[Clinical relevance of developmental changes of the endolymphatic sac].

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.