Abstract
Intralabyrinthine schwannomas are rare tumors of the distal ends of the cochlear and vestibular nerve. Their presence can be debilitating secondary to symptoms of hearing loss, vertigo, tinnitus, and imbalance. Currently, treatment to restore hearing in those who have become profoundly deaf is not attempted. Additionally, resection in patients with functioning hearing is rare, as the surgery assures deafness. We report the first case demonstrating the feasibility of resection of an intralabyrinthine schwannoma with immediate cochlear implantation. This technique addresses the patients hearing status by taking into account advancing technology, allowing for an improved quality of life.
1
Introduction
Intralabyrinthine schwannomas are a type of rare tumor that represents a distinct clinical entity, separate from vestibular schwannomas . Common complaints include hearing loss, vertigo, tinnitus, imbalance and aural fullness . Because symptoms mimic many neurotologic pathologies, especially Meniere’s disease, there is often a delay to diagnosis. Fluctuating hearing is found in only 3% of tumors helping in differentiation . The diagnosis of an intralabyrinthine schwannoma is made by MRI, showing enhancement in T1 post-gadolinium images . T2 images may further delineate the extent of the mass through loss of fluid signal, caused by the presence of tumor . Surgical removal has previously been reserved for patients with debilitating vertigo in a non-hearing ear, in those rare cases of tumor growth and when concern about pathologic diagnosis exists, since the invasive nature of the surgery assures deafness . These treatments have not taken into account advancing technologies such as cochlear implants. Our case demonstrates the value of surgical treatment in effort to decrease vertigo and tinnitus while restoring hearing though the resection of tumor with immediate cochlear implantation.
2
Case report
A 65-year-old male was seen in consultation for severe vertigo with imbalance associated with moderate to severe left fluctuating hearing loss and aural fullness for 3 months. The patient experienced progressive right profound hearing loss over the prior 12 years. Tinnitus occurred in both ears but was more prominent on the right side. Vestibular-evoked myopotentials were absent bilaterally indicating a peripheral pathology, but caloric examination was normal. A diagnosis of bilateral Meniere’s disease was made and treatment with a low-salt diet and hydrochlorothiazide/triamterene was initiated. Medical treatment provided some relief of vertigo, but over 4 years, his left hearing loss progressed with continued imbalance and vertigo and a cochlear implant evaluation for his right profound loss was done. After passing implant criteria, MRI with gadolinium was obtained for surgical planning. T1 post-contrast images showed the presence of an enhancing mass in the right cochlea extending to the apical turn with additional involvement of the vestibule, saccule, and the superior and posterior semi-circular canals, consistent with an intravestibulocochlear schwannoma ( Fig. 1 ). After the discussion with the patient resection of the schwannoma with immediate cochlear implantation was planned.
Through a facial recess approach the basal turn of the cochlea was opened from the round window for 4–5 mm. The schwannoma filled the basal turn of the cochlea with apical extension and extension into the vestibule. The tumor was removed with meticulous microdissection and a Nucleus Freedom device (Cochlear: Macquarie Park, Australia) was inserted. Temporalis fascia was placed around the electrode along the exposed basal turn region.
Postoperatively the patient had decreased complaints of tinnitus and vertigo, with excellent hearing results ( Table 1 ; Fig. 2 ). The patient was able to use all electrodes of the cochlear implant without facial stimulation or pain.
| Hearing results | Pre-treatment PTA | Pre-treatment WRS | Post-treatment PTA | Post-treatment WRS |
|---|---|---|---|---|
| Right ear | 110 db | DNT | 25 db | 84% |
| Left ear | 50 db | 64% | 40 db | 56% |
Yale IBR approval was obtained before the start of the investigation.
2
Case report
A 65-year-old male was seen in consultation for severe vertigo with imbalance associated with moderate to severe left fluctuating hearing loss and aural fullness for 3 months. The patient experienced progressive right profound hearing loss over the prior 12 years. Tinnitus occurred in both ears but was more prominent on the right side. Vestibular-evoked myopotentials were absent bilaterally indicating a peripheral pathology, but caloric examination was normal. A diagnosis of bilateral Meniere’s disease was made and treatment with a low-salt diet and hydrochlorothiazide/triamterene was initiated. Medical treatment provided some relief of vertigo, but over 4 years, his left hearing loss progressed with continued imbalance and vertigo and a cochlear implant evaluation for his right profound loss was done. After passing implant criteria, MRI with gadolinium was obtained for surgical planning. T1 post-contrast images showed the presence of an enhancing mass in the right cochlea extending to the apical turn with additional involvement of the vestibule, saccule, and the superior and posterior semi-circular canals, consistent with an intravestibulocochlear schwannoma ( Fig. 1 ). After the discussion with the patient resection of the schwannoma with immediate cochlear implantation was planned.
