Session 8: Spine
Torsdag den 27. oktober
9:30 – 10:30
Lokale: Stockholm/Copenhagen
Chairmen: Cody Bünger / Dennis Hallager
Rune Tendal Paulsen, Mikkel Østerheden Andersen, Leah Carreon, Jamal Bech Bouknaitir, Søren Fruensgaard
Center for spine surgery and research, Middelfart; Center for spine surgery and research, Middelfart; Center for spine surgery and research, Middelfart; Ortopædkirugisk afdeling, Køge; Ortopædkirurgisk afdeling , Silkeborg
Background: Lumbar spinal stenosis (LSS) is a clinical syndrome of buttock or lower extremity pain, which may occur with or without back pain, associated with diminished space available for the neural and vascular elements in the lumbar spine. LSS is typically seen in elderly patients, with prevalence estimated to be 47% in people over the age 60. LSS is the most common reason for spine surgery in Denmark and the number of surgical procedures is likely to increase due to demographic changes.
Purpose / Aim of Study: The purpose of this study was to evaluate the patient reported outcomes and perioperative complications of spinal decompression surgery in patients with LSS.
Materials and Methods: This study is a retrospective study of prospectively collected data from 3420 consecutive patients with clinical and MRI confirmed LSS. Patients were treated with posterior decompression surgery between 2009 and 2014 at three regional centers in Denmark. Patients treated with concomitant fusion were excluded. Data were obtained from the DaneSpine register and collected pre- and postoperative after at least one year. Outcome measures were ODI, EQ-5D, VAS, MCS, PCS and self- reported walking distance.
Findings / Results: Of 3420 cases enrolled, 2591 (75%) had complete data after at least one year Mean ODI scores were 39,8 and improved to 24,0. Mean EQ-5D score was 0,40 and improved to 0,66. Mean VAS-leg improved from 54 to 36. Mean VAS-back improved from 46 to 34. Mean MCS improved from 28 to 36. Mean PCS improved from 40 to 45. All comparisons were statistically significant with p-values of 0,0000
Conclusions: Decompression surgery improved all patient-reported outcome measures (ODI, EQ5D, MCS, PCS, VAS and walking distance). Improvements were all of statistical and clinical relevance.
Center for spine surgery and research, Middelfart; Center for spine surgery and research, Middelfart; Center for spine surgery and research, Middelfart; Ortopædkirugisk afdeling, Køge; Ortopædkirurgisk afdeling , Silkeborg
Background: Lumbar spinal stenosis (LSS) is a clinical syndrome of buttock or lower extremity pain, which may occur with or without back pain, associated with diminished space available for the neural and vascular elements in the lumbar spine. LSS is typically seen in elderly patients, with prevalence estimated to be 47% in people over the age 60. LSS is the most common reason for spine surgery in Denmark and the number of surgical procedures is likely to increase due to demographic changes.
Purpose / Aim of Study: The purpose of this study was to evaluate the patient reported outcomes and perioperative complications of spinal decompression surgery in patients with LSS.
Materials and Methods: This study is a retrospective study of prospectively collected data from 3420 consecutive patients with clinical and MRI confirmed LSS. Patients were treated with posterior decompression surgery between 2009 and 2014 at three regional centers in Denmark. Patients treated with concomitant fusion were excluded. Data were obtained from the DaneSpine register and collected pre- and postoperative after at least one year. Outcome measures were ODI, EQ-5D, VAS, MCS, PCS and self- reported walking distance.
Findings / Results: Of 3420 cases enrolled, 2591 (75%) had complete data after at least one year Mean ODI scores were 39,8 and improved to 24,0. Mean EQ-5D score was 0,40 and improved to 0,66. Mean VAS-leg improved from 54 to 36. Mean VAS-back improved from 46 to 34. Mean MCS improved from 28 to 36. Mean PCS improved from 40 to 45. All comparisons were statistically significant with p-values of 0,0000
Conclusions: Decompression surgery improved all patient-reported outcome measures (ODI, EQ5D, MCS, PCS, VAS and walking distance). Improvements were all of statistical and clinical relevance.
Dennis Winge Hallager, Sven Karstensen, Naeem Bukhari, Martin Gehrchen, Benny Dahl
Spine Unit, Dept. of Orthopedic Surgery, Rigshospitalet, University of Copenhagen; Spine Unit, Dept. of Orthopedic Surgery, Rigshospitalet, University of Copenhagen; Spine Unit, Dept. of Orthopedic Surgery, Rigshospitalet, University of Copenhagen; Spine Unit, Dept. of Orthopedic Surgery, Rigshospitalet, University of Copenhagen; Spine Unit, Dept. of Orthopedic Surgery, Rigshospitalet, University of Copenhagen
Background: Mechanical failure rates following adult spinal deformity surgery is reported up to 37%. The importance of spinal alignment and balance is well documented for surgical outcome, however the role of these parameters as predictors for mechanical failure remains uncertain.
Purpose / Aim of Study: We aimed at evaluating radiographic predictors for mechanical failure following adult spinal deformity correction.
Materials and Methods: All adult spinal deformity patients having at least five thoracolumbar levels of instrumentation between 2008 and 2012 were included. Inability to measure pre- and postoperative SVA and radiography wearing a brace were exclusion criteria. Pre-, postoperative and change in coronal Cobb, central sacral vertical line, thoracic kyphosis (TK), lumbar lordosis (LL), sacral slope (SS) and sagittal vertical axis (SVA) were evaluated as predictors for mechanical failure using cause-specific Cox regression. Mechanical failure was defined as a revision procedure because of rod breakage, screw loosening or breakage, pseudarthrosis, fractures or symptomatic degeneration immediate above or below the instrumentation.
Findings / Results: 138 of 165 patients were included. Mean follow-up was 3.9 years (range 2.1-6.8). Median age at surgery was 61 years. Median 10 levels were instrumented with 71% ending at S1 and 44% had 3-column osteotomy performed. 47% had mechanical failure requiring revision during follow- up. Multivariate regression adjusting for age showed significant increased hazard from change in LL>30° (HR: 1.9 (95%CI: 1.0-3.4), P=0.038), postoperative TK>50° (HR: 1.9 (95%CI: 1.1-3.4), P=0.001) and postoperative SS≤30° (HR: 2.1 (95%CI: 1.3-3.5), P<0.001).
Conclusions: Change in LL>30°, postoperative TK>50° and postoperative SS≤30° independently increased the hazard of mechanical failure following adult spinal deformity correction.
Spine Unit, Dept. of Orthopedic Surgery, Rigshospitalet, University of Copenhagen; Spine Unit, Dept. of Orthopedic Surgery, Rigshospitalet, University of Copenhagen; Spine Unit, Dept. of Orthopedic Surgery, Rigshospitalet, University of Copenhagen; Spine Unit, Dept. of Orthopedic Surgery, Rigshospitalet, University of Copenhagen; Spine Unit, Dept. of Orthopedic Surgery, Rigshospitalet, University of Copenhagen
Background: Mechanical failure rates following adult spinal deformity surgery is reported up to 37%. The importance of spinal alignment and balance is well documented for surgical outcome, however the role of these parameters as predictors for mechanical failure remains uncertain.
Purpose / Aim of Study: We aimed at evaluating radiographic predictors for mechanical failure following adult spinal deformity correction.
Materials and Methods: All adult spinal deformity patients having at least five thoracolumbar levels of instrumentation between 2008 and 2012 were included. Inability to measure pre- and postoperative SVA and radiography wearing a brace were exclusion criteria. Pre-, postoperative and change in coronal Cobb, central sacral vertical line, thoracic kyphosis (TK), lumbar lordosis (LL), sacral slope (SS) and sagittal vertical axis (SVA) were evaluated as predictors for mechanical failure using cause-specific Cox regression. Mechanical failure was defined as a revision procedure because of rod breakage, screw loosening or breakage, pseudarthrosis, fractures or symptomatic degeneration immediate above or below the instrumentation.
Findings / Results: 138 of 165 patients were included. Mean follow-up was 3.9 years (range 2.1-6.8). Median age at surgery was 61 years. Median 10 levels were instrumented with 71% ending at S1 and 44% had 3-column osteotomy performed. 47% had mechanical failure requiring revision during follow- up. Multivariate regression adjusting for age showed significant increased hazard from change in LL>30° (HR: 1.9 (95%CI: 1.0-3.4), P=0.038), postoperative TK>50° (HR: 1.9 (95%CI: 1.1-3.4), P=0.001) and postoperative SS≤30° (HR: 2.1 (95%CI: 1.3-3.5), P<0.001).
Conclusions: Change in LL>30°, postoperative TK>50° and postoperative SS≤30° independently increased the hazard of mechanical failure following adult spinal deformity correction.
Dennis Karimi, Søren Morgen, Sidsel Fruergaard, Martin Gehrchen, Benny Dahl
Spine Section, Dept. of Orthopeadic Surgery, Rigshospitalet; Spine Section, Dept. of Orthopeadic Surgery, Rigshospitalet; , ; Spine Section, Dept. of Orthopeadic Surgery, Rigshospitalet; Spine Section, Dept. of Orthopeadic Surgery, Rigshospitalet
Background: Numerous pre-operative scoring systems based on clinical and imaging variables have been suggested to predict long-term survival in patients undergoing surgical treatment for symptomatic spinal metastasis, but the possible role of gender as an independent predictor of long-term survival has not been reported in studies with long time follow-up. Since 2005, Rigshospitalet, has been responsible for the treatment of patients with acute symptoms of spinal metastasis and serves as a referral unit for the Eastern half of the country. This organization makes it possible to follow a large group of patients with MSCC and to follow long-term outcomes.
Purpose / Aim of Study: To examine whether gender predicts long term survival in patients with symptomatic spinal metastasis after surgical treatment.
Materials and Methods: A prospective database including all patients referred with acute symptoms of spinal metastasis was established in 2005. Relevant variables were registered at referral including age, gender, and primary oncologic diagnosis. From January through December 2015 the survival status of all patients was obtained through the Central Office of Civil Registration.
Findings / Results: A total of 58 patients were operated for MSCC in 2005. The average age of the patients was 63 years and 55% were males. At the ten years follow-up 55 patients had died and the average survival time after surgery was 20 months. Survival time was significantly longer for females compared to males; 32 vs. 10 months (P<0.05). The hazard-ratio of 10- years survival for females was 2.12 (P< 0.01). This difference remained significant after adjusting for specific primary tumors and operation-age.
Conclusions: In spite of the small sample size, these results could indicate that gender should be included in pre- operative scoring systems used for patients with spinal metastasis.
Spine Section, Dept. of Orthopeadic Surgery, Rigshospitalet; Spine Section, Dept. of Orthopeadic Surgery, Rigshospitalet; , ; Spine Section, Dept. of Orthopeadic Surgery, Rigshospitalet; Spine Section, Dept. of Orthopeadic Surgery, Rigshospitalet
Background: Numerous pre-operative scoring systems based on clinical and imaging variables have been suggested to predict long-term survival in patients undergoing surgical treatment for symptomatic spinal metastasis, but the possible role of gender as an independent predictor of long-term survival has not been reported in studies with long time follow-up. Since 2005, Rigshospitalet, has been responsible for the treatment of patients with acute symptoms of spinal metastasis and serves as a referral unit for the Eastern half of the country. This organization makes it possible to follow a large group of patients with MSCC and to follow long-term outcomes.
Purpose / Aim of Study: To examine whether gender predicts long term survival in patients with symptomatic spinal metastasis after surgical treatment.
Materials and Methods: A prospective database including all patients referred with acute symptoms of spinal metastasis was established in 2005. Relevant variables were registered at referral including age, gender, and primary oncologic diagnosis. From January through December 2015 the survival status of all patients was obtained through the Central Office of Civil Registration.
Findings / Results: A total of 58 patients were operated for MSCC in 2005. The average age of the patients was 63 years and 55% were males. At the ten years follow-up 55 patients had died and the average survival time after surgery was 20 months. Survival time was significantly longer for females compared to males; 32 vs. 10 months (P<0.05). The hazard-ratio of 10- years survival for females was 2.12 (P< 0.01). This difference remained significant after adjusting for specific primary tumors and operation-age.
Conclusions: In spite of the small sample size, these results could indicate that gender should be included in pre- operative scoring systems used for patients with spinal metastasis.
Miao Wang, Cody Bünger, Abarajitha Thiyagarajah, MING SUN, EBBE STENDER HANSEN, HAISHENG LI, KESTUTIS VALANCIUS, PETER HELMIG, KRISTIAN HØY
Department of spine surgery, aarhus university hospital; Department of spine surgery, Aarhus University Hospital; Department of spine surgery, Aarhus University Hospital; Department of spine surgery, Aarhus University Hospital; Department of spine surgery, Aarhus University Hospital; Department of spine surgery, Aarhus University Hospital; Department of spine surgery, Aarhus University Hospital; Department of spine surgery, Aarhus University Hospital; Department of spine surgery, Aarhus University Hospital
Background: Adult scoliosis is a common disorder that is associated with significant pain, and functional impairment. Surgical treatment can significantly restore the function and improve the quality of life. However, the choice of lowest level of long fixation remains controversial for spine surgeons.
Purpose / Aim of Study: The aim of this study is to investigate the surgical outcome of iliac fixation and lumbosacral fixation in adult scoliosis patients.
Materials and Methods: We retrieved 78 adult patients with scoliosis in Aarhus University Hospital from March 2010 to May 2015. 63 female and 15 male patients. Average age is 64-year old. Pre- and postoperative X-ray and the revision operation were examined. McNemar test was used to compare the revision rate between two groups.
Findings / Results: In the lumbosacral fixation group, the lowest level of initial surgical fixation was selected as lumbar level (L4/L5) for 34 patients; sacrum level for 9 patients. The iliac level was selected for 35 patients. In total of 17 re-operations were performed. lumbar fixation group had 15 reoperations (15/34 pts, 44%). Sacrum fixation groups had 2 re-operations (2/9 pts, 22%). Iliac fixation groups had no reoperation. The reoperation rate of lumbosacral group is significant higher than iliac fixation group (p<.05). the 15 re- operated patients from lumbar group underwent different fixation surgeries. 3 another level fixation, 4 sacrum and 8 iliac fixation. two re- operated did not undergo extended surgery to level.
Conclusions: Long fusion surgery ended at lumbar level has the highest revision rate. The lowest level was selected as iliac level for adult scoliosis has significantly lower revision rate compared to lumbosacral level.
Department of spine surgery, aarhus university hospital; Department of spine surgery, Aarhus University Hospital; Department of spine surgery, Aarhus University Hospital; Department of spine surgery, Aarhus University Hospital; Department of spine surgery, Aarhus University Hospital; Department of spine surgery, Aarhus University Hospital; Department of spine surgery, Aarhus University Hospital; Department of spine surgery, Aarhus University Hospital; Department of spine surgery, Aarhus University Hospital
Background: Adult scoliosis is a common disorder that is associated with significant pain, and functional impairment. Surgical treatment can significantly restore the function and improve the quality of life. However, the choice of lowest level of long fixation remains controversial for spine surgeons.
Purpose / Aim of Study: The aim of this study is to investigate the surgical outcome of iliac fixation and lumbosacral fixation in adult scoliosis patients.
Materials and Methods: We retrieved 78 adult patients with scoliosis in Aarhus University Hospital from March 2010 to May 2015. 63 female and 15 male patients. Average age is 64-year old. Pre- and postoperative X-ray and the revision operation were examined. McNemar test was used to compare the revision rate between two groups.
Findings / Results: In the lumbosacral fixation group, the lowest level of initial surgical fixation was selected as lumbar level (L4/L5) for 34 patients; sacrum level for 9 patients. The iliac level was selected for 35 patients. In total of 17 re-operations were performed. lumbar fixation group had 15 reoperations (15/34 pts, 44%). Sacrum fixation groups had 2 re-operations (2/9 pts, 22%). Iliac fixation groups had no reoperation. The reoperation rate of lumbosacral group is significant higher than iliac fixation group (p<.05). the 15 re- operated patients from lumbar group underwent different fixation surgeries. 3 another level fixation, 4 sacrum and 8 iliac fixation. two re- operated did not undergo extended surgery to level.
Conclusions: Long fusion surgery ended at lumbar level has the highest revision rate. The lowest level was selected as iliac level for adult scoliosis has significantly lower revision rate compared to lumbosacral level.
Signe Forbech Elmose, Else Bay Andersen, Mikkel Østerheden Andersen
Center for Spine Surgery and Research, Middelfart Hospital; Department of Anesthesiology, Vejle Hospital; Center for Spine Surgery and Research, Middelfart Hospital
Background: Studies have shown that the antifibrinolytic drug TXA reduces blood loss during major spine surgery. There are no studies on the effect of TXA in minor lumbar spine surgery and no studies investigate the effect of TXA on OP-time.
Purpose / Aim of Study: We investigate the effect of tranexamic acid (TXA) compared to placebo in low- risk adult patients undergoing elective minor lumbar spine surgery. Primary objective is operative time (OP-time) and secondary objectives estimated perioperative (peri-OP) blood loss, incidence of dural tears, postoperative symptomatic spinal epidural hematomas (SEH) and venous thromboembolic events (VTE).
Materials and Methods: A clinical double blind randomized, placebo-controlled study. We included 220 patients (ASA 1-2), undergoing lumbar decompressive surgery at Middelfart Hospital. Exclusion criteria; thromboembolic disease, coagulopathy, hypersensitivity to TXA or history of convulsion. Randomization by blocks of 10, in two groups, TXA or placebo. Anticoagulation therapy was discontinued 2-7 days preoperatively. Patients received pre-incision either a bolus of TXA (10mg/kg IV), or an equivalent volume of placebo (saline). Statistics: Students t-test, Wilcoxon Mann-Whitney or chi2-test, significance level p=0.05.
Findings / Results: 14 patients were excluded, 206 analyzed (TXA-group n=103, placebo- group n=103). The groups had an unequal sex ratio TXA 49/51 and placebo 33/67 (female/male, %), otherwise comparable by basic demographics. There was no significant difference in OP-time. Statistical significant difference in estimated post-OP blood loss, median TXA 5ml (n=59) and placebo 21ml (n=64), p<0.001. No difference in per- OP blood loss or dural tears. No SEH or VTE.
Conclusions: A single dose of TXA can significantly reduce the post-OP blood loss in minor lumbar spine surgery on low-risk adult patients.
Center for Spine Surgery and Research, Middelfart Hospital; Department of Anesthesiology, Vejle Hospital; Center for Spine Surgery and Research, Middelfart Hospital
Background: Studies have shown that the antifibrinolytic drug TXA reduces blood loss during major spine surgery. There are no studies on the effect of TXA in minor lumbar spine surgery and no studies investigate the effect of TXA on OP-time.
Purpose / Aim of Study: We investigate the effect of tranexamic acid (TXA) compared to placebo in low- risk adult patients undergoing elective minor lumbar spine surgery. Primary objective is operative time (OP-time) and secondary objectives estimated perioperative (peri-OP) blood loss, incidence of dural tears, postoperative symptomatic spinal epidural hematomas (SEH) and venous thromboembolic events (VTE).
Materials and Methods: A clinical double blind randomized, placebo-controlled study. We included 220 patients (ASA 1-2), undergoing lumbar decompressive surgery at Middelfart Hospital. Exclusion criteria; thromboembolic disease, coagulopathy, hypersensitivity to TXA or history of convulsion. Randomization by blocks of 10, in two groups, TXA or placebo. Anticoagulation therapy was discontinued 2-7 days preoperatively. Patients received pre-incision either a bolus of TXA (10mg/kg IV), or an equivalent volume of placebo (saline). Statistics: Students t-test, Wilcoxon Mann-Whitney or chi2-test, significance level p=0.05.
Findings / Results: 14 patients were excluded, 206 analyzed (TXA-group n=103, placebo- group n=103). The groups had an unequal sex ratio TXA 49/51 and placebo 33/67 (female/male, %), otherwise comparable by basic demographics. There was no significant difference in OP-time. Statistical significant difference in estimated post-OP blood loss, median TXA 5ml (n=59) and placebo 21ml (n=64), p<0.001. No difference in per- OP blood loss or dural tears. No SEH or VTE.
Conclusions: A single dose of TXA can significantly reduce the post-OP blood loss in minor lumbar spine surgery on low-risk adult patients.
Peter Heide Pedersen, Søren Peter Eiskjær, Asger Greval Petersen
Orthopedic, Aalborg University hospital; Orthopedic, Aalborg University hospital; Røntgenfysik, Region North Jutland
Background: Ionizing radiation potentially leads to tissue damage. It has been documented in large cohort studies that radiographic imaging during childhood for spinal deformities eg. scoliosis, increases the lifetime risk of breast cancer. The EOS biplane x-ray imaging system (EOS Imaging S.A, Paris France) has been developed to produce high quality images while at the same time reducing radiation dose. At our institution we use the EOS for pre- and postoperative full spine examinations.
Purpose / Aim of Study: The purpose of the study is to make first time organ dose and effective dose evaluations with micro-dose settings in full spine examinations. Our hypothesis is that organ dose and effective dose can be reduced 5-10 times compared to standard settings, without too high image-quality trade off, resulting in a theoretical reduction of radiation induced cancer.
Materials and Methods: Patient dosimetry is performed on anthropomorphic child phantoms. Thermoluminiscent detectors are used to measure organ dose. A first time measurement with micro-dose settings in both AP and PA will be performed in addition to standard settings in AP and PA positions. Effective dose is calculated using mean organ doses and tissue weighting factors. These findings will be compared to previously reported findings in standard settings and to conventional digital x-ray(CR)
Findings / Results: In AP position we found a mean liver organ dose of 0.03mSv as compared to 0.25mSv with standard dose settings, a significant dose reduction of 88%. As expected the liver dose was higher in PA position than AP position, 0.05mSv vs. 0.03mSv.
Conclusions: Preliminary results with micro-dose settings show a 88% reduction of organ dose and a theoretical reduction of radiation induced cancer. Previously a 35% effective dose reduction was reported for the EOS in standard settings compared to CR.
Orthopedic, Aalborg University hospital; Orthopedic, Aalborg University hospital; Røntgenfysik, Region North Jutland
Background: Ionizing radiation potentially leads to tissue damage. It has been documented in large cohort studies that radiographic imaging during childhood for spinal deformities eg. scoliosis, increases the lifetime risk of breast cancer. The EOS biplane x-ray imaging system (EOS Imaging S.A, Paris France) has been developed to produce high quality images while at the same time reducing radiation dose. At our institution we use the EOS for pre- and postoperative full spine examinations.
Purpose / Aim of Study: The purpose of the study is to make first time organ dose and effective dose evaluations with micro-dose settings in full spine examinations. Our hypothesis is that organ dose and effective dose can be reduced 5-10 times compared to standard settings, without too high image-quality trade off, resulting in a theoretical reduction of radiation induced cancer.
Materials and Methods: Patient dosimetry is performed on anthropomorphic child phantoms. Thermoluminiscent detectors are used to measure organ dose. A first time measurement with micro-dose settings in both AP and PA will be performed in addition to standard settings in AP and PA positions. Effective dose is calculated using mean organ doses and tissue weighting factors. These findings will be compared to previously reported findings in standard settings and to conventional digital x-ray(CR)
Findings / Results: In AP position we found a mean liver organ dose of 0.03mSv as compared to 0.25mSv with standard dose settings, a significant dose reduction of 88%. As expected the liver dose was higher in PA position than AP position, 0.05mSv vs. 0.03mSv.
Conclusions: Preliminary results with micro-dose settings show a 88% reduction of organ dose and a theoretical reduction of radiation induced cancer. Previously a 35% effective dose reduction was reported for the EOS in standard settings compared to CR.
Simon Toftgaard Skov, Jan Hendrik Duedal Rölfing, Haisheng Li, Ebbe Stender Hansen, Cody Bünger
Orthopaedic Research Lab., Århus Universitetshospital; Orthopaedic Research Lab., Århus Universitetshospital; Orthopaedic dep., Århus Universitetshospital; Orthopaedic dep., Århus Universitetshospital; Orthopaedic dep., Århus Universitetshospital
Background: Wear and corrosion of metal implants are of great concern especially in MoM hip implants. Evidence of MoM wear in spinal implants in children is sparse.
Purpose / Aim of Study: To determine metal ion levels in children with cobalt-chromium/titanium GR undergoing interval lengthening.
Materials and Methods: Cross-sectional study in 34 patients including 8 children prior to surgery, median age 11.0 (range 3.3-15.8) were included during 1.7 years. Standardized venous blood samples were collected at median 2.6 (0-10) years post index surgery. Contamination-free consensus guidelines were followed. Blinded analysis was performed for serum chromium(Cr), cobalt(Co), molybdenum(Mo), titanium(Ti), aluminium(Al), vanadium(V) using high- resolution mass spectrometry at a certified laboratory.
Findings / Results: The Cr levels at index were median 1.9 ppb (0.5-10) vs. 1.1 ppb (0.5-80) during elongation, p=0.46. Cr levels exceeded the 7 ppb warning threshold given by MHRA (www.gov.uk) in 8 out of 34 children between 2.4-3.4 years post index surgery. All 8 Cr levels returned below threshold within the following year, despite presence of metal debris in most operated patients. Co levels increased from median 0.2 (0-0.4) ppb to 0.5 (0-2.6) ppb, p<0.0001. The median Ti levels at index was below the detection limit of 1 ppb (max 3.4) vs. 10.6 ppb (1.1-48.4) during elongation, p<0.001. Al, Mo, V levels did not differ.
Conclusions: 8 patients had transient Cr levels above the warning threshold. All returned below threshold within the next year. The children with elevated ion levels did not differ clinically from the remaining group. Minimizing and monitoring iatrogenic metal ion exposure in these children is important due to the increased risk of genotoxicity and mutagenicity. This study could not confirm an increased risk.
Orthopaedic Research Lab., Århus Universitetshospital; Orthopaedic Research Lab., Århus Universitetshospital; Orthopaedic dep., Århus Universitetshospital; Orthopaedic dep., Århus Universitetshospital; Orthopaedic dep., Århus Universitetshospital
Background: Wear and corrosion of metal implants are of great concern especially in MoM hip implants. Evidence of MoM wear in spinal implants in children is sparse.
Purpose / Aim of Study: To determine metal ion levels in children with cobalt-chromium/titanium GR undergoing interval lengthening.
Materials and Methods: Cross-sectional study in 34 patients including 8 children prior to surgery, median age 11.0 (range 3.3-15.8) were included during 1.7 years. Standardized venous blood samples were collected at median 2.6 (0-10) years post index surgery. Contamination-free consensus guidelines were followed. Blinded analysis was performed for serum chromium(Cr), cobalt(Co), molybdenum(Mo), titanium(Ti), aluminium(Al), vanadium(V) using high- resolution mass spectrometry at a certified laboratory.
Findings / Results: The Cr levels at index were median 1.9 ppb (0.5-10) vs. 1.1 ppb (0.5-80) during elongation, p=0.46. Cr levels exceeded the 7 ppb warning threshold given by MHRA (www.gov.uk) in 8 out of 34 children between 2.4-3.4 years post index surgery. All 8 Cr levels returned below threshold within the following year, despite presence of metal debris in most operated patients. Co levels increased from median 0.2 (0-0.4) ppb to 0.5 (0-2.6) ppb, p<0.0001. The median Ti levels at index was below the detection limit of 1 ppb (max 3.4) vs. 10.6 ppb (1.1-48.4) during elongation, p<0.001. Al, Mo, V levels did not differ.
Conclusions: 8 patients had transient Cr levels above the warning threshold. All returned below threshold within the next year. The children with elevated ion levels did not differ clinically from the remaining group. Minimizing and monitoring iatrogenic metal ion exposure in these children is important due to the increased risk of genotoxicity and mutagenicity. This study could not confirm an increased risk.