The Reliability and In-exercise Reduction of Frontal and Rotational Ultrasound Measurements for Adolescents with Idiopathic Scoliosis Performing Scoliosis-specific Exercises

  • Author / Creator
    Su, Alex
  • Adolescent Idiopathic Scoliosis (AIS) is a spine deformity of unknown cause characterized by abnormal lateral curvature (Cobb angle>10°) with vertebral rotation. AIS affects 2-3% of all adolescents whom are likely to progress during their growth spurt preceding skeletal maturity. The Scoliosis Research Society (SRS) has recognized that physiotherapeutic scoliosis-specific exercises (PSSE) may benefit individuals with AIS. These benefits include slowing curve progression and improved pain management, self-image, strength, and endurance. However, how these PSSEs achieve their effects and which instructions provide the best spinal corrections are still unknown. Skepticism from stakeholders exist about the feasibility of these complex exercises achieving clinically meaningful corrections without compensation. A novel 3D ultrasound (US) imaging protocol can non-invasively quantify spinal alignment which allows investigation of the immediate effects of PSSE in an ethical manner. This could lead to improved exercise instruction and identifying which exercises offer the best corrections for patients. Recently, it was found that immediate in-brace correction is predictive of treatment success and identifying the immediate amount of correction achieved in PSSE is necessary to study if this may also be true for PSSE treatment outcomes. Lastly, apical vertebral translation (AVT), has long been a neglected measurement in PSSE research even though it is an important surgical decision-making measurement for AIS. This project used US imaging to quantify the immediate effects of Schroth PSSE on the thoracic and lumbar curve angle, axial vertebral rotation (AVR), and AVT measurements in 16 different positions. The intra- and inter-evaluator reliability of these US measurements were also determined. In a single session, 16 different positions, comprised of four habitual positions and their passive and active Schroth corrections, were imaged using 3D US imaging. Thirty-six volunteers were recruited after having completed three or more months of Schroth exercise. Selection criteria were: females aged 10 to 18 years old with AIS, with or without a brace, a Cobb angle of 10° to 45° for both a lumbar, and a thoracic, or thoraco-lumbar curve, and no prior surgery. Custom MATLAB software was used to measure each scan. Images were analyzed using the center of lamina (COL) method. Thoracic and lumbar curve angles were extracted along with the AVR of the levels above, at, and below the apices. Thoracic and lumbar AVR and AVT measurement differences were used to calculate the max AVR twist and interapical distance. Intra-evaluator reliability was determined from 13 participants’ scans measured by a blinded evaluator. Inter-evaluator reliability was determined from 35 participants; scans measured by two evaluators. Intraclass correlation coefficients (ICC’s) were reported along with standard error of measurement (SEM). Repeated measures ANOVAs were used to compare positions with Sidak pairwise comparison analysis. Results: The intra and inter-evaluator reliability of the thoracic and lumbar curve angles, AVR, max AVR twist, AVT, and interapical distance measurements were adequate for research (ICC>0.70). Reliability estimates were lower than previous studies testing in standing or lying, but SEM values were still within accepted thresholds. The novel AVT measurements were among the most reliable measurements across all positions. The mean age of the participants was 15±3 years old with mean thoracic and lumbar curve angles of 16±8° and 18±9°, respectively. All measurements were largest in habitual standing. The lowest thoracic and lumbar curve angles, AVT, and interapical distance was observed in the sitting active exercise with hip flexion. The lowest max AVR twist was in the prone active exercise with hip flexion. The lumbar curve angle in the final repeated standing was significantly reduced compared to habitual standing indicating residual effects from a single exercise session. In conclusion, US imaging produces reliable measurements of the thoracic and lumbar curve angles, AVR, max AVR twist, AVT, and interapical distance and can be used to assess the spine in a variety of positions. Comparisons indicated that Schroth exercises produce the greatest corrections for patients, regardless of habitual position. The largest reduction was produced by active correction by the participant without compensatory change elsewhere. Therefore, Schroth exercises create immediate clinically significant corrections to the frontal and rotational profile of AIS. These research findings may help inform clinicians and therapists about the feasibility of achieving corrections from PSSE and influence their instruction. Schroth exercises may provide lasting corrections with unknown duration.

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  • Degree
    Master of Science
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