Dynamic ossicular prosthesis
An ossicular replacement prosthesis includes first and second engagement structures for engaging middle ear structures, a spring that biases the first and second engagement structures longitudinally apart when under compression, and a rod that axially stabilizes longitudinal movement of the first and second engagement structures and conducts sound waves between the first and second engagement structures. Relative axial pressure on the first and second engagement structures causes compression or expansion of the spring which results in movement of the rod to adjust the length of the prosthesis to accommodate changes in anatomical distance as occurs under changes in pressure or abnormal middle ear conditions.
1. An ossicular prosthesis, comprising:
a) a first prosthesis portion having a first end for engaging a first middle ear structure;
b) a second prosthesis portion having a second end for engaging a second middle ear structure;
c) a spring that biases the first and second prosthesis portions longitudinally apart and which is expandable or compressible to self adjust a length of said prosthesis when said first and second prosthesis portions are subject to axial forces, said spring having first and second ends and defining an internal space;
d) a rod extending within the internal space of the spring and longitudinally displaceable within the internal space upon longitudinal movement of said first and second prosthesis portions relative to each other, said rod including a plurality of protuberances,
said second prosthesis portion including a resilient member defining a negative space adapted to retain a portion of said rod provided with said protuberances,
wherein said rod and said resilient member can be forced relative to each other to alter the maximum distance between said first and second ends of said first and second prosthesis portions but wherein physiological forces encountered in the middle ear are insufficient to move said rod relative to said resilient member.