How does the Greenlight laser work?
Problems using Lasers in Surgery
Previously, the problem has been how to transmit the very high energy of the laser from the generator in the operating theatre into the prostate to produce this vaporisation effect. The Greenlight technology uses a very fine optic fibre which carries the light energy from the generator, through the operating telescope (cystoscope) to the prostate. This fibre is similar in appearance to the fibres used in fibre optic displays that used to be popular some years ago as ornaments. The light energy is internally reflected within the fibre and a tiny mirror at the end of the fibre directs the high-powered light source to its final destination in the prostate. One of the challenges has been to prevent the burning effect of the high temperatures produced affecting the operator using the equipment or the patient before it reaches the prostate. The optic fibre has been specifically manufactured for this task, but as a consequence, it is 'single use' due to the high energies been transmitted during surgery. If a patient has a very large prostate, it may require more than one fibre to complete the operation because of this.
The generator unit also uses a circulating water cooling system to keep the laser energy source at a low stable temperature to ensure efficient working of the unit as a whole. The previous Greenlight 80W system required an external high pressure water system to cool the unit, unlike the new generation HPS 120W system which has an internal water cooling system. This has made the HPS system a much more user-friendly unit enabling more patients to benefit from this procedure.