Cochlear implant and congenital cholesteatoma

BACKGROUND

The occurence of cholesteatoma and cochlear implant is rare. Secondary cholesteatomas may develop as a result of cochlear implant surgery. Primarily acquired cholesteatoma is not typically associated with congenital sensorineural hearing loss or cochlear implant in children. The occurrence of congenital cholesteatoma during cochlear implant surgery has never been reported before, partly because all patients are preoperatively submitted to imaging studies which can theoretically exclude the disease.

CASE PRESENTATION

We have reported a rare case of congenital cholesteatoma, found during sequential second side cochlear implantation in a 3-year-old child. The child underwent a computed tomography (CT) scan and magnetic resonance imaging (MRI) at 12 months of age, before the first cochlear implant surgery, which excluded middle ear pathology. The mass was removed as an intact pearl, without visible or microscopic violation of the cholesteatoma capsule. All the areas where middle ear structures were touching the cholesteatoma were vaporized with a laser and the cochlear implant was inserted uneventfully. Further follow-up excluded residual disease.

CONCLUSION

We believe that primary, single stage placement of a cochlear implant (CI) with simultaneous removal of the congenital cholesteatoma can be performed safely. However, to prevent recurrence, the capsule of the cholesteatoma must not be damaged and complete laser ablation of the surface, where suspicious epithelial cells could remain, is recommended. In our opinion, cholesteatoma removal and cochlear implantation should be staged if these conditions are not met, and/or the disease is at a more advanced stage. It is suspected, that the incidence of congenital cholesteatoma in pediatric CI candidates is much higher that in average pediatric population.

Diagnostic value of matrix metalloproteinase 9 and tissue inhibitor of matrix metalloproteinases 1 in cholesteatoma

OBJECTIVES

Matrix metalloproteinase 9 (MMP-9), able to degrade type IV collagen, plays a key role in inflammatory cell migration as well as in the destructive behaviour of cholesteatoma. The aim of our study was to compare the expression of MMP-9 and TIMP-1 in cholesteatoma tissue and in the concentrations in serum and plasma concentrations.

MATERIAL AND METHODS

Twenty five adult patients suffering from cholesteatoma (a study group) were included in the study. A comparison group consisted of 25 adult patients admitted to hospital due to nasal septum deviation. MM-9 and TIMP-1 serum and plasma concentrations as well as proteins' expressions in cholesteatoma tissues (study group) and normal retroauricular skin specimens (control group) were evaluated. MMP-9 and TIMP-1 concentrations were measured using enzyme-linked immunosorbent assay (ELISA). Cholesteatoma tissues and normal retroauricular skin specimens were evaluated immunohistochemically.

RESULTS

In the study and a comparison groups, MMP-9 and TIMP-1 concentrations were similar with no significant difference within the groups. In cholesteatoma tissues, the expression of the investigated enzyme and its inhibitor was higher than in normal skin specimens, limited mostly to cholesteatoma perimatrix.

CONCLUSION

Cholesteatoma may be limited to the middle ear or parts of the temporal bones. Our findings suggest better clinical usefulness of MMP-9 and TIMP-1 expression in cholesteatoma tissues than either serum or plasma levels of these proteins. It might suggest that the higher the expression of MMP-9 the stronger the inflammation -accompanied cholesteatoma.

Fluoroscopically Assisted Cochlear Implantation

HYPOTHESIS

Real-time intraoperative fluoroscopy is a useful adjunct to cochlear implantation in selected cases. The advantages include the avoidance of complications such as extracochlear array placement, intrameatal array insertion, and avoidance of significant bending or kinking. This is particularly useful when implanting a severely abnormal cochlea.

BACKGROUND

The technique was initially developed for laboratory study of electrode prototypes in cadaver temporal bones to evaluate insertion dynamics and mechanisms of intracochlear trauma. The technique was subsequently adapted for use in live surgeries.

METHODS

Live surgeries were performed using fluoroscopic guidance on nine patients.

RESULTS

Five patients were implanted with the Nucleus 24 RCS during preclinical trials. Two patients with severe cochlear malformations were implanted with a Nucleus CI24M straight array. Two patients with severe cochlear ossification were implanted with the Nucleus CI24 double array. Appropriate insertions were achieved without electrode damage in all cases.

CONCLUSIONS

Intraoperative fluoroscopy is a useful adjunct to cochlear implantation, which can be performed with minimum risk to the patient and operating room staff if the outlined precautions are taken. Intraoperative fluoroscopy is indicated in cases where the intracochlear behavior of the electrode array cannot be predicted, a condition encountered when implanting new electrode designs, cases with severely malformed inner ears, or cases of severe intraluminal obstruction requiring a double-array insertion.

The effect of betahistine on vestibular habituation: comparison of rotatory and sway habituation training

This study was designed to investigate the effect of histaminergic agonists and antagonists on the acquisition of vestibular habituation. The experimental animals, pigeons, were subjected to unilateral rotatory and sway habituation training sessions. The habituation of postural reflexes and post-rotatory head nystagmus was assessed. Vestibular habituation in the control group was achieved by adopting the kinetic reflex posture after approximately 9 training sessions, and after 10 and 14 training sessions, respectively for 50% reduction of the total number of beats (TNB) and the duration of post-rotatory head nystagmus. In the sway adaptation test control pigeons needed nearly 15 training sessions while pigeons receiving betahistine adapted after approximately 8 sessions. Administration of histamine and, most notably, betahistine accelerated the process, while both H1 and H2 antagonists (clemastine, cimetidine) tended to retard it, indicating a less significant contribution of H2 receptors. The cholinergic agent physostigmine strongly retarded habituation while the anticholinergic agent scopolamine markedly accelerated it. In addition the adrenomimetic agent ephedrine also accelerated habituation while the adrenolytic agent droperidol retarded reduction of nystagmus beats. The results indicate that histaminergic receptors play a significant role in the vestibular habituation mechanism but are intricately involved with other types of receptors. Betahistine is clearly the agent of choice for attenuating vestibular effects.