Computer-stimulated test fitting of an implantable hearing aid using implantable hearing aid using three-dimensional CT scans of the temporal bone: preliminary study

In preparation for future implantation of the implantable middle ear transducer in patients, a method was sought for preoperatively test fitting a model of the device, using computer generated three-dimensional (3-D) temporal bone images derived from spiral computed tomography (CT) data. A 3-D model of the implantable middle ear transducer was designed using NIH Image software on a Macintosh computer. High resolution human temporal bone CT scans were obtained using a spiral CT scanner (Siemens Somatom Plus S). The 3-D transducer model was superimposed onto 3-D reconstructions of the temporal bone using ANALYZE software on a computer graphics workstation (Sun SPARCstation 10), showing the transducer "implanted" in the temporal bone. Measurements were validated using a cadaver temporal bone. This process produced images demonstrating the "fit" of the current transducer design in the mastoid region of the adult temporal bone. It permitted assessment of the proximity of surrounding structures such as the external auditory meatus, dura, or sigmoid sinus. Preliminary cadaver validation measurements confirmed the accuracy of this method. Three-dimensional CT is a feasible method for preoperative planning of the surgical implantation of devices in the temporal bone. This method of 3-D test fitting will be used in the future to determine optimum orientation and size limitations for human implantable devices.     

Indications for middle ear obliteration within the scope of cochlear implant management

BACKGROUND: Cochlear implants have gained worldwide acceptance as a reliable method of rehabilitation of profoundly hearing-impaired patients. Due to thorough patient selection major postoperative complications rarely occur and are flap related in most cases. Deafness can develop during chronic suppurative otitis media, either coincidentally or secondary to the medical treatment; normally this condition is regarded as a contraindication for cochlear implantation. In cases with a mastoid cavity after surgical treatment for cholesteatoma, the electrode covered only by the epithelial lining will likely become exposed or extruded. Therefore we suggest the obliteration of the middle ear cleft with abdominal fat and the blindsac closure of the external ear canal before cochlear implantation in these conditions. PATIENTS: The average age of our 12 patients was 48 years, whereas the youngest was 2 1/2 years of age. Due to chronic inflammatory ear disease. 11 patients had a mastoid cavity on both ears. Eight patients had a cholesteatoma, the chronic bone destroying process in the temporal bone of two female patients was considered as a fibroinflammatory pseudotumor. The child had a congenital deafness in both ears with a Mondini dysplasia in CT scan. She had already developed two episodes of pneumococcal meningitis which was caused by a defect in the stapes footplate through which a liquor-filled cystic sac herniated in the middle ear. Because of a massive liquorrhoea after opening of the sac, we decided to obliterate the middle ear cleft after successful insertion of the electrode array. RESULTS: All active electrodes of 10 Nucleus implants (Cochlear) and two Clarion devices (Advanced Bionics Corp.) were successfully inserted in the cochlea of the 12 patients. After an average follow-up of 15 months, a temporary facial palsy in one patient and an insufficient closure of a retroauricular fistula over the mastoid cavity in two cases were observed as postoperative complications. One patient with a fibroinflammatory pseudotumor developed a massive inflammatory reaction in the implanted ear two months after cochlear implantation, which could not be controlled by conservative treatment. The implant had to be removed and local conditions settled after administration of immunosuppressive treatment with cyclophosphamide. The patient received a new implant seven months ago. CONCLUSIONS: Implantation of a foreign body in a potentially infected space which communicates intracranially means a surgical challenge which can be managed by obliteration of the middle ear after subtotal petrosectomy with abdominal wall fat combined with a reliable closure of the external ear canal. In case of massive inflammation we would prefer a two-stage procedure.     

5-year series of constricted (lop and cup) ear corrections: development of the mastoid hitch as an adjunctive technique

Despite the multitude of corrective procedures described, adequate surgical correction of the congenital constricted ear remains a challenge. The maintenance of the shape and elevation of the reconstructed upper neohelix poses a particular problem. In the present series, experiences with lop ear correction utilizing standard techniques and the use of the mastoid hitch as a useful adjunct to these procedures are described. A total of 19 ears were reconstructed. There were three type 1, eight type 2a, seven type 2b, and one type 3 deformities (Tanzer classification). A graded sequence of procedures was adopted. Mild deformities were corrected by cartilage scoring techniques; a V-Y advancement of the helical root was added for moderate deformities. Cartilage expansion by a banner flap was required for more severe deformities. A mastoid hitch, whereby the refashioned upper neohelix is sutured to the mastoid fascia, should be used as an adjunct to these procedures to maintain helical elevation and prevent recurrence. Severe type 3 deformities may require autologous auricular reconstruction. Mean follow-up time was 1 year. There were six excellent, seven good, four fair, and two poor results. Two patients who had not had mastoid hitch procedures developed a recurrence of the lop deformity. Adequate surgical correction of constricted ear deformities requires a variety of surgical techniques. The mastoid hitch being used for constricted ear correction has not been described elsewhere. The mastoid hitch is a useful adjunctive procedure that may be used effectively in combination with other procedures.     

Interaction between bile salts and beta-adrenoceptor antagonists

Chronic suppurative otitis media (CSOM) in profoundly deaf patients is a contraindication for cochlear implantation. Eight (6%) of the 126 patients referred to cochlear implantation at this center between 1986 and 1992 became deafened as a result of bilateral CSOM but were otherwise suitable candidates. This study details the methods used in four patients to prepare the septic ear for a sterile device. Two patients had wet radical cavities with residual cholesteatoma, and two had discharging safe perforations resistant to surgical repair. Obliteration of the middle ear cleft with blind pit closure of the ear canal was attempted in all four patients, and cochlear implants were installed at a second operation 3 to 6 months later. The hearing results were as good as in implanted patients without CSOM, and the only complication has been the finding of a cholesteatoma pearl at the second operation in one patient. Fat obliteration of the mastoid and middle ear with blind pit closure of the ear canal can be adapted to make most chronic ears fit for implantation, if the patient is prepared to undergo two operations.     

Replacement of ear ossicles with titanium prostheses

BACKGROUND: Titanium has been a well established implant material for many years. New material processing techniques now permit the manufacture of small implants for ossicular chain reconstruction. METHODS: Between November 1994 and September 1995, 100 titanium middle ear implants (55 PORP, 45 TORP) were used for reconstruction of the ossicular chain. A range of five different sizes for partial and total protheses suits all implantation needs. The shape of the implants can be altered by bending. Time consuming intraoperative shaping and trimming is avoided. RESULTS: At a follow-up time of three months (33 patients) and six months (17 patients), no adverse reactions or extrusions occurred. Biologic fixation between the foot of the partial prothesis and the head of the stapes was found eight months after implantation. A hearing result of 0-20 dB residual air-bone gap was achieved in 79%. CONCLUSION: Titanium middle ear implants show good bio-compatibility and are readily integrated into the ossicular chain. Although delicate in shape, they offer excellent mechanical properties in respect to sound conduction and implantation. Initial results show Titanium to be a perfect implant material for middle ear prostheses, although long-term results are not yet available.     

An implantable piezoelectric hearing aid transducer for inner ear deafness. II: Clinical implant]

A miniature, hermetically sealed implant was development and manufactured in several clinical and technical iteration steps based on the prototype of an implantable piezo-electric hearing-aid transducer described in Part 1 of the work presented here. The transducer is made of pure titanium (medical grade 2, ASTM F67) and designed to be implanted into the mastoid cavity. Transfer of mechanical oscillations to an ossicle in the middle ear is effected by a fixed directly coupling rod of pure titanium or via suitable coupling elements. The transducer is highly tuned with a resonance frequency in the range of 7-10 kHz, depending on the dynamic mass load. Below this resonance and down to low frequencies, the frequency response of elongation is smooth with a very small ripple of less than +/- 1 dB. Unlike the prototype, an increase in vibration amplitude of around 10 dB was achieved for a comparable power consumption. Vibration amplitude at low and middle frequencies is about 60 nm with a transducer voltage of 1 V, corresponding to an equivalent sound-pressure level of around 100 dB SPL at up to 1 kHz. At higher frequencies of up to 10 kHz, the output level increases to beyond 130 dB SPL. Nonlinear distortions at maximum volume (1 V) are extremely small (THD < 0.1%) throughout the whole transfer range. Due to an extremely short attack time (50 microseconds) and short release time (approximately 2 ms), the dynamic properties of the transducer allow good transmission of audio signals with fast changes in the time domain, i.e., plosives in speech signals. Electric power consumption at full volume and broadband signals is in the region of 1 microW. Unlike electromagnetic transducers described in the literature, the low power consumption of this piezoelectric transducer allows the realization of fully implantable hearing aids for rehabilitation of moderate to severe sensorineural hearing loss.     

Ocular impairments in an impairment survey of leprosy-affected persons in Nepal

To date, there is no satisfactory treatment for persistent eustachian tube blockage or negative pressure in the middle ear. Conventional ventilation tubes are usually either occluded or extruded with time. A new treatment of percutaneous mastoid vent provides permanent ventilation to the middle ear cleft without putting a tube through the eardrum. A titanium tube is inserted through the skin into the mastoid antrum using the established technique of osseo-integration and hence becomes truly permanent. It can also be connected to a CPAP machine to re-inflate a collapsed eardrum. Initial trials consist of six vents inserted and followed up for 6-16 months. There was no sign of extrusion or a foreign body reaction. However, an inner Teflon tube is essential to keep the vent patent for permanent ventilation to the middle ear cleft.     

The use of homograft stapes

Homograft stapes were used for ossicular reconstruction in 43 ears over a three-year period. The average hearing improvement was 7.9 db. These cases were divided into groups: those with an intact posterior canal wall and those with an open mastoid cavity. The latter group fared better, with an average improvement of 15 db. Fourteen of the 43 ears were subsequently re-explored. Satisfactory bony union between the homograft stapes and recipient footplate was found in eight cases, four cases showed poor bony union, and bony resorption of the homograft had occurred in two patiemise for reconstruction of the ear with a loss of the stapes arch, especially in the presence of an open mastoid cavity and thus a shallow middle ear.     

基于改进YOLACT实例分割网络的人耳关键生理曲线提取

在人耳形状聚类、3D人耳建模、个人定制耳机等相关工作中,获取人耳的一些关键生理曲线和关键点的准确位置非常重要。传统的边缘提取方法对光照和姿势变化非常敏感。本文提出了一种基于ResNeSt和筛选模板策略的改进YOLACT实例分割网络,分别从定位和分割两方面对原始YOLACT算法进行改进,通过标注人耳数据集,训练改进的YOLACT模型,并在预测阶段使用改进的筛选模板策略,可以准确地分割人耳的不同区域并提取关键的生理曲线。相较于其他方法,本文方法在测试图像集上显示出更好的分割精度,且对人耳姿态变化时具有一定的鲁棒性。      

The problem mastoid cavity: medical and surgical management

The patient with persistent foul drainage from a previously operated-on mastoid cavity has a serious problem that requires aggressive attention from the otologic surgeon. The ear must be carefully evaluated in the office. Careful cleaning of the cavity and effective application of medication will dry up many of these cavities. Revision surgery of the ear requires a systematic approach using all the techniques of modern otologic surgery. This means the use of a post-auricular incision and wide bone removal combined with bone removal combined with obliteration techniques and grafting of the middle ear. This approach was used in 29 ears in 27 patients. Rapid healing and a trouble-free, dry ear was obtained in 26 patients or 90% of the operated-on cases.     

Usefulness of ictal and interictal 99mTc ethyl cysteinate dimer single photon emission computed tomography in patients with refractory partial epilepsy

OBJECTIVE: The aim was to investigate the feasibility of recording the electrical auditory brain stem response (EABR) evoked by electrical stimulation at the promontory (Prom-EABR) as a tool to assist selection of the ear for cochlear implantation in young children. STUDY DESIGN: The study group consisted of young children for whom the decision to proceed with implantation with the Nucleus mini 22-channel cochlear implant (Cochlear (UK) Ltd., London, UK) had already been made. SETTING: The Prom-EABR was recorded after the children had been anesthetised, but before the start of surgery. PATIENTS: A group of 25 children (11 boys and 14 girls), whose age at implantation ranged from 2 years 11 months to 6 years 8 months (mean age, 4 years 5 months), were investigated. INTERVENTION: Recordings of the Prom-EABR were used to determine which ear would receive the cochlear implant, providing there were no preexisting contraindications regarding selection of the ear. MAIN OUTCOME MEASURE: It has been suggested from earlier studies that the characteristics of the amplitude input/output (I/O) function of the EABR are related to neuronal survival. If the ear with the "better" I/O function is chosen for implantation, it might be expected that these children will perform better on average than those in whom the ear has been selected at random. RESULTS: Reliable recordings of the Prom-EABR were achieved in 40 ears (80%) of the 50 ears in the study. In 20 of the 25 children the technique was actively employed for selection of the ear for implantation. CONCLUSIONS: Recording of the Prom-EABR in the operating theater is a viable technique. Future analysis of long-term outcome measures of performance with the implant will confirm or dispute the benefit of ear selection using the Prom-EABR.     

One year real world prospective follow-up study of a major depressive episode of patients treated with paroxetine and pindolol or paroxetine for 6 weeks

Among cochlear implant candidates there are patients who have abnormal middle and/or inner-ear conditions that make them unsuitable for implantation. Insertion of a foreign body may also be contraindicated in the setting of an existing or potential intracranial communication, or when the ear is prone to infection. Five patients presented with such unfavorable conditions. These included a Mondini dysplasia with persistent cerebrospinal fluid leak, an atretic mastoid with meningocele, chronic otitis media, a transverse petrous bone fracture, and a temporal bone adenoma. All patients underwent subtotal petrosectomies and cochlear implantations. In four cases implantation was performed concomitantly with subtotal petrosectomy, while the remaining case required a two-stage procedure. No complications occurred. The technique is described in detail, and the cases and the indications for surgery are discussed. By obliterating and isolating the tympanomastoid cleft from the outer environment and utilizing the technique of subtotal petrosectomy, a broader spectrum of patients can now be implanted safely.     

Transient leukaemia cutis in chronic lymphocytic leukaemia

The sequelae of secretory otitis media (SOM) were monitored in 72 adult patients with SOM who were followed up for an average of 33 months. It was found that SOM became chronic and retraction of the tympanic membrane appeared as a function of the pneumatization of the mastoid. Ears with poor pneumatization (less than 6 cm2) developed chronic SOM in 52.2% of cases, as compared with 20% in cases with well-pneumatized ears (6 cm2 and above). Atelectasis developed in 37.3% of poorly pneumatized ears, and in only 5.7% of well-pneumatized ears. These sequelae may therefore be linked pathogenetically to the extent of pneumatization, as both the SOM and the sequelae appeared many years after formation and maturation of the pneumatic system. This study supports other studies that view the mastoid pneumatic system as an organ, as a middle ear pressure buffer. Well-pneumatized ears rarely develop a negative pressure and are seldom associated with chronic sequelae. Ears with poorly pneumatized mastoids lack the physiological function of such a pressure buffer. Ears with a tendency to develop a negative gas balance, whether as a result of deficient ventilation or excessive diffusion, will therefore develop a negative pressure more readily when their pneumatic system is underdeveloped, and consequently will be more prone to develop chronic sequelae.     

Gas exchange function of the middle ear in patients with otitis media with effusion

Gas exchange function through the middle ear mucosa was assessed using nitrous oxide (N2O) in patients with otitis media with effusion (OME), as well as in normal ears during elective surgery for unrelated disorders. In all normal ears except one (n = 43), an increase in pressure was observed after N2O inhalation. In 42 of 84 ears with OME, a pressure increase was observed, but not in the remaining 42 ears (50%), indicating that the gas exchange function in these latter ears was impaired. In 21 of the 42 ears showing no middle ear pressure increase following N2O inhalation, the middle ear pressure was again monitored after myringotomy and aspiration of the effusion A pressure increase was found in 16 ears, indicating that the impairment in gas exchange function in ears with OME may be reversible in most cases. Computed tomography of the mastoid was examined preoperatively in 66 ears, with the presence or absence of a middle ear pressure change well correlated in 57 ears with the presence or absence of mastoid aeration.     

Isochronic mapping of the auditory brainstem response: normative results

Isochronic mapping involves recording multi-channel evoked potentials from scalp electrodes and plotting contours of peak latencies. In this study, auditory brainstem responses were recorded from 20 electrode sites for left, right and binaural stimulation of each ear of 10 male and 10 female, normally hearing, young adults. Analysis of the data showed that the stimulus parameters of intensity, polarity and rate had no significant effect on the maps. On monaural stimulation, wave V was recorded first at the contralateral mastoid and ipsilaterally frontally and last at the ipsilateral mastoid some 350, mu s later. Binaural stimulation gave a symmetrical map, with wave V recorded first frontally and last at the occiput. In contrast, wave III was recorded first ipsilaterally and frontally and last at the contralateral mastoid. Wave II was recorded first at the rear of the contralateral mastoid and last forward of the ipsilateral mastoid. Comparisons between these results and human physiological studies are in agreement for waves V and III but do not support the concept of the VIIth nerve alone as the generator for wave II. These results suggest that this technique is a potentially useful diagnostic tool and it is intended to evaluate it by testing patients with a range of sensory, peripheral-neural and central-neural pathologies.     

Management of the mastoid air cell system in chronic otitis media

The influence of the Mastoid Air Cell System in Chronic Otitis Media is subject to much speculation. Does a mastoidectomy influence the surgical results following chronic inflammatory ear surgery? An understanding of the pathology associated within the mastoid air cell system is necessary before a discussion of the need for a mastoidectomy can be presented. Most mastoid air cell systems are sclerotic in chronic otitis media patients. The report summarizes one author's experiences with the influence of mastoidectomy upon surgical reconstruction for chronic inflammatory diseases of the ear. Emphasis is directed toward the eustachian tube rather than the mastoid air cell system.     

Homograft tympanic membrane myringoplasty

During a six-year period, homograft tympanic membranes have been used successfully for myringoplasty or tympanoplasty in 85% of 175 cases. This percentage is not as high as might be expected with fascia, and the homografts have not been as dependable in the wet, draining ear. However, the results do show that the homograft is an acceptable grafting material. The eardrums are not suggested as substitutes for fascia, but should be available for difficult cases. Their use is indicated in large or total defects to restore the natural anatomical conical shape of the eardrum, particularly in congenital atresia. The prime indication for their use is a missing malleus, and the malleus handle can be included within the transplant. The eardrum's rigid properties and the possibility of inclusion of ossicles make the homografts valuable in reconstruction of the old mastoid cavity.     

Influence of the gas exchange function through the middle ear mucosa on the development of sniff-induced middle ear diseases

To investigate the influence of gas exchange function through the middle ear mucosa on the development of sniff-induced middle ear diseases, the authors examined the mastoid pneumatization among patients with sniffing habit using computed tomography, and also examined the change of negative middle ear pressure induced by sniffing using tympanogram. In 20 ears with cholesteatoma or adhesive otitis media, the areas of mastoid cavity measured at the level of the lateral semicircular canal were significantly smaller than those in 26 ears with otitis media with effusion (OME) or attic retraction and in eight normal ears with sniffing habit (P < .01 and P < .0001, respectively). In 26 ears with OME or attic retraction, the areas of mastoid cavity were significantly smaller than those in eight normal ears with sniffing habit (P < .0001). By contrast, in the four ears with sniff-induced middle ear disease, the recovery of negative middle ear pressure in 5 minutes without swallowing was less than 10 mm H2O, whereas in all seven ears with normal eardrum, negative middle ear pressure recovered by more than 20 mm H2O in 5 minutes. These findings suggested that impairment of gas exchange function through the middle ear mucosa, as well as eustachian tube dysfunction, might be closely related to the development of sniff-induced middle ear diseases.     

Significance of a diastolic notch in the uterine artery flow velocity waveform induced by uterine embolisation in the pregnant ewe

OBJECTIVE: To determine whether water exposure causes middle ear contamination in patients with collar button tympanostomy tubes (TTs). METHOD AND DESIGN: An in vitro model of a human head that contained an auricle, external auditory canal, tympanic membrane with TT, middle ear, eustachian tube, and mastoid cavity was developed. Two electrodes connected to an external ohmmeter resided in the middle ear to detect water entry. The model was tested with 4 types of water exposure: showering, bathing, hair rinsing, and swimming. Statistical analysis was performed by the Fisher exact test. MAIN OUTCOME MEASURES: A positive test result corresponded to water entering the middle ear via the TT, confirmed by a resistance reading of zero on the ohmmeter. A negative test result indicated no change in the initial high resistance reading. RESULTS: No positive test results were obtained for showering (0 of 60 tests), hair rinsing (0 of 60 tests), or head submersion (12.7 cm) in clean tap water (0 of 60 tests). Ten positive test results were obtained for head submersion in soapy water (10 of 97 tests), which was statistically different from clean water (P< or =.007). Swimming pool depths of 30, 45, 60, and 75 cm elicited positive test results in 2 of 16, 3 of 18, 2 of 20, and 11 of 20 tests, respectively. A higher incidence of water entry into the middle ear occurred at depths of more than 60 cm (P< or =.001). No statistical difference between depths of 60 cm or less occurred (P= .88). CONCLUSIONS: Showering, hair rinsing, and head submersion in clean tap water do not promote water entry into the middle ear. Submersion in soapy water increases the probability of water contamination. Pool water infrequently enters the middle ear with head submersion, but the incidence increases with deeper swimming (>60 cm). These data provide further evidence that many water precautions frequently advised in patients with TTs are unnecessary.     

Drill-generated noise levels in ear surgery

The noise levels in the cochlea when a drill is used in the mastoid process have been calculated from vibration measurements on intact skulls of human cadavers and temporal bones. The results lend support to the conclusion that, in ear surgery the ipsilateral cochlea is exposed to noise levels of about 100 dB and the contralateral cochlea to levels 5-10 dB lower every time the drill is used. This noise trauma may account for some of the high-tone sensorineural hearing losses after tympanoplasty described by other authors.