"Custom" Plate in a Day-Accurate Predictive Hole Fabrication Using Point-of-Care 3-Dimensional Printing.

PURPOSE: In computer surgical planned (CSP) fibular reconstructions of the mandible, custom plates facilitate accurate and efficient transfer of the digital plan intraoperatively by a way of predrilled fixation holes. Stock plates are more easily accessible and are more economical but typically preclude the utilization of these predictive holes. The purpose of this article is to describe an accurate and economical alternative to custom plates, while still having the ability to create predictive holes for plate alignment and execution of a digital surgical plan.

METHODS

An in vitro accuracy study was performed on a point-of-care resin-printed predictive hole guide termed "prebent plate analog" (PPA). Twenty stock 2.0 reconstruction plates prebent against a 3-dimensional printed mandibular model reconstructed with a 2-piece fibula were used to fabricate 20 PPAs. The proximal and distal 4 holes of each prebent plate and corresponding PPA were assessed using a heat map overlay, measuring difference in millimeters between matching points of the predictive hole segments. The median distance from the points of reference in the PPA versus the prebent plate was calculated for each predictive hole position in addition to the average error of the PPA to the stock plate.

RESULTS

Eighteen PPAs were used for statistical analysis; 2 were damaged in transport. The mean error between the body (-0.265) and condylar segments (-0.116 mm) and mean difference in error between the proximal predictive holes (-0.124 mm) and distal predictive holes (-0.215 mm) on the PPA were not statistically different (P = .061, P = .314 general estimating equation regression, respectively). The mean error across the PPA predictive holes and corresponding holes of the prebent plates was -0.194 mm (P < .001, general estimating equation regression).

CONCLUSIONS

The PPA is a precise and accurate analog that faithfully replicates the position of proximal and distal components of a prebent stock plate, thereby allowing for predictive hole placement in lieu of a custom plate in fibula mandibular reconstruction cases.