12) Of these, compression fractures have a pattern similar to the fracture in our case. Vertebral spine fractures are classified into compression fractures, burst fractures, seat-belt type fractures, and fracture dislocations. In appearance, the fracture was like a compression wedge fracture of a vertebral body due to pressure induced vertically because the vertebral body is supported by the back muscles and tendons posteriorly. Since the posterior crus was hidden behind the posterior bony annulus and was supported by the stapedial tendon, the mechanical energy might be focused on the anterior crus, which fractured although the anterior crus is thicker than the posterior crus ( Fig. Both crura are very vulnerable because of their very thin architecture. Consequently, the air pressure acted on the ossicles, including the stapes, as a single body. The protective effect of the tensor tympani and stapedial tendon was negated by the very high air pressure and the rapidity of the explosion. We postulated that the pathophysiological mechanism of the injury was an effect of high air pressure in contact with the ear drum damaging the ossicles directly through the drum. Seventeen weeks after the revision exploratory tympano-tomy, the air-bone gap on the right side was minimal ( Fig. After repositioning the tympanomeatal flap, we confirmed the hearing improvement subjectively. Consequently, the TORP was inserted through the under-portion of the suprastructure without removing the suprastructure. Therefore, we tried removing the stapes suprastructure to insert a total ossicular replacement prosthesis (TORP), but failed because of normal footplate mobility. Moving the incus long process using an angled pick did not affect the footplate mobility. At this time, we found a fracture line through the anterior crus ( Fig. We focused stapes because other ossicles were normal condition. However, no hearing improvement was evident, and so we re-examined the ossicles. After repositioning the elevated tympanomeatal flap on the external acoustic meatus, we checked the subjective hearing gain using the whispered voice test during the operation. A mild mucosal web around the ossicles was removed. When malleus handle was manipulated, incudo-stapedial joint was moved. After tympanomeatal flaps were elevated, ossicular mobility was checked. So we planned a revision exploratory tympanotomy on the right under local anesthesia. The air-bone gap had improved on the left, while minimal change occurred on the right ( Fig. Follow-up pure tone audiometry was performed 12 weeks postoperatively.
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