... Operation Emergency Retreat Key.Indications:Protrusion of lumbar intervertebral disc, Thorocic vertebra small joint ... dislocation, Compression fracture of thorocic and lumbar vertebra, Traumatic cervical fracture,Malposition and dislocation, ... languarge barriers and so on.Contraindication:Huge lumbar disc herniation, Lumbar Spine tuberculosis, Tumour, Severe osteoporosis, Hypertension, ...