Pain related aspects of neck muscle performance, functioning and psychosocial factors in individuals with cervical radiculopathy

Abstract: Aim: The overall aim of the work presented in this thesis was to describe and explore pain-related aspects of neck muscle performance, functioning and psychosocial factors in individuals with cervical radiculopathy (CR). Methods: Participants were 157 patients with CR. Also Study II included 33 asymptomatic age-and gender-matched controls. Study I, a prospective randomized controlled pilot trial, investigated outcomes after anterior cervical discectomy and fusion (ACDF) with interbody cage with (n=17) or without (n=16) cervical collar in CR. In Study II and III, ventral and dorsal neck muscle fatigue was recorded with surface electromyography (EMG) during isometric endurance (NME) tests. Study II compared a CR group (n=46) with healthy controls (n=34). In Study III, results after neck-specific training or prescribed physical activity (n=50) were analyzed. Pain was estimated using visual analogue scales (VAS) and perceived fatigue rated with Borg CR-10 scales before, during and after the tests. Cross-sectional, Study IV, identified dimensions underlying measures of impairments, disability, personal factors, and health status in patients with CR (n=124). Results: Study I, Both groups improved in all outcome measures, with a significant improvement from baseline to two years after surgery. Cervical collar worn for six weeks postoperatively, were associated with enhanced neck function and less neck pain even at long-term. Study II showed altered neck muscle endurance investigated with greater negative median frequency slope, variability, side imbalance, lower endurance time, and higher experience of fatigue among in the CR group compared to the healthy controls. Patients with CR had significantly shorter endurance time. In Study III, significant improvement in flexor NME was found after training, but with no difference between training groups. For the neck-specific training group only, there less activation of the splenius capitis during neck flexion after 14 weeks and one year, indicating reduced co-activation of the neck muscles. In Study IV, the PCA model provided three-components: Pain and functioning, Health, beliefs, and kinesiophobia, and Mood state and catastrophizing. These accounted for 73% of the cumulative percentages. Conclusions: Cervical collar post-surgery can help deal with initial post-operative pain and reduce disability. Shorter endurance and higher experience of fatigue was perceived among patients with CR compared to healthy subjects. Exercises increased flexor NME regardless of exercise group. The neck-specific group indicated reduced compensation of antagonist muscles during flexion contraction. To capture a broad picture of patients with CR pain, their functioning, fear avoidance beliefs, and anxiety are important factors in a clinical perspective.