The scalpel is considered the classic surgical instrument and as such, has remained unchanged for quite some time. However, today’s technology opens up a world of new possibilities for cutting tissue. Next to high-frequency electrosurgical scalpels that work with electric power, surgeons also use a variety of different lasers. They promise great usability and better treatment.
Medical science has used lasers since the 1960s, just a few short years after the first gas lasers had been developed. The arrival of other types of lasers, such as dye lasers or solid-state lasers has drastically broadened their applications in medicine. Laser light is produced in different wavelengths using different laser media. These have different effects on human tissue, which determines their specific application in the surgical field. In an interview with MEDICA-tradefair.com, Dr. Wolfgang Neuberger, CEO of biolitec AG, uses two different types of lasers as an example and explains the distinction between them: "CO2 lasers are great for cutting but bad for coagulation. Meanwhile, Nd: YAG lasers penetrate deeply into the tissue, coagulate wonderfully but they are not great for cutting. And if they are used for cutting, they cause major tissue damage."
CO2 lasers generate light with a wavelength of 10,600 nanometers and next to cutting applications, they are also used in dermatology. Meanwhile, the light of Nd: YAG lasers features a wavelength of 1,064 nanometers and is used in ophthalmology applications in addition to coagulation. Other surgical applications with the corresponding wavelengths, respective irradiation intensities, and exposure durations, include the endoscopic removal of kidney stones, dental treatments, and ENT applications as well as cancer surgery, for example.
Laser surgery: advantages and limitations
Compared to other, purely mechanical instruments, lasers offer several advantages for surgeons. When you cut with a scalpel, compressive and tensile forces impact the tissue, which can decrease the accuracy of the cut. This is not the case with lasers, which are contactless. The coagulation of the cut made by a laser is an advantage in many surgeries. On the one hand, it prevents loss of blood in the patient, while it also avoids that the surgeon loses visibility at the surgical site due to bleeding. Many procedures that require the highest precision would be impossible without the use of a surgical laser or could only be performed with much greater effort and result in a poorer outcome. Examples of this in the field of ophthalmology include retinal detachment or LASIK surgeries. Having said that, contactless surgery is also a drawback since surgeons are no longer able to feel the tissue at the surgical site, preventing them from gleaning information about the location of blood vessels for example.
Surgical lasers can also be used to perform minimally invasive procedures. In this instance, laser light is conducted through optical fibers of an endoscope to the surgical site, which makes surgery on internal organs and even inside blood vessels possible. In this case, surgeons can remove deposits, open up blocked blood vessels or treat varicose veins. However, endoscopic surgery is not possible with all wavelengths: CO2 laser light cannot be conducted this way, which is why it is so far only suitable for open surgery approaches.
That being said, surgical lasers do not just make patient treatment easier. Compared to scalpels, they are very complex devices, whose application depends on various prerequisites as well as the infrastructure of the medical office and the operating room: in addition to a power supply, some devices also require water for cooling or are only functional in air-conditioned rooms at a specific temperature and humidity level. What's more, many lasers are bulky and heavy, making it impossible to move them between operating rooms. Last but not least, they also imply the technical knowledge of surgeons and surgical staff to operate the systems and involve high acquisition costs.
Compact and high-performance devices are able to change this. One example for this is the "Leonardo" product line by biolitec AG: "Leonardo comes in different power levels and sizes. Our smallest model roughly weighs 900 grams and is barely larger than a smartphone. Along with its application in medical offices, it also facilitates mobile use," says Wolfgang Neuberger in our interview.
Depending on the wavelength of the laser light, it impacts the tissue differently. That's also why physicians previously had to use different devices for different applications. "Leonardo" is different. "The first important aspect for us was to ensure that physicians can cover a large variety of applications within their specialty like ENT, for example, with one single device, and to eliminate the need to use two or three different devices at the same time," Neuberger explains. "By combining two wavelengths – 1,470 and 980 nanometers – in one device, we have the option of changing the effect on the tissue by individually selecting the output of each wavelength." By using this combination tool, surgeons are flexible in switching between cutting and coagulation, which drastically increases usability.
Modern surgical lasers: improved usability, increased treatment quality
One example of how lasers increase the treatment quality are femtosecond lasers. They do not generate a continuous laser pulse but rather individual pulses that last one femtosecond (one quadrillionth of a second). Femtosecond lasers are part of the so-called pulsed laser family. Unlike the so-called continuous-wave lasers, they have one major advantage: thanks to the individual pulses, less energy is generated in the tissue than is the case with a continuous beam, which in turn causes less damage to the tissue. With the femtosecond laser, the cutting effect occurs by destroying the molecular bonds in the tissue. This effect is limited to a few micrometers and happens in picoseconds (one trillionth of a second). This prohibits any interaction with the surrounding tissue, which is why these types of lasers produce more precise cuts than continuous-wave lasers.
This technology is primarily utilized in the field of ophthalmology. Prof. Frederik Raiskup of the Carl Gustav Carus University Hospital in Dresden has recently started to use the "FEMTO LDV Z8" femtosecond laser from the Ziehmer Company for refractive and cataract surgery. "Since we have started to use the system in March, we have not had any problems or intraoperative complications of those any procedures we have performed. I am also very pleased with the precision of cuts and the repeatability between patients," he explains in an interview with MEDICA-tradefair.com. The "Z8" laser is also a compact, mobile and easy to use device. In addition, the femtosecond laser also broadens the spectrum of possible treatments for various clinical pictures and facilitates better treatment results with a low-risk procedure.
In the surgical field, modern lasers embody usability and flexibility in the eyes of surgeons. For patients, they signify prevention, better treatment results and subsequently also improve their quality of life after a surgical procedure.
Another aspect of laser applications in medicine is photodynamic therapies. In this case, active substances are administered to treat tumors or skin diseases. These substances generate a local therapeutic effect thanks to subsequent low-intensity laser irradiation. These methods are gentler than radiation, chemotherapy or surgery for example. Find out more about the application and possibilities of photodynamic therapy in our video, using the example of bile duct cancer:
Video: Photochemical internalization – A new hope against bile duct cancer?
Advanced bile duct tumors cannot always be removed surgically. Then, patients receive chemotherapy and a stent that corrects the narrowing of the bile duct that is caused by the tumor. Another, local therapy option is tested at the University Hospital Frankfurt: laser light is used to transport drugs into the tumor during photochemical internalization.