Oval window atresia: a novel surgical approach and pathognomonic radiological finding

Audiologic Outcomes After Vestibulotomy in Patients With Congenital Absence of the Oval Window

OBJECTIVE

To examine the clinical features and surgical outcomes in patients with congenital absence of the oval window (CAOW), and to investigate the potential factors that affect audiologic results.

STUDY DESIGN

A retrospective chart review.

SETTING

A tertiary academic center.

PATIENTS AND INTERVENTION

A total of 17 ears among 16 patients were confirmed to have CAOW. Among them, 13 ears underwent vestibulotomy for hearing reconstruction. Clinical parameters associated with the hearing outcomes were analyzed.

MAIN OUTCOME MEASURES

A mean air-bone gap (ABG) after 6-month and long-term follow-up was compared with preoperative measurements.

RESULTS

Intraoperative findings showed that anomalies of the malleus or incus were observed in 11 ears (64.7%), stapes anomalies were present in all ears (100%), and facial nerve anomalies were present in 10 ears (58.8%). Because of unfavorable facial nerve anomalies, hearing reconstruction was aborted in four cases (23.5%). In the hearing reconstruction group, the mean ABG at 6 months postoperation was significantly reduced after compared with the preoperative value (44.0 ± 8.4 dB versus 58.8 ± 9.1 dB, p = 0.006). After dividing ears into a success subgroup (ABG ≤ 30 dB, seven ears) and non-success subgroup (ABG > 30 dB, six ears), the use of a drill during vestibulotomy was significantly related to a poor hearing outcome (100% versus 16.7%, p = 0.015). The long-term follow-up result (mean, 60 mo) revealed no deterioration compared with the 6-month postoperative result. Five ears (29.4%) underwent revision surgery, and three of them showed ABG improvements. No serious complications were reported.

CONCLUSION

Vestibulotomy is an effective and safe option for hearing restoration in patients with CAOW, particularly when the use of a drill is not required. The long-term audiologic outcome is also reliable.

The Facial Nerve: Anatomy and Pathology

The facial nerve is the seventh cranial nerve and consists of motor, parasympathetic and sensory branches, which arise from the brainstem through 3 different nuclei (1). After leaving the brainstem, the facial nerve divides into 5 intracranial segments (cisternal, canalicular, labyrinthine, tympanic, and mastoid) and continues as the intraparotid extracranial segment (2). A wide variety of pathologies, including congenital abnormalities, traumatic disorders, infectious and inflammatory disease, and neoplastic conditions, can affect the facial nerve along its pathway and lead to ​​weakness or paralysis of the facial musculature (1,2). The knowledge of its complex anatomical pathway is essential to clinical and imaging evaluation to establish if the cause of the facial dysfunction is a central nervous system process or a peripheral disease. Both computed tomography (CT) and magnetic resonance imaging (MRI) are the modalities of choice for facial nerve assessment, each of them providing complementary information in this evaluation (1).

Bone-conduction hearing aid is effective in congenital oval window atresia

BACKGROUND

Implantable bone-conduction hearing aids (BCHA) are effective in patients with congenital ear malformations.However, there is no large sample study to verify the efficacy of Bonebridge in patients with congenital oval window atresia.

OBJECTIVES

To investigate efficiency of implantable bone-conduction hearing aids in Mandarin-speaking patients with congenital oval window atresia.

MATERIAL AND METHODS

We retrospectively analyzed 15 patients, who were confirmed with either unilateral or bilateral congenital oval window atresia by temporal bone CT. All patients were implanted with a bone-conduction hearing device between July 2016 and July 2019 at Beijing Tongren Hospital, Capital Medical University. Pure tone audiometry (PTA), air-bone gap (ABG), speech discrimination scores (SDSs), and hearing thresholds were performed.

RESULTS

Postoperative complications including facial paralysis were particularly rare. Unaided mean sound field threshold was 62.2 ± 10.5 dBHL and that with implantable bone-conduction hearing aids was 39.1 ± 13.2 dBHL (p < 0.01). The mean speech discrimination scores improved greatly (p < 0.01), specifically with regard to sentence and disyllabic words.

CONCLUSIONS

Patients with congenital oval window atresia often show moderate to severe conductive hearing loss. Implantable bone-conduction hearing aids are considerably safe and stable for hearing rehabilitation. It is a novel treatment modality for Mandarin-speaking patients with congenital oval window atresia.

[Hearing rehabilitation with the Vibrant Soundbridge in patients with congenital middle ear malformation]

BACKGROUND

Congenital aural atresia, which is usually unilateral, causes hearing loss and aesthetic impairment. Besides tympanoplasty with/without canalplasty and bone conduction devices, active middle ear implants are also available for functional rehabilitation.

OBJECTIVE

This article aims to present a contemporary review on the treatment possibilities for middle ear malformations, with a focus on audiological rehabilitation with the Vibrant Soundbridge.

MATERIALS AND METHODS

A selective literature search for treatment possibilities was performed in PubMed up to October 2020, and personal clinical experiences are reported.

RESULTS

The Vibrant Soundbridge, which is approved for children ≥ 5 years, is suitable for treatment of middle ear malformations with a Jahrsdoerfer score ≥ 5. Although implantation of a Vibrant Soundbridge is surgically more demanding than implantation of a bone conduction device, the method is safe, delivers good auditory results (superior to bone conduction devices in terms of speech understanding and spatial hearing), does not involve intensive postsurgical care, and rarely requires revision surgery. The Vibrant Soundbridge can be coupled to (remnants of) the ossicular chain or the round window.

CONCLUSION

The Vibrant Soundbridge is an appropriate treatment method in patients with middle ear malformations who have suitable anatomical preconditions.

Anatomic features of the fetal round and oval windows, and their relations with the tympanic nerve

OBJECTIVE

The study aimed to examine morphometric properties of the round window (RW) and oval window (OW) and to show their relation with the tympanic nerve (the Jacobson's nerve, JN) in human fetuses from the otologic surgeon's perspective.

METHODS

Thirty temporal bones of 15 fetal cadavers (8 males, 7 females) aged with 24.40 ± 3.71 weeks were included in the study. The height, width and surface area of the RW and OW and also distance from the JN to the OW and RW were measured.

RESULTS

The height, width and surface area of the RW in this work were measured as 1.48 ± 0.25 mm, 1.57 ± 0.37 mm, and 2.05 ± 0.69 mm², respectively. The RW was detected as round-shaped (8 cases, 26.7%), oval-shaped (15 cases, 50%), and dome-shaped (7 cases, 23.3%). The height, width and surface area of the OW were measured as 1.42 ± 0.26 mm, 2.90 ± 0.44 mm, and 3.63 ± 0.74 mm², respectively. The OW was observed as oval-shaped (15 cases, 50%), kidney-shaped (10 cases, 33.3%), D-shaped (4 cases, 13.3%), and trapezoid-shaped (1 case, 3.3%). The JN was found 1.21 ± 0.60 and 1.18 ± 0.54 mm away from the RW and OW, respectively.

CONCLUSION

This study containing morphological data about the shapes, diameters and area of the RW and OW may be useful to predict surgical difficulty, and to select implants of suitable size preoperatively for the windows. Knowing the relationship between the JN and the windows can be helpful to avoid iatrogenic injuries of the nerve.

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.

Comparison of various bone cement ossiculoplasty techniques and functional results

OBJECTIVE

In this study, functional results of different bone cement ossiculoplasty techniques are compared.

METHODS

Retrospective case review at a tertiary referral center. Patients who underwent middle ear surgery and bone cement ossiculoplasty between 2006-2012 were included. A total of 52 patients, including 30 patients with 'Incus to stapes' (Group 1) and 13 patients with 'malleus to stapes' (Group 2), five patients with 'incudoplasty + stapedotomy' (Group 3), and four patients with 'malleus to incus' (Group 4) ossiculoplasty were enrolled in the study. Pre-operative and post-operative audiological findings of each group were evaluated.

RESULTS

The mean hearing gain (the difference between pre-operative and post-operative air bone gap (ABG)) was 13 dB for Group 1, 30 dB for Group 2, 24 dB for Group 3, and 9 dB for Group 4. The pre-operative air pure tone averages (PTA) of groups 1, 2, and 3 improved significantly in the post-operative period (p < 0.05). Closure of post-operative ABG of patients to less than 20 dB and 10 dB were as follows: ∼70% and 43% in group 1; 86% and 76% in group 2; 100% and 60% in group 3; and 75% and 50% in group 4, respectively.

CONCLUSIONS

The results showed that glass ionomer cement is a simple and effective method for reconstruction of ossicular discontinuity in various ossicular chain pathologies and can be an alternative to conventional rebridging techniques such as sculpted incus interposition or partial ossicular replacement prosthesis (PORP).