McKenzie mechanical syndromes coincide with biopsychosocial influences, including central sensitization: a descriptive study of individuals with chronic neck pain.

Background: Mechanical diagnosis and therapy (MDT) aims to assess and classify patients into theoretically mutually exclusive subgroups, in order to direct treatment. However, the latest evidence for biopsychosocial influence-central sensitization (CS) and psychological distress-have not been assessed in conjunction with MDT.

Objectives: (1) Determine the percentage of patients categorized into the MDT subgroups; (2) characterize the biopsychosocial clinical profile (presence of CS and psychological distress); and (3) identify associations between pain, disability, and biopsychosocial influences among this cohort.

Methods: Eighty four patients with chronic neck pain were recruited by 10 certified MDT therapists using a convenience (consecutive) sampling method. Patients were evaluated using MDT principles and also completed an online survey to measure CS (using the Central Sensitization Inventory [CSI]), pain catastrophizing and kinesiophobia.

Results: The proportions of the subgroups derangement (DER), dysfunction, postural and 'other' were 74.4, 2.4, 1.2, 20.7%, respectively. CS was observed in 62% of our sample (CSI score ≥ 40). CS was also observed in 64.7% of patients of the DER subgroup. Almost half of our sample (47.8%) demonstrated the co-occurrence of CS and DER, while 38% presented with DER syndrome, CS, and kinesiophobia.

Conclusion: The majority of our patients were classified as DER; they also presented with high levels of CS and/or psychological distress. This suggests that MDT mechanical subgroups, particularly DER, can present with co-occurring biopsychosocial influences. Without assessing CS and psychological distress, MDT therapists may miss crucial information. Further research is required to determine the optimal management of patients presenting with mechanical and non-mechanical drivers of pain.