Ablation of neural tissue by short-pulsed lasers ? a technical report

Abstract

The basis for most laser applications in neurosurgery is the conversion of laser light into heat when the incident laser beam is absorbed by the tissue. Irradiation of neural tissue with laser light therefore leads to its thermal damage. However, due to the diffusion of heat energy into the surrounding tissue, often there is thermal damage to neural tissue outside the area of the target volume. These are the characteristics of thermal laser/tissue interaction. In this paper we discuss how we used three different short-pulsed lasers to achieve non-thermal ablation of neural tissue. Three different short-pulsed lasers were used to generate ultrashort laser pulses in the picosecond to femtosecond range. The interaction of such laser pulses with tissue was predicted to be nonthermal. The short-pulsed lasers were used for the ablation of neural tissue using an in vitro calf brain model. The histopathological examination of the lesions revealed that the neural tissue had been removed very precisely without any sign of thermal damage to the surrounding tissue.

Beneficial Use of a New Hand-Held CO2 Laser Fiber in Resection of a Calcified and Vascular Intraventricular Tumor

“…The authors hypothesized that laser-tissue interactions are primarily mechanical in this context because ultrashort laser pulses allow little time for the conduction of heat to surrounding tissue (49). The experiment by Suhm et al (49) assessed several different light energies but did not evaluate CO 2 lasers specifically. However, in an earlier study by Jain (27), pulsed CO 2 laser energy used to make an incision in a rat brain was shown to cause less damage to surrounding tissue than an equal amount of energy applied in continuous wave mode.…”

“…CO 2 laser energy is superiorly absorbed by neural tissue and minimizes thermal diffusion and resulting collateral damage. However, some evidence suggests that short-pulsed bursts of laser energy could reduce thermal diffusion further, potentially improving the overall precision of the CO 2 laser (27,49). Using an in vitro calf brain model, Suhm et al (49) showed that ultrashort laser pulses, in the picosecond to femtosecond range, can ablate neural tissue without producing a significant thermal lesion.…”

“…However, some evidence suggests that short-pulsed bursts of laser energy could reduce thermal diffusion further, potentially improving the overall precision of the CO 2 laser (27,49). Using an in vitro calf brain model, Suhm et al (49) showed that ultrashort laser pulses, in the picosecond to femtosecond range, can ablate neural tissue without producing a significant thermal lesion. The authors hypothesized that laser-tissue interactions are primarily mechanical in this context because ultrashort laser pulses allow little time for the conduction of heat to surrounding tissue (49).…”

“…Using an in vitro calf brain model, Suhm et al (49) showed that ultrashort laser pulses, in the picosecond to femtosecond range, can ablate neural tissue without producing a significant thermal lesion. The authors hypothesized that laser-tissue interactions are primarily mechanical in this context because ultrashort laser pulses allow little time for the conduction of heat to surrounding tissue (49). The experiment by Suhm et al (49) assessed several different light energies but did not evaluate CO 2 lasers specifically.…”

An in vitro study of femtosecond laser photodisruption in rabbit sclera

“…As a consequence, the secondary thermal and mechanical effects should be reduced dramatically with fs-photodisruption. Targeted high precision photodisruption, which has been demonstrated in this paper, predicts minimally invasive surgery inside cells [12], tissues [13,14] or even a whole organ of the human body such as the eye [15,16] and tooth [17,18].…”