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Background: Coupling of the prosthesis to the long process of the incus is a critical step in stapes surgery. We report first experiences with the NiTiFLEX® stapes prosthesis, a further development of the Soft CliP® stapes prosthesis (Kurz, Dusslingen, Germany). Instead of pure titanium, the CliP® now consists of nitinol, a superelastic nickel-titanium alloy. This further reduces the pressure exerted on the long process of the incus, aiming to improve coupling and minimize the risk of incus luxation., Methods: In a monocentric, retrospective cohort study, we evaluated air-bone gap reduction (4PTA0.5-4 kHz), understanding of monosyllables at 65 and 80 dB SPL stimulation levels, and adverse effects, such as changes in bone conduction (4PTA0.5-4 kHz). During a 12-month period (May 2014 to April 2015), stapes surgery was performed in 21 otosclerosis patients using the NiTiFLEX® prosthesis. The footplate was perforated using a CO2 laser (scanning mode; 0.7 mm; 20-21 W) in almost all cases. The diameter of the titan piston was 0.4 mm. Immersion at an angle of almost 90° thus results in a gap between the footplate perforation and the piston of 0.15 mm. Positioning onto the long incus process was performed with a 90°microhook (0.6 mm)., Results: In all cases the NiTiFLEX® stapes prosthesis was inserted without complications. The mean bone conduction threshold did not change significantly postoperatively and the mean air-bone gap (4PTA0.5-4 kHz) improved on average from 29.0 to 9.5 dB HL. Handling of the prosthesis was rated as very good., Conclusion: The limited experience of this study suggests that the NiTiFLEX® stapes prosthesis is a successful further development of the Soft CliP® technique with very good intraoperative handling qualities. While long-term results from larger studies are needed, this case series demonstrates that the hearing outcome is comparable to other prostheses.

Introduction: Surgical accuracy in microscopic ear surgery is reduced by limited access and tremor. At this point a micromanipulator could have a positive influence. The goal of the study was: 1. To develop a system that would enable measurements of accuracy, time and precision during a manual approach to the middle ear 2. To apply a manipulator that can easily be a compact part of the regular setup in ear surgery 3. To compare the manual results critically considering accuracy and tremor reduction and to compare these results with those of a manipulator A manipulator in ear surgery does not need to be a highly complex structure with force feedback and multiple degrees of freedom. The surgeon's preparation in middle ear surgery is most of the time straight without potentially applying the 15 degrees of freedom the human hand can offer. The micromanipulator in this study was developed in order to serve as a compact, teleoperated instrument without limiting the surgeon's dexterity. The use of standard instruments facilitates the integration of the system in existing surgical procedures and sterilisation concepts., Material and Methods: Ten head and neck surgeons simulated an approach to the stapedial footplate on a modified 3D cast of a realistic human skull in an experimental OR. A perforator was moved to a reference point on the stapedial footplate. The movements were detected by means of an image acquisition system. Each trial was repeated more than 200 times, aiming both manually and with the aid of a micromanipulator (> 4,000 measurements)., Results: Accuracy for the manual and micromanipulator approach revealed no considerable differences. In absolute terms, the manual approach was more accurate. However, the learning curves indicated a stronger decrease in deviation when the micromanipulator was used and also less deviation in scatter plots. At the beginning, the time required for pointing increased when using the micromanipulator, but decreased to a greater extent in the course of the trial when compared to the manual approach. The work strain was distinctively lower when the micromanipulator was applied., Conclusion: The micromanipulator gave evidence of a stronger effect as regards individual improvement in accuracy and time span. The micromanipulator shows potential for improvements in accuracy as well as compensation for poor ergonomics.

In addition to hearing aids, stapesplasty represents the standard treatment of otosclerosis-induced hearing loss. In this procedure, the stapes superstructure is replaced by a prosthesis that is attached to the long process of the incus and communicates through a perforation in the footplate with the perilymphatic space of the inner ear. The removal of the stapes superstructure and perforation of the footplate are the critical steps of this surgical procedure. With the introduction of laser-assisted perforation techniques, the surgical safety of this method has been improved compared to conventional techniques. KTP, argon, as well as diode, Er:YAG and CO(2) lasers are used for stapedotomy. By using the CO(2) laser in conjunction with a scanner system, the number of laser applications required for the perforation of the footplate has been markedly reduced. In contrast to other systems, a more reproducible perforation diameter of the stapes footplate is achieved with a CO(2) laser equipped with a scanner. Complications such as uncontrolled leakage of perilymph, irradiation of inner ear structures or the occurrence of pressure waves with subsequent damage to the inner ear can be reduced by using a CO(2) laser. In this review, the surgical technique of CO(2) laser stapedotomy, including clinically established variants and paying particular attention to the one-shot technique, are described and discussed in comparison to other laser systems.

Background: The first hearing results with a new stapes prosthesis with clip function (Soft-CliP(R) piston) are presented., Patients and Methods: This new prosthesis was used in 15 patients (mean age 45.2 years; range 21-63 years) undergoing routine stapes surgery. Soft-CliP(R) piston prostheses with a shaft diameter of 0.4 mm and a length ranging from 4.25 mm to 5.5 mm were used. Postoperative audiological testing and measurement of the air-bone gap were performed after an average of 47.3 days and compared with the preoperative values., Results: The median observed postoperative air-bone gap (ABG) was 8.33 dB +/-4.16 dB. All patients had less than 20 dB ABG and in 53.3% of cases was less than 10 dB. The operating time showed a clear difference between the left (66.5 min +/-37.79 min) and right ears (47.2 min +/-11.08 min)., Discussion: This new prosthesis design greatly facilitates a very difficult step in stapes surgery, the prosthesis fixation to the incus. The first postoperative hearing results are very promising but long-term results in a larger group of patients are still pending.

Otosclerosis can be of viral origin and in 25-50% of cases a familiar accumulation can be seen. Typically patients develop a progressive middle ear hearing loss which starts in young adulthood and which can affect one as well as both ears in up to 80% of cases. The surgical procedures of choice are stapedotomy and stapedectomy. Complications of surgery are persistent vertigo, secondary facial nerve palsy and the most severe complication is deafness in up to 1% of the cases. Even if the operation risks are low, the alternative use of a hearing aid must be offered in the initial consultation. A new technique of stapes surgery is laser-assisted stapedotomy. Necrosis of the incus process with dislocation of the prosthesis is the most common finding which necessitates stapes revision surgery. The aim of this article is to present the current scientific concept, diagnostics and therapy of otosclerosis with an emphasis on surgical treatment options.

Background: The aim of this study was to describe a new stapes prosthesis with memory characteristics for wire crimping (SMart-Piston)., Patients and Methods: This technique was used in 15 patients (mean age 43.4 years; range 28-71) undergoing routine stapes surgery. SMart-Piston prostheses with a shaft diameter of 0.5 mm and length ranging from 4.25-4.5 mm were used. Heat induced wire crimping was performed by CO2 laser in five patients, and by bipolar diathermy forceps in ten patients. In 15 patients, postoperative audiological testing was performed at an average 21.9 days and in another 10 again after 435 days following surgery., Results: The median observed air-bone-gap (ABG) postoperatively was 8.7 dB+/-7.7 dB. A total of 73% of all patients had an ABG of 10 dB or less, and all patients had less than 20 dB. In the ten patients controlled after 435 days, the ABG was 4.4 dB+/-2.4 dB. It was lower than 10 dB in all individuals., Discussion: A critical point in every stapes surgery, the prosthesis fixation to the incus, is greatly facilitated by this novel technique. Long-term results in a larger group of patients are pending.

Background: In order to further optimize the surgical technique with CO(2) laser in stapes surgery, a scanner system was used to obtain a footplate perforation of 0.5-0.6 mm with only one laser application ("one-shot" stapedotomy)., Patients and Methods: A total of 255 patients with otosclerosis were submitted to primary CO(2) laser stapedotomy with a SurgiTouch scanner. This study discusses the surgical technique and clinical results., Results: An adequately large perforation diameter could be achieved with a single shot in 68% of the patients treated. In 14% of the patients, a second laser application at the same site was necessary. In 18% the perforation had to be enlarged by several slightly overlapping laser applications without using the scanner. There was no evidence of laser dependent inner ear affections., Conclusion: CO(2) laser, combined with modern scanner systems, is well suited for application in stapes surgery.

Apart from ablation properties at the stapes footplate, the degree of thermal stress of the inner ear is important when considering the suitability of pulsed lasers for stapedotomy. The aim of the present study was to compare the heating of cochlear structures with presently available pulsed laser systems during stapedotomy under reproducible conditions. Temperature increases and heat-exchange processes were examined in a physiologic model of the cochlea using various laser parameters effective for footplate perforations. With all systems, increases in energy density, number of pulses and resultant total energy led to higher temperatures. In the effective energy density range, the highest temperature increases achieved with the requisite number of pulses at a distance of 2 mm behind the footplate perforation were 30 degrees and 26 degrees C with the pulsed CO2 and Ho:YAG lasers, respectively. The lowest temperature recorded was 5.5 degrees C with the Er:YAG and <5 degrees C with the Er:YSGG laser. The excimer laser investigated at only one energy density showed maximum temperatures of 10 degrees C. With regard to possible inner ear damage from thermal stress during laser stapedotomy, the Er:YSGG laser can be used safely over a relatively broad energy density range. The Er:YAG laser investigated also appears suitable for stapedotomy when considering thermal effects. In contrast, application of the pulsed CO2 laser at parameters effective for stapedotomy leads to high temperatures and wide scattering to compromise its use. The Ho:YAG laser also appears to be unsuitable because of the higher energy density and pulse rate required for sufficient perforation and the resultant higher temperature increases in the perilymph. Although footplate perforations can be achieved with only slight temperature increases in the fluid of the cochlea model, the excimer laser does not seem to be appropriate for stapedotomy because of the long period of heat exposure required and the lower ablation rates at the stapes.

As a consequence of perforating the footplate during laser stapedotomy, direct radiation to the inner ear will warm perilymph and adjacent structures. To determine the possible thermal dangers to cochlear structures from different laser parameters, heat transport mechanisms, temperature increases and temperature fields were investigated in a model system approximating caloric and physiologic changes in the inner ear. The temperature-time course of local cochlear warming showed a rapid convection-dependent increase that reached a peak at about the end of the laser impulse. An increase in power density caused an elevation of the temperature in all laser systems used. Maximum temperatures varied widely for CO2 lasers at the same wave-length, but a different beam-time behavior was found at a distance of 2 mm behind the perforation by using low-power densities. Heat values were lowest at a pulse duration of 50 ms in the superpulse (< 5 degrees C) and continuous wave (cw) modes (< 9 degrees C), while the highest value was found in the pulser mode (to 21 degrees C). After argon laser irradiation at high-power densities, temperatures were nearly independent of location (5.5-13 degrees C). When considering risks of possible inner ear damage from thermal stress during laser stapedotomy, application of the CO2 superpulse and cw laser appears to be safe over a large power-density range. Low energies using a small-beam diameter and short pulse durations (50-100 ms) are recommended. In contrast, use of the CO2 laser in a pulser mode may result in inner-ear damage because of the high temperatures produced. Structures located at a greater distance can be endangered by direct irradiation with the argon laser.

The object of the present study was to examine the tissue ablation capacity of various pulsed lasers at the stapes footplate. Isolated human stapes and bovine compact-bone platelets (thickness 90 microns) were used to determine effective laser parameters for achieving a perforation measuring 500 microns to 600 microns in diameter. Apart from achieving the perforation diameters, particular attention was given to the form and quality of the perforations, reproducibility of the perforation effect and the thermally altered border zones occurring at the footplate. Four pulsed laser systems were used: excimer, Ho:YAG, Er:YSGG and CO2 lasers. An adequately large perforation generally could only be achieved by several repeated shots at the same application site, since only a small amount of tissue was ablated per application. The mechanism of the photoablation caused the extent of the thermal side effects to be markedly lower than with the continuous wave (cw) and superpulse systems. For this reason and because of their highly reproducible perforation effect, they were basically better suited for stapedotomy than the cw systems. It was possible, however, that as a result of the longer application time and the need to repeatedly irradiate the same application site, the higher pulse counts could prove to be disadvantageous in clinical practice. Among the pulsed laser systems, the Er:YSGG laser had the highest ablation rate at the stapes and was thus the most effective laser for interventions at the footplate. Although somewhat less effective than the Er:YSGG laser in our studies, the Ho:YAG and pulsed CO2 lasers also appear to be suitable for stapes surgery. On the other hand, we did not consider the excimer laser (308 nm) to be particularly effective at the footplate because of its low ablation rates.

During stapedotomy, the small dimensions and highly sensitive anatomic structures present require the highest degree of precision and safety. The risk of damage to middle and inner ear structures through manipulation with conventional instruments can be reduced by non-contact perforation of the footplate with the laser beam. The present study was devised to clarify which of the presently available laser systems was best suited for use in stapes surgery and thus represent a significant alternative to conventional stapedotomy. Isolated human stapes and bovine compact-bone platelets were used to investigate the connections between the parameters of various laser systems and their effects on bone tissue. The aim was to optimize the laser parameters required to achieve a perforation of 500 microns to 600 microns in diameter. In addition, the thermal effects of laser irradiation were assessed. Three different systems were employed: the argon and CO2 lasers in continuous wave (cw) modes and the CO2 laser in superpulse mode. The lasers investigated offered the advantage of achieving an adequately large perforation with one or a few juxtaposed applications but caused in part extensive thermal side effects at the stapes footplate. To reduce thermal effects, footplate perforation was best performed by several juxtaposed single shots at low power, short pulse duration and small beam diameter. The suitability of the argon laser for stapedotomy was rendered doubtful in view of the lower absorption coefficient of the stapes for the argon laser beam and the considerable influence exerted by the degree of pigmentation of the irradiated tissue sites with a resultant poor reproducibility of the perforation diameter.(ABSTRACT TRUNCATED AT 250 WORDS)