Evaluation of rasterstereographic examinations in postsurgical adolescent scoliosis patients: a reliability study. To investigate the interobserver and intraobserver reliability of rasterstereographic 3-dimensional back surface analysis and reconstruction of spine parameters including trunk length, trunk inclination, lateral deviation, kyphotic and lordotic angles in adolescent idiopathic scoliosis patients after scoliosis surgery. The rasterstereography device formetric III 4D has been in routine clinical use for patients with scoliosis and other spinal deformities, reducing the patients' radiation exposure considerably. The reliability of this device has previously been examined in healthy volunteers but not in patients after scoliosis surgery. Thirty-nine adolescent idiopathic scoliosis patients (32 women and 7 men) after scoliosis surgery with a mean age of 23.5 years (±10.6 y) were examined rasterstereographically by 5 investigators. Each investigator made a series of 3 measurements of each participating patient consecutively. The intraclass correlation coefficient (ICC) and the Pearson product moment correlation were calculated. In addition, the comparative analysis of the first and 15th measurements was assessed. The ICCs of all investigated parameters demonstrated very high interobserver and intraobserver reliability. The maximum ICC (0.988) for interobserver reliability of the 5 investigators was found for the trunk length and the minimum ICC (0.918) for lateral deviation. There were highly significant positive correlations between the first, second, and third measurements (r=0.994-0.697; P<0.001) for intraobserver reliability. Overall highly significant correlation was found comparing the results of the first and the 15th rasterstereographic measurement. The reliability of rasterstereography formetric III 4D in regard to the investigated parameters is excellent. The device can be used very efficiently by 1 or multiple investigators to analyze postsurgical adolescent idiopathic scoliosis patients in clinical practice, requiring only a single investigational exposure.