level was the same or better than the anatomical level in 6 of 7 cases. There was no significant maternal morbidity and no evidence of myometrial thinning or dehiscence. However, surgeries were complicated by premature rupture of membrane and prematurity.

CONCLUSION

Our study suggests that the antenatal treatment of OSB using a fetoscopic approach and our unique surgical technique can result in a watertight seal, reversal of the hindbrain herniation, and better than expected motor function. Our technique differs substantially from the classic repair of OSB used in prior open fetal surgery and fetoscopic studies, in which the dura mater is dissected and the defect is closed in multiple layers. Instead, we use a biocellulose patch placed over the lesion and simple closure of the skin. As such, our technique is an alternative to the current paradigms in the antenatal treatment of OSB. Our clinical outcomes are in line with the results of our extensive prior animal work. Maternal benefits of our approach and technique include minimal morbidity and no myometrial legacy. Current limitations of the approach include potential loss of access, premature rupture of membranes, and attendant prematurity. Phase II trials are needed to prevent these complications and to further assess the risks and benefits of our distinct surgical approach and technique.

Evaluation and Management of Lumbosacral Myelomeningoceles in Children

OBJECTIVE

Myelomeningoceles are the common form of open neural tube defects that are usually associated with neurological deficits. Many techniques of repair and methods of prevention have been proposed with respect to the size of defect and the neurological condition of patient. The aim of this study was to report our experience on the management of lumbosacral myelomeningoceles in children.

MATERIALS AND METHODS

We retrospectively analysed the data of 36 paediatric cases of surgically lumbosacral myelomeningocele treated in our department between 1998 and 2013. Twenty (56%) patients were female and sixteen were male, with a mean age of 4 months (ranged between 0 and 24 months). All patients had neurological deficits in the preoperative period. Computed tomography was performed in 33 (92%) patients and magnetic resonance imaging in 15 (42%) patients in the preoperative period. Repair of the myelomeningocele and closure of the skin defect were performed in all patients. The mean follow-up period was 36 months.

RESULTS

Thirty (83%) patients were operated for hydrocephalus and 10 (28%) patients were re-operated for tethered cord syndrome during the follow-up period. Neurological worsening was not observed in any patient while cerebrospinal fluid fistula was detected in 2 patients.

CONCLUSION

Surgical treatment using appropriate microsurgical techniques is crucial for lumbosacral myelomeningoceles in children. Early surgical intervention with close follow-up will improve the neurological condition of the patients.

Fetal surgery: principles, indications, and evidence

Since the first human fetal surgery was reported in 1965, several different fetal surgical procedures have been developed and perfected, resulting in significantly improved outcomes for many fetuses. The currently accepted list of fetal conditions for which antenatal surgery is considered include lower urinary tract obstruction, twin-twin transfusion syndrome, myelomeningocele, congenital diaphragmatic hernia, neck masses occluding the trachea, and tumors such as congenital cystic adenomatoid malformation or sacrococcygeal teratoma when associated with developing fetal hydrops. Until recently, it has been difficult to determine the true benefits of several fetal surgeries because outcomes were reported as uncontrolled case series. However, several prospective randomized trials have been attempted and others are ongoing, supporting a more evidence-based approach to antenatal intervention. Problems that have yet to be completely overcome include the inability to identify ideal fetal candidates for antenatal intervention, to determine the optimal timing of intervention, and to prevent preterm birth after fetal surgery. Confronting a fetal abnormality raises unique and complex issues for the family. For this reason, in addition to a maternal-fetal medicine specialist experienced in prenatal diagnosis, a pediatric surgeon, an experienced operating room team including a knowledgeable anesthesiologist, and a neonatologist, the family considering fetal surgery should have access to psychosocial support and a bioethicist.