The three-dimensional reverse face (3D RF) view for the diagnosis of cleft palate.

Abstract

Orofacial clefting (CL/P) is among the most common of congenital abnormalities, with an incidence of nearly 2/1000 births1. Because they arise from different embryological tissues, clefts of the lip (CL) and primary palate i.e. the alveolus and palate to the incisive foramen (CLA) can occur independently of clefts of the secondary palate (CP) and vice versa. In Denmark isolated CP accounts for 25% of the total cases of CL/P but surveys in other countries show that this rate varies and it has been reported to be over 50% in some European countries2–4. CL and CLA can be lateral, bilateral and medial and are due to a variety of failures of fusion of the maxillary swelling with the medial nasal process. CP is always midline and is the result of failure of the palatine processes to elevate or grow. The prognosis for CLA is also very different from that of CP, which is significantly more associated with difficulties of speech, hearing and feeding and (following surgery) mid-face protrusion. The majority of cases are multifactorial so prenatal diagnosis will primarily depend on careful screening with ultrasound. The effectiveness of screening for CL/P by ultrasound varies widely between series. Stoll et al.5 described how a systematic approach improved the detection rate of facial clefts from about 5% between 1979 and 1988 to over 26% during the years 1989–1998. Nevertheless, the rate of diagnosis of isolated CP is extremely low6 as a palatal defect will not be recognized on the standard obliqueface view that is routinely used to assess the upper lip and alveolar ridge, because shadowing of the palate by the densely bony ridge makes visualization difficult. Even the introduction of 3D technology which has improved the detection of CLA7–9 does not appear to improve visualization of the secondary palate10. In this issue’s Picture of the Month we show an image of CP visualized using a new ultrasound technique, the three-dimensional (3D) reverse face (3D RF) view which overcomes problems of shadowing and is simple, rapid and appears to be effective in visualizing the palate and palatal defects. We have carried out investigations using this technique with the GE Voluson 730 ultrasound machine (GE Medical Systems, Bedford, UK) which has Figure 1 Ultrasound image of a normal fetus using the three-dimensional reverse face view: the nasal cavity is situated between and just below the symmetrically placed orbits, and the intact palate is seen as a distinct horizontal line separating the nasal and the oral cavities.