Introduction of the Novel Radiographic Line (L5-Kyphosis Apex Line) Intended to Evaluate Scheuermann's Disease and Postural Kyphosis Progression on Standard Lateral X-Rays

Loss of CSF-contacting neuron sensory function is associated with a hyper-kyphosis of the spine reminiscent of Scheuermann's disease

Scheuermann's disease, also referred to as Scheuermann's kyphosis, is the second most frequent spine deformity occurring in humans after adolescent idiopathic scoliosis (AIS), both with an unclear etiology. Recent genetic studies in zebrafish unraveled new mechanisms linked to AIS, highlighting the role of the Reissner fiber, an acellular polymer bathing in the cerebrospinal fluid (CSF) in close proximity with ciliated cells and mechanosensory neurons lining the central canal of the spinal cord (CSF-cNs). However, while the Reissner fiber and ciliary beating have been linked to AIS-like phenotypes in zebrafish, the relevance of the sensory functions of CSF-cNs for human spine disorders remains unknown. Here, we show that the thoracic hyper-kyphosis of the spine previously reported in adult pkd2l1 mutant zebrafish, in which the mechanosensory function of CSF-cNs is likely defective, is restricted to the sagittal plane and is not associated with vertebral malformations. By applying orthopedic criteria to analyze the amplitude of the curvature at the apex of the kyphosis, the curve pattern, the sagittal balance and sex bias, we demonstrate that pkd2l1 knock-outs develop a phenotype reminiscent of Scheuermann's disease. Altogether our work consolidates the benefit of combining genetics and analysis of spine deformities in zebrafish to model idiopathic spine disorders in humans.

Disease-Specific Outcome Measures Evaluating The Health-Related Quality Of Life Of Children And Adolescents With Idiopathic Scoliosis And Scheuermann's Kyphosis: A Literature Review

Adolescent idiopathic scoliosis (AIS) and Scheuermann's kyphosis (SK) are the most common types of spinal deformities in adolescents, and both have substantial ramifications on health-related quality of life (HRQoL) parameters. Various questionnaires have been developed to assess HRQoL in age-group populations with spinal deformity. Nevertheless, there remains a lack of consensus across the literature as to which instrument is the most suitable for evaluating the HRQoL of this cohort. Thus, this literature review was conducted to present disease-specific questionnaires for children and adolescents with AIS and SK to provide their psychometric characteristics (validity, reliability, and responsiveness) across different languages. A literature search was performed in the Medline (PubMed), Scopus, EMBASE, and Google Scholar databases. Studies that outlined the development and application of questionnaires evaluating HRQoL of children and adolescents with spinal deformity were included, and data on their validity and reliability in different translated languages were collected. A total of 10 disease-specific questionnaires were identified. Except for one questionnaire that was a proxy-reported measure, the other questionnaires were self-reported. We determined that selecting the proper questionnaire for clinical and research purposes requires careful consideration of various factors including the type of treatment intervention planned as well as various patient demographic factors. For children with early-onset scoliosis, the ideal questionnaire to evaluate their HRQoL is the Early-Onset Scoliosis Questionnaire-24. For adolescents with AIS and SK who are potential candidates for surgical intervention, the use of Scoliosis Research Society-22, Scoliosis Japanese-27, and Quality of Life Profile Spinal Deformity questionnaires is appropriate. For patients who are under nonsurgical treatment, the Brace Questionnaire and Italian Spine Youth Quality of Life questionnaires can be utilized. Nonetheless, when the specific intent of a study is to evaluate the self-image perception of patients, the use of drawing-based questionnaires may be the optimal choice.