The True Ablation Effect of Holmium YAG Laser on Soft Tissue

Abstract

The overall mean ID was significantly higher than the theoretical 0.4 mm PD described for Ho:YAG laser. The energy, frequency, and pulse length had individual effects regarding ID, incision width, and coagulation. The ID should be specified in accordance with the laser's power output and should not be confused with the physics of PD concept.

Thulium fiber laser: the new player for kidney stone treatment? A comparison with Holmium:YAG laser

“…The Holmium:YAG laser operates at 2120 nm and is highly absorbed in liquid water, leading to a rapid formation of a vapor bubble after emission in pulsed mode [ 25 ]. This interaction with water also adds to the safety profile of Holmium:YAG lasers, as the optical penetration depth is limited to 400 µm and coagulation of tissue beyond this distance only occurs in the high pulse energy range [ 7 , 26 ]. Evidence of stone composition phase changes supports a photothermal interaction of Holmium:YAG laser with the stone matrix [ 4 , 27 , 28 ].…”

“…(3) favorable safety profile with minimal tissue penetration depth and low risk of undesirable tissue damage due to the relatively high absorption coefficient of the Holmium:YAG laser wavelength in water [7]; (4) versatility which allows a Holmium:YAG laser system to be used for soft tissue applications additionally to stones, which partially offsets the costs of high-power systems [8,9].…”

“…After having been evaluated as an innovative tool for tissue ablation with favorable hemostatic characteristics, the Holmium:YAG laser was eventually applied to urinary stones for lithotripsy [ 2 ]. Compared to other lithotripsy techniques, the Holmium:YAG laser presents several important advantages: (1) suitability for fragmentation of all known urinary stone types into small stone particles [ 3 , 4 ]; (2) ability to operate with thin and flexible delivery fibers with limited energy losses and with core diameters as small as 200 µm [ 5 , 6 ]; (3) favorable safety profile with minimal tissue penetration depth and low risk of undesirable tissue damage due to the relatively high absorption coefficient of the Holmium:YAG laser wavelength in water [ 7 ]; (4) versatility which allows a Holmium:YAG laser system to be used for soft tissue applications additionally to stones, which partially offsets the costs of high-power systems [ 8 , 9 ].…”

Analysis of Hemostasis Procedures through Machine Learning of Endoscopic Images towards Automatic Surgery

“…In a previous study, we proposed and developed a system that can automatically detect the organ, bleeding, and hemostasis regions in real time to assist hemostatic procedures. (9) Hemostases are frequently performed in surgical procedures (10,11) such as tumor ablation and tissue dissection; therefore, robot assistance or automation can considerably reduce the burden on the surgeons. In addition, hemostasis induces the thermal degeneration of organs using energy devices.…”

Authors Reply Re: Maheshwari PN, Arora AM, Sane MS, Jadhao VG. Safety, feasibility, and quality of holmium laser en bloc resection of nonmuscle invasive bladder tumors: A single-center experience. Indian J Urol 2020;36:106-11

“…In contrast to the thermal damage caused by monopolar and bipolar conventional bladder tumor resection, the thermal damage by holmium laser is expected to be negligible as the coagulation thickness achieved by the holmium laser is only about 0.48 mm. [ 4 ] Regardless, the technique of en-bloc resection involves marking a circumferential resection margin 2–4 mm around the tumor and then lifting the entire tumor in one piece by working in the plane of the detrusor muscle. Thus, during en bloc resection, the energy source, whether monopolar, bipolar, or any kind of laser, would never come in direct contact with the actual tumor, avoiding any thermal damage.…”