Wirbelsäulenform- und Funktionsprofile

[Reference values for isometric strength tests]

BACKGROUND

In the environment of orthopaedic rehabilitation, isometric strength testing is part of the monitoring in order to document the success of the therapy. For clinical applications, reference values, or at least orientation benchmarks, are needed for every single device, because of serious concerns for direct inter-device comparisons. According to functional ratios, there is only little literature covering comparability concerns. This study aimed to demonstrate reference values for two strength diagnosis systems for trunk and knee-joint flexion and extension as well as resulting functional ratios along with analyses of reproducibility and vice-versa comparisons.

MATERIALS AND METHODS

In a cross-sectional design, reference values (M, SD, Median, IQR, 5 and 95% percentiles) of 98 healthy adults (47 females, age 25.7±8.2 years, BMI 23.3±2.6 kg/m2) were assessed for trunk and knee flexion and extension and the according functional ratios using either the Myoline or the Frei medical system. For a sub-sample of 20 persons (50% females), the mutual explained total variance (r2) and reliability (ICC3.1, SEM, VK%) were analyzed.

RESULTS

Both systems were shown to be reliable (ICC3.1 0.76-0.95), while functional ratios demonstrated a lower reliability (ICC3.1 0.62-0.92). For peak forces, the mutual total explained variance (r2) ranged between 19-68%, for functional ratios on an even lower level (5-21%).

CONCLUSION

The resulting strength test values, and especially the related functional ratios, obtained with the two strength test devices are not comparable at all, but each device was shown to be a reliable tool. Distributions of body weight adjusted peak forces and functional ratios may serve as device specific benchmark values for strength testing in clinical environments.

Reference Values for 3D Spinal Posture Based on Videorasterstereographic Analyses of Healthy Adults

Visual examinations are commonly used to analyze spinal posture. Even though they are simple and fast, their interrater reliability is poor. Suitable alternatives should be objective, non-invasive, valid and reliable. Videorasterstereography (VRS) is a corresponding method that is increasingly becoming established. However, there is a lack of reference data based on adequate numbers of participants and structured subgroup analyses according to sex and age. We used VRS to capture the spinal posture of 201 healthy participants (aged 18-70 years) divided into three age cohorts. Three-dimensional reference data are presented for the global spine parameters and for every vertebral body individually (C7-L4) (here called the specific spine parameters). The vertebral column was found to be systematically asymmetric in the transverse and the coronal planes. Graphical presentations of the vertebral body posture revealed systematic differences between the subgroups; however, large standard deviations meant that these differences were not significant. In contrast, several global parameters (e.g., thoracic kyphosis and lumbar lordosis) indicated differences between the analyzed subgroups. The findings confirm the importance of presenting reference data not only according to sex but also according to age in order to map physiological posture changes over the life span. The question also arises as to whether therapeutic approximations to an almost symmetrical spine are biomechanically desirable.

[Reference values in isometric strength diagnostics : Measurement of core strength values in patients with back pain]

OBJECTIVE

Isometric strength testing is known as a valid and reliable tool in the context of functional diagnostics and quality control for chronic low back pain rehabilitation, but reference values differ markedly between varied assessment devices, depending on their biomechanical lever arm framework. This study aimed to evaluate sex and age-specific isometric peak force reference values of trunk muscle functions in all dimensions using the Myoline® test device (Diers, Schlangenbad, Germany).

MATERIAL AND METHODS

In a retrospective cross-sectional study, data of 678 (541 females, 137 males) age-clustered (18-35, 36-50, 51-65 years) low back pain patients (ICD-10: M54) were analyzed referring to their absolute (N) and body weight related (N/kg) isometric maximum peak forces in all spatial dimensions (flexion, extension, rotation, lateral flexion) and the corresponding ratios (M ± SD, 95% CI), accompanied by sex and age-related effect analyses (two-way ANOVA).

RESULTS

Male and younger patients were significantly stronger than females and older patients (p < 0.05), but none of the ratios differed significantly between any sex or age cluster (p > 0.05). The flexion/extension ratio showed a 1:2 relation, and the rotation and lateral flexion ratios demonstrated a 1:1 relation, but all ratios varied markedly (30-50%).

CONCLUSIONS

The demonstrated data represented a special norm for sex and age clustered low back pain patients assessed with the recent Myoline® test device. The markedly varying peak forces and their ratios underlined the individual diversity and heterogeneous state of functional capacities within low back pain patients.

Age-related loss of lumbar spinal lordosis and mobility--a study of 323 asymptomatic volunteers

Background

The understanding of the individual shape and mobility of the lumbar spine are key factors for the prevention and treatment of low back pain. The influence of age and sex on the total lumbar lordosis and the range of motion as well as on different lumbar sub-regions (lower, middle and upper lordosis) in asymptomatic subjects still merits discussion, since it is essential for patient-specific treatment and evidence-based distinction between painful degenerative pathologies and asymptomatic aging.

Methods and Findings

A novel non-invasive measuring system was used to assess the total and local lumbar shape and its mobility of 323 asymptomatic volunteers (age: 20–75 yrs; BMI <26.0 kg/m²; males/females: 139/184). The lumbar lordosis for standing and the range of motion for maximal upper body flexion (RoF) and extension (RoE) were determined. The total lordosis was significantly reduced by approximately 20%, the RoF by 12% and the RoE by 31% in the oldest (>50 yrs) compared to the youngest age cohort (20–29 yrs). Locally, these decreases mostly occurred in the middle part of the lordosis and less towards the lumbo-sacral and thoraco-lumbar transitions. The sex only affected the RoE.

Conclusions

During aging, the lower lumbar spine retains its lordosis and mobility, whereas the middle part flattens and becomes less mobile. These findings lay the ground for a better understanding of the incidence of level- and age-dependent spinal disorders, and may have important implications for the clinical long-term success of different surgical interventions.