Neck pain in military helicopter pilots: prevalence and associated factors.

Our aim is to estimate the self-reported one-year prevalence of neck pain in military helicopter pilots and to compare work-related, individual, and health-related factors in the pilots with (neck pain group) and without (reference group) regular or continuous neck pain. A questionnaire was completed by 75% (n = 113) of all military helicopter pilots of the Royal Netherlands Air Force and Navy. The reported one-year prevalence of any neck pain was 43%, and 20% for regular or continuous neck pain. Besides some significant differences in individual and health-related factors (also often reported in the general population), flying hours were significantly higher in pilots with neck pain compared to their colleagues without neck pain. The findings in this study suggest that neck pain in military helicopter pilots is a significant occupational problem and may be a consequence of longer exposure to flying.

Neck strength, position sense, and motion in military helicopter crew with and without neck pain.

INTRODUCTION: Neck pain in military helicopter pilots and rear aircrew is an occupational health problem that may interfere with flying performance. The aim of the present study was to investigate possible differences in the physical abilities of the cervical spines of helicopter pilots and rear aircrew with and without neck pain during the previous year. METHODS: The study included 61 male helicopter pilots and 22 rear aircrew without neck pain (Sx-) and 17 pilots and 17 rear aircrew with neck pain (Sx+). Active cervical range of motion (flexion-extension, right-left rotation, and right-left lateral flexion), neck position sense (reposition error back to neutral and defined positions after submaximal cervical movement), and maximum isometric neck muscle strength (flexion, extension, and right and left lateral flexion) were measured. Two-way factorial analyses of variance were performed, in which the fixed factors were occupation (pilot or rear aircrew) and neck pain state (Sx+ or Sx-). RESULTS: On average, there was a trend toward lower values in strength [extension: 55 (19) Nm vs. 58 (20) Nm; flexion 22 (8) Nm vs. 24 (12) Nm] and smaller cervical range of motion [flexion-extension: 132 degrees (19 degrees) vs. 137 degrees (15 degrees); rotation: 156 degrees (14 degrees) vs. 160 degrees (14 degrees)] in the total Sx+ crew, compared to their Sx- colleagues. However, the two-way factorial ANOVA revealed neither significant main effects nor significant interaction effects in any of the measured physical abilities. CONCLUSION: The results suggest that having experienced neck pain was not significantly associated with differences in the physical abilities of the cervical spines of helicopter crew, as assessed in this study.

MRI study of the morphometry of the cervical musculature in F-16 pilots.

INTRODUCTION: In fighter pilots neck muscle strengthening exercises are often recommended to protect the neck against pathologies. The aim of the current study was to compare the relative cross-sectional area (rCSA) and muscle:fat ratio of the cervical musculature of F-16 pilots experiencing neck pain and no neck pain (control) pilots. In addition, correlations between these morphometric characteristics, cervical range of motion (CROM), and neck muscle strength were evaluated. METHODS: There were 35 male F-16 pilots who volunteered, of which 10 experienced bilateral neck pain. A standardized questionnaire was used to collect personal information. Magnetic resonance imaging (MRI) was assessed at the C5-C6 level to determine rCSA and muscle:fat ratio. The CROM (Zebris) and the maximum isometric strength (David F140 device) were measured. RESULTS: The rCSA of the semispinalis cervicis and multifidus was significantly larger in the neck pain group (left: 2.08 cm2; right: 1.81 cm2) on both the left and the right side, in comparison to the control population (left: 1.29 cm2; right: 1.26 cm2). In the pain group, the rCSA of the semispinalis cervicis and multifidus was significant larger on the left than on the right side (left: 2.08 cm2; right: 1.81 cm2). No differences in the muscle:fat ratio between control pilots and pilots with neck pain could be determined. Between groups no differences were found in the CROM and the neck muscle strength. DISCUSSION: It is hypothesized that the larger rCSA in the neck pain group compared to the control group might be caused by greater activity of the deep neck muscles in the neck pain group. The asymmetrical operation of the F-16 might cause the asymmetry within this group.

Functional assessment of the cervical spine in F-16 pilots with and without neck pain.

INTRODUCTION: Spinal symptoms in fighter pilots are a serious aeromedical problem. The most common neck complaints are muscular pain and strain. The aim of the current study was to determine possible differences in the cervical range of motion (CROM), neck position sense, and neck muscle strength between pilots with and without neck pain. METHODS: There were 90 male F-16 pilots who volunteered, of which 17 had experienced bilateral neck pain. A standardized questionnaire was used to collect personal information. The maximum isometric neck flexion/extension and lateral flexion strength, the neck position sense, and the cervical range of motion were measured. RESULTS: There were no significant differences between healthy pilots and those with neck pain concerning neck muscle strength and neck position sense. The neck pain group had a limited CROM in the sagittal plane (130 degrees; CI: 116 degrees-144 degrees) and in the transversal plane (155 degrees; CI: 140 degrees-170 degrees) compared to the healthy pilots. DISCUSSION: In the current study we screened for different motor skills so that deficits could be detected and retraining programs could be implemented when necessary. According to our results, individual retraining programs might reduce neck pain and therefore a well-instructed training program to maintain a proper active CROM should be implemented. Future studies should investigate the effectiveness of this kind of program.

Individual, work-, and flight-related issues in F-16 pilots reporting neck pain.

INTRODUCTION: Neck pain is a common problem in F-16 pilots. A cross-sectional survey was used to determine the self-reported 1-yr prevalence of neck pain and to compare individual, work-related, and flight-related characteristics in F-16 pilots with and without neck pain. METHOD: There were 90 male F-16 pilots of the Belgian Air Force and The Royal Netherlands Air Force who voluntarily completed an anonymous survey. RESULTS: The 1-yr prevalence of neck pain was 18.9%. Pilots were divided into two groups: healthy (HG) and neck pain group (NPG). This study could not identify individual or specific flight-related differences between these two groups. High force demands, often sitting for a long time, frequently holding the neck in a forward bent posture, and being physically tired were all physical work-related factors that were reported significantly more often in the NPG. The NPG also reported significantly more psychosocial factors, such as being mentally tired at the end of the day and being annoyed by others at the workplace. DISCUSSION: Since the specific flight-related factors were not significantly different between the HG and the NPG, physical and psychosocial factors could have been important factors in the development or maintenance of neck pain in F-16 pilots. CONCLUSION: The results of this study highlight for the first time that, in addition to flight-related issues, other aspects must be considered in analyzing neck pain. These other aspects stress the importance of a broader approach when considering neck pain, even in this population that is exposed to very high loads during flight.

Prevalence and risk factors of neck pain in military office workers.

An extensive cross-sectional questionnaire was used to estimate the prevalence of neck pain and to identify risk factors (short term to long term) in the occurrence of neck pain in military office workers. Two standardized scales (Neck Disability Index and Tampa Scale for Kinesiophobia) allowed assessment of the impact of neck pain on the person's life and the pain-related fear avoidance. A total of 629 completed questionnaires were evaluated which revealed the following: lifetime prevalence (78%), week prevalence (53%), point prevalence (59%), year prevalence (65%) (once-only, 19%; regular, 51%; long term, 15%; never, 7%). The results of this study provided support for the role of physical and psychosocial job characteristics in the etiology of neck pain in military office workers.

Differences in isometric neck muscle strength between healthy controls and women with chronic neck pain: the use of a reliable measurement.

OBJECTIVES: To determine the intra- and interrater reliability of the Biodex isokinetic dynamometer to measure the maximal isometric strength of the cervical flexors and extensors, to develop an age- and sex-based normative database in a healthy population, and to evaluate the differences in neck strength between women with chronic neck pain and healthy controls. DESIGN: Cross-sectional. SETTING: Physical and rehabilitation medicine department. PARTICIPANTS: Ninety-six healthy volunteers (4 age groups: 20-29, 30-39, 40-49, 50-59y; each consisting of 12 men and 12 women) and 30 women with chronic neck pain. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Peak isometric strength of the cervical muscles was tested for flexion and extension by using the Biodex isokinetic dynamometer. The intra- and interrater reliability of the protocol was evaluated in 12 volunteers. RESULTS: The reliability for strength was high for both flexion and extension (intraclass correlation coefficient, .92-.96). The mean peak torque for flexion and extension was significantly higher in men (24Nm, 36.4Nm, respectively) compared with women (16.6Nm, 26.5Nm, respectively) (P<.001). Peak torque production for extension was significantly lower in the patient group (22.3Nm) compared with the healthy female control group (26.5Nm) (P=.003). No significant differences in flexion strength between patient and female control group were found. CONCLUSIONS: Results show a high degree of intra- and interrater reliability in measuring isometric neck muscle strength when using the Biodex isokinetic dynamometer. The use of normative data for neck strength when evaluating patients with neck disorders needs to take sex into account. The current study has shown that women with chronic neck pain have lower neck muscle strength in extension than the healthy female group.

Reliability and normative database of the Zebris cervical range-of-motion system in healthy controls with preliminary validation in a group of patients with neck pain.

OBJECTIVE: The first aim of this study was to determine the reliability of the Zebris (Achen, Germany) ultrasound-based testing of cervical range of motion (ROM). The second aim was to develop a normative database in a healthy sample of 96 volunteers. The third aim was to evaluate, with the Zebris system, the ROM in a sample of patients with chronic neck pain compared to healthy controls to determine if cervical ROM could discriminate between these groups and between subgroups of pain patients (with or without whiplash injury). METHODS: The study participants were 96 healthy volunteers, 14 patients with idiopathic neck pain, and 16 patients with chronic whiplash. Cervical ROM was measured in the 3 planes with the Zebris CMS 70P ultrasound-based motion analysis system. The intra- and interrater reliability of the protocol was tested in 12 volunteers. RESULTS: Full-cycle measurements showed high reliability (intraclass correlation coefficient, 0.80-0.94) with the SE of measurement ranging from 4.25 degrees to 7.88 degrees. The distribution of ROM measures showed a great individual variation, with a significant age-related decrease in ROM in all directions. Range of motion was reduced in patients with chronic whiplash in all primary movements, compared to healthy subjects, whereas in patients with idiopathic neck pain, only rotation showed reduced ROM. CONCLUSION: Results demonstrate a high degree of test-retest reliability in measuring cervical ROM. The use of normative data for ROM when evaluating patients with neck disorders needs to take age into account. The current study has demonstrated that patients with chronic neck pain demonstrate reduced ROM, which differs between patients with idiopathic neck pain and those with chronic whiplash.