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The present video reports the surgical removal of an intralabyrinthine schwannoma. The video contains patient's medical history, preoperative radiological evaluations and detailed description of surgical steps of the procedure, consisting in labyrinthectomy, cochleostomy and insertion of a dummy electrode in the preserved cochlear lumen within the context of a subtotal petrosectomy.
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Orelha Interna , Neurilemoma , Neuroma Acústico , Procedimentos Cirúrgicos Otológicos , Humanos , Cóclea/diagnóstico por imagem , Cóclea/cirurgia , Neurilemoma/diagnóstico por imagem , Neurilemoma/cirurgia , Neuroma Acústico/diagnóstico por imagem , Neuroma Acústico/cirurgia , Procedimentos Cirúrgicos Otológicos/métodosRESUMO
INTRODUCTION: Round window approach and cochleostomy approach can have different depth of electrode insertion during cochlear implantation which itself can alter the audiological outcomes in cochlear implant. OBJECTIVE: The current study was conducted to determine the difference in the depth of electrode insertion via cochleostomy and round widow approach when done serially in same temporal bone. METHODOLOGY: This is a cross-sectional study conducted in the Department of Otorhinolaryngology in conjunction with Department of Anatomy and Department of Diagnostic and Interventional Radiology over a period of 1 year. 12-electrode array insertion was performed via either approach (cochleostomy or round window) in the cadaveric temporal bone. HRCT temporal bone scan of the implanted temporal bone was done and depth of insertion and various cochlear parameters were calculated. RESULT: A total of 12 temporal bones were included for imaging analysis. The mean cochlear duct length was 32.892 mm; the alpha and beta angles were 58.175° and 8.350°, respectively. The mean angular depth of electrode insertion via round window was found to be 325.2° (SD = 150.5842) and via cochleostomy 327.350 (SD = 112.79) degree and the mean linear depth of electrode insertion via round window was found to be 18.80 (SD = 4.4962) mm via cochleostomy 19.650 (SD = 3.8087) mm, which was calculated using OTOPLAN 1.5.0 software. There was a statically significant difference in linear depth of insertion between round window and cochleostomy. Although the angular depth of insertion was higher in CS group, there was no statistically significant difference with round window type of insertion. CONCLUSION: The depth of electrode insertion is one of the parameters that influences the hearing outcome. Linear depth of electrode insertion was found to be more in case of cochleostomy compared to round window approach (p = 0.075) and difference in case of angular depth of electrode insertion existed but not significant (p = 0.529).
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Cadáver , Cóclea , Implante Coclear , Implantes Cocleares , Janela da Cóclea , Osso Temporal , Humanos , Janela da Cóclea/cirurgia , Implante Coclear/métodos , Osso Temporal/cirurgia , Osso Temporal/diagnóstico por imagem , Estudos Transversais , Cóclea/cirurgia , Cóclea/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Eletrodos ImplantadosRESUMO
Background: The persistent stapedial artery (PSA) is a rare congenital vascular malformation involving the middle ear. It is usually associated with pulsatile tinnitus and/or conductive hearing loss and can account for multiple risks during middle ear surgery. Case Report: we present a case of a 9-year-old male child with conductive hearing loss and persistent stapedial artery in his right ear, who was admitted to our ENT Department for hearing loss. During surgery, we discovered PSA along with congenital stapes agenesis and oval window atresia, as well as an abnormal trajectory of the mastoid segment of the facial nerve. After ossicular reconstruction (transcanal total ossicular replacement prosthesis) with cochleostomy, no surgical complications were recorded and hearing improvement was monitored by pre- and postoperative audiometry. Conclusion: Stapedial artery is a rare anatomical middle ear abnormality that can prevent proper surgical hearing restoration and can be associated with other simultaneous temporal bone malformations.
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Prótese Ossicular , Estribo , Masculino , Criança , Humanos , Estribo/anormalidades , Estribo/irrigação sanguínea , Perda Auditiva Condutiva/etiologia , Perda Auditiva Condutiva/cirurgia , Orelha Média/anormalidades , Orelha Média/cirurgia , Artérias/anormalidadesRESUMO
OBJECTIVE: To assess data regarding round window (RW) visibility and surgical approaches in cochlear implant cases, and to describe and analyze surgical steps relevant for the RW approach in cochlear implantation. STUDY DESIGN: Prospective clinical study. METHODS: A questionnaire was completed by surgeons after each of altogether 110 cochlear implantations. Round window membrane (RWM) visibility was graded according to the St Thomas Hospital (STH) classification. RESULTS: Performing different surgical steps during the preparation of the RW niche, the RWM could be fully exposed (STH Type I) in 87%. A RW approach could be used for electrode insertion in 89% of the adult and 78% of the pediatric cases. The distribution of RW types differed significantly between adults and children. Drilling of the superior bony lip was the surgical step most frequently needed in adult as well as pediatric cases to obtain optimal RW exposure. CONCLUSION: In children, optimized surgical exposure of the RW niche resulted in only 52% full RWM visibility; whereas in adults, this could be achieved in 87%. The facial nerve (FN) had to be exposed at the level of the posterior tympanotomy in more than 70% of pediatric cases with full RWM visibility; while in adult cases with 100% visibility, such specific exposure was necessary in only 33%. Thus, surgical preparation of the RW niche seems to be more demanding in children than in adults.
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Implante Coclear , Implantes Cocleares , Adulto , Criança , Eletrodos Implantados , Humanos , Estudos Prospectivos , Janela da Cóclea/cirurgiaRESUMO
Sensoneural hearing loss is a polyetiological disease, which is often a secondary reflection of systemic pathology and is associated with damage of the cochlea and auditory nerve receptors. An important point in the surgical stage of cochlear implantation is the introduction of an implant active electrode into the cochleostomy spiral channel through the cochleostoma or round window. However, the issue of intra-cochlear structures surgical trauma in such surgical intervention seems to be very important, as it may reduce the success of subsequent rehabilitation. Therefore, the study of the anatomy of the round window and adjuscent areas was the objective of this work.
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Implante Coclear , Implantes Cocleares , Perda Auditiva , Cóclea/cirurgia , Eletrodos Implantados , Humanos , Janela da Cóclea/cirurgiaRESUMO
OBJECTIVE: The objective of this study was to examine whether cochlear implantation using the round window (RW) route versus cochleostomy achieves comparable electrode impedance and hearing results. METHODS: This retrospective analysis included 40 patients receiving a cochlear implant (REZ-1): 20 using the RW approach and the remaining 20 using cochleostomy. Electrode impedance and tone, vowel, consonant, disyllable and sentence perception were measured during and after the implantation. RESULTS: Electrode impedance did not differ significantly between the 2 groups at any time points [F(1, 38) = 1.84; p = 0.184]: 1.87, 5.16, 6.47 and 6.70 kΩ in the RW group versus 2.86, 5.33, 6.92 and 8.16 kΩ in the cochleostomy group at 0, 1, 3 and 12 months, respectively. There was no significant difference between the RW and cochleostomy groups for tone (77.50 vs. 80.50%; p = 0.472), vowel (77.70 vs. 78.65%; p = 0.760), consonant (75.50 vs. 78.25%; p = 0.443), disyllable (78.60 vs. 81.50%; p = 0.317) and sentence (50.90 vs. 52.50%; p = 0.684) perception at 12 months. CONCLUSION: The RW approach is comparable to cochleostomy in electrode placement as reflected by impedance and function as reflected by tone, vowel, consonant, disyllable and sentence perception.
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Cóclea/cirurgia , Implante Coclear/métodos , Surdez/cirurgia , Janela da Cóclea/cirurgia , Adulto , Implantes Cocleares , Surdez/fisiopatologia , Impedância Elétrica , Feminino , Testes Auditivos , Humanos , Masculino , Estudos Retrospectivos , Percepção da FalaRESUMO
Intracochlear schwannomas can occur either as an extension of a larger tumor from the internal auditory canal, or as a solitary labyrinthine tumor. They are currently removed via a translabyrinthine approach extended to the basal turn, adding a transotic approach for tumors lying beyond the basal turn. Facial bridge cochleostomy may be associated with the translabyrinthine approach to enable the whole cochlea to be approached without sacrificing the external auditory canal and tympanum. We describe seven cases, five of which underwent cochlear schwannoma resection with facial bridge cochleostomy, one case with the same procedure for a suspect tumor and one, previously subjected to radical tympanomastoidectomy, who underwent schwannoma resection via a transotic approach. Facial bridge cochleostomy involved removing the bone between the labyrinthine and tympanic portions of the fallopian canal, and exposing the cochlea from the basal to the apical turn. Patients' recovery was uneventful, and long-term magnetic resonance imaging showed no residual tumor. Facial bridge cochleostomy can be a flexible extension of the translabyrinthine approach for tumors extending from the internal auditory canal to the cochlea. The transcanal approach is suitable for the primary exclusive intralabyrinthine tumor. The indications for the different approaches are discussed.
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Neoplasias da Orelha , Neurilemoma , Neuroma Acústico , Procedimentos Cirúrgicos Otológicos , Adulto , Dissecação/efeitos adversos , Dissecação/métodos , Meato Acústico Externo/cirurgia , Neoplasias da Orelha/patologia , Neoplasias da Orelha/cirurgia , Orelha Interna/diagnóstico por imagem , Orelha Interna/patologia , Orelha Interna/cirurgia , Feminino , Humanos , Itália , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Neoplasia Residual/diagnóstico , Neoplasia Residual/prevenção & controle , Neurilemoma/patologia , Neurilemoma/cirurgia , Neuroma Acústico/patologia , Neuroma Acústico/cirurgia , Procedimentos Cirúrgicos Otológicos/efeitos adversos , Procedimentos Cirúrgicos Otológicos/métodos , Avaliação de Processos e Resultados em Cuidados de Saúde , Estudos Retrospectivos , Membrana Timpânica/cirurgiaRESUMO
The goal of this study was to evaluate, in the hands of an inexperienced surgeon, the cochleostomy location of an endaural approach (MINV) compared to the conventional posterior tympanotomy (MPT) approach. Since 2010, we use in the ENT department of Nice a new surgical endaural approach to perform cochlear implantation. In the hands of an inexperienced surgeon, the position of the cochleostomy has not yet been studied in detail for this technique. This is a prospective study of 24 human heads. Straight electrode arrays were implanted by an inexperienced surgeon: on one side using MPT and on the other side using MINV. The cochleostomies were all antero-inferior, but they were performed through an endaural approach with the MINV or a posterior tympanotomy approach with the MPT. The positioning of the cochleostomies into the scala tympani was evaluated by microdissection. Cochleostomies performed through the endaural approach were well placed into the scala tympani more frequently than those performed through the posterior tympanotomy approach (87.5 and 16.7 %, respectively, p ≤ 0.001). This study highlights the biggest challenge for an inexperienced surgeon to achieve a reliable cochleostomy through a posterior tympanotomy, which requires years of experience. In case of an uncomfortable view through a posterior tympanotomy, an inexperienced surgeon might be able to successfully perform a cochleostomy through an endaural (combined approach) or an extended round window approach in order to avoid opening the scala vestibuli.
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Competência Clínica , Implante Coclear/métodos , Ventilação da Orelha Média/métodos , Implantes Cocleares , Humanos , Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Modelos Anatômicos , Estudos Prospectivos , Janela da Cóclea/cirurgia , Rampa do Tímpano/cirurgia , Osso Temporal/patologia , Osso Temporal/cirurgiaRESUMO
The aim of this study was to assess the mental representation of the insertion axis of surgeons with different degrees of experience, and reproducibility of the insertion axis in repeated measures. A mastoidectomy and a posterior tympanotomy were prepared in five different artificial temporal bones. A cone-beam CT was performed for each temporal bone and the data were registered on a magnetic navigation system. In these five temporal bones, 16 surgeons (3 experts; >50 cochlear implant surgery/year; 7 fellows with few cochlear implant experience, and 6 residents) were asked to determine the optimal insertion axis according to their mental representation. Compared to a planned ideal axis, the insertion axis was better determined by the experts with higher accuracy (axial: 7° ± 1.5°, coronal: 6° ± 1.5°) than fellows (axial: 14° ± 1.7°, coronal: 13° ± 1.7°; p < 0.05), or residents (axial: 15° ± 1.5°; p < 0.001, coronal: 17° ± 1.9°; p < 0.001). This study suggests that mental representation of the cochlea is experience-dependent. A high variation of the insertion axis to the scala tympani can be observed due to the complexity of the temporal bone anatomy and lack of landmarks to determine scala tympani orientation. Navigation systems can be used to evaluate and improve mental representation of the insertion axis to the scala tympani for cochlear implant surgery.
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Competência Clínica/normas , Implante Coclear , Cirurgiões , Cirurgia Assistida por Computador , Cóclea/diagnóstico por imagem , Cóclea/cirurgia , Implante Coclear/métodos , Implante Coclear/psicologia , Tomografia Computadorizada de Feixe Cônico/métodos , Precisão da Medição Dimensional , Humanos , Processo Mastoide/diagnóstico por imagem , Processo Mastoide/cirurgia , Testes de Navegação Mental , Reprodutibilidade dos Testes , Cirurgiões/psicologia , Cirurgiões/normas , Cirurgia Assistida por Computador/métodos , Cirurgia Assistida por Computador/normas , Osso Temporal/diagnóstico por imagem , Osso Temporal/cirurgiaRESUMO
The aim of this study was to compare the outcomes of vestibular tests and the residual hearing of patients who have undergone full insertion cochlear implant surgery using the round window approach with a hearing preservation protocol (RW-HP) or the standard cochleostomy approach (SCA) without hearing preservation. A prospective study of 34 adults who underwent unilateral cochlear implantation was carried out. One group was operated using the RW-HP (n = 17) approach with Med-El +Flex(SOFT) electrode array with full insertion, while the control group underwent a more conventional SCA surgery (n = 17) with shorter perimodiolar electrodes. Assessments of residual hearing, cervical vestibular-evoked myogenic potentials (cVEMP), videonystagmography, subjective visual vertical/horizontal (SVH/SVV) were performed before and after surgery. There was a significantly (p < 0.05) greater number of subjects who exhibited complete or partial hearing preservation in the deep insertion RW-HP group (9/17) compared to the SCA group (2/15). A higher degree of vestibular loss but a lower degree of vertigo symptoms could be seen in the RW-HP group, but the differences were not statistically significant. It is possible to preserve residual hearing to a certain extent also with deep insertion. Full insertion with hearing preservation was less harmful to residual hearing particularly at 125 Hz (p < 0.05), than was the standard cochleostomy approach.
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Implante Coclear/métodos , Janela da Cóclea/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Implantes Cocleares , Feminino , Testes Auditivos , Humanos , Masculino , Pessoa de Meia-Idade , Nistagmo Fisiológico , Estudos Prospectivos , Potenciais Evocados Miogênicos Vestibulares , Testes de Função Vestibular , Vestíbulo do Labirinto/fisiologia , Adulto JovemRESUMO
Background: Cerebrospinal fluid (CSF) gusher is a common complication experienced during cochlear implantation in patients with structural deformities in the inner ear. Objectives: This study aimed to investigate the incidence of CSF gusher, risk factors, and outcomes in patients during cochlear implantation. Methods: This systematic review and meta-analysis were guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses model. Studies used in the analysis were identified through a comprehensive search in Google Scholar and PubMed. Results: The analysis was performed using 13 retrospective studies. The incidence of CSF gusher was 5% (95% CI: 3%-9%). CSF gusher was more prevalent among patients with inner-ear malformation (IEM) than without IEM odds ratio = 63.01 (95% CI: 9.85-403.11, P < .00001, I2 = 88%). For incomplete partition (IP), CSF gusher in the IP-I group was 48% (95% CI: 25%-71%, I2 = 0%), 19% in IP-II, 86% in IP-III, 40% in the common cavity, 26% in cochlear hypoplasia, and 27% in patients with enlarged vestibula aqueduct. Conclusion: The CSF gusher incidences were determined to be 5%. Patients with IEM are at increased risk of experiencing CSF gusher during cochlear implant surgery. Therefore, precise scanning reports should be produced in preoperational phase to inform proper management techniques to reduce the chances of intraoperative complications, including CSF gusher.
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Objective: To better characterize the cochlear apex in relation to surgically relevant landmarks to guide surgeons and improve procedural success of apical electrode placement. Study Design: Retrospective image analysis. Setting: Tertiary referral center. Patients: Cochlear implant recipients with available preoperative computed tomography (CT) imaging. Intervention: None. Main Outcome Measure: Cochlear dimensions and cochlear apex distance measures to surgically relevant middle ear landmarks and critical structures. Results: Eighty-two temporal bone CT scans were analyzed utilizing multiplanar reformats. The average lateral width of promontory bone over the cochlear apex was 1.2 mm (standard deviation [SD], 0.3). The anteroposterior distance from the round window (avg, 4.2 mm; SD, 0.5), oval window (avg, 3.3 mm; SD, 0.3), cochleariform process (avg, 2.3; SD, 0.5), and superior-inferior distance from the cochleariform process (avg, -0.9; SD, 0.8) to the cochlear apex were measured. The relationship of the cochlear apex to critical structures was highly variable.A newly developed stapes vector was created and found to mark the posterior/superior boundary of the apex in 94% of patients. When a vector parallel to the stapes vector was drawn through the round window, it marked the anterior/inferior boundary of the cochlear apex in 89% of patients. Conclusions: This study assists in characterizing cochlear apex anatomy and its relation to surrounding structures as a means of improving procedural accuracy and reducing trauma during apical cochleostomy. Understanding both distance relationships and expected boundaries of the apex could help to inform future surgical approaches.
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OBJECTIVE: This study aims to discern the disparities in the electrode-to-modiolus distance (EMD) between cochleostomy and round window approaches when performed sequentially in the same temporal bone. Additionally, the study seeks to identify the cochlear metrics that contribute to these differences. METHODOLOGY: A cross-sectional study was conducted, involving the sequential insertion of a 12-electrode array through both round window and cochleostomy approaches in cadaveric temporal bones. Postimplantation high-resolution CT scans were employed to calculate various parameters. RESULTS: A total of 12 temporal bones were included in the imaging analysis, revealing a mean cochlear duct length of 32.892 mm. The EMD demonstrated a gradual increase from electrode 1 (C1) in the apex (1.9 ± 0.07 mm; n = 24) to electrode 12 (C12) in the basal turn (4.6 ± 0.24 mm; n = 12; p < 0.01). Significantly higher EMD values were observed in the cochleostomy group. Correlation analysis indicated a strong positive correlation between EMD and cochlear perimeter (CP) (rs = 0.64; n = 12; p = 0.03) and a strong negative correlation with the depth of insertion (DOI) in both the middle and basal turns (rs = - 0.78; n = 20; p < 0.01). Additionally, EMD showed a strong negative correlation with the DOI-CP ratio (rs = -0.81; n = 12; p < 0.01). CONCLUSION: The cochleostomy group exhibited a significantly higher EMD compared with the round window group. The strong negative correlation between EMD and DOI-CP ratio suggests that in larger cochleae with shallower insertions, EMD is greater than in smaller cochleae with deeper insertions. LEVEL OF EVIDENCE: NA Laryngoscope, 134:4736-4744, 2024.
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Cadáver , Cóclea , Implante Coclear , Implantes Cocleares , Janela da Cóclea , Osso Temporal , Tomografia Computadorizada por Raios X , Humanos , Estudos Transversais , Implante Coclear/métodos , Osso Temporal/diagnóstico por imagem , Osso Temporal/cirurgia , Osso Temporal/anatomia & histologia , Janela da Cóclea/cirurgia , Janela da Cóclea/diagnóstico por imagem , Janela da Cóclea/anatomia & histologia , Cóclea/diagnóstico por imagem , Cóclea/cirurgia , Cóclea/anatomia & histologia , Eletrodos ImplantadosRESUMO
Introduction: For experimental studies on sound transfer in the middle ear, it may be advantageous to perform the measurements without the inner ear. In this case, it is important to know the influence of inner ear impedance on the middle ear transfer function (METF). Previous studies provide contradictory results in this regard. With the current study, we investigate the influence of inner ear impedance in more detail and find possible reasons for deviations in the previous studies. Methods: 11 fresh frozen temporal bones were prepared in our study. The factors related to inner ear impedance, including round window membrane stiffness, cochleostomy, cochlea fluid and cochlea destruction were involved in the experimental design. After measuring in the intact specimen as a reference (step 1), the round window membrane was punctured (step 2), then completely removed (step 3). The cochleostomy was performed (step 4) before the cochlear fluid was carefully suctioned through scala tympani (step 5) and scala vestibuli (step 6). Finally, cochlea was destroyed by drilling (step 7). Translational and rotational movement of the stapes footplate were measured and calculated at each step. The results of the steps were compared to quantify the effect of inner ear impedance changing related to the process of cochlear drainage. Results: As the inner ear impedance decreases from step 1 to 7, the amplitudes of the METF curves at each frequency gradually increase in general. From step 6 on, the measured METF are significantly different with respect to the intact group at high frequencies above 3 kHz. The differences are frequency dependent. However, the significant decrement of rotational motion appears at the frequencies above 4.5 kHz from the step 5. Conclusion: This study confirms the influence of inner ear impedance on METF only at higher frequencies (≥3 kHz). The rotational motions are more sensitive to the drainage of fluid at the higher frequency. Study results that found no influence of cochlea impedance may be due to incomplete drainage of the cochlea.
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Relapsing polychondritis is an autoimmune disorder causing inflammation of cartilaginous structures, sensory epithelium, and cardiovascular system. Hearing loss is a rare and dreadful complication of this pathology. We report a case of relapsing polychondritis in a 38-year-old female who developed gradually progressive bilateral profound hearing loss. She did not have any improvement with medical management. Cochlear implantation was performed to rehabilitate her hearing. As the scala tympani was obliterated, a scala vestibuli insertion was performed. A complete insertion was possible with a compressed electrode, and she had good evoked compound action potential scores. Her categories of auditory performance scores were 6 at the end of one year. Patients with relapsing polychondritis can progress to profound hearing loss in rare cases and should be carefully followed up to identify early labyrinthine ossification. A scala vestibuli insertion can be performed with good outcomes in cases with ossification involving scala tympani. The surgeon should be ready for a middle-turn cochleostomy or a drill-out procedure in patients with advanced ossification.
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Cochlear implant electrode array misplacement is a rare but serious complication that may result in failure of hearing rehabilitation, non-auditory percepts, vestibular disturbance, or damage to adjacent neurovascular structures. We present a case of an elderly patient who suffered electrode array misplacement into the posterior semicircular canal, resulting in vestibular symptoms and severe downstream sequelae. The risk of misplacement may be higher in patients with a history of chronic otitis media or prior otologic surgery, and with the use of pre-curved electrode arrays. Electrophysiological testing and intraoperative imaging may allow for early detection and intervention in these cases. Laryngoscope, 133:175-177, 2023.
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Implante Coclear , Implantes Cocleares , Humanos , Idoso , Implantes Cocleares/efeitos adversos , Implante Coclear/efeitos adversos , Implante Coclear/métodos , Cóclea/cirurgia , Eletrodos Implantados/efeitos adversos , Canais Semicirculares/cirurgiaRESUMO
Introduction: Electrocochleography (ECochG) is increasingly used in cochlear implant (CI) surgery, in order to monitor the effect of insertion of the electrode array aiming to preserve residual hearing. However, obtained results are often difficult to interpret. Here we aim to relate changes in ECochG responses to acute trauma induced by different stages of cochlear implantation by performing ECochG at multiple time points during the procedure in normal-hearing guinea pigs. Materials and methods: Eleven normal-hearing guinea pigs received a gold-ball electrode that was fixed in the round-window niche. ECochG recordings were performed during the four steps of cochlear implantation using the gold-ball electrode: (1) Bullostomy to expose the round window, (2) hand-drilling of 0.5-0.6 mm cochleostomy in the basal turn near the round window, (3) insertion of a short flexible electrode array, and (4) withdrawal of electrode array. Acoustical stimuli were tones varying in frequency (0.25-16 kHz) and sound level. The ECochG signal was primarily analyzed in terms of threshold, amplitude, and latency of the compound action potential (CAP). Midmodiolar sections of the implanted cochleas were analyzed in terms of trauma to hair cells, modiolar wall, osseous spiral lamina (OSL) and lateral wall. Results: Animals were assigned to cochlear trauma categories: minimal (n = 3), moderate (n = 5), or severe (n = 3). After cochleostomy and array insertion, CAP threshold shifts increased with trauma severity. At each stage a threshold shift at high frequencies (4-16 kHz) was accompanied with a threshold shift at low frequencies (0.25-2 kHz) that was 10-20 dB smaller. Withdrawal of the array led to a further worsening of responses, which probably indicates that insertion and removal trauma affected the responses rather than the mere presence of the array. In two instances, CAP threshold shifts were considerably larger than threshold shifts of cochlear microphonics, which could be explained by neural damage due to OSL fracture. A change in amplitudes at high sound levels was strongly correlated with threshold shifts, which is relevant for clinical ECochG performed at one sound level. Conclusion: Basal trauma caused by cochleostomy and/or array insertion should be minimized in order to preserve the low-frequency residual hearing of CI recipients.
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Objective: To characterize normative adult ranges for cochlear promontory thickness relevant to the development of subendosteal and transpromontory electrodes to rehabilitate various neurotologic disorders. Patients: Adults (≥18 years). Intervention: In vivo radiologic assessment using a 192-slice CT scanner (Force-192; Siemens Healthcare) with ultrahigh-resolution scan mode combined and iterative reconstruction. Main Outcome Measure: Cochlear promontory thickness. Results: Among 48 included patients (96 ears), the mean (SD) age was 56 (18) years (range 25-94) and included 25 (52%) women. Of that 12 patients (25%) had osteopenia (n = 6) or osteoporosis (n = 6). The mean (SD) body mass index was 28 (5) kg/m2. The mean (SD) promontory thickness for the 96 temporal bones under study was 1.22 (0.24) mm (range 0.55-1.85). There was not a statistically significant association between age and promontory thickness (correlation coefficient .08; p = .44). Promontory thickness was significantly greater for men than women (mean 1.28 vs. 1.17 mm; p = .03) and increased with increasing body mass index (correlation coefficient .30; p = .004). Last, promontory thickness was significantly less for patients with osteopenia or osteoporosis compared with those without these conditions (mean 1.09 vs. 1.27 mm; p = .002). Conclusions: Cochlear promontory thickness can vary by almost 1.5 mm across patients and is significantly associated with patient sex, body mass index, and comorbid osteopenia/osteoporosis. Subendosteal and transpromontory electrode placement techniques must account for this degree of variability. Level of Evidence: IV.
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To study the postoperative visualisation of the electrode array insertion angle through transcanal Veria approach in both round window and cochleostomy techniques. Retrospective study. Tertiary care centre. 26 subjects aged 2-15 years implanted with a MED-EL STANDARD electrode array (31.5 mm) through Veria technique were selected. 16 had the electrode insertion through the round window, 10 through anteroinferior cochleostomy. DICOM files of postoperative computer tomography (CT) scans were collected and analysed using the OTOPLAN 3.0 software. Examined parameters were cochlear duct length, average angle of insertion depth. Pearson's Correlation Test was utilized for statistical analysis. Average cochlear duct length was 38.12 mm, ranging from 34.2 to 43 mm. Average angle of insertion depth was 666 degrees through round window insertion and 670 degrees through cochleostomy insertion. Pearson's correlation showed no significant difference in average angle of insertion depth between subjects with cochleostomy and round window insertion. Detailed study on the OTOPLAN software has established that there remains no difference between round window insertion or cochleostomy insertion when it comes to electrode array position and placement in the scala tympani. It is feasible to perform round window insertion and cochleostomy insertion through transcanal Veria approach as this technique provides good visualisation. Supplementary Information: The online version contains supplementary material available at 10.1007/s12070-022-03228-5.
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Successful cochlear implantation in the setting of labyrinthitis ossificans is challenging. Various surgical techniques are described to circumvent the region of ossification and retrograde insertion of the electrode array is one such option. While reverse programming is often recommended in the case of retrograde electrode insertion, we present our experience of retrograde electrode insertion for labyrinthitis ossificans, where standard programming was adopted due to patient preference and provided satisfactory outcomes.