Evaluation of high-resolution CT after tympanoplasty

Three-dimensional imaging of active and passive middle ear prostheses using multislice computed tomography

OBJECTIVE

This study examined the explanatory power of 3-dimensional visualization of middle ear prostheses and to introduce this method as a supplementary diagnostic tool.

METHODS

Various prostheses were examined in vitro. Surface rendering and perspective volume-rendering techniques were compared with axial, curviplanar, and maximum intensity projection images. One hundred three patients with hearing difficulty underwent high-resolution computed tomography scanning. The 3-dimensional images of 41 patients after nonspecific middle ear surgery were compared with the tympanoscopic findings.

RESULTS

The PVR technique allowed the depiction of the smallest individual substructures of the prostheses. The evaluation of the prostheses' localization using PVR was significantly better than using maximum intensity projection (P < 0.001). Surface rendering showed no advantages over 2-dimensional imaging. Diagnostic findings of high-resolution computed tomography were comparable to tympanoscopy (specificity 100%, sensitivity 95.1%).

CONCLUSION

The 3D depiction facilitates the evaluation of middle ear prostheses fitting.

Stabilization technique for columella using trimmed autologous temporal fascia in type III and IV tympanoplasty--Muffler method

CONCLUSION

High success rates of recovery of hearing level in type III and IV tympanoplasty could be achieved by this stabilization technique for columella using trimmed autologous temporal fascia.

OBJECTIVE

The aim of this study was to evaluate a new stabilization technique for columella using trimmed autologous temporal fascia in type III and IV tympanoplasty.

PATIENTS AND METHODS

A total of 55 patients (21 male, 34 female, aged 4-85 years) with chronic otitis media (n=16) and cholesteatoma (n=39) underwent tympanoplasty using this new stabilization technique for columella. Thirty-one patients underwent type III tympanoplasty and 24 patients underwent type IV tympanoplasty. Forty-two patients underwent a staged operation and 13 patients underwent a single operation. The observation period was 3.5 years from 6 months after the last operation.

RESULTS

The overall success rates in type III and IV tympanoplasty were 87.1% (27/31) and 83.3% (20/24), respectively. Two of eight patients for whom the procedure was unsuccessful underwent reoperation and they acquired good hearing.

Usefulness of delayed postcontrast magnetic resonance imaging in the detection of residual cholesteatoma after canal wall-up tympanoplasty

OBJECTIVES/HYPOTHESIS

Imaging takes an increasing place in the follow-up of patients who have undergone surgery for cholesteatoma, with computed tomography (CT) as the first line imaging technique. However, in case of complete opacity of the tympanomastoid cavities, CT is not able to differentiate residual cholesteatoma from postoperative scar tissue. The aim of this study was to assess the usefulness of magnetic resonance imaging (MRI) using delayed postcontrast T1-weighted images for the detection of residual cholesteatoma after canal wall-up tympanoplasty (CWU) in cases where CT was not conclusive.

STUDY DESIGN

Prospective study.

METHODS

MRI, with delayed postcontrast T1-weighted images (30-45 minutes after contrast injection), was performed before revision surgery in 41 consecutive patients who had undergone CWU for cholesteatoma and presenting with a nonspecific complete opacity of the mastoid bowl on CT. In all the cases, imaging results were compared with operative findings at surgical revision.

RESULTS

A residual cholesteatoma was found in 19 of 41 patients at revision surgery and was correctly detected on MRI in 17 patients. In the two remaining cases, cholesteatoma pearls smaller than 3 mm were not seen. There was no false-positive case. Statistics were as follows: sensitivity 90%; specificity 100%; positive predictive value 100%; negative predictive value 92%.

CONCLUSION

When postoperative CT is not conclusive because of complete opacity of the tympanomastoid cavities, MRI with delayed postcontrast T1-weighted images is a reliable additional technique for the detection of a residual cholesteatoma when its diameter is at least 3 mm.

Imaging of the postoperative middle ear

The aim of this article is twofold: (a) to present the principles and the indications of surgical treatment of middle ear pathologies; and (b) to review the imaging findings after middle ear surgery, including the normal postoperative aspects and imaging findings in patients presenting with unsatisfactory surgical results or with suspicion of postoperative complications. This review is intentionally restricted to the most common diseases involving the middle ear: chronic otitis media and otosclerosis. In these specific fields of interest, CT and MR imaging play a very important role in the postoperative follow-up and in the work-up of surgical failures and complications.

CT and MR imaging after middle ear surgery

This article describes the current value of imaging in patients after stapes surgery and surgery after chronic otitis media including cholesteatoma. Possibilities and limits of computed tomography (CT) and MRI are described and most important investigation parameters are mentioned. After otosclerosis surgery, CT is the method of first choice in detection of reasons for vertigo and/or recurrent hearing loss in the later postoperative phase. CT may show the position and condition of prosthesis, scarring around the prosthesis and otospongiotic foci. Sometimes, it gives indirect hints for perilymphatic fistulas and incus necrosis. MRI is able to document inner ear complications. CT has a high negative predictive value in cases with a free cavity after mastoidectomy. Localized opacities or total occlusion are difficult to distinguish by CT alone. MRI provides important additional information in the differentiation of cholesterol granuloma, cholesteatoma, effusion, granulation and scar tissue.