Interobserver Reliability and Intraobserver Reproducibility of the System of King et al. for the Classification of Adolescent Idiopathic Scoliosis*

Cummings, R. Jay; Loveless, Eric A.; Campbell, Joan E.; Samelson, S; Mazur, John M.

doi:10.2106/00004623-199808000-00003

Cited by 129 publications

(54 citation statements)

References 10 publications

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“…This is reflected by current controversies in the literature regarding the definition of a structural upper thoracic [20,21,42,44] or lumbar curve [19,21,34,36]. We suspect that part of the disagreement can also be explained by the well documented inter-observer variability of current surgical classification systems [8,22,24,35]. However, as the surgeons were not asked to report which curve classification they were using and to classify each case with either using the King [18] or Lenke [24] system, it is not possible to confirm the effect of curve classification in the current study.…”

Section: Discussionmentioning

confidence: 99%

Variability of spinal instrumentation configurations in adolescent idiopathic scoliosis

2006

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Surgical instrumentation for the correction of adolescent idiopathic scoliosis (AIS) is a complex procedure involving many difficult decisions (i.e. spinal segment to instrument, type/location/number of hooks or screws, rod diameter/ length/shape, implant attachment order, amount of rod rotation, etc.). Recent advances in instrumentation technology have brought a large increase in the number of options. Despite numerous clinical publications, there is still no consensus on the optimal surgical plan for each curve type. The objective of this study was to document and analyse instrumentation configuration and strategy variability. Five females (12-19 years) with AIS and an indication for posterior surgical instrumentation and fusion were selected. Curve patterns were as follows: two right thoracic (Cobb: 34°, 52°), two right thoracic and left lumbar (Cobb T/L: 57°/45°, 72°/70°) and 1 left thoraco-lumbar (Cobb: 64°). The pre-operative standing posteroanterior and lateral radiographs, supine side bending radiographs, a three-dimensional (3D) reconstruction of the spine, pertinent 3D measurements as well as clinical information such as age and gender of each patient were submitted to six experienced independent spinal deformity surgeons, who were asked to provide their preferred surgical planning using a posterior spinal approach. The following data were recorded using the graphical user interface of a spine surgery simulator (6·5 cases): implant types, vertebral level, position and 3D orientation of implants, anterior release levels, rod diameter and shape, attachment sequence, rod rotation (angle, direction), adjustments (screw rotation, contraction/distraction), etc. Overall, the number of implants used ranged from 11 to 26 per patient (average 16; SD ±4). Of these, 45% were mono-axial screws, 31% multi-axial screws and 24% hooks. At one extremity of the spectrum, one surgeon used only mono-axial screws, while at the other, another surgeon used 81% hooks. The selected superior-and inferior-instrumented vertebrae varied up to six and five levels, respectively (STD 1.2 and 1.5). A top-tobottom attachment sequence was selected in 61% of the cases, a bottom-up in 29% and an alternate order in 11%. The rod rotation maneuver of the first rod varied from 0°(no rotation) to 140°, with a median at 90°. In conclusion, a large variability of instrumentation strategy in AIS was documented within a small experienced group of spinal deformity surgeons. The exact cause of this large variability is unclear but warrants further investigation with multicenter outcome studies as well as experimental and computer simulation studies. We hypothesize that Eur Spine J (2007) 16: 57-64

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Section: Discussionmentioning

confidence: 99%

Variability of spinal instrumentation configurations in adolescent idiopathic scoliosis

2006

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“…10 The Lenke classification system that uses measurements in both coronal and sagittal planes was introduced in 1997, and has reasonably good reproducibility rating [11][12][13][14][15] as compared with the King classification system. 16 It is now used extensively and continues to be further developed with the addition of new indices such as the deformity score or the LenkeHarms score. 17 Although the King classification primarily focused on thoracic curves, the Lenke classification approaches the issue in a more global sense by proposing a generic classification scheme that also considers the thoracolumbar/lumbar (TL/L) curves.…”

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confidence: 99%

Three-Dimensional Classification of Thoracic Scoliotic Curves

Sangole¹,

Aubin²,

Stokes³

et al. 2009

Spine

107

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Study Design. Three-dimensional (3D) characterization of the thoracic scoliotic spine (cross-sectional study).Objectives. To investigate the presence of subgroups within Lenke type-1 curves by evaluating the thoracic segment indices extracted from 3D reconstructions of the spine, and to propose a new clinically relevant means (the daVinci representation) to report 3D spinal deformities.Summary of Background Data. Although scoliosis is recognized to be a 3D deformity of the spine its measurement and classification have predominantly been based on radiographs which are 2D projections in the coronal and sagittal planes.Methods. Thoracic segment indices derived from 3D reconstructions of coronal and sagittal standing radiographs of 172 patients with right thoracic adolescent idiopathic scoliosis, reviewed by the 3D Classification Committee of the Scoliosis Research Society, were analyzed using the ISOData unsupervised clustering algorithm. Four curve indices were analyzed: Cobb angle, axial rotation of the apical vertebrae, orientation of the plane of maximum curvature of the main thoracic curve, and kyphosis (T4 -T12). No assumptions were made regarding grouping tendencies in the data nor were the number of clusters predefined.Results. Three primary groups were revealed wherein kyphosis and the orientation of the PMC of the main thoracic curve were the major discriminating factors with slight overlap between groups. A small group (G1) of 22 patients having smaller, nonsurgical (minor) curves was identified. Although the remaining patients had similar Cobb angles they were split into 2 groups (G2: 79 patients; G3: 71 patients) with different PMC (G2: 65°-81°; G3: 76°-104°) and kyphotic measures (G2: 23°-43°; G3: 7°-25°). Conclusion.Two distinct subgroups within the surgical cases (major curves) of Lenke type-1 curves were found thus suggesting that thoracic curves are not always hypokyphotic. The ISOData cluster analysis technique helped to capture inherent 3D structural curve complexities that were not evident in a 2D radiographic plane. The daVinci representation is a new clinically relevant means to report 3D spinal deformities.

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“…Poor reliability of the King classification was shown in previous studies [3,4]. Since it relies on subjective measurement and classification, there are high chance of intraobserver and interobserver variability.…”

Section: Discussionmentioning

confidence: 89%

“…Since the King classification relies on the subjective curve measurement and the interpretation of classification criteria, its reliability is an issue to be concerned. The reported empirical studies on repeat classification by the King method showed poor reliability [3,4].…”

Section: Introductionmentioning

confidence: 99%

Computer-aided King classification of scoliosis

Zhang

et al. 2015

THC

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Abstract. OBJECTIVE: Surgical planning for scoliosis relies on the classification of spinal curve pattern. The widely used King classification is subject to human measurement and judgment errors. To reduce the variability of King classification, a computer-aided method is proposed and its reliability is evaluated in this study. METHODS: At the first step, endplate inclination and position of each vertebra are measured by a computerized system on the posteroanterior radiograph. Based on these measurements, the apical and end vertebrae are identified and then the Cobb angles are calculated automatically. The system subsequently classifies the curve types automatically based on the computerized Cobb measurements, the vertebral inclination, and the analysis of the relationship between the center sacral vertical line, and the apical lumbar vertebra. Five observers participated in the experiments. The kappa statistic was used to evaluate the variability. RESULTS: Classifications of 105 scoliotic cases by the five observers showed that with the aid of our system, the average intraobserver and interobserver kappa values improved from 0.75 to 0.90 and from 0.66 to 0.86, respectively. CONCLUSION: Results indicate that the proposed computerized system can assist a surgeon with the King classification of scoliosis.

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Interobserver Reliability and Intraobserver Reproducibility of the System of King et al. for the Classification of Adolescent Idiopathic Scoliosis*

Cited by 129 publications

References 10 publications

Variability of spinal instrumentation configurations in adolescent idiopathic scoliosis

Variability of spinal instrumentation configurations in adolescent idiopathic scoliosis

Three-Dimensional Classification of Thoracic Scoliotic Curves

Computer-aided King classification of scoliosis

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