X-linked Malformation and Cochlear Implantation.

OBJECTIVE: To evaluate if cochlear implantation is safe and constitutes an option for hearing rehabilitation of children with x-linked inner ear malformation. STUDY DESIGN: Retrospective patient review in combination with a multidisciplinary follow-up. SETTING: Tertiary referral hospital and cochlear implant program. PATIENTS: Ten children with severe-profound mixed hearing loss and radiological findings consistent with Incomplete Partition type 3 cochlear malformation received cochlear implants during the years 2007 to 2015. Nine of the children had a mutation affecting the gene POU3F4 on Xq21. INTERVENTION: Cochlear implantation. MAIN OUTCOME MEASURES: Surgical events, intraoperative measures and electrical stimulation levels, hearing and spoken language abilities. RESULTS: In all, 15 cochlear implantations were performed. In three cases the electrode was found to be in the internal auditory canal on intraoperative x-ray and repositioned successfully. One child had a postoperative rhinorrhea confirmed to be cerebrospinal fluid but this resolved on conservative treatment. No severe complications occurred. Postoperative electrical stimulation levels were higher in 9 of 10 children, as compared with typically reported average levels in patients with a normal cochlea. Eight patients developed spoken language to various degrees while two were still at precommunication level. However, speech recognition scores were lower than average pediatric cases. CONCLUSION: Cochlear implantation is a safe procedure for children with severe-profound mixed hearing loss related to POU3F4 mutation inner ear malformation. The children develop hearing and spoken language but outcome is below average for pediatric CI recipients.

Do extant elephants have superior canal dehiscence syndrome?

CONCLUSION: X-ray CT of an Asian elephant's skull suggest that elephants do not have a labyrinthine 3(rd) mobile window. This excludes the concept that elephants benefit from enhancement of bone conducted vibration by an extra opening of the labyrinth. This finding does not, however, exclude that elephants use bone conducted hearing for seismic detection, nor that other species may use an extra labyrinthine opening for improved detection of seismic signals. OBJECTIVES: In man, a pathologic extra opening of the bony labyrinth causes altered hearing with supranormal bone conduction. Theoretically, this variation in auditory performance could be advantageous for detection of seismic waves. METHOD: The skull of an adult Asian elephant was examined by X-ray computed tomography to investigate whether a natural '3(rd) mobile window' mechanism for enhanced sensitivity of body sounds exist in elephants. RESULTS: Although the entire elephant's skull was otherwise broadly aerated, the labyrinth areas were surrounded by dense bone.

Evaluation of the effective dose of cone beam computed tomography and multi-slice computed tomography for temporomandibular joint examinations at optimized exposure levels.

OBJECTIVES: To compare the effective dose to patients from temporomandibular joint examinations using a dental cone-beam CT device and a multi-slice CT device, both before and after dose optimization. METHODS: A Promax3D (Planmeca, Helsinki, Finland) dental cone-beam CT and a Lightspeed VCT (GE, Fairfield, USA) multi-slice CT were used. Organ doses and effective doses were estimated from thermoluminescent dosimeters at 61 positions inside an anthropomorphic phantom at the exposure settings in clinical use. Optimized exposure protocols were obtained through an optimization study using a dry skull phantom, where four observers rated image quality taken at different exposure levels. The optimal exposure level was obtained when all included criteria were rated as acceptable or better by all observers. RESULTS: The effective dose from a bilateral examination was 184 µSv for Promax3D and 113 µSv for Lightspeed VCT before optimization. Post optimization the bilateral effective dose was 92 µSv for Promax3D and 124 µSv for Lightspeed VCT. CONCLUSIONS: At optimized exposure levels, the effective dose from cone-beam CT was comparable to MSCT.

Ménière's disease in children aged 4-7 years.

This is a retrospective review of clinical data and audiovestibular test results from four children in whom symptoms suggesting Ménière's disease started at 4-7 years of age. The four patients all had spontaneous recurrent attacks of (spinning) vertigo and fluctuating low frequency sensorineural hearing loss from an early age, suggesting a diagnosis of definite Ménière's disease. Presumably, due to age-related inability to communicate auditory symptoms, the children did not initially meet requirements for a diagnosis of Ménière's disease. However, by 8 years of age, all four children reported tinnitus and/or fullness in the affected ear and, thus, met the AAO criteria for Ménière's disease. Even if information on subjective auditory symptoms is missing, it is reasonable to consider young children with idiopathic spontaneous recurrent attacks of vertigo in whom audiograms reveals fluctuating low frequency hearing loss to have Ménière's disease. This report is a reminder that Ménière's disease may also occur in young children.

Incisor root resorption due to ectopic maxillary canines: a long-term radiographic follow-up.

OBJECTIVE: To document the long-term fate of maxillary incisors with resorbed roots after correction of the associated ectopic canines. MATERIALS AND METHODS: The subjects were recruited from 107 children and adolescents age 9-15 years (mean 12.5 years) at initial registration, with 156 ectopically positioned maxillary canines. The children were referred to the specialist orthodontic clinic for consultation because of the risk of incisor root resorption. Of 51 patients contacted, 16 failed to attend. Eight of the remaining 35 were excluded because their lateral incisors had been extracted, leaving 27 subjects for follow-up registration. At initial consultation, all subjects had undergone radiographic examination, including computed tomography (CT) scans. At the follow-up consultation, the radiographic examination was limited to intraoral films. RESULTS: No resorbed incisor was lost during the 2- to 10-year follow-up period. The resorptive lesions had undergone repair in 13 teeth, remained unchanged in 12 teeth and progressed in 7 teeth. In the 13 teeth exhibiting signs of repair, no resorption was detectable in 11 teeth and minor resorption was detected in 2 lateral incisors. At the initial registration, severe or moderate resorption had been diagnosed in 12 lateral and 5 central incisors, compared with 11 lateral and 6 central incisors at follow-up. In 10 subjects initially diagnosed with resorption of 13 incisors, the lesions were no longer discernible on intraoral radiographs at follow-up. CONCLUSIONS: Even in cases of severe resorption, the incisor roots show good long-term healing. Incisors with root resorption can be used in an orthodontic appliance system.

FGF10 missense mutations in aplasia of lacrimal and salivary glands (ALSG).

Aplasia of lacrimal and salivary glands (ALSG) is an autosomal dominant congenital anomaly characterized by aplasia, atresia or hypoplasia of the lacrimal and salivary systems. Affected individuals present with irritable eyes and dryness of the mouth with variable expressivity. Mutations in FGF10 were recently described in ALSG and in lacrimo-auriculo-dento-digital (LADD) syndrome which are overlapping clinical entities. We present here two families with ALSG associated with missense mutations (R80S and G138E, respectively) affecting highly conserved residues in FGF10. The clinical features of these patients further broaden the knowledge of FGF10-related phenotypes.

Mutations in the gene encoding fibroblast growth factor 10 are associated with aplasia of lacrimal and salivary glands.

Autosomal dominant aplasia of lacrimal and salivary glands (ALSG; OMIM 180920 and OMIM 103420) is a rare condition characterized by irritable eyes and dryness of the mouth. We mapped ALSG to 5p13.2-5q13.1, which coincides with the gene fibroblast growth factor 10 (FGF10). In two extended pedigrees, we identified heterozygous mutations in FGF10 in all individuals with ALSG. Fgf10(+/-) mice have a phenotype similar to ALSG, providing a model for this disorder. We suggest that haploinsufficiency for FGF10 during a crucial stage of development results in ALSG.

Long-term results of orthodontic treatment of impacted maxillary canines.

A total of 61 children who had 83 maxillary canines impacted were followed up for a mean of 3.5 years (range 1.1-10.9 years) after treatment to evaluate the long-term results of the treatments. In most of the children, the impacted maxillary canines had been surgically exposed and treated with fixed orthodontic appliances. In 11 cases, lateral incisors had been extracted because of extensive root resorption. The esthetic results as well as functional and periodontal conditions were evaluated. Only four of the 61 children were not satisfied with the esthetic result, whereas orthodontists judged only 56% of the results as esthetically acceptable on clinical evaluation and 57% as esthetically acceptable on color slides. The periodontal conditions and the occlusal function on sides with previously impacted canines and on sides with normally erupted canines, on the whole, were similar. Exceptions were pocket depths of the left lateral incisors and left canines, but these variables were significantly different mainly because of one patient. In lateral movements of the mandible, however, significant differences in contact pattern were found between sides with normally erupted canines and sides with impacted canines. Canine rise occurred more often on working sides with normally erupted canines than with impacted canines.

Does the canine dental follicle cause resorption of permanent incisor roots? A computed tomographic study of erupting maxillary canines.

We performed computed tomography (CT) on 107 children and adolescents aged 9-15 years with 176 unerupted maxillary canines (152 erupting ectopically and 24 erupting normally) to determine whether there is an association between widened dental follicles of the maxillary canines and resorption of the adjacent incisors during eruption. Contiguous axial (transverse) CT scans were obtained through the maxilla in the region of the canines. The width and shape of the dental follicles were recorded, as were any contacts between the follicles and the crowns of the maxillary canines and neighboring incisors. Fifty-eight lateral incisors (38%) and 14 central incisors (9%) had some type of root resorption. The position of the maxillary canine in relation to the root of the lateral incisor varied greatly, as did the width and shape of the canine dental follicle. Follicle width ranged from 0.5 mm to 7.0 mm. The mean +/- SD width of dental follicles was, on average, larger for the ectopically positioned canines (2.9 +/- 0.8 mm) than for the normally erupting canines (2.5 +/- 0.8 mm) (P < or = .01). We found that during eruption, the follicle of the erupting maxillary canine frequently resorbed the periodontal contours of adjacent permanent teeth but not the hard tissues of the roots. We concluded that the dental follicle did not cause root resorption of permanent teeth. Resorption of neighboring permanent teeth during maxillary canine eruption was most probably an effect of the physical contacts between the erupting canine and the adjacent tooth, active pressure during eruption, and cellular activities in the tissues at the contact points, all of which are part of the eruptive mechanism. The findings also confirm an association between root resorption of deciduous canines and the dental follicles of erupting permanent canines.