Reliability and Effect of Arm Positions Used During Imaging on Spinal Alignment Parameters in Healthy and Adolescent Idiopathic Scoliosis Populations
Creators: Fehr, Brianna
Publisher: name: University of Alberta Library
Year: 2024

<p>Adolescent idiopathic scoliosis (AIS) is a 3D spine disorder with lateral curvature, vertebral rotation, and sagittal changes. AIS affects 2-3% of the adolescent population. Adolescents with progressive idiopathic scoliosis receive numerous x-rays throughout their treatment, exposing them to harmful radiation throughout growing years. Particularly in young children, increased exposure to radiation has been shown to increase the incidence of cancer. Clinicians detect progression in frontal curves using radiographs around every 6 months during growth, and with new low-dose imaging technology, the arms must be elevated when capturing the sagittal view to visualize the vertebrae. Raising the arms has been shown to affect spinal sagittal angles. It is unclear which arm positions minimize the effects on spinal alignment measurements and which are the closest representatives of the habitual posture. Additionally, it is unknown whether such positions could allow scoring skeletal maturity which require hand exposure possibly above the shoulders. 3D Ultrasound (3DUS) is a safe method to assess arm positions without any radiation exposure.<br>
This study aimed to, foremost, synthesize and review the literature on this topic. Additionally, this study aimed to determine the test-retest reliability of 3DUS imaging results in three standing positions; find a standing posture used to acquire simultaneous frontal and lateral radiographs that best equate to habitual standing posture; and to identify whether any of the arm positions that minimize spinal alignment changes could allow for skeletal maturity assessment.<br>
To test if different arm positions change spinal alignment in volunteers with and without AIS, 3DUS was used to measure the angle of vertebral rotation (AVR), frontal, and sagittal curve angles in ten different positions: 1)habitual standing, 2) arms supported at 60o of shoulder flexion (local EOS positioning), 3) fingers to clavicles, 4) fingers to chin, 5) fingers to zygomatic, 6) fingers to eyebrows, 7) shoulders abducted 90o hands open with thumb on shoulder, 8) hands on wall, 9) hands on block, and 10) hands unsupported. Three positions (1,3,8) were re-tested for reliability analysis. Separate group by position mixed model ANOVAs compared the effect of arm positions among groups. Separate repeated measures ANOVA explored the comparison of the effect of the 10 positions among male participants.<br>
Our systematic review screened 1332 abstracts and 33 full texts. Data was extracted from 7 studies. Common positions were habitual standing, fists on clavicle, and active (arms raised unsupported). Kyphosis, lordosis, and sagittal vertical axis (SVA) were most measured. Meta- analysis showed significantly decreased kyphosis (SMD= 0.8o, 95%CI= 0.5,1.1) and increased lordosis (SMD= -1.2o, 95%CI= -1.6,-0.9) when clavicle was compared to standing. Significant posterior shifts in SVA were shown in clavicle compared to standing (MD= 30.6mm, 95%CI= 23.9,37.3) and active compared to clavicle (MD= -2.0mm, 95%CI= -3.4,-0.6). Frontal and transverse parameters were rarely studied (1 study).<br>
Reliability (ICC3,1) with standard error of measurement (SEM) was calculated for test- retest acquisition and measurements by one evaluator blinded to the test measurement when completing the retest in 43 females and males with AIS. Reliability of frontal and sagittal parameters in the three positions were adequate for research use (ICC&gt;0.70). AVR measurements and all measurements in the hands on wall position were most reliable and adequate for individual use (ICC&gt;0.90).<br>
Ninety females with and without AIS with mean age, height, and weight of 17±4years, 162±6cm, and 55±10kg, and ten males with AIS (16±3 years, 174±11 cm, and 63±13 kg), were included for comparison of arm positions. Maximum curve angle showed group by position interactions. Female with AIS single-curve showed larger curves in standing in all positions excluding hands on blocks (p&gt;0.05). Sagittal parameters did not show group by position interactions, but position pairwise comparisons showed decreases in kyphosis in arms abducted 90o and increases in lordosis in fingers to cheeks/eyebrows (p&gt;0.05). AVR twist was not significantly affected by changes in position. Males with AIS showed comparable results to females, but no significant differences were detected.<br>
Overall, US imaging produces reliable measurements for frontal, sagittal, and transverse spinal parameters in common standing positions. Arm position comparisons show there is not one position representative of habitual standing posture for all group compared. None of the positions that expose the hands fully represent standing among all groups. When arms are raised, decreases in max curve angle were shown in those with single-curves, and decreases in kyphosis and increases in lordosis were found for all groups. These findings may inform clinicians which arm positions are best to adopt when capturing frontal and sagittal radiograph images.</p>