The prosthesis length in malleostapedotomy for otosclerosis revision surgery can be calculated if the prosthesis length of previous conventional incus stapedotomy is known.
Malleostapedotomy is used in revision surgery for otosclerosis in case of severe incus erosion and malleus or incus fixation.
Fifteen cadaveric human temporal bone specimens were investigated by means of micro-CT followed by 3D analysis. The distance between the incus and the stapes footplate as well as distances between the malleus and the footplate were measured and compared.
The required length of virtually bent prostheses corresponded approximately to the 1.5-fold of virtual stapes prostheses in 93%. The addition of 2 mm predicted the required prostheses length almost correctly in 80%.
The clinical practice will show whether a preoperative calculation of expected prosthesis length in MS based on the length of the formerly used stapes prosthesis is possible and helpful.