Estimation of adaptive ventilation success and failure using polysomnogram and outpatient therapy biomarkers.

Study Objectives: Adaptive servo-ventilation (ASV) devices provide anticyclic pressure support for the treatment of central and/or complex sleep apnea, including heart failure patients. Variability in responses in the clinic and negative clinical trials motivated assessment of standard and novel signal biomarkers for ASV efficacy. Methods: Multiple clinical databases were queried to assess potential signal biomarkers of ASV effectiveness, including the following: (1) attended laboratory adaptive ventilation titrations: 108, of which 66 had mainstream ETCO2 measurements; (2) AirView data in 98 participants, (3) complete data, from diagnostic polysomnogram (PSG) through review and prospective analysis of on-therapy data using SleepyHead freeware in 44 participants; and (4) hemodynamic data in the form of beat-to-beat blood pressure during ASV titration, using a Finometer in five participants. Results: Signal biomarkers of reduced ASV efficacy were noted as follows: (1) an arousal index which markedly exceeded the respiratory event index during positive pressure titration; (2) persistent pressure cycling during long-term ASV therapy, visible in online review systems or reviewing data using freeware; (3) the ASV-associated pressure cycling induced arousals, sleep fragmentation, and blood pressure surges; and (4) elevated ratios of 95th percentile to median tidal volume, minute ventilation, and respiratory rate were associated with pressure cycling. High intraclass coefficients (>0.8) for machine apnea-hypopnea index and other extractable metrics were consistent with stability of patterns over multiple nights of use. Global clinical outcomes correlated negatively with pressure cycling. Conclusions: Potential polysomnographic- and device-related signal biomarkers of ASV efficacy are described and may allow improved estimation of therapeutic effectiveness of adaptive ventilation.

Intraoperative neural response telemetry as a predictor of performance.

OBJECTIVE: To determine whether intraoperative neural response telemetry (tNRT) is predictive of postoperative speech perception. STUDY DESIGN: Retrospective review. SETTING: Tertiary referral center. PATIENTS: Children (n = 24) aged between 5 and 17 years and adults 18 years and older (n = 73) with severe-to-profound hearing loss and implanted with the Nucleus Freedom device between 2005 and 2008 and observed at least 1 year were included. INTERVENTION: Intraoperative neural response telemetry after insertion of the electrode array. MAIN OUTCOME MEASURE: Measures included 1) intraoperative tNRT measurements and 2) preoperative and 1-year postoperative open-set word recognition scores using age-appropriate open-set tests for children and adults. Intraoperative neural response telemetry levels for electrodes E20, E15, E10, and E5 in each patient were correlated to performance at the 1-year evaluation interval. RESULTS: No correlation existed between tNRT responses and open-set speech performance at the 1-year evaluation. Several patients had absent tNRT in the OR but developed speech recognition abilities, whereas the remaining patients had intraoperative responses with levels of postoperative performance ranging from 0% to 100%. CONCLUSION: This study suggests that there is no significant correlation between intraoperative tNRT and speech perception performance at 1 year. At the time of surgery, tNRT provides valuable information regarding the electrical output of the implant and the response of the auditory system to electrical stimulation and preliminary device programming data; however, it is not a valuable predictor of postoperative performance. Furthermore, the absence of tNRT does not necessarily indicate a lack of stimulation.

Processed allograft: novel use in facial nerve repair after resection of a rare racial nerve paraganglioma.

OBJECTIVES: To present a rare case of facial nerve paraganglioma and novel use of a processed allograft for facial nerve reconstruction. STUDY DESIGN: Case report and review of the literature. METHODS: A 34 year old female presented with progressive onset right sided facial palsy for 5 months. CT and MRI demonstrated an irregular mass in the right facial nerve canal from the intratympanic segment to the stylomastoid foramen. RESULTS: Following transmastoid resection, the defect was repaired using processed allograft. Pathologic analysis was consistent with a paraganglioma. Facial nerve paraganglioma is a rare entity that has been reported only 10 times in the literature. CONCLUSIONS: Traditional methods of facial nerve reconstruction, including autologous and cadaveric grafting, can lead to significant patient morbidity. Autologous nerve grafts are the "gold standard" for superior regenerative capability, but are limited by the length and potential neuroma formation at the donor site. Allogenic grafts from donors or cadavers have shown some efficacy, but can require immunosuppression. The Avance nerve graft is a cadaveric graft, processed and decellularized to maintain an extracellular matrix with laminin and intact endoneural tubes, thus providing support for the growing axon without generating an immune response. Initial studies of the Avance graft in animals and humans have examined repair of peripheral nerves, but this is the first reported case of human facial nerve reconstruction.