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*

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

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

Animals ; Auditory Threshold ; Cochlea ; physiology ; Ear, Middle ; surgery ; Evoked Potentials, Auditory, Brain Stem ; Female ; Male ; Rats

Pneumolabyrinth or pneumocochlea is an uncommon condition in which the vestibule or cochlea is filled with air. Although there have been several reports about pneumolabyrinth after stapes surgery, it is rarely found in temporal bone fractures. The presence of air inside the inner ear is a definite proof of a pathological connection between the inner ear and the air-filled mastoid or middle ear cavities. We encountered a rare case of a 45-years-old male with a pneumolabyrinth that resulted from a blunt head trauma. A pneumolabyrinth was resolved spontaneously.
Cochlea ; Craniocerebral Trauma ; Ear, Inner ; Ear, Middle ; Fractures, Closed ; Humans ; Male ; Mastoid ; Stapes Surgery ; Temporal Bone*

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*

OBJECTIVETo investigate the related parameters of the temporal bone structure for determining the position of implanting electrode into the scala tympani in cochlear implantation surgery through the facial recess and epitympanum approach.

METHODSIn a surgical simulation experiment, 20 human temporal bones were studied and measured to determine the related parameters of the temporal bone structure.

RESULTSThe distance 5.91∓0.29 mm between the short process of the incus and the round window niche, 2.11∓0.18 mm between the stapes and the round window niche, 6.70∓0.19 mm between the facial nerve in the perpendicular paragraph and the round window niche, 2.22∓0.21 mm from the pyramidal eminence to the round window, and 2.16∓0.14 mm between the stapes and the round window. The minimal distance between the implanting electrode and the vestibular window was 2.12∓0.19 mm. The distance between the cochleariform process and the round window niche was 3.79∓0.17 mm. The position of the cochlear electrode array insertion into the second cochlear turn was 2.25∓0.13 mm under the stapes. The location of the cochlear electrode array insertion into the second cochlear turn was 2.28∓0.20 mm inferior to the pyramidal eminence.

CONCLUSIONThese parameters provide a reference value to determine the different positions of cochlear electrode array insertion into the scale tympani in different patients.

Adult ; Cochlea ; anatomy & histology ; surgery ; Cochlear Implantation ; Cochlear Implants ; Ear, Middle ; anatomy & histology ; surgery ; Female ; Humans ; Male ; Round Window, Ear ; anatomy & histology ; surgery ; Scala Tympani ; anatomy & histology ; 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

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