Photo: Doctor Martin Wehner
Doctor Martin Wehner; © privat

Doctor Martin Wehner works at the Fraunhofer Institute for Laser Technology ILT in the Biotechnology and Laser Therapy division. talked to him about medical laser, what it already accomplishes today and whether the future has already begun. Mr. Wehner, the area of medical technology cannot be imagined anymore without the laser. Medical plastic products and implants are manufactured with lasers and surgeries are performed with them. Could we actually get by today without laser technology?

Martin Wehner: You could certainly still get by without it – but you would not want to in the case of eye diseases for refraction power corrections for example. Especially in these cases, the laser-supported removal of the eye cornea is currently the only procedure which makes the most sense. For other applications for the eyes, like for the treatment for retinal detachment therapy all the way to macula regeneration, the laser is also the instrument of choice. Yet the laser in terms of all the surgical areas indeed still remains an option. Could you give us an example where laser is still used in the beginning stages?

Wehner: One topic, which has been researched in the past few years, but has not been satisfying for treatment, is hard fabric removal through laser radiation. This means for example the removal of tooth material, cavity removal as well as bone surgery. Even though there are some procedures to accomplish this with lasers: Thus far the laser was not able to play up its advantages to its fullest in this area. Either the speed of operation of the material was too slow or the necessary equipment on the whole, meaning the laser source and laser conduct, was relatively elaborate compared to mechanical instruments. For this reason, thus far the laser has not had an easy entrance into the operating room. There are new developments however, which are on a great path to change all this. For example ultra short pulsing lasers with high overall performance, which allows high material removal ratios without triggering a thermal effect or influence the material of the respective fabric. What still needs to be resolved however is the improvement of beam guidance of these ultra short pulsing systems – because you have to get from the currently very stiff hinged brackets to flexible, fiber-guided transmission of laser radiation. Another important subject for several research groups is the surface functionalization by means of laser radiation: What are we meant to imagine here?

Wehner: With the aid of the laser, you can create surface structures by removing material, and so for example create porosity. This procedure is mostly applied with implants, which are intended to grow together with the bone. However, these surface areas also influence the cell growth of tissue. This is why there are continuative research studies, to structure surface areas in a way that they can be populated as well as possible by cells. Another method in this area is the application of material, which is especially compatible, via laser. A lot is happening right now in these diverse application areas. This research is particularly interesting in Tissue Engineering, a procedure for re-growing body tissue in the laboratory, to make tissue-or organ replacement possible. Especially in this area, laser technology proves itself invaluable, as specific geometrical structures for the backing framework of the tissue are being created.

Photo: Barcode
Even when we go shopping, lasertechnology is present;
© djayo/SXC Laser in medical science is mostly known for vaporization of tissue. It is also supposed to be able to conglutinate tissue. Is this already a reality?

Wehner: It could soon become a reality. For many years there have already been operations in terms of tissue bonding, which means the heating treatment of tissue, so that proteins denature and through this, similar to an adhesive, harden. Thus far though, results have not been so great, since it was very difficult in this application to address the different environmental conditions. Each situation and each tissue is very different. As a result, laser radiation parameters have to be adjusted to the respective conditions, but the processing window – this meaning the area in which the laser radiation is effective, but has not caused thermal damage to the tissue yet – is very small. And so it’s difficult to hit the processing window in practice. This is also a research point we are working on right now. For these laser procedures, temperature measuring devices or optical measuring equipment to determine the morphology of tissue are needed to gather more data on the entire process and build up a control. Only then will it be possible to work with a laser beam similarly to other surgery tools, without too many unknowns playing a role. Recently, the laser celebrated its 50th birthday. What else can we expect over the next few years from laser technology?

Wehner: There will be increased applications for laser in the medical area, especially in endoscopic and minimally invasive procedures. The laser has the advantage of being able to be guided through thin optical fibers, just like the monitoring systems with which surgeons follow on what is happening in the body. If now we also succeed in improving the medical standard processes – like for example thermal coagulation, i.e. stanching blood in the body and shearing of tissue – to the point where a safe handling of the laser by a surgeon becomes possible, we will certainly break new grounds in this area.

This interview was conducted by Simone Ernst and translated by Elena O'Meara.