Assessment of corrosion in retrieved spine implants

Abstract

Recently the use of dissimilar metals in spine instrumentation has increased, especially in the case of adult deformities, where rods made from Cobalt Chrome alloys (CoCr) are used with Titanium (Ti) screws. The use of dissimilar metals increases the risk of galvanic corrosion and patients have required revision spine surgery due to severe metallosis that may have been caused by corrosion. We aimed to assess the presence of corrosion in spine implant retrievals from constructs with two types of material combinations: similar (Ti/Ti) and dissimilar (CoCr/Ti). First, we devised a grading score for corrosion of the rod-fixture junctions. Then, we applied this score to a collection of retrieved spine implants. Our proposed corrosion grading score was proven reliable (kappa > 0.7). We found no significant difference in the scores between 4 CoCr and 11 Ti rods (p = 0.0642). There was no indication that time of implantation had an effect on the corrosion score (p = 0.9361). We recommend surgeons avoid using implants designs with dissimilar metals to reduce the risk of corrosion whilst a larger scale study of retrieved spine implants is conducted. Future studies can now use our scoring system for spine implant corrosion. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 632-638, 2018.

Review of the local tissue reaction to metallic spinal implant debris: Ions and nanoparticles

“…A retrieval study by Kirkpatrick et al [16] identified three common modes of corrosion and wear that appear to happen simultaneously in vivo; fretting wear, crevice and galvanic corrosion. In a retrieval study conducted by Villarraga et al [17] and Panagiotopoulou et al [18] wear and corrosion were the most common types of damage seen on retrieved spinal hardware and they concluded that revision spine constructs contribute to this type of damage because of the additional segments and mobile pieces added.…”

“…Several case reports have been published on revision of spine components where the reason for revisions was strongly linked with corrosion and wear of the implants [14][15][16][17][18][19][20][21][22][23]. Medical complications included unexplained pain, neurological effects, implant loosening, implant failure, swelling and metal staining of the skin.…”

“…In the case of instrumentation that uses dissimilar methods, only preclinical testing has been performed [82] and neither post marker surveillance studies using blood metal ions, nor implant retrieval studies. Panagiotopoulou et al [18] described corrosion scores for the assessment of retrieval spinal implants with two types of material combinations: similar (Ti/Ti) and dissimilar (CoCr/Ti). Using this score, Authors found no evidence of increased corrosion when two different materials are galvanically coupled in spine instrumentation.…”

Metallic Implants Used in Lumbar Interbody Fusion

“…On the other hand, mixing dissimilar metals in spinal implants brings with it an increased risk of inducing galvanic corrosion [ 40 , 42 , 44 ]. However, biomechanical studies conducted in 0.9% sodium chloride at 37 °C and retrieval analyses of spinal instrumentation have shown no evidence of galvanic corrosion in spinal constructs made of different metals [ 42 , 45 , 46 ]. After the literature review, we compared breakdown potential to assess corrosion resistance of each discussed metal alloy ( Table 1 ).…”

Review on carbon nanomaterials as typical candidates for orthopaedic coatings

“…Regardless of the great progress of medical implants technology and it is suffered from a set of limitations to restrict the success rate up to some extent. Frequent issues related to orthopedic implants like corrosion, loosening of the device; due to poor mechanical strength, infection, non-integration of implant with host tissue and wearing are the prime factors of concerns [19,31,87]. The far most characteristic of an orthopedic implant is integration to host tissue to boost the success rate by resisting the colony formation of microbes and corrosion [23].…”