EOS Surgical GuidesFHC has transformed stereotaxy in neurosurgery using a 3D modelling process based on each patient’s anatomical coordinates. A unique operating platform is then produced in an EOS Formiga P 100 machine, which selectively melts successive layers of plastic powder using a computer controlled laser.
Neurologists whose patients suffer from Parkinson's disease, tremor, dystonia and other disorders including chronic pain are increasingly using deep brain stimulation (DBS) to treat the conditions and alleviate the acute symptoms. Electrodes inserted to very high accuracy into selected regions of the brain are able to provide remarkable therapeutic benefits where medication fails.
Additive manufacturing (AM) technology from the German firm, EOS, is helping one US surgical equipment manufacturer, FHC Inc, to produce more precisely, quickly and economically the electrode insertion guide frames needed for DBS. It is a good example of the way in which AM can benefit the consumer by facilitating production of bespoke components suited to their individual needs.
In this case, patients are saved a gruelling traditional procedure whereby stereotactic frames fix the patient’s head for many hours of MRI and CT scanning, target identification and electrode implantation within brain tissues, all performed while the person is awake.
Instead, to prevent head movement during these critical procedures, a custom made platform is fixed directly to three or four anchor points on the patient's skull. It provides a unique mounting interface that allows the surgical plan, ie the selected target and trajectory of the electrodes, to be built directly into the geometry of the fixture. In other words, the attachment is customised to suit not only the patient's anatomy, but also the microdrive aligning and DBS lead placement procedures.
All of this takes place before the person is operated upon, saving time and cost in the theatre, where the time required for a typical bilateral neurosurgical procedure is reduced by an average of two hours. More importantly, the patient enjoys a greater degree of comfort by allowing some degree of head movement. In addition, neuronal targetting and lead placement are more efficient.
FHC had previously been using various layer-by-layer AM techniques to build the platforms in its Maine production facility. However, as demand for the device grew, the company wanted to reduce production turnaround times and costs, and more easily accommodate surgeon’s special designs, while increasing the precision of the finished products.
The so-called STarFix customised stereotactic fixtures are now manufactured from PA 2201 polyamide powder in an EOS Formiga P machine. From receipt of a patient's file, turnaround time to supply of the custom mounting interface is around 24 hours in the US, 72 hours in Europe.
Fred Haer, CEO of FHC, said: "We are very pleased with the advances in additive manufacturing since STarFix technology was patented in 2001. To meet our exacting standards, we moved our primary production of the fixture to an EOS FORMIGA P 100 laser-sintering system in 2011.
“We are also looking to expand development of enabling products into other surgical specialties such as orthopaedics and EOS equipment offers a solution to these multiple needs.”
The switch to manufacture using EOS technology has provided numerous benefits to FHC. STarFix Chief Technology Officer, Ron Franklin, commented “The Formiga machine is smaller, lighter and more accurate than what we were using before, added to which we have been able to include new functionality into the platform while reducing the cost of materials and processing.”
"We are able to build more parts into the platform and include additional features that simplify the mounting of various devices, so it is more precise and assembly time in the operating theatre is reduced.
"One example is a metal indexing ring that was formerly screwed onto the platform during surgery. Now we can incorporate that function within the finished fixture.
“This saves us the effort of having to provide that machined part separately and saves theatre time because they do not have to sterilise the part and keep track of small, loose screws during surgery.”
Consumable savings are another benefit of the machine. FHC finds it economical to operate, as all of the EOS polyamide powder added to the system is used, so there is less material consumption.
Mr Haer concluded: "We anticipate even greater product improvement opportunities from the switch to EOS AM technology as we go forward.
"It provides us with patient-specific product manufacturing while enabling us to control costs as we speed delivery to our surgical customers.
“Having the flexibility of a technology that can create tailored rather than one-size-fits-all solutions also result in hospital economies and better patient outcomes."