Diagnostic ultrasound ( PDFDrive )

CHAPTER 33 The Fetal Face and Neck 1151
standards before they are proicient in sonographic nasal bone
evaluation. 56
Other Nasal Abnormalities
Fetal nasal masses are rare but can be identiied with ultrasound.
Diferential considerations include glioma, dermoid, hemangioma,
and encephalocele. Fetal MRI is oten helpful in assessing for
intracranial extension, which is seen with encephalocele and
may be present with nasal gliomas. Nasal gliomas are composed
of heterotopic neuroglial tissue, usually located on the bridge or
side of the nose, and may be extranasal (60%), intranasal (30%),
or both (10%). 57-60 Nasal gliomas, in contrast to hemangiomas,
usually do not demonstrate signiicant vascular blood low on
Doppler. Dermoids are oten solid and cystic, heterogeneous
masses. Hemangiomas are frequently echogenic and demonstrate
vascular low on Doppler. Encephaloceles may contain only
meninges and cerebrospinal luid and thus appear cystic, or may
contain brain tissue and appear heterogeneous.
Frontonasal dysplasia is a rare anomaly 61,62 involving abnormalities
of the eyes, forehead, and nose and is deined by the
presence of two or more of the following: hypertelorism, skincovered
gap in the bones of the forehead (anterior cranium
biidum occultum), broad nasal root, median facial clet, nasal
ala clet, lack of formation of nasal tip, and V-shaped frontal
hairline (widow’s peak). 63
Cleft Lip and Palate
Worldwide incidence of clet lip, with or without clet palate, is
approximately 1 per 700 live births, 64 with an incidence in Caucasians
of approximately 1 per 1000 live births. he incidence of
facial cleting is lower in the African American population (0.3
per 1000), higher among Asians (2 per 1000), and highest in
Native Americans (3.6 per 1000 live births). It is more common
in males than females. 65 hese abnormalities usually result from
failure of fusion of the medial nasal prominences and maxillary
prominences. Although facial clets may occur as an isolated
inding, they are present with increased frequency in chromosomal
anomalies, including trisomies 13 and 18, and in other
structural anomalies, especially those involving the heart and
central nervous system. 66-68 Reports vary, with aneuploidy rates
of 5% to 30% in association with facial clets. 69-71 hus identiication
of a facial clet should prompt a detailed and complete evaluation
of the fetus for additional anomalies. Some isolated facial
clets are familial, with the recurrence risk dependent on number
of afected parents and siblings. 72
Reported accuracy in the sonographic detection of fetal clet
lip and palate ranges from 16% to 93%. 73-78 Robinson and colleagues
77 found that sonography performed ater 20 weeks’ gestation
had a signiicantly higher detection rate for clet lip than did
studies performed before 20 weeks, and they subsequently recommended
that fetuses at high risk for clet lip be evaluated ater 20
weeks’ gestation (Video 33.1, Video 33.2, Video 33.3). Using
state-of-the-art equipment, high-frequency probes, and endovaginal
sonography, detection is possible at earlier gestational
ages. Some question the eiciency and usefulness of 3-D sonography
in evaluating clets, 79 but many have found 3-D applications to
be extremely helpful. 8,80,81 Recent studies have described 3-D
techniques for evaluating the primary and secondary palate during
Differential Diagnosis of Cleft Lip and Palate
Teratogens
Diphenylhydantoin (phenytoin)
Valproic acid
Retinoic acid
Carbamazepine
Diazepam
Amniotic band syndrome
Holoprosencephaly
Ectodermal dysplasia
Frontonasal dysplasia
Robert syndrome
Miller syndrome
Trisomies 13, 18, and 21
Triploidy
the irst trimester. 82-84 Sommerlad and colleagues 85 found the 3-D
reverse face view could be obtained in 90% of patients at 20 to
34 weeks’ gestational age and correctly classiied clets of the lip,
alveolar ridge, and palate in nearly 90% of patients. However,
evaluation of the secondary palate remains challenging, even with
3-D lipped face techniques 86 and modiications 87 of this technique,
with adequate views obtained in just over a third of patients imaged.
Fetal facial clets should be described as completely as possible,
using standard craniofacial terminology and including accurate
description and classiication of the clet in relation to the lip,
nostril, alveolus (maxillary tooth bearing arc), and secondary
palate (Fig. 33.21). he secondary palate has an anterior, bony
segment and a posterior, sot tissue segment. Both clet lip and
clet palate may be unilateral or bilateral.
Information important to the surgeons for accurate parental
counseling, postnatal repair planning, and prognosis includes
whether the clet is unilateral or bilateral and complete or
incomplete (Fig. 33.22). A complete clet lip is deined as a clet
that fully divides the lip and extends completely through the
base of the ala of the nose and that usually is associated with a
clet of the underlying tooth-bearing alveolus as well. An incomplete
clet lip involves a portion of the lip, but at least a band
of sot tissue spans the clet. Incomplete clet lip does not involve
the ipsilateral underlying bony tooth-bearing alveolus (Fig. 33.23).
Associated sonographic signs of a clet palate include an
abnormally high position of the fetal tongue, hypertelorism,
deviation of the vomer (a triangular bone in the nasal septum
forming the posterior and inferior portion of the septum), and
micrognathia. 71,88,89 To describe the type of clet, two embryonic
structures are considered: (1) the primary palate, formed by the
prolabium, premaxilla, and columella, which includes the lip,
nares, and alveolus, and (2) the secondary palate, which begins
at the incisive foramen and is formed by a horizontal portion
of the maxilla, the horizontal portion of the palatine bones, and
the sot palate.
Clet palate may interfere with fetal swallowing and result in
polyhydramnios. Infants with clet palate have diiculty with
feeding, are at increased risk of otitis media, and may have
diiculty with hearing and speech. 65