Congenital ossicular chain malformations with mobile stapes in children: Results in 17 cases

Endoscopic Surgery for a Case of Congenital Cholesteatoma with Ossicular Chain Anomaly

The simultaneous occurrence of congenital ossicular anomalies and congenital cholesteatoma (CC) is exceedingly rare. This report describes the case of an 11-year-old boy who presented with conductive hearing loss, characterized by an average air conduction threshold of 50 dB in the left ear, without any prior otologic history. Preoperative assessments suggested the presence of CC, with suspicion of ossicular chain malformation. The patient underwent ear endoscopic surgery, during which the lesion was excised, and the ossicular chain was reconstructed using a titanium ossicular prosthesis. Postoperative follow-up indicated successful healing, with a significant improvement in hearing, as demonstrated by a reduction in the air conduction threshold to 15 and a hearing gain of 35 dB.

Implantable hearing devices in clinical practice. Systematic review and consensus statements

Objective

Implantable hearing devices represent a modern and innovative solution for hearing restoration. Over the years, these high-tech devices have increasingly evolved but their use in clinical practice is not universally agreed in the scientific literature. Congresses, meetings, conferences, and consensus statements to achieve international agreement have been made. This work follows this line and aims to answer unsolved questions regarding examinations, selection criteria and surgery for implantable hearing devices.

Materials and methods

A Consensus Working Group was established by the Italian Society of Otorhinolaryngology. A method group performed a systematic review for each single question to identify the current best evidence on the topic and to guide a multidisciplinary panel in developing the statements.

Results

Twenty-nine consensus statements were approved by the Italian Society of Otorhinolaryngology. These were associated with 4 key area subtopics regarding pre-operative tests, otological, audiological and surgical indications.

Conclusions

This consensus can be considered a further step forward to establish realistic guidelines on the debated topic of implantable hearing devices.

Surgical outcome in class 4 congenital anomalies of the ossicular chain: a systematic review of the literature

OBJECTIVE

To review hearing and surgical outcomes after reconstructive middle ear surgery in class 4 congenital middle ear anomalies (CMEA), e.g., patients with oval- or round window atresia of dysplasia.

DATA SOURCES

Pubmed/Medline, Embase and Cochrane library.

REVIEW METHODS

Articles containing data on hearing outcomes and complications after reconstructive ear surgery in class 4 anomalies were analyzed and critically appraised. The following data were included and reviewed: patient demographics, audiometric testing, surgical techniques, complications, revision surgeries and their outcomes. Risk of bias was determined, and GRADE certainty of evidence was assessed. Primary outcomes were postoperative air conduction thresholds (AC), change in AC, and success rates (closure of the ABG to within 20 dB), the occurrence of complications (most importantly sensorineural hearing loss) and the long-term stability of hearing results (> 6-month follow-up) and occurrence of recurrence of preoperative hearing loss.

RESULTS

Success rates varied from 12.5 to 75% at long-term follow-up with larger cohorts reporting success rates around 50%, mean postoperative gain in AC varied from 4.7 to 30 dB and - 8.6 to 23.6 dB at, respectively, short- and long-term follow-up. No postoperative change in hearing occurred in 0-33.3% of ears, and recurrence of hearing loss occurred in 0-66.7% of ears. SNHL occurred in a total of seven ears across all studies of which three experienced complete hearing loss.

CONCLUSION

Reconstructive surgery can be an effective treatment option which should be considered in patients with very favorable baseline parameters, while also considering the substantial risk of recurrence of hearing loss, the possibility of unchanged hearing despite surgery and the rare occurrence of SNHL.

LEVEL OF EVIDENCE

2c.

Combined analysis of finite element model and audiometry provides insights into the pathogenesis of conductive hearing loss

The middle ear transmits sound to the inner ear via vibrations in the eardrum and ossicles, and damage to the middle ear results in conductive hearing loss. Although conductive hearing loss can be corrected by surgery, the currently available clinical investigations cannot always diagnose the ossicular chain pathology underlying the conductive hearing loss, and even intraoperative findings can be equivocal. Acoustic analysis using finite element models (FEMs) can simulate the sound pressure change at an arbitrary site for each frequency. FEMs are used in acoustic engineering to simulate the frequency-dependent sound pressure distribution at discrete cells in a simulated model and analyze the effects of specific parameters on the audiogram. However, few reports have compared the numerical results obtained using FEMs with data from clinical cases. We used FEMs to simulate audiograms of the air-bone gap (ABG) for various ossicular chain defects and compared these with preoperative audiograms obtained from 44 patients with a normal tympanic membrane who had otosclerosis, middle ear malformations or traumatic ossicular disruption. The simulated audiograms for otosclerosis and attic fixation of the malleus-incus complex both exhibited an up-slope but could be distinguished from each other based on the ABG at 1000 Hz. The simulated audiogram for incudostapedial joint discontinuity exhibited a peak at around 750 Hz and a down-slope above 1000 Hz. In general, the simulated audiograms for otosclerosis, attic fixation and incudostapedial joint discontinuity were consistent with those obtained from clinical cases. Additional simulations indicated that changes in ossicular mass had relatively small effects on ABG. Furthermore, analyses of combination pathologies suggested that the effects of one defect on ABG were added to those of the other defect. These FEM-based findings provide insights into the pathogenesis of conductive hearing loss due to otosclerosis, middle ear malformations and traumatic injury.

Audiological characteristics and effect of endoscopic surgery for simple congenital malformation of ossicular chain

OBJECTIVE

To analyze the audiological characteristics and surgical results in patients undergoing surgery for simple congenital ossicular chain malformation, and the effect of endoscopic surgery.

METHODS

A retrospective review was performed on 86 patients who underwent surgery for the congenital malformation of the ossicular chain. Clinical characteristics and audiometric data were analyzed. Fifty-eight patients had detailed postoperative data, and the preoperative and postoperative audiometric results were compared. The subjects were further divided into endoscopic and microscopic groups, and their surgical effects were examined.

RESULTS

The preoperative audiometry results in the low-frequency group were worse than those in the high-frequency group (P < 0.05). A postoperative air-bone gap closure to 20 dB or less was achieved in 73.33% of the 60 ears of patients postoperatively. The postoperative air conduction and air-bone gap were significantly better than the preoperative ones (P < 0.05), and the improvement effect was the best in class III patients (P < 0.05). Postoperative hearing had no significant differences between the endoscopic and microscopic groups. However, endoscopic surgery also was more advantageous in terms of operating time (P < 0.05).

CONCLUSIONS

Preoperative pure tone audiometric results showed moderate or moderate-severe hearing loss, especially in the low-frequency area. The reconstruction of the auditory ossicle chain can achieve satisfactory results, especially in class III patients. Endoscopic and microscopic surgery in the treatment of simple congenital ossicular chain malformations can effectively improve postoperative hearing.

Morphometric study of the human malleus during prenatal development

OBJECTIVES

Establish normal reference values for the human malleus during the second and third trimesters of pregnancy, and describe its growth dynamics and ossification process.

METHODS

Thirty spontaneously aborted human fetuses, 12-36 weeks of age, were examined. Temporal bones were obtained en bloc and processed using the skeletal clearing and staining technique. Each malleus was obtained by microdissection. Measurements of anatomical points of the malleus were performed. Ossification was recorded. Statistics were applied.

RESULTS

Sixty mallei were obtained. At the end of development, the following measurements were obtained in millimeters: head length, 2.87 (2.30-3.44); neck length, 1.15 (0.92-1.38); manubrium length, 4.45 (3.75-5.16); total length, 8.51 (8.02-8.99); neck width, 1.33 (0.70-1.97); manubrium width, 0.84 (0.82-0.86); and Meckel cartilage width, 0.43 (0.06-0.95). The angle of the longitudinal axis of the malleus was 160° (156-164°). The ossification process of the malleus followed a stereotyped pattern that began at week 16, at the level of the neck, with a single center that expanded to the head and then to the manubrium. Toward the end of development, only the umbo remained cartilaginous. There were no sex-based differences in human malleus size during prenatal development. From the beginning of the second trimester of pregnancy, the longitudinal axis of the malleus acquires dimensions comparable to adults.

CONCLUSION

The study of the malleus development provides clues that would explain some anomalies in its development, and can influence decision-making during the placement and design of prostheses in the malleus.

Effect of ossicular chain deformity on reverse stimulation considering the overflow characteristics of third windows

Stimulating the round window membrane via an active actuator of the middle ear implant, named the reverse stimulation, has become an option to help patients with ossicular chain deformity (OCD) to restore hearing. However, there is still no concise description of how OCD affects reverse stimulation considering the overflow characteristics of third windows. In the present study, an impedance model considering the vestibular and cochlear aqueducts was used to investigate the dynamic response of the cochlea to reverse stimulation under OCD. First, a finite-element (FE) model of the middle ear and the ear canal was used to estimate the changes in reverse middle-ear impedance caused by ossicular chain fixation and ossicular chain interruption. Then, the impedance model was used to predict the reverse transfer function, which characterizes the effect of OCD on the dynamic response of the cochlea. The results show that ossicular chain fixation reduces the reverse stimulation's performance. Moreover, the existence of the third windows complicates the effect of ossicular chain fixation on the reverse stimulation and boosts obviously the reverse stimulation's performance at low frequencies. In contrast, regardless of the existence of third windows, ossicular chain interruption enhances the effect of reverse stimulation.

Congenital Anomalies of the Ossicular Chain: Surgical and Audiological Outcomes

Objectives:

In this study, we aim to analyze audiometric outcomes of middle ear surgery in patients with congenital middle ear anomalies.

Methods:

In this single center retrospective cohort study, audiological outcomes were extracted from patient files. Patients with a congenital middle ear anomaly treated surgically in a tertiary referral center between June 2015 and December 2020 were included. Pre- and postoperative short- and long-term audiometric data (at ≥3 and ≥10 months respectively) were compared to analyze hearing outcomes.

Results:

Eighteen ears (15 patients) were treated surgically with an exploratory tympanotomy. At short term follow up statistically significant improvements in air conduction thresholds and air-bone gaps were found. Hearing improved in 94.4% (17/18) of operated ears. Successful outcome, defined as an air-bone gap closure to within 20 dB after surgery, was reached in 44.4% (8/18). Serviceable hearing (air conduction ≤30 dB) was reached in 55.6% (10/18). Negative outcome (any significant deterioration in hearing) occurred in 1 patient: in this ear otitis media occurred during the postoperative course. At long term follow up, available for 50% of the cohort, hearing remained stable in 5 ears, improved in 1 ear and deteriorated in 3, all of which underwent revision surgery. Sensorineural hearing loss due to surgery, or other complications, were not encountered.

Conclusion:

middle ear surgery was found to be an effective treatment option to improve hearing in this cohort of patients with congenital middle ear anomalies. Surgical goals of obtained gain in air conduction thresholds and serviceable hearing levels were met by most patients without the occurrence of any iatrogenic sensorineural hearing loss.

Multicenter Study of Congenital Middle Ear Anomalies. Report on 246 Ears

OBJECTIVES/HYPOTHESIS

Congenital middle ear anomalies represent a relatively rare condition. This study aimed to describe the characteristics and the surgical outcomes for patients with middle ear anomalies.

METHODS

A multicenter study was conducted of consecutive patients with congenital middle ear anomalies who underwent primary surgical treatment between January 2008 and December 2017. Demographics, surgical procedures, and audiometric data were registered into the institutional database. Hearing changes and postoperative air-bone gap (ABG) were evaluated 1 year after surgery.

RESULTS

A total of 246 patients (246 ears) (median age: 14 years, range: 4-75 years old) were included in this study. Anomalies were subdivided using the Teunissen and Cremers classification: 53 ears (22%) were categorized as class I, comprising only stapes ankylosis; 35 ears (14%) as class II, having ossicular chain anomalies with stapes ankylosis; 139 ears (57%) as class III, having ossicular chain anomalies with a mobile stapes-footplate; and 19 ears (8%) as class IV, with aplasia of the oval window. Evaluation of hearing outcomes for 198 ears with more than 1 year of follow-up revealed that good postoperative ABG (≤20 dB) was achieved in 82% of class I, 68% of class II, 74% of class III, and 23% of class IV anomalies. The postoperative ABG in class IV was significantly worse than in class I (P < .001) or class III (P < .01).

CONCLUSIONS

This study demonstrated that class III anomalies comprised the majority of middle ear anomalies and surgical outcomes for class IV anomalies are unfavorable.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E2323-E2328, 2021.

Uncovering the secreted signals and transcription factors regulating the development of mammalian middle ear ossicles

The mammalian middle ear comprises a chain of ossicles, the malleus, incus, and stapes that act as an impedance matching device during the transmission of sound from the tympanic membrane to the inner ear. These ossicles are derived from cranial neural crest cells that undergo endochondral ossification and subsequently differentiate into their final functional forms. Defects that occur during middle ear development can result in conductive hearing loss. In this review, we summarize studies describing the crucial roles played by signaling molecules such as sonic hedgehog, bone morphogenetic proteins, fibroblast growth factors, notch ligands, and chemokines during the differentiation of neural crest into the middle ear ossicles. In addition to these cell-extrinsic signals, we also discuss studies on the function of transcription factor genes such as Foxi3, Tbx1, Bapx1, Pou3f4, and Gsc in regulating the development and morphology of the middle ear ossicles.

Case Report: Challenging Otologic Surgery in Patients With 22q11.2 Deletion Syndrome

Patients with 22q11.2 deletion syndrome frequently have conductive hearing loss and/or chronic otitis media. Otologic surgery is often opted for. We present two patients undergoing otologic surgery. This case report outlines the typical otologic surgical challenges in patients with 22q11.2 deletion syndrome. Case one is a 52 year old male patient with chronic otitis media who underwent a mastoidectomy. The pre-operative CT scan showed a fused lateral semicircular canal and vestibule. Peroperatively, the lateral semicircular canal could not be used as a landmark to identify the facial nerve. Case two is a 10 year old female patient with conductive hearing loss. A middle ear inspection was performed where a bony epitympanic fixation of the malleus was encountered. In addition, the manubrium of the malleus was atrophic and also fixated. The bony fixation was removed, as was the manubrium of the malleus. Otologists should be aware of these typical anatomical variations in patients with 22q11.2 deletion syndrome. We recommend to use CT scanning of the middle and inner ear when preparing for otologic surgery in 22q11.2 deletion syndrome.

Endoscopic Ossiculoplasty for the Management of Isolated Congenital Ossicular Chain Malformation: Surgical Results in 16 Ears

OBJECTIVE

The aim of this study is to describe the clinical characteristics and intraoperative findings and further evaluate the efficacy of endoscopic ossiculoplasty for the management of isolated congenital ossicular chain malformation.

METHODS

A retrospective study was performed on 16 ears (15 patients) with the isolated congenital ossicular chain malformation who underwent endoscopic ossiculoplasty in our department from May 2017 to January 2019. Endoscopic exploratory tympanotomy was conducted to check the ossicular chain; at the same time, endoscopic ossiculoplasty was performed depending on intraoperative findings. Air-conduction thresholds, bone-conduction thresholds, and air-bone gaps (ABGs) were measured before and after surgery, and the hearing outcome was assessed at 6 months postoperatively.

RESULTS

The most common malformations of ossicular chain were the missing of the incus long process and stapes suprastructure. A serial assessment of the hearing status was conducted before and 6 months after surgery. It showed the mean postoperative pure-tone average (PTA) was significantly reduced, and the mean postoperative ABG was obviously closed, respectively (P < .001). The mean PTA gain was 36.3 ± 8.6 dB, and the ABG closure was 35.1 ± 8.3 dB; ABG closure to 20 dB or less and ABG closure to 10 dB or less were achieved in 14 cases (87.5%) and 5 cases (31.3%), respectively. No differences were observed in postoperative hearing outcome between type Ⅲ cases and type Ⅳ cases; however, cases with partial ossicular replacement prosthesis implantation showed a larger hearing gain (P = .049) and a higher proportion of postoperative ABG less than 10 dB (P = .021). No facial palsy and significant sensorineural hearing loss occurred; all patients completed the surgery without the need of canalplasty, and the chorda tympani nerve was preserved in all patients.

CONCLUSIONS

This research showed endoscopic surgery was effective in the diagnosis and management of isolated congenital ossicular chain malformation; the endoscopic ossiculoplasty provides an alternative method to manage congenital ossicular chain malformation, with comfortable hearing outcome and the advantage of excellent vision and less invasion.

Concurrent Occurrence of Congenital Ossicular Anomaly and Localized Cholesteatoma: Series of 10 Cases

OBJECTIVE

The objective of this study is to describe the clinical features, managements and outcomes of a rare coexistence of congenital ossicular anomaly and localized cholesteatoma. A literature review on these cases and each congenital disorder is also presented.

METHODS

A retrospective chart review was performed on patients diagnosed with congenital ossicular anomaly with concurrent localized cholesteatoma from 2008 to 2017. Clinical data of these patients were collected.

RESULTS

A total of 10 patients were identified. All patients presented with unilateral hearing loss. Pure-tone audiometry showed conductive hearing loss in all affected ears with an average air conduction (AC) threshold of 59 dB. High-resolution computed tomography scans of the temporal bone diagnosed ossicular anomaly for 90% (9/10); however, only 50% (5/10) had a diagnosis of localized cholesteatoma. A transcanal exploratory tympanotomy under the microscope was performed to discover whether the localized tiny-sized cholesteatoma around the ossicular chain did not have direct contact with the ossicular chain, which could be diagnosed as congenital cholesteatoma. We removed the localized cholesteatoma and reconstructed the ossicular chain in each patient. All localized cholesteatomas were found in the posterior-superior quadrant of the middle ear. Ossicular chain anomalies were associated with the incus and/or the stapes in all cases. Hearing improvement was achieved in each of the 6 patients who were followed up postoperatively, with an average AC threshold of 35 dB. The clinical features of congenital ossicular anomaly with concurrent congenital cholesteatoma were compared with those of each congenital disorder. The pathogenesis of each condition was also discussed.

CONCLUSIONS

Congenital ossicular anomaly with concurrent congenital cholesteatoma is rare. It shares similar clinical features with congenital ossicular anomaly occurring alone, therefore awareness should be raised for a possible concurrent congenital cholesteatoma which was easy to miss in the diagnosis (50%) by the radiologist. A patient's hearing level can be improved by removal of the cholesteatoma and reconstruction of the ossicular chain. Localized cholesteatoma does not usually show residuals or recurrence.

The effect of age on ossiculoplasty results: A retrospective evaluation of 60 cases

OBJECTIVE

There are only a few studies evaluating ossiculoplasty results in the pediatric age group. Although the effect of different factors on the results of ossiculoplasty is investigated, the effect of age on ossiculoplasty results is not known. In this study, the effect of age on ossiculoplasty results has been investigated.

METHODS

This retrospective clinical study was performed in 60 patients (30 female, 30 male; mean age 15.5±14.3 years, range 9-57 years) who underwent ossiculoplasty. The cases were divided into two groups according to their age. Group A consisted of pediatric cases younger than 18 years of age and group B consisted of adult subjects (>18 years). The comparison of the groups was made by taking into consideration the air-bone gap in the 3rd and 12th weeks of the pre- and postoperative period.

RESULTS

There was no statistically significant difference between preoperative air-bone gaps of the groups (p=0.086). In the third postoperative month, the air-bone gap gain of group A was statistically significantly higher than group B (p=0.0001). The air-bone gap gain of group A was significantly higher than group B in the postoperative 12th month (p=0.026). The air-bone gap gain of the patients with malleus in group A and group B was higher in the postoperative 3rd month than in the patients without malleus (all p values <0.05). There was no statistically significant difference between the air-bone gap gain in patients with the stapes suprastructure and the air-bone gap gain of the patients without stapes suprastructure in group A and group B in the postoperative 3rd month (p values >0.05).

CONCLUSION

The results of ossiculoplasty were found better in the pediatric age group. We think that ossiculoplasty should be carried out without delay in the pediatric age group.

Influence of ossicular chain malformation on the performance of round-window stimulation: A finite element approach

As a novel application of implantable middle ear hearing device, round-window stimulation is widely used to treat hearing loss with middle ear disease, such as ossicular chain malformation. To evaluate the influence of ossicular chain malformations on the efficiency of the round-window stimulation, a human ear finite element model, which incorporates cochlear asymmetric structure, was constructed. Five groups of comparison with experimental data confirmed the model’s validity. Based on this model, we investigated the influence of three categories of ossicular chain malformations, that is, incudostapedial disconnection, incus and malleus fixation, and fixation of the stapes. These malformations’ effects were evaluated by comparing the equivalent sound pressures derived from the basilar membrane displacement. Results show that the studied ossicular chain malformations mainly affected the round-window simulation’s performance at low frequencies. In contrast to the fixation of the ossicles, which mainly deteriorates round-window simulation’s low-frequency performance, incudostapedial disconnection increases this performance, especially in the absence of incus process and stapes superstructure. Among the studied ossicular chain malformations, the stapes fixation has a much more severe impact on the round-window stimulation’s efficiency. Thus, the influence of the patients’ ossicular chain malformations should be considered in the design of the round-window stimulation’s actuator. The low-frequency output of the round-window simulation’s actuator should be enhanced, especially for treating the patients with stapes fixation.

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.