The effectiveness of manual therapy in cervical range of motion, head repositioning accuracy and postural stability in patients with chronic mechanical neck pain : a randomized controlled trial

Abstract

The first part of this thesis focused on examining the inter-relationship among cervical range of motion (ROM), head-repositioning accuracy (HRA) and standing postural stability (measured by the Biodex Balance System - BBS) in normal healthy individuals. A correlational study with convenient sampling was conducted with 30 normal subjects (without previous history of neck pain for recent 6 months). Cervical ROM was shown to be negatively correlated to HRA and postural stability (p<0.05) although the correlation coefficient was poor (r ranged from -0.0017 to 0.064). HRA was positively correlated to postural stability (p<0.05), with reliability coefficient ranged from 0.12 to 0.41. Results also demonstrated positive correlation between age and all variables (p<0.05), while gender did not show any effect on the outcomes. The second part of the thesis investigated the difference and relationships among the above outcomes in patients with chronic mechanical neck pain. In addition, the relationship among patients' subjective pain intensity (measured in Numeric Pain Rating Scale - NPRS) (with cervical ROM, HRA and postural stability) were also compared and analyzed. Thirty normal individuals without recent neck pain for 6 months and 30 patients with chronic mechanical neck pain were recruited in the Physiotherapy Department, Prince of Wales Hospital with inclusion and exclusion criteria met. The results showed negative correlation between HRA and postural stability, while HRA was positively correlated to postural stability (ROM vs. HRA: r ranged from -0.31 to 0.48; ROM vs. BBS: ranged from -0.22 to -0.49; HRA vs. BBS: r ranged from 0.12 to 0.59; p<0.05) in 30 neck pain patients. All outcome measures from neck pain patients were poorer when compared with those in normal individuals (p<0.05). Nevertheless, these outcomes were not related to NPRS. The major part of the thesis involved in a randomized controlled clinical trial undertaken to investigate the effects of cervical manual therapy (mobilization and manipulation) on patients with chronic mechanical neck pain. One hundred and forty-seven patients were recruited from the Physiotherapy Department, Prince of Wales Hospital and randomized into a manual therapy (MT) group and a control (CON) group. The age range of the MT group was from 19 to 66 (mean age 46.6±10.0) and that of the CON group was from 23 to 63 (mean age 45.5±9.5). The patients in the MT group received manual therapy, 15-minutes of irradiation therapy (IRR) together with neck exercises listed in a neck exercise pamphlet, whereas those in the CON group only received IRR and neck exercises. All patients received 8 sessions of treatment over a 4-week interval. The outcome measures included subjective pain intensity (NPRS), neck disability (NPQ), cervical ROM, HRA and postural stability (BBS). Assessments were made by a blinded assessor at baseline, immediately post-intervention (completion of 8 sessions of treatment), 3 months and 6 months after completion of treatment. No statistically significant differences were found between the two groups in any of the outcome measures in the baseline comparison. After 8 sessions of intervention over a 4-week period, patients in the MT group had realized greater improvement than those in the CON group in cervical ROM (12.85% vs. 1.11%), HRA (25% vs. 3.32%), postural stability (BBS) (38.3% vs. 17.19%) and NPRS (38.9% vs. 10.2%) (p<0.05) except for NPQ (38.9% vs. 10.2%). Throughout the study period at 6 months post-intervention, there were significant improvement (p<0.05) in the MT group in all outcome measures except for HRA in flexion and NPQ. Most of the outcome measures in the MT group were better than those in the CON group, and the improvements were sustained over 6 months post-intervention (mean improvement in cervical ROM 13.7%; HRA 30.56%; BBS 38.3%). It is concluded that 4 weeks of manual therapy in terms of spinal mobilization or manipulation together with neck exercises is effective in improving cervical ROM, head-repositioning accuracy, static postural stability, and subjective pain intensity in patients with non-traumatic chronic mechanical neck pain up to 6 months post-treatment.