Implant Density and Curve Correction Rate in Scoliosis Surgery Using a 3 D Based Correction Strategy
Refereed conference paper presented and published in conference proceedings


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AbstractIntroduction: Adolescent Idiopathic Scoliosis (AIS) is a three dimensional deformity. The pedicle screw (PS) instrumentation and 3D correction strategy is currently the method to arrests progression and restore normal 3D alignment of the spine to provide a long lasting functional spine. Implant density and location has been a controversial issue in relation to curve correction. This paper aims to analyse the relationship between implant density and curve correction rate.

Methodology: We review AIS patients who had undergone Posterior Spinal Fusion from 2014 to 2017. Pre- operative standing, side bend (SB), fulcrum bend (FB) and post operative Cobb angles were analysed to determine the relationship between implant density, curve flexibility and correction rates. The sagittal alignment was also analysed in these patients.

Results and Analysis: There are 33 patients with 25 female and 8 male. Pre –operative Cobb angle was 73° +/- 19 ( 49-102°) , Side bend correction was 27+/- 14%, fulcrum bend correction was 46+/-17%, and operative correction was 66+/-12%, Fulcrum Bend Correction index ( FBCI) was 157+/- 47% (86-259). The implant density was 76+/-14% (55-100). The Fulcrum Bend flexibility is lower in high magnitude curves. The operative correction rate is correlated to FBCI. There is a weak correlation between implant density and operative correction rate. The FBCI was inversely related to the implant density. Implant density below 70 % there is a weak correlation between implant density and correction rate and there is no correlation when density was above 70%. A sub-group analysis of 7 rigid cases FB correction less than 30%, the higher density index has a better curve correction but the number of cases were small.

Discussion and Conclusion: In this small study with detailed analysis of intrinsic flexibility of the scoliosis, it showed that in flexible curves there is no advantage in having high density implant (>70%) as the correction plateau out. There may be some evidence that in rigid cases, higher implant gave a better correction rate. Further study is required to study the high angle and rigid cases and also to study other factors such as BMI, age and bone quality by Dexa scan.
All Author(s) ListBKW Ng, VC Illescas, JWC Chau, JCY Cheng
Name of ConferenceHong Kong Orthopaedic Association 38th Annual Congress 2018 (HKOA 2018)
Start Date of Conference03/11/2018
End Date of Conference04/11/2018
Place of ConferenceHong Kong
Country/Region of ConferenceHong Kong
Proceedings TitleThe Proceedings of Hong Kong Orthopaedic Association 38th Annual Congress 2018 (HKOA 2018)
Year2018
Month11
Place of PublicationHong Kong
Pages77 - 77
LanguagesEnglish-United Kingdom

Last updated on 2019-24-04 at 12:17