Clinical assessment of manipulation and mobilization of the lumbar spine. A critical review of the literature

The widespread use of manual therapy techniques suggests some degree of success in their application. In this article, I review the applied clinical research on the effectiveness of using manipulation or mobilization of the lumbar spine. The literature reviewed indicates highly equivocal results when the goal of therapy was to decrease pain and increase motion. Because of a high incidence of spontaneous recovery from low back syndromes, performance measures may appear to improve significantly when proper controls are not used. Evaluation of the therapeutic effects of manual therapy is complicated by potentially confounding variables when used with other physical therapy procedures. I discuss the need for further, well-designed studies.     

Force-deformation response of the lumbar spine: a sagittal plane model of posteroanterior manipulation and mobilization

OBJECTIVE: To develop a mathematical model capable of describing the static and dynamic motion response of the lumbar spine to posteroanterior forces. DESIGN: Static, impulsive and oscillatory forces with varying thrust angles and offsets were applied to the model, and the resulting motion responses were compared to experimental data published for spinal mobilization and manipulation of prone-lying subjects. BACKGROUND: Methods are sought to improve understanding of the dynamic force-induced displacement response of the lumbar spine during spinal mobilization and manipulation treatment. METHODS: The thorax, pelvis and five lumbar vertebrae were represented as seven rigid structures and eight flexible joint structures. Flexible joint structures were modeled using spring and damper elements with three displacement degrees-of-freedom (posterior-anterior and axial displacement, and flexion-extension rotation). The resulting 21 degrees-of-freedom lumped parameter model was solved in modal space. RESULTS: The fundamental natural frequency of vibration was 5.24 Hz. Simulations performed using 100 N static and dynamic posteroanterior forces applied to the L3 vertebrae indicated that peak L3 segmental displacements were up to 2.40 mm (impulsive) and 8.23 mm (oscillatory at 2 Hz). Appreciable axial displacements (0.41 mm) and flexion-extension rotations (1.49 degrees ) were also observed for oscillatory forces at L3. The posteroanterior motion response of the lumbar vertebrae was relatively insensitive to both the thrust force angle and thrust force offset, but axial displacements and flexion-extension rotations showed a large change (2-fold or greater) for thrust angles greater than -5 degrees (caudal) in comparison to vertical thrusts. Intersegmental motion responses for static, impulsive and oscillatory loads were more comparable than their segmental counterparts. CONCLUSIONS: The model predicts lumbar segmental and inter-segmental motion responses to manipulative forces that are otherwise difficult to obtain experimentally. RELEVANCE: This study assists clinicians to understand the biomechanics of posteroanterior forces applied to the lumbar spine of prone-lying subjects. Of particular clinical relevance is the finding that greater spinal mobility is possible by targeting specific load-time histories.     

A non-invasive protocol for the determination of lumbar spine mobility

Objective. This article presents a non-invasive protocol for the determination of lumbar spine mobility and compares intersegmental lumbar spinal mobility data from 45 subjects using both radiographic (invasive) and videographic (non-invasive) techniques.

Design. Non-linear mathematical models were developed to transfer skin marker coordinates into corresponding vertebral body positions.

Background. To relate skin surface motion with that of the underlying vertebrae and to enhance the reliability of using the non-invasive technique relied on a model of transformation.

Methods. This set of models was developed by taking the L₄ skinfold, the L₁-S₁ skin distraction, and the non-linear difference between the lumbar spinal profile and the skin profile into consideration. Based on the digitized and model transformed data, the intersegmental joint angles (ISA) and intersegmental joint mobilities (ISM) were calculated and compared.

Results. In this study the non-invasive and invasive coordinate differences ranged from 0.485 to 1.099 cm; the mean ISA differences ranged from 0.29 to 2.08 degrees the mean ISM differences ranged from 0.62 to 1.88 degrees.

Conclusions. With these small differences, the quality of the non-invasive protocol and the application of the transformation model were justified sufficient.     

Radiographic mobility of the lumbar spine and its relation to clinical back motion

A sample of 194 examinees (117 women and 77 men), representative of the population, with a history of low back pain, were examined clinically and radiographed. The angles between vertebrae at the levels of L4-L5 and L5-S1 were measured from the lateral lumbar erect, maximal flexion, and maximal extension views. Average mobility at L4-L5 was 14.5 degrees in women and 13.4 in men, and at L5-S1 11.5 degrees in women and 12.1 in men. Mobility became more restricted with increasing age both in women and men; especially at L4-L5. In women decreased radiographic mobility at L4-L5 was significantly (p = 0.002) correlated with restricted side-bending and rotation found at the physical examination. These correlations were clearly less significant among men. At L5-S1, restricted extension in women but restricted flexion and Schober's test in men were significantly correlated with decreased radiographic mobility.     

Mechanics of the anterior interval of the knee using open dynamic MRI

Background

The anterior interval of the knee has been defined as the space between the infrapatellar fat pad and patellar tendon anteriorly, and the anterior border of the tibia and the transverse meniscal ligament posteriorly. Investigation of the normal kinematics of this region is necessary as we begin to appreciate the significant impact that pathologic processes of the anterior interval have on the knee.

Methods

Non-weight bearing and weight bearing dynamic MRIs of 20 healthy knees were evaluated at 30° intervals from 0° to 120° flexion. The angle subtended by the patellar tendon and the anterior tibia was measured at each interval of flexion by three independent observers. The amount of angular change over each interval of flexion was also evaluated and the differences between the relative weight bearing conditions were statistically evaluated.

Findings

The angle formed by the anterior tibia and the patellar tendon decreases with knee flexion (45.2° (SD 10.1°) at full extension vs. 1.2° (SD 2.1°) at full flexion). The average patellar tendon–tibial angle excursion was significantly reduced with full-weight bearing, 43.1° (SD 11.2°) from 0° to 120° of flexion, compared to non-weight bearing, 30.9° (SD 6.1°) over the same range of motion (P < 0.001). Full-weight bearing decreased the angle excursion by 28% compared to non-weight bearing.

Interpretation

The observed changes in the anterior interval are influenced by multiple factors including load, knee architecture, tendon elasticity and tibio-femoral and patello-femoral kinematics. The impact of load on the mechanics of the anterior interval is most pronounced between 0° and 30° of flexion.     

The effect of posteroanterior mobilisation on sagittal mobility of the lumbar spine

The purpose of this study was to investigate the effect of a posteroanterior central vertebral pressure (PA mobilisation) on sagittal mobility of the lumbar spine in asymptomatic subjects. On 3 separate days an experienced manipulative physiotherapist stood on a force platform and applied a PA mobilisation to L3 spinous process for 2 minutes on 18 female subjects. Prior to this, subjects acted as their own control by lying prone for the same length of time but without receiving mobilisation treatment. The force platform was used to indirectly measure the minimum and maximum peak forces, and the frequency of oscillation of the applied PA mobilisation. A CA-6000 Spine Motion Analyser (SMA) was used to measure lumbar spine flexion and extension before and after the mobilisation and control treatments. Prior to the main experiment, intra-therapist reliability of the SMA was found to be good, with no significant difference (p > 0.05) in flexion or extension range of movement between 3 days of testing and root mean square error (RMSE) values of 7.43 degrees for flexion and 8.6 degrees for extension. The results indicated that a PA mobilisation with a mean maximum force of 92.5 N, amplitude of force oscillation of 9.6 N and a frequency of oscillation of 4.5 Hz had no significant affect (p > 0.05) on sagittal mobility of the lumbar spine in the asymptomatic subject population.     

The time-varying response of the in vivo lumbar spine to dynamic repetitive flexion

OBJECTIVE: To quantify the time-varying stiffness and kinematic responses of the in vivo lumbar spine exposed to dynamic repetitive flexion movements. DESIGN: Changes in in vivo passive lumbar moment-angle relationships were monitored in response to dynamic repetitive flexion. BACKGROUND: While previous in vitro studies have provided conflicting evidence on the effects of repetitive flexion movements on the stiffness of the lumbar spine, no previous studies have quantified the time-varying changes of the in vivo lumbar spine to dynamic repetitive flexion. METHODS: Subjects lifted and lowered a 4.5 kg load over two barriers at a rate of 7 lifts per minute for 1.5 h inducing at least 80% of the lumbar flexion range of motion. Prior to lifting and at 30 min intervals passive moment-angle relationships were obtained by pulling the subject into flexion on a customized frictionless table. RESULTS: Repetitive lifting induced a decreasing stiffness trend after 30 min, followed by a recovery towards initial stiffness levels with further loading. The trends were non-significant for all measures studied. CONCLUSIONS: The results indicate that after 30 min of lifting, creep within the passive tissues may allow workers to exceed their initial range of motion, altering joint mechanics and loading patterns potentially leading to an increased risk of developing low back pain. RELEVANCE: Given the potential for time-varying changes to alter the spine's risk of injury and injury mechanisms, knowledge regarding the stiffness response of the in vivo lumbar spine exposed to repetitive flexion may lead to improved understanding and prevention of work related back pain.     

Intrasession reliability and influence of breathing during clinical assessment of lumbar spine postural control

The aims of this study were to evaluate the influence of breathing when measuring lumbar postural control during a clinical progressive lumbar stabilization test (LST) and to estimate the intrasession reliability of the LST. The lumbar postural control index was calculated by using a biofeedback pressure unit. The LST was performed in two different positions (crook lying and upright) and two respiratory conditions (apnea and breathing) by 20 healthy individuals. The intrasession reliability of the lumbar postural control index of one trial was estimated with intraclass correlation coefficient (ICC) based on an Anova model. The results showed that the lumbar postural control index is similar between testing positions. There is an increase of the lumbar postural control index during breathing compared to the apnea. The reliability of the lumbar postural control index was fair to good (ICC 0.28–0.58). We also found that for the apnea, three trials had to be averaged to attain an ICC of 0.80 for both positions. The results of the present study indicate that the progressive LST can be similarly conducted in either supine or upright posture. Clinicians should be aware of the influence of breathing during LST. However, breathing could also serve as a clinical strategy to challenge lumbar spine postural control and stability during bracing therapeutic exercises.     

Effect of direction of applied mobilization force on the posteroanterior response in the lumbar spine

OBJECTIVE: The purpose of this study was to investigate whether changing the direction of applied force affects measured posteroanterior stiffness and associated pelvic (sacral) and lower thoracic rotations. DESIGN: A repeated measures design was used. SETTING: University biomechanical laboratory. PARTICIPANTS: Twenty-four subjects (14 male, 10 female) with no history of recent low back pain or contraindications to mobilization volunteered for testing. MAIN OUTCOME MEASURE: Posteroanterior stiffness was assessed at vertebral levels L3 and L5 through use of 3 sagittal plane directions of applied force; the directions differed by 10 degrees. The amount of sacral and lower thoracic rotation that occurred during loading between 30 and 100 N was also recorded. RESULTS: A small but significant variation of stiffness with direction of applied force was found. At L3, mean stiffness was greatest when the posteroanterior force was applied in a base direction; it was 11% less when the force was applied 10 degrees more caudad than the base direction and 14% less when the force was applied 10 degrees more cephalad than the base direction. There was no significant effect of direction when the force was applied at L5. Both sacral and thoracic rotations displayed significant variation with direction of force when load was applied at L5, with decreasing rotation as the force was applied in a more caudal direction. CONCLUSION: Posteroanterior stiffness in individuals without back pain is affected by the sagittal plane direction in which the posteroanterior force is applied to the lumbar spine. Remote (thoracic and sacral) movements are also affected by the direction of posteroanterior force. Direction of applied force should therefore be controlled, particularly in the research setting.     

Segmental movements of the spine during treadmill walking with normal speed.

OBJECTIVE: The aim of the present work is to investigate the segmental movement patterns of the spine during normal treadmill gait.DESIGN: The spine movement during treadmill gait of ten healthy subjects (five men and five women) has been investigated using an optoelectronic measuring system.METHODS: The spine was divided into seven segments, from C(7) to S(2). The subjects walked with their normal speed. All data were normalized to per cent of the gait cycle. The normal patterns of the spine segment movements were found in the sagittal and the frontal planes.RESULTS: The behaviour of the spine can be described as the motion of a stiff element with superimposed small, inter-segmental movements. These small inter-segmental movements were found both in the sagittal and the frontal planes.CONCLUSIONS: The small inter-segmental movements could play an important role in the reduction of the energy consumption during gait and in maintenance of the equilibrium. RELEVANCE: Any disability affecting the spine should result in changing spine movement pattern during gait, thus changing the overall gait pattern. Therefore, treatment and rehabilitation should not discard the influence of the spine malfunctioning, regardless of its nature.     

The effect of kyphoplasty parameters on the dynamic load transfer within the lumbar spine considering the response of a bio-realistic spine segment

BackgroundWith an increasing prevalence of osteoporosis, physicians have to optimize treatment of relevant vertebral compression fractures, which have significant impact on the quality of life in the elder population. Retrospective clinical studies suggest that kyphoplasty, despite being a procedure with promising potential, may be related to an increased fracture risk of the adjacent untreated vertebrae.MethodsA bio-realistic model of a lumbar spine is introduced to determine the morbidity of cemented augmentation. The model was verified and validated for the purpose of the study and subjected to a dynamic finite element analysis. Anisotropic bone properties and solid ligamentous tissue were considered along with α time varying loading scenario.FindingsThe yielded results merit high clinical interest. Bi-pedicular filling stimulated a symmetrically developing stress field, thus comparing favourably to uni-pedicular augmentation which resulted in a non-uniform loading of the spine segment. An enslavement of the load transfer was also found to both patient bone mineral density and reinforcement–nucleous pulpous superimposition.InterpretationThe investigation presented refined insight into the dynamic biomechanical response of a reinforced spine segment. The increase in the calculated occurring stresses was considered as non-critical in most cases, suggesting that prevalent fractures are a symptomatic condition of osteoporosis rather than a sequel of efficiently preformed kyphoplasty.     

Inter-examiner reliability of passive assessment of intervertebral motion in the cervical and lumbar spine: a systematic review

A systematic review was conducted to determine inter-examiner reliability of passive assessment of segmental intervertebral motion in the cervical and lumbar spine as well as to explore sources of heterogeneity. Passive assessment of motion is used to decide on treatments for neck and low-back pain patients. Inter-examiner reliability has been a matter of debate, resulting in questions about professional credibility and accountability. A structured search for relevant studies in MEDLINE and CINAHL was followed by extensive reference tracing and hand searching. Studies presenting estimates of reliability for individual motion segments were included. No language restrictions were imposed. Study quality was assessed using criteria derived from the Standards for Reporting of Diagnostic Accuracy (STARD) statement and a quality assessment tool for studies of diagnostic accuracy included in systematic reviews (QUADAS). Study selection, quality assessment, and data extraction were performed by two reviewers independently. Qualitative analyses and additional subgroup analyses were conducted. Nineteen studies were included. Two studies satisfied criteria for external and internal validity, of which one found fair to moderate reliability. Assessment of motion segments C1-C2 and C2-C3 almost consistently reached at least fair reliability. Overall, inter-examiner reliability was poor to fair. However, most studies were found to be of poor methodological quality. We propose explicit recommendations for the conduct and reporting of future research.     

Predictive model of intersegmental mobility of lumbar spine in the sagittal plane from skin markers

This article describes a sagittal motion model that transforms skin marker coordinates into corresponding vertebral body coordinates. Coordinate data were obtained from 45 subjects with radiopaque skin markers over the vertebral spinous processes. Data of 30 subjects were used for model development while data of the other Fifteen subjects were used for model validation. The subjects were subjected to lateral spinal radiographs in positions of neutral, flexion, and extension. The model was developed by taking the non-linear difference between lumbar spinal profile and skin profile, the L₄ skin-fold, and the difference of L₁-S₁ skin distraction into consideration. Regression analysis shows high coefficients of determination (range, 62.43–99.86%; mean, 86.41%) in comparing the estimated position data with the actual data in all vertebral body positions. Based on the estimated coordinates, both the intersegmental joint angles and intersegmental joint mobilities were calculated. The result of this study using the non-invasive protocol and the transformation matrices demonstrated that the intersegmental sagittal motion of lumbar spine can be obtained with error ranged from 0.05 to 0.56 degrees.     

Relative contribution of trunk muscles to the stability of the lumbar spine during isometric exertions

OBJECTIVE: To compare the relative contribution of various trunk muscles to the stability of the lumbar spine. DESIGN: Quantification of spine stability with a biomechanical model. BACKGROUND: Modern low back rehabilitation techniques focus on muscles that stabilize the lumbar spine. However, the relative contribution of various trunk muscles to spine stability is currently unknown. METHODS: Eight male subjects performed isometric exertions in trunk flexion, extension, lateral bending, and axial rotation, and isometric exertions under vertical trunk loading and in a lifting hold. Each isometric trial was repeated three times at 20%, 40%, and 60% of the maximum trunk flexion force or with a load of 0%, 20%, 40%, and 60% of body weight for the latter two exertions. Surface EMG data from 12 major trunk muscles were used in the biomechanical model to estimate stability of the lumbar spine. A simulation of each trial was performed repeatedly with one of the 10 major trunk muscle groups removed from the model. RESULTS: Relative contribution of each muscle to spine stability was significantly affected by the combination of loading magnitude and direction (3-way interaction). None of the removed muscles reduced spine stability by more than 30%. CONCLUSIONS: A single muscle cannot be identified as the most important for the stability of the lumbar spine. Rather, spine stability depends on the relative activation of all trunk muscles and other loading variables. RELEVANCE: This study will improve our understanding of individual trunk muscles' contribution to overall stability of the lumbar spine.