Objective Measurements of Ossicular Chain Mobility Using a Palpating Instrument Intraoperatively.

BACKGROUND: The judgment of a normal or impaired mobility of middle ear ossicles is based on palpation and depends highly on the surgeon's subjective experience. The aim of this study was to develop and test a palpating instrument recording force and vector and allowing to support the surgeon's subjective impression with objective measurement results. STUDY DESIGN: Prospective recordings at surgery. SETTING: Tertiary referral center. PATIENTS AND METHODS: A fiberoptic force-sensing element allowing force measures in three orthogonal directions was integrated into a handheld 45 degree hook and tested in temporal bones. Clinical data series from patients with a functionally normal chain (e.g., cochlear implants (CI)) and impaired ossicles (otosclerosis) were collected. The ossicles were palpated until their first movements out of the resting stage were visualized, the applied force, and vector were recorded by an independent observer. RESULTS: Four CI and 19 otosclerosis patients were further evaluated. The minimum detectable force change of the sensor was 0.2 gF (2 mN). In the otosclerosis patients the average force applied to move the malleus was 9.5 gF, on the incus 8.7 gF. These values were slightly lower after separation of the incudostapedial joint, reaching 8.5 gF and 6.9 gF, respectively. The fixed stapes showed a rigidity of 14.7 gF or higher. The values were lower in the CI group measuring 4.4 gF, 4.1 gF, and 3.3 gF on the three ossicles, respectively. CONCLUSIONS: We were able to produce a disposable, easy-to-handle palpating probe that enables the otologist to record continuously tip contact forces in three dimensions during his standard palpation of each ossicle. Normative values were reproduced for each ossicle, as well as increased rates for stapes fixation in otosclerosis.

Comparison of KTP, Thulium, and CO2 laser in stapedotomy using specialized visualization techniques: thermal effects.

High-speed thermal imaging enables visualization of heating of the vestibule during laser-assisted stapedotomy, comparing KTP, CO2, and Thulium laser light. Perforation of the stapes footplate with laser bears the risk of heating of the inner ear fluids. The amount of heating depends on absorption of the laser light and subsequent tissue ablation. The ablation of the footplate is driven by strong water absorption for the CO2 and Thulium laser. For the KTP laser wavelength, ablation is driven by carbonization of the footplate and it might penetrate deep into the inner ear without absorption in water. The thermal effects were visualized in an inner ear model, using two new techniques: (1) high-speed Schlieren imaging shows relative dynamic changes of temperatures up to 2 ms resolution in the perilymph. (2) Thermo imaging provides absolute temperature measurements around the footplate up to 40 ms resolution. The high-speed Schlieren imaging showed minimal heating using the KTP laser. Both CO2 and Thulium laser showed heating below the footplate. Thulium laser wavelength generated heating up to 0.6 mm depth. This was confirmed with thermal imaging, showing a rise of temperature of 4.7 (±3.5) °C for KTP and 9.4 (±6.9) for Thulium in the area of 2 mm below the footplate. For stapedotomy, the Thulium and CO2 laser show more extended thermal effects compared to KTP. High-speed Schlieren imaging and thermal imaging are complimentary techniques to study lasers thermal effects in tissue.

Piezoelectric stapedotomy: the importance of a micropulse program.

CONCLUSIONS: We can consider the micropulse program as the best level of safety that should be used in all cases of piezoelectric stapedotomy. OBJECTIVES: The aim of this study was to describe the importance of a micropulse program in determining the success of piezoelectric stapedotomy. METHODS: A total of 112 patients (group A) affected by primary otosclerosis underwent piezoelectric stapedotomy for otosclerotic stapes fixation. A specific operative program was created to perforate the stapes footplate: this program makes it possible to perforate the footplate of the stapes with a predetermined and non-modifiable temporization. Before and 1 year after surgery, all the patients underwent the following instrumental examinations: pure-tone audiometry, tympanometry, transient-evoked otoacoustic emissions, distortion product otoacoustic emissions, and auditory brainstem response. Results were compared with those obtained from 30 patients who underwent piezoelectric stapedotomy without the specific operative program (group B). RESULTS: At 1 year after surgery, with regard to the pure-tone audiometry test, all patients had an air-bone gap (ABG) reduction: no worsening of the bone conduction and no postoperative sensorineural hearing loss were found. In group A, there was a closure of the ABG within 10 dB in all patients.

Piezoelectric bone surgery in otosclerosis.

CONCLUSION: This test of the Piezosurgery medical device for osteoplasty of the external auditory duct posterior wall and stapedotomy highlighted the advantages of this device. The device's accuracy and selectivity render it superior to conventionally rotating instruments in otologic surgery. The precise nature of the instrument allows exact, clean, and smooth cut geometries during surgery, without any visible injury to the adjacent soft tissue. OBJECTIVE: The aim of this work was to test the Piezosurgery device as a new and alternative method to conventional bone tissue management in otologic surgery and in particular in stapedotomy and the external auditory duct posterior wall. MATERIALS AND METHODS: The Piezosurgery medical device is a piezoelectric ultrasonic bone-cutting surgical instrument designed to perform sharp cutting actions. The equipment consists of two piezoelectric hand-pieces and two insets that are connected to a main unit, which supplies power and has holders for the hand-piece and irrigation fluids. Piezosurgery uses low frequency ultrasonic waves (24.7-29.5 kHz), the applied power can be modulated between 2.8 and 16 W, and the machine is programmed in accordance with the density of the bone cut. The micro-vibrations that are created in the piezoelectric hand-piece cause the inserts to vibrate linearly between 60 and 210 microm and allow a selective cut of mineralized tissues without trauma to soft tissues. The interoperative irrigation cools down the bone surface and make the operating site blood-free. Twenty patients affected by otosclerosis underwent treatment utilizing the device. RESULTS: In all the patients treated, the characteristics of the ultrasonic frequencies allowed rapid and easy intraoperative management, without any visible injury to the adjacent soft tissue. No side effects were detected.

Assessment of stapes mobility by use of a newly developed piezoelectric ceramic device. A preliminary experiment in dogs.

A piezoelectric device was developed for assessment of stapes mobility during middle ear surgery. The device comprises a pair of ceramic bimorph elements: one for activation of the stapes and the other to pick up the vibration as an electric output, which varies in accordance with the stapes mobility, ie, the inverse of the cochlear input impedance (Zsc). The device is compact and easily manipulated even in the narrow surgical field of the ear. However, the measuring range is restricted to between 1 and 10 kHz. Measurement of Zsc was conducted with this device in 5 ears of 5 dogs. The mean magnitude of Zsc increased with frequency in the range from 1 to 10 kHz: 0.95 megohm at 1 kHz and 8.8 megohms at 10 kHz. After fixation of the stapes with dental cement, the magnitude increased to more than 10 megohms, except at 1 kHz. The results suggest that the device is useful in detecting decreases in stapes mobility in patients with chronic otitis media.

[Stapotomy with ultrasound? Animal experiment study of possible side effects]. / Stapedotomie mit Ultraschall? Tierexperimentelle Untersuchung möglicher Nebenwirkungen.

Stapedectomy by ultrasound has been proposed as an alternative method for perforating the stapes footplate in surgery for otosclerosis. Possible functional adverse effects of ultrasound perforation of the otic capsule in guinea pigs were investigated in the present study by means of vestibular evoked potentials (VsEP). VsEP were elicited by pulsed linear accelerations applied to the animal's head following surgical removal of the middle ear, following intense ultrasound drilling around the otic capsule and after drilling a small hole in the anterior bony wall of the vestibule. All manipulations did not affect amplitudes and latencies of the early potential N1 (less than 1 msec after onset of acceleration). Significant alterations of N1 occurred following direct mechanical damage of the otolithic organs, indicating that VsEP can be used to detect lesions of these receptors and therefore may be used as a parameter of vestibular function in experimental animals. Findings indicate that perforation of the otic capsule by ultrasound is possible without inducing functional lesions of the otolithic organs.