Background Although traction has long been used for treating patients with low back pain (LBP), its effects are still inconclusive mainly because of limited high-quality evidence. Objective To provide evidence of the mechanism of traction on lumbar intervertebral discs. Design A quantitative approach with a repeated measurement protocol. Method Nine participants (mean age = 22.1 ± 0.8 years) without any LBP history were recruited. Magnetic Resonance Images of the lumbar spine of each participant were recorded before and after 30 min of horizontal lying and directly after 30 min of horizontal traction of 42% body weight. The average, anterior, central, and posterior disc height and tilt angle of each lumbar disc and lumbar lordosis were measured. Results A significant increase in the average disc height for all lumbar discs, a significant reduction of lumbar lordosis and changes in tilt angle were observed after the application of 30 min of resting followed by 30 min of traction. A significant increase in the average disc height was observed only in lower lumbar discs after 30 min of traction. The increase in the posterior disc height was more apparent than that in the anterior disc height. Conclusions Horizontal traction was evidently effective in increasing the disc height of lower lumbar levels, particularly in the posterior regions of the discs. Further evidence of the effects of traction of different modes, magnitudes, and durations on the change in disc height is required for proper control of traction applied to specific disc levels.

Mechanical effects of traction on lumbar intervertebral discs: A magnetic resonance imaging study.

Study design Biomechanical experiment using an in situ porcine model. Objective To find the effect of traction treatment on annulus microstructure, molecular convection, and cell viability of degraded discs. Summary of background data Spinal traction is a conservative treatment for disc disorders. The recognized biomechanical benefits include disc height recovery, foramen enlargement, and intradiscal pressure reduction. However, the influence of traction treatment on annulus microstructure, molecular transportation, and cell viability of degraded discs has not been fully investigated. Methods A total of 48 thoracic discs were dissected from 8 porcine spines (140 kg, 6-month old) within 4 hours after killing them and then divided into 3 groups: intact, degraded without traction, and degraded with traction. Each disc was incubated in a whole-organ culture system and subjected to diurnal loadings for 7 days. Except for the intact group, discs were degraded with 0.5 mL of trypsin on day 1 and a 5-hour fatigue loading on day 2. From day 4 to day 6, half of the degraded discs received a 30-minute traction treatment per day (traction force: 20 kg; loading: unloading = 30 s: 10 s). By the end of the incubation, the discs were inspected for disc height loss, annulus microstructure, molecular (fluorescein sodium) intensity, and cell viability. Results Collagen fibers were crimped and delaminated, whereas the pores were occluded in the annulus fibrosus of the degraded discs. Molecular transportation and cell viability of the discs decreased after matrix degradation. With traction treatment, straightened collagen fibers increased within the degraded annulus fibrosus, and the annulus pores were less occluded. Both molecular transportation and cell viability increased, but not to the intact level. Conclusion Traction treatment is effective in enhancing nutrition supply and promoting disc cell proliferation of the degraded discs. Level of evidence N/A.

Spinal traction promotes molecular transportation in a simulated degenerative intervertebral disc model.

The objective of this study was to measure intradiscal pressure (IDP) changes in the lower cervical spine during a manual cervical distraction (MCD) procedure. Incisions were made anteriorly, and pressure transducers were inserted into each nucleus at lower cervical discs. Four skilled doctors of chiropractic (DCs) performed MCD procedure on nine specimens in prone position with contacts at C5 or at C6 vertebrae with the headpiece in different positions. IDP changes, traction forces, and manually applied posterior-to-anterior forces were analyzed using descriptive statistics. IDP decreases were observed during MCD procedure at all lower cervical levels C4-C5, C5-C6, and C6-C7. The mean IDP decreases were as high as 168.7 KPa. Mean traction forces were as high as 119.2 N. Posterior-to-anterior forces applied during manual traction were as high as 82.6 N. Intraclinician reliability for IDP decrease was high for all four DCs. While two DCs had high intraclinician reliability for applied traction force, the other two DCs demonstrated only moderate reliability. IDP decreases were greatest during moving flexion and traction. They were progressevely less pronouced with neutral traction, fixed flexion and traction, and generalized traction.

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Intradiscal Pressure Changes during Manual Cervical Distraction: A Cadaveric Study

Background: Cervical pillows are considered to be part of the therapeutic strategy in cervical spondylosis, but there is little or no convincing scientific evidence on the effectiveness of these pillows in relieving pain and disability in these patients. Hence, this study investigated the effects of ergonomic latex pillow in conjunction with routine physiotherapy versus routine physiotherapy alone on disability and pain intensity in patients with cervical spondylosis. Methods: 22 patients with cervical spondylosis in a single-blinded pilot study with a pre/post-test design were randomly assigned to experimental and control groups. Both groups received 12 sessions of physiotherapy for four weeks. In the experimental group, participants were given an ergonomic latex pillow to sleep it for four weeks. Participants in the control group slept on their own usual pillow. All the participants filled out the Neck Disability Index questionnaire, and scored their neck pain intensity on the Numerical Pain Rating Scale before and after the intervention. Changes of variables (pain and disability) within and between groups were compared by Paired T-test and the Independent Sample T-test, respectively via SPSS v.20 (p<0.05). Results: Numerical Pain Rating Scale and Neck Disability Index scores were decreased statistically significant within groups. In the experimental group, neck disability scores were significantly lower than those in the control group (p=0.038). However, pain intensity scores were not significantly different between groups. Conclusion: Ergonomic latex pillows can significantly decrease disability related to neck pain in patients with cervical spondylosis after four weeks.

http://mjiri.iums.ac.ir/article-1-4561-en.pdf

A preliminary study: The effect of ergonomic latex pillow on pain and disability in patients with cervical spondylosis.

Morphologic changes in the cervical neural foramen due to flexion and extension : in vivo imaging study

The insufficient investigations on the changes of spinal structures during traction prevent further exploring the possible therapeutic mechanism of cervical traction. A blind randomized crossover-design study was conducted to quantitatively compare the intervertebral disc spaces between axial and anterior lean cervical traction in sitting position. A total of 96 radiographic images from the baseline measurements, axial and anterior lean tractions in 32 asymptomatic subjects were digitized for further analysis. The intra- and inter-examiner reliabilities for measuring the intervertebral disc spaces were in good ranges (ICCs = 0.928–0.942). With the application of anterior lean traction, the statistical increases were detected both in anterior and in posterior disc spaces compared to the baseline (0.29 mm and 0.24 mm; both P < 0.01) and axial traction (0.16 mm and 0.35 mm; both P < 0.01). The greater intervertebral disc spaces obtained during anterior lean traction might be associated with the more even distribution of traction forces over the anterior and posterior neck structures. The neck extension moment through mandible that generally occurred in the axial traction could be counteracted by the downward force of head weight during anterior lean traction. This study quantitatively demonstrated that anterior lean traction in sitting position provided more intervertebral disc space enlargements in both anterior and posterior aspects than axial traction did. These findings may serve as a therapeutic reference when cervical traction is suggested.

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David Wang

Papers

Comparison of the intervertebral disc spaces between axial and anterior lean cervical traction.