Kar Hao Teoh1,2, Abdul Nazeer Moideen3,4, Kausik Mukherjee5, Sridhar Kamath5, Stuart H James4, Alwyn Jones4, John Howes4, Paul R Davies4, Sashin Ahuja3,4. 1. School of Engineering, Cardiff University, Queen's Buildings, The Parade, Cardiff, CF24 3AA, UK. teohkh@cardiff.ac.uk. 2. Welsh Centre for Spinal Surgery and Trauma, University Hospital of Wales, Heath Park, Cardiff, CF14 4XW, UK. teohkh@cardiff.ac.uk. 3. School of Engineering, Cardiff University, Queen's Buildings, The Parade, Cardiff, CF24 3AA, UK. 4. Welsh Centre for Spinal Surgery and Trauma, University Hospital of Wales, Heath Park, Cardiff, CF14 4XW, UK. 5. Department of Radiology, University Hospital of Wales, Heath Park, Cardiff, CF14 4XW, UK.
Abstract
PURPOSE: Magnetic-controlled growing rods (MCGRs) are now routinely used in many centres to treat early-onset scoliosis (EOS). MCGR lengthening is done non-invasively by the external remote controller (ERC). Our experience suggests that there may be a discrepancy between the reported rod lengthening on the ERC and the actual rod lengthening. The aim of this study was to investigate this discrepancy. METHODS: This was a prospective series. Eleven patients who were already undergoing treatment for EOS using MCGRs were included in this study. RESULTS: One hundred and ninety-two sets of ultrasound readings were obtained (96 episodes of rod lengthening on dual-rod constructs) and compared to their ERC readings. Only 15/192 (7.8%) readings were accurate; 27 readings (14.9%) were false positive; and 8 readings (4.2%) were an underestimation while 142 readings (74.0%) were an overestimation by the ERC. Average over-reporting by the ERC was 5.31 times of the actual/ultrasound reading. When comparing interval radiographs with lengthening obtained on ultrasound, there was a discrepancy with an average overestimation of 1.35 times with ultrasound in our series. There was a significant difference between ERC and USS (p = 0.01) and ERC and XR (p = 0.001). However, there was no significant difference between USS and XR (p > 0.99). CONCLUSION: The reading on the ERC does not equate to the actual rod lengthening. The authors would recommend that clinicians using the MCGR for the treatment of early-onset scoliosis include pre- and post-extension imaging (radiographs or ultrasound) to confirm extension lengths at each outpatient extension. In centres with ultrasound facilities, we would suggest that patients should have ultrasound to monitor each lengthening after distraction but also 6-month radiographs. These slides can be retrieved under Electronic Supplementary Material.
PURPOSE: Magnetic-controlled growing rods (MCGRs) are now routinely used in many centres to treat early-onset scoliosis (EOS). MCGR lengthening is done non-invasively by the external remote controller (ERC). Our experience suggests that there may be a discrepancy between the reported rod lengthening on the ERC and the actual rod lengthening. The aim of this study was to investigate this discrepancy. METHODS: This was a prospective series. Eleven patients who were already undergoing treatment for EOS using MCGRs were included in this study. RESULTS: One hundred and ninety-two sets of ultrasound readings were obtained (96 episodes of rod lengthening on dual-rod constructs) and compared to their ERC readings. Only 15/192 (7.8%) readings were accurate; 27 readings (14.9%) were false positive; and 8 readings (4.2%) were an underestimation while 142 readings (74.0%) were an overestimation by the ERC. Average over-reporting by the ERC was 5.31 times of the actual/ultrasound reading. When comparing interval radiographs with lengthening obtained on ultrasound, there was a discrepancy with an average overestimation of 1.35 times with ultrasound in our series. There was a significant difference between ERC and USS (p = 0.01) and ERC and XR (p = 0.001). However, there was no significant difference between USS and XR (p > 0.99). CONCLUSION: The reading on the ERC does not equate to the actual rod lengthening. The authors would recommend that clinicians using the MCGR for the treatment of early-onset scoliosis include pre- and post-extension imaging (radiographs or ultrasound) to confirm extension lengths at each outpatient extension. In centres with ultrasound facilities, we would suggest that patients should have ultrasound to monitor each lengthening after distraction but also 6-month radiographs. These slides can be retrieved under Electronic Supplementary Material.
Authors: Jason P Y Cheung; Karen K L Yiu; Cora Bow; Prudence W H Cheung; Dino Samartzis; Kenneth M C Cheung Journal: Spine (Phila Pa 1976) Date: 2017-09-01 Impact factor: 3.468
Authors: Oliver M Stokes; Elizabeth J O'Donovan; Dino Samartzis; Cora H Bow; Keith D K Luk; Kenneth M C Cheung Journal: Spine J Date: 2014-01-31 Impact factor: 4.166
Authors: Kar H Teoh; Daniel M G Winson; Stuart H James; Alwyn Jones; John Howes; Paul R Davies; Sashin Ahuja Journal: Spine J Date: 2016-02-02 Impact factor: 4.166