title: Metal concentrations in the blood and tissues after implantation of titanium growth guidance sliding instrumentation.
abstract: BACKGROUND
  Growth guidance sliding treatment devices, such as Shilla (Medtronic, Minneapolis, MN USA) or LSZ-4D (CONMET, Moscow, Russia), used for the treatment of scoliosis in children who have high growth potential have unlocked fixtures that allow rods to slide during growth of the spine, which avoids periodical extensions. However, the probability of clinical complications associated with metallosis after implantation of such devices is poorly understood. The content of metal ions in the blood and tissues of pediatric patients treated for scoliosis using fusionless growth guidance sliding instrumentation has not yet been investigated.
  
  
  OBJECTIVE
  The aim of the present study was to measure the content of metal ions in the blood and tissues surrounding the implanted growth guidance sliding LSZ-4D devices made of titanium alloy (Ti6Al4V), and to identify the incidence of metallosis-associated clinical complications in some patients with these devices.
  
  
  METHODS
  This is a one-center, case-control retrospective study.
  
  
  METHODS
  The study group included 25 patients with high growth potential (22 females, 3 males; average age at primary surgery for scoliosis treatment is 11.4±1.2 years old) who had sliding growth guidance instrumentation LSZ-4D (CONMET) implanted on 13 (range: 10-16) spine levels for 6±2 years. The LSZ-4D device was made from titanium alloy Ti6Al4V and consisted of two rectangular section rods and fixture elements. Locked fixtures were used on one spinal level, whereas the others were unlocked (sliding). The control group consisted of 13 patients (12 females and 1 male; 11±1.2 years old) without any implanted devices.
  
  
  METHODS
  The content of Ti, Al, and V metal ions in the whole blood and tissues around the implanted device was measured. The incidences of metallosis-associated complications in the study group were recorded.
  
  
  METHODS
  Metal ion content was measured by the inductively coupled mass spectrometry method on quadrupolar NexION 300D (PerkinElmer Inc, Shelton, CT, USA).
  
  
  RESULTS
  Five of 25 patients in the study group developed metallosis-associated complications (two sinuses and three seroma in the lumbar part of the spine). Revisions were carried out in two of these patients. Ninety percent of the patients in the study group had increased content of Ti and V ions in the blood (2.8 and 4 times, respectively). Median content of Ti ions in soft tissues adjacentto implanted sliding device was more than 1,500-fold higher than that of the control group. These levels are much higher than previously reported for spinal instrumentation.
  
  
  CONCLUSIONS
  Increased content of Ti and V ions in the blood and especially in tissues around the titanium growth guidance sliding device LSZ-4D accompanied by clinical manifestations (seroma and sinuses) indicates the importance of improving wear resistance of such instrumentation with the coatings and the necessity to exchange sliding instrumentation once the child is fully grown.
authors.affiliation: Kingston University London, SW15 3DW, Friars Avenue, London, UK; "MATI"-Russian State Technological University, 121552, Orshanskaya str., 3, Moscow, Russia. Electronic address: elenaalukina@rambler.ru.
authors.forename: Elena
authors.initials: E
authors.lastname: Lukina
authors.affiliation: Russian University of People's Friendship, 117198, Miklykho-Maklaya street, 6, Moscow, Russia.
authors.forename: Aleksandr
authors.initials: A
authors.lastname: Laka
authors.affiliation: "MATI"-Russian State Technological University, 121552, Orshanskaya str., 3, Moscow, Russia.
authors.forename: Mikhail
authors.initials: M
authors.lastname: Kollerov
authors.affiliation: Russian University of People's Friendship, 117198, Miklykho-Maklaya street, 6, Moscow, Russia.
authors.forename: Mykhamad
authors.initials: M
authors.lastname: Sampiev
authors.affiliation: Kingston University London, SW15 3DW, Friars Avenue, London, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Mason
authors.affiliation: Kingston University London, SW15 3DW, Friars Avenue, London, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Wagstaff
authors.affiliation: Royal National Orthopaedic Hospital, HA7 4LP Brockley Hill, Stanmore, London, UK.
authors.forename: Hilali
authors.initials: H
authors.lastname: Noordeen
authors.affiliation: Royal National Orthopaedic Hospital, HA7 4LP Brockley Hill, Stanmore, London, UK; University College London, HA7 4LP Brockley Hill, Stanmore, London, UK; Royal Adelaide Hospital, North Terrace, 5000, Adelaide, Australia.
authors.forename: Wai Weng
authors.initials: WW
authors.lastname: Yoon
authors.affiliation: University College London, HA7 4LP Brockley Hill, Stanmore, London, UK.
authors.forename: Gordon
authors.initials: G
authors.lastname: Blunn
mesh_terms: D000293:Adolescent; D000497:Alloys; D000535:Aluminum / Q000097:blood* / Q000506:poisoning; D016022:Case-Control Studies; D002648:Child; D005260:Female; D005402:Fistula; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D011041:Poisoning / Q000097:blood; D011183:Postoperative Complications / Q000097:blood*; D019736:Prostheses and Implants; D012189:Retrospective Studies; D012600:Scoliosis / Q000601:surgery*; D049291:Seroma; D013131:Spine / Q000601:surgery; D014025:Titanium / Q000097:blood* / Q000506:poisoning; D014639:Vanadium / Q000097:blood* / Q000506:poisoning
chemical_list: D000497:Alloys; D014639:Vanadium; C031462:titanium alloy (TiAl6V4); D000535:Aluminum; D014025:Titanium
keywords: Metal ion content; Metallosis; Scoliosis; Sliding instrumentation; titanium; wear