Objective: To analyze the temporal bone CT and inner ear magnetic resonance imaging characteristics of cochlear implant patients with no cochlear nerve display in the inner auditory canal under MRI. To retrospectively analyze the long-term hearing and speech rehabilitation effects of such patients after cochlear implant. And to analyze the correlation between the results of imaging examinations and the postoperative effects of cochlear implant patients with this type of cochlear nerve deficiency. Methods: A total of 88 children with cochlear nerve deficiency, who underwent cochlear implantation in Shandong Provincial ENT Hospital from May 2014 to October 2018, were enrolled. Patients with cochlear malformations were excluded,only the patients with cochlear nerve deficiency whose cochlear structure was normal and no cochlear nerve displayed in inner auditory canal under MRI were enrolled. There were 64 patients, including 4 bilaterally implanted, 68 ears in total, with an average age of (2.8±1.7) years (range 1-6 years) at the time of implantation. The implanted product was Cochlear, including 24RECA and 512 models. All patients underwent inner ear magnetic resonance imaging and temporal bone CT scan before operation. Auditory speech function assessments were performed at 12 months, 24 months, and 36 months after surgery, including categories of auditory performance (CAP), speech intelligibility rating (SIR) and hearing aid threshold test. The imaging evaluation content included the width of the cochlear nerve canal of temporal bone CT, the width of the internal auditory canal, the width of the auditory nerve at the cerebellopontine angle of the inner ear MRI, and the ratio of the facial nerve to the width of the auditory nerve at the cerebellopontine angle. The correlations between the results of postoperative hearing aid hearing threshold, CAP, SIR and imaging results were analyzed. Results: Among the 64 cases of cochlear nerve not shown under MRI, 56 ears with CT data showed that the width of the cochlear nerve canal in temporal bone CT was (0.72±0.30) mm (mean±standard deviation, the same below), and the width of the internal auditory canal was (4.07±1.10) mm; 66 ears with MRI data showed that the diameter of the auditory nerve at the cerebellopontine angle of the inner ear MRI was (1.58±0.27) mm, the diameter of the facial nerve was (1.57±0.27) mm, and the ratio of the diameter of the facial nerve to the auditory nerve was (1.02±0.23). The average hearing thresholds at 12, 24, and 36 months after surgery were (46.8±2.5) dB HL, (40.7±0.8) dB HL, and (36.8±1.5) dB HL, respectively. The preoperative and postoperative CAP scores at 12, 24 and 36 months were (1.0±1.0), (3.8±1.4), (4.5±1.4) and (5.1±0.7) points, respectively. The preoperative and postoperative SIR scores at 12, 24, and 36 months were (1.1±0.3), (1.9±0.9), (2.5±0.9), and (2.9±0.6) points, respectively. The hearing threshold at 24 months after surgery was negatively correlated with the width of the internal auditory canal of temporal bone CT (r=-0.349, P=0.037), and the hearing threshold at 36 months after surgery was positively correlated with the ratio of the diameter of the facial nerve to the auditory nerve at the cerebellopontine angle of the inner ear MRI (r=0.740, P=0.001). Conclusions: Children with cochlear implants whose cochlear nerves are not shown on MRI can benefit from cochlear implantation, and their speech and auditory functions can improve significantly after surgery. The width of the internal auditory canal in the temporal bone CT and the ratio of the diameter of the facial nerve to the auditory nerve at the cerebellopontine angle of the inner ear MRI may be related to the long-term hearing threshold after surgery.
Child ; Child, Preschool ; Cochlear Implantation ; Cochlear Implants ; Cochlear Nerve/diagnostic imaging* ; Hearing Loss, Sensorineural/surgery* ; Humans ; Infant ; Magnetic Resonance Imaging ; Prognosis ; Retrospective Studies ; Speech Intelligibility

Adolescent ; Child ; Child, Preschool ; Chorda Tympani Nerve ; diagnostic imaging ; surgery ; Cochlear Implantation ; methods ; Female ; Humans ; Male ; Radiography ; Young Adult

OBJECTIVE: To observe normal and abnormal findings of foramina within internal auditory canal (IAC) fundus with Virtual Endoscopy of multisection helical Computed Tomography. METHOD: CT scanning of temporal bone was undergone in 25 volunteers (50 ears) in the normal group, in 8 cases (13 ears) with foramina hypoplasia within IAC fundus which were shown on CT and MRI images. CT virtual endoscopy (CTVE) findings were observed in the normal and abnormal groups. The lower threshold value was 900-1200 HU, the upper value was 3,071 HU in CTVE definitions. RESULT: The shape and position of foramina within IAC fundus were shown on the CTVE image, 50 foramina within IAC fundus were shown in all normal cases. In abnormal group, 9 ears were shown as IAC fundus disorder and foramina absent, only 1 foramina was shown in 1 ear, 2 foramen in 4 ears, 3 foramen in 2 ears, 4 foramen in 2 ears; Abnormal shape of cochlear nerve foramina was seen in 4 ears. Other malformations were also shown, including IAC malformations in 3 ears and inner ear malformations in 8 ears. CONCLUSION CTVE is useful to show the shape and position of normal foramina and pathological changes in the patients with foramina hypoplasia within IAC fundus.
Adolescent ; Adult ; Case-Control Studies ; Child ; Child, Preschool ; Cochlear Nerve ; abnormalities ; diagnostic imaging ; Ear Canal ; abnormalities ; diagnostic imaging ; Ear, Inner ; abnormalities ; diagnostic imaging ; Female ; Hearing Loss, Sensorineural ; congenital ; diagnostic imaging ; Humans ; Male ; Middle Aged ; Tomography, Spiral Computed ; methods ; Young Adult

PURPOSE: Auditory nerve injury is one of the most common nerve injury complications of skull base fractures. However, there is currently a lack of auxiliary examination methods for its direct diagnosis. The purpose of this study was to find a more efficient and accurate means of diagnosis for auditory nerve injury. METHODS: Through retrospectively analyzing the results of brainstem auditory evoked potential (BAEP) and high-resolution CT (HRCT) in 37 patients with hearing impairment following trauma from January 1, 2018 to July 31, 2020, the role of the two inspection methods in the diagnosis of auditory nerve injury was studied. Inclusion criteria were patient had a clear history of trauma and unilateral hearing impairment after trauma; while exclusion criteria were: (1) severe patient with a Glasgow coma scale score ≤5 because these patients were classified as severe head injury and admitted to the intensive care unit, (2) patient in the subacute stage admitted 72 h after trauma, and (3) patient with prior hearing impairment before trauma. According to Goodman's classification of hearing impairment, the patients were divided into low/medium/severe injury groups. In addition, patients were divided into HRCT-positive and negative groups for further investigation with their BAEP results. The positive rates of BEAP for each group were observed, and the results were analyzed by Chi-square test (p < 0.05, regarded as statistical difference). RESULTS: A total of 37 patients were included, including 21 males and 16 females. All of them were hospitalized patients with GCS score of 6-15 at the time of admission. The BAEP positive rate in the medium and severe injury group was 100%, which was significantly higher than that in the low injury group (27.27%) (p < 0.01). The rate of BEAP positivity was significantly higher in the HRCT-positive group (20/30, 66.7%) than in the HRCT-negative group (1/7, 14.3%) (p < 0.05). Twenty patients (54.05%) were both positive for BEAP and HRCT test, and considered to have auditory nerve damage. Six patients (16.22%) were both negative for BEAP and HRCT test, and 10 patients (27.03%) were BAEP-negative but HRCT-positive: all the 16 patients were considered as non-neurological injury. The rest 1 case (2.70%) was BAEP-positive but HRCT-negative, which we speculate may have auditory nerve concussion. CONCLUSION By way of BAEP combining with skull base HRCT, we may improve the accuracy of the diagnosis of auditory nerve injury. Such a diagnostic strategy may be beneficial to guiding treatment plans and evaluating prognosis.
Cochlear Nerve ; Evoked Potentials, Auditory, Brain Stem/physiology* ; Female ; Hearing Loss ; Humans ; Male ; Retrospective Studies ; Skull Base/diagnostic imaging* ; Tomography, X-Ray Computed