Local and systemic metal ion release occurs intraoperatively during correction and instrumented spinal fusion for scoliosis

Abstract

Study designProspective pilot study.ObjectivesThe aim of this study was to measure titanium, niobium and aluminium levels in various intraoperative and postoperative samples to determine patterns of metal ion release that occur within the first month following instrumented spinal fusion.Summary of background dataRaised serum metal ion levels are reported following instrumented spinal fusion in adolescent idiopathic scoliosis. The exact topological origin and chronology of metal ion release remains conjectural. Recent literature suggests an immediate rise in serum metal levels within the first postoperative week.MethodsTitanium, niobium and aluminium levels were measured before, during and after surgery in serum and local intraoperative fluid samples obtained from two pediatric patients undergoing posterior correction and instrumentation for scoliosis.ResultsMeasurable metal ion levels were detected in all local samples obtained from wound irrigation fluid, cell saver blood, and fluid that immersed metal universal reduction screw tabs. Postoperative serum metal ion levels were elevated compared to baseline preoperative levels. In general, metal ion levels were considerably higher in the intraoperative fluid samples compared to those observed in the serum levels.ConclusionOur findings of contextually high metal ion concentrations in intraoperative and early postoperative samples provide further empirical support of a ‘putting-in’ phenomenon of metal ion release following instrumented spinal fusion. This challenges existing beliefs that metal ion release occurs during an intermediate ‘wearing-in’ phase. We recommend thorough irrigation of the operative site prior to wound closure to dilute and remove intraoperative metal ion debris. Possibilities of filtering trace metal ions from cell saver content may be considered.

Evaluation of Titanium Serum Levels in Patients After Spine Instrumentation: Comparison Between Posterolateral and 360º Spinal Fusion Surgery

“…They concluded that their findings of contextually high metal ion concentrations in intraoperative and early postoperative samples provide further empirical support of a "putting-in" phenomenon of metal ion release following instrumented spinal fusion. This complements existing beliefs that metal ion release occurs during an intermediate "wearing-in" phase [28]. Lukina et al, in a retrospective study of implantation of titanium growth guiding sliding instrumentation for scoliosis in children, reported that the content of titanium and vanadium ions in the whole blood of 90% of patients with implanted LSZ-4D TM (CONMET, Moscow, Russia) devices was increased as compared with the control group (2.8 and 4 times, respectively) but did not exceed the values reported previously in the literature for fusion spinal instrumentation.…”

“…Metal liberation from metallic implants has been reported in the body fluids of patients carrying total hip or knee replacements, intramedullary nails, and, more recently, in patients undergoing instrumental spinal arthrodesis [2][3][11][12][14][15][19][20][21][22][23][24][25][26][27][28][29][30].…”

“…There are few works in the literature on metal ion serum levels after deformity correction surgery. Those on serum titanium levels in patients with early-onset scoliosis or adolescent idiopathic scoliosis reported an increase in mean serum metal ion levels [26][27][28][29][30]. Cundy et al reported, in two prospective and longitudinal studies, that preoperative and postoperative concentrations of serum titanium and niobium were significantly different (p=0.0001), and median postoperative serum concentrations of titanium and niobium were elevated 2.4-and 5.9-folds above the normal range, respectively.…”

“…Metal ion release has been addressed in patients undergoing spinal surgery as correction of the deformity in adolescent idiopathic scoliosis literature or instrumented spinal arthrodesis [2][3]11,[25][26][27][28][29][30]. Localized metal debris has been well-documented in the paraspinal soft tissues surrounding instruments [3,5].…”

Does titanium in ionic form display a tissue-specific distribution?

“…Medical devices designed for such purposes can be made from a variety of biomaterials, but one of the most popular are Ti-based alloys (Geetha et al 2009 ). Many studies reported that titanium implants undergo biodegradation in the body (Matusiewicz 2014 ; Cundy et al 2015 ; Martín-Cameán et al 2015 ). Metal ions and biomaterial debris are released into peri-implant tissues as a result of corrosion and after this they can be transported by blood [Ti(IV) ions bound to transferrin] to other biocompartments (tissues) (Soto-Alvaredo et al 2014 ; Zierden and Valentine 2016 ).…”