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

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

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

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

Ex vivo feasibility study of endoscopic intraductal laser ablation of the breast

Objective: To determine the feasibility and safety of breast endoscopic thulium laser ablation for treatment of intraductal neoplasia. Study Design: Ductoscopy is a minimally invasive endoscopic approach of the milk ducts of the breast via the nipple. Besides diagnosis in women with pathologic nipple discharge (PND), it allows non-invasive removal of intraductal lesions with a stalk like papillomas. Removal, however, is often incomplete and flat lesions cannot be targeted. We therefore developed laser ductoscopy. Methods: Dosimetry of laser ductoscopy was assessed in thirteen mastectomy specimens, applying power settings of 1–5 W with 100–1000 ms pulsed exposure to a 375-μm outer diameter thulium fiber laser. Subsequently histology was obtained from the breast tissue that was treated with the Thulium laser. Results: Endoscopic view was maintained during ductoscopic laser ablation at 1–3 W. Increasing power to 4–5 W caused impaired vision due to shrinkage of the main duct around the ductoscope tip. Histology revealed localized ablation of the duct wall. Conclusion: We show for the first time that laser ductoscopy is technically feasible. The Thulium laser enables a superficial intraductal ablation and is a useful tool for intraductal interventions. An in vivo prospective study is needed to further demonstrate its potential. Lasers Surg. Med. 50:137–142, 2018

Thulium laser-assisted endoscopic third ventriculostomy: Determining safe laser settings using in vitro model and 2 year follow-up results in 106 patients

Background and Objective: Endoscopic third ventriculostomy is used to treat hydrocephalus. Different laser wavelengths have been proposed for laser-assisted endoscopic third ventriculostomies over the last decades. The aim of this study was to evaluate Thulium laser endoscopic third ventriculostomy heat penetration in the surrounding environment of the floor of the third ventricle in an in vitro setting with visualization of thermal distribution. Subsequently 106 Thulium laser endoscopic third ventriculostomy procedures were retrospectively analyzed to demonstrate safety. Methods: The in vitro visualization was based on the color Schlieren method. The heat penetration was measured beneath a tissue phantom of the floor of the third ventricle with a fiber of 365 μm in diameter at different energy settings; 1.0W (956 J/cm2), 2.0W (1,912 J/cm2), 4.0W (3,824 J/cm2), and 7.0W (6,692 J/cm2), with a pulse duration of 1.0 second. All experiments were repeated five times. In addition, 106 Thulium laser endoscopic third ventriculostomy procedures between 2005 and 2015 were retrospectively analysed for etiology, sex, complications, and laser parameters. Results: In the energy settings from 1.0 to 4.0 W, heat penetration depth beneath the phantom of the third ventricle did not exceed 1.5 mm. The heat penetration depth at 7 W, exceeded 6 mm. The clinical overall success rate was 80% at the 2-year follow-up study. Complications occurred in 5% of the procedures. In none of the 106 investigated clinical patients bleeding or damage to the basilar artery was encountered due to Thulium laser ablation. Conclusions: The in vitro experiments show that under 4.0W the situation is considered safe, due to low penetration of heat, thus the chance of accidentally damaging critical structures like the basilar artery is very small. The clinical results show that the Thulium laser did not cause any bleeding of the basilar artery, and is a safe technique for laser endoscopic third ventriculostomy. Lasers Surg. Med. 50:629–635, 2018. © 2017 Wiley Periodicals, Inc