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6th ESACP Congress, Heidelberg, April 7-11, 1999 |
A151
INTRODUCTION: Although there is an increasing popularity of lasers in
orthopaedic surgery there is a growing concern about negative side effects
of this therapy e.g. prolonged restitution time, radiation damage to adjacent
cartilage or depth effects like bone necroses. Despite case reports and
experimental investigations in the last few years little is known about
the extent of acute cartilage damage induced by different lasers types and
energies. Histological examination offers only limited insights in cell
viability and metabolism. Ho:YAG and Er:YAG lasers emitting at 2.12 and 2.94
µm, respectively, are ideally suited for tissue treatment because these
wavelengths are strongly absorbed in water (claim to lower the risk of
iatrogenic cartilage damage). The purpose of the present study is to
evaluate the effect of laser type and energy on chondrocyte vitality in
an ex vivo model. Free running Er:YAG (E=100/150 mJ) and Ho:YAG
(E=500/800 mJ) lasers were used at a fixed pulse length of 400 µs.
RESULTS AND CONCLUSIONS: Although the energy is lower, cartilage
ablation was 3 times higher with Er:YAG laser than with Ho:Lasers.
Thermal damage - as assessed with the life and death cell viability
test - was much higher with Ho:YAG than with Er:YAG lasers. The extent
of thermal injury was as deep as 1800 µm with Ho:YAG and 70 µm with
Er:YAG. Confocal microscopy is a powerful tool for assessing changes
in tissue structure after laser treatment. In addition this technique
allows us to quantify these alterations in a temporal and spatial resolution
without using animal experiments.
PRESENTATION OF AN NEW EX VIVO MODEL USING CONFOCAL MICROSCOPY TO ASSESS
LASER INDUCED CARTILAGE INJURIES
Weiler Ch 1 3 4, Frenz M 2, Schaffner T 1, Mainil-Varlet P 1
1) Inst.Pathology, University Bern,
2) Inst.Applied Physics, University Bern,
3) Hôpital Cantonal de Fribourg, Orthopedic Dept, Switzerland,
4) Inst.Pathology, LMU-University Munich, Germany