Impedance transfer: acoustic impedance of the annular ligament and stapedial tendon reconstruction in otosclerosis surgery.

The resistance rebuilt around the lower tip of the piston must be the same as that created by the annular ligament of the stapes footplate. Otherwise, the threshold at which an acoustic or barotrauma is able to damage the membranes and hair cells of the inner ear will be lowered. The elasticity reestablished around the lower tip of the piston plays a part in the quality and quantity of hearing for the low frequencies up to 3 kHz. To protect the ear against acoustic traumas, an attempt to rebuild the stapedial reflex is proposed.

Survival and evolution of vein grafts in otosclerosis surgery: structural and ultrastructural evidence.

The annular ligament of the stapes footplate measures 0.2 mm2 and contains elastic fibers that restrict perilymphatic movement to a molecular level. This resistance of the annular ligament prevents excessive movement of labyrinthine fluids that are potentially hazardous to the membranous and cellular structures of the inner ear. However, if the resistance of the annular ligament is overcome, then inner ear damage can occur. The vein graft, as used in our technique for otosclerosis surgery, occupies a space of 0.2 mm2 between the edge of the stapedotomy hole and the piston and has nearly the same compliance and resistance as the annular ligament of the stapes footplate. The vein graft becomes integrated with the middle-ear mucosa. It develops a rich and active blood supply and the smooth muscle cells and elastic fibers remain, although the latter show some modification of ultrastructural pattern. The graft becomes overlaid by the middle-ear epithelium. Even samples of vein graft that have been present for many years retain surviving elastic fibers, including those that have become fibrotic. In time, the number of elastic fibers increases as a result of the activity of fibroblasts, which build a poorly colored collagen.

Stapedotomy: the JB Causse technique.

The Jean-Bernard Causse technique of stapedotomy, derived from Jean René Causse "Teflon-interposition" technique, offers an optimum reconstitution of the function of the annular ligament of the stapes footplate. The quantity and quality of hearing depend significantly, among other things, on the function of the stapes footplate annular ligament. Its impedance keeps the perilymph motion within a physiological acoustic amplitude quantum level unless the movements are so excessive as in barotrauma and acoustic trauma which would have overworked even the annular ligament of a normal footplate. This surgical technique permits snorkling, scuba-diving, airplane landing, eustachian tube dysfunction after surgery as in a normal individual who did not undergo otosclerosis surgery. A comparative study on the postoperative hearing based on 3,000 out of 14,000 cases done by J C Bausse technique, 127 cases with small fenestra technique and 267 cases of complete platinectomy showed too large stapedotomy gives poor high tones and too small stapedotomy poor low tones. Five year follow-up on the hearing loss indicated that total platinoctomy has 1.7 times more alteration of 4 kHz frequency in comparison to the technique reconstituting the annular ligament. Yearly audiogram to check the evolution of cochlear otospongiosis may lead the surgeon to prescribe sodium fluoride if the mid-frequencies are deteriorating and vascular drugs if the high pitch frequencies are deteriorating.