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Impairments of cervico-cephalic kinaesthesia and habitual forward head posture have been considered important in the aetiology of postural neck pain, yet these factors have not been specifically examined in a homogeneous clinical population. The objective of this study was to compare the habitual sitting posture (HSP), perception of good posture and postural repositioning error (PRE) of the cervico-thoracic (CT) spine in individuals with postural neck pain, with a matched group of asymptomatic subjects. Twenty-one subjects with postural neck pain and 22 asymptomatic control subjects were recruited into the study. An optical motion analysis system was used to measure the HSP and perceived 'good' sitting posture. PRE was measured over six trials where the subject attempted to replicate their self-selected 'good' posture. There was no difference between the groups in the HSP but significant differences were identified in the perception of 'good' posture. Posture repositioning error was higher for the head posture variables than for CT and shoulder girdle variables in both groups. However, there was no significant difference in posture repositioning error between groups for any of the posture measures. The findings suggest that individuals with postural neck pain may have a different perception of 'good' posture, but no significant difference in HSP or kinaesthetic sensibility compared with matched asymptomatic subjects. [ABSTRACT FROM AUTHOR]

Although a consistent pattern of ipsilateral movement coupling between cervical spine rotation and lateral flexion has been widely described, variability in these movement patterns has not been reported. In 30 asymptomatic subjects, the ranges of primary and coupled movements were determined in the neutral posture, and in the extremes of cervical spine protraction and retraction. All measurements were performed using the SpinT three-dimensional goniometer for which excellent intra-tester reliability was demonstrated for both primary (ICC(3,1) 0.93-0.98) and coupled (ICC(3,1) 0.76-0.98) movements. The ranges of primary and coupled movements changed significantly when movement was initiated from the end-range postures (P < 0.001). In the neutral posture, approximately 70% of subjects demonstrated an ipsilateral pattern of coupled movement. During cervical rotation, the dominant coupling pattern seen in neutral was no longer retained in retraction, while the protracted posture had a greater influence on the coupled movements accompanying primary lateral flexion. The concept of a stereotypical pattern of cervical spine movement coupling is not supported by these results. The posture in which movements are initiated appears to have a significant influence on the three-dimensional kinematics of the cervical spine. [ABSTRACT FROM AUTHOR]

In this article, the author discusses the association of neck pain to head postures. The author states that not all patients with posture related-neck pain have similar postural changes. He mentions that the factors that influence neck pain include postural adjustment, level of muscle activity, and understanding and views on good posture. He says that environmental and work-related factors may also serve as aetiological factors for posture-related neck pain.

Background: Lower limb muscle power is emerging as an important determinant of patient function after knee injury or surgery. This study tested proof of concept of a cycle sprint test for the evaluation of lower limb muscle power, as an outcome measure for patients having total knee arthroplasty (TKA)., Methods: Thirty-two patients were enrolled, of which 16 completed all follow-ups (3, 6, and 12 months). All patients completed the Oxford Knee Score and Knee Injury and Osteoarthritis Outcome Score questionnaires, a 10-m walk test, and 30-second sit-stand test. A trainer-mounted road cycle fitted with an instrumented crank was used for the cycle sprint test. Maximum muscle power was measured from 3, 10-second maximal efforts., Results: Significant improvements in Oxford Knee Score and Knee Injury and Osteoarthritis Outcome scores relative to baseline were achieved at each follow-up ( P < .001), and functional test performance improved significantly at 6 and 12 months ( P < .001). Compared with the baseline of 268W, muscle power was significantly lower at 3 months (239W, -13%, P < .05) and significantly higher at 12 months (308W, +12%, P < .05)., Conclusion: The concept of muscle power measurement using a cycle sprint test before and after TKA has been demonstrated in this study. Identification of individuals with lower limb muscle power deficits after TKA may inform rehabilitation programs and enhance long-term outcomes., (© 2021 The Authors.)

Background: To determine the effect of mobilization on the day of surgery on the readiness for discharge and length of stay after elective total hip arthroplasty (THA)., Methods: We devised a randomized control trial with concealed allocation and intention-to-treat analysis. Overall, 126 patients who underwent THA and met the criteria for mobilization on the day of surgery were randomly allocated into 2 groups; the intervention group was mobilized on the day of surgery, n = 58 and the control group was mobilized on the day after surgery, n = 68. Apart from timing of mobilization, both groups received the same postoperative management. The primary outcome measures were length of hospital stay and time to readiness for discharge., Results: The early mobilization group was ready for discharge 63 hours (standard deviation [SD] = 15 hours) after surgery, compared to 70 hours (SD = 18 hours) for the control group (P = .03, 95% CI, 0.7-12.8). There was no significant difference in hospital stay in the early mobilization group (77 hours [SD = 30 hours]), compared to the control group (87 hours [SD = 35 hours]; P = .11, 95% CI, -2.1 to 21.6). Despite this at any point in time after the surgery, the intervention group was 1.8 times (P = .003, 95% CI, = 1.2-2.7) more likely to have been discharged., Conclusion: Mobilization on the day of THA surgery significantly increases the probability of discharge at any singular point in time compared with mobilization on the day after surgery and decreases the time to readiness for discharge., (Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.)

Background: In recent years, new models of health service delivery in orthopaedic outpatient clinics, including physiotherapists working in orthopaedic triage roles, have become increasingly common. Evaluation of patient satisfaction with orthopaedic clinic services is dependent on an understanding of factors influencing patient satisfaction in this clinical context., Objectives: The objective of this study was to identify the factors influencing patient satisfaction with orthopaedic outpatient clinic services., Study Design: A cross-sectional, qualitative design including focus groups and interviews., Methods: Interviews and focus group sessions were undertaken with 36 participants representing patients, health professionals and clinical support staff in an orthopaedic outpatient clinic. Interviews and focus groups provided a rich narrative which was subjected to a process of thematic analysis., Results: The analysis identified seven themes influencing patient satisfaction with orthopaedic clinic assessment. These themes were clinic waiting time, clinical contact time, trust, empathy, communication, expectation and relatedness., Conclusions: Understanding factors influencing patient satisfaction is important to inform organisational and clinical processes that aim to foster high levels of patient satisfaction. Clinician awareness of the interpersonal issues which dominate stakeholders' perspectives of patient satisfaction may improve the patient experience and potentially foster patient behaviours toward a therapeutic advantage. An understanding of these factors in the context of orthopaedic clinics is also important in the development of questionnaires designed to evaluate patient satisfaction with health service delivery., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Introduction: Individuals with Huntington's disease have a high prevalence of falls, but the specific factors that may increase the risk of falling have not been clearly identified in this clinical population. This study aimed to identify the characteristics of individuals with early to mid-stage Huntington's disease who had a history of falls, compared with a cohort with no history of falls., Methods: Twenty-four participants (10 non-fallers and 14 recurrent fallers) with a diagnosis of early to mid-stage Huntington's disease were included in this study. Falls data were collected using retrospective survey analysis. Participants were assessed using measures of balance (Berg Balance Scale), mobility (Rivermead mobility index [RMI]), fear of falling (Activity-specific Balance Confidence Scale) and gait (6-min walk test; 10-m walk test self-paced and dual tasking)., Results: There was no difference in severity of disease state between fallers (Unified Huntington Disease Rating Scale [UHDRS] motor 25.33) and non-fallers (UHDRS motor 25.13) (p = 0.97). The prevalence of falls was high with 66.7% of participants reporting at least one fall and 58.3% reporting two or more falls in the past 12 months. There was no difference in age or gender between recurrent fallers and non-fallers. Recurrent fallers had significantly lower scores on the Activity-specific Balance Confidence Scale (p < 0.01) and the RMI (p < 0.05). The probability of falling increases rapidly with a RMI score of less than 10., Discussion: Recurrent falls are common in people with Huntington's disease. Individuals with a history of falls were found to have a greater fear of falling and lower functional mobility performance than those who did not have a history of falls. These measures may be useful in the identification of individuals with Huntington's disease who might benefit from a falls prevention programme. Copyright © 2014 John Wiley & Sons, Ltd., (Copyright © 2014 John Wiley & Sons, Ltd.)

Study Design: Single-cohort laboratory-based study., Objectives: To measure thoracic spine extension motion during bilateral arm elevation using functional radiography and photographic image analysis., Background: Impairment of thoracic spine extension motion may impact shoulder girdle function. Motion of the thoracic spine during arm movement has not been directly measured using functional radiographic analysis., Methods: In 21 asymptomatic men, thoracic kyphosis was measured in neutral standing and in end-range bilateral arm elevation, using lateral radiographs and photographic image analysis. Using both measurement techniques, the difference in thoracic kyphosis between the 2 body positions was used to quantify the range of extension motion of the thoracic spine. Bland-Altman plots were used to examine the agreement between measurement techniques. The relationship between the amount of thoracic kyphosis in neutral standing and kyphosis in full bilateral arm elevation was also examined., Results: The mean ± SD increase in thoracic extension with bilateral arm elevation was 12.8° ± 7.6° and 10.5° ± 4.4°, when measured from the radiographs and photographs, respectively. There was a significant correlation between the radiographic and photographic measurements of the amount of thoracic kyphosis measured in neutral posture (r = 0.71, P<.01) and for the kyphosis measured in full bilateral arm elevation (r = 0.79, P<.001). The mean difference between the 2 measurement techniques was 2.1° for kyphosis measured in neutral posture and 0.5° when measured in full bilateral arm elevation. The thoracic kyphosis angle measured in neutral posture was strongly correlated with the thoracic kyphosis angle measured in full bilateral arm elevation when measured with both radiographic (r = 0.80, P<.001) and photographic (r = 0.84, P<.001) techniques., Conclusion: In asymptomatic men, bilateral arm elevation is associated with movement of the thoracic spine toward extension, but the amount of movement is variable among individuals.

Objective: The purposes of this study were to examine the range of thoracic spine extension motion in a group of young, asymptomatic subjects and compare the radiologically derived measurements with those obtained using photographic analysis, and to examine the relationship between the magnitude of the neutral thoracic kyphosis and the range of thoracic spine extension motion., Methods: In 14 asymptomatic male subjects (mean age ± SD, 30.2 ± 7 years), the thoracic kyphosis in standing and full thoracic spine extension was measured from lateral thoracic spine radiographs and digital photographs. The difference between the 2 measurements was used to define the range of thoracic extension motion., Results: The range of thoracic extension motion measured radiologically was between 0 and 26° (mean ± SD, 12.0° ± 8.9°), whereas the photographic range was between 8° and 23° (mean ± SD, 12.4° ± 4.1°). There was a significant correlation between the photographic and radiographic measurements of extension range (r = 0.69, P < .01). Extension range of motion measured radiologically was significantly correlated with the magnitude of the thoracic kyphosis (r = 0.71, P < .01)., Conclusion: Functional radiographs of the thoracic spine can be used to measure the extension range of motion and define the extreme of range. The range of thoracic extension motion may be influenced by the magnitude of the neutral kyphosis. This technique may be used in future studies to evaluate the impact of spinal disorders on thoracic spine mobility., (Copyright © 2012 National University of Health Sciences. Published by Mosby, Inc. All rights reserved.)

Study Design: Cross-sectional study., Objectives: To examine extension mobility of the thoracic spine in young, asymptomatic adults, with particular reference to the influence of subject position and magnitude of the thoracic kyphosis., Background: Impairment of thoracic extension motion is commonly associated with mechanical pain disorders in this region of the spine. Knowledge of normal thoracic mobility and the factors that may influence this motion is important in the evaluation and management of thoracic pain disorders., Methods: In 40 asymptomatic adults, the total and regional thoracic extension range of motion was measured using 2-dimensional photographic image analysis. Extension mobility was measured in standing, sitting, prone, and 4-point kneeling. The association between the magnitude of the habitual thoracic kyphosis and extension mobility was also examined., Results: When measured from the habitual standing position, the mean range of flexion was 11.5° (3.7°) and mean extension range was 8.7° (3.7°). Thoracic extension was significantly greater in unloaded positions compared to loaded positions (P<.001). The standing thoracic kyphosis angle was significantly correlated with the end range thoracic extension angle in all positions (r = 0.63-0.79, P<.001). There was a poor correlation between the thoracic kyphosis angle and thoracic extension range of motion in all positions (r = 0.11-0.34, P>.06)., Conclusion: When measured from the habitual standing position, thoracic extension range of motion in young individuals is small and poorly correlated with the magnitude of the standing thoracic kyphosis. Unloaded positions (4-point kneeling and prone), compared to positions that load the spine (standing and sitting), appear to promote a greater range of thoracic extension motion.

The influence of whole body sitting posture on cervico-thoracic posture, mechanical load and extensor muscle activity was examined in 23 asymptomatic adults. Cervical and upper thoracic extensor muscle activity measured in guided slouched and lumbo-pelvic neutral postures was normalised to that measured in a self-selected habitual posture. Head and neck posture and gravitational load moment measurements were obtained in each posture. Sagittal head translation, upper cervical extension and load moment were significantly greater in the slouched posture (p < 0.001). Contrasting patterns of cervical and thoracic extensor activity were observed in the slouched and neutral postures, with cervical extensor activity 40% higher in the slouched posture (p < 0.0001). Thoracic extensor activity was significantly higher in the lumbo-pelvic neutral posture than the habitual posture (p = 0.002). The significant changes in extensor muscle activity with postural modification appear to be induced by the associated change in mechanical load moment of the head. STATEMENT OF RELEVANCE: More neutral sitting postures reduce the demand on the cervical extensor muscles and modify the relative contribution of cervical and thoracic extensors to the control of head and neck posture. Postures that promote these patterns of muscular activity may reduce cervical spine loading and the development of posture-related neck pain.

The purpose of this study was to evaluate the construct and content validity of the Neck Disability Index (NDI) and the Neck Pain and Disability Scale (NPAD) in patients with chronic, non-traumatic neck pain. Twenty patients (mean age=64.5 years) completed a patient-specific questionnaire, the Problem Elicitation Technique (PET), followed by the NDI and NPAD. Content validity was assessed by comparing the items of the NDI and NPAD with problems identified from the PET. Construct validity of the fixed-item questionnaires was examined by establishing the correlation with each other, and with the PET score. Eleven common problems were identified by patients through the PET, of which six were included in the NDI and seven included in the NPAD. The NDI and NPAD scores were strongly correlated (r=0.86, p<0.01), while the correlation between the PET and the fixed-item questionnaires was moderate (NDI: r=0.62, p<0.01; NPAD: r=0.71, p<0.01). Both the NDI and the NPAD include most of the functional problems common to this patient group, and display good content validity. The PET is better able to evaluate the problems specific to the individual patient and is therefore measuring a somewhat different construct to the fixed-item questionnaires.

Objective: The purpose of this study was to determine the reliability of 3 isometric muscle endurance tests in subjects with postural neck pain., Methods: Twenty-one subjects with chronic postural neck pain performed 3 submaximal muscle tests twice on the first occasion and once at the second session 3 days later. The tests examined isometric neck flexion, neck extension, and scapular muscle endurance., Results: Reliability was excellent for the neck flexor test (intraclass correlation coefficient [ICC] = 0 93), moderate for the scapular test (ICC = 0.67), and good for the neck extensor test (ICC = 0 88). The standard error of measure for the tests was 6.4, 10.9, and 25.9 seconds, respectively. The minimum change required to represent real change in muscle endurance was 17.8 seconds for the neck flexor test, 30.1 seconds for the scapular test, and 71.3 seconds for the neck extensor test., Conclusion: This study showed the reliability of 3 cervical spine and shoulder girdle submaximal muscle endurance tests in patients with postural neck pain.

Objective: This study examines the influence of posture on the range of axial rotation of the thorax and the range and direction of the coupled lateral flexion., Methods: The ranges of mid thoracic axial rotation and coupled lateral flexion were measured in 52 asymptomatic subjects (aged 18-43 years) using an optical motion analysis system. To examine the influence of posture on primary and coupled motion, we initiated axial rotation from a neutral sitting posture and from end-range thoracic flexion and extension., Results: There was a significant decrease in the range of thoracic rotation in flexion compared with the neutral and extended postures (P < .001). The mean range of coupled lateral flexion was 8.9% of the axial rotation range in the neutral posture and increased to 14.3% and 23.2% in the extended and flexed postures, respectively. Patterns of coupled motion varied between subjects, but an ipsilateral pattern was more common in the flexed posture, whereas a contralateral pattern was more common in the neutral and extended postures., Conclusions: The ranges and patterns of coupled motion of the thorax appear to be strongly influenced by the posture from which the movement is initiated. This has important implications in relation to the interpretation of clinical tests of thoracic motion and in consideration of mechanisms of development of thoracic pain disorders.

Study Design: Prospective cohort study., Objectives: To classify patients with nonacute, nontraumatic neck pain according to the dominant impairment of spinal function, and to determine whether there were differences in the amount of treatment sessions required (treatment dose) to achieve a significant change in the patients disorder., Background: Classification of patients with mechanical neck pain may be an important process in optimizing treatment prescription and evaluating treatment response. However, patient classification has not been used to consider possible differences in the amount of treatment sessions (treatment dose) required to achieve a significant change in the neck pain disorder., Methods and Measures: Ninety-two patients with nonacute, nontraumatic neck pain were classified into 2 groups, according to the dominant impairment of spinal function. Of the 77 patients who completed treatment, 63 (82%) were classified as having a "movement disorder," while the remainder was classified into a "loading disorder" group. Physical therapists who were blinded to the patient classification provided multimodal physical therapy treatment as considered appropriate and the patients were discharged when the optimal treatment response had been achieved., Results: There was no difference in pain intensity or global disability level between the groups at baseline. Both groups achieved a significant improvement in neck pain and disability following treatment, and there was no significant difference between groups in the magnitude of the treatment response. The number of treatment sessions received by the loading group (mean +/- SD, 7.3 +/- 4.5) was significantly lower than the number received by the movement group (mean +/- SD, 11.5 +/- 5.9; 95% CI: -7.6 to -0.8; P<.01). Patients in the loading group were 2.4 times as likely to be discharged at any particular treatment session (95% CI: 1.1 to 4.1, P<.005) compared to those in the movement group., Conclusion: For patients with nontraumatic neck pain, classification according to impairment of spinal function may be a useful indicator of the number of physical therapy treatment sessions required to achieve a significant treatment response.

Human thoracic discs were analyzed for collagen and collagen cross-links to determine the distribution due to segmental, age, and gender influences. Thoracic discs from 26 cadaveric spines (1 to 90 years old) were graded macroscopically, then separated into anular and nuclear samples. Only grade I (i.e., normal) disc samples were selected (n=209). Pyridinoline and deoxypyridinoline cross-links were initially separated by column chromatography and analyzed by reverse-phase high-pressure liquid chromatography. The collagen content was lower and the extent of pyridinoline and deoxypyridinoline were significantly higher in the nucleus compared with the anulus (p <.001). The collagen content and extent of pyridinoline were significantly lower with increasing age in the anulus and nucleus (p <.001). Young male discs had a significantly higher extent of pyridinoline compared with females (p <.001). Age, gender, and disc region differences were found to have a significant influence on the biochemical composition of the normal disc extracellular matrix.

There are limited data detailing the pattern of age and gender-related changes to the thoracic vertebral bodies and intervertebral discs. A retrospective MR investigation, involving T1-weighted midsagittal images from 169 cases, was undertaken to examine age influences on the anterior wedge (anteroposterior height ratio or Ha/Hp), biconcavity (midposterior height ratio or Hm/Hp), and compression indices (posterior height/anteroposterior diameter or Hp/D) of the thoracic vertebral bodies. Disc degenerative changes in the annulus, nucleus, end-plate and disc margin were noted on T2-weighted sagittal images for the 169 cases, based on a 3-level grading system. A linear age-related decline in the Ha/Hp and Hm/Hp indices was noted. The Hp/D index increased during the first few decades of life, then decreased gradually thereafter. The prevalence of abnormal findings in the annuli, nuclei and disc margins increased with increasing age, particularly in the mid and lower thoracic discs. Greater disc degenerative changes were observed in males. These findings provide further insight into the nature of thoracic vertebral shape changes across the lifespan, and the typical patterns of degeneration of the thoracic intervertebral discs.

Flexion and extension movements or positions have been advocated in the treatment of various forms of low back dysfunction due to the potential pain relieving effects attributed to displacements of the intervertebral disc (IVD). Objective in vivo determination of the segmental behaviour of the disc to contrasting positions has until recently been difficult. Magnetic resonance imaging (MRI) was used in this study to evaluate the influence of sagittal plane positions on lumbar IVD height and nucleus displacement in a small asymptomatic population.T2-weighted sagittal plane images from L1 to S1 were obtained from 10 subjects (mean age: 30+/-5 years) positioned supine in lumbar flexion, followed by extension. Changes in disc height and localization of nucleus position (determined by peak MRI signal intensity) between the two positions were calculated. Discs were classified for degenerative changes using a semi-quantitative grading scale. The mean range of lumbar sagittal movement achieved in the MRI was 44 degrees (range: 22-77 degrees ). Between flexion and extension, a significant increase in measured anterior disc height of 1.1 mm (P<0.0001) and anterior displacement of the nucleus of 6.7% (P<0.0001) was observed. Despite the anterior displacement of the nucleus in extension observed in the pooled analysis, 30% of discs did not follow this trend. Nucleus degeneration was observed in at least one disc in nine subjects and in 26% of all discs examined. Lumbar spine position was found to be associated with small measured changes in anterior disc height and nucleus position, however, this response was variable within and between individuals. The theoretical concept of a stereotypical effect of spinal position on the lumbar IVD is challenged by these initial data. Since the health of the disc is often unknown in clinical practice, manual therapy treatment for lumbar spine pain should be based on the symptomatic response to movement and position rather than biomechanical theory., (Copyright 2000 Harcourt Publishers Ltd.)

Evaluation of the movement response to posteroanterior (PA) loads applied to the spinous processes is a recognized part of the physical examination of the thoracic spine. During this clinical procedure the thoracic spine is supported by the ribcage which may contribute to the movement response. However, the contribution of ribcage stiffness to the PA stiffness of the thoracic spine has not been established. The purpose of this study was to measure the PA stiffness of the thoracic spine and compare this to the stiffness of the ribcage under anteroposterior load. Using force-displacement analysis, this study measured the PA stiffness of the thoracic spine at T4, T7 and T10 in 20 asymptomatic individuals, and compared this to the ribcage stiffness measured through sternal compression. The mean PA stiffness at T7 (10.7 N/mm) was significantly greater than at T4 (9.1 N/mm, P < 0.001), and there was a non-significant increase between T7 and T10 (11.4 N/mm, P = 0.08). The stiffness of the ribcage measured via sternal compression (7.6 N/mm) was significantly lower than the thoracic PA stiffness at all levels (P < 0.01). A significant proportion (33%) of the thoracic spine PA stiffness was accounted for by the stiffness of the ribcage (P < 0.01). In young, asymptomatic subjects, the PA stiffness of the thoracic spine is significantly greater than the stiffness of the ribcage. This suggests that the response to PA load application in the thoracic spine can be attributed to factors relating to the spine as well as the ribcage. Defining consistent patterns of PA stiffness in the thoracic spine may assist in the interpretation of clinical measurements of patients with mechanical dysfunction of the thoracic spine.

Morphometric X-ray absorptiometry (MXA) offers some potential advantages over spinal radiography for the quantitative evaluation of vertebral fractures in individuals with spinal osteoporosis. This ex vivo study examined the accuracy of MXA and quantitative morphometry (QM) for the evaluation of vertebral height, in relation to direct measurements from cadaveric vertebral columns. Spinal radiographs and MXA scans were obtained from nine cadaveric vertebral columns (mean age at death 64 years). Anterior, middle and posterior vertebral body heights of all segments from T4 to L4 were measured interactively using MXA software and QM (from the spinal radiographs), and compared with direct measurements derived using digital callipers following cadaveric dissection. Coefficients of variation for repeat QM and MXA scan analysis were less than 2%. The QM and MXA measurements were both strongly correlated (r(2) = 0.99) with the direct measurements, with accuracy errors of between 2.6% and 4.3%, and 4.5% and 4.8%, for QM and MXA respectively. At the three measurement sites, analysis of measurement differences showed that QM tended to overestimate the true height and MXA tended towards under-estimation. The mean difference between the direct measurements and QM measurements ranged from 2.7% to 8.7%, and the mean difference between direct and MXA measurements ranged from -2. 9% to 4.1%. There was strong linear association between the MXA and QM measurements (r(2) = 0.99) with mean differences at the three measurement sites ranging from -4.1% to -5.9%. Under the optimal (ex vivo) scanning conditions used in this study, MXA is comparable to spinal radiography for the assessment of vertebral height. Further studies are required to determine the conditions under which satisfactory MXA image resolution and measurement accuracy can be achieved in a clinical population.

Objective: To compare the posteroanterior (PA) stiffness of the lumbar spine when the load is applied in a vertical direction with the stiffness when the load is applied perpendicular to the spinal curve., Design: The PA stiffness of the lumbar spine was assessed at L1, L3 and L5 on 24 normal subjects using a mechanical spinal mobilization apparatus. The PA stiffness was measured when the load was applied in a vertical direction and when the load was applied perpendicular to the spinal curve at the level being tested., Setting: A university biomechanics laboratory., Design: A repeated-measures design with pseudorandomization of the order of testing., Main Outcome Measures: Stiffness variable derived from force-displacement curve., Results: The difference in PA stiffness between the two loading conditions was small at all three levels tested. The stiffness of L5 was significantly lower when the load was applied in the vertical direction compared with the application of the load in the perpendicular direction (p = .0001). Altering the angle of inclination of PA load had no statistically significant effect on PA stiffness at L1 and L3. The mean PA stiffness of the lumbar spine increased in a caudal direction (L1 = 10.4 N/mm, L3 = 11.4 N/mm, L5 = 11.6 N/mm)., Conclusion: The orientation of the PA load had only a small effect on the measured PA stiffness and would be unlikely to be detected during manual examination of the spine. However, changes in the orientation of the PA load may be important when considered in relation to the symptom response.

SUMMARY. Physiotherapists commonly use motion testing techniques in the assessment of patients with spinal disorders. One of the techniques considered important in the assessment of low back pain is the application of posteroanterior (PA) forces to the lumbar spinous processes to evaluate spinal stiffness and symptom response. The purpose of this study was to investigate the effect of spinal position on the measured lumbar PA stiffness. The PA stiffness at the L3 and L5 vertebral levels was assessed in 12 painfree subjects in three prone lying positions (flexion, neutral and extension). PA forces were applied to the spinous processes, under quasi-static loading conditions, using a specifically built apparatus. The stiffness coefficient was calculated from the slope of the regression line fitted to the truncated (35N-80N) force-displacement curves. At both vertebral levels, the PA stiffness was position dependent, with the lowest values obtained in the neutral position. The mean stiffness increased by 12.4% in extension and 31.9% in flexion. In all positions PA stiffness was significantly greater at L5 than at L3. These results suggest that clinical assessments of lumbar PA stiffness may be influenced by the patient position in which the test is performed. Comparative assessments of PA stiffness over time should be performed with the spine supported in the same position. Copyright 1998 Harcourt Publishers Ltd.

SUMMARY. Interactions between thoracic spine posture and mobility are believed to play a role in the development of spinal pain syndromes. Accordingly, appropriate and effective manual therapy management is dependent on a sound knowledge of the anatomy and biomechanics of this region of the vertebral column. This paper reviews the primary anatomical influences on thoracic posture, mobility and stability. The consequences of anatomical variation and degenerative change, their effect on thoracic kyphosis, and the range and patterns of thoracic movement, are examined. The implications for assessment and management of thoracic spine dysfunction are discussed together with some considerations for the application of manual therapy treatment. Copyright 1997 Harcourt Publishers Ltd.

The estimation of vertebral fracture risk in individuals with suspected osteopenia is commonly based on measurements of lumbar spine bone density. The efficacy of vertebral size and deformity, as assessed by vertebral morphometry, in the prediction of fractures has been less studied. In an ex vivo investigation the regional relationships between vertebral size, vertebral deformity, bone density and compressive strength throughout the thoracolumbar spine were examined. In 16 vertebral columns (T1-L5) the bone mineral content (BMC) and bone mineral density (BMD) of each segment were measured using lateral projection dual-energy X-ray absorptiometry, and the vertebral cancellous density (VCD) and mid-vertebral cross-sectional area (CSA) measured using quantitative computed tomography. Vertebral body heights were determined from mid-sagittal CT scans, and vertical height ratios calculated for each segment. The failure load and failure stress of the isolated vertebral bodies were determined using a material testing device. Separate analyses were performed for the upper (T1-4), middle (T5-8) and lower (T9-12) thoracic, and lumbar (L1-5) segments. In all regions, failure load was strongly correlated with BMD (r = 0.82-0.86), moderately correlated with VCD (r = 0.60-0.71) and vertebral height (r = 0.22-0.49), and poorly correlated with the height ratios (r = 0.04-0.33). Failure stress was best predicted by BMD (r = 0.73-0.78) and VCD (r = 0.70-0.78) but was poorly correlated with all morphometric variables (r = 0.01-0.33). The segmental correlations between BMD and VCD ranged form r = 0.49 to r = 0.79. For all regions, BMD and VCD were included in the stepwise regression models for predicting failure load and failure stress. Either the mid-vertebral height or CSA were included in all the failure load models, while mid-vertebral height was included in only one of the failure stress models. The results suggest that vertebral deformity and size (as assessed by vertebral morphometry) make only a minor contribution to the prediction of vertebral strength additional to that provided by bone densitometry alone. The consistent regional relationships between variables appear to support the practice of global fracture risk assessment based on lumbar spine densitometry.

Segmental variations in vertebral body cancellous bone architecture throughout the thoracolumbar spine were examined using histomorphometry and microradiography, and compared to bone mass measured using dual energy X-ray absorptiometry. In six human vertebral columns (T1 to L5) bone mineral content (BMC) and bone mineral density (BMD) of each vertebral body was determined in the lateral projection. Sagittal plane cancellous bone architecture was assessed from two-dimensional surface stained images and microradiographs of two 1 mm thick sections at each vertebral level. Computer-assisted image analysis was used to measure the total bone area (TBA), mean trabecular width (MTW) and trabecular number (TbN) from the stained images, and the skeletonized network length (SNL) from the radiographic images. Consistent segmental trends were observed for all structural parameters across the six columns examined. Higher TBA and TbN values were observed in the upper thoracic segments and decreased caudally. The MTW was relatively constant in the thoracic vertebrae before increasing in the lumbar spine. Pooled correlations between TBA and the bone density measurements were poor (BMC: r = 0.17, BMD: r = 0.25), while the TBA and SNL were only moderately correlated (r = 0.42). In conclusion, histomorphometric and radiological measurements appear to provide different information about cancellous bone structure. Bone structure is poorly correlated to integral measurements of bone mass. The consistent segmental variations in bone architecture appear to reflect a skeletal response to the relative extent of habitually applied loads in different regions of the spine.

Vertebral body geometry, defined by the anterior/posterior (A/P) and mid/posterior (M/P) vertebral body height ratios, was measured in 18 vertebral columns (T1-L5) from sagittal computed tomography scans. For each vertebra, the trabecular density (VTD) and bone mineral density (BMD) were measured using quantitative computed tomography (QCT) and dual-energy X-ray absorptiometry (DXA), respectively. Lateral view radiographs were digitized to measure the thoracic curvature. The segmental correlations between vertebral shape and bone density were poor (r = 0.01-0.31). The mean thoracic BMD and VTD and the mean lumbar VTD were significantly correlated with the mean thoracic A/P ratio (r = 0.55-0.69). The thoracic curvature was significantly correlated with both the mean thoracic and the mean lumbar VTD and BMD (r = 0.55-0.73). In summary, the extent of vertebral wedging and thoracic curvature was moderately indicative of the mean BMD of the thoracic vertebrae, and lumbar spine densitometry is useful to assess the relative severity of osteopenia in individuals with thoracic vertebral deformities.

Study Design: A retrospective survey of thoracic spinal curvature compared postmortem radiographs with recent clinical films in 22 cases., Objectives: This study was performed to determine whether spinal curvature measured from postmortem radiographs is a valid measure of curvature in vivo., Summary of Background Data: Little quantitative data have been cited on whether sagittal plane thoracic spinal curve characteristics change after death., Methods: Thoracic kyphosis was measured using the Cobb method and the mean radius of curvature from computer-assisted digitizing of the vertebral contour. Thoracic segments visualized on the chest films were referenced to the postmortem radiograph., Results and Conclusions: The in vivo and in vitro measurements strongly correlated (Cobb angle r = 0.95, curvature r = 0.78). Trends decreased slightly in Cobb angle (1.3%, -2.6%) and increased slightly in curvature (10.7 mm, 4.1%). Differences were not significant, however, supporting the use of spinal curvature analysis with postmortem radiographs.

The bone density of thoracolumbar vertebral columns (T1-L2) from 12 individuals having a mean age of 73 years was examined using quantitative computed tomography and dual energy X-ray absorptiometry. Spinal units, comprising three vertebrae, from different regions were then tested for compressive strength in a materials test device. Results showed segmental variations in trabecular and integral bone density of the vertebral bodies and their capacity for load bearing. Failure strength increased craniocaudally, whereas failure stress (load/cross-sectional area) decreased. Vertebral compressive strength was moderately correlated with bone mineral density as assessed with dual energy X-ray absorptiometry. In contrast, trabecular bone density determined from quantitative computed tomography was a poor predictor of compressive strength, as was bone mineral content. Use of an integral measure of bone density may provide a more practical guide to bone fragility., (Copyright © 1994. Published by Elsevier Ltd.)

Vertebral bone density of two human vertebral specimens was evaluated using dual-anergy X-ray absorptiometry and single-energy quantitative computed tomography immediately before and after 4 weeks of fixation. The repeated QCT assessment of these segments produced a mean rate of change of 1.17 HU/month, while for DXA the mean rate of change was -0.002 g/month for BMC and -0.0004 g/cm(2)/month for BMD. Ten fresh and 10 fixed sheep lumbar spines underwent absorptiometry before being sectioned into units comprising a central vertebra and adjacent intervertebral discs, plus 1 cm of the flanking vertebral end-plate for embedding into bone cement. The fixed sheep spines underwent a repeat scan after 4 weeks in 10% formalin. Mechanical testing produced a significantly lower average failure load for unfixed specimens (9.3 kN) than for the fixed material (10.8 kN). Failure strain was not significantly different between groups. Linear regression showed a high correlation of BMC values before and after 4 weeks of formalin fixation, while the slopes of the regression for BMD and failure load of both fresh and fixed groups were not significantly different. While formalin fixation may result in a slight increase in compressive strength this does not appear to be associated with a systematic change in mineral density., (Copyright © 1994. Published by Elsevier Ltd.)

Lateral scanning with dual energy X-ray absorptiometry (DXA) was undertaken on 153 thoracic and lumbar vertebral bodies from nine individuals (mean age 67; range 34-92 years) to establish their bone mineral content (BMC). All specimens were subsequently de-fatted and ashed to compare ash weight with BMC of the T1 to L5 segments. Linear regression analysis indicated a higher correlation between BMC and measured ash weights for each vertebral column (range: r = 0.97-0.99), with error for all vertebrae tested showing a standard error of 0.40 g, or 10.8%. For the L2-4 segments the accuracy error was 0.50 g or 7.9%. In both cases there was a mean trend towards underestimation of ash weight. Mean BMC values of the T1 to T5 segments were similar before a progressive increase caudally. These data affirm the utility of DXA for determining bone mineral content in the vertebral column across wide ranges of age, and segmental and bone density.