Carlos Veuthey

Peripheral nerve injuries, especially neurotmesis, require precise repair strategies due to their severity and limited capacity for spontaneous regeneration. Nerve guidance conduits (NGCs) offer a promising alternative to autografts; however, consistent surgical techniques and anatomical references in rodent models could be enhanced. This ex vivo study focuses on describing and establishing a standardized, reproducible anatomical and technical protocol for implanting an NGC in the sciatic nerve of Wistar rats, identifying a 7 mm segment free of collateral branches as a safe site for neurotmesis. Thirty cadaveric hind limbs were positioned in lateral decubitus, and anatomical landmarks such as the greater trochanter, ischial bone, and femoral condyle guided the incision. A 1 cm scaffold was inserted and secured with 8-0 absorbable sutures, while muscle and skin were closed with 5-0 and non-absorbable sutures. The technique enabled safe access to the nerve, minimized risk to adjacent structures, and ensured proper scaffold positioning without tension. This standardized approach improves surgical reproducibility and supports anatomical integrity; however, because the study used ex vivo cadaveric samples, its capacity to facilitate functional nerve regeneration remains theoretical. While the protocol emphasizes the importance of surgical planning and suture patterns, it cannot account for active biological processes such as angiogenesis, inflammatory response, or axonal growth, which are critical for successful repair. Ultimately, this study provides a reliable anatomical platform for NGC evaluation under controlled experimental conditions, serving as a necessary precursor to in vivo validation of safety and functional outcomes.

Background/Objectives: Plastination with polyester resin is a consolidated technique for anatomical preservation, particularly valuable in neuroanatomy education and radiological correlation. This review synthesizes the principles, technical evolution, methodological variations, applications, and limitations of polyester-based sheet plastination methods (P35, P40, P45). Methods: Key documents were analyzed to trace the transition from P35, recognized for excellent gray-white matter contrast but technical complexity, to P40, offering greater transparency, lower viscosity, improved strength, and simplified UV-curing. P45 was also reviewed, especially for large body sections using water-bath curing. Innovations included vertical curing chambers, active-passive vacuum cycles, resin reformulations, and strategies to reduce tissue shrinkage. Methodological quality was assessed with the AQUA tool, which evaluates five domains: Objectives, Study Design, Methodology, Descriptive Anatomy, and Results Reporting. Results: Plastination proved applicable in medical and veterinary education, as well as morphometric and imaging-based research, improving anatomical understanding and CT/MRI correlation. AQUA analysis revealed low risk of bias in Objectives and Descriptive Anatomy, but frequent unclear or high-risk assessments in Study Design, Methodology, and Results Reporting, mainly due to limited details on sample selection, resin handling, curing, and reproducibility. Publications after 2010 showed improved methodological rigor, reflecting growing standardization and better reporting. Conclusions: Polyester sheet plastination remains a versatile, high-impact tool, though it requires specialized infrastructure, trained personnel, and strict environmental control. Future development should focus on protocol standardization, international dissemination, integration with digital technologies (3D models, virtual reality), and sustainable alternatives. Progress depends on inter-institutional collaboration, technical training, and open access to updated resources.

Peri-implantitis is an inflammatory condition characterized by inflammation in the peri-implant connective tissue and a progressive loss of supporting bone; it is commonly associated with the presence of biofilms on the surface of the implant, which is an important factor in the development and progression of the disease. The objective of this study was to evaluate, using micro-CT, the bone regeneration of surgically created peri-implant defects exposed to a microcosm of peri-implantitis. Twenty-three adult New Zealand white rabbits were included in the study. Bone defects of 7 mm diameter were created in both tibiae, and a cap-shaped titanium device was placed in the center, counter-implanted with a peri-implantitis microcosm. The bone defects received a bone substitute and/or a resorbable synthetic PLGA membrane, according to random distribution. Euthanasia was performed 15 and 30 days postoperatively. Micro-CT was performed on all samples to quantify bone regeneration parameters. Bone regeneration of critical defects occurred in all experimental groups, with a significantly greater increase in cases that received bone graft treatment (p < 0.0001), in all measured parameters, at 15 and 30 days. No significant differences were observed in the different bone neoformation parameters between the groups that did not receive bone grafts (p > 0.05). In this experimental model, the presence of peri-implantitis microcosms was not a determining factor in the bone volume parameter, both in the groups that received regenerative treatment and in those that did not.