A NEW EFFECT-BASED CLASSIFICATION OF LASER APPLICATIONS IN SURGERY AND MEDICINE (1996)

In the last decade the applications of the laser in surgery and medicine have increased dramatically. With the increase of indications has come a concomitant increase in possible classification of laser reactions. The author presents a classification which is based on the laser/tissue reaction rather than on the hardware used to produce the laser beam. Laser/tissue reactions fall into two broad groups. When the tissue reaction to absorption of the incident laser energy results in photodestruction of, or an irreversible photomodulated change to the tissue architecture, then the level of reaction is higher than the survival threshold of the target cells. The author refers to this as high reactive-level laser treatment (HLLT), or more generally as laser surgery. On the other hand, the level of tissue reactivity to very low incident power and energy densities is well below the cells' survival threshold so that instead of being damaged the cells are directly activated by the low incident photon density. In this case the changes in the irradiated tissue are photoactivative and reversible: the author refers to this group of reactions as low reactive-level laser therapy (LLLT), or more generally as laser therapy. Both of these groups can be classed under the general heading of laser treatment (LT). LT is further subdivided into three main types: mono-type LT (Mo-LT, single laser treatment; multi-type LT (Mu-LT, multi-laser treatment); and concomitant LT (Cc-LT), in which any of the above LT types can be used in combination with conventional treatment methods. Mo-LT in turn contains pure LT (Pu-LT) single laser, single reaction; and auto-simultaneous LT (ASi-LT), single laser with a range of reaction types, each of which has its own abbreviation. Mu-LT contains two main sub-types, combined LT (Cb-LT) and compound LT (Cp-LT). Cb-LT concerns the same disease whereas Cp-LT is used to describe 2 or more diseases treated with the same or different lasers. Both Cb-LT and Cp-LT are further subclassified into the homogeneous and xenogeneous types, referring to the use of the same or different types of laser, respectively. If the lasers are applied at the same time, that is homo- or xeno-simultaneous laser treatment (HoSi-LT, XoSi-LT), and if at different times the term is homo- or xeno-succesive laser treatment (HoSu-LT, XeSu-LT). The various sub-sets of Mono-type and Multi-type laser treatment are further expanded, to give an accurate, treatment-based categorization of laser treatment. In addition to the above classification, the author has devised a graphical representation of laser surgical and therapeutic beams whereby the laser type, parameters, penetration depth, and tissue reaction can all be shown in a single illustration, which the author has termed the ‘Laser Apple’, due to the typical pattern generated when a laser beam is incident on tissue. Apple types fall into two main subdivisions, destructive or D-Apples (HLLT) which include the C-Apple (carbonization), V-Apple (vaporization) and so on, and the activative or A-Apple type (LLLT). When the above classification is combined and illustrated with the appropriate laser apple type or types, the author feels this offers an accurate and simple method of classifying laser/tissue reactions by the reaction, rather than by the laser used to produce the reaction.