Purpose: The nature and type of pain in the low back (LBP) is complex. The PainDETECT questionnaire is a screening tool to discriminate between neuropathic, nociceptive and ambiguous pain. The purpose of this study was to assess the relationship between PainDETECT scores and lumbar intervertebral degenerative and stenosis parameters in paired imaging.
Methods: A secondary review of 279 consecutively patients, above 18-years-of-age with completed PainDETECT questionnaires, lumbar MRI and/or X-ray scans was conducted. Of the 279 patients included in the study, 102 had nociceptive, 78 had ambiguous and 99 had neuropathic pain as described by the PainDETECT questionnaire.
Results: Nociceptive group had highest mean age, followed by ambiguous and neuropathic group (58.21 vs. 55.33 vs. 53.63, p=0.04). The neuropathic group had highest mean NRS, followed by ambiguous and nociceptive (7.9 vs. 6.9 vs. 5.9, p<0.001). There was a positive relationship between PainDETECT score and foraminal stenosis (=0.422, p<0.001), spinal stenosis (=0.332, p<0.001) and pfirmann grade (=0.324, p<0.001), and a negative relationship between PainDETECT score and pelvic incidence (=-0.177. p=0.45). The distribution of foraminal stenosis (H(2)=12.742, p=0.002), spinal stenosis (H(2)=9.948, p=0.007) and pfirmann grade (H(2)=6.823, p=0.033) was significantly different across the three PainDETECT groups. There was a significantly higher foraminal stenosis severity (U=18.962, p=0.002), spinal stenosis severity (U=14.481, p=0.005) and pfirmann grade (U=14.221, p=0.028) in the neuropathic group compared to the nociceptive group. There was significantly higher number of neuropathic patients with intervertebral disk bulge (96% vs. 78% vs. 78%, p=0.002) and high intensity zones (51% vs. 41% vs. 19%, p<0.001) compared to patients with nociceptive pain and ambiguous pain.
Conclusion: Neuropathic pain as classified by the PainDETECT questionnaire is associated with increased neural compression severity, increased discogenic disease and inflammatory disk severity, and decreased pelvic incidence. This is the first study to link pathological findings with pain categorisation and will allow clinicians to formulate clear management plans, and reduce the level of unnecessary pharmacotherapy, imaging and untargeted surgical interventions.