Biocompatible coatings For the benefits of patients
People in blue surgical gowns hurry around, their faces half covered by masks. There are hoses and cables in a variety of colors everywhere. Sterilized stainless steel scalpels, tweezers, bone drills, clamps and other surgical instruments are neatly lined up on a cloth at the ready. Nothing is left to chance.
A good deal is expected of these medical instruments during an operation. As Canet Acikgoz, Segment Manager Medical at Oerlikon Balzers, explains, surface technology plays a decisive role here. With this in mind, greater emphasis is being placed on the functional coatings that are applied to scalpels, needle drivers, bone saws and reamers. “With physical vapor deposition (PVD), materials such as stainless steel and titanium can be coated with extremely hard and thin layers. The vacuum-based coating process can further improve the key properties of medical instruments,” she explains.
An important factor, for example, is friction, which can influence the performance of a bone drill: the less friction a drill like this generates, the lower the negative effect on surrounding bone will be. In the industrial sector, lubricants would be used in a case of this nature, but that is not possible in surgery. Consequently, Canet Acikgoz and her colleagues asked themselves: “What other possibilities for preventing friction are there besides the use of grease?” They came up with the idea of applying a friction-reducing coating to medical instruments. The technology is now being used successfully.
DLC coatings (Diamond-like-Carbon, which signifies very hard carbon coatings) with low coefficients of friction will provide lubricity, corrosion resistance, anti-sticking and antifouling. They even improve sharp edge retention of surgical instruments, which extends the service life of the instrument considerably. As an added benefit, cleaner cuts help surgical incisions heal more quickly and so reduce patient recovery time.
Corrosion resistance for extended lifetime
Canet Acikgoz, Segment-Manager Medical, Oerlikon Balzers
Coatings can also extend the life of these instruments, which are often expensive. For example, bone rongeurs must be able to withstand quite a bit. Blood and other bodily fluids contain numerous salts and proteins. After the operation, the bone rongeurs are subjected to sterilization to prepare them for their next use. Devices known as autoclaves are frequently employed for this purpose. In these chambers the instruments are sterilized by means of increased temperature, pressure and steam. However, salts, proteins and steam can corrode knives and make their blades dull. Special coatings help to better protect the base materials, such as stainless steel or titanium, from corrosion: “The aggressive substances are then unable to penetrate as easily, and they cause less damage as a result. Surgeons can rely on instruments over the course of a longer lifetime,” says Canet Acikgoz.
But physicians must also be assured that they will be able to see at all times – in the brightly lit surroundings of the operating room – the exact depth that the scalpel or drill has already penetrated. Light reflected from the instruments can cause an unpleasant glare or distraction. Stainless steel, for example, which is often used in medical environments, is highly reflective. Surface coatings can be used to darken medical instruments so that they reflect less light.
“Surgeons can rely on instruments over the course of a longer lifetime.”
Canet Acikgoz, Segment-Manager Medical, Oerlikon Balzers
Color coding enhances precision
As the coatings are available in different colors, instruments can also be colored differently. These color codes make it easier for the surgical staff to find the right instruments at any time and within seconds. The coating can also be applied as a marking on drills so that the surgeon is able to see how far into the bone the drill has already penetrated. All this helps these professionals to work quickly and with precision in the operating room.
Next step: antimicrobial coatings
Canet Acikgoz and her colleagues are currently working on another exciting topic: How can surface technology help with the dreaded threat of infections? In hospitals and other medical facilities, there is always a latent danger that germs may be introduced from outside and endanger patients. “We are working on antimicrobial coatings to help prevent infections in the operating room,” explains Acikgoz. Copper and silver, in particular, have the property of stemming the spread of bacteria. For example, surgical instruments made of titanium and other metals can be coated with silver to achieve this effect. But the coating alone is not enough, because in order to have an antimicrobial effect, the silver must first dissolve somewhat. Only then can the silver ions attack and eliminate the bacteria. “To start this process, we need a humid environment,” explains Canet Acikgoz. Bodily fluids can take over this function. Medical instruments coated with silver will not replace antibiotics in the fight against bacteria. However, the technology could allow doctors and hospitals to use fewer antibiotics during surgery.
Increased precision, improved durability, and entirely new features: Coating solutions from Oerlikon Balzers marketed under the brand name of BALIMED make a significant contribution to further improving medical instruments. These enable surgeons to work more efficiently and treat patients better and more safely at the same time. If things go as planned by Canet Acikgoz, her colleagues and Oerlikon Balzers, more precise scalpels and bone drills that can be used for longer periods of time are just the beginning.