Cranioplasty and Craniofacial Reconstruction: A Review of Implant Material, Manufacturing Method and Infection Risk

Abstract

Background: Analysis of current literature highlights a wide variation in reported infection risk for different materials in cranial repair. The purpose of these composite materials are to mimic natural bone and assist in restoring function (structurally and aesthetically) to the human skull. This review aims to examine the meta-data in order to provide an amalgamated overview of potential trends between implant material, manufacturing method and infection risk, in order to provide a core reference point for future studies surrounding emerging biomedical materials in the fields of cranioplasty by providing base point for understanding the capabilities and limitations of current technologies. Methods: A search for articles was conducted, with the following criteria seen as fundamental in providing an accurate picture of the current landscape: publication in the last decade, provision of a numerical value for both number of implants and infection cases, patient sample of 10+, adult patients, and cranioplasty/cranial repair. Results: A total of 41 articles were seen to meet the author's inclusion criteria. Average infection rates per material ranged between 2.04% and 10.98%. The results indicate that there is variation between materials in regards to total infection risk, however, depending on the materials compared, this value may be insignificant. Alternative risk factors associated with infection, including surgical time, revisions and previous infection, have a greater impact on infection potential than material variation. Comparison of fabrication methods did highlight a notable effect on average infection rate. Trends can be observed showing that materials with greater levels of surface interaction and active support of tissue ingrowth presented greater infection resistance. Such characteristics are due to the physical structures of the implants. Conclusions: It can be said that the manufacturing methods can influence biomedical materials to assist in minimizing implant infection risk.

Evaluation of neurosurgical implant infection rates and associated pathogens: evidence from 1118 postoperative infections

“…68,85 Neurosurgical implants include fixation devices for craniotomy, synthetic cranioplasties, various polymers, metal or ceramic materials, internal shunt systems, external ventricular drains, and neurostimulators. 51 When comparing the IRs of different implants, it is essential to recognize differences such as material properties, biocompatibility, and bioactivity. Autologous bone is not subject to immune rejection and is effective as a substrate for bone ingrowth and revascularization.…”

“…Forms of titanium used in neurosurgical procedures can be further split into titanium mesh and titanium plates. 51 Titanium implants often require prefabrication, 18,25 leading to an increased lead time and cost, and intraoperative alteration remains difficult. 4 In this study, the number of titanium implants was 810, with an average IR of 8.15%, which should cause the clinician to be cautious with their use.…”

“…This suggests that publication bias cannot be absolutely excluded even though no significant publication bias was observed. 51 It was impossible to completely exclude the influence of confounding factors inherent in these included studies, although subgroup analyses by population, sex, region, periods of time, and study design were performed. Third, the other limitation is that our analysis was based on data obtained from retrospective articles, which possibly makes it difficult to avoid and assess bias.…”

“Hybrid Reconstruction” for Zygomaticomaxillary Complex Defect Using CAD/CAM: A Case Report

“… 2 – 4 PMMA is a reliable material with good strength and low infection rates vis-a-vis polyether ether ketone, titanium, etc. 5 …”

Reconstruction of Cranial Defect With Individualized PEEK Implant: Case Report

“…The cranioplasty procedure is one of the oldest procedures performed in neurosurgery, and consists of surgically repairing a cranial defect, generally in a delayed manner, in order to decrease the risk of graft infections [1]. There are various indications for this technique, all with the main objective of supporting the underlying noble structures, along with restoring shape and aesthetics [2]. Contraindications include infections, hydrocephalus, and cerebral edema [3].…”