Anomalies of the ear in the Pierre Robin triad.

Objectives: The Pierre Robin triad (PRT) consists of micrognathia-retrognathia, glossoptosis, and an oval or cleft palate. The goal of this study was to identify patterns of similarity to and differences from the two previous temporal bone studies of the PRT.

Methods: Seven children with the PRT (ages, 45 minutes to 2 years; gestational ages, 41 to 43 weeks) were studied. Thirteen temporal bones were decalcified, sectioned at a thickness of 20 microm, and studied by light microscopy.

Results: Our study demonstrated multiple architectural anomalies involving the entire ear, including abnormal auricles, and anomalies of the ossicles, including abnormal stapes footplates (6/13). All children showed signs of middle ear infection (12/13). Anomalies of the inner ear included aplasia of the lateral semicircular canals (5/13), a large vestibular aqueduct (2/13), and unusually large otoconia (1/13). In the mastoid process there were islands of cartilage in the expected position of Reichert's cartilage (9/13) and dehiscence of the fallopian canal (11/13). Loss of cochlear hair cells was seen in children who had antemortem hypoxia.

Conclusions: Although the PRT is caused by various genes, most anomalies can be traced to the development of the first and second branchial arches.