Experimental and clinical results of Er:YAG laser stapedotomy

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.

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.

Lasers in stapes surgery: a review

Background:

Lasers in stapes surgery are used to divide the anterior and posterior crus of the stapes, divide the stapedius tendon and perforate the footplate. The ideal laser should not penetrate deeply into the perilymph (thereby increasing its temperature). It should be conducted through optical fibres, allowing easy manipulation, and should have good water absorption, equating to high bone ablation efficiency.

Objectives:

This review discusses the various different lasers used in stapes surgery with regard to their properties and suitability for this type of surgery. In particular, the laser parameters used are discussed to facilitate their clinical use.

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.

„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.

[Stapedotomy, stapedectomy and revision surgery performed with laser techniques. Revision of literature]

The usefulness of laser in otologic surgery, and specifically the suitability of its use in stapes surgery, is still under discussion. We intend to support the use of this method in the surgical treatment of otosclerosis, as well as to elucidate which type of laser is the most advisable one, establishing also in which stages of surgery it should be used. For this, we carry out a revision of the main opinions published in this regard in the international literature, commenting on the results and observations gathered in it. We end by setting out a number of conclusions which are the result of the analysis of the criteria put forward in the bibliography.