Cochlear implant fixation using a subperiosteal tight pocket without either suture or bone-recess technique.

OBJECTIVES/HYPOTHESIS: To assess the complication and migration rates associated with the fixation of cochlear implant receiver-stimulators using a subperiosteal tight pocket without either suture fixation or bone recession. STUDY DESIGN: Dual-institution retrospective case review. METHODS: A retrospective case review was conducted at two tertiary referral centers. All patients who underwent cochlear implantation with device fixation using a subperiosteal tight pocket without suturing over the device or recessing of the receiver stimulator in bone were identified. There was a minimum follow-up period of 6 months. Outcome measures included intraoperative and postoperative complications, including evidence of device migration associated with interference with external device use or the need for revision surgery. Other outcome measures included soft tissue flap complications. RESULTS: Sixty-two patients were identified with a mean age of 39 years, (range 1.5-5 years). The average follow-up period was 32.6 months (range 6-120 months). Device manufacturers included Cochlear Corporation (Denver, CO) (n=44), MED-EL (Durham, NC) (n=12), and Advanced Bionics (Valencia, CA) (n=6). There were no associated intraoperative complications related to subperiosteal pocket fixation of the receiver stimulator, and no cases of migration were identified. CONCLUSION: Fixation of the cochlear implant receiver stimulator using a subperiosteal tight pocket without either suture fixation or bone recession has been demonstrated to be feasible across a range of patient demographics and cochlear implant devices. This method of fixation appears to allow for an efficient and minimally invasive approach without compromising patient safety or device performance. LEVEL OF EVIDENCE: 4.

Mannitol protects hair cells against tumor necrosis factor α-induced loss.

HYPOTHESIS: Mannitol has otoprotective effects against tumor necrosis factor (TNF) α-induced auditory hair cell (HC) loss. BACKGROUND: Mannitol has been demonstrated to possess cytoprotective effects in several organ systems. Its protective effect on postischemic hearing loss has also been shown. Mannitol's otoprotective mechanism and site of action are at present unknown. MATERIALS AND METHODS: Organ of Corti (OC) explants were dissected from 3 day-old rat pups. The safety (nonototoxicity) of mannitol was assessed at 4 different concentrations (1-100 mM). Three experimental arms were designed including: a control group, TNFα group, and TNFα + mannitol group. Cell viability was determined by counts of fluorescein isothiocyanate (FITC) phalloidin stained HC. Immunofluorescence assay of phospho-c-Jun and the proapoptotic mediators, cleaved caspase-3, apoptosis inducing factor (AIF), and endonuclease G (Endo G) were performed. RESULTS: Analysis of HC density confirmed the safety of mannitol at concentration ranges of 1 to 100 mM. The ototoxic effect of TNFα was demonstrated (p < 0.05). The otoprotective effect of 100 mM mannitol in TNFα-challenged OC explants was also demonstrated (p < 0.001). Mannitol treatment reduced the high levels of phospho-c-Jun observed in the TNFα-challenged group. AIF cluster formation and EndoG translocation into the nuclei of HCs were also reduced by mannitol treatment. CONCLUSION: Mannitol significantly reduces the ototoxic effects of TNFα against auditory HC's potentially by inhibiting c-Jun N terminal kinase (JNK) activation pathway and AIF, EndoG nuclear translocation. This local otoprotective effect may have therapeutic implications in inner ear surgery, for example, cochlear implants, protection of residual hearing, as well as implications for postischemic inner ear insults.

Management outcomes of facial nerve tumors: comparative outcomes with observation, CyberKnife, and surgical management.

OBJECTIVES: Primary facial nerve tumors (FNTs) present in varying ways. In this study, the authors present their institutional experience with the management of facial nerve tumors, including their recommendations for available therapies such as observation, microsurgical decompression or removal, and stereotactic radiation. They emphasize the auditory and facial nerve function outcomes. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. SUBJECTS AND METHODS: Retrospective review of all cases of FNT seen at the authors' tertiary care academic medical center over a 10-year period (2002-2011). The clinical presentation, treatment modality, and outcome parameters of cochlear and facial nerve function were assessed. RESULTS: Twelve patients were identified. House-Brackmann grades on presentation were 4 grade I, 2 grade II, 2 grade III, 1 grade IV, and 3 grade V, with 2 grade V patients declining to grade VI shortly after presentation. Seven patients presented with serviceable hearing and 4 with nonserviceable hearing. Treatment options/arms included observation with serial clinicoradiological review (2 cases), stereotactic radiation with the CyberKnife (3 cases), wide fallopian canal decompression (3 cases), microsurgical excision and repair (3 cases), and biopsy followed by observation (1 case). At the end of the review period, facial nerve function was stable in 8 patients, improved in 3, and declined in 1, and none had documented worsening of hearing based on American Academy of Otolaryngology--Head and Neck Surgery Foundation classification. CONCLUSIONS: Management of FNT is largely based on the clinicoradiological picture. Each treatment arm is different, but overall auditory and facial function can be maintained.