Surgical and clinical confirmation of temporal bone CT findings in patients with otosclerosis with failed stapes surgery

Surgical decision-making in superior canal dehiscence syndrome with concomitant otosclerosis

OBJECTIVE

The diagnosis and management of Superior Canal Dehiscence Syndrome (SCDS) with concomitant otosclerosis can be a challenge. Otosclerosis can mask SCDS symptoms and stapes surgery may reveal or exacerbate vestibular symptoms. Our aim is to present four cases of SCDS with concomitant otosclerosis and thereby informing the reader about the possibility of this dual occurrence and its implications for treatment.

CASES

Four patients with SCDS and concomitant otosclerosis are presented. Two patients underwent surgical treatment for both SCDS and otosclerosis and two patients opted for conservative management.

OUTCOMES

The main differences between surgically and non-surgically treated cases are the presence of autophony and pressure-induced vertigo and a more severe experience of symptoms in surgically treated cases. Surgically treated cases achieved a sizeable reduction in postoperative air-bone gap and resolution of vestibular symptoms.

CONCLUSION

The subjective severity of symptoms in combination with shared decision-making is key in determining the appropriate treatment plan for SCDS and concomitant otosclerosis.

Ultra-high-resolution CT of the temporal bone: The end of stapes prosthesis dimensional error and correlation with patient symptoms

PURPOSE

To describe the reliability of ultra-high-resolution computed tomography (UHR-CT) in the measurement of titanium stapes prostheses using manufacturer data as a reference.

MATERIALS AND METHODS

This retrospective study included patients treated by stapedectomy with titanium prostheses who underwent UHR-CT between January 2020 and October 2023. Images were acquired using an ultra-high-resolution mode (slice thickness: 0.25 mm; matrix, 1024 × 1024). Two radiologists independently evaluated the length, diameter, and intra-vestibular protrusion of the prosthesis. Post-operative air-bone gaps (ABGs) were recorded.

RESULTS

Fourteen patients were enrolled (mean age, 44.3 ± 13.8 [SD] years, 9 females), resulting in 16 temporal bone UHR-CTs. The exact length was obtained in 81.3 % (n = 13/16) and underestimated by 0.1 to 0.3 mm in the remaining 18.7 % (n = 3/16) CT scans for both readers (mean misestimation: -0.02 ± 0.06 [SD] mm, overall underestimation of 0.43 %). The exact diameter was reported in 75 % (n = 12/16) and 87.5 % (n = 14/16) of the CT scans for readers 1 and 2, respectively, and was off by 0.1 mm in all discrepancies (mean misestimation: 0.01 ± 0.04 [SD] mm, overall overestimation of 2.43 %). Intravestibular prosthesis protrusion was of 0.5 ± 0.43 [SD] mm (range: 0-1) and 0.49 ± 0.44 [SD] mm (range: 0-1.1) for readers 1 and 2, respectively, and did not correlate with ABGs (r = 0.25 and 0.22; P = 0.39 and 0.47 for readers 1 and 2, respectively). Intra and interobserver agreements were excellent.

CONCLUSION

UHR-CT provides 99.6 % and 97.6 % accuracy for prosthesis length and diameter measurements, respectively.

A Case of Vertigo with TORP in Inner Ear

This is a case of a patient with history of ear surgery who visited ENT outdoor, for continuous vertigo which used to get aggravated with loud noise, associated with hearing loss, persistent sensations of right-sided aural fullness/pressure and otalgia for last 2 years. He had history of tympanoplasty with ossiculoplasty using a TORP. On exploration under local anesthesia there was a displaced prosthesis into inner ear, upon removal of which symptoms and severity subsided exponentially.

Incidence of Concomitant Semicircular Canal Dehiscence With Otosclerosis

Objective

The concurrence of otosclerosis and superior semicircular canal dehiscence (SSCD) presents a diagnostic challenge and failure to differentiate between these 2 diagnoses results in mischaracterization and unsuccessful surgery. The objective of this study is to identify the incidence of SSCD in patients who have computed tomography (CT) evidence of otosclerosis.

Study Design

Retrospective chart review.

Setting

Tertiary referral hospital.

Patients

Adults with CT scan of the temporal bone diagnosed with radiological unilateral or bilateral fenestral otosclerosis from January 1995 to April 2018.

Methods

Retrospective review of patient imaging from a multi-center tertiary-referral health system from January 1995 to April 2018. Imaging was reviewed to quantify the incidence of SSCD among patients with CT-diagnosed bilateral fenestral otosclerosis. Poor quality imaging was excluded from review.

Results

One-thousand two-hundred eight patients (1214 CT scans) were identified with otosclerosis, of which 373 were diagnosed with fenestral otosclerosis (663 ears) with imaging of sufficient quality for review. This population was predominantly female (57.2%) with bilateral fenestral otosclerosis (78%). Of these, 23 ears (3.5%) had definitive evidence of SSCD, with an additional 15 ears (2.3%) with possible radiographic evidence of SSCD. There was no significant difference in laterality between the SSCD and otosclerosis.

Conclusions

Among 373 patients with fenestral otosclerosis per CT temporal bone imaging at a tertiary referral hospital, as many as 8.3% of patients had radiographic evidence of SSCD. Given this incidence, it continues to be important to consider SSCD when diagnosing and treating otosclerosis.

Role of Radiologic Imaging in Otosclerosis

Purpose of Review

To review the role of imaging in otosclerosis with an emphasis on pre- and post-operative imaging evaluation.

Recent Findings

Pre-operative CT imaging can help define the extent of bone involvement in otosclerosis and may help avoid surgical complications due to variant anatomy or unsuspected alternative causes of conductive hearing loss. In patients with recurrent hearing loss after surgery, CT imaging can clarify prosthesis position and re-assess anatomy.

Summary

CT imaging complements otologic exam and audiometry findings in patients with suspected otosclerosis, for pre-operative planning, and post-operative assessment for patients with recurrent symptoms.

[A case of obliteration of a round window in otosclerosis]

The article presents a brief review of the literature on the anatomy and physiology of the round window (RW) niche, the causes of occlusion, the diagnosis of this pathology, the features of auditory disorders and tactics when it is detected in patients with otosclerosis (OS). A clinical case of diagnosis and effective surgical treatment for obliteration of RW in a patient with advanced OS, which occurred in 2019 in 0.7% of cases, is described. Removal of RW niche obliteration was carried out with a curette and microcresis by smoothing the canopy over RW until partial visualization of the secondary membrane. It was this stage of the operation that made it possible to restore the normal hydrodynamics of the inner ear fluids and contributed to a functional result. Thus, the diagnosis of RW obliteration in patients with OS is difficult, but possible when using computed tomography of the temporal bones and assessing the mobility of the RW membrane or analyzing changes in hearing at the end of the operation, if it is performed under local anesthesia. The simultaneous performance of stapedoplasty and the removal of bone obliteration of RW makes it possible to safely achieve functional rehabilitation in patients with OS.

Radiological evaluation of the postsurgical middle ear

OBJECTIVE

The radiological evaluation of the postsurgical middle ear is complex due to the intricate anatomy of this region and the wide variety of procedures and materials used iin middle ear surgery. Knowledge of these factors will enable normal postsurgical changes to be differentiated from complications. This article describes the most common surgical procedures in the middle ear, their indications, and the normal radiological appearance after these procedures. It reviews the most common causes of failure in stapes surgery, in surgery for chronic otitis media, and in surgery for cholesteatoma, suggesting the best imaging method to assess the middle ear in each case.

CONCLUSION

Computed tomography enables the evaluation of prostheses and the aeration of the cavities, whereas magnetic resonance imaging makes it possible to characterize the possible occupation of the cavities and is the technique of choice for the follow-up of closed mastoidectomy for cholesteatomas.

Radiological evaluation of the postsurgical middle ear

OBJECTIVE

The radiological evaluation of the postsurgical middle ear is complex due to the intricate anatomy of this region and the wide variety of procedures and materials used iin middle ear surgery. Knowledge of these factors will enable normal postsurgical changes to be differentiated from complications. This article describes the most common surgical procedures in the middle ear, their indications, and the normal radiological appearance after these procedures. It reviews the most common causes of failure in stapes surgery, in surgery for chronic otitis media, and in surgery for cholesteatoma, suggesting the best imaging method to assess the middle ear in each case.

CONCLUSION

Computed tomography enables the evaluation of prostheses and the aeration of the cavities, whereas magnetic resonance imaging makes it possible to characterize the possible occupation of the cavities and is the technique of choice for the follow-up of closed mastoidectomy for cholesteatomas.

Decision Making in Patients With Concomitant Otosclerosis and Superior Semicircular Canal Dehiscence: A Systematic Review of the Literature

OBJECTIVE

Concomitant otosclerosis (OTS) and superior semicircular canal dehiscence (SSCD) is a rare, but difficult-to-identify and treat diagnosis. A systematic review of the literature was performed to analyze the diagnostic and therapeutic approaches of concurrent OTS and SSCD cases and to identify possible factors that may help in predicting the surgical outcome.

DATA SOURCES

PubMed, Scopus, Medscape, Ovid databases.

STUDY SELECTION

Studies showing diagnosis of OTS documented by audiometric test with or without associated radiological signs (computed tomography), and concomitant diagnosis of SSCD, documented at least by high-resolution computed tomography (and possibly supported by neurophysiological testing) were included. Both surgically treated and untreated patients were considered for data analysis.

DATA EXTRACTION

The general characteristics of each study were recorded, when available. Clinical, audiological, vestibular testing, surgical, and radiological data were extracted from the published case reports and series, and recorded on a database. For each case, the diagnostic steps that confirmed OTS and concomitant SSCD in the same ear were extracted.

DATA SYNTHESIS

Twelve studies were included in the review and 18 cases affected simultaneously by the 2 conditions were extracted and analyzed. Seven of 12 ears (58.3%) undergoing stapes surgery experienced a hearing improvement. In four (33.3%) cases, vestibular symptoms (with or without associated acoustic symptoms) of SSCD were unmasked or worsened by stapes surgery.

CONCLUSIONS

A reliable preoperative diagnosis of the two concomitant conditions is possible with a proper interpretation of clinical signs, audiometric, and vestibular testing, in association with the radiologic assessment. Despite that the length and the location of the dehiscence may guide the surgical decision, definitive conclusions regarding the appropriate indications for surgical treatment cannot be drawn due to the limited number of cases with adequate data reported in the literature.

A Case Series of Patients With Concurrent Otosclerosis and Superior Semicircular Canal Dehiscence

OBJECTIVE

To describe the presentations and treatment results for patients with concurrent otosclerosis and superior semicircular canal dehiscence (SCD).

STUDY DESIGN

Retrospective case series and literature review.

SETTING

Tertiary academic medical center.

PATIENTS

Patients with concurrent diagnoses of otosclerosis (radiographically and/or surgically confirmed) and SCD (radiographically confirmed) in the same ear.

INTERVENTION(S)

Review of medical records.

MAIN OUTCOME MEASURE(S)

Clinical presentations, outcomes following stapedotomy.

RESULTS

Eight patients with 10 affected ears were identified. All patients presented with slowly progressive conductive hearing loss, normal otoscopy, absent acoustic reflexes, and without other symptoms of SCD syndrome. Seven patients were treated with stapedotomy and 1 with hearing aids. Of those treated with stapedotomy, a persistent conductive hearing loss was the most common hearing result. One patient had near-complete closure of their air bone gap. None had a profound sensorineural hearing loss. Four patients had unmasking of SCD symptoms.

CONCLUSIONS

The clinical and audiometric presentations of patients with concurrent otosclerosis and SCD are often indistinguishable from those of patients with only otosclerosis. Computed tomography of the temporal bone is the only way to identify concurrent SCD. Stapedotomy in these patients typically results in a persistent conductive hearing loss, though 14 to 33% of patients experience near-complete closure of their air bone gap. SCD symptoms are unmasked in 57 to 63% of patients who undergo stapedotomy. Further work is needed to delineate the utility of routine preoperative computed tomography scan in otosclerosis patients, and to identify prognostic factors for patients with concurrent otosclerosis and SCD who wish to undergo stapedotomy.

Postoperative Imaging of the Temporal Bone

The anatomy of the temporal bone is complex, and postoperative imaging evaluation of this bone can be challenging. Surgical approaches to the temporal bone can be categorized didactically into tympanoplasty and ossicular reconstruction, mastoidectomy, and approaches to the cerebellopontine angle and internal auditory canal (IAC). In clinical practice, different approaches can be combined for greater surgical exposure. Postoperative imaging may be required for follow-up of neoplastic lesions and to evaluate unexpected outcomes or complications of surgery. CT is the preferred modality for assessing the continuity of the reconstructed conductive mechanism, from the tympanic membrane to the oval window, with use of grafts or prostheses. It is also used to evaluate aeration of the tympanic and mastoid surgical cavities, as well as the integrity of the labyrinth, ossicular chain, and tegmen. MRI is excellent for evaluation of soft tissue. Use of a contrast-enhanced fat-suppressed MRI sequence is optimal for follow-up after IAC procedures. Non-echo-planar diffusion-weighted imaging is optimal for detection of residual or recurrent cholesteatoma. The expected imaging findings and complications of the most commonly performed surgeries involving the temporal bone are summarized in this review. Online supplemental material is available for this article. ^©RSNA, 2021.

Imaging Studies in Otosclerosis: An Up-to-date Comprehensive Review

Introduction  Otosclerosis is a primary osteodystrophy of the otic capsule, frequently responsible for acquired hearing loss in adults. Although the diagnostic value of imaging investigations in otosclerosis is debatable, they might still be employed with different goals within the context of the disease.

Objectives  The present paper aims to review the most recent literature on the use of imaging studies in otosclerosis for the most varied purposes, from routine application and differential diagnosis to prognostic prediction and investigation of surgical failure.

Data Synthesis  The diagnosis of otosclerosis is usually clinical, but computed tomography (CT) is paramount in particular cases for the differential diagnosis. The routine use, however, is not supported by strong evidence. Even so, there is growing evidence of the role of this method in surgical planning and prediction of postoperative prognosis. In specific scenarios, for example when superior semicircular canal dehiscence (SSCD) syndrome is suspected or in surgical failure, CT is crucial indeed. Magnetic resonance imaging (MRI), however, has limited – although important – indications in the management of individuals with otosclerosis, especially in the evaluation of postoperative complications and in the follow-up of medical treatment in active ostosclerosis.

Conclusion  Imaging studies have a broad range of well-established indications in otosclerosis. Besides, although the routine use of CT remains controversial, the most recent papers have shed light into new potential benefits of imaging prior to surgery.

Involvement of the Internal Auditory Canal in Subjects With Cochlear Otosclerosis: A Less Acknowledged Third Window That Affects Surgical Outcome

OBJECTIVE

To investigate the effects of cavitating lesions involving the internal auditory canal (IAC) in subjects with cochlear otosclerosis with regard to poststapedotomy hearing outcome.

STUDY DESIGN

Retrospective study.

SETTING

Tertiary referral center.

PATIENTS

A retrospective chart review of 134 subjects with otosclerosis treated from January 2011 to June 2017 at Seoul National University Bundang Hospital was conducted. Sixteen subjects (23 ears) with temporal bone computed tomography (TBCT)-confirmed cochlear otosclerosis who underwent stapedotomy were included in the study.

MAIN OUTCOME MEASURES

Pure tone audiometry (PTA) (i.e., air and bone conduction; AC and BC, respectively) thresholds and air-bone gap (ABG), measured at 6 months postoperatively were compared between cochlear otosclerosis with and without IAC involvement (IAC group and non-IAC group, respectively).

RESULTS

A total of 14 of 23 ears showed involvement of the IAC. There were no significant differences in age, side of otosclerosis, or preoperative hearing threshold between the two groups. The mean postoperative AC and BC thresholds and ABG of the IAC group were significantly poorer (45.7 dB, 33.8 dB, and 11.8 dB, respectively) than those of the nonIAC group (24.1 dB, 20.0 dB, and 4.1 dB, respectively).

CONCLUSIONS

Cochlear otosclerosis with cavitating lesions involving the IAC showed significantly poorer postoperative audiological outcomes than those without any cavitating lesion. Cavitation extending to the IAC may act as a third window providing a route for sound energy shunting, and thus precluding successful hearing outcome in some subjects with cavitating otosclerosis after stapedotomy.

Failure to close the gap: Concomitant superior canal dehiscence in otosclerosis patients

OBJECTIVE

Superior semicircular canal dehiscence (SSCD) causing conductive hearing loss with present reflexes is a known reason for stapes surgery failure. However, concomitant SSCD and otosclerosis occur rarely. We present a case series of SSCD diagnosed in positively identified otosclerosis patients.

METHODS

Retrospective review of clinical case series in two tertiary-referral neurotologic practices was performed. Clinical histories, operative findings, audiograms, and computed tomography (CT) images were reviewed for patients diagnosed with both SSCD and otosclerosis. Patients with present stapedial reflexes were excluded. Comprehensive literature review was performed.

RESULTS

Four cases were identified. Three reported improved hearing with partial or complete closure of the air-bone gap (ABG), including one patient with far-advanced otosclerosis. One patient had no improvement in pure tone average or ABG. One patient reported worsening of preoperative autophony and pulsatile tinnitus, but none developed new postoperative third-window symptoms. CTs demonstrated both SSCD and otosclerosis.

CONCLUSION

Failure to close the ABG in patients with positively identified otosclerosis intraoperatively may be due to SSCD as an occult concomitant diagnosis. SSCD should be considered as a possible cause of persistent conductive hearing loss after stapes surgery.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:1023-1027, 2020.

A Rare Cause of Stapedotomy Failure: When the Depth Marker Becomes a Locking Device: A Report on 2 Cases

We report 2 cases of stapes surgery failure due to the depth marker groove of the piston of a Big Easy titanium prosthesis getting caught at the edge of the stapedotomy hole. In the first case, the stapedotomy failure, detected peroperatively, was corrected by modifying the angulation of the shaft of the prosthesis. In the second case, the failure occurred after a delay during which scar tissue developed around the depth marker groove, hampering the movement of the prosthesis. The usual postoperative imaging did not detect this complication. The diagnosis was made during revision surgery and the condition was treated by enlarging the hole in the footplate. Alternatively, the use of a piston without a depth marker groove would have resolved the problem. Although a rare event, the possibility of stapes surgery failure due to the depth marker groove should not be overlooked.

Conductive hearing loss with a "dry middle ear cleft"-A comprehensive pictorial review with CT

Conductive hearing loss (CHL) commonly results from middle ear fluid and inflammation (otitis media). Less commonly in patients with CHL, the middle ear cleft is well aerated or 'dry' with absence of soft tissue or fluid clinically and on imaging. There are numerous causes for this but they can be clinically challenging to diagnose. This pictorial review aims to illustrate and discuss the CT features of both common and less common causes of CHL in patients with a "dry middle ear cavity".

Superior semicircular canal dehiscence with concomitant otosclerosis-A literature review and case discussion

Computed tomography scan should be performed as a routine before every stapes surgery, in order to exclude concomitant superior semicircular canal dehiscence, since no other clinical, audiological, or electro-physiological criteria are available to exclude concomitant superior semicircular canal dehiscence in the otosclerotic temporal bone.

Otosclerosis and Dysplasias of the Temporal Bone

Many bone dysplasias, some common and others rare, may involve the temporal bone causing conductive, sensorineural, or mixed hearing loss, vestibular dysfunction, or skull base foraminal narrowing, potentially affecting quality of life. Some conditions may affect only the temporal bone, whereas others may be more generalized, involving different regions of the body. High-resolution computed tomography may detect subtle osseous changes that can help define the type of dysplasia, and MR imaging can help define the degree of activity of lesions and potential associated complications.

Diagnosis of Superior Semicircular Canal Dehiscence in the Presence of Concomitant Otosclerosis

OBJECTIVE

To review three patients with concurrent otosclerosis and superior canal dehiscence identified before operative intervention and provide a practical diagnostic approach to this clinical scenario.

STUDY DESIGN

Retrospective patient series.

SETTING

Tertiary/quaternary referral center.

PATIENTS

Individuals with confirmed diagnoses of concurrent otosclerosis and superior semicircular canal dehiscence syndrome.

INTERVENTIONS

Detailed history and physical examinations were performed on these patients, as well as detailed audiovestibular testing and computed tomography imaging.

MAIN OUTCOME MEASURES

Establishing a clear diagnosis of concurrent otosclerosis and superior semicircular canal dehiscence syndrome using a thorough diagnostic approach.

RESULTS

Three patients presented with conductive hearing loss and normal tympanic membranes. When history and physical examination yielded suspicious third window symptoms/signs, more detailed audiovestibular testing and computed tomography scan imaging were performed. All three patients were ultimately identified to have concurrent otosclerosis and superior canal dehiscence. Conservative management was the option of choice for two of these patients (trial of a hearing aid) and surgical intervention was performed to treat the otosclerosis in the remaining patient.

Contemporary imaging of auditory implants

There have been significant advances in the diversity and effectiveness of hearing technologies in recent years. Implanted auditory devices may be divided into those that stimulate the cochlear hair cells (bone conduction devices and middle ear implants), and those that stimulate the neural structures (cochlear implants and central auditory implants). Contemporary preoperative and postoperative imaging may be used to help individualise implant selection, optimise surgical technique and predict auditory outcome. This review will introduce the concepts behind auditory implants, and explains how imaging is increasingly used to aid insertion and evaluation of these devices.

Transmastoid resurfacing versus middle fossa plugging for repair of superior canal dehiscence: Comparison of techniques from a retrospective cohort

Objective

To compare and contrast our experience with middle cranial fossa approach (MFR) and transmastoid approach with capping of the dehiscence (TMR) of superior semicircular canal dehiscence and to determine guidelines to help guide management of these patients.

Methods

All patients from 2005 to 2014 with symptomatic superior semicircular canal dehiscence syndrome with dehiscence demonstrated on CT scan of the temporal bone who underwent surgical repair and had a minimum 3 months of follow up. Surgical repair via the MFR or TMR, preoperative CT temporal bone, preoperative, and postoperative cervical vestibular evoked myogenic potential (cVEMP) testing and anterior canal video head thrust testing (vHIT). Success of repair was stratified as complete success, moderate success, mild success, or failure based on resolution of all symptoms, the chief complaint, some symptoms, or no improvement, respectively.

Results

A total of 29 ears in 27 patients underwent surgical repair of canal dehiscence. Complete or moderate success was seen in 71% of the MFR group compared to 80% of the TMR group. There were zero failures with the MFR group and no major intracranial complications. There were 2 failures out of 15 ears that underwent the TMR. Residual symptoms were most commonly vertigo or disequilibrium in the MFR and aural fullness or autophony in the TMR groups, respectively. MFR hospital stay was approximately 2 days longer. Average cVEMP threshold shifted 18 dB with surgical correction in the MFR group. A 29 dB average shift was seen in the TMR group. The MFR group had a significant reduction in their anterior canal gain compared to the TMR group.

Conclusions

TMR is a less invasive alternative to MFR. However, in our series, we have not seen any intracranial complications (aphasia, stroke, seizures, etc.) in our MFR patients. Interestingly, vestibular symptoms were better addressed than audiological symptoms by the TMR suggesting its usefulness as a less invasive option for patients with primarily vestibular complaints. Residual auditory symptoms in TMR patients may be due to the flow of acoustic energy from the superior canal to the mastoid cavity through an incompletely sealed third window.

Imaging Review of the Temporal Bone: Part II. Traumatic, Postoperative, and Noninflammatory Nonneoplastic Conditions

The first part of this review of the temporal bone discussed anatomy of the temporal bone as well as inflammatory and neoplastic processes in the temporal bone region (1). This second part will first discuss trauma to the temporal bone and posttraumatic complications. The indications for common surgical procedures performed in the temporal bone and their postoperative imaging appearance are then presented. Finally, a few noninflammatory nonneoplastic entities involving the temporal bone are reviewed. They are relatively uncommon diagnoses compared with infectious or inflammatory diseases. However, because patients present with symptoms that are either common (hearing loss) or distinctive (sensorineural hearing loss in a child), they are important for the radiologist to be aware of and recognize.