A computer-guided laser probe has been developed for the application of ult
rashort-pulsed lasers in neurosurgery. It is parr of a novel operation conc
ept for the treatment of deep-seated brain rumours. The system combines the
positioning accuracy of stereotactic or neuronavigated instruments with th
e precise and therefore gentle characteristics of surgical lasers.
The probe has an outer diameter of 5.5 mm and is directly inserted into the
target volume. By a synchronized movement of three coaxial tubes, which gu
ide the embedded optics, the laser radiation is focused at any time onto th
e current tissue surface. Since every single laser pulse has only a small e
ffective volume of about 8 x 10(5) mu m(3), the application of a large numb
er of succeeding pulses can be adapted to required geometries. Tissue fragm
ents are removed from the growing operation cavity by continuous irrigation
and suction through the laser probe. Blood vessels are detected by a confo
cal laser-scanning microscope, which is integrated into the probe, and can
be closed by an additional coagulating laser.
In this paper, the design and technical properties of the laser probe as we
ll as its use in ablation and coagulation experiments are presented. A desc
ription of the overall operation system is given.