# Accuracy of novel custom 3D-printed metal and polymer cutting guides for segmental mandibulectomy in the dog: a cadaveric study

## TL;DR

This study tested custom 3D-printed surgical guides for dog jaw surgery, comparing metal and polymer materials for accuracy and performance.

## Contribution

The study introduces custom 3D-printed surgical guides for canine mandibulectomy and evaluates material-specific performance differences.

## Key findings

- Polymer guides allowed faster and easier placement compared to metal guides.
- Metal guides showed no material failure but had issues with displacement and gap formation.
- No significant difference in surgical accuracy was found between the two materials.

## Abstract

The objectives of this study were to design a 3D-printed custom guide for segmental mandibulectomy in the dog and evaluate the impact of different materials (metal versus polymer) on the performances of the guided procedure in cadaveric dogs.

Twenty canine cadaveric heads were randomized in two study groups and received bilateral segmental mandibulectomies performed with a metal or polymer surgical guide. Pre-operative computed tomography (CT) images of the skull were used to design custom 3D-printed surgical guides and were repeated after placement and osteotomy. Mean absolute linear deviation between planned and performed cuts, procedure duration, and qualitative assessment were compared.

Polymer guides were associated with easier (p =0.020) and faster (p =0.004) placement. No incidence of failure was recorded when using metal guides, whereas 30 and 15% of polymer guides experienced cracking and fissuring, respectively (p =0.001). Dorsal displacement and gap formation between guide and mandibular body was noted in 7/20 metal guides on CT. Mean absolute linear deviation between planned and performed cuts was not significantly different between material groups (p =0.612). Polymer guides presented several advantages including efficient placement despite a high incidence of material failure. Difficulty of placement encountered with metal guides relates to the rigidity of the material. However, these limitations did not have any significant impact on surgical accuracy.

Overall, the study did not demonstrate any difference in accuracy between materials but highlighted differences in performance specific to each material. Thus, surgical guide manufacturing and material choice could be tailored to specific clinical applications, whether strength/durability or flexibility/conformability is favored.