Chromium ion release from stainless steel pediatric scoliosis instrumentation.
METHODS
Case-control study.


OBJECTIVE
To determine whether serum metal ion levels and erythrocyte chromium levels in adolescents with stainless steel spinal instrumentation are elevated when compared with 2 control groups.


BACKGROUND
Instrumented spinal arthrodesis is a common procedure to correct scoliosis. The long-term consequences of retained implants are unclear. Possible toxic effects related to raised metal ion levels have been reported in the literature.


METHODS
Thirty patients who underwent posterior spinal arthrodesis with stainless steel instrumentation for scoliosis (group 1) were included. Minimum postoperative duration was 3 years. Serum chromium, molybdenum, iron, and ferritin levels were measured. Participants with elevated above normal serum chromium levels (n = 11) also underwent erythrocyte chromium analysis. Comparisons were made with 2 control groups; 10 individuals with scoliosis with no spinal surgery (group 2) and 10 volunteers without scoliosis (group 3). All control group participants underwent serum and erythrocyte analysis.


RESULTS
Elevated above normal serum chromium levels were demonstrated in 11 of 30 (37%) group 1 participants. Elevated serum chromium levels were demonstrated in 0 of 10 participants (0%) in group 2 and 1 of 10 (10%) in group 3. There was a statistically significant elevation in serum chromium levels between group 1 and group 2 participants (P = 0.001). There was no significant association between groups 1, 2, and 3 for serum molybdenum, iron, and ferritin levels. Erythrocyte chromium measurements were considered within the normal range for all participants tested (n = 31).


CONCLUSIONS
Raised serum chromium levels were detected in 37% of patients following instrumented spinal arthrodesis for correction of scoliosis. This new finding has relatively unknown health implications but potential mutagenic, teratogenic and carcinogenic sequelae. This is especially concerning with most scoliosis patients being adolescent females with their reproductive years ahead.
Cundy
Thomas P
TP
Department of Orthopaedic Surgery, Women's and Children's Hospital, University of Adelaide, 72 King William Road, North Adelaide, SA 5006, Australia. pcundy@senet.com.au
Delaney
Christopher L
CL
Rackham
Matthew D
MD
Antoniou
Georgia
G
Oakley
Andrew P
AP
Freeman
Brian J C
BJ
Sutherland
Leanne M
LM
Cundy
Peter J
PJ
D000293:Adolescent; D000704:Analysis of Variance; D016022:Case-Control Studies; D002648:Child; D002857:Chromium / Q000032:analysis / Q000097:blood*; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D018579:Patient Selection; D012600:Scoliosis / Q000097:blood / Q000601:surgery*; D013123:Spinal Fusion / Q000295:instrumentation*; D013193:Stainless Steel; D013904:Thoracic Vertebrae / Q000601:surgery*; D055815:Young Adult
D002857:Chromium; D013193:Stainless Steel