人工耳蜗植入术残余听力保留现状和研究进展

随着手术方法和电极设计等技术的创新,人工耳蜗手术取得了一定的进步,使患者残余听力得到一定的保留。所有手术方法的共同目标即是：保护耳蜗内结构,保留残余听力,以提高听觉言语能力。人工耳蜗术后残余听力的丧失被认为是多种因素的结果,近年来,为获得更好的残余听力保留,人们在电极设计与选择、新型电极涂层、围手术期药物治疗、机器人辅助、图像和电生理引导等方面的研究有了新的突破,对于残余听力的保护有了很大程度的提高。本文将对人工耳蜗术后残余听力保护相关因素的进展作一综述。     

Cochlear implantation via the round window membrane minimizes trauma to cochlear structures: A histologically controlled insertion study

Objective To evaluate cochlear implant trauma to intracochlear structures when inserting the electrode via the round window membrane.

Material and methods Eight fresh human temporal bones were evaluated histologically after insertion using two types of cochlear implant array. Bones underwent a special fixation and embedding procedure that allowed sectioning of undecalcified bone with the electrode in situ. Insertions depths were evaluated radiologically and histologically.

Results All arrays were found in the scala tympani of the cochlea. Basal trauma could be avoided in all but one specimen. The mean depth of insertion was 382.5°. Apically, only one implanted bone showed cochlear trauma exceeding lifting of the basilar membrane.

Conclusion Insertions through the round window membrane were shown to be atraumatic, even in basal cochlear regions. This route of insertion might be very effective for combined electric and acoustic stimulation of the auditory system.     

Round window membrane rupture and acquired sensorineural hearing loss in children

Round window membrane rupture and acquired sensorineural hearing loss in children The aetiology of acquired sensorineural hearing loss includes many conditions. The disparity between the number of children affected by the conditions which are supposed to cause hearing loss and the number of children who are actually deaf, has never been satisfactorily explained. Clinical features observed in children with surgically proven round window membrane rupture have been noted in all conventional aetiological groups. These features include otitis media, doubt about the hearing status in early life, disturbance of balance and other occasional neurological phenomena. Wide variation in the appearance of round window niche has been observed in children with secretory otitis and similar appearances have been observed in children with proven round window membrane rupture. The appearances may represent a reaction to perilymph. Round window membrane rupture is probably common and may prove to be a unifying factor for many cases of acquired sensorineural hearing loss. Occasional neurological phenomena may be related to it.     

Cochlear volume as a predictive factor for residual-hearing preservation after conventional cochlear implantation

Objective: The preservation of residual hearing after conventional cochlear implantation (CI) is frequently observed when atraumatic soft surgery is adopted. The purpose of this study was to elucidate the predictive factors for residual hearing preservation after atraumatic CI.

Patients: This study included 46 patients who underwent CI based on an atraumatic technique using a standard-length flexible electrode implant through a round window approach.

Main outcome measure: Cochlear volume was measured using magnetic resonance imaging (MRI). Cochlear duct length (CDL) was taken as the length of the scala media measured using computed tomography (CT). The association between residual hearing preservation and cochlear volume/CDL was then examined.

Result: Cochlear volume and CDL were significantly larger in patients with complete hearing preservation than in those with hearing loss. Multivariate logistic regression analysis revealed that cochlear volume was a significant predictive factor for residual hearing preservation.

Conclusion: Residual hearing preservation after conventional CI was observed in patients with a larger cochlear volume and longer CDL. Cochlear volume could be a predictive factor for residual hearing preservation after conventional CI.     

人工耳蜗植入后对侧耳是否联合使用助听器声调识别的对比研究

目的 探讨人工耳蜗植入后对侧耳联合使用助听器对声调识别的影响;同时探讨人工耳蜗开机时间、康复训练时间、听障儿童的学习能力等因素对声调识别的影响。 方法 选择3~7岁的人工耳蜗植入儿童27例,采用《言语听觉反应评估》(EARS)中的“封闭式声调测试”作为测试材料,分别单独使用人工耳蜗(CI)和在人工耳蜗对侧耳联合使用助听器(CIHA)在安静和噪声两种环境下进行声调识别的测试,使用SPSS 17.0对测试结果进行统计学分析。 结果 无论在安静环境还是噪声环境下,CIHA的声调测试成绩均优于CI,此优势在噪声环境下更明显;人工耳蜗开机时间、康复训练时间较长者声调测试成绩均优于较短者;听障儿童的希-内学习能力测试结果学习能力DIQ≥100与DIQ<100者声调测试成绩差异无统计学意义。 结论 建议听障儿童人工耳蜗植入后对侧耳联合使用助听器,但助听器需要优化和调整。     

A new electrode for residual hearing preservation in cochlear implantation: first clinical results

Conclusion. A so far unattained high rate (100%) of residual hearing preservation in cochlear implantation for electric-acoustic stimulation could be achieved using sophisticated surgical techniques in combination with the MedEl Flex EAS electrode. Objectives. This study aimed to gather first audiological and surgical results from the experience gained with the new MedEl Flex EAS electrode array. Patients and methods. Nine patients (aged 7.62–71.32 years) with profound high frequency hearing loss were supplied with this atraumatic electrode, which was designed to preserve residual hearing despite intracochlear insertion of an electrode array. All patients were implanted by the same surgeon. Results. Hearing preservation was achieved in all patients (complete preservation 44.44%) after a mean follow-up period of 9.73 months. Mean monosyllabic test scores improved from 9% correct with the hearing aid alone to 48% with the cochlear implant and to 65% in the electric-acoustic mode.     

Residual hearing in cochlear implant patients

Preservation of residual hearing should be a desirable outcome of implant surgery. Prevention of neural degeneration due to loss of residual hair cells, together with the continuous progress in cochlear implant technology should be able to preserve cochlear integrity as well as possible. The degree of hearing preservation may vary depending on surgical approach, maximum insertion depth and other factors not uniformly considered to date. The aim of this retrospective case controlled study is to evaluate residual hearing after cochlear implant surgery. In particular, we analyzed data obtained with use of two different kinds of electrode arrays, with and without rigid introductor (stylet). We report the results on 37 patients with measurable preoperative hearing thresholds, mean age of 28 years (5–70 years), having the following implants: seven Advanced Bionics^®, four Med-El^®, 24 Cochlear^®, two MXM^®; 19 of them were performed using the stylet and the other 18 without it. A minimally invasive surgical approach was performed with a short retroauricular incision and a 1.2 mm cochleostomy. A complete electrode array insertion was obtained in all patients. Responses to pure-tone stimuli were measured for each ear in pre-implantation conditions and 3–12 months after surgery. After implantation 14 patients (38%) showed no hearing threshold variation, 29 (78%) maintained an appreciable hearing threshold level in the implanted ear, 8 (22%) had a total loss of residual hearing. Median increases of threshold levels were, in all 37 studied patients, 5, 10, 10 and 5 dB HL, respectively, for 125, 250, 500 and 1 kHz. For the 18 patients having implants without the stylet median increases of threshold levels were 0, 10, 5 and 7 dB HL; in the stylet group, they were 10, 5, 5 and 10 dB HL. On a comparison between the stylet and the non-stylet group, no significant differences in mean hearing threshold worsening were found. Data seem to suggest that cochlear function is less sensitive to mechanical trauma during implant surgery than was thought. Besides, electrode array stiffness seems not to influence preservation of cochlear residual functional integrity. Finally, the authors hypothesize a direct spiral ganglion activation under strong mechanical stimulation.     

Genetic testing has the potential to impact hearing preservation following cochlear implantation

Abstract

Background: Recent advances in less-invasive surgery and electrode design allow for a high degree of hearing preservation (HP) after cochlear implantation (CI), although residual hearing still deteriorates in some patients. To date, the factors predictive of preserving residual hearing remain a controversial topic.

Objective: The aim of this study was to investigate the predictive factors, including the etiology of hearing loss (HL) as a patient-related factor, influencing residual HP after CI.

Methods: Forty-four patients (50 ears, 41 families) with residual acoustic hearing who underwent CI were included. Auditory thresholds before and at 6 months after initial activation were measured. Genetic testing was performed to identify the responsible genes for HL.

Results: We identified the cause of HL in 21 families (51.2%). HP was marginally correlated with age at implantation, while it was independent of pre-operative low-frequency hearing thresholds, cochlear duct length, and electrode length. We found that patients who had pathogenic variants in the CDH23, MYO7A, or MYO15A gene showed statistically better HP scores compared with patients with HL due to other causes (p?=?.002).

Conclusions: Identification of the etiology of HL using genetic testing is likely to facilitate the prediction of HP after implant surgery.     

有低频残余听力感音神经聋的人工耳蜗植入术

目的介绍一种有低频残余听力感音神经聋的人工耳蜗植入技术,探讨人工耳蜗植入手术对有残余听力患者的治疗效果和价值。方法15例有残余听力的患者接受了保护残余听力的人工耳蜗植入手术。术中电极植入深度在19mm～24mm左右。术后分别检测单纯使用助听器、单纯使用人工耳蜗、人工耳蜗结合助听器三种不同状态下的听力。结果15例患者中,有13例术后残余听力保存良好,仅分别丢失5～20dB听力,但另2例术后残余听力全部丧失。术后在安静、信噪比15dB和10dB三种不同状态下的言语测试结果显示,人工耳蜗结合助听器使用者测试得分始终保持在很高水平;单纯使用人工耳蜗者也有较好的成绩,但在信噪比达10dB的条件下,测试成绩下降;而单纯使用助听器者,不仅在安静状态下听力成绩不甚理想,一旦加入竞争性噪声,听力测试成绩急剧下降。结论保护和利用残余听力的人工耳蜗植入技术,使人工耳蜗植入手术对象从重度或极重度聋扩大到高频为重度或极重度聋,低频（≤500Hz）为中、轻度聋的患者。接受这项技术患者的听力和言语识别能力均明显优于其单纯配戴助听器和单纯使用人工耳蜗时的听力和言语识别能力。     

A case of improved hearing with cochlear implantation in Gaucher disease type 1

Gaucher disease is a lysosomal storage disorder that is caused by congenital defective function of the enzyme glucocerebrosidase. Glucocerebroside that is not hydrolyzed by glucocerebrosidase mainly accumulates in the reticular tissue. We describe a Japanese boy with Gaucher disease type 1 who developed bilateral profound sensorineural hearing loss within approximately 4 years. We performed cochlear implantation initially on his right ear and again on his left ear 5 months later. The cochlear implants were successfully utilized with a speech discrimination score of 95% on a Japanese sentence recognition test. There are many reports of central hearing loss in Gaucher disease type 2 or 3. However, to the best of our knowledge, this is the first report of profound inner ear hearing loss with Gaucher disease. It also appears to be the first record of cochlear implantation for Gaucher disease. Cochlear implants may be useful for sensorineural hearing loss in patients with Gaucher disease without neurological symptoms other than hearing loss.     

Cochleostomy site: Implications for electrode placement and hearing preservation

Conclusions. With recent increased interest in minimizing intracochlear trauma and preserving residual hearing during cochlear implantation, increased attention must be paid to the cochleostomy site. The results of this paper demonstrate that the cochleostomy must be made inferior, rather than anterior, to the round window to ensure scala tympani insertion and to decrease the likelihood of insertion-induced intracochlear damage during electrode insertion. Objective. To describe the complex anatomy of the hook region of the cochlea, specifically in relation to the optimal placement of the cochleostomy for cochlear implant electrode insertion to potentially achieve hearing preservation. The authors believe that previous industry recommendations and described surgical techniques have resulted in cochleostomies being placed in anatomical positions that possibly result in electrode insertions that damage the basilar membrane and/or other cochlear structures. Material and methods. The results of a number of temporal bone studies were reviewed with attention being paid to the anatomical relationship of the basilar membrane and spiral ligament to the round window membrane. For different cochleostomy sites the potential for damage to intracochlear structures, particularly the basilar membrane and organ of Corti, was assessed. Results. The review of electrode insertion studies into human temporal bones, as well as a post-mortem anatomical study of implanted temporal bones, showed an increased risk of scala vestibuli insertions and insertion-induced damage to intracochlear structures when the cochleostomy was performed more anterior to the round window. These results were endorsed by studies detailing the anatomy of the hook region of the cochlea.     

Radiologic anatomy of the round window relevant to cochlear implantation and inner ear drug delivery

ObjectiveTo determine anatomic relationships and variation of the round window membrane to bony surgical landmarks on computed tomography.Study designRetrospective imaging review.Methods100 temporal bone images were evaluated. Direct measurements were obtained for membrane position. Vector distances and angulation from umbo and bony annulus were calculated from image viewer software coordinates.ResultsThe angle of round window membrane at junction with cochlear basal turn was (42.1 ± 8.6)°. The membrane''s position relative to plane of the facial nerve through facial recess was (14.7 ± 5.2)° posterior from a reference line drawn through facial recess to carotid canal. Regarding transtympanic drug delivery, the round window membrane was directed 4.1 mm superiorly from the inferior annulus and 5.4 mm anteriorly from the posterior annulus. The round window membrane on average was angled superiorly from the inferior annulus (77.1 ± 27.9)° and slightly anteriorly from the posterior annulus (19.1 ± 11.1°). The mean distance of round window membrane from umbo was 4 mm and posteriorly rotated 30° clockwise from a perpendicular drawn from umbo to inferior annulus towards posterior annulus. Together, these measurements approximate the round window membrane in the tympanic membrane''s posteroinferior quadrant.ConclusionsThese radiologic measurements demonstrate normal variations seen in round window anatomy relative to facial recess approach and bony tympanic annulus, providing a baseline to assess round window insertion for cochlear implantation and outlines anatomic factors affecting transtympanic drug delivery.     

Effects of intraoperatively applied glucocorticoid hydrogels on residual hearing and foreign body reaction in a guinea pig model of cochlear implantation

Conclusion: The intraoperative application of glucocorticoid-loaded hydrogels seems to cause a reduction in neutrophil infiltration. No beneficial effect on hearing thresholds was detected. Objectives: To evaluate the application of dexamethasone- and triamcinolone acetonide-loaded hydrogels for effects on hearing preservation and foreign body reaction in a guinea pig model for cochlear implantation (CI). Methods: A total of 48 guinea pigs (n = 12 per group) were implanted with a single channel electrode and intraoperatively treated with 50 μl of a 20% w/v poloxamer 407 hydrogel loaded with 6% dexamethasone or 30% triamcinolone acetonide, a control hydrogel, or physiological saline. Click- and tone burst-evoked compound action potential thresholds were determined preoperatively and directly postoperatively as well as on days 3, 7, 14, 21, and 28. At the end of the experiment, temporal bones were prepared for histological evaluation by a grinding/polishing technique with the electrode in situ. Three ears per treatment group were serially sectioned and evaluated for histological alterations. Results: The intratympanic application of glucocorticoid-loaded hydrogels did not improve the preservation of residual hearing in this cochlear implant model. The foreign body reaction to the electrode appeared reduced in the glucocorticoid-treated animals. No correlation was found between the histologically described trauma to the inner ear and the resulting hearing threshold shifts.