Validity of a one-item drawing-based instrument to assess trunk deformity perception in kyphotic deformities.

ABSTRACT

INTRODUCTION: Body image and trunk appearance perception are two crucial attributes in determining the quality of life of individuals with spinal deformities. The Trunk Appearance Perception Scale (TAPS) is a drawing-based instrument used to evaluate this feature. The TAPS does not include a sagittal view of the trunk so it is never been used to assess trunk deformity perception in hyperkyphotic patients. This study aims to analyze the effect of introducing a new drawing on the TAPS scale representing the trunk view in the sagittal plane. PATIENTS 170 non-surgical patients were included (mean age 16.9 years and 77.4% women) distributed in three groups. CONTROL group (no deformity) 22 cases; KYPHOSIS group (sagittal deformity) 49 cases and SCOLIOSIS group (coronal deformity) 99 cases (mean Cobb 42.4º). METHOD: Cross-sectional study. A new drawing (TAPS4) was designed to represent the deformity in the sagittal plane with five response options. Clinical (SRS-22 and TAPS 4-items) and radiological (kyphosis T4-T12) data were collected in all patients. The statistical analysis consisted in determining for each group the internal consistency of the 3-items TAPS vs 4-items TAPS, as well as the discriminant validity (correlation with kyphosis magnitude) and convergent validity (correlation with the SRS-22 image subscale). In addition, test-retest reliability of new item 4 was determined in a subgroup of 30 kyphotic patients. During control visit, the patients received a complete physical examination and a full-spine AP and lateral X-ray in standing position using a low-radiation technique and fulfilled instruments TAPS 4 items and SRS-22r. RESULTS: The three groups were found to have statistically significant differences in the magnitude of kyphosis, quality of life, body image perception, the 3-items TAPS, 4-items TAPS and new item 4 score. The addition of the item 4 to TAPS 3 items did not cause a significant change in the internal consistency of the scales (Cronbach's alpha) (TAPS 3-items 0.8 vs. TAPS 4-items 0.8). Kyphosis magnitude was not correlated with the 3-items TAPS and 4-items TAPS scores; however, in the KYPHOSIS group, a significant negative correlation was observed between kyphosis and item 4 (Rho = - 0.4, p = 0.0001). A significant correlation was found in all groups between TAPS 3-items and TAPS 4-items and SRS-22 image domain; the correlation between item 4 and SRS-22 body image domain was 0.3 in the Scoliosis group and 0.7 in the Kyphosis group. CONCLUSIONS: The 4-items TAPS scale does not provide advantages in the assessment of trunk deformity over the 3-items scale. However, in patients with kyphosis, the item 4 (Kypho-TAPS) alone is a valid and reliable instrument to monitor the perception of the trunk deformity.