Biomedical subjects

Wolfgang Gstoettner

Publications and source records attributed to Wolfgang Gstoettner.

At least 19 recordsLinked to original sources

PubMed2007

Usefulness of MRI volumetric evaluation in patients with squamous cell cancer of the head and neck treated with neoadjuvant chemotherapy.

BACKGROUND: The purpose was to evaluate the efficacy of tumor volumetry on MRI as predictive of response to treatment with induction chemotherapy, comparing the results with endoscopy. METHODS: Fifty patients with advanced squamous cell carcinoma of the head and neck (SSCHN) who underwent MRI volumetry before and after neoadjuvant chemotherapy consisting of docetaxel, cisplatin, and 5-fluorouracil (TPF) were included in this study. The tumor volume was calculated by a slice-by-slice evaluation. With the standard software of a workstation, the area of the tumor was measured slice by slice using manual segmentation. To evaluate the efficacy of MRI volumetry, pretreatment volume was compared with pretreatment remission status as evaluated with endoscopy. RESULTS: Forty-five (90%) patients demonstrated a tumor downstaging after chemotherapy. Fourteen (28%) patients showed a complete histologic remission (CR), 31 (62%) patients showed a partial remission (PR). Pretreatment tumor volume was significantly different between patients whose tumor completely responded (CR) and those whose tumor did not completely respond or whose disease was stable or was progressive (p = .00023). We defined a threshold for the pretreatment tumor volume in patients with CR, which was equal to 29.71 cc. CONCLUSION: We propose that MRI tumor volume analyses can be a useful parameter to predict the response to neoadjuvant chemotherapy in SCCHN.

Adult↗

PubMed2006

In vivo proton MR spectroscopy of primary tumours, nodal and recurrent disease of the extracranial head and neck.

Benign and malignant neoplasms as well as metastatic lymph nodes of 39 patients were examined using localized single voxel magnetic resonance spectroscopy (MRS) [repetition time (TR) 1500, echo time (TE) 135) at 1.5 T. New techniques with simultaneous correction of motion artefacts during the acquisition, three-dimensional saturation pulses, respiratory triggering and smaller volume of interest (VOI) size, were applied. Ratios of peak areas under the choline (Cho) and creatine (Cr) resonances were estimated in all cases and compared with those from samples of normal tissue. Ninety one spectra were acquired in 39 patients, 63 of which were suitable for further evaluation. The smallest VOI was 0.40 cm(3). The Cho/Cr ratios in all malignant neoplasms (mean: 5.2, range: 1.7-17.8) were significantly elevated relative to those in the normal muscle structures (mean: 0.9, range: 0.2-1.4), while those in the benign neoplasms were elevated (mean: 24.4, range: 1.4-59.7) with respect to those in the malignant ones. The average Cho/Cr ratio in the metastatic lymph nodes was significantly higher (mean: 4.8, range: 3.3-5.6) than that for benign lymphoid hyperplasia (mean: 2.2, range: 1.0-3.0). MRS measurements were able to differentiate recurrent disease from post-therapeutic tissue changes in 11 out of 13 patients.

Adult↗

PubMed2006

AdOnco: a database for clinical and scientific documentation of head and neck oncology.

OBJECTIVES: The aim of this project was to design, develop, and implement a head and neck cancer computer database for clinical and scientific use. METHODS: A relational database based on Filemaker Pro 6.0 was developed and integrated into our local network. A precise and easy-to-handle interface should allow for a quick overview of the patient's oncological history and for optimized data acquisition. An automatic report function was integrated to enhance the quality of daily patient care. For evaluation purposes, statistical analysis functions were implemented. RESULTS: Over a 14-month period, 410 patient records were available through the local network. The automated report function and the well-organized screen desktop resulted in time-efficient and accurate patient care. Additionally, the quality of information presented to referring physicians increased notably. The statistical analysis data provided by the database were reliable and easy to export. CONCLUSIONS: We developed an oncology database for both clinical and scientific purposes and integrated it successfully into our patient documentation system. The combination of clinical and scientific features proved to be very effective in daily routine and research.

Algorithms↗

PubMed2005

Combined electric and acoustic stimulation of the auditory system: results of a clinical study.

Combined electric and acoustic stimulation (EAS) of the auditory system is a new therapy for patients with severe to profound high- and mid-frequency hearing loss but remaining low-frequency hearing. In a prospective study, 13 patients with low-frequency hearing of better than 60 dB below 1 kHz were implanted with a MED-EL COMBI 40+ cochlear implant. Pure tone thresholds as well as monosyllabic word scores and Hochmair-Schulz-Moser sentences in quiet and in noise were measured with hearing aids, cochlear implant alone and in the combined stimulation mode (EAS) in the same ear. Hearing could be partially preserved in 11 out of the 13 patients. All patients scored significantly higher with cochlear implant alone than with hearing aids. Seven patients scored higher in the EAS mode than with cochlear implant alone for sentences in noise, 4 remained unchanged, and 2 could not use EAS. Synergistic effects of EAS were most prominent for hearing in noise with increases of up to 72% as compared to cochlear implant alone.

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↗

PubMed2005

Does the 23-valent pneumococcal vaccine protect cochlear implant recipients?

OBJECTIVES/HYPOTHESIS: The incidence of meningitis is increased in cochlear implant (CI) recipients. Besides malformations, immunological deficiencies are predisposing factors. Therefore, the immunological background of CI recipients and the immunogenicity of the recommended 23-valent pneumococcal polysaccharide vaccine (PPV-23) were investigated. STUDY DESIGN: Prospective study in a tertiary care referral center. METHODS: One hundred twenty CI recipients who were at least 5 years of age were vaccinated with PPV-23. Levels of immunoglobulins G, A, and M (IgG, IgA, and IgM, respectively) and IgG subclasses IgG1-IgG4 before vaccination and serum concentrations of antibodies against seven pneumococcal serotypes before and 4 weeks after vaccination were determined. The cohort was subdivided by patient age into groups A1 (5-8 y), A2 (8-12 y), and A3 (>12 y). RESULTS: Geometric mean concentrations of pneumococcal antibodies before vaccination were remarkably low in all three groups, emphasizing the importance of vaccination in this risk group. All groups showed a statistically significant increase in geometric mean concentrations after immunization. For group A1 compared with groups A2 and A3, response was limited, especially for serotypes 6B (geometric mean concentration, 1.71 microg/mL; P = .0007), 23F (geometric mean concentration, 2.28 microg/mL; P = .04), and 14 (geometric mean concentration, 3.98 microg/mL; P = .0004). The percentages of patients reaching the presumed protective threshold of at least 1 microg/mL pneumococcal antibody concentration were at least 71.1% in group A1, 93.8% in group A2, and 90.5% in group A3. This raises the question of whether PPV-23 evokes satisfying seroprotection in CI recipients younger than 8 years of age. CONCLUSION: With regard to the increased risk for bacterial meningitis, the authors recommend priming CI recipients younger than 8 years of age with pneumococcal conjugate vaccine followed by a PPV-23 booster.

Adolescent↗

PubMed2005

Surgical considerations in cochlear implantation in children and adults: a review of 342 cases in Vienna.

CONCLUSIONS: Our data represent the experience of the largest cochlear implant program in Austria. In conclusion, cochlear implantation is a safe procedure, associated with a low rate of intra- and postoperative complications. Nevertheless, patients should be informed about possible problems and especially about the risk of a reoperation due to device failure. OBJECTIVES: To evaluate the cause of deafness, the intraoperative findings and the complication rate for all cochlear implant operations performed consecutively between 1994 and 2003 at Vienna General Hospital. MATERIAL AND METHODS: Including all surgeries for bilateral implantation and revision, a series of 342 operations performed on 164 adults (age range 14.5-81 years; mean age 50.79 years) and 128 children (age range 0.75-14 years; mean age 5.00 years) was retrospectively analyzed. RESULTS: The etiology of deafness was predominantly congenital or progressive (66.89%). The routine mastoidectomy approach was chosen in 300 patients (87.72%) and the suprameatal approach in 42 (12.28%). Intraoperatively, 4 children (2.53%) had a cerebrospinal fluid fistula and 35 patients (10.23%) showed cochlear ossification. Three adults (1.63%) and two children (1.27%) had facial nerves with an aberrant course. The overall complication rate was 12.2%, the rate of major complications was 4.97% and the rate of minor complications was 4.09%. There were no cases of either postoperative meningitis or facial nerve palsy. Both flap necrosis and electrode dislocation occurred in one adult patient (0.54%), but in none of the children. Formation of cholesteatoma was found in one adult (0.54%) and one child (0.63%). The rate of device failure was 7.07% for adults and 13.92% for children.

Adolescent↗

PubMed2004

Audiological performance after cochlear implantation in children with inner ear malformations.

OBJECTIVES: To prove that cochlear implantation is a beneficial method of rehabilitation in deaf children with malformations of the inner ear. DESIGN: The evaluation of auditory responses to speech (EARS) test battery was performed on the children in this study after an average implant use of 3 years. RESULTS: Individual results of six children with inner ear anomalies receiving cochlear implants are presented in this study. Three of the patients showed an incomplete partition (Mondini dysplasia), one had a cochlear hypoplasia and two suffered from an intraoperative cerebrospinal fluid leak. The majority of the children in this study are successful implant users. Wherever possible, test scores are included and subjective case reports given. CONCLUSIONS: Results are similar to those in children with normal cochleas, therefore inner ear malformations found in as many as 20% of patients with congenital sensorineural hearing loss are no contraindication for cochlear implantation. Nevertheless, factors influencing the success of implantation are multiple, including a thorough preoperative radiological examination, a well-performed surgery and an individually tailored postoperative rehabilitation programme.

Audiometry, Speech↗

PubMed2004

Conservation of low-frequency hearing in cochlear implantation.

OBJECTIVES: As results with cochlear implants have continued to improve, patients with some remaining cochlear function have become eligible for cochlear implantation. Thus, preservation of acoustic hearing after implantation has gained importance. Hearing preservation can be considered a benchmark for atraumatic implantation preventing neural degeneration from loss of residual hair cells or subsequent to local trauma. In this prospective study, the possibility of preserving low-frequency hearing in cochlear implantation using a modified surgical technique has been explored. MATERIAL AND METHODS: In a prospective study design, 14 subjects with considerable low-frequency hearing of 20-60 dB in the frequency range 125-500 Hz but with unsatisfactory speech understanding with hearing aids of < 35% monosyllabic word understanding were implanted with a MED-EL COMBI-40+ cochlear implant. The insertion depth was intentionally limited to 19-24 mm to prevent damage to low-frequency regions of the cochlea. Pre- and postoperative pure-tone thresholds were measured. RESULTS: Hearing was conserved within 0-10 dB in 9/14 subjects and within 11-20 dB in 3/14; in 2/14 subjects hearing was completely lost in the implanted ear. Thus hearing could at least partially be conserved in 12/14 subjects (86%). Median threshold values decreased by 10, 15, 17.5 and 5 dB at 125, 250, 500 and 1000 Hz, respectively. Even high levels of hearing, e.g. 30 dB at 500 Hz, could be maintained after implantation in some subjects. CONCLUSIONS: This study reports successful conservation of hearing after cochlear implantation using a modified surgical technique. Even high levels of hearing could be maintained, showing that implantation of an intracochlear electrode can be performed atraumatically with preservation of functional structures.

Adult↗

PubMed2004

Hearing preservation in cochlear implantation for electric acoustic stimulation.

OBJECTIVE: To evaluate the possibility of preservation of low-frequency hearing in atraumatic cochlear implant electrode insertion procedures for combined, ipsilateral electric and acoustic stimulation. MATERIAL AND METHODS: A total of 21 patients were implanted with a MED EL C40+ cochlear implant using an atraumatic electrode insertion technique to preserve residual low-frequency hearing. Pure-tone audiometric thresholds were measured pre- and postoperatively to evaluate the degree of preserved hearing. Speech discrimination tests in quiet and with background noise were performed in a patient with successful hearing preservation. RESULTS: Using the atraumatic electrode insertion procedure with an insertion depth of 360 degrees (18-24 mm), hearing preservation could be achieved in 18/21 patients (85.7%). Three patients (14.3%) lost their residual low-frequency hearing after the implantation. Residual hearing was preserved completely in 13 patients (61.9%) and partial hearing preservation was possible in 5 (23.8%). Preliminary speech discrimination tests showed a dramatic benefit for the combined electric and acoustic stimulation mode compared to cochlear implantation alone. CONCLUSION: Preservation of low-frequency hearing in cochlear implantation is possible in patients implanted because of profound high-frequency deafness. With the development of new, more atraumatic electrode designs, preservation of residual hearing should be further improved.

Acoustic Stimulation↗

PubMed2004

Cochlear implantation via the round window membrane minimizes trauma to cochlear structures: a histologically controlled insertion study.

OBJECTIVE: To evaluate cochlear implant trauma to intracochlear structures when inserting the electrode via the round window membrane. MATERIAL AND METHODS: Eight fresh human temporal bones were evaluated histologically after insertion using two types of cochlear implant array. Bones underwent a special fixation and embedding procedure that allowed sectioning of undecalcified bone with the electrode in situ. Insertions depths were evaluated radiologically and histologically. RESULTS: All arrays were found in the scala tympani of the cochlea. Basal trauma could be avoided in all but one specimen. The mean depth of insertion was 382.5 degrees. Apically, only one implanted bone showed cochlear trauma exceeding lifting of the basilar membrane. CONCLUSION: Insertions through the round window membrane were shown to be atraumatic, even in basal cochlear regions. This route of insertion might be very effective for combined electric and acoustic stimulation of the auditory system.

Cochlea↗

PubMed2004

Development and evaluation of an improved cochlear implant electrode design for electric acoustic stimulation.

OBJECTIVE: The objective of this study was to assess the intracochlear position and the extent of trauma to cochlear structures using a new prototype electrode carrier (Flex EAS). Special emphasis was placed on the practicality for combined electric and acoustic stimulation of the auditory system. STUDY DESIGN: Human temporal bones were evaluated histologically after insertion of the electrodes, and insertion forces were measured in an acrylic model of the scala tympani. METHODS: 1) Insertion forces with the regular C40+ array and the new electrode prototype were measured in an acrylic model of the scala tympani. 2) Ten human temporal bones were implanted using the same surgical procedure as in vivo. All bones underwent fixation methylmethacrylate embedding to allow cutting of the undecalcified bone with the electrode in situ. In addition, radiography of the implanted devices was performed and correlated to histologic results. Electrode positions and trauma to cochlear structures were then evaluated histologically. RESULTS: All insertions of the new electrode array were performed in the scala tympani of the cochlea. All insertions were atraumatic and covered one cochlear turn. The only effect on cochlear structures that could be observed was a slight lifting of the basilar membrane in the middle turn limited to the tip of the electrode. In three bones, basal trauma, which resulted from the cochleostomy itself, could be observed as well. All neural structures remained intact. CONCLUSIONS: The new electrode prototype provides very good mechanical properties for safe and atraumatic implantation. All criteria for the use in hearing-preservation cochlear implantation for electric and acoustic stimulation were fulfilled. Surgical measures to prevent basal trauma appear to be very important.

Acoustic Stimulation↗

PubMed2004

Application of carbon dioxide and erbium:yttrium-aluminum-garnet lasers in inner ear surgery: an experimental study.

BACKGROUND: Surgery of the inner ear requires atraumatic techniques to preserve the sensory structures of the inner ear. With modern laser technology, surgery can be performed without mechanical contact, reducing the risk of direct mechanical trauma. However, energy transfer by laser light has the potential to induce damage by heating, pressure waves, or direct irradiation, depending on the properties of the laser and parameters of application. HYPOTHESIS: The application of laser systems in inner ear surgery may have an advantage over traditional techniques; the carbon dioxide laser in continuous mode with an automated scanning procedure and the erbium:yttrium-aluminum-garnet laser were compared with a mechanical technique, using a diamond drill. METHODS: A cochleostomy in the basal cochlear turn of guinea pigs was created. Thresholds in response to frequency-specific stimuli and clicks were established by recording compound action potentials, both before and after the procedure. RESULTS: The best results in terms of preservation of cochlear function were obtained with the diamond drill. However, a single ear had a complete loss after fracture of the cochlear wall. Mean threshold shifts observed with the carbon dioxide laser were slightly greater, showing mild high-frequency losses, although differences to the group of drilling were not statistically significant. Results with the erbium:yttrium-aluminum-garnet laser showed significantly higher degrees of hearing loss than the other two groups, predominantly in the high-frequency region. CONCLUSIONS: Mechanical opening of the inner ear using a microdrill can be performed with minimal hearing loss; however, it carries the risk of direct trauma to the inner ear. The carbon dioxide laser with a new scanning technology as a noncontact procedure is shown to be effective and safe. It can be regarded as a useful tool in inner ear surgery. The erbium:yttrium-aluminum-garnet laser has a greater potential to cause damage.

Aluminum↗

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↗

PubMed2004

Speech perception with a cochlear implant used in conjunction with a hearing aid in the opposite ear.

The aim of this study was to determine the improvement in speech recognition provided by a cochlear implant (CI) in conjunction with a hearing aid (HA) in the opposite ear. The study was a retrospective cohort study in the context of a university teaching hospital CI programme. Seven CI patients who still use their HA in the opposite ear were tested. The scores with the CI alone and the CI in conjunction with an HA were evaluated by using three speech perception tests in quiet (Freiburger Numbers. Freiburger Monosyllables, and Innsbrucker Sentence Test). In the majority of tests and subjects. the CI alone performed better than the HA alone, and the bimodal (CI + HA) condition was superior to the CI alone. On the sentence test, the patients as a group improved from 47 96% (mean: 79%; CI alone) to 50-100% (mean: 88.1%; CI + HA, pv < 0.05). With the more difficult monosyllable test, the scores improved from 15-52% (mean: 37.2%; CI alone) to 15 82% (mean: 48.7%; CI + HA, p < 0.05). On the numbers test. scores increased from 65-98% (mean: 83%; CI alone) to 75-98% (mean: 88.7%; CI + HA, p < 0.05). All patients in this study were implanted in the poorer ear. The results of the present study suggest the advantage of CI usage in conjunction with an HA in the opposite ear.

Acoustic Stimulation↗

PubMed2003

Variables affecting speech perception in postlingually deaf adults following cochlear implantation.

OBJECTIVE: To evaluate the time span over which there is greatest improvement in postlingually deaf adults undergoing cochlear implantation. Additionally, to quantify potential patient and device factors that may predict the postoperative results. MATERIAL AND METHODS: A longitudinal study was conducted. Numbers, monosyllables and sentence test results were collected for 66 cochlear implant subjects [Combi 40/40 +, n = 60; Clarion HF2, n = 2; Nucleus 24m/k, n = 4] at regular intervals for up to 6 years following cochlear implantation. RESULTS: All patients showed a steady improvement over time on all tests. Progress during the first 12 months was statistically significant, with further improvements being recorded after the 12-month testing period. The duration of deafness and the number of electrodes (8 for the Combi 40, 12 for the Combi 40 + ) appeared to be weakly correlated with postoperative performance. Re-implantation after device failure had no negative effect on speech reception. Subjects who were "upgraded" from an analogue to a digital cochlear implant improved their test results almost twofold. CONCLUSION: All the patients in our study gained substantial benefit from their cochlear implants. It is encouraging to note that the factors examined were not deemed to be relevant predictors of performance. Even long-term deaf subjects and re-implantees are able to achieve an excellent level of speech perception.

Cochlear Implantation↗

PubMed2003

Expression of hypoxia inducible factor 1 alpha and Von Hippel Lindau protein in human middle ear cholesteatoma.

OBJECTIVE: To evaluate the role of hypoxia in cholesteatoma progression. STUDY DESIGN: Immunohistochemical analysis of paraffin-embedded human specimens. METHODS: Thirteen middle ear cholesteatomas and 10 samples of normal human external ear canal skin were stained immunohistochemically for the presence of hypoxia inducible factor 1 alpha (HIF 1 alpha) and Von Hippel Lindau protein. Specimens were then analyzed semiquantitatively. RESULTS: Staining for both antibodies could be detected in all cholesteatomas (perimatrix and matrix), as well as in the samples of normal human ear canal skin. Cholesteatoma specimens showed statistically significant increased staining when compared with normal human skin and mucosa. The age of patients and relapse surgery affected immunohistochemical staining of HIF 1 alpha and Von Hippel Lindau protein. CONCLUSIONS: Elevated staining intensities for HIF 1 alpha and Von Hippel Lindau protein in cholesteatoma tissue indicated that cholesteatoma may be hypoxic. In addition, our data indicated that relapse cholesteatomas yield a higher degree of hypoxia than ears without surgery.

Adolescent↗

PubMed2002

The role of age in pediatric cochlear implantation.

OBJECTIVE: To document progress, benefit and importance of age in paediatric cochlear implantation. DESIGN: The EARS (Evaluation of Auditory Responses to Speech) test battery was performed on 33 prelingually deaf children at regular intervals up to 36 months following implantation. All children participated in individually tailored intensive audiological rehabilitation programs after receiving their implants. In this respect, it was attempted to evaluate speech perception scores in children implanted before and after the age of 3 in a homogenous group. RESULTS: All children demonstrated encouraging improvements over time in their speech recognition abilities. Furthermore, it was observed that the children who were implanted under the age of 3 achieved higher levels of speech perception performance. CONCLUSION: In order to shorten the process of central maturation of the auditory system, it is desirable to implant the children as young as possible. Early intervention seems to be the ideal strategy in enabling prelingually deaf children to derive maximum benefit from cochlear implantation.

Age Factors↗