Reduction of thermocoagulative injury via use of a picosecond infrared laser (PIRL) in laryngeal tissues

Abstract

The carbon dioxide (CO2) laser is routinely used in glottic microsurgery for the treatment of benign and malignant disease, despite significant collateral thermal damage secondary to photothermal vaporization without thermal confinement. Subsequent tissue response to thermal injury involves excess collagen deposition resulting in scarring and functional impairment. To minimize collateral thermal injury, short-pulse laser systems such as the microsecond pulsed erbium:yttrium-aluminium-garnet (Er:YAG) laser and picosecond infrared laser (PIRL) have been developed. This study compares incisions made in ex vivo human laryngeal tissues by CO2 and Er:YAG lasers versus PIRL using light microscopy, environmental scanning electron microscopy (ESEM), and infrared thermography (IRT). In comparison to the CO2 and Er:YAG lasers, PIRL incisions showed significantly decreased mean epithelial (59.70 µm) and subepithelial (22.15 µm) damage zones (p < 0.05). Cutting gaps were significantly narrower for PIRL (133.70 µm) compared to Er:YAG and CO2 lasers (p < 0.05), which were more than 5 times larger. ESEM revealed intact collagen fibers along PIRL cutting edges without obvious carbonization, in comparison to diffuse carbonization and tissue melting seen for CO2 and Er:YAG laser incisions. IRT demonstrated median temperature rise of 4.1 K in PIRL vocal fold incisions, significantly less than for Er:YAG laser cuts (171.85 K; p < 0.001). This study has shown increased cutting precision and reduced lateral thermal damage zones for PIRL ablation in comparison to conventional CO2 and Er:YAG lasers in human glottis and supraglottic tissues.

Comparative study of wound healing in rat skin following incision with a novel picosecond infrared laser (PIRL) and different surgical modalities

“…Ex vivo soft tissue incisions made with PIRL have demonstrated nearly complete absence of thermal injury and much narrower cutting gaps when compared to CO 2 laser and scalpel . Infrared thermography has shown minimal ex vivo skin, mucosa, bone, and cartilage temperature rise during ablation using PIRL in contrast to Er:YAG‐Laser . Further, the detection of protein activity and intact higher order protein structure in the ablation‐aerosol emphasizes the soft character of the DIVE‐ablation process .…”

Homogenization of tissues via picosecond-infrared laser (PIRL) ablation: Giving a closer view on the in-vivo composition of protein species as compared to mechanical homogenization

“…The soft ablation of tissue by PIRL is achieved under the conditions of desorption by impulsive excitation (DIVE) [21] in which the water molecules contained within the tissue are transferred into the gas phase in an ultrafast, explosive manner. DIVE results in intact cellular biomolecules blasting out of the sample with minimized heating or shock wave damage imposed on the tissue and biomolecules [22] , [23] , [24] , [25] . Kwiatkowski et al showed that the tissue proteome is present in the condensate of the DIVE-induced tissue aerosol.…”

Mass Spectrometry-Based Intraoperative Tumor Diagnostics

“…The energy absorbed by the tissue-own water molecules is completely converted into translational degrees of freedom rather than being lost to surrounding tissue through thermal or acoustic transport. This process called ‘desorption by impulsive vibrational excitation’ [96] drives the water molecules into the gas phase without thermal or shock-wave damage to the ambient tissue, resulting in cold tissue vaporization [97]. The unique properties of PIRL enable precise and accurate ablation with minimal cellular damages to the surrounding tissue, significantly reducing scar formation compared with millisecond infrared lasers commonly used in medical laser surgery [97–104].…”

“…This process called ‘desorption by impulsive vibrational excitation’ [96] drives the water molecules into the gas phase without thermal or shock-wave damage to the ambient tissue, resulting in cold tissue vaporization [97]. The unique properties of PIRL enable precise and accurate ablation with minimal cellular damages to the surrounding tissue, significantly reducing scar formation compared with millisecond infrared lasers commonly used in medical laser surgery [97–104]. Next to the medical application, the group of Hartmut Schlüter showed that PIRL ablation released proteins intact from tissues without changing their exact chemical composition and that posttranslational modifications and enzyme activities of the PIRL-ablated proteins remained unaltered [96].…”