Helical CT findings in patients who have undergone stapes surgery for otosclerosis

Fixed vs Measured Length of Stapes Prosthesis in Stapes Surgery

Aims The aim of this study is to assess the relationship between the prosthesis length and the outcome of the primary stapes surgery in patients with otosclerosis. Material and Methods This was a retrospective cohort study. We reviewed medical records of 218 patients between January 2015 and August 2020 in two different referral centers. It was conducted in two hospitals by two different well experienced otologic surgeons that one of them believes in fixed length (4.75 mm) of stapes prosthesis (group A) and, the other one believes in measuring the distance between the footplate and incus long process to choose the proper length of prosthesis (group B). The surgery success rates and complications between these two groups were compared 3 months postoperatively. Results Mean age, preoperative bone conduction (BC) audiometric threshold and air-bone gap, postoperative BC and air-bone gap were similar in both groups (All p > 0.05). Vertigo frequency was not significantly different between the two groups (p = 0.303). There were no significant differences regarding the number of favorable postoperative outcomes between group A and B (70 (97.2%) vs. 142(97.3%) respectively) (p = 0.632). Conclusion This study found no significant difference regarding the hearing outcomes between fixed length vs measured length of stapes prosthesis.

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 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.

Intravestibular Stapes Prosthesis Protrusion Causing Post Stapedectomy Vertigo

Post stapedectomy vertigo is most often a self-limiting postoperative complication. Sometimes vertigo occurs years after operation and different etiologies, non-surgically as well as related to previous surgery, have to be excluded. High resolution CT of the temporal bone can be of help, as in this case report, in which the images showed intravestibular stapes prosthesis protrusion.

The Relationship between Stapes Prosthesis Length and Rate of Stapedectomy Success

OBJECTIVES

To identify whether measurement of the prosthesis length is mandatory in patients requiring otosclerosis surgeries and to assess their postoperative audiometric outcomes. In addition, evaluation of prosthesis length used in revision compared to primary stapedectomy was carried out.

STUDY DESIGN

Case series with chart review.

METHODS

Chart review of 393 patients undergoing primary (321) versus revision stapedectomy (72) was performed in a tertiary referral center. The indication for surgery was the presence or persistence/recurrence of an air-bone gap (ABG) greater than 20 dB. Air and bone conduction thresholds (ACT and BCT, respectively), ABG as well as pure tone averages (PTAs) were determined for all patients, and the results were compared preoperatively and postoperatively.

RESULTS

Prosthesis length used ranged from 3.0 to 6.0 mm without differences between primary and revision groups. Of the revision surgeries, 62.5% were stapedectomies versus stapedotomies (P < 0.001). Patients showed significant decrease in speech discrimination score, with increased air and bone conduction thresholds as well as mean ABG and PTA before the revision surgeries as a first procedure failure. Prosthesis length changes occurred in 73.5% of the cases, with an average absolute change of 0.55 mm. Prosthesis length did not affect postoperative audiometric results between primary and revision groups, in all surgeries combined. When grouping stapes surgery into accurately versus inaccurately measured incus-footplate distance, significant differences were observed in prosthesis length employed (P < 0.01). Hearing outcomes were also better in the group in which an accurately measured prosthesis was chosen, as opposed to “standard-length” prosthesis.

CONCLUSIONS

This study corroborates postoperative success rates of revision surgeries, which show smaller improvements in hearing compared to a primary intervention. Accurate intra-operative measurement of prosthesis length was correlated with better audiometric results postoperatively.

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

BACKGROUND AND PURPOSE

Prior descriptions of imaging after failed stapes procedures for otosclerosis predated currently available CT technology and/or failed to assess commonly used metallic implants. The purpose of this study was to correlate temporal bone CT findings with clinically and intraoperatively determined causes of surgical failure.

MATERIALS AND METHODS

All patients with otosclerosis undergoing stapedectomy between December 1999 and December 2010 were identified from a search of neurotology clinical records. Patients presenting because of failed stapes surgery and having temporal bone CT scans at the time of revision surgery or clinical evaluation were included. Imaging and clinical records were retrospectively evaluated by a medical student, radiology resident, and senior neuroradiologist. Stapes prosthesis complications and relevant anatomic CT findings were correlated to clinical and intraoperative findings.

RESULTS

Twenty-two of 340 patients met inclusion criteria. Temporal bone CT findings were correlated to intraoperative findings in 17 of 22 patients and to clinical findings in 5 of 22 patients. Surgically confirmed abnormalities included 7 of 7 incus erosions, 3 of 6 piston re-sizings, 3 of 5 granulation tissues, 3 of 5 prosthesis disconnections, 3 of 4 obliterative otosclerosis, 2 of 2 oval window dislocations, and 1 labyrinthine ossificans. Clinically confirmed abnormalities included 2 cases each of superior semicircular canal dehiscence, and wrong piston size, and 1 each of piston disconnection, labyrinthine ossificans, and intravestibular footplate.

CONCLUSIONS

CT evaluation in the setting of failed stapes surgery is challenging. Many postoperative complications such as piston migration, incus necrosis, and overt vestibular penetration are well recognized on temporal bone CT. Of particular note, superior semicircular canal dehiscence is an important contraindication to stapes surgery.

Computed tomographic imaging of stapes implants

HYPOTHESIS

Computed tomographic (CT) imaging of stapes prostheses is inaccurate.

BACKGROUND

Clinical situations arise in which it would be helpful to determine the depth of penetration of a stapes prosthesis into the vestibule. The accuracy of CT imaging for this purpose has not been defined. This study was aimed to determine the accuracy of CT imaging to predict the depth of intrusion of stapes prostheses into the vestibule.

METHODS

The measurement of stapes prostheses by CT scan was compared with physical measurements in 8 cadaveric temporal bones.

RESULTS

The depth of intrusion into the vestibule of the piston was underestimated in specimens with the fluoroplastic piston by a mean of 0.5 mm when compared with the measurements obtained in the temporal bones. The depth of penetration of the stainless steel implant was overestimated by 0.5 mm when compared with that in the temporal bone.

CONCLUSION

The type of implant must be taken into consideration when estimating the depth of penetration into the vestibule using CT scanning because the imaging characteristics of the implanted materials differ. The position of fluoroplastic pistons cannot be accurately measured in the vestibule. Metallic implants are well visualized, and measurements exceeding 2.2 mm increase the suspicion of otolithic impingement. Special reconstructions along the length of the piston may be more accurate in estimating the position of stapes implants.

[Significance of computed tomography evaluation before revision stapes surgery]

BACKGROUND

Stapedectomy and, more recently, stapedotomy have been widely accepted as the primary surgical techniques to improve conductive hearing in patients suffering from otosclerosis. Unsuccessful outcomes are infrequent, but revision surgery may become necessary. We have analyzed the value of computed tomography (CT) scanning following unsuccessful stapes surgery.

PATIENTS AND METHODS

In a total of 37 CT scans, the depth of insertion, angle between prosthesis and footplate, location of prosthesis within the oval niche, visibility of the prosthesis, dehiscence of the superior semicircular canal, and extent of otospongiotic foci were evaluated and compared with the audiometric results.

RESULTS

There was no significant correlation between CT parameters and audiologic results, except for patients with cochlear otosclerosis or lateral dislocation of the piston. One previously unknown dehiscence of the superior semicircular canal was diagnosed. Otospongiotic foci were seen in 13 ears (35%).

CONCLUSION

Displacements of the stapes piston and rare causes for an insufficient result, such as a dehiscence of the superior semicircular canal, can be diagnosed accurately by CT. However, correlation between the audiologic results and the findings on CT scans was possible in only a few cases. Nevertheless, CT scans provide additional information for surgical planning in revision stapes surgery and may become increasingly important to reduce unanticipated intraoperative risks; they may even guide the surgeon not to perform unnecessary revision surgeries.

Déhiscence du canal semi-circulaire antérieur mimant une otospongiose: intérêt de l'imagerie

OBJECTIVES

To emphasize the role of computerized tomography (CT) in the etiologic work-up of stapes surgery failure.

MATERIAL AND METHODS

Helical high resolution CT scan of the temporal bone with axial and coronal views and multiplanar reconstructions was performed in a patient who had undergone unsuccessful stapedectomy.

RESULTS

CT scan demonstrated a well located prosthesis, the absence of the radiological hallmarks of otosclerosis, and revealed a superior semicircular canal dehiscence (SSCD). The diagnosis of SSCD was retrospectively considered accountable for the preoperative clinical and audiometric presentation that had mimicked otosclerosis.

CONCLUSION

CT is the diagnostic test of choice in elucidating stapes surgery failure (with persistent or recurrent conductive hearing loss), whereas SSCD should be systematically considered among its causes.

[Middle ear cholesteatoma]

Cholesteatoma is a serious form of chronic otitis media. The aim of this paper is to present the state of the art of disease management, including recent data from the literature and the authors' derived from their Mentors' teaching, Professor Pierre Roulleau (Paris, France) and Professor Robert Charachon (Grenoble, France). The main recent advances concern the use of cartilage grafts to reconstruct the canal wall and/or tympanic membrane (allowing a significant reduction in residual cholesteatoma) and progress in medical imaging allowing more acute preoperative determination of extension of the cholesteatoma (in order to propose an optimally designed surgical technique) and a less invasive postoperative follow-up.

Imagerie des échecs et complications post-opératoires de la chirurgie de l’otospongiose

Otosclerosis (OS) is a dysplasia of the otic capsule located in most cases on the anterior margin of the oval window or fissula ante fenestrum. Progressive conductive hearing loss is the major clinical symptom, due to stapedovestibular ankylosis. Stapes surgery is the only effective treatment of OS, with excellent functional results in more than 90% of cases. However, failures and complications of the surgery may be observed. In theses cases, the etiologic work-up includes imaging evaluation (CT and MRI). Imaging findings are extremely useful in the therapeutic decision. Surgical failure represents 80% of the causes for surgical revision. The main causes of failure are: displacement of the prosthesis, fibrosis of the oval window, erosion of the long process of the incus, incudo-mallear dislocation, obliterative otosclerosis. CT is essential for diagnosis. MR imaging is rarely indicated in the work-up of surgical failures. Labyrinthine complications account for less than 20% of surgical revisions. Etiologies of labyrinthine complications are: intravestibular penetration of the prosthesis, perilymphatic fistula, intra-vestibular granuloma, labyrinthitis and intravestibular bleeding. CT and MRI are complementary for the work up of these complications.

Imaging of the windows of the temporal bone

Imaging of the window of the temporal bone has became an important tool in the analysis of hearing loss, vertigo, tinnitus in a context of trauma, malformation, otosclerosis, and chronic otitis media. A good knowledge of the anatomy and a good technical procedure are necessary for making an efficient diagnosis. The increased thickness of the footplate may be delineated in otosclerosis, chronic otitis media, malformation, when it is measured at 0.7 mm or more in horizontal computed tomography (CT) sections. The traumatic displacement of the stapes, particularly within the labyrinths, is easily diagnosed in horizontal CT section. Imaging of the round window is now very important for the detection of otosclerotic foci, congenital stenosis, and perilymphatic fistula with or without fracture. Magnetic resonance imaging (MRI) with the high-resolution T2 plays an important role in the detection of a small amount of fluid in the round window recess, confirming the traumatic perilymphatic fistula without fracture.