Facial nerve aberrations encountered during cochlear implantation

Bifid Intratemporal facial nerves in an adult without other congenital anomalies

Objective

To describe a case of bifid intratemporal facial nerves without associated middle or inner ear abnormalities encountered on computed tomography (CT) imaging during preoperative preparation for unilateral cochlear implant placement in an adult male with profound sensorineural hearing loss (SNHL).

Methods

A rare case of bilateral bifid intratemporal facial nerves in an adult male is presented. The finding's impact on approach to safe cochlear implantation is discussed.

Results

Bifurcation of the intratemporal facial nerve is rarely seen and is usually associated with congenital middle or inner ear anomalies. A unique case of bilateral bifid intratemporal facial nerves without other middle or inner ear abnormalities was encountered incidentally on CT imaging during preparation for unilateral cochlear implant placement in an adult male with profound SNHL. The nerve was bifid along the mastoid segment with a nerve branch traversing through the facial recess precluding safe traditional approach to cochlear implant placement. Accessory stylomastoid foramina were noted bilaterally. Unilateral subtotal petrosectomy was performed with successful implantation and excellent hearing outcome. No additional clinical or radiographic otologic abnormalities were noted.

Conclusion

Abnormal bifurcation of the facial nerve may occur in adults without other middle or inner ear anomalies. This case highlights the importance of independent imaging review by the surgeon and vigilance to potential rare anatomic aberrations of the facial nerve during cochlear implantation.

Level of Evidence

IV.

Association of Ear Anomalies and Hearing Loss Among Children With 22q11.2 Deletion Syndrome

OBJECTIVE

To identify inner and middle ear anomalies in children with 22q11.2 deletion syndrome (22q11DS) and determine associations with hearing thresholds.

STUDY DESIGN

Retrospective study.

SETTING

Two tertiary care academic centers.

METHODS

Children presenting with 22q11DS between 2010 and 2020 were included. Temporal bone imaging with computed tomography or magnetic resonance imaging was reviewed by 2 neuroradiologists.

RESULTS

Twenty-two patients (12 female, 10 male) were identified. Forty-four ears were evaluated on imaging. There were 15 (34%) ears with abnormal semicircular canals, 14 (32%) with abnormal vestibules, 8 (18%) with abnormal ossicles, 6 (14%) with enlarged vestibular aqueducts, 4 (9.1%) with abnormal facial nerve canals, and 4 (9.1%) with cochlear anomalies. There were 25 ears with imaging and audiometric data. The median pure tone average (PTA) for ears with any structural abnormality was 41.0 dB, as compared with 28.5 dB for ears without any structural abnormality (P = .21). Of 23 ears with normal imaging, 6 (26%) had hearing loss in comparison with 13 (62%) of 21 ears with abnormalities (P = .02). Total number of anomalies per ear was positively correlated with PTA (Pearson correlation coefficient, R = 0.479, P = .01). PTA was significantly higher in patients with facial nerve canal anomalies (P = .002), vestibular aqueduct anomalies (P = .05), and vestibule anomalies (P = .02).

CONCLUSIONS

Semicircular canal, ossicular, vestibular aqueduct, and vestibular anomalies were detected in children with 22q11DS, especially in the setting of hearing loss. Careful evaluation of anatomic anomalies is needed prior to surgical intervention in these patients.

Systematic review of cochlear implantation in patients with inner ear malformations

OBJECTIVES

To evaluate the outcomes of cochlear implantation in patients with severe to profound sensorineural hearing loss due to inner ear malformations (IEMs) when compared to patients without IEMs. We discussed audiological outcomes such as open-set testing, closed-set testing, CAP score, and SIR score as well as postoperative outcomes such as cerebrospinal fluid gusher and incomplete insertion rate associated with cochlear implantation in individuals with IEMs.

DATA SOURCES

PubMed, Science Direct, Web of Science, Scopus, and EMBASE databases.

REVIEW METHODS

After screening a total of 222 studies, twelve eligible original articles were included in the review to analyze the speech and hearing outcomes of implanted patients with IEMs. Five reviewers independently screened, selected, and extracted data. The "Tool to Assess Risk of Bias in Cohort Studies" published by the CLARITY group was used to perform quality assessment on eligible studies. Systematic review registration number: CRD42021237489.

RESULTS

IEMs are more likely to be associated with abnormal position of the facial nerve, raising the risk of intraoperative complications. These patients may benefit from cochlear implantation, but audiological outcomes may also be less favorable than in individuals without IEMs. Furthermore, due to the risk of cerebrospinal fluid gusher, incomplete insertion of electrodes, and postoperative facial nerve stimulation, surgeons can employ precautionary measures such as preoperative imaging and proper counseling. Postoperative imaging is suggested to be beneficial in ensuring proper electrode placement.

CONCLUSIONS

Cochlear implants (CIs) have the potential to provide auditory rehabilitation to individuals with IEMs. Precise classification of the malformation, preoperative imaging and anatomical mapping, appropriate electrode selection, intra-operative techniques, and postoperative imaging are recommended in this population.

Effects of Age on Delayed Facial Palsy After Otologic Surgery: A Systematic Review and Meta-Analysis

OBJECTIVES

To report 4 cases of delayed facial palsy (DFP) after pediatric middle ear (ME) surgery and systematically review and analyze the associated literature to evaluate the effects of age on DFP etiology, management, and prognosis.

METHODS

Systematic review of PubMed, Cochrane Library, and Embase for articles related to DFP after cochlear implantation (CI) was performed. These articles were assessed for level of evidence, methodological limitations, and number of cases. Meta-analysis was performed to assess the effects of age on DFP incidence. Furthermore, a comprehensive list of all pediatric DFP cases after otologic surgery was assembled through a multi-institutional retrospective review and systematic review of the literature.

RESULTS

Twenty-nine articles fit the criteria for inclusion in the meta-analysis. The incidence of DFP after CI was 0.23% and 1.01% for pediatric and adult cases, respectively. This difference was statistically significant (P < .001, odds ratio 4.36). Twenty-three cases, adding to the 4 presented herein, were suitable for a comprehensive list. The mean age was 6.9 years. Average postoperative day of paresis onset was 5.4, with an average maximum House-Brackmann grade of 3.5. All patients obtained full facial recovery after an average of 23.5 days.

CONCLUSIONS

The systematic review demonstrates that DFP after pediatric CI is rare and occurs at a significantly lower rate than in adults, further supporting the viral reactivation hypothesis of DFP. The prognosis for pediatric DFP after otologic surgery is excellent, with a high rate of full recovery in a short time frame. However, steroid administration can be considered.

LEVEL OF EVIDENCE

IIa.

Combined Endoscopic/Microscopic Cochlear Implantation Through the Oval Window

Standard round window (RW) cochlear implantation is a well-described technique. Implantation might be difficult in patients with inner and middle ear anomalies, in some cases because of not achieving adequate exposure to the RW, with a related higher risk of complications such as facial nerve injury. It is proposed a combined microscopic/endoscopic oval window approach in a 63 year old man affected by bilateral Menière disease, with bilateral severe sensorineural hearing loss, speech discrimination score for bysillabic words under 40% and a hidden RW by anomalous facial nerve course. All electrodes entered the cochlear with good freefield thresholds and auditory ability results. A partial marginalis nerve palsy occurred at the second postoperative day and completely reversed at 2 months from surgery. Endoscopicassisted oval window cochlear implantation may be a safe alternative surgical technique in cases where surgeons are not able to access RW.

Radiological classification of the mastoid portion of the facial nerve: impact on the surgical accessibility of the round window in cochlear implantation

BACKGROUND

Mastoid portion of the facial nerve plays an important role in the round window approach of cochlear implantation.

OBJECTIVES

This study aimed to predict the anterior displacement of the mastoid portion of the facial nerve in the preoperative HRCT coronal cuts. We also aimed to detect the implication of anterior displacement of MPFN on the R.W. accessibility through the posterior tympanotomy during cochlear implantation.

MATERIALS AND METHODS

It was a retrospective observational cohort study in tertiary referral hospitals. We included 246 pediatric patients who underwent cochlear implantation due to bilateral severe to profound SNHL through a posterior tympanotomy approach.

RESULTS

Type I MPFN was present in 84 cases, type II MPFN was present in 149 patients, and type III MPFN was present in 13 cases. R.W. was inaccessible in 3 cases with MPFN type II and in 11 subjects with MPFN type III. There was a statistically significant difference regarding the R.W. accessibility between the three types of MPFN (p-value <.05). There was a strong statistically significant correlation between R.W. accessibility and the radiological type of the MPFN.

CONCLUSION

Mandour radiological classification of the mastoid portion of the facial nerve in the preoperative HRCT coronal offers an easily applicable method to detect the anterior displacement of the facial nerve by using easy and well-known landmarks. This classification can also predict R.W. accessibility through posterior tympanotomy during cochlear implantation with 97.97% accuracy.

Internal auditory canal hypoplasia associated with bilateral vestibulocochlear nerve aplasia and deviant facial nerve course: A case report and MRI findings

The evaluation of internal auditory canals and cochlea has gained significant importance due to the increasing number of cochlear implantations worldwide. This region's anatomical study is essential for cochlear implant surgery using magnetic resonance imaging as the method of choice. We report a case of a 6-year-old male patient diagnosed with a rare bilateral malformation of the internal auditory canals associated with an aberrant course of the facial nerve and vestibulocochlear nerve aplasia. This report raises the importance of identifying this rare malformation for appropriate management and reinforces awareness of possible complications.

Audiological and Surgical Outcomes of Pediatric Cochlear Implantation in Mondini's Dysplasia: Our Experience

OBJECTIVES

Aim of present study is to compare audiological and surgical outcomes in prelingual deaf children with Mondini's dysplasia (MD) and those with normal inner ear anatomy.

MATERIALS AND METHODS

Retrospective data was collected from Jan 2008 to Dec 2016. Children with bony IEM other than MD, syndromic association, multiple disabilities, those lost to follow up, and perilingual or postlingual deafness were excluded from study. Audiological outcomes for auditory perception (CAP score) and speech intelligibility (SIR score) was noted for a follow up period of 1 year.

RESULTS

Mean age at implantation was 2.8 years (Range of 2 to 6 years). 2 patients had intraoperative CSF ooze which was controlled intraoperatively by conservative measures. Post operative facial nerve function was normal in all patients. None of the patient in either group had any complications at one year of follow up period. There was statistically significant improvement in CAP - SIR score in Group A at 6 - 12 months compared to pretreatment. There was no statistically significant difference between the 2 groups in terms of CAP - SIR score at 6 - 12 months.

CONCLUSION

The study stresses the fact that cochlear implantation can be safely performed in children with MD although there is a risk of intraoperative CSF leak which can be controlled intraoperatively. Cochlear implantation in children with MD has good surgical, auditory and speech outcomes at par with children with normal bony inner ear anatomy.

Cochlear implant surgery through oval window: A novel approach in a child with facial nerve aberration

Cochlear implantation is safe for simple case presentations. However, facial nerve (FN) aberrations may impede insertion of the electrode through a round window and increase the risk of iatrogenic FN injury. We developed a novel method of cochlear implantation, a present the case of a child with FN aberrations. Inferior displacement of a horizontal segment of FN lay on the surface of th e promontory, obscuring the round window. The oval window was used and the electrode successfully inserted. No postoperative complications occurred, and significant improvement in speech perception was achieved. This novel approach is suitable for patients with FN aberrations.

A Novel Classification: Anomalous Routes of the Facial Nerve in Relation to Inner Ear Malformations

OBJECTIVES/HYPOTHESIS

The objective of this study was to classify anomalous facial nerve (FN) routes and to determine their association with inner ear malformations (IEMs).

STUDY DESIGN

Retrospective cross sectional study.

METHODS

The computed tomography images of 519 patients (796 ears) with IEMs were retrospectively evaluated, and the abnormal routes of the FN were classified as: Meatal segment: type 1, normal internal auditory canal (IAC); type 2, narrow IAC; type 3, facial canal (FC) only; type 4: separate FC/duplicated IAC. Labyrinthine segment (LS): type 1, normal; type 2a/b/c, mild/moderate/severe anterior displacement; type 3, superior displacement; type 4: straight LS. Tympanic segment (TS): type 1, normal; type 2, superiorly displaced TS; type 3, TS at the oval window; type 4: TS inferior to the oval window; type 5: unclassified. Mastoid segment: type 1, normal facial recess (FR)/normal mastoid segment; type 2: narrow FR; type 3, unclassified.

RESULTS

In meatal segment classification, a narrow IAC was common in ears with cochlear hypoplasia (CH) (76.1%), and only FC was common in ears with severe IEMs (62.7%) such as Michel deformity, common cavity, and cochlear aplasia. Incomplete partition-III has its unique superiorly displaced LS (100%). CH-IV also has its unique mild anterosuperior displacement. Ears with a superiorly displaced TS usually (93.1%) had aplastic or hypoplastic semicircular canals. The FR is likely to be narrow in CH and severe IEMs.

CONCLUSIONS

The FN route is affected in IEMs, which must be kept in mind when operating on ears with IEMs. Especially in CH cases, all segments of the FN can be abnormal.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:E696-E703, 2020.

Is CT necessary for imaging paediatric congenital sensorineural hearing loss?

Objectives: To determine if MRI alone is adequate for pre-operative assessment of paediatric congenital sensorineural hearing loss (SNHL). While aberrant intratemporal facial nerve anatomy is usually occult on MRI, we postulate that the majority of cases have no adverse bearing on surgical outcomes.Methods: MRI and CT of the temporal bones were analysed in 240 children who underwent both on the same day for SNHL. Only children under the age of 5 years with no reported clinical syndrome or dysmorphic external ear anatomy were included.Results and discussion: 169 patients satisfied the inclusion criteria. MRI detected 32/54 cases of cochleovestibular dysplasia, with the majority of the additional CT findings comprising subtle incomplete partition type 2 (IP2) anomalies. Of the 22 cases not evident on MRI, 13 patients also had large vestibular aqueduct syndromoe (LVAS), which would have prompted evaluation with CT due to the near universal co-existence of these entities. Only one patient exhibited aberrant intratemporal facial nerve anatomy that may have conferred surgical risk and was occult on MRI.Conclusion: In a defined paediatric SNHL cohort, the addition of routine temporal bone CT to MRI offers limited additional yield but confers a significant radiation burden on a young population.

Efficacy of a selective imaging paradigm prior to pediatric cochlear implantation

OBJECTIVES/HYPOTHESIS

There is no consensus on the necessary preoperative imaging in children being evaluated for cochlear implantation (CI). Dual-imaging protocols that implement both magnetic resonance imaging (MRI) and high resolution computed tomography (HRCT) create diagnostic redundancy in the face of potentially unnecessary radiation and anaesthetic exposure. The objectives of the current study were to examine the efficacy of an MRI-predominant with selective HRCT imaging protocol.

STUDY DESIGN

Retrospective review.

METHODS

The protocol was implemented over a 4-year period, during which HRCT was obtained in addition to MRI only if specific risk factors on clinical assessment were identified or if imaging findings in need of further evaluation were detected on initial MRI evaluation. Retrospective review of operative reports and prospective review of imaging were performed; anesthetic exposure and costing information were also obtained.

RESULTS

Of the 240 patients who underwent assessment, seven (2.9%) had combined HRCT and MRI performed concurrently based on initial clinical assessment, 15 (6.3%) underwent HRCT based on imaging anomalies found on MRI, and MRI alone was ordered for the remaining 218 (90.1%). All patients were implanted without complication. Overall, radiation exposure, general anesthesia (GA), and healthcare costs were reduced.

CONCLUSIONS

MRI alone can be used in the vast majority of cases for preoperative evaluation of pediatric CI candidates resulting in a significant reduction in healthcare costs, radiation, and GA exposure in children. The additional need for HRCT occurs in a small proportion and can be predicted up front on clinical assessment or on initial MRI.

LEVEL OF EVIDENCE

4 Laryngoscope, 129:2627-2633, 2019.

Telmesani Radiological Classification of the Location of the Vertical Segment of the Facial Nerve: Impact on Surgical Approach in Cochlear Implant Surgery

OBJECTIVE

This study was conducted to establish a radiological classification of the location of the vertical segment of the facial nerve (VSFN) and to see if this has implications on the surgical technique needed to access the round window niche (RWN) in cochlear implant (CI) surgery.

STUDY DESIGN

Observational case series study.

SETTING

Tertiary referral center.

PATIENTS

One hundred twenty seven patients underwent CI surgery, and high resolution computed tomography (HRCT) of 140 temporal bones was studied. The data that were collected consisted of the patient's age, sex, radiological inner ear malformations (IEM), and the surgical technique used to access the RWN.

MAIN OUTCOME MEASURES

The radiologic location of the VSFN in relation to the lateral semicircular canal in the coronal plane of HRCT and its implication on the surgical approach used to access the RWN in CI surgery.

RESULTS

A statistically significant association is present between the radiological location of the VSFN and the surgical approach used (p < 0.001).There was insignificant correlation between the locations of the VSFN and the patient's age, sex, and IEM as the p > 0.05.

CONCLUSIONS

On HRCT (0.6 mm) in the coronal plane, the position of the VSFN in relation to the lateral semicircular canal is correlated with the alternative approaches that must be taken during CI surgery.

Facial nerve anomalies in paediatric cochlear implant candidates: radiological evaluation

Background:

Pre-operative radiological identification of facial nerve anomalies can help prevent intra-operative facial nerve injury during cochlear implantation. This study aimed to evaluate the incidence and configuration of facial nerve anomalies and their concurrence with inner-ear anomalies in cochlear implant candidates.

Methods:

Inner-ear and concomitant facial nerve anomalies were evaluated by magnetic resonance imaging and temporal high-resolution computed tomography in 48 children with congenital sensorineural hearing loss who were cochlear implant candidates.

Results:

Inner-ear anomalies were present in 11 out of 48 patients (23 per cent) and concomitant facial nerve anomalies were present on 7 sides in 4 patients (7 per cent of the total). Facial nerve anomalies were accompanied by cochlear or vestibular malformation.

Conclusion:

Potential facial nerve abnormalities should always be considered in patients with inner-ear anomalies. Pre-operative facial nerve imaging can increase the surgeon's confidence to plan and perform cochlear implantation. Magnetic resonance imaging should be used to detect inner-ear anomalies; if these are identified, temporal high-resolution computed tomography should be used to evaluate the facial nerve.

Cochlear Implantation in Patients With CHARGE Syndrome

OBJECTIVE

To determine the optimal surgical approach for cochlear implantation (CI) preoperatively based on the spatial relation of a displaced facial nerve (FN) and middle ear structures and to analyze clinical outcomes of CHARGE syndrome.

METHODS

Facial nerve displacement and associated deviation of inner ear structures were analyzed in 13 patients (17 ears) with CHARGE syndrome who underwent CI. Surgical accessibility through the facial recess was assessed based on anatomical landmarks. Postoperative speech performance and associated clinical characteristics were analyzed.

RESULTS

The most consistently identified ear anomalies were semicircular canal aplasia (100%), ossicular anomaly (100%), and vestibular hypoplasia (88%). Facial nerve displacement was found in 77% of cases (anteroinferior: 47%, anterior: 24%, inferior: 6%). The width of available surgical space around facial recess was significantly greater in cases of facial recess approach (2.85 ± 0.9 mm) than those of alternative approach (0.12 ± 0.29 mm, P = .02). Postoperatively, 53% achieved better than category 4 on the categories of auditory perception (CAP) scale. The CAP category was significantly correlated with internal auditory canal diameter (P = .025) and did not differ according to the applied surgical approach.

CONCLUSION

Preoperative determination of surgical accessibility through facial recess would be useful for safe surgical approach, and successful hearing rehabilitation was achievable by applying appropriate surgical approaches.

The feasibility of endoscopic transcanal approach for insertion of various cochlear electrodes: a pilot study

To determine the feasibility of inserting various types of electrode arrays using an endoscopic transcanal approach into the cochlea via the round window membrane (RWM). All the procedures were performed by the first author and started with a cortical mastoidectomy. A six o'clock vertical incision was made in the meatal skin, and a posterior tympano-meatal flap was elevated transmeatally to expose the middle ear cavity using a rigid 0° endoscope (diameter 3 mm, length 14 cm). The chorda tympani nerve (CTN) and body of the incus were exposed. The RWM was incised, and the electrodes were passed through the tunnel from the mastoid to the epitympanum, medial to the CTN and lateral to the incus into the round window (RW) in seven procedures. In the other six cases, an open groove had been drilled, starting superiorly and laterally to the CTN and ending in the mastoid region. After electrodes insertion, the groove was filled with bone dust and covered with a large piece of fascia prior to repositioning of the tympano-meatal flap. Complete electrode insertion (7 Nucleus Contour Advance, 5 Concerto and 1 HiRes90K) via the RW was achieved in all 13 cases. Endoscopic CI was more feasible for insertion of concerto electrode followed by HiRes90K and Nucleus. An assistance of another surgeon was required for removal of stylet in the "off-the-stylet technique" utilized for implantation of nucleus electrode. Endoscopic transcanal implantation of different cochlear electrodes through the RW is feasible in both children and adults and can be used as first surgical option or as a complementary to the traditional posterior tympanotomy approach.

Surgery of the ear and the lateral skull base: pitfalls and complications

Surgery of the ear and the lateral skull base is a fascinating, yet challenging field in otorhinolaryngology. A thorough knowledge of the associated complications and pitfalls is indispensable for the surgeon, not only to provide the best possible care to his patients, but also to further improve his surgical skills. Following a summary about general aspects in pre-, intra-and postoperative care of patients with disorders of the ear/lateral skull base, this article covers the most common pitfalls and complications in stapes surgery, cochlear implantation and surgery of vestibular schwannomas and jugulotympanal paragangliomas. Based on these exemplary procedures, basic "dos and don'ts" of skull base surgery are explained, which the reader can easily transfer to other disorders. Special emphasis is laid on functional aspects, such as hearing, balance and facial nerve function. Furthermore, the topics of infection, bleeding, skull base defects, quality of life and indication for revision surgery are discussed. An open communication about complications and pitfalls in ear/lateral skull base surgery among surgeons is a prerequisite for the further advancement of this fascinating field in ENT surgery. This article is meant to be a contribution to this process.