Improved methods for acrylic-free implants in nonhuman primates for neuroscience research

Area of Science:

• Neuroscience
• Biomedical Engineering
• Veterinary Surgery

Background:

• Traditional head fixation devices in nonhuman primates (NHP) utilize dental acrylic, which has significant drawbacks.
• Biocompatible materials like titanium and PEEK are increasingly favored for NHP research implants.
• Existing methods often involve lengthy surgeries and potential complications.

Purpose of the Study:

• To describe a cost-effective procedure for implanting headposts and recording cylinders in NHP.
• To maximize tissue integration and reduce surgery time using 3D-printed skull replicas.
• To enhance the longevity and reduce complications associated with cranial implants in NHP.

Main Methods:

• Utilized 3D-printed replicas of rhesus monkey skulls based on CT scans.
• Custom-shaped titanium headpost feet and recording cylinders to precisely fit the skull.
• Preoperative measurement of skull thickness to optimize implant fit and reduce surgery time (up to 70% reduction).

Main Results:

• Implants were fabricated using biocompatible titanium, avoiding acrylic.
• Recording chambers remained watertight for 8.5 months.
• No bone exposure occurred; skin retracted but remained adhered to the skull.
• Headposts remained functional without complications for over 4 years in some cases.

Conclusions:

• The described acrylic-free implantation method is cost-effective and reduces surgery time.
• 3D-printed skull replicas facilitate precise fabrication and improve implant integration.
• This approach enhances the functional lifespan and safety of cranial implants for NHP neurophysiology research.