Electrode array misplacement is a rare complication of cochlear implant. This article reports an 11-year-old boy who was mistakenly implanted the cochlear electrode array into the superior semicircular canal during the initial cochlear implant. After the diagnosis was confirmed, he underwent a second cochlear implant and the electrode array were successfully implanted into the cochlea. This article conducted a systematic review of the literature on electrode array misplacement, and the causes of electrode array misplacement were analyzed from different implantation position.
Male ; Humans ; Child ; Electrodes, Implanted ; Reoperation ; Cochlea ; Cochlear Implantation ; Cochlear Implants/adverse effects* ; Semicircular Canals/surgery*

Objective: To investigate the application of cochlear nerve action potential (CNAP) monitoring in the resection of vestibular schwannoma, especially evaluating its significance for hearing preservation. Methods: From April 2018 to December 2021, 54 patients with vestibular schwannoma who underwent resection via retrosigmoid approach were collected in Chinese PLA General Hospital. Before surgery, all patients had effective hearing (AAO-HNS grade C or above). Brainstem auditory evoked potential (BAEP) combined with CNAP monitoring was performed during surgery. The CNAP monitoring was combined with continuous monitoring and cochlear nerve mapping. And patients were divided into hearing preservation group and non-preserved group according to postoperative AAO-HNS grade. SPSS 23.0 software was used to analyze the differences of CNAP and BEAP parameters between the two groups. Results: A total of 54 patients completed intraoperative monitoring and data collection, including 25 males (46.3%) and 29 females (53.7%), aged 27-71 years with an average age of 46.2 years. The maximum tumor diameter were (18.1±5.9) mm (range 10-34 mm). All tumors were totally removed with preserved facial nerve function (House-Brackmann grade I-II). The hearing preservation rate of 54 patients was 51.9% (28/54). During surgery, the V wave extraction rate of BAEP waveform was 85.2% (46/54) before tumor resection, 71.4% (20/28) in the hearing preservation group after tumor resection, and disappeared in the hearing preservation group (0/26). CNAP waveform was elicited in 54 patients during operation. Differences were found in the distribution of CNAP waveforms after tumor resection. The waveforms of the hearing-preserving group were triphasic and biphasic, while those in the non-preserving group were low-level and positive. For hearing preservation group, the amplitude of N1 wave after tumor resection was significantly higher than that before tumor resection[14.45(7.54, 33.85)μV vs 9.13(4.88, 23.35)μV, P=0.022]; However, for the non-preserved group, the amplitude of N1 wave after tumor resection was significantly lower than that before tumor resection [3.07(1.96, 4.60)μV vs 6.55(4.54, 9.71)μV, P=0.007]; After tumor resection, the amplitude was significantly higher than that of the unreserved group [14.45(7.54, 33.85)μV vs 3.07(1.96, 4.60)μV, P<0.001]. Conclusions: BAEP combined with CNAP monitoring is conducive to intraoperative hearing protection, and the application of cochlear nerve mapping can prompt the surgeon to avoid nerve injury. The waveform and N1 amplitude of CNAP after tumor resection have a certain value in predicting postoperative hearing preservation status.
Female ; Male ; Humans ; Middle Aged ; Neuroma, Acoustic/surgery* ; Action Potentials ; Evoked Potentials, Auditory, Brain Stem ; Cochlea ; Cochlear Nerve

Humans ; Cochlear Implantation ; Robotic Surgical Procedures ; Cochlea/surgery* ; Robotics

Objective: To investigate the effect of insertion technique and electrode array type on the insertion force of electrode array, and to provide a basis for further optimizing electrode design and facilitating mini-invasive electrode insertion. Methods: Three types of electrode array from Nurotron (Standard Electrode, Slim-medium Electrode, Slim-long Electrode) were studied. from July 2019 to December 2019. These electrode arrays were inserted into the phantom models of the cochlea, manually or robot-assisted(medium speed and low speed). The real-time force during electrode array insertion was recorded by ATI Nano 17 Ti sensors and was analyzed by accessory software. Origin 2020b software was used for statistical processing. Results: The insertion force of all electrode arrays progressively increased with the insertion depth. With the manual technique, the peak force of slim-medium electrode insertion was significantly smaller than that of the standard electrode insertion((71.0±16.6) mN vs (140.9±52.7) mN, Z=3.683, P<0.01), and the peak force of the slim-long electrode insertion was between the peak force of standard electrode and slim-medium electrode(P>0.05). No difference was found in the force variation of insertion among the three electrodes(P>0.05). With medium-speed and low-speed robotic assistance, the peak force characteristics of three electrodes were similar to those with the manual technique, but the force variation of standard electrode insertion ((83.9±9.7) mN/s) at medium speed was significantly larger than that of the slim-long electrode insertion ((69.2±4.0)mN/s), and the force variation of the standard electrode insertion at low speed was significantly greater than the other two electrodes. For the same electrode, robot-assisted insertion presented significantly lower peak force and force variation than manual insertion for each type of electrode array. But there was no difference in the peak force and force variation between two-speed levels of robot assistance (P>0.05). Conclusions: The insertion force of the electrode array will be lower when a slim electrode array or robot technique is applied. Long electrode array might make manual insertion difficult or less precise. Robot assistance has advantage on force control during electrode array insertion.
Cochlea/surgery* ; Cochlear Implantation ; Cochlear Implants ; Electrodes, Implanted ; Humans ; Robotics

For cochlear implant training and robotic cochlear implant experiments, the design method of scalable scala tympani model was proposed. The mathematical model of the cochlea was used as the central curve of scala tympani channel. Referring to the clinical anatomy data, the contour of the scala tympani cross-section was approximated as an ellipse. The profile was placed along the central curve, and the angle was adjusted to determine the position and orientation of the profile in three dimensions such that the central curve passes through its center. The data was imported into Matlab to generate a three-dimensional mathematical model of scala tympani, which can be expanded by setting different scale factors. The virtual scala tympani model was generated in SolidWorks, and the 2:1 fully transparent scala tympani model were fabricated by 3D printing to replace the specimen for experiment.
Cochlea/surgery* ; Cochlear Implantation ; Cochlear Implants ; Robotics ; Scala Tympani/surgery*

Child ; Child, Preschool ; Cochlea ; surgery ; Cochlear Implantation ; methods ; Female ; Humans ; Infant ; Male ; Ossification, Heterotopic ; surgery

OBJECTIVE: To review the classification of cochlear modiolus deficiency and decision on surgical approach for above case,in order to provide mastery for cochlear implant (CI) indication. METHOD: Basing on temporal bone HRCT pre-operation, CI subjects with modiolus deficiency were defined as following groups: (1) deficiency caused by cochlear dysplasia (Mondini malformation); (2) deficiency caused by dysplasia of cochlear and vestibule (Common cavity malformation); (3) deficiency caused by absence of internal acoustic meatus fundus (IP-III malformation). Three types of surgical approach were utilized: type I, electrode array was introduced through facial recess, enlarged the round window, type II, opened the surface of chchlea, electrode array was introduced through facial recess, fenestration on posterior promontory and then inserted around lateral wall of inner-cochlear cavity. type III, electrode array was introduce through fenestration of lateral semicircular canal and then placed close to the bony wall of common cavity. RESULT: One hundred and sixty-six cochlear modiolus deficiency cases were identified into 3 groups as following: 135 Mondini malformation cases into group a, 18 common cavity malformation cases into group b, and 13 IP-III malformation cases into group c. Surgical approach: type I were used in 136 cases (123 Mondini cases and 13 IP-III cases), while approach type II in 12 cases (12 Mondini cases), and approach type III in 18 cases (18 common cavity cases). Income post-operation of CI: For group a (Mondini malformation), post-activation mean hearing threshold in sound field was 65 dB, speech recognition score is 95% (single finals test) and 25% (signal initials test), while it was 80 dB, 60% and 0 for group b (Conmon cavity malformation), and it was 55 dB, 100% and 45% for group c (IP-III malformation). CONCLUSION The income of speech recognition score for cochlear modiolus deficiency was relatively poor, group b was worst and group c was best, while group a moderate.
Cochlea ; abnormalities ; surgery ; Cochlear Implantation ; methods ; Cochlear Implants ; Ear ; Ear, Inner ; abnormalities ; Female ; Humans ; Male ; Postoperative Period ; Round Window, Ear ; surgery ; Semicircular Canals ; surgery ; Speech Perception ; Temporal Bone ; Vestibule, Labyrinth ; abnormalities

OBJECTIVE: To investigate cochlear implantation surgical techniques and postoperative results in patients with cochlear ossification. METHOD: Twenty-nine cochlear ossification patients with cochlear implantation in our department were retrospectively studied during 1997-2011. Preoperative imaging and electrophysiological assessment were done to classify the cochlear ossification of all the patients. Categories of auditory performance and speech intelligibility rating were detected to assess the outcome of cochlear implant postoperatively. RESULT: Among 29 cases with cochlear ossification, 19 cases were grade II, 4 cases were grade I, 4 cases were grade III, and 2 cases were apical turn ossification. Among 23 patients with cochlear ossification grade I and II, 17 cases were totally cochlear array insertion, and 6 cases were partial cochlear array insertion. Patients with cochlear ossification grade III were all partial cochlear array insertion. Most patients achieved good hearing and language ability after cochlear implantation. CONCLUSION Cochlear implantation can be successfully performed on the basis of systematic preoperative assessment and some patients can achieve good postoperative results in patients with cochlear ossification. Intraoperative electrical stimulation of the auditory evoked response provides a good method to assess the residual spiral nerve function.
Adolescent ; Adult ; Child ; Child, Preschool ; Cochlea ; pathology ; Cochlear Implantation ; methods ; Female ; Follow-Up Studies ; Hearing Loss, Sensorineural ; etiology ; surgery ; Humans ; Male ; Middle Aged ; Ossification, Heterotopic ; complications ; Retrospective Studies ; Treatment Outcome ; Young Adult

OBJECTIVE: To observe the change of auditory brainstem response (ABR) in hearing deprivation rat model induced by bilateral cochlears ablation at different time points. METHOD: Forty SD rats were randomly divided into four experiment groups including 2-week group, 4-week group, 6-week group, 8-week group and four control groups with 5 rats (n = 10) in each group. Then bilateral cochlears ablation was applied to experiment groups. The threshold value of ABR was measured at different time and latent period of each wave was compared. RESULT: The threshold of ABR in experiment group was elevated significantly. The latent period of each wave was pro longed significantly (P < 0.01). In experiment group, the threshold value of ABR in 2-week and 4-week group was significantly greater than that in 6-week group and 8-week group (P < 0.01). CONCLUSION Bilateral cochlears ablation surgery could elevate the threshold of ABR and latent period of each wave prolonged. The effect of hearing deprivation became apparent after surgery for 4 weeks.
Animals ; Auditory Threshold ; Cochlea ; physiopathology ; surgery ; Disease Models, Animal ; Evoked Potentials, Auditory, Brain Stem ; physiology ; Hearing Loss ; Male ; Rats ; Rats, Sprague-Dawley

OBJECTIVE: The purpose of this study is to report surgical skills for CI cases with modiolus ossification and to investigate the relation between post-operational electroneurophysilogical test result and speech recognition result. Further more, we also attempt to confirm indications for CI in this specific population. METHOD: Based on temporal bone HRCT, 7 subjects were identified as modiolus ossification from 101 cases with cochlear ossification. Modiolus ossification is confirmed by CT scan if CT value in modiolus reaches or exceeds 900 HU with the exception of congenital modiolus ossification or modiolus seal off. Electroneurophysiological test was conducted intra- and pos-operationally speech tests were applied for 7 subjects. RESULT: Normal impedance value was observed by intro-operational measurement in 7 subjects. EABR test was conducted and negtive response was observed in only 1 subject, while other 6 subjects were confirmed with atypical EABR waves which were observed in apical and middle turn region. Hearing threshold test (in sound field) was applied, no auditory response was recorded for the subject without EABR waveform, while hearing threshold in average for the other 6 subjects was 75 dB. Results of speech tests (Mandarin) were followed as 0 for the one without EABR wave, while 100% (simple finals test) and 30% (simple initials test) for the other 6 subjects. CONCLUSION Optimal multichannel CI surgery that inserting and locating electrode array spirally is very frequently interrupted by ossification,which was indentified with atypical EABR wave and relative poor speech recognition results, especially in modiolus ossification case. A post-operative negative EABR response may indicate surgical failure following cochlear implantation.
Adolescent ; Adult ; Child ; Child, Preschool ; Cochlea ; pathology ; Cochlear Implantation ; Evoked Potentials, Auditory, Brain Stem ; physiology ; Female ; Humans ; Infant ; Male ; Middle Aged ; Ossification, Heterotopic ; surgery ; Postoperative Period ; Young Adult