Refined methodology for implantation of a head fixation device and chronic recording chambers in non-human primates

Abstract

The present study was aimed at developing a new strategy to design and anchor custom-fitted implants, consisting of a head fixation device and a chronic recording chamber, on the skull of adult macaque monkeys. This was done without the use of dental resin or orthopedic cement, as these modes of fixation exert a detrimental effect on the bone. The implants were made of titanium or tekapeek and anchored to the skull with titanium screws. Two adult macaque monkeys were initially implanted with the head fixation device several months previous to electrophysiological investigation, to allow optimal osseous-integration, including growth of the bone above the implant's footplate. In a second step, the chronic recording chamber was implanted above the brain region of interest. The present study proposes two original approaches for both implants. First, based on a CT scan of the monkey, a plastic replicate of the skull was obtained in the form of a 3D print, used to accurately shape and position the two implants. This would ensure a perfect match with the skull surface. Second, the part of the implants in contact with the bone was coated with hydroxyapatite, presenting chemical similarity to natural bone, thus promoting excellent osseous-integration. The longevity of the implants used here was 4 years for the head fixation device and 1.5 years for the chronic chamber. There were no adverse events and daily care was easy. This is clear evidence that the present implanting strategy was successful and provokes less discomfort to the animals.

Role of primary motor cortex in the control of manual dexterity assessed via sequential bilateral lesion in the adult macaque monkey: A case study

“…Anesthesia for surgical procedures was described in detail in a recent report from this laboratory (Lanz et al, 2013). Sedation was induced with a mixture of ketamine (KetanarkonÒ; 10 mg/kg; i.m.…”

3D printing and modelling of customized implants and surgical guides for non-human primates

“…Commercial orthopaedic and dental implants are coated with HA granules, to promote osseointegration between the bone and the implant (Søballe et al, 1990, Cook et al, 1992, Lanz et al, 2013, Raphel et al, 2016). The bottom surfaces of our implants were plasma sprayed with HA by the company Medicoat AG (Mägenwil, Switzerland), at a cost of €230 per implant.…”

“…In previous studies, customized implants were designed using anatomical scans of the individual animal's skull, ensuring a good fit between the bone and the implant, reducing the duration of surgery, and decreasing the likelihood of granulation tissue growth and infection (McAndrew et al, 2012, Lanz et al, 2013). These implants were typically manufactured using computer numerical control (CNC) machines, which use traditional milling methods to ‘sculpt’ objects out of a solid block of starting material, under the control of computer-aided design (CAD) programmes.…”

“…These implants were typically manufactured using computer numerical control (CNC) machines, which use traditional milling methods to ‘sculpt’ objects out of a solid block of starting material, under the control of computer-aided design (CAD) programmes. Several research labs carry out their design process and production using CAD software and CNC machines, either in-house (Galashan et al, 2011, Lanz et al, 2013, Mulliken et al, 2015) or outsourced to a CNC workshop (Adams et al, 2007) or a company that specializes in such implants (Johnston et al, 2016). Several companies offer CNC milling services to create customized solutions for a small range of implantable products (e.g.…”

“…The benefits of bringing 3D modelling technologies into the field of primate neurobiology have previously been highlighted by McAndrew et al (2012) and Lanz et al (2013). McAndrew et al designed their customized recording chambers using costly software packages (Mimics and SolidWorks), and in both studies, the chambers were then manufactured from radiolucent PEEK material, using CNC milling techniques.…”