Adult progressive sensorineural hearing loss: is preoperative imaging necessary before cochlear implantation?

Preoperative Imaging in Cochlear Implants

OBJECTIVE

To determine the utility of computed tomography (CT) and magnetic resonance imaging (MRI) in cochlear implant candidates.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral hospital.

PATIENTS

A total of 207 cochlear implanted patients with CT and/or MRI.

INTERVENTIONS

N/A.

MAIN OUTCOME MEASURES

Age versus abnormal radiologic findings, imaging abnormality versus postoperative outcomes, postoperative outcomes versus electrode design, Cambridge Cochlear Implant Protocol (CCIP) status for imaging abnormalities, sensitivity and specificity of CT and MRI for round-window/cochlear occlusion, and MRI for incomplete partitions.

RESULTS

A total of 207 patients with CT, MRI, or both were reviewed retrospectively. Less than half (15.5%) of CT scans had findings that might affect surgical intervention compared with 5.9% of MRI. No significant difference was found between children and adults for relevant imaging abnormalities (grade 4 or higher) with either CT (p = 0.931) or MRI (p = 0.606). CCIP status correlated with cochlear abnormalities (p = 0.040); however, only 46.2% of radiographic abnormalities on CT would be identified by these criteria. For detecting cochlear occlusion requiring surgical intervention, the sensitivity and specificity for CT were 40% (4 of 10; 95% confidence interval [CI], 12.16-73.76) and 95.73% (95% CI, 91.40-98.27), respectively. For MRI, the sensitivity and specificity were 33.33% (1 of 3; 95% CI, 0.84-90.57) and 96.97% (63 of 65; 95% CI, 89.32-99.63), respectively. There was no difference for postoperative AzBio scores for higher-grade imaging abnormalities (p = 0.6012) or for electrode designs (p = 0.3699).

CONCLUSIONS

Significant radiographic abnormalities were relatively uncommon in cochlear implant patients on either CT or MRI at our single-center institution. If present, abnormal imaging findings rarely translated to management changes. CCIP status does not reliably predict which patients are likely to have abnormalities. Both MRI and CT have low sensitivity for round-window or cochlear occlusion, but detection likely leads to changes in surgical management.

Ultra-low-dose CBCT scan: rational map for ear surgery

PURPOSE

This study will evaluate the clinical quality and usability of peripheral image data from the temporal bone area obtained using a sinonasal ultra-low-dose (ULD) cone-beam computed tomography (CBCT) scan and compare them to those obtained using a high-resolution (HR) CBCT.

METHODS

The population consisted of 66 anatomical sites (ears of 33 subjects) imaged using two modalities: an HR CBCT (Scanora 3Dx scanner; Soredex, Tuusula, Finland) and a ULD CBCT (Promax 3D Mid scanner; Plandent, Helsinki, Finland). The image quality (IQ) for every anatomical site in each image was rated using a Likert scale from 0 to 5.

RESULTS

The quality of ULD CBCT scans was clinically sufficient in over 95% of the assessed images of the sigmoid sinus, jugular bulb, epitympanum and mastoid antrum as well as external acoustic meatus (all p > 0.05 compared to HR CBCT). The IQ was clinically sufficient in 75-94% of the assessed images of the scutum, mastoid segment of the facial nerve, cochlea and semicircular canals (all p < 0.05 compared to HR CBCT). The overall IQ of the HR CBCT scans was good or excellent.

CONCLUSION

CBCT imaging and the data at image margins are underutilized. CBCT can produce excellent structural resolution with conventional imaging parameters, even with off-focus images. Using ultra-low doses of radiation, the produced IQ is clinically sufficient. We encourage ear surgeons to check the patients' imaging history and to consider the use of imaging modalities that involve lower radiation doses especially when conducting repetitive investigations and with children.

Bilateral Cochlear Implantations in Temporal Bone Fracture: A Viable Treatment Option

OBJECTIVES/HYPOTHESIS

Although it is surgically more challenging, patients with bilateral temporal bone fractures (TBFs) are potential candidates for successful bilateral cochlear implantation (CI). This study aimed to investigate the feasibility of bilateral implantation in patients with sustained bilateral TBFs.

STUDY DESIGN

Retrospective database study.

METHODS

Seven patients with bilateral cochlear implants who were diagnosed with TBFs were included in this study. Preoperative radiological and audiological evaluations were performed. The outcomes of the CI were also investigated.

RESULTS

Hearing levels were restored to the mild-moderate range (<40 dB) for nearly all patients and they reported an improved quality of life.

CONCLUSIONS

CI in patients with TBF is safe and offers a solution for the restoration of hearing in a population who may experience sudden bilateral deafness. However, preoperative confirmation of intact auditory nerves and patent cochlea is essential to maximize the success of CI in this population.

LEVEL OF EVIDENCE

4 Laryngoscope, 2021.

Adult Onset Bilateral Cochlear Nerve Atrophy and Cochlear Implantation: A Case Report and Review of the Literature

OBJECTIVE

To describe a case of idiopathic bilateral cochlear nerve atrophy acquired in adulthood.

PATIENT

A 75-year-old male with acquired bilateral cochlear nerve atrophy.

INTERVENTION(S)

Unilateral cochlear implantation.

MAIN OUTCOME AND RESULTS

Description of a patient with acquired bilateral cochlear nerve atrophy diagnosed at the age of 75. The patient had normal hearing and no communication deficits until the age of 66. At this point, the patient demonstrated a slight asymmetric hearing loss, which progressed to severe sensorineural hearing loss. Due to the resulting communication deficit, cochlear device implantation candidacy was pursued. Pre-operative magnetic resonance imaging (MRI) showed severe atrophy versus absence of the cochlear nerves bilaterally. After careful counseling regarding the expected communication outcomes given the MRI findings, the patient underwent left-sided cochlear implantation. The patient gained sound awareness, but no additional communication benefit compared to pre-operative baseline abilities.

CONCLUSION

Cochlear nerve deficiency is a known finding in certain cases of congenital and acquired hearing loss, but no cases of idiopathic adult-onset bilateral nerve atrophy have been reported. Without MR imaging, the clinically significant finding would not have been identified. Thus, MRI is advantageous when compared with other imaging modalities in patients with progressive sensorineural hearing loss and enables improved patient counseling regarding expected auditory and communication outcomes.

Utility and value of pre-operative CT and MRI for cochlear implantation in the elderly

PURPOSE

To determine the utility and value of pre-operative imaging among the elderly population ≥70 y.o. with bilateral progressive sensorineural hearing loss undergoing cochlear implantation.

MATERIALS AND METHODS

A retrospective, cross-sectional review was performed at a tertiary referral center between 2010 and 2018 including patients ≥70 y.o. with bilateral presbycusis who underwent preoperative imaging and cochlear implantation. Primary outcome was whether pre-operative imaging changed the surgeon's surgical plan such as side of implant or abort procedure entirely. Patient characteristics including age, sex, side of implant, imaging modality, whether imaging changed surgical plan, and surgical complications were reviewed. One-way analysis of variance with post-hoc tests using the Bonferroni and Fisher's exact test were used to examine differences between groups. Secondary outcome was cost of preoperative imaging.

RESULTS

One hundred thirty-three patients (mean age 79.38 [5.51 SD]) who underwent a total of 142 surgical cases and 147 total scans. There were 92, 27, and 14 patients who underwent CT, MRI, or both, respectfully (n=133). Of the 142 implants that were placed, preoperative imaging did not reveal a contraindication to placing implant on one side over another. Total cost of imaging was $29,694. Estimated cost if 20% of cochlear implant eligible patients ≥70 y.o. underwent imaging is $7,763,490.

CONCLUSION

Decreasing unnecessary preoperative imaging can potentially decrease cost in cochlear implantation. In this sample, preoperative imaging did not affect the surgeon's choice of which side to operate on. However, imaging may provide an anatomic roadmap and contribute to either surgical confidence or caution. With the increasing amount of cochlear implant eligible elderly adults, preoperative imaging needs to be more clearly defined in this unique population.

Diagnostic Protocol for Detecting Otosclerosis on High-Resolution Temporal Bone CT

OBJECTIVES

To present a systematic checklist to improve diagnosing otosclerosis (OS) on high-resolution computed tomography (HRCT) of the temporal bones and review this protocol's efficacy in diagnosing OS on HRCT.

METHODS

A retrospective case series was performed at a University Referral Hospital in urban Chicago, Illinois. High-resolution computed tomographies of the temporal bone were reviewed including 17 ears in the test group with surgically confirmed OS and 21 ears in the control group surgically confirmed to not have OS. Preoperative HRCTs were evaluated by a single neuroradiologist using a systematic protocol created to assist in diagnosing OS. This looked for radiolucency at the fissula ante fenestram and pericochlear region, and new bone formation around the oval and round windows.

RESULTS

The radiologist accurately diagnosed OS in all 17 test group ears and ruled out OS in all 21 control group ears using the protocol. All 17 test ears were read to have lucency at the fissula ante fenestram, 9 (53.0%) to have new bone formation, and 8 (47.1%) to have cochlear lucency. The radiologist was more confident in diagnosing OS when cochlear lucency was present with the fissula ante fenestram lucency.

CONCLUSIONS

This HRCT checklist is a highly accurate tool for evaluating the presence of OS when images are reviewed in the systematic fashion described. Imaging prior to surgery aids in counseling patients, preparing surgically, and excluding other pathologies.

3 T - MRI improves intrameatal cranial nerve detection in CI-candidates

BACKGROUND

Cochlear implantation meanwhile is a well established standard therapy in different forms of hearing loss in most ages. Clear depiction of the cochleovestibular anatomy and the cochlear nerve are very important for indication and effectiveness of cochlear implantation. Aim/objectives: Therefore the question raises whether Highfield MRI improves precision of preoperative diagnostic imaging especially along the the intrameatal portion of the vestibulocochlear nerve.

METHODS

We analyzed the MRI scans of 216 temporal bones from 2007 until 2017. In all patients, CI was planned. We compared examinations using 1.5 and 3.0 T MR systems under the aspect of intracanalicular detection of the facial nerve, cochlear nerve, and the vestibular branches.

RESULTS

3 T-MRI was able to detect the cochlear nerve in all cases, a very important criterion for CI-indication. 3 T-MRI was also superior in the detection of facial nerve and especially the vestibular branches.

CONCLUSION AND SIGNIFICANCE

The most effective preoperative examination of CI-candidates is the combination of 3 T MRI and multislice HR-CT of the temporal bone.

Which imaging modality in cochlear implant candidates?

PURPOSE

There is no guideline or consensus on preoperative radiologic imaging modality despite the fact that it has a vital importance in appropriate candidacy selection of cochlear implantation. We aimed to find out the role of high-resolution computed tomography (HRCT) and magnetic resonance imaging (MRI) on surgical planning, intraoperative technique in cochlear implant candidates.

METHODS

The clinical charts, imagings, and operative reports of patients who underwent cochlear implant surgery at a tertiary institution were retrospectively examined.

RESULTS

611 patients (503 children and 108 adult) were enrolled into the study. We found 11 different pathologies in MRI which could not be seen in HRCT. However, we decided the side of surgery according to MRI in only three of them in which the pathology was cochlear nerve hypoplasia. Two patients with cochlear nerve hypoplasia were children with prelingual deafness and one was adult with perilingual deafness. Moreover, we changed the surgical planning of side according to both imaging modalities in nine patients. Seven of them were children and two were adult. One of these adults had cochlear anomaly, and another had bilateral temporal bone fracture.

CONCLUSIONS

We suggest both imaging modalities in pediatric candidates. However, in adults, we think that superiority of either imaging modalities is still contradictive. We had only three adult patients and the decision of the side of surgery was made according to MRI in one of them and to both imaging modalities in the other two adults.

Cochlear implantation in a subject with a narrow facial recess: Importance of preoperative radiological findings

OBJECTIVE

This case report aims to emphasize the importance of preoperative computed tomography to evaluate the anatomy of the facial recess (FR) in order to prevent complications during cochlear implantation (CI) and to discuss alternative surgical approaches for the management of a narrow FR. Failure to notice this anomaly may result in facial nerve (FN) injury or inability to complete CI.

CASE PRESENTATION

A 50-year-old female with bilateral sensorineural hearing loss presented for CI. High-resolution CT (HRCT) demonstrated a narrow FR; specifically the space between the vertical segment of the FN and external auditory canal (EAC) was narrow. A section of the EAC was removed to obtain adequate exposure and was repaired with a cartilage graft following CI.

CONCLUSION

CI surgery may be difficult in patients with a narrow FR. Such surgical difficulty could be avoided if cochlear implant surgeons have adequate preoperative radiological imaging to evaluate the anatomy of the temporal bone. HRCT is the only modality that can detect this abnormality preoperatively. If the surgeon identifies this abnormality on preoperative HRCT, an alternative surgical technique could be used.

Utility of preoperative computed tomography and magnetic resonance imaging in adult and pediatric cochlear implant candidates

OBJECTIVES/HYPOTHESIS

Determine the utility of preoperative imaging in adult and pediatric cochlear implant candidates.

STUDY DESIGN

Retrospective chart review.

METHODS

Medical records of 101 consecutive adult and 20 consecutive pediatric patients who underwent 137 cochlear implantation (CI) procedures at a single institution were reviewed.

RESULTS

Computed tomography (CT) was obtained preoperatively in 110 (90.9%) patients, preoperative magnetic resonance imaging (MRI) was obtained in 102 (84.3%) patients, and both were obtained in 94 (77.7%) patients. MRI revealed one acoustic neuroma and two meningiomas, which affected surgical planning for three (2.2%) procedures. MRI identified enlarged vestibular aqueduct (EVA) in 2.0% of adult patients. CT demonstrated middle ear disease in four (3.3%) patients. CT was useful in indicating round window and cochlear patency in three (2.2%) patients with cochlear otosclerosis. Twenty pediatric patients underwent 27 CI procedures. Preoperative CT in the pediatric cohort demonstrated five (25%) dysplastic cochleae, three (15%) dysplastic vestibules and/or semicircular canals, and three (15%) EVAs. In one patient, CT demonstrated a duplicated right internal auditory canal (IAC) and hypoplastic left IAC; MRI confirmed hypoplastic cochlear nerves.

CONCLUSIONS

Preoperative MRI can demonstrate retrocochlear pathology, cochlear patency, and EVA in adults being evaluated for cochlear implantation. CT may provide additional information in patients with chronic otitis media or otosclerosis. However, in postlingually deafened adults without conductive or asymmetrical hearing loss, imaging is unlikely to affect surgical decision making. Both CT and MRI can identify anomalies in pediatric patients. MRI does not offer substantial benefit over CT for routine evaluation of pediatric inner ear and temporal bone anatomy.

LEVEL OF EVIDENCE

4 Laryngoscope, 126:1440-1445, 2016.

Favorable proliferation and differentiation capabilities of neural precursor cells derived from rat cochlear nucleus

NSCs/NPCs could be used for Sensorineural hearing loss treatment, because of the extensive capacity for self-renewal and pluripotency. In order to isolate and identify neural precursor cells (NPCs), we established a strategy to isolate and cultivate NPCs. Immunohistochemistry, immunofluorescence, Western blotting, and electron microscopy were used to characterize the cells and compare their differentiation patterns with those of olfactory bulb and olfactory epithelium NPCs. Furthermore, NPCs from the cochlear nucleus were sustained good cell viability and cloning efficiency after cryopreservation and thawing. Finally, high capacity to differentiate into astrocytes, oligodendrocytes, and neurons of NPCs was found. In conclusion, NPCs isolated from the cochlear nucleus can proliferate and differentiate into functional neurons, which offers a potential strategy for sensorineural hearing loss treatment. In addition, the storage method developed here will benefit further exploration of NPCs.