British Journal of Radiology 75 (2002),584-589 © 2002 The British Institute of Radiology
Sensitivity and accuracy of routine antenatal ultrasound screening for isolated facial clefts
C Wayne, MRCOG
K Cook, DCRR, DMU
S Sairam, MRCOG
B Hollis, MRCOG
and
B Thilaganathan, MC, MRCOG
Fetal Medicine Unit, Academic Department of Obstetrics and Gynaecology, St George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, UK
Correspondence: Dr B Thilaganathan
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Abstract
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Facial clefts, as a group, represent one of the most frequently occurring congenital abnormalities detectable on prenatal mid-trimester scan. It has been estimated that, at term, approximately 1 in 1000 infants will be diagnosed with an isolated facial cleft. The aim of this study was to determine the sensitivity and accuracy of routine second trimester ultrasound screening for facial clefts. This was a prospective study of isolated fetal facial clefts, detected at 18–23 weeks gestation, in a routine obstetric population. The antenatal detection rate of facial clefts was derived by comparing the number of cases identified antenatally with the number of neonatal cleft surgeries performed in this centre, for the local population only. The accuracy of antenatal diagnosis of facial clefts was calculated by matching data from the ultrasound database to birth registries and neonatal cleft surgeries performed in this centre, including the referred cases. During the study period, 17 551 women underwent a routine anomaly scan at 18–23 weeks of gestation. A total of 30 babies underwent surgery for isolated facial cleft in this centre during that period. There were no false positive diagnoses of facial clefts, and in five cases (all unilateral), the antenatal diagnosis was found to be inaccurate. 12 babies were from the local population, of which 9 had an antenatal diagnosis of facial cleft, giving a sensitivity of 75%. The current study highlights the effectiveness of antenatal screening for facial clefts. Additionally, it highlights the appropriate terminology that needs to be used in the accurate description of antenatally diagnosed facial clefts.
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Introduction
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Facial clefts encompass a variety of disorders affecting the lip, alveolus and hard and soft palates, either unilaterally or bilaterally. As a group, they represent one of the most frequently occurring congenital abnormalities detectable on prenatal mid-trimester ultrasound. It has been estimated that, at term, approximately 1 in 1000 infants will be diagnosed with an isolated facial cleft [1–9].
Although the prenatal detection of fetal facial clefts is associated with considerable parental anxiety, it is valuable in preparing the parents emotionally for the birth of a child with an anomaly [8, 9]. Parents also benefit from antenatal consultations with members of the multidisciplinary cleft management team, who will be responsible for the care of the neonate [8, 9]. However, information relating to the sensitivity and accuracy of antenatal detection is limited because previous studies were conducted on small, pre-selected populations, and with a lack of uniformity in ultrasound diagnostic criteria.
The aim of this study was to determine the sensitivity and accuracy of routine second trimester ultrasound screening for facial clefts.
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Patients and methods
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This was a prospective study carried out between January 1996 and December 2000 on an unselected obstetric population. During the study period, 17 551 patients underwent a routine detailed anomaly scan between 18 weeks and 23 weeks of gestation. As part of the routine structural survey, the facial profile, lips, alveolus and palate were carefully examined, looking for evidence of a facial cleft using both tangential and transverse views (Figures 1–6, showing the normal and abnormal
). In view of the results of a previous study conducted within our unit, anomaly scans were booked for 20–22 weeks gestation [10]. At this stage of pregnancy, recall rates because of unsatisfactory views of the face were 2% [10]. Anomaly scans were allocated 20 min time slots.
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Figure 3. Diagrammatic representation of the normal fetal upper lip and maxillary alveolar ridge in the axial plane.
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When a facial cleft was identified, the mother was referred to the Fetal Medicine Team for further investigation. A detailed scan was performed to confirm the position and extent of the cleft, as well as the presence of any associated anomalies. All women were of fered the option offetal karyotyping. Only those fetuses with an isolated cleft were included in the study. The postnatal management of these pregnancies was planned in conjunction with the neonatologists, paediatric plastic surgeons, speech therapists and parents. Further counseling was offered to parents when requested.
A computerized database search of all ultrasound scans containing facial clefts was performed to identify cases detected and assessed antenatally. This data was matched to birth registers and to neonatal cleft repairs performed in this unit. All neonatal cleft repairs for the surrounding region are performed in our centre, ensuring good postnatal ascertainment of cases in this study. Cases missed by routine antenatal ultrasound were identified from surgical records, which also provided details on the extent of facial clefting. Post-mortem records were identified to exclude any stillbirths with isolated facial clefts.
Sensitivity of routine ultrasound screening
Only patients booked for pregnancy care with this unit were included in the analysis to determine the prevalence and detection rate of facial clefts. The latter was determined by comparing the number of facial clefts identified antenatally to those diagnosed and repaired in the postnatal period.
Accuracy of antenatal ultrasound
All patients (local and referred) seen in the Fetal Medicine Unit for isolated facial clefts were included in this part of the study to ascertain the accuracy of antenatal diagnosis. The accuracy of scans was determined by comparing antenatal diagnosis with intra-operative findings.
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Results
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Prevalence of isolated facial clefts
During the study period 22 facial clefts (12 isolated) were identified, making the overall prevalence 1.3 in 1000 (0.13%) infants and the prevalence of isolated clefts 1 in 1500 (0.07%) infants. 10 cases with either associated multiple malformations or abnormal karyotypes were excluded from the study. None of the patients with isolated facial clefts opted for karyotyping or termination of the pregnancy.
Sensitivity of routine antenatal screening
In the routinely screened population, 12 neonates underwent surgery for facial clefts. Nine of these clefts (75%) were identified in the antenatal period (Table 1). Of the three facial clefts missed on routine antenatal ultrasound, all were unilateral; one a small incomplete cleft of the vermilion, one an isolated cleft palate and the third a cleft of the lip and palate (Table 1, cases 10–12).
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Table 1. List of cases with isolated facial clefts showing laterality of lesion and sensitivity of antenatal ultrasound
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Accuracy of antenatal ultrasound
During the study period, 30 neonates (12 local, 18 referred) underwent surgery for facial cleft. Of these, 26 neonates had an antenatal diagnosis and detailed assessment of the facial cleft. Antenatal diagnosis was found to be inaccurate in five cases giving an accuracy of 80.7% (Table 2). There were no false positive diagnoses of facial clefts.
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Discussion
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This is one of the largest, single centre prospective studies of ultrasound screening for facial clefts in an unselected routine obstetric population. It provides valuable information on the prevalence, classification, sensitivity and accuracy of antenatal ultrasound screening for facial clefts.
Prevalence
The prevalence of all fetal facial clefts in our study population at 18–23 weeks was 1.3 in 1000 (0.13%) infants. The prevalence of isolated facial clefts was 1 in 1500 (0.07%) infants, which is comparable to quoted prevalence rates of 0.07% to 0.15% (Table 3) [1–9]. Variation in prevalence rates from previous studies can be partly explained in antenatal studies by the inclusion of fetuses with associated multiple abnormalities. Postnatal follow-up studies often do not quote prevalence rates, as the population denominator remains unknown.
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Table 3. Cleft lip and palate studies showing, where available, the population studied, prevalence and antenatal sensitivity of ultrasound for both isolated and total facial clefts (isolated clefts plus clefts associated with other findings)
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Sensitivity of antenatal screening
The sensitivity of antenatal detection for isolated facial clefts in this study using transabdominal scan in a routine obstetric population was 75%. The only other study quoting a high sensitivity (9 in 14 cases; 57%) infants is that of Pilu et al [1], which looked at a high risk referred population scanned in a specialist unit. Additionally, the gestational age in that study ranged from 18–40 weeks, and 21% of patients required a repeat ultrasound scan to complete the facial examination. A more recent multicentre study has shown that even in the presence of other congenital abnormalities, only 34% of facial clefts were diagnosed antenatally and the sensitivity for detection of isolated facial clefts was much lower (14%) [2]. Most other studies have poor antenatal detection rates varying from 16% to 33% [3–9]. These low detection rates may be because evaluation of the fetal face is not routinely performed in low risk ultrasound screening in most countries. Only in 2000 did the Royal College of Obstetricians and Gynae<1?show=[fo]>cologists recommend views of the face and lips as part of the routine structural survey in fetal anomaly scans, resources permitting [11].
The higher detection rate in our study is attributable to the routine inclusion of specific views, namely tangential and transverse, of the fetal face during routine anomaly scan. Obtaining satisfactory views in these planes depends on the position of the fetal head, i.e. ideally occipitoposterior. However, most fetuses are quite mobile at this stage of pregnancy and, from our experience, it is relatively easy to obtain these views. Previous authors have suggested the use of auxiliary signs, namely pseudoprognathism and paranasal echogenic mass, to improve the detection rate of clefts of the lip, but these are yet to be validated in large-scale studies [12, 13]. The use of transvaginal scan may increase sensitivity, but the practicality and acceptability of an additional visit for a transvaginal scan needs to be considered [14]. Additionally, transvaginal scans would not provide more information if the fetus were to be in breech presentation or if the fetal face was away from the transducer.
Prenatal screening for chromosomal abnormalities is now possible in the first trimester using nuchal translucency risk assessment [15]. Therefore the 18–23 weeks anomaly scan should concentrate on identifying structural defects like congenital heart defects, neural tube defects and facial clefts. The value of identifying minor soft markers for chromosomal abnormality is becoming increasingly questionable in obstetric populations that have had prior screening for Down's syndrome [16, 17].
Accuracy of screening and classification of clefts
The accuracy of antenatal ultrasound diagnosis in this study was 81%. In the majority of cases, misdiagnosis was a direct consequence of the use of incorrect terminology. In transverse views of the fetal face at the level of the upper lip, only the alveolus (the teeth-bearing portion of the maxilla), and not the fetal palate, is readily visualized. This is often erroneously reported as clefting of the palate, leading to the discrepancy between the antenatal ultrasound descriptions and postnatal surgical findings. Failure to detect clefting of the palate is primarily due to difficulty in antenatal visualization of the posterior hard palate, which is often obscured by acoustic shadows from the maxillary alveolar ridge. Indeed Shaikh et al [9] excluded isolated clefts of the palate from their study as it is generally accepted that this abnormality cannot be detected on antenatal ultrasound. The accuracy of the current study is comparable to the 75% quoted by Benecerraf et al [18], even though these authors only assessed the accuracy of antenatal diagnosis of cleft lip alone, rather than palate.
Traditionally, facial clefts are classified by plastic surgeons as cleft of the lip with or without involvement of the palate. This classification is very useful postnatally to predict the extent of surgery likely to be required by the neonate, and also to envisage the impact on development of speech and hearing in the infant. Involvement of the palate, for instance, often leads to feeding and speech difficulties and generally requires a later and more complex surgical repair. Antenatally, it would suffice to warn prospective parents about the possibility of posterior palatal involvement that cannot, in most cases, be confirmed at the antenatal scan.
Conclusion
This study highlights the need for setting standards to include specific views of the fetal face in the routine anomaly scan, nationally or for individual units, to improve antenatal detection rates of facial clefts. Antenatal diagnosis followed by parental counseling by the cleft team improves the psychological aspect of cleft care and infuses parents with a positive approach towards their child. The accuracy of antenatal diagnosis may be improved by the use of appropriate terminology relating to structures that are seen at the time of screening. Incorrect antenatal labelling of alveolar clefts as cleft palate will lead to the wrong information being provided to parents and discrepancies in postnatal findings. Accurate description of the defect would promote a realistic expectation in the parents and in the team responsible for managing the neonate.
Received for publication November 20, 2001.
Revision received April 2, 2002.
Accepted for publication April 23, 2002.
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References
|
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- Pilu G, Reece A, Romero R, Bovicelli L, Hobbins JC. Prenatal diagnosis of craniofacial malformations with ultrasonography. Am J Obstet Gynecol 1986;155:45–50.[Medline]
- Clementi M, Tenconi R, Bianchi F, Stoll C. Evaluation of prenatal diagnosis of cleft lip with or without cleft palate and cleft palate by ultrasound: experience from 20 European registries. EUROSCAN study group. Prenat Diagn 2000;20:870–5.[Medline]
- Levi S, Hyjazi Y, Schaaps JP, Defoort P, Coulon R, Buekens P. Sensitivity and specificity of routine antenatal screening for congenital anomalies by ultrasound: the Belgian multicentric study. Ultrasound Obstet Gynecol 1991;1:102–10.[Medline]
- Shirley IM, Bottomley F, Robinson VP. Routine radiographer screening for fetal abnormalities by ultrasound in an unselected low risk population. Br J Radiol 1992;65:564–9.[Abstract/Free Full Text]
- Tolarova MM, Cervenka J. Classification and birth prevalence of orofacial clefts. Am J Med Genet 1998;75:126–37.[Medline]
- Matthews MS, Cohen M, Viglione M, Brown AS. Prenatal counseling for cleft lip and palate. Plast Reconstr Surg 1998;101:1–5.[Medline]
- Stoll C, Alembik Y, Dott B, Roth MP. Associated malformations in cases with oral clefts. Cleft Palate Craniofac J 2000;37:41–7.[Medline]
- Davalbhhakta A, Hall PN. The impact of antenatal diagnosis on the effectiveness and timing of counselling for cleft lip and palate. Br J Plast Surg 2000;53:298–301.[Medline]
- Shaikh D, Mercer NS, Sohan K, Kyle P, Soothill P. Prenatal diagnosis of cleft lip and palate. Br J Plast Surg 2001;54:288–9.[Medline]
- Schwarzler P, Senat MV, Holden D, Bernard JP, Masroor T, Ville Y. Feasibility of the second-trimester fetal ultrasound examination in an unselected population at 18, 20 or 22 weeks of pregnancy: a randomized trial. Ultrasound Obstet Gynecol 1999;14:92–7.[Medline]
- Royal College of Obstetricians and Gynaecologists Working Party. Routine ultrasound screening in pregnancy—protocol, standards and training. A Working Party Report by the Royal College of Obstetricians and Gynaecologists. London: RCOG Press, 2000.
- Nyberg DA, Mahony BS, Kramer D. Paranasal echogenic mass: sonographic sign of bilateral complete cleft lip and palate before 20 menstrual weeks. Radiology 1992;184:757–9.[Abstract/Free Full Text]
- Bronshtein M, Mashiah N, Blumenfeld I, Blemenfeld Z. Pseudoprognathism—an auxiliary ultrasonographic sign for transvaginal ultrasonographic diagnosis of cleft lip and palate in the early second trimester. Am J Obstet Gynecol 1991;165:1314–6.[Medline]
- Bronshtein M, Blumenfeld I, Kohn J, Blumenfeld Z. Detection of cleft lip by early second-trimester transvaginal sonography. Obstet Gynecol 1994;84:73–6.[Medline]
- Snijders RJM, Noble P, Sebire N, Souka A, Nicolaides KH. UK multicentre project on assessment of risk of trisomy 21 by maternal age and fetal nuchal translucency thickness at 10–14 weeks of gestation. Lancet 1998;351:343–6.
- Thilaganathan B, Olawaiye A, Sairam S, Harrington K. Isolated fetal echogenic intracardiac foci or golf balls: is karyotyping for Down's syndrome indicated? Br J Obstet Gynaecol 1999;106:1294–7.[Medline]
- Thompson MO, Thilaganathan B. Effect of routine screening for Down's syndrome on the significance of isolated fetal hydronephrosis. Br J Obstet Gynaecol 1998;105:860–4.[Medline]
- Benacerraf BR, Mulliken JB. Fetal cleft lip and palate: sonographic diagnosis and postnatal outcome. Plastic Reconstr Surg 1993;92:1045–51.[Medline]
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Abstract
Introduction
