Computer-guided laser probe for ablation of brain tumours with ultrashort laser pulses

A computer-guided laser probe has been developed for the application of ultrashort-pulsed lasers in neurosurgery. It is part of a novel operation concept for the treatment of deep-seated brain tumours. The system combines the positioning accuracy of stereotactic or neuronavigated instruments with the 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 guide the embedded optics, the laser radiation is focused at any time onto the current tissue surface. Since every single laser pulse has only a small effective volume of about 8 x 10(5) microm3, the application of a large number of succeeding pulses can be adapted to required geometries. Tissue fragments are removed from the growing operation cavity by continuous irrigation and suction through the laser probe. Blood vessels are detected by a confocal 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 well as its use in ablation and coagulation experiments are presented. A description of the overall operation system is given.