Congenital Malformations of the Ear

Inner ear malformations in patients with sensorineural hearing loss: detection with gradient-echo (3DFT-CISS) MRI

The sensitivity of different MRI sequences in the detection of inner ear malformations in patients presenting with sensorineural hearing loss (SNHL) and/or vertigo was evaluated. We studied 650 patients presenting with SNHL and/or vertigo, clinically not suspected of having inner ear malformations. The sensitivity of T1-weighted, Gd-enhanced T1-weighted and (when available) T2-weighted spin-echo images, and three-dimensional Fourier transformation-constructive interference in steady state (3DFT-CISS) gradient-echo images, to unexpected malformations was assessed. Inner ear malformations were found in 15 (2.3%) of these patients. Enlargement of the endolymphatic duct and sac was the most frequent malformation, found in 11 patients. The 3DFT-CISS images showed all lesions; the other sequences were less sensitive and the pathology was missed, partially or only retrospectively seen in 11 of the 15 patients. Therefore, in addition to the routine unenhanced and Gd-enhanced T1-weighted and T2-weighted images, thin gradient-echo (3DFT-CISS) images are necessary to detect all clinically unexpected inner ear malformations in patients presenting with vertigo and/or SNHL.

Neurologic findings in children with ear malformations

Cephalic neural crest cells contribute to the formation of the external and middle ears, the supporting cells of the statoacoustic ganglion, other cranial nerve components, and the face. The anlage of otic sensory structures receive inductive stimuli from adjacent rhombencephalic tissue. The complex series of interactions that guide organogenesis of the outer, middle, and inner ear structures may explain why neurologic dysfunction is likely to be associated with malformations of the ear. We reviewed the records of 100 patients with complex ear anomalies with or without hearing loss. Mean age was 4.2 years (range 1 day-27 years). Malformations, either bilateral (70) or unilateral (30), involved the external ear (94), middle ear (16), and/or inner ear (12). Eighty-five patients had neurologic dysfunction. Cranial nerve dysfunction was found in 56 patients and involved nerves VIII (39 auditory and/or vestibular), VII (22), II (11), VI (8), V (4), III (3), X (3), XII (1), and IX (1). Sixty-four patients had evidence of central nervous system dysfunction such as mental deficiency/developmental delay (44), non-paretic gait disorders (17), hypotonia (16), microcephaly (13), seizures (8), motor deficits (8), autistic features (7), and radiographically confirmed intracranial abnormalities (5). Eleven of 19 children with hypoactive vestibules had delayed motor development or poor balance. Seventy-four patients had anomalies in other organ systems: 56 craniofacial, 28 osseous, 19 cardiac, 16 genito-urinary, 14 ocular, 11 gastrointestinal, and 7 cutaneous. Sixty-one patients had syndromic conditions, 32 of them branchial arch syndromes. The level of cognitive competence was not related to severity of craniofacial, ear, or cranial nerve abnormality. Children with ear malformations deserve neurologic and pediatric evaluations in addition to an otologic work-up.