Aural Cartilage Research Articles

Development of monaural and binaural behind-the-ear cartilage conduction hearing aids

Hosoi (2004) found a pathway for clear sound transmission via aural cartilage. Our research group is developing a new hearing aid using this mechanism. The cartilage conduction hearing aid can be used in patients who cannot insert the earplugs of conventional hearing aids. The cartilage conduction hearing aid (model HD-GX) is composed of a main unit, a transducer, and a fitting part. The ring-shaped fitting part is placed in the entrance of the ear canal, and the vibration at the cartilage then generates sound in the external auditory canal. The cartilage conduction sound remains in the canal and reduces the risk of acoustical feedback. Considering this advantage, we designed it to wear behind the ear (BTE) (model HD-GX2). As binaural cartilage conduction can present sound directivity equivalent to that of air conduction, we then developed a binaural cartilage conduction hearing aid (model HD-GX3) by combining two BTE hearing aids.

Comparison of different autografts for aural cartilage in aesthetic rhinoplasty: is the tragal cartilage graft a viable alternative?

Auricular cartilage is an important source of grafts for various reconstructive procedures such as aesthetic rhinoplasty. The purpose of this investigation was to compare tragal cartilage with auricular cartilage harvested from the concha and scapha, and describe its clinical viability, indications, and morbidity in rhinoplasty. A total of 150 augmentation rhinoplasties with a total of 170 grafts were included. The donor sites were tragus (n=136), concha (n=26), and scapha (n=8). The time needed to harvest the grafts, the donor site morbidity, and the indications for operation were recorded. The anthropometric changes to 4 auricular variables after the cartilage had been harvested were analysed and compared with those on the opposite side in 48 patients using Student's paired t-test. Intraobserver reliability was assessed using Pearson's intraclass correlation. The mean (SD) harvesting time was 27 (8) min for the concha, 4.5 (1.4) min for the tragus, and 5.7 (1.6) min for the scapha. The largest graft was taken from the concha (28×19mm), followed by the tragus (20×12mm), and the scapha (18×6mm). The grafts were placed at the following sites: tip grafts (n=123), columella struts (n=80), shield (n=20), rim (n=17), and dorsal onlay (n=15). Harvesting tragal cartilage is safe, simple, fast, and has a low morbidity, but it can affect the patient's ability to wear earphones. Tragal cartilage is a good alternative for nasal reconstruction if a graft of no longer than 20mm is required.

Partial ear canal ablation and lateral bulla osteotomy in rabbits

Six lop rabbits were presented with clinical signs of otitis media or externa. The presence of disease was confirmed by computerized tomography examination, with two rabbits suffering from bilateral disease. The rabbits were anaesthetized and underwent surgery of the affected bulla. Rabbits with bilateral disease had a minimum of 2 weeks between procedures. A single vertical incision was made over the base of the vertical canal, which was bluntly dissected free from surrounding tissue. The ventral portion of the vertical canal was removed and a lateral bulla osteotomy was performed. The mucosa at the base of the dorsal vertical canal was apposed and the aural cartilage sutured to form a blind-ending pouch open at the pretragic incisure. Histopathological samples taken from the dorsal margin of the vertical canal yielded subtle and non-specific changes in the six samples submitted. All rabbits were discharged within 48 hours of surgery. The cosmetic outcome was excellent with animals retaining visually normal aural anatomy. The partial ear canal ablation/lateral bulla osteotomy procedure is quick and has a good cosmetic result when performed in rabbits.

Benefit of a new hearing device utilizing cartilage conduction

Our previous study demonstrated that sound was effectively transmitted by attaching a transducer to the aural cartilage even without fixation pressure. This new method for sound transmission was found by Hosoi in 2004, and was termed cartilage conduction (CC). CC can be utilized even in hearing-impaired patients who cannot use air-conduction hearing aids owing to continuous otorrhea or aural atresia. A prototype hearing aid employing CC was investigated in this study. Four patients with conditions such as continuous otorrhea and acquired aural atresia after surgery participated in this study. The CC hearing aid was fitted, and its benefits were assessed by audiometric tests and interview. Thresholds and speech recognition scores improved in all subjects. However, in subjects with continuous otorrhea, it was difficult to obtain the gains according to the target gains owing to their severe hearing loss and the limitation of the output level. On the other hand, unexpectedly large gains were obtained below 2kHz in the patient with acquired aural atresia. These large gains were probably caused by soft tissue filling the postoperative space. No subjects complained of pain associated with the attachment of the transducer, although such problems are usually observed for a bone-conduction (BC) hearing aid. This feature is considered one of the advantages of the CC hearing aid. The results of the audiometric tests and interview suggest that the CC hearing aid has potential as a useful amplification device for hearing disability. Unfortunately, if the soft tissue pathway is not involved, the current device is insufficient for the patients with severe hearing loss. The improvement of the output level will lead to develop a reliable CC hearing aid as an alternative to BC hearing aids or bone anchored hearing aids.

A cure for ear ACHES?!

Anyone who suffers from ear Aural Cartilage Hyper Extension Syndrome (ear ACHES) will appreciate these headphones. Ear buds aren't for everyone. It's not just about sound quality, but a reluctance to have ears stretched beyond the so-called ‘Dumbo-point’ by unforgiving knobs of plastic.

Closure of septal perforations by means of 'external rhinoplasty'

Objective. Evaluation of the ‘external rhinoplasty’ approach as a technique in the closure of septal perforations. Materials and methods. Ten patients with a septal perforation were studied. The average largest diameter ( sd ) was 1.48 cm 2 (0.39), as measured by lateral radiography after spreading the margins of the perforation with radiographic contrast fluid. Submucosal tunnels were made using a midcolumellar incision that was lengthened with marginal incisions, and the perforation was filled with aural cartilage. The extramucosalseparation of the upper lateral cartilages from the nasal septum allows the creation of a considerable mucosal flap in the nasal vault. By means of this transposition flap, together with a posterior based flap, all perforations could be covered. Results. Closure of nine septal perforations was successfully accomplished. Although it became smaller, one perforation persisted. Conclusion. The ‘external rhinoplasty’ approach provides a superior operative field. This visualization allows the formation of larger flaps. These advantages are translated into a greater success rate.

耳介軟骨板を用いた鼓室形成術

耳介軟骨板を用いた鼓室形成術

外耳道狭窄を伴った中耳奇形に対する乳突腔の開放後再建術

We reported a 15-year-old male exhibiting middle ear malformation with meatal cholesteatoma who was treated by a transmastoid operation 5 years after a meatoplasty. He showed slight microtia, meatal stenosis of the cartilaginous portion, atresia plate, abnormally located facial nerve, hypoplasia of the tympanum, fusion of the malleus and incus, chorda tympani adjacent to the atresia plate, intact incudo-stapedial joint and marked improvement of mastoid aeration after meatoplasty.Reconstruction of the opened cavity with an aural cartilage plate (attico-antromastoid reconstruction) was effective not only to obtain normal hearing and ear canal structure, but also to preserve mastoid aeration.

Replacement of the pathological temporomandibular articular disc using autogenous cartilage of the external ear

The technique and results of replacement of the articular disc by autogenous aural cartilage are presented. Out of 7 patients operated with a follow-up longer than 6 months, 5 have markedly improved. The cartilage seems to remain vital. It is concluded that this procedure may be indicated in patients with dysfunction and/or apparent damage of the disc. However, it is difficult in some cases to base the indication on more than circumstantial evidence.

Perichondrial potential for cartilagenous regeneration.

This preliminay investigation was conducted in 2-month-old rabbits. The perichondirum was stripped away from the ear cartilage, and raised as a flap. A segment of the exposed cartilage was then removed and the perichondrial flap was sutured back over the created defect. The other ear served as a control, but there the resection of cartilage included the covering perichondrium. In the first group there was a progressive regeneration of cartilage originating from the perichondrium; in the control study, no new cartilage developed. The chondrogenic activity of the perichondrium of the aural cartilage is thus demonstrated and will be further verified in succeeding experiments.

On the adequancy of equivalent circuits for piezomagnetic transducers: Woollett, R.S. Vol 23, No 6 (December 1970) p351

Hosoi (2004) found a pathway for clear sound transmission via aural cartilage. Our research group is developing a new hearing aid using this mechanism. The cartilage conduction hearing aid can be used in patients who cannot insert the earplugs of conventional hearing aids. The cartilage conduction hearing aid (model HD-GX) is composed of a main unit, a transducer, and a fitting part. The ring-shaped fitting part is placed in the entrance of the ear canal, and the vibration at the cartilage then generates sound in the external auditory canal. The cartilage conduction sound remains in the canal and reduces the risk of acoustical feedback. Considering this advantage, we designed it to wear behind the ear (BTE) (model HD-GX2). As binaural cartilage conduction can present sound directivity equivalent to that of air conduction, we then developed a binaural cartilage conduction hearing aid (model HD-GX3) by combining two BTE hearing aids.

An operation for saddle nose

Most of the saddle deformities are due to trauma; less frequently, they may be a racial characteristic and in rare cases they follow chronic specific inflammatory diseases. The author considers the alternatives for surgical correction: 1. The small saddle requiring no graft 2. the saddle requiring little graft for which septal or aural cartilage will suffice and 3. more severe saddles requiring graft tissues taken from elsewhere. In a recent series using silastic, good results were obtained when the silastic was inserted via a mid-line vertical columella incision and not via an intra-nasal or intra-oral approach.