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[Clinical relevance of developmental changes of the endolymphatic sac]
J Ussmüller1, M Sanchez-Hanke, R Leuwer
1Klinik und Poliklinik für Hals-Nasen-Ohrenheilkunde, Universitätsklinikum Hamburg-Eppendorf. ussmueller@uke.uni-hamburg.de
Background:
Outcome of endolymphatic sac shunt surgery crucially depends on endolymphatic sac morphology. The intraoperative finding of a fibrotic sac, e.g., will lead to therapy-failure. Aim of the present study was to determine possible developmental changes in endolymphatic sac morphology which could imply, that a shunt operation should not be undertaken in older age.
Method:
46 histological temporal bone serial sections were examined. All sections were taken from the "Wittmaack Temporal Bone Collection". All specimens were obtained from patients with morphologically healthy ears, especially without a history of Menière's disease or other kinds of vertigo.
Results:
During the fetal period the endolymphatic sac is a wide cavity that is surrounded by immature embryonal connective tissue. In older age this cavity gradually shrinks, leading to stenosis in about 80% of the cases. The endolymphatic duct, however, remains open.
Conclusion:
The increasing fibrosis of the endolymphatic sac is part of the natural involution of the inner ear. It constitutes a natural limitation for the outcome of endolymphatic sac shunt surgery in the elderly.