Safety of the erbium:yttrium-aluminum-garnet laser in stapes surgery in otosclerosis

Creation of an incus recess for a middle-ear microphone using a drill or laser ablation: a comparison of equivalent noise level and middle ear transfer function

PURPOSE

Studies have assessed the trauma and change in hearing function from the use of otological drills on the ossicular chain, but not the effects of partial laser ablation of the incus. A study of the effectiveness of a novel middle-ear microphone for a cochlear implant, which required an incus recess for the microphone balltip, provided an opportunity to compare methods and inform a feasibility study of the microphone with patients.

METHODS

We used laser Doppler vibrometry with an insert earphone and probe microphone in 23 ears from 14 fresh-frozen cadavers to measure the equivalent noise level at the tympanic membrane that would have led to the same stapes velocity as the creation of the incus recess.

RESULTS

Drilling on the incus with a diamond burr created peak noise levels equivalent to 125.1-155.0 dB SPL at the tympanic membrane, whilst using the laser generated equivalent noise levels barely above the baseline level. The change in middle ear transfer function following drilling showed greater variability at high frequencies, but the change was not statistically significant in the three frequency bands tested.

CONCLUSIONS

Whilst drilling resulted in substantially higher equivalent noise, we considered that the recess created by laser ablation was more likely to lead to movement of the microphone balltip, and therefore decrease performance or result in malfunction over time. For patients with greatly reduced residual hearing, the greater consistency from drilling the incus recess may outweigh the potential benefits of hearing preservation with laser ablation.

Picosecond Infrared Laser (PIRL) Application in Stapes Surgery-First Experience in Human Temporal Bones

Objective:

Using a contact-free laser technique for stapedotomy reduces the risk of mechanical damage of the stapes footplate. However, the risk of inner ear dysfunction due to thermal, acoustic, or direct damage has still not been solved. The objective of this study was to describe the first experiences in footplate perforation in cadaver tissue performed by the novel Picosecond-Infrared-Laser (PIRL), allowing a tissue preserving ablation.

Patients and Intervention:

Three human cadaver stapes were perforated using a fiber-coupled PIRL. The results were compared with footplate perforations performed with clinically applied Er:YAG laser. Therefore, two different laser energies for the Er:YAG laser (30 and 60 mJ) were used for footplate perforation of three human cadaver stapes each.

Main Outcome Measure:

Comparisons were made using histology and environmental scanning electron microscopy (ESEM) analysis.

Results:

The perforations performed by the PIRL (total energy: 640–1070 mJ) revealed a precise cutting edge with an intact trabecular bone structure and no considerable signs of coagulation. Using the Er:YAG-Laser with a pulse energy of 30 mJ (total energy: 450–600 mJ), a perforation only in the center of the ablation zone was possible, whereas with a pulse energy of 60 mJ (total energy: of 195–260 mJ) the whole ablation zone was perforated. For both energies, the cutting edge appeared irregular with trabecular structure of the bone only be conjecturable and signs of superficial carbonization.

Conclusion:

The microscopic results following stapes footplate perforation suggest a superiority of the PIRL in comparison to the Er:YAG laser regarding the precision and tissue preserving ablation.

Stapedotomy with Microdrill or Carbon Dioxide Laser: Influence on Inner Ear Function

Objectives:

A prospective randomized audiological analysis of 336 otosclerosis operations was conducted to compare the evolution of bone conduction thresholds after primary stapedotomy with Two different techniques to open the footplate: microdrill and carbon dioxide laser stapedotomy.

Methods:

To monitor the inner ear function, we compared the preoperative bone conduction thresholds with the postoperative levels at day 2, week 2, week 6, and month 6. Evolution of the bone conduction was compared for the Two studied groups (laser versus microdrill).

Results:

An average bone conduction loss of 1.8 dB was measured at day 2 for the middle frequencies (0.5, 1, and 2 kHz). At 4 kHz, a bone conduction loss of 7 dB was found. The bone conduction thresholds measured in the first and second months after surgery showed a gradual recovery with overclosure as the end result.

Conclusions:

Our results confirm the transient depression of inner ear function in the immediate postoperative period, with recovery within the first weeks after surgery. In the studied population, no statistically significant difference was found between the Two techniques that were used to make the calibrated hole (laser versus microdrill). These results demonstrate that both techniques possess the same early effect regarding inner ear function. The authors hypothesize that an early inflammatory reaction could be the cause of the transient bone conduction shift.

Erbium: Yttrium-Aluminum-Garnet Laser Application in Stapedotomy

OBJECTIVE: To assess clinical safety and efficacy of the erbium: yttrium-aluminum-garnet (Er:YAG) laser in the stapes surgery; to define and optimize parameters that render the procedure safe for the inner ear.

STUDY DESIGN: Retrospective study.

MATERIAL AND METHODS: A microscope-integrated Er: YAG laser stapedotomy was performed on 29 patients and a conventional stapedotomy on 41 patients. An early (within 1 to 3 days after stapes surgery) and late (at least 6 weeks) pure-tone bone-conduction threshold audiogram was obtained.

RESULTS: No statistically significant differences were found by Student's t test over all measured frequencies between pre- and postoperative bone-conduction thresholds in each group. There was no statistically significant difference for all frequencies between early (3 days) and late postoperative mean bone-conduction thresholds.

CONCLUSIONS: The results of our preliminary clinical study showed that erbium laser poses no risk to inner ear function. However, the lack of standardization obliges further investigation to establish safe clinical parameters of the Er:YAG laser.

EBM RATING: B-3

CO2 Laser Stapedotomy with the “One-Shot” Technique— Clinical Results

OBJECTIVE: To further optimize the surgical technique with the CO2 laser in stapes surgery a scanner system was used to obtain a footplate perforation of 0.5 to 0.6 mm with only 1 laser application (“one-shot” stapedotomy).

STUDY DESIGN: 188 patients with otosclerosis were submitted to a primary CO2 laser stapedotomy with the SurgiTouch® scanner. This study surveys 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 with the SurgiTouch® scanner. In 11% of the patients, a second laser application at the same site was necessary. In 21% of the patients, the perforation had to be enlarged by several slightly overlapping laser applications without scanner. The clinical data of this study clearly documents that there is no evidence of laser depending inner ear affections.

CONCLUSION: The CO2 laser combined with modern scanner systems is well suited for application in stapes surgery.

[Pilot study on the diode laser in stapes surgery]

Stapes surgery has a long history. While the results are good, there is a possibility of complications that can lead to a worsening of hearing. The objective of this study was to study hearing in patients undergoing surgery using 980 Nm Diode laser in the immediate postoperative period. In no case was the bone threshold worse in the first audiometry control at 10 days of surgery. The use of a 980 Nm Diode laser thus minimises the chance of stapes footplate fracture with risk of its drop in the labyrinth. A thick stapes can be operated on without the trauma produced by drilling it. By facilitating the surgical procedure, stapes surgery with a 980 Nm Diode laser reduces the possibility of complications.

A comparison of the hearing results of KTP and Erbium YAG laser stapedotomy

CONCLUSION

Our data prove that lasers are safe and useful instruments in stapes surgery. Good postoperative results can be attained in both KTP and Er: YAG lasers. There was no significant inner ear damage related to the Er: YAG laser use.

OBJECTIVE

To compare the postoperative results of stapedotomies performed with KTP and Erbium: YAG lasers in patients with otosclerosis in order to assess the risk of Er: YAG for the inner ear.

PATIENTS AND METHODS

The charts of 152 consecutive adult patients who underwent primary laser stapedotomies for otosclerosis from 1999 to 2005 were reviewed. One hundred and thirty-seven stapedotomies (98 patients) were performed using the KTP laser and 54 stapedotomies (54 patients) were performed with Er: YAG laser. All the patients were separated in two groups according to the type of laser, which was used. Hearing results were analyzed according to the Committee on Hearing and Equilibrium Guidelines of the American Academy of Otolaryngology-Head and Neck Surgery. Pure-tone audiometry was performed before the surgery, three months and one year postoperatively.

RESULTS

The study indicated that KTP and Er: YAG stapedotomies have similar rates of the air-bone gap closure. There was no significant postoperative sensorineural hearing loss found in both techniques.

Erbium: yttrium-aluminum-garnet laser stapedotomy—A safe technique

Objective

To standardize the technical parameters of the erbium: yttrium-aluminum-garnet (Er:YAG) laser stapedotomy.

Study Design

Retrospective study of all patients with otosclerosis who underwent stapedotomy from January 2002 to January 2006.

Subjects and Methods

The charts of 152 consecutive patients who underwent stapedotomy were reviewed. The patients were stratified into two groups, according to the instrument used. Stapedotomies were performed in group A, with the OPMI®TwinEr: YAG laser; and in group B with manual microperforators.

Results

No statistically significant differences were found over all measured frequencies, between pre- and postoperative bone conduction thresholds, in each group. At the last postoperative follow-up, vertigo and nystagmus were not detected; two patients in group A and one patient in group B showed persistent tinnitus.

Conclusion

Er:YAG laser stapedotomy is a safe and effective procedure, with no damage of the inner ear when strict adherence to the safety parameters is observed. The Er:YAG laser is definitively suitable for stapes surgery, and represents a useful and safe tool in the armamentarium of otological microsurgery.

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.

„Ein-Schuss-CO2-Laser-Stapedotomie“

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.

Morphological effects of nanosecond- and femtosecond-pulsed laser ablation on human middle ear ossicles

We evaluate the feasibility of nanosecond-pulsed and femtosecond-pulsed lasers for otologic surgery. The outcome parameters are cutting precision (in micrometers), ablation rate (in micrometers per second), scanning speed (in millimeters per second), and morphological effects on human middle ear ossicles. We examine single-spot ablations by a nanosecond-pulsed, frequency-tripled Nd:YAG laser (355 nm, beam diameter 10 microm, pulse rate 2 kHz, power 250 mW) on isolated human mallei. A similar system (355 nm, beam diameter 20 microm, pulse rate 10 kHz, power 160-1500 mW) and a femtosecond-pulsed CrLi:SAF-Laser (850 nm, pulse duration 100 fs, pulse energy 40 microJ, beam diameter 36 microm, pulse rate 1 kHz) are coupled to a scanner to perform bone surface ablation over a defined area. In our setups 1 and 2, marginal carbonization is visible in all single-spot ablations of 1-s exposures and longer: With an exposure time of 0.5 s, precise cutting margins without carbonization are observed. Cooling with saline solution result is in no carbonization at 1500 mW and a scan speed of 500 mms. Our third setup shows no carbonization but greater cutting precision, although the ablation volume is lower. Nanosecond- and femtosecond-pulsed laser systems bear the potential to increase cutting precision in otologic surgery.

Prospective clinical study on cochlear function after erbium:yttrium-aluminum-garnet laser stapedotomy

OBJECTIVE

To assess whether the application of the emitting erbium:yttrium-aluminum-garnet (Er:YAG) laser in stapedotomy has negative effects on vestibular and cochlear functions.

DESIGN

Prospective, with 12 to 14 months follow-up.

SETTING

Academic tertiary referral center.

PATIENTS

Twenty-four patients undergoing stapedotomy (primary surgery) in otosclerosis.

INTERVENTION

All patients underwent Er:YAG laser-assisted stapedotomy for otosclerosis between January 2000 and June 2002.

MAIN OUTCOME MEASURES

Early (1-3 days after surgery) and late (12-14 months after surgery) postoperative bone-conduction thresholds and the presence of post-operative tinnitus and vertigo were analyzed. In addition, the relation between applied laser energy and postoperative bone-conduction thresholds was calculated.

RESULTS

In 22 patients, unchanged preoperative minus early postoperative pure-tone bone-conduction averages at 1, 2, and 4 kHz were observed. In one patient, a slight early deterioration between 10 and 20 dB was seen. In 18 patients, unchanged preoperative minus late postoperative pure-tone bone-conduction averages at 1, 2, and 4 kHz were observed. In two patients, a slight late deterioration between 10 and 20 dB was seen. In two patients, a new postoperative tinnitus was observed. No patient suffered from vertigo at the time of second evaluation. No correlation between applied laser energy and both postoperative bone-conduction thresholds was found.

CONCLUSIONS

The Er:YAG laser stapedotomy in otosclerosis is a safe technique. Vestibular and cochlear function is not significantly disturbed after Er:YAG laser stapedotomy.

Revision stapedectomy

During the past decade, the evolution of surgical techniques and philosophy for revision surgery after stapedectomy has accelerated. Lasers, new surgical techniques, and new prostheses now permit the precise identification and reliable correction of the conductive problem, while reducing the risk of postoperative sensorineural hearing loss that plagued nonlaser revision techniques.