caa a22 4500 445831332 CHVBK 20180317145316.0 cr unu---uuuuu 170323e20110101xx s 000 0 eng 10.1007/s00586-010-1534-3 doi (NATIONALLICENCE)springer-10.1007/s00586-010-1534-3 The "X-Factor” Index: a new parameter for the assessment of adolescent idiopathic scoliosis correction [Elektronische Daten] [Yu Sun, Dino Samartzis, Kenneth Cheung, Yat Wong, Keith Luk] The correction rate (CR) and fulcrum bending correction index (FBCI) based on the fulcrum bending radiograph (FBR) were parameters introduced to measure the curve correcting ability; however, such parameters do not account for contributions by various, potential extraneous "X-Factors” (e.g. surgical technique, type and power of the instrumentation, anesthetic technique, etc.) involved in curve correction. As such, the purpose of the following study was to propose the concept of the "X-Factor Index” (XFI) as a new parameter for the assessment of the correcting ability of adolescent idiopathic scoliosis (AIS). A historical cohort radiographic analysis of the FBR in the setting of hook systems in AIS patients (Luk et al. in Spine 23:2303-2307, 1998) was performed to illustrate the concept of XFI. Thirty-five patients with AIS of the thoracic spine undergoing surgical correction were involved in the analysis. Plain posteroanterior (PA) plain radiographs were utilized and Cobb angles were obtained for each patient. Pre- and postoperative PA angles on standing radiograph and preoperative fulcrum bending angles were obtained for each patient. The fulcrum flexibility, curve CR, and FBCI were determined for all patients. The difference between the preoperative fulcrum bending angle and postoperative PA angle was defined as AngleXF, which accounted for the correction contributed by "X-Factors”. The XFI, designed to measure the curve correcting ability, was calculated by dividing AngleXF by the fulcrum flexibility. The XFI was compared with the curve CR and FBCI by re-evaluating the original data in the original paper (Luk et al. in Spine 23:2303-2307, 1998). The mean standing PA and FBR alignments of the main thoracic curve were 58.3° and 24.5°, respectively. The mean fulcrum flexibility was 58.8%. The mean postoperative standing PA alignment was 24.7°. The mean curve CR was 58.0% and the mean FBCI was 101.1%. The mean XFI was noted as 1.03%. The CR was significantly positively correlated to curve flexibility (r=0.66; p<0.01).The FBCI (r=−0.47; p=0.005) and the XFI (r=−0.45; p=0.007) were significantly negatively correlated to curve flexibility. The CR was not correlated to AngleXF (r=0.29; p=0.089).The FBCI (r=0.97; p<0.01) and the XFI (r=0.961; p<0.01) were significantly positively correlated to AngleXF. Variation in XFI was noted in some cases originally presenting with same FBCI values. The XFI attempts to quantify the curve correcting ability as contributed by "X-Factors” in the treatment of thoracic AIS. This index may be a valued added parameter to accompany the FBCI for comparing curve correction ability among different series of patients, instrumentation, and surgeons. It is recommended that the XFI should be used to document curve correction, compare between different techniques, and used to improve curve correction for the patient. Springer-Verlag, 2010 Scoliosis nationallicence Fulcrum bending nationallicence Radiograph nationallicence Flexibility nationallicence Curve nationallicence Correction nationallicence Rate nationallicence Index nationallicence X-Factor nationallicence AIS : Adolescent idiopathic scoliosis nationallicence FBR : Fulcrum bending radiograph nationallicence CR : Correction rate nationallicence FBCI : Fulcrum bending correction index nationallicence XFI : X-Factor Index nationallicence AngleTC : The angle of total correction nationallicence AngleF : The correction angle contributed by the inherent flexibility of the curve nationallicence AngleXF : The correction angle contributed by "X-Factors” nationallicence Sun Yu Department of Spine, Beijing Ji Shui Tan Hospital, Xinjiekou East Street 31, Xicheng District, 100035, Beijing, People's Republic of China aut Samartzis Dino Department of Orthopaedics and Traumatology, The University of Hong Kong, Queen Mary Hospital, Professorial Block, 5th Floor, 102 Pokfulam Road, Pokfulam, Hong Kong SAR, China aut Cheung Kenneth Department of Orthopaedics and Traumatology, The University of Hong Kong, Queen Mary Hospital, Professorial Block, 5th Floor, 102 Pokfulam Road, Pokfulam, Hong Kong SAR, China aut Wong Yat Department of Orthopaedics and Traumatology, The University of Hong Kong, Queen Mary Hospital, Professorial Block, 5th Floor, 102 Pokfulam Road, Pokfulam, Hong Kong SAR, China aut Luk Keith Department of Orthopaedics and Traumatology, The University of Hong Kong, Queen Mary Hospital, Professorial Block, 5th Floor, 102 Pokfulam Road, Pokfulam, Hong Kong SAR, China aut European Spine Journal Springer-Verlag 20/1(2011-01-01), 144-150 0940-6719 20:1<144 2011 20 586 https://doi.org/10.1007/s00586-010-1534-3 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00586-010-1534-3 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Sun Yu Department of Spine, Beijing Ji Shui Tan Hospital, Xinjiekou East Street 31, Xicheng District, 100035, Beijing, People's Republic of China aut NATIONALLICENCE 700 1- Samartzis Dino Department of Orthopaedics and Traumatology, The University of Hong Kong, Queen Mary Hospital, Professorial Block, 5th Floor, 102 Pokfulam Road, Pokfulam, Hong Kong SAR, China aut NATIONALLICENCE 700 1- Cheung Kenneth Department of Orthopaedics and Traumatology, The University of Hong Kong, Queen Mary Hospital, Professorial Block, 5th Floor, 102 Pokfulam Road, Pokfulam, Hong Kong SAR, China aut NATIONALLICENCE 700 1- Wong Yat Department of Orthopaedics and Traumatology, The University of Hong Kong, Queen Mary Hospital, Professorial Block, 5th Floor, 102 Pokfulam Road, Pokfulam, Hong Kong SAR, China aut NATIONALLICENCE 700 1- Luk Keith Department of Orthopaedics and Traumatology, The University of Hong Kong, Queen Mary Hospital, Professorial Block, 5th Floor, 102 Pokfulam Road, Pokfulam, Hong Kong SAR, China aut NATIONALLICENCE 773 0- European Spine Journal Springer-Verlag 20/1(2011-01-01), 144-150 0940-6719 20:1<144 2011 20 586 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer