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Orchid Blog

Titanium Coating on PEEK Spine Implants

Posted: Wednesday, April 26, 2017

Orchid’s titanium coating on PEEK differentiates us in the market. The technology was developed at Orchid Switzerland (formerly Alhenia) and is sought after by our customers for spinal implants.

The spine, or vertebral column, is a bony structure formed from the vertebrae. It consists of 24 articulating and 9 fused vertebrae in the sacrum and the coccyx. All the vertebrae are separated with an intervertebral disc composed of cartilage. It plays a very important role as a shock absorber for the impact of the body’s daily activities, and keeps the two vertebrae separated

Nowadays, back pains are a real problem in the daily life. They could be work-induced or linked to advanced age, and the origins are various: spinal disc herniation, degenerative disc disease caused by aging, instability of the spine, etc.

In order to dampen back pain, spinal interbody fusion (arthrodesis) is a surgical technique widely practiced. The principle is to join two or more vertebrae by removing the intervertebral disc. In the case of a degenerative disc disease, a specific device, called cage or spacer, is necessary to maintain spine alignment and disc height. It is introduced in place of the intervertebral disc previously removed, and often used with supplemental posterior fixations.

Today, the fusion cages are principally made in titanium or in polyetheretherketone (PEEK). PEEK is known for its outstanding characteristics, such as high thermal stability, ease of processing, good biocompatibility and excellent mechanical properties. It is preferable to use PEEK instead of titanium for spinal implants for different reasons: PEEK has mechanical properties close to bone properties, it is lightweight compared to steel, aluminium and titanium, and it is transparent to X-Ray. Consequently, the surgeon can observe the bone integration and its development in the patient’s spine more easily.

One of the requirements for the effectiveness of fusion cages is the strong fixation with the host bone. Furthermore, the principal necessities for bone growth are systematically reviewed as follows: the material has to be a biocompatible material and the implant surface structure must be porous. Effectively, the porosity favours faster bone ingrowth as compared to a smooth surface and the bone must be under stress to develop itself. On the other hand, the roughness of the implant surface plays an important role for the long term adhesion. This integration of the bone (osteointegration) allows a good fixation of the implant.

Insofar as PEEK has a naturally hydrophobic surface (poor wettability) leading to a poor cell adhesion and thus no bone attachment. The search for a process that improves the uses of this material has led scientists and industrials to work with a variety of surface-modification technologies. A recent solution to improve the PEEK surface is still being developed: the coating of PEEK substrate with titanium powder. The difficulty with this solution is the poor adhesion of titanium onto PEEK substrates. This is a real challenge for the biomedical field, and there is a need to find an efficient process. Orchid Switzerland GmbH has developed the Heniapore-K™ titanium coating on PEEK using vacuum-plasma-spraying. This very porous coating fulfils the FDA requirement an is today the world reference in the spine industry.



HeniaPore-K™ Titanium coating onto wave PEEK substrate


 
 X-Ray picture after a spinal interbody fusion: thanks to the titanium markers inserted in the PEEK cage, we can localize the medical device in the patient and observe the bone ingrowth in the same time

Orchid Switzerland has both the machinery for surface engineering with VPS capabilities and the know-how to manufacture and coat specific parts for world leading customers. We have coated more than 100,000 of very various PEEK cages with titanium for spinal applications.

By Armando Salito, Global Technical Director


Read our white paper about Ti on PEEK! These results provide quantitative guides for the design of orthopedic implants for which such coating is used to enhance anchorage to bone tissues.