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After approximately 100 years of development and stepwise improvement, stapes surgery is a succesful strategy of managing hearing loss in otosclerosis, although challanges remain. Contraindications include too poor speech understanding (not enough inner ear reserve), and acute or chronic inflammation of the external ear and middle ear. Stapes surgery in the last hearing ear can today be indicated in exceptional cases, especially if the contralateral ear was supplied with a cochlear implant. In case of simultaneous occurrence of pronounced external auditory canal exostoses, a staged procedure may be useful.The surgical principle is to mechanically replace the fixed stapes with a piston-shaped implant under perforation or partial removal of the stapes footplate. Laser-assisted stapes surgery has proven itself in practice and the laser is used regularly today. In regard to revision surgery the increased risk of hearing loss or deafness and vertigo has to be considered. Revisions are made in the event of complications and persistent or newly occurring conductive components. In the case of insufficient hearing rehabilitation, alternative options should be considered, e. g. the combination of a stapes plastic with an active middle ear implant, or a cochlear implant., Competing Interests: Wir danken der Firma ARRIMEDICAL, München, Deutschland, für die Unterstützung bei der Erstellung der Videos (Schnitt, „post production“) zur Demonstration der Stapesoperation.Angaben für Prof. Plontke: Otonomy Inc., San Diego, USA (Consultant); AudioCure Pharma GmbH, Berlin, Deutschland (Scientific Advisory Board); MedEl, Österreich und MedEl, Deutschland (Forschungsprojekte, Reisekosten); Merck Serono, Darmstadt, Deutschland (Vortragshonorar); Hoffmann-La Roche, Basel, Schweiz (Consultant); Cochlear Ltd., Australien (Forschungsprojekte, Reisekosten); Infectopharm, Germany (Vortragshonorar); Boehringer Ingelheim, Deutschland (Consultant); Sensorion, Frankreich (Consultant)Prof. Zahnert: Firmen: MED-EL Innsbruck/Österreich ; Heinz KURZ GmbH Medizintechnik- Dusslingen/Deutschland; Cochlear Deutschland GmbH & Co. KG: Forschungskooperation; Reiseunterstützung; Vortragstätigkeit, (Georg Thieme Verlag KG Stuttgart · New York.)

Hospital facilities issue numerous risk announcements on corrosion, deformation or premature wearout of medical devices every year. As there is yet little data on the impact of reprocessing on the quality and durability of microsurgical instruments, this paper aims at evaluating the effects of the reprocessing on microsurgical instruments. Material and Methods 22 brand new microsurgical instruments for stapes surgery were being reprocessed 30 times without being used for surgery or other purposes in the interim time. After each reprocessing the instruments were examined macroscopicly and microscopicly. The results were portrayed in a photo documentation and analysed on that basis. Results Almost all devices showed mechanical damage caused by the reprocessing procedure. The increasing deterioration was often associated with missing protective caps. Furthermore contaminations and stains were apparent in several cases. Conclusions The findings illustrate that careful handling of delicate surgical devices during reprocessing is vital. They also highlight problems of protective caps. As an alternative going forward it should be considered to store microsurgical instruments statically in special racks., Competing Interests: Interessenkonflikt: Die Autoren geben an, dass kein Interessenkonflikt besteht., (Georg Thieme Verlag KG Stuttgart · New York.)

Background: Microsurgical preparation is limited by geometric and mechanical constraints. In preparation for clinical use, this study investigates performance, ease of handling and precision of a novel manipulator concept for microsurgery., Material and Methods: A group of 15 ENT experienced doctors, as well as a group of 17 medical students with low/non surgical experience participated in the study. Each of the subjects carried out 4 trials of simulated surgeries on a phantom with built-in force sensors. The task was to apply a defined force between 1.5 and 2 N using a Fisch micro perforator, 16 cm length, 0.4 mm (Storz) targeting holes with a diameter of 0.5 mm. For comparison, the Fisch micro perforator was moved manually or with the manipulator., Results: Assessing the total number of errors proved a significantly lower error number (p<0.0001) and an improvement of the accuracy of 76% with the manipulator. The time requirement for the procedure with the micro manipulator is on average 2-3 times higher than with manual control (p<0.0001). But it is notable that this time requirement significantly decreases with training (p<0.0001)., Conclusion: The study shows a significant reduction in the number of errors by using a new manipulator concept compared to the non-augmented human hand in an experimental setup. We observed a significant learning effect when subjects applied the micro manipulator, resulting in reduction of the time requirement while maintaining a constant number of errors., (© Georg Thieme Verlag KG Stuttgart · New York.)

Background: CT and MRI of the windows of the temporal bone have become an important tool in the analysis of malformation, trauma and chronic otitis media. Optical Coherence-Tomography (OCT) provides optical cross-sections of the tissue, comparable to ultrasound. In a study on temporal bone specimens and during middle ear surgery we tested, whether OCT provides information about the oval window niche., Material and Methods: OCT was performed ex vivo on five human temporal bone preparations, in which the oval window niche was exposed and in vivo in eight patients who underwent middle ear surgery. A new OCT device, which based on spectrally resolved detection of the interference signals, was used. This OCT technology was fully integrated into an operating microscope. For direct correlation between OCT-scans and histology, three temporal bones were used., Results: On all ex and in-vivo scans OCT supplies information about morphology of the stapes footplate. This OCT investigation documents the possibility to visualize in vivo annular ligament, different layers of the FP and inner ear structures., Conclusions: Intra-operative OCT application will help to visualize FP anomalies. Our study provides morphological information of the FP that may help in stapes surgery of the patients concerned.

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.

Background: The analysis of postoperative results after Erbium : YAG-Laser stapedotomy in patients with otosclerosis., Methods: For all operations the microscope-integrated Erbium : YAG-Laser Twin ER (Zeiss, Oberkochen) was used by different surgeons. Data of 53 patients who were operated on between October 1993 and May 1999 were analysed. The mean follow-up time was 17 months. Postoperative bone-conduction and air-conduction thresholds and the presence of postoperative tinnitus and vertigo were analysed. The data were analysed according to the guidelines of the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery (1994)., Results: In 49 patients unchanged preoperative minus postoperative pure tone bone conduction averages at 1, 2, and 4 kHz were observed. In 4 patients a slight deterioration between 10 and 20 dB was seen. In 2 patients a new postoperative tinnitus was observed. No patient suffered from vertigo at the time of evaluation. In 22 patients the postoperative air-bone gap was between 0 and 10 dB, in 25 patients between 11 and 20 dB, and in 6 patients between 21 and 30 dB. No patient had a postoperative air-bone gap of more than 30 dB., Conclusions: The Erbium : YAG-Laser stapedotomy is a safe technique. Good postoperative hearing results may be achieved in patients with otosclerosis.

Background: Middle ear surgery has reached an advanced stage of development over the last few decades. The use of biocompatible materials offers new possibilities in ossiculoplasty. The exact calculation concerning the length of the implant to be used, however, still poses considerable difficulties and is an additional cause for a remaining air conduction difference or a further surgical intervention., Methods: Optical coherence tomography (OCT) is a non-invasive imaging procedure for the imaging of tissue structures with a resolution accurate to micrometres. OCT can be operated touch-free and for this reason does not require any means of contact between applicator and sample. In the present study an optical coherence inferometre was coupled to an operating microscope and used in 5 stapedoplasties and 5 tympanoplasties type III in order to determine the length of the prosthesis to be used., Results: The use of OCT implies an intraoperative measuring time of only a few seconds. The coupling in the optical path of an operating microscope allows trouble-free handling. The measurement of middle ear structures has an accuracy of 30 micrometer. The postoperative audiological results show a good auditory performance., Conclusions: Initial experience with OCT indicates that the technology will be extremely interesting for otosurgery. Improvements in functional pattern will enable routine intervention in connection with an operating microscope. Further OCT applications for tissue differentiation will have to follow.

Background: Recent experimental studies have demonstrated that, apart from the continuous wave lasers, several pulsed laser systems are also suitable for stapedotomy. The aim of this study was to clarify whether irradiation of the basal convolution of the guinea pig cochlea could cause morphological inner-ear changes using the Er:YSGG and Ho:YAG laser with laser parameters required for stapedotomy., Methods: After opening the bulla, the basal convolution of the guinea pig cochlea, whose thickness is similar to that of the human stapes footplate, was irradiated with the Er:YSGG and Ho:YAG laser. The laser parameters used were those necessary for an adequate perforation of a human stapes footplate (500-600 microns). The cochleae were removed 90 minutes, 1 day, 2 weeks, or 4 weeks after laser application. The organ of Corti was examined by scanning electron microscopy in all convolutions., Results: Application of Er:YSGG laser parameters effective for stapedotomy (5 pulses, energy: 85 J/pulse, energy density: 36 J/cm2, total energy: 0.425 J) had no adverse effects on the organ of Corti in the guinea pig cochlea. On the other hand, effective Ho:YAG laser parameters (10 pulses, energy: 210 J/pulse, energy density: 90 J/cm2, total energy: 2.1 J) caused damage to the outer hair cells with fusion of stereocilia and formation of giant cilia leading to partial or total cell loss. The inner hair cells and supporting cells were usually normal., Conclusion: Our results clearly demonstrate that the Er:YSGG laser has high application safety. It could prove to be a viable alternative to the thermically acting CO2 laser for stapedotomy. The Ho:YAG laser is not well tolerated in animals and has low application safety. Its use in stapedotomy would be unreliable and dangerous for the inner ear.

Experiments were performed in guinea pigs to clarify which, if any, of the CO2 lasers used can damage the inner ear on application of the laser parameters required for stapedotomy. A further aim was to determine their application safety. The basal convolution of the guinea-pig cochlea was chosen as the application site, since its thickness is similar to that of the human stapes base. We examined the laser effect in connection with perforation of the basal convolution and subsequent application in the open cochlea. Acoustic evoked potentials (compound action potentials [CAP]) yielded information on inner-ear function. Animals without laser treatment were used as controls. Perforation of the basal convolution and laser applications in the open cochlea with the same parameters did not lead to a measurable CAP alteration with the CO2 cw laser (power: 8 W, pulse duration: 50 ms, power density: 3200 W/cm2). An increase of the laser power to 15 W (power density: 6000 W/cm2) and of the pulse duration to 200 and 500 ms (energy: 3 J and 7.5 J) caused partly irreversible CAP alterations; finally, no potential could be recorded any more at a maximal laser power and pulse duration (15 W and 500 ms). Examination of high power densities (40,000 and 60,000 W/cm2) through reduction of the laser beam diameter to 180 microns yielded comparable results.(ABSTRACT TRUNCATED AT 250 WORDS)

The Erbium:YAG-laser is a good tool for microresection of bone and soft tissue from the ear drum, to the ossicles and extending to the footplate. The mechanism of ablation is based on the fact that the emission of infrared light is of the same wavelength at which water has its peak of optimal light absorption. 14% of bone is water, just sufficient force for ablation. At 50 mJ impulses the temperature in the centre stays below the coagulation point. 500 impulses of 50 mJoule definitely remain below the acoustic risk. In 44 guinea pigs 500 x 50 mJ caused a temporal threshold shift of maximal 38 dB at 2000 cps which recovered after 90-135 min. In 60 tympanoplasties neither tinnitus nor audiological side effects of the laser application were measured. The ear drum is perforated by 1 (-3) impulses. This can be done even in children after superficial anaesthesia (2% pantocaine drops) to drain the middle ear. The laser perforation of 0.3 mm [symbol: see text] will close after a day and has to be re-opened in the office to avoid tubes. We do not yet know how often general anaesthesia and removal by suction of too viscous mucus remain nevertheless necessary. With the Er:YAG laser parts of the ossicles can be cut out of the intact chain, without contact and trauma, nearly without loss of bone tissue. This allows better radicality in removing cholesteatomas or scars with less destruction. 500 impulses of 50 mJ ablate 32 mg of bone, i.e. the weight of an incus.(ABSTRACT TRUNCATED AT 250 WORDS)

In a recent textbook concerning ear surgery, it is recommended to put some connective tissue on the stapes footplate before introducing a TORP. This should avoid penetration of the shaft of the TORP into the inner ear. Experimental studies were performed to estimate the pressure needed for pushing a TORP through the footplate. We found those pressures to be much higher than those which might occur by increasing pressure in the external ear canal or decreasing pressure in the middle ear. This means that perforations of the footplate are not due to one big event of changing pressure, but rather by chronic irritations or foreign body reactions. Anyhow, we consider the protection of the footplate by a layer of connective tissue to be very useful.