Is the Prosthesis Length in Malleostapedotomy for Otosclerosis Revision Surgery Predictable?

HYPOTHESIS: The prosthesis length in malleostapedotomy for otosclerosis revision surgery can be calculated if the prosthesis length of previous conventional incus stapedotomy is known. BACKGROUND: Malleostapedotomy is used in revision surgery for otosclerosis in case of severe incus erosion and malleus or incus fixation. METHODS: 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. RESULTS: 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%. CONCLUSION: 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.