Effect of Additional Pain Neuroscience Education in Interdisciplinary Multimodal Pain Therapy on Current Pain. A Non-Randomized, Controlled Intervention Study.

PURPOSE: Interdisciplinary multimodal pain therapy (IMPT) programs for chronic back pain are effective and recommended. The patient-centered and biopsychosocial nature of IMPT is grounded in contemporary understanding that chronic pain states reflect heightened sensitization of the nervous system rather than an issue in the tissue. Teaching patients about pain is part of IMPT programs, though a clinical guideline is lacking. This study aims to answer the following question: Does the addition of an evidence-based pain neuroscience education (PNE) lecture for patients, into an IMPT program, produce superior results than the IMPT program itself? PATIENTS AND METHODS: A non-randomized, controlled intervention study was performed with 179 back pain patients indicated for IMPT. Intervention group (N=102) received a four-week IMPT program, which contained 4 one-hour sessions PNE. Control group (N=77) received the same IMPT without the additional PNE. Primary outcome was current pain after intervention. Pain knowledge, physical function, depression, anxiety, stress, quality of life and fear-avoidance were analyzed as secondary outcomes. Outcomes were defined as change of the parameter measured before and immediately after the four-week IMPT. For each outcome, linear regression models were used to estimate the raw and adjusted (sex, age and BMI) effect of additional PNE. RESULTS: Despite improvement in all outcomes for both groups during the treatment phase, the implemented PNE did not result in additional pain reduction (regression coefficient for PNE effect on pain level 0.34; 95% CI -6.23-6.97). Between-group differences could only be shown for pain-related knowledge in favor for the intervention group (0.78; 95% CI 0.35-1.20). CONCLUSION: The additional PNE lecture did not lead to pain reduction beyond the usual IMPT. However, the PNE did increase pain-related knowledge and, therefore, might be helpful in coping with pain after the IMPT program.

Low back related leg pain: an investigation of construct validity of a new classification system.

BACKGROUND: Leg pain is associated with back pain in 25-65% of all cases and classified as somatic referred pain or radicular pain. However, distinction between the two may be difficult as different pathomechanisms may cause similar patterns of pain. Therefore a pathomechanism based classification system was proposed, with four distinct hierarchical and mutually exclusive categories: Neuropathic Sensitization (NS) comprising major features of neuropathic pain with sensory sensitization; Denervation (D) arising from significant axonal compromise; Peripheral Nerve Sensitization (PNS) with marked nerve trunk mechanosensitivity; and Musculoskeletal (M) with pain referred from musculoskeletal structures. OBJECTIVE: To investigate construct validity of the classification system. METHODS: Construct validity was investigated by determining the relationship of nerve functioning with subgroups of patients and asymptomatic controls. Thus somatosensory profiles of subgroups of patients with low back related leg pain (LBRLP) and healthy controls were determined by a comprehensive quantitative sensory test (QST) protocol. It was hypothesized that subgroups of patients and healthy controls would show differences in QST profiles relating to underlying pathomechanisms. RESULTS: 77 subjects with LBRLP were recruited and classified in one of the four groups. Additionally, 18 age and gender matched asymptomatic controls were measured. QST revealed signs of pain hypersensitivity in group NS and sensory deficits in group D whereas Groups PNS and M showed no significant differences when compared to the asymptomatic group. CONCLUSIONS: These findings support construct validity for two of the categories of the new classification system, however further research is warranted to achieve construct validation of the classification system as a whole.

Interrater reliability of a new classification system for patients with neural low back-related leg pain.

The aim of this study was to investigate the reliability of a new classification system for low back-related leg pain arising from neural tissue dysfunction. Leg pain is a frequent accompaniment to back pain and is an indicator of the severity and prognosis of the disorder. For optimal patient care, treatment should be directed according to the identified pathophysiological mechanisms. The authors have proposed a sub-classification of neural low back-related leg pain into four categories, each requiring a different management strategy: Central Sensitization (CS), comprising major features of sensitization of the somatosensory system; Denervation (D), arising from significant axonal compromise without evidence of major central nervous system changes; Peripheral Nerve Sensitization (PNS), arising from nerve trunk inflammation without clinical evidence of significant denervation; and Musculoskeletal pain (M), referred from non-neural structures such as the disc or facet joints. The purpose of this study was to investigate the interrater reliability of this classification system. Forty consecutive patients with unilateral low back-related leg pain were independently assessed by five pairs of examiners using a physical examination protocol, screening for central sensitization of the somatosensory system, neurological deficit, and nerve tissue mechano-sensitization. Subjects were classified as follows: CS 30%, D 27.5%, PNS 10%, and M 32.5%. Interrater reliability was good with 80% agreement and a k of 0.72 (95% Confidence Interval (CI) .57-.86). The findings of the study demonstrate that patients with low back-related leg pain can be reliably classified to one of the four proposed groups.