Burkard Schwab
Research interests
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Interestsactive middle ear implant, Middle Ear, implantable hearing aid
Publications
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0.65Impact points
Controlling the position and the dislocation of the middle ear transducer with high-resolution computed tomography and digital volume tomography: implications for the transducers' design.
European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery. 09/2011;
A minimal tip dislocation of the middle ear transducer (MET(®), Otologics Ltd) may result in poor hearing performance. Our objective was to examine if a defined MET dislocation can be diagnosed by high-resolution computed tomography (HRCT) or digital volume tomography (DVT). A human cadaver head was... [more] A minimal tip dislocation of the middle ear transducer (MET(®), Otologics Ltd) may result in poor hearing performance. Our objective was to examine if a defined MET dislocation can be diagnosed by high-resolution computed tomography (HRCT) or digital volume tomography (DVT). A human cadaver head was sequentially implanted with different MET tips (incus application) including a ceramic tip (T 1c), a titanium tip (T 1t), a new, thinner titanium tip (T 2), and a spherical titanium tip (Ts). HRCT and DVT studies were performed. Afterward, the tips were pulled back 0.5 mm, so that they were not attached to the incus. HRCT and DVT scans were repeated to identify the dislocation. Using the best plain in HRCT images, the dislocation of the transducer could be measured reliably and reproducibly in half of the cases. In particular, the precise positioning and the dislocation could be identified when T 1t and Ts were implanted, with the Ts showing the best visibility. DVT failed in recognizing the dislocation in all cases. The identification of MET tip's dislocation with HRCT depends on the shape, size, and material of the tip. This knowledge is useful for the design of the implants, as determination of the right position of the middle ear transducer may be proven important for the hearing outcome. In some cases, however, surgical exploration may still be required. Although DVT represents a promising imaging method for the otologists, it can barely help when MET dislocation is suspected.
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0.50Impact points
Significance of advanced haemostasis investigation in recurrent, severe post-tonsillectomy bleeding.
The Journal of laryngology and otology. 09/2011; 125(9):952-7.
To evaluate the significance of advanced post-operative haemostasis investigation in cases of recurrent, severe post-tonsillectomy bleeding. Of the 120 patients treated at our tertiary centre between 2006 and 2010 due to post-tonsillectomy haemorrhage, 22 with recurrent, severe episodes of bleeding ... [more] To evaluate the significance of advanced post-operative haemostasis investigation in cases of recurrent, severe post-tonsillectomy bleeding. Of the 120 patients treated at our tertiary centre between 2006 and 2010 due to post-tonsillectomy haemorrhage, 22 with recurrent, severe episodes of bleeding underwent further, advanced haemostasis investigation. Underlying haemorrhagic disease was not diagnosed in any case. Isolated abnormal clotting factor levels were identified in two patients. Decreased fibrinogen concentration due to dilutional coagulopathy was found in nine cases (40.9 per cent). Recurrent, severe post-tonsillectomy haemorrhage is rarely related to undiagnosed haemostatic disorders. Thus, advanced haemostasis studies have little therapeutic relevance. However, repetitive post-tonsillectomy bleeding may be related to decreased fibrinogen levels due to dilutional coagulopathy. Therefore, fibrinogen concentration should be tested, and dilutional coagulopathy treated promptly.
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1.44Impact points
Power stapes: an alternative method for treating hearing loss in osteogenesis imperfecta?
Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. 03/2011; 32(4):589-95.
To present power stapes, stapedotomy, and middle ear implantation with Vibrant SoundBridge (VSB) performed in a one-step surgery as an alternative option for hearing rehabilitation in patients with osteogenesis imperfecta (OI). Retrospective case series. Tertiary referral ear center. A family with g... [more] To present power stapes, stapedotomy, and middle ear implantation with Vibrant SoundBridge (VSB) performed in a one-step surgery as an alternative option for hearing rehabilitation in patients with osteogenesis imperfecta (OI). Retrospective case series. Tertiary referral ear center. A family with genetically proven OI Type I. Two patients, mother and son, with severe to profound mixed hearing loss underwent 3 power stapes, 1 unilateral and 1 bilateral sequential. Thorough audiological diagnostic batteries including aided and unaided pure-tone and free-field audiometry and Freiburg monosyllabic word test were used to assess the preoperative status and the postoperative hearing outcome. High-resolution computed tomography of the temporal bones was performed as well. Surgical procedure and any special considerations were analyzed in detail. The hearing outcome was favorable in all cases, showing in comparison to the preoperative values an average improvement of 36.8 dB. Severe intraoperative bleeding of the middle ear mucosa was the only complication and could be easily controlled by allowing short time intervals. Inner ear trauma did not occur in any case. Power stapes represents a safe and promising procedure for treating hearing loss in selected patients with OI. Furthermore, it introduces a new, advantageous VSB application in cases of mixed hearing loss with severe otosclerosis and increased bone-conduction thresholds.
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0.76Impact points
Ear and further anatomic anomalies in children undergoing stapedotomy.
ORL; journal for oto-rhino-laryngology and its related specialties. 01/2011; 73(2):76-81.
Aim of this study was to examine any stapes fixation-related clinical, intraoperative and high-resolution computed tomography (HRCT) findings in children undergoing stapedotomy. Detailed diagnostic assessment was performed in 12 children (18 ears) who underwent stapedotomy within the period 2005-200... [more] Aim of this study was to examine any stapes fixation-related clinical, intraoperative and high-resolution computed tomography (HRCT) findings in children undergoing stapedotomy. Detailed diagnostic assessment was performed in 12 children (18 ears) who underwent stapedotomy within the period 2005-2008. Ear malformations such as malleus-incus anomalies, malleus-epitympanum fixation and absence of the stapedius tendon, small external auditory canal and auricle malformations were clinically and/or intraoperatively diagnosed. HRCT identified a petrous high jugular bulb and malformed inner auditory canal in 4 ears; however, it failed to recognize ossicular fixation. Systemic anomalies, namely kyphoscoliosis, esophageal atresia and finger malformations were identified in 2 children. Summing up, additional anatomic anomalies were found in 8 patients (66.7%). Ear malformations may coexist in children with stapes fixation. Ossicular fixation is not easily recognized with HRCT, and therefore, ossicular mobility should always be tested intraoperatively. In a few cases, pediatric stapes fixation can coexist with systemic dysplasias; in such patients, additional referral to geneticists is recommended.
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Bilateral otosclerosis in a child with esophageal atresia, protruding ears, hyperopia, clinodactyly, and broad thumbs: a unique clinical presentation.
Journal of otolaryngology - head & neck surgery = Le Journal d'oto-rhino-laryngologie et de chirurgie cervico-faciale. 10/2010; 39(5):E28-34.
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2.02Impact points
Anatomic limitations in implantation of middle ear transducer and carina middle ear implants.
The Laryngoscope. 08/2010; 120(11):2289-93.
The objective of this study was to examine any anatomic limitations in implantation of the semi-implantable middle ear transducer (MET) and fully implantable Carina middle ear implants (Otologics, Boulder, CO). Retrospective case series. This study involved high-resolution computed tomography (HRCT)... [more] The objective of this study was to examine any anatomic limitations in implantation of the semi-implantable middle ear transducer (MET) and fully implantable Carina middle ear implants (Otologics, Boulder, CO). Retrospective case series. This study involved high-resolution computed tomography (HRCT) of the temporal bone and surgical findings in 22 middle ear implantations (17 MET, five Carina). The distance between the dura and the superior-posterior wall of the external auditory canal (dura-meatal distance) on the incus projection level was measured in coronal high-resolution computed tomography (HRCT) sections. Extensive bone removal from the tegmen for the fitting of the implant was intraoperatively documented, using as criteria the dura exposure. The correlation between HRCT measurements and dura exposure was examined. In 10 implantations (45.5%) the dura was exposed. In nine of 10 cases (90%) the dura-meatal distance was less than 8 mm. In 11 out of 12 implantations that were performed without exposing the dura (91.7%), the dura-meatal distance was greater than 8 mm. In two cases with dura-meatal distance less than 5 mm, extensive dura exposure and surgical time were needed. In one of these cases, opening of the dura occurred during later explantation. When dura-meatal distance is greater than 8 mm, implantation of the MET or Carina is a safe procedure. By contrast, in cases with a dura-meatal distance of less than 8 mm, the surgery introduces a high risk of complications. When dura-meatal distance is less than 5 mm, MET or Carina implantation is not recommended.
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Investigation of Balance Function Using Dynamic Posturography under Electrical-Acoustic Stimulation in Cochlear Implant Recipients
International Journal of Otolaryngology. 01/2010;
Introduction. The purpose of the present study is to investigate the effect of electrical-acoustic stimulation on vestibular function in CI patients by using the EquiTest and to help answer the question of whether electrically stimulating the inner ear using a cochlear implant influences the balance... [more] Introduction. The purpose of the present study is to investigate the effect of electrical-acoustic stimulation on vestibular function in CI patients by using the EquiTest and to help answer the question of whether electrically stimulating the inner ear using a cochlear implant influences the balance system in any way. Material and Methods. A test population (n=50) was selected at random from among the cochlear implant recipients. Dynamic posturography (using the EquiTest) was performed with the device switched off an switched on. Results. In summary, it can be said that an activated cochlear implant affects the function of the vestibular system and may, to an extent, even lead to a stabilization of balance function under the static conditions of dynamic posturography, but nevertheless also to a significant destabilization. Significant improvements in vestibular function were seen mainly in equilibrium scores under conditions 4 and 5, the composite equilibrium score, and the vestibular components as revealed by sensory analysis. Conclusions. Only under the static conditions are significantly poorer scores achieved when stimulation is applied. It may be that the explanation for any symptoms of dizziness lies precisely in the fact that they occur in supposedly noncritical situations, since, when the cochlear implant makes increased demands on the balance system, induced disturbances can be centrally suppressed.
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Pressure and temperature changes in in vitro applications with the laser and their implications for middle ear surgery.
International journal of otolaryngology. 01/2010; 2010.
Background. The purpose of this study was to evaluate the thermal and pressure effects using a Titan Sapphire chirped-pulse amplifier system configured to deliver ultrashort pulses of 180 femtoseconds (fs) in an inner ear model. Materials and Methods. Temperature increases and heat exchange processe... [more] Background. The purpose of this study was to evaluate the thermal and pressure effects using a Titan Sapphire chirped-pulse amplifier system configured to deliver ultrashort pulses of 180 femtoseconds (fs) in an inner ear model. Materials and Methods. Temperature increases and heat exchange processes in the fluid (physiological saline) were examined in a calorically and physiologically approximated cochlea model for applying laser parameters effective in the creation of footplate perforations. Results. In the effective energy density range, the highest temperature increases achieved with the Carbon dioxide (CO(2)) laser were about 11 degrees C. The lowest temperature maxima were 6 degrees C with the Er:YAG laser (Yttrium-Aluminum-Oxide doted with Erbium3+-ions) and <5 degrees C with the femtosecond laser. Comparison of the laser-induced pressure with the limit graph published by Pfander indicated that the use of the fs laser is unobjectionable for fluences <1 J/cm(2). Conclusions. Our investigations demonstrated that the application of the fs laser in middle ear surgery presents a new and promising addition to the range of ultrashort wavelength lasers used for this purpose.
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1.33Impact points
Clinical feasibility test on a minimally invasive laser therapy system in microsurgery of nerves.
Minimally invasive therapy & allied technologies : MITAT : official journal of the Society for Minimally Invasive Therapy. 11/2008;
The clinical feasibility test described here evaluates the basis for a laser therapy system that enables tumour tissue to be separated from nerves in a minimally invasive manner. It was first investigated whether, using an Er:YAG laser, laser-induced nerve (specifically, facial nerve) responses in t... [more] The clinical feasibility test described here evaluates the basis for a laser therapy system that enables tumour tissue to be separated from nerves in a minimally invasive manner. It was first investigated whether, using an Er:YAG laser, laser-induced nerve (specifically, facial nerve) responses in the rabbit in vivo can be reliably detected with the hitherto standard monitoring techniques. Peripherally recordable neuromuscular signals (i.e. compound action potentials, CAPs) were used to monitor nerve function and to establish a feedback loop. The first occurrence of laser-evoked CAPs was taken as the criterion for deciding when to switch off the laser. When drawing up criteria governing the control and termination of the laser application, the priority was the maintenance of nerve function. Five needle-electrode arrays specially developed for this purpose, each with a miniature preamplifier, were then placed into the facial musculature instead of single-needle electrodes. The system was tested in vivo under realistic surgical conditions (i.e. facial-nerve surgery in the rabbit). This modified multi-channel electromyography (EMG) system enabled laser-evoked CAPs to be detected that have amplitudes 10 times smaller than those picked up by commercially available systems. This optimization, and the connection of the neuromuscular unit with the Er:YAG laser via the electrode array to create a feedback loop, were designed to make it possible to maintain online control of the laser ablation process in the vicinity of neuronal tissue, thus ensuring that tissue excision is both reliable and does not affect function. Our results open up new possibilities in minimally invasive surgery near neural structures.
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1.44Impact points
Pneumolabyrinth after cochlear implantation in large vestibular aqueduct syndrome.
Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. 11/2008; 29(7):1037-8.
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0.30Impact points
[Tuberculous Otitis media - a rare differential diagnosis in Germany]
Laryngo- rhino- otologie. 08/2008; 87(7):503-6.
A 28-year-old female patient with a migrant background presented for surgery with a suspected cholesteatoma in the left ear. The patient reported having had an aural discharge for several months; otoscopic examination revealed a runny ear, and discrete granulation tissue was seen. Pure-tone audiomet... [more] A 28-year-old female patient with a migrant background presented for surgery with a suspected cholesteatoma in the left ear. The patient reported having had an aural discharge for several months; otoscopic examination revealed a runny ear, and discrete granulation tissue was seen. Pure-tone audiometry showed conduction hearing loss of 30-40 dB across all frequencies in the left ear; high-resolution computed tomography of the temporal bone revealed that the mastoid and tympanic cavity were completely obscured. The intraoperative finding showed a caseous space-occupying mass that completely filled the tympanic cavity. The suspected diagnosis of tuberculosis was corroborated by pathohistological, microbiological and molecular biological tests. Tuberculostatic therapy was initiated at a different location. Although tuberculosis of the middle ear is a rare condition in Germany, it should nevertheless be considered when making a differential diagnosis, especially in high-risk patients where cholesteatoma is suspected on clinical and radiological evidence or in patients with a chronic middle ear process.
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0.30Impact points
[Titanium oxide ceramic as an implantation material in otosurgery: animal experimental results and surgical technique]
Laryngo- rhino- otologie. 09/2006; 85(9):635-9.
BACKGROUND: For the experimental animal study to evaluate a new ossicular chain replacement prosthesis, we developed a new technique for surgical implantation into the middle ear of rabbits. The selection of the species was based on its similarity to human middle ear anatomy and the favored, standar... [more] BACKGROUND: For the experimental animal study to evaluate a new ossicular chain replacement prosthesis, we developed a new technique for surgical implantation into the middle ear of rabbits. The selection of the species was based on its similarity to human middle ear anatomy and the favored, standardized, microsurgical approach to the middle ear cavity. METHOD: For the study we included a total of 34 approximately 6-month-old female white rabbits (New Zealand) with a weight of 3.2 to 4.4 kg. The implants used were constructed of ceramic materials TiO(2) (titania) with different pore size. Directly before the implantation of the TORPs, as well as at 28, 84 and 300 days after implantation, electric response audiometry was used to determine the hearing thresholds of the animals (bone conduction click stimulus nHL). The Erbium Yag-Laser was used to cut out the originally ossicular chain. RESULTS: After implantation we could not detect any stenosis of the outer ear canal or perforation of the tympanic membrane. The conductive hearing threshold was in the range of 4.21 +/- 6.68 dB nHL (n = 131). The hearing level showed no significant difference before and after surgery (p > 0.05). CONCLUSIONS: The laser surgery is a very safe procedure for prosthesis implantation in the middle ear of rabbits..
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1.44Impact points
Clinical results after stapedotomy: a comparison between the erbium: yttrium-aluminum-garnet laser and the conventional technique.
Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. 07/2006; 27(4):458-65.
OBJECTIVE: The objective of this study was to assess whether the use of the erbium: yttrium-aluminum-garnet (Er:YAG) laser has negative effects on inner ear function and to compare the short- and long-term hearing outcome of patients undergoing conventional stapedotomy versus laser stapedotomy. STUD... [more] OBJECTIVE: The objective of this study was to assess whether the use of the erbium: yttrium-aluminum-garnet (Er:YAG) laser has negative effects on inner ear function and to compare the short- and long-term hearing outcome of patients undergoing conventional stapedotomy versus laser stapedotomy. STUDY DESIGN: Retrospective review of prospectively collected audiometric data of patients with otosclerosis operated on by one experienced surgeon. SETTING: Academic tertiary referral center. PATIENTS: A total of 266 stapes surgeries were evaluated for intraoperative findings, of which 209 patients were evaluated for preoperative and postoperative hearing thresholds after a 6- to 452-week (mean, 22 wk) audiological follow-up. INTERVENTION: One hundred fifteen (43%) of the operations were performed conventionally, using manual perforators for stapedotomy (Group A); in 115 (43%) surgeries, the perforators were used in combination with the Er:YAG laser (Group B), and in 36 (14%) operations, the Er:YAG was used exclusively for footplate perforation (Group C). MAIN OUTCOME MEASURES: Pure-tone audiometry was performed before surgery, 2 days postoperatively (bone conduction only) and at 5, 26, and 57 weeks postoperatively. RESULTS: A postoperative temporary threshold shift of the bone conduction could be found in all groups. In Group C, where the laser was used exclusively for footplate perforation, this threshold shift was not only the most significant, but also-in contrast to the other groups-not totally reversible. In all techniques, a satisfactory air-bone gap closure could be achieved. The best long-term results (96% of the patients had <or=20 dB air-bone gap after 57 wk) could be found in Group B. CONCLUSION: If certain rules to minimize inner ear trauma are followed, the Er:YAG laser is a safe tool in middle ear surgery. Combining both the laser and the conventional technique, instead of the separate use of either technique, leads to superior postoperative hearing results.
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1.33Impact points
Four years' experience with the minimally invasive surgical approach in cochlear implant surgery.
Minimally invasive therapy & allied technologies : MITAT : official journal of the Society for Minimally Invasive Therapy. 02/2006; 15(3):187-92.
This is a prospective study on 808 profoundly or totally deaf patients who underwent either unilateral or bilateral cochlear implantation, involving a minimally invasive surgical approach, at the Medical University of Hannover's Department of Otolaryngology between May 2001 and May 2005. Advance... [more] This is a prospective study on 808 profoundly or totally deaf patients who underwent either unilateral or bilateral cochlear implantation, involving a minimally invasive surgical approach, at the Medical University of Hannover's Department of Otolaryngology between May 2001 and May 2005. Advanced Bionics, Cochlear and MED-EL devices were used, the latter having been in use at our department since the beginning of 2003.The aim of our investigation was to determine the optimal surgical technique, evaluate safety aspects and gauge patient satisfaction with this minimally invasive surgical approach during cochlear implantation. Surgical technique is analysed. Complications such as skin flap problems did not occur. The use of this minimally invasive surgical technique did not increase the surgical risk. This procedure proved both cosmetically and psychologically beneficial for patients, especially for children and their parents.
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0.98Impact points
Intraoperative computed tomography in otorhinolaryngology.
Acta oto-laryngologica. 02/2006; 126(1):82-7.
CONCLUSIONS: Intraoperative CT surgery provides the surgeon with additional information about the altered surgical site in difficult anatomical situations. The skull base and lamina papyracea may be revealed by means of intraoperative CT, which may be beneficial in endonasal sinus surgery involving ... [more] CONCLUSIONS: Intraoperative CT surgery provides the surgeon with additional information about the altered surgical site in difficult anatomical situations. The skull base and lamina papyracea may be revealed by means of intraoperative CT, which may be beneficial in endonasal sinus surgery involving difficult surgical sites, although individual ethmoid cells cannot be assessed owing to blood artefacts. This provides the surgeon with valuable information that may facilitate the procedure considerably. In soft-tissue surgery it is advisable to apply a contrast agent in order to achieve good soft-tissue contrast, thus allowing the tumour to be adequately distinguished from benign tissue. The intraoperative application of CT is a fairly time-consuming procedure, partly owing to the preparation time (set-up of the appliance; 10-min warming-up phase) and partly due to the length of time required to calculate each image (15 s). OBJECTIVE: CT is a well-established imaging method for the assessment of osseous and soft-tissue structures in the head and neck region. Saving information and transferring it to the intraoperative site may, however, be problematic. Computer-assisted navigation systems are now able to assist difficult surgical procedures in the field of otolaryngology. To investigate the indications for intraoperative CT, we used it in various surgical procedures in the head and neck region. MATERIAL AND METHODS: Intraoperative CT was applied using the Tomoscan M in 46 cases in order to demonstrate the surgical benefit of the following procedures: endonasal surgical procedures on the paranasal sinuses (maxillary and ethmoidal sinusitis, anterior fracture of the sphenoidal sinus); tumour removal by means of laser surgery (carcinomas of the hypopharynx and larynx); and cochlear implantation (to verify the electrode position). After positioning the patient on the CT table, the workstation was set up in the operating theatre. If necessary, the gantry could be moved over the patient's head without repositioning the patient. RESULTS: Intraoperative CT was used to assist in the exposure of the skull base and lamina papyracea in endonasal surgery of the paranasal sinuses. Individual ethmoidal sinuses could not be evaluated owing to blood artefacts. Intraoperative imaging proved particularly helpful in revision surgery for chronic sinusitis in cases with missing anatomical landmarks owing to previous surgeries, where there is an increased risk of inflicting damage to the skull base or orbita. The resection margins can be determined in craniofacial resections. In soft-tissue procedures, such as tumour removal by means of laser surgery, it proved possible to visualize the resection borders of malignant tumours. Assessment of the electrode position in cochlear implantation is particularly useful in revision cases and in cases of cochlear obliteration.
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0.30Impact points
[The value of dynamic posturography (Equitest) in preparing an expert's report]
Laryngo- rhino- otologie. 11/2004; 83(10):669-79.
BACKGROUND: Expert appraisals of vestibular disorders and their effects on daily life are essentially based on an evaluation of the patient's subjectively described symptoms. The aim of the present study was to ascertain the extent to which dynamic posturography is able to assist in the preparat... [more] BACKGROUND: Expert appraisals of vestibular disorders and their effects on daily life are essentially based on an evaluation of the patient's subjectively described symptoms. The aim of the present study was to ascertain the extent to which dynamic posturography is able to assist in the preparation of expert's reports. MATERIAL AND METHODS: 60 patients underwent a survey of their balance impairment. Both a nystagmus analysis, with its objective criteria, and dynamic posturography were carried out. The investigation into reduction of fitness for work (MdE) made reference to the criteria specified in the table by STOLL. The data obtained were subjected to both correlation and variance analysis. RESULTS: Although the results of this analysis revealed no direct statistical dependency, they indicated a tendency for the composite values to be correlated with the nystagmus scores and/or the MdE values (when the nystagmus score and/or the MdE increases, the composite value decreases). CONCLUSIONS: The Equitest is, according to the available data, not able to replace the currently valid MdE scores. Nevertheless, it represents a means of providing objective data about the vestibulo-spinal reflex. The test also reveals any tendencies towards simulation and aggravation. In the context of a specific nystagmus analysis, the Equitest offers an additional means of providing an objective background to back up the more subjective assessment of MdE.
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0.30Impact points
[3D-Visualisation of the middle ear by computer-assisted post-processing of helical multi-slice CT data]
Laryngo- rhino- otologie. 08/2004; 83(7):438-44.
Post-processing of CT-data allows non-invasive 3D-Visualisation of the middle ear for diagnosis and surgical planning. In this study different post-processing techniques and the clinical application of a 3D-postprocessing algorithm in a large number of patients are presented. 20 normal patients, 6 d... [more] Post-processing of CT-data allows non-invasive 3D-Visualisation of the middle ear for diagnosis and surgical planning. In this study different post-processing techniques and the clinical application of a 3D-postprocessing algorithm in a large number of patients are presented. 20 normal patients, 6 dissected temporal bones and 213 patients with suspected middle ear pathology were examined using a low-dosage Multi-Slice CT protocol. Virtual endoscopic views of the middle ear and 3D-images of the ossicles were generated using a standardised algorithm. Evaluation of the image quality was performed. The virtual views of the dissected temporal bones were compared to real views. In 32 patients high-quality 3D-models of the individual anatomical structures were generated and displayed using different visualisation techniques. The standardised and evaluated method enabled visualisation of the normal middle ear anatomy. Assessment of different pathologies, especially malformation, trauma, implants and postoperative alterations, was facilitated. The high-quality 3D-models allowed precise imaging of the anatomical structures. 3D-Visualisation of the middle ear using CT-data is beneficial for radiological diagnosis and surgical planning in cases of complex middle ear pathology as a complementary examination technique.
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0.30Impact points
[Bone ablation using ultrashort laser pulses. A new technique for middle ear surgery]
Laryngo- rhino- otologie. 05/2004; 83(4):219-25.
OBJECTIVES: Laser applications within the tympanic cavity area are widely accepted. Commonly used systems are CO(2), argon, KTP and erbium devices. The disadvantages are heat development and/or acoustic load of the inner ear. A new laser with ultra short pulses was examined concerning its ablation c... [more] OBJECTIVES: Laser applications within the tympanic cavity area are widely accepted. Commonly used systems are CO(2), argon, KTP and erbium devices. The disadvantages are heat development and/or acoustic load of the inner ear. A new laser with ultra short pulses was examined concerning its ablation characteristics and tested for possible applications in the tympanic cavity. METHODS: Investigations on human ossicles and porcine compacta were performed with a femtosecond laser in order to determine the ablation parameters. This included measurements of the dependency of the threshold energy on the pulse duration and the determination of the ablation ratio using different pulse energy levels. On the basis of histological slices the thermal damages of the bone were examined. Additionally, the processed samples were analyzed with an optical microscope and with a scanning electron microscope in order to evaluate the quality of the perforations. RESULTS: The measurements showed that the threshold energy has a lower level than the threshold energy of the conventional laser systems. At a pulse duration of 180 fs the smallest fluence, with which an erosion can be achieved, is below 1 J/cm(2). With increasing pulse duration the necessary threshold energy also rises. Due to the low energy level necessary for ablation and the extremely short pulse duration, less thermal damage is induced to the surrounding bone tissue as compared to conventional laser systems. The analysis of the scanning electron microscope demonstrates the extreme precision of this laser system. The achieved accuracy of the incisions and drillings ranges in the microm-area. CONCLUSIONS: The fs laser represents a new surgical tool for middle ear surgery. It works efficiently and in a touch-free procedure. Due to its high precision and the reduced side effects an advantage in the handling of bony structures is to be expected in relation to other laser systems. Apart from the perforation of the stapes footplate, in particular the handling and modelling of the incus, a further field of applications includes enhanced coupling, e. g. for implantable hearing aids and ossicular chain replacement prosthesis.
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0.65Impact points
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0.30Impact points
[Use of the round window micro cath for inner ear therapy - results of a placebo-controlled, prospective study on chronic tinnitus]
Laryngo- rhino- otologie. 04/2004; 83(3):164-72.
BACKGROUND: The local therapy of inner ear diseases provides a means of directly applying pharmacological substances and delivering electrical stimulation to inner ear structures. Problems relating to dosage, systemic effects and the blood-cochlear barrier are thus avoided, which is not the case wit... [more] BACKGROUND: The local therapy of inner ear diseases provides a means of directly applying pharmacological substances and delivering electrical stimulation to inner ear structures. Problems relating to dosage, systemic effects and the blood-cochlear barrier are thus avoided, which is not the case with systemic therapy. The preferred access point is the membrane of the round window. PATIENTS AND METHODS: An appropriately shaped catheter (DURECT Corporation, Cupertino, CA, USA), whose double-lumen passage system permits the variation of concentration and flow, is inserted into the round window niche. In a prospective, placebo-controlled clinical study, this application system was tested in 20 patients with chronic tinnitus. Following implantation the substances lidocaine, glutamate, glutamic acid and caroverine were applied via an attached external micropump. RESULTS: The values for tinnitus loudness, level of irritation caused by the tinnitus and subjective effectiveness of the therapy - measured by means of the visual analog scale (VAS) - showed no significant change, although the most marked improvement was indicated for caroverine. CONCLUSIONS: These results indicate that a positive effect was observable only in a proportion of the patients. Continuous therapy of tinnitus and inner ear diseases will only be possible once a totally implantable microdosage system has been developed.
Following (3)
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Jozef Hromada
Medizinische Hochschule Hannover -
Hartmut Peter Burmeister
Universitätsklinikum Schleswig - Holstein -
Gregor Theilmeier
Medizinische Hochschule Hannover
