Design of 3D Additively Manufactured Hybrid Structures for Cranioplasty.

Roberto De Santis,Antonio Gloria,Teresa Russo,Julietta V Rau,Ida Papallo,Massimo Martorelli

doi:10.3390/ma14010181

Abstract

A wide range of materials has been considered to repair cranial defects. In the field of cranioplasty, poly(methyl methacrylate) (PMMA)-based bone cements and modifications through the inclusion of copper doped tricalcium phosphate (Cu-TCP) particles have been already investigated. On the other hand, aliphatic polyesters such as poly(ε-caprolactone) (PCL) and polylactic acid (PLA) have been frequently investigated to make scaffolds for cranial bone regeneration. Accordingly, the aim of the current research was to design and fabricate customized hybrid devices for the repair of large cranial defects integrating the reverse engineering approach with additive manufacturing, The hybrid device consisted of a 3D additive manufactured polyester porous structures infiltrated with PMMA/Cu-TCP (97.5/2.5 w/w) bone cement. Temperature profiles were first evaluated for 3D hybrid devices (PCL/PMMA, PLA/PMMA, PCL/PMMA/Cu-TCP and PLA/PMMA/Cu-TCP). Peak temperatures recorded for hybrid PCL/PMMA and PCL/PMMA/Cu-TCP were significantly lower than those found for the PLA-based ones. Virtual and physical models of customized devices for large cranial defect were developed to assess the feasibility of the proposed technical solutions. A theoretical analysis was preliminarily performed on the entire head model trying to simulate severe impact conditions for people with the customized hybrid device (PCL/PMMA/Cu-TCP) (i.e., a rigid sphere impacting the implant region of the head). Results from finite element analysis (FEA) provided information on the different components of the model.

Highlights

Cranioplasty is the surgical procedure for correcting cranial deformities or defects arising from skull fracture, deformities, cancer and infections
Represents the most common approach. This cement consists of a solid powder phase made of poly(methyl methacrylate) (PMMA) and a liquid monomer; by mixing these two phases, a radical polymerization reaction occurs driven by benzoyl-peroxide and amines [4,5,6]. Such biomaterial is used for bone reconstruction from more than half a century, and the cranioplasty procedure consists of a single intra-operatively step [7], as the malleable paste is applied onto the cranial defect, and it is shaped around the contours of the patient’s skull defects [4,8]
Even though the direct impact mainly caused the failure of some elements of the external cement layer, the analysis provided values of cerebral spinal fluid (CSF) minimum pressure and brain von Mises stress which should not lead to subdural hematomas (SDH)

Summary

Introduction

Cranioplasty is the surgical procedure for correcting cranial deformities or defects arising from skull fracture, deformities, cancer and infections. This cement consists of a solid powder phase made of PMMA and a liquid monomer; by mixing these two phases, a radical polymerization reaction occurs driven by benzoyl-peroxide and amines [4,5,6]. Such biomaterial is used for bone reconstruction from more than half a century, and the cranioplasty procedure consists of a single intra-operatively step [7], as the malleable paste is applied onto the cranial defect, and it is shaped around the contours of the patient’s skull defects [4,8]. In order to prevent cranioplasty graft infections [4,12], gentamicin has been loaded into PMMA [13,14], but a reduction in mechanical properties has been shown [6]

Objectives

Methods

Results

Conclusion