New near infrared fiber delivered laser sources for surgery: physical aspects and clinical implementation

Abstract

Thermal energy is commonly used for surgery to control bleeding of the surgical plane. Many sophisticated techniques are used for preventing and stopping blood loss during surgery. Electrosurgery is one of the most used and one of the most common instruments in the operating theatre. Electrical currents are generated in a high frequency, which does not interfere with nerve stimulation. Besides electrosurgery, also other devices are used to create thermal effects based on various other physical principles, such as Radio Frequent Ablation (RFA), Ultrasonic, High-intensity Focussed Ultrasound (HIFU), plasma coagulation, microwave, high pressure waterjet and electroporation. Also, laser is used as an energy device for surgical applications. Lasers are unique light sources by emitting a small parallel beam of intense monochromatic light. This enables a high intensity at a small surface area inducing high temperature by absorption of light at the surface. Surgical lasers in the near and mid infrared spectrum (1470nm and above) are of interest for soft tissue excisions due to the high energy absorption in water, thus preventing heat conduction into the depth of the tissue. However, these lasers have strong differences in laser tissue effect and should be carefully considered before using in clinical practice. Since 2005, the Thulium laser has been clinically introduced. It has the highest wavelength (2013nm) that can be delivered through optical fibers. The aim of this thesis is to evaluate the advantages and additional value of the Thulium laser compared to other existing energy devices. The infrared region is very interesting as it is a wide region (810nm-10.600nm) with many kinds of laser tissue interaction. The Thulium laser (2013nm) is a relatively new laser in this region and could safely replace the 810 and 1064nm lasers for laser assisted third ventriculostomy. It is no longer necessary to pre-carbonize the laser fibers of the 810nm and 1064nm laser as the Thulium laser has direct absorption of the light in soft tissue (water) with a reproducible effect. It has good potential for endoscopic surgery in general as the laser has the ability to deliver the laser light through low OH fibers with CO2 laserlike properties. It fits through nearly every working channel due to the small dimensions of the laser fiber. For intra oral surgery the Thulium laser has an advantage over electrosurgery, especially for tumor surgery of the tongue. The absence of muscle contractions by the use of laser compared to electrosurgery has several potential benefits such as better overview of the operating field and less bleeding due to minimal tissue manipulation. The small vasculature can be easily cut and coagulated by the Thulium laser. The novel handpiece which has been developed with integrated smoke evacuation can also contribute to optimal Thulium laser usage in oral surgery. To conclude, there are more clinical applications in which the Thulium laser could be used for. There is a bright future for the Thulium laser for various applications when more surgeons become aware and appreciate the special characteristics/features of this laser.