Proposal of a computerized algorithm for continuous wave CO2 laser on-line control during orthopaedic surgery

Abstract

This paper is the continuation of the Phase I report published in 1992 by Canestri. It contains recent findings on how to speed-up the process of sublimated volume forecasting for a TEM11* CO2 laserbeam in CW mode following an original model proposed by the author--called LCA--here presented in a simplified version (LCA-s) on PMMA (polymethylmethacrilate) samples. Other interesting parameters, such as the time required to create the minimal injury vb along with its physical interpretations, are reported and explained. TEM11*, TEM01* and TEM00 beams profiles are also compared and discussed for LCA-s. The results of both Phase I and Phase II of this investigation can be integrated in one single solution package for the end-user, combining fast decisions making and operational features. The final part of this paper describes the 'helmet-mounted' data recall visor methodology which allows the surgeon to access to a data base for information retrieval during the course of an operation without interrupting the surgical case itself. This particularly interesting application allows the surgeon to consult a centrally-located data base which contains important information regarding similar clinical cases, choice of laserbeam profiles and focal lengths, simulation of beam behaviours, performances and other data. The on-line and direct access to the data base supports him in all those borderline situations in the O.R. in which the laser device type and configuration/calibration play a device role in the success of the operation. Also, the helmet-mounted display frees surgeon's hands in order to allow him to continue the operation while consulting the data base on-line, thus speeding up decision processes regarding changes of laser set-up, general calibration optimization and remote clinical consultancy.

"Analysis of the Evaporation to Sublimation Phase Transition during Minimal Invasive Surgery Procedures via Pulsed CO2 lasers"

“…In 1992, the Author has demonstrated [8] the existence of a very simple empirical law which allows to forecast the volume ablated by a CO2-TEM22 laser beam (…”

“…is the resulting crater volume, f k is the focal length in use, f b is the basic focal length, F Sb is the Focal Sequence of both fk and f b , while te is the exposure time and v b (f b ) is the basic ablated volume of F Sb just after melting and prior to evaporation [9]. The following definitions have been introduced:…”