The peculiarities and treatment outcomes of the spinal form of chronic non-bacterial osteomyelitis in children: a retrospective cohort study

Chronic non-bacterial osteomyelitis (CNO) is a group of immune-mediated diseases which appears in bone inflammation, destruction and some orthopaedic consequences, especially in the cases of spinal involvement. This study is to compare characteristics and treatment outcomes of CNO patients with spinal involvement. The retrospective cohort study included data from 91 pediatric patients with CNO. The diagnosis is based on Jannson's criteria with morphological confirmation (nonspecific chronic inflammation). Spine involvement detected by X-ray, computed tomography, magnetic resonance imaging, and bone scan in 29 (31.9%) patients. No differences in the family history, concomitant immune-mediated diseases between spinal (SpCNO) and peripheral (pCNO) forms of CNO have been revealed. Only 5 (10.2%) SpCNO patients (10.2%) had monofocal monovertebral involvement. The main risk factors of spinal involvement were female sex: RR = 2.0 (1.1; 3.9), sensitivity (Se) = 0.66, specificity (Sp) = 0.6; multifocal involvement: RR = 2.1 (0.9; 5.0), Se = 0.83, Sp = 0.37; no foot bones involvement: RR = 3.1 (1.3; 7.5), Se = 0.83, Sp = 0.5; sternum involvement RR = 2.3 (1.3; 4.1), Se = 0.24, Sp = 0.94. In the linear regression analysis only female sex (p = 0.005), multifocal involvement (p = 0.000001) and absence of foot bones involvement (p = 0.000001) were independent risk factors of spinal involvement (p = 0.000001). The response rate on bisphosphonates and tumor necrosis factor-a inhibitors was 90.9% and 66.7%, consequently. Only 4/29 (13.8%) SpCNO patients underwent surgery due to severe spinal instability or deformities. The spinal involvement is frequent in CNO and could be crucial for choosing a treatment strategy. Bisphosphonates and TNFa-inhibitors could be effective treatment options for severe SpCNO.