DP/CEN and DP/non-CEN are common pain pattern responses assessed by Mechanical Diagnosis & Therapy (MDT). Although there is evidence that MDT can reduce pain and disability in the short term by treating the patient with direction-specific exercises concordant with the patient’s DP, the mechanism responsible for this is unclear. The objective of this study was to determine if clinical signs of impaired spinal control improve immediately after eliciting a directional preference with centralization response (DP/CEN), or a directional preference without centralization response (DP/non-CEN), in patients with nonspecific low back pain (LBP). Participants underwent a standardized MDT assessment and were classified in a pain pattern subgroup; DP/CEN, DP/non-CEN, or no-DP. Clinical signs of impaired spinal control were assessed pre- and post-MDT assessment by an independent examiner. Four spinal control tests were conducted: aberrant lumbar movements while bending forward, the active straight leg raise (ASLR) test, the Trendelenburg test and the prone instability test. Differences in spinal control pre- and post-MDT assessment were calculated for the three pain pattern subgroups and compared with Chi-square tests. The authors hypothesized that a larger proportion of patients in the DP/CEN subgroup would improve on spinal control than patients categorized as DP/non-CEN or no-DP. Of 114 patients recruited, 51 patients (44.7%) were categorized as DP/CEN, 23 (20.2%) as DP/non-CEN, and 40 (35.1%) as no-DP. Before MDT assessment between 28.9% (Trendelenburg test) and 63.7% (ASLR test) of patients showed impaired spinal control. After MDT assessment a larger proportion of patients in the DP/CEN subgroup (43%) showed improvement than those in the no-DP subgroup (7%) on aberrant lumbar movements (P = .02). Likewise, more patients in the DP/CEN subgroup (50%) improved on the ASLR test than in the no-DP subgroup (8%, P < .01) or the DP/non-CEN subgroup (7%, P = .01). Changes in Trendelenberg and prone instability tests did not reach statistical significance.
Immediately following MDT assessment, a larger proportion of patients with a DP/CEN pain pattern showed improvement in clinical signs of spinal control compared to patients with a DP/non-CEN or no-DP pain pattern.