Facial nerve anomalies in association with congenital hearing loss

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.

Isolated Congenital Middle Ear Malformations: Comparison of Preoperative High-Resolution CT and Surgical Findings

Objectives:

To compare preoperative temporal bone high-resolution computed tomography (HRCT) readings to intraoperative findings during exploratory tympanotomy for suspected cases of isolated congenital middle ear malformations (CMEMs) and summarize the malformations that can and cannot be diagnosed with HRCT.

Methods:

A retrospective study was conducted. All cases were confirmed as isolated CMEMs during surgery. Detailed clinical records were reviewed, with a focus on imaging and surgical findings.

Results:

One hundred and thirty-two patients and 145 ears were reviewed. Ninety cases (62.1%) could be identified as isolated CMEMs and at least one as middle ear anomaly using preoperative HRCT. Fifty-five cases (37.9%) were reported to be completely normal and the patients underwent exploratory tympanotomy to determine the final diagnosis. Stapes fixation, either alone or associated with other ossicular chain anomalies, contributed to 53.1% of the cases. Most cases of aplasia or dysplasia of the ossicular chain, for example, aplasia/dysplasia of the long process of the incus, aplasia of the stapes’ superstructure, and atresia of the oval window were easily identified in preoperative HRCT. However, fixation of the ossicular chain can be elusive in HRCT, and exploratory tympanotomy is needed for a definitive diagnosis.

Conclusions:

HRCT provides helpful preoperative clinical information in CMEM and may obviate the need for middle ear exploration in some cases. The negative findings (anomalies that are difficult to identify through preoperative HRCT) and the positive findings (anomalies that are relatively easy to identify through preoperative HRCT) were summarized.

Morphometric properties of the facial canal in children: A retrospective computed tomography study

PURPOSE

The main objective of the study was to examine the morphometric development of the facial canal in temporal bones aged from one to 18 years for pediatric otosurgeons and neurosurgeons.

METHODS

The study was performed on 41 patients including cochlear implantation cases (20 females and 21 males) with a mean age of 6.44 ± 5.79 years. All the measurements belonging to the facial canal including the length, width and angles of its segments were performed using the data of computed tomography assessment.

RESULTS

The numerical data of the facial canal segments were not different in terms of sexes or sides, statistically (p > 0.05). The width of the labyrinthine segment (p = 0.145), the length of the tympanic segment (p = 0.555), the first (p = 0.067) and second (p = 0.060) genu angles seemed to reach adult size at two years of age. In addition, the length of the labyrinthine segment (p = 0.064) and the width of the mastoid segment (p = 0.264) seemed to attain adult size at four years, while the width of the meatal foramen (p = 0.264) seemed to arrive adult size at seven years. However, the length of the mastoid segment and the width of the tympanic segment were developing independently of increasing age between 1 and 18 years.

CONCLUSION

Our data suggested that, contrary to the general acceptance in the literature, the dimension of the facial canal segments show remarkable changes during the transition from intrauterine life to adult life. The regression equations representing the facial canal growth dynamic in children may be useful for otosurgeons to estimate the size of its segments and to prevent iatrogenic injury during early childhood surgeries such as cochlear implantation.

Morphometric properties of the facial nerve in fetal temporal bones

OBJECTIVES

The main aim of the study was to examine the development and course of the facial nerve within fetal temporal bones from an anatomical and neuro-otological perspective.

METHODS

The study was conducted on 32 temporal bones from obtained fetuses (7 females, 9 male), on a mean gestational age of 26.75 ± 4.36 (range, 20-34) weeks from the collection of the Anatomy Department of Medicine Faculty. All the measurements were collected with a digital image analysis software.

RESULTS

Neither male/female nor right/left significant differences were observed in relation with the algebraic data of the segment lengths and angles of the facial nerve (p > 0.05). Linear functions for meatal, labyrinthine, tympanic, and mastoid segment lengths of the facial nerve were calculated as: y = -1.206 + 0.200 × Age (weeks), y = -1.868 + 0.153 × Age (weeks), y = -2.327 + 0.325 × Age (weeks), and y = -1.507 + 0.246 × Age (weeks), respectively. In addition, linear functions for first and second genu angles were calculated as: y = 105.475-0.117 × Age (weeks) and y = 140.446-0.042 × Age (weeks), respectively.

CONCLUSION

The regression equations and the scatter plot with increment curve, representing the growth dynamics of the facial nerve can be used for estimating its lengths and for understanding its development. The data suggest that there is a dramatic change transition from fetal life to the gathered data of adulthood in the length of meatal and mastoid segments as well as in the second genu angle; in addition, there is a partial change in the length of labyrinthine and tympanic segments as well as in the first genu angle.

Reporting and Description for Congenital Middle Ear Malformations to Facilitate Surgical Management

Introduction:

The aim of this work was to report and describe the different types of congenital middle ear malformations in order to guide surgical treatment approaches and improve outcomes for affected patients.

Methods:

The authors reviewed patients with congenital middle ear malformations who received surgical treatment between September 2010 and March 2017. Patient characteristics, middle ear deformities, and surgical procedures were documented.

Results:

In this retrospective study, 35 patients were reviewed. A description of middle ear malformation was proposed that considers ear embryogenesis and focuses on stapes deformity, with the main purpose of facilitating surgical approach selection to reconstruct the ossicular chain. Patients were classified into 3 categories: type I (19 cases), mobile stapes footplate, which included type Ia with normal stapes suprastructure and type Ib with abnormal stapes suprastructure; type II (4 cases), fixed stapes footplate, which included type IIa with normal ossicular chain and type IIb with abnormal ossicular chain; and type III (12 cases), oval window bony atresia or aplasia, with or without round window atresia. Types II and III could have concomitant aberrant facial nerve. Different surgical approaches are described.

Conclusions:

The authors describe the different types of congenital middle ear malformations. This category description considers ear embryogenesis and is focused on stapes deformity. It may provide better understanding of disease development and guide modern hearing reconstructive 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.

Imaging spectrum of facial nerve lesions

The facial nerve is affected by a wide variety of pathologies, including congenital, traumatic, inflammatory, and neoplastic conditions. Imaging plays a vital role in the diagnosis of these pathologies. The facial nerve has a complex anatomy and course. A strong grasp of normal facial nerve anatomy is essential for the radiologist to maintain a high level of diagnostic sensitivity. This article details the normal imaging anatomy of the facial nerve and the imaging features of common facial nerve pathologies.

Stapes fixation accompanied with abnormal facial nerve pathway

The patient was a 52-year-old woman. She had been aware of her bilateral hearing loss since she was 20 years old. The hearing in her left ear started to deteriorate at the age of 49. Pure-tone audiometry showed a bilateral mixed hearing loss. The hearing levels for the right ear and the left ear were 52 dB and 68 dB, respectively. There were no remarkable findings in a computed tomography (CT) scan of the temporal bone. We suspected that she had otosclerosis, and an operation was performed on her left ear. When the incudostapedial joint (I-S joint) was exposed to investigate the movement of the stapes, a soft white band that ran under the superstructure of the stapes was noted. By using a nerve monitoring system, we confirmed that the white band was the bare facial nerve. The ossicular chain was normal, except for a malformed stape due to the facial nerve, and the footplate of the stapes was fixed. Therefore, she was diagnosed as having otosclerosis with an abnormal facial nerve pathway. The malformed superstructure of the stapes was removed carefully. When the ectopic facial nerve was shifted to anteroinferior side, the oval window could be seen. Stapedotomy using a Teflon piston prosthesis was performed with no complications.

Congenital unilateral facial nerve palsy as an unusual presentation of BOR syndrome

Congenital facial nerve palsy (CFNP) is a rare condition that can be generally categorized as developmental or traumatic. Though trauma during birth is the most common cause, sometimes CFNP is observed in association with genetic syndromes and congenital hearing loss and structural anomalies of the middle and inner ear. CFNP is infrequently reported in association with branchio-oto-renal (BOR) syndrome. We present a case of a 4-day-old infant girl with a familial history of renal disease, who was hospitalized because of congenital unilateral facial palsy, which subsequently appeared to be a part of BOR syndrome and led to the diagnosis of congenital bilateral renal hypoplasia, renal failure, and secondary arterial hypertension. This case proves that sometimes rare manifestations of BOR syndrome may be one of the first signs of an underlying syndrome. Issues regarding patterns of BOR syndrome inheritability and expressivity that we encountered are also discussed. Patients with a familial history of BOR syndrome should be carefully inspected after birth, especially in suspected cases such as newborns with preauricular pits and/or facial nerve palsy.

Labyrinthotomy or vestibulotomy in anatomic and congenital variations of the oval window and facial nerve

OBJECTIVE

To present the results of our experience with labyrinthotomy or vestibulotomy in cases where the oval window is blocked by the facial nerve and in the presence of bilateral congenital agenesis of the oval window, respectively.

STUDY DESIGN

Retrospective analysis of the records of the patients operated in two different centers.

METHODS

Between 2007 and 2012, 5 ears of 4 patients who were operated on in two different clinics with a presumptive diagnosis of otosclerosis were included in the study. There were 3 female patients and 1 male. The ages ranged from 10 to 26 (mean 19 years). All patients had unilateral conductive hearing loss except 1 (10-year-old girl or patient 1). Pure tone averages were calculated at the frequencies 0.5, 1, 2 and 4 kHz both pre- and postoperatively according to the Committee on Hearing and Equilibrium 1995 Guidelines for the Evaluation of Results of Treatment of Conductive Hearing Loss. All patients underwent a middle ear exploration and postoperatively the initial audiological examination was performed after 6 months.

RESULTS

Retrospective analysis revealed that vestibulotomy or labyrinthotomy was performed in 5 ears of 4 patients. Postoperative dizziness was encountered in 2 patients who had vestibulotomy due to oval window agenesis, which ceased spontaneously at 1 month postoperatively. The perioperative period was otherwise uneventful. None of the patients had sensorineural hearing loss or deterioration of hearing. There was a significant improvement in hearing after the operation. A 28-dB improvement in the mean air conduction pure tone thresholds was achieved.

CONCLUSION

Vestibulotomy and labyrinthotomy are safe and effective procedures in terms of hearing restoration, which can be applied in cases of congenital agenesis of the oval window or obstruction of the oval window by the facial nerve.

Congenital bilateral facial nerve hypoplasia with sensorineural hearing loss: a case report

A 3-year-old child presented with congenital bilateral facial nerve palsy with bilateral profound sensorineural hearing loss. High Resolution Computed Tomogram (HRCT) of the temporal bones found bilateral atresia of cochlear nerve canals, incomplete partition of the cochleae and narrow facial nerve canals. Magnetic resonance imaging (MRI) revealed bilateral hypoplasia of facial nerves and aplasia of both vestibulocochlear nerves. There have been no other reported cases with this presentation. The possible aetiology and treatment options for the patient are discussed. We highlighted the review of aplasia/hypoplasia of the facial nerve and hypoplasia of cochlear nerve canal.

Congenital incudostapedial anomalies in adult stapes surgery: a case-series review

OBJECTIVES

The management of developmental anomalies of the ossicular chain and otic capsule in stapes surgery tests the otologist's diagnostic skills and flexibility in technique and prosthesis choice. We review our experience in managing various incudostapedial developmental anomalies discovered during middle ear exploration for suspected otosclerosis in adult patients.

DESIGN

A retrospective case-series review was used.

SETTING

The study was set at a military tertiary referral center.

PATIENTS AND OTHER PARTICIPANTS

A review of 185 stapes procedures yielded 8 cases of identified congenital anomalies of the stapes or incudostapedial complex including congenital absence of the oval window with malformed incus and stapes, columellar-type stapes with promontory fixation, stapes superstructure fixation to the fallopian canal, and malformed incus with stapes superstructure fixation to the promontory.

INTERVENTIONS

The developmental anatomy and surgical technique in each case were reviewed. The surgical technique used in each case varied depending on the specific ossicular abnormality found and whether both the stapes and incus were affected.

MAIN OUTCOME MEASURES

Comparison of preoperative and postoperative audiometric testing results was performed.

RESULTS

All 8 ears (7 patients) that underwent a stapes procedure for either an isolated congenital stapes anomaly or a combined incudostapedial anomaly had a favorable hearing outcome, with 7 ears improving to within 10-dB and 1 ear to within 13-dB air-bone gap on postoperative audiometry.

CONCLUSIONS

Despite unanticipated findings of congenital anomalies of the stapes and incus during middle ear exploration for conductive hearing loss, a flexible management approach can lead to successful hearing outcomes.

Genetic syndromes involving hearing

OBJECTIVE

The fundamental processes involved in the mechanism of hearing seem to be controlled by hundreds of genes and hereditary hearing impairment may be caused by a large variety of genetic mutations in different genes. Approximately 150 loci for monogenic syndromic and non-syndromic hearing impairment (HI) disorders have been mapped to the human genome. The identification of these genes and functional analysis of the proteins they encode, are paving the way towards a better understanding of the physiology and pathophysiology of the auditory system. To date, approximately 50 causative genes have been identified.

METHODS

The clinical and neuroradioldical findings of syndromal hearing impairment are analysed.

RESULTS

This paper presents an updated report on genetic syndromes in which a hearing impairment is involved, with a particular attention to the ones associated with external ear and craniofacial malformations.

CONCLUSIONS

Concepts in human genetics are rapidly evolving together with technologies. The concept itself of gene is changing. A genetic diagnosis of syndromal hearing impairment has many practical consequences: it can implies specific prognosis, specific management, specific recurrence risk in relatives and, if the diagnosis is confirmed at the molecular level, possibility of a specific early prenatal diagnosis for severe syndromes. It is important to highlight the necessity that the pediatric otolaryngologist must have a close collaboration with a clinical geneticist and a neuroradiologist.

Another cause for conductive hearing loss with present acoustic reflexes

There are numerous potential causes of conductive hearing loss (HL). It is important to obtain a thorough history and perform a complete examination, including audiometric testing and radiographic evaluation when necessary. In this report, we present a patient with an intact tympanic membrane, no history of ear disease or trauma who as an adult developed progressive, conductive HL because of an anomalous course of a dehiscent facial nerve. In the patient with a conductive HL and at least partially intact reflexes, superior semicircular canal dehiscence, fracture of the stapes superstructure proximal to the tendon, other third window phenomena, and now dehiscence of the facial nerve resulting in decreased mobility of the ossicular chain must be considered.