Can fetal ossicles be used as prosthesis in adults? A morphometric study

Abstract

Objectives: The tympanic cavity contains 3 small immovable bones, the malleus, incus and stapes. Extensive studies have been carried out on the morphometry of the ossicles. According to some scientists, in human beings the auditory ossicles reach there definitive size and shape in fetal periods and postnatal modifications are minimal, while there are certain studies which their contradict this claim. These contradictory claims prompted us to make an endeavor to find out the growth pattern of the ear ossicles and comparing the data with adults.

Methods: Twenty-two fetal cadavers of either sex, ranging in gestational ages between 24-40 weeks, were collected from local hospitals and 15 adult formalin-fixed cadavers in age groups of 20-30 years were taken. For the study, the fetuses were kept in 2 Groups of 24-28 weeks and 36-40 weeks. From the data obtained, the mean, standard deviation and percentage gain from one group to another in different dimensions of various parts of each ossicle was calculated.

Results: The age periods between 40 weeks (full term fetuses) and adults, revealed spurt in the growth of diameter of head of malleus (3%), width of short process of incus (2.7%), width of footplate (5.2%) and height of stapes (13%). These changes were insignificant in terms of acoustic transmission.

Conclusion: It is concluded that by the end of gestation, the ear ossicles develop morphometric features comparable to adults with no appreciable changes in the post natal period. Hence, they can be used as prosthesis in adults suffering from ossicular chain malformations and can be an easy and cheap method for treatment of this type of patients. 

Keywords

• ear ossicles
• incus
• malleus
• morphometry
• stapes

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