eTable 1. Types of low back pain associated with physical findings of no clear pathoanatomical significance.

Syndrome	Findings	Assessment/Plan
Facet syndrome	History and physical examination: local and pseudoradicular symptoms and signs pain on movement facet tenderness pain on reclination positive injection test joint dysfunction on manual diagnosis Radiological findings (not indicated on intial evaluation): differentiation from high-grade or activated spondylarthrosis (possibly, juxtaforaminal cyst) or axial spondylarthritis	Differential diagnosis: major joint dysfunction (blockage) activated spondylarthrosis Treatment: analgesics (1–3 days), muscle stabilization, manual medicine, facet injection if indicated
Sacro-iliac joint syndrome	History and physical examination: sactro-iliac joint symptoms, positive provocation test functional leg length discrepancy injection test Radiological findings (not indicated on intial evaluation): differential diagnosis: inflammation (sacro-iliitis in seronegative spondylarthritis)	Functional disturbance: muscular imbalance Treatment: stabilizing exercises, analgesics (1–3 days) if needed, manual medicine, sacro-iliac joint injection if indicated
Myofascial pain syndrome	History and physical examination: muscle trigger points: local pain with peripheral radiation peripheral and central sensitization Radiological and histological findings: not indicated no clear evidence from MRI or biopsy	pathogenesis and definitive diagnosis still unclear (low intra- and interrater reliability) Local treatment: active physiotherapy, manual therapy, infiltration, acupuncture
Functional instability	History and physical examination: “snapping” feeling generalized deconditioning pain on movement, possibly accompanied by ‧sensory and motor deficits (reversible) impaired proprioception Radiological findings: no direct evidence	unclear pathogenesis and definition treatment with manual medicine physiotherapeutic stabilization program caveat: surgery, differential diagnosis, structural instability

MRI, magnetic resonance imaging