Biomedical subjects

Andreas Radeloff

Publications and source records attributed to Andreas Radeloff.

5 recordsLinked to original sources

PubMed2007

Impact of intrascalar blood on hearing.

OBJECTIVE/HYPOTHESIS: The objective of this controlled animal study was to evaluate the effects of intrascalar blood on hearing. MATERIAL AND METHODS: Eight guinea pigs underwent intrascalar administration of their own blood in one ear and control solution in the contralateral ear. Solutions were applied through cochleostomy to the scala tympani. Compound action potential (CAP) thresholds were determined before administration and at different intervals for 2 months thereafter. RESULTS: Immediate deterioration of thresholds was seen mainly in the high-frequency range, averaging 27 dB and 20 dB in the study and control groups, respectively. At day 3, threshold shifts recovered in the control group but remained in the low-frequency range in the study group. An extensive recovery was seen in both groups. However, permanent threshold shifts persisted. There was an enhanced shift of thresholds of up to 7 dB in the study group. CONCLUSIONS: Even small amounts of intrascalar blood seem to cause transient and permanent detrimental effects on cochlear function. In procedures involving opening of the otic capsule-like stapes surgery and cochlear implantation with hearing preservation-minimizing surgical blood admixture to intracochlear compartments seems therefore fundamental.

Animals↗

PubMed2006

Ipsilateral electric acoustic stimulation of the auditory system: results of long-term hearing preservation.

OBJECTIVE: To evaluate long-term ipsilateral hearing preservation in patients who underwent cochlear implantation for the combined electric acoustic stimulation of the auditory system. METHODS: This was a prospective observational study conducted at a tertiary referral center. Twenty-three subjects were implanted with the MED-EL C40+ standard or C40+ medium electrode using an atraumatic surgical protocol via an anterior-inferior cochleostomy approach. The desired insertion depth was 18-24 mm or 360 degrees. All patients showed significant low-frequency hearing prior to surgery and monosyllabic word scores did not exceed 40% in the best aided condition. Pure-tone audiometry was performed prior to implantation and at distinct intervals after surgery. RESULTS: Nine patients (39.1%) showed complete pure-tone audiometric hearing preservation (0-10 dB) over an average of 29 months. Seven subjects (30.4%) showed partial preservation of residual hearing (hearing loss 15-40 dB) until an average of 25 months. Delayed loss of residual hearing was observed in 5 cases (21.7%) and 2 patients (8.6%) completely lost residual hearing during or immediately after surgery. Freiburger Monosyllabic word understanding scores in a group of patients with complete hearing preservation increased from 13.1% preoperatively to 75% in the electric acoustic stimulation condition. CONCLUSION: This study documents that complete and partial preservation of ipsilateral hearing after cochlear implantation can be achieved in about 70% of cases over an average period of 27.25 months when using 360 degrees electrode insertions.

Acoustic Stimulation↗

PubMed2005

Predicting basal cochlear length for electric-acoustic stimulation.

OBJECTIVE: To assess the feasibility and accuracy of predicting electrode insertion depth necessary in cochlear implantations for electric-acoustic stimulation by means of preoperative high-resolution computed tomography (HRCT). DESIGN: Human temporal bone study with evaluation of cochlear dimensions. SETTING: Tertiary care medical center. METHODS: Eight fresh human temporal bones were scanned, and basal cochlear structures were reconstructed and measured. Standard cochlear implantations with a free-fitting array were performed, and the bones then underwent histologic analysis using a technique that allows sectioning of undecalcified bones. After embedding, all bones underwent conventional radiologic analysis with further insertion measurements. Preimplantation HRCT data were compared with radiologic and histologic data. RESULTS: Preimplantation HRCT-based measurements correlated very well with postimplantation radiologic data. A mean failure of 0.3 mm was found. Mean values for the first 360 degrees ranged from 18.8 to 22.0 mm. CONCLUSIONS: Preimplantation HRCT-based prediction of cochlear implant insertion depths is both feasible and accurate. It is especially useful when aiming for hearing preservation, where insertion depths of 360 degrees are necessary.

Adult↗

PubMed2004

Preservation of basal inner ear structures in cochlear implantation.

The aim of this report was to examine basal trauma in implanted human temporal bones and discuss modified approaches to the basal cochlear turn to avoid destruction of basal cochlear structures. Thirty-three human temporal bones were implanted with four different cochlear implant electrode arrays manufactured by MED-EL using either a caudal approach cochleostomy or round window membrane insertions. All specimens were processed with a special histological technique that allows sectioning of undecalcified bone with the electrode in situ. All bones were evaluated histologically in terms of basal cochlear trauma. Two pathomechanisms of basal trauma could be distinguished and were evaluated separately, buckling of the basal end of the array and trauma by drilling. Using the caudal approach cochleostomy, the total percentage of destructive basal trauma was 48% compared to less than 15% when performing round window membrane insertions. Although it is still unclear whether basal cochlear trauma influences apical cochlear function or not, adapted surgical procedures and no forceful insertion maneuvers should be used when performing cochlear implantations with hearing preservation.

Cochlea↗

PubMedDate not supplied

Adjuvant docetaxel, cisplatin and 5-fluorouracil (TPF) in locally advanced squamous cell carcinoma of the head and neck.

BACKGROUND: In this phase II study, the efficacy and toxicity of a triple chemotherapy with docetaxel, cisplatin and 5- Fluorouracil (TPF) was evaluated in the adjuvant therapy of locoregionally advanced cancer of the head and neck. This represented the first use of polychemotherapy as single adjuvant therapy after surgery. PATIENTS AND METHODS: Twenty patients with stage II-IV (UICC) squamous cell carcinoma of the head and neck (SCCHN) were treated by surgery of the primary and the regional lymph nodes. Four weeks after surgery, all patients received polychemotherapy consisting of docetaxel 75 mg/m2 day 1, cisplatin 100 mg/m2 day 1 and 5- Fluorouracil (5- FU) 1000 mg/m2 days 1 through 4 (total dose 4000 mg/m2), on days 1, 22 and 43 for a maximum of 3 cycles. The performance status of all patients at the beginning of the chemotherapy was 0-1 according to the Eastern Cooperative Oncology Group (ECOG). RESULTS: Fifty-eight cycles were administered to the 20 patients. The major acute toxicities were mucositis (2 patients) and febrile neutropenia (4 patients). One patient dropped out after the first cycle because of severe mucositis. After a median follow-up of 16.5 months (range, 1-41 months), the median time to progression was 20 months (range, 16-22 months). The estimated overall survival according to Kaplan-Meier at the median time of follow-up was 90%. No distant metastases were detectable after the adjuvant chemotherapy with TPF in locally advanced SCCHN, neither were late effects observed. CONCLUSION: TPF was tolerated, with an acceptable toxicity profile, in patients with a good performance status. The preliminary results appear to justify further investigations to evaluate the efficacy of this modality in the adjuvant setting.

Adult↗