Table 4 Definitions and Evidence-Based Criteria for Conditions Arising From Neuropathic Processes

Neuropathic pain
Pain caused by a lesion or disease of the somatosensory nervous system
•History of lesion or disease of nervous system•Comorbidities relating to neuropathic pain•Pain neuroanatomically distributed•Sensory dysfunction neuroanatomically distributed•Burning, shooting, or pricking pain description Expert consensus-based IASP criteria 14 , 59
Radicular pain
Pain from ectopic activation of nociceptors in a spinal nerve or its roots or from other mechanisms (eg, inflammation, tensile strain)
•Lancinating•Travels along narrow region•Pain beyond the spine•May be episodic, recurrent, or paroxysmal Expert consensus criteria 60
Objective sensory and/or motor function loss caused by conduction block in axons of a spinal nerve or its roots
•Objective findings of nerve root conduction loss in the distribution of a spinal nerve (eg, reduced deep tendon reflex, reduced motor strength, and/or reduced sensation corresponding to a nerve root) Expert consensus criteria 60
Neurogenic claudication
Pain from intermittent compression and/or ischemia of a single or multiple nerve roots within an intervertebral foramen or the central spinal canal
•Symptoms triggered with standing•Symptoms relieved when sitting•Symptoms primarily located above knees•Positive shopping cart sign Diagnostic study using expert diagnosis, imaging, and vascular testing 49
Piriformis syndrome
Pain from inflammation, compression, or entrapment of the sciatic nerve in the region of the piriformis muscle
•Radiating pain into an ipsilateral leg•Tenderness of the greater sciatic notch•Buttock pain•Positive SLR test•Increased pain with prolonged sitting Most common characteristics described in the clinical literature 23
Thoracolumbar (Maigne’s) syndrome
Cluneal nerve entrapment causing low back and/or lower extremity pain
•Pain in cluneal nerve distribution (iliac crest, groin, or greater trochanter)•Trigger point over iliac crest approximately 7 cm from midline•Sensitivity to iliac crest skin rolling•Tenderness of 1 or more thoracolumbar spinous processes or facet joints Expert description of condition 65 , 82
Central sensitization
Increased responsiveness of nociceptive neurons to their normal input, and/or recruitment of a response to normally subthreshold inputs
•Low back pain disproportionate to nature or extent of injury/pathology (ie, there is insufficient evidence for tissue injury, pathology, or other dysfunction to explain self-reported symptoms)•Neuroanatomically illogical pattern (eg, pain varying in location, abnormally large painful area, completely symmetrical pain pattern)•Hypersensitivity of senses unrelated to musculoskeletal system (eg, heat, cold, or pressure hypersensitivity; generalized sensitivity remote from low back area; hypersensitivity to light, sound, stress, food, chemical stimuli) Expert consensus criteria 59

IASP = International Association for the Study of Pain;
SLR = straight leg raise.