Detection of Titanium Particles in Soft Tissues Adjacent to the Fixators in Patients with Facial Fractures and Bone Defects

Abstract

Background: Open reposition and rigid internal fixation are the main methods of treatment for traumatic injuries of the facial skull and an important stage of bone-plastic, reconstructive, and orthognathic surgery. In contemporary maxillofacial surgery, fixators, implants, and endoprostheses made of titanium or its alloys are widely used due to the high corrosion resistance and biocompatibility. However, recent studies have shown that none of the metal implants used in maxillofacial surgery, orthopedics or traumatology is completely inert. Moreover, they always interact with the surrounding biological environment. Thus, a number of studies have revealed the release of titanium to the adjacent soft tissues. Material and Methods: Titanium fixators (plates and screws) removed in 12 patients in late terms after osteosynthesis, as well as biopsies of the periosteum and fibrous capsule adjacent to the fixation elements made of titanium were investigated. Microscopic fluorescence spectroscopic analysis (M4 TORNADO micro-ray fluorescence spectrometer; Bruker, Bremen, Germany) was used to determine the elemental composition of the removed soft tissue fragments. Scanning electron microscopy (microscope model JSM-6060; JEOL, Japan) was used to study structural changes on the surface of titanium plates and screws. The obtained results were analized with the use of Spirman correlation coefficient, calculated by the IBM SPSS Statistics v.23 software. Results: X-ray fluorescence analysis revealed the inclusion of titanium in all investigated samples with an average content of titanium 48.14% ± 31.1% in metal deposition areas. For samples removed in patients with traumatic facial fractures after metallosteosynthesis, the average content of titanium was 55.6%, and for reconstructive surgeries – 37.72%. The acquired maps of the element deposition showed no topographic inhomogenity of titanium particles distribution. The main distribution patterns were the following: 1) areas of clearly outlined intensive titanium inclusions (90.9-800 μm), and 2) diffuse titanium inclusions which were poorly demarcated. Electronic microscopy of the investigated fixators revealed deformation of the thread, bending of screws, deformation and surface defects of the plates caused by mechanical damage, including microcracks, sharp edges, scratches, dimples.