Pediatric unilateral isolated choanal atresia is not associated with mandibular condyle hypoplasia.

PURPOSE: We hypothesized that the ontogeny of unilateral isolated choanal atresia involves a field defect manifesting as ipsilateral mandibular condylar hypoplasia. The topic is important because the mechanism of the unilateral isolated choanal atresia is unknown. MATERIALS AND METHODS: Retrospective self-controlled case series. We included 20 patients (2 males and 18 females, ages 2 weeks to 13 years) with unilateral isolated non-syndromic choanal atresia. We studied their high-resolution computed tomographic scans. Two otolaryngologists measured the largest cross-sectional area of the mandibular condyle in the axial plane perpendicular to the posterior border of each mandibular ramus independently. Statistical significance and inter-rater agreement were calculated with paired Wilcoxon rank sum test and Spearman's non-parametric correlation coefficient respectively. RESULTS: Cross-sectional areas of the condyles ipsilateral to the choanal atresia were not statistically different than those of the contralateral condyle (P = 0.27). Inter-observer agreement of condyle areas was excellent: Spearman's r = 0.85 on the right and r = 0.94 on the left. CONCLUSIONS: In this cohort of children with the rarity of isolated non-syndromic unilateral congenital choanal atresia, no associated mandibular condyle hypoplasia was found. The data suggest that the underlying ontogeny was unlikely attributable to a field defect.

Angles of Axes of Incudes.

Incus angles of axes (the angle between "short process axis" and the "long process axis") are more open in humans than chimpanzees: 64.0 versus 55.7 degrees (Quam et al.: J Anat 225 (2014) 167-196). However, Flohr et al. (Anat Rec 293 (2010) 2094-2106) raise concern about interobserver agreement of the axes. The concern is important as phylogenetic relationships of mammals are inferred from the incus (and malleus and stapes). We sought to check (1) interobserver agreement; and (2) if the angles of the axes of incudes (incuses) exhibit bilateral symmetry, which is expected if the axes are genetically determined. We studied incudes from 41 modern adult crania with clinically normal temporal bones. Angles of axes were determined on rectilinear digital photographs of incudes in standard lateral orientation. Two observers independently drew the axes and measured the axes. Interobserver agreement was within 4 degrees for 24 of 34 left-sided incudes and for 27 of 35 right-sided incudes. The mean of the two observers' angle determinations were used. Left incudes' median was 67 degrees, range 60-73; right 67.5 degrees, range 58-77. Bilateral symmetry of angles of axes was found: r = 0.55, N = 31, 95% CI 0.24-0.75. Angles of axes of modern human incudes are probably genetically determined features, but are of doubtful physiologic or evolutionary advantage in modern humans. Interobserver agreement of angles of modern human axes is concerning and must be specified in reports. Consideration should be given to a convention to designate axes in ambiguous cases. Anat Rec, 302:1615-1619, 2019. © 2019 American Association for Anatomy.

Microcomputed tomography of the stapes: Wide-ranging dimensions.

Although human stapes are known to have varied dimensions and the footplate is considered to be oval (fitting as it does into the oval window), few studies of high-resolution imaging of these structures have been performed. No study appears to have addressed the bilateral symmetry of stapes dimensions or to have determined if an association exists between the size of the stapes and the size of mastoid pneumatization; a small mastoid pneumatization is an indicator of childhood otitis media. We obtained 41 ear-normal cadaver crania specimens for study in our temporal bone laboratory and isolated 10 for further analysis: the 5 with the largest areas of mastoid pneumatization and the 5 with the smallest. Microcomputed tomography of tissue blocks was performed on the in situ stapes. Using ImageJ software, we created a three-dimensional model of each stapes. The mean height of these stapes was 3.43 mm (range: 3.20 to 3.80), the mean length of the footplates was 2.71 mm (range: 2.52 to 2.97), and the mean width of the footplates was 1.23 mm (range: 1.12 to 1.46). Qualitatively, the footplate was shaped like a human footprint in moist sand, as Eysell described in 1870. The dimensions of the stapes were found to be bilaterally symmetrical in general, but there was no correlation between these dimensions and the size of mastoid pneumatization. The distribution of footplate widths may be bimodal, which is consistent with the observation of Sim et al that men have wider footplates than do women.

Spatial orientation of the adult cochlea: rotation, tilt, and angle theta 3.

OBJECTIVE: Quantitative description in adult crania of (1) angular orientation of the basal turn of the cochlea relative to the sagittal (termed "rotation") and Frankfort horizontal (termed "tilt") planes, and angle theta 3 [angular relationship of the line defined by the cochlea's spiral center and cochlear (round) window, to the cochlear window]; (2) orientation of the cochlea relative to the plane defined by the horizontal and vertical portions of the facial nerve; (3) orientation of the basal turn of the cochlea relative to the plane of the posterior semicircular canal; and (4) the association of these orientations with the extent of mastoid pneumatization. METHODS: Postmortem material analysis. From 41 bequeathed anatomical ear-normal cadaveric cranial, high-resolution CT scans were performed of the five crania with the largest and the five with the smallest mastoids. Eleven points in three-dimensional Cartesian space were appointed and studied with the software program FIJI. RESULTS: The median angle values (and ranges) for right ears were: "rotation" 52° (range 47-61); and, "tilt" 84° (79-89). The planes of the cochlear basal turn and facial nerve approximated superimposition: median 15° (2-19). Angle theta 3 for right ears was median 40° (28-44). Bilateral symmetry was found for the relationships between the planes. However, no association of any planar relationship with mastoid pneumatization was suggested. CONCLUSION: Considering the range of angles found in clinically normal adult specimens, spatial orientation of the cochlea may explain some of the difficulties in implantation.

'Cochlear view' plain radiograph: A simple reliable positioning method.

INTRODUCTION: The plain 'cochlear view' radiograph for checking cochlear implant electrode coiling and depth of insertion is strongly influenced by positioning. The best accuracy and inter-observer agreement are achieved with the X-ray beam passing through the axis of the modiolus, which is perpendicular to the plane of the basal turn of the cochlea. The basal turn of the cochlea generally is 45 from the head's sagittal plane. OBJECTIVE: To describe a simple reliable technique of patient positioning to maximize the accuracy of postoperative radiographs in the evaluation of cochlear electrode insertion. METHODS: This is a description of patient positioning and radiographic technique for intra-operatively checking the position of the electrode array of a cochlear implant. For the surgery, the patient's head is rolled 60° to the side, and the head stabilized in/on a Mayfield horseshoe headrest. For the X-ray, the operating table is rolled 15° toward the operated ear. The central X-ray beam from the C-arm is directed from near the floor toward the ceiling, aiming for a mark 2 cm anterior to the external auditory meatus. DISCUSSION: Several plain radiograph views have been described to assess cochlear implant electrode array coiling in the cochlea and the depth of insertion of the electrodes. Images away from the 'cochlear view' not only are difficult to interpret but also falsely suggest malposition of the electrode array. The 'cochlear view' radiograph most accurately assessed the depth of insertion. CONCLUSION: This technique of getting the 'cochlear view' is simple and reliable.

Pain-only complaint about cochlear implant device: A five-patient pediatric experience.

OBJECTIVES: To present the case histories and management of five pediatric patients who experienced pain at the receiver-stimulator site, but no other indication that the device was failing. Patients were from a sole-surgeon pediatric practice (600 + implant surgeries before June 2013; about even proportions of Advanced Bionics, Cochlear Corporation, and MED-EL devices). METHODS: The University Institutional Review Board-approved review of sole-surgeon pediatric case series. RESULTS: The onset of pain ranged from 2 to 16 years post implantation. Pain, not amenable to conventional medical therapy, was present regardless of whether or not the external appliance was 'on', or even being worn on the head. Four of the five patients were bilaterally implanted, but pain was only at one receiver-stimulator package. Clinical management ultimately included revision surgery in all five cases, with immediate resolution of the pain in four. For those four, the replacement cochlear implant (CI) performed well; the other patient fears pain if her replacement device is used, but continues enjoying her contralateral implant. At analysis by the company, two of five explanted devices exhibited problems: loss of hermeticity; insulation failure. DISCUSSION: Though infrequently reported, pain-only complaint by a CI user is a challenging dilemma. CONCLUSION: Pain may be the sole clinical manifestation of cochlear implant device failure. We offer a flowchart for the care of CI patients with pain, encourage a worldwide registry of such cases, and offer ideas to try to understand better the problem.

Site for bone-anchored hearing system for children younger than 5 years.

OBJECTIVE: To describe in children younger than the present US FDA-approved 5 years of age the thickest part of the temporal bone available for placement of a bone-anchored hearing system. Children with unilateral hearing loss, as with aural atresia, have deficits in at least language comprehension and oral expression. The early provision of hearing to the atretic ear may minimize the potential for auditory deprivation. STUDY DESIGN: Point prevalence descriptive study. SETTING: Tertiary referral pediatric hospital. SUBJECTS AND METHODS: Thirty-eight patients less than 6 years old with congenital aural atresia had undergone temporal bone computed tomography (CT). Bone thickness lateral (ie, superficial) to the sinodural angle, in the topmost axial CT slice that included any adjacent petrous ridge, was measured. RESULTS: The mean bone thicknesses lateral to the sinodural angles of the atretic ears were 5.1, 5.0, 5.9, 5.2, 5.2, and 4.8 mm for the <1, 1-, 2-, 3-, 4-, 5-year-olds, respectively; of the non-atretic ears, thicknesses were 4.1, 4.9, 5.5, 6.7, 4.3, and 4.7 mm. CONCLUSION: Based on this small case series, bone thickness lateral (ie, superficial) to the sinodural angle is sufficient for many children suffering from aural atresia to have bone-anchored hearing devices implanted younger than age 5 years. Use of the sinodural site would require a magnetic bone-anchored hearing system, which could be repositioned posteriorly at age 5 years when pinna construction and atresiaplasty endeavors typically begin.

Morphologic variations of clinically normal mallei and incudes.

OBJECTIVES: Various features and shapes of malleus and incus are reported. Partially or unaddressed are their bilateral symmetry, correlation with otitis media, and concordance of features and shapes. Such information may contribute to the understanding of malleus and incus ontogeny and the installation and function of implantable middle ear devices. We sought to address the following hypotheses: (1) a cranium's malleus and incus have bilateral symmetry, with respect to their features and shapes; (2) features and shapes of malleus and incus are unrelated to the mastoid size indicator of childhood otitis media; and (3) an ear's malleus and incus have concordant features and shapes (ie, the presence or absence of a feature or shape of a malleus or incus is associated with the presence or absence of another feature or shape in that ear's malleus or incus). METHODS: Postmortem material-analysis prevalence study of 41 adult crania without clinical otitis media. Mastoid sizes were assessed radiographically. RESULTS: Most mallei had lateral processes and inflected manubrium tips. Most incudes had concave superior borders of their short processes, non-notched inferior borders of their short processes, and anteriorly curved anterior edges of their long processes. Only I feature, absence of the lateral process of the malleus, was suggested to have a relationship to small mastoid size. Concordance was not found for any shape or feature of the malleus or incus. CONCLUSION: Clinically normal mallei and incudes have feature and shape variations that are mostly bilaterally symmetric.

The foreshortened malleus: Anatomic variant, not pathologic sign.

OBJECTIVE: To quantitatively study the appearance of the malleus as viewed through the external ear canal clinically to determine whether its shortened appearance in some ears is associated with otitis media. STUDY DESIGN: Postmortem material analysis. SETTING: University temporal bone laboratory. SUBJECTS AND METHODS: A total of 41 adult crania without clinical otitis. The mastoid size indicator of previous childhood otitis media was quantified radiographically. On digitized photographs of the tympanic membranes (64 ears useable), two sets of measurements were performed: 1) the distance from the malleus' lateral process to the umbo and to the annulus; and 2) angles formed anteriorly and posteriorly at the umbo. RESULTS: The two metrics of malleus foreshortening did not correlate with one another, that is, the ratio manubrium-length/tympanic diameter did not correlate with the ratio posterior/anterior umbo angles (for right ears, r = -0.34; for left, r = 0.30). Mastoid size did not correlate with either metric of malleus foreshortening. As to right-left symmetry, the size of mastoid pneumatization had good correlation (r = 0.68, 95% confidence interval 0.47-0.82); but, r = 0.21 for lengths, r = 0.34 for angles, each confidence interval included zero. CONCLUSION: Because the data showed no correlation of the physical appearance of the malleus with the mastoid size indicator of otitis media, and right-left symmetry was only hinted, we contend that a foreshortened malleus lacks clinical relevance. Foreshortened malleus is an anatomic variant, not a sign of pathology.

Transtympanic electrode positioning: manubrium is a poor guide.

BACKGROUND: Although a transtympanic electrode is commonly used for electrocochleography and electrically evoked auditory brainstem response, the variability of responses among healthy subjects is wide. The manubrium is the typical guidepost for electrode placement. This study addresses the hypothesis that electrode position relative to the round window niche is widely variable. STUDY DESIGN: : Postmortem anatomic dissection of 41 bequeathed adult crania (82 temporal bones). METHODS: Drill marks were made on the medial wall of the mesotympanum from 2 manubrium-based positions: 1.5 to 2 mm posterior to the umbo, and halfway between the umbo and the annulus posteroinferior. RESULTS: Distances to the lip of the round window niche ranged from 0.8 to 3.5 mm and from 1.8 to 4.5 mm for the 2 electrode sites, respectively. The posteriorly determined site was uniform on the promontory, but the posteroinferior site was into hypotympanic trabeculations in 81% of ears and into the jugular plate in 6%. Distances from the electrode sites to round window niche were not obviously associated with either the orientation of the manubrium in the head or the mastoid size. CONCLUSION: The location of a transtympanic positioned electrode using the manubrium as guidepost is not accurately predictable relative to the round window niche.