Cochlear Implantation in Superficial Siderosis with Long Term Follow-up

Le résumé fourni par la source

Superficial siderosis (SS) is a rare neurodegenerative disease resulting from toxic accumulation of hemosiderin on the surface of the brain and spinal cord because of chronic low-grade bleeding into the subarachnoid space. Its main manifestation is bilateral severe sensorineural hearing loss and there are some reports that cochlear implantation (CI) is an effective option to sustain hearing level. We report a patient with SS who underwent CI and was followed up for >8 years. A 47-year-old man with bilateral severe sensorineural hearing loss caused by SS underwent CI on the right side. Two years postoperatively, a speech discrimination test (CI2004) showed a result of 72% for words, which is indicative of a good auditory response. However, dizziness, another symptom that the patient suffered from preoperatively, gradually worsened. At 5 years after the surgery, the hearing level also declined suddenly and could not be compensated by the cochlear implant. To assess the cause of the SS and origin of the low-grade bleeding, we performed contrast-enhanced spinal magnetic resonance imaging, which revealed dural defects at the Th1 level. We removed the cochlear implant, and performed dural closure. It was difficult to close the defects completely, because they were extensive and the spinal cord was exposed with severe adhesions. The defects were covered with a polyglycolic acid sheet and fibrin glue spray, and repeat cochlear implantation was performed on the right side. However, no improvement of either the hearing level or the dizziness was observed at two years after the repeat CI. Therefore, the benefits of CI in cases of SS are variable, and the possibility of poorly sustained benefit after a good initial auditory response postoperatively should be borne in mind.

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