Due to the lack of high-level research evidence for the long-term clinical efficacy of spinal MUA, several traditional criteria for patient selection are without support or remain unproven. The most recent analysis of the published medical evidence for MUA shows that disc herniation/protrusion qualifies as at least a relative contraindication, with risk for injury and no proven long-term benefit. Also, in the presence of a positive lumbar EMG study (nerve root compression) with lumbar disc herniation, Level II evidence suggests that patients will eventually need surgical correction. For chronic neck and low back pain patients who also have significant anxiety/stress, Level II evidence suggests that MUA will not be of therapeutic benefit. Accordingly, most insurance carriers in the United States maintain medical policy which deems the spinal MUA unproven or experimental/investigational.