Influence of Selected Examination Postures on Shape of the Spine and Postural Stability in Humans

Abstract

Aims:The accuracy of non-radiographic measurement of the spinal shape is infl uenced by postural sway (PS). The aim of this study was to determine whether certain examination postures prevent PS without changing key spinal characteristics.Methods: We tested 1) natural standing position (posture A), 2) fi xation postures standing with the support of the upper limbs against a wall (posture B) and 3) standing with the support of the head and chest against a wall (posture C). There were examined 60 subjects; the examination of each posture was repeated fi ve times in each individual by DTP-3 microcomputer position system. The spinal shape changes resulting from tested postures were assessed using t-test. The role of PS was assessed using standard deviations, and the signifi cance of diff erences between the individual postures was determined using the F-test.Results: Compared to posture A, the fi xation posture B did not have any signifi cant infl uence on the degree of PS, but it signifi cantly infl uenced the shift of the spine from the ideal vertical and its slope, although this did not result in spine curve deformation. The fi xation posture C signifi cantly reduced the PS compared to posture A; however, there were signifi cant changes in the spinal shape. This fi xation posture shifted signifi cantly the spine from the ideal vertical and slope characteristics.Conclusion: PS plays a role in the examination of spinal shape. Positions B and C did not meet the required criteria. Therefore, it is necessary to search for another examination position.

Optimization of the examination posture in spinal curvature assessment

“…That is why we have begun to search for such measurement posture that could significantly reduce postural sway by means of mechanical fixation of the examined subject. In the previous study, we proposed and assessed the fixation procedures supporting the upper limbs against a wall (posture B) or supporting the chest against a wall (posture C) [15]. We discovered, however, that this type of fixation either does not bring about significant reduction in postural sway (posture B) or significantly influences the curvature of the spine (posture C).…”

“…For evaluating postural sway of each spinous process within the group of 70 subjects, examined in a selected posture, means of standard deviations MSD x MSD y MSD z were calculated as average values of standard deviations SD x SD y SD z in the entire group [15,17]. …”

“…Theoretically, precise spinal shape examination requires an examination posture that minimizes postural sway (random errors) and the changes in spinal shape (systematic errors). In our previous studies, we revealed that none of the tested postures complies entirely with the above-mentioned prerequisites [15,17]. Appropriate examination posture and standardization of positioning the subject in the course of examination enable mutual comparison of the results of examinations when performed using different methods, e.g.…”

“…However, any fixation procedure that reduces the size of postural sway may change the body position and the spinal shape simultaneously. It is obvious that in different examination postures the spinal shape may vary [15,16]. From the perspective of systematic errors at examination, it is important to deal with the question of the extent to which the spinal shape in examination postures with mechanical fixation resembles the spinal shape in free standing posture.…”

Validation of the DTP-3 System for Noninvasive Spinal Shape Measurement by Comparison with X-Ray Examination

“…neinvazivním vyšetření je úhlový parametr vypočten z křivky, která prochází koncovými body trnových výběžků, případně z plochy reliéfu kožního povrchu. Zdrojem neshod může být také různá standardizace vyšetřovací polohy, tedy jaké postavení zaujímá vyšetřovaná osoba v průběhu vyšetření (13,16). V neposlední řadě může rozdíly způsobovat systematická a náhodná chyba jednotlivých vyšetřovacích metod.…”