Ricarda Lechner

Interrater and intrarater reliability of the Kuntz et al new deformity classification system.

BACKGROUND Kuntz et al recently introduced a new system for classifying spinal deformities. This classification of spinal deformity was developed from age-dependent deviations from the neutral upright spinal alignment. OBJECTIVE To determine the interobserver and intraobserver reliabilities of the new Kuntz et al system for classifying scoliosis. METHODS Fifty consecutive patients were evaluated. Three observers independently assigned a major structural curve, minor structural curve, curve type, apical vertebral rotation, spinal balance, and pelvic alignment to each curve following the guidelines described by Kuntz et al. Assignment of the curves was repeated 4 weeks later, with the curves presented in a different blinded order. The Kendall W and Holsti agreement coefficients were used to determine the interobserver and intraobserver agreement. RESULTS The intraobserver value of agreement for all parameters was 0.85 (range, 0.28-1.0), and the mean Kendall W coefficient was 0.89 (range, 0.5-0.97), demonstrating perfect reliability. The interobserver agreement averaged 0.7 (range, 0.251-1.0). The mean Kendall W coefficient was 0.67 (range, 0.19-1.0), demonstrating substantial reliability. The average time for classification of 1 curve was approximately 8.4 minutes. CONCLUSION The new Kuntz et al deformity classification system is comparable to the Lenke et al system in terms of reliability. However, the Kuntz et al classification system provides no recommendations for surgical interventions. It is more complex and time-consuming and therefore may be of limited value in daily clinical practice.

Inter- and intraobserver reliability assessment of computed tomographic 3D measurement of pedicles in scoliosis and size matching with pedicle screws

BackgroundIn patients with scoliosis, the morphology of the pedicles differs from those in normal spines. Preoperative three-dimensional information of these complex anatomic situations means a great advantage for the surgeon in order to assess which pedicles can be instrumented safely avoiding screw misplacement and for the decisions in choosing the appropriate screw size. The objective of this study was to measure pedicle dimensions in scoliotic spines on three-dimensional computed tomographic (CT) scans and to determine the intra- and interobserver reliability of the method. Additionally, the pedicles that cannot be instrumented safely by available screws were identified. MethodsAll pedicles from T1 to L5 in 30 patients with scoliosis were measured by two independent observers. The pedicle width, height and length were assessed for two times with a 3-week interval. Intraclass correlation coefficients were used to determine the intra- and interobserver reliabilities. The diameters of the pedicles were matched with the dimensions of the smallest available pedicle screws of scoliosis implant systems.Results The intrarater reliability was strong in 60% of the parameters and moderate in 40%. The interrater reliability was strong in all parameters but in pedicle length. The concave-sided pedicles in the curve revealed to be smaller compared to the convex-sided ones. The highest percentage of size mismatch was found in levels T7 (31%) and T8 (33%). ConclusionsMeasurement of pedicle dimensions on three-dimensional CT scans is a reliable but time-consuming procedure to assess pedicle dimensions. CT measuring should be reserved for special cases, where the anatomic situation remains unclear despite X-ray. In scoliotic spines, one-third of the mid-thoracic pedicles cannot be instrumented safely with pedicle screws.

Comparison of two- and three-dimensional measurement of the Cobb angle in scoliosis

PurposeThe Cobb angle as an objective measure is used to determine the progression of deformity, and is the basis in the planning of conservative and surgical treatment. However, studies have shown that the Cobb angle has two limitations: an inter- and intraobserver variability of the measurement is approximately 3–5 degrees, and high variability regarding the definition of the end vertebra. Scoliosis is a three-dimensional (3D) pathology, and 3D pathologies cannot be completely assessed by two-dimensional (2D) methods, like 2D radiography. The objective of this study was to determine the intraobserver and interobserver reliability of end vertebra definition and Cobb angle measurement using X-rays and 3D computer tomography (CT) reconstructions in scoliotic spines.MethodsTo assess interoberver variation the Cobb angle and the end vertebra were assessed by five observers in 55 patients using X-rays and 3D CT reconstructions. Definition of end vertebra and measurement of the Cobb angle was repeated two times with a three-week interval. Intraclass correlation coefficients (ICC) were used to determine the interobserver and intraobserver reliabilities. 95% prediction limits were provided for measurement errors.ResultsIntraclass correlation coefficient (ICC) showed excellent reliability for both methods. The measured Cobb angle was on average 9.2 degrees larger in the 3D CT group (72.8°, range 30–144) than on 2D radiography (63.6°, range 24–152).ConclusionsIn scoliosis treatment it is very essential to determine the curve magnitude, which is larger in a 3D measurement compared to 2D radiography.

Two-year gait analysis controls of the minimally invasive total hip arthroplasty by the direct anterior approach

Background: The purpose of the study was to determine the long‐term functional outcome of two hip approaches by gait analysis. Patients were selected by prospective randomization, and operated on either by the anterolateral approach or by a minimally invasive direct anterior approach. Methods: 33 patients (17 anterolateral approach; 16 direct anterior approach) were analyzed using a Vicon 870 system. Gait analysis was performed two years after total hip arthroplasty. Temporo‐spatial and kinematic variables were obtained. Findings: On chest and pelvic kinematics, no patient group demonstrated significant differences. The time‐distance parameters showed significant differences with the anterior approach in cadence and stride time. Interpretation: The study indicates that the direct anterior approach exerts positive effects compared with the anterolateral approach two years after surgery. The muscle‐sparing concept of direct anterior approach results in significant differences in gait compared to the anterolateral approach 2 years after surgery. HighlightsDirect anterior approach significantly better in cadence, step time and stride timeKinematics for the thorax and pelvis showed no significant difference.Patient reported outcome measures showed no significant difference.