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A compact high energy co-doped Tm:Ho:YAG Q-switched laser side-pumped by the 785 nm quasi-continuous wave (QCW) laser diodes (LDs) at room temperature is demonstrated. Up to 130 mJ output energy at 2.1 μ m has been generated, operating at 5 Hz repetition rate with a pulse duration of 73.7 ns. The average beam quality factor of M 2 is measured to be ∼ 3.5. This laser has a simple design and compact structure, which is very suitable for many applications. To the best of our knowledge, this is the highest output energy for LDs pumped single rod Tm:Ho:YAG laser.

A Ho:SSO crystal was employed as an efficient saturable absorber Q switch for the pulsed Ho:YAG laser for the first time. The characteristics of the passive Q-switch Ho:YAG laser were studied with different incident pump power and different laser energy density around the Ho:SSO. The single pulsed energy varied from 8.3 μJ to 76.6 μJ with the increasing of the incident power from 2.2 W to 8.2 W. The maximum repetition rate was 42.1 kHz, and the minimum pulsed duration was 48 ns. The maximum single-pulse peak power was 1.53 kW. The output center wavelength shifted from 2090.1 nm (the continuous-wave mode) to 2091.3 nm (the passive Q-switch mode).

In this work, we demonstrate the use of 2.12-μm Ho:YAG laser with a deviated-firing fiber for laser ablation on chicken tissues. The tissue ablation tests were conducted under non-contact and contact conditions. The thermal damage and ablation efficiency made by the fiber on the tissue were quantitatively analyzed and compared. It is found that, the ablation threshold is lower and ablation is more efficient under the non-contact mode, in which the fiber device is kept at a small distance of 0.5–1.0 mm from the target tissue. This can be attributed to amber space between the fiber and the tissue that allows the ejection of ablation debris and vapor from the ablation zone. This ensures better transmission of laser energy from the fiber device to the target tissue. Such design offers better ablation efficient and enhances the service life of the medical fiber device.

Zusammenfassung Fragestellung: Meningeome und Neurinome stellen gutartige Tumore dar. Ihre derb-fibrosen oder verkalkten Anteile und die enge tumorose nachbarschaftliche Beziehung zu neurovaskularen Strukturen fordem eine schonende Operationsweise, die durch herkommliche Instrumentarien nicht verwirklicht werden kann. Ziel fiir die Mikroneurochirurgie ist es, ein ablativ wirkendes Instrumentarium zur Beseitigung spinaler, cerebraler Raumforderungen ohne mechanische Irritation und ohne thermische Begleitschadigung verfagbar zu haben. Methode: Aus diesem Grund wurde der Ho:YAG-Laser in einer tierexperimentellen und klinischen Studie eingesetzt.

This article discusses the evolution of laser-assisted disc decompression, foramenal laser endoscopic disc ablation and endoscopic foramenotomy using a Holmium:YAG laser. Advantages of using this wavelength and several techniques for its use in minimally invasive approach to the lumbar spine are reviewed. The article also discusses the current devices and delivery systems available for this application.

Objective To evaluate the effectiveness of cystoscopic lithotripsy, we performed Amplatz sheath technique using Ho: YAG laser. Maheshwari first reported the use of an Amplatz sheath in the female urethra in 1998, and Okeke et al reported the use of an Amplatz sheath for male patients during cystolithotripsy in 2004. The usefulness of the holmium (Ho): yttrium aluminum garnet (YAG) laser lithotripsy is widely accepted, even for large bladder calculi. Since then, there have been no more reports of using the sheath with an Ho: YAG laser. Technical Considerations We inserted the Amplatz sheath conversely. Because of the clear visualization, we used higher laser settings with 2.5 J × 15 to 20 Hz. Results We experienced 3 female patients that were successfully treated with the Amplatz sheath technique using Ho: YAG laser lithotripsy. In these 3 patients, whose stone burdens were 4.5, 3.8, and 4.3 cm, they were able to successfully become stone-free with surgeries of 74 minutes, 67 minutes, and 58 minutes, respectively, with no complications. Conclusion We experienced 3 female patients that were successfully treated with the Amplatz sheath technique using Ho: YAG laser lithotripsy.

Objective To assess and evaluate the intraoperative power settings during clinical laser lithotripsy using the Ho:YAG laser in respect to calculus formation, size and position. Material and methods In total 145 operations for 99 solitary and 46 multiple kidney and ureter stones were retrospectivly analyzed. Laser fibers with core diameters of 220, 365 and 600 μm were used. Results Mean stone size was 10 mm2, mean operation time was 90 min, mean laser-related fragmentation time (lrft) was 365 s. There was a correlation between stone position throughout the collecting system, the overall operating time, the laser-related fragmentation time and the applied laser power (mJ). Overall applied laser power did also correlate with the predominant calculus composition. Conclusion In Ho:YAG laser treatment of urinary calculi, operation- and laser-related fragmentation times are directly related to stone size, composition and position.