Prenatal Diagnosis of Robin Sequence: Sensitivity, Specificity, and Clinical Relevance of an Index for Micrognathia

Evaluating Prenatal Diagnostic Imaging for Micrognathia: A Systematic Review and Meta-Analysis

OBJECTIVE

Studies evaluating the ability to diagnose and accurately predict the severity of micrognathia prenatally have yielded inconsistent results. This review aimed to evaluate reliability of prenatal diagnostic imaging in the diagnosis and characterization of micrognathia.

DESIGN

Systematic review and meta-analysis.

SETTING

Studies with a prenatal diagnosis of micrognathia via ultrasound with a confirmatory postnatal examination were included. Prenatal severity was defined with and without mandibular measurements. Extent of airway obstruction at birth was defined by level of intervention required. Meta-analyses of proportions and relative risk were performed.

PATIENTS

A total of 16 studies with 2753 neonates were included.

MAIN OUTCOME MEASURES

Primary outcome was the efficacy of characterizing the degree of micrognathia on prenatal imaging as it relates to respiratory obstruction at birth. Secondary outcome was the accuracy of prenatal diagnosis with the utilization of mandibular measurements versus without.

RESULTS

Performing meta-analysis of proportions, the proportion of missed prenatal diagnoses of micrognathia made without mandibular measurements was 11.62% (95%CI 2.58-25.94). Utilizing mandibular measurements, the proportion of cases missed were statistically lower (0.20% [95%CI 0.00-0.70]). Patients determined to have severe micrognathia by prenatal imaging did not have a statistically significant increase in risk for more severe respiratory obstruction at birth (RR 3.13 [95%CI 0.59-16.55], P = .180).

CONCLUSION

The proportion micrognathia cases missed when prenatal diagnosis was made without mandibular measurements was over 1 in 10, with mandibular measures improving accuracy. This study highlights the need for a uniform objective criterion to improve prenatal diagnosis and planning for postnatal care.

Diagnosis and Early Management of Robin Sequence

The results of a survey of twenty-four neonatal units in the United Kingdom and Ireland are presented. A structured ten-item questionnaire was used, and demonstrated the variation in how infants with RS are diagnosed and managed. Notably, the survey revealed that a minority of infants were diagnosed antenatally. There were significant discrepancies in diagnostic criteria used and 79% of the units referred the patients to tertiary services. A preference for minimally invasive approaches to managing upper airway obstruction, such as a trial of prone positioning before progressing to a nasopharyngeal airway, was reported by 96% of the centers. A narrative review was undertaken which discusses the current practices for diagnosis and early management of Robin sequence (RS). The challenges of antenatal diagnosis, strategies to enhance outcomes through early detection and controversies surrounding the management of neonatal upper airway obstruction associated with RS are included. The results of the survey and our comprehensive review of the literature emphasize that there remains uncertainty regarding the best approach to treating Robin sequence.

The Family Impact of a Robin Sequence Prenatal Diagnosis

OBJECTIVE

Assess the impact of prenatal diagnosis of Robin sequence (RS) on parental experience during gestation and early infancy.

DESIGN

Prospective case-control study. An online survey was administered via email to 44 parents representing 34 unique patients with RS.

PARTICIPANTS

Parents of children diagnosed with RS and who received mandibular distraction at our tertiary care children's hospital. Participants were separated by the timing of RS diagnosis into prenatal and control postnatal groups.

MAIN OUTCOME MEASURES

Effects of timing of diagnosis on parents' preparation, caregiver support, education about the condition, stress, and overall mental health.

RESULTS

Complete responses were received from 44 parents representing 34 unique patients (50% response rate): prenatal, n = 17; postnatal, n = 27. Prenatal diagnosis improved parents' satisfaction regarding time to prepare for treatment (P = .001), stress of uncertainty about their child's health (P = .018), and stress about the operation(s) their child would need (P = .001). Both the prenatal (82%) and postnatal (78%) groups reported a negative impact on mental health based on diagnosis timing. All parents in the prenatal group preferred having received a prenatal diagnosis and the majority of the postnatal group (85%) would have preferred to have received the diagnosis prenatally.

CONCLUSIONS

Prenatal diagnosis of RS provided tangible benefits for parents by allowing them to mentally prepare, make plans for delivery and treatment, and become educated about the condition. Parents in both groups reported a negative impact on their mental health based on diagnosis timing and the majority of parents consistently preferred prenatal diagnosis.

Fetal Profile Markers for the Detection of Robin Sequence in Fetuses with Retrognathia

OBJECTIVE

To determine whether the prefrontal space ratio (PSFR), inferior facial (IFA) and maxilla-nasion-mandible angle (MNM), and the fetal profile line (FPL) are helpful in identifying fetuses with Robin sequence (RS) in cases with isolated retrognathia, and thus better predict the likelihood of immediate need for postnatal respiratory support.

METHODS

This was a retrospective matched case-control study of fetuses/infants with isolated retrognathia with or without RS receiving pre- and postnatal treatment at the University Hospital of Tübingen, Germany between 2008 and 2020. The PFSR, IFA, MNM, and FPL were measured in affected and normal fetuses according to standardized protocols. Cases were stratified into isolated retrognathia and RS.

RESULTS

21 (n=7 isolated retrognathia, n=14 RS) affected fetuses and 252 normal fetuses were included. Their median gestational age at ultrasound examination was 23.6 and 24.1 weeks, respectively. In fetuses with isolated retrognathia and RS, the PSFR, IFA, and FPL were significantly different from the normal population. At a false-positive rate of 5%, the detection rate was 76.2% for the PFSR, 85.7% for the IFA, and 90.5% for both parameters combined. However, all parameters failed to distinguish between isolated retrognathia and RS.

CONCLUSION

PSFR and IFA are simple markers for identifying retrognathia prenatally. However, they are not helpful for the detection of RS in fetuses with isolated retrognathia. Therefore, delivery should take place in a center experienced with RS and potentially life-threatening airway obstruction immediately after birth.

Prenatal diagnosis of micrognathia: a systematic review

Purpose

This systematic review aimed to analyze the characteristics of different diagnostic techniques for micrognathia, summarize the consistent diagnostic criteria of each technique, and provide a simple and convenient prenatal diagnosis strategy for micrognathia.

Methods

In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the search was undertaken in three international databases (PubMed, Scopus, and Web of Science). The three reviewers assessed all papers and extracted the following variables: author's name and year of publication, country, study design, number of participants, gestational age, equipment for prenatal examination, biometric parameters related to micrognathia, main results.

Results

A total of 25 articles included in the analysis. Nineteen articles described cross-sectional studies (76 percent), 4 (16 percent) were case-control studies, and 2 (8 percent) were cohort studies. Fifteen studies (60 percent) had a prospective design, 9 (36 percent) had a retrospective design, and one (4 percent) had both prospective and retrospective design. Thirty-two percent of the studies (n = 8) were performed in USA, and the remaining studies were performed in China (n = 4), Israel (n = 3), Netherlands (n = 3), UK (n = 1), France (n = 1), Italy (n = 1), Belgium(n = 1), Germany (n = 1), Spain (n = 1), and Austria (n = 1). The prenatal diagnosis of micrognathia can be performed as early as possible in the first trimester, while the second and third trimester of pregnancy were the main prenatal diagnosis period. The articles that were included in the qualitative synthesis describe 30 biometric parameters related to the mandible.

Conclusion

Of the 30 biometric parameters related to the mandible, 15 can obtain the simple and convenient diagnostic criteria or warning value for micrognathia. Based on these diagnostic criteria or warning value, clinicians can quickly make a preliminary judgment on facial deformities, to carry out cytologic examination to further clarify the diagnosis of micrognathia.

Disrupted tenogenesis in masseter as a potential cause of micrognathia

Micrognathia is a severe craniofacial deformity affecting appearance and survival. Previous studies revealed that multiple factors involved in the osteogenesis of mandibular bone have contributed to micrognathia, but concerned little on factors other than osteogenesis. In the current study, we found that ectopic activation of Fgf8 by Osr2-cre in the presumptive mesenchyme for masseter tendon in mice led to micrognathia, masseter regression, and the disrupted patterning and differentiation of masseter tendon. Since Myf5-cre;Rosa26R-Fgf8 mice exhibited the normal masseter and mandibular bone, the possibility that the micrognathia and masseter regression resulted directly from the over-expressed Fgf8 was excluded. Further investigation disclosed that a series of chondrogenic markers were ectopically activated in the developing Osr2-cre;Rosa26R-Fgf8 masseter tendon, while the mechanical sensing in the masseter and mandibular bone was obviously reduced. Thus, it suggested that the micrognathia in Osr2-cre;Rosa26R-Fgf8 mice resulted secondarily from the reduced mechanical force transmitted to mandibular bone. Consistently, when tenogenic or myogenic components were deleted from the developing mandibles, both the micrognathia and masseter degeneration took place with the decreased mechanical sensing in mandibular bone, which verified that the loss of mechanical force transmitted by masseter tendon could result in micrognathia. Furthermore, it appeared that the micrognathia resulting from the disrupted tenogenesis was attributed to the impaired osteogenic specification, instead of the differentiation in the periosteal progenitors. Our findings disclose a novel mechanism for mandibular morphogenesis, and shed light on the prevention and treatment for micrognathia.

Epidemiology of Pierre-Robin sequence in Europe: A population-based EUROCAT study

BACKGROUND

Pierre Robin sequence (PRS) is a rare congenital anomaly. Respiratory disorders and feeding difficulties represent the main burden.

OBJECTIVE

The aim of this study was to investigate the epidemiology of PRS using a cohort of cases from EUROCAT, the European network of population-based registries of congenital anomalies.

METHODS

We analysed cases of PRS born in the period 1998-2017 collected by 29 population-based congenital anomaly registries in 17 different countries. We calculated prevalence estimates, prenatal detection rate, survival up to 1 week, and proportions of associated anomalies. The effect of maternal age was tested using a Poisson regression model.

RESULTS

Out of 11 669 155 surveyed births, a total of 1294 cases of PRS were identified. The estimate of the overall prevalence was 12.0 per 100 000 births (95% CI 9.9, 14.5). There was a total of 882 (68.2%) isolated cases, and the prevalence was 7.8 per 100 000 births (95% CI 6.7, 9.2). A total of 250 cases (19.3%) were associated with other structural congenital anomalies, 77 cases (6.0%) were associated with chromosomal anomalies and 77 (6.0%) with genetic syndromes. The prenatal detection rate in isolated cases was 12.0% (95% CI 9.8, 14.5) and increased to 16.0% (95% CI 12.7, 19.7) in the sub-period 2008-2017. The prevalence rate ratio of non-chromosomal cases with maternal age ≥35 was higher than in cases with maternal age <25 for total (PRR 1.26, 95% CI 1.05, 1.51) and isolated cases (PRR 1.33, 95% CI 1.00, 1.64). Survival of chromosomal cases (94.2%) and multiple anomaly cases (95.3%) were lower than survival of isolated cases (99.4%).

CONCLUSIONS

This epidemiological study using a large series of cases of PRS provides insights into the epidemiological profile of PRS in Europe. We observed an association with higher maternal age, but further investigations are needed to test potential risk factors for PRS.