Ultra-conservative minimally invasive surgery (UCMIS) with pulsed non-Gaussian CO(2) laser beams focused through the shortest possible focal length.

Objective: This article describes a mathematical approach to identifying the absolute shortest laser optical focusing head f(min) associated with the smallest not-to-exceed ablative crater radius and depth to be used during ultra-conservative minimally invasive surgery (UCMIS) procedures with pulsed CO(2) lasers. This value is important because it allows forecasting the micro-boundary ablative conditions of a laser device implemented in the operating room (OR) in conjunction with minimally invasive tools. The primary goals of reducing the invasive character of an operation, and the associated risks of unwanted lateral tissue damage during surgery, are the key objectives of MIS protocols.

Accurate quantification of the optical absorption coefficient and of the thermal relaxation time for PMMA and for low-water-content media during early ablation with CO2 laser beam at the wavelength of 10.6 μm.

Objective: This article describes a new mathematical approach for a more accurate identification of the optical absorption α (per centimeter) and the thermal relaxation time τr (seconds) of dry poly(methyl-methacrylate; PMMA) at λ = 10.6 μm.

Background: The data available in the literature do not accurately describe the numeric value of α (per centimeter) for PMMA and other biologic media.

Computerized thermal characterization tool (CT)2 for complete thermodynamic coefficients mapping at the wavelength of 10.6 microm: a PMMA case report.

Objective: This paper details a proposed clinical identification tool, the Computerized Thermal Characterization Tool or (CT)(2), designed to precisely quantify and forecast the ablation capabilities of a CO(2) laser beam and to optimize its usage when human tissue is exposed to 10.6 microm wavelength radiation.

Background: As seen in other studies by the same author, the correct identification of the optical absorption of polymethylmethacrylate (PMMA) allows isolating other key time-dependent coefficients, all described qualitatively rather than quantitatively in the literature, with better accuracy.

Optical absorption coefficient, time of thermal relaxation, time of surface threshold, and time of heat incubation for PMMA samples at the CO2 laser-beam wavelength of 10.6 microm.

Objective: This paper discusses in detail the mathematical identification of the optical absorption alpha (cm(1)) of Beer's law, a crucial parameter to study the development of laser beam craters into dry poly(methyl methacrylate) (PMMA) samples exposed to steady CO(2) laser beams emitting radiation at lambda = 10.6 microm in continuous- wave (CW) mode. Three additional time-dependent coefficients have been determined as well.

Sudden and unpredictable below-surface ablation pattern changes by CO2 laser beams: a qualitative description of five macroscopic cases observed in PMMA with high probability to occur during surgery in low-water-content tissues.

Objective: This paper describes five cases of macroscopic irregular CO(2) laser-beam ablation patterns that can generate below-surface complications during surgery. These five cases are related to curved reflected beams, curved craters generation with abnormal superficial thermal damage, and craters that show irregular wall contours. Although these alterations have been observed during irradiation in PMMA samples (polymethilmethacrylate), it is possible that similar unpredictable changes also happen in low-water-content, hard and uniform biological tissues such as compact bone, enamel, and dentin.