Table 2.

NSD drivers

	Categories	Operational definition
A	Peripheral or central NSDs	Neuropathic pain is a type of pain caused by a lesion or disease of the somatosensory nervous system. Hence, the peripheral nervous system can be a cause of pain associated with LBP. Clinical manifestations of neuropathic pain associated with LBP have specific characteristics: paresthesia, tingling, burning, or shooting pain. Studies have shown that these pain characteristics and radicular pattern of pain (including radiculopathy) provide evidence of peripheral NSD.36
B	Nervous system hypersensitivity	This category also involves NSD and concerns elements related to peripheral, spinal, or supra-spinal hypersensitivity. This category conveys to more “serious” clinical manifestations such as evidence of mechanosensitivity, hyperalgesia, allodynia, evidence of widespread pain location, or disproportional pain intensity, which have been shown to be important indicators of spinal and supra-spinal hypersensitivity in LBP patients.36,37 In this context, nervous system hypersensitivity would be contributing factors driving the painful symptoms.

Abbreviations: LBP, low back pain; NSD, nervous system dysfunction.