Stapesfixation bei Kindern

Optical coherence tomography of the oval window niche

OBJECTIVE

Optical coherence tomography was used to study the stapes footplate, both in cadaveric temporal bones and during middle-ear surgery.

MATERIALS AND METHODS

Optical coherence tomography was conducted on five temporal bone preparations (from two children and three adults) and in eight patients during middle-ear surgery. A specially equipped operating microscope with integrated spectral domain optical coherence tomography apparatus was used for standard middle-ear surgical procedures.

RESULTS

This optical coherence tomography investigation enabled in vivo visualisation and documentation of the annular ligament, the different layers of the footplate and the inner-ear structures, both in non-fixed and fixed stapes footplates. In cases of otosclerosis and tympanosclerosis, an inhomogeneous and irregularly thickened footplate was found, in contrast to the appearance of non-fixed footplates. In both fixed and non-fixed footplates, there was a lack of visualisation of the border between the footplate and the otic capsule.

CONCLUSIONS

Investigation of the relatively new technology of optical coherence tomography indicated that this imaging modality may assist the ear surgeon to assess the oval window niche intra-operatively.

[First experiences with a new nickel-titanium piston with a shape memory feature]

BACKGROUND

The aim of this study was to describe a new stapes prosthesis with memory characteristics for wire crimping (SMart-Piston).

PATIENTS AND METHODS

This technique was used in 15 patients (mean age 43.4 years; range 28-71) undergoing routine stapes surgery. SMart-Piston prostheses with a shaft diameter of 0.5 mm and length ranging from 4.25-4.5 mm were used. Heat induced wire crimping was performed by CO2 laser in five patients, and by bipolar diathermy forceps in ten patients. In 15 patients, postoperative audiological testing was performed at an average 21.9 days and in another 10 again after 435 days following surgery.

RESULTS

The median observed air-bone-gap (ABG) postoperatively was 8.7 dB+/-7.7 dB. A total of 73% of all patients had an ABG of 10 dB or less, and all patients had less than 20 dB. In the ten patients controlled after 435 days, the ABG was 4.4 dB+/-2.4 dB. It was lower than 10 dB in all individuals.

DISCUSSION

A critical point in every stapes surgery, the prosthesis fixation to the incus, is greatly facilitated by this novel technique. Long-term results in a larger group of patients are pending.

Fixation of the Stapes Footplate in Children: A Clinical and Temporal Bone Histopathologic Study

OBJECTIVE

To clarify the anatomic characteristics, cause, and surgical outcomes relating to fixation of the stapes footplate in children.

STUDY DESIGN

Retrospective case review and four-center histopathologic study of temporal bones.

SETTING

Tertiary referral center.

PATIENTS

We reviewed charts and histologic specimens from 12 children, aged 7 to 13 years, who underwent surgery for footplate fixation. We also studied stapes footplates in 288 temporal bones from 181 children ranging from newborn (20-44 weeks of gestation) to 13 years of age.

MAIN OUTCOME MEASURE

Anomalies of the stapes footplate in children.

RESULTS

The average age of diagnosis of hearing loss was 6.6 years. Criteria for a diagnosis of otosclerosis were progression of a conductive hearing loss and an intraoperative finding of fixation of the anterior stapediovestibular joint in five patients. In contrast, a nonhomogeneous, thickened, fixed footplate and the absence of an annular ligament were indicators of congenital fixation in six children. In one child, there was neither new bone from the otic capsule nor any obvious otosclerotic foci. In the temporal bone study, 17 of 181 (9.4%) children had anomalies of the stapes footplates, with ankylosis in 4 (2.2%). In two subjects (1.1%), there was an otosclerotic focus not in contact with the stapes footplate.

CONCLUSION

Children younger than 6 years with various congenital anomalies are more likely to have congenital footplate fixation, which will present intraoperatively as a thickened footplate with a partial or absent annular ligament. Children older than 6 years with progressive conductive hearing loss are more likely to have otosclerosis, which presents as fixation of the anterior stapediovestibular joint. The difference in surgical outcomes is probably related to different degrees of footplate abnormality.