Bilateral Ossiculoplasty in 1 Case of Achondroplasia
A 12 year-old female patient suffering from persistent hearing loss after birth visited the outpatient clinic for evaluation and treatment of the hearing loss. The patient showed typical features of achondroplasia, such as short limbs, especially the proximal segment, with a long trunk, narrow thorax, large head with frontal bossing, and midfacial hypoplasia at birth. Although there was no one with achondroplasia in the family, and a genetic study of FGFR3 was not performed, the typical features of achondroplasia in the patient and the short statue were enough to diagnose the achondroplasia. The patient had suffered from frequent otitis media since childhood, and had a history of bilateral tympanostomy tube insertion 7 years ago. Both tympanostomy tubes were extruded 2 years after insertion. Because she showed a feature of sensorineural hearing loss, she was referred to our hospital for consultation for hearing rehabilitation, such as the use of a hearing aid.\nThe right tympanic membrane was intact and there was a large perforation in the left tympanic membrane. Pure tone audiometry (PTA) was performed and the hearing threshold averaged from 0.5 kHz, 1 kHz, 2 kHz, and 4 kHz. The air conduction hearing threshold was 82 dB HL on the right and 52 dB HL on the right, and the bone conduction hearing threshold was 46 dB HL on the left, and 44 dB HL on the left. The type of hearing loss was mixed hearing loss (). Speech recognition threshold and the speech discrimination score were 70 dB HL and 96% on the right, and 50 dB HL and 100% on the left, respectively. On auditory brainstem response testing, there was prolonged interlatency of the right side, while the left side was normal (). The patient was recommended to use a hearing aid on the right side and have tympanoplasty for the left side. But the patient denied further treatment and was lost.\nThe patient re-visited the outpatient clinic 5 years later after the first visit. The right ear had been operated at another hospital but she still complained of hearing loss on the right side, and she suffered from intermittent otorrhea and otalgia of the left ear. There were no specific findings of the right ear. The tympanic membrane of the left ear was perforated and the margin of the perforation was attached to the mucosa of the middle ear. Air conduction and bone conduction hearing threshold were 65 dB HL and 17 dB HL for the right ear, and 30 dB HL and 12 dB HL for the left ear, respectively (). Temporal bone computed tomography was performed. The right ear was well pneumatized, and was in a canal-wall-up mastoidectomized state. There was no incus and malleus head at the epitympanum, and foreign material, estimated to be material of the implanted prosthesis, was visible in the mesotympanum. There was no abnormal lesion in the middle ear cavity. Although the left ear was well pneumatized, a lesion with soft tissue attenuation partially filled the mastoid air cells. The incus and malleus were normal in appearance ().\nRight exploratory tympanotomy was planned first because the air-bone gap was larger and the state of the tympanic membrane was better than in the left ear. A previously inserted total ossicular replacement prosthesis (TORP) was found during the operation, and the TORP was displaced from the stapes footplate. Curetting of the posterior-superior portion of the bony tympanic ring was done and a stapedial superstructure was observed. All stapedial superstructures were intact and located at the posterior-superior side of the middle ear cavity. A round window reflex during stapes palpation was observed. A partial ossicular replacement prosthesis (PORP) made of titanium was inserted on the stapes head and the conchal cartilage was interpositioned between the tympanic membrane and prosthesis head (). Gelfoam was packed into the external auditory canal, but not in the middle ear cavity. The whole of the gelfoam was removed two weeks after the operation, and postoperative PTA was performed four weeks after the operation: the hearing threshold was 22 dB HL on the right, and 38 dB HL on the left (). A second PTA was performed three months after the operation, and the hearing threshold was 21 dB HL on the right, and 36 dB HL on the left ().\nAfter confirmation of correction of hearing in the right ear, an operation on the left ear was planned. During the operation on the left ear, a large sized central perforation with adhesion of the perforation margin to the middle ear mucosa was observed. Although all ossicles were normal and their continuity was intact, the mobility of the ossicles was decreased during palpation. The incudostapedial joint was separated and the distal portion of the long process of the incus was removed because of decreased motility. The PORP was interpositioned between the stapes head and the handle of the malleus, and the conchal cartilage was also interpositioned on the prosthesis head to avoid contact of the prosthesis with the tympanic membrane. The temporalis muscle fascia was inserted via the underlay method, and gelfoam was packed into the middle ear cavity and external auditory canal. The gelfoam was removed on the postoperative 14th day. PTA was performed three months after the second operation, and the hearing threshold was 16 dB HL on the right, and 26 dB HL on the left (). The patient was observed at the outpatient clinic.