Is the numerical rating scale an adequate predictor for assessing MRI underlying pathologies among painful adolescent idiopathic scoliosis patients?

The use of constant pain and night pain as clinical markers for predicting the presence of underlying pathology in painful adolescent idiopathic scoliosis (AIS) patients has been questioned. Pain intensity has been recognized as an important domain in pain assessment. The numerical rating scale (NRS) is one of the most commonly validated tools to assess pain intensity in children above 8 years of age. The aim of this study was to assess the NRS as a predictor of underlying pathologies found by MRI in painful AIS patients. A cross-sectional study comprising of all AIS patients with back pain lasting >4 weeks from April 2015 to April 2019 was performed. An MRI was performed on each AIS patient presenting with back pain after a nondiagnostic history, physical examination and spinal X-ray. The pain was graded using the NRS, ranging from 0 to 10. Patients were divided into three groups: NRS (1-3), NRS (4-6) and NRS (7-10). Variables, including gender, age, scoliosis magnitude and presence of underlying pathology, were compared between the groups. A total of 186 AIS patients were evaluated in the study, were 66/186 (35.5%) of them had underlying pathologies. The mean age of subjects was 14.7 years, 85% being female. An underlying pathology was identified in 4/11 (36.4%) with NRS (1-3), 28/82 (34.2%) with NRS (4-6) and 34/93 (36.6%) with NRS (7-10) (P = 0.94). The use of an NRS was not found to be an adequate predictor for identifying an underlying pathology via MRI in painful AIS patients.