Development of a Novel Technique to Record 3D Intersegmental Angular Kinematics During Dynamic Spine Movements

Effects of abdominal hollowing and bracing on each intervertebral angle during quadruped upper and lower extremity lift: Three-dimensional motion analysis of the spine

To investigate the effects of intentionally minimizing spinal motion and abdominal muscle contractions on intervertebral angles during quadruped upper and lower extremity lift (QULEL). Fifteen healthy men performed the QULEL under four conditions: without any special instructions (basic), with the intention to minimize spinal motion (intentional), with abdominal bracing (bracing), and with abdominal hollowing (hollowing). Each intervertebral angle was calculated from the local coordinate system using the marker data obtained from a motion capture system. Shear moduli, as indicators of the activities of the right transversus abdominis (TrA), internal and external oblique, and rectus abdominis muscles, were assessed using shear wave elastography during QULEL. One-way repeated-measures analysis of variance and multiple comparisons among conditions were used to compare each shear modulus of the abdominal muscle and the changes in thoracic kyphosis (Th1-12), lumbar lordosis (L1-5), and lumbar intervertebral angles from the quadruped position to QULEL. The significance level was set at P < 0.05. Changes in lumbar lordosis and L2/L3 and L3/L4 extension angles were significantly lower under hollowing than under other conditions (effect size ηG2: lumbar lordosis, 0.068; L2/L3, 0.072; L3/L4, 0.043). The change in the L1/L2 extension angle significantly decreased in bracing and hollowing compared with the basic (ηG2 = 0.070). Only the TrA shear modulus significantly increased in bracing and hollowing compared with the basic (ηG2 = 0.146). Abdominal hollowing during the QULEL increased TrA activity and suppressed lumbar extension, except at L4/L5, and may be more effective as a rehabilitation exercise for controlling spinal motion.

The effect of vertebral body tethering on spine range of motion in adolescent idiopathic scoliosis: a pilot study

PURPOSE

Posterior spinal fusion and instrumentation (PSF) and vertebral body tethering (VBT) are corrective surgical techniques used in treating adolescent idiopathic scoliosis (AIS). Comparing the preservation of spine range of motion (ROM) following PSF and VBT for treatment of AIS has yet to be explored. The purpose of this work was to retrospectively compare global spine ROM in adolescents (9-18 years of age) without spine deformity, adolescents with untreated AIS, adolescents having undergone PSF, and adolescents having undergone VBT to gain insight on the effect of VBT on spine motion.

METHODS

Twenty participants were recruited into four groups including Control (n = 6), untreated AIS (n = 5), post-operative PSF (n = 4) and post-operative VBT (n = 5). Three-dimensional kinematics of the spine were collected and analyzed using an intersegmental spine model during constrained forward flexion, right-left lateral bending, and right-left axial twist movements.

RESULTS

The PSF group displayed significantly lower spine ROM than the two non-operative groups during thoracic and total left axial twist (p ≤ 0.048), whereas thoracic and total ROM during right-left lateral bending is almost equally lower in the PSF (p ≤ 0.03) and VBT (p ≤ 0.01) groups when compared to the Control and AIS groups.

CONCLUSION

These results suggest some preservation of spine motion in the transverse plane following VBT. This study provides initial evidence of some potential preservation of spine ROM following VBT; however, further prospective investigation of VBT is needed to assess and confirm these hypotheses.

Stereophotogrammetric approaches to multi-segmental kinematics of the thoracolumbar spine: a systematic review

BACKGROUND

Spine disorders are becoming more prevalent in today's ageing society. Motion abnormalities have been linked to the prevalence and recurrence of these disorders. Various protocols exist to measure thoracolumbar spine motion, but a standard multi-segmental approach is still missing. This study aims to systematically evaluate the literature on stereophotogrammetric motion analysis approaches to quantify thoracolumbar spine kinematics in terms of measurement reliability, suitability of protocols for clinical application and clinical significance of the resulting functional assessment.

METHODS

Electronic databases (PubMed, Scopus and ScienceDirect) were searched until February 2022. Studies published in English, investigating the intersegmental kinematics of the thoracolumbar spine using stereophotogrammetric motion analysis were identified. All information relating to measurement reliability; measurement suitability and clinical significance was extracted from the studies identified.

RESULTS

Seventy-four studies met the inclusion criteria. 33% of the studies reported on the repeatability of their measurement. In terms of suitability, only 35% of protocols were deemed suitable for clinical application. The spinous processes of C7, T3, T6, T12, L1, L3 and L5 were the most widely used landmarks. The spine segment definitions were, however, found to be inconsistent among studies. Activities of daily living were the main tasks performed. Comparable results between protocols are however still missing.

CONCLUSION

The literature to date offers various stereophotogrammetric protocols to quantify the multi-segmental motion of the thoracolumbar spine, without a standard guideline being followed. From a clinical point of view, the approaches are still limited. Further research is needed to define a precise motion analysis protocol in terms of segment definition and clinical relevance.

Influence of Spine-Focused Verbal Instruction on Spine Flexion During Lifting

Lifting with a flexed spine, especially near the end range of motion, has been identified as a potential risk factor for low back injury/pain. Therefore, individuals who develop discomfort from repetitive, prolonged and/or loaded flexed or slouched postures may benefit from a greater awareness of how to control and/or modify their spinal posture to avoid irritating their backs in these situations. This study was therefore designed to test the ability of spine-oriented verbal instructions to reduce intersegmental spine flexion during three lifting tasks. The lifts were first performed without any instructions on lifting technique. An audio recording was then played with instructions to limit bending in the lower back before repeating the lifts. Following the verbal instructions, maximum spine flexion angles significantly (p < 0.05) decreased at intersegmental levels in the lower thoracic and upper lumbar (T8/T9 to L2/L3) regions, but no significant changes were observed at the lower lumbar levels (L3/L4 to L5/S1). Thus, it is concluded that spine-oriented verbal instructions can decrease spine flexion during lifting; however, other cues/instructions may be required to target lower lumbar levels which have been identified as the most prone to injury/pain.

Injury risk-factor differences between two golf swing styles: a biomechanical analysis of the lumbar spine, hip and knee

The golf swing has been associated with mechanical injury risk factors at many joints. One swing, the Minimalist Golf Swing, was hypothesised to reduce lumbar spine, lead hip, and lead knee ranges of motion and peak net joint moments, while affecting swing performance, compared to golfers' existing swings. Existing and MGS swings of 15 golfers with handicaps ranging from +2 to -20 were compared. During MGS downswing, golfers had 18.3% less lumbar spine transverse plane ROM, 40.7 and 41.8% less lead hip sagittal and frontal plane ROM, and 39.2% less lead knee sagittal plane ROM. MGS reduced lead hip extensor, abductor, and internal rotator moments by 17.8, 19.7 and 43%, while lead knee extensor, abductor, adductor and external rotator moments were reduced by 24.1, 26.6, 37 and 68.8% respectively. With MGS, club approach was 2° shallower, path 4° more in-to-out and speed 2 m/s slower. MGS reduced certain joint ROM and moments that are linked to injury risk factors, while influencing club impact factors with varying effect. Most golf injuries are from overuse, so reduced loads per cycle with MGS may extend the healthy life of joints, and permit golfers to play injury-free for more years.

Think about it: Cognitive-motor dual-tasking affects sub-regional spine responses to unexpected trunk perturbations

Cognitive motor interference (CMI) is a psychomotor phenomenon characterized by alterations in kinematic spatial-temporal parameters during concurrent cognitive and motor tasks (i.e. dual-tasking). Previous literature has demonstrated that cognitive-motor dual-tasking induces alterations gait parameters; however, the influence of CMI on spine reflexive motion has yet to be researched. The purpose of this study was to assess the influence of cognitive-motor dual-tasking during unexpected spine loading, in particular focusing on paraspinal muscle responses and spine sub-regional kinematic responses. To do this, the spine was perturbed by unexpectedly dropping a 6.8 kg mass into the participants' hands during cognitive dual-task and control conditions. Intersegmental spine angles, paraspinal muscle onset latencies, baseline activations, and response magnitudes were measured. The results demonstrated that participants experienced greater spine flexion at all intersegmental levels during the cognitive dual-task condition compared to the control condition. Additionally, muscle onset latencies were significantly delayed in three of the four paraspinal muscles studied when performing the cognitive-motor dual-task. These results demonstrate that the additional cognitive load led to delayed muscle activation responses and subsequently greater intersegmental lumbar spine flexion in response to a sudden loading perturbation. This suggests that cognitive-motor dual-tasking may increase the risk of developing an acute spine injury under similar conditions.

Influence of creep deformation on sub-regional lumbar spine motion during manual lifting

Prolonged or repetitive spine flexion induces creep deformation of posterior spine tissues allowing for increased intervertebral motion beyond 'normal' limits, which may influence sub-regional (intersegmental) spine motion during subsequent manual lifting tasks. Using spine skin-surface kinematics, intersegmental lumbar spine motion was recorded over 20 minutes of prolonged static spine flexion and a subsequent manual lifting task (2 lifts every 3 minutes, 30 minutes total) in 14 participants. Results demonstrated that mid to lower lumbar intersegmental levels (i.e. L₂/L₃ to L₄/L₅) experienced the greatest overall creep deformation and range of motion during both prolonged flexion and manual lifting; however, overall range of motion during manual lifting was unaffected. Additionally, creep deformation did not completely recover within 30 minutes. Future work should continue to investigate the influence of this residual creep, as well as how overall creep deformation impacts spine neuromuscular control and stability, and ultimately the development of low back disorders. Practitioner summary: Mid to lower lumbar spine levels (i.e. L₂/L₃ to L₄/L₅) experienced the greatest creep deformation and range of motion during both prolonged flexion and manual lifting. Repeated lifting following prolonged flexion may limit creep recovery; however, overall lifting kinematic motion remained unchanged.

The effect of head and gaze orientation on spine kinematics during forward flexion

Compound, or awkward, spine postures have been suggested as a biomechanical risk factor for low back injury. This experiment investigates the influence of head (i.e. head-on-torso) and gaze (i.e. eye-in-head) orientation on three-dimensional (3D) neck and spine range of motion (ROM) during forward flexion movements. To emulate previous experimental protocols and replicate real-world scenarios, a sample of ten young, healthy males (mean ± standard deviation: age: 20.8 ± 1.03 years, height: 180.2 ± 7.36 cm, and mass: 81.9 ± 6.47 kg) completed forward flexion movements with a constrained and unconstrained pelvis, respectively. Surface kinematics were gathered from the head and spine (C₇-S₁). Movements were completed under a baseline condition as well as upward, downward, leftward, and rightward head and gaze orientations. For each condition, mean neck angle and inter-segmental spine (C₇T₁ through L₅S₁) ROM were evaluated. The results demonstrate that directed head and gaze orientations can influence the ROM of specific spine regions during a forward flexion task. With leftward and rightward directed head and gaze orientations, the neck became increasingly twisted and superior thoracic segments (i.e. C₇T₁-T₂T₃) were significantly more twisted during the leftward head orientation condition than the baseline condition. With upward and downward directed head and gaze orientations, a similar effect was observed for neck and superior thoracic (i.e. C₇T₁-T₄T₅) flexion-extension. Interestingly, it was also demonstrated that changes in upward/downward head orientation can also change flexion-extension kinematics of the thoracolumbar region as well (i.e. T₇T₈-L₁L₂), suggesting that head postures requiring neck extension may also promote extension throughout these spine regions. These findings provide evidence for a functional link between changes in neck flexion-extension posture and flexion-extension movement of the thoracolumbar region of the spine.

Characterizing Local Dynamic Stability of Lumbar Spine Sub-regions During Repetitive Trunk Flexion-Extension Movements

Using a technique of tracking intersegmental spine kinematics via skin surface markers, this study aimed to estimate local dynamic spine stability across smaller sub-regions (or segments) of the lumbar spine while also considering the impact of an external pelvic constraint during repetitive movements. Sixteen participants (10 males) performed two trials [Free Motion (FM), Pelvis Constrained (PC)] each consisting of 65 repetitive trunk flexion-extension movements to assess dynamic spine stability using maximum Lyapunov exponents (LyE). First, results indicated that LyE obtained from analysis of 30 repetitive flexion-extension movements did not differ from those obtained from analysis of greater numbers of repetitive movements, which aligns with results from a previous study for the whole lumbar spine. Next, for both males and females, and FM and PC trials, the most caudal region of the lumbar spine behaved the most dynamically stable, while upper lumbar regions behaved the most dynamically unstable. Finally, females demonstrated greater lumbar and intersegmental stability (lower LyE) during PC trials compared to FM, while males demonstrated slightly decreased lumbar and intersegmental stability (higher LyE) during PC trials compared to FM; this resulted in PC trials, but not FM trials, being different between sexes. Altogether, these data show that dynamic stability of lumbar spine sub-regions may be related to the proximity of the motion segment to rigid skeletal structures, and that consideration is needed when deciding whether to constrain the pelvis during analyses of dynamic spine stability.

Discriminating spatiotemporal movement strategies during spine flexion-extension in healthy individuals

BACKGROUND CONTEXT

The spine is an anatomically complex system with numerous degrees of freedom. Due to this anatomical complexity, it is likely that multiple motor control options exist to complete a given task.

PURPOSE

To identify if distinct spine spatiotemporal movement strategies are utilized in a homogenous sample of young healthy participants.

STUDY DESIGN

Kinematic data were captured from a single cohort of male participants (N=51) during a simple, self-controlled spine flexion-extension task.

METHODS

Thoracic and lumbar flexion-extension data were analyzed to extract the continuous relative phase between each spine subsection. Continuous relative phase data were evaluated using a principal component analysis to identify major sources of variation in spine movement coordination. Unsupervised machine learning (k-means clustering) was used to identify distinct clusters present within the healthy participants sampled. Once distinguished, intersegmental spine kinematics were compared amongst clusters.

RESULTS

The findings of the current work suggest that there are distinct timing strategies that are utilized, within the participants sampled, to control spine flexion-extension movement. These strategies differentiate the sequencing of intersegmental movement and are not discriminable on the basis of simple participant demographic characteristics (ie, age, height, and body mass index), total movement time or range of motion.

CONCLUSIONS

Spatiotemporal spine flexion-extension patterns are not uniform across a population of young healthy individuals.

CLINICAL SIGNIFICANCE

Future work needs to identify whether the motor patterns characterized with this work are driven by distinct neuromuscular activation patterns, and if each given pattern has a varied risk for low back injury.

Distinguishing between typical and atypical motion patterns amongst healthy individuals during a constrained spine flexion task

Despite 'abnormal' motion being considered a risk factor for low back injury, the current understanding of 'normal' spine motion is limited. Identifying normal motion within an individual is complicated by the considerable variation in movement patterns amongst healthy individuals. Therefore, the purpose of this study was to characterize sources of variation in spine motion among a sample of healthy participants. The second objective of this study was to develop a multivariate model capable of predicting an expected movement pattern for an individual. The kinematic shape of the lower thoracic and lumbar spine was recorded during a constrained dynamic trunk flexion movement; as this is not a normal everyday movement task, movements are considered 'typical' and 'atypical' for this task rather than 'normal' and 'abnormal'. Variations in neutral standing posture accounted for 85% of the variation in spine motion throughout the task. Differences in total spine range of flexion and a regional re-weighting of range of motion between lower thoracic and lumbar regions explained a further 9% of the variance among individuals. The analysis also highlighted a difference in temporal sequencing of motion between lower thoracic and lumbar regions which explained 2% of the total movement variation. These identified sources of variation were used to select independent variables for a multivariate linear model capable of predicting an individuals' expected movement pattern. This was done as a proof-of-concept to demonstrate how the error between predicted and observed motion patterns could be used to differentiate between 'typical' and 'atypical' movement strategies.

Tactile Feedback can be Used to Redistribute Flexion Motion Across Spine Motion Segments

This experiment investigates the efficacy of tactile feedback in affecting changes to dynamic spine movements. A sample of (n = 24) young, healthy males were assessed while completing targeted spine flexion movements with instruction to minimize stretching of the skin beneath an applied tactile stimulus (liquid bandage). Localized tactile stimuli were placed bilaterally at either lumbar (L4), lower thoracic (T10) or upper thoracic (T4) levels. Results demonstrate that localized tactile feedback elicited a re-distribution of spine flexion movement across spine sub-sections (e.g. lumbar vs. thoracic) and intervertebral segments (e.g. C7/T1 through L5/S1). Further, tactile feedback successfully limited the magnitude of end-range flexion, but did not limit functional mid-range spine flexion. Finally, tactile feedback located in the lower thoracic region (T10) increased thoracic flexion variability; however, tactile feedback located at the T4 and L4 regions had no significant effect on movement variability. These findings provide evidence that spine neuromuscular control patterns can be altered using simple tactile stimuli. In terms of low back injury prevention and/or rehabilitation, the tactile feedback investigated here has apparent utility in limiting recognized mechanical risk factors for low back injury; specifically, the local incidence of flexion at specific spine levels, and the incidence of end-range flexion.